Molecular Epidemiology and Characterization of Genotypes of <i>Acinetobacter baumannii</i> Isolates from Regions of South China

Abstract

SUMMARY:The aim of this study was to analyze the molecular epidemiologic characteristics of Acinetobacter baumannii. A total of 398 isolates were collected in 7 regions of South China from January to June of 2012. Drug sensitivity was tested toward 15 commonly used antibiotics; thus, 146 multidrug-resistant strains (resistant to more than 7 drugs) were identified, representing 36.7z of all isolates. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used for molecular subtyping. According to the PFGE results (with a cutoff of 70z similarity for the DNA electrophoretic bands), 146 strains were subdivided into 15 clusters, with cluster A being the largest (33.6z, distributed in all districts except Jiaxing). Cluster B was also widespread and included 14.4z of all strains. In addition, MLST results revealed 11 sequence types (ST), with ST208 being the most prevalent, followed by ST191 and ST729. Furthermore, 4 novel alleles and 6 novel STs were identified. Our results showed that multi-drug-resistant A. baumannii in South China shares the origin with other widespread strains in other countries. The nosocomial infections caused by A. baumannii have been severe in South China. Continuous monitoring and judicious antibiotic use are required.

Pneumonia caused by extensive drug-resistant Acinetobacter baumannii among hospitalized patients: genetic relationships, risk factors and mortality

“…However, ST92, which was the predicted founder of CC92 and was reported to be one of the most epidemic STs in multiple provinces in China [1, 10, 11], was not detected in our study. ST92 was also not detected in other studies from China [1, 5] and South Africa [24]. The lack of ST92 detection may be due to the relatively small sample size in our study, which may not accurately represent the diversity and relative abundance of A. baumannii STs.…”

“…The most common bodily site of A. baumannii infection is the respiratory tract, particularly in cases of hospital-acquired pneumonia (HAP) [1, 2]. A. baumannii is also notorious for its remarkable ability to acquire antibiotic resistance.…”

Pneumonia caused by extensive drug-resistant Acinetobacter baumannii among hospitalized patients: genetic relationships, risk factors and mortality

“…However, ST92, which was the predicted founder of CC92 and was reported to be one of the most epidemic STs in multiple provinces in China [1,10,11], was not detected in our study. ST92 was also not detected in other studies from China [1,5] and South Africa [24]. The lack of ST92 detection may be due to the relatively small sample size in our study, which may not accurately represent the diversity and relative abundance of A. baumannii STs.…”

“…The lack of ST92 detection may be due to the relatively small sample size in our study, which may not accurately represent the diversity and relative abundance of A. baumannii STs. However, some studies [1,5,25] have shown that ST195, ST208, ST365, and ST191 (but not ST92) are the most common STs discovered in different hospitals across China. In this study, ST195 was the most commonly observed ST, accounting for 24/52 (46.1%) of the isolates, follow by ST208.…”

iTRAQ-Based Differential Proteomic Analysis Reveals the Pathways Associated with Tigecycline Resistance in Acinetobacter baumannii

“…As a class of glycylcyclines, tigecycline is modified by a 9-t-butyl-glycylamido side chain on the minocycline, by which the drug can bind to the ribosomes of bacterial pathogen with high affinity. This characteristic makes it possible that tigecycline retain susceptibility to a broad range of bacteria, including the Gram-positive and Gram-negative, and get out of the major resistance mechanisms of pathogen [21]. However, tigecycline resistance has increasingly emerged [22,23].…”