Petkova Tsvetelina, Rusenova Nikolina, Danova Svetla, Milanova Aneliya
Department of Pharmacology, Animal Physiology, Biochemistry and Chemistry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria.
Department of Veterinary Microbiology, Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria.
Antibiotics (Basel). 2023 Jul 14;12(7):1187. doi: 10.3390/antibiotics12071187.
Biofilm-forming bacteria are associated with difficult-to-cure bacterial infections in veterinary patients. According to previous studies, N-acetyl-L-cysteine (NAC) showed an inhibitory effect on biofilm formation when it was applied in combination with beta-lactam antibiotics and fluoroquinolones. The lack of information about the effect of NAC on doxycycline activity against biofilm-forming strains was the reason for conducting this study. () ATCC 25923, O74, () ATCC 25922 and () ATCC 27853 were used to evaluate the activity of doxycycline with and without addition of NAC on planktonic bacteria and on biofilm formation. The minimum inhibitory concentrations (MICs) of doxycycline were not affected by NAC for Gram-negative strains and were found to be two times higher for the strains of . The minimum biofilm inhibitory concentrations (MBICs) for Gram-negative bacteria (2 μg/mL for ATCC 25922 and 32 μg/mL for ATCC 27853), determined using a standard safranin colorimetric assay, were higher than the MICs (0.5 and 4 μg/mL, respectively). The data suggest that the combinations of doxycycline and NAC could stimulate the growth of planktonic cells of and biofilm-forming ATCC 25922. NAC did not affect the strong inhibitory effect of doxycycline on the biofilm formation by the strains of
形成生物膜的细菌与兽医患者中难以治愈的细菌感染有关。根据先前的研究，N-乙酰-L-半胱氨酸（NAC）与β-内酰胺类抗生素和氟喹诺酮类联合应用时，对生物膜形成具有抑制作用。缺乏关于NAC对强力霉素抗生物膜形成菌株活性影响的信息是开展本研究的原因。使用（）ATCC 25923、O74、（）ATCC 25922和（）ATCC 27853评估添加和不添加NAC时强力霉素对浮游细菌和生物膜形成的活性。对于革兰氏阴性菌株，NAC不影响强力霉素的最低抑菌浓度（MIC），且发现（）菌株的MIC高出两倍。使用标准番红比色法测定的革兰氏阴性菌的最低生物膜抑菌浓度（MBIC）（ATCC 25922为2μg/mL，ATCC 27853为32μg/mL）高于MIC（分别为0.5和4μg/mL）。数据表明，强力霉素与NAC的组合可刺激（）浮游细胞和形成生物膜的ATCC 25922生长。NAC不影响强力霉素对（）菌株生物膜形成的强烈抑制作用。
