Nontuberculous Mycobacteria Isolates Research Articles

P-1491. Practice variations and clinical outcomes of Intravenous Aminoglycosides in Nontuberculous Mycobacterium infections at three tertiary hospitals in London, Ontario, Canada

Abstract Background The worldwide occurrence of nontuberculous Mycobacterium (NTM) infections is rising. In Canada, there is a continuing surge in infections caused by Mycobacterium avium complex (MAC). Treating NTM infections is challenging and requires multidrug regimens with antimicrobial susceptibilities to guide therapy. Generally, aminoglycosides have moderate in-vitro activity against NTM isolates. However, the synergistic effect with other antimicrobials makes it an attractive choice for clinicians, especially in the management of severe or refractory cases. The recommended duration of intravenous aminoglycosides is debatable due to side effects and the need for therapeutic monitoring. Moreover, NTMs are becoming more resistant to aminoglycosides. This study aims to assess clinical practice variations in aminoglycoside use among NTM infections in terms of duration and monitoring in London, Canada. Patient Characteristics and Clinical Presentation Methods Retrospective study reviewing the characteristics of 30 patients diagnosed with NTM infection between January 1, 2019 and December 31, 2023 in three tertiary care hospitals in London, Ontario, Canada.Table 2:NTM Susceptibility Report Results Mean age at diagnosis was 60.8 years. Seventeen (57%) were male and 13 (43%) were female. The presentations included pulmonary NTM infections in 19 (63%) and skin and soft tissue infections in four (13%). Among all identified species, MAC was the most common. Fifteen (50%) patients received IV aminoglycosides, with 7 (32%) having documented susceptibility to aminoglycosides. Duration of aminoglycoside use varied among patients, ranging from 2 to 24 weeks. Of the patients started on an IV aminoglycoside, 3 (20%) developed ototoxicity and 2 (13%) had acute kidney injury. Serum aminoglycoside levels were checked in 12 (80%), but only 7 patients (47%) had at least one audiology screen. In terms of outcomes, 7 (23%) achieved clinical cure while 9 (30%) had refractory disease, 7 (78%) of which were pulmonary. Two (57%) of the cured patients and 2 (22%) of the refractory patients had received an aminoglycoside. Aminoglycoside Use and Monitoring Conclusion Aminoglycoside use for the treatment of NTMs is variable among clinicians, mostly due to concerns for side effects and the need for consistent drug monitoring, which limits its implementation in outpatient settings. Clinical Outcomes Disclosures Lise Bondy, Assistant Professor, Pfizer: Honoraria|Viiv: Advisor/Consultant Michael Silverman, MD, FRCP, FACP, AAHIVMed, Pfizer: Grant/Research Support

P-798. Non-Tuberculosis Mycobacterial Infections at a National Cancer Institute-Designated Comprehensive Cancer Center in Florida

Abstract Background Non-tuberculous mycobacteria (NTM) are environmental organisms which become opportunistic pathogens in certain patient populations. NTM prevalence has increased globally, thought to be due to the increased diagnostic testing and availability of population-based studies. This is especially true in Florida, where we have previously documented more cases of Mycobacterium abscessus group compared to M. avium Complex (MAC) group. Current literature of NTM infections in oncology patients is minimal and represents a unique area for study. Here we present our epidemiological and clinical presentation of NTM infection cases at a National Cancer Institute-designated comprehensive cancer center.Figure 1.Patient Characteristics Methods Retrospective, Institutional Review Board-approved, single-center cohort study, of adult patients with microbiologically proven NTM infections who presented from 2020 to 2023. Demographic, laboratory, and susceptibility data were retrieved from the electronic medical record system and evaluated to show institutional patterns.Figure 2.Microbiological Characteristics for Overall Population Results Ninety-three cases of NTM infection met assessment criteria. Baseline characteristics are shown in Figure 1. A large proportion were female (71%) and white (90%). Many had a past or active cancer (80%), with skin (23%), lung (22%), and breast (13%) most prevalent. MAC (52%) and M. abscessus group (31%) were the most common NTM isolates (Figure 2). The majority were pulmonary infections (81%), with the integument accounting for most non-pulmonary sites (78%). Positive cultures were most frequently obtained via bronchoalveolar lavage (62%) followed by sputum (13%). Figure 3 offers insight into infection/culture site and cancer type stratified by organism, while susceptibility patterns are summarized in Figure 4.Figure 3.Site of Infection/Culture and Type of Cancer Stratified by Organism Conclusion NTM infections at our institution were primarily caused by MAC or M. abscessus group and were typically pulmonary in nature, isolated via bronchoalveolar lavage. Most occurred in patients with a solid tumor malignancy. Further research is needed to delineate prevalence patterns, microbiological characteristics, and treatment approaches of NTM infections in our site’s population. Susceptibility by Organism Disclosures All Authors: No reported disclosures

