Detection Of Extended-spectrum Β-lactamases Research Articles

Emerging threat: Antimicrobial resistance proliferation during epidemics — A case study of the SARS-CoV-2 pandemic in South Brazil

The escalating global concern of antimicrobial resistance poses a significant challenge to public health. This study delved into the occurrence of resistant bacteria and antimicrobial resistance genes in the waters and sediments of urban rivers and correlated this emergence and the heightened use of antimicrobials during the COVID-19 pandemic. Isolating 45 antimicrobial-resistant bacteria across 11 different species, the study identifies prevalent resistance patterns, with ceftriaxone resistance observed in 18 isolates and ciprofloxacin resistance observed in 13 isolates. The detection of extended-spectrum β-lactamases, carbapenemases, and acquired quinolone resistance genes in all samples underscores the gravity of the situation. Comparison with a pre-pandemic study conducted in the same rivers in 2019 reveals the emergence of previously undetected new resistant species, and the noteworthy presence of new resistant species and alterations in resistance profiles among existing species. Notably, antimicrobial concentrations in rivers increased during the pandemic, contributing significantly to the scenario of antimicrobial resistance observed in these rivers. We underscore the substantial impact of heightened antimicrobial usage during epidemics, such as COVID-19, on resistance in urban rivers. It provides valuable insights into the complex dynamics of antimicrobial resistance in environmental settings and calls for comprehensive approaches to combat this pressing global health issue, safeguarding both public and environmental health.

Predominance of OXA-48 Carbapenemase-Producing Enterobacterales in a Moroccan Hospital.

The emergence of carbapenemase-producing Enterobacterales (CPE) is a major concern that is increasingly reported worldwide. Our study aimed at investigating the resistance of CPE isolates in a Moroccan teaching hospital using phenotypic and genotypic methods. Enterobacterales strains from March to June 2018 were collected from different clinical samples. The Enterobacterales isolates resistant to third-generation cephalosporins (3GC) and/or carbapenems were subjected to the Carba NP test and an immunochromatographic test for phenotypic detection. Detection of extended-spectrum β-lactamases (ESBL) was also performed following standards. Molecular screening of carbapenemases genes (OXA-48, NDM, blaKPC, blaIMP, blaVIM, and blaOXA-24, blaOXA-23, OXA-51, OXA-58) using conventional multiplex PCR assays was also performed on 143 isolates. Enterobacterales represented 52.7% with a proportion of 21.8% of bacteria resistant to 3GC and/or carbapenems. Within 143 isolates MDR to 3GC, K. pneumoniae, E. coli, and E. cloacae represent 53.1%, 40.6%, and 6.3%, respectively. These strains were isolated mainly from urinary samples (74.8%) in patients admitted to emergency and surgical units. 81.1% of strains are producing ESBL and 29% are carbapenemase producers as confirmed by the Carba NP test, immunochromatographic test, and molecular testing. OXA-48 carriers represent 83.3% of these strains, followed by NDM with 16.7%. blaKPC, blaIMP, blaVIM, and blaOXA-24, blaOXA-23, OXA-51, OXA-58 were not detected in any of these bacteria. A high rate of CPE carrying OXA-48 among Enterobacterales resistant to 3GC and/or carbapenems isolates was found. Strict observance of hospital hygiene measures and more rational use of antibiotics are mandatory. Implantation of carbapenemases detection should be encouraged in our hospital settings to estimate the true burden of the CPE.

Antimicrobial resistance pattern of avian pathogenic Escherichia coli with detection of extended-spectrum β-lactamase-producing isolates in broilers in east Algeria.

