Nasal Carriage Prevalence, Antimicrobial Susceptibility Profiling And Molecular Characteristics Of Staphylococcus Aureus Among Part Of HIV-infected Population In Guangzhou

ObjectiveThe aim of this paper is to explore the carriage of Staphylococcus aureus(S.aureus)and Methicillin-resistant Staphylococcus aureus(MRSA)among HIV-infected persons,which is to study the influencing factors,antibiotic susceptibility and molecular characteristics of isolates.MethodsA cross-sectional study was conducted and convenience sampling mothers was perform to enrolled HIV-infected persons admitted to Guangzhou No.8 People’s Hospital.Epidemiologic information was obtained by selfdesigned questionnaire while nasal swabs were collected.The isolation of strain was carried out by using national standard method.Antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method.Multiplex PCR assay was used to identified the toxin gene and the staphylococcal cassette chromosome mec gene.Epidata3.1 was used for double logging data.Stata 13.0 was used for data processing.The univariate analysis of risk factors and the comparison of drug resistance rates was performed with chi-squared test or Fisher’s exact test.Non-conditional Logistic Regression models were used for multivariable analysis.ResultsDemographics:A total of 999 cases of HIV-infected persons were recruited for this study with an median age of 36.84.38% of them were male.80.49% of them were external population.The risk factors of S.aureus and MRSA carriage:Out of 999 study participants,with S.aureus carriage rate of 253(25.33%),of which 119 cases were MRSA(11.91%).In univariate analysis,age,marital status,and respiratory infection were statistically associated with S.aureus carriage(P<0.05);The results of multiple logistic showed that the heterosexual transmission was 3.846 times than the homosexuals transmission(OR=3.846,P=0.009).The participants with respiratory tract infection in a year were 1.530 times than uninfected(OR=1.530,P=0.029).In univariate analysis,age,aespiratory tract infection history and infection route were statistically associated with MRSA carriage(P<0.05).The results of multiple logistic suggested that the risk of male carried MRSA is 3.165 times than female.(OR=3.165,P=0.044).Risk of MRSA nasal carriage among heterosexual transmission was 3.413 times than homosexuals transmission(OR=3.413,P=0.045).The participants with respiratory tract infection were 2.044 times than uninfected(OR=2.044,P=0.010).The participants without receiving antiretroviral therapy were 2.133 times than the participants have received(OR=2.133,P=0.022).Antimicrobial susceptibility testing : Antibiotic resistance pattern results of S.aureus showed that the penicillin resistant rate was the highest(86.56%),the rate of clindamycin is lower than penicillin(39.92%),followed by teicoplanin(29.64%)and nitrofurantoin(29.64%);Drug resistance test results of MRSA showed that penicillin resistance was the highest(89.08%)as well,followed by erythromycin(61.34%),clindamycin(42.02%);MSSA has the highest resistant rate of penicillin(84.33%),followed by erythromycin(53.73%)and clindamycin(38.06%).Drug resistant rate of MRSA to cefoxitin,rifampicin,chloramphenicol,tetracycline and minocycline was higher than MSSA(P<0.05).The ratio of multidrug-resistant strains in MRSA was significantly higher than that in MSSA,and the difference was statistically significant(P<0.001).The risk factors of multidrug-resistant isolate carrying showed that the risk of respiratory tract infections within a year was 1.976 times than uninfected(OR=1.976,P=0.002).Molecular characteristics:The eta gene detection rate of S.aureus was 1.19%;the rate of pvl gene was 3.56%,the rate of tst gene was 2.34%,the rate of etb gene was 0.40%.There is no significant difference in the detection rate of pvl,eta,etb and tst genes between MRSA and MSSA(P>0.05).ConclusionThe carrying rate of S.aureus in Guangzhou among HIV-infected person is in the lower level of the worldwide,while the MRSA carrying situation is more serious.The male carriage rate is higher than female.The heterosexual transmission,antiretroviral therapy and respiratory tract infections within a year were the risk factors of S.aureus carriage.The multi drug resistance rate of S.aureus and MRSA were serious,which resisted teicoplanin.The proportion of multidrug-resistant isolates in MRSA was higher than MSSA.Respiratory tract infections within a year were the risk factors of the multi drug resistance.