Search

Codonopsis pilosula is a perennial herbaceous liana with medicinal value. It is critical to promote Codonopsis pilosula growth through effective and sustainable methods, and the use of plant growth-promoting bacteria (PGPB) is a promising candidate. In this study, we isolated a PGPB, Klebsiella michiganensis LDS17, that produced a highly active 1-aminocyclopropane-1-carboxylate deaminase from the Codonopsis pilosula rhizosphere. The strain exhibited multiple plant growth-promoting properties. The antagonistic activity of strain LDS17 against eight phytopathogenic fungi was investigated, and the results showed that strain LDS17 had obvious antagonistic effects on Rhizoctonia solani , Colletotrichum camelliae , Cytospora chrysosperma , and Phomopsis macrospore with growth inhibition rates of 54.22%, 49.41%, 48.89%, and 41.11%, respectively. Inoculation of strain LDS17 not only significantly increased the growth of Codonopsis pilosula seedlings but also increased the invertase and urease activities, the number of culturable bacteria, actinomycetes, and fungi, as well as the functional diversity of microbial communities in the rhizosphere soil of the seedlings. Heavy metal (HM) resistance tests showed that LDS17 is resistant to copper, zinc, and nickel. Whole-genome analysis of strain LDS17 revealed the genes involved in IAA production, siderophore synthesis, nitrogen fixation, P solubilization, and HM resistance. We further identified a gene ( koyR ) encoding a plant-responsive LuxR solo in the LDS17 genome. Klebsiella michiganensis LDS17 may therefore be useful in microbial fertilizers for Codonopsis pilosula . The identification of genes related to plant growth and HM resistance provides an important foundation for future analyses of the molecular mechanisms underlying the plant growth promotion and HM resistance of LDS17., Importance: We comprehensively evaluated the plant growth-promoting characteristics and heavy metal (HM) resistance ability of the LDS17 strain, as well as the effects of strain LDS17 inoculation on the Codonopsis pilosula seedling growth and the soil qualities in the Codonopsis pilosula rhizosphere. We conducted whole-genome analysis and identified lots of genes and gene clusters contributing to plant-beneficial functions and HM resistance, which is critical for further elucidating the plant growth-promoting mechanism of strain LDS17 and expanding its application in the development of plant growth-promoting agents used in the environment under HM stress., Competing Interests: The authors declare no conflict of interest.

An active microbial community of nitrifying and denitrifying bacteria is needed for efficient utilization of nitrogenous compounds from wastewater. In this study, we explored the bacterial community diversity and structure within rivers, treated and untreated wastewater treatment plants (WWTPs) discharging into Lake Victoria. Water samples were collected from rivers and WWTPs that drain into Lake Victoria. Physicochemical analysis was done to determine the level of nutrients or pollutant loading in the samples. Total community DNA was extracted, followed by Illumina high throughput sequencing to determine the total microbial community and abundance. Enrichment and isolation were then done to recover potential nitrifiers and denitrifiers. Physicochemical analysis pointed to high levels total nitrogen and ammonia in both treated and untreated WWTPs as compared to the samples from the lake and rivers. A total of 1,763 operational taxonomic units (OTUs) spread across 26 bacterial phyla were observed with the most dominant phylum being Proteobacteria. We observed a decreasing trend in diversity from the lake, rivers to WWTPs. The genus Planktothrix constituted 19% of the sequence reads in sample J2 collected from the lagoon. All the isolates recovered in this study were affiliated to three genera: Pseudomonas, Klebsiella and Enterobacter in the phylum Proteobacteria. A combination of metagenomic analysis and a culture-dependent approach helped us understand the relative abundance as well as potential nitrifiers and denitrifiers present in different samples. The recovered isolates could be used for in situ removal of nitrogenous compounds from contaminated wastewater., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Complement proteins can form membrane attack complex (MAC) pores that directly kill Gram-negative bacteria. MAC pores assemble by stepwise binding of C5b, C6, C7, C8 and finally C9, which can polymerize into a transmembrane ring of up to 18 C9 monomers. It is still unclear if the assembly of a polymeric-C9 ring is necessary to sufficiently damage the bacterial cell envelope to kill bacteria. In this paper, polymerization of C9 was prevented without affecting binding of C9 to C5b-8, by locking the first transmembrane helix domain of C9. Using this system, we show that polymerization of C9 strongly enhanced damage to both the bacterial outer and inner membrane, resulting in more rapid killing of several Escherichia coli and Klebsiella strains in serum. By comparing binding of wildtype and 'locked' C9 by flow cytometry, we also show that polymerization of C9 is impaired when the amount of available C9 per C5b-8 is limited. This suggests that an excess of C9 is required to efficiently form polymeric-C9. Finally, we show that polymerization of C9 was impaired on complement-resistant E. coli strains that survive killing by MAC pores. This suggests that these bacteria can specifically block polymerization of C9. All tested complement-resistant E. coli expressed LPS O-antigen (O-Ag), compared to only one out of four complement-sensitive E. coli. By restoring O-Ag expression in an O-Ag negative strain, we show that the O-Ag impairs polymerization of C9 and results in complement-resistance. Altogether, these insights are important to understand how MAC pores kill bacteria and how bacterial pathogens can resist MAC-dependent killing., Competing Interests: The authors have declared that no competing interests exist.

Background: Milk being a suitable medium for bacterial growth, it can serve as a source of bacterial contamination. Pathogenic bacteria in milk pose a serious health threat to humans and constitute about 90% of all dairy-related diseases. However, there are few studies that examined the health hazards of raw milk consumption in Ethiopia. Therefore, the objective of this study was to assess the prevalence of bacterial contamination and associated factors in milk produced for commercial purpose in Tigray region, northern Ethiopia., Methods: This study used a cross-sectional study design, selected 315 persons (168 cafeterias, 96 dairy farms, and 51 milk vendors) for interview and collected the same number of bulk raw milk samples using systematic sampling procedure. Data were collected on socio-demographic, farm hygiene and milk handling practices by trained health professionals. Bacterial contamination was defined as total bacterial count (TBC) > 1 × 10 5 , staphylococcus count (SC) > 10 5 , or coliform count (CC) > 10 2  CFU/ml by culture and the species of bacteria were determined by standard biochemical tests., Results: From the 315 milk samples tested, the prevalence of bacterial contamination was 52% (95% CI: 46.5-57.6). The mean counts of contaminated samples of TBC, SC, and CC were 8.94 ± 0.46 Standard Deviation (SD), 8.52 ± 0.6 SD, and 8.78 ± 0.49 SD log CFU/ml, respectively. The proportion of contamination was significantly lower in milk collected from dairy farms (32/96, 33.3, 95% CI: 24.5-43.2) compared to milk from vendors (33/51, 64.7, 95% CI: 51.4-66.2) and cafeterias (99/168, 58.9, 95% CI, 50.9-76.85). The milk samples were culture-positive for Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, K. oxytoca and Citrobacter freundii., Conclusions: Over half of the sampled raw milk exhibited bacterial contamination with increasing trend from farmers to points of sale. Thus, milk vendors and cafeteria owners should apply good hygienic and sanitation practices during handling of milk; use appropriate, clean containers, and cold chain during milk transportation; and refrigeration of milk during storage.

Gut symbiotic bacteria have a substantial impact on host physiology and ecology. However, the contribution of gut microbes to host fitness during long-term low-temperature stress is still unclear. This study examined the role of gut microbiota in host low-temperature stress resistance at molecular and biochemical levels in the oriental fruit fly Bactrocera dorsalis. The results showed that after the gut bacteria of flies were removed via antibiotic treatment, the median survival time was significantly decreased to approximately 68% of that in conventional flies following exposure to a temperature stress of 10°C. Furthermore, we found that Klebsiella michiganensis BD177 is a key symbiotic bacterium, whose recolonization in antibiotic treated (ABX) flies significantly extended the median survival time to 160% of that in the ABX control, and restored their lifespan to the level of conventional flies. Notably, the relative levels of proline and arginine metabolites were significantly downregulated by 34- and 10-fold, respectively, in ABX flies compared with those in the hemolymph of conventional flies after exposure to a temperature stress of 10°C whereas recolonization of ABX flies by K. michiganensis BD177 significantly upregulated the levels of proline and arginine by 13- and 10- fold, respectively, compared with those found in the hemolymph of ABX flies. qPCR analysis also confirmed that K. michiganensis-recolonized flies significantly stimulated the expression of transcripts from the arginine and proline metabolism pathway compared with the ABX controls, and RNAi mediated silencing of two key genes Pro-C and ASS significantly reduced the survival time of conventional flies, postexposure low-temperature stress. We show that microinjection of L-arginine and L-proline into ABX flies significantly increased their survival time following exposure to temperature stress of 10°C. Transmission electron microscopy (TEM) analysis further revealed that low-temperature stress caused severe destruction in cristae structures and thus resulted in abnormal circular shapes of mitochondria in ABX flies gut, while the recolonization of live K. michiganensis helped the ABX flies to maintain mitochondrial functionality to a normal status, which is important for the arginine and proline induction. Our results suggest that gut microbiota plays a vital role in promoting the host resistance to low-temperature stress in B. dorsalis by stimulating its arginine and proline metabolism pathway., Competing Interests: The authors have declared that no competing interests exist.

