Localization of EccA at the growing pole in Mycobacterium smegmatis.

Background: Bacteria require specialized secretion systems for the export of molecules into the extracellular space to modify their environment and scavenge for nutrients. The ESX-3 secretion system is required by mycobacteria for iron homeostasis. The ESX-3 operon encodes for one cytoplasmic component (EccA) and five membrane components (EccB3 - EccE3 and MycP).

Identifying nucleic acid-associated proteins in Mycobacterium smegmatis by mass spectrometry-based proteomics.

Background: Transcriptional responses required to maintain cellular homeostasis or to adapt to environmental stress, is in part mediated by several nucleic-acid associated proteins. In this study, we sought to establish an affinity purification-mass spectrometry (AP-MS) approach that would enable the collective identification of nucleic acid-associated proteins in mycobacteria. We hypothesized that targeting the RNA polymerase complex through affinity purification would allow for the identification of RNA- and DNA-associated proteins that not only maintain the bacterial chromosome but also enable transcription and translation.

Moxifloxacin retains antimycobacterial activity in the presence of gyrA mutations.

Moxifloxacin-resistant Mycobacterium tuberculosis mutants were selected in vitro using different concentrations of moxifloxacin. gyrA mutations at codons 88 and 94 were associated with resistance (defined as an MIC of ≥2 μg/ml) (P < 0.0001 and P = 0.

Effect of household and community interventions on the burden of tuberculosis in southern Africa: the ZAMSTAR community-randomised trial.

Background: Southern Africa has had an unprecedented increase in the burden of tuberculosis, driven by the HIV epidemic. The Zambia, South Africa Tuberculosis and AIDS Reduction (ZAMSTAR) trial examined two public health interventions that aimed to reduce the burden of tuberculosis by facilitating either rapid sputum diagnosis or integrating tuberculosis and HIV services within the community.

Methods: ZAMSTAR was a community-randomised trial done in Zambia and the Western Cape province of South Africa.

Genotype MTBDRsl line probe assay shortens time to diagnosis of extensively drug-resistant tuberculosis in a high-throughput diagnostic laboratory.

Rationale: Conventional culture-based drug susceptibility testing (DST) for the second-line antituberculosis drugs is slow, leading to diagnostic delay with associated exacerbation of transmission, amplification of resistance, and increased mortality.

Objectives: To assess the diagnostic performance of the GenoType MTBDRsl line probe assay (LPA) for the rapid detection of mutations conferring resistance to ofloxacin (OFX), amikacin (AMK), and ethambutol and to determine the impact of implementation on the turnaround time in a high-throughput diagnostic laboratory.

Methods: Six hundred and fifty-seven direct patient acid-fast bacilli smear-positive specimens resistant to isoniazid, rifampin, or both according to the GenoType MTBDRplus assay were consecutively tested, using the GenoType MTBDRsl LPA.

Population structure of multi- and extensively drug-resistant Mycobacterium tuberculosis strains in South Africa.

Genotyping of multidrug-resistant (MDR) Mycobacterium tuberculosis strains isolated from tuberculosis (TB) patients in four South African provinces (Western Cape, Eastern Cape, KwaZulu-Natal, and Gauteng) revealed a distinct population structure of the MDR strains in all four regions, despite the evidence of substantial human migration between these settings. In all analyzed provinces, a negative correlation between strain diversity and an increasing level of drug resistance (from MDR-TB to extensively drug-resistant TB [XDR-TB]) was observed. Strains predominating in XDR-TB in the Western and Eastern Cape and KwaZulu-Natal Provinces were strongly associated with harboring an inhA promoter mutation, potentially suggesting a role of these mutations in XDR-TB development in South Africa.

Pulmonary infection due to Mycobacterium goodii in a spotted hyena (Crocuta crocuta) from South Africa.

We report a case of pyogranulomatous pneumonia due to infection with Mycobacterium goodii in an adult female spotted hyena (Crocuta crocuta). The lungs of the animal showed consolidated, granulomatous lesions, and they were extensively and severely infiltrated. Polymerase chain reaction sequencing of isolated crude lung tissue DNA, and boiled lung culture samples, all confirmed that the causative organism was M.

Detection of natural infection with Mycobacterium intracellulare in healthy wild-caught Chacma baboons (Papio ursinus) by ESAT-6 and CFP-10 IFN-gamma ELISPOT tests following a tuberculosis outbreak.

Background: Both tuberculous and non-tuberculous mycobacteria can cause infection in nonhuman primates (NHP), indicating the existence of potential zoonotic transmission between these animals and visitors to zoos or animal handlers in primate facilities. Screening of mycobacterial infections in NHP is traditionally done by tuberculin skin test (TST), which is unable to distinguish between pathogenic and non-pathogenic mycobacterial infections. In this study, we investigated the use of ESAT-6 and CFP-10 for detection of mycobacterial infections in a wild-caught baboon colony after one baboon died of tuberculosis (TB).

Bovine tuberculosis in African buffaloes: observations regarding Mycobacterium bovis shedding into water and exposure to environmental mycobacteria.

Background: African buffaloes are the maintenance host for Mycobacterium bovis in the endemically infected Kruger National Park (KNP). The infection is primarily spread between buffaloes via the respiratory route, but it is not known whether shedding of M. bovis in nasal and oral excretions may lead to contamination of ground and surface water and facilitate the transmission to other animal species.

Safe Mycobacterium tuberculosis DNA extraction method that does not compromise integrity.

Concern has been raised about the efficacy of the heat killing of mycobacteria during the isolation of DNA. We demonstrate a method that allows for the efficient killing of Mycobacterium tuberculosis without compromising DNA integrity for subsequent molecular investigation. This method reduces the risk of infection to the research scientist.

Tuberculosis due to resistant Haarlem strain, Tunisia.

Multidrug-resistant tuberculosis was diagnosed in 21 HIV-negative, nonhospitalized male patients residing in northern Tunisia. A detailed investigation showed accelerated transmission of a Mycobacterium tuberculosis clone of the Haarlem type in 90% of all patients. This finding highlights the epidemic potential of this prevalent genotype.

Reinfection and mixed infection cause changing Mycobacterium tuberculosis drug-resistance patterns.

Rationale: Multiple infections with different strains of Mycobacterium tuberculosis may occur in settings where the infection pressure is high. The relevance of mixed infections for the patient, clinician, and control program remains unclear.

Objectives: This study aimed to describe reinfection and mixed infection as underlying mechanisms of changing drug-susceptibility patterns in serial sputum cultures.

Mycosin-1, a subtilisin-like serine protease of Mycobacterium tuberculosis, is cell wall-associated and expressed during infection of macrophages.

Background: Exported proteases are commonly associated with virulence in bacterial pathogens, yet there is a paucity of information regarding their role in Mycobacterium tuberculosis. There are five genes (mycP1-5) present within the genome of Mycobacterium tuberculosis H37Rv that encode a family of secreted, subtilisin-like serine proteases (the mycosins). The gene mycP1 (encoding mycosin-1) was found to be situated 3700 bp (four ORF's) from the RD1 deletion region in the genome of the attenuated vaccine strain M.