Evaluation of a Commercial Multiplex Real-Time PCR with Melting Curve Analysis for the Detection of Mycobacterium tuberculosis Complex and Five Nontuberculous Mycobacterial Species.

Accurate and timely diagnosis of mycobacterial infections, including Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM), is crucial for effective disease management. This study evaluated the performance of the NeoPlex TB/NTM-5 Detection Kit (NeoPlex assay, Seongnam, Republic of Korea), a multiplex real-time PCR assay that incorporates melting curve analysis, compared with the line-probe assay (LPA). The NeoPlex assay could simultaneously detect and differentiate MTBC from five other NTM species: Mycobacterium intracellulare, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium abscessus, and Mycobacterium massiliense. A total of 91 acid-fast bacillus culture-positive samples, comprising 36 MTBC and 55 NTM isolates, were collected from the Korea University Anam Hospital. The NeoPlex assay successfully detected nucleic acids in 87 of the 91 isolates (95.6%). Notably, it identified additional mycobacterial nucleic acids not detected by the LPA in eight isolates. These findings were confirmed via DNA sequencing. The assay had 100% sensitivity and specificity for M. intracellulare, M. abscessus, M. massilense, NTM, and MTBC, whereas it had 100% specificity and sensitivity of 90.9% and 75.0% for M. avium and M. kansasii, respectively. These results highlight the potential of the NeoPlex assay to enhance rapid and accurate diagnosis of mycobacterial infections, particularly in settings in which prompt treatment initiation is essential.

SQ31f is a potent non-tuberculous mycobacteria antibiotic by specifically targeting the mycobacterial F-ATP synthase.

Non-tuberculous mycobacteria (NTM) infection presents a growing global health problem and requires new antibiotics targeting enzymes that are essential for the pathogens under various metabolic conditions, with high target specificity, good solubility and with attractive combinatory potency. SQ31f was synthesized by a simplified synthesis protocol, and its effect on growth inhibition of fast- and slow-growing NTM and clinical isolates, whole-cell ATP depletion, ex vivo macrophages and its potency in combination with other antibiotics were evaluated. Molecular docking studies were employed to assess SQ31f's binding mode. We present- squaramide SQ31f as a novel anti-NTM inhibitor targeting the NTM F1FO-ATP synthase, essential for ATP formation, regulation of ATP homeostasis and proton motive force under multiple growth conditions. The potency of SQ31f in growth inhibition of fast- and slow-growing NTM and clinical isolates correlates with whole-cell ATP depletion, which is not caused by altered oxygen consumption. SQ31f's high aqueous solubility enables binding to the waterfilled cytosolic proton half channel in the subunits a-c interface of the FO domain. As presented for the fast-growing Mycobacterium abscessus, the compound is active against intracellular-residing M. abscessus. Importantly, SQ31f shows an additive effect of the anti-M. abscessus drugs clofazimine, rifabutin or amikacin, and an attractive potentiation of linezolid, clarithromycin, or the oral pair tebipenem and avibactam. SQ31f represents an attractive inhibitor to tackle the issues associated with NTM drug tolerance and toxicity. Its combinatory potency with anti-M. abscessus drugs holds potential for overcoming resistance, while also reducing intensive compound synthesis and associated costs.

