Biofilm is a Major Virulence Determinant in Bacterial Colonization of Chronic Skin Ulcers Independently from the Multidrug Resistant Phenotype

Abstract

Bacterial biofilm is a major factor in delayed wound healing and high levels of biofilm production have been repeatedly described in multidrug resistant organisms (MDROs). Nevertheless, a quantitative correlation between biofilm production and the profile of antimicrobial drug resistance in delayed wound healing remains to be determined. Microbial identification, antibiotic susceptibility and biofilm production were assessed in 135 clinical isolates from 87 patients. Gram-negative bacteria were the most represented microorganisms (60.8%) with MDROs accounting for 31.8% of the total isolates. Assessment of biofilm production revealed that 80% of the strains were able to form biofilm. A comparable level of biofilm production was found with both MDRO and not-MDRO with no significant differences between groups. All the methicillin-resistant Staphylococcus aureus (MRSA) and 80% of Pseudomonas aeruginosa MDR strains were found as moderate/high biofilm producers. Conversely, less than 17% of Klebsiella pneumoniae extended-spectrum beta-lactamase (ESBL), Escherichia coli-ESBL and Acinetobacter baumannii were moderate/high biofilm producers. Notably, those strains classified as non-biofilm producers, were always associated with biofilm producer bacteria in polymicrobial colonization. This study shows that biofilm producers were present in all chronic skin ulcers, suggesting that biofilm represents a key virulence determinant in promoting bacterial persistence and chronicity of ulcerative lesions independently from the MDRO phenotype.

Biofilm Formation and Detection of Fluoroquinolone- and Carbapenem-Resistant Genes in Multidrug-ResistantAcinetobacter baumannii

“…However, many current studies have reported increasing resistance to imipenem and ciprofloxacin. Di-Domenico et al [10] found A. baumannii isolates from patients with colonized skin ulcers to have 75% resistance to imipenem, 75% resistance to trimethoprim-sulfamethoxazole, and 91% resistance to ciprofloxacin. Addi-Ali et al [12] showed 92% of A. baumannii clinical isolates to be resistant to ciprofloxacin and 68% to be resistant to imipenem.…”

“…Recent studies have reported the biofilmforming ability of A. baumannii strains to be related to major virulence factors, promoting bacterial persistence and chronicity in a specific manner, distinct from the MDR phenotypes. In addition, quorum sensing, which is a communication mechanism used by bacteria to recognize population density fluctuations and control gene expression [7], has been shown to be associated with biofilm formation by A. baumannni [8][9][10]. Among the different A. baumannii virulence factors, the most important is their ability to produce biofilms and their survival in hospital environments, which is related to their high degree of antibiotic resistance [11,12].…”

Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis

“…The range of antibiotics tested is listed in the additional files section (Additional file 1). Strains were classified as MRSA when presenting both oxacillin resistance (MIC ≥4 mg/ml) and positive agglutination test for Penicillin-Binding Protein (PBP2, Oxoid, Basingstoke, UK) [76].…”

Investigating possible association between multidrug resistance and isolate origin with some virulence factors ofEscherichia colistrains isolated from infant faeces and fresh green vegetables

“…However, in that study they could not detect a correlation between MDR or non-MDR Pseudomonas aeruginosa and the strength of attachment to stainless steel surfaces. In another study, Di Domenico et al (2017) observed that 80% of clinical isolates were able to form biofilm. For these strains, the level of biofilm production between MDR isolates and non-MDR isolates was comparable and no significant difference was detected.…”

“…In another study, Di Domenico et al . () observed that 80% of clinical isolates were able to form biofilm. For these strains, the level of biofilm production between MDR isolates and non‐MDR isolates was comparable and no significant difference was detected.…”