Surveillance on infections caused by communityassociated and healthcareassociated MRSA

Abstract:

ObjectiveTo analyze the drug resistance of communityassociated methicillinresistant Staphylococcus aureus (CAMRSA) and healthcare associated MRSA(HAMRSA), so as to provide reference on empirical antimicrobial  therapy for treating MRSA infection. MethodsMRSA isolated from clinical specimens from surgical department and intensive care unit (ICU) in a hospital between January 2006 and December 2008 were analyzed retrospectively , distribution and drug resistance of CAMRSA and HAMRSA were analysed statistically.ResultsEightseven strains were from ICU , the sources were as follows: 71 strains were from sputum, 6 from throat swabs, 5 from wound secretion, 2 from blood and venipuncture tubes respectively, and 1 from pleural effusion; HAMRSA accounted for 98.85%(86/87). Fortyone MRSA strains from surgical department were all isolated from wound pus, CAMRSA accounted for 48.75%(20/41) , and showed an increasing tendency year by year, which increased from 20.00% in 2006 to 71.43% in 2008 (χ2=8.24, 0.01<P<0.025). Antimicrobial susceptibility test results showed that the resistant rates of  HAMRSA to clindamycin,tetracycline,erythromycin,ciprofloxacin,levofloxacin , and gentamycin was 98.13%,98.13%,100.00%, 100.00%,100.00% ,and 100.00% respectively, which was significantly higher than that of CAMRSA (which was 42.86%,66.70%,33.33%,0.00%,0.00% , and 4.76% respectively), there was significant difference between the two respectively(all P<0.005).ConclusionThere is an increasing tendency of CAMRSA infection in hospitalized patients , drug resistance of CAMRSA is different from that of HA MRSA , CAMRSA strains are usually susceptible to nonβlactam agents.