Outcomes among HIV-1 Infected Individuals First Starting Antiretroviral Therapy with Concurrent Active TB or Other AIDS-Defining Disease

Background

Tuberculosis (TB) is common among HIV-infected individuals in many resource-limited countries and has been associated with poor survival. We evaluated morbidity and mortality among individuals first starting antiretroviral therapy (ART) with concurrent active TB or other AIDS-defining disease using data from the “Prospective Evaluation of Antiretrovirals in Resource-Limited Settings” (PEARLS) study.

Methods

Participants were categorized retrospectively into three groups according to presence of active confirmed or presumptive disease at ART initiation: those with pulmonary and/or extrapulmonary TB (“TB” group), those with other non-TB AIDS-defining disease (“other disease”), or those without concurrent TB or other AIDS-defining disease (“no disease”). Primary outcome was time to the first of virologic failure, HIV disease progression or death. Since the groups differed in characteristics, proportional hazard models were used to compare the hazard of the primary outcome among study groups, adjusting for age, sex, country, screening CD4 count, baseline viral load and ART regimen.

Results

31 of 102 participants (30%) in the “TB” group, 11 of 56 (20%) in the “other disease” group, and 287 of 1413 (20%) in the “no disease” group experienced a primary outcome event (p = 0.042). This difference reflected higher mortality in the TB group: 15 (15%), 0 (0%) and 41 (3%) participants died, respectively (p<0.001). The adjusted hazard ratio comparing the “TB” and “no disease” groups was 1.39 (95% confidence interval: 0.93–2.10; p = 0.11) for the primary outcome and 3.41 (1.72–6.75; p<0.001) for death.

Conclusions

Active TB at ART initiation was associated with increased risk of mortality in HIV-1 infected patients.     

Evidence of selection for protein introns in the recAs of pathogenic mycobacteria.

Protein introns are recently discovered genetic elements whose intervening sequences are removed from a precursor protein by an unusual protein splicing reaction. This involves the excision of a central spacer molecule, the protein intron, and the religation of the amino- and carboxy-terminal fragments of the precursor. The recA gene of Mycobacterium tuberculosis contains one such element and we now show that the other major mycobacterial pathogen, Mycobacterium leprae, also possesses a protein intron in its recA, although other mycobacterial recA genes do not. However, these two protein introns are different in size, sequence and location of insertion of their coding sequences into the recAs of M. tuberculosis and M. leprae, indicating that acquisition of the protein introns has occurred independently in the two species, and thus suggesting that there has been selection for splicing in the maturation of RecA in the pathogenic mycobacteria. The M. leprae protein intron provides an example of conditional protein splicing, splicing occurring in M. leprae itself but not when expressed in Escherichia coli, unlike most previously described protein introns. These observations suggest that protein introns may perform a function for their host, rather than being just selfish elements.     

Mineralization and transformation of monofluorophenols by Pseudonocardia benzenivorans

The aerobic metabolism of monofluorophenols (mono-FPs) by the actinomycete, Pseudonocardia benzenivorans, was studied. This strain was able to grow on 4-fluorophenol (4-FP) and readily transform 2- and 3-fluorophenol to the corresponding metabolites. The detailed mechanism of mono-FPs degradation by P. benzenivorans was elucidated from enzymatic assays and the identification of reaction intermediates by high-performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry. Two types of fluorocatechols (i.e., 3- and 4-fluorocatechol) were identified as the key transformation products. During 4-FP degradation, only 4-fluorocatechol was detected, and a stoichiometric level of fluoride was released. Both fluorocatechols were observed together in cultures containing 3-fluorophenol (3-FP), while only 3-fluorocatechol was found to accumulate in 2-fluorophenol (2-FP)-containing cultures. Whole-cell extracts of P. benzenivorans expressed catechol 1,2-dioxygenase activity, indicating that the transformation of the three tested mono-FPs proceeded via ortho-cleavage pathway. The results presented in this paper provide comprehensive information regarding the metabolism of mono-FPs by a single bacterium.     

