ESBL Producers Research Articles

Phenotypic, genotypic characterization and antimicrobial resistance profiling of uropathogenic Escherichia coli in a tertiary care hospital, Puducherry, India

Background and Objectives: Uropathogenic Escherichia coli (E. coli) (UPEC) accounts for 70-95% of community-ac- quired urinary tract infections (UTIs) and a significant proportion of nosocomial UTIs. This study aimed to characterize the phenotypic and genotypic characteristics of E. coli isolates from symptomatic UTI patients and evaluate their antimicrobial susceptibility patterns. Materials and Methods: A hospital-based observational study was conducted at Aarupadai Veedu Medical College and Hospital, Puducherry, India, from August 2022 to April 2024. A total of 106 UPEC isolates were obtained from symptomatic UTI patients. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer method, and virulence genes (hlyA, fimH, papC) were detected using PCR. Results: The mean age of patients was 49.7 years, with a female predominance (69.8%). Diabetes mellitus was the most common comorbidity (29.2%). Fever (60.4%) and dysuria (38.7%) were the most common symptoms. AST showed high susceptibility (>90%) to amikacin, nitrofurantoin, meropenem, and piperacillin/tazobactam, while >60% resistance was ob- served to cefotaxime and ceftazidime. Phenotypically, 30.2% of the isolates produced mannose-resistant hemagglutinins, and 17.9% produced hemolysin. ESBL production was found in 46.3%. Biofilm production was moderate in 65.1%, weak in 30.2% and strong in 4.7% and significantly correlated with multidrug resistance (p<0.05). Genotypically, 80.2% had fimH, 51.9% had papC and 20.8% had hlyA. papC was associated with reduced cefotaxime susceptibility (p<0.05). Conclusion: The study highlights the significance of phenotypic and genotypic characterization in understanding UPEC virulence and resistance patterns, and emphasizes the need for targeted empiric therapy to improve UTI management.

Unraveling gut gram-negative antibiotic-resistant colonization dynamics in hematologic cancers: Insights from bioinformatics and immune signatures.

10031 Background: Infections account for ~60% of cancer-related deaths. Hematologic cancers have a 3x higher infection-related mortality than solid tumors, with resistant Gram-negative (GN) bacteria causing ~50% of bloodstream infections, highlighting the need to study the microbiome, antibiotic resistance, and infection risks. Methods: Stool samples from newly diagnosed hematologic cancer patients were collected at baseline, post-chemotherapy, and subsequent admission at Amir Hospital, a referral cancer center in southern Iran, to analyze microbial colonization dynamics. Patients enrolled in a 16-month observational program to investigate the correlation between clinical factors and infectious outcomes. Carbapenem-resistant and ESBL-producing were cultured on MacConkey agar with meropenem and ceftriaxone. ESBL and carbapenemase production assessed adhering to CLSI guidelines. To support our findings, we used the microbioTA database to identify highly elevated 16S rRNA expression in blood and lymph nodes of hematologic cancer patients, exploring microbiome-host interactions worldwide. We used gutMgene, GIMICA, and AMIDIS databases to explore key microbe-immune factor associations trough network centrality analysis of the immune factors. Central factors further examined in the Amir Cancer Registry datasets to assess their association with infectious events. STATA v27 used for statistical analyses. Results: Among 73 pediatric patients, GN drug-resistant bacteria was detected in 51 before hospitalization. Escherichia coli (86.6% of positive samples) and Klebsiella pneumoniae (9.5%) were the predominant pathogens. Drug-resistant E. coli persisted across samples, indicating gut colonization, consistent with microbioTA data showing E. coli detection at baseline and post-induction therapy. ESBL and carbapenemase-producing strains were 56.8% and 15.8%. Colonized patients had a 13.8% mortality rate, with bloodstream infections and typhlitis more common in K. pneumoniae and carbapenem-resistant strains. Previous antibiotic exposure, malignancy relapse, and colonization status were risk factors for mortality and infection. Investigation of the microbioTA database identified 10 datasets from Asia, Europe, and America revealed the detection of Bacillus cereus in 9 datasets, followed by E.coli (8) and Enterobacterales like Salmonella enterica (5) and K.pneumoniae (3), approving the high impact of E.coli worldwide. IL-4, IL-6, and TNF-α showed high centrality, with retrospective analysis linking their upregulated serum baseline levels to infection outcomes in Amir hospital datasets. Conclusions: Our study links GN microbial colonization, traced by elevated immune markers, to infectious complications, highlighting the need for microbiota-specific diagnostic and treatment protocols.

Plasmid mediated colistin resistance in ESBL producing Enterobacterales based on both phenotypic and molecular analysis in companion and farm animals from Algeria.

