Rapid Diagnosis And Homology Analysis Of Methicillin-resistant Staphylococcus Aureus(MRSA) And Acinetobacter Baumannii(A.baumannii) Strains In Burn Unit

Part I Comparison of three methods for detection of MRSA andA.baumannii from patients of department of BurnObjective: In order to shorten the diagnosis periods of MRSA and A.baumannii, andto provide clinical evidence of MRSA and A.baumannii infection, three methods, includinggermiculture common PCR and multiplex PCR were compared for detection of MRSA andA.baumannii and the diagnosis periods of the three methods were also compared.Methods: Germiculture method common PCR assay and multiplex PCR assay wereused to detect128cases samples collected from the department of Burn in the first affiliatedhospital of Soochow University, including100patients’ wound secretions and28sputumsamples(from January2013to December2013). The positive detection rate and the time ofconfirmed diagnosis of three methods for MRSA and A.baumannii were compared.Results: The positive detection rate of MRSA and A.baumannii of germiculturemethod was45.3%and30.5%, respectively. And the detection rate of MRSA andA.baumannii of common PCR assay and multiplex PCR assay was identical to germiculturemethod, but the time of confirmed diagnosis of PCR assays(6hours) was significantlyshorter than germiculture method(72hours). Moreover, multiplex PCR could detect MRSAand A.baumannii simultaneously.Conclusion: Compared with germiculture method, there was no difference in detection rate of MRSA and A.baumannii by common PCR assay and multiplex PCR assay. But PCRassay, especially multiplex PCR assay can significantly shorten the detection time, and candetect MRSA and A.baumannii within6hours, which is economically effective fordiagnosis of MRSA and A.baumannii, and could prevent A.baumannii use of antibiotics,reduce burden of patients.Part Multiplex PCR for detection of MRSA and A.baumannii from surroundings ofdepartment of BurnObjective: In order to study the way of infection of MRSA and A.baumannii indepartment of Burn in the first affiliated hospital of Soochow University, multiplex PCRmethod was used to detect MRSA and A.baumannii from surroundings of burn ward.Based on the detection results, effective measures were given to cut off the transmission inburn wards, and to prevent outbreak of MRSA and A.baumannii infection in burn wards.Methods: Using multiplex PCR assay to detect MRSA and A.baumannii frommedical stuffs’ hands, air and patients’ beds in the burn wards.Results:1. For medical stuffs’ hands: no MRSA and A.baumannii were detectedbefore and after operation on patients.2. For air samples: Four air samples from the burn wards with patients of infection ofMRSA or A.baumannii was detected MRSA or A.baumannii. One air sample from burnward with a patient of infection of MRSA failed to detect MRSA. No MRSA andA.baumannii was detected in the air sample from the burn wards with none patients ofinfection of MRSA or A.baumannii.3. For patients’ beds: Eight mattresses with patients of infection of MRSA and(or)A.baumannii were detected with MRSA and(or) A.baumannii. One mattress with MRSAinfection failed to detect MRSA, and three samples detected no MRSA and A.baumanniiwithout patients of infection of MRSA and A.baumannii in the mattress.Conclusion: Based on the detection results of MRSA and A.baumannii from patientsand surroundings where patients live, we concluded that the infection of MRSA and A.baumannii in the burn wards was closely related to the quality of the environment (airand sheets) in the burn wards, which also indicated that there was cross infection betweensurroundings and patients’ wounds. Therefore, strengthening the disinfection work of burnward surroundings, strict air disinfection, and regularly monitoring the surroundings, is ofgreat significance to prevent the outbreak of MRSA and A.baumannii infection.Part Homology analysis of MRSA and A.baumannii strains from patients andsurroundings in department of BurnObjective: In order to prevent the outbreak of infection of MRSA and(or)A.baumannii, ERIC(enterobacterial repetitive intergenic consensus)-PCR was used toanalysis the homology of MRSA and A.baumannii collected from wounds, sputum ofpatients and surroundings of burn wards.Methods: ERIC-PCR was used to amplification the DNA of5MRSA strains isolatedfrom wound secretion of patients,3MRSA strains isolated from sputum of patients2MRSA strains isolated from the air of corresponding burn ward, and4MRSA strainsisolated from mattress of patients. Meanwhile, DNA of4A.baumannii strains isolatedfrom wound secretion of patients,4A.baumannii strains isolated from sputum of patients2A.baumannii strains isolated from the air of corresponding burn ward, and2A.baumannii strains isolated from mattress of patients was also amplified by ERIC-PCR.Results: The homologous analysis showed that MRSA strains and A.baumanniistrains separated from the same burn ward are of the same genotype or similar genotype.Conclusion: Our results showed that the genotype of MRSA and A.baumanniiisolates from the same burn ward were identical, indicating there were cross-transmissionbetween patients and surroundings of burn wards. Special efforts need to strengthen themonitoring of nosocomial infection, to emphasize the sterile concept to the medical stuff,to reduce the risk of cross-transmission. Meanwhile, strict disinfection and isolationsystem should be performed to reduce the occurrence of nosocomial infection. Finally,hand hygiene plays an important role in control of nosocomial infection, and should be carried out throughout the whole treatment process.