Genetic heterogeneity in the Indian stocks of seahorse (<Emphasis Type="Italic">Hippocampus kuda</Emphasis> and <Emphasis Type="Italic">Hippocampus trimaculatus</Emphasis>) inferred from mtDNA cytochrome b gene

Genetic stock structure analysis of two seahorse species from the south east and south west coasts of India (37 samples of Hippocampus kuda and 39 samples of Hippocampus trimaculatus from Kollam (Kerala) and Mandapam (Tamil Nadu)) was carried out through sequence variation analysis of a 350 bp cytochrome b fragment of mitochondrial DNA. This was taken up to support the breeding and restocking programme of these species in natural habitats for conservation purpose. The occurrence of strong genetic subdivision among the samples, detected by the analysis of molecular variance (AMOVA), and significant Φ_ST values indicated that stocks of both the species in the two Indian coasts are distinct. The findings of the present study have important implications for conservation and management of these two species and we recommend stock-specific, breeding assisted sea-ranching programme for H. kuda and H. trimaculatus along the Indian coasts. Handling editor: K. Martens     

Mitochondrial dysfunction and genetic heterogeneity in chronic periodontitis

We performed an extensive study on mitochondrial dysfunction in chronic periodontitis (CP). Electron microscopic analysis of gingival cells revealed abnormal mitochondria in 60% of the patients. Mitochondrial membrane potential and oxygen consumption of gingival cells were reduced by 4 fold and 5.8 fold, respectively; whereas ROS production was increased by 18%. The genetic analysis by complete mitochondrial DNA sequencing revealed the identification of 14 novel mutations only in periodontal tissues but not in the blood, suggesting a role of oxidative stress on periodontal tissues. Thus, our functional and genetic analysis provided an evidence for the mitochondrial dysfunction in CP.     

Bactericidal and non-cytotoxic activity of bacteriocin produced by Lacticaseibacillus paracasei F9-02 and evaluation of its tolerance to various physico-chemical conditions

This study aims to explore novel lactic acid bacteria (LAB) from breast-fed infants' faeces towards characterizing their antimicrobial compound, bacteriocin. The LAB, Lacticaseibacillus paracasei F9-02 showed strong antimicrobial activity against clinical pathogens. Their proteinaceous nature was confirmed as the activity was completely abolished when treated with proteinaceous enzymes and retained during neutral pH and catalase treatment. The purified bacteriocin showed antimicrobial activity at the minimum inhibitory concentration (MIC) value of 7.56 μg/ml against vancomycin-resistant Enterococcus sp. [vancomycin-resistant enterococcal (VRE)], and methicillin-resistant Staphylococcus aureus (MRSA), 15.13 μg/ml against Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype typhi and 30.25 μg/ml against Shigella flexneri. Present study also proved the bactericidal, non-cytotoxic and non-hemolytic nature of bacteriocin. Additionally, bacteriocin retained their stability under various physico-chemical conditions, broad range of pH (2–10), temperature (40–121°C), enzymes (amylase, lipase and lysozyme), surfactants [Tween-20, 80, 100 and sodium dodecyl sulfate (SDS)], metal ions (CaCl₂, FeSO₄, ZnSO₄, MgSO₄, MnSO₄, CuCl₂) and NaCl (2%–8%). The molecular weight of bacteriocin (~28 kDa) was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), functional and active groups were assessed by Fourier Transform-Infrared (FT-IR). To our knowledge, this is the first study reporting L. paracasei from breast-fed infants' faeces and assessing their antimicrobial compound, bacteriocin. The study results furnish the essential features to confirm the therapeutic potential of L. paracasei F9-02 bacteriocin.     