Objectives: To describe the initial clinical response and care escalation needs for children with urinary tract infections (UTIs) resistant to third-generation cephalosporins while on discordant antibiotics., Methods: We performed a retrospective study of children <18 years old presenting to an acute care setting of 5 children's hospitals and a large managed care organization from 2012 to 2017 with third-generation cephalosporin-resistant UTIs (defined as the growth of ≥50 000 colony-forming units per mL of Escherichia coli or Klebsiella spp. nonsusceptible to ceftriaxone with a positive urinalysis). We included children started on discordant antibiotics who had follow-up when culture susceptibilities resulted. Outcomes were escalation of care (emergency department visit, hospital admission, or ICU transfer while on discordant therapy) and clinical response at follow-up (classified as improved or not improved)., Results: Of the 316 children included, 78% were girls and the median age was 2.4 years (interquartile range 0.6-6.5). Children were evaluated in the emergency department (56%) or clinic (43%), and 90% were started on a cephalosporin. A total of 7 of 316 children (2.2%; 95% confidence interval 0.8%-4.5%) experienced escalation of care. For the 230 children (73%) with clinical response recorded, 192 of 230 (83.5%; 95% confidence interval 78.0%-88.0%) experienced clinical improvement. In children with repeat urine testing while on discordant therapy, pyuria improved or resolved in 16 of 19 (84%) and urine cultures sterilized in 11 of 17 (65%)., Conclusions: Most children with third-generation cephalosporin-resistant UTIs started on discordant antibiotics experienced initial clinical improvement, and few required escalation of care. Our findings suggest that narrow-spectrum empiric therapy is appropriate while awaiting final urine culture results., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2020 by the American Academy of Pediatrics.)

Introduction: Multidrug resistant (MDR) E. coli and Klebsiella infections are rising. IL-1β has been implicated in the differentiation of symptomatic and asymptomatic urinary tract infections, but its role in MDR infections has not been elucidated., Material and Methods: Urinary IL-1β levels were analysed by ELISA., Results: Urinary IL-1β levels were statistically higher in patients with bacterial burden compared to controls and also in patients with MDR bacterial infections compared to those with multidrug-sensitive bacterial infections., Conclusions: Urinary IL-1β levels might be a useful tool to identify patients with challenging MDR bacterial infections.

Chlorimuron-ethyl is a sulfonylurea herbicide with a long residual period in the field and is toxic to rotational crops. Klebsiella jilinsis 2N3 is a gram-negative bacterium that can rapidly degrade Chlorimuron-ethyl. In this study, the gene expression changes in strain 2N3 during degradation of Chlorimuron-ethyl was analyzed by RNA-Seq. Results showed that 386 genes were up-regulated and 453 genes were down-regulated. KEGG pathway enrichment analysis revealed the highest enrichment ratio in the pathway of sulfur metabolism. On the basis of the functional annotation and gene expression, we predicted that carboxylesterase, monooxygenase, glycosyltransferase, and cytochrome P450 were involved in the metabolism of Chlorimuron-ethyl biodegradation. Results of qRT-PCR showed that the relative mRNA expression levels of these genes were higher in treatment group than those in control group. The cytochrome P450 encoded by Kj-CysJ and the alkanesulfonate monooxygenase encoded by Kj-SsuD were predicted and further experimentally confirmed by gene knockout as the key enzymes in the biodegradation process. Cultured in basal medium containing Chlorimuron-ethyl (5  mg L -1 ) in 36 h, the strains of ΔKj-CysJ, ΔKj-SsuD, and WT reached the highest OD 600 values of 0.308, 0.873, and 1.085, and the highest degradation rates of Chlorimuron-ethyl of 11.83%, 96.21%, and 95.62%, respectively., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Antibiotic-resistant bacteria are a significant threat to human health, with one estimate suggesting they will cause 10 million worldwide deaths per year by 2050, surpassing deaths due to cancer 1 . Because new antibiotic development can take a decade or longer, it is imperative to effectively use currently available drugs. Antibiotic combination therapy offers promise for treating highly resistant bacterial infections, but the factors governing the sporadic efficacy of such regimens have remained unclear. Dogma suggests that antibiotics ineffective as monotherapy can be effective in combination 2 . Here, using carbapenem-resistant Enterobacteriaceae (CRE) clinical isolates, we reveal the underlying basis for the majority of effective combinations to be heteroresistance. Heteroresistance is a poorly understood mechanism of resistance reported for different classes of antibiotics 3-6 in which only a subset of cells are phenotypically resistant 7 . Within an isolate, the subpopulations resistant to different antibiotics were distinct, and over 88% of CRE isolates exhibited heteroresistance to multiple antibiotics ('multiple heteroresistance'). Combinations targeting multiple heteroresistance were efficacious, whereas those targeting homogenous resistance were ineffective. Two pan-resistant Klebsiella isolates were eradicated by combinations targeting multiple heteroresistance, highlighting a rational strategy to identify effective combinations that employs existing antibiotics and could be clinically implemented immediately.

Objective: The objective of this study is to determine the prevalence of rectal carriage of plasmid- and chromosome-encoded AmpC β-lactamase-producing Escherichia coli and Klebsiella spp. in patients in a Dutch teaching hospital between 2013 and 2016., Methods: Between 2013 and 2016, hospital-wide yearly prevalence surveys were performed to determine the prevalence of AmpC β-lactamase-producing E. coli and Klebsiella spp. rectal carriage. Rectal swabs were taken and cultured using an enrichment broth and selective agar plates. All E. coli and Klebsiella spp. isolates were screened for production of AmpC β-lactamase using phenotypic confirmation tests and for the presence of plasmid-encoded AmpC (pAmpC) genes. E. coli isolates were screened for chromosome-encoded AmpC (cAmpC) promoter/attenuator alterations., Results: Fifty (2.4%) of 2,126 evaluable patients were identified as rectal carrier of AmpC β-lactamase-producing E. coli. No carriage of AmpC β-lactamase producing Klebsiella spp. was found. Nineteen (0.9%) patients harboured isolates with pAmpC genes and 30 (1,4%) patients harboured isolates with cAmpC promoter/attenuator alterations associated with AmpC β-lactamase overproduction. For one isolate, no pAmpC genes or cAmpC promotor/attenuator alterations could be identified. During the study period, a statistically significant decline in the prevalence of rectal carriage with E. coli with cAmpC promotor/attenuator alterations was found (p = 0.012). The prevalence of pAmpC remained stable over the years., Conclusions: The prevalence of rectal carriage of AmpC-producing E. coli and Klebsiella spp. in patients in Dutch hospitals is low and a declining trend was observed for E. coli with cAmpC promotor/attenuator alterations., Competing Interests: The authors have declared that no competing interests exist.

