Background To investigate the carbapenem resistance mechanisms and clonal relationship of carbapenem-resistant Acinetobacter baumannii (CRAB) strains isolated in the intensive care unit (ICU) of the First Affiliated Hospital of Jiamusi University, management approaches to ICU clonal CRAB outbreaks were described. Methods The sensitivity of the antibiotic was determined using the VITEK-2 automated system. Carbapenemase genes ( bla TEM , bla SHV , bla KPC , bla NDM , bla IMP-4 , bla VIM , bla OXA-23 , bla OXA-24 , bla OXA-51 , and bla OXA-58 ), AmpC enzyme genes ( bla ACC , bla DHA , bla ADC ), and ISAba1 were assessed for all collected isolates using polymerase chain reaction (PCR). The transfer of resistance genes was investigated via conjugation experiments. The clonal relationship of isolates was determined via enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus sequence typing (MLST). When the detection rate of CRAB increased from 25% in 2010 to 92% in 2014, a number of actions were initiated, including enhanced infection control, staff education, and the cleaning of the hospital environment. Results Clinical isolates were positive for the following genes: bla OXA23 , bla OXA51 , bla OXA24 , bla ADC , bla TEM , ISAba1 , ISA-23 , and ISA-ADC ; however, bla OXA58 , ISA-51 , bla NDM , bla IMP , bla KPC , bla TEM , bla SHV , bla VIM , and bla ACC were not detected. Four carbapenem-resistant isolates successfully transferred plasmids from A. baumannii isolates to E. coli J53. MLST showed that all strains belonged to ST2 except for one isolate, which belonged to the new genotype ST1199. The ERIC-PCR method fou...

BackgroundDue to the critical condition and poor immunity of patients, the intensive care unit (ICU) has always been the main hospital source of multidrug-resistant bacteria. In recent years, with the large-scale use of antibiotics, the detection rate and mortality of carbapenem-resistant Klebsiella pneumoniae (CRKP) have gradually increased. This study explores the molecular characteristics and prevalence of CRKP isolated from the ICU ward of a tertiary hospital in China.MethodsA total of 51 non-duplicated CRKP samples isolated from the ICU were collected from July 2018–July 2020. The enzyme production of the strains was preliminarily screened by carbapenemase phenotypic test, and drug-resistant and virulence genes were detected by PCR. The transferability of plasmid was verified by conjugation test. The minimal inhibitory concentration (MIC) was determined by microbroth dilution method and genetic diversity was detected by multilocus sequence typing and pulsed-field gel electrophoresis.ResultsblaKPC-2 was the only carbapenemase detected. The major virulence genes were uge (100%), mrkD (94.1%), kpn (94.1%), and fim-H (72.5%), while wcag, ironB, alls and magA genes were not detected. One sequence type ST1373 strain, hypervirulent K. pneumoniae (hvKP), was detected. CRKP strains were highly resistant to quinolones, cephalosporins, aminoglycosides, and polymyxin, but susceptive to tigecycline and ceftazidime–avibactam. The success rate of conjugation was 12.2%, indicating the horizontal transfer of blaKPC-2. Homology analysis showed that there was a clonal transmission of ST11 CRKP in the ICU of our hospital.ConclusionThe present study showed the outbreak and dissemination in ICU were caused by ST11 CRKP, which were KPC-2 producers, and simultaneously, also carried some virulence genes. ST11 CRKP persisted in the ward for a long time and spread among different areas. Due to the widespread dispersal of the transferable blaKPC-2 plasmid, the hospital should promptly adopt effective surveillance and strict infection control strategies to prevent the further spread of CRKP. Ceftazidime–avibactam showed high effectiveness against CRKP and could be used for the treatment of ICU infections.