Avian pathogenic Escherichia coli (APEC) is the causative agent of colibacillosis, one of the most prevalent bacterial diseases responsible for significant economic losses in the poultry industry worldwide. This study aimed to assess the antimicrobial resistance (AMR) patterns of APEC isolates recovered from poultry in east Algeria and estimate the prevalence of extended-spectrum β-lactamase (ESBL)-producing isolates. In the slaughterhouse of Batna City (Algeria), livers indicating colibacillosis were sampled from 204 suspected carcasses with growth retardation and generalized congestion. Escherichia coli isolation and identification were performed on MacConkey agar using conventional methods and the API 20E system. Antimicrobial resistance susceptibility was tested by the disk diffusion method according to the Clinical Laboratory Standards Institute Guidelines. Extended-spectrum β-lactamase detection was carried out using the double-disk confirmation test. One hundred sixty E. coli isolates were recovered (one isolate per sample). Avian pathogenic Escherichia coli isolates showed high levels of resistance to ampicillin and tetracycline (100%), nalidixic acid (95%), ofloxacin (93.75%), doxycycline (91.87), ciprofloxacin (87.50%), trimethoprim/sulfamethoxazole (62.50%), gentamycin (32.50%), chloramphenicol (27.50%), amoxicillin/clavulanic acid (16.25%), colistin (14.37%), and nitrofurantoin (10.62%). All strains were multidrug-resistant to at least three antibiotics, and more than half (52.52%) of the isolates were resistant to at least seven antibiotics. All isolates were susceptible to ceftriaxone, ceftazidime, and aztreonam. Two E. coli isolates were ESBL producers (1.25%). Avian pathogenic Escherichia coli resistance to most antimicrobial agents used in poultry may lead to antimicrobial therapy failure.

Detection of ESBL and AmpC producing Klebsiella pneumoniae ST11 and ST147 from urinary tract infections in Iran.

In the present study a total of 200 Klebsiella pneumoniae isolates were collected from patients with urinary tract infections (UTIs) in Tehran, Iran. Antibiotic resistance was determined by disk diffusion and broth dilution methods. Detection of extended-spectrum β-lactamases (ESBLs) and AmpCs was performed using phenotypic tests. Polymerase chain reaction (PCR) was applied to detect the ESBL, AmpC, and integron genes. Analysis of AmpC and cassette arrays of integron genes was performed using DNA sequencing. Plasmids were analyzed by PCR-based replicon typing and conjugation. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were applied to explore the genomic relatedness among the isolates. The highest levels of resistance were observed against ampicillin (100%), followed by piperacillin (57.5%), ceftazidime (46%), trimethoprim/sulfamethoxazole (44%), ciprofloxacin (32.5%), and imipenem (19%). Approximately, 66.5% of isolates harbored at least one of the beta-lactamase genes (blaTEM, blaSHV, blaCTX-M, and blaOXA-1). In addition, 22.5% of isolates carried at least one of the AmpC genes including blaDHA and blaCIT. Integron class I was the most prevalent integron among resistant isolates. According to the results of replicon typing, IncFII, IncL/M, and IncA/C were the most frequent replicons, respectively. All selected isolates were able to transfer blaCTX-M, also two isolates transferred the blaDHA-1 gene to Escherichia coli K12 through conjugation. Finally, 21 isolates were categorized into 4 pulsotypes and 11 unique clusters in PFGE. MLST identified ST147 and ST11 sequence types but ST147 was the most prevalent in the current study.

Evaluation of a diagnostic algorithm for rapid identification of Gram-negative species and detection of extended-spectrum β-lactamase and carbapenemase directly from blood cultures.

To evaluate a rapid diagnostic algorithm based on MALDI-TOF MS, lateral flow immunoassays (LFIAs) and molecular testing performed directly from positive blood cultures (BCs) for Gram-negative species identification and detection of CTX-M extended-spectrum β-lactamases and main carbapenemases. Non-duplicate BCs positive to Gram-negative bacteria at microscope examination were subjected to species identification by direct MALDI-TOF MS following recovery of bacterial pellet by Rapid MBT Sepsityper® kit. Subsequently, NG-Test® CARBA 5 and NG-Test® CTX-M MULTI LFIAs were performed according to identified microbial species. Eazyplex® SuperBug CRE molecular assay was performed in cases of NG-Test® CARBA 5 negative results in patients with documented carbapenemase-producers carriage. Results of rapid diagnostic workflow were compared with those obtained by conventional diagnostic routine. Overall, the direct MALDI-TOF MS protocol allowed reliable identification to the species level of 92.1% of the 2133 monomicrobial BCs. Rate of matched identification was significantly higher for Enterobacterales (97.3%) in comparison to non-fermenting Gram-negative species (80.2%), obligate anaerobic bacteria (42.1%) and fastidious Gram-negative species (41.5%). The overall sensitivity of NG-Test® CARBA 5 and NG-Test® CTX-M MULTI was 92.2% and 91.6%, respectively. Integration of Easyplex® SuperBug CRE allowed the detection of blaKPC mutants associated with ceftazidime/avibactam resistance, reaching 100% sensitivity in carbapenemase detection. Both LFIAs and molecular testing showed no false-positive results. Algorithms based on MALDI-TOF MS, LFIAs and molecular testing may represent a cost-effective tool to timely identify Gram-negative species and detect resistance markers directly from BCs. According to local epidemiology, these results may allow antimicrobial stewardship interventions including prompt use of new approved drugs.

