ABSTRACT
Objective To detect the distribution of resistance-nodulation (RND)efflux pump system of Acineto-bacter baumannii (AB),and explore the relationship between its’expression and antimicrobial resistance.Methods Fifty-nine strains of multidrug-resistant AB isolated from clinical specimens in The First Affiliated Hospital of Nan-chang University were identified and performed antimicrobial susceptibility analysis,distribution of RND efflux sys-tem of AB was detected by polymerase chain reaction(PCR),expression of efflux pump genes in different drug-re-sistant phenotypes of AB was compared,relationship between the expression level and drug resistance was analyzed, amplified products of RND efflux system were sequenced.Results Resistance rates of AB to ampicillin/sulbactam, imipenem,gentamicin,ciprofloxacin,and levofloxacin were 93.2%,94.9%,88.1%,96.6%,and 52.5% respec-tively.PCR detection results of efflux pump and integron genes of 59 AB strains revealed that the carrying rates of adeR,adeS,adeB,adeJ,and adeG genes were 81.4%,91.5%,93.2%,100.0%,and 61.0% respectively.The expression of efflux pump genes in different strains was different,expression levels of ade B and adeJ genes among gentamicin,imipenem,ampicillin/sulbactam resistant AB group and non-resistant AB group were significantly dif- ferent (all P＜0.05).There was no mutation or insertion sequence in the base sequences of regulatory genes ade R and ade S of adeABC efflux pump.Conclusion RND efflux pump system is universally present in AB,the expres-sion upregulation of ade B and ade J genes in RND efflux pump system is related with antimicrobial resistance of bacteria to gentamycin,imipenem,and ampicillin-sulbactam.
ABSTRACT
Objective To study the bactericidal efficacy of hospital commonly used disinfectants such as ethanol,3" chlorine tablets,iodophor,glutaraldehyde,and avagard instant hand antiseptic on Staphylococcus aureus (S.a ureus) from different sources of hospital,and provide scientific basis for effective control of healthcare-associated infection(HAI).Methods A total of 48 strains of S.aureus from inpatients,hands of health care workers,and environment surface in the First Affiliated Hospital of Nanchang University were collected.Disinfectant was directly contacted with bacteria,in vitro killing efficacy of disinfectant on S.aureus from different sources at different diluted concentrations,and different contact time were studied.Results The killing rate of 5g/L iodophor,20g/L glutaraldehyde,and avagard instant hand antiseptic(0.5％ chlorhexidine + 70％ ethanol) to S.aureus with a 5-minute contact time was 100％;killing rates of 70％ ethanol and 1g/L 3" chlorine tablets to S.aureus with a 5-minute contact time were 96.5 ％-99.8 ％;but highly diluted iodophor,glutaraldehyde,and avagard instant hand antiseptic still could not completely kill S.aureus even the contact time was extended.Conclusion The routine use of disinfectants in the hospital can meet the clinical bactericidal efficacy,it is necessary to monitor concentration routinely,avoid decreasing sterilization ability.