Serotypes, genotypes and antimicrobial resistance patterns of human diarrhoeagenic Escherichia coli isolates circulating in southeastern China

Abstract

Diarrhoeagenic Escherichia coli (DEC) infection is a major health problem in developing countries. The prevalence and characteristics of DEC have not been thoroughly investigated in China. Consecutive faecal specimens from outpatients with acute diarrhoea in nine sentinel hospitals in southeastern China were collected from July 2009 to June 2011. Bacterial and viral pathogens were detected by culture and RT‐PCR, respectively. DEC isolates were further classified into five pathotypes using multiplex PCR. The O/H serotypes, sequence types (STs) and antimicrobial susceptibility profiles of the DEC isolates were determined. A total of 2466 faecal specimens were collected, from which 347 (14.1%) DEC isolates were isolated. DEC was the dominant bacterial pathogen detected. The DEC isolates included 217 EAEC, 62 ETEC, 52 EPEC, 14 STEC, one EIEC and one EAEC/ETEC. O45 (6.6%) was the predominant serotype. Genotypic analysis revealed that the major genotype was ST complex 10 (87, 25.6%). Isolates belonging to the serogroups or genotypes of O6, O25, O159, ST48, ST218, ST94 and ST1491 were highly susceptible to the majority of antimicrobials. In contrast, isolates belonging to O45, O15, O1, O169, ST38, ST226, ST69, ST31, ST93, ST394 and ST648 were highly resistant to the majority of antimicrobials. DEC accounted for the majority of bacterial pathogens causing acute diarrhoea in southeastern China, and it is therefore necessary to test for all DEC, not only the EHEC O157:H7. Some serogroups or genotypes of DEC were highly resistant to the majority of antimicrobials. DEC surveillance should be emphasized.

Molecular analysis and antimicrobial susceptibility of enterotoxigenic Escherichia coli from diarrheal patients

“…PFGE and MLST have been used to study the genetic relationships of ETEC and generate data in the format of electrophoretogram or nucleotide sequences that are electronically available on the E. coli PulseNet/ MLST database, making it possible to make comparisons. Genotypes ST-94, ST-1491, ST-218, and ST-69 detected in our collection have also been reported in DEC isolates from the adjacent Zhejiang Province (Chen et al, 2014). The 12 isolates of ST-2332 were all recovered from diarrheal infants aged b2 years.…”

“…A retrospective study on human DEC in Zhejiang Province also highlighted the challenge of DEC infections in China (Chen et al, 2014). However, little is known about the genotypic and phenotypic characteristics of this pathogen in China.…”

Current perspectivesin pathogenesis and antimicrobial resistance of enteroaggregative Escherichia coli

“…Similar studies from China [48] and Nicaragua [49] have shown the trend in emergence of multidrug-resistant strains. Chen et al [48] investigated 347 DEC isolates from southeast China and found the multidrug resistance phenotype for 70.2%; in addition, 91.8% of these strains from Chinese patients were resistant to ampicillin, which was higher than the rate reported from the Nicaraguan study (67.7%) [49] and the Iranian study (62.0%) [50]. The Nicaraguan and Iranian studies also showed similar resistance rates for tetracycline and trimethoprim-sulfamethoxazole (>50%).…”

“…The Nicaraguan and Iranian studies also showed similar resistance rates for tetracycline and trimethoprim-sulfamethoxazole (>50%). Finally, the study from southeast China by Chen et al [48] showed the effect of DEC serotype and genotype on resistance, demonstrating that O6, O25, O159, ST48, ST218, ST94 and ST1491 were sensitive to most antibiotics, while O45, O15, O1, O169, ST38, ST226, ST69, ST31, ST93, ST394 and ST648 were highly resistant to most antibiotics.…”

Public health risks associated with Enteroaggregative Escherichia coli (EAEC) as a food‐borne pathogen

“…Over 70% of isolates exhibited multiple drug resistance and over 90% of isolates were resistant to ampicillin (Chen et al, 2014).…”