The Diagnostic Capacity of Three Phenotypic Techniques of Extended-Spectrum β-Lactamase Detection

Background: Early detection of extended-spectrum β-lactamases (ESBLs) producing bacteria is critical for infection prevention and control. Numerous phenotypic approaches and automated systems have been developed for detecting ESBL bacteria. However, there is a scarcity of data in Ethiopia regarding the most reliable, simple, and cost-effective methods for detecting ESBL-producing bacteria. This study, therefore, aimed to evaluate the diagnostic performance of three phenotypic approaches for detecting ESBL-producing bacteria. Methods: In this study, 117 isolates of Klebsiella pneumoniae, Escherichia coli, Klebsiella oxytoca, and Proteus mirabilis were examined. Cefotaxime (30 µg) and ceftazidime (30 µg) were used for screening ESBL enzymes. A screening breakpoints of≤27 mm and≤22 mm were used for cefotaxime (30 µg) and ceftazidime (30 µg), respectively, as per the Clinical and Laboratory Standards Institute (CLSI) guidelines. All 117 strains were further confirmed by the Vitek 2 compact, double disk synergy, ESBL Epsilometer test, and combined disk method. The combined disk method was adopted as the reference method. Results: Out of 117 isolates, 90 (86%) had zone diameters of≤27 mm and≤22 mm for cefotaxime (30 µg) and ceftazidime (30 µg), respectively. The reference method detected 76 (65%) ESBL isolates out of 117 ones. From among the three techniques (i.e., double disk synergy, Vitek 2 compact, and ESBL Epsilometer test), the double disk synergy method demonstrated overall sensitivity and specificity of 97.4% and 97.6%, respectively. Vitek-2, cefotaxime, and ceftazidime Epsilometer test indicated indeterminate results of 6.8%, 6.8%, and 5.1% respectively. Conclusion: Double disk synergy was found to have the highest sensitivity and specificity for detecting ESBL isolates with no indeterminate results.

Resistance of Some Bacteria Isolated from Urinary Tract Infections in Elderly Patients to Antibiotics and Detection of β-lactamases in Them

Urinary tract infection is the second-largest infection, especially in elderly people, and the increasing use of antibiotics has led to the emergence and development of resistance in isolated and other bacteria in this study Fifty urine samples from elderly patients with urinary tract infections were collected from both sexes in Mosul city. Twenty-six bacterial isolates were isolated and diagnosed by ordinary bacteriological tests. The isolates were related to the species. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis. After isolation, their resistance to 14 selected antimicrobial agents was tested by the disk diffusion method. The presence of β-lactamases, in general, was detected by acidimetric method, the detection of extended-spectrum β-lactamases(ESBLs) was performed by double disk method, while the detection of AmpC β-lactamases was performed by cefoxitin resistance method. The isolates showed clear resistance to β-lactam antibiotics ranged (50%--92.3%),and to ciprofloxacin, gentamicin, sulfamethoxazole, streptomycin, rifampin with rates; (53.8%),(57.7%), (61.5%), (80.8%), (88.5%), respectively, while they showed reduced resistance to amikacin (15.4%). β-lactamases in general were detected in (96.1%) of the isolates, while (19.2%) of them gave a positive result for the detection of (ESBLs). AmpC β-lactamases were detected in (69.2%) of the isolates as they showed a clear resistance to cefoxitin which indicates that they are potential producers of these enzymes.