A methane fermentation digested slurry (MFDS) was evaluated as a substitute for the commercial nutrient, yeast extract (YE), in ethanol production from glycerol by Klebsiella variicola strain TB-83D. In pH-controlled fed-batch cultures, partial replacement of YE by MFDS did not reduce ethanol productivity significantly. However, non-sterilized MFDS had negative effects on glycerol fermentation by this strain. Although ethanol production decreased when YE was completely replaced by sterilized MFDS, the use of crude glycerol and sterilized MFDS achieved a yield of 14.6 g/L ethanol. This is the first study to report the use of MFDS as the sole nutrient for ethanol production from glycerol, which contributes to the development of a low-cost glycerol biorefinery derived from the biodiesel fuel industry., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: In recent years, the world has seen a surge in Enterobacteriaceae resistant to broad-spectrum beta-lactam antibiotics due to the production of extended-spectrum beta-lactamases (ESBLs) or plasmid-mediated AmpC (pAmpC) enzymes. Data on the epidemiology of cephalosporin-resistant Enterobacteriaceae in Sub-Saharan Africa are still limited., Methods: Two hundred seventy-five non-repetitive stool samples were collected from Mozambican university students of both sexes. Samples were cultured on MacConkey agar with and without ceftriaxone (1 mg/L) for selection of third-generation cephalosporin-resistant isolates, which were subjected to antimicrobial susceptibility testing by disc diffusion, characterization of resistance genes by PCR and ERIC-PCR analysis for strain clonality., Results: Among the 275 students, 55 (20%) carried a total of 56 E. coli (n = 35) and Klebsiella spp. (n = 21) isolates resistant to ceftriaxone and phenotypically positive for ESBL- and/or pAmpC-production. Forty-three percent of the isolates (24/56) contained only ESBL genes, 11% (6/56) only pAmpC genes, and 36% (20/56) both ESBL and pAmpC genes. The remaining six isolates were negative for the CTX-M/pAmpC genes included in the test panel. E. coli and Klebsiella spp. combined demonstrated 70% resistance to tetracycline and co-trimoxazole, 63% to ceftazidime and 34% to ciprofloxacin. In total, 89% of ESBL/pAmpC-positive isolates were defined as multi-resistant by being resistant to three or more antibiotic classes. ERIC-PCR fingerprinting demonstrated low similarity among isolates. None of the participants reported recent hospitalization and just 12.5% had taken antibiotics 3 months prior to the study., Conclusion: This study demonstrated 20% colonization with multi-resistant E. coli and Klebsiella spp. among Mozambican students with a diversity of ESBL and pAmpC genes. Colonization was not related to prior hospitalization or antimicrobial consumption.

Methane can be converted to triose dihydroxyacetone (DHA) by chemical processes with formaldehyde as an intermediate. Carbon dioxide, a by-product of various industries including ethanol/butanol biorefineries, can also be converted to formaldehyde and then to DHA. DHA, upon entry into a cell and phosphorylation to DHA-3-phosphate, enters the glycolytic pathway and can be fermented to any one of several products. However, DHA is inhibitory to microbes due to its chemical interaction with cellular components. Fermentation of DHA to d-lactate by Escherichia coli strain TG113 was inefficient, and growth was inhibited by 30 g⋅L -1 DHA. An ATP-dependent DHA kinase from Klebsiella oxytoca (pDC117d) permitted growth of strain TG113 in a medium with 30 g⋅L -1 DHA, and in a fed-batch fermentation the d-lactate titer of TG113(pDC117d) was 580 ± 21 mM at a yield of 0.92 g⋅g -1 DHA fermented. Klebsiella variicola strain LW225, with a higher glucose flux than E. coli , produced 811 ± 26 mM d-lactic acid at an average volumetric productivity of 2.0 g -1 ⋅L -1 ⋅h -1 Fermentation of DHA required a balance between transport of the triose and utilization by the microorganism. Using other engineered E. coli strains, we also fermented DHA to succinic acid and ethanol, demonstrating the potential of converting CH 4 and CO 2 to value-added chemicals and fuels by a combination of chemical/biological processes., Competing Interests: The authors declare no conflict of interest.

Background: Failure to timely diagnose and treat urinary tract infections is associated with grave long term consequences. The objectives of this study included assessing the proportion and predictors of Urinary Tract Infection (UTI) as a cause of pediatric outpatient department (OPD) visits and determining common uropathogens with antimicrobial susceptibility pattern., Methods: A cross sectional study was conducted from May to September 2015 among children of less than 15 years old at a tertiary center in Hawassa, Ethiopia. Children who fulfilled predefined eligibility criteria were recruited to undergo urine culture and urine analysis., Results: A total of 863 children visited the OPD during the study period among which 269(31.2%) fulfilled the predefined eligibility criteria. Urine culture was positive for 74/269(27.5%) of the clinically suspected children. Male uncircumcision (adjusted odds ratio (aOR) 3.70; 95% CI 1.34-10.16) and under nutrition (aOR 5.41; 95%CI 2.64-11.07) were independent predictors of culture positivity. More than 5 WBC per high power field (aOR 4.7, 95% CI 1.8-12.7) on microscopy, urine PH > 5.0 (aOR 2.6, 95%CI 1.2-5.8), and positive leukocyte esterase (aOR 9.9, 95%CI 4.1-25.7) independently predicted positive growth on urine culture. Escherichia coli (34/74, 45.9%) and Klebsiella spp (18/74, 24.3%) were the most frequent isolates. High resistance was noted against amoxicillin (70.6%) and cotrimoxazole (97.1%) by E. coli., Conclusion: UTI accounted for a tenth of total OPD visits. Commonly used first line antibiotics showed high level resistance to common etiologies of UTI. UTI should be suspected in febrile children, and antibiograms should be done to tailor prescription of antibiotics.

Disulfides from Allium stipitatum, commonly known as Persian shallot, were previously reported to possess antibacterial properties. Analogues of these compounds, produced by S-methylthiolation of appropriate thiols using S-methyl methanethiosulfonate, exhibited antimicrobial activity, with one compound inhibiting the growth of Mycobacterium tuberculosis at 17 µM (4 mg L -1 ) and other compounds inhibiting Escherichia coli and multi-drug-resistant (MDR) Staphylococcus aureus at concentrations ranging between 32-138 µM (8-32 mg L -1 ). These compounds also displayed moderate inhibitory effects on Klebsiella and Proteus species. Whole-cell phenotypic bioassays such as the spot-culture growth inhibition assay (SPOTi), drug efflux inhibition, biofilm inhibition and cytotoxicity assays were used to evaluate these compounds. Of particular note was their ability to inhibit mycobacterial drug efflux and biofilm formation, while maintaining a high selectivity towards M. tuberculosis H37Rv. These results suggest that methyl disulfides are novel scaffolds which could lead to the development of new drugs against tuberculosis (TB).

This study investigates the impacts of influent ammonium concentrations on the microbial community in immobilized heterotrophic ammonium removal system. Klebsiella sp. FC61, the immobilized species, has the ability to perform simultaneous ammonium removal and Fe 3+ reduction. It was found that average ammonium removal rate decreased from 0.308 to 0.157 mg/L/h, as the influent NH 4 + -N was reduced from 20 to 10 mg/L. Meanwhile, at a total Fe 3+ concentration of 20 mg/L, the average Fe 3+ reduction removal efficiency and rate decreased from 44.61% and 0.18 mg/L/h, to 27.10% and 0.11 mg/L/h, respectively. High-throughput sequencing was used to observe microbial communities in bioreactor Samples B1, B2, and B3, after exposure to different influent NH 4 + -N conditions. Results show that higher influent NH 4 + -N concentrations increased microbial richness and diversity and that Klebsiella sp. FC61 play a functional role in the simultaneous removal of NH 4 + -N and Fe 3+ reduction in bioreactor systems.

