Abstract
Purpose:
To determine the presence of SCCmec types and Panton-Valentine Leukocidin toxin among random vitreous and anterior chamber Staphylococcus aureaus isolates.
Methods:
A multiplex PCR assay with six primer sets was used to characterize SCCmec Types I-IV among random vitreous (Vit) and anterior chamber (A/C) Staphylococcus aureaus isolates (N= 36, MRSA-8, and MSSA-28) collected between 1990 and 2012. 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 (CA-MRSA v. HA-MRSA) and ocular source.
Results:
Both healthcare-acquired (HA-MRSA) SCCmec types (I, II, III, N= 2, 25%) and community-acquired (CA-MRSA) SCCmec types (IV, N= 1, 12.5%) were documented among the MRSA isolates. 5/8 (62.5%) of the MRSA isolates were nontypeable for the SCCmec types. The PVL toxin was documented in 15/36 (41.7%) of the total isolates; it was found in 3/8 (37.5%) of MRSA isolates and in 12/28 (48.9%) of MSSA isolates. Of the typeable MRSA isolates, the PVL toxin was documented in 2/3 (66.7%), 1/2 (50%) of type II SCCmec and 1/1 (100%) of SCCmec type IV. Among MRSA isolates, the PVL toxin was most frequently associated with SCCmec type II (2/8, 25%), followed by SCCmec type IV (1/8, 12.5%). Ocular sources included vitreous (Vit, 11/36, 30.6%) and anterior chamber (A/C, 25/36, 69.4%). 2/8 (25%) of MRSA isolates originated from A/C, while 6/8 (75%) of MRSA isolates originated from Vit. Of the MRSA typeable isolates (N=3, 83.3%), 2/2 (100%) of the HA-MRSA isolates (type II) originated from A/C and 1/1 (100%) of the CA-MRSA (types IV) originated from Vit.
Conclusions:
The predominant profile for ocular MRSA isolates among this group was SCCmec type II (HA-MRSA). While the majority of the typeable MRSA isolates harbored the PVL toxin, a conclusion about which SCCmec subtypes predominantly harbor the PVL toxin cannot be made from this population of isolates. Understanding the profile of ocular MRSA will provide the opportunity to further explore the presence of the PVL toxin in MRSA subtypes correlating with both healthcare-acquired and community-acquired MRSA infection. Future study involves assessing the level of various antibiotic resistances in order to aid in the prevention and management of intraocular MRSA infection.
Keywords: 720 Staphylococcus