Background Pneumococcal infections pose a global threat to public health and pneumococcal nasopharyngeal carriage is the main factor of invasive infection development in the community. In addition, the overuse of antibiotics has contributed in the development of antibiotic-resistant pneumococcal strains.
Objectives To determine the pattern of antibiotic susceptibility of isolated Streptococcus pneumoniae strains of healthy nasopharyngeal carriers 6 to 36 months of age in all districts of Cyprus.
Materials and methods A single nasopharyngeal swab was collected with a sterile rayon tip swab from 1105 healthy children 6–36 months of age, between October 2012 and September 2013. Data on possible risk factors was collected using an interview-based questionnaire. Bacteria was characterised by colony appearance, Gram staining, optochin susceptibility and bile solubility tests. Antibiotic susceptibilities were determined by disc diffusion method and MICs for penicillin and cefotaxime were determined by the E test method.
Results 280 strains were isolated. The overall nasopharyngeal carriage rate was 25, 34%. Antibiotic susceptibility pattern was as following: penicillin 21.79% intermediate, 3.21% resistant; cefotaxime 3.21% intermediate, 2.86% resistant; co-trimoxazole 7.14% intermediate 17.14% resistant; erythromycin 0.71% intermediate, 26.79% resistant; tetracycline 1.79% intermediate 12.50% resistant; clindamycin 0.71% intermediate, 19.64% resistant. All isolates were susceptible to chloramphenicol. Six out of the 9 (66.6%) penicillin-resistant pneumonococci were multi-resistant strains. Five were resistant to erythromycin, three to clindamycin and five to cotrimoxazole. Two strains were resistant to all above antibiotics. Seven (4.4%) out of 159 carriers who received at least once antibiotic treatment the last year were resistant to penicillin, whereas the respective percentage for those carriers not receiving any antibiotic treatment was only 1.6% (2 out of 121).
Conclusion The high prevalence of antibiotic-resistant pneumonococci in Cypriot carriers aged 6 to 36 months of age underline the need of continuous surveillance of Streptococcus pneumoniae. Moreover, the results of this study is a useful tool for the Cypriot clinicians to guide the local empiric therapy for pneumococcal infection.