Presence Of blaCTX-M Research Articles

Prevalence and characteristics of ESBL-producing Escherichia coli in clinically healthy pigs: implications for antibiotic resistance spread in livestock.

This study aimed to compare and characterize the resistance profile and the presence of extended-spectrum beta-lactamase (ESBL) related genes in Escherichia coli isolated from healthy finishing pigs fed with or without antibiotics in their diets. A total of 27 ceftiofur-resistant E. coli isolates were obtained from 96 healthy pigs. The antibiotic resistance profile was tested, and all 27 isolates were classified as multidrug-resistant (MDR). A high proportion of isolates were resistant to cephalosporins, ampicillin, ciprofloxacin, and tetracyclines. The ESBL production was observed in 85% of isolates by double-disc synergy test. The MDR-E. coli isolates harbored ESBL genes, such as blaTEM, blaCTX-M-1, blaCTX-M-2, and blaCTX-M-8,25. In addition, other antibiotics resistance genes (ARGs) were also detected, such as sul2, ant(3″)-I, tetA, and mcr-1. The mobilization of the blaCTX-M gene was confirmed for nine E. coli isolates by conjugation assays. The presence of blaCTX-M on mobile genetic elements in these isolates was demonstrated by Southern blot hybridization, and the resistance to cephalosporins was confirmed in the transconjugants. Our results indicate the prevalence of CTX-M-producing E. coli strains harboring mobile genetic elements in the normal microbiota of healthy pigs. These findings highlight the significance of ESBL genes as a global health concern in livestock and the potential spread of antimicrobial resistance to other members of the gastrointestinal tract microbiota.

SURVEY ON MULTI-DRUG RESISTANT AND EXTENDED SPECTRUM BETA LACTAMASES PRODUCING BACTERIA ON CONTACT SURFACES AT MURTALA MUHAMMAD SPECIALIST HOSPITAL, MAKKAH EYE CLINIC AND UMC ZHAHIR HOSPITAL, KANO STATE

The contaminated environmental surfaces are not only potential reservoirs for spread of microbial agents inside hospital but also in community. The development and evolution of antimicrobial resistance in pathogen has been reported to be one of the major issues confronting the global health community. Members of family Enterobacteriacae able to produce extended spectrum of beta lactamase which is responsible to hydrolyze the third generation of cephalosporin group antibiotics resulting treatment failure. The use of beta-lactams has increased considerably since its discovery so also resistant genes leading to Extended-Spectrum Beta-Lactamases (ESBL) mediated by the presence of blaCTX-M, blaTEM, and blaSHV genes present in most Gram-negative bacteria. Out of 300 swab samples collected, 218 (72.7%) bacteria were isolated. 158 (72.5%) was gram positive and 60(27.5%) was gram negative. A total of 96(44.0%) isolates were multidrug resistant. Antibiotics susceptibility test was performed by Kirby Bauer technique according to CLSI guidelines. Organisms that tested positive phenotypically for ESBL were subjected to PCR for molecular analysis. ESBL had a percentage rate of 11.3%. The coexistence of bla CTX-M, bla TEM and bla SHV gene was detected

Molecular characterization and antibiotic resistance profile of ESBL-producing Escherichia coli isolated from healthy cow raw milk in smallholder dairy farms in Bangladesh.

