CTX-M Genes Research Articles

Detection of CTX-M-type ESBLs from Escherichia coli Clinical Isolates from a Tertiary Hospital, Malaysia

The present study aims to detect CTX-M-type ESBL from Escherichia coli clinical isolates and to analyze their antibotic susceptibility patterns. One hundred of E. coli isolates were collected from different clinical samples from a tertiary hospital. ESBL positivity was determined by the disk diffusion method. PCR used for amplification of CTX-M-type ESBL produced by E. coli. Out of 100 E. coli isolates, twenty-four isolates (24%) were ESBL-producers. E. coli isolated from pus was the most frequent clinical specimen that produced ESBL (41.66%) followed by urine (34.21%), respiratory (22.23%), and blood (19.05%). After PCR amplification of these 24 isolates, 10 (41.66%) isolates were found to possess CTX-M genes. The CTX-M type ESBL producing E. coli against antibiotics belonging to different families showed the highest resistance rates to Ampicillin (100%), Cefotaxime (97%), Cefuroxime (95%), and Ciprofoxacin (86%). Carbapenem groups of antibiotics, Meropenem (89%) and Imipenem (85%) have the highest susceptibility rate among all antibiotics used in this study. The outcome of the antimicrobial susceptibility testing of significant CTX-M- type ESBL producing E. coli could be useful to avoid failure or prolong treatments.

Accuracy of Nanosphere Verigene Gram-Negative Blood Culture (BC-GN) Test for Rapid Detection of Extended-Spectrum Beta-Lactamases (ESBLs) From Positive Blood Cultures

Abstract Background The rapid and accurate detection of ESBL production in Gram-negative rod (GNR) bacteremia is critical as recent data suggest that carbapenem treatment decreases mortality. At the same time, avoiding widespread empiric carbapenem prescribing is an important goal of antimicrobial stewardship teams. The aim of this retrospective review was to determine the accuracy of a nucleic acid–based test, Luminex Verigene BC-GN panel, to detect ESBL-positive GNRs direct from blood cultures. Methods The Verigene BC-GN was performed on all first positive GNR blood cultures. In addition, routine antibiotic susceptibility testing was performed on all isolates by the disk-diffusion method and included phenotypic ESBL testing using cefotaxime and ceftazidime with and without clavulanate. Escherichia coli, Klebsiella spp., and Proteus mirabilis–positive blood cultures were identified as ESBL producers through either Verigene or phenotypic disk testing. Positive GNR blood cultures from February 2016 to July 2017 were included for review. The primary objective was to determine the sensitivity and specificity of Verigene for detection of ESBLs. The secondary objective was assessing the percent of community-onset and hospital-acquired ESBL-positive blood cultures. Results There were 83 positive blood cultures with ESBL producing GNR included in the primary review. A total of 82 of 83 positive GNR blood cultures were CTX-M gene positive via Verigene (sensitivity 98.8%). All 83 cultures were confirmed as ESBL producers via phenotypic tests. There were no positive Verigene cases with negative phenotypic results. All 68 ESBL E coli–positive cultures were detected by Verigene (100%), 10 ESBL K pneumoniae (100%), and four of the five ESBL P mirabilis–positive cultures (80%). Of the 73 results available for review in the secondary objectives, 68 were community onset (93%) and five were hospital acquired (7%). Conclusion The majority of ESBL-positive blood cultures in a low-prevalence setting were due to CTX-M producers. The Luminex Verigene BC-GN was accurate in detecting ESBL-producing Enterobacteriaceae from blood cultures and can be reliably used to guide antimicrobial therapy.

