Research Article Open Access

Exposure to Biocides Leads to Ampicillin Resistance in Clinically Isolated Enterococcus faecalis: A Preliminary Study

Abstract

Background: Antibiotic resistance is one of the most urgent threats to the public health globally. The extensive use of biocides in clinical settings poses risk for emergence and spread of antibiotic resistance among nosocomial pathogens. This study aimed to investigate the effect of biocides exposure on the antibiotic susceptibility patterns, morphology and ultrastructure of clinically isolated Enterococcus faecalis.

Methods: The antibiotic susceptibility patterns of Enterococcus faecalis following biocides exposure were studied using disk diffusion and broth microdilution methods. Polymerase Chain Reaction (PCR) amplification was performed to confirm the ampicillin resistance genes. The effect on the morphological and ultrastructural of Enterococcus faecalis was characterized using transmission and scanning electron microscopy. All descriptive data from this study were presented as percentages.

Results: Exposure to subinhibitory concentration of hydrogen peroxide increased the MIC of Enterococcus faecalis EF2 and developed resistance to ampicillin. However, the exposure did not exhibit any effects to the ultrastructure and morphology of Enterococcus faecalis. Molecular analysis of Enterococcus faecalis EF2 and ampicillin resistant EF2 which was referred as EF2r in this study showed that both isolates contained pbp4 gene. Sequence analysis revealed that there was no mutation detected within the pbp4 gene thus suggesting that ampicillin resistance observed following exposure to subinhibition concentration of biocides did not cause any mutation within the pbp4 gene of Enterococcus faecalis EF2r.

Conclusion: This study demonstrated that exposure to subinhibitory concentration of biocides leads to reduced antibiotic susceptibility of the clinical Enterococcus faecalis. This investigation provides an insight into the event that could lead to the development and possible dissemination of antibiotic resistance determinants among nosocomial pathogens.

Amirah Fatihah Md Nordin, Nur Ainaa Nabihah Mohd Ghazali, Rosni Ibrahim, Siti Khadijah Adam, Azmiza Syawani Jasni*

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