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Background and aim Wound infection constitutes a major barrier to healing and can have a harmful effect on the patient's quality of life and also on the healing rate of the wound. The widespread use of antibiotics, along with their extensive history of availability, has resulted in significant issues with resistant organisms contributing to morbidity and mortality. The study was conducted to determine the prevalence of bacterial species obtained from the wound sample and its antibiotic resistance pattern. Materials and methods The cross-sectional observational study was conducted from November 2022 to November 2023 in a tertiary care hospital in Karad. 100 clinical samples of wound swabs and pus were studied. The isolates from these clinical samples were further processed as per the standard prescribed for the identification and antimicrobial susceptibility testing. Results  Out of 100 isolates, 75 were gram-negative and 25 gram-positive. Among the gram-negative isolates, the predominantly isolated organism was  Klebsiella  spp. 20(26.66%), and gram-positive bacteria was mainly Staphylococcus aureus  (23, 92%). Most of the isolates showed sensitivity to vancomycin (20, 86.95%) and resistance to penicillin (18, 78.26%).  Klebsiella  spp. (20, 26.66%) was mostly sensitive to piperacillin/tazobactam (7, 50%), and resistance was seen to ampicillin (12, 85.71%). Conclusion This study showed that Staphylococcus aureus was the most common bacterial isolate causing wound infection, followed by Klebsiella spp. Antimicrobial susceptibility test showed that vancomycin was effective, followed by tetracycline for Staphylococcus aureus and piperacillin/tazobactam, and tigecycline was effective for Klebsiella spp., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Institutional Ethics Committee Krishna Vishwa Vidyapeeth Deemed to be University, Karad issued approval 066/2021-2022. The Institutional Ethics Committee has hereby given permission to initiate the research project (Protocol Number 066/2021-2022). Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Bhujugade et al.)

Background: The emergence and spread of β-lactamase-producing Klebsiella spp. has been associated with a substantial healthcare burden resulting in therapeutic failures. We sought to describe the proportion of phenotypic resistance to commonly used antibiotics, characterize β-lactamase genes among isolates with antimicrobial resistance (AMR), and assess the correlates of phenotypic AMR in Klebsiella spp. isolated from stool or rectal swab samples collected from children being discharged from hospital., Methods: We conducted a cross-sectional study involving 245 children aged 1-59 months who were being discharged from hospitals in western Kenya between June 2016 and November 2019. Whole stool or rectal swab samples were collected and Klebsiella spp. isolated by standard microbiological culture. β-lactamase genes were detected by PCR whilst phenotypic antimicrobial susceptibility was determined using the disc diffusion technique following standard microbiology protocols. Descriptive analyses were used to characterize phenotypic AMR and carriage of β-lactamase-producing genes. The modified Poisson regression models were used to assess correlates of phenotypic beta-lactam resistance., Results: The prevalence of β-lactamase carriage among Klebsiella spp. isolates at hospital discharge was 62.9% (154/245). Antibiotic use during hospitalization (adjusted prevalence ratio [aPR] = 4.51; 95%CI: 1.79-11.4, p < 0.001), longer duration of hospitalization (aPR = 1.42; 95%CI: 1.14-1.77, p < 0.002), and access to treated water (aPR = 1.38; 95%CI: 1.12-1.71, p < 0.003), were significant predictors of phenotypically determined β-lactamase. All the 154 β-lactamase-producing Klebsiella spp. isolates had at least one genetic marker of β-lactam/third-generation cephalosporin resistance. The most prevalent genes were bla CTX-M 142/154 (92.2%,) and bla SHV 142/154 (92.2%,) followed by bla TEM 88/154 (57.1%,) and bla OXA 48/154 (31.2%,) respectively., Conclusion: Carriage of β-lactamase producing Klebsiella spp. in stool is common among children discharged from hospital in western Kenya and is associated with longer duration of hospitalization, antibiotic use, and access to treated water. The findings emphasize the need for continued monitoring of antimicrobial susceptibility patterns to inform the development and implementation of appropriate treatment guidelines. In addition, we recommend measures beyond antimicrobial stewardship and infection control within hospitals, improved sanitation, and access to safe drinking water to mitigate the spread of β-lactamase-producing Klebsiella pathogens in these and similar settings., (© 2024. The Author(s).)

