Genetic Lineages of Methicillin-Resistant Staphylococcus aureus Acquired during Admission to an Intensive Care Unit of a General Hospital

Superior Ophthalmic Vein Thrombosis: A Case Report in a Previously Healthy Methicillin-Resistant Staphylococcus aureus-Positive Patient

BACKGROUND Superior ophthalmic vein thrombosis (SOVT) is a rare condition, with an incidence of 3 to 4 cases per million per year. SOVT can be classified according to the underlying etiology into septic or aseptic SOVT. We present a case of right SOVT in a previously healthy patient with a positive blood culture of methicillin-resistant Staphylococcus aureus (MRSA). CASE REPORT A previously healthy 38-year-old female patient presented with a 2-week history of worsening right-sided headache associated with photophobia, phonophobia, right-sided ear pain, and tinnitus. The best corrected visual acuity was 6/12 in the right eye and 6/6 in the left eye. Ophthalmic examination revealed right eye upper lid edema, proptosis, and diplopia in all gazes, mainly vertical. The fundus examination showed a raised hyperemic right optic disc with blurred margins. Laboratory investigations showed a positive blood culture of MRSA and elevated levels of inflammatory markers erythrocyte sedimentation rate and C-reactive protein. Orbital computed tomography examination showed periorbital and orbital cellulitis with superior ophthalmic vein thrombosis. The patient was treated successfully with antibiotics and anticoagulants. At 1-month follow-up, the patient was compliant with medications and reported full resolution of symptoms, with no visual acuity impairment. CONCLUSIONS SOVT is a challenging ophthalmic condition and can be present concurrent with orbital cellulitis or cavernous sinus thrombosis. Early imaging studies and proper management are important to prevent serious complications. Ophthalmologists need to be alerted of the importance of tailoring antibiotics based on the causative agent, to decrease the risk of therapeutic failure and microbial resistance.

Relationship between mortality and molecular epidemiology of methicillin-resistant Staphylococcus aureus bacteremia

Staphylococcus aureus is the primary cause of bacteremia, and methicillin-resistant S. aureus bacteremia is associated with a high mortality rate. Methicillin-resistant S. aureus clones are widespread worldwide, and molecular epidemiological studies are important. Therefore, this study aimed to determine the characteristics of patients who died due to methicillin-resistant S. aureus bacteremia and microbiological characteristics of methicillin-resistant S. aureus strains in a tertiary teaching hospital. This single-center, retrospective study included patients with methicillin-resistant S. aureus isolated from blood bacterial culture performed at Kyoto Prefectural University of Medicine Hospital, from October 2016 to May 2019. The data analyzed included patient background, clinical strain characteristics, and molecular epidemiology. Of 41 patients with methicillin-resistant S. aureus bacteremia (median age, 60 [28–70] years; 24 (59%) were men), and 7 (17%) died due to methicillin-resistant S. aureus bacteremia. The median age of those who died in the methicillin-resistant S. aureus bacteremia group was predominantly higher than that of those in the alive group (p = 0.03). The most common cause of methicillin-resistant S. aureus bacteremia was endovascular devices, which occurred in 20 (49%), 18 (53%), and 2 (29%) patients in the total, alive, and died groups, respectively. Bacteriological characteristics showed that type IV Staphylococcal Cassette Chromosome mec genotype was most frequently detected in the total (n = 34 [83%]), alive (n = 29 [85%]), and died (n = 5 [71%]) groups. In the molecular cluster analysis, CC8, ST8, staphylococcal Cassette Chromosome mec type IV, and community-acquired-methicillin-resistant S. aureus formed the largest groups. The diversity of methicillin-resistant S. aureus clones is evident, and it is possible that clones with new virulence factors may still emerge. In the future, it will be crucial to monitor the epidemiological trends of methicillin-resistant S. aureus to respond quickly to changes in pathogenic and clonal factors, to clarify the gene expression network by identifying old and new virulence factors.