Epidemiologically relevant antimicrobial resistance phenotypes in surveillance cultures of a tertiary health service in Aracaju-SE

Introdução: O constante surgimento e a disseminação de fenótipos bacterianos de resistência a múltiplas drogas têm se tornado problemas de saúde pública em todo o mundo. Objetivo: Investigar a ocorrência de fenótipos críticos de resistência aos antimicrobianos em bactérias isoladas de culturas de vigilância. Método: Os dados microbiológicos foram coletados a partir de culturas de vigilância realizadas entre janeiro e dezembro de 2015 em um serviço terciário de saúde. Foram analisadas 1.590 culturas de vigilância utilizando o sistema VITEK 2 para identificação fenotípica e suscetibilidade aos antimicrobianos dos isolados. A detecção de β-lactamases de espectro estendido (ESBL) foi realizada por método de disco aproximação e a resistência aos carbapenêmicos e Staphylococcus aureus resistente à meticilina (MRSA) por métodos de disco difusão. A detecção de bactérias portadoras dos genes blaKPC, blaNDM e blaOXA-48 foi realizada através da reação em cadeia da polimerase in house. Resultados: Foram identificadas 201 (12,64%) fenótipos de ESBL, 173 (11,87%) de resistência aos carbapenêmicos e 3 (0,18%) de MRSA. Foram detectadas 34 cepas portadoras de genes codificadores de carbapenemases, onde 23 (67,64%) carreavam o gene blaKPC, oito (23,53%) o blaNDM e três (8,82%) ambos os genes. Conclusões: É um desafio controlar a disseminação de fenótipos críticos de resistência bacterianos. O predomínio de ESBL no referente hospital, assim como a ocorrência de genes codificadores de carbapenemases até então não relatados, ratificam a importância da vigilância epidemiológica e do incentivo a pesquisas subsequentes.

Impact of the beta-lacta test on the management of urinary tract infections at the emergency department

Introduction Rapid detection of extended-spectrum β-lactamases is essential. In this study, we evaluated the potential impact of β-lacta test on both the times to appropriate antibiotic therapy and to the implementation of patient isolation measures. Patients and methods We included prospectively all the patients admitted to the emergency department for clinical suspicion of urinary tract infection. Compared with physician’s decision, we analysed the potential impact of β-lacta test on the initial antibiotic therapy and on the implementation of hygiene measures. This study has been registered under number NCT02897609. Results We included 203 patients, 43% with acute pyelonephritis and 21% with acute prostatitis. The β-lacta test had a 95.2% sensitivity and a 99.5% specificity to detect extended-spectrum β-lactamases. Taking the β-lacta test results into account would have decreased significantly both the times to appropriate therapy and to isolation measures from 54 to 2.7 h and from 55.2 to 2.6 h, respectively. Conclusion The β-lacta test could reduce significantly the times to appropriate therapy and implementation of isolations measures.

Gram-negative bacteria carrying β-lactamase encoding genes in hospital and urban wastewater in Brazil.

Multidrug resistance mediated by β-lactamase in Gram-negative bacilli is a serious public health problem. Sewers are considered reservoirs of multiresistant bacteria due to presence of antibiotics that select them and favor their dissemination. The present study evaluated the antibiotic resistance profile and β-lactamases production in Gram-negative bacilli isolates from hospital sewage and urban wastewater treatment plants (UWWTP) in Brazil. Bacteria were isolated and identified with biochemical tests. Antibiotic susceptibility testing was performed by the disk-diffusion method and detection of extended-spectrum β-lactamase and carbapenemases by enzymatic inhibitor and conventional PCR. Differences in resistance to amoxicillin clavulanic, aztreonam, cefepime, and cefotaxime were observed in hospital sewage compared with urban sewage (p < 0.05). The multidrug-resistant phenotype was observed in 33.3% of hospital sewage isolates (p = 0.0025). β-lactamases genes were found in 35.6% of isolates, with the most frequent being blaKPC and blaTEM (17.8%), and blaSHV and blaCTX-M (13.3% and 8.9%, respectively). The data obtained are relevant, since the bacteria detected are on the priority pathogens list from the World Health Organization and hospital sewage could be released untreated into the municipal collection system, which may favor the spread of resistance. Changes in hospital sewage discharge practices, as well as additional technologies regarding effluent disinfection in the UWWTP, can prevent the spread of these bacteria into the environment and negative impact on water resources.

