Meera Sharma

Postgraduate Institute of Medical Education and Research, Chandīgarh, Union Territory of Chandigarh, India

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Publications (104)177.2 Total impact

  • Ajay Kumar, Neelam Taneja, Meera Sharma
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    ABSTRACT: Abstract Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens of worldwide importance, but a shortage of data exists for STEC isolation from India. Therefore, an epidemiological and environmental study that covers a large geographic area in north India was conducted. Ruminant stool samples (n=650) were collected from 59 dairies. Meat samples (n=450) were collected from local abattoirs and the main slaughterhouse of the region. Additionally, 600 human cases of diarrhea and hemolytic uremic syndrome were screened for STEC. Isolates were characterized for the virulence gene profiles and for the serogroups and were submitted to molecular typing by the multilocus variable-number tandem-repeat analysis (MLVA). Overall, 12.3% of animal stool samples and 6.3% of mutton samples (n=160) were positive for STEC. Additionally, STEC were isolated from 1.7% and 1.6% of watery (n=290) and bloody (n=310) stool specimens, respectively. Animal stool isolates were significantly more prevalent in hilly areas (p<0.05) than in plain areas. Polymerase chain reaction demonstrated the presence of stx1, stx2, hly, espP, saa, toxB, and iha genes in 117 (83.5%), 94 (67.1%), 77 (55%), 33 (23%), 62 (44.2%), 29 (20.7%), and 51 (36%) of the isolates, respectively. Five new serogroups (O55, O33, O173, O165, and O136) are being reported for the first time from India. Four isolates from serogroup O103 were found in mutton and stool specimens of cattle and humans (n=160). One isolate from serogroup O104 was isolated from a mutton sample. MLVA suggested the potential transmission of STEC from contaminated meat and bovine sources. This study confirms the frequent contamination of mutton samples (24%), whereas chicken and pork samples were negative for STEC. This study demonstrates the presence of STEC that carry a large repertoire of virulence genes and the potential transmission of STEC from contaminated mutton and animal stools in north India.
    Foodborne Pathogens and Disease 05/2014; · 2.28 Impact Factor
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    ABSTRACT: Resistance to third generation cephalosporins in non- typhoidal Salmonella (NTS) is emerging worldwide. We report the occurrence of ESBL phenotypes in 53.4% of NTS isolated over a period of nine years from gastroenteritis cases. ESBL and AmpC co-production was observed in 21% of the isolates. Occurrence of blaCTXM-15 and blaCMY-2 resistance genes was observed in 11.6% and 37% of the isolates respectively. Overall, S. Senftenberg was the predominant serovar carrying blaCTXM-15 and blaCMY-2 resistance genes. We are reporting for the first time from India, one isolate each of S. Thompson, S. Infantis and S. Newport, carrying blaCTXM-15 gene. We also report a case of gastroenteritis due to S. Thompson, for the first time from India.
    Journal of Medical Microbiology 10/2013; · 2.30 Impact Factor
  • The Indian Journal of Medical Research 07/2013; 138(1):143-6. · 2.06 Impact Factor
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    ABSTRACT: Loop-mediated isothermal amplification (LAMP) assay has come forward as a rapid, cost-effective molecular technique for diagnosis of tuberculosis (TB) in developing countries. This study evaluated Mycobacterium tuberculosis-specific in-house LAMP assay targeting 16s rRNA and compared it with other conventional tests and nucleic acid amplification assay (IS6110 PCR). A total of 133 sputum specimens (103 from suspected pulmonary TB cases and 30 from non-TB controls) were subjected to conventional tests, IS6110 PCR and 16s rRNA LAMP assay. Of the 103 patients, the maximum number of cases were found to be positive by LAMP assay, that is, in 87 (84.5%) patients, followed by culture positive in 78 (75.7%), IS6110 PCR in 74 (71.8%), and smear positive in 70 (67.9%) patients. Of the 83 smear positive and/or culture positive cases, LAMP detected 77 (92.77%) cases, and was found to be superior to IS6110 PCR, which could detect 69 (83.1%) cases; a concordance of 0.6 was obtained between the two tests using kappa statistics. Overall, LAMP was simple and efficacious for early diagnosis of smear positive, culture positive cases as well as for confirmation of smear negative, culture negative cases, and was found to be superior to IS6110 PCR.