Background: Antimicrobial photodynamic therapy (APDT) is a process that generates reactive oxygen species (ROS) in presence of photosensitizer, visible light and oxygen which destroys the bacterial cells. We investigated the photoinactivation efficiency of phenothiazinium dyes and the effect of ROS generation on Gram positive and Gram negative bacterial cell as well as on biofilm., Material and Methods: Enterococcus faecalis and Klebsiella pneumonia were incubated with all the three phenothiazinium dyes and exposed to 630nm of light. After PDT, colony forming unit (CFU) were performed to estimate the cell survival fraction. Intracellular reactive oxygen species (ROS) was detected by DCFH-DA. Crystal violet (CV) assay and extracellular polysaccharides (EPS) reduction assay were performed to analyze antibiofilm effect. Confocal laser electron microscope (CLSM) scanning electron microscope (SEM) was performed to assess the disruption of biofilm., Results: 8log 10 reduction in bacterial count was observed in Enterococcus faecalis while 3log 10 in Klebsiella pneumoniae. CV and EPS reduction assay revealed that photodynamic inhibition was more pronounced in Enterococcus faecalis. In addition to this CLSM and SEM study showed an increase in cell permeability of propidium iodide and leakage of cellular constituents in treated preformed biofilm which reflects the antibiofilm action of photodynamic therapy., Conclusion: We conclude that Gram-positive bacteria (Enterococcus faecalis) are more susceptible to APDT due to increased level of ROS generation inside the cell, higher photosensitizer binding efficiency and DNA degradation. Phenothiazinium dyes are proved to be highly efficient against both planktonic and biofilm state of cells., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae strains are increasing in prevalence worldwide. Carbapenem antibiotics are used as a first line of therapy against ESBL-producing Enterobacteriaceae We examined a cohort of critical care patients for gastrointestinal colonization with carbapenem-resistant ESBL-producing strains (CR-ESBL strains). We cultured samples from this cohort of patients for ESBL-producing Klebsiella spp. and Escherichia coli and then tested the first isolate from each patient for susceptibility to imipenem, doripenem, meropenem, and ertapenem. Multilocus sequence typing was performed on isolates that produced an ESBL and that were carbapenem resistant. Among all patients admitted to an intensive care unit (ICU), 4% were positive for an ESBL-producing isolate and 0.64% were positive for a CR-ESBL strain on surveillance culture. Among the first ESBL-producing E. coli and Klebsiella isolates from the patients' surveillance cultures, 11.2% were carbapenem resistant. Sequence type 14 (ST14), ST15, ST42, and ST258 were the dominant sequence types detected in this cohort of patients, with ST15 and ST258 steadily increasing in prevalence from 2006 to 2009. Patients colonized by a CR-ESBL strain were significantly more likely to receive antipseudomonal and anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) therapy prior to ICU admission than patients colonized by carbapenem-susceptible ESBL-producing strains. They were also significantly more likely to have received a cephalosporin or a carbapenem antibiotic than patients colonized by carbapenem-susceptible ESBL-producing strains. In conclusion, in a cohort of patients residing in intensive care units within the United States, we found that 10% of the isolates were resistant to at least one carbapenem antibiotic. The continued emergence of carbapenem-resistant ESBL-producing strains is of significant concern, as infections due to these organisms are notoriously difficult to treat., (Copyright © 2017 American Society for Microbiology.)

Bacterial isolates were collected from patients hospitalized with pneumonia (PHP), including ventilator-associated pneumonia (VAP), from 76 U.S. medical centers in 2011 to 2015. The Gram-negative organisms ( n = 11,185, including 1,097 from VAP) were tested for susceptibility to ceftazidime-avibactam and comparators by the broth microdilution method. β-Lactamase-encoding genes were screened using a microarray-based assay on selected isolates. Pseudomonas aeruginosa and Klebsiella spp. were the most common Gram-negative bacteria isolated from PHP and VAP. Ceftazidime-avibactam was very active against P. aeruginosa ( n = 3,402; MIC 50 /MIC 90 , 2 and 4 μg/ml; 96.6% susceptible), including isolates nonsusceptible to meropenem (86.3% susceptible to ceftazidime-avibactam), piperacillin-tazobactam (85.6% susceptible), or ceftazidime (80.6% susceptible). Ceftazidime-avibactam was also highly active against Enterobacteriaceae (MIC 50 /MIC 90 , 0.12 and 0.5 μg/ml; 99.9% susceptible), including carbapenem-resistant Enterobacteriaceae (CRE) ( n = 189; MIC 50 /MIC 90 , 0.5 and 2 μg/ml; 98.0% susceptible) and multidrug-resistant (MDR) ( n = 674; MIC 50 /MIC 90 , 0.25 and 1 μg/ml; 98.8% susceptible) and extensively drug-resistant (XDR) ( n = 156; MIC 50 /MIC 90 , 0.5 and 2 μg/ml; 98.1% susceptible) Enterobacteriaceae isolates, as well as Klebsiella species isolates showing an extended-spectrum β-lactamase (ESBL) screening-positive phenotype ( n = 433; MIC 50 /MIC 90 , 0.25 and 1 μg/ml; 99.5% susceptible). Among Enterobacter spp. (24.8% ceftazidime nonsusceptible), 99.8% of the isolates, including 99.4% of ceftazidime-nonsusceptible isolates, were susceptible to ceftazidime-avibactam. The most common β-lactamases detected among Klebsiella pneumoniae and E. coli isolates were K. pneumoniae carbapenemase (KPC)-like and CTX-M-15, respectively. Only 8 of 6,209 Enterobacteriaceae isolates (0.1%) were ceftazidime-avibactam nonsusceptible, three NDM-1-producing strains with ceftazidime-avibactam MIC values of >32 μg/ml and five isolates with ceftazidime-avibactam MIC values of 16 μg/ml and negative results for all β-lactamases tested. Susceptibility rates among isolates from VAP were generally similar or slightly higher than those from all PHP., (Copyright © 2017 American Society for Microbiology.)

2,3-Butanediol (2,3-BD) is a promising bulk chemical with a potentially wide range of applications e.g., in the manufacture of printing inks, perfumes, synthetic rubber, fumigants, antifreeze agents, fuel additives, foodstuffs and pharmaceuticals. Its high heating value and ability to increase the octane number of fuels make 2,3-BD a promising drop-in fuel. It can also be converted to methyl-ethyl ketone (MEK), which is considered an effective liquid fuel additive. After combination with MEK and hydrogenation reaction, 2,3-BD can be converted to octane, which is used to produce high-quality aviation fuel. Currently 2,3-BD is mainly produced on an industrial scale by chemical methods. However, microbiological production of 2,3-BD offers a less expensive and more environmentally friendly alternative to traditional synthesis. This alcohol is generated from hexoses and pentoses mainly by bacterial strains of the genera Klebsiella, Bacillus, Serratia, and Enterobacter, which can convert waste products (such as glycerol and agricultural residues) and excess biomass (such as wood hydrolysates) to 2,3-BD. Recently, a significant improvement in microbial production has been achieved by the screening of efficient natural microbial strains, the application of alternative cost-effective substrates, and the genetic improvement of microbial producers. Furthermore, Klebsiella strains, which are regarded the most efficient natural 2,3-BD producers, have been subjected to genetic modifications aiming at the removal of pathogenic factors and the development of avirulent strains that could be used for the safe production of the diol. This review summarizes existing knowledge and experience concerning various strategies for efficient and economical microbial production of 2,3-BD.

In this study, two strains of Bdellovibrio were isolated from soil samples using the culture-dependent technique and two members of the family Enterobacteriaceae (Klebsiella sp. and Salmonella sp.) as prey. The Bdellovibrio strains were bacteriolytic, plaque-forming, and highly motile gram-negative bacteria. We identified and confirmed the Bdellovibrio strains using microscopy, PCR amplification, and sequencing of the 16S rRNA gene. They were observed to be different strains based on hit locus and prey range analyses. Here, the first report on Bdellovibrio strains isolated from soil in Mexico corroborates earlier report indicating that populations of Bdellovibrio found in soil are heterogeneous thereby the need to identify the various strains., (© 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Background: Sepsis is one of the most common causes of neonatal deaths globally. Most sepsis-related deaths occur in low-income and middle-income countries, where the epidemiology of neonatal sepsis remains poorly understood. Most of these countries lack proper surveillance networks, hampering accurate assessment of the burden of sepsis, implementation of preventive measures, and investment in research. We report results of neonates born in hospital from a multicentre collaboration on neonatal sepsis., Methods: In this cohort study, dedicated research teams prospectively followed up neonates born in one of three tertiary care centres in Delhi, India (Vardhaman Mahavir Medical College, Maulana Azad Medical College, and All India Institute of Medical Sciences [coordinating centre]) and subsequently admitted to the intensive care unit. Neonates were followed up daily until discharge or death. On clinical suspicion, neonates underwent sepsis work-up including blood cultures. The isolated organisms were identified and tested for antimicrobial susceptibility. We defined Gram-negative isolates resistant to any three of five antibiotic classes (extended-spectrum cephalosporins, carbapenems, aminoglycosides, fluoroquinolones, and piperacillin-tazobactam) as multidrug resistant., Findings: 13 530 neonates of 88 636 livebirths were enrolled between July 18, 2011, and Feb 28, 2014. The incidence of total sepsis was 14·3% (95% CI 13·8-14·9) and of culture-positive sepsis was 6·2% (5·8-6·6). Nearly two-thirds of total episodes occurred at or before 72 h of life (defined as early onset; 1351 [83%] of 1980). Two-thirds (645 [64%]) of 1005 isolates were Gram-negative including, Acinetobacter spp (22%), Klebsiella spp (17%), and Escherichia coli (14%). The pathogen mix in early-onset sepsis did not differ from that of late-onset sepsis (ie, after 72 h). High rates of multidrug resistance were observed in Acinetobacter spp (181/222, 82%), Klebsiella spp (91/169, 54%), and Escherichia coli (52/137, 38%) isolates. Meticillin resistance prevailed in 61% (85/140) of coagulase-negative staphylococci and 38% (43/114) of Staphylococcus aureus isolates. Nearly a quarter of the deaths were attributable to sepsis. The population-attributable risks of mortality were 8·6% in culture-negative sepsis, 15·7% in culture-positive sepsis by multidrug-resistant organisms, and 12·0% in culture-positive sepsis by non-multidrug-resistant organisms., Interpretation: The high incidence of sepsis and alarming degree of antimicrobial resistance among pathogens in neonates born in tertiary hospitals underscore the need to understand the pathogenesis of early-onset sepsis and to devise measures to prevent it in low-income and middle-income countries., Funding: Indian Council of Medical Research., (Copyright © 2016 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY license. Published by Elsevier Ltd.. All rights reserved.)

