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V M Katoch

Publications and source records attributed to V M Katoch.

At least 19 recordsLinked to original sources
PubMed2006

Antimycobacterial activity of econazole against multidrug-resistant strains of Mycobacterium tuberculosis.

This study evaluated the antimycobacterial activity of econazole against multidrug-resistant (MDR) strains of Mycobacterium tuberculosis. The minimum inhibitory concentration (MIC(90)) and minimum bactericidal concentration (MBC(>99.99)) against MDR strains were found to be 0.120-0.125 microg/mL and 0.125-0.150 microg/mL, respectively, demonstrating the antimycobacterial potential of econazole.

Antitubercular Agents↗
PubMed2006

Comparative evaluation of Löwenstein-Jensen proportion method, BacT/ALERT 3D system, and enzymatic pyrazinamidase assay for pyrazinamide susceptibility testing of Mycobacterium tuberculosis.

Pyrazinamide (PZA) is an important first-line antituberculosis drug because of its sterilizing activity against semidormant tubercle bacilli. In spite of its very high in vivo activity, its in vitro activity is not apparent unless an acidic environment is available, which makes PZA susceptibility testing difficult by conventional methods. The present study was, therefore, planned to assess the performance of the colorimetric BacT/ALERT 3D system and compare the results with those from conventional tests, i.e., the Löwenstein-Jensen (LJ) proportion method (pH 4.85) and Wayne's pyrazinamidase (PZase) assay, using 107 clinical isolates. The concordance among all of these tests was 89.71% after the first round of testing and reached 92.52% after resolution of the discordant results by retesting. Prolonged incubation of the PZase tube for up to 10 days was found to increase the specificity of the PZase test. The concordances between LJ proportion and BacT/ALERT 3D, LJ proportion and the PZase assay, and BacT/ALERT 3D and the PZase assay were found to be 99.06%, 93.46%, and 92.52%, respectively. Using the LJ results as the gold standard, the sensitivities of BacT/ALERT 3D and the PZase assay were 100 and 82.85%, respectively, while the specificity was 98.61% for both of the tests. The difference between the sensitivities of BacT/ALERT 3D and the PZase assay was significant (P = 0.025). The mean turnaround times for the detection of resistant and susceptible results by BacT/ALERT 3D were 8.04 and 11.32 days, respectively. While the major limitations associated with the PZase assay and the LJ proportion method are lower sensitivity in previously treated patients and a longer time requirement, respectively, the BacT/ALERT 3D system was found to be rapid, highly sensitive, and specific.

Amidohydrolases↗
PubMed2006

Diagnostic value of Elisa serological tests in childhood tuberculosis.

Two separate studies (study I and study II) were conducted to evaluate the efficacy of ELISA serological test for the detection of IgG antibodies against specific glycolipid antigen (PGLTb1) and ESAT 6 antigen of Mycobacterium tuberculosis, respectively. These results were compared with bacteriological tests [Ziehl Neelson (ZN) staining for acid-fast bacilli and culture on Lowenstein Jensen (LJ) medium] and polymerase chain reaction (PCR) targeting IS6110 sequence. Both studies were carried out on children with pulmonary, central nervous system, lymph node, and gastrointestinal tuberculosis along with matching controls (65 cases and 27 controls for study I and 83 cases and 22 controls for study II). Informed consents of their parents or guardians were taken. They were subjected to clinical examination, relevant laboratory investigations, tuberculin test and chest radiograph. Relevant body fluids were subjected to bacteriological tests and PCR. Sera samples were analyzed for antibodies against PGLTbl and ESAT 6 antigen in study I and study II, respectively. ELISA tests showed a significantly higher sensitivity (49% study I; 53%, study II) as compared with LJ medium culture method (15.4%, study I; 28.9% study II) and ZN staining (27.7%, study I; 20.5%, study II) in all patients (p < 0.05). The results were comparable with PCR (40%, study I; 42.2% study II). Specificity of ELISA test was 100% in all the patients except in those with pulmonary disease (92.8%, study I; 84.8%, study II). In view of the convenience, low cost and comparable sensitivity with PCR, these ELISA tests have a promising future in the diagnosis of childhood tuberculosis.

