Nocardia bacteraemia in an HIV-positive patient - a case report

Nocardiosis has been recognized in recent times as an unusual opportunistic infection associated with HIV. Bacteraemia due to this pathogen is even rarer and only few cases have been reported in the literature. We report here a case of pulmonary nocardiosis with bactcracmia, which was initially diagnosed as pulmonary tuberculosis. A high index of suspicion is required to diagnose this infection as the clinical presentation and radiographic features mimic pulmonary tuberculosis

Vancomycin for controlling contamination of selective Kirchner’s liquid medium in the culture of gastric lavage for tubercle bacilli

Gastric lavage (GL) was collected for culture of tubercle bacilli from children too young to expectorate sputum. The selective Kirchner’s liquid medium (SKLM), routinely used as one of the media for culture of all extrapulmonary specimens, was found to often get contaminated when cultured with GL. We have shown that vancomycin at a concentration of 10 mg/l successfully reduced the contamination from about 60 to 20 per cent, and enhanced the Isolation rate of tubercle bacilli from 3 to 6 per cent. Decontamination of the liquid culture before subculture on solid medium also helped to reduce the contamination rate. Vancomycin was found to be an effective selective drug for use In the Kirchner’s liquid medium for culture of tubercle bacilli

Early results from indirect drug susceptibility test for tubercle bacilli

The indirect susceptibility test results on L-J medium for tubercle bacilli against streptomycin, isoniazid and rifampicin were read at the end of 2 wk and compared with the results at 4 wk. It was found that drug resistance could be correctly predicted in over 70 per cent of cultures including multi-drug resistant tuberculosis (MDR TB) strains at the end of 2 wk. The susceptibility to para-nitrobenzoic acid (PNB) read at 2 wk was able to distinguish non-tuberculous mycobacteria from Mycobacterium tuberculosis cultures. The early detection of resistance by this procedure requires only minimum inputs, and can benefit the majority of patients harbouring drug resistant tubercle bacilli

IgG antibodies against antigens of various mycobactrial species in children and in pre & Post BCG young adults

IgG antibodies against antigens of various mycobacteria were estimated by ELISA in serum samples collected (a) from 36 children (mean age 4.4 years) belonging to Koppur village in the south Indian BCG Trial area, (b) before and after BCG vaccination of 13 young individuals (mean age 16.5 years) belonging to Trivellore in the same area and (c) before and after BCG vaccination from 20 young British subjects (mean age 14.5 years). In the Koppur children, the antibody levels were highest against M. scrofulaceum and M. avium and lowest against M. bovis and M. tuberculosis H37Rv. In these children, there was no correlation between antibody levels and tuberculin reactivity. In the Trivellore subjects, antibody levels were highest against M. bovis BCG and M. gordonae, and lowest against PPD RT22 and M. terrae and none of the differences in the antibody levels against individual antigens between the preand post-BCG serum samples was statistically Significant (p >.05). The British subjects had the highest levels against M. tuberculosis 7219 while the lowest levels were against M. kansasii and M. tuberculosis 51; after BCG v a c c i n a t i o n t h e a n t i b o d y l e v e l s w e r e selectively increased against M. tuberculosis 7219, M. flavescens and M. gordornae (p <0.05)

Seroprevalence of human immunodeficiency virus (HIV) infection among tuberculosis patients in Tamil Nadu

Background & objectives: The dual epidemic of HIV and tuberculosis is a cause for concern in those countries where these two infections are prevalent in epidemic proportions. We undertook a survey at two sites in North Arcot district of Tamil Nadu in 1992-1993, to know the seroprevalence of HIV infection among tuberculosis patients. The objective of this study was to re-examine the prevalence of HIV infection among tuberculosis patients in a repeat survey. Methods: The study was undertaken in four centres: District Tuberculosis Centre (DTC), Vellore, Tuberculosis Sanatorium, Pennathur (Vellore), District TB Centre (DTC), Kancheepuram and the Government Thiruvotteswarar Tuberculosis Hospital (GTTH), Chennai in the northern part of Tamil Nadu during 1997-1998. A total of 2361 newly diagnosed TB patients were registered in this study. HIV serology after pre-test counseling was done along with sputum examination for acid-fast bacillus by smear and culture for mycobacteria for all patients. Results: The overall HIV seroprevalence among TB patients was 4.7 per cent. The highest HIV seropositivity rate was found among patients aged 30-39 yr (10.6%). HIV seroprevalence showed a wide variation among the different centres ranging from 0.6. per cent in DTC, Kancheepuram to 9.4 per cent in Pennathur Sanatorium, Vellore. Sputum smear positivity was 88 per cent among the HIV-negative and 83 per cent among HIV-positive tuberculosis patients. Interpretation & conclusion: HIV infection is on the rise among TB patients in Tamil Nadu. Acid-fast smear microscopy is adequate for the diagnosis of pulmonary tuberculosis, and drug resistance among HIV positive patients is not a major problem at this point of time; hence antituberculosis regimens recommended by the Revised National Tuberculosis Control Program (RNTCP) can be used to treat HIV positive patients with tuberculosis