Staphylococcus aureus is presently regarded as an emerging zoonotic agent due to the spread of specific methicillin-resistant S. aureus (MRSA) clones in pig farms. Studying the microbiota can be useful for the identification of bacteria that antagonize such opportunistic veterinary and zoonotic pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium system. Carriers and non-carriers were selected on the basis of quantitative longitudinal data on S. aureus carriage in 600 pigs sampled at 20 Danish herds included in two previous studies in Denmark. Raw sequences were analysed with the BION meta package and the resulting abundance matrix was analysed using the DESeq2 package in R to identify operational taxonomic units (OTUs) with differential abundance between S. aureus carriers and non-carriers. Twenty OTUs were significantly associated to non-carriers, including species with known probiotic potential and antimicrobial effect such as lactic acid-producing isolates described among Leuconostoc spp. and some members of the Lachnospiraceae family, which is known for butyrate production. Further 5 OTUs were significantly associated to carriage, including known pathogenic bacteria such as Pasteurella multocida and Klebsiella spp. Our results show that the nasal microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate these bacteria and assess their possible antagonistic effect on S. aureus for the pursuit of new strategies to control MRSA in pig farming.

Bacteriological analysis was conducted in 136 patients with an acute purulent cholangitis (APCH). The APCH causes were: choledocholithiasis--in 40 (29.9%) patients, coexistence of a common biliary duct stricture and choledocholithiasis--in 39 (28.7%), compression of external biliary ducts by the oedematous pancreatic head in secondary pancreatitis--in 15 (11%), pericholedocheal lymphadenitis--in 3 (2.2%).

The chromogenic synthetic medium "Klebsiella 5-ASK CHROM-C was developedfor isolation and identification of klebsiellae of species of K. pneumoniae subsp. pneumoniae K. oxytoca, K. mobilis according chromogenic reaction to enzyme 5-aminosalycilate decarboxylase as a unique marker of genus Klebsiella. The L-proline and L-calcium glutamate are used as a source of nitrogen and carbon in medium. The consistency of composition of growth medium that ensure its regularity. The diagnostic sensitivity of chromogenic medium is 95.3 ± 1.7%; diagnostic specificity is 100%; analytical sensitivity is 1-2 colony-forming units per ml-1. The identification of Klebsiella is achieved simultaneously with their isolation during 24 = 48 hours. The test of 5-ASK decarboxylase using two chromogenic mediums "Klebsiella 5-ASK CHROM-C" permits identifying additionally K. pneumoniae subsp, ozaenae, K .pneumoniae subsp. Rhinoscleromatis.

Antibiotic resistance in Gram-negative microorganisms is an increasing health care problem. The rapid detection of such resistance is crucial for starting an early specific therapy and to enable initiation of the required hygiene measures. With continued emphasis on reducing the cost of laboratory testing, only economical/low-cost approaches have a chance of being implemented. During recent years, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been developed to be a standard method in microbiology laboratories for the rapid and cost-efficient identification of microorganisms. Extending the usage of MALDI-TOF MS in the clinical microbiology laboratory to the area of resistance testing is an attractive option. Quantitative MALDI-TOF MS using an internal standard facilitates the measurement of the quantity of peptides and small proteins within a spectrum. These quantities correlate to the number of microorganisms and therefore to the growth of a microorganism. The comparison of growth in the presence or absence of an antibiotic allows for analysis of the susceptibility behavior of a strain. Here, we describe a novel method and its application in the analysis of 108 Klebsiella sp. isolates. After 1 h of incubation at a meropenem concentration of 8 μg/ml, a sensitivity of 97.3% and a specificity of 93.5% were achieved (compared to Etest results)., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

The results of biological research of colon microbiota of patients with rheumatoid arthritis (RA) is in article presented. The signs of III degree dysbiosis, by reducing the concentration of Bacteroides spp., Bifidobacterium spp., Lactobacillus spp. populations, typical strain E. coli. But over growth of populations Klebsiella spp., Proteus spp., Staphylococcus spp., atypical forms of E. coli, Candida spp. The scheme for the correction of the colon microflora of patients with (RA) by was proposed bifiform. Increasing of populations concentration of Bifidobacterium spp., Bacteroides spp., Lactobacillus spp., typical E. coli, Enterococcus spp. and selective decontamination of Enterococcus (Hly+), Klebsiella spp., Proteus spp., Staphylococcus spp., lactosonegative and E.coli (Hly+) confirmed after using of this eubiotics.

Synergism between biocides and antibiotics was investigated in 20 biocide and antibiotic-resistant bacterial strains that were previously isolated from organically produced foods, according to their antimicrobial resistance profiles. Most of the antibiotic/biocide combinations yielded synergistic interactions, reducing the inhibitory concentrations of biocides and antibiotics by 4- to 16-fold. Among enterococci, synergism with biocides was detected for amoxicillin (AM), cefuroxime (CX), erythromycin (EM), ciprofloxacin (CP), and trimethoprim/sulphametoxazol (T/S). Among staphylococci, interactions were synergistic (AM) and either synergistic or indifferent (CX and EM, depending on biocide). Among the three methicillin-resistant Staphylococcus aureus clinical strains included in the study, the combinations of methicillin and triclosan or hexachlorophene acted synergistically in all strains, but interactions were either synergistic or indifferent for the other biocides, depending on the strain. All combinations tested were synergistic for Lactobacillus (AM, CX, EM, and CP) and Micrococcus (AM, EM). In Salmonella, interactions were indifferent (AM, CX, EM, and CP) or synergistic (T/S). Synergism with biocides was also detected in Klebsiella isolates (AM, CX, and T/S), Enterobacter sp. (AM, CX, EM, and T/S), Pantoea (AM, CX, EM, CP, and T/S), and Chryseobacterium sp. (EM). These results suggest that combinations of biocides and antibiotics may open new possibilities to combat antimicrobial resistance.

Contemporary (2012) β-lactamase-producing isolates (n=493) from U.S. hospitals were tested against ceftaroline-avibactam. Klebsiella spp., Escherichia coli and Proteus mirabilis isolates displaying the Clinical and Laboratory Standards Institute (CLSI) screening criteria for extended spectrum β-lactamase (ESBL) production were evaluated. Isolates carried genes encoding CTX-M (n=316, CTX-M-14-like and -15-like), KPC (n=45), CMY-2-like (n=54), or SHV enzyme with ESBL activity (n=78). Ceftaroline-avibactam inhibited 98.2% of the isolates at ≤0.5 μg/mL, and all strains were inhibited by ≤2 μg/mL of this novel β-lactamase-inhibitor combination. These results confirm that ceftaroline-avibactam could be a useful therapeutic option for Enterobacteriaceae isolates producing β-lactamases that are prevalent in the United States.