Genotypic detection of extended spectrum beta lactamases from selected bacterial isolates in the Specialist Hospital Sokoto, Nigeria

There are numerous reported cases of extended spectrum beta lactamases (ESBLs) producing Enterobacteriaceae in Nigeria, with little effort done on the molecular detection. Epidemiological studies around the world have investigated the prevalence of ESBL-producing enterobacteriaceae and they have seen multiple mechanisms of drug-resistance. Our study was designed to detect ESBLs genes such as CTX-M, SHV, and TEM using PCR from clinical isolates in a tertiary hospital in Sokoto metropolis. Clinical isolates from the Microbiology laboratory of the tertiary hospital was collected for 3 months. These isolates were identified using standard microbiological methods. They were tested against 8 antibiotics using the modified Kirby Bauer disc diffusion method. Multidrug resistant isolates were screened for ESBL production, and further confirmed by the Double Disc Synergy Test (DDST). Genotypic confirmation was carried out using multiplex Polymerase Chain Reaction (PCR). A total of 47 isolates made up of 21 E. coli (44.6%), 13 Klebsiella spp (27.6%), 7 Salmonella spp (14.9%), 5 Proteus mirabilis (10.6%), and 1 Enterobacter spp (2.1%) were obtained from urine, stool, and wound swab. Out of the 47 isolates, (45) 95.7% were multidrug resistant. Twenty-five (53.2%) were potential ESBL producers, while only 5 (20.0%) were confirmed phenotypically using a DDST. PCR results revealed 4 out of 5 of the isolates were possessing ESBL genes. It also revealed that 3 isolates co-produce TEM and SHV at 403bp and 293bp respectively. Only 1 isolate produced CTX-M gene at 569bp. The prevalence of ESBL production in the Gram negative enterobacteriaceae in our study did not indicate a high prevalence as reported by some studies in Sokoto and Northwest Nigeria.Keywords: Molecular detection, ESBLs, Clinical isolates, PCR

Multi locus sequence typing and antibiotic susceptibility of extended-spectrum beta-lactamases producing Enterobacteriaceae in rural residents in villages with pig-breeding farms in Shandong province

Objective: To analyze the antimicrobial resistance and multilocus sequence typing (MLST) results of extended-spectrum β-lactamase (ESBLs)-producing Escherichia coli in rural residents in villages with pig breeding farms in a county of Shandong province. Methods: Antimicrobial susceptibility testing was performed with agar dilution method by using 360 ESBLs-producing E. coli strains from fresh stool samples of rural residents in villages with pig breeding farms in a county of Shandong. PCR was conducted to amplify the CTX-M, TEM, SHV genes and capillary electrophoresis was used to screen positive strains in July, 2016. MLST was performed for molecular typing analysis, and eBURST v3.0 software was used for cluster analysis. Results: Among 360 strains of ESBLs-producing E. coli, the resistance rates to cefotaxime, tetracycline, trimethoprim-sulfamethoxazole and florfenicol were 100.0% (360/360), 82.2% (296/360), 81.1% (292/360) and 80.3% (289/360), respectively. The positive rate of CTX-M gene was 99.2% (357/360), in which the positive rate of CTX-M-9 was 35.6% (128/360) and the positive rate of CTX-M-1 was 24.4% (88/360). The positive rate of TEM gene was 26.9% (97/360). A total of 132 STs were identified through MLST. The predominant ST was ST10, accounting for 12.5% (45/360). Cluster analysis showed that CC10 was the most important clone group, including 39 ST clones, involving 148 strains (41.1%). Conclusions: The drug resistances of ESBLs-producing E. coli to cefotaxime, tetracycline, trimethoprim-sulfamethoxazole and flurfenicol are serious in this rural area. There is a small-scale clustering of CC10 and transmission mode from animals to humans might exist.

Urban brown rats (Rattus norvegicus) as possible source of multidrug-resistant Enterobacteriaceae and meticillin-resistant Staphylococcus spp., Vienna, Austria, 2016 and 2017.