A direct rifampicin sensitivity test for tubercle bacilli

A direct sensitivity test for rifampicin has been standardised for early detection of resistance for the mycobacterium tuberculosis smear positive sputum samples. Indirect sensitivity tests set up from primary cultures of the same samples served as controls. The direct test showed 95 per cent agreement with the standard indirect test and as such 74 per cent and 90 per cent of the resistant strains were detected by the fourth week and fifth week, respectively, with an overall gain of 4-5 wks time. Resistance could be detected earlier for multibacillary specimens. This direct sensitivity test on Lowenstein Jensen (LJ) medium offers a feasible alternative for laboratories which lack facilities to perform drug susceptibility tests by the rapid but sophisticated and costly BACTEC method. The method is simple to perform, economic, reliable and amenable to confirmation by the indirect test, if needed

Restriction fragment length polymorphism of Mycobacterium tuberculosis strains from various regions of India, using direct repeat probe

Intraspecies differentiation was studied on 68 M. tuberculosis strains obtained from 6 states of India by restriction fragment length polymorphism (RFLP) using a direct repeat probe (DR probe) hybridised with Alu I digest of DNA. Most strains showed polymorphism based patterns that comprised between 2 to 7 bands and were grouped into 26 RFLP types. Of the 11 strains tested from Amritsar, 8 were RFLP type 5; the remaining 3 were of type 11 and were exclusively confined to this region. The strains from other regions were more heterogeneous. We confirm that DR-associated RFLP can be an excellent tool for the differentiation of M. tuberculosis strains. Depending on their geographical origin, these strains can be differentiated to a large extent by DR fingerprinting

Identification & differentiation of Mycobacterium avium & M. intracellulare by PCR- RFLP assay using the groES gene

Background & objectives: We report a new polymerase chain reaction (PCR) – restriction fragment length polymorphism (RFLP) assay using mycobacterial groES as a target to identify Mycobacterium avium and M. intracellulare in clinical samples. Methods: The assay was standardized using M. avium and M. intracellulare standard strains obtained from ATCC and was tested with 45 M. avium-M. intracellulare complex (MAC) clinical isolates (Of which 31 were from HIV+ individuals). The standard and clinical strains were typed with HPLC based mycolic acid fingerprinting. Results: Three polymorphisms (BamHI, BstNI and HgaI) were identified for inter-species differentiation among standard strains; of which, only HgaI was found to be useful in clinical isolates. Of the 45 isolates, 25 were M. avium and 20 were M. intracelluare. MAC isolates, which could not be differentiated by HPLC analysis, were also typed by this method. Interpretation & conclusions: The use of mycobacterial groES as a PCR-RFLP target for M. avium and M. intracellulare is a simple and rapid method that can complement HPLC in their differentiation

Bacteriology of Acute Respiratory Infections in Children

Bacteriological investigations were carried out on 151 children (80 males and 71 females) suffering from acute respiratory infections (ARI) to And out bacteria associated with ARI. Fifty one children presenting with upper respiratory infections (URI) and 100 with lower respiratory infections (LRI) seen at the outpatient department of the Institute of Child Health and Hospital for Children, Madras, were included in this study. In all, 56% of the children yielded any one or a mixture of bacteria that could be potential or probable pathogens of ARI. Nonfermenting gram negative bacilli (NFGNB) were the predominant organisms isolated (27%) followed by non-typable ampicillin resistant Haemophilus influenzae (13%) and b. haemolytic streptococci groups C and G (11%). The other bacteria isolated in this study were Klebsiella pneumoniae (7%), Streptococcus pneumoniae (3%), Neisseria sps. pure (3%) and Staphylococcus aureus (1%). The isolation rate of NFGNB was maximum (47%) when the duration of illness exceeded 7 days. Mixed infections of potential or probable pathogens were observed in 11 patients which included NFGNB + K. pneumoniae (2); H. influenzae + NFGNB (2); b- haemolytic streptococci + H. influenzae (2); b- haemolytic streptococci + K. pneumoniae (1) ; S. aureus + K. pneumoniae (1) ; Neisseria sp. + K. pneumoniae (2) and NFGNB + b- haemolytic streptococci + H. influenzae (1)

Role of Interferon Gamma Release Assay in Active TB Diagnosis among HIV Infected Individuals

immunodeficiency virus (HIV) infected individuals. In this study, we assessed the sensitivity of Interferon gamma release assay (IGRA) in active tuberculosis patients who were positive for HIV infection and compared it with that of tuberculin skin test (TST). Methodology/Principal Findings: A total of 105 HIV-TB patients who were naı¨ve for anti tuberculosis and anti retroviral therapy were included for this study out of which 53 (50%) were culture positive. Of 105 tested, QuantiFERON-TB Gold intube (QFT-G) was positive in 65% (95% CI: 56% to 74%), negative in 18% (95% CI: 11% to 25%) and indeterminate in 17% (95% CI: 10% to 24%) of patients. The sensitivity of QFT-G remained similar in pulmonary TB and extra-pulmonary TB patients. The QFT-G positivity was not affected by low CD4 count, but it often gave indeterminate results especially in individuals with CD4 count ,200 cells/ml. All of the QFT-G indeterminate patients whose sputum culture were positive, showed #0.25 IU/ml of IFN-c response to phytohemagglutinin (PHA). TST was performed in all the 105 patients and yielded the sensitivity of 31% (95% CI: 40% to 22%). All the TST positives were QFT-G positives. The sensitivity of TST was decreased, when CD4 cell counts declined. Conclusions/Significance: Our study shows neither QFT-G alone or in combination with TST can be used to exclude the suspicion of active TB disease. However, unlike TST, QFT-G yielded fewer false negative results even in individuals with low CD4 count. The low PHA cut-off point for indeterminate results suggested in this study (#0.25 IU/ml) may improve the proportion of valid QFT-G results