Emergence of carbapenem-resistant Acinetobacter baumannii as the major cause of ventilator-associated pneumonia in intensive care unit patients at an infectious disease hospital in southern Vietnam

Abstract

Ventilator-associated pneumonia (VAP) is a serious healthcare-associated infection that affects up to 30 % of intubated and mechanically ventilated patients in intensive care units (ICUs) worldwide. The bacterial aetiology and corresponding antimicrobial susceptibility of VAP is highly variable, and can differ between countries, national provinces and even between different wards in the same hospital. We aimed to understand and document changes in the causative agents of VAP and their antimicrobial susceptibility profiles retrospectively over an 11 year period in a major infectious disease hospital in southern Vietnam. Our analysis outlined a significant shift from Pseudomonas aeruginosa to Acinetobacter spp. as the most prevalent bacteria isolated from quantitative tracheal aspirates in patients with VAP in this setting. Antimicrobial resistance was common across all bacterial species and we found a marked proportional annual increase in carbapenem-resistant Acinetobacter spp. over a 3 year period from 2008 (annual trend; odds ratio 1.656, P = 0.010). We further investigated the possible emergence of a carbapenem-resistant Acinetobacter baumannii clone by multiple-locus variable number tandem repeat analysis, finding a blaOXA-23-positive strain that was associated with an upsurge in the isolation of this pathogen. We additionally identified a single blaNDM-1-positive A. baumannii isolate. This work highlights the emergence of a carbapenem-resistant clone of A. baumannii and a worrying trend of antimicrobial resistance in the ICU of the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam.

Molecular epidemiology and antimicrobial resistance phenotypes of Acinetobacter baumannii isolated from patients in three hospitals in southern Vietnam

“…The predominance of ISAba1-bla OXA-23 in imipenem-nonsusceptible isolates in this study indicates the persistence and spread of [3]. The absence of isolates carrying bla OXA-24 gene in this study may be due to the small sample size; the prevalence of bla OXA-24 gene is low in Vietnam [13].…”

“…in Vietnamese patients during 2008-2011 [13]. The distribution of bla OXA genes and ISAba1 combinations and the corresponding imipenem resistance rates were not significantly different between the three hospitals.…”

“…This trend has been observed in Vietnam, and a significant increase in carbapenem-resistant On: Fri, 11 May 2018 09:21 :10 A. baumannii was observed in a sentinel Vietnamese infectious disease hospital over the last decade, with a rise in the number of MDR A. baumannii isolates harbouring bla OXA- 23 and bla OXA-51 [13]. Here we aimed to further consider the emergence of antimicrobial-resistant A. baumannii in Vietnam.…”

“…Extracted DNA from all organisms was diluted to a concentration of 25 ng µl À1 prior to PCR amplification using five specific primer pairs to detect the bla OXA-51 , bla OXA-23 , bla OXA-24 and bla OXA-58 (Table 1) Multiple-locus variable number tandem repeat analysis Multiple-locus variable number tandem repeat analysis (MLVA) (as previously described [20] with some modifications [13]) was used to genotype the 160 A. baumannii. Briefly, genomic DNA from each A. baumannii isolate was subjected to three multiplex PCR amplifications in a total volume of 10 µl, which included 2 µl DNA template, 1Â buffer enzyme, 1.…”

Carbapenem-Resistant Acinetobacter baumannii and Enterobacteriaceae in South and Southeast Asia

“…The results from recent reports (published from 2010) are summarized in Table 5. The prevalence of CRAB in Vietnamese hospitals is very high, ranging from 43% in a pediatric hospital in Ho Chi Minh City to 92% in a tertiary referral hospital in Hanoi (142)(143)(144)(145)(146)(147). Unfortunately, the bulk of the studies were based on ICUs, where carbapenem resistance rates are usually higher (142)(143)(144)147).…”