Plasmid mediated colistin resistance in ESBL producing Enterobacterales based on both phenotypic and molecular analysis in companion and farm animals from Algeria.

Prevalence and antibiotic resistance in Escherichia coli strains isolated from poultry farms in Azaguie, Côte d'Ivoire

Poultry farming, a promising sector in Côte d'Ivoire, is faced with a number of infectious diseases that are causing heavy losses at various stages of the value chain. The aim of this study is to determine the antibiotic resistance profile of Escherichia coli strains circulating in broiler farms in Azaguié, a locality in the south of Côte d'Ivoire. The methods used are isolation and phenotypic identification, antibiogram for bacterial sensitivity and synergy test for the production of extended-spectrum beta-lactamase. Fifty-seven (57) strains of Escherichia coli were isolated from droppings from 14 broiler farms in Azaguié. The study of bacterial sensitivity showed high rates of resistance to amoxicilin + clavulanic acid (48.48%), ceftazidime (21.21%), gentamicin (60.61%), colistin (100%) and nalidixic acid (57.57%). However, low levels of resistance were obtained with Cefotaxime and Ceftriaxone, with a rate of 6.06%. These results show the importance of raising awareness among poultry farmers about the use of antibiotics in order to reduce the level of antimicrobial resistance in this region.

Characterization of antimicrobial resistance among Proteus mirabilis isolates from catheter-associated urinary tract infections and non-catheter-associated urinary tract infections in Egypt

BackgroundRecent worldwide reports of increased numbers of multidrug-resistant (MDR) Proteus mirabilis (P. mirabilis) isolates, particularly those producing extended-spectrum β-lactamases (ESBLs), are alarming. P. mirabilis is a common causative agent of complicated urinary tract infections (UTIs), particularly in patients with long-term urinary catheterization. This study aimed to assess the prevalence, antibiotic resistance patterns, and determinants of P. mirabilis among catheter-associated UTIs (CAUTI) and non-catheter-associated UTIs (non-CAUTI).MethodsOne hundred and three Proteus strains isolated from 613 UTI patients in Minia, Egypt, were examined for antibiotic resistance patterns, ESBL production, and sulphonamide resistance phenotypically. Class 1 and 2 integrons, ESBL, and sul resistance genes were detected by Polymerase chain reaction (PCR), followed by molecular typing of ESBL-producing isolates from catheterized UTI patients using ERIC-PCR.ResultsProteus isolates were detected in 20% of the UTIs, with a higher rate among inpatients (27.3%) compared to outpatients (10.6%). Proteus was more significantly isolated from catheterized UTI patients (28.2%, 55/195) than from non-catheterized patients (14.9%, 48/321). Of the 103 Proteus isolates, 99 (96.1%) were identified as P. mirabilis. High resistance was observed against trimethoprim/sulfamethoxazole (SXT) (80.6%), amoxicillin-clavulanic (AMC) (57.3%), ceftazidime (55.3%), and imipenem (46.6%) antibiotics. Significantly higher resistance rates were observed among Proteus isolates from inpatients and catheterized patients. Of the 103 Proteus strains, 81 (78.6%) were MDR, with 70.9% of the isolates from catheterized patients. About 74.6% of the isolates from inpatients were MDR. Sul genes were detected in 77 isolates (74.7%). The frequency of ESBL-producing Proteus isolates was 37.9% which was significantly higher in catheterized patients with increasing dissemination of blaTEM genes and blaCTX-M genes. Int1 and Int2 genes were detected in 92.2% and 68.9% of isolates, respectively. ERIC-PCR revealed moderate similarity (65%) between ESBL-producing Proteus isolates from catheterized patients.ConclusionThe high frequency of MDR P. mirabilis strains isolated from UTIs in Egypt, particularly among catheterized patients, is a major concern, especially with disseminating class 1 and 2 integrons among isolates. The study also highlights the decreased susceptibility to sulphonamides, 3rd generation cephalosporins, and imipenem, commonly used to treat UTIs. Increased dissemination of ESBL-producing Proteus isolates among CAUTIs complicates their treatments. This important pathogen deserves more attention in the future for a better understanding of resistance mechanisms and the dissemination potential of resistant strains.

