Persistence of Corynebacterium diphtheriae in Delhi & National Capital Region (NCR).

Despite the introduction of mass immunization, diphtheria continues to play a major role as a potentially lethal infectious disease in many countries. Delay in the specific therapy of diphtheria may result in death and, therefore, accurate diagnosis of diphtheria is imperative. This study was carried out at National Centre for Disease Control (NCDC), Delhi, India, on samples of suspected diphtheria cases referred from various government hospitals of Delhi and neighbouring areas during 2012-2014. Primary identification of Corynebacterium diphtheriae was done by standard culture, staining and biochemical tests followed by toxigenicity testing by Elek’s test on samples positive for C. diphtheriae. The results showed persistence of toxigenic C. diphtheriae in our community indicating the possibility of inadequate immunization coverage.

Sensitivity index of antimicrobial agents as a simple solution for multidrug resistance in Salmonella Typhi.

BACKGROUND & OBJECTIVE: Multi drug-resistant (MDR) typhoid in India is an escalating problem. MDR isolates of Salmonella Typhi are on rise and are becoming a challenge for timely and appropriate treatment. Occurrence of per cent sensitive (%S), per cent resistant (%R) and per cent intermediate (%I) isolates may vary geographically and treatment decided on the basis of only one of these three subpopulations may lead to selection of inappropriate drug for treatment and thus treatment failure. Determination of sensitivity index (SI) of antimicrobial agents, instead of %S or %R subpopulations, may give clearer insight regarding selection of appropriate antimicrobial for treatment of typhoid. In present work, the data of sensitivity testing were analysed and interpreted both in terms of SI as well as %S, %I and %R. METHODS: A total of 205 isolates of Salmonella Typhi were collected during June 2000 and August 2002 from a network of five institutes- Lady Hardinge Medical College (LHMC, N=110), Ram Manohar Lohia Hospital (RML, N=14), Majeedia Hospital (MH, N=48), Lal's Pathology Lab (LAL, N=28) and All India Institute of Medical Sciences (AIIMS, N=5) on nutrient agar slopes. Of these, 142 isolates were subjected to phage typing and biotyping at National Salmonella Phage Typing Centre, New Delhi. Five isolates resistant to 3-7 and one isolate susceptible to all of total 12 antimicrobial tested were subjected to plasmid analysis. SI for various antimicrobials was determined as the ratio of %S and %R values derived form %RIS analysis using WHONET5. RESULTS: 18 (8.7%) isolates were susceptible to all tested antimicrobials and 124 (60%) were MDR. Of the 142 isolates, 103 were phage type E1 and biotype I. SI of antimicrobials rather than individual %S or %R or %I population presents a better criterion for interpretation of sensitivity testing data as well as selection of the most appropriate antimicrobial for timely treatment. Presence of 140, 48 and 23 Kb size plasmids in all 5 MDR isolates and none in susceptible isolate was observed. INTERPRETATION & CONCLUSION: Re-emergence of chloramphenicol sensitivity in Salmonella typhi was observed in the present study. Interpretation in terms of SI criteria warrants that reintroduction of chloramphenicol at present for treatment of typhoid may rebound resistance. Current empiric therapy used for treatment of typhoid may soon become ineffective. SI being a ratio will not only eliminate geographical variation of %RIS data but also its interpretation. SI can provide guidelines for clinicians in remote areas where facilities for sensitivity testing are not available.

Antimicrobial susceptibility pattern and prevalence of extended spectrum beta-lactamase (ESBLs) producing strains of Klebsiella pneumoniae from a major hospital in New Delhi.

Extended spectrum beta-lactamases (ESBLs) are plasmid mediated enzymes capable of hydrolyzing penicillins, broad spectrum-cephalosporins and monobactams. The ESBL producing K. pneumoniae strains are being reported from around the world including India. The present study was taken up to evaluate the ESBL production and in-vitro susceptibility of K. pneumoniae isolates from a hospital. The bacterial isolates collected during 2003 included 51 K. pneumoniae biochemically confirmed isolates from 395 patients admitted in various wards of a major hospital in New Delhi. The isolates were from pus, wound, pleural fluid, urine and tracheal aspirate of patients attending respiratory, urology and burns wards. Antimicrobial susceptibility was carried out by Kirby Bauer's disc diffusion technique using NCCLS criteria. A screening of ESBL production was done by Double-disc synergy test (DDST) and using E-test ESBL strips. The frequency of resistance among K. pneumoniae for the cephalosporins (cefoxitin, cefuroxime, cefotaxime, ceftazidime, and cefepime) and non-cephalosporins (aztreonam, piperacillin, chloramphenicol and trimethoprim-sulfamethoxazole) were in the range of 39.2-88.0% and 51.0-90.2% respectively. 14 different antimicrobial resistance profiles were recognized ranging from resistance to only four (n=6, 11.7%) to as many as ten (n=9, 17.7%). Among the 51 isolates of K. pneumoniae strains, a total of 36 (70.6%) could be identified as ESBL producers, that correlates with the high frequency of multi-drug resistant K. pneumoniae The study shows alarming rise in ESBL production among K. pneumoniae strains and high rate of resistance to a wide range of cephalosporin and non-cephalosporin group of antimicrobials.

Prevalence of diphtheria and tetanus antibodies in young adults in Delhi.

A total of 574 blood samples collected mainly from adult males, on a random basis, were tested for diphtheria and tetanus antibodies by Indirect Haemagglutination (IHA) test to find out the percentage of individuals with protective titres (> or = 0.015 IU/ml). A total of 502 (87.5 per cent) and 437 (76.2 per cent) of these had protective titres against diphtheria and tetanus respectively. The vaccination status of these subjects against diphtheria and tetanus was not ascertainable. The relevance of these findings is discussed.

Nasopharyngeal carriage of Neisseria meningitidis in general population and meningococcal disease.

Nasopharyngeal carriage of Neisseria meningitidis was determined in the normal healthy population in Delhi at monthly intervals for a period of 2 years from January, 1986 to December, 1987. Of a total of 6513 individuals screened only 107 (1.64 per cent) were found to carry Neisseria meningitidis serogroup A. There was no age and sex difference in carriage. During the same period, data of laboratory confirmed cases of meningitis due to N. meningitidis serogroup A was obtained from 6 hospitals of Delhi which acted as sentinel centres. Of the total 11,870 pyogenic C.S.F. samples processed, only 557 (4.69 per cent) were due to N. meningitidis serogroup A. There was no correlation observed between the nasopharyngeal meningococcal carriage in the healthy population with the disease prevalence. There was no seasonal variation in nasopharyngeal carriage though upsurge in the number of meningococcal meningitis cases was noticed from January to April.