Biofilm formation in Acinetobacter baumannii: associated features and clinical implications

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Acinetobacter baumannii is a significant opportunistic pathogen.
• Biofilm formation is a key virulence factor in bacterial infections.
• Understanding biofilm dynamics is crucial for infection control.

Purpose of the Study:

• To investigate biofilm formation in a cohort of Acinetobacter baumannii isolates.
• To correlate biofilm formation with antimicrobial resistance patterns.
• To identify clinical factors associated with biofilm-forming and non-biofilm-forming strains.

Main Methods:

• A microtitre plate assay was used to assess biofilm formation.
• Ninety-two unrelated Acinetobacter baumannii strains from a multicentre cohort were analyzed.
• Multivariate analysis was employed to identify associated clinical factors.

Main Results:

• 63% (56/92) of isolates formed biofilm.
• Biofilm-forming isolates showed lower resistance to imipenem (25% vs. 47%) and ciprofloxacin (66% vs. 94%).
• Biofilm formers caused all catheter-related infections and shunt-related meningitis; non-biofilm formers were associated with ICU stay, ciprofloxacin resistance, and respiratory samples.

Conclusions:

• Biofilm formation is prevalent in Acinetobacter baumannii.
• Biofilm-forming strains are associated with specific clinical infections and prior aminoglycoside exposure.
• Reduced resistance to imipenem and ciprofloxacin in biofilm formers warrants further investigation.