Management of patients with pulmonary mycobacteriosis in France: a multicenter retrospective cohort study.

BACKGROUND: Recent studies report very low adherence of practitioners to ATS/IDSA recommendations for the treatment of nontuberculous mycobacteria pulmonary disease (NTM-PD), as well as a great variability of practices. Type of management could impact prognosis. METHODS: To evaluate management and prognosis of patients with NTM-PD cases with respect to ATS recommendations, we conducted a multicenter retrospective cohort study (18 sentinel sites distributed throughout France), over a period of six years. We collected clinical, radiological, microbiological characteristics, management and outcome of the patients (especially death or not). RESULTS: 477 patients with NTM-PD were included. Respiratory comorbidities were found in 68% of cases, tuberculosis sequelae in 31.4% of patients, and immunosuppression in 16.8% of cases. The three most common NTM species were Mycobacterium avium complex (60%), M. xenopi (20%) and M. kansasii (5.7%). Smear-positive was found in one third of NTM-PD. Nodulobronchiectatic forms were observed in 54.3% of cases, and cavitary forms in 19.1% of patients. Sixty-three percent of patients were treated, 72.4% of patients with smear-positive samples, and 57.5% of patients with smear-negative samples. Treatment was in adequacy with ATS guidelines in 73.5%. The 2-year mortality was 14.4%. In the Cox regression, treatment (HR = 0.51), age (HR = 1.02), and M. abscessus (3.19) appeared as the 3 significant independent prognostic factors. CONCLUSION: These findings highlight the adequacy between French practices and the ATS/IDSA guidelines. Treatment was associated with a better survival.

Evaluation of the SLOMYCO Sensititre(®) panel for testing the antimicrobial susceptibility of Mycobacterium marinum isolates.

BACKGROUND: The agar dilution method is currently considered as the reference method for Mycobacterium marinum drug susceptibility testing (DST). As it is time-consuming, alternative methods, such as the E-test, were evaluated for M. marinum DST, but without success. The SLOMYCO Sensititre(®) panel, recently commercialized by TREK Diagnostic Systems (Cleveland, OH), can be used for DST in slow-growing mycobacteria and for antimicrobial agents recommended by the Clinical and Laboratory Standards Institute (CLSI) for M. marinum DST. The main goal of this work was to evaluate the SLOMYCO Sensititre(®) panel method for DST in M. marinum isolates from human patients and fish relative to the reference agar dilution method. METHODS/RESULTS: The reproducibility of the minimum inhibitory concentration (MIC) determination (±1 log2 dilution) was very good for both the agar dilution method and SLOMYCO Sensititre(®) panel (>90 % agreement). The percentage essential agreement between methods varied, depending on the drug: between 97 and 75 % for ciprofloxacin, moxifloxacin, linezolid, isoniazid, clarithromycin, amikacin, rifabutin and rifampin, 74 % for trimethoprim, 72 % for doxycycline, 70 % for sulfamethoxazole, 59 % for streptomycin, 33 % for ethambutol and only 2.2 % for ethionamide. When the agar dilution and SLOMYCO Sensititre(®) panel results were converted into interpretive criteria, the category agreement was 100 % for amikacin, ciprofloxacin, clarithromycin, moxifloxacin, rifabutin, sulfamethoxazole and trimethoprim, 98 % for ethambutol and 96 % for rifampin and no agreement for doxycycline. CONCLUSIONS: The SLOMYCO Sensititre(®) panel method could provide a potential alternative to the reference agar dilution method, when DST in M. marinum is required, except for doxycycline.

A French multicentric study and review of pulmonary Nocardia spp. in cystic fibrosis patients.

Some bacterial species recovered from the airways of cystic fibrosis (CF) patients are indisputably associated with lung infections, whereas the clinical relevance of others, such as Nocardia spp., remains unclear. Sixteen French CF cases of colonization/infection with Nocardia spp. were reviewed in order to evaluate the epidemiology, the clinical impact and the potential treatment of these bacteria, and results were compared to those of the literature. Five Nocardia species were identified, Nocardia cyriacigeorgica being the major species (50 % of cases). At first isolation, Nocardia was the sole pathogen recovered in six patients. Seven patients presented pulmonary exacerbation. For 12 patients, antimicrobial treatment against Nocardia was started immediately, mainly based on cotrimoxazole (6 of the 12 cases). In this study, we highlight the heterogeneity of the clinical management of Nocardia spp. in CF. Guidelines for the clinical management of Nocardia infections in CF patients are proposed.

Genetic diversity and population structure of Mycobacterium marinum: new insights into host and environmental specificities.

