Long term follow up of HIV-infected patients with tuberculosis treated with 6-month intermittent short course chemotherapy

Background . Tuberculosis occurs in 60%–70% of HIVpositive persons in India. The outcome of HIV-positive patients treated with 6-month intermittent short course antituberculosis regimens in India is not well described. Methods . This was a prospective observational feasibility study of 71 patients with HIV and tuberculosis who were treated with category I regimen of the Revised National Tuberculosis Control Programme (ethambutol, isoniazid, rifampicin and pyrazinamide thrice weekly for the initial 2 months followed by rifampicin and isoniazid thrice weekly for the next 4 months). Sputum was examined by smear and culture for Mycobacterium tuberculosis every month up to 24 months. Chest X-ray, CD4 cell count and viral load were done prior to and at the end of treatment. None of the patients received antiretroviral therapy. Results . We present here the treatment response of patients with sputum culture-positive pulmonary tuberculosis to category I regimen. By efficacy analysis, among 43 patients treated with category I regimen, sputum smear conversion was observed in 79% and culture conversion in 82% at the second month. A favourable response was seen in 72% of patients. The mean (SD) CD4% fell from 12.6 (5.9) to 8.9 (4.9) (p<0.001) with no significant change in mean (SD) CD4 cell count (169 [126] to 174 [158]; ns) at the end of treatment. Viral load change from 1.8x105 at baseline to 1.3x105 at the end of treatment was not statistically significant. Thirty-one patients, who completed the full course of treatment, were declared cured and were followed up for 24 months. Twelve had recurrent tuberculosis (39%); 16 of 43 (37%) patients had died by the end of 24 months, twothirds due to causes other than tuberculosis. Conclusion . Though the early bacteriological response to intermittent short course antituberculosis regimen was satisfactory, the overall outcome was adversely affected by the high mortality (during and after completion of treatment) and recurrence rate among HIV-infected patients with tuberculosis. Immune status deteriorated in spite of antituberculosis treatment, highlighting the need for antiretroviral treatment in addition to antituberculosis treatment to improve the long term outcome. The results of this pilot study need to be confirmed by larger studies

Structure of the Full-Length Major Pilin from Streptococcus pneumoniae: Implications for Isopeptide Bond Formation in Gram-Positive Bacterial Pili

The surface of the pneumococcal cell is adorned with virulence factors including pili. The major pilin RrgB, which forms the pilus shaft on pathogenic Streptococcus pneumoniae, comprises four immunoglobulin (Ig)-like domains, each with a common CnaB topology. The three C-terminal domains are each stabilized by internal Lys-Asn isopeptide bonds, formed autocatalytically with the aid of an essential Glu residue. The structure and orientation of the crucial N-terminal domain, which provides the covalent linkage to the next pilin subunit in the shaft, however, remain incompletely characterised. We report the crystal structure of full length RrgB, solved by X-ray crystallography at 2.8 Å resolution. The N-terminal (D1) domain makes few contacts with the rest of the RrgB structure, and has higher B-factors. This may explain why D1 is readily lost by proteolysis, as are the N-terminal domains of many major pilins. D1 is also found to have a triad of Lys, Asn and Glu residues in the same topological positions as in the other domains, yet mass spectrometry and the crystal structure show that no internal isopeptide bond is formed. We show that this is because β-strand G of D1, which carries the Asn residue, diverges from β-strand A, carrying the Lys residue, such that these residues are too far apart for bond formation. Strand G also carries the YPKN motif that provides the essential Lys residue for the sortase-mediated intermolecular linkages along the pilus shaft. Interaction with the sortase and formation of the intermolecular linkage could result in a change in the orientation of this strand, explaining why isopeptide bond formation in the N-terminal domains of some major pilins appears to take place only upon assembly of the pili

Hepatic steatosis does not cause insulin resistance in people with familial hypobetalipoproteinaemia

Item does not contain fulltextAIMS/HYPOTHESIS: Hepatic steatosis is strongly associated with hepatic and whole-body insulin resistance. It has proved difficult to determine whether hepatic steatosis itself is a direct cause of insulin resistance. In patients with familial hypobetalipoproteinaemia (FHBL), hepatic steatosis is a direct consequence of impaired hepatic VLDL excretion, independently of metabolic derangements. Thus, patients with FHBL provide a unique opportunity to investigate the relation between increased liver fat and insulin sensitivity. METHODS: We included seven male participants with FHBL and seven healthy matched controls. Intrahepatic triacylglycerol content and intramyocellular lipid content were measured using localised proton magnetic resonance spectroscopy ((1)H-MRS). A two-step hyperinsulinaemic-euglycaemic clamp, using stable isotopes, was assessed to determine hepatic and peripheral insulin sensitivity. RESULTS: (1)H-MRS showed moderate to severe hepatic steatosis in patients with FHBL. Basal endogenous glucose production (EGP) and glucose levels did not differ between the two groups, whereas insulin levels tended to be higher in patients compared with controls. Insulin-mediated suppression of EGP during lower dose insulin infusion and insulin-mediated peripheral glucose uptake during higher dose insulin infusion were comparable between FHBL participants and controls. Baseline fatty acids and lipolysis (glycerol turnover) at baseline and during the clamp did not differ between groups. CONCLUSIONS/INTERPRETATION: In spite of moderate to severe hepatic steatosis, people with FHBL do not display a reduction in hepatic or peripheral insulin sensitivity compared with healthy matched controls. These results indicate that hepatic steatosis per se is not a causal factor leading to insulin resistance. TRIAL REGISTRATION: ISRCTN35161775