Variable In Vitro Efficacy of Delafloxacin on Multidrug-Resistant Pseudomonas aeruginosa and the Detection of Delafloxacin Resistance Determinants

Background: In this study, molecular mechanisms contributing to delafloxacin resistance in Pseudomonas aeruginosa strains were investigated. Delafloxacin is a recently approved fluoroquinolone currently introduced to clinical applications. Methods: A total of 52 P. aeruginosa strains were collected from clinical isolates. Antimicrobial susceptibility testing was performed via broth microdilution, and the minimum inhibitory concentration (MIC) values for ciprofloxacin, levofloxacin, delafloxacin, ceftazidime and imipenem were determined. Five delafloxacin-resistant P. aeruginosa strains were selected for whole-genome sequencing (WGS). Results: MIC50 values were determined, and the following results were obtained: ciprofloxacin 0.25 mg/L, levofloxacin 0.25 mg/L and delafloxacin 1 mg/L. All five selected strains showed both extended-spectrum beta-lactamase and carbapenemase production. WGS analysis of these strains determined the sequence types (STs), namely, ST235 (two strains), ST316 (two strains) and ST395. Several mutations in quinolone-resistance-determining regions (QRDRs) were detected in all five delafloxacin-resistant P. aeruginosa strains as follows: gyrA Thr83Ile and parC Ser87Leu mutations were present in all five strains, while parE Thr223Ala in ST235, Glu459Val in ST316 and Val200Met in ST395 were detected. MexAB-OprM and MexCD-OprJ efflux pumps were uniformly present in all delafloxacin-resistant P. aeruginosa strains. All strains of ST235 and ST316 carried blaNDM-1 in combination with other beta-lactamases. In our study, the in vitro efficacy of delafloxacin is inferior compared to previous fluoroquinolones based on MIC50 values; however, MIC values of delafloxacin ranged between 0.125 and 128 mg/L in our P. aeruginosa collection, and 21 out of 52 strains showed susceptibility to delafloxacin. Conclusions: Multiple QRDR mutations combined with several efflux pumps confer delafloxacin resistance in P. aeruginosa. Among the different detected multidrug-resistant P. aeruginosa strains in this study, we also report on an NDM-1 producing P. aeruginosa ST316 in Hungary.

Molecular Characterization of Antibiotic Resistance Genes in Hospital-Acquired Urinary Tract Infections

Introduction: Hospital-acquired urinary tract infections (HAUTIs) represent a major challenge in healthcare due to increasing multidrug resistance (MDR) among causative pathogens. Objective: This study aimed to molecularly characterize antibiotic resistance genes in bacterial isolates from HAUTI patients and assess their antimicrobial susceptibility profiles. Methodology: A total of 150 urine samples were collected from hospitalized patients diagnosed with HAUTIs. Bacterial isolates were identified using standard microbiological methods, and antibiotic susceptibility testing was performed following Clinical and Laboratory Standards Institute (CLSI) guidelines. Phenotypic screening for extended-spectrum beta-lactamase (ESBL) and carbapenemase production was conducted, followed by polymerase chain reaction (PCR) assays targeting key resistance genes including bla_CTX-M, bla_TEM, bla_SHV, bla_NDM, bla_OXA-48, and bla_KPC. Results: Out of 114 isolates recovered, Escherichia coli (40.4%) and Klebsiella pneumoniae (24.6%) were predominant. High resistance rates were observed against third-generation cephalosporins, fluoroquinolones, and carbapenems, with 68.4% of isolates classified as MDR. ESBL production was confirmed phenotypically in 57.0% of isolates, predominantly in E. coli and K. pneumoniae. Carbapenemase activity was detected in 25.4% of isolates, especially in K. pneumoniae and Acinetobacter baumannii. PCR analysis revealed bla_CTX-M as the most prevalent gene (66.7%), followed by bla_TEM (48.7%) and bla_NDM (26.9%). Conclusion: Co-occurrence of multiple resistance genes was common, highlighting the complexity of resistance mechanisms. The study underscores the critical need for continuous molecular surveillance and stringent antimicrobial stewardship to effectively manage HAUTIs and prevent the spread of resistant pathogens in healthcare settings.

Antimicrobial Resistance and Prevalence of β-lactamase Genes Among Multidrug-Resistant Acinetobacter baumannii Isolates from Infected Diabetic Foot Ulcers

Diabetic foot infections (DFIs) are a severe complication of diabetes and are increasing in prevalence globally. The microbiology of DFIs exhibits significant regional variation, with Acinetobacter baumannii frequently emerging as the predominant pathogen. This study aimed to investigate the microbiological profile of A. baumannii in DFIs of different Wagner grades. Pus and tissue specimens from 480 diabetic patients treated for DFIs between September 2016 and August 2019 were collected, and antimicrobial susceptibility testing was performed. Multiplex PCR was conducted to amplify extended spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) genes. A. baumannii had a prevalence of 14.58% in DFIs, with 100% resistance to cephalosporins. Among the 70 A. baumannii isolates, 19 (27.14%) were ESBL producers and 43 (61.43%) were MBL producers. blaTEM was the most prevalent gene (52.94%) in ESBL producers; blaNDM-1 was the most prevalent gene (52.94%) in MBL producers. Our findings highlight the need for regular antimicrobial susceptibility testing, molecular surveillance, and robust antimicrobial stewardship programmes to effectively manage A. baumannii DFIs and mitigate their resistance.