BackgroundBrown rats (Rattus norvegicus) are an important wildlife species in cities, where they live in close proximity to humans. However, few studies have investigated their role as reservoir of antimicrobial-resistant bacteria.AimWe intended to determine whether urban rats at two highly frequented sites in Vienna, Austria, carry extended-spectrum β-lactamase-producing Enterobacteriaceae, fluoroquinolone-resistant Enterobacteriaceae and meticillin-resistant (MR) Staphylococcus spp. (MRS).MethodsWe surveyed the presence of antimicrobial resistance in 62 urban brown rats captured in 2016 and 2017 in Vienna, Austria. Intestinal and nasopharyngeal samples were cultured on selective media. We characterised the isolates and their antimicrobial properties using microbiological and genetic methods including disk diffusion, microarray analysis, sequencing, and detection and characterisation of plasmids.ResultsEight multidrug-resistant Escherichia coli and two extensively drug-resistant New Delhi metallo-β-lactamases-1 (NDM-1)-producing Enterobacter xiangfangensis ST114 (En. cloacae complex) were isolated from nine of 62 rats. Nine Enterobacteriaceae isolates harboured the bla CTX-M gene and one carried a plasmid-encoded ampC gene (bla CMY-2). Forty-four MRS were isolated from 37 rats; they belonged to seven different staphylococcal species: S. fleurettii, S. sciuri, S. aureus, S. pseudintermedius, S. epidermidis, S. haemolyticus (all mecA-positive) and mecC-positive S. xylosus.ConclusionOur findings suggest that brown rats in cities are a potential source of multidrug-resistant bacteria, including carbapenem-resistant En. xiangfangensis ST114. Considering the increasing worldwide urbanisation, rodent control remains an important priority for health in modern cities.

High Genetic Diversity of Enterobacteriaceae Clones and Plasmids Disseminating Resistance to Extended-Spectrum Cephalosporins and Colistin in Healthy Chicken in Tunisia.

Enterobacteriaceae resistant to extended-spectrum cephalosporins (ESC-R) are listed as "priority pathogens" by the World Health Organization, and the Agri-food sector has regularly been pointed out as a potential source of ESC-R for humans through food consumption and animal handling. Chicken industry and chicken meat have recurrently been under specific scrutiny due to the high proportions of ESC-R reported worldwide in this sector. In Tunisia, recent studies suggested that the plasmidic AmpC blaCMY-2 gene may have emerged in chicken. We thus collected 258 cloacal swabs from five different farms and selected ESC-R isolates to determine the current ESC-R prevalence and epidemiology. All five farms were ESC-R positive with proportions ranging from 4% to 67.3%. blaCTX-M-1/IncI1/ST3 was the dominant gene/plasmid association in chicken, but several other CTX-M genes and plasmid backgrounds were shown to spread ESC-R. Surprisingly, the CMY-2 enzyme was only identified in one isolate. In addition, we also reported the sporadic presence of the mcr-1 gene carried by an IncHI2 plasmid. Our data suggest that the high diversity of Enterobacteriaceae clones and plasmids circulating in healthy chicken in Tunisia maintains a high ESC-R proportion in flocks and constitutes a major source of ESC-R determinants further disseminating in the food chain.

Assessment of SHV, CTX-M, and IMP Genes in Beta-Lactam-Resistant Escherichia coli Isolated from Patients with Urinary Tract Infection

Objectives: Escherichia coli are resistant to β-lactam antibiotics due to the acquisition of plasmids that encode broad-spectrum β-lactamases. Extended-spectrum β-lactamases (ESBLs) have particular importance in antimicrobial therapy. The current study aimed at determining the frequency and role of SHV, CTX-M, and IMP genes in resistance to ceftriaxone, imipenem, and piperacillin antibiotics in E. coli isolated from patients with urinary tract infection (UTI). Methods: The study population included outpatients and inpatients of two genders in all ages with UTI. A total of 270 non-duplicate E. coli stains producing ESBL from Velayat Hospital, Damghan city, Semnan province, Iran were isolated using screening and double-disc phenotypic test. All isolates were screened to detect SHV, CTX-M, and IMP genes using polymerase chain reaction (PCR). Results: In total, 120 (44.4%) samples were positive for ESBLs including 30% CTX-M, 27.5% SHV, and 0% IMP genes. The obtained results showed that the responses of male and female patients to the examined antibiotic were different. The distribution of underlying diseases (diabetes, kidney stones, obstructive disease, congenital anomalies, and hospitalization history) was different in patients with UTI. It was observed that after hospitalization history, diabetes had the highest frequency in female (31.08%) and male (27.59%) patients with UTI. Conclusions: However, bacterial strains producing ESBLs such as E. coli should be considered as a major threat to public health due to the risk of resistant to broad-spectrum cephalosporins. Therefore, to prevent resistance to antibiotics, indiscriminate administration of such agents should be avoided.