Identification of Novel Pathogenicity Loci in Clostridium perfringens Strains That Cause Avian Necrotic Enteritis

Type A Clostridium perfringens causes poultry necrotic enteritis (NE), an enteric disease of considerable economic importance, yet can also exist as a member of the normal intestinal microbiota. A recently discovered pore-forming toxin, NetB, is associated with pathogenesis in most, but not all, NE isolates. This finding suggested that NE-causing strains may possess other virulence gene(s) not present in commensal type A isolates. We used high-throughput sequencing (HTS) technologies to generate draft genome sequences of seven unrelated C. perfringens poultry NE isolates and one isolate from a healthy bird, and identified additional novel NE-associated genes by comparison with nine publicly available reference genomes. Thirty-one open reading frames (ORFs) were unique to all NE strains and formed the basis for three highly conserved NE-associated loci that we designated NELoc-1 (42 kb), NELoc-2 (11.2 kb) and NELoc-3 (5.6 kb). The largest locus, NELoc-1, consisted of netB and 36 additional genes, including those predicted to encode two leukocidins, an internalin-like protein and a ricin-domain protein. Pulsed-field gel electrophoresis (PFGE) and Southern blotting revealed that the NE strains each carried 2 to 5 large plasmids, and that NELoc-1 and -3 were localized on distinct plasmids of sizes ∼85 and ∼70 kb, respectively. Sequencing of the regions flanking these loci revealed similarity to previously characterized conjugative plasmids of C. perfringens. These results provide significant insight into the pathogenetic basis of poultry NE and are the first to demonstrate that netB resides in a large, plasmid-encoded locus. Our findings strongly suggest that poultry NE is caused by several novel virulence factors, whose genes are clustered on discrete pathogenicity loci, some of which are plasmid-borne

Reduced NK activity in pulmonary tuberculosis patients with/without HIV infection: identifying the defective stage and studying the effect of interleukins on NK activity

Setting:A study was undertaken to understand the non-major histocompatibility restricted cytotoxicity in order to delineate the role of natural killer (NK) cells towards the development of host immunity to tuberculosis. Objective: (a) Enumeration of NK cellnumbers and activity in normal individuals (35), pulmonary tuberculosis patients (32),HIV-infected TB patients (20) and patient contacts (10), (b) effect of treatment on NK status, (c) enumeration of effector- target conjugates and (d) effect of in vitro cytokine stimulation on NKactivity. Design:NK cellswere enumerated by flowcytometry.NKactivity was assessed by chromiumrelease assay before and after treatment for tuberculosisandafter stimulationwith IL-2/IL-12.Novel flowcytometricmethodwasstandardizedto enumerate effector-target conjugates. Results: No changeswere seen between different groups as faras numberof NK cells and relative proportions of different conjugate typeswere concerned, but therewas a decrease in NKactivity in TB patientswhich increased after treatment.Augmentation of NKactivity was observed after cytokine stimulation. Conclusion: Lowered NKactivity during tuberculosisinfection isprobably the`effect'and not the`cause' for the disease as demonstrated by the follow-up study. Similar numberof conjugates in both groups indicates no defect in the recognition/ binding step but probably at subsequent steps of the cytotoxic process. Augmentation of NK activity with cytokines implicates themas potential adjuncts to tuberculosis chemotherap

Extensive dermatophytosis caused by Microsporum gypseum in an AIDS patient in Madras

[no abstract available

Miliary tuberculosis in human immunodeficiency virus infected patients not on antiretroviral therapy: clinical profile and response to shortcourse chemotherapy

Background: An increase in tuberculosis (TB) incidence has been associated with human immunodeficiency virus (HIV). Aims: To describe the clinical characteristics and treatment outcome of patients with HIV and miliary TB treated with short-course intermittent chemotherapy in the absence of access to highly active antiretroviral therapy (HAART). Settings and Design: Prospective study of HIV infected adults referred to a TB clinic between July 1999 and July 2004. Materials and Methods: On diagnosis of miliary TB, patients were treated with a standard regimen of two months of isoniazid, rifampicin, ethambutol and pyrazinamide followed by four months of isoniazid and rifampicin (2EHRZ₃/4RH₃) thrice weekly and followed up for 24 months. Patients were reviewed clinically every month and two sputa were collected. Chest radiographs and blood investigations were done at two months, end of treatment and every six months thereafter. Results: Of 498 patients with HIV and tuberculosis, 31 (6%) were diagnosed as miliary tuberculosis. At diagnosis, sputum smear was positive for acid-fast bacilli (AFB) in 14 patients (45%) and Mycobacterium tuberculosis was isolated in 21 (68%). The mean CD4 cell count was 129 &#177; 125 cells/mm³. Twenty-five patients were declared cured at the end of treatment (81%) while one (3%) died and five (16%) failed. The recurrence rate was 19.4/100 person-years and the median survival was 17 months (95% CI 14 to 20). None of the patients received antiretroviral therapy. Conclusions: Miliary TB tends to occur among HIV infected patients with severe immunosuppression. Though the initial response to short-course chemotherapy was encouraging, a high recurrence rate and mortality was observed indicating poor prognosis in HIV