The Effect of Antibiotics on Planktonic Cells and Biofilm Formation Ability of Collected Arcobacter-like Strains and Strains Isolated within the Czech Republic

Abstract

The purpose of this study was to test the in vitro effects of ampicillin, ciprofloxacin, clindamycin, erythromycin, gentamicin, and tetracycline on planktonic cells of Arcobacter-like microorganisms and on their biofilm formation ability. The minimum inhibitory concentrations (MICs) were determined by the microdilution method. Further, biofilm formation ability in the presence of various concentrations of antibiotics was evaluated by a modified Christensen method. Most of the 60 strains exhibited high susceptibility to gentamicin (98.3%), ciprofloxacin (95.0%), and erythromycin (100.0%). High level of resistance was observed to clindamycin and tetracycline with MIC50 and MIC90 in range of 4–32 mg/L and 32–128 mg/L, respectively. Combined resistance to both clindamycin and tetracycline was found in 38.3% of tested strains. In general, higher biofilm formation was observed especially at lower concentrations of antibiotics (0.13–2 mg/L). However, a significant decrease in biofilm formation ability of Pseudarcobacter defluvii LMG 25694 was exhibited with ampicillin and clindamycin at concentrations above 32 or 8 mg/L, respectively. Biofilm formation represents a potential danger of infection and also a risk to human health, in particular due to antimicrobial-resistant strains and the ability to form a biofilm structure at a concentration that is approximately the MIC determined for planktonic cells.

Smoothie Drinks: Possible Source of Resistant and Biofilm-Forming Microorganisms

“…This virulence-enhancing property of some microorganisms can play a significant role in disease pathogenesis. Infections caused by biofilms are typically chronic in nature, as the bacteria in the biofilm structure are resistant to the immune system response and to many antimicrobials [ 20 , 48 ]. The ability to form a biofilm was monitored in 85 strains isolated from smoothie drink samples by using the Christensen method with microtiter plates.…”

“…There were 8 wells in each experiment, and the experiments were independently repeated 3 times. The level of biofilm formation was categorized, according to a previously described classification system [ 20 , 21 ], as non-adherent (OD ≤ OD C ) or biofilm-forming strains (OD > OD C ), where OD C ( cut-off OD) is defined as three standard deviations above the mean OD of the negative control (blank value).. The measured and calculated OD/OD C (0.111/0.120) values were the same for all measurements.…”

Effect of Atmospheric Conditions on Pathogenic Phenotypes of Arcobacter butzleri

“…Šilha et al, (2021) suggested that Arcobacter-like species tend to prefer microaerophilic environments but are capable of forming biofilms in both microaerobic and aerobic conditions [57]. However, other studies have shown that aerobic conditions could favour biofilm formation for most of the studied strains, showing that a strain-dependent response could be responsible for the variability of the results [50,[57][58][59][60][61].…”

In Vitro Activity of Water Extracts of Olive Oil against Planktonic Cells and Biofilm Formation of Arcobacter-like Species

“…The increased resistance of bacteria to antimicrobials is a matter of great concern worldwide; therefore, monitoring the antimicrobial resistance of microorganisms is especially important [ 24 ]. Previous studies confirm that many natural matrices and extracts have antimicrobial activity.…”

“…There were 8 wells in each experiment, and the experiments were independently repeated 3 times. The level of biofilm formation of the Arcobacter -like strains was categorized, according to a previously described classification system [ 24 ], as non-adherent (OD ≤ OD C ) or biofilm-forming strains (OD > OD C ), where OD C ( cut-off OD) is defined as three standard deviations above the mean OD of the negative control (blank value). The measured and calculated OD/OD C (0.111/0.120) values were the same for all measurements.…”