Molecular characterization of typing and subtyping of Staphylococcal cassette chromosome SCC types I to V in methicillin-resistant from clinical isolates from COVID-19 patients.

BACKGROUND AND OBJECTIVES

Methicillin resistance is acquired by the bacterium due to gene which codes for penicillin-binding protein (PBP2a) having low affinity for β-lactam antibiotics. gene is located on a mobile genetic element called staphylococcal cassette chromosome (SCC). SCC genomic island comprises two site-specific recombinase genes namely and [cassette chromosome recombinase] accountable for mobility. Currently, SCC elements are classified into types I, II, III, IV and V based on the nature of the and gene complexes and are further classified into subtypes according to variances in their J region DNA. SSC type IV has been found in community-acquired isolates with various genetic backgrounds. The present study was undertaken to categorize the types of SCC types and subtypes I, II, III, IVa, b, c, d, and V and PVL genes among clinical MRSA isolates from COVID-19 confirmed cases.

MATERIALS AND METHODS

Based on the Microbiological and Molecular ( gene PCR amplification) confirmation of MRSA isolated from 500 MRSA SCC clinical samples, 144 cultures were selected for multiplex analysis. The multiplex PCR method developed by Zhang et al. was adapted with some experimental alterations to determine the specific type of these isolates.

RESULTS

Of the total 500 MRSA, 144 MRSA (60 were CA-MRSA and 84 were HA-MRSA) were selected for characterization of novel multiplex PCR assay for SSC Types I to V in MRSA. Molecular characterization of multiplex PCR analysis revealed results compare to the phenotypic results. Of the 60 CA-MRSA; in 56 MRSA strains type IVa was found and significantly defined as CA-MRSA while 4 strains showed mixed gens subtypes. Type II, III, IA, and V were present in overall 84 HA-MRSA. Molecular subtyping was significantly correlated to define molecularly as CA-MRSA and HA-MRSA however 15 (10%) strains showed mixed genes which indicates the alarming finding of changing epidemiology of CA-MRSA and HA-MRSA as well.

CONCLUSION

We have all witnessed of COVID-19 pandemic, and its mortality was mostly associated with co-morbid conditions and secondary infections of MDR pathogens. Rapid detections of causative agents of these superbugs with their changing epidemiology by investing in typing and subtyping clones are obligatory. We have described an assay designed for targeting SSC types and subtypes I, II, III, IVa,V according to the current updated SCC typing system. Changing patterns of molecular epidemiology has been observed by this newly described assay.