A histopathological study in road-killed European badgers (Meles meles) from the English midlands with isolation of novel non-tuberculous atypical mycobacteria

European badgers (Meles meles) play an important role in the epidemiology of bovine tuberculosis (caused by Mycobacterium bovis) in England, but little is known about the prevalence of atypical mycobacteriosis. Badgers are also known to be infected by other infectious agents, and the relationship between mycobacteriosis and concomitant infections needs further investigation. Overall, 88 badger carcasses from the Midlands of England collected between July 2016-August 2017 were selected for histopathological examination based on the degree of autolysis (mild), mycobacterial culture results and a balanced sex ratio. Mycobacteria were cultured from 44 badgers, of which 31 were mycobacteria belonging to the M. tuberculosis complex (MTBC) (based on IS6110 PCR and Hsp64 and/or rRNA PCR and sequencing) and 13 were non-tuberculous atypical mycobacteria (NTM). Mycobacteria were not cultured from the remaining 44 animals. Histologically, the most common findings were silica-laden macrophages (85%), granulomas (53%), sarcocystosis (47%), nephritis (31%), portal/periportal hepatitis (26%), ulcerative dermatitis (18%). Culturable mycobacteriosis was associated with higher prevalence of granulomas (p < 0.001) and lower prevalence of hepatitis (p = 0.003). NTM (M. nonchromogenicum, M. avium complex, M. hassiacum, M. malmoense, M. vaccae.) infections were associated with granulomatous pneumonia, and M. malmoense was associated with pyogranulomatous and ulcerative dermatitis. In conclusion, this study describes, for the first time, histological lesions associated with NTM in badgers, the histomorphology of which was similar to those caused by MTBC. In addition, the negative relationship between mycobacteriosis and periportal hepatitis may indicate a complex relationship between mycobacteriosis and other diseases, as previously observed with tuberculosis.

Genomic Epidemiology of Extrapulmonary Nontuberculous Mycobacteria Isolates at Emerging Infections Program Sites - United States, 2019-2020.

Nontuberculous mycobacteria (NTM) cause pulmonary and extrapulmonary infections. Although isolation of NTM from clinical specimens has increased nationally, few studies delineated the molecular characteristics of extrapulmonary NTM. Extrapulmonary isolates were collected by four Emerging Infections Program sites from October 2019 to March 2020 and underwent laboratory characterization, including matrix-assisted laser desorption ionization-time of flight mass spectrometry, Sanger DNA sequencing, and whole genome sequencing. Bioinformatics analyses were employed to identify species, sequence types (STs), antimicrobial resistance (AR), and virulence genes; isolates were further characterized by phylogenetic analyses. Among 45 isolates, the predominant species were Mycobacterium avium (n=20, 44%), Mycobacterium chelonae (n=7, 16%), and Mycobacterium fortuitum (n=6, 13%). The collection represented 31 STs across 10 species; the most common ST was ST11 (M. avium, n=7). Mycobacterium fortuitum and Mycobacterium abscessus isolates harbored multiple genes conferring resistance to aminoglycosides, beta-lactams, and macrolides. No known AR mutations were detected in rpoB, 16S, or 23S rRNAs. Slow-growing NTM species harbored multiple virulence genes including type-VII secretion components, adhesion factors, and phospholipase C. Continued active laboratory- and population-based surveillance will further inform the prevalence of NTM species and STs, monitor emerging clones, and allow AR characterization.

Distribution of nontuberculous mycobacteria in dental unit waterlines: A potential health hazard in the dental office

BackgroundIt is essential to control the microbiology of dental unit water lines (DUWs) to prevent the spread of nontuberculous mycobacteria (NTM) and associated oral diseases. Therefore, the objective of this study was to quantify the presence of NTM in the water of 112 DUWs from dental centers and 57 DUWs from individual dental offices in Tehran, Iran. MethodsA total of 169 water samples were collected from DUWs. After filtration through a 0.45 μm membrane, the samples were decontaminated with 0.005 % cetylpyridinium chloride and then cultured on two Lowenstein-Jensen media, incubated at 25 °C and 37 °C for 8 weeks. Positive cultures for mycobacteria were analyzed using phenotypic tests, and the NTM species were identified through 16S rDNA, rpoB, and hsp65 genes analysis. Drug resistance was also assessed. ResultsOf the total isolates, 38 (34.5 %) were classified as slow-growing mycobacteria (SGM), while 72 (65.5 %) were categorized as rapid-growing mycobacteria (RGM). NTM isolates were identified using molecular tests, including M. chelonae, M. abscessus, M. lentiflavum, M. mucogenicum, M. fortuitum, M. kansasii, M. simiae, M. gordonae, M. conceptionense, M. phocaicum, M. porcinum, and M. aurum. The NTM counts ranged from 50 to >500 CFU/500 mL across these 188 samples, with a median of 350 CFU/500 mL. Additionally, we reported two cases of intraoral infection caused by M. abscessus and M. chelonae, where the source of infection was traced to NTM-contaminated DUWs. ConclusionsThe study found that most DUWs contained water contaminated with NTM, posing a potential health risk to humans. This research underscores the necessity of stringent quality control and certification of DUW water, with particular emphasis on ensuring the absence of NTM.