Correlates of HIV and malaria co-infection in Southern India

ABSTRACT: BACKGROUND: Malaria and HIV co-infection adversely impact the outcome of both diseases and previous studies have mostly focused on falciparum malaria. Plasmodium vivax contributes to almost half of the malaria cases in India, but the disease burden of HIV and P. vivax co-infection is unclear. METHODS: HIV-infected subjects (n=460) were randomly selected from the 4,611 individuals seen at a Voluntary Counseling and Testing Center in Chennai, India between Jan 2 to Dec 31 2008. Malaria testing was performed on stored plasma samples by both nested PCR using both genus-specific and species-specific primers and immunochromatography-based rapid diagnostic test for detecting antibodies against both Plasmodium falciparum and P. vivax. RESULTS: Recent malaria co-infection, defined by the presence of antibodies, was detected in 9.8% (45/460) participants. Plasmodium vivax accounted for majority of the infections (60%) followed by P. falciparum (27%) and mixed infections (13%). Individuals with HIV and malaria co-infection were more likely to be men (p=0.01). Between those with and without malaria, there was no difference in age (p=0.14), CD4+ T-cell counts (p=0.19) or proportion CD4+ T-cell below 200/mL (p=0.51). CONCLUSIONS: Retrospective testing of stored plasma samples for malaria antibodies can facilitate identification of populations with high rates of co-infection, and in this southern India HIVinfected cohort there was a considerable burden of malaria co-infection, predominantly due to P. vivax. However, the rate of P. falciparum infection was more than 6-fold higher among HIV-infected individuals than what would be expected in the general population in the region. Interestingly, individuals co-infected with malaria and HIV were not more likely to be immunosuppressed than individuals with HIV infection alone.     

L712V mutation in the androgen receptor gene causes complete androgen insensitivity syndrome due to severe loss of androgen function

Inability to respond to the circulating androgens is named as androgen insensitivity syndrome (AIS). Mutations in the androgen receptor (AR) gene are the most common cause of AIS. A cause and effect relationship between some of these mutations and the AIS phenotype has been proven by in vitro studies. Several other mutations have been identified, but need to be functionally validated for pathogenicity. Screening of the AR mutations upon presumptive diagnosis of AIS is recommended. We analyzed a case of complete androgen insensitivity syndrome (CAIS) for mutations in the AR gene. Sequencing of the entire coding region revealed C > G mutation (CTT–GTT) at codon 712 (position according to the NCBI database) in exon 4 of the gene, resulting in replacement of leucine with valine in the ligand-binding domain of the AR protein. No incidence of this mutation was observed in 230 normal male individuals analyzed for comparison. In vitro androgen binding and transactivation assays using mutant clone showed approximately 71% loss of ligand binding and about 76% loss of transactivation function. We conclude that CAIS in this individual was due to L712V substitution in the androgen receptor protein.     

The cost-effectiveness of tuberculosis preventive therapy for HIV-infected individuals in southern India: a trial-based analysis

Background

Regimens for isoniazid-based preventive therapy (IPT) for tuberculosis (TB) in HIV-infected individuals have not been widely adopted given concerns regarding efficacy, adherence and drug resistance. Further, the cost-effectiveness of IPT has not been studied in India.

Methods

We used an HIV/TB model to project TB incidence, life expectancy, cost and incremental cost-effectiveness of six months of isoniazid plus ethambutol (6EH), thirty-six months of isoniazid (36H) and no IPT for HIV-infected patients in India. Model input parameters included a median CD4 count of 324 cells/mm³, and a rate ratio of developing TB of 0.35 for 6EH and 0.22 for 36H at three years as compared to no IPT. Results of 6EH and 36H were also compared to six months of isoniazid (6H), three months of isoniazid plus rifampin (3RH) and three months of isoniazid plus rifapentine (3RPTH).

Results

Projected TB incidence decreased in the 6EH and 36H regimens by 51% and 62% respectively at three-year follow-up compared to no IPT. Without IPT, projected life expectancy was 136.1 months at a lifetime per person cost of $5,630. 6EH increased life expectancy by 0.8 months at an additional per person cost of $100 (incremental cost-effectiveness ratio (ICER) of $1,490/year of life saved (YLS)). 36H further increased life expectancy by 0.2 months with an additional per person cost of $55 (ICER of $3,120/YLS). The projected clinical impact of 6EH was comparable to 6H and 3RH; however when compared to these other options, 6EH was no longer cost-effective given the high cost of ethambutol. Results were sensitive to baseline CD4 count and adherence.

Conclusions

Three, six and thirty-six-month regimens of isoniazid-based therapy are effective in preventing TB. Three months of isoniazid plus rifampin and six-months of isoniazid are similarly cost-effective in India, and should be considered part of HIV care.