Extended-spectrum Β-lactamase Research Articles

Extended-Spectrum β-Lactamase and carbapenemase-producing Escherichia coli O157:H7 among diarrheic patients in Shashemene, Ethiopia.

The worldwide increase in multidrug resistance is a major threat to public health. One particular concern is the presence of Escherichia coli strains that carry Extended-Spectrum β-Lactamase (ESBL) and Carbapenemase enzymes, which can make multiple antibiotics ineffective. This complicates treatment strategies and raises the risk of illness and death. The aim of this study was to isolate E. coli O157:H7, assess its susceptibility against antimicrobial agents, and determine the presence of ESBL and Carbapenemase production in stool samples collected from diarrheic patients in Shashemene, west Arsi, Ethiopia from July to November 2022. The samples were cultured McConkey Agar and E. coli were isolated and identified by standard biochemical tests using API 20E. E. coli O157:H7 was further identified using sorbitol McConkey Agar and antisera for O157 antigen test. The antimicrobial susceptibility test was performed using the Kirby-Bauer disc diffusion method using different antibiotics. Each identified isolate was screened and tested for phenotypical ESBL and Carbapenemase production using combined disc method and modified carbapenem inactivation method, respectively. Bivariant and multivariant analyses were employed using a logistic regression model for further analysis and were interpreted based on the odds ratio and level of statistical significance at a p-value <0.05 with 95% confidence interval. E. coli O157:H7 strain was found from 9% (38/423) study participants. The majority of the participants [61.9% (262/423)] were males; and 19.1% (81/ 423) of the participants were under five children. Living in urban areas, having domestic animals, and ≥5 family size in the household were identified as statistically significant factors associated with E. coli O157:H7. Twenty-seven (71.1%) and 12 (31.6%) of the 38 E. coli O157:H7 isolates were phenotypically confirmed to be ESBL and carbapenemase producers, respectively. All isolates were resistant against Ampicillin, but sensitive to ciprofloxacin. High resistance to Ampicillin and Amoxicillin/Clavulanic acid was observed among the ESBL and carbapenemase producing isolates also. The extent of detection of multidrug resistant E. coli O157:H7 isolates against three or more classes of antimicrobial agents tested was alarmingly very high (84%). The E. coli O157:H7 isolates in this study showed a significant resistance to certain antimicrobials that were tested. The level of ESBL and Carbapenemase production among these isolates was found to be quite high. We observed a high resistance to Ampicillin and Amoxicillin/Clavulanic acid among the ESBL and carbapenemase producing isolates. Ciprofloxacin was found to be the most effective drug against both the ESBL producers and nonproducers.

Whole genome sequencing and genotyping Klebsiella pneumoniae multi-drug resistant hospital isolates from Western Kenya.

Klebsiella pneumoniae are a frequent cause of nosocomial infections worldwide. Sequence type 147 (ST147) has been reported as a major circulating high-risk lineage in many countries, and appears to be a formidable platform for the dissemination of antimicrobial resistance (AMR) determinants. However, the distribution of this pathogen in Western African hospitals has been scarcely studied. The main objective of this work was to perform whole genome sequencing of K. pneumoniae isolates from a referral hospital in Kakamega (Kenya) for genotyping and identification of AMR and virulence determinants. In total, 15 K. pneumoniae isolates showing a broad spectrum antimicrobial resistance were selected for whole genome sequencing by Illumina HiSeq 2500 platform. ST147 was the dominant lineage among the highly-resistant K. pneumoniae isolates that we sequenced. ST147 was associated with both community- and the hospital-acquired infections, and with different infection sites, whereas other STs were predominantly uropathogens. Multiple antibiotic resistance and virulence determinants were detected in the genomes including extended-spectrum β-lactamases (ESBL) and carbapenemases. Many of these genes were plasmid-borne. Our data suggest that the evolutionary success of ST147 may be linked with the acquisition of broad host-range plasmids, and their propensity to accrue AMR and virulence determinants. Although ST147 is a dominant lineage in many countries worldwide, it has not been previously reported as prevalent in Africa. Our data suggest an influx of new nosocomial pathogens with new virulence genes into African hospitals from other continents.