The emergence of antimicrobial-resistant bacteria, such as Escherichia coli in milk, is a serious public health concern as milk is considered a complete food and an important part of daily human diet worldwide, including in Bangladesh. However, there have been no reports on the molecular characterization and antibiotic resistance profile of extended-spectrum beta-lactamase (ESBL)-producing E. coli from milk of healthy cows in Bangladesh. Therefore, this study aimed to detect and characterize ESBL-producing E. coli (ESBL-Ec) in milk samples from healthy cows in smallholder dairy farms in Mymensingh district, Bangladesh, and assess the potential risk of consuming this milk. A total of 100 milk samples were collected from apparently healthy cows on smallholder dairy farms. Escherichia coli was isolated from the collected samples using standard methods. The detection of ESBL-Ec was performed phenotypically using cultural methods and genotypically by ESBL genetic determinants using multiplex polymerase chain reaction. Antimicrobial susceptibility testing of the ESBL-Ec isolates was performed using the disk diffusion method with 15 common antimicrobials. In this study, out of the 100 samples tested, 70 (70%) were found to be positive for E. coli. Among these, 41 (58.6%) strains were identified as ESBL-producing, both phenotypically and genotypically, with the presence of blaCTX-M, blaTEM, and blaSHV individually or combined (blaCTX-M plus blaTEM plus blaSHV). The antibiogram of these ESBL-positive isolates revealed high resistance against commonly used antibiotics, such as ampicillin, cefotaxime, and gentamicin (100%), azithromycin (88%), oxytetracycline (27%), nalidixic acid, cotrimoxazole/trimethoprim (24%), and streptomycin (22%). In addition, one isolate showed resistance to 4th generation of cephalosporin (cefepime). Most importantly, extensive multidrug resistance was found in many ESBL-Ec isolates. However, the isolates were highly sensitive to drugs such as ceftriaxone (100%) and imipenem (100%). This is the first study to detect ESBL-Ec in raw milk from healthy cows on smallholder dairy farms in Bangladesh. More than 58% of the E. coli isolated from raw milk of healthy cows tested positive for ESBL production and showed resistance to most commonly used antimicrobials which may be alarming for human health. A limitation of our study is that we had a small size of sample collected from one district in Bangladesh. Therefore, a larger sample size covering a wider geographic area, and using multi-locus sequence typing and whole genome sequencing could provide a more comprehensive understanding of the prevalence and characteristics of ESBL-Ec in Bangladesh.

High Prevalence of blaCTX-M in Fecal Commensal Escherichia coli from Healthy Children.

BackgroundAntibiotic-resistant Escherichia coli can colonize the intestinal tract of healthy children, causing concern when antibiotic resistance is related to the presence of transferable mechanisms, such as extended-spectrum β-lactamases (ESBLs).Materials and MethodsFecal samples from 41 healthy children from two villages of rural Peru were cultured on ceftriaxone-disks. ESBL production was confirmed with double disk synergy. In all ESBL-produced isolates, antibiotic susceptibility to 12 antibacterial agents was established by disk diffusion, while clonal relationships were determined by repetitive extragenic palindromic-polymerase chain reaction (REP-PCR). Presence of ST131 was determined using PCR.ResultsCeftriaxone-resistant microorganisms were recovered from 39 samples belonging to 22 out of 41 children (53.7%). Of these, 80 ceftriaxone-resistant and two ceftriaxone-intermediate E. coli from inside ceftriaxone-halos were confirmed as ESBL-producers. All isolates were multidrug-resistant. In 79/80 (98.8%) ceftriaxone-resistant isolates, the presence of blaCTX-M was detected alone (58 isolates, or together with other β-lactamase (blaTEM, 17 isolates; blaOXA-1-like, 3 isolates; blaTEM + blaOXA-1-like, 1 isolate), while in one isolate no such ESBL was identified. The two ceftriaxone-intermediate isolates recovered from the same sample, carried a blaTEM and blaSHV respectively. Thirty-four different clones were identified, with 4 clones being recovered from different samples from the same child. Twelve clones were disseminated among different children, including 5 clones disseminated between both villages. Two clones, accounting for 3 isolates and both recovered from the same children, belonged to E. coli ST131.ConclusionThis study demonstrates high prevalence of ESBL-carriers among healthy children living in a rural area of Peru, stressing the need for continuous surveillance and search for public health control measures.

The distribution of extended-spectrum Beta-Lactamase genes in Fomites, healthcare workers, and patients from two hospitals in Lagos state, Nigeria

