Molecular Epidemiology of Extended-Spectrum β-Lactamase–Producing Escherichia coli Pathotypes in Diarrheal Children from Low Socioeconomic Status Communities in Bihar, India: Emergence of the CTX-M Type

Abstract

Background:Childhood diarrheal diseases remain highly endemic in India, but the emergence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli among children with diarrhea in Bihar remains elusive. In this study, we determine and characterize ESBL-producing E coli pathotypes among hospitalized diarrheal preschool children living in low socioeconomic level communities in Bihar, India.Materials and methods:The stool samples were collected everyday throughout the year for 2 consecutive years. In our study, we collected stool samples randomly from every fifth patient. Stool samples were collected from a total of 633 randomly selected diarrheal children (age: 0-60 months) belonging to 17 communities and screened for identification of virulent diarrheagenic E coli (DEC) pathotype (viz, enteropathogenic E coli [EPEC], enteroaggregative E coli [EAEC], enterotoxigenic E coli [ETEC], enteroinvasive E coli [EIEC], and enterohemorrhagic E coli [EHEC]) by a multiplex polymerase chain reaction (PCR) assay. Furthermore, ESBLs were screened by conventional antibiotic resistance pattern testing and later characterized for the presence of β-lactamase (bla) genes by PCR and DNA sequencing.Results:Diarrheagenic E coli was detected in 191 cases (30.2%) of the total 633 diarrheic children. Maximum occurrence of DEC was found in ≤12 months age group (72.7%) with prevalence of the EAEC pathotype. Most isolates were resistant to ampicillin, ciprofloxacin, piperacillin, levofloxacin, ceftazidime, cefotaxime, ceftriaxone, and gentamicin, whereas over 96% of them were sensitive to amikacin. About 37.6% of total 191 DEC isolates were ESBL producers (n = 72), being prevalent among ETEC (n = 35; 18.32%), followed by EPEC (n = 21; 10.9%), EAEC (n = 13; 6.8%), and EIEC (n = 3; 1.57%). Interestingly, the commonest β-lactamase was CTX-M type (blaCTX-M) in 86.1% (n = 62) of the ESBL isolates, followed by blaSHV (n = 49; 68%), blaTEM (n = 37; 51.8%), and blaOXA (n = 21; 29.1%) determinants. Resistance of ESBL isolates was mostly related to ampicillin (100%), ceftriaxone (98.1%), cefotaxime (92.4%), gentamicin (74.1%), and levofloxacin (73.2%), whereas best antimicrobial activities were observed for piperacillin-tazobactam, amikacin, meropenem, and imipenem.Conclusions:This study revealed that EAEC (72.1%) is the predominant pathotype in Bihar, significantly high in ≤12 months age group children (P = .04). Moreover, the widespread prevalence of ESBLs in children, especially the CTX-M type, is of great concern, which requires monitoring of infection control measures through efficient antimicrobial management and detection of ESBL-producing isolates.

Virulence gene profiles and molecular genetic characteristics of diarrheagenic Escherichia coli from a hospital in western China

“…DEC occurrence in our study was higher than in Beijing (4.6%) [ 58 ] and the southeast coast (7.6%) of China [ 67 ]. In contrast, the detected rate of DEC was 30.2% in India [ 68 ], 39% in Brazil [ 69 ], and 30% in Peru [ 70 ], much higher than the rate in this study. These results suggest that the occurrence of DEC is comparatively low in China.…”

Antibiotic Resistance Profile and Clonality of E. coli Isolated from Water and Paediatric Stool Samples in the North-West, Province South Africa

“…These pathotypes include the EPEC (Enteropathogenic E. coli), STEC (Shiga toxinproducing E. coli or EHEC (Enterohaemorrhagic E. coli)), ETEC (Enterotoxigenic E. coli), EIEC (Enteroinvasive E. coli), EAEC (Enteroaggregative E. coli) 9 and recently, DAEC (Diffusely-adherent E. coli) 10 . Each pathotype has its unique virulenceassociated gene(s) (VGs) contributing to its disease-causing potentials 11 .…”

“…ETEC pathotypes are the cause of childhood diarrhoea in many developing countries. Also, a few foodborne outbreaks due to ETEC have been recorded in some developed countries 5,11,21,22 . ETEC pathotypes induce infection by attaching to the intestinal cell surface, and secreting either the heat stable (ST) or labile (LT) enterotoxin (or both) which are plasmid encoded 23 .…”

“…Phenotypic multi-drug resistance of some organisms including pathogenic E. coli emerged because of a metallo-β-lactamase gene possessed by these strains. This gene plays an active role in hydrolysing all β-lactam antibiotics except aztreonam 34 and it is said to confer resistance to other antibiotics in E. coli 11,21 . In pathogenic E. coli, the most essential resistance mechanism against β-lactams involves plasmid-encoded extended-spectrum β-lactamases (ESBLs) 33,35 .…”

“…ESBL-producing E. coli hydrolyses penicillin, extended spectrum Cephalosporins and the monobactams 19,21 but cannot efficiently degrade Cephamycin, Carbapenems and β-lactamase inhibitors 19,36 . However, resistant strains have emerged 11 . There are different groups of ESBLs including CTX-M, CMY, SHV and DHA [37][38][39] .…”