# Prevalence of Panton-Valentine leucocidin (pvl) and exfoliative toxin A (eta) gene within methicillin resistant and sensitive Staphylococcus aureus in an urban tertiary referral hospital: A molecular epidemiology pilot study

## TL;DR

This study found that certain harmful genes are more common in a type of bacteria that is easier to treat than a drug-resistant form.

## Contribution

The study reports the first molecular epidemiology data on pvl and eta gene prevalence in MRSA and MSSA in North Sumatera.

## Key findings

- pvl was more prevalent in MSSA (99.75%) than in MRSA (84.2%).
- eta was present in all MSSA isolates but absent in 18.4% of MRSA isolates.
- Both pvl and eta were significantly more expressed in MSSA strains.

## Abstract

Background:
Staphylococcus aureus is well known to cause a multitude of clinical manifestations, from mild to severe bloodstream infections that could lead to death. Infections are common, either in community-acquired or hospital-acquired settings, and treatment remains a challenge due to methicillin-resistant
Staphylococcus aureus (MRSA). The pathogenesis of
S. aureus is mediated by several cell-surface and secreted virulence factors. The virulence factors discussed in this study are Panton-Valentine leucocidin (pvl) and exfoliative toxin A (eta).

Our pilot study aimed to observe pvl and eta as virulence gene prevalence in a North Sumatera tertiary referral health center.

Methods: Our study was a descriptive-analytical observational study with a cross-sectional design in which we collected isolates over a single time period. The frequency of genes is reported as a percentage comparison between MRSA and methicillin-sensitive
S. aureus (MSSA). Qualitative gene prevalence analysis was carried out using the polymerase chain reaction (PCR).

Results: Our results showed that from 38 MRSA sample isolates, six samples were found to be pvl-negative, or 15.7% of the total samples. From 40 MSSA sample isolates, one sample was found to be pvl-negative MSSA, or 0.025%. Regarding eta, from 38 MRSA sample isolates, 18.4% of the total sample did not have eta, while from 40 MSSA sample isolates, all samples were found to be positive for eta. We found that both pvl and eta were significantly more likely to be expressed in the MSSA strain.

Conclusions: Our study shows that pvl and eta are more likely expressed in MSSA strains than in MRSA strains in Indonesia.