Trends in antimicrobial susceptibility patterns in Salmonella from human and nonhuman sources in Sao Paulo State, Brazil, 2016-2023.

Antimicrobial resistance constitutes a significant global challenge to public health and development, in which non-typhoidal Salmonella emerges as a critical concern. This study investigates the prevalence and antimicrobial resistance profiles of Salmonella isolates from both human and nonhuman sources. A total of 2,511 Salmonella isolates that had been collected from 2016 to 2023 were analyzed, of which 1,724 underwent antimicrobial susceptibility testing. The main focus lied on the 10 most prevalent serotypes, totaling 957 isolates. Serotyping showed the diverse distribution of serotypes, with Heidelberg, Typhimurium, Enteritidis, and the monophasic Salmonella Typhimurium occurring most often. Antimicrobial resistance was common since 512 strains resisted at least one drug and 319 several drugs. Notably, the Heidelberg and Mbandaka serotypes, predominantly occurring in nonhuman samples, showed multidrug resistance. Salmonella Typhi remained susceptible to antimicrobials. Resistance to nalidixic acid, tetracycline, sulfonamides, and ampicillin was prevalent, whereas all isolates remained susceptible to imipenem. A reduction in susceptibility rates for aminoglycosides was observed over the study period. Extended-spectrum β-lactamase production occurred in 4.4% of the isolates, of which Heidelberg configured the most prevalent extended-spectrum β-lactamase-positive serotype. These findings underscore the importance of surveillance and effective monitoring to control this pathogen, highlighting the necessity of prioritizing public health efforts.

Antibiotic susceptibility and virulence factors of bacterial species among cancer patients

Antibiotic resistance is one of the most significant challenges of the 20-s century, and the misuse of antibiotics is a driver of antimicrobial resistance. This study aimed to assess the prevalence of multidrug resistance, and detection of its produce virulence factors, including extended-spectrum β-lactamases (ESβLs), biofilm, and siderophores produced by bacterial species isolated from cancer patients. One hundred and seventy-five Gram-negative bacterial isolates were isolated from different samples collected from cancer patients admitted to the National Cancer Institute (NCI), Cairo, Egypt, and processed by standard microbiological methods. One hundred and forty-three bacterial isolates were recovered from adult patients, and 32 were recovered from children. Escherichia coli showed the highest frequency (36%), followed by Klebsiella pneumonia (30.85%), Acinetobacter baummannii (14.28%), and Pseudomonas sp. (9.14%). Antibiotic profiles revealed that bacterial isolates are highly resistant to the most commonly available antibiotics. Amikacin and gentamicin were the most effective antibiotics against isolated Gram-negative bacteria. Moreover, the vast majority of bacterial stains produce virulence factors, including EsβLs, biofilm, and siderophores. E. coli isolates produced ESβLs with rates of 25.28%, Klebsiella pneumonia (11.0%), and Pseudomonas sp. (25.0%). Among these collected bacterial isolates, 132 (75.4%) have the ability to form a biofilm to different degrees. Also, the majority of the bacteria isolates generated siderophores, with 133 (75.94%). This study revealed that a significant distribution of multidrug-resistant pathogenic bacteria may increase the burden on healthcare to prevent infections in cancer patients.

Relationship between Biofilm Formation and Production of Extended-Spectrum β-lactamases and Metallo-β-lactamases among Gram-negative Bacilli

Relationship between Biofilm Formation and Production of Extended-Spectrum β-lactamases and Metallo-β-lactamases among Gram-negative Bacilli

Phylogenetic Characterization of Resistant Salmonella Strains in Typhoid Fever Patients in Nigeria.