Molecular Detection ctx-M, TEM and VIM in ESBL-Producing E. coli Strains Isolated from Pregnant Women in Osogbo

Urinary tract infection (UTI) is a major bacterial infection causing serious health problem in pregnant women. The physiological and anatomical changes in pregnancy facilitate urinary tract infection (UTI) during pregnancy. Asymptomatic bacteriuria in pregnancy is associated with pyelonephritis, preterm labour and low birth weight infants. The study was designed to characterise phenotypically and genetically the major organism associated with UTI among pregnant women in Osun State. A cross-sectional study design was used to collect mid-stream urine samples between March 2018 to September 2018 from 150 pregnant and 50 non-pregnant women which serve as control. Samples were inoculated into Cysteine Lactose Electrolyte Deficient (CLED) medium, subcultured onto MacConkey and Blood agar plates. A standard agar disc diffusion method was used to determine antimicrobial susceptibility pattern of the isolates and the molecular detection of the antibiotic resistant genes were done. Data were subjected to descriptive statistics. The ages of women enrolled in this study ranges from 22 to 43 years (mean ± standard deviation = 25 ± 4.7 years). The predominant bacteria identified were E. coli (34.5%), S. aureus (10.3%), coagulase negative Staphylococci [CoNS] (17.2%), Klebsiella species (6.9%) and Enterobacter species (31.0%). Majority of Gram-negative bacteria isolates were resistant to ampicillin (70%), cefotaxime (62%), while 75–100% of the Gram positive isolates were resistant to ampicillin. Multiple drug resistance was observed, all the E. coli isolates were resistant to Cefotaxime, meropenem and ampicillin. Of E. coli isolates, 4, 3 and 6 were positive for the VIM, ctx-M and TEM genes respectively.Similarly, the risk of UTI was higher in those had previous UTI history (OR = 2.29, 95% CI = 1.15–4.56, P = 0.019) as compared to those who had no previous history of UTI.

Detection and genetic characterization of extended-spectrum beta-lactamases producers in a tertiary care hospital.

BACKGROUND:Extended-spectrum beta-lactamase (ESBL)-producing organisms inactivate extended beta-lactam antibiotics and monobactams and also exhibit coresistance to many other classes of antibiotics. The present study was carried out to assess the prevalence of the ESBLs and to determine the most prevalent genotype in our hospital.MATERIALS AND METHODS:All clinically significant Gram-negative isolates were identified, and their antimicrobial susceptibility testing was done by Kirby–Bauers' disc diffusion method. ESBL detection was confirmed by minimal inhibitory concentration method using agar dilution technique for those who screened positive by ceftazidime (30 μg) disc. Further, the established ESBL-positive isolates were subjected to genotyping for bla TEM, bla CTX-M, and bla SHV genes by using conventional polymerase chain reaction.RESULTS:Escherichia coli was the most common (28.84%) Gram-negative bacillus followed by Klebsiella pneumoniae (18.07%), while Pseudomonas spp. (9.61%) was the most commonly identified nonfermenter. ESBL production was detected in 160 (30.8%) isolates. Klebsiella oxytoca (46.7%) followed by E. coli (44%) were the common ESBL producers. Most predominant ESBL gene was bla TEM, found in 122 (76.25%) isolates. Combinations of two genes were seen in 109 (68.1%) isolates, the most common (43.12%) combination being blaTEM and blaCTX-M. In this study, 16 (10%) strains had all the three types of genes. Most of the isolated Gram-negative bacilli (GNB) were sensitive to amikacin, imipenem, and colistin.CONCLUSION:In our study, the 30.8% of GNB were ESBL producers. This is the only study that shows that TEM is the most prevalent ESBL genotypes in our area. Of concern is a good number of isolates showing all three patterns of genes (TEM, SHV, and CTX-M). Amikacin, imipenem, and colistin were the most useful antibiotics in our setup.

