Comparison of Cell Sizes of Methicillin-Resistant Staphylococcus aureus with Presence and Absence of the MecA Gene

Abstract

Staphylococcus aureus is a pathogenic microorganism that causes a wide range of infectious diseases of humans and animals. Staphylococcus aureus produces a large number of toxins, in particular enterotoxins, which enter the body together with food and cause disorders in the gastrointestinal tract. Moreover, S. aureus has several mechanisms of antibiotic resistance, which greatly complicates prevention of bacteria spread as community-acquired and nosocomial infections. The aim of the work was to determine and compare the differences in size of methicillin-resistant strains of S. aureus with different resistance mechanisms by scanning electron microscopy (SEM). Methods. Disc diffusion method was used to establish the mechanism of antibiotic resistance of the obtained isolates. After description of antibiotic resistant and selection of S. aureus isolates with resistance to penicillin and oxicilin, an SEM of the strains and a further comparison of their morphological characteristics, in particular cell size, with the help of Djmaizer v.5.1.10 software was carried out. Results. 54 isolates of S. aureus, obtained from various environmental objects, dairy farms and food products, were tested. PCR revealed sequences of the mecA gene, which is responsible for bacteria resistance to beta-lactams. We determined the cells size of S. aureus isolates resistant to penicillin and oxycillin and performed a comparative analysis of their morphological characteristics using SEM. Conclusions. In the course of the study, it was found that S. aureus isolates with mecA gene (mecA+) have smaller cell size than S. aureus isolates without mecA gene (mecA-).