Salmonella species are Enterobacteriaceae associated with typhoid fever. In this study, the distribution of broad-spectrum β-lactamase regulatory genes and genetic relatedness of isolates was determined. Stool samples (400) were collected from patients with fever in Dalhatu Araf Specialist Hospital (DASH), Lafia, Nigeria, between March 2020 and April 2021. Salmonella species were isolated and extended-spectrum β-lactamase distribution was determined among resistant isolates using polymerase chain reaction (PCR). Genetic relatedness of Salmonella species resistant to the 10 first-line antibiotics administered was determined among S typhi isolated. Of the 60 isolates that were confirmed to belong to the genus Salmonella, 12 (20.0%) isolates with bla SHV genes were the most prevalent, blaOXA-1 and blaCTX-M-9 were present in 5 isolates each, while blaCTX-M-4 and blaTEM genes with a prevalence of 1.7% each were the least obtained in the isolates. Two isolates had a multidrug-resistant index (MDRI) of 1, and 2 others were positive with the S typhi staG gene. Sequencing to determine their diversity showed that isolates ST36 and ST138, respectively, had MDRI = 1 and are clustered in a group with a similarity coefficient of 0.00634. The 2 isolates had the highest genetic similarity, which indicates that the genetic diversity between the isolates is low, while Salmonella strain ST313L2 had a high level of genetic distance from the other isolates. The most resistant isolates are closely related which calls for concern.

Predicting Antibiotic Tolerance in hvKP and cKP Respiratory Infections Through Biofilm Formation Analysis and Its Resistance Implications.

Respiratory infections are a major global health concern, with Klebsiella pneumoniae standing out due to its evolving antibiotic resistance. This study compares the resistance profiles of hypervirulent Klebsiella pneumoniae (hvKP) and classical Klebsiella pneumoniae (cKP), aiming to shed light on their clinical implications. We analyzed 86 cases, comprising 42 hvKP and 44 cKP strains, using comprehensive antimicrobial susceptibility testing and clinical data evaluation to assess antibiotic tolerance and resistance mechanisms. Our findings reveal distinct resistance patterns between hvKP and cKP, highlighting the role of chromosomal mutations and plasmid-mediated gene transfer in conferring antibiotic resistance. Notably, hvKP strains exhibited unique resistance trends, including the production of extended-spectrum β-lactamases (ESBLs) and carbapenemases, differing from those of cKP. This research underscores the importance of continuous surveillance and the development of targeted therapies against antibiotic-resistant Klebsiella pneumoniae. It emphasizes the critical need for judicious antibiotic use and novel therapeutic approaches to combat respiratory infections caused by these increasingly resistant pathogens.

Extended spectrum cephalosporin (ESC) resistant Escherichia coli: Trends and seasonality in the Netherlands from 2014 to 2022

BackgroundAntimicrobial resistance (AMR) in livestock and the environment likely contribute to the prevalence of AMR in humans with potential detrimental effects on human health. As such, annual mandatory monitoring of AMR in livestock occurs within the European Union (EU), according to harmonised methods. Extended-spectrum cephalosporins-resistant (ESC-resistant) Escherichia coli (E. coli), including extended-spectrum β-lactamases (ESBL), AmpC β-lactamases (AmpC) and carbapenemase producing E. coli, are considered of particular importance and are therefore included in the monitoring program. MethodsUsing results from the annual monitoring of ESC-resistant E. coli from 2014–2022, trends in prevalence per animal sector were determined over the complete time period, as well as potential seasonal effects. ResultsDuring these nine years, significant changes were observed in the prevalence of ESC-resistant E. coli, in broilers, dairy cattle and veal calves, while no changes in prevalence were seen in slaughter pigs. Furthermore, the prevalence of ESC-resistant E. coli is positively correlated with warmer seasons (summer and autumn) for both dairy cattle and veal calves, while no associations were found for broilers and slaughter pigs. While temperature itself may play a role in the prevalence of ESC-resistant E. coli, other factors affecting the selective landscape, such as antibiotic usage, will also play a role. ConclusionA combined analysis of antimicrobial usage and prevalence of ESC-resistant E. coli through the year, both in livestock and human samples, would be an interesting follow-up of this study.

Prevalence and Risk Factors of β-Lactamase Genes of Extended-Spectrum β-Lactamases-Producing Escherichia coli From Dairy Farm Environments of Haryana, India.