Evaluating Dissemination Mechanisms of Antibiotic-Resistant Bacteria in Rural Environments in China by Using CTX-M-Producing Escherichia coli as an Indicator.

It is becoming increasingly recognized that the environment plays an important role both in the emergence and in dissemination of antibiotic-resistant bacteria (ARB), Mechanisms and factors facilitating this development are, however, not yet well understood. The high detection rate of CTX-M genes in environmental sources provides an opportunity to explore this issue. In this study, 88 CTX-M-producing Escherichia coli were isolated from 30 pig feces samples from 30 pig farms and 201 environmental samples. CTX-M-producing E. coli was detected with the following frequencies in the different types of samples: pig feces, 73%; river water, 64%; river sediment, 52%; wastewater, 31%; drinking water, 23%; outlet sediment, 21%; soil, 17%; and vegetables, 4.4%. Dissemination of CTX-M-producing E. coli to different environmental matrices was evaluated by analyzing the genetic relatedness of isolates from different environmental sources, and putative transmission routes through bird feces, pig feces, drinking water, river sediment, river water, and wastewater were hypothesized. Dissemination through these routes is likely facilitated by anthropogenic activities and environmental factors. Wild birds as potential vectors for dissemination of CTX-M-producing E. coli have the capacity to spread ARB across long distances. Regional dissemination between different environmental matrices of CTX-M-producing E. coli increases the exposure risk of humans and animals in the area.

A Machine Learning-based Pipeline for the Classification of CTX-M in Metagenomics Samples

Bacterial infections are a major global concern, since they can lead to public health problems. To address this issue, bioinformatics contributes extensively with the analysis and interpretation of in silico data by enabling to genetically characterize different individuals/strains, such as in bacteria. However, the growing volume of metagenomic data requires new infrastructure, technologies, and methodologies that support the analysis and prediction of this information from a clinical point of view, as intended in this work. On the other hand, distributed computational environments allow the management of these large volumes of data, due to significant advances in processing architectures, such as multicore CPU (Central Process Unit) and GPGPU (General Propose Graphics Process Unit). For this purpose, we developed a bioinformatics workflow based on filtered metagenomic data with Duk tool. Data formatting was done through Emboss software and a prototype of a workflow. A pipeline was also designed and implemented in bash script based on machine learning. Further, Python 3 programming language was used to normalize the training data of the artificial neural network, which was implemented in the TensorFlow framework, and its behavior was visualized in TensorBoard. Finally, the values from the initial bioinformatics process and the data generated during the parameterization and optimization of the Artificial Neural Network are presented and validated based on the most optimal result for the identification of the CTX-M gene group.

Synergistic evaluation of AgO2 nanoparticles with ceftriaxone against CTXM and blaSHV genes positive ESBL producing clinical strains of Uro-pathogenic E. coli.

The silver oxide nanoparticles (AgO2-NPs) were synthesised using silver foil as a new precursor in wet chemical method. X-ray diffraction analysis shows crystallographic structures of AgO2-NPs with crystallite size of 35.54 nm well-matched with standard cubic structure. Scanning electron microscopy analysis clearly shows the random distribution of spherical-shaped nanoparticles. Energy dispersive X-ray analysis confirmed the purity of the samples as it shows no impurity element. Fourier transforms infra-red analysis confirmed the formation of AgO2-NPs with the presence of Ag-O-Ag stretching bond. All the techniques also confirmed the loading of ceftriaxone drug on the surface of AgO2-NPs. This study also described the effect of AgO2-NPs having synergistic activity with β lactam antibiotic i.e. ceftriaxone against ESBL generating Escherichia coli (E. coli). Among isolated strains of E. coli, 60.0% were found to be ESBL producer. The synergistic activities of AgO2-NPs with ceftriaxone suggest that these combinations are effective against MDR-ESBL E. coli strains as evident by increase in zone sizes. The present study observed rise in MDR-ESBL E. coli with polymorphism of blaCTXM and blaSHV causing UTI infections in Pakistani population. The antibiotic and AgO2-NPs synergistic effect can be used as an efficient approach to combat uro-pathogenic infections.