Bacteriological Techniques↗
PubMed2006

Seroprevalence of HIV infection among paediatric tuberculosis patients in Agra, India: a hospital-based study.

In this study which was carried over a period of 2 years, from 2003 to 2004, 270 paediatric patients with active Tuberculosis (TB) disease attending the OPD of S.N. Medical College, Agra were screened for Human Immunodeficiency Virus (HIV)-1/2 antibodies. Of these, 23 were found to be HIV-positive. Seroprevalence of HIV infection among paediatric TB patients in Agra is 8.51% (23/270). The HIV infection was found to be significantly higher, i.e. 82.61% in male children than in female children, i.e. 17.39%. Among the age groups, which were divided into < or =1, 2-5, 6-10 and 11-15 years, maximum cases of HIV-positivity, i.e. 65.22% was observed in the age group, 2-5 years of age. Among the HIV-positive children with TB, 86.75% were of pulmonary and 13.04% were of extra-pulmonary type. Among the vaccinated children, 65.22% were found to be HIV-positive, while 34.78% of the HIV-positive children were not BCG vaccinated. HIV-positive children are more likely to suffer from prolonged fever, weight loss, failure to thrive, developmental delay, stunted growth, cough, anorexia, lethargy, lower respiratory tract infections (LRTI) and hepatosplenomegaly while HIV negative are more likely to suffer from fever, diarrhoea, lymphadenitis, pallor and LRTI. 82.60% (19/23) of these TB patients had a history of positive contact with HIV, i.e. one of the parents was HIV-infected. The mode of transmission of HIV infection among paediatric TB patients was perinatal as revealed during the counselling sessions (pre-test and post-test) of both the parents.

Adolescent↗
PubMed2006

HIV, HBV, HCV, and syphilis co-infections among patients attending the STD clinics of district hospitals in Northern India.

OBJECTIVE: The objective of the study was to assess the risk of co-infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and syphilis among patients attending sexually transmitted disease (STD) clinics, antenatal clinics (ANC) and Ob-Gyn outpatients department (OPD) clinics which were part of the sentinel surveillance program. METHODS: A serological screening was carried out during the period August-November 2002 to assess the risk of infection with HIV-1/2, and co-infection with HBV, HCV, and syphilis among the outpatients attending STD clinics, Ob-Gyn OPD clinics, and ANC of three district hospitals (Agra, Etawah, and Farrukhabad) of Uttar Pradesh state in Northern India. Unlinked and coded serum samples received from 863 patients (635 females and 228 males) were screened by laboratory tests commonly used for laboratory diagnosis of HIV, HBV, HCV, and syphilis. RESULTS: Among the 863 samples serological reactivity was detected for HIV-1/2 in 21 (2.4%), HBV in 25 (2.9%), HCV in nine (1.0%), and syphilis in 47 (5.4%). The incidence of HBV was higher among males than females, i.e. 10/228 (4.4%) versus 15/635 (2.4%). Co-infection was observed for HIV-HBV in two (0.2%), HBV-HCV in one (0.1%), and HIV-syphilis in one (0.1%). None were found to have co-infection with HIV-HCV, HBV-syphilis, and HCV-syphilis. Age, sex, literacy level, occupation, locality, migration, and presence of different sexually transmitted infections did not significantly influence the rate of HIV positives. CONCLUSION: A substantial percentage of the outpatients seen in the clinics of the district hospital in Uttar Pradesh harbor HIV and viral hepatitis infections, which otherwise would remain undiagnosed without serological screening.

Adolescent↗
PubMed2006

Identification of a repetitive sequence belonging to a PPE gene of Mycobacterium tuberculosis and its use in diagnosis of tuberculosis.

