A significant knowledge gap exists concerning the geographical distribution of nontuberculous mycobacteria (NTM) isolation worldwide.To provide a snapshot of NTM species distribution, global partners in the NTM-Network European Trials Group (NET) framework (www.ntm-net.org), a branch of the Tuberculosis Network European Trials Group (TB-NET), provided identification results of the total number of patients in 2008 in whom NTM were isolated from pulmonary samples. From these data, we visualised the relative distribution of the different NTM found per continent and per country.We received species identification data for 20 182 patients, from 62 laboratories in 30 countries across six continents. 91 different NTM species were isolated. Mycobacterium avium complex (MAC) bacteria predominated in most countries, followed by M. gordonae and M. xenopi. Important differences in geographical distribution of MAC species as well as M. xenopi, M. kansasii and rapid-growing mycobacteria were observed.This snapshot demonstrates that the species distribution among NTM isolates from pulmonary specimens in the year 2008 differed by continent and differed by country within these continents. These differences in species distribution may partly determine the frequency and manifestations of pulmonary NTM disease in each geographical location. @ERSpublications Species distribution among nontuberculous mycobacteria isolates from pulmonary specimens is geographically diverse

Conventional phenotypic drug susceptibility testing (DST) methods for Mycobacterium tuberculosis are laborious and very time-consuming. Early detection of drug-resistant tuberculosis (TB) is essential for prevention and control of TB transmission. We have developed a pyrosequencing method for simultaneous detection of mutations associated with resistance to rifampin, isoniazid, ethambutol, amikacin, kanamycin, capreomycin, and ofloxacin. Seven pyrosequencing assays were optimized for following loci: rpoB , katG , embB , rrs , gyrA , and the promoter regions of inhA and eis . The molecular method was evaluated on a panel of 290 clinical isolates of M. tuberculosis . In comparison to phenotypic DST, the pyrosequencing method demonstrated high specificity (100%) and sensitivity (94.6%) for detection of multidrug-resistant M. tuberculosis as well as high specificity (99.3%) and sensitivity (86.9%) for detection of extensively drug-resistant M. tuberculosis . The short turnaround time combined with multilocus sequencing of several isolates in parallel makes pyrosequencing an attractive method for drug resistance screening in M. tuberculosis .

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BackgroundThe P27-P55 (lprG-Rv1410c) operon is crucial for the survival of Mycobacterium tuberculosis, the causative agent of human tuberculosis, during infection in mice. P55 encodes an efflux pump that has been shown to provide Mycobacterium smegmatis and Mycobacterium bovis BCG with resistance to several drugs, while P27 encodes a mannosylated glycoprotein previously described as an antigen that modulates the immune response against mycobacteria. The objective of this study was to determine the individual contribution of the proteins encoded in the P27-P55 operon to the resistance to toxic compounds and to the cell wall integrity of M. tuberculosis.MethodIn order to test the susceptibility of a mutant of M. tuberculosis H37Rv in the P27-P55 operon to malachite green, sodium dodecyl sulfate, ethidium bromide, and first-line antituberculosis drugs, this strain together with the wild type strain and a set of complemented strains were cultivated in the presence and in the absence of these drugs. In addition, the malachite green decolorization rate of each strain was obtained from decolorization curves of malachite green in PBS containing bacterial suspensions.ResultsThe mutant strain decolorized malachite green faster than the wild type strain and was hypersensitive to both malachite green and ethidium bromide, and more susceptible to the first-line antituberculosis drugs: isoniazid and ethambutol. The pump inhibitor reserpine reversed M. tuberculosis resistance to ethidium bromide. These results suggest that P27-P55 functions through an efflux-pump like mechanism. In addition, deletion of the P27-P55 operon made M. tuberculosis susceptible to sodium dodecyl sulfate, suggesting that the lack of both proteins causes alterations in the cell wall permeability of the bacterium. Importantly, both P27 and P55 are required to restore the wild type phenotypes in the mutant.ConclusionsThe results clearly indicate that P27 and P55 are functionally connected in processes that involve the preservation of the cell wall and the transport of toxic compounds away from the cells.

Alternative, rapid methods for DST are cost-effective and should be considered for use by national tuberculosis programs in middle-income countries.