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

Extrapulmonary tuberculosis (EPTB) accounts for more than 20% of tuberculosis (TB) cases. Xpert MTB/RIF (Xpert) (Cepheid, Sunnyvale, CA, USA) is a fully automated amplification system, for which excellent results in the diagnosis of pulmonary TB in highly endemic countries have been recently reported. We aimed to assess the performance of the Xpert system in diagnosing EPTB in a low incidence setting.We investigated with Xpert a large number of consecutive extrapulmonary clinical specimens (1,476, corresponding to 1,068 patients) including both paediatric (494) and adult samples.We found, in comparison with a reference standard consisting of combination of culture and clinical diagnosis of TB, an overall sensitivity and specificity of 81.3% and 99.8% for Xpert, while the sensitivity of microscopy was 48%. For biopsies, urines, pus and cerebrospinal fluids the sensitivity exceeded 85%, while it was slightly under 80% for gastric aspirates. It was, in contrast, lower than 50% for cavitary fluids. High sensitivity and specificity (86.9% and 99.7%, respectively) were also obtained for paediatric specimens.Although the role of culture remains central in the microbiological diagnosis of EPTB, the sensitivity of Xpert in rapidly diagnosing the disease makes it a much better choice compared to smear microscopy. The ability to rule out the disease still remains suboptimal.

Incidence data are lacking, and diagnosis remains difficult.

Mycobacterial infections represent a growing challenge for solid organ transplant recipients (SOT). The adverse effects of tuberculosis (TB) therapy present a major difficulty, due to the interactions with immunosuppressive drugs and direct drug toxicity. While TB may be donor-transmitted or community-acquired, it usually develops at a latent infection site in the recipient. Pre-transplant prevention efforts will improve transplant outcomes and avoid the complications associated with post-transplant diagnosis and treatment. The present review and consensus manuscript is based on the updated published information and expert recommendations. The current data about epidemiology, diagnosis, new regimens for the treatment of latent TB infection (LTBI), the experience with rifamycins for the treatment of active TB in the post-transplant period and the experience with isoniazid for LTBI in the liver transplant population, are also reviewed. We attempt to provide useful recommendations for each transplant period and problem concerning mycobacterial infections in SOT recipients.

Mycobacteria are a group of acid-fast, aerobic, slow-growing organisms whose genus includes more than 90 different species. The causative agents of tuberculosis (TB), which is currently considered a global emergency, with more than 2 million people dying every year and 8 million new cases, belong to the Mycobacterium tuberculosis complex (MTB). Moreover, although of lesser public health importance, many other species referred to as nontuberculous mycobacteria (NTM) have also been associated with human disease with increasing frequency worldwide (65). As MTB is highly infectious for humans, it is of paramount importance that TB be diagnosed as early as possible to stop the spread of the disease. Active TB is currently diagnosed by conventional laboratory procedures including specimen digestion and decontamination, microscopic examination for the presence of acid-fast bacilli (AFB), isolation by culture on solid and/or liquid media, and identification and drug susceptibility testing of the recovered isolate. Because of the slow growth of mycobacteria, the above-reported laboratory procedures may require turnaround times of 3 to 4 weeks or longer.During the last decade, several molecular methods have been developed for direct detection and identification of MTB in clinical specimens. These methods, being able to potentially reduce the diagnostic time from weeks to days, have been acquiring greater and greater relevance in the field of laboratory TB diagnosis. The basic principle of any molecular diagnostic test is the detection of a specific nucleic acid sequence by hybridization to a complementary sequence, a probe, followed by detection of the hybrid. However, the sensitivity of nucleic acid probe tests that do not involve amplification is much lower than that of amplified ones. Any portion of nucleic acid can be copied by using the specific polymerase, provided that some sequence data are known for the setup of appropriate primers. In general, amplification of target nucleic acid sequences is composed of three parts: denaturation, primer annealing, and primer extension. Discovery of PCRs in 1986 made this process reiterative, leading to an exponential increase in the production of the amplified target. Soon after, alternative amplification techniques were developed and patented by companies, which used different enzymes and strategies, but they are all based on reiterative reactions. Many different amplification targets including both DNA or RNA fragments have been proposed. The target most frequently amplified in MTB is the IS6110 (31) repetitive element, of which 10 to 16 copies are present in most clinical isolates. Numerous techniques for nucleic acid extraction have been proposed, as have different types of controls for monitoring the efficacy of nucleic acid extraction and amplification procedures. Currently, the U.S. Food and Drug Administration (FDA) requires that culture (still considered the "gold standard" for TB diagnosis) must be done in conjunction with the performance of each amplification-based t...