Prevalence and molecular characterization of multi-drug and extreme drug resistant Escherichia coli in companion animals in Bangladesh

The study aimed to investigate multi-drug resistant (MDR) Escherichia coli (E. coli) in companion animals in Bangladesh, with a focus on the resistance profiles of isolates from non-food-producing animals. In 2023, the studied samples were from cats, dogs, and environmental sources linked with companion animal hospitals in Dhaka city, Bangladesh. E. coli was isolated using standard techniques and its antimicrobial resistance (AMR) was assessed against 23 antibiotics following the CLSI protocols. Metallo-beta-lactamase genes (blaNDM-1 and blaNDM-5) and mobile genetic elements (class 1 integron) were detected by multiplex PCR. The overall prevalence of E. coli was 70%, 76% in cats, 65.71% in dogs, and 65.71% in the environmental samples. Cefuroxime exhibited the highest resistance at 25%, while imipenem and nitrofurantoin showed the highest sensitivity at 100%, followed by ceftazidime at 95%. MDR strains made up 38.10%, while 11.90% were extremely drug-resistant (XDR). Additionally, 29% of E. coli were extended-spectrum beta-lactamase (ESBL) producers. The prevalence and association among class 1 integron and the resistant genes including blaNDM-1 and blaNDM-5 were also notable. This highlights the complex AMR challenges in these settings, including the presence of class 1 integron—a key element involved in capturing and transferring antimicrobial resistance genes.

A survey on antibiotic resistance of Extended-Spectrum beta-lactamase-producing Escherichia coli isolated from urinary tract specimens at Hue University of Medicine and Pharmacy Hospital

Background: Urinary tract infections caused by Extended-Spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) strains are a major concern and a key driver of β-lactam antibiotic group’s resistance. Finding the frequency of ESBL-producing E. coli isolated from urine samples and analyzing their antibiotic resistance profiles were the objectives of this study. Materials and methods: A retrospective, cross-sectional study was conducted on urine samples at Hue University of Medicine and Pharmacy Hospital from January 2023 to April 2024. Bacterial culture, identification, and antibiotic susceptibility testing were performed according to standard microbiology laboratory procedures. Results: 104 ESBL-producing E. coli strains were isolated, accounting for 45.2% of patients with urinary tract infections caused by E. coli. This group was most common in patients over 60 years old, primarily from patients of the Urology outpatient clinic and the Department of General Internal Medicine - Endocrinology - Musculoskeletal and the prevalence was quite similar between males and females (46.9% and 44.6% respectively). The isolates showed high resistance to ampicillin, some cephalosporins, and quinolones, but still remained highly susceptible (>90%) to carbapenems and fosfomycin, and fully susceptible to nitrofurantoin. Conclusion: E. coli producing ESBL are a real burden in the treatment of urinary tract infections. Consequently, investigating the antibiotic resistance profiles of ESBL-producing E. coli in clinical settings is essential for informing physicians’ decisions on appropriate antimicrobial therapy.

Comprehensive surveillance of antimicrobial susceptibility across adult and pediatric populations in Catalonia: Insights from community, hospital, and long-term care facility settings.

Comprehensive surveillance of antimicrobial susceptibility across adult and pediatric populations in Catalonia: Insights from community, hospital, and long-term care facility settings.

Prevalence, antimicrobial resistance, and genetic profile of Escherichia coli in retail chicken parts in Zagazig City, Egypt.

Prevalence, antimicrobial resistance, and genetic profile of Escherichia coli in retail chicken parts in Zagazig City, Egypt.

Tossing the coin of extended-spectrum β-lactamase: prevalence of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolated from patients with sepsis.

