Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam.
Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E. coli O104:H4 in Europe in 2011. We assessed the opportunities for E. coli carrying the aggR and stx genes to emerge in 'backyard' farms in south-east Asia.



Faecal samples collected from 204 chicken farms; 204 farmers and 306 age- and gender-matched individuals not exposed to poultry farming were plated on MacConkey agar plates with and without antimicrobials being supplemented. Sweep samples obtained from MacConkey agar plates without supplemented antimicrobials were screened by multiplex PCR for the detection of the stx1, stx2 and aggR genes. One chicken farm sample each (0.5 %) contained the stx1 and the aggR gene. Eleven (2.4 %) human faecal samples contained the stx1 gene, 2 samples (0.4 %) contained stx2 gene, and 31 (6.8 %) contained the aggR gene. From 46 PCR-positive samples, 205 E. coli isolates were tested for the presence of stx1, stx2, aggR, wzx O104 and fliC H4 genes. None of the isolates simultaneously contained the four genetic markers associated with E. coli O104:H4 epidemic strain (aggR, stx2, wzx O104 and fliC H4 ). Of 34 EAEC, 64.7 % were resistant to 3(rd)-generation cephalosporins.



These results indicate that in southern Vietnam, the human population is a more likely reservoir of aggR and stx gene carrying E. coli than the chicken population. However, conditions for transmission of isolates and/or genes between human and animal reservoirs resulting in the emergence of highly virulent E. coli strains are still favorable, given the nature of'backyard' farms in Vietnam.
Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. trungnv@oucru.org.|Department of Global Health-Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands. trungnv@oucru.org.|Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam. trungnv@oucru.org.
Nguyen Vinh
NV
Trung
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.
Hoang Ngoc
HN
Nhung
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
Juan J
JJ
Carrique-Mas
Sub-Department of Animal Health, My Tho, Tien Giang, Vietnam.
Ho Huynh
HH
Mai
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.
Ha Thanh
HT
Tuyen
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
James
J
Campbell
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.
Nguyen Thi
NT
Nhung
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.
Pham
P
Van Minh
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.|Central Veterinary Institute of Wageningen UR, Lelystad, The Netherlands.
Jaap A
JA
Wagenaar
Preventive Medicine Center, My Tho, Tien Giang, Vietnam.
Nguyen Thi Nhu
NT
Mai
Sub-Department of Animal Health, My Tho, Tien Giang, Vietnam.
Thai Quoc
TQ
Hieu
Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.|Department of Global Health-Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.|Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.
Constance
C
Schultsz
Oxford University Clinical Research Unit, Centre for Tropical Medicine, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
Ngo Thi
NT
Hoa
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002511:Cephalosporins / Q000494:pharmacology; D002645:Chickens / Q000382:microbiology; D003967:Diarrhea / Q000453:epidemiology; D004196:Disease Outbreaks; D004197:Disease Reservoirs / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics; D000067565:Farmers; D000072480:Farms; D005243:Feces / Q000382:microbiology; D005408:Flagellin / Q000235:genetics; D005516:Food Microbiology; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics; D008826:Microbial Sensitivity Tests; D060885:Multiplex Polymerase Chain Reaction / Q000662:veterinary; D011200:Poultry / Q000382:microbiology; D015995:Prevalence; D022621:Shiga Toxin / Q000235:genetics; D022622:Shiga Toxin 1 / Q000235:genetics; D022641:Shiga Toxin 2 / Q000235:genetics; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D015534:Trans-Activators / Q000235:genetics; D014744:Vietnam / Q000453:epidemiology; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000378:metabolism
C088603:AggR protein, E coli; D000890:Anti-Infective Agents; D002511:Cephalosporins; D029968:Escherichia coli Proteins; C516095:FliC protein, E coli; D005819:Genetic Markers; D026901:Membrane Transport Proteins; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2; D015534:Trans-Activators; D037521:Virulence Factors; C543926:Wzx protein, E coli; D005408:Flagellin; D022621:Shiga Toxin; D001618:beta-Lactamases
Chicken; E. coli; EAEC; Humans; STEC; Vietnam