ANTIMICROBIAL SUSCEPTIBILITY OF NASOPHARYNGEAL STREPTOCOCCUS PNEUMONIAE STRAINS TO BETA-LACTAMS

SAŽETAK Asimptomatsko nazofaringealno kliconoštvo vrste Streptococcus pneumoniae (S. pneumoniae), rašireno poglavito među malenom djecom, pridonosi širenju bakterije u populaciji, te razvoju bolesti. Utvrđivanje prevalencije kliconoštva i osjetljivosti sojeva koji kolaju u populaciji kao mogućih izvora infekcije, pridonosi unapređenju liječenja i preventivnih mjera1,2. U radu je u prvome redu analizirana incidencija pneumokoka otpornih na antibiotike u izvanbolničkoj populaciji. S. pneumoniae izoliran je iz 2464/33.139 (7,4%) uzoraka. U razdoblju od 1. siječnja 2003. do 31. prosinca 2006., disk-difuzijskim postupkom ispitana je osjetljivost 2464 izolata na eritromicin, azitromicin, klaritromicin, klindamicin, tetraciklin i trimetoprim sa sulfometoksazolom. Za 493 (20%) izolata sa smanjenom osjetljivošću na penicilin, što je ustanovljeno oksacilinskim diskom, E-testom (AB Biodisk) određene su minimalne inhibitorne koncentracije (MIK) penicilina. Od 2464 izolata, na penicilin je bio osjetljiv 1971 izolat (80%), a umjereno osjetljiva bila su 493 izolata (20%). Minimalne inhibitorne koncentracije sojeva smanjene osjetljivosti na penicilin, kretale su se od 0,125 do 1,5 μg/ml. Na eritromicin, azitromicin i klaritromicin ustanovljena je otpornost u 418 (18%) ispitanih sojeva, 370 (16%) izolata bilo je otporno na klindamicin, 297 (11%) na tetraciklin, a 543 (22%) izolata bila su otporna na trimetoprim sa sulfometoksazolom.ABSTRACT The asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae (S. pneumoniae) is widely prevalent in children and has been related to the development of disease and the spread of the pathogen.The bacteria carried in the nasopharynx of healthy children reflect the infection- causing strains currently circulating in the community, and so studies of the prevalence of different pathogens and their resistance patterns can provide useful indications for more rational therapeutic and preventive strategies1,2. Present studies have been focused mainly on the incidence of antibiotic-resistant pneumococci among out-patients. S. pneumoniae was isolated from 2464/33.139 (7.4%) specimens. From 01. 01. 2003. till 31. 12. 2006. the susceptibility of 2464 Streptococcus pneumoniae strains to erythromycin, azithromycin, clindamycin, tetracycline, and trimethoprim-sulfamethoxazole was tested using the disk diffusion method. In (86) isolates with reduced sensitivity to penicillin (as determined with oxacillin disk method), minimal inhibitory concentrations (MIC) of penicillin and ceftriaxone was tested by the E-test (AB Biodisk) method. Sensitivity to penicillin was found in 1971 (80%) of the 2464 Streptococcus pneumoniae while 493 (20%) of the isolates demonstrated decreased susceptibility. Isolates with reduced sensitivity to penicillin had MICs from 0.125 to 1.5 μg/ml. 418 (18%) isolates were resistant to erythromycin, azithromycin and clarythromicin, 370 (16%) to clindamycin, 297 (11%) to tetracycline, and 543 (22%) to trimethoprim-sulfamethoxazole