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β-Lactamases (Bla) and low-affinity penicillin-binding proteins (PBP2A) are responsible for β-lactam resistance in the genera Macrococcus, Mammaliicoccus and Staphylococcus. These resistance mechanisms are in most species acquired through mobile genetic elements that carry a blaZ-like β-lactamase gene for penicillin resistance and/or a mec gene (mecA, mecB, mecC,mecD) encoding a PBP2A for resistance to virtually all classes of β-lactams. The mecA and mecC genes can be acquired through staphylococcal cassette chromosome mec (SCCmec) elements in Staphylococcus and Mammaliicoccus. The mecB and mecD genes are found in Macrococcus on SCCmec elements, as well as on unrelated mecD-carrying Macrococcus resistance islands (McRImecD) and large mecB-carrying plasmids. This review provides a phylogenetic overview of Macrococcus, Mammaliicoccus and Staphylococcus species and an in-depth analysis of the genetic structures carrying bla and mec genes in these genera. Native bla genes were detected in species belonging to the novobiocin-resistant Staphylococcus saprophyticus group and Mammaliicoccus. The evolutionary relatedness between Macrococcus and Mammaliicoccus is illustrated on the basis of a similar set of intrinsic PBPs, especially, the presence of a second class A PBP. The review further focuses on macrococcal elements carrying mecB and mecD, and compares them with structures present in Staphylococcus and Mammaliicoccus. It also discusses the different recombinases (ccr of SCCmec) and integrases (int of McRI) that contribute to the mobility of methicillin resistance genes, revealing Macrococcus as an important source for mobilization of antibiotic resistance genes within the family of Staphylococcaceae., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The occurence and spread of animal-derived methicillin resistant staphylococci (MRS) worldwide is a current problem, especially due to their increasing incidence in food animals and their products, with possible contamination of food consumers and handlers. Staphylococci isolated from animals (n = 123) were identified with MALDI-TOF mass spectrometry and screened for methicillin/oxacillin/cefoxitin resistance (MR) using the disk diffusion method. Twenty-three phenotypically MRS strains were analysed using PBP2' Latex Agglutination Test Kit to confirm the phenotypic MR and PCR was performed for mecA gene detection; mecA gene positive strains were furtherly confirmed by means of sequencing. The susceptibility of MRS to 11 partially-purified enterocins (Ent) produced by E. faecium, E. durans and E. mundtii strains of animal, feed/food and environmental origin was checked using agar spot tests. Out of 23 MRS, PBP testing confirmed MR in 17 strains. Three Staphylococcus epidermidis and one S. vitulinus were mecA positive. The majority of MRS, including two mecA gene-positive strains S. epidermidis R44/1 and P3/Tr2a, were susceptible to the tested enterocins, mainly to Ent7420, EntA(P)/EK13, Ent412, Ent55 and Ent9296 (in the range 100 - 12,800 AU/mL). The most susceptible strains appeared to be the mecA gene-positive S. epidermidis SE R44/1 and SE P3/Tr2a strains, inhibited by eight enterocins out of 11 tested (100-200 AU/mL). Only four strains (including mecA gene positive S. epidermidis SE P3/Tr1 and S. vitulinus SV K12PL/1) were resistant to the tested antimicrobial substances. These results indicate that the enterocins used offer a promising option for prevention and treatment of bacterial infection caused by MRS in animals., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

A hemolytic Macrococcus canis strain (LI021) was isolated for the first time from a human skin infection. The complete genome of LI021 consisting of a 2,216,765-bp circular chromosome was obtained by de novo hybrid assembly of Illumina and Oxford Nanopore technology reads. Strain LI021 belonged to the new sequence type ST75 and was resistant to β-lactam antibiotics due to the presence of a methicillin resistance gene mecB. The mecB gene as well as putative hemolysin genes hlgB and hlgC were located on a novel composite pseudo (Ψ) SCCmec island. These findings show that a methicillin-resistant M. canis may be associated with human infection and indicate that this bacterium should be considered by human diagnostic laboratories., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

The global impact of methicillin-resistant Staphylococcus aureus (MRSA) clonal lineages on human and animal health continues, even considering the decreasing MRSA rates in some parts of the world [...].

Chromosomal resistance islands containing the methicillin resistance gene mecD (McRI mecD ) have been reported in Macrococcus caseolyticus Here, we identified novel macrolide resistance genes in Macrococcus canis on similar elements, called McRI msr These elements were also integrated into the 3' end of the 30S ribosomal protein S9 gene ( rpsI ), delimited by characteristic attachment ( att ) sites, and carried a related site-specific integrase gene ( int ) at the 5' end. They carried novel macrolide resistance genes belonging to the msr family of ABC subfamily F (ABC-F)-type ribosomal protection protein [ msr (F) and msr (H)] and the macrolide efflux mef family [ mef (D)]. Highly related mef (D)- msr (F) fragments were found on diverse McRI msr elements in M. canis , M. caseolyticus, and Staphylococcus aureus Another McRI msr -like element identified in an M. canis strain lacked the classical att site at the 3' end and carried the msr (H) gene but no neighboring mef gene. The expression of the novel resistance genes in S. aureus resulted in a low-to-moderate increase in the MIC of erythromycin but not streptogramin B. In the mef (D)- msr (F) operon, the msr (F) gene was shown to be the crucial determinant for macrolide resistance. The detection of circular forms of McRI msr and the mef (D)- msr (F) fragment suggested mobility of both the island and the resistance gene subunit. The discovery of McRI msr in different Macrococcus species and S. aureus indicates that these islands have a potential for dissemination of antibiotic resistance within the Staphylococcaceae family., (Copyright © 2020 American Society for Microbiology.)

Macrococcus caseolyticus belongs to the normal bacterial flora of dairy cows and does not usually cause disease. However, methicillin-resistant M. caseolyticus strains were isolated from bovine mastitis milk. These bacteria had acquired a chromosomal island (McRI mecD -1 or McRI mecD -2) carrying the methicillin resistance gene mecD To gain insight into the distribution of McRI mecD types in M. caseolyticus from cattle, 33 mecD -containing strains from Switzerland were characterized using molecular techniques, including multilocus sequence typing, antibiotic resistance gene identification, and PCR-based McRI mecD typing. In addition, the same genetic features were analyzed in 27 mecD -containing M. caseolyticus strains isolated from bovine bulk milk in England/Wales using publicly available whole-genome sequences. The 60 strains belonged to 24 different sequence types (STs), with strains belonging to ST5, ST6, ST21, and ST26 observed in both Switzerland and England/Wales. McRI mecD -1 was found in different STs from Switzerland ( n  = 19) and England/Wales ( n  = 4). McRI mecD -2 was only found in 7 strains from Switzerland, all of which belonged to ST6. A novel island, McRI mecD -3, which contains a complete mecD operon ( mecD-mecR1 m -mecI m [where the subscript m indicates Macrococcus ]) combined with the left part of McRI mecD -2 and the right part of McRI mecD -1, was found in heterogeneous STs from both collections (Switzerland, n  = 7; England/Wales, n  = 21). Two strains from England/Wales carried a truncated McRI mecD -3. Phylogenetic analyses revealed no clustering of strains according to geographical origin or carriage of McRI mecD -1 and McRI mecD -3. Circular excisions were also detected for McRI mecD -1 and McRI mecD -3 by PCR. The analyses indicate that these islands are mobile and may spread by horizontal gene transfer between genetically diverse M. caseolyticus strains. IMPORTANCE Since its first description in 2017, the methicillin resistance gene mecD has been detected in M. caseolyticus strains from different cattle sources and countries. Our study provides new insights into the molecular diversity of mecD -carrying M. caseolyticus strains by using two approaches to characterize mecD elements: (i) multiplex PCR for molecular typing of McRI mecD and (ii) read mapping against reference sequences to identify McRI mecD types in silico In combination with multilocus sequence typing, this approach can be used for molecular characterization and surveillance of M. caseolyticus carrying mecD ., (Copyright © 2019 American Society for Microbiology.)