Evaluation of the GenoType NTM-DR line probe assay for nontuberculous mycobacteria using whole genome sequences as reference standard

Pulmonary nontuberculous mycobacteria (NTM) disease is an emerging public health challenge that is especially problematic in people with cystic fibrosis (CF). Effective treatment depends on accurate species and subspecies identification and antimicrobial susceptibility status. We evaluated the GenoType NTM-DR VER 1.0 assay using biobanked NTM isolates with whole genome sequence (WGS) data and control isolates (total n=285). Species and subspecies detection sensitivity and specificity were 100 % for all species and subspecies except for two subspecies of M. intracellulare, that demonstrated a small degree of discrepant identification between M. intracellulare subspecies intracellulare and subspecies chimaera. All antimicrobial resistance markers were identified with 100 % sensitivity and specificity.We conclude that the GenoType NTM-DR assay offers a rapid and accurate option for identifying the most frequently encountered pathogenic NTM taxa and drug resistance markers.SUPPORT: Colorado CF Research Development Program and Colorado CF National Resource Centers funded by the Cystic Fibrosis Foundation, NJH Advanced Diagnostics Laboratories, Colorado Advanced Industries Accelerator Grant

Increasing trends of non-tuberculous mycobacteria clinical isolates in Guangzhou, China

Non-tuberculous mycobacteria (NTM) are one of major public health concern. The current study aimed to find the prevalence trends of NTM in Guangzhou, China from January 2018 to December 2023. A total of 26,716 positive mycobacterial cultures were collected. Thirty-six specimens with incomplete personal information were excluded. The remaining 26,680 specimens were identified using a gene chip method. 16,709 isolates were Mycobacterium tuberculosis (MTB) (62.63 %), and 9,971 were NTM (37.37 %). 43.43 % (4,330/9,971) of NTM isolates were male, and 56.57 % (5,641/9,971) were female (χ2 = 24.36, P < 0.05), a male to female ratio of approximately 1:1.30. Infections in individuals with aged 40 years and above was higher (77.63 %) than below 40 years (22.37 %) (χ2 = 4.94, P = 0.026). The annual NTM isolation rates from 2018 to 2023 were 32.03 %, 34.00 %, 36.27 %, 38.58 %, 38.99 %, and 43.24 %, respectively, showing an increasing trend (χ2 for trend = 0.097, P < 0.05) (R = 0.097, P < 0.05). Out of 9,971 NTM isolates, 8,881 cases include only five common NTM species (MAC, M. abscessus/M. chelonae, M. kansasii, M. fortuitum, and M. gordonae). The overall NTM isolation rate was 37.37 %. The NTM isolation rate was significantly higher than the national average, showing an increasing trend over the last six years.

Analysis of Clinical Isolation Characteristics of Nontuberculous Mycobacteria and Drug Sensitivity of Rapidly Growing Mycobacteria in the General Hospital of Guangzhou, China.

The clinical distribution characteristics of nontuberculous mycobacteria (NTM) in general hospital were explored to guide the clinical diagnosis and treatment of NTM infection. Samples with positive mycobacterium culture in the First Affiliated Hospital of Guangzhou Medical University were collected and identified through PCR. Phenotypic drug sensitivity experiments were conducted on 44 Mycobacteroides abscessus isolated from clinical departments with broth microdilution method, and rrl, rrs and erm (41) genes associated with drug resistance were detected. From September 2020 to July 2023, 314 mycobacterium-positive isolates were separated from patients in the First Affiliated Hospital of Guangzhou Medical University, with 147 (46.8%) NTM isolates were included in our study. The samples were respiratory tract specimens mainly, with 64% bronchoalveolar lavage fluid. Of 144 cases identified, samples were from 133 patients (60 males and 73 females; gender ratio of 0.82:1). NTM was mainly isolated from the people aged 40 and above, especially females (χ2 = 10.688, P = 0.014). M. abscessus (61, 42.36%), M. intracellulare (35, 24.31%) were the two most NTMs in this hospital. Clinical strains of M. abscessus exhibited high resistance to antibiotics, except for cefoxitin (31.8%), linezolid (25.0%), amikacin (0%), and clarithromycin (18.2%). Among 8 strains of M. abscessus with clarithromycin acquired resistance, just 4 strains (50.0%) showed mutations (A2270G, A2271G) in rrl gene, but a new mutation (C2750T) was detected in 1 strain. Among 14 strains of M. abscessus with clarithromycin-induced resistance, 13 (93.0%) strains had T28 erm (41) gene and 1 (7.0%) strain had C28 erm (41) gene. M. avium-intracellulare complex was gradually becoming predominant strain in Guangzhou area. The resistant situation of M. abscessus in general hospital had shown severe. Potential mutation in rrl gene associated with clarithromycin acquired resistance of M. abscessus were found, but drug-resistant mechanism remained unclear.