Background: The increasing spread of fluoroquinolone resistant enteric bacteria is a global public health concern. Children recently discharged from the hospital are at high risk of carriage of antimicrobial resistance (AMR) due to frequent exposure to antimicrobials during inpatient stays. This study aimed to determine the prevalence, correlates of ciprofloxacin (CIP) non-susceptibility, and distribution of plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli (E. coli) and Klebsiella spp isolated from children under five years being discharged from two Kenyan Hospitals., Methods: E. coli and Klebsiella spp were isolated from fecal samples from children discharged from hospital and subjected to antimicrobial susceptibility testing (AST) by disc diffusion and E-test. CIP non-susceptible isolates were screened for seven PMQR genes using multiplex polymerase chain reaction (PCR). Poisson regression was used to determine the association between the carriage of CIP non-susceptible isolates and patient characteristics., Results: Of the 280 CIP non-susceptible isolates: 188 E. coli and 92 Klebsiella spp isolates identified among 266 discharged children, 195 (68%) were CIP-non-susceptible with minimum inhibitory concentrations (MICs) of ≥ 1 µg/mL. Among these 195 isolates, 130 (67%) had high-level CIP MIC =  ≥ 32 µg/mL). Over 80% of the isolates had at least one PMQR gene identified: aac(6')lb-cr (60%), qnrB (24%), oqxAB (22%), qnrS (16%), and qepA (6%), however, qnrA was not identified in any isolates tested. Co-carriage of qnrB with acc(6')-lb-cr was the most predominant accounting for 20% of all the isolates. Ceftriaxone use during hospital admission and the presence of extended spectrum beta-lactamase (ESBL) production were significantly associated with the carriage of CIP non-susceptible E. coli and Klebsiella spp., Conclusion: CIP non-susceptibility is common among E. coli and Klebsiella spp isolated from hospital discharged children in Kenya. Carriage and co-carriage of PMQR, including the newly identified qepA gene, were frequently observed. These findings suggest that children leaving the hospital may serve as an important reservoir for transmission of resistant E. coli and Klebsiella spp to the community. Enhanced surveillance for AMR determinants is critical to inform interventions to control antimicrobial-resistant bacteria., (© 2023. The Author(s).)

Background: Antimicrobial resistance among gram-negative bacteria has been growing, particularly in developing countries, like Iran. The emergence and spread of carbapenem-resistance mechanisms is a major public health concern because no definite treatments have yet been established for this problem. This study aimed to evaluate antibiotic susceptibility of gram-negative bacteria, metallo-β-lactamases (MBLs) and carbapenemase-producing genes, including bla NDM , bla VIM , and bla IMP in patients referred to Children's Medical Center, Tehran, Iran., Material and Methods: In this cross-sectional study, a total of 944 gram-negative isolates were tested in the study, and antimicrobial susceptibility testing was performed. Moreover, MBL production of carbapenem-resistant isolates, as well as the presence of bla NDM , bla VIM , and bla IMP , was investigated., Results: The most common gram-negative isolated bacteria were Escherichia coli (489 samples, 52%), followed by Klebsiella pneumoniae (167 samples, 18%), Pseudomonas aeruginosa (101 samples, 11%), Enterobacter spp. (64 samples, 7%), Pseudomonas spp. (35 samples, 4%), Acinetobacter baumannii (18 samples, 2%), and Burkholderia cepacia (17 samples, 2%). Imipenemresistant was found in 75%, 61%, and 60% of Stenotrophomonas maltophilia, Enterobacter spp., and A. baumannii isolates, respectively. Moreover, the highest resistance to meropenem was observed in S. maltophilia, A. baumannii, P. aeruginosa, and B. cepacia (100%, 96%, 83%, and 61.5%, respectively). Double disk synergy test (DDST) results showed that 112 out of 255 carbapenem- resistant isolates (44%) were MBL-producing ones. The presence of the bla NDM gene was identified in 32 (29%) of MBL-producing isolates, 13 of which