Antibiotics resistance is a rapidly emerging issue through the misuse of antibiotics to treat human and animalrelated infections. The use of beta-lactams has increased considerably since its discovery so also resistant genes leading to Extended-Spectrum Beta-Lactamases (ESBL) mediated by the presence of blaCTX-M , blaTEM and blaSHV genes present in most Gram-negative bacteria. This study aimed to detect the widespread distribution of ESBL genes from fomites, healthcare workers, and patients suffering from urinary tract infection in two hospitals in Lagos state, Nigeria. A total of 150 swab samples were collected from fomites, health care workers, and cathetersof patients suffering from urinary tract infection (UTI). Antibiotics susceptibility test was performed by Kirby- Bauer technique according to CLSI guidelines. Organisms that tested positive phenotypically for ESBL were subjected to PCR for molecular analysis. ESBL prevalence rate of 21.8% and a carbapenemase-resistance rate of 16.7% were recorded. The ESBL producing isolates showed the highest resistance to ceftriaxone (82.4%) and the least resistance to tigecycline (5.9%). The existence of blaCTX-M and blaTEM was detected in 76.5% and 17.6% of the isolates respectively, while bla encoding gene was not detected in this study. The distribution of blaSHV genes detected in this study is of great concern which necessitates strict control measures in the usage of antibiotics especially the third-generation cephalosporin. In summary, the presence and distribution of ESBL encoding genes within two hospitals in Lagos were tested and the highest occurrence was recorded in blaCTX-M gene reducing and limiting the available treatment option for infections.

Molecular Characterization of Antibiotic Resistance Associated with TEM and CTX-M ESBL in Uropathogenic E. coli Strains Isolated from Outpatients

Background & Objective: Escherichia coli (E. coli) is a leading cause of urinary tract infections becoming resistant against beta-lactams and cephalosporins through different mechanisms, including ESBL production due to the presence of ESBL specific genes, including blaCTX-M and blaTEM. The purpose of the present study was to detect the uropathogenic E. coli strains producing the ESBL.Methods: A total of 100 isolates of uropathogenic E. coli were randomly selected in a period of 6 months and their resistances to a number of antibiotics including amoxicillin, amikacin, gentamicin, ciprofloxacin, ceftazidime, cefotaxime, ceftriaxone, ceftizoxime, nalidixic acid, and nitrofurantoin were determined. Then, DDT test was used to detect the presence of ESBL. Finally, the presence of blaCTX-M and blaTEM resistance genes was analyzed by PCR method.Results: The resistance profile of bacterial isolates to the antibiotics was as follows: amoxicillin: 16.7%, amikacin: 7.8%, gentamicin: 20.3%, ciprofloxacin: 35.5/%, ceftazidime: 35.0%, cefotaxime: 40.0%, ceftriaxone: 41.3%, nalidixic acid: 64.0%, nitrofurantoin: 9.7%, and ceftizoxime: 100%. Of these, 28 isolates (28%) were reported to be resistant to cefotaxime, ceftazidime, and ceftriaxone. In DDT test, 21 ESBL positive cases (21%) were detected. PCR results showed that the presence of blaCTX-M and blaTEM genes in the isolates were 21% and 20%, respectively. Conclusion: Regarding the production of ESBL by some E. coli isolates, phenotypic detection of ESBL-producing isolates is routinely suggested in the laboratories. Likewise, the treatment regimen should be selected regarding the ESBL production to avoid treatment failure.

High fecal carriage of blaCTX-M, blaCMY-2, and plasmid-mediated quinolone resistance genes among healthy Korean people in a metagenomic analysis

To characterize the carriage of antibiotic resistance genes (ARGs) in the gut microbiome of healthy individuals. Fecal carriage of ARGs was investigated in 61 healthy individuals aged 30 to 59 years through whole metagenome sequencing of the gut microbiome and a targeted metagenomic approach. The number of ARGs in the gut microbiome was counted and normalized per million predicted genes (GPM). In the Korean population, the resistome ranged from 49.7 to 292.5 GPM (median 89.7). Based on the abundance of ARGs, the subjects were categorised into high (> 120 GPM), middle (60‒120 GPM), and low (< 60 GPM) ARG groups. Individuals in the high ARG group tended to visit hospitals more often (P = 0.065), particularly for upper respiratory tract infections (P = 0.066), and carried more blaCTX-M (P = 0.008). The targeted metagenome approach for bla and plasmid-mediated quinolone resistance (PMQR) genes revealed a high fecal carriage rate; 23% or 13.1% of the subjects carried blaCTX-M or blaCMY-2, respectively. Regarding PMQR genes, 59% of the subjects carried PMQR, and 83% of them harboured 2‒4 PMQR genes (qnrB 44.3%, qnrS 47.5% etc.). The presence of blaCTX-M correlated with ARG abundance in the gut resistome, whereas PMQR genes were irrelevant to other ARGs (P = 0.176). Fecal carriage of blaCTX-M and PMQR genes was broad and multiplexed among healthy individuals.