Isolation and identification of non-tuberculous mycobacteria from aquarium fish in Ilam, Iran

Non-tuberculous mycobacteria (NTM) are among the most important pathogens in wild, captive, marine, and freshwater fish species. So, it is important to consider fish as the primary source of infection for aquarium fish and humans. The present study analyzed the occurrence of NTM in aquarium fish in Ilam, west of Iran. In total, 50 samples of infected fish were collected from different aquariums. Following initial sample processing, sediment of each sample was inoculated into Lowenstein-Jensen and Herrold egg media. The positive colonies were investigated with, growth rate, pigmentation, colony morphology, niacin accumulation, nitrate reduction, catalase activity, urease activity, and arylsulfatase activity. Also, molecular identification was carried out by sequencing of heat shock protein 65 kD gene (hsp65) sequence analysis. According to our results, NTM were isolated from 13 samples (26%), comprising 6 (46.2%) rapid growing, and 7 (53.8%) slow growing mycobacteria. In addition, Mycobacterium marinum was the most common NTM isolated in ornamental fish, which is potentially dangerous for both fish and humans. In conclusion, the current study indicates that ornamental fish play a significant role as a source of NTM.

The Drug Susceptibility of Non-Tuberculous Mycobacteria (NTM) in a Referral Hospital in Rome from 2018 to 2023.

Background: The treatment of non-tuberculous mycobacterial (NTM) infections is challenging because of the difficulty in obtaining phenotypic (pDST) and/or molecular (mDST) drug susceptibility testing and the need of a multi-drug regimen. Objectives: The objective was to describe the in vitro susceptibility patterns of various NTM species through an analysis of susceptibility results obtained on isolates collected between 2018 and 2023. Methods: Species identification and mutations in rrs or rrl genes (mDST) were identified by a line probe assay, while the pDST was performed by broth microdilution and interpreted according to CLSI criteria. Results: We analysed 337 isolates of NTM belonging to 15 species/subspecies. The Mycobacterium avium complex (MAC) was the most common (62%); other species identified included M. gordonae (11%), M. kansasii (5%), the M. abscessus complex (8%), M. chelonae (6%), and M. fortuitum (2%). The results of pDST (claritromycin and amikacin) and mDST (rrl and rrs genes) on 66 NTM strains showed that while wild-type rrl and rrs occurred in 86.3% and 94% strains, respectively, the pDST showed 88% sensitivity for clarithromycin and 57.5% for amikacin. The main incongruity was observed for macrolides. Conclusions: Most NTM are likely to be susceptible to macrolides and aminoglycosides. The molecular identification of resistant genotypes is accurate and strongly recommended for optimal patient management.

Nontuberculous Mycobacteria Isolates in Respiratory Samples and Mycobacterial Pulmonary Disease in an Area of Northern Spain

IntroductionThe epidemiology of nontuberculous mycobacteria (NTM) is not well known. In this study, we aimed to determine the incidence of NTM isolates and nontuberculous mycobacterial pulmonary disease (NTM-PD) in five closely located hospitals in an area of northern Spain and analyse differences between them. Material and methodsDemographic, microbiological, clinical and radiological data were collected retrospectively from all patients with a NTM isolated from respiratory specimens at five hospitals between 2012 and 2019. Mycobacterium gordonae isolates were excluded. Once the data was collected, it was determined which patients met the NMT-PD criteria. Results594 patients were included in the study. The mean incidence rate of NTM isolates across all five hospitals in the period studied was 4.15 per 100,000 person-year, while the rate of NTM-PD was 1.2. The annual number of isolates showed an upward trend over this period, but the same did not occur in the number of cases of NTM-PD. The species most frequently isolated were Mycobacterium avium complex (MAC) and Mycobacterium xenopi and those most frequently causing disease were MAC and Mycobacterium kansassi. There were significant differences between the five centres. ConclusionsOur results are in line with similar studies in Europe in terms of NTM isolation and NTM-PD incidence and species isolated; however, we do not see the upward trend in NTM-PD rates described elsewhere. The great variability in isolation and disease rates, as well as in species isolated in geographically close areas, underlines, in our opinion, the importance of local environmental factors.