Presence of extended-spectrum β-lactamases (ESBL)-producing Enterobacteriaceae in the dairy farm environment and food chain could be a possible interface for the exchange of antimicrobial resistance genes between humans and animals. A total of 600 samples comprised of raw bovine milk, faeces, feed, environmental swabs and water samples from 20 different bovine dairy farms in and around Hisar city, Haryana, India were analysed for presence of ESBL encoding genes. Out of 240 isolates of Escherichia coli obtained, 74 isolates were found to be ESBL producers. Maximum number of ESBL isolates were found from faeces (40.5%) followed by raw milk (37.8%) and environmental swabs (17.5%). Most of the ESBL E. coli isolates were sensitive to chloramphenicol (82.4%) and gentamicin (77.0%) antibiotics. The bla CTX-M gene was found to be most prevalent (52.0%) followed by bla TEM (9.45%) while bla SHV gene alone was not detected in any sample by simplex PCR. However, the co-expression of blaCTX-M + blaTEM (21.6%) and blaCTX-M + blaSHV (4.05%) genes were also observed. The housing system, milking method and the hygienic mangement practices followed at farm level are found to be significant risk factors of ESBL-producing E. coli in dairy farms of Haryana.

Estimation of latamoxef (moxalactam) dosage regimens against β-lactamase-producing Enterobacterales in dogs: a pharmacokinetic and pharmacodynamic analysis using Monte Carlo simulation.

One of the most significant research areas in veterinary medicine is the search for carbapenem substitutes for the treatment of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E). This study applied a pharmacokinetic/pharmacodynamic (PK/PD) strategy in validating optimal latamoxef (LMX) therapeutic regimens against canine ESBL-E infections. Five dogs were administered a bolus dose of 40 mg/kg LMX intravenously to measure serum drug concentrations and determine PK indices using the noncompartmental model. The highest minimum inhibitory concentration (MIC) with a probability of target attainment ≥90% was used to compute the PK/PD cutoff values for bacteriostatic (time for which the unbound drug concentration was above the MIC [fTAM] ≥ 40%) and bactericidal (fTAM ≥ 70%) effects when administered at 20, 30, 50, and 60 mg/kg, in addition to 40 mg/kg. The cumulative fraction of response (CFR) was determined using the MIC distribution of wild-type ESBL-E in companion animals. The PK/PD cutoff values can be increased by reducing the dosing interval rather than increasing the dose per time. Based on the calculated CFRs for ESBL-producing Escherichia coli and Klebsiella pneumoniae, all LMX regimens in this study and those administered at 30-60 mg/kg every 8 and 6 hr were found to be optimal (CFR ≥ 90%) for exerting bacteriostatic and bactericidal effects, respectively. However, the regimens of 50 and 60 mg/kg every 6 hr may merely exert bacteriostatic effects on ESBL-producing Enterobacter cloacae. Further clinical trials are required to confirm the clinical efficacy of LMX.

Multi-drug resistant (MDR) Gram-negative pathogenic bacteria isolated from poultry in the Noakhali region of Bangladesh.

