Abstract
A total of 525 isolates belonging to 10 different species of Viridans Group Streptococci (VGS) viz., Streptococcus anginosus (196), S. morbillorum (85), S. mutans (76), S. mitis (60), S. uberis (34), S. intermedius (24), S. sanguis (20), S. oralis (18), S. salivarius (07) and S. acidominimus (05) were used for determination of antibiotic susceptibility pattern against 24 different antibiotics by standard disc diffusion method. Overall, the highest incidence of resistant strains was noted against Erythromycin (48.4%), followed by Streptomycin (39.0%), Gentamicin (39.0%), Doxycycline (36.6%), Tobramycin (33.1%), Amoxicillin (32.4%), Tetracycline (31.6%), Levofloxacin (31.2%), Chloramphenicol (26.1%), Rifampicin (25.3%), Ciprofloxacin (24.8%), Penicillin (22.5%), Vancomycin (21.7%), Clarithromycin (21.1%), Clindamycin (19.0%), Azithromycin (16.6%), Linezolid (4.0%), Trimethoprim (2.7%), Ceftazidime, Cefazolin, Cefotaxime (2.0%, in each case), Teicoplanin (1.5%), Cephalothin (1.7%) and Imipenem (1.1%). The present study also determined the incidence of multi-drug resistant (MDR) strains among VGS, only 5.5% isolates were found resistant to a single antibiotic, 4.0% isolates were resistant to 2 antibiotics while 41% isolates were resistant to more than 3 antibiotics. The emergence of multi-drug resistance was also noted with respect to species. The highest incidence rate was found among S. salivarius (85.7%, 6/7), followed by S. mutans (80.3%, 61/76), S. acidominimus (80.0%, 4/5), S. uberis (79.4%, 27/34), S. intermedius (79.2%, 19/24), S. morbillorum (70.6%, 60/85), S. oralis (61.1%, 11/18), S. anginosus (50.0%, 98/196), S. sangius (45.0%, 9/20) and S. mitis (41.7%, 25/60).
