Association between Biofilm Formation and Antimicrobial Resistance in Carbapenem-Resistant <i>Pseudomonas Aeruginosa</i>.

Abstract

Recently, carbapenem resistance in <i>P. aeruginosa</i> is an increasingly important problem globally. Biofilm formation is a well-known pathogenic mechanism of <i>P. aeruginosa</i>, and the gene, <i>pslA</i>, plays an important role in its primary stages. We studied the association between biofilm formation and <i>pslA</i> in carbapenem-resistant <i>P. aeruginosa</i> isolates, along with antimicrobial resistance and the prevalence of metallo-β-lactamase (MBL) genes, based on the presence of <i>pslA</i> 82 carbapenem-resistant <i>P. aeruginosa</i> isolates were collected from a tertiary hospital in Daejeon, Korea, between March 2008 and June 2014. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents were determined using the agar dilution method. Biofilm formation was measured by microtiter plate assay. PCR and sequencing were used to identify <i>pslA</i> and the MBL gene. 76 (92.7%) carbapenem-resistant isolates were biofilm producers. These biofilm producers showed higher levels of amikacin, ceftazidime, and cefepime resistance than non-producers. <i>pslA</i> was detected in 71 (93.4%) biofilm-producing isolates and these results were statically significant (<i>p</i><0.01). 11 isolates carrying <i>pslA</i> and <i>bla</i>_IMP-6 were extremely resistant to all antimicrobials tested. In this study, biofilm formation was significantly associated with <i>pslA</i> Furthermore, the coexistence of <i>pslA</i> and the MBL gene in carbapenem-resistant isolates likely contributed to the increase in antimicrobial resistance.