Timing of Antiretroviral Therapy for HIV in the Setting of TB Treatment

The convergent human immunodeficiency virus (HIV) and tuberculosis (TB) pandemics continue to collectively exact significant morbidity and mortality worldwide. Highly active antiretroviral therapy (HAART) has been a critical component in combating the scourge of these two conditions as both a preemptive and therapeutic modality. However, concomitant administration of antiretroviral and antituberculous therapies poses significant challenges, including cumulative drug toxicities, drug-drug interactions, high pill burden, and the immune reconstitution inflammatory syndrome (IRIS), thus complicating the management of coinfected individuals. This paper will review data from recent studies regarding the optimal timing of HAART initiation relative to TB treatment, with the ultimate goal of improving coinfection-related morbidity and mortality while mitigating toxicity resulting from concurrent treatment of both infections

Multidrug-Resistant Tuberculosis in Panama Is Driven by Clonal Expansion of a Multidrug-Resistant Mycobacterium tuberculosis Strain Related to the KZN Extensively Drug-Resistant M. tuberculosis Strain from South Africa

Multidrug-resistant tuberculosis (MDR-TB) is a significant health problem in Panama. The extent to which such cases are the result of primary or acquired resistance and the strain families involved are unknown. We performed whole-genome sequencing of a collection of 66 clinical MDR isolates, along with 31 drug-susceptible isolates, that were isolated in Panama between 2001 and 2010; 78% of the MDR isolates belong to the Latin American-Mediterranean (LAM) family. Drug resistance mutations correlated well with drug susceptibility profiles. To determine the relationships among these strains and to better understand the acquisition of resistance mutations, a phylogenetic tree was constructed based on a genome-wide single-nucleotide polymorphism analysis. The phylogenetic tree shows that the isolates are highly clustered, with a single strain (LAM9-c1) accounting for nearly one-half of the MDR isolates (29/66 isolates). The LAM9-c1 strain was most prevalent among male patients of working age and was associated with high mortality rates. Members of this cluster all share identical mutations conferring resistance to isoniazid (KatG S315T mutation), rifampin (RpoB S531L mutation), and streptomycin (rrs C517T mutation). This evidence of primary resistance supports a model in which MDR-TB in Panama is driven by clonal expansion and ongoing transmission of several strains in the LAM family, including the highly successful MDR strain LAM9-c1. The phylogenetic analysis also shows that the LAM9-c1 strain is closely related to the KwaZulu-Natal (KZN) extensively drug-resistant TB strain identified in KwaZulu-Natal, South Africa. The LAM9-c1 and KZN strains likely arose from a recent common ancestor that was transmitted between Panama and South Africa and had the capacity to tolerate an accumulation of multiple resistance mutations

Mycobacterium avium complex immune reconstitution inflammatory syndrome: Long term outcomes

Abstract Background To describe long term outcomes of Mycobacterium avium complex (MAC) immune reconstitution inflammatory syndrome (IRIS). Methods Cases of MAC IRIS were retrospectively identified at four HIV clinics (Michigan, Maryland, Rhode Island, and Indiana) from 1996–2004. Patients were included if they were initially diagnosed with AIDS and found to have evidence of focal MAC infection documented by tissue culture or PCR after initiating HAART, and at least 6 months of follow up. Results Among the 20 patients included, the mean age was 40 years, mean CD4 cell count was 24/mm3 at pretreatment baseline and 100/mm3 at time of MAC IRIS diagnosis. Sites of disease included lymph nodes (15 patients [8 peripheral, 8 abdominal and 1 peripheral and abdominal]), gastrointestinal tract (7) and liver (3). Sixteen patients (80%) responded to treatment and were disease free after a mean of 17.4 months of therapy for MAC IRIS; IRIS therapy was withdrawn in 6 without relapse. Four patients (non-responder group) had persistent or relapsing disease despite 27 months of ongoing MAC IRIS treatment. At the time of resolution or last follow-up, the mean CD4 cell count and viral load was 143/mm3 and 7,000 c/mL for responders, and 65/mm3 and 17,000 c/mL for non-responders, respectively. Most patients with peripheral adenopathy were responders (7/8; 88%); many with abdominal adenopathy (4/8; 50%) were nonresponders. Conclusion The majority of patients with MAC IRIS eventually responded to treatment. Our sample size was not adequate to perform statistical analysis, but there was a tendency towards adequate CD4 response to HAART and peripheral rather than intraabdominal adenopathy among responders.http://deepblue.lib.umich.edu/bitstream/2027.42/112767/1/12967_2007_Article_210.pd

