Dr Rama Chaudhry
Department of Microbiology
All India Institute of Medical Sciences., New Delhi.
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Dr. Chaudhry has done her MBBS from LHMC and MD from AIIMS, New Delhi. Having started her career in the field of academics, as a Lecturer at UCMS, and present working as an Additional Professor in the Microbiology Department at AIIMS. Now, having attained an experience of over 15 years in the field of academics and medical-research , to her credit, she has over a hundred of research papers published in journals of both national and international repute. Besides many honours and memberships from various scientific disciplines, as an invited guest speaker, she has been among the research advisory and project review committees of national funding sectors such as the DBT and ICMR.
Areas of research interest
- Anaerobic bacteriology
Dr. Chaudhry is in-charge of anaerobic-lab in the department of Microbiology, which serves as a referral lab for several teaching and non-teaching hospitals in the country. This lab is responsible for its diagnostics catering via its routine culture and drug susceptibility testings, supply / identification of anaerobic strains on demand, and also provides hands on training programs for summer-trainees. The active research in this area involves studies pertaining molecular characterisation and diagnostics for anaerobic-pathogens w.r.t. C. botulinum and C. difficile. An outbreak of suspected C. butyricum botulism in India was investigated (Emerg. Infect. Dis., 1998; 4(3): 506-7) by applying these recent techniques. In a preliminary study of C. difficile infection at AIIMS, a tertiary care hospital, the prevalence of infection has been found to be 15%. A PCR-based diagnostic assay for these fastidious anaerobes is underway.
In an ICMR-funded project, comparative evaluation of available diagnostic tests for M. pneumoniae were carried out. Since most of the kits are too expensive and usually imported, an effort was made to develop our own indigenous tests by standardising ELISA using self prepared antigens (a 170 kD-virulence protein-P1) while comparing it with other techniques.
The Mycoplasma lab of o ur department is now equipped for the M. pneumoniae diagnosis by culture, antigen detection and PCR. Recently work has been initiated to screen Mycoplasma specific various proteins in order to study their super-antigenic activities and possible roles in autoimmune disorders (DST-project). Towards this, various protein-fractions have been purified and we are currently in process of developing a T-cell proliferation assay
to study immune responses specific to these proteins. In another research-project, cloning and expression studies of immunodominant portions of P1-protein (P1-gene) in M. pneumoniae is being undertaken.
Research interests under this head involves studies on molecular diagnostics, epidemiology & drug resistance mechanisms, in association with enteric illnesses. A multiplex PCR-based diagnostic-test have been indigenously developed using a Salmonella-genus specific multiple primer-pairs chosen within conserved regions of flagellin gene-sequence, for the simultaneous detection of common serovars (S. Typhi / Paratyphi-A) implicated in enteric fever in our region. Molecular-typing of different strains of Salmonella obtained from Delhi
and other parts of our country have shown subtle differences in DNA-profiles generated by PFGE suggestive of a considerable genetic variations in genomes of S. typhi organisms in this region. Using a self developed salmonella insertion element (IS200-) specific DNA-probe, the hybridised genomic-restriction patterns revealed subtle differences among the clinical isolates from multidrug resistant and sensitive groups, having unique profiles assigned to
resistant isolates. The molecular typing by PFGE and IS200 have been very useful in tracing
the source (index case) while investigating an outbreak of paratyphoid fever which occurred in a residential colony in New Delhi, during July- September 1996 (Trop. Gastroenterol. Jul-Sep’2001). In cases where patients didn’t respond to ciprofloxacin-therapy, both S. Typhi and Paratyphi A strains were shown to have attained higher MICs (0.125 to 2.0 ug/ml) by E-Test (AB- Biodisc) technique, suggesting recent emergence of resistance to this vital drug. Molecular features and analysis of these atypical strains are currently being resolved.
Leptospirosis has been in research-focus due its recent reemergence in north India. As our lab routine, culture-isolation and maintenance of pathogenic human Leptospiral serovars are done in EMJH-medium.
Leptospires viewed from standard-cultures
Sero-diagnosis of clinically suspected blood specimens are usually done by ELISA and Dri-dot assays. Currently an ELISA based antigen detection system along with standardisation of a PCR-based assay for the specific detection of pathogenic serovars of Leptospires in this region, is the theme of an ongoing DBT-project.
- Foodborne pathogens
As a result of a ‘DBT-task-force’ constituted by the ministry of Science and technology, Gov. of India, through a departmental collaborative project from DBT, the molecular approaches in the detection of various foodborne microbial pathogens comprises the current area of research focus. Foodborne pathogens such as Clostridium and Salmonella have been extensively studied on molecular basis with the development of PCR-based assay for these important microbial foodborne-pathogens.