Evaluation of mycobacteria infection prevalence and optimization of the identification process in North Sardinia, Italy

Abstract

Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacteria (NTM) are the most common pathogens of mycobacterial infection, and their prevalence varies around the world. This study aimed to estimate the prevalence of mycobacterial infection and drug resistance in North Sardinia, Italy and to optimize the process of mycobacteria identification. From January 2020 to April 2023, samples from 1,836 suspected individuals in North Sardinia were analyzed. Conventional methods (microscopy smear and culture) and molecular methods (polymerase chain reaction, DNA probe, and mass spectrum) were used in MTB and NTM identification. Among 1,836 suspected individuals, 89 were MTB-positive and 44 were NTM-positive. Bronchial aspiration and bronchoalveolar lavage performed well as substitute specimens for sputum in MTB detection. For drug resistance, 71.91% of MTB and 83.33% of NTM were resistant to at least one antibiotic. The average turn-around time of MTB, slowly growing mycobacteria, and rapidly growing mycobacteria was 7.12, 48.87, and 11.27 days, respectively. Overall, our results show that the prevalence of mycobacterial infection in North Sardinia is relatively optimistic. However, the high proportion of drug resistance detected in the isolates is alarming. The implementation of advanced techniques could help optimize the process of mycobacteria identification. IMPORTANCE Mycobacterial infection is a major threat to public health worldwide. Accurate identification of infected species and drug resistance detection are critical factors in treatment. We focused on shortening the turn-around time of identifying mycobacteria species and antibiotic resistance tests.

Case report: Difficult diagnosis of Mycobacterium tuberculosis infection in patients after allogeneic hematopoietic stem cell transplantation: two case reports and a literature review

“…Immunological methods are often unsuitable for HSCT patients undergoing immunosuppressive therapy. Targeted polymerase chain reaction (PCR) methods have been developed to adapt to the evolving nature of the disease, including its epidemiology and global resistance patterns ( 11 , 16 ). Notably, advanced diagnostic tools such as X-pert MTB/RIF and the highly sensitive but less popular Xpert MTB/RIF Ultra, recommended by the World Health Organization (WHO), were not accessible to the patients in this study.…”