Impact of Sodium Alginate Packaging Film Synthesized Using Syzygium cumini Seed Extract on Multi Drug Resistant Escherichia coli Isolated from Raw Buffalo Meat.

A total of 50 Escherichia coli were isolated from buffalo meat and their antibiotic profiling was carried out. 90% E. coli isolates showed resistant to two or more classes of 21 commonly used antibiotics. Moreover, there was also variation in resistance/sensitivity behavior towards antibiotics. Highest resistance was found to be against methicillin (84%) in the isolates followed by vancomicin (70%), sulphadiazine (68%) and cefaclor (66%), whereas, resistance was less common for kanamycin (8%) and chloramphenicol (4%). ECMB1, ECMA2, ECMA8, ECMS9 and ECMA31 strains showed highest MDR pattern with presence of bla CTX-M, qnr S and qnr B resistant genes. ECMB1 strain was resistant to 14 antibiotics belonging to 7 different classes. Therefore, ECMB1 was selected for further studies. Sodium Alginate Film incorporated with 10, 20, and 30% ethanolic extract of Syzygium cumini (EESC) were formulated and characterized using state-of-art techniques. A dose-dependent antibacterial activity against E. coli ECMB1 was recorded by the films made from EESC (EESCF). The growth kinetics of E. coli strain ECMB1 showed 9% decrease in log CFU when it was cultured in 30% EESCF as compared to control cells after 12h of growth. Present finding highlight the efficacy and possible use of EESCF as meat packaging film to prevent food spoilage caused by MDR bacteria.

Molecular Characterization of Antibiotic Resistance Associated with TEM and CTX-M ESBL in Uropathogenic E. coli Strains Isolated from Outpatients.

Background & Objective:Escherichia coli (E. coli) is a leading cause of urinary tract infections becoming resistant against beta-lactams and cephalosporins through different mechanisms, including ESBL production due to the presence of ESBL specific genes, including blaCTX-M and blaTEM. The purpose of the present study was to detect the uropathogenic E. coli strains producing the ESBL.Methods:A total of 100 isolates of uropathogenic E. coli were randomly selected in a period of 6 months and their resistances to a number of antibiotics including amoxicillin, amikacin, gentamicin, ciprofloxacin, ceftazidime, cefotaxime, ceftriaxone, ceftizoxime, nalidixic acid, and nitrofurantoin were determined. Then, DDT test was used to detect the presence of ESBL. Finally, the presence of blaCTX-M and blaTEM resistance genes was analyzed by PCR method.Results:The resistance profile of bacterial isolates to the antibiotics was as follows: amoxicillin: 16.7%, amikacin: 7.8%, gentamicin: 20.3%, ciprofloxacin: 35.5/%, ceftazidime: 35.0%, cefotaxime: 40.0%, ceftriaxone: 41.3%, nalidixic acid: 64.0%, nitrofurantoin: 9.7%, and ceftizoxime: 100%. Of these, 28 isolates (28%) were reported to be resistant to cefotaxime, ceftazidime, and ceftriaxone. In DDT test, 21 ESBL positive cases (21%) were detected. PCR results showed that the presence of blaCTX-M and blaTEM genes in the isolates were 21% and 20%, respectively. Conclusion:Regarding the production of ESBL by some E. coli isolates, phenotypic detection of ESBL-producing isolates is routinely suggested in the laboratories. Likewise, the treatment regimen should be selected regarding the ESBL production to avoid treatment failure.

Molecular diversity of Extended‐spectrum β‐lactamase‐producing Escherichia coli from vultures in Canary Islands

