Antimicrobial Resistance Pattern of Streptococcus Pneumoniae with Reference of Penicillin Resistance

Abstract

Streptococcus pneumoniae (pneumococcus) is the leading bacterial cause of infection worldwide, ranging from common infections such as otitis media to life threatening invasive infections such as Sepsis, Meningitis and Pneumonia. For many years Penicillin provided very effective treatment for pneumococcal infections. However, the last two decades have seen the emergence of pneumococcal strains with resistance to Penicillin. AST with special reference to Penicillin was determined along with the minimum inhibitory concentration (MIC) of penicillin resistant strains by standard method. Total 105 Streptococcus pneumonia strains were included in the study.  Out of 105 Streptococcus pneumoniae only 22 showed resistance to Penicillin and Oxacillin by disc diffusion. These 22 resistant samples were tested for MIC  by agar dilution method. Result was compared with standard MIC protocol according to which MIC value less than equal to 0.06 mg/L is considered as sensitive and 0.12-2mg/L as intermediate and greater than 2 mg/L as resistant. Out of 22 resistant samples, 18.81% showed intermediate sensitivity to Penicillin whereas the remaining 81.81% were sensitive to penicillin and no resistance to Penicillin was observed. Hence it was observed that although tedious and time consuming MIC method to determine resistance to Penicillin is more accurate method as compared to disc diffusion test which is used more widely.

Keywords: Streptococcus pneumoniae, antibiotic sensitivity, Minimum Inhibitory Concentration