Nontuberculous mycobacterial infection in a tertiary care center in Mexico, 2001-2017

Prescription habits and drugs accessibility for the treatment of non-tuberculous mycobacteria infections in Italy: a multicentric survey from the IRENE study group

PURPOSE

Non-tuberculous mycobacteria (NTM) account for high clinical burden, and treatment can be challenging. Moreover, accessibility of NTM medications varies across centers. These challenges may lead to unplanned therapeutic changes, discontinuations, potentially affecting patient outcomes. Aim of this survey was to evaluate the accessibility of NTM-targeting drugs in Italy (with a particular focus on clofazimine) in centers associated with the IRENE Registry, a collaborative network of healthcare professionals.

METHODS

A cross-sectional, internet-based, questionnaire-survey on the use and availability of clofazimineand other NTM-targeting drugs was sent to 88 principal investigators of the IRENE network in Italyin 2020. The questionnaires were designed with closed-ended and open-ended questions and distributed using the SurveyMonkey® platform.

RESULTS

The surveys underscore the more frequent involvement of pulmonologists (42%) and infectious disease specialists (34%) in NTM treating strategies. Respondents were distributed across 18 out of20 Italian regions, with a significant concentration in the north, encompassing university hospitalsand outpatient clinics. Molecular testing is available in 40% of the involved centers, while phenotypic in 30% of the centers. Centers have a multidisciplinary team and an appointed pharmacy service for NTM drugs distribution in 10 and 75% of the cases, respectively. Substantial variability was observed in drug availability and accessibility, drug regimen composition, and drug dosage, particularly for medications like clofazimine.

CONCLUSIONS

This study shows the high heterogeneity of anti-NTM drug availability in Italy and prompts toward a harmonization in antibiotic prescription and access; it also emphasizes the challenges in determining the optimal therapeutic strategies for treating NTM-infections.

The role of mycobacteremia screening in enhancing non-tuberculous mycobacteria detection in hospitalized persons with HIV

Among hospitalized severely immunocompromised persons with HIV (PWH), non-tuberculous mycobacteria (NTM) may be under-diagnosed due to non-specific symptoms undifferentiable with other opportunistic infections. To evaluate the prevalence of NTM mycobacteremia and how screening for mycobacteremia assistant with identification of NTM infections, this study retrospectively analyzed 1,136 hospitalized PWH with CD4 counts <200 cells/μL, who underwent mycobacteremia screening at a tertiary hospital in Nanjing, China, between July 2018 and December 2023. The prevalence of non-tuberculous mycobacteremia was 5.8% (95% CI, 4.6-7.3%), with a higher prevalence of 8.6% (95% CI, 6.7-10.9%) in patients with CD4 counts <50 cells/μL, compared to 1.4% (95% CI, 0.6-3.0%) in those with CD4 counts ≥50 cells/μL. Mycobacterium avium complex (MAC) was the predominant pathogen, representing 95% (95% CI, 86.7-98.3%) of positive blood cultures, though it accounted for only 66.2% (95% CI, 54.3-76.3%) of NTM species isolated from respiratory samples. The sensitivity of mycobacterial blood cultures (MBC) in diagnosing all culture-proven NTM infections was 63.9% (95% CI, 54.0-72.8%), increasing to 75.7% (95% CI, 64.8-84.0%) in patients with CD4 counts <50 cells/μL. Notably, mycobacteremia served as the sole microbiological evidence in approximately 25% of all culture-proven NTM infections during initial hospitalization, where other specimen sources failed to yield conclusive evidence. These findings underscore the importance of mycobacteremia screening in improving the detection of NTM infections among severely immunocompromised hospitalized patients, especially those with CD4 counts <50 cells/μL, and highlight the value of incorporating MBC into diagnostic protocols to enhance clinical management of these high-risk individuals.

