Multi-drug resistance and biofilm production among diarrheagenic Escherichia coli pathotypes isolated from stools of children with acute diarrheal disease

Abstract

Background. Diarrheagenic E. coli (DEC) is an etiological agent of childhood diarrhea. Resistance against commonly used drugs in the empirical treatment of enteric infections has increased among DEC. Relationship between antibiotic resistance and biofilm formation in microorganisms have been widely reported. This study was aimed to determine the antibiotic resistance and biofilm production pattern among DEC pathotypes isolated from stools of children aged 0–5 years with acute diarrheal disease in Abakaliki, Nigeria. Materials and methods. Diarrheal stool samples were obtained from 60 children and E. coli were isolated and identified using standard guidelines provided for laboratory diagnosis of enteric pathogens. Molecular identification was done by amplification of E. coli universal stress protein A (uspA) using polymerase chain reaction (PCR) method. Detection of virulent genes of DEC pathotypes was performed in a group of multiplex PCR using their specific primers. Kirby–Bauer disk diffusion method was used to determine the antibiotic susceptibility patterns of the isolates while biofilms production was detected by thiazolyl blue tetrazolium bromide dye in a 96-well plate. Results. DEC was isolated in 40 stools among which EIEC [40% (n = 16)] was commonly detected followed by ETEC [30% (n = 12)], EAEC [20% (n = 8)] and typical EPEC [10% (n = 4)]. Half of EAEC showed the highest multidrug resistance against ampicillin, cefoxitin, ciprofloxacin, levofloxacin, and tetracycline with the strongest biofilm production followed by all the EPEC which were resistant to ampicillin, ciprofloxacin, levofloxacin, and tetracycline with moderate biofilm production. All the LT-ETEC exhibited the least resistance to ampicillin and tetracycline with the weakest biofilm production. Conclusion. High frequency of the EIEC pathotype suggests its role as the primary etiological agent of diarrhea in children. Correlation between high drug resistance and biofilm production among the pathotype may indicate that biofilms may provide compatible uptake of resistance genes.