Genetic Characterization of ST195 and ST365 Carbapenem-Resistant Acinetobacter baumannii Harboring bla_OXA-23 in Guangzhou, China

Abstract

We investigated the distribution of resistance genes and the clonal relationships among carbapenem-resistant Acinetobacter baumannii isolates from the intensive care unit wards of two hospitals in Guangzhou, China. From 2012 to 2013, 57 A. baumannii isolates were obtained from blood cultures from two hospitals in Guangzhou. The antibiotic resistance profiles were determined by using the Vitek2 system and Etest strips. PCR was used to detect the genes encoding OXA-type carbapenemases and metallo-β-lactamases and the presence of ISAba1 upstream of the bla(OXA-51-like) gene and the bla(OXA-23-like) gene. Multilocus sequence typing (MLST) and sequence-based typing of bla(OXA-51-like) genes (SBT-bla(OXA-51-like )genes) were performed to analyze the genetic relationship of the isolates. Among the 57 isolates, 46 were carbapenem-resistant A. baumannii (CRAB) isolates. The bla(OXA-51-like) gene was identified in all 57 isolates, while the bla(OXA-23-like) gene was present in all 46 CRAB isolates. The MLST analysis grouped the A. baumannii isolates into five existing sequence types (STs) and five new STs. Fifty-two isolates belonged to the worldwide spread of clonal complex 92 (CC92), among which ST195 and ST365 were the most common STs. The MLST data and SBT-bla(OXA-51-like) genes showed that all isolates harboring the major bla(OXA-51-like) alleles, such as bla(OXA-66), belonged to CC92.

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

“…In this study, ST195 was the most commonly observed ST, accounting for 24/52 (46.1%) of the isolates, follow by ST208. These Values are presented as the mean ± standard deviation; malignancy includes haematological malignancies and solid tumours; cardiac disease includes coronary artery disease, hypertensive heart disease, valvular disease and cardiomyopathy; renal disease includes chronic renal failure; neurological disease includes cerebral haemorrhage and cerebral infarction; PPIs proton pump inhibitor drugs findings are similar to the findings of Zhou et al [25], who found that ST195 accounted for 31/57 (54.4%) isolates. These data collectively suggest that ST195 is the most common ST and may serve as a severe epidemic marker in the Guangzhou area.…”

“…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.…”

Active efflux pump adeB is involved in multidrug resistance of Acinetobacter baumannii induced by antibacterial agents

“…Moreover, a significantly increased positive rate was observed in the β-lactamase gene in strains subjected to drug induction, particularly OXA-23 (64.9%) and AmpC (91.9%). To our knowledge, OXA-23-producing A. baumannii was resistant to IPM (29)(30)(31)(32)(33)(34)(35)(36). AmpC enzyme was encoded by chromogene, and it's over expression could induce drug resistance towards penicillin and the third generation broad-spectrum cephalosporins, through hydrolysis.…”

Multilocus Sequence Typing Analysis of Carbapenem-Resistant Acinetobacter baumannii in a Chinese Burns Institute

“…All known STs have been reported in China, where ST92 was the main ST before 2010 (Ruan et al, 2013), and ST195 together with ST208 are currently the main STs (Zhou et al, 2015; Qu et al, 2016). In the present study, ST195 and ST208 were moderately common STs and ST368 was the dominant type.…”

“…In fact, the OXA-23 carriage rate in China is relatively high. Some investigations have shown that the prevalence reached over 90% in coastal areas (Ji et al, 2014; Zhou et al, 2015). Additionally, the prevalence of the OXA-23 gene varies among isolates with different STs.…”