Background: The qnr gene family consists of plasmid mediated quinolone resistance (PMQR) genes that confer low level resistance to nalidixic acid and reduced susceptibility to ciprofloxacin. At our tertiary care referral centre in Chandigarh, which caters to a large population of 5 neighboring states, antibiotic resistance in Shigella is being constantly monitored Methods & Materials: We screened 139 S.flexneri and 38 S. dysenteriae serotype 1 isolated during 2001 to 2011,for PMQR (qnrA, qnrB, qnrS, aac(6′)-Ib-cr and qepA) genes. MICs were determined for nalidixic acid and ciprofloxacin by E-test. The isolates were classified as susceptible (MICs <0.5 mg/L) or resistant (MICs ≥1 mg/L) to ciprofloxacin; susceptible (MIC ≤ 16) or resistant (MIC ≥ 32) to nalidixic acid respectively. Those positive for PMQR were tested for ESBL (CLSI). Results: Eleven (6.12%) isolates, were found to harbor PMQR, out of which 2 were positive for qnrS1 gene (S. flexneri),while 9 for aac(6′)-Ib-cr gene (6 S. flexneri and 3 S. dysenteriae). No strain harbored both genes. None were positive for qnrA, qnrB, qnrD and qepA genes. Out of 11 PMQR positive isolates, 3 showed ciprofloxacin MIC of ≥32 mg/L while 9 strains were resistant to nalidixic acid with a MIC of > 128 mg/L, 3 were positive for CTX-M-15 and 1 for CMY-2 gene. The aac(6′)-Ib-cr gene was detected as early as 2002,combination of CTXM-15 with aac(6′)-Ib-cr appeared in 2005 and qnrS1 appeared recently in 2010. PMQR could not be the direct reason for quiniolone and fluoroquinolone resistance in these strains. Sequencing of gyrA and parC revealed three mutations on the QRDR of each of the 11 PMQR positive strains, thought to be primarily responsible for quinolone resistance phenotype Conclusion: After description of qnrS1 Shigella in Japan, China and USA, we report the first description of qnrS1 Shigella in India. Furthermore, combination of PMQR and CTXM-15 genes is being reported here for the first time in Shigella. The close association of aac(6′)-Ib-cr, with CTX-M-15 is of great concern as CTX- M-15 has emerged worldwide. The two qnrS1 strains detected were from 2010, indicating a relatively new appearance among Shigella in India.

In July 2002, an outbreak of cholera occurred in north India with two separate geographical foci. Pulsed field gel electrophoresis (PFGE) was previously used in typing a representative sample of these isolates. This study evaluates the usefulness of MALDI-TOF as an epidemiological tool for typing Vibrio cholerae isolates in comparison with PFGE and Amplified fragment length polymorphisms (AFLP). Forty-six isolates of V. cholerae isolated from stool of patients affected in the July 2002 outbreak were typed using MALDI-TOF. To validate its utility, clinical and environmental isolates previously characterized by PFGE and AFLP were included for dendrogram analysis. All 46 isolates were correctly identified by MALDI-TOF to species level. Two distinct clades appeared on dendrogram using MALDI-TOF corresponding to the two geographical foci of the outbreak. For the study of evolution of organisms from environment, AFLP was superior as it clearly demarcated clinical and environmental isolates. The outbreak was not due to a single clone but due to multiple clones circulating simultaneously, as was seen with PFGE also.

Background: Cronobacter sakazakii (formerly Enterobacter sakazakii) causes serious infections in infants with high mortality. Though contaminated powdered infant formula is the most common implicated vehicle, the organism has been isolated from other foods and environmental sources and infections have occurred among persons who did not consume or handle formula milk. There is significant underreporting of C. sakazakii infections in most countries and very little data is available from India. There is no information on human carriage, environmental sources and potential transmission routes of this pathogen from India. The aim of this study was to study the prevalence of this organism in North India (Haryana, Punjab and Chandigarh) and study the antibiotic resistance. Methods & Materials: A wide range of samples (n = 887) were collected from poultry farms, meat abattoirs (pork and mutton), dairy farms (pig stool, goat stool), human diarrhea stool samples and domestic environmental samples (water and soil) and processed for Cronobacter sakazakii. Presumptive C. sakazakii colonies were confirmed by MALDI-TOF. Antibiotic sensitivity was performed. Results: Incidence of Cronobacter sakazakii was found to be 7.1% with individual incidence of 3.37% in humans, 9.4% in goat meat, 11.1% goat feces, 5.9% in pork, 7% pig stool, 6.7% in chicken stool, 11.5% environment. Of the 63 isolates, maximum resistance was observed against ampicillin (50.8%), followed by ciprofloxacin (20.6%) and them meropenem (17.2%). Carbapenem resistance was found in both animal food source and human strains. Conclusion: Cronobacter sakazakii is part of fecal flora of humans as well as is carried by food production animals and is also present in domestic environment with potential risk of cross-contamination. The overall antibiotic resistance in human isolates was low in comparison to food animals and their fecal samples. A higher resistance in animal isolates could be due to rampant use of antibiotics as growth promoters in animals.