were K. pneumoniae, 7 P. aeruginosa, and 7 E. coli, 3 Enterobacter spp., and 2 Klebsiella spp., respectively. The presence of the bla IMP and bla VIM genes was detected in 2 (2%) and 1 (1%) of MBL-producing isolates. These genes were detected in only MBL-producing P. aeruginosa isolates., Conclusion: Our findings suggest the emergence of NDM-producing strains in our hospital, and bla NDM was the most frequently detected carbapenemase gene in MBL-producing P. aeruginosa, K. pneumoniae, and Klebsiella spp. Since such bacteria can easily spread among patients in the hospital, a strong infection control and prevention plan is highly recommended., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objectives: This study aimed to characterize Gram negative bacteria carrying bla GES carbapenemase genes detected in wastewater from a hospital with no history of detection of clinical isolates producing GES carbapenemases., Methods: Six hospital effluent samples were screened for carbapenemase-producing organisms (CPO) using CHROMagar mSuperCARBA and MacConkey agar with 1 µg/mL imipenem. Polymerase chain reaction (PCR) amplification and sequencing of carbapenemase genes, multilocus sequence typing, antimicrobial susceptibility testing, and whole-genome sequencing were performed., Results: Among 21 CPO isolates, 11 Klebsiella spp. and 5 Enterobacter kobei isolates carried bla GES-24 , and 4 E. roggenkampii and 1 Pseudomonas aeruginosa isolates carried bla GES-5 . Genomic analysis of 8 representative isolates comprising 6 bla GES-24 -positive and 2 bla GES-5 -positive revealed that class 3 integrons with complete or defective Tn402-like transposition modules were predominantly associated with two tandem copies of bla GES-24 . Furthermore, a total of 5 new class 3 integrons, In3-18 to In3-22, were identified among 5 bla GES-24 and 1 bla GES-5 plasmids. One strain each of K. pneumoniae subsp. pneumoniae and K. quasipneumoniae subsp. similipneumoniae harboring bla GES-24 plasmids also carried a rare bla VEB-1 -positive class 1 integron on a non-typeable plasmid, where these bla VEB-1 plasmids had high sequence similarity. Virulence gene profiles differed between Klebsiella spp. and Enterobacter spp.; the former harbored type III fimbriae cluster, salmochelin, and T6SS type i2 gene clusters, while the latter had curli pili operon, aerobactin, T2SS gene clusters, and T6SS type i3 gene clusters., Conclusion: Our findings confirmed the linkage of bla GES-24 with rare Tn402-like class 3 integrons and the structural diversity of their gene cassette arrays., Competing Interests: Competing interests None declared, (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The feasibility of employing the biological activated carbon (BAC) process to debilitate azo dye Carmoisine by Klebsiella spp. was investigated. Plate assay revealed the capability of Klebsiella spp. for removal of Carmoisine via degradation. Kinetic parameters were measured for Carmoisine debilitation by Klebsiella spp. using the suspended anaerobic process. Two types of granular and rod-shaped activated carbon were used to form the biological beds in order to study the Carmoisine debilitation in batch processes. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to indicate the colonization and biofilm formation of bacteria grown on activated carbon particles (ACPs). Thin-layer chromatography (TLC), liquid chromatography-mass spectrometry (LC-MS), high-pressure liquid chromatography (HPLC) and biosorption studies demonstrated biotransformation of Carmoisine into its constituent aromatic amines during the Carmoisine debilitation in suspended anaerobic and BAC processes. The porosity of activated carbons, inoculation size and age of biological beds were the important factors affecting the viability of bacterial cells grown on ACPs and, consequently, the rate and efficiency of the Carmoisine debilitation process determined through spectrophotometry. The reusability of biological beds was demonstrated by conducting sequential batch experiments. In conclusion, the BAC process proved to be an efficient method for anaerobic dye degradation.

