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

Abstract

Acinetobacter baumannii is a leading pathogen responsible for nosocomial infections. The emergence of carbapenem-resistant A. baumannii (CRAB) has left few effective antibiotics for clinicians to use. To investigate the temporal evolutionary relationships among CRAB strains, we collected 248 CRAB isolates from a Chinese burns institute over 3 years. The prevalence of the OXA-23 gene was detected by polymerase chain reaction. Multilocus sequence typing was used to type the CRAB strains and eBURST was used to analyze their evolutionary relationships. Wound surfaces (41%), sputa (24%), catheters (15%), and bloods (14%) were the four dominant isolation sources. Except for minocycline (33.5%) and sulbactam/cefoperazone (74.6%), these CRAB strains showed high resistance rates (>90%) to 16 tested antibiotics. The 248 isolates fall into 26 sequence types (STs), including nine known STs and 17 unknown STs. The majority (230/248) of these isolates belong to clonal complex 92 (CC92), including eight isolates belonging to seven unreported STs. A new CC containing 11 isolates grouped into four new STs was identified. The OXA-23 gene was detected at high prevalence among the CRAB isolates and the prevalence rate among the various STs differed. The majority of the isolates displayed a close evolutionary relationship, suggesting that serious nosocomial spreading and nosocomial infections of CRAB have occurred in the burn unit. In conclusion, the main CC for CRAB in this Chinese burn unit remained unchanged during the 3-year study period, and a new CC was identified. CC92 was the dominant complex, and more attention should be directed toward monitoring the new CC we have identified herein.

Characterization and genome annotation of a newly detected bacteriophage infecting multidrug-resistant Acinetobacter baumannii

“…It is among the leading causes of infections of the respiratory and urinary tracts, secondary meningitis, and sepsis [ 2 ]. Some strains of this widespread Gram-negative pathogen have been reported recently to be resistant to nearly all known antibiotics, and there is therefore an urgent need to find alternative treatments for these infections [ 3 , 4 ].…”

A 5-year Survey Reveals Increased Susceptibility to Glycopeptides for Methicillin-Resistant Staphylococcus aureus Isolates from Staphylococcus aureus Bacteremia Patients in a Chinese Burn Center

“…This result was similar to burn survey reports by Song et al (98%) from Korea (Song et al, 2001 ), Khosravi et al (87.4%), and Parhizgari et al (86.4%) from Iran (Khosravi et al, 2012 ; Parhizgari et al, 2016 ), but higher than that reported by Chen et al (55.3%) from southeast China (Chen et al, 2012 ). In contrast to the molecular typing results of other common bacteria from burn patients, such as Acinetobacter baumannii and Pseudomonas aeruginosa , which often display diverse molecular types (Huang et al, 2016 ; de Almeida Silva et al, 2017 ), the molecular types of S. aureus in burn wards were typically simple according to previous studies (Chen et al, 2012 ; Parhizgari et al, 2016 ). In our center, almost all the MRSA strains carried SCCmec III (96.23%), which is a characteristic of nosocomial MRSA strains and is associated with the capacity to resist antimicrobials (Cheng et al, 2013 ).…”

Molecular Characterization and Antibiotic Resistance of Acinetobacter baumannii in Cerebrospinal Fluid and Blood

“…ST540, ST195 and ST208 were three major STs for A. baumannii isolated from CSF and blood. Among them, ST195 and ST208 are two dominant STs currently found in China [32][33][34]. Although ST540 was not the main ST observed in China, it was shown that ST540 was not only one of the three common STs but also the predicted founder of the CC for A. baumannii isolated from blood and CSF.…”