Genetic characterization of extended-spectrum β-Lactamase- and carbapenemase-producing Escherichia coli isolated from Egyptian hospitals and environments

Correction: Genetic characterization of extended-spectrum β-Lactamase- and carbapenemase-producing Escherichia coli isolated from Egyptian hospitals and environments

[This corrects the article DOI: 10.1371/journal.pone.0255219.].

Correlation between antimicrobial resistance, biofilm formation, and virulence determinants in uropathogenic Escherichia coli from Egyptian hospital

BACKGROUND

Uropathogenic Escherichia coli (UPEC) is the main etiological agent behind community-acquired and hospital-acquired urinary tract infections (UTIs), which are among the most prevalent human infections. The management of UPEC infections is becoming increasingly difficult owing to multi-drug resistance, biofilm formation, and the possession of an extensive virulence arsenal. This study aims to characterize UPEC isolates in Tanta, Egypt, with regard to their antimicrobial resistance, phylogenetic profile, biofilm formation, and virulence, as well as the potential associations among these factors.

METHODS

One hundred UPEC isolates were obtained from UTI patients in Tanta, Egypt. Antimicrobial susceptibility was assessed using the Kirby-Bauer method. Extended-spectrum β-lactamases (ESBLs) production was screened using the double disk synergy test and confirmed with PCR. Biofilm formation was evaluated using the microtiter-plate assay and microscopy-based techniques. The phylogenetic groups of the isolates were determined. The hemolytic activity, motility, siderophore production, and serum resistance of the isolates were also evaluated. The clonal relatedness of the isolates was assessed using ERIC-PCR.

RESULTS

Isolates displayed elevated resistance to cephalosporins (90-43%), sulfamethoxazole-trimethoprim (63%), and ciprofloxacin (53%). Ninety percent of the isolates were multidrug-resistant (MDR)/ extensively drug-resistant (XDR) and 67% produced ESBLs. Notably, there was an inverse correlation between biofilm formation and antimicrobial resistance, and 31%, 29%, 32%, and 8% of the isolates were strong, moderate, weak, and non-biofilm producers, respectively. Beta-hemolysis, motility, siderophore production, and serum resistance were detected in 64%, 84%, 65%, and 11% of the isolates, respectively. Siderophore production was correlated to resistance to multiple antibiotics, while hemolysis was more prevalent in susceptible isolates and associated with stronger biofilms. Phylogroups B2 and D predominated, with lower resistance and stronger biofilms in group B2. ERIC-PCR revealed considerable diversity among the isolates.

CONCLUSION

This research highlights the dissemination of resistance in UPEC in Tanta, Egypt. The evident correlation between biofilm and resistance suggests a resistance cost on bacterial cells; and that isolates with lower resistance may rely on biofilms to enhance their survival. This emphasizes the importance of considering biofilm formation ability during the treatment of UPEC infections to avoid therapeutic failure and/or infection recurrence.

Occurrence of Imipenem-Resistant Uropathogenic Escherichia coli in Pregnant Women: An Insight into Their Virulence Profile and Clonal Structure

