Evaluation of Antibiotic Resistance and Biofilm Production among Clinical Strain Isolated from Medical Devices

Abstract

Microbial biofilms pose a serious threat to patients requiring medical devices (MDs). Prolonged periods of implantation carry a high risk of device-related infections (DRIs). Patients with DRIs often have negative outcomes following the failure of antibiotic treatment. Resistant DRIs are mainly due to the MDs contamination by bacteria producing biofilm. The present study aimed to detect biofilm formation among MD bacterial isolates and to explore their antibiotic resistance profile. The study was conducted on 76 MDs, collected at University Hospital of Campania "Luigi Vanvitelli," between October 2019 and September 2020. Identification of isolates and antibiotic susceptibility testing were performed using Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) and Phoenix Becton Dickinson, respectively. Biofilm-forming abilities were assessed using the tissue culture plate (TCP) method. Among the 94 MDs isolated strains, 42.7% were Gram-positive, 40.3% Gram-negative, and 17% Candida species. Among 78 bacterial strains, 43.6% were non-biofilm producers while 56.4% produced biofilms. All biofilm producing isolates were sensitive to a limited spectrum of antibiotic classes. All moderate and strong biofilm producers and 81% of weak biofilm producers were Multidrug Resistance (MDR) strains. In contrast, among non-biofilm producers, only 11.8% were classified as MDR strains. Our results highlighted that Sulfamides and Glycopeptides for the major Gram-positive strains and Fluoroquinolones, Carbapenems, and Aminoglycosides for the most represented Gram-negative isolates could be the most suitable therapeutic choice for most biofilm-DRIs.

Figure 1

Prevalence of bacterial and yeast strains isolated from medical devices.

Figure 2

Monomicrobial (a), bimicrobial (b), and trimicrobial (c) contamination of the medical devices studied.

Figure 3

Distribution of MDR and NO-MDR bacterial strains isolated from medical devices (p value < 0.05).

Figure 4

Biofilm formation among MD isolates.

Figure 5

Biofilm formation analysis of MD isolates. (a) Biofilm production level of MDR, red bars, and NO-MDR, yellow bars. The green bars indicate negative and positive controls, also represented by SEM. Dashed line represents the cutoff value. (b) Prevalence of MDR and NO-MDR strains among the different biofilm productions. (c) Distribution of biofilm formation with indicated resistance phenotypes.

Figure 6

Susceptibility rate to different classes of antibiotics in E. coli (a), P. aeruginosa (b), K. pneumoniae (c), and CoNS (d) between biofilm and non-biofilm producers. ^∗p value< 0.05.