The drug resistance characteristics and multilocus sequence typing of carbapenem-resistant Pseudomonas aeruginosa
Objective To investigate the clinical distribution and genetic phenotypes of carbapenem-resistant Pseudomonas aerugino-sa(CRPA),and provide basis for clinical rational drug use and nosocomial infection control.Methods Sixty strains of non-repeated carbapenem-resistant aeruginosa isolated clinically from July 2021 to June 2022 were collected from The First Affiliated Hospital of He'nan University of Chinese Medicine for identification and drug sensitivity testing,and the clinical distribution and source of speci-mens were analyzed.Thirty five CRPA strains were randomly selected,and the seven housekeeping genes acsA,aroE,guaA,mutL,nu-oD,ppsA and trpE of Pseudomonas aeruginosa were amplified using the multi-locus sequence typing method(MLST),and the PCR am-plification and sequencing were used to analyze the genetic variability of the isolated CRPAs using software such as DNAstar and PHY-LOViZ 2.0.Results Sixty CRPA strains were mainly isolated from the respiratory department,rehabilitation department,and ICU,the main type of specimen was sputum(63.3%).The resistance rates to antibiotics were more above 40%,except polymyxin,amikacin and gentamicin.Compared with carbapenem-susceptible Pseudomonas aeruginosa(CSPA)isolated during the same period,the CRPA strains had significantly higher resistance rates to antibiotics such as amikacin(23.3%),cefepime(58.3%),ceftazidime(48.3%),cipro-floxacin(55.0%),piperacillin/tazobactam(45.0%),aztreonam(56.7%),and meropenem(78.3%),except polymyxin,and the difference was statistically significant(P<0.05).MLST analysis showed that 35 CRPA strains belonged to 25 different ST types,of which the domi-nant STs was ST1182.In this study,a new allele trpE316,three new ST phenotypes,ST3978,ST3979 and ST3980 were identified.Conclusions Respiratory tract infection is the main cause of CRPA in this study,which is more common in the respiratory depart-ment.The CRPA resistance situation is serious,and targeted interventions should be taken in conjunction with drug sensitivity results and epidemiological analysis.The results of MLST analysis show the existence of diversified ST types and clone types,suggesting that the genetic background of these strains is also complex and variable.
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