Objectives: To analyse the genetic context of mecB in two Macrococcus canis strains from dogs, compare the mecB-containing elements with those found in other Macrococcus and Staphylococcus species, and identify possible mobilizable mecB subunits., Methods: Whole genomes of the M. canis strains Epi0076A and KM0218 were sequenced using next-generation sequencing technologies. Multiple PCRs and restriction analysis confirmed structures of mecB-containing elements, circularization and recombination of mecB subunits., Results: Both M. canis strains contained novel composite pseudo (Ψ) staphylococcal cassette chromosome mec (SCCmec) elements. Integration site sequences for SCC flanked and subdivided composite ΨSCCmecEpi0076A (69569 bp) into ΨSCC1Epi0076A-ΨSCCmecEpi0076A-ΨSCC2Epi0076A and composite ΨSCCmecKM0218 (24554 bp) into ΨSCCKM0218-ΨSCCmecKM0218. Putative γ-haemolysin genes (hlgB and hlgC) were found at the 3' end of both composite elements. ΨSCCmecKM0218 contained a complete mecB gene complex (mecIm-mecR1m-mecB-blaZm) downstream of a new IS21-family member (ISMaca1). ΨSCCmecEpi0076A carried a blaZm-deleted mecB gene complex similar to that reported in 'Macrococcus goetzii' CCM4927T. A second mecB gene was found on the 81325 bp MDR plasmid pKM0218 in KM0218. This plasmid contained a complete Tn6045-associated mecB gene complex distinct from that of ΨSCCmecKM0218. pKM0218 was almost identical to the mecB-containing plasmid recently reported in Staphylococcus aureus (overall 99.96% nucleotide identity). Mobilization of mecB within an unconventional circularizable structure was observed in Epi0076A as well as chromosomal plasmid insertion via recombination of mecB operons in KM0218., Conclusions: Our findings provide evidence of both the continuing evolution of mecB-containing elements in macrococci and M. canis as a potential source of the mecB-containing plasmid found in staphylococci., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Antimicrobial resistance is one of the major public health emergencies worldwide, and this trend didn't spare developing countries like Ethiopia. The objective of this study was to evaluate patterns of bacterial isolates and local antimicrobial susceptibility patterns in neonatal sepsis., Methods: A hospital based observational study was conducted from April 2016 to May 2017 in Asella teaching and referral hospital (ATRH). A total of 303 neonates with clinical sepsis were included. Collected data were entered into EPI-INFO version 3.5.1 for cleanup; and then exported to SPSS version 21 for further analysis. Frequencies and proportion were used to describe the study population in relation to relevant variables., Results: Bacterial growth was detected in 88 (29.4%) of blood cultures. Predominantly isolated bacteria were coagulase negative staphylococci (CoNS) 22 (25%), Escherichia coli (E.Coli) 18 (20.5%) and Staphylococcus aureus 16 (18%). Resistance rates of S. aureus and CoNS against Ampicillin were 11 (69%) and 20 (91%) respectively. The resistance rate of E. coli against Ampicillin and Gentamycin were 12 (66.7%) and 10 (55.6%) while Klebsiella spp. resistance rate gets much higher against these two first line antibiotics [10 (91%) and 9 (82%) respectively]. Similarly, both Gram-positive and Gram-negative bacteria isolates were also highly resistant to third generation Cephalosporins, and 63 (72%) isolated bacteria showed multidrug-resistance. However; Gram-positive bacteria isolates had better susceptibility patterns to third line antibiotics like Clindamycin, Vancomycin and Ciprofloxacin while Gram-negative isolates had a higher susceptibility to Ciprofloxacin and Amikacin., Conclusion: CoNS, S. aureus , E. coli and Klebsiella spp. were the leading bacterial causes of neonatal sepsis in our study. They were highly resistant to first- and second-line empiric antimicrobial treatment used at NICU (Neonatal intensive care unit), reducing the antimicrobial choices for management of neonatal sepsis. Fortunately, the mentioned isolated bacteria remained susceptible to third line antibiotics used to treat neonatal sepsis., Competing Interests: The research proposal was presented and approved by the Institutional Review Board of Arsi University and ethical clearance was obtained with ethical clearance certificate number of CoHS/CS/001/2016/17. Individual verbal consent of participation was obtained from mothers/ care givers of eligible neonates before starting interviews/laboratory sampling. The participation was purely voluntary and confidentiality and privacy were maintained by conducting interviews in separate spaces whenever possible. Benefits of the laboratory test were clearly communicated to mothers/care givers and for patients whose blood culture results showed positive growth, susceptibility-based antibiotics were started.Not applicable.The authors declare that there is no competing and conflict of interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Aim: To compare the in vitro activity of the anti-impetigo agent, ozenoxacin, and other antimicrobial agents against Gram-positive clinical isolates from skin and soft tissue infections., Materials & Methods: Isolates were collected in two studies: 1097 isolates from 49 centers during 2009-2010 and 1031 isolates from ten centers during 2014. Minimum inhibitory concentrations were determined for 18 and 11 antimicrobials in these studies, respectively, using standard broth microdilution methods. Isolates were stratified by species and methicillin susceptibility/resistance and/or levofloxacin susceptibility/nonsusceptibility status., Results: Ozenoxacin exhibited high in vitro activity against Staphylococcus aureus and coagulase-negative staphylococci isolates in both studies. Ozenoxacin was also highly active against Streptococcus pyogenes and Streptococcus agalactiae isolates., Conclusion: Ozenoxacin is a potent antimicrobial agent against staphylococci and streptococci.