We optimized and prospectively evaluated a simple MALDI-TOF MS-based method for direct detection of third-generation oxymino-cephalosporin resistance (3rd CephR) in Escherichia coli and Klebsiella spp. from blood cultures (BC). In addition, we assessed the performance of a lateral flow immunochromatographic assay (LFIC) for detecting extended-spectrum β-lactamases (ESBL) (NG-Test CTX-M MULTI assay) using bacterial pellets from BC. A total of 168 BCs from unique patients were included. A pre-established volume of BC flagged as positive was transferred in brain heart infusion with or without ceftriaxone (2 mg/ml). After 2-h incubation, intact bacterial pellets were used for MALDI-TOF MS testing. Identification of bacterial species (index score > 2) in the presence of CRO was considered marker of 3rd CephR. The LFIC assay was evaluated in 141 BC. Bacteremia episodes were caused by E. coli (n = 115) or Klebsiella spp. (n = 53). A total of 49 strains were 3rd CephR by broth microdilution, of which 41 were ESBL producers, seven expressed ESBL and OXA-48 type D carbapenemase, and one harbored a plasmid-mediated AmpC. The MALDI-TOF MS method yielded four very major errors (false susceptibility) and two major errors (false resistance). The overall sensitivity of the assay was 91.8% and the specificity 98.3%. Concordance between the LFIC assay and the MALDI-TOF MS method for detection of ESBL-mediated 3rd CephR was 100%. Both evaluated methods may prove useful for early adjustment of empirical therapy in patients with E. coli and Klebsiella spp. bloodstream infections. Whether their use has a beneficial impact on patient outcomes is currently under investigation., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Extended Spectrum Beta Lactamase (ESBL) production in gram negative bacteria confers multiple antibiotic resistance, adversely affecting antimicrobial therapy in infected individuals. ESBLs result from mutations in β-lactamases encoded mainly by the bla TEM ,bla SHV and bla CTX-M genes. The prevalence of ESBL producing bacteria has been on the increase globally, especially its upsurge among isolates from community-acquired infections has been observed., Aim: To determine ESBL prevalence and identify ESBL genes among clinical isolates in Osun State, Nigeria., Material and Methods: A cross-sectional study was carried out from August 2016 - July 2017 in Osun State, Nigeria. Three hundred and sixty Gram-negative bacteria recovered from clinical samples obtained from both community and healthcare-associated infections were tested. They included 147 Escherichia coli (40.8%), 116 Klebsiella spp (32.2%), 44 Pseudomonas aeruginosa (12.2%) and 23 Proteus vulgaris (6.4%) isolates. Others were Acinetobacter baumannii, Serratia rubidae, Citrobacter spp, Enterobacter spp and Salmonella typhi. Disk diffusion antibiotic susceptibility testing was carried out, isolates were screened for ESBL production and confirmed using standard laboratory procedures. ESBLs resistance genes were identified by Polymerase Chain Reaction (PCR)., Results: All isolates demonstrated multiple antibiotic resistance. Resistance to ampicillin, amoxicillin with clavulanate and erythromycin was 100%, whereas resistance to Imipenem was very low (5.0%). The overall prevalence of ESBL producers was 41.4% with Klebsiella spp as the highest ESBL producing Enterobacteriacaea. ESBL producers were more prevalent among the hospital pathogens than community pathogens, 58% vs. 29.5% (p=0.003). ESBL genes were detected in all ESBL producers with the bla CTX-M gene predominating (47.0%) followed by bla TEM (30.9%) and bla SHV gene was the least, 22.1%. The bla CTX-M gene was also the most prevalent in the healthcare pathogens (62%) but it accounted for only 25% in those of community origin., Conclusion: A high prevalence of ESBL producing gram-negative organisms occurs both in healthcare and in the community in our environment with the CTX-M variant predominating. Efforts to control the spread of these pathogens should be addressed., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objective: The production of β-lactamase enzymes such as AmpC β-lactamases and extended-spectrum β-lactamases (ESBLs) is among the main mechanisms for resistance to expanded-spectrum cephalosporins. The present study was conducted to investigate the prevalence and molecular epidemiology of plasmid-mediated AmpC beta (β)-lactamase in ESBL co-producing Escherichia coli (E. coli) and Klebsiella spp. (Klebsiella pneumoniae and Klebsiella oxytoca) clinical isolates in the northeast of Iran., Methods: A total of 602 E. coli and Klebsiella spp. clinical isolates were collected from three hospitals in Mashhad (northeast of Iran). A combination disk test (CDT) was performed for the phenotypic detection of ESBLs. Screening for the detection of AmpC β-lactamases was performed by a susceptibility test to a cefoxitin disc among ESBL producing isolates. A confirmatory test for AmpC β-lactamases was performed using the Mast® D68C test. Identification of plasmid-mediated AmpC cluster genes was done by multiplex polymerase chain reaction (PCR)., Results: Among 336 ESBL-producing strains, 230 (68.4%) isolates were resistant to cefoxitin. Results of the Mast® D68C test showed that 30% (69/230) of cefoxitin-resistant isolates simultaneously exhibited ESBL and AmpC activity and 22% (51/230) of isolates probably showed multi-drug resistant (MDR) phenotype. Results of multiplex PCR among ESBL-positive isolates showed that, 16.7% (56/336) of isolates were positive for plasmid-borneampC cluster genes, and CMY (38%) was the most frequent genotype of plasmid mediated AmpC., Conclusion: Findings of the study revealed that an increase in the prevalence of ESBL and AmpC co-producer in E. coli and Klebsiella spp. strains may become an important public health issue. Therefore, there is a vital need for surveillance of spread of these clinical isolates., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Biofilm formation in a dairy waste irrigation system can reduce treatment capacity and increase maintenance and cleaning. An extreme biofilm observed in a primary treated dairy wastewater system blocked the irrigation line requiring manual cleaning. Both next-generation genomic sequencing and the culturable fraction showed the presence of predominantly Gram-negative bacteria. Isolates identified from current samples and stored samples from the extreme biofilm included Pseudomonas, Citrobacter, Klebsiella and Enterobacter, one Gram-positive spore former (Bacillus cereus) and one unique isolate from the biofilm, a member of the Raoultella genus. Raoultella spp was only cultured from the extreme biofilm; however, next-generation sequencing analysis of a wastewater sample showed this bacterium to be present in the wastewater system. The dominance of Gram negative may be due to the wastewater from the washing equipment used to handle raw milk. Six bacteria from the fresh samples were found to be strong biofilm formers along with the Raoultella spp from the extreme biofilm. Tests using multiple isolates showed Raoultella spp to be important in biofilm formation. This is the first report of the microbial composition of a dairy wastewater biofilm giving insight into the population and growth of microorganisms in the sections of a dairy wastewater irrigation system.