Antibiotic resistance profile and co-production of extended spectrum beta lactamases and AmpC in Acinetobacter spp. in a level 1 trauma center from India.

INTRODUCTION:Acinetobacter baumannii has now emerged as a significant nosocomial pathogen in health-care setting ESP in intensive care units. Rapidly growing resistance among clinical isolates suggests a need to detect resistance mechanisms in this organism. The present study was designed to compare the various phenotypic tests available with the gold standard of genotype.METHODOLOGY:The present study was conducted to include all isolates of Acinetobacter spp. isolated over 3 years. Their resistance to various antibiotics was determined and extended spectrum beta-lactamases (ESBL) and AmpC production in the isolates showing resistance to ceftazidime/ceftriaxone/cefotaxime (CAZ/CTR/CTX) was determined. ESBL and AmpC production was confirmed using polymerase chain reaction (PCR).RESULTS:A total of 154 strains were isolated, and all the strains were tested for ESBL and AmpC detection. Of the strains tested, 15 (9.7%), 17 (11%), 24 (15.6%), 27 (17.5%), 54 (35%), 67 (43.5%), and 72 (46.7%) strains showed ESBL production using CTX/CTX-clavulanate double-disc synergy test (DDST), CTX/CTX-clavulanate E-test, CAZ/CAZ-clavulanate DDST, CAZ/CAZ-clavulanate E-test, Piperacillin/Piperacillin-tazobactam (TZ) DDST, CTR/CTR-Sulbactum DDST, and Piperacillin/Piperacillin-TZ E-test, respectively. 20 (12.9%) and 19 (12.3%) of strains were positive for AmpC production using AmpC disc test and Boronic acid inhibition test, respectively. Genotype analysis using PCR for TEM, SHV, CTXM, PER, and VEB genes was done and 69 (51.5%) strains were positive for TEM gene.DISCUSSION:ESBL detection in Acinetobacter spp. is difficult as standard guidelines for the same are not available unlike in enterobacteriaceae, and there are no zone diameter breakpoints for aztreonam and cefpodoxime. In comparison, piperacillin/piperacillin-TZ E-test had the best sensitivity and specificity for ESBL detection.CONCLUSION:Standard guidelines for ESBL detection in nil fermeners like Acinetobacter spp. must be laid down for ease of detection. Use of piperacillin/piperacillin-tazobactam E-test could be used as one of the standard methods.

CTX-M Β-LACTAMASE–PRODUCING ESCHERICHIA COLI IN SUDAN TERTIARY HOSPITALS: DETECTION GENOTYPES VARIANTS AND BIOINFORMATICS ANALYSIS

Background: Extended spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) constitute an emerging public-health concern. Consider that ESBL genes type CTX-M types has been increased significantly in most parts of the world. Few data are available on the CTX-M variants circulating in Sudan. Objective: This study used polymerase chain reaction (PCR) and bioinformatics tools to identify blaCTX-M and its variants for Extended-spectrum β-lactamase (ESBLs) producing clinical isolates of Escherichia coli (E. coli) obtained from hospitals in Khartoum-Sudan. Methods: A total of 216 non-repetitive isolates were selected during 2007-2018. The phenotypic identification of ESBL production was confirmed according to CLSI guidelines. CTX-M genotype was analyzed by uniplex PCRs reactions subsequently sequences performed later sequences were analyzed using bioinformatics tools with nBLAST program, multiple alignments to determine CTX-M genotype variants . Nucleotide sequences were submitted to Gen Bank and accession numbers were obtained. Result: ESBL phenotype among 212 confirmed E.coli isolates was (34.9% of 212,n=74). (62.2% of 74, n=46) strains carried bla CTX-M genes, CTX-M genotype variants identified in this study as followed: blaCTX-M-15 gene was the most prevalent one (78.6%) followed by blaCTX 90 (14.3%) and CTX-M55 (7.1%),
 Conclusion: This study reveled high ESBL occurrence among E.coli isolates, with CTX-M 15 the predominant variants and highlights the incidence of CTX-M-55 for the first time from Sudan.
 Keywords: E. coli, PCR, ESBLs, CTX-M, Sudan, bioinformatics

Molecular-diversity, Prevalence and Antibiotic Susceptibility of Pathogenic Klebsiella Pneumoniae under Saudi Condition.