A repetitive sequence specific to Mycobacterium tuberculosis was isolated from a lambda gt11 library of M. tuberculosis by DNA-DNA hybridization using genomic DNA of M. tuberculosis as probe followed by subtractive hybridization with a cocktail of other mycobacterial DNA. This led to identification of CD192, a 1291 bp fragment of M. tuberculosis containing repetitive sequences, which produced positive hybridization signals with M. tuberculosis DNA within 30 min. Nucleotide sequencing revealed the presence of several direct and inverted repeats within the 1291 bp fragment that belonged to a PPE family gene (Rv0355) of M. tuberculosis. The use of CD192 as a DNA probe for the identification of M. tuberculosis in culture and clinical samples was investigated. The 1291 bp sequence was present in M. tuberculosis, Mycobacterium bovis and M. bovis BCG, but was not present in many of the other mycobacterial strains tested, including M. tuberculosis H37Ra. More than 300 clinical isolates of M. tuberculosis were probed with CD192, and the presence of the 1291 bp sequence was observed in all the clinical strains, including those lacking IS6110. The sequence displayed RFLP among the clinical isolates. A PCR assay was developed which detected M. tuberculosis with 100% specificity from specimens of sputum, cerebrospinal fluid and pleural effusion from clinically diagnosed cases of tuberculosis.

Bacterial Proteins↗
PubMed2006

Simultaneous ethambutol & isoniazid resistance in clinical isolates of Mycobacterium tuberculosis.

BACKGROUND & OBJECTIVE: There is a need to understand the nature of drug resistance patterns and predictors of emergence of drug resistance in Mycobacterium tuberculosis. There could be common factors/mechanisms for resistance to the drugs, isoniazid and ethambutol, both acting on cell wall. The present study was conducted to analyze the antimycobacterial susceptibility patterns of M. tuberculosis isolates to determine the minimum inhibitory concentrations (MICs) of ethambutol for M. tuberculosis; and to find out possible association of ethambutol resistance with isoniazid resistance. METHODS: A total of 380 M. tuberculosis isolates were tested for their susceptibilities to ethambutol at 2, 4, 6 microg/ml, isoniazid at 1 microg/ml and rifampicin at 64 microg/ml using MIC method. RESULTS: 44.21, 24.73 and 14.21 per cent isolates were resistant to ethambutol at concentrations of 2, 4 and 6 microg/ml respectively. At 6 microg/ml of ethambutol concentration, 85.18 per cent ethambutol resistant isolates were resistant to isoniazid also. At the same ethambutol concentration a fraction of 28.75 per cent isoniazid resistant isolates were ethambutol resistant. INTERPRETATION & CONCLUSION: Ethambutol resistance was accompanied with isoniazid resistance in a large percentage of isolates whereas ethambutol resistance was weakly linked with multidrug resistance. On the other hand, association between isoniazid and ethambutol resistance was weak showing one way linkage.

Antitubercular Agents↗
PubMed2006

Analysis of gene probes and gene amplification techniques for diagnosis and monitoring of treatment in childhood leprosy.

Nucleic acid sequences of Mycobacterium leprae were detected using gene probes hybridizing with targeting ribosomal RNA (16S rRNA), ribosomal DNA (16S rDNA) and gene amplification techniques (PCR) in skin lesion of paediatric leprosy patients and the effect of treatment on the by these methods. Eighty paediatric leprosy patients were included in the study. Most cases (79%) were between 9 and 16 years of age. Cases were divided into three groups according to treatment status, viz. untreated (30), undergoing treatment (30), and at the end of treatment (20). Clinical and slit smear examination for acid fast bacilli (AFB) was performed and nucleic acids were extracted and fractionated from skin biopsies. M. leprae specific 16S rRNA and 16S rDNA was detected by hybridization with gene probes whereas the 36 kDa gene sequence was detected by a gene amplification assay (PCR). The cases were classified as paucibacillary (PB) and multibacillary (MB) by the standard criteria of WHO (1988). Positivity of 16S rRNA in PB cases decreased from 60% in untreated to 10.5% after 4-8 months of treatment whereas for 16S r DNA, it decreased from 50% to 21%, for PCR from 70% to 36.8% for the same specimen, and all became negative at 1 year. Similar trends were seen in MB cases where positivity in smear positive untreated cases decreased from 100% to 56.2% with 16S rRNA and 42.8% with 16S rDNA and PCR, respectively, after 9-12 months of treatment and all became negative at 2 years, except one case which remained positive with PCR. Similar results were observed in smear negative MB cases, 100% positivity detected by 16S r RNA and PCR, 75% detected by 16S rDNA decreased to zero after 9-12 months of therapy. This study suggests the potential usefulness of gene probes targeting 16S rRNA and 16S rDNA and PCR as supportive molecular tools for diagnosis of smear negative evolving MB disease and also monitoring the response to treatment, these observations however, needs to be validated in prospective follow up studies.