Introduction: Cross-linked hyaluronic acid (HA) gel is widely used in esthetic medicine. Late bacterial infection (LBI) is a rare, but severe complication after HA augmentation. The aim of this study was to determine whether patients who underwent the HA injection procedure and developed LBI had qualitatively different bacterial flora on the skin compared to patients who underwent the procedure without any complications., Methods: The study group comprised 10 previously healthy women with recently diagnosed, untreated LBI after HA augmentation. The control group comprised 17 healthy women who had a similar amount of HA injected with no complications. To assess the difference between the two groups, their skin flora was cultured from nasal swabs, both before and after antibiotic treatment in the study group., Results: A significant increase in the incidence of Staphylococcus epidermidis was detected in the control group ( P =0.000) compared to the study group. The study group showed a significantly higher incidence of Staphylococcus aureus ( P =0.005), Klebsiella pneumoniae ( P =0.006), Klebsiella oxytoca ( P =0.048), and Staphylococcus haemolyticus ( P =0.048) compared to the control group., Conclusion: The bacterial flora on the skin differed in patients with LBI from the control group. The control group's bacterial skin flora was dominated by S. epidermidis . Patients with LBI had a bacterial skin flora dominated by potentially pathogenic bacteria., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Competing Interests: No Conflict of Interest is declared

Background: Colistin is a last resort antibiotic for the treatment of carbapenem-resistant Gram negative infections. Until recently, mechanisms of colistin resistance were limited to chromosomal mutations which confer a high fitness cost and cannot be transferred between organisms. However, a novel plasmid-mediated colistin resistance mechanism, encoded by the mcr-1 gene, has been identified, and has since been detected worldwide. The mcr-1 colistin resistance mechanism is a major threat due to its lack of fitness cost and ability to be transferred between strains and species. Surveillance of colistin resistance mechanisms is critical to monitor the development and spread of resistance.This study aimed to determine the prevalence of the plasmid-mediated colistin resistance gene, mcr-1, in colistin-resistant E. coli and Klebsiella spp . isolates in the Western Cape of South Africa; and whether colistin resistance is spread through clonal expansion or by acquisition of resistance by diverse strains., Methods: Colistin resistant E. coli and Klebsiella spp. isolates were collected from the NHLS microbiology laboratory at Tygerberg Hospital. Species identification and antibiotic susceptibility testing was done using the API® 20 E system and the Vitek® 2 Advanced Expert System™. PCR was used to detect the plasmid-mediated mcr-1 colistin resistance gene and REP-PCR was used for strain typing of the isolates., Results: Nineteen colistin resistant isolates, including 12 E. coli , six K. pneumoniae and one K. oxytoca isolate, were detected over 7 months from eight different hospitals in the Western Cape region. The mcr-1 gene was detected in 83% of isolates which were shown to be predominantly unrelated strains., Conclusions: The plasmid-mediated mcr-1 colistin resistance gene is responsible for the majority of colistin resistance in clinical isolates of E. coli and Klebsiella spp. from the Western Cape of South Africa. Colistin resistance is not clonally disseminated; the mcr-1 gene has been acquired by several unrelated strains of E. coli and K. pneumoniae. Acquisition of mcr-1 by cephalosporin- and carbapenem-resistant Gram negative bacteria may result in untreatable infections and increased mortality. Measures need to be implemented to control the use of colistin in health care facilities and in agriculture to retain its antimicrobial efficacy.