Capacity of Klebsiella planticola strain TSJhA-91 for synthesis of indolyl-3-acetic acid (IAA) and other auxins was studied. The qualitative and quantitative composition of these compounds depends on the presence of exogeneous tryptophan and on the nitrogen source. The highest IAA yield was obtained at the stationary phase of growth. Addition of L-tryptophan to the medium resulted in a significant increase (up to 85.5 microg/mL) of auxin biosynthesis, especially in the presence of nitrates. Thin-layer chromatography revealed that the indole-3-acetamide pathway was not active in this strain. The biological activity of auxins was confirmed by plant assay with the kidney bean cuttings; the height of root formation and rdot number increased 16- and 6-fold, respectively. Under conditions of low-temperature stress, protective effect of K. planticola TSKhA-91 on development of cucumbers (Cucumissativus L.) seeds, including stimulation of germi- nation and root formation by its seeds were shown.

Biofilms contain a diverse range of microorganisms and their varying extracellular polysaccharides. The present study has revealed biofilm succession associated with degradative effects on plastic (polypropylene) and contaminants in sludge. The wet weight of biofilm significantly (p < 0.05) increased; from 0.23 ± 0.01 to 0.44 ± 0.01 g. Similarly, the dry weight of the biofilm increased from 0.02 to 0.05 g. Significant reduction in pathogens (E. coli and feacal coliforms) by MPN technique (>80%) and in chemical parameters (decrease in COD, BOD5 of 73.32 and 69.94%) representing diminution of organic pollutants. Energy dispersive X-ray spectroscopy (EDS) of plastic revealed carbon and oxygen contents, further surface analysis of plastic by scanning electron microscopy (SEM) revealed emergence of profound bacterial growth on the surface. Fourier transform infrared (FTIR) spectroscopy conforms its biotransformation under aerobic conditions after 8 weeks. New peaks developed at the region 1050 and 969 cm(-1) indicating CO and CC bond formation. Thus plastic with 6 weeks old aerobic biofilm (free of pathogens, max. weight, and OD, efficient COD & BOD removal ability) is suggested to be maintained in fixed biofilm reactors for wastewater treatment., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Biodiesel fuel (BDF) waste contains large amounts of crude glycerol as a by-product, and has a high alkaline pH. With regard to microbial conversion of ethanol from BDF-derived glycerol, bacteria that can produce ethanol at alkaline pH have not been reported to date. Isolation of bacteria that shows maximum productivity under alkaline conditions is essential to effective production of ethanol from BDF-derived glycerol. In this study, we isolated the Klebsiella variicola TB-83 strain, which demonstrated maximum ethanol productivity at alkaline pH. Strain TB-83 showed effective usage of crude glycerol with maximum ethanol production at pH 8.0-9.0, and the culture pH was finally neutralized by formate, a by-product. In addition, the ethanol productivity of strain TB-83 under various culture conditions was investigated. Ethanol production was more efficient with the addition of yeast extract. Strain TB-83 produced 9.8 g/L ethanol (0.86 mol/mol glycerol) from cooking oil-derived BDF waste. Ethanol production from cooking oil-derived BDF waste was higher than that of new frying oil-derived BDF and pure-glycerol. This is the first report to demonstrate that the K. variicola strain TB-83 has the ability to produce ethanol from glycerol at alkaline pH., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The Regional Resistance Surveillance program monitored susceptibility rates and developing resistance by geographic region, including 12 Asia-Pacific (APAC) countries. Reference broth microdilution methods for susceptibility/interpretations were applied, processing 5,053 strains. Among Staphylococcus aureus isolates (37% methicillin-resistant S. aureus [MRSA], highest in South Korea [73%]), linezolid (LZD), tigecycline (TIG), and vancomycin were 100% active, but 33 and 34% of strains were levofloxacin (LEV) or macrolide resistant, respectively. Streptococcus pneumoniae was most resistant to β-lactams and macrolides (45%) but was LZD, LEV, and TIG susceptible (>98%). Extended-spectrum β-lactamase (ESBL) phenotype rates in Escherichia coli and Klebsiella spp. were 48 and 47%, respectively, and were highest in Taiwan, at 75 to 91%. The best anti-ESBL-phenotype agents were amikacin (81 to 96% susceptible), colistin (COL; >98%), TIG (>98%), and carbapenems (81 to 97%). Pseudomonas aeruginosa showed ≥20% resistance to all drugs except COL (99% susceptible). In conclusion, endemic evolving antimicrobial resistances in APAC nations show compromised roles for many commonly used antimicrobials.

Background: Nosocomial bloodstream infections (nBSIs) are an important cause of morbidity and mortality and are the most frequent type of nosocomial infection in pediatric patients., Methods: We identified the predominant pathogens and antimicrobial susceptibilities of nosocomial bloodstream isolates in pediatric patients (≤16 years of age) in the Brazilian Prospective Surveillance for nBSIs at 16 hospitals from 12 June 2007 to 31 March 2010 (Br SCOPE project)., Results: In our study a total of 2,563 cases of nBSI were reported by hospitals participating in the Br SCOPE project. Among these, 342 clinically significant episodes of BSI were identified in pediatric patients (≤16 years of age). Ninety-six percent of BSIs were monomicrobial. Gram-negative organisms caused 49.0% of these BSIs, Gram-positive organisms caused 42.6%, and fungi caused 8.4%. The most common pathogens were Coagulase-negative staphylococci (CoNS) (21.3%), Klebsiella spp. (15.7%), Staphylococcus aureus (10.6%), and Acinetobacter spp. (9.2%). The crude mortality was 21.6% (74 of 342). Forty-five percent of nBSIs occurred in a pediatric or neonatal intensive-care unit (ICU). The most frequent underlying conditions were malignancy, in 95 patients (27.8%). Among the potential factors predisposing patients to BSI, central venous catheters were the most frequent (66.4%). Methicillin resistance was detected in 37 S. aureus isolates (27.1%). Of the Klebsiella spp. isolates, 43.2% were resistant to ceftriaxone. Of the Acinetobacter spp. and Pseudomonas aeruginosa isolates, 42.9% and 21.4%, respectively, were resistant to imipenem., Conclusions: In our multicenter study, we found a high mortality and a large proportion of gram-negative bacilli with elevated levels of resistance in pediatric patients.

A microbial-flocculants-producing (MBF-producing) bacterium, named TG-1, was isolated from waste water of a starch factory, and identified as Klebsiella sp. TG-1. The microbial flocculants (MBF) produced by TG-1, named as MBF-TG-1, was applied to defecating the strong basic trona suspension in the trona industry. After optimizing medium and culturing conditions with single-factor and orthogonal designs, the highest flocculation rate of 86.9% was achieved. Chemical analysis showed that the purified microbial flocculants (MBF-TG-1) was mainly composed of polysaccharides (84.6%), with a small amount of protein or amino acid (11.1%). Bridging mechanism was supposed as the main flocculation mechanism by analyzing the flocculation process and the biochemistry properties of MBF-TG-1. The high flocculation rate (84%) was also achieved with a low-cost medium (the solid residue of tofu production from food industry)., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objective: The aim of the present study was to investigate the most effective probiotic combinations to prevent death and necrotizing enterocolitis (NEC) in a premature rat model., Methods: One hundred fifty-eight premature Sprague-Dawley premature rats were enrolled. Probiotic strains Bifidobacterium bifidum, B longum, Lactobacillus acidophilus, L plantarum, and B breve were fed as a single strain or mixture with 2 or 3 strains for a total of 9 study groups; control groups received no exogenous probiotic supplement. Fecal samples were collected for 72 hours to detect probiotic strains and pathologic strains by real-time polymerase chain reaction. Colony counts of probiotic strains Escherichia coli and Klebsiella were compared between groups before and after 36 hours of the study period. The incidence of death and NEC were compared via Fisher exact test between groups., Results: The results demonstrated that L plantarum alone (P = 0.0026) and B bifidum with B longum together (P = 0.0017) were more effective in reducing NEC as compared with the control group. All of the study groups except B breve and B bifidum with B breve definitely prevented death compared with controls. B bifidum and B longum together had significantly lower mortality than the control group (P < 0.0001). Colony counts of E coli and Klebsiella in stool samples were significantly decreased in the B bifidum, B longum, and L plantarum group compared with the other study and control groups after 36 hours., Conclusions: Administration of a mixture of probiotic strains with B bifidum and B longum was most effective in preventing death and NEC in this animal model, and these observations provide an evidence-based strategy for designing further neonatal clinical trials.