Adolescent↗
PubMed2006

Applications of real-time PCR technology to mycobacterial research.

Real-time polymerase chain reaction (PCR) is being used worldwide for various research purposes. In this review we discuss the principles of real-time PCR, different methodologies and chemistries available and their applications in mycobacterial research. This technology allows for the direct detection of PCR product during the exponential phase of the reaction. Being a very powerful, accurate, rapid and sensitive method, this technique holds immense promise for detection of mycobacteria, differentiation of mycobacterial species, quantification of mycobacterial load and detection of drug resistance in mycobacterial infection.

Colony Count, Microbial↗
PubMed2005

Bovine tuberculosis in India: potential basis for zoonosis.

Our laboratory has designed a specific nested-PCR (N-PCR) assay, based on the hupB gene of Mycobacterium tuberculosis (Rv2986c) and Mycobacterium bovis (Mb3010c) as a method to differentiate these closely related species. The present paper deciphers the utility of this assay for identification of pathogenic Mycobacteria in clinical samples. Extra-pulmonary clinical samples obtained from cattle and humans were investigated. Pre-dominance of M. tuberculosis (15.7%) and M. bovis (26.8%) was seen in humans and cattle, respectively. However, more importantly, both mycobacterial pathogens (mixed infection) were identified in a number of samples. In humans 8.7% of the samples and 35.7% in cattle were classified as mixed infection. The detection of mixed infection with the mycobacterial pathogenic duo in humans and bovines denotes the prospect of potential transmission of these pathogens from humans to cattle (zoonosis) and vice versa (reverse zoonosis).

Animals↗
PubMed2005

Animal models of tuberculosis.

It was Robert Koch who recognized the spectrum of pathology of tuberculosis (TB) in different animal species. The examination of clinical specimens from infected humans and animals confirmed the variable patterns of pathological reactions in different species. Guinea pigs are innately susceptible while humans, mice and rabbits show different level of resistance depending upon their genotype. The studies of TB in laboratory animals such as mice, rabbits and guinea pigs have significantly increased our understanding of the aetiology, virulence and pathogenesis of the disease. The introduction of less than five virulent organisms into guinea pigs by the respiratory route can produce lung lesions, bacteraemia and fatal diseases, which helped the extrapolation of results of such experiments to humans. The similarities in the course of clinical infection between guinea pigs and humans allow us to model different forms of TB and to evaluate the protective efficacy of candidate vaccines in such systems. The only limitation of this model, however, is a dearth of immunological reagents that are required for the qualitative and quantitative evaluation of the immune responses, with special reference to cytokines and cell phenotypes. Another limitation is the higher cost of guinea pigs compared with mice. The rabbit is relatively resistant to Mycobacterium tuberculosis, however following infection with virulent Mycobacterium bovis, the rabbit produces pulmonary cavities like humans. The rabbit model, however, is also limited by the lack of the immunological reagents. Mice are the animal of choice for studying the immunology of mycobacterial infections and have contributed much to our current understanding of the roles of various immunological mechanisms of resistance. The resistance of mice to the development of classic TB disease, however, represents a significant disadvantage of the mouse model. Although non-human primates are closely related to humans, owing to high cost and handing difficulties they have not been exploited to a large extent. As all existing animal models fail to mimic the human disease perfectly, efforts should be focused on the development of the non-human primate(s) as the alternative animal model for TB.