In this study, the therapeutic efficacy of cefazolin was compared with that of extended-spectrum cephalosporins (ESCs) (cefotaxime, ceftriaxone and ceftazidime) as appropriate empirical therapy in adults with community-onset monomicrobial bacteraemia caused by Escherichia coli, Klebsiella spp. or Proteus mirabilis (EKP). Compared with cefazolin-treated patients (n = 135), significantly higher proportions of patients in the ESC treatment group (n = 456) had critical illness at bacteraemia onset (Pitt bacteraemia score ≥4) and fatal co-morbidities (McCabe classification). Of the 591 patients, 121 from each group were matched using propensity score matching (PSM) based on the following independent predictors of 28-day mortality: fatal co-morbidities (McCabe classification); Pitt bacteraemia score ≥4 at bacteraemia onset; initial syndrome of septic shock; and bacteraemia due to pneumonia. After appropriate PSM, no significant differences were observed in the early clinical failure rate (10.7% vs. 7.4%; P = 0.37), the proportion of critical illness (Pitt bacteraemia score ≥4) (0% vs. 0%; P = 1.00) and defervescence (52.6% vs. 42.6%; P = 0.13) on Day 3 between the cefazolin and ESC treatment groups. Similarly, no significant differences were observed in the mean of time to defervescence (4.1 days vs. 4.9 days; P = 0.15), late clinical failure rate (18.2% vs. 10.7%; P = 0.10) and 28-day crude mortality rate (0.8% vs. 3.3%; P = 0.37) between the two groups. These data suggest that the efficacy of cefazolin is similar to that of ESCs when used as appropriate empirical antimicrobial treatment for community-onset EKP bacteraemia., (Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.)

This study was conducted in Iran in order to assess the distribution of CTX-M type ESBLs producing Enterobacteriaceae. From January 2012 to December 2013, totally 198 E. coli, 139 Klebsiella spp, 54 Salmonella spp and 52 Shigella spp from seven hospitals of six provinces in Iran were screened for resistance to extended-spectrum cephalosporins. After identification and susceptibility testing, isolates presenting multiple-drug resistance (MDR) were evaluated for ESBL production by the disk combination method and by Etest using (cefotaxime and cefotaxime plus clavulanic acid). All isolates were also screened for blaCTX-M using conventional PCR. A total of 42.92%, 33.81%, 14.81% and 7.69% of the E. coli, Klebsiella spp, Salmonella spp and Shigella spp isolates were MDR, respectively. The presence of CTX-M enzyme among ESBL-producing isolates was 85.18%, 77.7%, 50%, and 66.7%, in E. coli, Klebsiella spp, Salmonella spp and Shigella spp respectively. The overall presence of CTX-M genes in Enterobacteriaceae was 15.4% and among the resistant isolates was 47.6%. This study indicated that resistance to β-lactams mediated by CTX-M enzymes in Iran had similar pattern as in other parts of the world. In order to control the spread of resistance, comprehensive studies and programs are needed., (Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.)

We evaluated the frequency of occurrence and antimicrobial susceptibility patterns of Gram-negative bacteria isolated from bacteremic patients with UTI from European (EU) and United States (USA) hospitals during a 3-year period (2009-2011). Susceptibility testing was performed by the reference broth microdilution method on 2071 Gram-negative bacilli. The most frequently isolated pathogens were Escherichia coli (63·3/71·3% in USA/EU), Klebsiella spp. (16·7/11·2%) and Proteus mirabilis (6·4/5·0%). Escherichia coli susceptibility rates were generally similar in the USA and EU, with extended-spectrum beta-lactamase (ESBL)-phenotype rates at 8·1% in both regions. Among Klebsiella spp., ESBL rates varied from 11·4/17·1% in 2009 to 16·1/40·4% in 2011 in USA/EU, and susceptibility rates were generally lower in EU compared to the USA. Pseudomonas aeruginosa exhibited lower susceptibility rates to ceftazidime, meropenem and piperacillin/tazobactam in EU (78·4, 78·4 and 76·5%, respectively) compared to USA (91·2, 88·2 and 91·2%, respectively). In summary, very few antimicrobials provided satisfactory coverage (>90%) when tested against Klebsiella spp. and P. aeruginosa isolates in EU.