Drug resistance and pathogenic spectrum of patients coinfected with nontuberculous mycobacteria and human-immunodeficiency virus in Chengdu, China

Epidemiology of Nontuberculous Mycobacteria in Tuberculosis suspects, Southwest of China, 2017-2022

Objectives

This study summarizes the epidemiological characteristics, species distribution, and drug sensitivity of clinical nontuberculous mycobacteria (NTM) isolates at the Public Health Clinical Center of Chengdu, China, from January 2017 to December 2022.

Methods

We retrospectively analyzed data from patients with clinically isolated NTM strains. Chi-square analysis assessed the rate of Mycobacterium strain isolation over 6 years.

Results

The number of samples tested for Mycobacterium tuberculosis (MTB) and/or NTM increased each year, while MTB detection decreased and NTM detection rose significantly each year (P=0.03). The average age of NTM patients was 51 ± 17.53 years, with a 14.1% HIV infection rate. The predominant isolates were Mycobacterium avium-intracellulare (MAC) and M. chelonae/M. abscessus, with 96.4% of cases being of Han ethnicity. Amikacin, moxifloxacin, and clarithromycin were effective against M. avium and M. intracellulare; linezolid, amikacin, and cefoxitin were effective against M. chelonae/M. abscessus. Over 90% of NTM cases originated from the respiratory tract.

Conclusion

The NTM isolation rate in Southwest China has risen in recent years, primarily among elderly patients with a high HIV co-infection rate. The main NTM isolates were MAC and M. chelonae/M. abscessus. Amikacin, moxifloxacin, clarithromycin, and linezolid exhibited strong antibacterial activity against SGM, while amikacin and linezolid displayed relatively better antibacterial activity against RGM. The prevalence of NTM infection may be positively associated with regional economic development and health conditions.

Treatment of non-tuberculosis mycobacteria skin infections

Non-tuberculosis mycobacteria (NTM) skin infections have become increasingly prevalent in recent years, presenting a unique challenge in clinical management. This review explored the complexities of NTM infections localized to the superficial tissues and provided valuable insights into the optimal therapeutic strategies. The antibiotic selection should base on NTM species and their susceptibility profiles. It is recommended to adopt a comprehensive approach that considers the unique characteristics of superficial tissues to improve treatment effectiveness and reduce the incidence of adverse reactions, infection recurrence, and treatment failure. Infection control measures, patient education, and close monitoring should complement the treatment strategies to achieve favorable outcomes in managing NTM skin infections. Further efforts are warranted to elucidate factors and mechanisms contributing to treatment resistance and relapse. Future research should focus on exploring novel treatment options, innovative drug development/delivery platforms, and precise methodologies for determining therapeutic duration. Longitudinal studies are also needed to assess the long-term safety profiles of the integrated approaches.

What do the clinical features of positive nontuberculous mycobacteria isolates from patients with HIV/AIDS in China reveal? A systematic review and meta-analysis

Background

China has a high burden of nontuberculous mycobacterial (NTM) infections. Immunocompromised populations, such as those with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), are at a higher risk of being infected with NTM than immunocompetent individuals. Yet, there is a paucity of information on the clinical features of positive NTM isolates from patients with HIV/AIDS in China. To address this gap, we conducted a systematic review and meta-analysis of existing studies, comparing them against current expert consensus to provide guidance for clinical practice.

Methods

Two researchers independently searched eight databases (SinoMed, China National Knowledge Infrastructure, Wanfang, VIP, Cochrane Library, PubMed, Embase, and Web of Science) from inception to 26 December 2022 to retrieve published Chinese- and English-language studies reporting clinical features of NTM-positive isolates among patients with HIV/AIDS in China.

Results

We included 28 studies with 1861 patients. The rate of positive NTM isolates detected from men among all patients was 87.3%. NTM species distribution was mainly Mycobacterium avium complex (64.3%), which was predominant in different regions. The five most common clinical symptoms were fever (68.5%), cough or expectoration (67.0%), appetite loss (49.4%), weight loss (45.5%), and superficial lymphadenectasis (41.1%). The prevalence of laboratory tests were as follows: albumin <35 g/L (55.6%), erythrocyte sedimentation rate >20 mm/h (91.4%), anaemia (59.0%), predominantly mild, CD4+ T cell count ≤50 pieces/μL (70.3%), and CD4+ T cell count 51-200 pieces/μL (22.1%). Lesion manifestations in thoracic imaging mainly included bilateral lung involvement (83.8%), showed stripe shadows (60.3%), patchy shadows (42.9%), nodules (40.6%), and bronchiectasis (38.6%). Accompanied signs included thoracic lymph node enlargement (49.5%). Seventy per cent of symptoms improved after treatment.

