Does subinhibitory concentrations of clinically important antibiotic induce biofilm production of Enterococcus faecium strains?

Abstract

Biofilm structures are the most resistant form of active microorganisms against sanitation, disinfection, and sterilization processes. One of the specific properties of biofilm is the development of antibiotic resistance that can be up to 1,000-fold greater than planktonic cells. Enterococcus faecium is a human pathogen that causes nosocomial bacteremia and at the present time, it is well known that most of the chronic infections are biofilm-based. Recent evidence suggested that subinhibitory concentrations (sub-MICs) of antibiotics have an important role in the evolution of antibiotic resistance and induction on biofilm formation. Based on this information, we aimed to determine the effect of subinhibitory antibiotic concentrations on biofilm formation and the role of the antibiotic concentrations on the enterococcal surface protein gene (esp). To determine the impact of clinically important antibiotics on biofilm production, crystal violet assay was used. Then, the effect of sub-MICs of antibiotics on the expression of the esp gene was investigated by quantitative real-time PCR. Biofilm production assays show that MIC/2 of erythromycin (ERT; 512 μg/ml), MIC/32 of vancomycin (VAN; 16 μg/ml), MIC/64 of streptomycin (STR; 32 μg/ml), and MIC/128 of kanamycin (KAN; 4 μg/ml) values induce maximum biofilm production compared with the control. According to q-PCR results, sub-MIC values of ERT, VAN, and STR antibiotics were found to enhance esp gene expression. In addition, despite the increasing biofilm production after KAN treatment, the antibiotic was not effective on the esp expression.

Norfloxacin Sub-Inhibitory Concentration Affects Streptococcus suis Biofilm Formation and Virulence Gene Expression

“…Norfloxacin demonstrated a significant increase in the growth of biofilm at 1/4 MIC and resulted in did not increase biofilm formation isolated SS_9801, SS_1886 and SS_595 at 1/8 and 1/16 MIC compared to the untreated norfloxacin. Some studies have strongly shown that the sub-MIC antibiotic can promote biofilm formation (Yuksel et al, 2018;Sato et al, 2018;Rachid et al, 2000). Our research brings clear evidence that sub-MICs of norfloxacins enhance the ability of S. suis to form biofilms.…”

“…Antibiotics are still the most effective measures in controlling bacterial pathogens. However, antibiotics are usually used at sub-MIC (Minimum Inhibitory Concentration) doses to prevent infection (Yuksel et al, 2018). The concentration of antibiotics in feed are often lower than the MIC in the treatment of infections (Adamowicz et al, 2018;Yang et al, 2013).…”

Helyi érzéstelenítők antibakteriális hatása

“…További vizsgálatok szükségesek annak eldöntésére is, hogy a helyi érzéstelenítők szubinhibitoros koncentrációja az antibiotikumokhoz hasonlóan befolyásolja-e a kórokozók adherenciáját, ami az infekció kialakulásának meghatározó lépése [20,21].…”

Sub-Inhibitory Concentrations of Amoxicillin and Tylosin Affect the Biofilm Formation and Virulence of Streptococcus suis

“…The total amount of antibiotics mixed into pig medicated feed in 2017 is estimated to be 843 tons [ 9 ]. Although the total amount of antibiotics used on farms is significant, due to the low oral absorption rate, irregular medication, and illegal use of low-dose antibiotic growth promoters, antibiotics often exist in livestock and poultry at sub-inhibitory concentration levels [ 10 ], which leads to prolonged disease and treatment difficulties. Oral antibiotic powders (Amoxicillin, lincomycin, oxytetracycline, doxycycline, gentamicin, and Tylosin, etc.)…”