The association between biofilm formation ability and antibiotic resistance phenotype in clinical isolates of gram-negative bacteria: a cross-sectional study

Backgrounds: Antimicrobial-resistant pathogens that form biofilms cause treatment failure, increased mortality, and morbidity. Gram-negative bacteria (GNB) infections have become an emerging issue in antimicrobial resistance. This study analyzes the association between GNB biofilm formation ability and the antibiotic resistance phenotype in GNB clinical isolates. Methods: From June to August 2022, this cross-sectional study was conducted at Dr. Soetomo General Academic Hospital. Isolates derived from clinical specimens, including blood, urine, and respiratory tract specimens, were identified for antibiotic resistance phenotypes along with a quantitative biofilm formation assay. The antibiotic resistance phenotype was studied in relation to the GNB isolates' ability for biofilm formation. Results: Of the 271 isolates studied, 95 (35.1%) were non-MDR, 143 (52.8%) were MDR, and 33 (12.2%) were XDR. On the biofilm formation assay, 34 (12.5%) were non-biofilm producers, 237 (87.5%) were biofilm producers, consisting of 101 (37.3%) weak, 131 (48.3%) moderate, and 5 (1.8%) strong biofilm producers. Biofilm formation and antibiotic resistance in Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii were not significantly associated (p > 0.05). However, Escherichia coli isolates resistant to the antibiotics amikacin, imipenem, meropenem, and amoxicillin-clavulanate were found to have a higher predisposition to form biofilms. Klebsiella pneumoniae isolates resistant to gentamycin were also positively associated with biofilm formation. Conclusions: Gram-negative bacteria's ability to form biofilms is not associated with their antibiotic resistance phenotype; therefore, routine biofilm monitoring is critical for enhancing the quality of treatment strategy for biofilm-associated infection.