Improvement of Tuberculosis Laboratory Capacity on Pemba Island, Zanzibar: A Health Cooperation Project.

Low-income countries with high Tuberculosis burden have few reference laboratories able to perform TB culture. In 2006, the Zanzibar National TB Control Programme planned to decentralize TB diagnostics. The Italian Cooperation Agency with the scientific support of the "L. Spallanzani" National Institute for Infectious Diseases sustained the project through the implementation of a TB reference laboratory in a low-income country with a high prevalence of TB. The implementation steps were: 1) TB laboratory design according to the WHO standards; 2) laboratory equipment and reagent supplies for microscopy, cultures, and identification; 3) on-the-job training of the local staff; 4) web- and telemedicine-based supervision. From April 2007 to December 2010, 921 sputum samples were received from 40 peripheral laboratories: 120 TB cases were diagnosed. Of all the smear-positive cases, 74.2% were culture-positive. During the year 2010, the smear positive to culture positive rate increased up to 100%. In March 20, 2010 the Ministry of Health and Social Welfare of Zanzibar officially recognized the Public Health Laboratory- Ivo de Carneri as the National TB Reference Laboratory for the Zanzibar Archipelago. An advanced TB laboratory can represent a low cost solution to strengthen the TB diagnosis, to provide capacity building and mid-term sustainability

Dormancy Phenotype Displayed by Extracellular Mycobacterium tuberculosis within Artificial Granulomas in Mice

Mycobacterium tuberculosis residing within pulmonary granulomas and cavities represents an important reservoir of persistent organisms during human latent tuberculosis infection. We present a novel in vivo model of tuberculosis involving the encapsulation of bacilli in semidiffusible hollow fibers that are implanted subcutaneously into mice. Granulomatous lesions develop around these hollow fibers, and in this microenvironment, the organisms demonstrate an altered physiologic state characterized by stationary-state colony-forming unit counts and decreased metabolic activity. Moreover, these organisms show an antimicrobial susceptibility pattern similar to persistent bacilli in current models of tuberculosis chemotherapy in that they are more susceptible to the sterilizing drug, rifampin, than to the bactericidal drug isoniazid. We used this model of extracellular persistence within host granulomas to study both gene expression patterns and mutant survival patterns. Our results demonstrate induction of dosR (Rv3133c) and 20 other members of the DosR regulon believed to mediate the transition into dormancy, and that relMtb is required for Mycobacterium tuberculosis survival during extracellular persistence within host granulomas. Interestingly, the dormancy phenotype of extracellular M. tuberculosis within host granulomas appears to be immune mediated and interferon-γ dependent

A SARS-CoV-2 RBD vaccine fused to the chemokine MIP-3α elicits sustained murine antibody responses over 12 months and enhanced lung T-cell responses

