In vitro Activities of Antibiotic Combinations Against Mature Biofilms of Ventilator-Associated Pneumonia Isolates

Abstract

Background: The authors aimed to determine the efficacy of frequently used antibiotics, alone or in combination, against biofilms of ventilator-associated pneumonia isolates. Materials & methods: The authors determined the MICs, minimum biofilm inhibitory concentrations and minimum biofilm eradication concentrations of meropenem, ciprofloxacin and colistin as well as their combinations against planktonic forms and biofilms of Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii clinical isolates. Results: Generally, the minimum biofilm inhibitory concentrations and minimum biofilm eradication concentrations of the antibiotics were 1000-fold higher than their MICs, and synergy was provided by different concentrations of meropenem-colistin and meropenem-ciprofloxacin combinations with checkerboard and time–kill curve methods. Conclusion: The combination of meropenem and ciprofloxacin seems to be a good candidate for the treatment of biofilm-associated infections; none of the concentrations obtained as a result of the synergy test were clinically significant.

Association of biofilm formation, antimicrobial resistance, clinical characteristics, and clinical outcomes among Acinetobacter baumannii isolates from patients with ventilator‐associated pneumonia

“…The association between biofilm and antibiotic resistance in nosocomial pathogens has been reported in previous studies 26–29 . Vatan et al demonstrated that antibiotic use within the last 3 months was one of the significant factors related to biofilm, which is a major concern due to its role in antimicrobial resistance.…”

“…For the relationship between the biofilm and mortality, a previous study demonstrated that while patients infected with biofilm‐producing isolates exhibited higher mortality rates compared to those infected with non‐biofilm‐producing isolates, the crude mortality among VAP patients infected by these types of isolates did not show statistically significant differences 26 . In our study, we found higher mortality in patients infected with non‐biofilm‐producing isolates than those infected with biofilm‐producing isolates, but the difference did not achieve significance.…”

“…17,24,25 The association between biofilm and antibiotic resistance in nosocomial pathogens has been reported in previous studies. [26][27][28][29] Vatan et al demonstrated that antibiotic use within the last 3 months was one of the significant factors related to biofilm, which is a major concern due to its role in antimicrobial resistance. Moreover, a significant positive correlation was seen between biofilm-producing bacteria, especially Gram-negative strains, and extensive drug resistance.…”