Antimicrobial resistance among isolates from wild animals is increasingly reported. Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, and particularly Escherichia coli, have spread worldwide as one of the most common multidrug-resistant organisms. The aim of this study was to determine the carriage rate of ESBL-producing E. coli isolates and their genetic characteristics in wild vultures from the Canary Islands. Faecal samples were collected from 22 apparently healthy free-ranging (wild) vulture chicks from Lanzarote and Fuerteventura (Canary Islands) during July 2019. They were seeded in MacConkey agar supplemented with cefotaxime (2 μg ml-1 ). Colonies with typical morphology of E. coli were identified by MALDI-TOF-MS. Antimicrobial susceptibility was done by disk diffusion. Phenotypic detection of ESBL was performed by double-disk tests. The presence of blaCTX-M , blaSHV , blaTEM , blaKPC and blaOXA-48 genes, as well as mcr-1 (colistin resistance), tetA/tetB and int1 gene, was tested by PCR/sequencing. Phylogenetic groups and multilocus sequence typing (MLST) were determined by PCR/sequencing. ESBL-producing E. coli isolates were detected in 5/22 tested animals (22.7%), and all isolates (one/animal) carried blaCTX-M genes: blaCTX-M-15 (n = 3) and blaCTX-M-55 (n = 2). ESBL-positive isolates were ascribed to phylogenetic group D (two isolates), B1 (two isolates) and A (one isolate), and five sequence types were detected (ST/phylogenetic-group/ESBL): ST515/B1/CTX-M-15, ST1290/A/CTX-M-15, ST38/D/CTX-M-15, ST457/D/CTX-M-55 and ST6448/B1 /CTX-M-55; this suggests a genetic diversity among these isolates. Three CTX-M-15-producing isolates contained the blaTEM gene and one the tetA gene. To our knowledge, this appears to be the first report of ESBL-producing E. coli in vulture chicks from the Canary Islands.

Escherichia coli Producing Extended-Spectrum β-lactamases (ESBL) from Domestic Camels in the Canary Islands: A One Health Approach.

This work aimed to determine the carriage rate of ESBL-producing Escherichia coli as well as their genetic characteristics in camels from the Canary Islands, Spain. Fecal samples were recovered from 58 healthy camels from Gran Canaria (n = 32) and Fuerteventura Islands (n = 26) during July 2019. They were seeded on MacConkey (MC) agar no supplemented and supplemented (MC + CTX) with cefotaxime (2 µg/mL). Antimicrobial susceptibility was determined by disk diffusion test (CLSI, 2018). The presence of blaCTX-M, blaSHV, blaTEM,blaCMY-2 and blaOXA-1/48 genes was tested by PCR/sequencing. Furthermore, the mcr-1 (colistin resistance), tetA/tetB (tetracycline resistance), int1 (integrase of class 1 integrons) and stx1,2 genes were analyzed. Phylogenetic groups and sequence types were determined by specific-PCR/sequencing for selected isolates. E. coli was obtained from all the 58 camels in MC media (100%) and in five of them in MC + CTX media (8.6%). Furthermore, 63.8% of E. coli isolates recovered from MC agar were susceptible to all the antibiotics tested. The five E. coli isolates recovered from MC + CTX media were characterized and two of them were ESBL-producers (3.4%). Both ESBL-producer isolates carried the blaCTX-M-15 gene and belonged to the lineages ST3018 (phylogroup A) and ST69 (phylogroup B1). The 3 ESBL-negative isolates recovered from MC-CTX plates were ascribed to phylogroup-B1. Camels can be a source of ESBL-producer bacteria, containing the widespread blaCTX-M-15 gene associated with the lineages ST3018 and ST69.

Prevalence of SHV, TEM, CTX-M and OXA-48 β-Lactamase Genes in Clinical Isolates of Pseudomonas aeruginosa in Bandar-Abbas, Iran

Background: Pseudomonas aeruginosa is one of the most important causes of opportunistic infections. Carbapenems are administrated for the treatment of resistant infections due to this bacterium. The aim of this study was to investigate the presence of blaSHV, blaTEM, blaCTX-M and blaOXA-48 beta-lactamase genes in clinical isolates of P. aeruginosa in Bandar Abbas, Iran. Methods: In this descriptive study, 96 isolates of P. aeruginosa were obtained from clinical samples in Bandar Abbas. All isolates were identified by biochemical tests. The antibiotic susceptibility was examined by disk diffusion method. The presence of blaCTX-M, blaSHV, blaTEM and blaOXA-48 genes was evaluated by polymerase chain reaction using a specific primer. Results: In this study, 76 isolates of P. aeruginosa (79.2%) were resistant to at least one carbapenem. The highest bacterial resistance (100%) was obtained to nalidixic acid (30 µg), followed by tetracycline (30 µg) and amoxicillin (25 µg). The frequencies of blaCTX-M, blaSHV, blaTEM and blaOXA-48 genes were 23.95% (23 isolates), 23.08% (26 isolates), 57.29% (55 isolates) and 12.5% (12 isolate), respectively. Sixty isolates resistant to carbapenems (78.9%) carried at least one resistant gene (blaTEM, blaSHV, blaCTX-M and blaOXA-48) and 16 isolates (21.1%) did not have any of these genes. Conclusions: This study revealed the prevalence of carbapenem-resistant phenotype of P. aeruginosa clinical isolates and the frequency of extended-spectrum β-lactamase genes have increased.