Rapidly increasing antibiotic-resistant bacterial strains in Bangladesh's food and farm animals stem from the excessive and inappropriate use of antibiotics. To assess the prevalence of multi-drug resistant (MDR) Gram-negative bacteria in poultry chicks, we sought to isolate and identify strains carrying antimicrobial resistance genes. Isolation and identification involved biochemical tests, 16S rRNA sequencing, and PCR screening of species-specific genes. MDR patterns were evaluated using CLSI guidelines with seventeen antibiotics across twelve classes. Targeted gene sequences were amplified for the detection of Extended-spectrum β-Lactamase (ESBL), carbapenem, tetracycline, sulfonamide, and colistin resistance genes. Common isolates, such as Escherichia coli, Klebsiella pneumoniae, Proteus penneri, and Enterobacter hormaechei, exhibited average Multiple Antimicrobial Resistance (MAR) indices of 0.66, 0.76, 0.8, 0.84, and 0.81, 0.76, 0.84, 0.41 for broiler and layer chicken, respectively. Providencia stuartii and Salmonella enterica, exclusive to broiler samples, had MAR indices of 0.82 and 0.84, respectively. Additional isolates Morganella morganii, Aeromonas spp., and Wohlfahrtiimonas chitiniclastica were found in layers (Average MAR indices: 0.73, 0.71, and 0.91). Notably, M. morganii, E. hormaechei and W. chitiniclastica were identified for the first time in Bangladeshi poultry chicken, although their evolution is yet to be understood. In this study, Pan-drug resistance was observed in one P. stuartii (broiler) and one Aeromonas spp. (layer) with a MAR index 1, while all isolates exhibited MAR indices >0.2, indicating MDR. Antimicrobial resistance (AMR) gene screening identified blaTEM, blaSHV, tetA, and sul1 in a majority of the MDR strains. Interestingly, E. coli (lactose positive and negative) and E. hormaechei were exclusively found to possess the tetB gene. In addition, E. coli (lactose negative), Klebsiella pneumoniae, Enterobacter hormaechei, M. morganii, and P. stuartii were observed to carry the colistin-resistant mcr-1 gene, whereas sul2 was detected in E. coli (lactose positive and negative), E. hormaechei, P. stuartii, and P. penneri. These findings emphasize the health risk of our consumers of both broiler and layer chickens as they have turned into a potent reservoir of various AMR gene carrying MDR and Pan-drug resistant bacteria.

Effectiveness of oral antibiotics in managing extended-spectrum B-lactamase urinary tract infections: A retrospective analysis.

Urinary tract infections caused by extended-spectrum beta-lactamase organisms pose a significant concern worldwide. Given the escalating prevalence of drug resistance and the limited data on the effectiveness of oral antibiotics in treating these infections, this study aimed to assess the clinical outcomes in adult patients with extended-spectrum beta-lactamase urinary tract infections treated with oral antibiotics. A retrospective observational cohort study was conducted at King Abdulaziz Medical City, Saudi Arabia, from January 2018 to December 2021. It included patients ⩾18 years with complicated or uncomplicated urinary tract infections from extended-spectrum beta-lactamase Enterobacterales and treated with oral antibiotics as step-down or mainstay therapy. All-cause clinical failure within 30 days post-discharge was evaluated as the efficacy outcome. Statistical analyses were performed using SPSS software. Out of 643 screened patients, 152 patients met the inclusion criteria. The patients were divided into oral step-down therapy (51.3%) and oral-only (48.7%) groups. The majority (69.1%) were females, with a mean age of 62 years. Complicated urinary tract infections were diagnosed in (75.5%) of cases, and the predominant pathogen was E. coli (79.6%). Clinical failure was observed in 23.1% in the oral step-down group and 13.5% in the oral-only group, with no significant difference (p = 0.128). Total antibiotics duration was significantly lower in the oral-only group (8 days vs. 12.2 days; p < 0.001). Binary logistic regression identified elder age, diabetes mellitus history, and prior extended-spectrum beta-lactamase infection as predictors of clinical failure. This study suggests that both step-down or primary oral antibiotic treatment yielded similar clinical outcomes in managing patients with extended-spectrum beta-lactamase urinary tract infections. Further prospective studies are required to validate these findings.

Prevalence of Extended-spectrum beta-lactamases- producing Escherichia coli and Klebsiella pneumonia from patients attending Tripoli University Hospital, Tripoli, Libya

Prevalence of extended-spectrum β-lactamases (ESBLs)- producing E. coli and K. pneumoniae has been increased globally. The study aimed to detect the prevalence of ESBL-producing E. coli and K. pneumoniae isolated from clinical specimens in Tripoli university hospital (TUH) and to evaluate their antimicrobial resistance profile. We retrospectively reviewed the recorded cultures results in the microbiology laboratory, TUH during the first half of the year 2021. 77% of E. coli and 72.5% K. pneumonia were multidrug resistant. ESBL phenotype detected in 20% of K. pneumonia and 17.5% E. coli. ESBLs were isolated more frequently from the surgical ward (32.4%). ESBLs show high resistance to beta-lactam and other antibiotics including TMP/SMZ, and aminoglycosides. Our study showed a considerably high prevalence of ESBLs positive strains of E. coli and k. pneumoniae

Genotypic Characterization of Uropathogenic Escherichia coli from Companion Animals: Predominance of ST372 in Dogs and Human-Related ST73 in Cats.

