Monitoring of diarrheagenic Escherichia coli infections in patients in Guangdong Province during 2013 to 2016

Abstract

Objective To investigate the infection status, serotype distribution, drug sensitivity and molecular characteristics of diarrheagenic Escherichia coli (DEC) in patients with diarrhea in Guangdong Province. Methods Fecal samples were collected, cultured and isolated by traditional methods. Suspected Escherichia coli isolates were confirmed by multiplex PCR used for detecting specific virulence genes and biochemical methods. Positive strains were serotyped, characterized for drug sensitivity and analyzed by pulsed-field gel electrophoresis (PFGE). Results The total positive rate of DEC in patients with diarrhea was 6.26%. The positive rates of enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enterohemorrhagic Escherichia coli (EHEC), enteroadherent Escherichia coli (EAEC) and enteroinvasive Escherichia coli (EIEC) were 2.47%, 1.54%, 1.32%, 0.62% and 0.09%, respectively, with infections primarily in children aged 0-<7 years. The total seropositive rate was 52.54%, with EHEC accounting for 15.00%. DEC showed high sensitivity to imipenem, ciprofloxacin, ceftazidime and cefotaxime. The multidrug resistance rate of DEC was 58.45%, with EPEC being the most serious for multidrug resistance. PFGE results showed that ETEC, EHEC, EPEC and EAEC had a high degree of polymorphism. Conclusion EPEC is the predominant type of DEC circulating in Guangdong Province. Third-generation cephalosporins are the first drugs of choice for treating infections in children. Ciprofloxacin can be used to treat adults. The problem of multiple drug resistance of DEC is severe and efforts to monitor DEC infections and drug resistance should be strengthened. Key words: Diarrheagenic Escherichia coli; Virulence gene; Pathogen surveillance; Antibiotic resistance surveillance; Pulsed-field gel electrophoresis