Uropathogenic Escherichia coli (UPEC) is the predominant pathogen in Urinary Tract Infection (UTI) in pregnant and non-pregnant women. Limited studies were initiated to explore UPEC from pregnant women with respect to imipenem resistance, pathogenicity, and their clonal lineage. In this study, imipenem resistance, phylogenetic background, virulence-associated genes, and clonal characteristics in UPECs isolated from pregnant and non-pregnant cohorts were investigated. E. coli was identified biochemically from urine culture-positive samples from pregnant and non-pregnant women. Carbapenem (meropenem, ertapenem, imipenem) susceptibility was determined by Kirby-Bauer disk diffusion test. The pathogenic determinants were identified by PCR. MEGA 11 was used to interpret clonal lineages from MLST. GraphPad Prism 8.0 and SPSS 26.0 were used for statistical interpretation. Results indicated highest resistance against imipenem compared to meropenem and ertapenem in UPECs isolated from pregnant (UPECp; 63.89%) and non-pregnant (UPECnp; 87.88%) women. Although phylogroup E was predominant in both imipenem-resistant isolates, acquisition of virulence factors was higher among UPECnp than UPECp. Akin to this observation, the presence of PAI III536 and PAI IV536 was statistically significant (p < 0.05) in the former. MLST analysis revealed similar clonal lineages between UPECnp and UPECp, which showed an overall occurrence of ST405 followed by ST101, ST410, ST131, and ST1195 in UPECnp and ST167 in UPECp, respectively, with frequent occurrence of CC131, CC405. Therefore, imipenem-resistant UPECp although discrete with respect to their virulence determinants when compared to UPECnp shared similar STs and CCs, which implied common evolutionary history. Thus, empiric treatment must be restricted in UTIs to especially protect maternal and fetal health.

Distribution of ß-Lactamase Genes Among Multidrug-Resistant and Extended-Spectrum ß-Lactamase-Producing Diarrheagenic Escherichia coli from Under-Five Children in Ethiopia

Purpose

Escherichia coli strains that produce extended-spectrum ß-lactamase (ESBL) and carbapenemase are among the major threats to global health. The objective of the present study was to determine the distribution of ß-lactamase genes among multidrug-resistant (MDR) and ESBL-producing Diarrheagenic E. coli (DEC) pathotypes isolated from under-five children in Ethiopia.

Patients and Methods

A cross-sectional study was conducted in Addis Ababa and Debre Berhan, Ethiopia. It was a health-facility-based study and conducted between December 2020 and August 2021. A total of 476 under-five children participated in the study. DEC pathotypes were detected by conventional Polymerase Chain Reaction (PCR) assay. After evaluating the antimicrobial susceptibility profile of the DEC strains by disk diffusion method, confirmation test was done for ESBL and carbapenemase production. ß-lactamase encoding genes were identified from phenotypically ESBLs and carbapenemase positive DEC strains using PCR assay.

Results

In total, 183 DEC pathotypes were isolated from the 476 under-five children. Seventy-nine (43%, 79/183) MDR-DEC pathotypes were identified. MDR was common among enteroaggregative E. coli (EAEC) (58%, 44/76), followed by enterotoxigenic E. coli (ETEC) (44%, 17/39)) and enteroinvasive E. coli (EIEC) (30%, 7/23). Phenotypically, a total of 30 MDR-DEC pathotypes (16.4%, 30/183) were tested positive for ESBLs. Few ETEC (5.1%, 2/39) and EAEC (2.6%, 2/76) were carbapenemase producers. The predominant β-lactamase genes identified was blaTEM (80%, 24/30) followed by blaCTX-M (73%, 22/30), blaSHV (60%, 18/30), blaNDM (13%, 4/30), and blaOXA-48 (13%, 4/30). Majority of the ß-lactamase encoding genes were detected in EAEC (50%) and ETEC (20%). Co-existence of different β-lactamase genes was found in the present study.

Conclusion

The blaTEM, blaCTX-M, blaSHV, blaNDM, and blaOXA-48, that are associated with serious and urgent threats globally, were detected in diarrheagenic E. coli isolates from under-five children in Ethiopia. This study also revealed the coexistence of the β-lactamase genes.