Clinical Characteristics and Outcomes of Extrapulmonary Nontuberculous Mycobacterial Infections in a Tertiary-Care Hospital: A Retrospective Study

Background/Objectives: The incidence of nontuberculous mycobacterial (NTM) infections has increased globally; however, the clinical manifestations and optimal treatment strategies for extrapulmonary NTM infections remain poorly defined. This study assessed the clinical manifestations and treatment outcomes of extrapulmonary NTM infections. Methods: Data from adult patients with suspected extrapulmonary NTM infections at a tertiary-care hospital from 2009-2022 were categorized into NTM disease and isolation groups. Diagnosis of NTM disease relied on stringent criteria, whereas isolation required NTM isolation without meeting the criteria for infection. Results: Among 75 patients evaluated, 32 (42%) were diagnosed with NTM disease and 43 (57%) with NTM isolation. History of immunosuppressant use within the past 3 months (p = 0.070) and injection (p = 0.001) were more frequent in the disease group. The median interval from symptom onset to evaluation was 106.6 and 20 days in the disease and isolation groups, respectively. The prevalence of positive NTM polymerase chain reaction results (36.4%, p = 0.003) and acid-fast bacillus staining (39.1%, p < 0.001) was significantly higher in the disease group than in the isolation group. Mycobacterium intracellulare (21.9%), M. abscessus (15.6%), M. chelonae (9.4%), and M. fortuitum complex (9.4%) were the most frequently identified species. Of the 27 patients in the disease group who received treatment, 13 improved, four experienced treatment failure, seven were lost to follow-up, and three died during treatment, with one death directly attributable to NTM disease. Conclusions: NTM disease exhibits a spectrum of clinical manifestations. Accurate diagnosis is crucial for initiating effective treatment.

Drugs for treating infections caused by non-tubercular mycobacteria: a narrative review from the study group on mycobacteria of the Italian Society of Infectious Diseases and Tropical Medicine

BACKGROUND

Non-tuberculous mycobacteria (NTM) are generally free-living organism, widely distributed in the environment, with sporadic potential to infect. In recent years, there has been a significant increase in the global incidence of NTM-related disease, spanning across all continents and an increased mortality after the diagnosis has been reported. The decisions on whether to treat or not and which drugs to use are complex and require a multidisciplinary approach as well as patients' involvement in the decision process.

METHODS AND RESULTS

This review aims at describing the drugs used for treating NTM-associated diseases emphasizing the efficacy, tolerability, optimization strategies as well as possible drugs that might be used in case of intolerance or resistance. We also reviewed data on newer compounds highlighting the lack of randomised clinical trials for many drugs but also encouraging preliminary data for others. We also focused on non-pharmacological interventions that need to be adopted during care of individuals with NTM-associated diseases CONCLUSIONS: Despite insufficient efficacy and poor tolerability this review emphasizes the improvement in patients' care and the needs for future studies in the field of anti-NTM treatments.

Draft genome sequences of 12 Mycolicibacterium fortuitum isolates from human pulmonary infections in Veracruz, Mexico

Mycolicibacterium fortuitum, a fast-growing nontuberculous mycobacterium, is a significant pathogen in healthcare-associated infections, encompassing skin, soft tissue, and pulmonary diseases. In this study, we present draft genome sequences from 12 M. fortuitum strains isolated from sputum samples from patients diagnosed with pulmonary infections in Mexico.

Global Epidemiology of Nontuberculous Mycobacterial Pulmonary Disease: A Review

Nontuberculous mycobacterial (NTM) isolation and pulmonary disease (NTM-PD) have continued to increase in most regions of the world, driven mainly by Mycobacterium avium. Single-center studies also support increasing trends as well as a persistent burden of undiagnosed NTM among persons suspected of having tuberculosis (TB), in countries with moderate-to-high TB prevalence. Cumulative exposure to water and soil presents an increased risk to susceptible hosts, and trace metals in water supply are recently recognized risk factors. Establishing standard case definitions for subnational and national surveillance systems with mandatory notification of NTM-PD are needed to allow comparisons within and across countries and regions.

