ABSTRACT
Objective To study the characteristics of antimicrobial resistance and molecular epidemiology of Staphylococcus aureus (S .aureus)in the intensive care units(ICUs)of a hospital.Methods Clinical isolates of S .aureus collected from ICUs between January and December 2014 were identified and performed antimicrobial susceptibility testing,then typed by staphylococcal protein A (spa)typing and multilocus sequence typing (MLST) methods.Results Of 160 isolates of S .aureus ,120 (75.00%)were methicillin-resistant S .aureus (MRSA). Resistance rates of MRSA to erythromycin,clindamycin,and levofloxacin were all > 80%;methicillin-sensitive S .aureus (MSSA)were sensitive to cefazolin,resistance rates to erythromycin,clindamycin,and levofloxacin were 62.50%,35.00%,and 10.00% respectively.spa typing and MLST results showed that the main types of 120 isolates of MRSA were ST239-t030,ST239-t037,and ST5-t2460,the major epidemic strains were ST239-t030 (n=105,87.50%),and were isolated from 8 ICUs;MSSA had more types,ST59-t437 were detected only from depart-ment of neurology(n =8)and department of digestive diseases(n =2),ST6-t701 ,ST398-t3625,ST398-t1793,and ST121-t2092 were isolated from departments of neurology(n=7),anesthesiology(n=5),neurosurgery(n=4),and cardiac surgery(n=4)respectively.Conclusion Isolation rate of MRSA in ICUs in this hospital is high,ST239-t030 is the main type,which prevailed in hospital;different types of MSSA have epidemic trends in various departments.
ABSTRACT
Objective To investigate drug resistance and genotypes of methicillin-resistant Staphylococcus aureus (MRSA) isolated from intensive care unit (ICU). Methods MRSA strains were isolated from patients, medical staff and environment of hospital ICUs. Disk diffusion (K-B method) was used for drug resistance testing; Staphylococcal cassette chromosome mec (SCCmec) and Staphylococcal protein A (spa) typing methods were used for genotyping and identifying the homology. Results There were 78 strains of Staphylococcus aureus isolated including 62 isolates of MRSA, which were mainly from the burn ICU (22, 35.48%). Among 62 MRSA strains, 50 were hospital acquired strains, in which 43 isolates were of SCCmec Ⅲ, 4 of SCCmec Ⅰ and 3 of SCCmec Ⅱ. Twelve isolates could not be typed. Twenty-eight out of 37 hospital acquired isolates were typed by spa typing as SCCmec Ⅲ-t030, which belonged to the same clone. Conclusion MRSA in ICU is multi-drug resistant and SCCmec Ⅲ-t030 is the most prevalent genotype, which indicates that clinical MRSA strains and environmental MRSA strains may be homologous.