ABSTRACT
Objective To investigate the molecular types and related clinical features of methicillin-resistant Staphylococcus aureus (MRSA) in Jingzhou area, Hubei Province.Methods A total of 80 MRSA strains confirmed by mecA gene were isolated from inpatients in Jingzhou Central Hospital of Hubei province during January and December 2014. Vitek 2 Compact was used for antibiotic susceptibility test . Staphylococcus protein A (SPA) types and Staphylococcal cassette chromosome mec (SCCmec) genotypes were detected by multiplex polymerase chain reaction ( PCR ) and gene sequencing . Panton-valentine leucocidin ( pvl) gene of the strains was detected by PCR .Chi-square test and Wilcoxon test were used for data analysis .Results There were 16 spa types in 80 MRSA isolates , in which t030 and t437 were the most prevalent ones accounting for 50.0% ( 40 strains ) and 28.8% ( 23 strains ) of the total strains, respectively.There were 77 strains of SCCmec type Ⅰ-Ⅴ, in which SCCmecⅢ and SCCmecⅣ were the most prevalent ones accounting for 45.0% (36 strains) and 35.0% (28 strains), respectively.t030 was the main spa type in isolates of SCCmecⅢ(33/36, 91.7%), while t437 was the main spa type in isolates of SCCmecⅣ(20/28, 71.4%).Patients infected with t030/SCCmecⅢMRSAs were with higher ages than those infected with t437/SCCmecⅣMRSAs (T=446.500 and 607.500, P<0.01).Patients infected with t030/SCCmecⅢ MRSAs were mainly from surgical wards and intensive care unit ( ICU ) , while those infected with t437/SCCmecⅣ MRSAs were mainly from pediatrics wards , and there were significant differences in ward distribution between two groups (χ2 =33.724 and 29.768, P <0.01).Seventy percent and above strains of t030/SCCmec type Ⅲ were resistant to rifampin, erythromycin, clindamycin, tetracycline, levofloxacin, moxifloxacin, ciprofloxacin and gentamicin .Strains of t437/SCCmec type Ⅳwere resistant to erythromycin , clindamycin and tetracycline , but were sensitive to most non-β-lactam antimicrobial drugs (with resistance rates <20%).Virulence gene pvl was found in 11 strains (13.8%), in which 7 were strains of t437-SCCmec typeⅣ.Conclusions MRSAs in Jinzhou are of various genotypes , in which t030-SCCmecⅢand t437-SCCmecⅣare the most prevalent ones .Strains of t030-SCCmec typeⅢare usually multiple-drug resistant , mainly seen in elderly patients in surgical wards and ICU .Strains of t437-SCCmecⅣare sensitive to most non-β-lactam antimicrobial drugs , and its infection is mainly seen in children and young people .
ABSTRACT
Objective To investigate the correlation between expression of Panton-Valentine leukocidin gene and accessory gene regulator among different clinical isolates of Staphylococcus aureus.Methods All non-duplicate Staphylococcus aureus clinical isolates were isolated from various clinical specimens of the patients at 4 hospitals from January 2003 to December 2010.Panton-Valentine leukocidin genes among Staphylococcus aureus clinical isolates were detected by PCR and DNA sequencing.The expressions of lukS-PV and agrA were determined by real-time PCR.Results Ninty-six S.aureus isolates including 58 hospital-acquired and 28 community-acquired isolates were positive for PVL genes,among which 54 from blood,33 from pus and 9 from sputum.Ten isolates cannot be classified due to lack of information.Sixty-seven and 29 PVL-positive isolates were isolated from the specimens of adults and children.The median relative quantities of lukSmRNA of the isolates from pus and blood were 1.500 and 0.818.The quantity of lukSmRNA among the isolates from pus was significantly higher than that from blood (U =634,P =0.025).The median relative quantities of lukSmRNA of the isolates from children and adults were 1.292 and 0.540,respectively.The quantity of lukSmRNA among the isolates from children was significantly higher than that from adults (U =660,P =0.013).The median relative quantities of lukSmRNA among community-acquired