Conclusions

Focusing on clinical symptoms, laboratory tests, and thoracic imaging helps with initial screening for NTM infections. Physicians should raise awareness of the diagnosis and treatment of Mycobacterium avium complex, providing guidance for experimental treatment, screening of priority populations for NTM infections, and prophylactic treatment of NTM disease.

Registration

PROSPERO CRD42023388185.

Epidemiology of Nontuberculous Mycobacteria in Nanjing and MAB_0540 Mutations Associated with Clofazimine Resistance in Mycobacterium abscessus

Background

Nontuberculous mycobacteria (NTM) are easily misdiagnosed as multidrug-resistant tuberculosis (MDR-TB), and treatment drugs are very limited. The main objective of our study was to evaluate the minimal inhibitory concentration (MIC) in vitro of bedaquiline (BDQ), clofazimine (CFZ), linezolid (LZD), delamanid (DLM), and pretomanid (PA-824) for treatment of M. abscessus and M. intracellulare. Furthermore, we determined whether MAB_1448, MAB_4384, MAB_2299c, MAB_1483, MAB_0540, rplD, rplC, and rrl were related to drug resistance to provide an experimental basis for the use of these five drugs in the treatment of NTM.

Methods

We identified sample characteristics of epidemics in 550 patients with suspected NTM infection in Nanjing from 2019 to 2021 using the PCR-reverse spot hybrid method. Furthermore, we evaluated the MIC of BDQ, CFZ, DLM, LZD, and PA-824 against 155 clinical isolates of NTM using the microbroth dilution method. The resistant isolates were sequenced using Sanger sequencing.

Results

The top three dominant species of NTM distributed in Nanjing were M. intracellulare, M. avium, and M. abscessus. Notably, the proportion of M. abscessus infections increased. The proportion of M. abscessus increased from 12% in 2019 to 18% in 2021. Demographic analysis showed that female infection rates were substantialy greater than male for M. abscessus (P=0.017, <0.05). Our results demonstrate that NTM are highly sensitive to bedaquiline and clofazimine in vitro. However, delamanid and pretomanid had little effect on M. abscessus and M. intracellulare. In addition, we found 30-41 nucleotide deletion mutations and some novel point mutations in the MAB_0540 gene of M. abscessus that are resistant to clofazimine.

Conclusion

Bedaquiline, clofazimine, and linezolid were more successful in vitro treatments against M. abscessus and M. intracellulare. The MAB_0540 mutation may be associated with resistance of M. abscessus to clofazimine.

Distribution of nontuberculous mycobacteria in patients with and without HIV/AIDS in Chongqing

INTRODUCTION

In this study, the distribution of nontuberculous mycobacteria (NTM) strains in patients with and without HIV/AIDS in Chongqing, China was evaluated.

METHODS

A retrospective study was performed in January-December 2020 at Chongqing Public Health Medical Center. NTM strains were assessed by a multi locus phylogenetic analysis. The distribution of NTM strains in HIV/AIDS and non-HIV/AIDS groups was compared. CD4+ cell counts, imaging changes, and characteristics of mycobacterial species were determined.

RESULTS

In total, 324 patients with NTM infection (50 patients with HIV/AIDS and 274 patients without HIV/AIDS) were included. The most common etiological agent was M. abscessus (29%), followed by M. paraintracellulare (12%) and M. colombiense (11%). Predominant NTM species were M. avium (26%), M. colombiense (24%), and M. kansasii (18%) in patients with HIV/AIDS and were M. abscessus (32%), M. paraintracellulare (13%), M. fortuitum (10%), and M. intracellulare (10%) in patients without HIV/AIDS. For a CD4+ cell count of <200/μl, the predominant species were M. aviumin the HIV/AIDS group and M. abscessus in the non-HIV/AIDS group. With respect to radiologic characteristics, different NTM strains were associated with distinct imaging manifestations; for example, M. marseillense, M. kansasii, and M. parasenchytosis were more likely to induce cavities. Imaging cavities, bronchiectasis, and acinar-like changes were more common in the non-HIV/AIDS groups.

CONCLUSIONS

The infection rates of HIV and NTM in Chongqing are high, while M. abscessus, M. paraintracellulare, and M. colombiense are the main pathogens causing NTM diseases in Chongqing, and NTM strains differed significantly between patients with and without HIV/AIDS. Monitoring these indicators can help develop prevention strategies.

