Sequence Type 191 of Clonal Complex 92 was a Dominant Carbapenem-Resistant Acinetobacter Baumannii that Causes Nosocomial Pneumonia in Intensive Care Units in a Teaching Hospital in Central China

Background: The aim of our study was to investigate the carbapenem-resistant blaOXA genotype distribution and multilocus sequence typing (MLST) sequence types (STs) of Acinetobacter baumannii that cause nosocomial pneumonia in the intensive care unit (ICU) of a teaching hospital in central China. Methods: Forty-two non-repeated A. baumannii isolates were collected from airways of ICU patients who were diagnosed with nosocomial pneumonia. The genetic relationship was investigated using repetitive extragenic palindromic-polymerase chain reaction (rep-PCR) and MLST. Bla(OXA) carbapenem-resistant genes were analyzed by multiplex PCR. Results: The A. baumannii strains were divided into three genotypes by rep-PCR. The prominent cluster was labeled A and consisted of sequence type 191 (ST191) as the main sequence type, which accounted for 90.5% (38/42) of isolates in the hospital. Drug-susceptibility testing showed that 81% (34/42) of the 42 isolates were resistant to carbapenem. The bla(OXA-51-like) gene was detected in all clusters and most of the A. baumannii strains contained bla(OXA-23-like) + bla(OXA-51-like) gene resistance to imipenen and meropenem. Patients infected with ST191 had a higher rate of carbapenem antibiotic use within the last 3 months. Conclusions: The strain with ST191 may become the new predominant A. baumannii strain in China.