Neonatal sepsis due to ESBL producing Klebsiella

Neonatal sepsis due to ESBL producing Klebsiella - IJMR- Print ISSN No: - 2394-546X Online ISSN No:- 2394-5478 Article DOI No:- 10.18231/j.ijmr.2019.024, Indian Journal of Microbiology Research-Indian J Microbiol Res

Molecular typing, antibiotic resistance profiles and biocide susceptibility in Salmonella enterica serotypes isolated from raw chicken meat marketed in Venezuela.

Salmonella is a common bacterial cause of foodborne diarrhea worldwide. The purpose of this study was to characterize antimicrobial resistance and susceptibility to biocides in Salmonella enterica serotypes isolated from raw chicken meat, as well as to study the genetic relationship between strains and virulence profiles. Nine Salmonella enterica strains (5 S. Heidelberg; 2 S. Enteritidis; 1 S. Typhimurium and 1 S. Meleagridis) recovered from raw chicken meat marketed in the urban area of Mérida, Venezuela, were studied. Phenotypic characterization was based on antimicrobial susceptibility testing as well as detection of extended-spectrum β-lactamases (ESBLs) by double-disc synergy. The susceptibility to biocides was determined using the dilution-neutralization methods. The detection of quinolone resistance-determining regions of gyrA, gyrB, and parC genes, bla ESBLs genes, plasmid-mediated quinolone resistance determinants and virulence genes (invA and spvC) was carried out by PCR. All strains were typed using PFGE. Multidrug-resistance was evident in 6 of 9 strains studied. However, all Salmonella serotypes were susceptible to the tested biocides. Genotypic characterization determined that 5 strains harbored the bla CTXM-2, 4 bla TEM-1 and 3 qnrB19 genes. All strains were positive for the invA gene. The spvC gene was detected in 4 of them. PFGE grouped Salmonella strains into 4 different patterns that represented individual serotypes. This study provides valuable information on antibiotic resistance, biocide susceptibility profiles, virulence gene content and genetic diversity of Salmonella enterica serotypes isolated from raw chicken meat marketed in Venezuela, and evidenced a health risk for consumers.

Prevalence and Antibiotic Susceptibility Patterns of Salmonella and Shigella Species Isolated from Pediatric Diarrhea in Tehran

Background: Salmonella and Shigella infections are important public health concerns among children. The emergence of antibiotic resistance amongst Salmonella and particularly Shigella isolates has posed serious problems in antimicrobial treatment worldwide. Data on local antibiotic resistance patterns are essential to design suitable antibiotic treatment guidelines. Objectives: The aim of the present study was to determine the prevalence and drug susceptibility patterns of Shigella and Salmonella species in addition to the detection of extended-spectrum β-lactamase producing isolates among diarrhea samples of pediatric patients. Methods: A total of 5300 diarrheic samples from children were examined for the presence of Salmonella and Shigella species. Biochemical and microbial tests, as well as specific polyvalent antisera, were used for the identification of the bacterial species. Antibiotic susceptibility tests and extended-spectrum β-lactamase detection were conducted by disc diffusion and combination disc methods, respectively. Results: A total of 371 (7%) and 472 (8.9%) samples were positive for Salmonella and Shigella species, respectively. The most prevalent Salmonella isolate was serogroup D (n: 176, 47.5%). Of the Shigella isolates, 60.8% were found as Shigella sonnei and 39.2% as Shigella flexneri. The highest level of antibiotic resistance was noted among Shigella flexneri isolates. Overall, 35.7% of the Shigella flexneri isolates and 31% of the Shigella sonnei isolates produced extended-spectrum β-lactamases. Conclusions: This study provided information on the prevalence and antimicrobial susceptibility patterns of Salmonella and Shigella isolates in Iran. It also indicated a high-level resistance among Shigella isolates to co-trimoxazole and ampicillin and among Salmonella isolates to nalidixic acid.