Clinical characteristic, Common sites and Drug resistance profile in Culture-confirmed EPTB/ HIV co-infection patients, Southwest of China

OBJECTIVES

There are few reports on EPTB/HIV co-infection patients, especially the drug resistance profile of culture-confirmed EPTB. The purpose of our study was to analysis the clinical characteristic, common sites and drug resistance profile of culture-confirmed EPTB/HIV co-infection patients in recent years in southwest of China.

METHODS

A total of 201 EPTB/HIV co-infection cases were selected for this study. Patient demographic and clinical characteristics were collected. Mycobacterium tuberculosis drug sensitivity testing was performed using the microporousplate ratio method.

RESULTS

For the 2884 culture-confirmed EPTB cases recruited, patients were predominantly male1921/2884(66.6%). Mean age was 31years. Two hundred and one cases were EPTB/ HIV co-infection patients(7.0 %), from 201 cases male make up 84.6% (170/201), mean age was 42 years (range 13-86/year). During the 7-years period, the mean number of EPTB/ HIV co-infection cases was 29 per year(range 12-49/year) at this institution. Diarrhea, headache and fever were the most common presenting symptom.DST results showed the resistance to any anti-tuberculosis drug was observed in 62(30.8%) patient isolates, while multidrug-resistant TB and extensively drug-resistant TB were found in 14(7.0%) and 10(5.0%) patients, respectively. The distribution of EPTB tissue type mainly in Meningeal and Lymph node, varies between different genders.

CONCLUSIONS

The immune level of EPTB/HIV co-infected patients was low and most were in advanced AIDS stage. Mainly young male, and the site of EPTB was mainly in the Meningeal and Lymph node. The most common symptoms were diarrhea, headache and fever and high rates of drug resistance were found.

16S and 23S rRNA Gene Mutation Independent Multidrug Resistance of Non-Tuberculous Mycobacteria Isolated from South Korean Soil

Non-tuberculous mycobacteria (NTM) are ubiquitous microorganisms that have the potential to cause disease in both humans and animals. Recently, NTM infections have rapidly increased in South Korea, especially in urbanized areas. However, the distribution of species and the antibiotic resistance profile of NTM in environmental sources have not yet been investigated. Therefore, we analyzed the distribution of species and the antibiotic resistance profile of NTM in soil within urban areas of South Korea. A total of 132 isolates of NTM were isolated from soil samples from 1 municipal animal shelter and 4 urban area parks. Among the 132 isolates, 105 isolates were identified as slowly growing mycobacteria (SGM) and 27 isolates as rapidly growing mycobacteria (RGM) based on the sequences of the rpoB and hsp65 genes. The antibiotic resistance patterns of NTM isolates differed from species to species. Additionally, a mutation in the rrs gene found in this study was not associated with aminoglycoside resistance. In conclusion, our results showed that NTM isolates from South Korean soil exhibit multidrug resistance to streptomycin, amikacin, azithromycin, ethambutol, isoniazid, and imipenem. These results suggest that NTM may pose a public threat.

Non-Tuberculous Mycobacterial Diseases in Children

Non-tuberculous mycobacteria (NTMs) are ubiquitous and opportunistic emerging bacteria with the potential to colonize and eventually infect either immunocompromised or immunocompetent individuals. In the last three decades, the prevalence of disease caused by NTMs has increased in several countries. The increased prevalence of NTM infection can be explained by an ageing population with rising comorbidities, HIV infection, the common use of immunosuppressive drugs, and improved diagnostic methods. The aim of this review is to demonstrate the clinical relevance of NTMs in children, describing their features and manifestations, diagnostic tools, and therapeutic approaches. We collected data from the literature about NTM infections in young patients over the past five years (2014–2019) using the keywords “non-tuberculous”, “mycobacteria”, “paediatric”, “NTM”, “cystic fibrosis”, and “children”. Recent literature points out that NTMs are ubiquitous, with several species including both those that are pathogens for humans and those that are not. This means that, if a mycobacterium is isolated from a patient’s specimen, we have to distinguish between a simple colonization and an NTM-related disease. The start of treatment depends on many factors that are necessary to consider, such as clinical and imaging features, patient comorbidity and immunocompetence, drug adverse effects, and compliance with a very long therapy that can last many months. Due to the increasing prevalence and clinical relevance of NTMs, guidelines for their optimal management, especially in the presence of chronic underlying disease, are urgently needed.