Phylotypic Profiling, Distribution of Pathogenicity Island Markers, and Antimicrobial Susceptibility of Escherichia coli Isolated from Retail Chicken Meat and Humans

Escherichia coli (E.coli) found in retail chicken meat could be causing a wide range of infections in humans and constitute a potential risk. This study aimed to evaluate 60 E. coli isolates from retail chicken meat (n = 34) and human urinary tract infections (UTIs, n = 26) for phylogenetic diversity, presence of pathogenicity island (PAI) markers, antimicrobial susceptibility phenotypes, and antimicrobial resistance genes, and to evaluate their biofilm formation capacity. In that context, confirmed E.coli isolates were subjected to phylogrouping analysis using triplex PCR, antimicrobial susceptibility testing using the Kirby–Bauer disc diffusion method; PAI distribution was investigated by using two multiplex PCRs. Most of the chicken isolates (22/34, 64.7%) were identified as commensal E. coli (A and B1), while 12 isolates (35.3%) were classified as pathogenic virulent E. coli (B2 and D). Similarly, the commensal group dominated in human isolates. Overall, 23 PAIs were detected in the chicken isolates; among them, 39.1% (9/23) were assigned to group B1, 34.8% (8/23) to group A, 4.34% (1/23) to group B2, and 21.7% (5/23) to group D. However, 25 PAIs were identified from the human isolates. PAI IV536 was the most prevalent (55.9%, 69.2%) PAI detected in both sources. In total, 37 (61.7%) isolates of the chicken and human isolates were biofilm producers. Noticeably, 100% of E. coli isolates were resistant to penicillin and rifamycin. Markedly, all E. coli isolates displayed multiple antibiotic resistance (MAR) phenotypes, and the multiple antibiotic resistance index (MARI) among E. coli isolates ranged between 0.5 and 1. Several antibiotic resistance genes (ARGs) were identified by a PCR assay; the sul2 gene was the most prevalent (38/60, 63.3%) from both sources. Interestingly, a significant positive association (r = 0.31) between biofilm production and resistance to quinolones by the qnr gene was found by the correlation analysis. These findings were suggestive of the transmission of PAI markers and antibiotic resistance genes from poultry to humans or humans to humans through the food chain. To avoid the spread of virulent and multidrug-resistant E. coli, intensive surveillance of retail chicken meat markets is required.

Virulence-associated genes analysis of carbapenemase-producing Escherichia coli isolates

Carbapenem-resistant Escherichia coli has emerged as a major public health issue across the world. This study was aimed to determine the virulence content and phylogenetic groups of carbapenemase-producing E. coli isolates in southwest Iran. One hundred and fifty-two non-duplicate E. coli isolates were collected from various clinical samples. Antibiotic susceptibility and minimum inhibitory concentrations (MIC) were determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines by Kirby-Bauer disc diffusion and agar dilution methods. Phenotypic screening of carbapenemase enzymes was performed by modified Hodge test (MHT). Detection of carbapenemase genes, phylogenetic groups, and virulence-associated genes were also performed by the PCR assay. The highest and lowest resistance rates were observed against mezlocillin (70.4%) and doripenem (13.1%), respectively. Out of 28 isolates that were resistant to carbapenem antibiotics, 12 (7.9%) strains were phenotypically carbapenemase producers. The bla_OXA-48 was the predominant carbapenemase gene, detected in 58.3% of isolates, followed by bla_IMP (41.7%) and bla_NDM (8.3%). None of the isolates harbored bla_VIM and bla_KPC genes. Among the twelve carbapenemase-producing strains, urinary isolates were mostly classified into B2 (41.7%) and D (25%) phylogenetic groups, while other clinical isolates belonged to B1 (25%) and A (8.3%) groups. The frequency of virulence-associated genes was also investigated in all isolates and ranged from 6.6% for hly to 75% for fimA. The emergence of carbapenemase-producing strains is a growing concern to public health. Therefore, the proper implementation of monitoring programs is crucial for limiting their dissemination.

Gut Commensal Escherichia coli, a High-Risk Reservoir of Transferable Plasmid-Mediated Antimicrobial Resistance Traits

Background

Escherichia coli (E. coli), the main human gut microorganism, is one of the evolved superbugs because of acquiring antimicrobial resistance (AMR) determinants via horizontal gene transfer (HGT).

Purpose

This study aimed to screen isolates of gut commensal E. coli from healthy adult individuals for antimicrobial susceptibility and plasmid-mediated AMR encoding genes.

