Distribution of virulence factors and its relatedness towards the antimicrobial response of enterotoxigenic Escherichia coli strains isolated from patients in Kolkata, India

Abstract

Aim: Enterotoxigenic Escherichia coli (ETEC) is one of the most widely recognized diarrhoeal pathogens in developing countries. The advancement of ETEC vaccine development depends on the antigenic determinants of the ETEC isolates from a particular geographical region. So, the aim here was to comprehend the distribution of virulence determinants of the clinical ETEC strains of this region. Additionally, an attempt was made to find any correlation with the antimicrobial response pattern. Methods and results: Multiplex PCR was employed to identify virulence determinants followed by confirmatory singleplex PCR. For observation of antibiotic response, the Kirby-Bauer method was used. Out of 379 strains, 46% of strains harboured both the enterotoxins ST and LT, whereas 15% were LT only. Among the major colonization factors (CFs), CS6 (41%) was the most prevalent followed by CFA/I (35%) and CFA/ III was the lowest (3%). Among the minor CFs, CS21 (25%) was most prevalent, while CS15 showed the lowest (3%) presence. Among the non-classical virulence factors, EatA (69%) was predominant. ETEC strains harbouring CS6 showed resistance towards the commonly used drug Ciprofloxacin (70%). Conclusion: CS6 and elt+est toxin genes co-occurred covering 51% of the isolates. CS21 was found in most strains with est genes (43%). EatA was found to occur frequently when ST was present alone or with LT. CS6-harbouring strains showed an independent correlation to antimicrobial resistance. Significance and Impact of the Study: This study would aid in identifying the commonly circulating ETEC isolates of Kolkata, India, and their prevalent virulence determinants. Knowledge of antibiotic resistance patterns would also help in the appropriate use of antibiotics. Furthermore, the study would aid in identifying the multivalent antigens suitable for region-specific ETEC vaccines with maximum coverage.

Genotyping Based on CRISPR Loci Diversity and Pathogenic Potential of Diarrheagenic Escherichia coli

“…ETEC is the most common cause of traveler’s diarrhea and rarely found in meat products, and contaminated food and water have been implicated as vehicles for transmission of ETEC infection. Moreover, ETEC has been studied in India, the United States, and other regions ( Daniels, 2005 ; Crofts et al, 2018 ; Mondal et al, 2022 ). While the amount of ETEC collected in this study was limited and originated from Bangladesh, the United States, China, Chile, and other countries, it was impossible to evaluate the geographical specificity of strains in each region.…”

Clinical and Molecular Analysis of ST11-K47 Carbapenem-Resistant Hypervirulent Klebsiella pneumoniae: A Strain Causing Liver Abscess

“…CofT has a lysozyme-like domain and produces type 4b pilus CFA/III lytic transglycosylase. CFA/III is a colonization factor antigen (CFA) group that assists the release of enterotoxins by attaching to the epithelium of the small intestine in Enterotoxigenic Escherichia coli (ETEC) [23,24]. Its homology genes, IagB of Salmonella enterica serovar Typhi and IpgF of S. flexneri, participate in the invasion of eukaryotic host cells [25].…”

Repeat modules and N-linked glycans define structure and antigenicity of a critical enterotoxigenicE. coli adhesin

“…In exploring the utility of EtpA as a potential vaccine antigen, studies to date have demonstrated that the etpBAC locus is highly conserved across ETEC from geographically disparate origins [25][26][27][28][29][30] , is immunogenic following natural 27,30 and human experimental challenge 31,32 infections, and that immunization with recombinant EtpA (rEtpA) affords considerable protection against intestinal colonization 21,27,29,33 19,34-37 . In addition, EtpA expression by ETEC strains is strongly associated with the development of diarrheal illness in young children, while antibodies against EtpA are associated with protection 30 .…”