The Gram-positive genus Macrococcus is composed of eight species that are evolutionarily closely related to species of the Staphylococcus genus. In contrast to Staphylococcus species, species of Macrococcus are generally regarded to be avirulent in their animal hosts. Recent reports on Macrococcus have focused on the presence of novel methicillin resistance genes in Macrococcus caseolyticus and Macrococcus canis, with the discovery of the first plasmid-encoded methicillin resistance gene in clinical Staphylococcus aureus of probable macrococcal origin generating further interest in these organisms. Furthermore, M. caseolyticus has been associated with flavor development in certain fermented foods and its potential as a food bio-preservative has been documented. The potential application of these organisms in food seems at odds with the emerging information regarding antibiotic resistance and is prompting further examination of the potential safety issues associated with such strains, given the European Food Safety Authority framework for the safety evaluation of microorganisms in the food chain. A comprehensive understanding of the genus would also contribute to understanding the evolution of staphylococci in terms of its acquisition of antibiotic resistance and pathogenic potential. In this review, we discuss the current knowledge on Macrococcus with regard to their phenotypic capabilities, genetic diversity, and evolutionary history with Staphylococcus. Comparative genomics of the sequenced Macrococcus species will be discussed, providing insight into their unique metabolic features and the genetic structures carrying methicillin resistance. An in-depth understanding of these antibiotic resistance determinants can open the possibilities for devising better preventative strategies for an unpredictable future., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Three new prenylated furoquinoline alkaloids named lecomtequinoline A ( 1 ), B ( 2 ), and C ( 3 ), together with the known compounds anhydroevoxine ( 4 ), evoxine ( 5 ), dictamnine ( 6 ), N- methylflindersine ( 7 ), evoxanthine ( 8 ), hesperidin, lupeol, β -sitosterol, stigmasterol, β -sitosterol-3- O - β -d-glucopyranoside, stearic acid, and myristyl alcohol, were isolated by bioassay-guided fractionation of the methanolic extracts of leaves and stem of Vepris lecomteana . The structures of compounds were determined by spectroscopic methods (NMR, MS, UV, and IR) and by comparison with previously reported data. Crude extracts of leaves and stem displayed high antimicrobial activity, with Minimum Inhibitory Concentration (MIC) (values of 10.1-16.5 and 10.2-20.5 µg/mL, respectively, against Escherichia coli , Bacillus subtilis , Pseudomonas agarici , Micrococcus luteus , and Staphylococcus warneri , while compounds 1 - 6 showed values ranging from 11.1 to 18.7 µg/mL or were inactive, suggesting synergistic effect. The extracts may find application in crude drug preparations in Western Africa where Vepris lecomteana is endemic, subject to negative toxicity results in vivo ., Competing Interests: The authors declare no conflict of interest.

Key Message: Prevalence of diverse PPM™-tolerant endophytic bacteria in papaya, the broad-spectrum microbicide specified for use in plant tissue cultures, capable of surviving covertly in MS-based medium, with implications in contamination management. Plant Preservative Mixture™ was employed for establishing papaya (Carica papaya) tissue cultures from field explants. Comparing three recommended practices for controlling endogenous microbial contaminants, axillary shoot tips (1.0-1.5 cm) from cv. Arka Prabhath were treated with PPM™ 5% for 4 h (T1), 50% for 10 min (T2) or 100% for 10 min (T3) and cultured in MS-based papaya establishment medium (PEM). By 4-6 weeks, all treatments proved non-rewarding with cultures succumbing either to microbial contamination (80% in T1) or phytotoxicity effect/contamination (90% in T2 and 95% in T3). Another trial adopting a multi-step surface sterilization treatment (carbendazim-cetrimide-HgCl 2 ) followed by culturing in 0.05% PPM-supplemented PEM showed 35% obvious bacterial contamination compared with 40% in control. Single colonies from pooled bacterial growths were tested on 0.1% PPM-incorporated nutrient agar (NA) registering 60% isolates as PPM sensitive. Twenty PPM-surviving isolates were selected and identified. This showed 85% Gram-positive bacteria including 80% under phylum Firmicutes (55% spore-forming Bacillaceae and 25% Staphylococcaceae) and 5% Actinobacteria, and 15% Gram-negative Proteobacteria. About 50% isolates remained wholly non-obvious upon culturing on PEM while the rest showed slow growth with many displaying growth enhancement upon host tissue extract supplementation. Culturing the isolates on PPM-supplemented NA indicated 90-95% as tolerating 0.05-0.1% PPM and 65% overriding 0.2% PPM. The isolates, however, did not display obvious growth in PPM-supplemented PEM where the spore formers survived. The results indicate the prevalence of diverse PPM™-tolerant endophytic bacteria in papaya most of which survive covertly in MS-based medium and the need for taking this into account while using PPM™ for contamination management.

The present study investigated the effect of cinnamon essential oil on the quality of vacuum-packaged common carp (Cyprinus carpio) fillets stored at 4±1°C in terms of sensory scores, physicochemical characteristics (total volatile basic nitrogen (TVB-N), biogenic amines, and color), and presence of spoilage microbiota. A total of 290,753 bacterial sequences and 162 different genera belonging to 14 phyla were observed by a high-throughput sequencing technique targeting the V3-V4 region of 16S rDNA, which showed a more comprehensive estimate of microbial diversity in carp samples compared with microbial enumeration. Before storage, Macrococcus and Aeromonas were the prevalent populations in the control samples, but cinnamon essential oil decreased the relative abundance of Macrococcus in the treated samples. Variability in the predominant microbiota in different samples during chilled storage was observed. Aeromonas followed by Lactococcus were the major contaminants in the spoiled control samples. Microbial enumeration also observed relatively higher counts of Aeromonas than other spoilage microorganisms. Compared with the control samples, cinnamon essential oil inhibited the growth of Aeromonas and Lactococcus were the predominant components in the treated samples on day 10; plate counts also revealed a relatively high level of lactic acid bacteria during refrigerated storage. However, there were no significant differences (P>0.05) in the composition of dominant microbiota between these two treatments at the end of the shelf-life. Furthermore, cinnamon essential oil treatment was more effective in inhibiting the increase of TVB-N and the accumulation of biogenic amines (especially for putrescine and cadaverine levels). Based primarily on sensory analysis, the use of cinnamon essential oil extended the shelf-life of vacuum-packaged common carp fillets by about 2days., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Marine actinobacteria have been considered as a gold mine with respect to great potential regarding their secondary metabolites. Most of the researches have been conducted on actinobacteria's derived secondary metabolites to examine its pharmacological properties. Actinobacteria have a potential to provide future drugs against crucial diseases, such as drug-resistance bacteria, cancer, a range of viral illnesses, malaria, several infections and inflammations. Although, the mode of action of many bio molecules are still untapped, for a tangible number of compounds by which they interfere with human pathogenesis are reported here with detailed diagrammed illustrations. This knowledge is one of the basic vehicles to be known especially for transforming bio medicinal molecules to medicines. Actinobacteria produce a different kind of biochemical substances with numerous carbon skeletons, which have been found to be the main component interfering with human pathogenesis at different sites. Different diseases have the capability to fight at different sites inside the body can lead to a new wave of increasing the chances to produce targeted medicines., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Some new derivatives of substituted-4(3H)-quinazolinones were synthesized and evaluated for their in vitro antitumor and antimicrobial activities. The results of this study demonstrated that compound 5 yielded selective activities toward NSC Lung Cancer EKVX cell line, Colon Cancer HCT-15 cell line and Breast Cancer MDA-MB-231/ATCC cell line, while NSC Lung Cancer EKVX cell line and CNS Cancer SF-295 cell line were sensitive to compound 8. Additionally, compounds 12 and 13 showed moderate effectiveness toward numerous cell lines belonging to different tumor subpanels. On the other hand, the results of antimicrobial screening revealed that compounds 1, 9 and 14 are the most active against Staphylococcus aureus ATCC 29213 with minimum inhibitory concentration (MIC) of 16, 32 and 32 μg/mL respectively, while compound 14 possessed antimicrobial activities against all tested strains with the lowest MIC compared with other tested compounds. In silico study, ADME-Tox prediction and molecular docking methodology were used to study the antitumor activity and to identify the structural features required for antitumor activity.