Background. Klebsiella pneumoniae is part of the ESKAPE (Enterococcus faecium, Staphylococcus aureus, K. pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) group of multidrug-resistant (MDR) pathogens. K. pneumoniae is the leading cause of antimicrobial resistance-associated mortality and the second leading cause of nosocomial bloodstream infections (BSIs), globally and in sub-Saharan Africa. Therefore, it was aimed to determine the antibiotic resistance patterns of K. pneumoniae isolated from blood cultures of patients with features of sepsis at Mulago National Referral Hospital, Uganda. Methods. The cross-sectional study on patients with features of sepsis utilized K. pneumoniae (n=30) isolated from positive blood culture specimens. The antibiotic resistance profile was determined by the Clinical and Laboratory Standards Institute's Kirby-Bauer disc diffusion method, which was used to classify the isolates as susceptible, intermediate and resistant. K. pneumoniae isolates that were resistant to third-generation cephalosporins were subjected to extended-spectrum β-lactamase (ESBL) screening and confirmation using the double-disc synergy test using cefotaxime, ceftazidime, ceftriaxone, cefotaxime-clavulanic acid and ceftazidime-clavulanic acid. The results were analysed for frequencies. Results. K. pneumoniae isolates showed emerging resistance to imipenem at 13% (4 out of 30) followed by amikacin at 17% (5 out of 30). There was intermediate resistance to gentamycin at 60% (18 out of 30). However, K. pneumoniae showed the highest resistance to piperacillin at 100% (30 out of 30) followed by sulphamethoxazole-trimethoprim and cefepime, both showing a percentage of 97% (29 out of 30). Up to 16 out of 30 (53.3%) of K. pneumoniae were positive for ESBL production, whilst 14 out of 30 (46.7%) were negative. Conclusion. There was a high prevalence of antibiotic-resistant ESBL-producing K. pneumoniae isolates from BSI of patients with features of sepsis in Uganda's Mulago National Referral Hospital.

The first report of antibiotic resistance and virulence factor profiles in multidrug-resistant clinical isolates of Klebsiella pneumoniae from Pontianak, Indonesia.

Klebsiella pneumoniae is known as one of the most common causes of hospitalacquired infections. Its prevalence poses substantial challenges to both hospital and public health systems, particularly due to the rise of multidrug-resistant strains. Understanding the epidemiology and resistance properties of K. pneumoniae can inform antimicrobial stewardship and infection control programs. A cross-sectional study was employed from November 2021 to November 2023. A total of 24 isolates underwent antimicrobial susceptibility testing using the disk diffusion method, an extended-spectrum beta-lactamase (ESBL) production test, and molecular gene detection. The study found that 95.8% of clinical isolates were classified as multidrug-resistant. All isolates were resistant to ampicillin (100%). A high percentage of isolates were resistant to cefazolin (91.7%), ceftriaxone (87.5%), cefotaxime (87.5%), cefepime (87.5%), ciprofloxacin (83.3%), and sulfamethoxazole-trimethoprim (83.3%). Of the 24 isolates, 87.5% harbored ESBL genes, while the frequencies for GES, NDM, SIM, and OXA-48 were 16.7%, 20.8%, 8.3%, and 41.7%, respectively. Notably, the OXA-23 and OXA-51 genes, which are typically associated with Acinetobacter baumannii, were detected in 16.7% and 20.8% of isolates, respectively. Moreover, the prevalence of virulence genes rmpA, acrAB, and tolC was 0%, 95.8%, and 87.5%, respectively. This study demonstrated a high level of antibiotic resistance and a significant presence of virulence genes among K. pneumoniae isolates. Consequently, these findings represent a critical public health issue that requires heightened awareness among all stakeholders, including health workers.

Genetic characterization of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae collected from healthy turkeys.

The spread of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-En) from turkeys via food chain and environmental contamination is a human health concern. Seventy fecal samples were collected from healthy turkeys and streaked on Tryptone Bile X-Glucoronide (TBX) supplemented with 2 mg/L of cefotaxime and on TBX supplemented with 1 mg/L of imipenem. ESBL production and susceptibility to antibiotics were studied according to CLSI guidelines. Genes encoding for ESBLs (SHV, CTX-M, TEM), carbapenemases (IMI, KPC, OXA48, NDM), tetracyclines (tetA, tetB, tetC), colistin (mcr-1 to mcr-5), sulphonamides (sul1, sul2), quinolones (qnr A/B/S, aac(6')-Ib-cr, qepA) resistance, and class 1 and 2 integrons were determined by PCR. ESBL-En [n = 45 (64.3%): 41 E. coli and 4 K. pneumoniae] isolates were collected. In E. coli, blaCTX-M-1, blaCTX-M-14, blaCTX-M-15, blaCTX-M-27, and blaCTX-M-55 genes were identified in 23, 2, 5, 16, and one isolate, respectively. The blaCTX-M-15 gene was detected in two K. pneumoniae isolates, while each of blaCTX-M-1 and blaCTX-M-27 were detected in one isolate. Resistances to tetracyclines, sulfonamides, fluoroquinolones, and colistin were encoded by tetA (n = 21)/tetB (n = 1), sul1 (n = 8)/sul2 (n = 13), aac(6')-Ib-cr (n = 6), and mcr-1 (n = 2)/mcr-2 (n = 1) genes, respectively. Integrons of class 1 and class 2 were detected in 15 and six isolates, respectively. Five E. coli isolates belonged to the pandemic ST131 clone. Our findings highlight the high occurrence of MDR/ESBL-En and demonstrate the possible transfer of these strains to humans via the food chain or direct contact.

