Epidemiology, Drug Resistance, and Virulence of Staphylococcus aureus Isolated from Ocular Infections in Polish Patients

Abstract

Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.

Virulence Genes of Staphylococcus aureus Associated With Keratitis, Conjunctivitis, and Contact Lens–Associated Inflammation

“… 76 Additionally, the prevalence of S. aureus virulence factors such as pvl , enterotoxin E ( sea ) or leucocidin E ( LukE ), among ocular isolates, have demonstrated that pvl and lukE were found in majority of ocular strains, whereas sea was less common. 78 , 79 However, a recent study showed that the enrichment of enterotoxin superantigens in S. aureus ocular strains when compared with nonocular S. aureus strains. 80 …”

Antibiotic Resistance Pattern of Staphylococcus Aureus Isolated From Pediatrics With Ocular Infections: A 6-Year Hospital-Based Study in China

“…However, there have been few literatures focusing on pediatrics. In the studies involving a broader age range (from infant to elderly), the percentage of MRSA varies a lot: the rates were high in the Ocular TRUST3 study (48.1%, 2007-2008) and the latest ARMOR study (20,24), both of which were conducted in United States; the rates were extremely low in Canada (6.4%, 2000-2010) and Polish (6.0%, 2009-2013) (25,26); and for surveys in Asia, a similar rate of 21% was demonstrated in India (2007-2017) (27), a higher rate of 56.8% in Shanghai (6 year study, uncertain) and 52.8% in Taiwan (1999-2008) (17,28), and a lower rate of 12.5% In Hong Kong (2005-2015) (18). In general, the rates of S. aureus cultured positive for MRSA over the world were variable depending on geography and year of study, and most of the rates were relatively high throughout the past two decades; more attention should be paid to it.…”

“…However, no difference of MRSA proportion was found in children under 1 year of age compared to those beyond, and MRSA colonized in conjunctival sac did not seem to cause severe ophthalmic infection to the newborn (4). Even so, conjunctival MRSA infection should not be underestimated in infants because the virulence of MRSA changes (26,30), and infants are extremely susceptible to bacterial infection due to their pre-matured immune system.…”

“…Sensitivity to fluoroquinolones differs by the agent generations and the countries (26,38); our study showed extremely low resistance against ciprofloxacin and levofloxacin among MRSA (7.1, 2.8%), much lower than that from the pediatric ARMOR study (40.6-42.0% for fluoroquinolones) (13), and lower than that from the study of Hong in Shanghai, China, which was not limited to children (60.3, 68.6%) (28). Levofloxacin, one of the most commonly used eye drops for pediatrics in China, was found to be more sensitive to ocular MRSA infections than in the United States.…”

Genomics of Staphylococcus aureus ocular isolates

“…For example, multilocus sequence typing (MLST), which compares the genetic sequences of seven housekeeping genes (arcC, aroE, glpF, gmk, pta, tpi, and yqiL) to identify sequence types (STs), has revealed ST5, ST8, ST15, ST30, ST59, and ST772 as common among specific S. aureus ocular strain sets [13][14][15][16]. Additionally, studies to assess the prevalence of S. aureus virulence factors among ocular isolates such as Panton-Valentine Leukocidin (pvl), Enterotoxin E (sea) or Leukocidin E (lukE) have demonstrated that while pvl and lukE are found in the majority of sampled ocular strains, sea may be less common [16,17]. While this initial work has provided insight into the genetic characteristics of ocular S. aureus clinical isolates, they have largely been limited to small sample sizes and a handful of virulence factors.…”