BackgroundPrevious studies have demonstrated enhanced efficacy of vaccine formulations that incorporate the chemokine macrophage inflammatory protein 3α (MIP-3α) to direct vaccine antigens to immature dendritic cells. To address the reduction in vaccine efficacy associated with a mutation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants, we have examined the ability of receptor-binding domain vaccines incorporating MIP-3α to sustain higher concentrations of antibody when administered intramuscularly (IM) and to more effectively elicit lung T-cell responses when administered intranasally (IN).MethodsBALB/c mice aged 6–8 weeks were immunized intramuscularly or intranasally with DNA vaccine constructs consisting of the SARS-CoV-2 receptor-binding domain alone or fused to the chemokine MIP-3α. In a small-scale (n = 3/group) experiment, mice immunized IM with electroporation were followed up for serum antibody concentrations over a period of 1 year and for bronchoalveolar antibody levels at the termination of the study. Following IN immunization with unencapsulated plasmid DNA (n = 6/group), mice were evaluated at 11 weeks for serum antibody concentrations, quantities of T cells in the lungs, and IFN-γ- and TNF-α-expressing antigen-specific T cells in the lungs and spleen.ResultsAt 12 months postprimary vaccination, recipients of the IM vaccine incorporating MIP-3α had significantly, approximately threefold, higher serum antibody concentrations than recipients of the vaccine not incorporating MIP-3α. The area-under-the-curve analyses of the 12-month observation interval demonstrated significantly greater antibody concentrations over time in recipients of the MIP-3α vaccine formulation. At 12 months postprimary immunization, only recipients of the fusion vaccine had concentrations of serum-neutralizing activity deemed to be effective. After intranasal immunization, only recipients of the MIP-3α vaccine formulations developed T-cell responses in the lungs significantly above those of PBS controls. Low levels of serum antibody responses were obtained following IN immunization.ConclusionAlthough requiring separate IM and IN immunizations for optimal immunization, incorporating MIP-3α in a SARS-CoV-2 vaccine construct demonstrated the potential of a stable and easily produced vaccine formulation to provide the extended antibody and T-cell responses that may be required for protection in the setting of emerging SARS-CoV-2 variants. Without electroporation, simple, uncoated plasmid DNA incorporating MIP-3α administered intranasally elicited lung T-cell responses

Transcriptional Approach for Decoding the Mechanism of rpoC Compensatory Mutations for the Fitness Cost in Rifampicin-Resistant Mycobacterium tuberculosis

Multidrug-resistant tuberculosis (TB), defined as TB resistant to the two first-line drugs, isoniazid and rifampin, is a serious challenge to global TB eradication efforts. Although mutations in rpoA or rpoC have been proposed to compensate for this fitness cost due to rpoB mutation in rifampicin-resistant Mycobacterium tuberculosis mutants, whether the compensatory effect exists and the underlying mechanisms of compensation remain unclear. Here, we used RNA sequencing to investigate the global transcriptional profiles of 6 rifampin-resistant clinical isolates with either single mutation in rpoB or dual mutations in rpoB/rpoC, as well as 3 rifampin-susceptible clinical isolates, trying to prove the potential compensatory effect of rpoC by transcriptomic alteration. In rifampin-free conditions, rpoC mutation was associated with M. tuberculosis upregulation of ribosomal protein-coding genes, dysregulation of growth-related essential genes and balancing the expression of arginine and glutamate synthesis-associated genes. Upon rifampin exposure of M. tuberculosis isolates, rpoC mutations were associated with the upregulation of the oxidative phosphorylation machinery, which was inhibited in the rpoB single mutants, as well as stabilization of the expression of rifampin-regulated essential genes and balancing the expression of genes involved in metabolism of sulfur-containing amino acids. Taken together, our data suggest that rpoC mutation may compensate for the fitness defect of rifampicin-resistant M. tuberculosis by altering gene expression in response to rifampin exposure

Unprecedented in Vitro Antitubercular Activitiy of Manganese(II) Complexes Containing 1,10- Phenanthroline and Dicarboxylate Ligands: Increased Activity, Superior Selectivity, and Lower Toxicity in Comparison to Their Copper(II) Analogs