Purpose: Carbapenem-resistant Enterobacteriaceae (CRE) have emerged and disseminated widely causing a variety of infections. In India, the carriage of CRE in hospitalised patients has not been well-studied. Therefore, we conducted the present study to observe gut carriage rate of CRE in patients admitted to our tertiary care hospital. Methods: A total of 232 faecal swabs collected from consecutive stool samples from admitted patients were inoculated on ChromID extended spectrum β-lactamase plates and members of Enterobacteriaceae family were subjected to antibiotic susceptibility as per the Clinical Laboratory Standards Institute guidelines. Polymerase chain reaction for blaVIM, blaKPC, blaIMP and blaNDM-1 genes was performed. CRE was identified if the isolates showed resistance to either imipenem or meropenem or showed the presence of resistant genes. Risk factors of patients with or without CRE colonisation were also analysed. Results: A total of 232 faecal swabs yielded 252 Enterobacteriaceae isolates, of which 49 isolates from 42 patients showed the presence of CRE (occurrence 42/232; 18.1%); 27 isolates from 22 patients carried blaNDM-1, whereas 20 isolates from 17 patients possessed blaVIM gene. No isolate was positive for blaKPC and blaIMP genes. The CRE was common in both intensive care units (38.4%) and wards (46%) which may reflect the excessive use of broad-spectrum antibiotics in both these settings. The CRE was also found to have a significantly higher antimicrobial resistance as compared to non-CRE isolates. The logistic regression analysis of significance showed the presence of any indwelling device (P = 0.049) and nasogastric tube (P = 0.043) as independent risk factors for acquiring gut colonisation. Conclusions: The study is the first from India to show high CRE carriage in patients admitted to a tertiary care centre and emphasises the need of strict antimicrobial stewardship implementation in hospitals to prevent dissemination of multidrug-resistant CRE.

Laboratory diagnosis of shigellosis using conventional culture technique is limited by lower sensitivity and higher turnaround time. Here, we have evaluated the role of polymerase chain reaction from stool samples after enrichment in Escherichia coli medium for detection of Shigellae. The technique not only increased the sensitivity but also decreased the turnaround time.

Chryseobacterium spp are widely distributed in nature but data of their isolation from clinical samples is scanty. Here, we report the first case of AmpC producing C. gleum causing pyonephrosis in a patient having bilateral nephrolithiasis on double J (DJ) stent. The present isolate was resistant to vancomycin, erythromycin, clindamycin, carbapenems and ciprofloxacin and susceptible to tetracycline and minocycline. The patient was treated with tetracycline and recovered without the need for removal of the DJ stent. The environmental surveillance carried out to trace the nosocomial origin of the isolate was negative. Since antimicrobial susceptibility of this isolate is different from previous reports, we emphasise that in vitro susceptibility testing should be sought to choose optimal antimicrobial agents for these Nonfermentative Gram-Negative Bacilli (NFGNBs) with different susceptibility patterns.

Catheter associated bacteriuria is very common and there is a need to differentiate symptomatic CA-UTI from asymptomatic bacteriuria (CA-ASB) to rationalise antibiotic usage.

Bacterial flora in burn patients undergoes a change over a period of time and is dependent upon many factors. Study of burn flora is not only helpful in locating entry of multidrug resistant bacterial strains into the unit’s usual flora but also in determining current antibiotic susceptibilities.

BACKGROUND & OBJECTIVES:Multi drug resistant Shigellae pose a major threat in control of shigellosis with. Shigella dysenteriae being the most prevalent species at our centre before 1994. A gradual decrease in S. dysenteriae occurred over the years with a corresponding increase in S. flexneri which became the predominant serotype. From May to November 2003, an increase in number of patients admitted with clinical diagnosis of dysentery was noted in comparison to previous years, with a corresponding increase in the isolation of multi drug resistant S. dysenteriae. We report here the re-emergence of multi drug resistant S. dysenteriae at our tertiary care centre in north India after a gap of about 10 yr. Plasmid analysis of S. dysenteriae was also performed to study the origin and clonality of the isolates.METHODS:Stool samples were collected in Cary-Blair medium and processed by standard methods. Shigellae were confirmed by serotyping. Minimum inhibitory concentration was done by agar dilution method and E-test. Plasmid profiling of 18 isolates (16 S. dysenteriae 1 and 2 S. dysenteriae 2) was performed by modified alkali lysis method. Clinical details of patients were noted.RESULTS:A total of 64 patients with dysentery were admitted during the study period. Patients presented with unusually severe symptoms and six developed complications. Treatment failure with ciprofloxacin occurred in six patients who received cefotaxime and amikacin. There were 38 children below 5 yr of age. S. dysenteriae (18 isolates of S. dysenteriae 1 and 2 isolates of S. dysenteriae 2) were isolated from 20 of the 64 (31.2%) stool samples. S. dysenteriae re-emerged as the commonest isolate after a gap of nearly 10 yr. Fourteen of the 20 S. dysenteriae isolates were multi drug resistant; 12 were resistant to ciprofloxacin with MIC of 8-32 mug/ml. Plasmid profile analysis revealed that 6 of 11 ciprofloxacin resistant S. dysenteriae 1 had similar profiles.INTERPRETATION & CONCLUSION:Emergence of a clone of ciprofloxacin resistant S. dysenteriae 1 in north India is disturbing as treatment options in our geographic area are limited in view of already existing high drug resistance to nalidixic acid, co-trimoxazole and amoxycillin. A close monitoring of shifts in serogroup distribution and antibiotic resistance is required to guide clinicians for treatment of shigellosis.