Investigation of a Mycobacterium fortuitum catheter-related bloodstream infection in an oncology unit

We describe a case of healthcare-associated bloodstream infection due to Mycobacterium fortuitum. Whole-genome sequencing showed that the same strain was isolated from the shared shower water of the unit. Nontuberculous mycobacteria frequently contaminate hospital water networks. Preventative actions are needed to reduce the exposure risk for immunocompromised patients.

Bloodstream infections with rapidly growing nontuberculous mycobacteria

Background

Bloodstream infections (BSI) with rapidly growing mycobacteria (RGM) resulted in recent nosocomial outbreaks predominantly in immunocompromised patients. A little is known about the clinical implications of RGM BSI with different species.

Methods

We conducted a multicenter retrospective cohort study of patients with RGM BSI from November 2011 to December 2020. Demographic data, clinical presentation, laboratory and radiographic findings and microbiological characteristics were used to tabulate descriptive statistics. We performed a comparative analysis of patients with BSI due to Mycobacterium abscessus complex (MABC) vs. other RGM.

Results

We identified 32 patients with positive blood cultures for RGM, 4/32 (12.5%) were considered to have unclear significance. The most common source for RGM BSI was intravascular catheters (14/28, 50%). Compared to other sources, patients with catheter-related bloodstream infection (CRBSI) received a shorter course of antimicrobial therapy (median [IQR]: one month [0.37–2.25] vs. six months [2–12]), (P = 0.01). The most common species isolated were MABC (12/28, 42.9%), followed by Mycobacterium fortuitum group (6/28, 21.4%) and Mycobacterium chelonae (6/28, 21.4%). Compared to other RGM, MABC BSI was more likely to be secondary to skin and soft tissue infection, associated with longer hospital stay (P = 0.04) and higher death rates despite a higher number of antimicrobial agents used for empirical and directed therapy per patient.

Conclusion

MABC BSI is associated with an overall more resistant profile, longer hospital stay, and higher death rate despite a more aggressive therapy approach.

Time to Positive Culture Detection Predicts Mycobacterium avium Pulmonary Disease Severity and Treatment Initiation

RATIONALE

Additional biomarkers are needed to guide initiation of treatment for Mycobacterium avium pulmonary disease (Mav-PD). Time to positive sputum culture detection (TTP) may offer potential prognostic and monitoring value.

OBJECTIVE

To determine whether TTP is associated with infection severity and early treatment response in Mav-PD?

METHODS

We undertook a retrospective cohort study of patients with ≥2 sputum cultures positive for M. avium, an 'index' sputum M. avium isolate during 2015-2019, a CT scan within 6 months, and no treatment for ≥6 months prior to index sputum. TTP was estimated from the date of laboratory receipt of the specimen to the date of culture positivity confirmation. TTP was tested for association with markers of infection severity (Mav-PD, bronchiectasis, cavitary disease, treatment initiation by 3 and 6 months, AFB smear) and treatment response using Mann-Whitney U, Spearman's Correlation Coefficient, and Wilcoxon signed-rank tests. We explored a threshold TTP that could identify significant M. avium disease.

RESULTS

We included 125 patients with mean (SD) age 68.5 (12.5) years and 65% fulfilled disease criteria. Median TTP was 12 days (IQR 10-15; range 6-44). TTP and AFB smear grade were negatively correlated (ρ -0.58, p<0.001). TTP was associated with NTM disease (p=0.03), AFB smear positivity (p<0.001), and treatment initiation by three (p=0.01) and six (p=0.03) months. A threshold TTP of ≤10 days was associated with Mav-PD (80.6% vs 58.4%; ð (95%CI) 22.1 (5.6-38.6)%,p=0.02), AFB smear positivity (83.3% vs 20.2%, ð (95%CI) 63.1(48.3-77.9)%, p<0.001), treatment by three (38.9% vs 13.5%; ð (95%CI) 25.4 (8.0-42.8)%, p=0.003) and six (47.2% vs 19.1%; ð (95%CI) 28.1 (9.9-46.4)%,p=0.003) months. After three and six months of treatment, the median (IQR) change in TTP was +8 (1-undefined; p<0.001) and +7 (0-undefined; p=0.001) days respectively.

