ABSTRACT
Objective:To analyze drug resistance, virulence and molecular epidemiological characteristics of Staphylococcus aureus ( S. aureus) isolated from skin sites of suppurative infections, and to provide an experimental basis for clinical anti-infective therapies. Methods:Swab samples from suppurative skin lesions and nasal secretions were collected from inpatients in Department of Dermatology, the Affiliated Hospital of Inner Mongolia Medical University from May 2020 to December 2020, and subjected to bacterial isolation and culture. Suspected S. aureus colonies were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Drug sensitivity test was conducted by using the broth microdilution method. Virulence genes of S. aureus were amplified by PCR, and real-time fluorescence-based quantitative PCR was performed to determine the relative expression of 4 virulence genes including tsst-1, pvl, hla and clfA in S. aureus strains from different sources. S. aureus strains were genotyped by multilocus sequence typing. Drug resistance rates and detection rates of virulence genes were compared by using chi-square test or Fisher′s exact test, and measurement data among groups were compared by using t test or Mann-Whitney U test. Results:A total of 85 strains of S. aureus were isolated from 210 inpatients, including 54 isolates from skin sites of suppurative infections (case group) and 31 isolates from the nasal cavity (control group) . Drug sensitivity test showed that 14 strains of methicillin-resistant S. aureus (MRSA) were identified among 85 strains of S. aureus. The resistance rate to penicillin was the highest (90.59%, 77/85) in the 85 S. aureus strains; the resistance rates to clindamycin and erythromycin were 60.00% (51/85) and 61.18% (52/85) respectively; no strains showed resistance to rifampicin, vancomycin or linezolid. PCR showed that the detection rate of the pvl gene was 33.33% (18/54) in the case group, which was significantly higher than that in the control group (12.90%, 4/31; χ2= 4.28, P= 0.038) . Real-time fluorescence-based quantitative PCR showed that the relative expression level of the clfA gene was significantly higher in the control group (3.87[2.30, 5.94]) than in the case group (1.63[0.95, 2.62], P= 0.007) . A total of 17 ST types were identified among the 85 strains of S. aureus, and the dominant types were ST398-methicillin-susceptible S. aureus (20/71) and ST22-MRSA (9/14) . The detection rate of the virulence gene pvl was significantly higher in the ST22-MRSA strain (14/14) than in the non-ST22 MRSA strains (0, P < 0.001) . Conclusions:S. aureus strains isolated from the skin sites of suppurative infections were highly resistant to penicillin, clindamycin and erythromycin, so these antibiotics should not be used as the first-choice empiric treatment. The occurrence of cutaneous S. aureus infections may be associated with the virulence gene pvl, and the nasal colonization of S. aureus may be associated with the clfA gene.
ABSTRACT
Objective To investigate the clinical efficacy of adefovir dipivoxil in antiviral treatment of chronic hepatitis B and its effect on peripheral blood T lymphocyte subsets.Methods 40 cases of patients with chronic hepatitis B were selected from The Fourth People’s Hospital of Qinghai in October 2009 to June 2012,the patients were given the antiviral treatment of adefovir dipivoxil.Before treatment,3 months,6 months and 12 months after treatment,the changes of liver function indicators of alanine transaminase(ALT),aspartate transaminase(AST)and total bilirubin(TBiL),and hepatitis B virus-DNA(HBV-DNA)were recorded;the total effective rate was observed;the peripheral blood T lymphocyte subsets changes was tested and analyzed by flow cytometry.Results The ALT,AST and TBiL of the patients all improved good,and the indicators of ALT,AST and TBiL after 12 months decreased significantly than before treatment,the HBV-DNA testing of the patients recovered negative,the difference was statistically significant (P<0.05 );the total effective rate of hepatitis B patients is 92.5%;the peripheral blood T lymphocyte subsets has no significant improvement in patients after antiviral treatment for 3 months.After the treatment for 6 months and 12 months,the CD4 +T and CD4 +/CD8 +T were significantly higher than those before treatment,there was no significant changes in CD3 +T and CD8 +T before and after treatment.Conclusion Adefovir dipivoxil has a good clinical efficacy in antiviral treatment of chronic hepatitis B,and can significantly improve the patients’liver function,improve peripheral blood T lymphocyte subsets imbalance.