Methods

Gut commensal E. coli bacteria were isolated from fecal samples that were taken from healthy adult individuals and investigated phenotypically for their antimicrobial susceptibility against diverse classes of antimicrobials using the Kirby Bauer disc method. PCR-based molecular assays were carried out to detect diverse plasmid-carried AMR encoding genes and virulence genes of different E. coli pathotypes (eaeA, stx, ipaH, est, elt, aggR and pCVD432). The examined AMR genes were β-lactam resistance encoding genes (bla_CTX-M1, bla_TEM, bla_CMY-2), tetracycline resistance encoding genes (tetA, tetB), sulfonamides resistance encoding genes (sul1, sulII), aminoglycoside resistance encoding genes (aac(3)-II, aac(6′)-Ib-cr) and quinolones resistance encoding genes (qnrA, qnrB, qnrS).

Results

PCR results revealed the absence of pathotypes genes in 56 isolates that were considered gut commensal isolates. E. coli isolates showed high resistance rates against tested antimicrobial agents belonging to both β-lactams and sulfonamides (42/56, 75%) followed by quinolones (35/56, 62.5%), tetracyclines (31/56, 55.4%), while the lowest resistance rate was to aminoglycosides (24/56, 42.9%). Antimicrobial susceptibility profiles revealed that 64.3% of isolates were multidrug-resistant (MDR). High prevalence frequencies of plasmid-carried AMR genes were detected including bla_TEM (64%) sulI (60.7%), qnrA (51.8%), aac(3)-II (37.5%), and tetA (46.4%). All isolates harbored more than one gene with the most frequent genetic profile among isolates was bla_TEM-bla_CTX-M1-like-qnrA-qnrB-tetA-sulI.

Conclusion

Results are significant in the evaluation of plasmid-carried AMR genes in the human gut commensal E. coli, suggesting a potential human health risk and the necessity of strict regulation of the use of antibiotics in Egypt. Commensal E. coli bacteria may constitute a potential reservoir of AMR genes that can be transferred to other bacterial species.

Prevalence of common carbapenemase genes and multidrug resistance among uropathogenic Escherichia coli phylogroup B2 isolates from outpatients in Wasit Province/ Iraq

Carbapenems are the last resort antimicrobials for the treatment of extended spectrum β-lactamases (ESBLs) producing Enterobacteriaceae. Emergence of carbapenems resistant group B2 uropathogenic E. coli (UPEC) is a major concern because of their high virulence. Prevalence of these enzymes and multidrug resistance (MDR) among B2 UPEC isolates from Iraqi outpatients with acute urinary tract infection (UTI) was evaluated in this research. Urine cultures were performed and the isolates were identified biochemically. Escherichia coli isolates were tested for phylogroup reference by quadraplex PCR, then B2 isolates were detected for antimicrobial resistance by disc diffusion test and carbapenemase genes by PCR. Escherichia coli was the most prevalent among Gram-negative isolates (66.6%) and B2 was the most detected phylogroup among E. coli isolates (33.9%). Most of B2 isolates showed high resistance rates to tested antimicrobials, especially β-lactams with MDR revealed in 100% of them. Whereas, low resistance rates were noted against carbapenems, aminoglycosides and nitrofurantoin. Carbapenemase genes were detected in 76.3% of B2 isolates. Of which, blaOXA-48 was the most frequent (57.8%), followed by blaPER (47.3%), blaKPC (15.7%), blaVEB and blaVIM (10.5%, for each). Whereas, blaGES and blaIMP genes were not found. Coproduction of these genes occurred among 17 isolates. The combination of blaOXA-48 and blaPER was the most frequent (41.1%). All carbapenemase producing isolates were MDR. These results revealed high prevalence of carbapenemase genes and MDR among B2 UPEC recovered in this study. In the study area. it is strongly advised to use aminoglycosides and nitrofurantoin for empirical treatment of UPEC.