PLoS One

The first objective of this study was to determine the GenoType NTM-DR assay performance for subspecies identification in Mycobacterium abscessus complex isolates. The second objective was to evaluate the GenoType NTM-DR assay ability to detect clarithromycin and amikacin resistance in M. abscessus complex isolates compared with drug susceptibility testing (DST) and PCR sequencing of the erm(41), rrl and rrs genes. The concordance between the GenoType NTM-DR and MLST results concerning subspecies identification was 100%. The wild type and mutated alleles of the rrl and rrs genes were detected by the GenoType NTM-DR assay and PCR sequencing with 100% (115/115) agreement. Similarly, 100% concordance between GenoType NTM-DR and DST was observed for clarithromycin and amikacin testing. Sensitivity for the detection of clarithromycin and amikacin resistance was 100%. The GenoType NTM-DR assay provides a robust and complementary tool to the gold standard methods (MLST and broth microdilution) for subspecies identification and drug resistance detection

Infection pulmonaire a Mycobacterium abscessus sensu lato chez des patients exempts de mucoviscidose.

International audienceInfection with Mycobacterium abscessus sensu lato is uncommon in patients without cystic fibrosis. We are interested in these patients and have collected cases in Finistère between 2007 and 2011. Four patients met the infection criteria recommended by the American Thoracic Society in 2007. Among them, all had Aspergillus spp. in sputum, 3 had gastroesophageal reflux and two had the criteria for allergic bronchopulmonary aspergillosis. We identified Mycobacterium massiliense in the single patient in our series whose therapeutic outcome was successful. By comparing these data with those in the literature, we believe that the search for allergic bronchopulmonary aspergillosis and gastroesophageal reflux is necessary in these patients and that species identification is essential for prognosis

Bone infections caused by Gemella haemolysans

International audienc

Lactobacilli intra-tracheal administration protects from Pseudomonas aeruginosa pulmonary infection in mice - a proof of concept

WOS:000501544400007International audienceThe spreading of antibiotic resistance is a major public health issue, which requires alternative treatments to antibiotics. Lactobacilli have shown abilities to prevent pneumonia in clinical studies when given by oral route, certainly through the gut-lung axis involvement. Rationally, respiratory administration of lactobacilli has been developed and studied in murine model, to prevent from respiratory pathogens. It allows a direct effect of probiotics into the respiratory system. To our knowledge, no study has ever focused on the effect of probiotic intra-respiratory administration to prevent from Pseudomonas aeruginosa (PA) pneumonia, a major respiratory pathogen associated with high morbidity rates. In this study, we evaluated the beneficial activity of three Lactobacillus strains (Lactobacillus fermentum K.C6.3.1E, Lactobacillus zeae Od.76, Lactobacillus paracasei ES.D.88) previously screened by ourselves and known to be particularly efficient in vitro in inhibiting PAO1 virulence factors. Cytotoxic assays in alveolar epithelial cell line A549 were performed, followed by the comparison of two lactobacilli prophylactic protocols (one or two administrations) by intra-tracheal administration in a C57BL/6 murine model of PA pneumonia. A549 cells viability was improved from 23 to 75% when lactobacilli were administered before PAO1 incubation, demonstrating a protective effect (P\textless0.001). A significant decrease of 2 log of PAO1 was observed 4 h after PAO1 instillation (3x 10(6) cfu/mouse) in both groups receiving lactobacilli (9x 10(6) cfu/mouse) compared to PAO1 group (P\textless0.05). One single prophylactic administration of lactobacilli significantly decreased the secretion by 50% in bronchoalveolar lavages of interleukin (IL)-6 and tumour necrosis factor-a compared to PAO1. No difference of secretion was observed for the IL-10 secretion, whatever the prophylactic study design. This is the first study highlighting that direct lung administration of Lactobacillus strains protect against PA pneumonia. Next step will be to decipher the mechanisms involved before developing this novel approach for human applications

How to: identify non-tuberculous Mycobacterium species using MALDI-TOF mass spectrometry.

The implementation of MALDI-TOF MS for microorganism identification has changed the routine of the microbiology laboratories as we knew it. Most microorganisms can now be reliably identified within minutes using this inexpensive, user-friendly methodology. However, its application in the identification of mycobacteria isolates has been hampered by the structure of their cell wall. Improvements in the sample processing method and in the available database have proved key factors for the rapid and reliable identification of non-tuberculous mycobacteria isolates using MALDI-TOF MS. The main objective is to provide information about the proceedings for the identification of non-tuberculous isolates using MALDI-TOF MS and to review different sample processing methods, available databases, and the interpretation of the results. Results from relevant studies on the use of the available MALDI-TOF MS instruments, the implementation of innovative sample processing methods, or the implementation of improved databases are discussed. Insight about the methodology required for reliable identification of non-tuberculous mycobacteria and its implementation in the microbiology laboratory routine is provided. Microbiology laboratories where MALDI-TOF MS is available can benefit from its capacity to identify most clinically interesting non-tuberculous mycobacteria in a rapid, reliable, and inexpensive manner

Inducible and Acquired Clarithromycin Resistance in the Mycobacterium abscessus Complex

PurposeClarithromycin was considered the cornerstone for the treatment of Mycobacterium abscessus complex infections. Genetic resistance mechanisms have been described and many experts propose amikacin as an alternative. Nevertheless, clarithromycin has several advantages; therefore, it is necessary to identify the non-functional erm(41) allele to determine the most suitable treatment. The aims of this study were to characterize the molecular mechanisms of clarithromycin resistance in a collection of Mycobacterium abscessus complex isolates and to verify the relationship between these mechanisms and the antibiogram.Materials and methodsClinical isolates of M. abscessus complex (n = 22) from 16 patients were identified using four housekeeping genes (rpoB, secA1, sodA and hsp65), and their genetic resistance was characterized by studying erm(41) and rrl genes. Nine strains were recovered from the clinical isolates and subjected to E-test and microdilution clarithromycin susceptibility tests, with readings at 3, 7 and 14 days.ResultsWe classified 11/16 (68.8%) M. abscessus subsp. abscessus, 4/16 (25.0%) M. abscessus subsp. bolletii, and 1/16 (6.3%) M. abscessus subsp. massiliense. T28 erm(41) allele was observed in 8 Mycobacterium abscessus subps. abscessus and 3 Mycobacterium abscessus subsp. bolletii. One strain of M. abscessus subsp. bolletii had an erm(41) gene truncated and was susceptible to clarithromycin. No mutations were observed in rrl gene first isolates. In three patients, follow-up of initial rrl wild-type strains showed acquired resistance.ConclusionsMost clinical isolates of M. abscessus complex had inducible resistance to clarithromycin and total absence of constitutive resistance. Our findings showed that the acquisition of resistance mutations in rrl gene was associated with functional and non-functional erm(41) gene. Caution is needed when using erm(41) sequencing alone to identify M. abscessus subspecies. This study reports an acquired mutation at position 2057 of rrl gene, conferring medium-low clarithromycin constitutive resistance