Mycobacterium marinum causes a systemic tuberculosis-like disease in fish and skin infections in humans that can spread to deeper structures, resulting in tenosynovitis, arthritis, and osteomyelitis. However, little information is available concerning (i) the intraspecific genetic diversity of M. marinum isolated from humans and animals; (ii) M. marinum genotype circulation in the different ecosystems, and (iii) the link between M. marinum genetic diversity and hosts (humans and fish). Here, we conducted a genetic study on 89 M. marinum isolates from humans (n = 68) and fish (n = 21) by using mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing. The results show that the M. marinum population is genetically structured not only according to the host but also according to the ecosystem as well as to tissue tropism in humans. This suggests the existence of different genetic pools in the function of the biological and ecological compartments. Moreover, the presence of only certain M. marinum genotypes in humans suggests a different zoonotic potential of the M. marinum genotypes. Considering that the infection is linked to aquarium activity, a significant genetic difference was also detected when the human tissue tropism of M. marinum was taken into consideration, with a higher genetic polymorphism in strains isolated from patients with cutaneous forms than from individuals with deeper-structure infection. It appears that only few genotypes can produce deeper infections in humans, suggesting that the immune system might play a filtering role.

B cells response directed against Cut4 and CFP21 lipolytic enzymes in active and latent tuberculosis infections.

BACKGROUND: Better understanding of the immune response directed against Mycobacterium tuberculosis (Mtb) is critical for development of vaccine strategies and diagnosis tests. Previous studies suggested that Mtb enzymes involved in lipid metabolism, are associated with persistence and/or reactivation of dormant bacilli. METHODS: Circulating antibodies secreting cells (ASCs), memory B cells, and antibodies directed against Cut4 (Rv3452) and CFP21 (Rv1984c) antigens were explored in subjects with either active- or latent-tuberculosis (LTB), and in Mtb-uninfected individuals. RESULTS: Circulating anti-Cut4 ASCs were detected in 11/14 (78.6%) subjects from the active TB group vs. 4/17 (23.5%) from the LTB group (p = 0.001). Anti-CFP21 ASCs were found in 11/14 (78.6%) active TB vs. in 5/17 (29.4%) LTB cases (p = 0.01). Circulating anti-Cut4 and anti-CFP21 ASCs were not detected in 38 Mtb uninfected controls. Memory B cells directed against either Cut4 or CFP21 were identified in 8/11 (72.7%) and in 9/11 (81.8%) subjects with LTB infection, respectively, and in 2/6 Mtb uninfected individuals (33.3%). High level of anti-Cut4 and anti-CFP21 IgG were observed in active TB cases. CONCLUSION: Circulating IgG SCs directed against Cut4 or CFP21 were mostly detected in patients presenting an active form of the disease, suggesting that TB reactivation triggers an immune response against these two antigens.

High IFN-γ Release and Impaired Capacity of Multi-Cytokine Secretion in IGRA Supernatants Are Associated with Active Tuberculosis.

Interferon gamma (IFN-γ) release assays (IGRAs) detect Mycobacterium tuberculosis (Mtb) infection regardless of the active (ATB) or latent (LTBI) forms of tuberculosis (TB). In this study, Mtb-specific T cell response against region of deletion 1 (RD1) antigens were explored by a microbead multiplex assay performed in T-SPOT TB assay (T-SPOT) supernatants from 35 patients with ATB and 115 patients with LTBI. T-SPOT is positive when over 7 IFN-γ secreting cells (SC)/250 000 peripheral blood mononuclear cells (PBMC) are enumerated. However, over 100 IFN-γ SC /250 000 PBMC were more frequently observed in the ATB group compared to the LTBI group. By contrast, lower cytokine concentrations and lower cytokine productions relative to IFN-γ secretion were observed for IL 4, IL-12, TNF-α, GM-CSF, Eotaxin and IFN-α when compared to LTBI. Thus, high IFN-γ release and low cytokine secretions in relation with IFN-γ production appeared as signatures of ATB, corroborating that multicytokine Mtb-specific response against RD1 antigens reflects host capacity to contain TB reactivation. In this way, testing cytokine profile in IGRA supernatants would be helpful to improve ATB screening strategy including immunologic tests.

Mycobacterium heckeshornense tenosynovitis.

We describe the first case of tenosynovitis due to Mycobacterium heckeshornense, a mycobacterium characterized in 2000 and only incriminated in a few previous cases of infections. Molecular identification of this pathogen included 16S rRNA and hsp65 gene sequencing. M. heckeshornense may cause a wide spectrum of human infectious diseases and may be underestimated due to its phenotypic relatedness with Mycobacterium xenopi.