BACKGROUND & OBJECTIVES The resistance of enteropathogenic bacteria to commonly prescribed antibiotics is increasing both in developing as well as in developed countries. Resistance has emerged even to newer, more potent antimicrobial agents. The present study was therefore undertaken to report the current antibiotic resistance in common bacterial enteropathogens isolated in a tertiary care hospital in north India. METHODS Faecal samples from 1802 patients were cultured for common bacterial enteropathogens and identified by standard methods. Antibiotic susceptibility was done by Stoke's disk diffusion method. The clinical and demographic profile of the patients was noted. RESULTS Stool specimens from 119 (88 male, 31 female) patients yielded Shigella, Salmonella, Vibrio cholerae or Aeromonas. Fifty two per cent (62/119) of patients were children and 70 per cent were below the age of 5 yr. Twenty seven patients developed hospital acquired diarrhoea. Among all enteropathogens, Shigella spp. was the commonest followed by non-typhoidal Salmonella (27), V. cholerae O1 El tor serotype Ogawa (19), Aeromonas spp. (14), Salmonella Typhi and S. paratyphi A (2 isolates each). Resistance to antimicrobial agents was common among all pathogens. Among shigellae an overall resistance of 63.6, 58.1 and 16.3 per cent was observed for nalidixic acid, cotrimoxazole and furazolidone respectively. Seven isolates of Shigella were resistant to ciprofloxacin, (18.5%) of non-typhoidal salmonellae were resistant to ciprofloxacin. V. cholerae were generally susceptible to tetracycline (only 1 isolate out of 13 resistant) and other drugs except nalidixic acid (89.5% resistance) and cotrimoxazole (77.8% resistance). INTERPRETATION & CONCLUSION Enteropathogens have developed high level resistance to first line agents used for empiric treatment of diarrhoea. Progressively increasing resistance to ciprofloxacin is a serious cause of concern.

BACKGROUND & OBJECTIVES:As a marked increase in the number of patients with candidaemia was reported in the first half (1991-1995) of the last decade at the Postgraduate Institute of Medical Education & Research, Chandigarh, India, the present study was aimed at determining further change if any, in the incidence and distribution of Candida species and their antifungal resistance pattern during the second half (1996-2000) of the same decade.METHODS:The patients with candidaemia were studied to determine the frequency of candidaemia and Candida species isolated during 1996-2000. One hundred Candida strains other than Pichia anomala (C. pelliculosa) were randomly selected from those isolates to evaluate antifungal susceptibility pattern against amphotericin B, 5-fluorocytosine, ketoconazole, fluconazole and itraconazole. The results were compared with our previous study.RESULTS:An increase in the number of patients with candidaemia was observed during 1996 (538) and 1997 (421) compared to 1998-2000 due to P. anomala outbreak. With the control of the outbreak, a substantial decrease in the incidence of candidaemia was observed from 1998 (251 in 1998, 122 in 1999 and 165 in 2000). A higher isolation of non-C. albicans Candida species (89.8%) was observed, with C. tropicalis being the most common (541, 36.1%) agent. No major change in the isolation rate of other non-C. albicans Candida species (C. guilliermondii, C. krusei, C. glabrata and C. parapsilosis) was observed. An emergence of resistance to amphotericin B in 15.4 per cent C. albicans, 8.1 per cent C. tropicalis and 33.3 per cent C. krusei strains was observed. An increase in resistance to ketoconazole (from 0% to 13%) and 5-fluorocytosine (from 1% to 8%) and a decrease to fluconazole (from 13% to 6%) were observed. Resistance to itraconazole was observed in 17 per cent of Candida strains by broth macro-dilution method.INTERPRETATION & CONCLUSION:A change in the isolation of Candida species was observed i.e. in the incidence and isolation of non-C. albicans Candida species. Emergence of resistance to amphotericin B and increase of resistance to most other antifungals are cause for concern.