A study of virulence and antimicrobial resistance pattern in diarrhoeagenic Escherichia coli isolated from diarrhoeal stool specimens from children and adults in a tertiary hospital, Puducherry, India|
Natarajan, Mailan; Kumar, Deepika; Mandal, Jharna; Biswal, Niranjan & Stephen, Selvaraj
Background: Emergence of atypical enteropathogenic Escherichia coli (EPEC) and hybrid E. coli (harboring genes of
more than one DEC pathotypes) strains have complicated the issue of growing antibiotic resistance in diarrhoeagenic
Escherichia coli (DEC). This ongoing evolution occurs in nature predominantly via horizontal gene transfers involving
the mobile genetic elements like integrons notably class 1 integron. This study was undertaken to determine the
virulence pattern and antibiotic resistance among the circulating DEC strains in a tertiary care center in south of India.
Methods: Diarrhoeal stool specimens were obtained from 120 children (< 5 years) and 100 adults (> 18 years),
subjected to culture and isolation of diarrhoeal pathogens. Conventional PCR was performed to detect 10 virulence
and 27 antimicrobial resistance (AMR) genes among the E. coli isolated.
Results: DEC infection was observed in 45 (37.5%) children and 18 (18%) adults, among which [18 (40%), 10 (10%)]
atypical EPEC was most commonly detected followed by [6 (13.3%), 4 (4%)] ETEC, [5 (11.1%) 2 (2%)] EAEC, [(3 (6.6%),
0 (0%)] EIEC, [3 (6.6%), 0 (0%] typical EPEC, and [4 (8.8%), 1 (1%)] STEC, and no NTEC and CDEC was detected. DEC
co-infection in 3 (6.6%) children, and 1(1%) adult and sole hybrid DEC infection in 3 (6.6%) children was detected.
The distribution of sulphonamide resistance genes (sulI, sulII, and sulIII were 83.3 and 21%, 60.41 and 42.1%, and 12.5
and 26.3%, respectively) and class 1 integron (int1) genes (41.6 and 26.31%) was higher in DEC strains isolated from
children and adults, respectively. Other AMR genes detected were qnrS, qnrB, aac(6’)Ib-cr, dhfr1, aadB, aac(3)-IV, tetA,
tetB, tetD, catI, blaCTX, blaSHV, and blaTEM. None harbored qnrA, qnrC, qepA, tetE, tetC, tetY, ermA, mcr1, int2,
and int3 genes.
Conclusions: Atypical EPEC was a primary etiological agent of diarrhea in children and adults among the
DEC pathotypes. Detection of high numbers of AMR genes and class 1 integron genes indicate the importance of
mobile genetic elements in spreading of multidrug resistance genes among these strains.
Diarrhoeagenic Escherichia coli (DEC); Diarrhea; Children; Adults; Antimicrobial resistance (AMR) genes