| ObjectivesStaphylococcus aureus is a common infection of pathogens, Staphylococcusaureus (SAU) and Staphylococcus epidermidis (SEP) is the main Staphylococcusbacteria, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistantStaphylococcus epidermidis (MRSE) infection are increased, they has become themain hospital infection pathogens. Especially the gradually increased ofmethicillin-resistant Staphylococcus epidermidis (MRSE) caused all sorts of difficultiesin clinical treatment. In order to control the infection of staph, the assay of themethicillin-resistant in clinical studied the resistance of methicillin-resistant andexplored the risk factors, it is a guide to use of antibiotics in clinical treatment, andtakes measure to reduce these resistant bacteria in hospitals as a basis.Materials and methodsFrom October 2002 to October 2006, 189 isolates of Staphylococcus epidermidisidentified by the antimicrobial laboratory in China Medical University were collected.Isolates wee collected from the patients' sputum, urine, blood, wound exudates,prostate fluid, ascites, and intraductal and cerebrospinal fluid specimens, 124 of whichwere MRSE, the number of MSSE is 65, the prevalence rate of MRSE is 65.6%.In accordance with the rules of the clinical test, Staphylococcus is identified tospecies. And then we use the method of K-B to measure the Reuse Determination≥25mm, according to NCCLS standards for methicillin-resistant is Staphylococcusaureus. We measure ampicillin, gentamicin, chloramphenicol, clindamycin, tetracycline,rifampicin, erythromycin, penicillin, Vancomycin, levofloxacin, Rifampin Oxacillin,Teicoplanin, Trimethoprim-sulfamethoxazole by mean of K-B method. Bacteriasusceptibility to 15 antimicrobial agents was determinded according to criteria of thenational committee for Clinical Laboratory Standars by means coli of Kirby-Bauerdisk diffusion method. The reference strains were Staphylococcus ATCC25923.We use the statistical analysis software, which is SPSS13.0, for data analysis. A1:1 case-control study was performed in two group patients' data. Fourteen possiblefactors were chosen, including: Tracheotomy (X1), Urinary tract intubation (X2), useof the third generation cephalosporins over three days (X3), the basis of chronicdiseases (X4), surgery (X5), arteriovenous intubation (X6), hormones and otherimmunosuppressant drugs chemotherapy (X7), Inhale oxygen (X8), mechanicalventilation (X9), Venous catheter system (X10), age greater than 60 years (X11),Admitted to ICU (X12), Hospitalization time＞=20 days (X13), prophylactic use ofantibiotics (X14). Multivariated analysis was applied to all key variables, which weresignificantly associated with the outcome in univariate analysis by using a logisticregression model to identify the risk factors.ResultsExcluding that Methicillin-resistant epidermidis Staphylococcus is sensitive tovancomycin and teicoplanin, its resistance to other antibiotics was significantly higherthan methicillin-sensitive staphylococcus. Single factor analysis removed that trachealintubation or tracheostomy, application generation cephalosporins than 3 three days,hormones and other immunosuppressants, chemotherapy drugs, arterio-venouscatheterization, based chronic disease and age older than 60 years of age six factors aresignificantly associated with the genotype. Use these six factors to do thenon-conditional logistic regression analysis of factors, and the results show thosethree-generation cephalosporins old than three days, hormones and otherimmunosuppressants, chemotherapy drugs, and arteriovenous intubation are independent risk factors for MRSE infection.DiscussionBecause of having the mecA gene, MRSE is the resistant toβ-lactam antibiotics;on the other hand, with the mechanisms of destroying the active- enzyme, MRSE isalso resistant to non-beta-lactam antibiotics (such as aminoglycoside). This sensitivitytest results show as followed: MRSR has highly resistance toβ-lactam antibiotics likethe genotype of penicillin (including enzyme inhibitor compound), cephalosporins(including third-generation cephalosporins), carbapenem, for which the resistant rate is100%; For fluoroquinolones, gentamicin, tetracycline, erythromycin, lincomycin andco-trimoxaz, the resistance rates are about 50% or more and it performs to the multipledrug -resistance; The resistant rate will never drop in the four years, except gentamicin,lincomycin, co-trimoxazole, and the resistant rates for others don't change a a lot;MRSE is extremely sensitive to vancomycin, for which the resistant rate is 0%; It ishighly sensitive to teicoplanin.; It is also more sensitive to rifampin, for which theresistant rate is below 25%. MRSE has become an important pathogen in hospital,whose multiple drug -resistance is very serious, and it is very difficult to cure inclinical..The most of Staphylococcus epidermidis bacteria are MRSE, which have thehospitalization for long time, and the high mortality. The factors of MRSE are a lot,and the main reasons are the using of antibiotics, hormones and otherimmunosuppressants, chemotherapy drugs, the arteriovenous intubation. The detectionof MRSE should be strengthened, so to prevent the prevalence MRSE what needs to dois monitoring bacteria in the high-risk areas of hospital, and rational usingantibiotics, hormones and other immunosuppressants, chemotherapy drugs in clinical,keeping strictly aseptic operation, and reducing arteriovenous indwellingcatheterization time.Conclusion1. Excluding that Methicillin-resistant epidermidis Staphylococcus is sensitive to vancomycin and teicoplanin, its resistance to other antibiotics was significantlyhigher than methicillin-sensitive staphylococcus.2. Staphylococcus epidermidis infections are mostly MRSE bacteria, high mortality,and hospitalization for long time.3. Methicillin-resistant epidermidis Staphylococcus is caused by multi-factors, usingthree-generation cephalosporins more than three days, hormones and otherimmunosuppressants, chemotherapy drugs, arteriovenous intubation are areindependent risk factors for MRSE infection. |
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