Treatment of pulmonary disease caused by Mycobacterium kansasii

Prevalence of antibiotic resistance in clinical isolates of Mycobacterium kansasii: a systematic review and meta-analysis

INTRODUCTION

The prevalence of diseases caused by non-tuberculous mycobacteria (NTM), including M. kansasii, is increasing, necessitating further information to guide prevention, control, and treatment strategies.

AREAS COVERED

A comprehensive analysis of articles published until February 2023 was conducted on PubMed, Web of Science, and Scopus databases to investigate antibiotic resistance in M. kansasii species. Stata software version 17 was employed for all analyses.

EXPERT OPINION

A total of 1647 articles were obtained through database search. After removing duplicates and unrelated studies, 17 cross-sectional studies that examined the breakpoints proposed by CLSI were included. The rates of resistance of M. kansasii to various antibiotics were as follows: clarithromycin (0%), rifampin (1%), amikacin (0%), ciprofloxacin (14%), linezolid (0%), moxifloxacin (0%), rifabutin (1%), doxycycline (96%), and SXT (49%). Our findings underscore the importance of managing and monitoring the use of these antibiotics, as well as the need for further studies to elucidate the exact mechanism of M. kansasii resistance to these antibiotics.

Repurposing β-Lactams for the Treatment of Mycobacterium kansasii Infections: An In Vitro Study

Mycobacterium kansasii (Mkn) causes tuberculosis-like lung infection in both immunocompetent and immunocompromised patients. Current standard therapy against Mkn infection is lengthy and difficult to adhere to. Although β-lactams are the most important class of antibiotics, representing 65% of the global antibiotic market, they have been traditionally dismissed for the treatment of mycobacterial infections, as they were considered inactive against mycobacteria. A renewed interest in β-lactams as antimycobacterial agents has shown their activity against several mycobacterial species, including M. tuberculosis, M. ulcerans or M. abscessus; however, information against Mkn is lacking. In this study, we determined the in vitro activity of several β-lactams against Mkn. A selection of 32 agents including all β-lactam chemical classes (penicillins, cephalosporins, carbapenems and monobactams) with three β-lactamase inhibitors (clavulanate, tazobactam and avibactam) were evaluated against 22 Mkn strains by MIC assays. Penicillins plus clavulanate and first- and third-generation cephalosporins were the most active β-lactams against Mkn. Combinatorial time-kill assays revealed favorable interactions of amoxicillin-clavulanate and cefadroxil with first-line Mkn treatment. Amoxicillin-clavulanate and cefadroxil are oral medications that are readily available, and well tolerated with an excellent safety and pharmacokinetic profile that could constitute a promising alternative option for Mkn therapy.

Beyond the approved: target sites and inhibitors of bacterial RNA polymerase from bacteria and fungi

Covering: 2016 to 2022RNA polymerase (RNAP) is the central enzyme in bacterial gene expression representing an attractive and validated target for antibiotics. Two well-known and clinically approved classes of natural product RNAP inhibitors are the rifamycins and the fidaxomycins. Rifampicin (Rif), a semi-synthetic derivative of rifamycin, plays a crucial role as a first line antibiotic in the treatment of tuberculosis and a broad range of bacterial infections. However, more and more pathogens such as Mycobacterium tuberculosis develop resistance, not only against Rif and other RNAP inhibitors. To overcome this problem, novel RNAP inhibitors exhibiting different target sites are urgently needed. This review includes recent developments published between 2016 and today. Particular focus is placed on novel findings concerning already known bacterial RNAP inhibitors, the characterization and development of new compounds isolated from bacteria and fungi, and providing brief insights into promising new synthetic compounds.