Epidemiology of Methicillin-Resistant Staphylococcus Aureus in Arab Countries of the Middle East and North African (MENA) Region

Available data suggest a high burden of methicillin-resistant staphylococcus aureus (MRSA) in Arab countries of the Middle East and North Africa (MENA). To review the MRSA rates and molecular epidemiology in this region, we used PubMed search engine to identify relative articles published from January 2005 to December 2019. Great heterogeneity in reported rates was expectedly seen. Nasal MRSA colonization ranged from 2%–16% in Gulf Cooperation Council (GCC), 1–9% in the Levant, and 0.2%–9% in North African Arab states. Infective MRSA rates ranged from 9%–38% in GCC, 28%–67% in the Levant, and 28%–57% in North African states. Studies demonstrated a wide clonal diversity in the MENA. The most common molecular types belonged to 5 clonal complexes (CC) known to spread worldwide: CC5, CC8, CC22, CC30, and CC80. The most prevalent strains had genotypes related to the European community-acquired MRSA (CA-MRSA), Brazilian/Hungarian hospital-acquired MRSA (HA-MRSA), UK-EMRSA-15 HA-MRSA, and USA300 CA-MRSA. Finally, significant antimicrobial resistance was seen in the region with variation in patterns depending on location and clonal type. For a more accurate assessment of MRSA epidemiology and burden, the Arab countries need to implement national surveillance systems.

Methicillin-Resistant Staphylococcus aureus ST80 Clone: A Systematic Review

This review assessed the molecular characterization of the methicillin-resistant Staphylococcus aureus (MRSA)-ST80 clone with an emphasis on its proportion of total MRSA strains isolated, PVL production, spa-typing, antibiotic resistance, and virulence. A systematic review of the literature was conducted on MRSA-ST80 clone published between 1 January 2000 and 31 August 2019. Citations were chosen for a review of the full text if we found evidence that MRSA-ST80 clone was reported in the study. For each isolate, the country of isolation, the sampling period, the source of isolation (the type of infection, nasal swabs, or extra-human), the total number of MRSA strains isolated, number of MRSA-ST80 strains, antibiotic resistance patterns, PVL production, virulence genes, and spa type were recorded. The data from 103 articles were abstracted into an Excel database. Analysis of the data showed that the overall proportion of MRSA-ST80 has been decreasing in many countries in recent years. The majority of MRSA-ST80 were PVL positive with spa-type t044. Only six reports of MRSA-ST80 in extra-human niches were found. This review summarizes the rise of MRSA-ST80 and the evidence that suggests that it could be in decline in many countries.

Molecular Characterization of Methicillin- Resistant Staphylococcus aureus in a Tertiary Care hospital in Kuwait

Methicillin-resistant Staphylococcus aureus (MRSA) are a major cause of healthcare and community- associated infections due to their ability to express a variety of virulence factors. We investigated 209 MRSA isolates obtained from 1 January to 31 December 2016 using a combination of phenotypic and genotypic methods to understand the genetic backgrounds of MRSA strains obtained in a General hospital in Kuwait. Antibiotics susceptibility was performed with disk diffusion, and MIC was measured with Etest strips. Molecular typing was performed using SCCmec typing, spa typing, and DNA microarray for antibiotic resistance and virulence genes. The isolates were susceptible to vancomycin, teicoplanin, rifampicin, ceftaroline, and linezolid but were resistant to gentamicin, tetracycline, erythromycin, fusidic acid, chloramphenicol and ciprofloxacin. Molecular typing revealed six SCCmec types, 56 spa types and 16 clonal complexes (CC). The common SCCmec types were type IV (39.5%), type III (34.4%), type V (25.8%) and type VI (3.8%). The dominant spa types were t860 (23.9%), t945 (8.6%), t127 (6.7%), t688 (6.7%), t304 (6.2) and t044 (5.7%). The other spa types occurred sporadically. Genes for PVL was detected in 59 (28.2%) of the isolates. CC8-ST239-MRSA-III + SCCmer (23.3%) was the most prevalent clone, followed by CC6-MRSA-IV (8.3%), CC80-MRSA-IV [PVL+] (5.8%), CC5-MRSA-VI + SCCfus (5.0%), CC30-MRSA-IV[PVL+] (4.1%), CC1-MRSA-V + SCCfus [PVL+] (4.1%), CC5-MRSA-V + SCCfus (4.1%) and CC22-MRSA-IV[PVL+] (4.1%). The study revealed that despite the emergence of MRSA with diverse genetic backgrounds over the years, ST239-MRSA-III remained the dominant clone in the hospital. This warrants reassessment of infection prevention and control procedures at this hospital.