Mycobacterium tuberculosis is the etiologic agent of tuberculosis. The demand for new chemotherapeutics with unique mechanisms of action to treat (multi)resistant strains is an urgent need. The objective of this work was to test the effect of manganese(II) and copper(II) phenanthroline/dicarboxylate complexes against M. tuberculosis. The water-soluble Mn(II) complexes, [Mn2(oda)(phen)4(H2O)2][Mn2(oda)(phen)4(oda)2]·4H2O (1) and ([Mn(3,6,9-tdda)(phen)2]·3H2O·EtOH)n (3) (odaH2 = octanedioic acid, phen = 1,10-phenanthroline, tddaH2 = 3,6,9-trioxaundecanedioic acid), and water-insoluble complexes, [Mn(ph)(phen)(H2O)2] (5), [Mn(ph)(phen)2(H2O)]·4H2O (6), [Mn2(isoph)2(phen)3]·4H2O (7), ([Mn(phen)2(H2O)2])2(isoph)2(phen)·12H2O (8) and [Mn(tereph)(phen)2]·5H2O (9) (phH2 = phthalic acid, isophH2 = isophthalic acid, terephH2 = terephthalic acid), robustly inhibited the viability of M. tuberculosis strains, H37Rv and CDC1551. The water-soluble Cu(II) analog of (1), [Cu2(oda)(phen)4](ClO4)2·2.76H2O·EtOH (2), was significantly less effective against both strains. Whilst (3) retarded H37Rv growth much better than its soluble Cu(II) equivalent, ([Cu(3,6,9-tdda)(phen)2]·3H2O·EtOH)n (4), both were equally efficient against CDC1551. VERO and A549 mammalian cells were highly tolerant to the Mn(II) complexes, culminating in high selectivity index (SI) values. Significantly, in vivo studies using Galleria mellonella larvae indicated that the metal complexes were minimally toxic to the larvae. The Mn(II) complexes presented low MICs and high SI values (up to 1347), indicating their auspicious potential as novel antitubercular lead agents. © 2018 McCarron, McCann, Devereux, Kavanagh, Skerry, Karakousis, Aor, Mello, Santos, Campos and Pavan

Molecular immunologic correlates of spontaneous latency in a rabbit model of pulmonary tuberculosis

Background: Infection of humans with Mycobacterium tuberculosis (Mtb) results in latent tuberculosis infection (LTBI) in 90-95% of immune competent individuals, with no symptoms of active disease. The World Health Organization estimates that 1.5 billion people have LTBI, which can reactivate in the setting of waning host immunity, posing a threat to global TB control. Various animal models have been used to study the pathogenesis of TB. However, besides nonhuman primates, rabbits are the only animal model that fully recapitulates the pathological features of human TB, including progressive disease with necrosis and cavitation or establishment of spontaneous latency. Results: We defined the molecular immunological correlates of LTBI establishment in a rabbit model of pulmonary infection with Mtb CDC1551. After aerosol infection, exponential bacterial growth was noted in the lungs for 4 weeks, followed by a significant decline by 12 weeks, resulting in the absence of cultivable bacilli by 24 weeks. We used rabbit whole genome microarrays to profile the lung transcriptome during the course of infection. At 2 weeks post-infection, gene networks involved in natural killer (NK) and dendritic cell (DC) activation and macrophage antimicrobial activities were highly upregulated. This was followed by upregulation of gene networks involved in macrophage and T cell activation and autophagy, peaking at 4 to 8 weeks. Concomitantly, host Th1, but not Th2 or inflammatory, immune response genes were significantly upregulated. Thus, the expression kinetics of genes involved in cross-talk between innate and adaptive immunity over the first 8 weeks post-infection were consistent with early efficient control of infection in the lungs. Interestingly, expression of many genes of the host innate and adaptive immune response pathways was downregulated at 12 weeks, suggesting that immune activation did not persist once bacilli began to clear from the infected lungs. Conclusions: Our results suggest that early activation of host innate immunity prior to efficient activation of T cell-mediated adaptive immunity but not inflammation is essential for establishment of LTBI in Mtb CDC1551-infected rabbits. We also show that T cell activation and the host adaptive immune response networks are dampened once bacterial growth is controlled, ultimately resulting in spontaneous LTBI