Klebsiella pneumoniae is an important multi-drug-resistant Gram-negative pathogen, associated with nosocomially acquired infections. This study aimed to determine the genotypic and phenotypic characterization of Klebsiella pneumoniae isolates and to correlate the antibiotic resistance with the presence of virulence genes revealed by molecular genotypic testing in Riyadh, Saudi Arabia. About 23 Klebsiella pneumoniae isolates were collected from various specimen types. Identification of the organisms was carried out. Antimicrobial susceptibility performed against 12 antibiotics. The DNA was isolated and purified then genotypic confirmation was done through polymerase chain reactions (PCR) to detect TEM, SHV, CTX-M, IMP and KPC genes. PCR products were sequenced and aligned with GenBank sequences. Out of 23 isolates of K. pneumoniae, the majority (43.5%) was from tracheal aspirate. The percentage of females (65.2%) was more than males (34.8%). The highest isolates prevalence was found in the age group of >58 (39.1%). About 100% of isolates were resistant to cefotaxime, ceftriaxone, ceftazidime, cefepime and ampicillin and 91.3% were sensitive to amikacin and Imipenem. Most isolates were SHV-9 gene positive (52.2%). It was found that tested isolates had 99-100% similarity when compared to GenBank sequences. There was a preponderance of SHV-9 gene which suggests dissemination of the gene in the tested isolates.

Detection of SHV, CTX-M and TEM genes in extended spectrum beta lactamase producing multi-drug resistant Escherichia coli from clinical isolates in Calabar, Nigeria

Background The emergence of multi-drug resistant strains of Escherichia coli complicates the treatment of infections. The detection of ESBL genes in bacteria and their antimicrobial resistance patterns can provide information about their epidemiology and transmission. The study aimed to detect ESBL genes that encode; CTX-M, TEM and SHV in E. coli isolatesin our locality. Methods Clinical E. coli isolates were obtained from public and private clinics within Calabar metropolis. Biochemical method was used to re-identify the isolates. Antibiotics susceptibility testing was done using Kirby-Bauer disc diffusion method. Phenotypic detection of ESBL in isolates was done by double disc synergy test (DDST). The ESBL genes were detected using conventional PCR method. Results The ESBL phenotypic positive isolates was (56.6 %). The most prevalent gene in the study was CTX-M gene. Antibiotic susceptibility of E. coli isolates to commonly used antibiotics was low. Isolates were most susceptible to quinolones (54.7 %) and fluoroquinolones (34.0 %). The ESBL producing isolates were more susceptible to quinolones but less susceptible to the third generation cephalosporins. There was significant association between gene expression by isolates and antibiotic resistance (P≤0.05). Isolates with the SHV and TEM genes showed 100 % resistance to some tested antibiotics. Isolates with CTX-M genes were also highly resistant. Conclusion The SHV, CTX-M and TEM genes were detected in Escherichia coli isolates in our locality. These may have resulted in the high resistance of isolates to commonly used antibiotics which may pose challenges to patient’s management.

Prevalence of extended spectrum beta-lactamase producing Enterobacteriaceae in urine samples from Thumbay hospitals, U.A.E