Presence of extended-spectrum β-lactamase in Escherichia coli strains isolated from beef, pork, and chicken meats sold in Recife, Brazil

This study aimed to identify extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in chicken, beef, and pork meats sold in Recife, Pernambuco, Brazil. A total of 120 meat samples (40 of each type) were collected from supermarkets, butcher shops, and open-air markets across the city’s eight health districts, using convenience sampling. The samples were processed in a microbiology laboratory, and E. coli was identified through selective isolation on eosin-methylene blue agar and biochemical tests. Phenotypic resistance was assessed using disk diffusion tests on Müller–Hinton agar with cefotaxime, ceftazidime, and ceftriaxone disks, followed by the double-disk synergy test to confirm ESBL production. Genotypic analysis was conducted by polymerase chain reaction to detect the blaTEM and blaSHV genes. Of the 40 E. coli isolates obtained, 34 (85%) exhibited phenotypic resistance, while 21 (52.5%) and 23 (57.5%) tested positive for the blaSHV and blaTEM genes, respectively. A higher prevalence of blaSHV was observed in pork samples (73.3%, 11/15), whereas blaTEM was more prevalent in beef (70%, 7/10). The presence of resistant bacteria in commercial meats highlights contamination risks in the production chain and underscores the need for surveillance and public awareness to protect human health.

Phenotypic and Molecular Characterization of Uropathogenic Extended-spectrum Beta-Lactamases Producing Isolates from Community in Different Regions of Bangladesh

Background: Prevalence of Extended-spectrum ß-lactamases (ESBL) producing uropathogenic strains have been found to be increased rapidly across the world including Bangladesh. Objective: This study was aimed to presents phenotypic and molecular characterization of ESBL producing Enterobacteriaceae and their antibiogram profile isolated from UTI patients of six different districts of Bangladesh. Methodology: This cross-sectional study was conducted in Microbiology Laboratory of BIRDEM general hospital, Dhaka, Bangladesh with 187 culture positive cases collected from six laboratories of Feni, Faridpur, Kishoreganj, Sirajganj, Shatkhira and Brahmanbaria during the period from September, 2018 to August, 2019 for one year. Different members of Enterobacteriaceae were isolated and susceptibilities of these isolates to 17 different antimicrobial agents were determined. Ceftazidime (CAZ), cefotaxime (CTX), ceftriaxone (CRO) and amoxiclave (AMC) were used for confirmation of ESBL producing isolates in Double Disc Synergy Test (DDST). Frequency of blaCTX-M, blaTEM and blaSHV among these isolates were further detected in this study. Results: Out of 187 culture positive cases, 171 samples were Enterobacteriaceae including Escherichia coli, Klebsiella species, Enterobacter species and Proteus mirabilis. Among them, 85 isolates were screened to be ESBLs producing Enterobacteriaceae and 52 isolates were confirmed as ESBL isolates in DDST. MIC of ceftazidime and MIC reduction of ceftazidime-clavulanic acid for confirmed ESBL producers was found ranged from 0.125ug/ml to 64ug/ml and 0.0156ug/ml to 32ug/ml respectively. Among 52 ESBL isolates, the blaCTX-M (86.3%) gene was predominant followed by blaSHV (22.7%) and blaTEM (18.2%) in ESBLs producing E. coli. All three bla genes were harboured in 2.3% and blaCTX-M+SHV were in 18.2% E. coli. Conclusion: Alarmingly increasing spread of single gene type blaCTX-M and blaSHV harboring multidrug-resistant ESBL producing Enterobacteriaceae in six district regions of Bangladesh emphasize ESBL detection routinely in all microbiology laboratories by DDST as rapid and cost-effective method and development of rational use of antibiotic strategies in UTI to control spread of ESBL production in community of Bangladesh. Bangladesh Journal of Medical Microbiology, January 2025;19 (1):60-69

Antibiotic Resistance Profiles, Phenotypic Analysis and Molecular Genotyping of Extended-Spectrum Beta-Lactamases-Producing Enterobacteriaceae Isolated from Red Meat Collected from Dhaka City of Bangladesh