Non-tuberculous mycobacterium isolations from tuberculosis presumptive cases at the National Tuberculosis Reference Laboratory Kenya, 2018–2019

Background: Mycobacterial pathogens are among the top causes of diseases in humans. In Kenya, incidences of Non-Tuberculous Mycobacteria (NTM) species have steadily been on the increase. Most NTMare resistant to first line treatment of tuberculosis and have a challenge in timely and accurate diagnosis. Misdiagnosis has led to prescribing anti-tuberculosis regimens to patients suffering from NTM. We aimed to determine the most prevalent Non-Tuberculous Mycobacterium in Kenya. Methods: We reviewed records from the National Tuberculosis Reference Laboratory(NTRL ) Laboratory information management system (LIMS) between January 2018 and December 2019 for the patients on surveillance. All isolates were cultured in Mycobacterial Growth Indicator Tubes (MGIT) and incubated for detection using BACTEC™ MGIT™ system. Those with negative acid-fast bacilli (AFB) growth and negative for Mycobacterium Tuberculosis Complex Species (MTBC) protein-MPT64 were suggestive of NTM infections, which were sub-cultured in MGIT and characterized using Line Probe Assay (LPA) GenoType® MTBDR CM/AS. Descriptive and bivariate analysis was done. Results: Of the total 24,549 records reviewed, 167(0.7%) were NTM isolates. Males comprised of 74.2% (124/167), and the mean age was 42 years (SD±16), age group 35-44 years had the highest NTM at 26.3% (44/167). Nairobi had 12.6% (21/167), Mombasa 10.8% (18/167), Kilifi and Meru each had 7.8% (13/167). Eleven isolated species comprised of Mycobacterium intracellulare 35.3% (65/167), M. fortuitum at 27% (48/167), and M. scrofulaceum at 10.2% (17/167). Previously treated patients had higher NTM [63.5% (106/167)] than Drug-resistant follow-up patients [26.9% (45/167)]. Coinfection with HIV was at 27.5% (46/167). Conclusion: Previously treated patients should have an additional screening of NTMS, and drug susceptibility testing should be done before initiation of treatment.

Prevalence and predictors of NTM in presumed/confirmed drug-resistant TB.

Non-tuberculous mycobacteria (NTM) are increasingly isolated in individuals with presumed/confirmed pulmonary TB. We aimed to estimate the prevalence and species distribution of NTM among presumed/confirmed drug-resistant TB (DR-TB) individuals and determine NTM isolation predictors. Sputum samples collected for DR-TB diagnosis and follow-up from 2012 to 2021 in Ghana were retrospectively analysed. Samples were subjected to sputum smear microscopy (SSM) and mycobacterial culture. The MPT64 assay was performed on positive cultures to distinguish between Mycobacterium tuberculosis complex MTBc and NTM. NTM isolates were re-cultured for species identification using GenoType® Mycobacterium CM/AS line-probe assay, polymerase chain reaction, and Sanger sequencing targeting 16S rRNA and rpoB genes. MTBc isolates identified by GenoType underwent spoligotyping. A logistic regression model was used to identify the predictors of NTM isolation. Of the 2,492 samples, 839 (33.7%) tested culture-positive for mycobacteria, with 257 (30.6%) presumed to be NTM. Of these, 53 (23.6%) were identified at the species level, with a predominance of M. intracellulare (66.0%). MPT64 testing missed 18 (3%) MTBc isolates. Logistic regression showed increased odds of NTM isolation in follow-up samples (aOR 2.41, 95% CI 1.46-3.99). NTM species were isolated from 46 patients, with four classified as NTM pulmonary disease. Enhancing our understanding of local NTM epidemiology and improving local diagnostic capabilities can optimise patient management strategies and outcomes.

Identification of Nontuberculous Mycobacterium Species by Polymerase Chain Reaction - Restriction Enzyme Analysis (PCR-REA) of rpoB gene in Clinical Isolates.

