Antibiotic resistance and genomic characterization of Mycobacterium abscessus complex isolates from patients with pulmonary tuberculosis in Iran: A multi-center study (2010-2021).

One hundred and eighteen sputum specimens suspected of Mycobacterium abscessus infection were collected. Species level identification of M. abscessus was performed by rpoB sequencing. Clonality analysis was done by multilocus sequence typing (MLST) for M. abscessus. Antibiotic susceptibility testing was performed for clarithromycin, amikacin, ciprofloxacin and moxifloxacin. Altogether 128 isolates were obtained and were subjected to rpoB gene sequencing for definite identification. Among them 59 were identified as M. abscessus, and these included 22 (37.28%) isolates of M. abscessus subsp. abscessus, 22 (37.28%) isolates of M. abscessus subsp. massiliense, and 15 (25.42%) isolates of M. abscessus subsp. bolletii. All 59 M. abscessus complex isolates were analyzed by MLST in this study. Certain sequence types (STs) were identified among the 59 isolates and were specific for each subspecies. Two STs (ST40 and ST33) were specific to M. abscessus subsp. abscessus, one ST (ST20) was specific to M. abscessus subsp. bolletii, and one ST (ST15) was specific to M. abscessus subsp. massiliense. In antibiotic resistance, clarithromycin susceptibility testing of 22 M. abscessus subsp. abscessus strains detected 15 (68.18%) resistant strains, while among 22 M. abscessus subsp. massiliense strains 5 (22.72%) exhibited resistance, and among 15 M. abscessus subsp. bolletii 8 (53.33%) were resistant. Our study revealed a significant level of antibiotic resistance in isolates of the M. abscessus complex.

Investigating The Antimicrobial Activity Of Different Root Canal Filling Pastes In Deciduous Teeth.

BACKGROUND: The antiseptic property of root canal filling materials is very important for the removal of residual pathogens from root canals. The aim of the current study was to investigate the antimicrobial activity of mineral trioxide aggregate (MTA), calcium hydroxide (CH), Metapex, zinc oxide eugenol (ZOE), and CEM-cement. MATERIALS AND METHODS: Four standard bacterial strains including Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (ATCC 27853), and Bacillus subtilis (ATCC 6633) and Candida albicans (ATCC 10231) were used. On five plates containing Brain Heart Infusion (BHI) agar, five cavities were made. Then, the plates were cultured by 0.1 mL of bacterial suspension with a concentration of 0.5 McFarland. Afterwards, the cavities were filled with the tested materials and were incubated at 37 °C for 24, 48, and 72 hrs. Diameters of microbial inhibition zones were then measured. RESULTS: The highest mean diameter of growth inhibition zones was observed around ZOE and then CH and CEM-cement. According to the Kruskal-Wallis test, there was a significant difference among the tested groups (P<0.041). CONCLUSION: Considering antimicrobial activity, CH was an acceptable alternative to ZOE.

Report of two cases of Mycobacterium europaeum from Iran.

Herein, we report repeated isolation of Mycobacterium europaeum from the sputum samples of an Iranian human immunodeficiency virus-infected patient and a cystic fibrosis patient with chronic pulmonary disease. To our knowledge, this is the first isolation of M. europaeum from human clinical specimens in Asia to be reported.