Background: It is generally acknowledged that one of the most significant issues facing modern human are those with broad activity spectra that render all or most medicines in a particular treatment category ineffective. Objective: The goal of this study is to evaluate the microbiological quality of raw meat, specifically focusing on the frequency of Extended-Spectrum Beta-Lactamases (ESBL) production among Enterobacteriaceae, and to assess the antibiotic susceptibility of these isolates in vitro as well as to conduct a molecular characterization of ESBL to better understand the genetic mechanisms behind their production. Methodology: This comparative cross-sectional study was conducted in neighborhood marketplaces of Dhaka, including Bashundhara, Azimpur, and Dhanmondi Bazar, from November 2022 to August 2023. A total of 40 beef and mutton samples were collected directly from slaughterhouses and transported to the NSU laboratory in sterile Ziploc bags without freezing. For pure culture, Mac Conkey agar plates were utilized after sample collection. Muller-Hinton agar media (MHA) was used for antibiotic susceptibility testing after completion of organism detection test on Eosin-methylene blue (EMB) agar media. DNA was extracted using the hot boiling method. The purity of the DNA was assessed to ensure its quality. Gel electrophoresis was then performed to verify DNA integrity. Finally, PCR was conducted for genetic confirmation of specific sequences. Results: Among 40 samples, 95% of the bacteria discovered belonged to the Enterobacteriaceae family. Five (or 25%) of the beef samples showed resistance against the combination of Ceftazidime (CAZ) and Amoxicillin-Clavulanic acid (AMC). About the mutton, 20 (100%) cases were found resistant to CAZ+AMC (100%), and 12 instances were resistant to CTX (Cefotaxime) +AMC (60%). Several strains (17.5%) in our investigations demonstrated phenotypic positive for producing the ESBL enzyme. Of 40 dietary samples, 35% of the strains that create ESBL are identified in beef and mutton, respectively, with 30% and 5% 0f theses strains producing ESBL. In this study, the focus was on two specific gene types, namely the VIM and DHA genes. The genotype known as blaDHA (Variation of the dihydrofolate reductase gene) was identified as the causative factor in 2.5% of all cases, while the genotype referred to as blaVIM (Verona -Integron encoded- Metallo-beta-lactamases) was responsible for 2.5% of the cases of total 40 strains. Conclusion: Antibiotic resistance is an important health issue due to the potential pathogenicity. Bangladesh Journal of Medical Microbiology, January 2025;19 (1):26-34

Study on extended-spectrum beta-lactamases genes and drug resistance in patients with urinary tract infection of enterohemorrhagic Escherichia coli after bladder cancer surgery.

To explore of the detection of enterohemorrhagic Escherichia coli with extended-spectrum beta-lactamase (ESBLs) in patients with urinary tract infections (UTIs) after bladder cancer surgery, and analysis of their genotypic distribution and drug resistance. From February 2022 to February 2024, patients who underwent bladder cancer surgery at our hospital were collected. Among them, those who developed UTIs with enterohemorrhagic E coli postoperatively had their urine specimens isolated and cultured, resulting in 87 strains of enterohemorrhagic E coli. Cultures were conducted on the obtained enterohemorrhagic E coli samples, ESBLs production was screened, and drug sensitivity tests were performed to investigate the resistance rate and antibacterial effects. Additionally, genotypic testing was conducted. This study successfully isolated 87 strains of E coli, among which 49 strains (56.32%) were found to produce ESBLs after screening. The resistance rates of these ESBL-producing E coli to cefotaxime and ampicillin were relatively high (93.88% and 97.96%, respectively), while the resistance rate to imipenem was the lowest (2.04%). Genotypic testing revealed that among the 49 strains of ESBL-producing E coli, the detection rate of blaCTX-M-14 was the highest at 53.06%, followed by bla-TEM at 30.61%. The detection rates of bla-SHV (4.08%), bla-OXA (2.04%), blaCTX-M-3 (2.04%), blaCTX-M-15 (2.04%), as well as combinations of several genotypes (blaCTX-M-3 + bla-TEM, blaCTX-M-14 + bla-TEM, blaCTX-M-15 + bla-TEM, all with a detection rate of 2.04%), were relatively low. Strains carrying the bla-TEM genotype exhibited 100% resistance rates to ampicillin and tetracycline. Strains carrying the blaCTX-M-14 genotype showed a 100% resistance rate to ampicillin and a 96.15% resistance rate to cefotaxime. Bladder cancer patients with postoperative complications of E coli urinary tract infection have a detection rate of 56.32% for ESBL-producing E coli. The detected ESBL-producing strains show a high resistance rate to ampicillin and cefotaxime, with the lowest resistance rate observed against imipenem. Genotypic analysis reveals that blaCTX-M-14 and bla-TEM are the main ESBL genes, with blaCTX-M-14 having the highest detection rate.