Biofilms cause persistent bacterial infections and are extremely recalcitrant to antimicrobials, due in part to reduced penetration of antimicrobials into biofilms that allows bacteria residing in the depth of a biofilm to survive antimicrobial treatment. Here, we describe the preparation of surface-adaptive, Triclosan-loaded micellar nanocarriers showing (1) enhanced biofilm penetration and accumulation, (2) electrostatic targeting at acidic pH toward negatively charged bacterial cell surfaces in a biofilm, and (3) antimicrobial release due to degradation of the micelle core by bacterial lipases. First, it was established that mixed-shell-polymeric-micelles (MSPM) consisting of a hydrophilic poly(ethylene glycol) (PEG)-shell and pH-responsive poly(β-amino ester) become positively charged at pH 5.0, while being negatively charged at physiological pH. This is opposite to single-shell-polymeric-micelles (SSPM) possessing only a PEG-shell and remaining negatively charged at pH 5.0. The stealth properties of the PEG-shell combined with its surface-adaptive charge allow MSPMs to penetrate and accumulate in staphylococcal biofilms, as demonstrated for fluorescent Nile red loaded micelles using confocal-laser-scanning-microscopy. SSPMs, not adapting a positive charge at pH 5.0, could not be demonstrated to penetrate and accumulate in a biofilm. Once micellar nanocarriers are bound to a staphylococcal cell surface, bacterial enzymes degrade the MSPM core to release its antimicrobial content and kill bacteria over the depth of a biofilm. This constitutes a highly effective pathway to control blood-accessible staphylococcal biofilms using antimicrobials, bypassing biofilm recalcitrance to antimicrobial penetration.

Macrococcus bovicus was locally isolated from soil and used in the green synthesis of nano-scaling silver (NSAg). It was immobilized on a sodic-montmorillonite clay (MMT1) and cetyltrimethylammonium bromide-modified montmorillonite (MMT2) which was also calcined at 300 °C (MMT3). The NSAg clays were characterized by X-ray fluorescence, Fourier transform infrared spectra, X-ray diffractometry, surface area measurement, UV-Vis spectrometry, scanning electron microscope, transmission electron microscope and thermogravimetric analysis. NSAg was confirmed to be included in the interparticular cavities of the clay sheets and its mechanical stability was evidenced. The antimicrobial activity of the NSAg-modified clays was investigated against Staphylococcus aureus, Escherichia coli and Candida albicans using the cup plate and the plate count techniques. The antimicrobial activity of the NSAg clays was confirmed and attributed to the caging of NSAg in MMT cavities. MMT3 was found to inhibit the microbial growth to as high as 65 % as observed from the plate count method. Graphical Abstract Scheme of the biosynthesis of nano-scaling Ag and its immobilization and antimicrobial application.

The mammalian gut microbiota harbors a diverse ecosystem where hundreds of bacterial species interact with each other and their host. Given that bacteria use signals to communicate and regulate group behaviors (quorum sensing), we asked whether such communication between different commensal species can influence the interactions occurring in this environment. We engineered the enteric bacterium, Escherichia coli, to manipulate the levels of the interspecies quorum sensing signal, autoinducer-2 (AI-2), in the mouse intestine and investigated the effect upon antibiotic-induced gut microbiota dysbiosis. E. coli that increased intestinal AI-2 levels altered the composition of the antibiotic-treated gut microbiota, favoring the expansion of the Firmicutes phylum. This significantly increased the Firmicutes/Bacteroidetes ratio, to oppose the strong effect of the antibiotic, which had almost cleared the Firmicutes. This demonstrates that AI-2 levels influence the abundance of the major phyla of the gut microbiota, the balance of which is known to influence human health.

Light activation of photosensitizing dyes in presence of molecular oxygen generates highly cytotoxic reactive oxygen species leading to cell inactivation. Nucleic acids are molecular targets of this photodynamic action but not considered the main cause of cell death. The in vivo effect of the photodynamic process on the intracellular nucleic acid content of Escherichia coli and Staphylococcus warneri was evaluated herein. Two cationic porphyrins (Tetra-Py(+)-Me and Tri-Py(+)-Me-PF) were used to photoinactivate E. coli (5.0μM; 10(8)cellsmL(-1)) and S. warneri (0.5μM; 10(8)cellsmL(-1)) upon white light irradiation at 4.0mWcm(-2) for 270min and 40min, respectively. Total nucleic acids were extracted from photosensitized bacteria after different times of irradiation and analyzed by agarose gel electrophoresis. The double-stranded DNA was quantified by fluorimetry and the porphyrin binding to bacteria was determined by spectrofluorimetry. E. coli was completely photoinactivated with both porphyrins (5.0μM), whereas S. warneri was only completely inactivated by Tri-Py(+)-Me-PF (0.5μM). The hierarchy of nucleic acid changes in E. coli was in the order: 23S rRNA>16S rRNA>genomic DNA. The nucleic acids of S. warneri were extensively reduced after 5min with Tri-Py(+)-Me-PF but almost unchanged with Tetra-Py(+)-Me after 40min of irradiation. The amount of Tri-Py(+)-Me-PF bound to E. coli after washing the cells is higher than Tetra-Py(+)-Me and the opposite was observed for S. warneri. The binding capacity of the photosensitizers is not directly related to the PDI efficiency or nucleic acid reduction and this reduction occurs in parallel with the decrease of surviving cells., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objectives: To investigate the presence and the genetic environment of the multiresistance gene cfr in Jeotgalicoccus pinnipedialis and Macrococcus caseolyticus from pigs., Methods: A total of 391 bacterial isolates with florfenicol MICs ≥16 mg/L were obtained from nasal swabs of 557 individual pigs; of these, 75 Gram-positive isolates other than staphylococci and enterococci were screened by PCR for the presence of known florfenicol resistance genes. Species assignments of the cfr-carrying isolates were based on the results of biochemical profiling and 16S rDNA sequencing. The locations of the cfr gene were determined by Southern blotting. Regions flanking each cfr gene were sequenced by a modified random primer walking strategy, and the transferability of cfr was assessed by electrotransformation., Results: Two M. caseolyticus isolates and one J. pinnipedialis isolate were cfr positive. The cfr gene was located either on a 7057 bp plasmid, pSS-03, which was widely distributed among staphylococci of pig origin, or on the ∼53 kb plasmid pJP1. The region of pJP1 that included the cfr gene and the adjacent IS21-558, showed 99.7% identity to the corresponding region of plasmid pSCFS3. In addition, the genes aadD + aacA-aphD, ble and erm(C), coding for aminoglycoside, bleomycin and macrolide-lincosamide-streptogramin B resistance, respectively, were also identified on plasmid pJP1., Conclusions: This study showed that plasmids carrying the multidrug resistance gene cfr are present in two new genera of commensal and environmental bacteria, Macrococcus and Jeotgalicoccus. This observation underlines the role of commensal and environmental flora in the dissemination of clinically important resistance genes, such as cfr.

