Prevalence of carbapenem resistance and its potential association with antimicrobial use in humans and animals in rural communities in Vietnam

Abstract

Background: Vietnam and Southeast Asia are hotspots for antimicrobial resistance; however, little is known on the prevalence of carriage of carbapenem resistance in non-hospitalized humans and in animals. Carbapenem-resistant Enterobacteriaceae (CRE), particularly Escherichia coli (CREC) and Klebsiella pneumoniae (CRKP) and also Acinetobacter baumannii (CRAB) are emerging threats worldwide.

Methods: We investigated healthy humans (n = 652), chickens (n = 237), ducks (n = 150) and pigs (n = 143) in 400 small-scale farms in the Mekong Delta of Vietnam. Samples (rectal swabs, faecal swabs) were investigated for carriage of CRE/CRAB and were further characterized phenotypically and genotypically.

Results: In the Mekong Delta of Vietnam, the prevalence of CRE isolates in human rectal swabs was 0.6%, including 4 CREC and 1 CRKP. One pig was infected with CREC (prevalence 0.7%). CRAB was isolated from chickens (n = 4) (prevalence 2.1%) and one duck (prevalence 0.7%). CRKP was isolated from a human who was also colonized with CREC. The CRKP strain (ST16), from an 80 year-old person with pneumonia under antimicrobial treatment, genetically clustered with clinical strains isolated in a hospital outbreak in southern Vietnam. The prevalence of CRE was higher among humans that had used antimicrobials within 90 days of the sampling date than those had not (4.2% versus 0.2%) (P = 0.005). All CRE/CRAB strains were MDR, although they were susceptible to colistin and neomycin. The carbapenemase genes identified in study strains were bla _NDM and bla _OXA.

Conclusions: The finding of a CRKP strain clustering with previous hospital outbreak raises concerns about potential transmission of carbapenem-resistant organisms from hospital to community settings or vice-versa.

Figure 1.

Map showing the collection sites and samples in Dong Thap province.

Figure 2.

Distribution of carbapenem and other antimicrobial resistance genes in CREC/CRKP/CRAB isolates from humans and animals in Dong Thap province (Vietnam). Colour code: yellow, human isolate; grey, animal isolate. Genes are grouped by encoding resistant to β-lactams, fluoroquinolones (Flq), aminoglycosides (Agly), macrolide/lincosamide/streptogramin (MLS), phenicols (Phe), rifampicin (Rif), sulphonamides (Sul), tetracyclines (Tet), and trimethoprim (Tmt). Isolate species: EC, E. coli; KP, K. pneumoniae; AB, A. baumannii. Subscripts indicate individual samples/subjects. H, human; P, pig; C, chicken; D, duck.

Figure 3.

Phylogenetic structure of K. pneumoniae ST16 from a human carrier and bloodstream infections.