Mapping Antimicrobial Resistance in Escherichia coli and Klebsiella pneumoniae from Complicated Urinary Tract Infections in Oman: Phenotypic and Genotypic Insights.

Background: Mapping the local etiology and susceptibility of common pathogens causing complicated urinary tract infection (cUTI) is important for promoting evidence-based antimicrobial prescribing. Evaluating the prevalence of extended-spectrum beta-lactamase (ESBL), AmpC beta-lactamase (AmpC), and carbapenemase-producing Enterobacterales (CPEs) is equally important as it informs treatment guidelines and empiric management. Whole genome sequencing (WGS) enhances antimicrobial resistance (AMR) surveillance by complementing phenotypic antimicrobial susceptibility testing, offering deeper insights into resistance mechanisms, transmissions, and evolutions. Integrating it into routine AMR monitoring can significantly improve global efforts to combat antimicrobial resistance. Methods: Antimicrobial susceptibility profiles of isolates from cUTI were collected from patients presenting with Sultan Qaboos University Hospital, Muscat and Suhar Hospital, Suhar, Oman. Automated systems as well as manual methods were used for detection of ESBL, AmpC, and CPE. ESBLs, AmpC β-lactamases, and CPEs were further detected by manual methods: double-disk synergy test for ESBL; disk approximation assay and D69C AmpC detection set for AmpC, and mCIM and KPC/IMP/NDM/VIM/OXA-48 Combo test kit for CPE. WGS was carried out in 11 FOX-resistant E. coli and (22 carbapenem-resistant K. pneumoniae) isolates with varying susceptibilities to identify circulating clades, AMR genes, and plasmids. Bioinformatic analysis was performed using online tools. Results: The susceptibility patterns of E. coli from cUTI were as follows: nitrofurantoin (96%), fosfomycin (100%), fluoroquinolones (44%), aminoglycosides (93%), piperacillin-tazobactam (95%), and carbapenems (98%). In comparison, susceptibility rates of K. pneumoniae were far lower: nitrofurantoin (38%), fosfomycin (89%), aminoglycosides (82%), piperacillin-tazobactam (72%), and carbapenems (83%). K. pneumoniae, however, was more susceptible to fluoroquinolones at 47% in comparison to E. coli. The prevalence of ESBL among E. coli and K. pneumoniae was 37.2% and CRE was 6.2% while the estimated prevalence of AmpC was 5.4%. It was observed that E. coli was the predominant ESBL and AmpC producer, while K. pneumoniae was the major carbapenem-resistant Enterobacterales (CREs) producer. No predominant multi-locus sequence typing (MLST) lineage was observed in AmpC-producing E. coli with nine E. coli MLST lineages being identified from eleven isolates: ST-10, ST-69, ST-77, ST-131, ST-156, ST-167, ST-361, ST-1125, and ST-2520. On the other hand, a less diverse MLST spectrum (ST-2096, ST-231, ST-147, ST-1770, and ST-111) was observed in the CRE K. pneumoniae. Among the five MLST lineages, ST-2096 (twelve isolates) and ST-147 (seven isolates) predominated. WGS revealed that DHA-1 was the predominant plasmid-mediated AmpC gene in E. coli, while OXA-232 and NDM-5 were the most common carbapenemase genes in K. pneumoniae. All E. coli DHA-1-positive isolates co-harbored the quinolone resistance gene qnrB4 and the sulfonamide resistance gene sul1 while no aminoglycoside resistance genes were detected. The majority of CPE CRE K. pneumoniae carried other β-lactamase genes, such as blaCTX-M-15, blaSHV, and blaTEM; all co-harbored the quinolone resistance gene OqxAB; and 77% carried the aminoglycoside resistance gene armA. Conclusions: Our results suggest that fosfomycin is an excellent empiric choice for treating complicated cystitis caused by both E. coli and K. pneumoniae, while nitrofurantoin is an appropriate choice for E. coli cystitis but not for K. pneumoniae. Aminoglycosides and piperacillin-tazobactam are excellent intravenous alternatives that spare carbapenems. DHA-1 was the predominant AmpC in E. coli, while OXA-232 and NDM-5 were the predominant carbapenemases in K. pneumoniae. In AmpC-producing E. coli, no MLST predominated, suggesting a significant flux in E. coli with lack of stable clades in this region. In contrast, ST-2096 and ST-147 predominated in CRE Klebsiella pneumoniae, suggesting a stable circulation of these in Oman. WGS profiling provides a deeper understanding of the genetic basis of resistance and enhances surveillance and offers comprehensive insights into pathogen evolution and transmission patterns.