T4-like Escherichia coli phages from the environment carry blaCTX-M.

The CTX-M gene that confers resistance to Beta-lactam class of drugs is widespread and diverse. Understanding mechanisms of antimicrobial resistance transfer is a key to devise methods for controlling it. Few studies indicate that bacteriophages are involved in the transfer of this gene but the type of phages involved and the degree of involvement remains to be explored. Our work has been able to identify the class of phages and the magnitude of involvement in the dissemination of this gene.

Prevalence and risk factors for CTX-M gram-negative bacteria in hospitalized patients at a tertiary care hospital in Kilimanjaro, Tanzania

Emergence and spread of extended spectrum beta-lactamase (ESBL)-producing gram-negative bacteria, mainly due to CTX-M, is a major global public health problem. Patients infected with ESBL-producing gram-negative bacteria have an increased risk of treatment failure and death. We investigated the prevalence and risk factors for CTX-M gram-negative bacteria isolated from clinical specimens of patients hospitalized at a tertiary care hospital in Kilimanjaro, Tanzania. Isolated gram-negative bacteria from inpatients admitted at Kilimanjaro Christian Medical Centre (KCMC) between August 2013 and August 2015 were fully genome sequenced. The prevalence of ESBL-producing gram-negative bacteria was determined based on the presence of blaCTX-M. The odds ratio (OR) and risk factors for ESBL-producing gram-negative bacteria due to CTX-M were assessed using logistic regression models. The overall CTX-M prevalence (95% CI) was 13.6% (10.1–18.1). Adjusted for other factors, the OR of CTX-M gram-negative bacteria for patients previously hospitalized was 0.26 (0.08–0.88), p = 0.031; the OR for patients currently on antibiotics was 4.02 (1.29–12.58), p = 0.017; the OR for patients currently on ceftriaxone was 0.14 (0.04–0.46), p = 0.001; and the OR for patients with wound infections was 0.24 (0.09–0.61), p = 0.003. The prevalence of ESBL-producing gram-negative bacteria due to CTX-M in this setting is relatively low compared to other previous reports in similar settings. However, to properly stop further spread in the hospital, we recommend setting up a hospital surveillance system that takes full advantage of the available next-generation sequencing facility to routinely screen for all types of bacterial resistance genes.

Characterization of CTX-M enzymes, quinolone resistance determinants, and antimicrobial residues from hospital sewage, wastewater treatment plant, and river water

Multidrug-resistant (MDR) bacteria are widespread in hospitals and have been increasingly isolated from aquatic environments. The aim of the present study was to characterize extended-spectrum β-lactamase (ESBL) and quinolone-resistant Enterobacteriaceae from a hospital effluent, sanitary effluent, inflow sewage, aeration tank, and outflow sewage within a wastewater treatment plant (WWTP), as well as river water upstream and downstream (URW and DRW, respectively), of the point where the WWTP treated effluent was discharged. β-lactamase (bla) genes, plasmid-mediated quinolone resistance (PMQR), and quinolone resistance-determining regions (QRDRs) were assessed by amplification and sequencing in 55 ESBL-positive and/or quinolone-resistant isolates. Ciprofloxacin residue was evaluated by high performance liquid chromatography. ESBL-producing isolates were identified in both raw (n=29) and treated (n=26) water; they included Escherichia coli (32), Klebsiella pneumoniae (22) and Klebsiella oxytoca (1). Resistance to both cephalosporins and quinolone was observed in 34.4% of E. coli and 27.3% of K. pneumoniae. Resistance to carbapenems was found in 5.4% of K. pneumoniae and in K. oxytoca. Results indicate the presence of blaCTX-M (51/55, 92.7%) and blaSHV (8/55, 14.5%) ESBLs, and blaGES (2/55, 3.6%) carbapenemase-encoding resistance determinants. Genes conferring quinolone resistance were detected at all sites, except in the inflow sewage and aeration tanks. Quinolone resistance was primarily attributed to amino acid substitutions in the QRDR of GyrA (47%) or to the presence of PMQR (aac-(6′)-Ib-cr, oqxAB, qnrS, and/or qnrB; 52.9%) determinants. Ciprofloxacin residue was absent only from URW. Our results have shown strains carrying ESBL genes, PMQR determinants, and mutations in the gyrA QRDR genes mainly in hospital effluent, URW, and DRW samples. Antimicrobial use, and the inefficient removal of MDR bacteria and antibiotic residue during sewage treatment, may contribute to the emergence and spreading of resistance in the environment, making this a natural reservoir.