The novel exopolysaccharide HZ-7 is produced by Klebsiella sp. H-207, and its fermentation conditions were optimized by response surface methodology (RSM). In this study, the optimized medium consisted of sucrose 31.93 g/L, KNO(3) 2.17 g/L and K(2)HPO(4) 5.47 g/L; while the optimized culture conditions consisted of seed age 13 h, with an inoculum size of 10.6% and incubation temperature of 28.9°C. A maximum HZ-7 yield of about 15.05 g/L was achieved under the optimized conditions using RSM and single-factor experiments. Next the exopolysaccharide HZ-7 was partially purified and characterized. The resulting product showed good properties, such as high concentration of uronic acid (41.67%), low average molecular weight (about 1.94×10(5) Da) and porous surface structure, were very advantageous to biosorption. Therefore HZ-7 was applied to absorb hexavalent chromium (Cr(VI)). The maximum adsorption efficiency (99.2%) which was obtained at an initial pH of 1.0 along with an initial Cr(VI) concentration of 20 mg/L, was not affected by ordinary metal ions and temperature. These data suggest Klebsiella sp. H-207 exopolysaccharide will be promising potential for industrial application.

Objectives: The double-disk synergy test was compared to the Mastdiscs™ ID AmpC and ESßL method for detection of ESßL production in rectal swab., Methods: Two hundred and forty-nine rectal swabs were directly inoculated onto Mueller-Hinton plates and analyzed according to both methods., Results: A total of 41 (16%) and 208 (84%) were positive and negative for ESßL, respectively. Twelve (29%) and 20 (49%) of the 41 rectal swabs positive for ESßL were detected after 24h of incubation with the double-disk synergy test and the Mastdiscs™ method, respectively (P=0.013). One hundred fifty-eight (76%) et 183 (88%) of the 208 rectal swabs were detected negative for ESßL after 24h of incubation with the double-disk synergy test and the Mastdiscs™ method, respectively (P<0.001). Finally, 79 (32%) and 46 (18%) rectal swabs respectively inoculated according to the double-disk synergy test and the Mastdiscs™ method were inconclusive after 24h of incubation. The better performance of the Mastdiscs™ method was due to an easier detection of cephalosporinase producing bacteria., Conclusions: The Mastdiscs™ method is a simple phenotypic method that detects more easily ESßL and non-ESßL producing bacteria in rectal swab., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

The leading cause of nosocomial infections and spread of multiresistant bacteria is considered to be the failure of healthcare workers to perform appropriate hand hygiene. The role of the hands of hospital patients in the spread of infection has received little attention. The aim of the present study was to investigate the occurrence of potentially pathogenic bacteria on the patients' hands. Quantitative cultures were repeatedly taken from the fingertips of patients at a rehabilitation clinic before and after an intervention in which patient hand disinfection was introduced and promoted. Before the intervention, the occurrence on the hands of Escherichia coli, Klebsiella spp., enterococci, Staphylococcus aureus and yeast was a common finding. The colony counts of S. aureus were often higher than the counts of other organisms. After the intervention, the level of hand contamination was lower. The difference was statistically significant (p < 0.05) concerning Enterobacteriaceae, both when the patients were resting and at lunch time, for enterococci and total bacterial counts at lunch time, and for yeast when they were resting. Concerning S. aureus, the difference was not statistically significant, neither while resting nor at lunch time. The role of the patients in the spread of pathogenic bacteria merits more discussion., (© 2012 The Authors APMIS © 2012 APMIS.)

Aim: Study of taxonomical structure ofwound infection agents, prevalence of mixes, and detection of character of their possible connection with the results of various microorganisms population interaction in septic wounds., Materials and Methods: A microbiological study of material from patients with wound infection (WI), 582 of those were cured in reanimation and intensive therapy departments (RITD; group 1) and 1455 - in surgical departments (SD; group 2), was performed. Taxonomic membership and ability to coexist was determined in 4129 microorganisms strains. Etiological role of the agents was evaluated by using values of consistency rate (CR). Species that were present in more than 50% of samples were considered consistent, in 25 to 50%--additional, and in less than 25%--random. Frequency rates (FR) were also determined, that is the fraction of a certain species (genus) of the microorganism (in %) from all the isolated cultures that correspond to 100%. For the determination of the significance of individual species of the agent in the structure of mixed microorganism populations, FR - their fraction (%) in mixed population from the number of strains of this species that correspond to 100% - was calculated., Results: A significant part of the microorganisms strains, more frequently in reanimation department (65.5%), caused wound suppuration in populations mixed with other species of the agents. In reanimation and surgical departments consistent species of wound infection agents were not detected. A leading etiological role of Staphylococcus aureus (FR 19.2% and 23.9%) was determined, and FR of S. aureus strains in mixes was 64.6% in RITD and 46.8% in SD. The parameters ofotheragents of WI in the comparison groups were similar. However FR among mixes in RITD were significantly higher for streptococci that do not belong to S. pyogenes species (72,5%), and also nonfermentative microorganisms (67,2%), and in SD - in Klebsiella pneumoniae mixes. For agents of wound infection especially in RITD, low species diversity was characteristic and the number of mixes variants is significantly higher. In RITD mixed infections develop more frequently, and the ecological community of microorganisms reaches higher values than in SD., Conclusion: During the analysis of microbiologi-cal data in RITD and SD general patterns and specific features of taxonomical structure, prevalence of mixed populations and character of their ecological community in wound infection was determined.

For a long time it was thought that Bursaphelenchus xylophilus was the only agent of the pine wilt disease. Recently, it was discovered that there are bacteria associated with the nematodes that contribute to the pathogenesis of this disease, mainly through the release of toxins that promote the death of the pines. Among the species most commonly found, are bacteria belonging to the Bacillus, Pantoea, Pseudomonas and Xanthomonas genera. The main objective of this work was to study the effect of inoculation of maritime pine (Pinus pinaster) with four different nematode isolates, in the bacterial population of nematodes and trees, at different stages of disease progression. The monitoring of progression of disease symptoms was also recorded. Also, the identification of bacteria isolated from the xylem of trees and the surface of nematodes was performed by classical identification methods, by the API20E identification system and by sequencing of bacterial DNA. The results showed that for the symptoms progression, the most striking difference was observed for the pines inoculated with the avirulent isolate, C14-5, which led to a slower and less severe aggravation of symptoms than in pines inoculated with the virulent isolates. In general, it was found that bacterial population, inside the tree, increased with disease progression. A superior bacterial quantity was isolated from pines inoculated with the nematode isolates HF and 20, and, comparatively, few bacteria were isolated from pines inoculated with the avirulent isolate. The identification system API20E was insufficient in the identification of bacterial species; Enterobacter cloacae species was identified in 79% of the isolated bacterial colonies and seven of these colonies could not be identified by this method. Molecular identification methods, through bacterial DNA sequencing, allowed a more reliable identification: eleven different bacterial species within the Bacillus, Citrobacter, Enterobacter, Escherichia, Klebsiella, Paenibacillus, Pantoea and Terribacillus genera were identified. General bacterial diversity increased with the progression of the disease. Bacillus spp. were predominant at the earlier stage of disease progression and Klebsiella oxytoca at the later stages. Furthermore, bacterial species isolated from the surface of nematodes were similar to those isolated from the xylem of pines. In the present work new bacterial species were identified which have never been reported before in this type of study and may be associated with their geographical origin (Portugal). P. pinaster, the pine species used in this study, was different from those commonly grown in Japan and China. Furthermore, it was the first time that bacteria were isolated and identified from an avirulent pine wood nematode isolate., (Copyright © 2011 Elsevier Inc. All rights reserved.)

In most studies dealing with the laboratory cultivation of paramecia (Paramecium bursaria), Klebsiella pneumoniae bacteria are used to inoculate the medium. However, Klebsiella pneumoniae is a typical pathogen, and its use is always associated with a risk of infection. The aim of the present research was to examine non-pathogenic bacteria strains as components of the medium for Paramecium bursaria. The paramecia were incubated on lettuce infusions bacterized with different bacteria strains: Bacillus subtilis DSM 10, Bacillus megaterium DSM 32, Escherichia coli DSM 498, Micrococcus luteus DSM 348. A strain derived from the natural habitat of Paramecium bursaria was used as the control one. Experiments were conducted under constant light and in the dark. Paramecia cells were counted under a stereomicroscope on consecutive days of incubation. The obtained results show that the most intensive growth of Paramecium bursaria occurs in the presence of Escherichia coli DSM 498. The use of this strain as a component of the medium allows one to obtain a high number of ciliates regardless of the light conditions. It can be concluded that the Paramecium bursaria cultivation procedure can be modified by using the non-pathogenic bacteria strain Escherichia coli DSM 498 instead of Klebsiella pneumoniae.