Extraintestinal pathogenic Escherichia coli (ExPEC) account for over 80% and 60% of bacterial urinary tract infections (UTIs) in humans and animals, respectively. As shared uropathogenic E. coli (UPEC) strains have been previously reported among humans and pets, our study aimed to characterize E. coli lineages among UTI isolates from dogs and cats and to assess their overlaps with human UPEC lineages. We analysed 315 non-duplicate E. coli isolates from the UT of dogs (198) and cats (117) collected in central Germany in 2019 and 2020 utilizing whole genome sequencing and in silico methods. Phylogroup B2 (77.8%), dog-associated sequence type (ST) 372 (18.1%), and human-associated ST73 (16.6%), were predominant. Other STs included ST12 (8.6%), ST141 (5.1%), ST127 (4.8%), and ST131 (3.5%). Among these, 58.4% were assigned to the ExPEC group and 51.1% to the UPEC group based on their virulence associated gene (VAG) profile (ExPEC, presence of ≥VAGs: papAH and/or papC, sfa/focG, afaD/draBC, kpsMTII, and iutA; UPEC, additionally cnf1 or hlyD). Extended-spectrum cephalosporin (ESC) resistance mediated by extended-spectrum β-lactamases (ESBL) and AmpC-β-lactamase was identified in 1.9% of the isolates, along with one carbapenemase-producing isolate and one isolate carrying a mcr gene. Low occurrence of ESC-resistant or multidrug-resistant (MDR) isolates (2.9%) in the two most frequently detected STs implies that E. coli isolated from UTIs of companion animals are to a lesser extent associated with resistance, but possess virulence-associated genes enabling efficient UT colonization and carriage. Detection of human-related pandemic lineages suggests interspecies transmission and underscores the importance of monitoring companion animals.

Pseudomonasaeruginosa antimicrobial susceptibility profiles, resistance mechanisms and international clonal lineages: update from ESGARS-ESCMID/ISARPAE Group

ScopePseudomonas aeruginosa, a ubiquitous opportunistic pathogen considered one of the paradigms of antimicrobial resistance, is among the main causes of hospital-acquired and chronic infections associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial resistance through chromosomal mutations, the increasing prevalence of transferable resistance determinants (such as the carbapenemases and the extended-spectrum β-lactamases), and the global expansion of epidemic lineages. The general objective of this initiative is to provide a comprehensive update of P. aeruginosa resistance mechanisms, especially for the extensively drug-resistant (XDR)/difficult-to-treat resistance (DTR) international high-risk epidemic lineages, and how the recently approved β-lactams and β-lactam/β-lactamase inhibitor combinations may affect resistance mechanisms and the definition of susceptibility profiles. MethodsTo address this challenge, the European Study Group for Antimicrobial Resistance Surveillance (ESGARS) from the European Society of Clinical Microbiology and Infectious Diseases launched the ‘Improving Surveillance of Antibiotic-Resistant Pseudomonas aeruginosa in Europe (ISARPAE)’ initiative in 2022, supported by the Joint programming initiative on antimicrobial resistance network call and included a panel of over 40 researchers from 18 European Countries. Thus, a ESGARS-ISARPAE position paper was designed and the final version agreed after four rounds of revision and discussion by all panel members. Questions addressed in the position paperTo provide an update on (a) the emerging resistance mechanisms to classical and novel anti-pseudomonal agents, with a particular focus on β-lactams, (b) the susceptibility profiles associated with the most relevant β-lactam resistance mechanisms, (c) the impact of the novel agents and resistance mechanisms on the definitions of resistance profiles, and (d) the globally expanding XDR/DTR high-risk lineages and their association with transferable resistance mechanisms. ImplicationThe evidence presented herein can be used for coordinated epidemiological surveillance and decision making at the European and global level.

