Clinical Characteristics and Antimicrobial Susceptibility of Mycobacterium intracellulare and Mycobacterium abscessus Pulmonary Diseases: A Retrospective Study

Diagnostic value of nanopore sequencing technology in nontuberculous mycobacterial pulmonary disease

OBJECTIVE

To explore the diagnostic value of nanopore sequencing technology for detecting nontuberculous mycobacterial pulmonary disease (NTM-PD) in bronchial alveolar lavage fluid (BALF).

METHODS

A retrospective analysis was conducted on 83 patients with suspected NTM-PD admitted to Anhui Chest Hospital from January 2021 to November 2023. All patients underwent bronchoscopic examination, and BALF samples were collected for smear acid-fast staining, mycobacterial culture, and nanopore sequencing. The diagnostic efficiencies of these three methods were compared.

RESULTS

Among these patients, 27 were diagnosed with NTM-PD, 43 with pulmonary tuberculosis (PTB), and 13 with other lung diseases (OLD). The sensitivity, specificity, positive and negative predictive value of nanopore sequencing for diagnosing NTM-PD were 88.9%, 87.5%, 77.4%, and 94.2%, respectively. Nanopore sequencing demonstrated significantly higher sensitivity than smear and culture methods. The area under the receiver operating characteristic (ROC) curve (AUC) for nanopore sequencing was 0.882, significantly higher than that of smear (0.547) and culture (0.658), with P values less than 0.05.

CONCLUSION

Nanopore sequencing technology has high diagnostic efficiency for NTM-PD and can directly identify bacterial species, but specificity issues should be considered in clinical application.

The epidemiology of pulmonary Mycobacterium abscessus species in Japanese population

BACKGROUND

Mycobacterium abscessus species (MABS) is now a most virulent rapidly growing mycobacteria (RGM), and the rapid increase of MABS was recently observed worldwide, including in Japan. Thus, we gathered evidences of the presence of pulmonary MABS in Japanese population from Japanese articles.

METHODS

we searched studies that addressed the isolation of pulmonary non-tuberculous Mycobacteria (NTM) or MABS from clinical respiratory specimens in Japan.

RESULTS

the ratio of MABS to NTM was 3.04% (95% confidence interval [CI]: 2.51-3.68), found using the meta-analysis of single proportions. The estimated mean age of patients infected with MABS was 67.72 years (95% CI: 65.41-70.02), found using the meta-analysis of single means. The estimated proportion of females, never smoker, and the co-infection with Mycobacterium avium complex (MAC) was 66.75% (95% CI: 59.23-73.50), 67.57% (95% CI: 62.43-72.32), and 36.74% (95% CI: 25.30-49.90), respectively. The characteristics of MABS in Japan were considerably different from that in Europe and United States from the perspective of age, gender, and complications, wherein the patients in these countries tended to be younger, had lower number of females, and had more occurrences of hereditary diseases, including cystic fibrosis (CF).

CONCLUSION

we hypothesized that the characteristics of MABS in the Japanese were involved in those of non-CF MABS, and the distribution of gender and age of MABS were similar to that of MAC in the Japanese.

Species identification and drug susceptibility testing of non-tuberculous mycobacteria by Line Probe Assay in Lambaréné, Gabon-a cross-sectional study

BACKGROUND

Non-tuberculous mycobacteria (NTM) are a group of bacteria that cause rare lung infections and are increasingly recognized as causative agents of opportunistic and device-associated infections in humans. In Gabon, there is a lack of data on NTM species identification and drug susceptibility. The aim of this study was to identify the frequency of NTM species and their genotypic susceptibility pattern to commonly used antibiotics for NTM infections in Gabon.

METHODS

A cross-sectional study was conducted at the CERMEL TB laboratory from January 2020 to December 2022, NTM subspecies identification and drug susceptibility testing to macrolides and aminoglycosides were performed using the genotype NTM-DR kit.

RESULTS

The study found that out of 524 culture-positive specimens, 146 (28%) were NTM, with the predominant group being Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABC). All MAC isolates were fully susceptible to macrolides and aminoglycosides, while five MABC isolates carried mutations indicative of reduced susceptibility to macrolide and aminoglycoside drugs.

CONCLUSIONS

These findings suggest that clinicians may use macrolides and aminoglycosides to manage NTM infections caused by MAC, but further investigation is required to determine MABC drug susceptibility.