Modification of the ring nucleus of tetramic acids derived from serine gives chiral heterocyclic libraries that exhibit antibacterial activity, and correlation with various physicochemical parameters indicates that chiral tetramic acids may provide a potentially valuable non-aromatic skeleton for fragment-based drug discovery., (© 2011 John Wiley & Sons A/S.)

The validation of a microbiological assay applying the cylinder-plate method to determine the quinolone gemifloxacin mesylate (GFM) content is described. Using a strain of Staphylococcus epidermidis ATCC 12228 as the test organism, the GFM content in tablets at concentrations ranging from 0.5 to 4.5 μg mL(-1) could be determined. A standard curve was obtained by plotting three values derived from the diameters of the growth inhibition zone. A prospective validation showed that the method developed is linear (r=0.9966), precise (repeatability and intermediate precision), accurate (100.63%), specific and robust. GFM solutions (from the drug product) exposed to direct UVA radiation (352 nm), alkaline hydrolysis, acid hydrolysis, thermal stress, hydrogen peroxide causing oxidation, and a synthetic impurity were used to evaluate the specificity of the bioassay. The bioassay and the previously validated high performance liquid chromatographic (HPLC) method were compared using Student's t test, which indicated that there was no statistically significant difference between these two validated methods. These studies demonstrate the validity of the proposed bioassay, which allows reliable quantification of GFM in tablets and can be used as a useful alternative methodology for GFM analysis in stability studies and routine quality control. The GFM reference standard (RS), photodegraded GFM RS, and synthetic impurity samples were also studied in order to determine the preliminary in vitro cytotoxicity to peripheral blood mononuclear cells. The results indicated that the GFM RS and photodegraded GFM RS were potentially more cytotoxic than the synthetic impurity under the conditions of analysis applied., (Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.)

Macrococcus is a bacterial genus that is closely related to Staphylococcus, which typically is isolated from animal skin and products. The genome analysis of multidrug-resistant Macrococcus caseolyticus strain JCSC5402, isolated from chicken, previously led to the identification of plasmid pMCCL2, which carries a transposon containing an unusual form of the Macrococcus mec gene complex (mecA(m)-mecR1(m)-mecI(m)-blaZ(m)). In M. caseolyticus strain JCSC7096, this mec transposon containing the mec gene complex (designated Tn6045 in this study) was found integrated downstream of orfX on the chromosome. Tn6045 of JCSC7096 was bracketed by the direct repeat sequences (DR) specifically recognized by cassette chromosome recombinase (CCR). A non-mecA-containing staphylococcal cassette chromosome (SCC) element, designated SCC(7096), was integrated next to the mec transposon and separated from the latter by a DR. Nested PCR experiments showed that the mec transposon not only was excised singly but also coexcised with SCC(7096) from the chromosome at the DRs. The coexcised elements formed the extrachromosomal closed circular DNA of the SCCmec-like element. SCCmec is known to be the mobile element conveying methicillin (meticillin) resistance in staphylococci. However, its origin has been unknown. Our observation revealed a potential mechanism of the generation of a new SCCmec-like element in M. caseolyticus, a commensal bacterium of food animals.

Objective: This pilot study determined the profile of the oral bacterial flora in an outpatient cancer population before and after chemotherapy using molecular techniques., Study Design: We recruited 9 newly diagnosed breast cancer patients scheduled for induction chemotherapy. All were seen immediately before chemotherapy, and 7 to 14 days later. At both visits, we performed oral evaluations and obtained mucositis grading (with the World Health Organization [WHO] scale), absolute neutrophil counts (ANC), and bacterial samples from the buccal mucosa. Bacterial DNA was isolated, and 16S ribosomal RNA gene clonal libraries were constructed. Sequences of genes in the library were used to determine species identity by comparison to known sequences., Results: After chemotherapy, WHO scores of 0 and 1 were in 3 and 6 patients, respectively, and mean ANC (+/-SD) dropped from 3326 +/- 463 to 1091 +/- 1082 cells/mm(3). From pre- and post-chemotherapy samples, 41 species were detected, with a predominance of Gemella haemolysans and Streptococcus mitis. More than 85% of species have not been previously identified in chemotherapy patients. Seven species appeared exclusively before chemotherapy and 25 after chemotherapy. After chemotherapy, the number of species per patient increased by a mean of 2.6 (SD = 4.7, P = .052)., Conclusion: We identified species not previously identified in chemotherapy patients. Our results suggest a shift to a more complex oral bacterial profile in patients undergoing cancer chemotherapy., (Copyright 2010 Mosby, Inc. All rights reserved.)

A pathogen inactivation (PI) process has been developed using the frangible anchor linker effector (FRALE) compound S-303. A series of experiments were performed in whole blood (WB) to measure the level of viral and bacterial inactivation. The results showed that 0.2mM S-303 and 2mM glutathione (GSH) inactivated >6.5 logs of HIV, >5.7 logs of Bluetongue virus, >7.0 logs of Yersinia enterocolitica, 4.2 logs of Serratia marcescens, and 7.5 logs of Staphylococcus epidermidis. Recent development for S-303 is focused on optimization of the PI process for red blood cell concentrates (RBC). A series of studies in RBC showed that 0.2mM S-303 and 20mM GSH inactivated approximately 5 logs or greater of Y. enterocolitica, E. coli, S. marcescens, S. aureus, HIV, bovine viral diarrhoea virus, bluetongue virus and human adenovirus 5. In both applications of the S-303 process, in vitro parameters of RBC function and physiology were retained compared to conventional RBC. Results from these studies indicate that S-303 can be applicable for PI of RBC and WB., (Copyright 2009 The International Association for Biologicals. All rights reserved.)

