Identification of Major Sequence Types among Multidrug-Resistant Staphylococcus epidermidis Strains Isolated from Infected Eyes and Healthy Conjunctiva

Abstract

We examined the presence of virulence and antibiotic resistance genes, SCCmec types and determined the genomic diversity among ocular S. epidermidis isolates (patients-23, healthy controls-29). PCR determined the presence of antibiotic resistance genes, virulence genes and SCCmec types among all isolates. MLST and PFGE determined the genomic relatedness among them. All isolates of S. epidermidis showed resistance to at least one class of antibiotics of which 48 isolates were multidrug resistant and carried ARGs. Thirty-five isolates were methicillin resistant and carried mecA gene. Majority of the isolates were resistant to fluoroquinolones and showed mutation in gyrA, parC, and parE genes, however, few isolates showed additional novel mutations in parC gene. Of the MRSE strains, 17 strains carried SCCmec type IV, four type V, two type II, and two UT4. Seven strains carried novel combination of ccr complex and SCCmercury element, not reported earlier. All the S. epidermidis strains harbored icaA and icaD genes, 47 carried ACME operon, and 50 contained IS256. A noteworthy finding was the presence of ST179 among 43% of infected eye isolates an observation rarely reported among S. epidermidis. PFGE and MLST analysis showed genomic diversity among them. Statistical analysis suggests that few healthy conjunctiva isolates had characteristics similar to infected eye isolates. S. epidermidis strains carrying mecA gene are multidrug resistant, virulent and diverse irrespective of sources of isolation. IS256 cannot be used as marker to differentiate isolates of infected eye from healthy conjunctiva.

Molecular Epidemiology of Staphylococcus epidermidis Implicated in Catheter-Related Bloodstream Infections at an Academic Hospital in Pretoria, South Africa

“…The IS 256, ica AB, and qac A/B genes were also highly prevalent among these isolates. All S. epidermidis isolates carried the mec A gene, which is similar to a study conducted in China (~96%) (Li et al, 2009 ), but higher compared to a study done in Portugal (~70%) (Rolo et al, 2012 ) and India (~67%) (Jena et al, 2017 ). The high degree of antimicrobial resistance and the presence of the mec A gene may indicate the presence of methicillin-resistant S. epidermidis (MRSE), which is more often resistant to other antimicrobials compared to methicillin-sensitive S. epidermidis (Otto, 2009 ).…”

“…The hospital environment is known to play a fundamental role in the amplification and the diversification of SCC mec elements in S. epidermidis (Rolo et al, 2012 ). S. epidermidis harbouring multiple ccr and mec gene complexes have been extensively reported in the literature (Ibrahem et al, 2008 ; Garza-González et al, 2010 ; Svensson et al, 2011 ; Zong et al, 2011 ; Rolo et al, 2012 ; Jena et al, 2017 ), but none of these studies have addressed the possibility of polyclonality. Polyclonality among S. epidermidis isolates has been reported in prosthetic joint infections (Galdbart et al, 1999 ), prosthetic valve endocarditis (Van Wijngaerden et al, 1997 ; Jena et al, 2017 ), healthy ocular surfaces (Ueta et al, 2007 ), and CRBSI (Rijnders et al, 2001 ).…”

An Evaluation of Staphylococci from Ocular Surface Infections Treated Empirically with Topical Besifloxacin: Antibiotic Resistance, Molecular Characteristics, and Clinical Outcomes

“…Recent publications suggest that resistance and virulence may be converging and that SCCmec types associated with community-acquired staphylococci are now exhibiting increased antibiotic resistance [16,19,20,28,[40][41][42]. Despite the predominance of SCCmec types IV/V among MRSE in the current study (n = 6), nearly all (83%) showed MDR.…”

“…These findings are consistent with those from an analysis of 30 MRSE isolates from ocular infections in Sao Paulo, Brazil, which found that of 17 isolates containing SCCmec IV/V, at least 70% were MDR [19]. Similarly, Jena et al examined the molecular traits of 52 ocular S. epidermidis isolates (23 from infections and 29 from asymptomatic healthy conjunctiva) in India and determined that all isolates containing SCCmec IV/V (10 from infections; 11 from healthy conjunctiva) were MDR [20]. Consistent with results reported from health-care settings, an analysis of 643 staphylococci isolated from environmental samples in a community in the UK found that of 46 CoNS isolates for which SCCmec types were determined, 18 were type IV/V, and 16 of these demonstrated resistance to 3 or more antibiotics [40].…”

“…Cytotoxins such as Panton-Valentine leukocidin (PVL) enhance pathogenicity [12,15,17], and MRSA isolates carrying SCCmec IV are known to also harbor the PVL gene [18]. Similar studies have begun to evaluate the resistance traits of methicillin-resistant S. epidermidis (MRSE) isolates from ocular infections [19,20].…”