Prevalence and Diversity of Salmonella Serotypes in Ecuadorian Broilers at Slaughter Age.

Salmonella is frequently found in poultry and represent an important source for human gastrointestinal infections worldwide. The aim of this study was to investigate the prevalence, genotypes and antimicrobial resistance of Salmonella serotypes in broilers from Ecuador. Caeca content from 388 at random selected broiler batches were collected in 6 slaughterhouses during 1 year and analyzed by the ISO 6579/Amd1 protocol for the isolation for Salmonella. Isolates were serotyped and genotypic variation was acceded by pulsed field gel electrophoresis. MIC values for sulfamethoxazole, gentamicin, ciprofloxacin, ampicillin, cefotaxime, ceftazidime, tetracycline, streptomycin, trimethropim, chloramphenicol, colistin, florfenicol, kanamycin and nalidixic acid were obtained. Presence of blaCTX-M, blaTEM, blaSHV and blaCMY; and mcr-1 plasmid genes was investigated in resistant strains to cefotaxime and colistin respectively. Prevalence at batch level was 16.0%. The most common serotype was S. Infantis (83.9%) followed by S. Enteritidis (14.5%) and S. Corvallis (1.6%). The pulsed field gel electrophoresis analysis showed that S. Corvallis, S. Enteritidis and S. Infantis isolates belonged to 1, 2 and 12 genotypes respectively. S. Infantis isolates showed high resistance rates to 12 antibiotics ranging from 57.7% (kanamycin) up to 98.1% (nalidixic acid and sulfamethoxazole). All S. Enteritidis isolates showed resistance to colistin. High multiresistant patterns were found for all the serotypes. The blaCTX-M gene was present in 33 S. Infantis isolates while mcr-1 was negative in 10 colistin resistant isolates. This study provides the first set of scientific data on prevalence and multidrug-resistant Salmonella coming from commercial poultry in Ecuador.

Multidrug resistance and transferability of blaCTX-M among extended-spectrum β-lactamase-producing enteric bacteria in biofilm.

This study aimed to investigate the occurrence of biofilm-forming extended-spectrum β-lactamase (ESBL)-producing enteric bacteria in hospital wastewater and to evaluate their antibiotic resistance behaviour and transferability of the plasmid-encoded blaCTX-M gene in biofilm. ESBL production was confirmed using the combined disc test and Etest. Amplification of blaCTX-M was performed by PCR. Antibiotic susceptibility was evaluated using the disc diffusion assay and broth dilution method. Transfer of blaCTX-M in planktonic and biofilm state was performed by broth mating and filter mating experiments, respectively. Among 110 enteric bacteria, 24 (21.8%) isolates belonging to Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae were found to produce ESBL and formed varying levels of biofilm in vitro. Presence of blaCTX-M was detected in 18 (75%) ESBL-producing isolates. A many fold increase in resistance to antibiotics was observed in biofilm. Among ESBL-producers, seven isolates could transfer the blaCTX-M gene by conjugation, with transfer frequencies ranging from 2.22×10(-4) to 7.14×10(-2) transconjugants/recipient cell in the planktonic state and from 3.04×10(-3) to 9.15×10(-1) in biofilm. The transfer frequency of blaCTX-M was significantly higher in biofilm compared with the planktonic state, and co-transfer of ciprofloxacin resistance was also detected in five isolates. This study demonstrates that biofilm-forming ESBL-producing enteric bacteria with a greater transfer frequency of resistance genes will lead to frequent dissemination of β-lactam and fluoroquinolone resistance genes in environmental settings. The emergence and spread of such multidrug resistance is a serious threat to animal and public health.

