Serotype distribution and antibiotics susceptibility pattern of Streptococcus pneumonia in Iran.

Background: The development of antibiotic resistance among Streptococcus pneumoniae strains has caused significant health problems worldwide.

Objectives: The aim of this study was to determine antibiotic resistance pattern and serotypes distribution of Streptococcus pneumoniae strains isolated from clinical specimens.

Material And Methods: A total of fifty Streptococcus pneumoniae strains were isolated from Tehran Hospital's laboratory from 2008 to 2012. Antimicrobial susceptibility testing was performed using broth microdilution method and minimum inhibitory concentration (MIC) of each strain was determined. to verify the resistant strains and demonstrate the presence of antibiotic resistant genes, the PCR was performed.

Results: The study showed that three strains (6%) and six strains (12%) indicated intermediate resistance and complete resistance to penicillin, respectively, 58% strains were susceptible to ceftazidime, two ones (4%) indicated resistance to ciprofloxacin, one (2%) indicated intermediate resistance to ceftriaxone , two strains (4%) indicated complete resistance and four (8%) strains indicated resistance to vancomycin.

Conclusions: The emergence of Streptococcus pneumoniae strains with multiple resistance needs permanent monitoring of antibiotic susceptibility patterns of clinical isolates. We have found that ceftazidime is not a suitable drug for choosing the treatment of pneumococcal infections.