    Journal of Clinical Laboratory Analysis 07/2013; 27(4):272-6. · 1.36 Impact Factor
  • Clinical Microbiology Newsletter 06/2013; 35(11):92–93.
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    ABSTRACT: The clinical features of abdominal tuberculosis (TB) are non-specific and establishing a diagnosis remains a challenge. A delay in diagnosis is likely to increase the morbidity in these patients. We developed a multiplex polymerase chain reaction (PCR) using 16SrRNA, IS6110, and devR, and evaluated it in comparison with other conventional tests in clinical suspects of abdominal TB. A total of 183 patients with clinical suspicion of abdominal TB (96 patients with intestinal TB and 87 with peritoneal TB) were enrolled for the study. Endoscopic or intraoperative biopsies were collected from patients suspected of intestinal TB and ascitic fluid was collected from patients with a suspicion of peritoneal TB. Of the intestinal tuberculosis group, there were 40 confirmed cases and 56 controls, while of the peritoneal tuberculosis group there were 37 confirmed cases and 50 controls. Multiplex PCR showed a high sensitivity and specificity in both the intestinal TB and peritoneal TB groups. When combined with histopathology, multiplex PCR could detect 97.5% of all the cases in the intestinal tuberculosis group, while in combination adenosine deaminase levels (ADA) in cases of peritoneal tuberculosis it increased the specificity of diagnosis of peritoneal tuberculosis to 95%. In combination with histopathology in suspected intestinal TB cases, and ADA testing in suspected peritoneal TB cases, it can be used as a highly sensitive, specific, and rapid diagnostic tool with the ability to supplement the limitations of other diagnostic modalities.
    Diagnostic microbiology and infectious disease 05/2013; 76(1):51-5. · 2.45 Impact Factor
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    ABSTRACT: Rapid and specific diagnosis of gastrointestinal tuberculosis (GITB) is of utmost importance. To evaluate Multiplex PCR (MPCR) using MPB64 and IS6110 primers specific for M. tuberculosis for rapid diagnosis of GITB. MPCR was performed on colonoscopy biopsy specimens on 11 GITB confirmed (culture/AFB/histopathology was positive), 29 GITB suspected and 30 Non GITB (control group) patients. MPB64 PCR had sensitivity and specificity of 90% and 100% for confirmed GITB cases. In 29 clinically diagnosed but unconfirmed GITB cases, MPCR was positive in 72.41%. MPCR was negative in all control group patients. The overall sensitivity and specificity of microscopy, culture, histopathology and MPCR was 5%, 2% 20% and 77.5% and 100%, 100%, 100% and 100% respectively. MPCR has good sensitivity and specificity in diagnosing gastrointestinal tuberculosis.
    Journal of global infectious diseases 04/2013; 5(2):49-53.