THE EFFECT OF ESCHERICHIA COLI BACTERIOPHAGE COCKTAIL ON BACTERIAL CONTAMINATION IN WATER

Objective: Wastewater and environmental water resources are treated to eliminate pathogenic microorganisms but contamination is still a significant problem. In particular, the presence of contamination with Escherichia coli (E. coli) is an important indicator of fecal contamination. Due to increasing antimicrobial resistance and failures of new antimicrobial processes, interest in bacteriophages in pathogen control has increased. Therefore, in our study, phage-based bacteria control in environmental waters was investigated as a natural solution. Material and Method: In our study, E. coli and lytic bacteriophages specific to these E. coli were isolated from environmental water samples in Ankara. The lytic activities of the isolated phages were determined on environmental and clinical extended-spectrum β-lactamases E. coli isolates. Three phages with high lytic activity were selected, and the effectiveness of the single phage and their mixtures on E. coli contamination in water was tested. Result and Discussion: As a result of the study, 17 E. coli strains were isolated from 30 environmental water samples. Lytic bacteriophages in 30 different plaque structures were also isolated from water samples. The isolated phages were found to have lytic activity in the range of 32-70% on the tested bacteria. The effectiveness of three selected phages and their cocktail on E. coli contamination in water was measured at 6th and 24th. As a result, it was observed that the cocktail application reduced the number of host bacteria in the water below detectable limits, also provided a 5-log reduction in non-host test bacteria and maintained its effect for 24 hours. When the results are evaluated, it is thought that cocktail phage application will be an effective method against E. coli contamination in water.

Phenotypic Detection of Carbapenemase and AmpC-β-Lactamase Production among Extended Spectrum β-Lactamase (ESBL)-Producing Escherichia coli and Klebsiella spp. Isolated from Clinical Specimens.

Introduction: Data on antimicrobial resistance (AMR) are sparse across numerous African countries, as microbiological analyses are not routinely conducted and surveillance data are not collected. Accordingly, clinical samples are not routinely tested for carbapenem-resistant bacteria and, therefore, the general understanding of their prevalence in the region remains limited. Methods: Between January 2020 and June 2022, we collected extended spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-PE) isolates from five hospitals in Burkina Faso. After an initial culture on ESBL-selective media, the species were identified using API20E and isolates were tested against 13 antimicrobial agents using the disc diffusion method on Mueller-Hinton (MH) agar. ESBL production was confirmed via a double-disc synergy test. Production of carbapenemases and AmpC-β-lactamases and phenotypic co-resistance were determined. Results: Among the 473 ESBL-PE, 356 were ESBL-E. coli (ESBL-Ec) and 117 were Klebsiella spp. (ESBL-K). Of these isolates, 5.3% were carbapenemase and 5.3% were AmpC-β-lactamase-positive. Three types of carbapenemases were identified: 19 NDM, 3 OXA-48-like and 1 VIM. Two isolates produced both NDM and OXA-48-like carbapenemases. Carbapenemase producers were detected at all levels of healthcare. Co-resistance rates were up to 85% for aminoglycosides, 90% for sulfonamides, 95% for fluoroquinolones and 25% for chloramphenicol. Fosfomycin resistance was 6% for ESBL-Ec and 49% for ESBL-K (49%). Conclusions: Some of the ESBL-Ec and ESBL-K co-produced carbapenemases and/or AmpC-β-lactamases at all healthcare levels and in various sample types with high co-resistance rates to non-betalactams. Carbapenem resistance is no longer rare, calling for testing in routine diagnostics, a comprehensive resistance surveillance system and infection control within healthcare.

Effect of Different Approaches to Antimicrobial Therapy with Cefmetazole and Meropenem on the Time to Defervescence in Non-Severe Extended-Spectrum β-Lactamase-Producing Escherichia coli Bacteremia.