and hospital-acquired isolates were 1.034 and 0.536,respectively.The quantity of lukSmRNA among community-acquired isolates was significantly higher than that from hospital-acquired isolates (U =338,P =0.012).The correlation coefficients between lukSmRNA and agrAmRNA of total isolates,pus isolates and blood isolates were 0.592 (P ＜ 0.01),0.810 (P ＜ 0.0l) and 0.543 (P ＜0.01),respectively.While the correlation coefficients of those among the isolates from children and adults were 0.804 (P ＜ 0.01) and 0.476 (P ＜ 0.01).The correlation coefficients of those among the isolates from community-acquired and hospital-acquired isolates were 0.767 (P ＜ 0.01) and 0.556 (P＜0.01).Conclusions The quantity of lukSmRNA of Staphylococcus aureus isolates from pus was significantly higher than that from blood.The agr may have positive regulation effect on the expression of lukS/F-PV,especially among the isolates from pus and children.(Chin J Lab Med,2013,36:313-317)
ABSTRACT
Community acquired infections with methicillin resistant strains of Staphylococcus aureus (MRSA) infections have a more aggresive clinical course and involve mostly skin and lungs. These infections appear as outbreaks among prisoners, sportsmen, men having sex with men and military personnel. The higher aggressiveness of these strains is due to the production of several toxins, mainly Panton- Valentine leukocidine. The detection of the gene that codes for this toxin is a distinctive feature of these strains. We report five patients with community acquired MRSA infections. The clinical presentation was a skin infection in all. One patient had a pleuropneumonia in addition. Apart for resistance to beta-lactam antimicrobials, the strains were resistant to erythromycin and ciprofloxacin. Patients were treated with vancomycin, clotrimoxazole or intravenous clindamycin with a good evolution. An epidemiológical surveillance for community acquired MRSA strain infections should be started and measures to adequately treat infected patients and avoid dissemination should be implemented.
Subject(s)
Adolescent , Adult , Female , Humans , Male , Young Adult , Methicillin Resistance , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Staphylococcal Skin Infections/microbiology , Anti-Bacterial Agents/therapeutic use , Chile , Community-Acquired Infections/diagnosis , Community-Acquired Infections/drug therapy , Community-Acquired Infections/microbiology , Methicillin Resistance/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Polymerase Chain Reaction , Staphylococcal Skin Infections/drug therapy , Travel , Young AdultABSTRACT
Objective To investigate the infections caused by Staphylococcus aureus carrying Panton-Valentine leukocidin(PVL)genes.Methods 26 isolates of Staphylococcus aureus carrying Panton- Valentine leukocidin(PVL)genes were determined by multiplex PCR.Multilocus sequence typing(MLST) was used to determine the STs of the isolates.The genotypes of SCCmec were also determined by another multiplex PCR in the isolates of methicillin-resistant Staphylococcus aureus(MRSA).Results Among 26 isolates,there were 6 isolates of ST88 MRSA,7 isolates of ST88 methicillin-susceptible Staphylococcus aureus (MSSA),5 isolates of ST239 MRSA,5 isolates of ST398 MRSA,1 isolate of ST25 MRSA,1 isolate of ST30 MRSA and 1 isolate of ST59 MRSA.20 isolates were hospital-acquired(HA)which mainly caused pulmonary infection and post-operative pyogenic infection.6 isolates were community-acquired(CA)which mainly caused soft tissue necrosis.Among 19 isolates of MRSA,ST88-SCCmec Ⅲ A,ST239-SCCmec Ⅲ,ST398- SCCmec Ⅳ and ST398-SCCmec Ⅲ were main types.26 isolates were isolated from 14 wards.ST88-SCCmec Ⅲ A-MRSA caused clone spread in maternity department in our hospital.Conclusion ST88,ST239 and ST 398 are main STs in Staphylococcus aureus carrying PVL in our hospital.The isolates not only cause nosocomial infections but also cause community infection.