Mycobacterium Biofilms

Abstract

The genus Mycobacterium includes human pathogens (Mycobacterium tuberculosis and Mycobacterium leprae) and environmental organisms known as non-tuberculous mycobacteria (NTM) that, when associated with biomaterials and chronic disease, can cause human infections. A common pathogenic factor of mycobacteria is the formation of biofilms. Various molecules are involved in this process, including glycopeptidolipids, shorter-chain mycolic acids, and GroEL1 chaperone. Nutrients, ions, and carbon sources influence bacterial behavior and have a regulatory role in biofilm formation. The ultrastructure of mycobacterial biofilms can be studied by confocal laser scanning microscopy, a technique that reveals different phenotypic characteristics. Cording is associated with NTM pathogenicity, and is also considered an important property of M. tuberculosis strains. Mycobacterial biofilms are more resistant to environmental aggressions and disinfectants than the planktonic form. Biofilm-forming mycobacteria have been reported in many environmental studies, especially in water systems. NTM cause respiratory disease in patients with underlying diseases, such as old tuberculosis scars, bronchiectasis, and cystic fibrosis. Pathogens can be either slowly growing mycobacteria, such as Mycobacterium avium complex, or rapidly growing species, such as Mycobacterium abscessus. Another important biofilm-related group of infections are those associated with biomaterials, and in this setting the most frequently isolated organisms are rapidly growing mycobacteria. M. tuberculosis can develop a biofilm which plays a role in the process of casseous necrosis and cavity formation in lung tissue. M. tuberculosis also develops biofilms on clinical biomaterials. Biofilm development is an important factor for antimicrobial resistance, as it affords protection against antibiotics that are normally active against the same bacteria in the planktonic state. This antibiotic resistance of biofilm-forming microorganisms may result in treatment failure, and biofilms have to be physically eradicated to resolve the infection. New strategies with potential antibiofilm molecules that improve treatment efficacy have been developed. A novel antibiofilm approach focuses on Methylobacterium sp. An understanding of biofilm is essential for the appropriate management of patients with many NTM diseases, while the recent discovery of M. tuberculosis biofilms opens a new research field.

2018 international consensus meeting on musculoskeletal infection: Summary from the biofilm workgroup and consensus on biofilm related musculoskeletal infections

“…In vitro experiments find that M. tuberculosis can form biofilm on metal surfaces; albeit less than on Polymethylmethacrylate (PMMA), and less than is formed by Staphylococci spp . Based on in vivo studies and clinical case reports biofilms in TB infections may contribute to casseous necrosis . Although no data from clinical trials exist to address this question, the Workgroup felt that the published scientific data are strong enough to warrant consensus opinion on the clinical implications for management of implant‐related infections caused by M. tuberculosis .…”

Inside out: microbiota dynamics during host-plant adaptation of whiteflies

“…Several fast-growing Mycobacterium species have been described as plantassociated epi/endophytes [40], while others were reported as gut-associated bacteria of Lepidoptera and aphid species [23,53]. Mycobacterium are known to produce biofilms, allowing them to adhere to different surfaces, but also to overcome unfavorable abiotic and biotic environments [54]. These capabilities ensure both colonization and survival in the adverse conditions present in the insects' gut following acquisition from the plant/environment [6].…”

Resistance of Tick Gut Microbiome to Anti-Tick Vaccines, Pathogen Infection and Antimicrobial Peptides

“…We asked whether biofilm α ( Figure 1) was associated with an increase in the abundance of biofilm formers, while biofilms β1 and β2 ( Figure 1) were associated with a reduction in the number of biofilm formers. The bacterial genera with higher abundance in response to anti-tick immunity include the strong biofilm formers Mycobacterium [36], Tepidimonas [37], Rothia [38] and Leuconostoc [39], whereas A. phagocytophilum infection and antimicrobial peptide reduced the presence of the biofilm formers Gracilibacteria [40] and Enterococcus [3], respectively.…”