Animals↗
PubMed2005

Seroprevalence of HIV infection among tuberculosis patients in Agra, India--a hospital-based study.

In this study which was carried over a period of 4 years, from 2001 to 2004, 600 adult patients with active TB disease attending the OPD of TBDTC, Agra, were screened for HIV-1/2 antibodies. Of these, 26 were found to be HIV-positive. Seroprevalence of HIV infection among adult TB patients in Agra is 4.3% (26/600). The HIV infection was found to be more in females, i.e. 7.95% (7/88) than in males, 3.71% (19/512). HIV-positivity of 5% was observed in the age groups, 15-24 and 25-34 years, i.e. 3/60 and 13/260, respectively. Among HIV-positive TB patients, 4.2% (22/524) were of pulmonary and 5.3% (4/76) were of extra-pulmonary type. A total of 3.04% (6/197) of HIV-positive TB patients were PPD positive and 4.96% (20/403) were PPD negative and bacillary positivity was 4.4% (15/340) and bacillary negativity was 4.2% (11/260). A total of 3.5% (18/515) of TB patients had a history of positive contact, i.e. spouse or one of the family members was HIV-infected. The difference in signs and symptoms among the HIV positive and HIV negative TB patients was found to be statistically significant.

Adolescent↗
PubMed2005

Diagnostic value of in situ Polymerase Chain Reaction in leprosy.

OBJECTIVE: This prospective study was carried out to assess the diagnostic value of in situ Polymerase Chain Reaction in leprosy, particularly in enhancing the histopathological diagnosis. METHOD: Clinical examination of 20 patients (< 16 yr) was done and skin smear for AFB was prepared. Biopsy of lesion site was taken for histopathological examination and in situ PCR testing. RESULTS: The histopathological examination confirmed the clinical diagnosis in 45% cases only; non-specific histopathology was reported in the remaining 55% cases. In situ PCR showed a positivity of 57.1% in early/localized form of leprosy (IIBT) and 61.5% in (BB/BL) group. When compared to histopathology examination, a significant enhancement of 15% in diagnosis was seen. With in situ PCR, the diagnosis could be confirmed in 4/11 (36.3%) cases with non-specific histopathological features, (which is common in early disease) in addition to confirmation of 8/9 (88.8%) histopathologically-confirmed tissue sections. Histopathology and in situ PCR, combined together, confirmed the diagnosis in 13/20 cases (65% of total cases). CONCLUSION: Thus, in situ PCR is an important diagnostic tool especially in early and doubtful cases of leprosy.

Adolescent↗
PubMed2005

Direct detection and identification of Mycobacterium tuberculosis and Mycobacterium bovis in bovine samples by a novel nested PCR assay: correlation with conventional techniques.

Mycobacterium tuberculosis and M. bovis infect animals and humans. Their epidemiology in developed and developing countries differs, owing to differences in the implementation of preventive measures (World Health Organization, 1999). Identification and differentiation of these closely related mycobacterial species would help to determine the source, reservoirs of infection, and disease burden due to diverse mycobacterial pathogens. The utility of the hupB gene (Rv2986c in M. tuberculosis, or Mb3010c in M. bovis) to differentiate M. tuberculosis and M. bovis was evaluated by a PCR-restriction fragment length polymorphism (RFLP) assay with 56 characterized bovine isolates. The degree of concordance between the PCR-RFLP assay and the microbiological characterization was 99.0% (P < 0.001). A nested PCR (N-PCR) assay was developed, replacing the PCR-RFLP assay for direct detection of M. tuberculosis and M. bovis in bovine samples. The N-PCR products of M. tuberculosis and M. bovis corresponded to 116 and 89 bp, respectively. The detection limit of mycobacterial DNA by N-PCR was 50 fg, equivalent to five tubercle bacilli. M. tuberculosis and/or M. bovis was detected in 55.5% (105/189) of the samples by N-PCR, compared to 9.4% (18/189) by culture. The sensitivities of N-PCR and culture were 97.3 and 29.7, respectively, and their specificities were 22.2 and 77.7%, respectively. The percentages of animals or samples identified as infected with M. tuberculosis or M. bovis by N-PCR and culture reflected the clinical categorizations of the cattle (P of <0.05 to <0.01). Mixed infection by N-PCR was detected in 22 animals, whereas by culture mixed infection was detected in 1 animal.

