Characterization of Streptococcus pneumoniae isolates from India with special reference to their sequence types.

INTRODUCTION: Streptococcus pneumoniae is a major cause of mortality and morbidity in young children and the elderly. In the present study we evaluated antimicrobial susceptibilities, serotypes, and sequence types of pneumococcal isolates recovered in New Delhi, India. METHODOLOGY: A total of 126 clinical isolates of Streptococcus pneumoniae were investigated. They were subjected to disk diffusion susceptibility testing, broth microdilution testing, serotyping and multilocus sequence typing. RESULTS: Broth microdilution assay showed that 5%, 20% and 23% of the isolates exhibited resistance to penicillin, erythromycin and ciprofloxacin, respectively. Serotypes19, 1 and 6 were more frequently isolated. Thirty per cent of the strains were comprised of serotypes 1, 3, 5, 19A and 7F, which are not included in the seven-valent vaccine. Fifty-nine isolates were typed using multilocus sequence typing. Thirty new sequence types were encountered in this study. Only one clonal complex with 4 isolates was seen; 11 clonal complexes and 96 sequence types (STs) were observed among 115 Indian isolates. Only 18 of the 96 STs were found globally, of which only 4 STs were found in many countries with larger numbers. CONCLUSIONS: This study identifies the non-vaccine serotypes of Streptococcus pneumoniae circulating in India. It is important that an appropriate vaccine which covers all serotypes is used in the region.

Amplification of mecA gene in multi-drug resistant Staphylococcus aureus strains from hospital personnel.

BACKGROUND: Antibiotic resistance is common among bacterial pathogens associated with both community acquired and nosocomial infections. In view of the present problem of drug resistance we investigated the prevalence of methicillin resistant Staphylococcus aureus (MRSA) and amplified the mecA gene in the isolates from the hand swabs of the hospital personnel. METHODOLOGY: The nuc gene was amplified to characterize these isolates at species level. The S. aureus isolates were analyzed for their susceptibility to different classes of antibiotics using the disk diffusion method. The spot inoculation test was performed to detect methicillinase production in these isolates. RESULTS: In the screened isolates of S. aureus, 14.2 and 15 kb of plasmids were present. These isolates showed pronounced resistance against beta-lactam antibiotics including second- and third-generation cephalosporins, aminoglycosides, macrolides and fluoroquinolone. Some of the isolates included in this study were resistant to three or more antibiotics. Expression of methicillinase was detected by spot inoculation test, and a few of the isolates were found to produce methicillinase. Moreover, mecA gene was also amplified. Of 17 isolates only 7 showed presence of mecA gene. CONCLUSION: This study highlights the emerging trend of multiple drug resistance in S. aureus strains isolated from hospital personnel working in a premier hospital in North India.