CHARACTERIZATION OF CLOSTRIDIUM DIFFICILE ISOLATED FROM DIARRHEAL PATIENTS IN A TERTIARY-CARE HOSPITAL, KARNATAKA, SOUTH INDIA.

Increase in Clostridium difficile infection in tertiary-care hospitals in Karnataka, South India with a paucity of data on antibiotic susceptibility and genetic characteristics of the pathogen from this region of the country necessitated this study. From April 2012 to December 2014, 480 hospitalized antibiotic-associated diarrhea cases with a history of antibiotic treatment in the previous three weeks were enrolled. Sixteen percent of the samples were positive for C. difficile toxins A and B by rapid enzyme immunoassay, anaerobic culture and multiplex PCR. In 40 representative strains, minimum inhibitory concentrations (MICs) determined by E-test revealed that 39 strains were resistant to imipenem and moxifloxacin (MIC > 32 µg/ml), 38 to clindamycin (MIC > 256 µg/ml) and 19 to tetracycline (MIC > 4 µg/ml), while all 40 strains were susceptible to ampicillin (MIC < 2 µg/ml), ampicillin sulbactam (MIC < 8 µg/ml), metronidazole (MIC < 8 µg/ml) and vancomycin group (MIC < 2 µg/ml). Pulsed field gel-electrophoresis (PFGE) of 13 representative strains grouped them into three clusters: cluster A consisting of two strains having > 65% similarity, cluster B of 6 strains with 100% similarity (considered clonal) and 3 strains with > 85% similarity, and cluster C of 2 strains with 50% similarity. Clusters A and C contained unrelated strains having different antibiograms. Periodic monitoring of resistance profiles with epidemiological typing by PFGE should aid in interpretation of emerging drug resistant C. difficile clones.

Decreased susceptibility to antimicrobials among Shigella flexneri isolates in Manipal, South India--a 5 year hospital based study.

Shigellosis is endemic in many developing countries and an important cause of bloody diarrhea worldwide. Our study was undertaken as a continuation of our earlier study during 2001 - 2006.The aim of this study was to monitor changes in Shigella serogroups and resistance patterns to antimicrobials among Shigella isolates. Two thousand one hundred fecal samples were obtained from patients with diarrhea during June 2006-June 2011. Isolates were identified by standard microbiological techniques as Shigella spp and the disk diffusion method was used to determine antimicrobial susceptibility following CLSI guidelines. Of the 2,100 fecal samples, 77 (3.7%) contained Shigella spp, of which 73 (94.8%) were S. flexneri, 3 (3.9%) were S. sonnei and 1 (1.3%) was S. dysentriae type 1. S. boydii was not identified. One hundred percent resistance was noted against nalidixic acid. There were high levels of resistance to other antimicrobials: ampicillin (100%), Co-trimoxazole (89.6%), tetracycline (84.4%), ciprofloxacin (87%) and norfloxacin (83.1%). Most of the isolates were susceptible to ceftriaxone except for 2 isolates of S. flexneri. Antibiotic treatment of shigellosis is needed to prevent mortality. Increasing fluoroquinolone resistance leaves us dependent on third generation cephalosporins for treating shigellosis. Emerging resistance to these cephalosporins was seen in our study.

Changing patterns of antimicrobial susceptibility of Shigella serotypes isolated from children with acute diarrhea in Manipal, South India, a 5 year study.

This study was carried out to determine the current pattern of Shigella serogroups and their antimicrobial resistance in children with acute gastroenteritis in Manipal, South India. A total of 1,200 stool samples were collected from April 2001 to May 2006 in children suffering from acute gastroenteritis attending the out-patient department of pediatrics at Kasturba Hospital, Manipal, South India. These samples were cultured for enteric pathogens. The isolates were confirmed to be Shigella by biochemical reactions and slide agglutination tests using specific antisera. Antimicrobial susceptibility was performed using an agar diffusion technique method following the National Committee for Clinical Laboratory Standard guidelines. Of 1,200 stool samples, 68 (5.6%) were positive for Shigella spp, 31 (45%) were Shigella flexneri followed by S. sonnei in 20 (31%), S. boydii in 10 (15%), and S. dysenteriae in 6 (8%). Of the 68 isolates, 58 (85.7%) showed resistance to various drugs and 47 (70%) were resistant to two or more drugs. Resistance to trimethoprim-sulfmethoxazole, tetracycline, nalidixic acid and ampicillin was observed in this study. All the strains were resistant to nalidixic acid (100%) but sensitive to cefotaxime and ceftriaxone.