Animals↗
PubMed2005

Seroprevalence of HIV infection among the foreign students at Agra during a fifteen year period (1988-2002).

The present study reports a retrospective analysis of data of HIV testing of foreign students from Sub-Saharan Africa, South-East Asia and Europe, studying as well as staying at Agra, over a period of 15 yr (1988 to 2002). Of the 2653 [2092 (78.85%) were from the Sub-Saharan African countries, 377 (14.21%) from the South-East Asian countries, and 184 (6.93%) from the European countries], foreign students tested for HIV, only 26 were found to be positive for HIV-1/2 antibodies by the ELISA, rapid and Western Blot assays. Out of 26 HIV-positive, 17 males and 7 females were from Sub-Saharan Africa and 2 males were from the European countries. The range of HIV-positivity over a period of 15 yr varied greatly. When the five-year (1988-1992, 1993-1997 and 1998-2002) results were compared, the HIV-seropositivity showed a decline from 1.85, 0.50 to 0.36 per cent in the first, second and third 5 yr slots, respectively. While the data were not representative of all foreign students in India, this reflected the population tested in this centre was not a growing focus of HIV infection in this part of the country.

Adolescent↗
PubMed2005

Seroprevalence of HIV infection among leprosy patients in Agra, India: trends and perspective.

This study compares the results of HIV seroprevalence, which was carried out in two phases, i.e., 1989 to 1993 and 1999 to 2004. Although the number of leprosy patients screened for HIV infection in the second phase is less (2125) as compared to those screened during the first phase (4025), a rise in HIV infection from 0.12% to 0.37% is certainly disturbing since this area appears to be endemic for both the infections. During the study period, the Out Patient department attendance of a few types of leprosy patients like borderline and borderline lepromatous have risen, whereas others like borderline tuberculoid and polar tuberculoid have declined in the second phase as compared to that of the first phase. The trend over a decade suggests that HIV infection is low among the leprosy patients when compared with other risk groups. Follow-up of these patients at an interval of six months, revealed that none of them downgraded into a severe form of leprosy nor developed ARC or AIDS. In this study, it appears that neither infection precipitated the other. The occurrence of downgradation as well as reversal reactions and neuritis (both chronic and acute) was not observed among the leprosy patients. None of them developed erythema nodosum leprosum reactions. Similarly, the HIV-positive leprosy cases did not develop either AIDS related complex (ARC) or full blown case of AIDS.

HIV Infections↗
PubMed2005

Persister studies in leprosy patients after multi-drug treatment.

Cutaneous biopsies were collected from leprosy patients who attended the out-patient department of the Institute for treatment at different intervals, i.e., 12 months, 18 months, 24 months, 36 months, and more after beginning the multi-drug treatment therapy (M.D.T.). The patients belonged to the two drug regimens; (i) standard multibacillary (MB) M.D.T. after 12, 24, and 36 months; or (ii) standard M.D.T. + Minocycline 100 mg once a month (supervised) + Ofloxacin 400 mg once a month supervised for 12 months Biopsies were processed for mouse footpad inoculation and for estimating ATP levels by bioluminescence assay as per established methods. Viable bacilli were observed in 23.5% up to 1 year, 7.1% at 2 years, and in 3.84% at 3 years of M.D.T. by MFP and 29.4%, 10.7%, and 3.84% by ATP assay in the M.D.T. group at the same time period, respectively, but not in M.D.T. + Minocycline + Ofloxacin group after one year. The overall percentage of persisters was 5.55% by MFP and 7.14% by ATP assay up to 3 years of treatment.

Adenosine Triphosphate↗