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Antimicrobial susceptibility of invasive Streptococcus pneumoniae isolates from children in Athens, 20032008

Abstract number: R2384

Matsas M., Kalogeras G., Antonaki G., Papadimitriou M., Lebessi E., Foustoukou M., Kallergi K.

Objectives: To investigate the resistance patterns of S. pneumoniae isolates from patients with invasive pneumococcal disease (IPD), hospitalized at "P.&A. Kyriakou" Children's Hospital during a six-year period (Jan 2003 to Dec 2008).

Methods: Invasive isolates were reviewed using the laboratory archives and the patient charts. Susceptibility to penicillin (PN), cefotaxime (CTX), erythromycin (ER), clindamycin (CL), trimethoprim-sulfamethoxazole (SXT), tetracycline (TE), rifampin (RF), chloramphenicol (C), vancomycin (VAN), ofloxacin (OFL) was tested using the disk diffusion method, following the CLSI guidelines. MICs to PN, amoxicillin (AMX) and CTX were determined using Etest.

Results: During the study period, 126 invasive pneumococcal isolates (IP) were identified (114 blood, 9 CSF, 3 pleural fluid). Yearly distribution of IP from 2003 to 2008 was as follows: 30, 20, 21, 20, 20, 15. Susceptible to all antimicrobials tested were found to be 60% (76/126). Non-susceptible to PN (PNSP) were 18% (23/126). According to the MICs 21/23 (91.3%) were intermediate and 2/23 (8.7%) were fully resistant to PN. Resistance rates to other antimicrobials were significantly higher in the group of PNSP isolates in correlation with PN susceptible isolates (p < 0.05). Analytically, among the PNSP isolates, resistance to ER, CL, SXT, and TE was 56.5%, 34.7%, 43.4%, and 17.3%, while among PN susceptible isolates resistance to ER, CL, SXT, and TE was 20.3%, 4.8%, 6.8%, and 2.9%, respectively. Multidrug resistance reached 47.8% of PNSP strains, but only 3.8% of PN susceptible isolates. Various antibiotic resistant phenotypes were observed. Macrolide-resistance was 27% [M-phenotype 62% (21/34), MLSBc 38% (13/34)]. Yearly incidence of PNSP from 2003 to 2008 was as follows: 7%, 20%, 14%, 30%, 10%, 40%. Yearly incidence of ER – resistant isolates was: 3%, 20%, 14%, 15%, 0%, 13%. The most active antimicrobials were AMX, CTX, VAN, RF, C to which no resistance was found.

Conclusions: Antimicrobial resistance of S. pneumoniae remains a significant problem in our area. The increase of penicillin and macrolide resistance from 2003 through to 2008 was worrisome. The decrease of resistance observed during 2007 could be related with the introduction of PCV7 into the national immunization program in 2006. Continuous surveillance of antimicrobial resistance is needed to determine the impact of PCV7 and other newer vaccines in pediatric population.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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