Zanthoxylum tingoassuiba essential oil (EO) is a complex mixture of organic compounds among which methyl-N-methylanthranilate and sesquiterpene alcohol alpha-bisabolol represent the main compounds. The essential oil antimicrobial activity was studied against bacteria and fungi cells by diffusion disk method and significant activity was observed against S. aureus, S. aureus isolated multi-resistant and the dermathophyte fungi. Essential oil from Zanthoxylum tingoassuiba loaded into DPPC multilamellar liposomes (MLV) was successfully produced through a thin film hydration method with mean diameter of 9.37 +/- 4.69 microm. The EO-loaded liposomes showed adequate sphericity and narrower size distribution than empty liposomes. Results also showed that Zanthoxylum tingoassuiba essential oil can be incorporated in appreciable amounts (43.7 +/- 6.0%) in the prepared vesicular dispersions. A strong interaction between essential oil and lipid bilayer was indicated by a significant decrease in T(m) of the EO-loaded liposomes related to empty vesicles. Essential oil showed incomplete release profile from liposomes, suggesting that EO-loaded liposomes will be useful in pharmaceutical applications to enhance essential oil targeting to cells.

Aim: To assess the effects of cyclophosphamide (CP), methotrexate (MT), and prednisolone (PS) on the levels of staphylococci, enterococci, Escherichia coli (EC) and lactose-negative enterobacteria (LNEB) in feces of white mice as well as to determine adhesive properties of isolated microorganisms., Materials and Methods: Drugs were administered intragastrically during 6 weeks; CP in dose 35.4 mg/kg daily; MT - 2.5 mg/kg over week; PS - 2.5 mg/kg daily; sterile distilled water was administered to controls. Microflora was assessed by common methods; adhesion of microorganisms to group 0 (I) human erythrocytes was determined., Results: Administration of prednisolone leads to increase of isolation rate of staphylococci, CP increased levels of LNEB and EC with suppressed enzymatic activity (P < 0.05). MT decreased isolation rate of typical EC (P < 0.05). MT also decreased degree of adhesion of EC and LNEB, whereas PS enhanced adhesiveness of LNEB, and CP decreased adhesion of staphylococci (P < 0.05). Statistically significant correlation between number and adhesiveness of enterobacteria was established (r = 0.73, P < 0.01)., Conclusion: Immunodepressors from different groups have non-similar effects on quantitative characteristics of microflora and adhesiveness of isolated opportunistic microorganisms.

Hospital-acquired infections and antibiotic-resistant bacteria continue to be major health concerns worldwide. Particularly problematic is methicillin-resistant Staphylococcus aureus (MRSA) and its ability to cause severe soft tissue, bone or implant infections. First used by the Australian Aborigines, Tea tree oil and Eucalyptus oil (and several other essential oils) have each demonstrated promising efficacy against several bacteria and have been used clinically against multi-resistant strains. Several common and hospital-acquired bacterial and yeast isolates (6 Staphylococcus strains including MRSA, 4 Streptococcus strains and 3 Candida strains including Candida krusei) were tested for their susceptibility for Eucalyptus, Tea tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea and Sage oil with the agar diffusion test. Olive oil, Paraffin oil, Ethanol (70%), Povidone iodine, Chlorhexidine and hydrogen peroxide (H(2)O(2)) served as controls. Large prevailing effective zones of inhibition were observed for Thyme white, Lemon, Lemongrass and Cinnamon oil. The other oils also showed considerable efficacy. Remarkably, almost all tested oils demonstrated efficacy against hospital-acquired isolates and reference strains, whereas Olive and Paraffin oil from the control group produced no inhibition. As proven in vitro, essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species.

Antibiotic susceptibility against 19 antimicrobial agents was evaluated in isolates of the genera Lactococcus (46 isolates), Leuconostoc (22), Lactobacillus (19), Staphylococcus (8), Enterococcus (7), and Microccoccus/Kocuria (5) obtained from the predominant microflora of nonrecent and recent types of artisanal raw cow's milk cheeses. Beta-lactams showed broad activity against all genera, although leuconostocs and lactobacilli were highly resistant to oxacillin (80% to 95.5%). Resistance to aminoglycosides was frequent for lactococci and enterococci (particularly for streptomycin), whereas lower rates of resistance were detected for lactobacilli and leuconostocs. Technologically interesting traits for the food industry were distributed among isolates that showed different degrees of resistance to common antibiotics. However, isolates showing resistance to less than 2 antibiotics were mainly those with properties of greatest technological interest (acidifying activity, proteolytic/lipolytic activities, or diacetyl production).

We isolated the methicillin-resistant Macrococcus caseolyticus strain JCSC5402 from animal meat in a supermarket and determined its whole-genome nucleotide sequence. This is the first report on the genome analysis of a macrococcal species that is evolutionarily closely related to the human pathogens Staphylococcus aureus and Bacillus anthracis. The essential biological pathways of M. caseolyticus are similar to those of staphylococci. However, the species has a small chromosome (2.1 MB) and lacks many sugar and amino acid metabolism pathways and a plethora of virulence genes that are present in S. aureus. On the other hand, M. caseolyticus possesses a series of oxidative phosphorylation machineries that are closely related to those in the family Bacillaceae. We also discovered a probable primordial form of a Macrococcus methicillin resistance gene complex, mecIRAm, on one of the eight plasmids harbored by the M. caseolyticus strain. This is the first finding of a plasmid-encoding methicillin resistance gene. Macrococcus is considered to reflect the genome of ancestral bacteria before the speciation of staphylococcal species and may be closely associated with the origin of the methicillin resistance gene complex of the notorious human pathogen methicillin-resistant S. aureus.

This study investigated slime production by coagulase-negative staphylococci (CNS) using the standard tube (ST), Congo red agar (CRA) plate and Christensen's tube (CT) methods, and compared the results with those of the crystal violet reaction (CVR) test. The potential correlation between slime production and antimicrobial resistance was also evaluated. In total, 205 CNS strains were isolated from biological samples: 92 (44.9%) were shown to produce slime by the ST method; 96 (46.8%) by the CRA plate method; 90 (43.9%) by the CT method; and 89 (43.4%) strains were CVR positive. Eighty-three (40.5%) CNS strains were positive for slime production by the ST, CRA and CT methods. The findings of the ST, CRA and CT test methods were consistent with each other but were not related to CVR positivity. Based on the ST method, rates of antibiotic resistance to several antimicrobial agents were higher in slime-positive strains than in slime-negative strains and, in some cases, this was statistically significant.