High Frequency of Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae and Escherichia coli Isolates From Male Patients’ Urine

Background: The number of extended-spectrum -lactamase (ESBL)-producing Enterobacteriaceae reported cases all over the world has continued to increase faster than the other resistance mechanisms, particularly in E. coli and K. pneumoniae. Objectives: This cross-sectional study was designed to assess the prevalence of multidrug resistance of ESBL-producing urine isolates of E. coli and K. pneumoniae collected in Tehran hospitals, as well as the molecular characterizations of some ESBL genes, with an emphasis on occurrence rates by sex. Materials and Methods: A total of 190 E. coli and K. pneumoniae isolates were collected from patients’ urine samples in hospitals from Tehran, Iran during 2009 - 2010, and were screened for antibiotic susceptibility, ESBL phenotype, and presence of blaCTX-M and blaTEM genes. Minimal inhibitory concentration (MIC) for ceftazidime and cefotaxime were made by agar dilution method. Results: The ESBL phenotype was detected in 55.5% of E. coli and 46.4% of K. pneumoniae isolates. Presence of blaCTX-M-1 was dominant in both organisms. The prevalence of blaCTX-M-1 carrying isolates among ESBL-producing K. pneumoniae and E. coli isolates were 49.1% and 85.7%, respectively. Among ESBL-producing isolates, 68.5% of E. coli and 59.3% of K. pneumoniae isolates carried the blaTEM genes, and simultaneous carrying of blaCTX-M and blaTEM genes was observed in 68.5% of E. coli and 33.3% of K. pneumoniae isolates. The resistant rate to ceftazidime, cefotaxime, and cefepime was significantly higher in K. pneumoniae and E. coli isolates from male patients urine samples. A significant higher rate of blaCTX-M-1, blaTEM, and co-blaCTX-M-1-blaTEM genes were seen for E. coli and K. pneumoniae isolates in male patients’ urine. Conclusions: The results indicate that the rates of ESBLs are high in urine E. coli and K. pneumoniae isolates from Tehran hospitals. Also this study indicates that the urine isolates from male patients are significantly more resistant than the female isolates.

Presence of BlaCTX-M and BlaTEM among environmental Enterobacteriaceae isolated from the São Domingos River, Peniche, Portugal

Presence of BlaCTX-M and BlaTEM among environmental Enterobacteriaceae isolated from the São Domingos River, Peniche, Portugal

Fecal carriage of Escherichia coli harboring extended-spectrum beta-lactamase (ESBL) genes by sheep and broilers in Urmia region, Iran

Background: There is a growing concern on the impact of the presence of extended-spectrum β-lactamase (ESBL) producing Escherichia coli isolated from animals on public health. OBJECTIVES: The aim of this study was to investigate the presence of three classes of ESBL genes in E. coli isolates from sheep and broilers at a slaughter in Urmia region, Iran. METHODS: A total of 111 E. coli isolates were obtained from sheep (n=55) and broilers (n=56) fecal samples and the presence of blaCTX-M, blaTEM and blaSHV genes was detected by polymerase chain reaction (PCR). RESULTS: In general, 32 of these isolates carried blaCTX-M, 16 blaTEM, and 17 blaCTX-M plus blaTEM. None of the isolates tested was positive for the blaSHV gene. Among the 55 isolates from sheep, 33 (60%) contained one or more ESBL encoding gene; 15 (27.2%), 10 (18.2%), and 8 (14.5%) isolates were positive for blaCTX-M, blaTEM, and blaCTX-M+blaTEM, respectively. Among the 56 isolates from broilers, 32 (57.1%) isolates carried at least one ESBL encoding gene; 17 (30.4%) and 6 (10.7%) isolates were positive for blaCTX-M and blaTEM genes, respectively, and the blaCTX-M+ blaTEM was identified in nine isolates (16.1%). CONCLUSIONS: This study demonstrated that sheep and broiler feces may be a reservoir of E. coli harboring ESBLs genes, with CTX-M being the predominant β-lactamase type. This may pose a public health risk, which requires future evaluation and control.