Beta Lactamases is proven to be one of the leading cause of resistance to β-lactam antibiotics among gram-negative bacteria. Many up to date researches have shown increase in the incidence and prevalence of ESBL worldwide. This study aimed to determine the prevalence of ESBL strains of Klebsiella spp. and Escherichia coli species in urinary isolates from the patients admitted in Thumbay hospitals around United Arab Emirates. Furthermore, drug resistant genes (SHV and CTX-M) in the ESBL positive samples were detected. 237 urine samples were collected from November 2017 to January 2018. Based on the lactose utilization, colony morphology, and biochemical utilization of the gram negative bacilli were identified as E. coli (53), Klebsiella pneumoniae (10) and Citrobacter species (2). Antibiotic sensitivity test, double disc diffusion test and combination disc tests all confirmed that the 65 (27.4 %) out of 237 isolates were ESBL producing bacteria. There was high prevalence of bacteria in females than male and the number of E. coli strains is higher than Klebsiella spp. DNA isolation was performed on the 65 samples, out of which 50 samples were selected for PCR based on their concentration. The selected DNA samples were used to detect the presence of bla CTX-M and bla SHV genes. Only 24 DNA samples (48 %) contains blaCTX-M genes, bla SHV or both the genes. 14 samples had bla CTX-M gene, 2 bla SHV genes, and 8 with both bla SHV and bla CTX-M. At the rate at which ESBL is spreading, further research, close observation and cautious use of antibiotics is important.

Determination of Antibiotic Resistance Pattern and frequency of CTX-M, TEM, and SHV Β-Lactamase Encoding Genes among Shigella Isolates from Inpatients in Tehran, Iran

Determination of Antibiotic Resistance Pattern and frequency of CTX-M, TEM, and SHV Β-Lactamase Encoding Genes among Shigella Isolates from Inpatients in Tehran, Iran

Phenotypic and Genotypic Characterization of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Asymptomatic Bacteriuria in Pregnancy.

Asymptomatic bacteriuria (ASB) has been consistently observed in pregnancy. However, there is a paucity of data on the prevalence and characteristics of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in ASB in pregnant women. Therefore, we sought to investigate ESBL-producing and multidrug-resistant Enterobacteriaceae in antenatal women with ASB. Urine samples were collected from 310 asymptomatic pregnant women attending primary antenatal clinics and screened for significant bacteriuria. Isolates of Enterobacteriaceae were phenotypically tested for their ESBL production. ESBL genes (CTX-M, TEM, and SHV genes) were then amplified by polymerase chain reaction (PCR). Multiplex PCRs were used to perform phylogenetic typing of ESBL-producing Escherichia coli isolates and to examine the commonality of sequence type 131 (ST131)-O25b and ST131-O16. A total of 103 (33.2%) pregnant women were positive for significant bacteriuria (80 Enterobacteriaceae). Of these isolates, 32.5% (n = 26) were ESBL producers and had a higher rate of multidrug resistance than non-ESBL producers. Genotypic characterization of ESBL-producing isolates showed that 84.6% had the blaCTX-M gene (blaCTX-M-15 = 77.3%; blaCTX-M-9 = 18.2%). None of the isolates were of the TEM or SHV type. Half of the ESBL-producing E. coli isolates were of the phylogroup B2, and 4 (20%) isolates were of the ST131-O16 clonal subgroup. This study is the first in Egypt to provide evidence for the high prevalence of ESBL-producing Enterobacteriaceae in pregnant women with ASB. It also represents an important step toward genotypic characterization of this resistant form of bacteria, which may be useful for future antimicrobial studies.

CTX-M type extended-spectrum β-lactamase in Escherichia coli isolated from extra-intestinal infections in a tertiary care hospital in south India.

Background & objectives:Infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli carrying blaCTX-M genes have been spreading globally, but there are geographical variations in the type of blaCTX-M genes prevalent and there are scanty data from India. This study was conducted to determine the CTX-M type ESBLs in E. coli isolates obtained from clinical specimens from patients with extra-intestinal infections attending a tertiary care hospital in south India.Methods:ESBL-producing E. coli isolated from patients with extra-intestinal infections were subjected to PCR using CTX-M group-specific primers. From a representative isolate, full-length CTX-M-15 gene was amplified and sequenced. An internal fragment of this gene was sequenced in 10 representative isolates.Results:Of the 300 isolates of E. coli tested, 88 per cent carried CTX-M genes and blaCTX-M-15 was the most dominant gene present in 90 per cent of the positive isolates. Most (91%) of the isolates positive for blaCTX-M were sensitive to meropenem.Interpretation & conclusions:Our findings showed blaCTX-M-15 to be the dominant gene. Based on the data on antimicrobial susceptibility, cefoperazone-sulbactum could be an antimicrobial of choice.