Genomic sequencing of nasal colonizing MSSA with or without the CzIE isolated from Colombian ICU patients

While infections by Methicillin-Resistant Staphylococcus aureus (MRSA) have been significant due to their difficult treatment, in recent years a higher proportion of invasive infections by Methicillin-Sensitive S. aureus (MSSA) have been evidenced in different countries, including Colombia. For over a decade, it has been reported that some MSSA clinical isolates present a phenomenon called Cefazolin inoculum effect (CzIE), which could limit the therapeutic efficacy of cefazolin during the treatment of MSSA infections (first-line treatment). The CzIE has been broadly described in MSSA clinical isolates. However, there is a lack of knowledge of the CzIE in nasal colonizing MSSA isolates and their genetic background. Therefore, we sequenced a set of nasal colonizing MSSA with and without the CzIE to characterize genotypically this phenomenon in colonizing MSSA recovered from the nasal cavity of patients in Intensive Care Units (ICU) from Colombia.