Molecular Characterization of Isolates Associated with Nasal Colonization and Environmental Contamination in Academic Dental Clinics.

To determine the genetic makeup of methicillin-sensitive/methicillin-resistant (MSSA/MRSA) from nasal colonization and environmental contamination in dental clinics. Nasal swabs from students and health care workers and environmental swabs were obtained at two academic dental clinics in the United Arab Emirates. The StaphyType DNA microarray-based assay was used for molecular characterization. Forty-eight isolates were identified phenotypically (nasal:  = 43; environmental:  = 5), but 6 of these were assigned to by genotyping. These were CC2596, CC2250-MSSA, CC2250-MSSA-(Panton Valentine leukocidin [PVL]+) ( = 2), and CC2198-MSSA ( = 2). MRSA nasal colonization rate was 5.4% (n/ = 8/146) with the following strain affiliations: CC5-MRSA-[IV++], "Maltese Clone"; CC6-MRSA-IV, "WA MRSA-51"; CC22-MRSA-IV (PVL+/); CC22-MRSA-[IV+]; and two each of CC5-MRSA-[VI+] and CC97-MRSA-[V/VT+]. The SCC-borne fusidic acid resistance () gene was detected in MRSA ( = 5) and MSSA ( = 1). Some MSSA strains, CC1-MSSA-[+] and ST1278-MSSA-[], harbored recombinase genes. A CC30-MSSA harbored ACME locus/-genes, while ST1278-MSSA-[] had an ACME-III element. Enterotoxin genes were commonly carried, but gene was found in only CC22, CC30, and CC34 strains, while genes were identified in CC2250 and CC22-MRSA-IV. Of the 51 noncoagulase staphylococci (CoNS) identified, 18 were positive. The findings demonstrate the first report of rare strains (ST1278 MSSA, CC2198, CC2596, and PVL+CC2250) in our region. Detection of MSSA with recombinase genes and ACME loci alongside -positive CoNS is of clinical significance as this could provide a milieu for acquisition and transfer of SCC-elements, either with different ACME types, with or the gene resulting in conversion of MSSA into MRSA.