CONCLUSION

TTP is associated with bacterial burden and infection severity and increases in response to treatment. A threshold of ≤10 days may be useful in predicting significant Mav-PD. As a readily available biomarker, further exploration of TTP is imperative.

Mycobacterial biofilms as players in human infections: a review

The role of biofilms in pathogenicity and treatment strategies is often neglected in mycobacterial infections. In recent years, the emergence of nontuberculous mycobacterial infections has necessitated the development of novel prophylactic strategies and elucidation of the mechanisms underlying the establishment of chronic infections. More importantly, the question arises whether members of the Mycobacterium tuberculosis complex can form biofilms and contribute to latent tuberculosis and drug resistance because of the long-lasting and recalcitrant nature of its infections. This review discusses some of the molecular mechanisms by which biofilms could play a role in infection or pathological events in humans.

Endophthalmitis caused by Mycobacterium houstonense: case report

BACKGROUND

Mycobacterium houstonense is rapidly growing mycobacteria (RGM) that belongs to M. fortuitum group. So far, there have been few associated reports of human diseases induced by M. houstonense worldwide.

CASE PRESENTATION

We present a delayed-onset postoperative endophthalmitis caused by M. houstonense after glaucoma drainage implant (GDI) surgery. The ocular infection lasted for 2 months without appropriate treatment that developed into endophthalmitis and the patient underwent an emergency enucleation.

CONCLUSION

Implant erosion and a delay in diagnosis of ocular infection could lead to irreversible damage as observed in our case. Ophthalmologists should be alert for ocular RGM infection, and prompt laboratory diagnosis with initiation of effective multidrug therapy might prevent loss of vision.

Diagnostic performance of real time PCR and MALDI-TOF in the detection of nontuberculous mycobacteria from clinical isolates

This study aimed to evaluate the performance of real-time PCR (qPCR) and MALDI-TOF for accurate and timely detection of nontuberculous mycobacterium (NTM) from clinical isolates. We collected fifty NTM suspected Mycobacteria Growth Indicator Tube (MGIT) cultures and analysed the diagnostic performance of qPCR and VITEK MS using Line Probe Assay (LPA) GenoType CM (Common Mycobacteria) as gold standard. The qPCR assays targeting 16S rRNA, ITS and IS6110 genes were developed for the identification of NTM and Mycobacterium tuberculosis complex (MTBC). LPA GenoType CM, a PCR technique targeting 23S rRNA gene, followed by reverse hybridization and line probe technology identified 90% of Mycobacterium species including M. fortuitum (16%,n = 8), M. intracellulare (10%,n = 5), M. gordonae (10%,n = 5), M. xenopi (4%,n = 2), M. scrofulaceum (4%,n = 2), Mycobacterium additional species (AS) (32%,n = 16) and MTBC (14%,n = 7), qPCR detected 80% of Mycobacterium species (NTM, 66% (n = 33) and MTBC, 14% (n = 7)) and MALDI-TOF, 52% (M. fortuitum (12%,n = 6), M. intracellulare (10%, n = 5), M. simiae (8%,n = 4), M. gordonae (8%,n = 4), and MTBC (14%,n = 7)). Sensitivity of qPCR and MALDI-TOF was 88.9% and 57.8%, respectively with 100% specificity. The combination of qPCR and MALDI-TOF remains an appropriate test for timely diagnosis of Mycobacterium species. This may eventually assist to detect the cases that may have been missed by phenotypic tests and enhance the NTM diagnosis capability to improve effective patient management.