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

The genetic heterogeneity of the nomenspecies Enterobacter cloacae is well known. Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter dissolvens, Enterobacter hormaechei, Enterobacter kobei, and Enterobacter nimipressuralis are closely related to it and are subsumed in the so-called E. cloacae complex. DNA-DNA hybridization studies performed previously identified at least five DNA-relatedness groups of this complex. In order to analyze the genetic structure and the phylogenetic relationships between the clusters of the nomenspecies E. cloacae, 206 strains collected from 22 hospitals, a veterinarian, and an agricultural center in 11 countries plus all 13 type strains of the genus and reference strain CDC 1347-71 R were examined with a combination of sequence and PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of the three housekeeping genes hsp60, rpoB, and hemB as well as ampC, the gene of a class C ␤-lactamase. Based on the neighbor-joining tree of the hsp60 sequences, 12 genetic clusters (I to XII) and an unstable sequence crowd (xiii) were identified. The robustness of the genetic clusters was confirmed by analyses of rpoB and hemB sequences and ampC PCR-RFLPs. Sequence crowd xiii split into two groups after rpoB analysis. Only three strains formed a cluster with the type strain of E. cloacae, indicating that the minority of isolates identified as E. cloacae truly belong to the species; 13% of strains grouped with other type strains of the genus, suggesting that the phenotypes of these species seem to be more heterogeneous than so far believed. Three clusters represented 70% of strains, but none of them included a type or reference strain. The genetic clustering presented in this study might serve as a framework for future studies dealing with taxonomic, evolutionary, epidemiological, or pathogenetic characteristics of bacteria belonging to the E. cloacae complex.Enterobacter cloacae has become increasingly important as a nosocomial pathogen, accounting for up to 5% of hospitalacquired septicemias, 5% of nosocomial pneumonias, 4% of nosocomial urinary tract infections, and 10% of postsurgical peritonitis cases (18,35,39). Besides its clinical significance, E. cloacae plays an important role as a pathogen in plants (2, 34) and insects (15) and is ubiquitous in the terrestrial and aquatic environments (22). This diversity of habitats is mirrored by the genetic variety of the nomenspecies E. cloacae, which has been demonstrated in several studies by biotyping and serotyping (16, 47), ribotyping and phage typing (46), pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) (18), and internal transcribed spacer-PCR and random amplification of polymorphic DNA (RAPD)-PCR (6). The 16S ribosomal DNA (rDNA) sequences of E. cloacae did not form a coherent cluster but built a patchy tree, in which the clusters of E. cloacae strains interfused with those of Enterobacter aerogenes, Escherichia coli, Citrobacter species, and Leclercia species. This refl...

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The objectives of this study were to investigate the origin of highly discordant rifampin (rifampicin) (RMP) drug susceptibility test results obtained for Mycobacterium tuberculosis strains during proficiency testing. Nine Supra-National Tuberculosis Reference Laboratories tested the RMP susceptibilities of 19 selected M. tuberculosis strains, using standard culture-based methods. The strains were classified as definitely resistant (R) (n ‫؍‬ 6) or susceptible (S) (n ‫؍‬ 2) or probably resistant (PR) (n ‫؍‬ 8) or susceptible (PS) (n ‫؍‬ 3) based on rpoB mutations and treatment outcome. All methods yielded a susceptible result for the two S and three PS strains lacking an rpoB mutation and a resistant result for one R strain with a Ser531Leu mutation and one PR strain with a double mutation. Although the remaining 12 R and PR strains had rpoB mutations (four Asp516Tyr, three Leu511Pro, two Leu533Pro, one each His526Leu/Ser, and one Ile572Phe), they were all susceptible by the radiometric Bactec 460TB or Bactec 960 MGIT methods. In contrast, only one was susceptible by the proportion method on Löwenstein-Jensen medium and two on Middlebrook 7H10 agar. Low-level but probably clinically relevant RMP resistance linked to specific rpoB mutations is easily missed by standard growth-based methods, particularly the automated broth-based systems. Further studies are required to confirm these findings, to determine the frequency of these low-level-resistant isolates, and to identify technical improvements that may identify such strains.The prevalence of multidrug-resistant (MDR) tuberculosis (TB) is rising globally, posing a serious threat to TB control. (25) MDR TB does not respond to treatment with first-line drugs, (3), and its management using second-line drugs has not yet been properly organized by most control programs (25). Although MDR TB is defined as resistance to at least isoniazid and rifampin (rifampicin) (RMP), the key determinant for treatment failure is RMP resistance. Detection of RMP resistance has thus been proposed as a proxy for MDR TB diagnosis, as well as for epidemiological monitoring (14,20,24). RMP drug susceptibility testing (DST), by conventional methods based on growth as well as by newer genetic techniques, is generally considered the most reliable (1, 8). Highly consistent results were obtained during the early proficiency testing (PT) rounds among the Supra-National TB Reference Laboratories (SRLS) of the World Health Organization (WHO)/International Union against Tuberculosis and Lung Disease network. Consequently, Laszlo et al. proposed a 99% efficiency target for RMP DST by the SRLs (8). However, 15 of 240 quality control strains (6.2%) distributed from 1999 to 2007 yielded less than 80% agreement for RMP resistance among the SRLs, insufficient for a judicial result. The panels were designed to contain approximately 50% resistance to all first-line TB drugs in various combinations. This precondition resulted in overrepresentation of rare profiles. The SRLs employed one of the four recogni...

Linezolid is used to treat patients with multidrug-resistant (MDR)/extensively drugresistant (XDR)-tuberculosis (TB) cases, although clinical data on its safety, tolerability and efficacy are lacking.We performed a retrospective, nonrandomised, unblinded observational study evaluating the safety and tolerability of linezolid at 600 mg q.d. or b.i.d. in MDR/XDR-TB treatment in four European countries. Efficacy evaluation compared end-points of 45 linezolid-treated against 110 linezolid-nontreated cases.Out of 195 MDR/XDR-TB patients, 85 were treated with linezolid for a mean of 221 days. Of these, 35 (41.2%) out of 85 experienced major side-effects attributed to linezolid (anaemia, thrombocytopenia and/or polyneuropathy), requiring discontinuation in 27 (77%) cases. Most side-effects occurred after 60 days of treatment. Twice-daily administration produced more major side-effects than once-daily dosing (p50.0004), with no difference in efficacy found. Outcomes were similar in patients treated with/without linezolid (p50.8), although linezolid-treated cases had more first-line (p50.002) and second-line (p50.02) drug resistance and a higher number of previous treatment regimens (4.5 versus 2.3; p50.07).Linezolid 600 mg q.d. added to an individualised multidrug regimen may improve the chance of bacteriological conversion, providing a better chance of treatment success in only the most complicated MDR/XDR-TB cases. Its safety profile does not warrant use in cases for which there are other, safer, alternatives.