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    ABSTRACT: BACKGROUND: Multidrug resistant (MDR) and extensively-drug resistant (XDR) tuberculosis (TB) are a serious threat to the national TB control programs of developing countries, and the situation is further worsened by the human immunodeficiency virus (HIV) pandemic. The literature regarding MDR/XDR-TB is, however, scanty from most parts of India. We carried out this study to assess the prevalence of MDR/XDR-TB in new and previously treated cases of pulmonary TB and in HIV seropositive and seronegative patients. METHODS: Sputum and blood specimens were obtained from 2100 patients suspected of pulmonary tuberculosis and subjected to sputum microscopy and culture for TB, and HIV serology at our tertiary care centre in north India. The culture positive Mycobacterium tuberculosis isolates were subjected to drug susceptibility testing (DST) for first line anti-tuberculosis drugs, and the MDR isolates were further subjected to second line DST. Various parameters of the patients' were analyzed viz. clinical presentation, radiology, previous treatment history, demographic and socioeconomic data and microbiology results. RESULTS: Of the 2100 patients, sputum specimens of 256 were smear positive for acid-fast bacilli (AFB), 271 (12.9%) grew Mycobacterium spp., and M. tuberculosis was isolated in 219 (10.42%). Of the 219 patients infected with M. tuberculosis, 20.1% (44/219) were found to be seropositive for HIV. Overall, MDR-TB was observed in 17.4% (39/219) isolates. There were 121 newly diagnosed and 98 previously treated patients, of which MDR-TB was found to be associated with 9.9% (12/121) and 27.6% (27/98) cases respectively. There was significantly higher association of MDR-TB (12/44, 27.3%) with HIV seropositive patients as compared to HIV seronegative patients (27/175, 15.4%) after controlling previous treatment status, age, and sex (odd's ratio, 2.3 [95% CI, 1.000-5.350]; p-value, 0.05). No XDR-TB was found among the MDR-TB isolates. CONCLUSION: The present study demonstrated a high prevalence of drug resistance amongst pulmonary TB isolates of M. tuberculosis from north India as compared to the WHO estimates for India in 2010, though this could possibly be attributed to the clustering of more serious or referred cases at our tertiary care centre. The prevalence of MDR-TB in HIV seropositive patients was significantly higher than seronegative individuals. The study emphasizes the need to monitor the trends of drug resistance in TB in various populations in order to timely implement appropriate interventions to curb the menace of MDR-TB.
    BMC Infectious Diseases 03/2013; 13(1):137. · 3.03 Impact Factor
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    ABSTRACT: Central nervous system (CNS) infections caused by non tuberculosis Mycobacteria (NTM) are believed to be rare. In developing countries, these are also likely to be missed either due to lack of awareness or lack of facilities to diagnose them. We are reporting M. avium CNS infections in 13.6% (12/114) of the HIV patients visiting our tertiary care centre in North India. This is one of the largest series of M. avium CNS infection from a developing country. Our experience highlights the need to look for M. avium infection in HIV patients presenting with CNS infection and shows that molecular techniques like PCR are a beneficial tool in diagnosing them.
    AIDS research and human retroviruses 02/2013; · 2.18 Impact Factor
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    ABSTRACT: The objective of this study was to report the use of multi-targeted polymerase chain reaction (PCR) in the diagnosis of presumed tubercular uveitis. Multi-targeted PCR using three targets specific for Mycobacterium tuberculosis, i.e., IS6110, MPB64, and protein b, was performed on intraocular fluid samples of 25 subjects. Nine had presumed tubercular uveitis, six had intraocular inflammation secondary to a nontubercular etiology (disease controls), and ten had no evidence of intraocular inflammation (normal controls). As described previously, response to antitubercular therapy was considered as the gold standard. Multi-targeted PCR was positive in seven out of nine patients with presumed tubercular uveitis and negative in all normal and disease controls. The sensitivity and specificity were 77.77% and 100%, respectively. For the diagnosis of presumed tubercular uveitis, multi-targeted PCR had a positive predictive value of 100% and a negative predictive value of 88.88%. Multi-targeted PCR can be a valuable tool for diagnosing presumed tubercular uveitis.
    Journal of ophthalmic inflammation and infection. 01/2013; 3(1):25.