Nontuberculous mycobacteria (NTM) infections are an emerging global health concern with increasing incidence. Conventional identification methods for NTM species in clinical settings are prone to errors. This study evaluates a newer method, polymerase chain reaction-restriction enzyme analysis (PCR-REA) of the rpoB gene, for NTM species identification. The study identified NTM species in clinical samples using conventional biochemical techniques and compared the results with PCR-REA of the rpoB gene. This cross-sectional study was conducted at a tertiary health-care center in North India over 18 months, analyzing both pulmonary and extrapulmonary samples. Two hundred and forty-seven NTM isolates were identified using phenotypic and biochemical methods. The same isolates were subjected to rpoB gene amplification by PCR followed by REA using Msp I and Hae III enzymes. Conventional methods identified 12 different NTM species (153 slow-growing and 94 rapid-growing), whereas PCR-REA identified 16 species (140 slow-growing, 107 rapid-growing). The Mycobacterium avium intracellulare complex was the most common species isolated. PCR-REA demonstrated higher resolution in species identification, particularly in differentiating within species complexes. PCR-REA of the rpoB gene proves to be a simple, rapid, and more discriminative tool for NTM species identification compared to conventional methods. This technique could significantly improve the diagnosis and management of emerging NTM infections in clinical settings.

Multi-year Epidemiology of Nontuberculous Mycobacteria Across a Diverse Healthcare System

Background: Nontuberculous mycobacteria (NTM) are ubiquitous potential pathogens implicated in healthcare-associated outbreaks. There is a paucity of studies describing transmission risk in the healthcare setting. To estimate the potential healthcare-associated transmission of NTM, we characterized the frequency of NTM clinical isolates across our multi-facility healthcare system. Method: We performed a retrospective review of all clinical NTM isolates at 21 healthcare facilities in a large health system between January 2019 through June 2023 (inclusion criteria: all first unique species). We analyzed the quarterly frequency of isolates for each species, by facility. We identified higher-than-expected species frequencies, which was defined as a quarterly frequency ≥50% higher than the average quarterly frequency for that facility, for the entire study period (analysis omitted for any hospital with an average quarterly frequency 10 unique patient isolates in any 12-month period or &gt;2 in a single month except for M. abscessus at Hospital A. The quarterly frequency of the three most common species among hospitals with ≥2 unique isolates per 12-month period are displayed in figure 2. An increase of 50% from the average quarterly infection count occurred 34 times for M. avium complex across 10 hospitals, 14 times for M. gordonae across 2 hospitals and 14 times for M. lentiflavum across 2 hospitals (Figure 3). Conclusion: A diverse group of NTM were isolated across our healthcare system over the study period, most commonly M. avium complex, M. gordonae, and M. lentiflavum, each with hospital-specific temporal frequencies that suggest the potential for undetected outbreaks, while frequencies of less commonly isolated species were rarely suggestive of potential undetected outbreaks. Further epidemiologic investigation of in-hospital transmission routes, with whole genome sequencing to determine genetic relatedness, is necessary to identify undetected outbreaks.

Nontuberculous mycobacterial infection in Wisconsin children and adolescents

BackgroundThe epidemiology of nontuberculous mycobacteria (NTM) infections in the pediatric population is not well described. We estimated the incidence of NTM infection in Wisconsin children and adolescents, and the frequency and type of infection caused by different NTM pathogens. Associations between NTM infection and race/ethnicity and social disadvantage, respectively, were also investigated. MethodsThis retrospective cohort study evaluated reports of NTM infection in Wisconsin residents under 18 years of age submitted to a state-wide database between 2011 and 2018. Demographics of the cohort, including a social disadvantage score (Area Deprivation Index (ADI)), are described. Specimen type and NTM species are enumerated for reported isolates. ResultsThere were 224 NTM isolates from 212 children and adolescents. Median age of participants was 3 years; 55 % were female. Cumulative incidence did not vary significantly between the larger racial groups or for the various ADI score groups. Compared to white participants (157), there was a significantly lower cumulative incidence of NTM infection in multiracial individuals (2). Mycobacterium avium complex (MAC) was the most frequently isolated organism (69 %). The majority of isolates (52 %) were from skin and soft tissue, which included lymph node specimens. Annual incidence did not vary significantly over the study period. ConclusionsThe epidemiology of pediatric NTM infections in this cohort is consistent with previous pediatric reports of higher rate of infection in females and predominance of skin and soft tissue infections. Disparities in disease burden across racial/ethnic and socio-economic groups were not demonstrated, but these factors should be further explored in larger pediatric studies of diverse U.S. populations.