This study evaluated the impact of the Uro-Quick (UQ) screening system (Alifax, Italy) for a rapid and accurate reporting of urine cultures, and whether it can provide bacterial yield to be used in identification and susceptibility testing. A total of 1480 urine samples collected between October 2006 and July 2008 were tested by conventional culture (CC) methods and UQ simultaneously. Sediments of positive UQ vials were used as bacterial yields for identification and susceptibility testing procedures. Of the 1480 samples, 999 revealed bacteria and/or leukocytes in direct microscopy. Among these 999 samples, positive growth was detected in 420 (42%) and 433 (43.3%) by UQ and CC, respectively. However, only 0.6% of samples without bacteria and leukocytes exhibited positive growth. When compared to CC, UQ demonstrated high levels of positive predictive value (95.9%), negative predictive value (94.8%), sensitivity (93%) and specificity (96.9%). Both CC isolates and UQ bacteria showed 81.3% concordance in identification results. Susceptibility testing of UQ bacteria displayed >90% agreement, when compared with standardized disk diffusion test. Our results indicate that UQ can reliably be used in routine laboratories giving microbial growth results in 3 hours. The most significant part of the study is that bacterial yields of UQ positive samples can be used in identification and susceptibility testing, allowing a rapid, same-day reporting of urine cultures.

Studies to design a dry chromogenic nutrient medium for the diferentiation of Klebsiella were under way, by detecting the intracellular Klebsiella genus-specific enzyme of human potential pathogenicity--5-aminosalicylate decarboxylase. The composition of the proposed medium that ensured its high sensitivity and improved its differentiating properties as compared with the known traditional media was worked through. Klebsiella are isolated and identified on the proposed medium in one step, which substantially reduces diagnosis time and material costs and takes some burden from microbiologists.

Purpose: To evaluate the efficacy of disinfecting solutions in hydrophilic contact lenses (CL)., Methods: Two multi-use solutions denominated solution A (0.001% polyquaternium-1 and 0.0005% myristamidopropyl dimethylamine) and solution B (0.0001% polyaminopropyl biguanide) were used. The solutions were tested in hydrophilic contact lenses infected with Pseudomonas aeruginosa (ATCC27583), Staphylococcus epidermidis (ATCC1226), Klebsiella pneumoniae (ATCC13883), Staphylococcus aureus (ATCC25923) and Candida albicans (ATCC 10231) and the decrease in microorganisms growth after the hydrophilic contact lenses were cleaned with the respective solutions was verified. The manufacture's instructions were followed., Results: A decrease of 90% of Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus, Candida albicans and a decrease 100% of Klebsiella pneumoniae was observed., Conclusion: The solutions decreased the amount of microorganisms tested.

Aims: To identify the types of micro-organisms involved in the formation of biofilms on dairy ultrafiltration and reverse osmosis membranes and investigate factors affecting the attachment of those isolates., Methods and Results: Micro-organisms isolated from industrial membranes following standard cleaning were identified using the API culture identification system. Thirteen different isolates representing eight genera were isolated and their ability to attach to surfaces was compared using a microtitre plate assay. Three Klebsiella strains attached best, while mixed strains of Pseudomonas and Klebsiella attached better than individual strains. Whey enhanced the attachment of the isolates. The micro-organisms were characterized according to cell surface hydrophobicity using the microbial adhesion to hydrocarbon (MATH) test, and cell surface charge by measuring the zeta potential. These cell surface characteristics did not show a clear relationship with the attachment of our strains., Conclusions: A variety of different micro-organisms is associated with dairy ultrafiltration and reverse osmosis membranes after cleaning, suggesting several possible sources of contamination. The cleaning of these membranes may be inadequate. The attachment of the different isolates is highly variable and enhanced in the presence of whey., Significance and Impact of the Study: Knowledge of persistent microflora colonizing dairy membrane systems will help develop strategies to mitigate biofilm development in this environment, improving hygiene in membrane processing plants.

A bio-trickling filter (BTF) packed with polyhedral spheres was used to remove nitrogen oxides (NOx) from the flue gas of a coal-fired power plant. The BTF system consistently removed 64-95% of the NOx after start-up and acclimation under dynamic conditions (e.g., 120-240 m(3)/h flue gas flow rate and inlet 300-900 mg NOx/m(3)). Scanning electron microscopy of the biofilms that were formed showed a shift in the predominating bacteria. Analyses by PCR-denaturing gradient gel electrophoresis showed that the naturally-selected mixed cultures in the biofilm under a flue gas environment were mainly Klebsiella sp. and Pseudomonas sp.

Aims: To explore new resources of methane-utilizing micro-organism and develop a microbial biosensing system for monitoring methane released from natural and semi-natural ecosystems., Methods and Results: A methane (CH(4))-utilizing bacterial strain was isolated from paddy soil using CH(4) as the sole carbon source and identified as Klebsiella sp. ME17 by phenotyping and 16S rDNA sequence analysis. The efficiency of CH(4) utilization of strain ME17 was 83.2% by gas chromatography analysis. A microbial biosensing system for CH(4) detection was developed by combining immobilized cells of strain ME17 with a dissolved oxygen sensor. It was found that response time of the system to CH(4) was <90s. The dissolved O(2) consumption increased with increasing CH(4) from 0% to 16.0% (v/v) demonstrating a positive linear relationship with a low detection limit of 0.2% (v/v). The relative standard deviation is 3.48%., Conclusions: Klebsiella sp. ME17 isolate is capable of utilizing CH(4). The microbial biosensing system of strain ME17 has been successfully applied to measure standard CH(4) sample with satisfactory results., Significance and Impact of the Study: This study suggests that certain strains of Klebsiella genus are capable of utilizing CH(4). Our proposed method appears very attractive for CH(4) measurement in coal mine.

Bacterial biofilm formation on inert surfaces is a significant health and economic problem in a wide range of environmental, industrial, and medical areas. Bacterial adhesion is generally a prerequisite for this colonization process and, thus, represents an attractive target for the development of biofilm-preventive measures. We have previously found that the preconditioning of several different inert materials with an aqueous fish muscle extract, composed primarily of fish muscle alpha-tropomyosin, significantly discourages bacterial attachment and adhesion to these surfaces. Here, this proteinaceous coating is characterized with regards to its biofilm-reducing properties by using a range of urinary tract infectious isolates with various pathogenic and adhesive properties. The antiadhesive coating significantly reduced or delayed biofilm formation by all these isolates under every condition examined. The biofilm-reducing activity did, however, vary depending on the substratum physicochemical characteristics and the environmental conditions studied. These data illustrate the importance of protein conditioning layers with respect to bacterial biofilm formation and suggest that antiadhesive proteins may offer an attractive measure for reducing or delaying biofilm-associated infections.

Bacterial counts were compared in free-stall mattresses and teat ends exposed to 5 treatments in a factorial study design on 1 dairy farm. Mattresses in five 30-cow groups were subjected to 1 of 5 bedding treatments every other day: 0.5 kg of hydrated limestone, 120 mL of commercial acidic conditioner, 1 kg of coal fly ash, 1 kg of kiln-dried wood shavings, and control (no bedding). Counts of coliforms, Klebsiella spp., Escherichia coli, and Streptococcus spp. were lowest on mattresses bedded with lime. Mattresses bedded with the commercial acidic conditioner had the next lowest counts for coliforms, Klebsiella spp., and Streptococcus spp. Wood shavings and the no-bedding control had the highest counts for coliform and Klebsiella spp. Compared with wood shavings or control, fly ash reduced the counts of coliforms, whereas for the other 3 bacterial groups, the reduction was not always significant. Streptococcus spp. counts were greatest in the control group and did not differ among the shavings and fly ash groups. Teat swab results indicated that hydrated lime was the only bedding treatment that significantly decreased the counts of both coliforms and Klebsiella spp. There were no differences in Streptococcus spp. numbers on the teats between any of the bedding treatments. Bacterial populations grew steadily on mattresses and were generally higher at 36 to 48 h than at 12 to 24 h, whereas bacterial populations on teats grew rapidly by 12 h and then remained constant. Hydrated lime was the only treatment that significantly reduced bacterial counts on both mattresses and teat ends, but it caused some skin irritation.