  • Journal of Global Antimicrobial Resistance. 01/2013;
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    ABSTRACT: Bacterial flora in burn patients undergoes change over 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. Since no studies are available from India that have studied sequential emergence of different microorganisms in burn wound, present study was carried out to study evolution of bacterial flora in burn wounds and its correlation with invasive wound infection. Environmental sampling was also carried out for possible sources of infection. Patients with 20-70% of total burn surface were enrolled and followed up for entire duration of stay. Clinical & treatment details were noted. Surface wound swabs were collected on first, third, seventh, tenth and fourteenth day post admission. Environmental sampling was done every three months. Of 215 wound swabs collected from 71 patients, 72 were sterile and 143 yielded 214 isolates. Colonization rates were 33% on first day, 94% on 7th day and 100% by 14th day. 42% swabs grew gram negative bacteria. Overall Staphylococcus aureus was the predominant isolate (45%) followed by Pseudomonas aeruginosa (13.9%), beta hemolytic Streptococci (9.4%). Maximum invasive infections were seen at the seventh day. A high level of environmental contamination was seen with S. aureus, a substantial portion being MRSA. Better control of environmental contamination and disinfection along with rigorous hand washing and barrier precautions are recommended to prevent infection of wounds.
    International journal of burns and trauma. 01/2013; 3(2):102-7.
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    ABSTRACT: Mycoplasma genitalium is a member of genital mycoplasmas, which is emerging as an important causative agent of sexually transmitted infections both in males and females. The advent of polymerase chain reaction and other molecular methods have made studies on M. genitalium more feasible, which is otherwise a difficult organism to isolate. Besides Chlamydia trachomatis, M. genitalium is now an important and established cause of non gonococcal urethritis (NGU) in men, more so in persistent and recurrent NGU. Multiple studies have also shown a positive association of M. genitalium with mucopurulent cervicitis and vaginal discharge in females as well. The evidences for M. genitalium pelvic inflammatory diseases and infertility are quite convincing and indicate that this organism has potential to cause ascending infection. Lack of clear association with M. genitalium has been reported for bacterial vaginosis and adverse pregnancy outcomes. Diagnosis of M. genitalium infections is performed exclusively using nucleic acid amplification tests (NAATs), owing to poor or slow growth of bacterium in culture. Although there are no guidelines available regarding treatment, macrolide group of antimicrobials appear to be more effective than tetracyclines. The present review provides an overview of the epidemiology, pathogenesis, clinical presentation and management of sexually transmitted infections due to M. genitalium.
    The Indian Journal of Medical Research 12/2012; 136(6):942-55. · 2.06 Impact Factor
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    ABSTRACT: Background & objectives: Several outbreaks of cholera have been reported in Chandigarh region during a span of seven years from 2002-2008. The genetic characteristics of Vibrio cholerae isolates obtained during these outbreaks have not been adequately studied. The aim of this study was to do molecular typing of V. cholerae isolated from the sporadic and outbreak cases by pulsed-field gel electrophoresis (PFGE), Rep-PCR and ribotyping. Methods: Fifty representative isolates of V. cholerae from outbreak as well as sporadic cases were subjected to molecular typing by PFGE, 173 isolates (163 clinical and 10 environmental) were typed by rep-PCR and ribotyping. Ribotyping was done by determination of rRNA restriction pattern of BglI restriction digestion and hybridization with 7.2 kb rRNA probe of pKK3535 plasmid using DIG DNA labelling and detection kit. Universal VC1 primer was used for rep-PCR. Results: PFGE generated 15 pulsotypes, of which four matched the published pulsotypes and there were 11 new pulsotypes. PFGE was the most discriminatory method that could differentiate between isolates belonging to single ribotype. Pulsotype P1 corresponding to known pulsotype H1 was the major pulsotype till 2003. Pulsotype P3 corresponding to known pulsotype L emerged in 2004. The 2007 outbreaks in Punjab and Haryana were caused by P5 though P1 and P3 were isolated from the sporadic cases from the same region. The 2008 outbreak was caused by pulsotypes P6 and P7. Ribotype IV was the most predominant followed by RIII. This ribotype was not isolated after 2003 and ribotype IV became the most predominant 2004 onwards. Of the two unknown ribotypes (UNI and UN2), UNI was more common (27 isolates). Rep-PCR was the least discriminatory and divided all clinical isolates into four major profiles. The dendrogram analysis of PFGE revealed similarity of some clinical isolates with environmental isolates indicating the genetic relatedness. Interpretation & conclusion: Our findings showed that Rep-PCR was least discriminatory method. Ribotyping was a reliable and reproducible method. Ribotype IV was predominant ribotype followed by RIII. A total of 15 pulsotypes were generated and 11 of these were not reported earlier. Genetic relatedness was shown by clinical and environmental isolates which needs to be confirmed in future studies.