Micobacterias no tuberculosas: cuando categorizarlas en pediatría

Background: The term "nontuberculous mycobacteria" refers to more than 170 different species of bacteria that are not Mycobacterium tuberculosis or M. leprae. These bacteria can cause a variety of infections in children. Accurate diagnosis is crucial, as they can be confused with other diseases. Treatment can be challenging due to antibiotic resistance in some strains. The literature review focuses on improving the diagnosis and treatment of these infections in the pediatric population. The characterization of these bacteria, through methods such as PCR, is essential for effective treatment. Material and methods: A systematic review was performed to determine the need to categorize nontuberculous mycobacteria in pediatrics. Various databases and Boolean operators were used to search for relevant information. Inclusion and exclusion criteria were applied to select documents. The review covered the period from 2012 to 2023. They focused on pediatric studies on nontuberculous mycobacteria. Results: The article "Idiopathic CD4+ lymphocytopenia and juvenile laryngeal papillomatosis" describes a case of juvenile laryngeal papillomatosis (JLP) that was complicated by idiopathic CD4 lymphocytopenia (ICL). Despite treatments and surgeries, JLP progressed. The patient developed ICL based on the decrease in CD4+ lymphocytes without HIV. After receiving interferon-alpha with partial response, he died. The study "Prevalence and species spectrum of both pulmonary and extrapulmonary nontuberculous mycobacteria isolates" highlights the high prevalence of nontuberculous mycobacteria in India, especially M. abscessus. "Nontuberculous Mycobacteria in Denmark" evaluates the incidence and clinical relevance of NTM in Denmark from 1991 to 2015, finding a stable incidence and differences in age groups and species. These studies enrich the understanding of these medical conditions. Conclusion: The four studies analyzed offer a global vision of the incidence and characteristics of nontuberculous mycobacteria (NTM) in various regions. Although they all address NTM, they reveal geographic variability in their incidence and characteristics. A global increase in the incidence of NTM is observed, raising concerns about its clinical relevance. Furthermore, the study in New York highlights the increase in NTM in densely populated urban environments. Botswana underlines the importance of accurate diagnosis, especially in areas with high prevalence of tuberculosis and HIV. In Denmark, no significant increase in the incidence of NTM is observed, suggesting regional variability. Together, these findings emphasize the need to understand the local epidemiology of NTM and the importance of its prevention and control

Attenuated tuberculin skin test responses associated with Mycobacterium intracellulare sputum colonization in an adolescent TB prevalence survey in Western Kenya

IntroductionExposure to Non-tuberculous Mycobacteria (NTM) varies regionally and may partly explain the disparate outcomes of BCG vaccination and tuberculosis (TB) susceptibility. MethodsWe examined NTM sputum colonization, associations with clinical characteristics, and tuberculin skin test (TST) responses in an adolescent TB prevalence survey. ResultsAmong 5004 adolescents screened, 2281 (45.5 %) were evaluated further. TB and NTM prevalence rates were 0.3 % and 8.0 %, respectively. Among 418 NTM isolates, 103 were unidentifiable, and 315 (75 %) comprised 15 species, the most frequent being M. intracellulare (MAC) (108, 26 %), M. scrofulaceum (96, 23 %) and M. fortuitum (51, 12 %). “NTM colonized” adolescents had less frequent chronic cough and night sweats (adjusted odds ratio [aOR] 0.62, 95 % confidence interval [CI] 0.44-0.87and aOR 0.61, CI 0.42–0.89 respectively), and lower TST induration (median 11 mm (interquartile range [IQR] 0–16) vs 13 mm (IQR 6–17; p = 0.006)) when compared to “NTM not colonized” participants. MAC, but not M. scrofulaceum or M. fortuitum, was associated with decreased TST induration (median 7.5 mm (IQR 0–15) vs 13 mm (IQR 6–17) among “MAC colonized” vs “not colonized”, p = 0.001). ConclusionWe observed high NTM prevalence rates with species-specific associations with TST induration, consistent with a model of species-dependent heterologous immunity among mycobacteria.