Study On Prevalence,Phenotypic And Genetic Characteristics In Methicillin-Resistant Coagulase-Negative Staphylococci From Nasal Carriage By HIV-positive Patients

ObjectiveTo investigate the prevalence,factors,antibiotic resistance,and genetic characteristics of methicillin-resistant coagulase-negative staphylococci(MRCoNS)from nasal carriage by HIV-positive patients.MethodsWe conducted a cross-sectional study and investigated the prevalence of MRCoNS from nasal carriage by HIV-positive patients in outpatient department in Guangzhou eighth municipal people's hospital,with convenience sampling.All subjects were recruited as voluntaries after they signed an informed consent form.Coagulase-negative staphylococci were isolated and identified using a series of conventional laboratory methods.Formal antimicrobial susceptibility testing was performed on all coagulase-negative staphylococci isolates by the Kirby-Bauer disk diffusion method of Clinical and Laboratory Standards Institute guidelines.All coagulase-negative staphylococci isolates were tested to confirm the presence of genes including 16 S rRNA,nuc,mecA,mecC,resistance genes,toxin gene and antiseptic-resistance genes gene using polymerase chain reaction.Prevalence rate was used to describe the prevalence of MRCoNS from nasal carriage by HIV-positive patients and rates were used to describe the proportions of resistance and genes.Univariate analysis was using Pearson's chi-squared test or Fisher's exact test.Logistic models were constructed to multivariable analysis using the variables if P<0.05 in univariate analysis.Logistic analysis,Pearson's chi-squared test or Fisher's exact test were used to compare the rates of drug resistance and genes between MRCoNS and methicillin-susceptible coagulase-negative staphylococci(MSCoNS)Data analysis was performed using Stata 13.0 software.ResultsThe prevalence of MRCoNS nasal carriage by HIV-positive patients: The prevalence of coagulase-negative staphylococci,MRCoNS,methicillin-resistant S.epidermidis(MRSE),methicillin-resistant S.haemolyticus(MRSH)and multi-drug resistant methicillin-resistant coagulase-negative staphylococci(MDRMRCoNS)carriage was 57.44%(575/1001),42.26%(423/1001),30.87%(309/1001),9.99%(100/1001)and 34.27%(343/1001),respectively.The influencing factors of MRCoNS nasal carriage by HIV-positive patients: The risk of MRCoNS nasal carriage among HIV-positive patients with college degree or above was lower.Last 6 months,taking trimethoprim-sulfamethoxazole or other prophylactic antibiotics increased the risk of MRCoNS nasal carriage among HIV-positive patients.The risk of MDRMRCoNS nasal carriage among HIV-positive patients with college degree or above was lower.Had having operation in nearly a year,taking trimethoprim-sulfamethoxazole or other prophylactic antibiotics last 6 months and most recent CD4/CD8 ratio<0.2 increased the risk of MDRMRCoNS nasal carriage among HIV-positive patients.The numbers of cohabitation>3,exposure to domestic rats or their secretions and taking trimethoprim-sulfamethoxazole or other preventive antibiotics last 6 months increased the risk of MRSE nasal carriage among HIV-positive patients.Sharing bath towels with others can reduce the risk of carrying MRSE among HIV-positive patients.Sharing household supplies with others increased the risk of MRSH among HIV-positive patients.The risk of MRSH nasal carriage among HIV-positive patients with Guangzhou resident was lower.Antimicrobial resistance: In this study,the proportions of resistance to penicillin(93.71%),erythromycin(72.89%)and trimethoprim-sulfamethoxazole(54.23%)of MRCoNS were higher in HIV-positive patients.Compared with methicillin-susceptible coagulase-negative staphylococci,MRCoNS isolates increased the risk of resistance to penicillin,erythromycin,trimethoprim-sulfamethoxazole,mosifloxacin,tetracycline,clindamycin and rifampicin.Compared with non-MDRMRCoNS,MDRMRCoNS increase the risk of resistance to 11 classes of antibiotics.The proportions of resistance to penicillin(94.17%),erythromycin(68.61%)and trimethoprim-sulfamethoxazole(60.19%)of MRSE were higher in HIV-positive patients.Compared with methicillin-susceptible S.epidermidis,MRSE isolates increased the risk of resistance to penicillin,erythromycin,trimethoprim-sulfamethoxazole,tetracycline and mercifloxacin.The proportions of resistance to penicillin(94.00%),erythromycin(87.00%),gentamicin(77.00%),mercifloxacin(67.00%)and clindamycin(50.00%)of MRSH were higher in HIV-positive pateins.Compared with methicillin-susceptible S.haemolyticus,MRSE increased the risk of resistance to penicillin,erythromycin and moxifloxacin.The multiple resistance rates of MRCoNS and MRSE were over 79%,and that of MRSH were over 95%.Molecular characteristic: In this study,the most predominant resistance genes of MRCoNS were aac(6')-aph(2')(66.16%),tet(K)(48.16%)and erm(C)(55.97%)among HIV-positive patients,and these resistance genes detectable rates of MRCoNS isolates were higher than that of MSCoNS(P<0.05).The most predominant resistance genes in MDRMRCoNS were aac(6')-aph(2')(69.35%),tet(K)(52.15%),erm(C)(58.87%)and lin(A)(51.61%)among HIV-positive patients,and these resistance genes detectable rates of MDRMRCoNS isolates were higher than that of non-MDRMRCoNS(P<0.05).The most predominant resistance genes in MRSE were aac(6')-aph(2')(63.75%),tet(K)(46.60%)and erm(C)(54.69%)among HIV-positive patients,and these resistance genes detectable rates of MRSE isolates were higher than that of MRSH(P<0.05).The most predominant resistance genes in MRSH were aac(6')-aph(2')(74.00%),tet(K)(52.00%),erm(C)(60.00%)and lin(A)(35.00%)among HIV-positive patients in this study.The detectable rates of pvl gene of MRCoNS,MRSE and MRSH were 3.45%,6.72%,9.06% and 2.0%,respectively.The predominant antiseptic-resistance genes was qacA/B among MRCoNS,MDRMRCoNS,MRSE and MRSH isolates,and rates of MRCoNS,MDRMRCoNS,MRSE and MRSH isolates were 52.71%,56.99%,53.72% and 58.00%,respectively.ConclusionsThe prevalence of MRCoNS carriage was high,and MRSE and MRSH were mainly detected.Taking trimethoprim-sulfamethoxazole or other prophylactic antibiotics for last 6 months was the risk factor MRCoNS nasal carriage among HIV-positive patients.Had having antibiotic drugs and operation in nearly a year,taking trimethoprim-sulfamethoxazole or other prophylactic antibiotics last 6 months and most recent CD4/CD8 ratio<0.2 were the risk factor MDRMRCoNS nasal carriage among HIV-positive patients.The numbers of cohabitation>3,exposure to domestic rats or their secretions and taking trimethoprim-sulfamethoxazole or other preventive antibiotics last 6 months were the risk factor MRSE nasal carriage among HIV-positive patients.Sharing household supplies with others was the risk factor MRSH nasal carriage among HIV-positive patients.Multi-drug resistance of MRCoNS nasal carriage among HIV-positive patients was serious,especially MRSH.The genes of aac(6')-aph(2'),tet(K),erm(C),lin(A)and qacA/B were predominant detected in MRCoNS,MRSE and MRSH isolates among HIV-positive patients.