    The Indian Journal of Medical Research 10/2012; 136(4):656-63. · 2.06 Impact Factor
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    The Brazilian journal of infectious diseases: an official publication of the Brazilian Society of Infectious Diseases 09/2012; 16(5):493-4. · 1.04 Impact Factor
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    ABSTRACT: Restriction fragment length polymorphism (RFLP) based on IS6110 is considered the gold standard for Mycobacterium tuberculosis molecular typing. It is useful to discriminate among M. tuberculosis strains, investigate outbreaks and distinguish between reactivation and re-infection. We studied polymorphisms among M. tuberculosis isolates from northern India using RFLP to determine the presence of a correlation between IS6110 based fingerprints and drug resistance and to look for relapse and transmission among patients and their contacts. RFLP patterns of PvuII digested genomic DNA of 100 M. tuberculosis isolates were analyzed using southern blotting with a 245 bp IS6110 probe. Drug sensitivity testing (DST) was conducted for rifampicin (40 microg/ml), isoniazid (1 microg/ml), ethambutol (2 microg/ml) and streptomycin (4 microg/ml) using the proportion method. A high degree of polymorphism was seen among the M. tuberculosis isolates and the number of IS6110 copies varied from 0 to 14, with a predominance of isolates with 11 bands. Seventy-five isolates had a high number of bands, 9 had an intermediate number, 6 isolates had a low number and 10 isolates had no bands. No correlation between IS6110 band numbers and RFLP banding patterns was found with drug resistance or for any particular geographical area, although clustering was seen amongst MDR-TB cases. No cases of relapses or transmissions were seen.
    The Southeast Asian journal of tropical medicine and public health 09/2012; 43(5):1161-8. · 0.61 Impact Factor
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    ABSTRACT: Nosocomial food outbreaks due to infected food handlers is primarily due to inadequate knowledge and faulty practices of food handlers during diarrhoeal episodes. The aim of this study was to assess: 1) prevalence of enteropathogen infection among food handlers working in our hospital during 2007 to 2011 and 2) adequacy of precautions taken by them during gastroenteritis episodes. Stool samples submitted by food handlers during 2007 to 2011 were examined for the presence of enteropathogens by standard methodology. For the second part of the study, a questionnaire regarding practices during episodes of diarrhoea in food handlers or their family members was handed out to willing participants. During the years 2007, 2008, 2010 and 2011 respectively, 3.9%, 9.8%, 5.1% and 9.4% food handlers were found infected with enteropathogens. The most common parasite detected was Entamoeba histolytica. Bacterial enteropathogens prevalence was very low during these years. There was high awareness (78.8%) among the food handlers regarding routine testing of faeces. Only 64.7% knew that it was important to report for purpose of treatment and leave. While 9.4% had suffered from diarrhoeal episodes in between intervals of annual microbiological testing, only 4.7% took appropriate treatment and availed medical leave. A regular training programme on food safety should be established and emphasis should be laid on mandatory reporting and stool testing of kitchen personnel as well as abstaining from work till they are medically fit.
    The Journal of communicable diseases. 09/2012; 44(3):139-44.
