Correlation between Biofilm Formation, Presence of Esp and gelE Genes in Clinical Isolates of Enterococcus Faecium at Imam Hossein Hospital, Shahroud

Abstract

Introduction: Enterococcus faecium is an important hospital-acquired pathogen known for its ability to form biofilms, a feature that contributes to its virulence and resistance to antibiotic treatments. Understanding the underlying mechanisms of this ability in clinical isolates is crucial. This study investigates the phenotypic and molecular characteristics associated with biofilm production in Enterococcus faecium strains isolated from various clinical samples.

Methods: A total of 88 Enterococcus faecium isolates were collected from inpatients and outpatients at Imam Hossein Hospital in Shahroud during 2022-2023. The isolates were analyzed for morphology, colony characteristics, species identification, and biochemical tests. Phenotypic evaluation of biofilm production was performed using the Congo Red Agar (CRA) method and the Microtiter Plate (MTP) method. PCR was used to identify the species and detect the presence of the esp and gelE genes.

Results: In this study, 60 (68.1%) and 76 (86.3%) isolates were able to produce biofilms using the CRA and MTP methods, respectively. The majority of samples were obtained from urine (48.8%) and blood (18.1%) with 95.3% and 81.2% of the respective isolates producing biofilms. PCR results revealed that 30.6% of the isolates carried the esp gene, and 53.4% carried the gelE gene. All these isolates were capable of producing biofilms, with 7.9% of the esp-positive strains and 10.1% of the gelE-positive strains forming strong biofilms.

Conclusion: The results of our study showed that most of the clinical samples are biofilm producers, and the esp and gelE genes play an important role in biofilm formation in patients. This not only indicates the spread of contamination and the occurrence of serious diseases, but also highlights the increasing advancement of drug resistance patterns.