Carbapenems are antimicrobial agents commonly used to treat extended-spectrum β-lactamase (ESBL)-producing bacteria. Although cefmetazole (CMZ) is considered effective for ESBL-producing Escherichia coli (ESBL-EC) bacteremia, previous studies showed its limitations, including the influence of the initial antimicrobial agent. Here, we examined the effects of different approaches to antimicrobial therapy with CMZ and meropenem (MEPM) on the time to defervescence in ESBL-EC bacteremia. Notably, the influence of previous antimicrobial agents was excluded. Inpatients with ESBL-EC detected in blood cultures between April 2018 and March 2023 were included and assigned to CMZ (n = 14), MEPM (n = 8), de-escalation to CMZ (dCMZ; n = 9), or escalation to MEPM (eMEPM; n = 11) groups. The median time to defervescence was 3.5, 1.0, 2.0, and 4.0 days in the CMZ, MEPM, dCMZ, and eMEPM groups, respectively, with no significant differences. Cox proportional hazards analysis showed a significant difference in the hazard ratio (95% confidence interval) of 0.378 (0.145-0.984) for the time to defervescence with CMZ versus MEPM (p = 0.046). The extent of a delayed time to defervescence is greater with early CMZ administration than with MEPM administration in patients with non-severe ESBL-EC bacteremia.

ANALYSIS OF THE DYNAMICS OF UROPATHOGENS ANTIMICROBIAL RESISTANCE IN PATIENTS OF MULTI-SPECIALTY HOSPITAL

Urinary tract infections are among the most common bacterial infections. Currently, one of the main problems of therapy, as for the infections of other localizations, is the high level of antibiotic resistance. Timely prescribed and adequately selected antimicrobial therapy is the main factor determining the treatment outcome. The aim of the study. To carry out dynamic analysis of the etiological structure of urinary tract microflora and to assess antibiotic resistance of the most significant uropathogens in patients of the Clinics of the Irkutsk State Medical University (Clinics of ISMU) in order to optimize the use of antimicrobial drugs in a multidisciplinary hospital. Materials and methods. We analyzed bacterial strains (n = 2414) collected from urine of patients treated at the Clin-ics of ISMU from 2018 to 2022. Microbiological examination of urine was conducted in bacteriological laboratory of the Clinics of ISMU. Results. During the study period, E. coli remained the main uropathogen. There has been an increase in antibiotic resistance of E. coli to the main antimicrobial agents which are traditionally used to treat urinary tract infections, including fluoroquinolones and third-generation cephalosporins. There is an increase in the frequency of detection of E. coli strains producing extended-spectrum b-lactamases from 5.4 % to 12.4 %. Meropenem and nitrofurantoin retain the greatest activity against E. coli. Conclusion. The results of this study indicate the need to strengthen control over the use of antimicrobial agents in medical organizations, the importance of constant microbiological monitoring in order to identify the characteristics of local antibiotic resistance and update protocols for empirical treatment of urinary tract infections.

Agtrevirus phage AV101 recognizes four different O-antigens infecting diverse E. coli.

Bacteriophages in the Agtrevirus genus are known for expressing multiple tail spike proteins (TSPs), but little is known about their genetic diversity and host recognition apart from their ability to infect diverse Enterobacteriaceae species. Here, we aim to determine the genetic differences that may account for the diverse host ranges of Agrevirus phages. We performed comparative genomics of 14 Agtrevirus and identified only a few genetic differences including genes involved in nucleotide metabolism. Most notably was the diversity of the tsp gene cluster, specifically in the receptor-binding domains that were unique among most of the phages. We further characterized agtrevirus AV101 infecting nine diverse Extended Spectrum β-lactamase (ESBL) Escherichia coli and demonstrated that this phage encoded four unique TSPs among Agtrevirus. Purified TSPs formed translucent zones and inhibited AV101 infection of specific hosts, demonstrating that TSP1, TSP2, TSP3, and TSP4 recognize O8, O82, O153, and O159 O-antigens of E. coli, respectively. BLASTp analysis showed that the receptor-binding domain of TSP1, TSP2, TSP3, and TSP4 are similar to TSPs encoded by E. coli prophages and distant related virulent phages. Thus, Agtrevirus may have gained their receptor-binding domains by recombining with prophages or virulent phages. Overall, combining bioinformatic and biological data expands the understanding of TSP host recognition of Agtrevirus and give new insight into the origin and acquisition of receptor-binding domains of Ackermannviridae phages.