Staphylococcal Enterotoxins and Toxic Shock Syndrome Toxin-1 and Their Association among Bacteremic and Infective Endocarditis Patients in Egypt

Abstract

Purpose. Infective endocarditis (IE) is a major complication in patients with bacteremia of Staphylococcus (S.) aureus infection. Our aim was to determine the association of the major Staphylococcal superantigens (SAgs), including Staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin-1 (TSST-1), among hospitalized patients diagnosed with bacteremia and those with IE. Methods. This study was conducted on 88 patients; of these, 84 (95.5%) had two positive blood cultures. Eighteen out of the 84 patients (21.4%) were diagnosed based on the modified Duke criteria by a cardiologist to have IE. The recovered isolates were screened phenotypically using ELISA followed by molecular analysis of sea, seb, sec, sed, see, and tsst-1, the major SAg coding genes, and the obtained findings were statistically analyzed. Results. Phenotypic screening for SE production of 26 selected Staphylococci (15 isolated from the IE patients (10 S. aureus and 5 coagulase negative staphylococci (CoNS)) and 11 from bacteremic patients (10 S. aureus and 1 CoNS)) using ELISA revealed that 12/26 (46%) isolates were SE producers. PCR analysis showed that 19 (73%) isolates were PCR positive for SAg genes with the highest prevalence of the sea gene (79%), followed by seb (63%) and tsst-1 (21%). The least frequent gene was sed (5.3%). Statistical correlations between bacteremic and IE isolates with respect to prevalence of SAgs showed no significant difference ( P value = 0.139, effect size = 0.572 ) indicating no specific association between any of the detected SAgs and IE. Conclusion. There is high prevalence of SEs among clinical isolates of Staphylococci recovered from patients suffering bacteremia and those with IE. No significant difference was found among Staphylococcal isolates recovered from patients with bacteremia or IE regarding both phenotypic and genotypic detection of the tested SAgs.

Phenotypic and Molecular Detection of Antiseptic Resistance Genes among Clinical Staphylococcus aureus Isolates During COVID-19 Pandemic

“…16 In the present study, S. aureus represented 11.1% of all staphylococci 17 In the current study, it was found that (84/100) 84% of isolates were confirmed to be MRSA. Our result is comparable to a recent study by Elsherif et al (2020), who reported a MRSA prevalence of 92.3% of all S. aureus isolates. 18 According to many studies, the frequency of MRSA among hospitalized patients in Egypt ranges from 50 to 82 percent.…”

“…Our result is comparable to a recent study by Elsherif et al (2020), who reported a MRSA prevalence of 92.3% of all S. aureus isolates. 18 According to many studies, the frequency of MRSA among hospitalized patients in Egypt ranges from 50 to 82 percent. 19 However, lower rates were reported in two different studies conducted Abd El-Baky et al 20 and Ahmed et al, 21 who found that methicillin resistance represented 25.4% and 15% of S. aureus isolates, respectively.…”

Host-pathogen interactions of clinical S. aureus isolates to induce infective endocarditis

“…Primers are described in supplementary table 3. PCR amplifications were performed using thermal cycler (ICycler, Bio-Rad Laboratories GmbH, Duesseldorf, Germany), with the following thermal cycling profile: initial denaturation step at 94 °C for 5 min, followed by 35 cycles of 2 min at 95 °C, 2 min annealing at 50 °C ( sea and tst ) or 57 °C ( seb and sec ) and 1 min extension at 72 °C, and final extension at 72 °C for 7 min [ 25 , 26 ]. Genomic DNA was added to PCR mix containing 1.5 mM MgCl 2 , 0.2 mM of each deoxynucleoside triphosphates, 2 pM each of forward and reverse primers and Taq polymerase (Segenetic, Borken, Germany).…”

Çeşitli Klinik Örneklerden İzole Edilen Metisiline Dirençli ve Duyarlı Staphylococcus aureus Suşlarının Toksin Profillerinin Araştırılması

“…Among the exotoxins secreted by S. aureus, staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin-1 (TSST-1) have SAg activity. These toxins are important virulence factors that contribute a variety of pathological conditions, including pneumonia, soft tissue infections, toxic shock syndrome, and infective endocarditis (2,3). Moreover, it has been recently reported that SAgs particularly SEs play a prominent role in the development of asthma of hospitalized patients via induction of IgE (4).…”