In Vitro Antimycobacterial Activity of Human Lactoferrin-Derived Peptide, D-hLF 1-11, against Susceptible and Drug-Resistant Mycobacterium tuberculosis and Its Synergistic Effect with Rifampicin

Abstract

Tuberculosis is a highly contagious disease caused by the Mycobacterium tuberculosis complex (MTBC). Although TB is treatable, multidrug-resistant, extensively drug-resistant, and totally drug-resistant forms of M. tuberculosis have become a new life-threatening concern. New anti-TB drugs that are capable of curing these drug-resistant strains are urgently needed. The purpose of this study is to determine the antimycobacterial activity of D-enantiomer human lactoferricin 1-11 (D-hLF 1-11) against mycobacteria in vitro using a 3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide colorimetric assay, resazurin microplate assay, and microscopic observation drug susceptibility assay. Three previously described antimicrobial peptides, protegrin-1, AK 15-6, and melittin, with potent anti-TB activity, were included in this study. The findings suggest that D-hLF 1-11 can inhibit the growth of M. tuberculosis with a minimum inhibitory concentration of 100–200 µg/mL in susceptible, isoniazid (INH)-monoresistant, rifampicin (RF)-monoresistant, and MDR strains. The peptide can also inhibit some nontuberculous mycobacteria and other MTBC in similar concentrations. The antibiofilm activity of D-hLF 1-11 against the biofilm-forming M. abscessus was determined by crystal violet staining, and no significant difference is observed between the treated and untreated biofilm control. The checkerboard assay was subsequently carried out with M. tuberculosis H37Rv and the results indicate that D-hLF 1-11 displays an additive effect when combined with INH and a synergistic effect when combined with RF, with fractional inhibitory concentration indices of 0.730 and 0.312, respectively. The red blood cell hemolytic assay was initially applied for the toxicity determination of D-hLF 1-11, and negligible hemolysis (<1%) was observed, despite a concentration of up to 4 mg/mL being evaluated. Overall, D-hLF 1-11 has potential as a novel antimycobacterial agent for the future treatment of drug-sensitive and drug-resistant M. tuberculosis infections.

Synergistic Antimicrobial Action of Lactoferrin-Derived Peptides and Quorum Quenching Enzymes

“…Since it has recently been demonstrated that bacteria can develop resistance to AMPs and that their combined use allows to delay the evolution of pathogen resistance [ 8 , 9 ], the use of combined forms of lactoferrin-derived AMPs seems to be the most appropriate way to avoid the development of resistance. Such combinations can be based not only on AMPs or antibiotics [ 43 , 44 ], but also on enzymes that are active against different G(+) and G(−) bacteria [ 45 , 46 , 47 ]. In vitro studies of the combined use of various AMPs derived from human and bovine lactoferrin with traditional antibiotics revealed the presence of a synergistic effect between polypeptides and antibiotics; however, the obtained results were insufficient to produce therapeutic effects in vivo [ 48 ].…”

A laboratory perspective on Mycobacterium abscessus biofilm culture, characterization and drug activity testing

“…Colloidal silver, the dendritic amphiphile 3Cam19, the thiopeptide antibiotic NF1001 and the rifamycin derivate 5j reduced mycobacterial viability in established biofilms ( Falkinham et al, 2012 ; Paulowski et al, 2022 ; Feizi et al, 2023 ; Kaur et al, 2024 ). Finally, the antimicrobial peptide D-hLF-1–11, a derivate of lactoferrin, seemed to not affect M. abscessus biofilm biomass ( Intorasoot et al, 2022 ).…”

Antibacterial, Anti-Biofilm and Pro-Migratory Effects of Double Layered Hydrogels Packaged with Lactoferrin-DsiRNA-Silver Nanoparticles for Chronic Wound Therapy

“…Basically, LTF is an iron-chelating protein found in blood and bodily secretions, such as tears, sweat, and vaginal secretions [ 29 , 30 ]. In reference to its anti-biofilm property, LTF has been shown to have synergistic effects in combination with agents [ 31 ], such as AgNPs [ 27 ] and Xylitol [ 32 ], against biofilm-producing organisms. Since biofilm formers are also common pathogens associated with diabetic foot ulcers [ 22 ], combining AgNPs and LTF could potentially inhibit biofilm formation and eradicate bacteria that are living in diabetic wounds.…”