Poly(methyl methacrylate) (PMMA) nanofiber containing silver nanoparticles was synthesized by radical-mediated dispersion polymerization and applied to an antibacterial agent. UV-vis spectroscopic analysis indicated that the silver nanoparticles were continually released from the polymer nanofiber in aqueous solution. The antibacterial properties of silver/PMMA nanofiber against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria were evaluated using minimum inhibitory concentration (MIC), the modified Kirby-Bauer method, and a kinetic test. The MIC test demonstrated that the silver/PMMA nanofiber had enhanced antimicrobial efficacy compared to that of silver sulfadiazine and silver nitrate at the same silver concentration.

Objective: Susceptibility to seven betalactam antibiotics, glycopeptides and aminoglycosides was investigated in 190 erythromycin-resistant alpha-hemolytic streptococci and 30 Gemella spp, mainly from normal flora., Material and Methods: Antimicrobial susceptibility testing was performed by a standard agar diffusion test and a standard agar dilution method according to NCCLS/CLSI criteria., Results: 62.6% of alfahemolytic streptococci and 53.3% of Gemella spp. were not susceptible to penicillin (MIC50: 0,5 microg/mL). Cefuroxime was the least active cephalosporin (MIC50: 1 microg/mL and 0.5 microg/mL, in streptococci and Gemella spp., respectively), whereas cefotaxime, ceftriaxone (MIC50: 0.25 microg/mL) and cefepime (MIC50: 0.5 microg/mL) were more active than penicillin. All isolates were susceptible to vancomycin, teicoplanin and gentamicin. Four alfahemolytic streptococcal strains showed high-level resistance to streptomycin, and three strains to kanamycin. There were no significant differences in resistance rates to the antibiotics studied between strains with different macrolide resistance phenotypes. Resistance to penicillin and other betalactam antibiotics (73.8%) was prevalent in M phenotype strains and resistance to penicillin and other classes of antibiotics predominated in constitutive (cMLS(B)) strains (71.4%)., Conclusions: Resistance to penicillin in erythromycin-resistant strains was notably high in this study. This fact has important clinical implications because of the endogenous character of alpha-hemolytic streptococcal and Gemella spp. infections. The lower cefuroxime activity suggests that use of this agent against other pathogens would be effective in preserving the oropharyngeal microflora analyzed.

Percutaneous devices are extensively used in modern medicine therapies, even in long term applications. Complications from their use, related to bacterial colonization and/or to materials thrombogenicity, may result in a significant morbidity and mortality incidence. In this study, a novel polycarbonate-urethane (PCU), incorporating a tailor-made diamino-diamide-diol (PIME) showing the ability to bind heparin at physiological pH, was compared to commercial medical-grade PCUs (Carbothane and Bionate). Mechanical and thermal properties were evaluated by tensile tests, dynamic mechanical analysis and differential scanning calorimetry. The presence of a low amount of PIME chain extender in Bionate polyurethanes (Bionate-PIME) slightly affects the mechanical properties, remaining however comparable with the medical grade PCUs used for the fabrication of cardiovascular devices. To verify thereof heparin surface adsorbed in disfavouring bacterial colonization, heparinized Bionate-PIME was tested for bacterial adhesion, using Bionate and Carbothane as reference. In vitro bacterial interaction tests were performed with the strains mainly involved in the pathogenesis of device-related infections (S. epidermidis and S. aureus). MTT tests and SEM observations showed a decrease in colonization of the different strains on the heparinized Bionate-PIME surfaces, confirming that preadsorbed heparin plays a role in mediating the biomaterial surface/bacterial cells interactions.

Purpose: To report a novel case of infectious crystalline keratopathy after penetrating keratoplasty caused by Gemella haemolysans., Methods: Observational case report. Patient notes and literature review., Results: A 51-year-old woman presented with the clinical picture of infectious crystalline keratopathy 18 months after a second penetrating keratoplasty was performed for corneal decompensation secondary to recurrent herpes simplex infection. Corneal biopsy yielded a heavy growth of G. haemolysans. Initial treatment was made up of frequent topical vancomycin 0.5% and was later changed to topical cefuroxime 5% and ofloxacin 0.3%. Snellen visual acuity after complete resolution of the keratitis was 6/60 as a result of a residual corneal scar., Conclusions: Gemella haemolysans may be an etiologic agent in infectious crystalline keratopathy. A corneal biopsy may be diagnostic but may also promote healing by allowing direct access of antibiotics to deep-seated infected tissue and by altering the growth environment of the organism.

The epidemiologic relatedness of 29 erythromycin-resistant Gemella sp. strains from normal flora, characterized previously, were evaluated by pulsed-field gel electrophoresis (PFGE). Three isolates carried the tet(O) gene and the tet(M) gene. The msr(A) gene was found in two Gemella morbillorum strains in combination with the erm(B) or mef(E) gene. The sequences of the mef(A/E), erm(B), and msr(A) genes showed a high similarity to the corresponding sequences of other gram-positive cocci. All the strains harboring the mef(A/E) gene and the msr(D) gene possessed open reading frame 3 (ORF3)/ORF6. The 16 G. morbillorum isolates represented 15 distinct DNA profiles. Four clusters were identified (>or=80% genetic relatedness). The 12 Gemella haemolysans strains belonged to different PFGE types. The clonal diversity found suggests that horizontal transfer may be the main route through which erythromycin resistance is acquired.

Pseudomonas aeruginosa and Staphylococcus aureus are opportunistic pathogens and frequently coinfect the lungs of cystic fibrosis patients. P. aeruginosa secretes an arsenal of small respiratory inhibitors, like pyocyanin, hydrogen cyanide, or quinoline N-oxides, that may act against the commensal flora as well as host cells. Here, we show that with respect to their susceptibility to these respiratory inhibitors, staphylococcal species can be divided into two groups: the sensitive group, comprised of pathogenic species such as S. aureus and S. epidermidis, and the resistant group, represented by nonpathogenic species such as S. carnosus, S. piscifermentans, and S. gallinarum. The resistance in the latter group of species was due to cydAB genes that encode a pyocyanin- and cyanide-insensitive cytochrome bd quinol oxidase. By exchanging cydB in S. aureus with the S. carnosus-specific cydB, we could demonstrate that CydB determines resistance. The resistant or sensitive phenotype was based on structural alterations in CydB, which is part of CydAB, the cytochrome bd quinol oxidase. CydB represents a prime example of both microevolution and the asymmetric pattern of evolutionary change.