ANTIMICROBIAL SUSCEPTIBILITY AND DETECTION METHODS FOR THE EXTENDED‑SPECTRUM β-LACTAMASES PRODUCING ENTEROBACTERIACEAE FROM CLINICAL SAMPLES

Objectives: Detection of extended-spectrum β-lactamases (ESBLs) is crucial for the infection control and antibiotic choice in healthcare settings. The aim of this study is to develop a standardized, inexpensive, and simple approach that is able to detect ESBL-producing Enterobacteriaceae isolates.Methods: Isolates those were resistant to at least one of the three indicator cephalosporins (cefotaxime, cefpodoxime, and ceftazidime) were tested for ESBL production using the double disc synergy test (DDST), combined disc synergy test (CDST) test and genotypic detection of the responsible gene for the ESBL.Result: From 64 isolates, 28 were resistant to cephalosporins. In 28 isolates, 23 were positive in CDST but in the DDST 18 were showing ESBL positive. 10 were positive in both CDST and DDST.Conclusion: Resistance to cephalosporins, which are the drug choice to treat mixed bacterial infections by the Enterobacteriaceae of which disseminate rapidly being plasmid mediated. Hence, it is necessary that rapid detection of ESBL should be done and immediate infection control measures should be implemented to prevent their dissemination.

Detection of extended-spectrum β-lactamase (ESBL) and plasmid-borne blaCTX-M and blaTEM genes among clinical strains of Escherichia coli isolated from patients in the north of Iran.

Escherichia coli is an important cause of hospital-acquired infections worldwide. Antimicrobial resistance leads to treatment failure of hospital infections caused by E. coli. Production of extended-spectrum β-lactamases (ESBLs) is one of the major causes of antibiotic resistance in these bacteria. This study aimed to investigate the frequency of blaTEM and blaCTX-M genes in ESBL-producing E. coli strains isolated from clinical specimens of patients admitted to six hospitals in the north of Iran. A total of 160 E. coli strains were isolated from various clinical samples of hospitalised patients. Antibiotic resistance patterns were determined by the Kirby-Bauer disk diffusion method. The double-disk phenotypic confirmatory test was carried out amongst β-lactam-resistant isolates to detect ESBL-producing strains. Plasmid DNA of ESBL-producing strains was extracted and subjected to PCR for detection of the blaTEM and blaCTX-M genes, and isolates were extensively verified by sequencing. The highest resistance rate was to amoxicillin; all E. coli isolates (100%) were susceptible to imipenem. Amongst the 160 clinical E. coli isolates, 83 (51.9%) were ESBL-positive, of which 27 (32.5%) and 72 (86.7%) were positive for blaTEM and blaCTX-M, respectively. This study is the first report of an ESBL phenotype disseminated in hospitals in the north of Iran. These findings showed that there was a direct relationship between the development of resistance to β-lactam antibiotics and production of TEM and CTX-M enzymes.

Epidemiology of Extended-Spectrum β-Lactamase-Producing Escherichia coli in the Human-Livestock Environment

The detection of extended-spectrum β-lactamase (ESBL) producers in the fecal flora of healthy food-producing animals has increased in recent years. This is mainly attributed to the intense use of antibiotics in this sector. There is growing concern regarding the risk of spread of such bacteria, especially Escherichia coli and Salmonella, to humans and to the environment. The occurrence of ESBL producers in the major groups of livestock, i.e., poultry, pigs, cattle, and sheep is highlighted and discussed with regard to data that provide evidence for transmission of their resistance traits from livestock to humans and to farm environments.

Extended Spectrum β-lactamase Detection and Antibiotic Susceptibility Profile of Staphylococcus aureus Strains Isolated from Surgical Wounds

Extended Spectrum β-lactamase Detection and Antibiotic Susceptibility Profile of Staphylococcus aureus Strains Isolated from Surgical Wounds

Extended-Spectrum β-Lactamase Enzymes (ESBLs) Produced by Escherichia coli Urinary Pathogens at Riyadh, Saudi Arabia