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    ABSTRACT: M. tuberculosis (MTB) is an important cause of morbidity and mortality in India. However, in recent years, the significance of nontuberculous mycobacteria (NTM) has also increased after the onset of HIV/ AIDS epidemic. Meningitis due to M. avium is rare, but often responsible for fatal outcome as high as 60% of cases. Literature regarding the true prevalence of dual infection with MTB and M. avium is scanty and most of these cases are treated as drug resistant cases. We report here two cases of dual infection due to MTB and M. avium which had a fatal outcome. The paper highlights an urgent need for use of multiplex polymerase chain reaction in routine diagnostic laboratories. This would help in the diagnosis of co-infections due to NTMs, especially M. avium with MTB, in patients with HIV/AIDS and therefore assist in better patient management and outcome of the disease.
    Journal of Medical Microbiology 08/2012; · 2.30 Impact Factor
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    ABSTRACT: AmpC beta lactamase producing Gram-negative bacteria have emerged worldwide. It is important to distinguish plasmid mediated AmpC β lactamases from chromosomally mediated enzymes for surveillance, epidemiology and hospital infection control as plasmid mediated genes can spread to other organisms. Occurrence of blaCMY-1 AmpC β-lactamase, a plasmid mediated cephamycinase was studied in 100 consecutive isolates of Escherichia coli from cases of complicated urinary tract infection (UTI). Screening for AmpC production was done by modified Hodge test, three dimensional test and AmpC disk test. All isolates showing a positive result by 2 out of 3 tests were then tested for blaCMY-1 gene by PCR. Fifty nine isolates were positive for AmpC β lactamase production, 56.6 per cent were positive by PCR. Eight out of 13 isolates which were negative by EDTA disk method were positive by PCR, whereas none of the isolates negative by 3D and modified Hodge test was positive by PCR. Among admitted patients urinary catheterisation was the major risk factor followed by obstructive uropathy, three patients developed urosepsis. High occurrence of blaCMY-1 AmpC β-lactamase warrants health care workers to endorse good hospital practices.
    The Indian Journal of Medical Research 08/2012; 136(2):289-91. · 2.06 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate and compare practically achieved disinfection efficacy of some locally available disinfectants on surfaces and infectious microbiological hospital waste. Seven disinfectants were tested at concentrations recommended by manufacturers on rough and smooth surfaces that were contaminated experimentally by locally circulating isolates of methicillin-resistant Staphylococcus aureus, multidrug-resistant Acinetobacter baumannii, Klebsiella pneumoniae, Enterobacter aerogenes, Pseudomonas aeruginosa strains, standard isolate of Salmonella typhi and Candida albicans. Reduction in microbial counts before and after surface disinfection was expressed as log reduction. A very heavy microbial waste load was simulated by immersing culture plates with heavy microbial growth in disinfectants. Daily, a sample of disinfectant was taken and subjected to in-use test. The highest average log reduction of test microbes on the rough surface was given by DesNet (5.05) and Bacillocid special (5.02). A comparable average log reduction of test microbes on a smooth steel surface was noted (5.68, 5.67, 5.50) for Lysol, Bacillocid sp. and DesNet, respectively. In the discard jars, Bacillocid special worked satisfactorily for 4 days, DesNet for 3 days and Hi-giene Germitol for 1 day. The remainder of the disinfectants failed in the in-use test on Day 1. Phenolics, although widely used in our settings, may not be as good surface disinfectants as newer formulations like DesNet and Bacillocid special. Newer quaternary ammonium compounds and aldehyde formulations were found to be the best disinfectants for disinfection of heavy contamination.
    Indian Journal of Critical Care Medicine 07/2012; 16(3):123-9.

Publication Stats

668 Citations
177.20 Total Impact Points


  • 2003–2012
    • Postgraduate Institute of Medical Education and Research
      • Department of Medical Microbiology
      Chandīgarh, Union Territory of Chandigarh, India
  • 2002–2012
    • Biomedical Informatics Centre
      Chandigarh, Chandīgarh, India
  • 2007
    • Panjab University
      • Department of Biotechnology
      Chandīgarh, Union Territory of Chandigarh, India
  • 2005
    • Wayne State University
      • School of Medicine
      Detroit, MI, United States