Bacteremias in inpatient chronic HD units have been described, but there is little information on bacteremias in ambulatory HD units. To determine the frequency of bacteremia and pathogen distribution in ambulatory chronic HD units, we retrospectively reviewed our experience with 107 bacteremias in 5 chronic ambulatory HD units over a 3 year period. The object of the study was twofold. The first objective was to determine if bacteremias in ambulatory HD setting were substantially different in frequency or type than in the inpatient HD setting. Secondly, febrile patients suspected of having bacteremia in chronic HD patients are often empirically treated with vancomycin and gentamicin. Chronic HD patients require repeated and frequent venous access for HD. Bacteremias are common in chronic HD patients and may be primary or secondary and are often related to venous access site infections. The distributions of bacteremia pathogens in chronic HD patients are predominantly reflective of skin flora, i.e., staphylococci and to lesser extent aerobic Gram-negative bacilli. After S. aureus (MSRA/MSSA) and coagulase-negative staphylococcus (CoNS), enterococci are the next most important Gram-positive pathogens in bacteremic HD patients. Most strains of E. faecalis are sensitive to vancomycin and for practical purposes should be considered as vancomycin sensitive enterococci (VSE). In contrast, most strains of E. faecium are resistant to vancomycin and should be considered as vancomycin resistant enterococci (VRE). We retrospectively reviewed 107 patients on chronic ambulatory HD to determine the adequacy of empiric vancomycin and gentamicin prophylaxis. We found amikacin is preferred to gentamicin and that meropenem is an effective alternate substitution for gentamicin and vancomycin combination therapy.

Two rare cases of Gemella morbillorum endocarditis, caused by a strain resistant to penicillin and gentamicin are reported. G. morbillorum is usually sensitive to beta-lactams and aminoglycosides. The present 2 cases raise concern that appropriate prophylaxis and empirical treatment may be more complicated than believed in the past.

A total of 50 healthy persons and 50 chronic tonsillitis patients were examined with the use of the bacteriological method. The microflora of tonsillar mucous membrane was represented by 8 genera of facultative anaerobic microorganisms. In the biocenosis of the tonsillar mucosa of the healthy subjects the occurrence of Streptococcus was 1.5-fold greater than in that of the patients; microorganisms of the genus Staphylococcus prevailed on the tonsillar mucosa of chronic tonsillitis patients 1.3-fold prevailed more often and Klebsiella and Neisseria prevailed 4-fold more often. Among the microorganisms isolated from the patients, cultures simultaneously having two or more pathogenicity markers occurred twice as often as among the representatives of the microbiocenosis obtained from the healthy subjects. The microflora of the tonsillar mucosa of the chronic tonsillitis patients was characterized by resistance to penicillins, macrolides and aminoglygosides, but was simultaneously sensitive to lincosamides and glycopeptides.

The reactions of [RuHCl(CO)(PPh3)2(B)] (B = PPh3, pyridine or piperidine) and 2'-hydroxychalcones led to the formation of [RuCl(CO)(PPh3)(L)(B)] (L = chalconate). The new complexes have been characterized by analytical and spectral (IR, electronic, 1H NMR and 31P NMR) data. They have been assigned an octahedral structure. The complexes have been used as catalysts for the aerial oxidation of cinnamyl alcohol. Some of the complexes have been tested in vitro for growth inhibitory activity against the bacteria E. coli, S. typhi and Pseudomonas sp. and the fungi A. fumigatus.

We assessed the mechanisms of resistance to macrolide-lincosamide-streptogramin B (MLS(B)) antibiotics and related antibiotics in erythromycin-resistant viridans group streptococci (n = 164) and Gemella spp. (n = 28). The macrolide resistance phenotype was predominant (59.38%); all isolates with this phenotype carried the mef(A) or mef(E) gene, with mef(E) being predominant (95.36%). The erm(B) gene was always detected in strains with constitutive and inducible MLS(B) resistance and was combined with the mef(A/E) gene in 47.44% of isolates. None of the isolates carried the erm(A) subclass erm(TR), erm(A), or erm(C) genes. The mel gene was detected in all but four strains carrying the mef(A/E) gene. The tet(M) gene was found in 86.90% of tetracycline-resistant isolates and was strongly associated with the presence of the erm(B) gene. The cat(pC194) gene was detected in seven chloramphenicol-resistant Streptococcus mitis isolates, and the aph(3')-III gene was detected in four viridans group streptococcal isolates with high-level kanamycin resistance. The intTn gene was found in all isolates with the erm(B), tet(M), aph(3')-III, and cat(pC194) gene. The mef(E) and mel genes were successfully transferred from both groups of bacteria to Streptococcus pneumoniae R6 by transformation. Viridans group streptococci and Gemella spp. seem to be important reservoirs of resistance genes.

Among nine patients with bacteremia caused by Granulicatella or Gemella in a 6-year period (July 1995 to June 2001), three had bacteremia caused by erythromycin-resistant Granulicatella adiacens and one had bacteremia caused by erythromycin-resistant Gemella haemolysans. All four isolates possessed mef genes, whereas none possessed ermT, ermTR, or ermB genes.

In this study, we report the design, synthesis and structure-activity relationships of novel indazole derivatives as DNA gyrase inhibitors with Gram-positive antibacterial activity. Our results show that selected compounds from this series exhibit potent antibacterial activity against Gram-positive bacteria including multi-drug resistant strains that is methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE).

In this study, we designed and synthesized novel 5-vinylpyrazole analogues by decreasing the lipophilicity of the parent compounds 1a,b; 3-[(3-methoxycarbonyl)cyclohexylaminomethyl]indazoles while keeping the van der Waals interaction with the lipophilic area of DNA gyrase B. The selected compound 8bb exhibited good antibacterial activity against staphylococci and enterococci, including multi-drug resistant strains.

One hundred and sixty viridans group streptococci (VGS) and 26 Gemella spp. resistant to erythromycin were studied to detect macrolide lincosamide and streptogramin B (MLS(B)) phenotypes and to investigate resistance rates to other antibiotics. The M phenotype was most prevalent in both bacterial groups (59.6% in VGS, 69.2% in gemellae) and the iMLS(B) phenotype was found least often (9.3 and 13.9%, respectively). All isolates with M phenotype had the mef(A/E) gene, being prevalent the mef(E) subclass. cMLS(B) and iMLS(B) strains contained the erm(B) gene, alone or in combination with the mef(A/E) gene. Thirteen isolates were intermediately resistant to quinupristin/dalfopristin and 11 strains showed low susceptibility to telithromycin. Linezolid was active against all the isolates tested and tetracycline resistance was the major one in VGS (41.6%) and Gemella spp. (46.2%)., (Copyright 2004 Elsevier B.V.)

Endogenous antimicrobial peptides are ubiquitous components of animal and plant host defences. These peptides, usually cationic and amphipathic, kill target cells rapidly and are efficacious against antibiotic-resistant and clinically relevant pathogens. A practical challenge in the development of cationic peptides as therapeutics is to meet the production requirements for large quantities of highly purified drug substance at competitive costs. While chemical peptide synthesis can be used to manufacture cationic peptides, we have developed cost-effective methods for recombinant production by expressing fusion proteins comprised of multiple copies of the peptides. The fusion proteins accumulate in Escherichia coli inclusion bodies and constitute over 50% of the total cellular proteins. Active antimicrobial peptides are released by chemical reagents and purified by chromatography, combining both standard and novel approaches. Challenges of industrial-scale manufacturing of therapeutics were considered in the development of this process.