Background: This study aim was to determine the probable type of β-lactamase gene which is responsible for resistance. It was found that OXA (701 bp) was the main type of β-lactamase (35.7%), CTX-M (569 bp) was second (28.9%), TEM (403 bp) was third (20.5%) and SHV (293 bp) (14.9%) was fourth. The aim and objectives of this study were to investigate the prevalence of ESBLs producing in these bacteria isolated from uropathogenic out-patients and to look for the presence of TEM or SHV, CTX and OXA genes in E. coli. Results: The present study was carried out from the Central Laboratory of Riyadh Hospital in Saudi Arabia from January 2014 to June 2015. Total 116 urine samples were tested bacteriologically and for antibiotic susceptibility using standard procedures, Detection of extended-spectrum β-lactamases and determination of the genotype of β- lactamase of 75 E. coli isolates by PCR: It was found that OXA (701 bp) was the main type of β-lactamase (35.7%), CTX-M (569 bp) was second (28.9%), TEM (403 bp) was third (20.5%) and SHV (293 bp) (14.9%) was fourth. Conclusions: This study showed that the ESBL producing isolates detected PCR with oligonucleotide primers of TEM, SHV, and CTX-M and OXA genes and were carried out on E. coli DNA of 75 isolates. PCR, incorporating the primers for commonly prevalent ESBLs may be a valuable clinical and research tool for characterization of ESBLs

Genetic characterisation of multidrug-resistant Salmonella enterica serotypes isolated from poultry in Cairo, Egypt.

Food-borne diseases pose serious health problems, affecting public health and economic development worldwide. Salmonella was isolated from samples of chicken parts, skin samples of whole chicken carcasses, raw egg yolks, eggshells and chicken faeces. Resulting isolates were characterised by serogrouping, serotyping, antimicrobial susceptibility testing and detection of extended-spectrum β-lactamase (ESBL) production. Antibiotic resistance genes and integrons were identified by polymerase chain reaction (PCR). The detection rates of Salmonella were 60%, 64% and 62% in chicken parts, skin, and faeces, respectively, whereas the egg yolks and eggshells were uniformly negative. Salmonella Kentucky and S. Enteritidis serotypes comprised 43.6% and 2.6% of the isolates, respectively, whilst S. Typhimurium was absent. Variable resistance rates were observed against 16 antibiotics; 97% were resistant to sulfamethoxazole, 96% to nalidixic acid and tetracycline and 76% to ampicillin. Multidrug resistance was detected in 82% (64/78) of the isolates and ESBL production was detected in 8% (6/78). The β-lactamase blaTEM-1 gene was detected in 57.6% and blaSHV-1 in 6.8% of the isolates, whilst the blaOXA gene was absent. The sul1 gene was detected in 97.3% and the sul2 gene in 5.3% of the isolates. Sixty-four of the 78 isolates (82%) were positive for the integrase gene (int I) from class 1 integrons, whilst int II was absent. This study reveals the presence of an alarming number of multidrug-resistant Salmonella isolates in the local poultry markets in Cairo. The high levels of drug resistance suggest an emerging problem that could impact negatively on efforts to prevent and treat poultry and poultry-transmitted human diseases in Egypt.

Detection of Extended-Spectrum β-Lactamase and Plasmid-Mediated Quinolone Resistance Determinants in Escherichia coli Isolates from Retail Meat in China.

The aim of this study was to investigate the presence of extended-spectrum β-lactamase (ESBL) and plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli isolated from retail meat samples in Henan Province, China. E. coli isolates were detected in 179 of 645 (27.7%) retail meat samples. Resistance of these isolates to antimicrobials was commonly observed, with 78.2% of isolates resistant to streptomycin, 74.3% resistant to tetracycline and 54.2% resistant to trimethoprim/sulfamethoxazole. Of the 179 isolates, 30 (16.7%) expressed ESBL, with blaTEM-1 (n = 17) and bla(CTX-M-14) (n = 9) most commonly mediating the ESBL phenotype. PMQR genes were present in 14 isolates (7.8%), with qnr and aac(6')-Ib-cr detected alone or in combination in nine (5.0%) and seven isolates (3.9%), respectively. The qnr genes detected included qnrS1 (n = 5), qnrA1 (n = 3), and qnrB4 (n = 1). The qepA gene was absent among these isolates. CTX-M-14 was the most prevalent ESBL type among the PMQR-positive isolates. The qnr and aac(6')-Ib-cr genes were found to co-reside and be co-transferred with blaCTX-M-14 or blaTEM-1 in five isolates. Our data suggest that retail meat may act as a reservoir for multi-resistant E. coli and may facilitate the dissemination of resistance genes.