Abstract
Purpose: :
To determine the presence of SCCmec types and Panton-Valentine Leukocidin toxin among ocular Staphylococcus aureus isolates.
Methods: :
A multiplex PCR assay with seven primer sets was used to characterized SCCmec (I-IV) types among nonrandom Staphylococcus aureus (N=62, MRSA-53 and MSSA-9) collected within the last 5 years. Separate PCR assays were run to confirm the presence of the mecA gene and detect the PVL gene locus. SCCmec types and PVL genes were correlated with isolate origin (Community vs Healthcare), ocular source and presence of fluoroquinolone resistance.
Results: :
Both healthcare acquired (HA-MRSA) SCCmec types (, I, II, III, N=21, 39.6%) and community-acquired (CA-MRSA, N=32, 60.4%, IV) were documented among these MRSA isolates. The PVL toxin was documented in 39 (62.9%) of the 62 total isolates. Among the MRSA isolates, PVL toxin was most frequently associated with SCCmec type IV (61.5%, 24/39), followed by SCCmec type II (17.9%, 7/39). The PVL gene was documented in 8/9 (88.9%) of the MSSA isolates. Ocular sources included conjunctiva (45.2%, N=28), lids (21%, N=13), lacrimal sac (11.3%, N=7), cornea (6.5%, N=4), IOF (4.8%, 3) and others (11.3%, N=7). Community acquired SCCmec type IV was most commonly associated with conjunctiva (N=17, 53.1%) and lids (N=9, 28.1%) isolates. The 4 cornea isolates were SCCmec II. 95% of SCCmec types (I-III) were resistant to ciprofloxacin vs 69% for SCCmec type IV. Results for moxifloxacin resistance was 71% and 64% respectively.
Conclusions: :
The predominant profile for ocular MRSA isolates among this group was SCCmec IV (CA-MRSA) harboring the necrotizing PVL toxin gene with high level fluoroquinolone resistance. Understanding the source and profile of ocular MRSA can aid in therapeutic management and infection prevention strategies.
Keywords: bacterial disease • gene screening • microbial pathogenesis: clinical studies