Prevalent virulent genes among methicillin resistant Staphylococcus aureus isolates from community settings in Trinidad and Tobago

Abstract

Background:The symptoms of viral and bacterial sore throats are similar, making it difficult to distinguish between them using clinical features alone. We evaluated the Clinical Assessment of Strep Throat (CAST) for predicting beta-haemolytic streptococcal infection. Results were compared to throat cultures that provide a definitive streptococcal diagnosis.Methods & Materials: A total of 440 patients with recent-onset sore throat due to upper respiratory tract infection were randomised to receive a single dose of flurbiprofen 8.75 mg delivered as a spray or lozenge. Using the patient's history, symptoms and physical findings, investigators performed the CAST to make a clinical judgement on the likelihood of streptococcal infection using a 4-point categorical scale (unlikely [-1], uncertain [0], likely [1], very likely [2]). Throat swabs for culture identified patients with Strep A or C infection (n = 433).Results: Streptococcal infection was considered 'very likely' in one patient, 'likely' in 78 patients (18.0%), 'uncertain' (ie a lack of diagnosis) in 123 patients (28.4%) and 'unlikely' in 231 patients (53.3%). Overall, 25 patients had Strep A-or C-positive throat cultures; of these only 8 were considered 'likely' or 'very likely' to have a streptococcal infection using the CAST. The sensitivity and specificity of the CAST was 32% and 55.9%, respectively. The misclassification rate (clear errors in prediction) was 17.1%. However, a trend test showed the 'likely' and 'very likely' categories were associated with higher probability of streptococcal infection (p = 0.0003). Conclusion:While the number of Strep A or C cases was relatively low, these results clearly show the difficulty in predicting the likelihood of infection based on clinical features alone. Of the 79 patients identified as 'likely'/'very likely' to have a streptococcal infection using the CAST, 71 patients could have potentially received antibiotics inappropriately. Such a large proportion is critical, as inappropriate antibiotic usage contributes to the global problem of antibiotic resistance. Flurbiprofen is an alternative to inappropriate antibiotics and in this study provided symptomatic relief in patients with or without streptococcal infection.Conflicts of interest: Reckitt Benckiser funded this study. Adrian Shephard and Valeria Bychkova are employees of Reckitt Benckiser, and Natalia Burova's organisation received Reckitt Benckiser funding for the study.

Determination of the frequency, species distribution and antimicrobial resistance of staphylococci isolated from dogs and their owners in Trinidad

“…Using the disc diffusion method, no MRSA were observed amongst the isolates from pet canines or their owners. This finding is in agreement with the fact that MRSA colonization in the community in Trinidad and Tobago [69] and other countries [70] is low. Additionally, studies investigating MRSA in households indicates that pets in households where owners were positive were more likely to be MRSA-positive [71].…”

Prevalence and genotypic characteristics of Panton-Valentine Leukocidin-producing Staphylococcus aureus isolates obtained in Jos, North Central Nigeria

“…Similarly, PVL-positive strains accounted for 36% of S. aureus investigated in a study in USA [24]. Our result was lower than the proportion of PVL-positive S. aureus reported in Maiduguri, North East Nigeria (52.1%) [13]; the 61.4% in the Gambia [25], the 58% in Sudan [26], the 73.91% in Colombia [27], the 61.5% in India [28], the 56.2% in Iran [29], the 46.3% in Kazakhstan [30] and the 62.5% in Trinidad and Tobago [31]. In contrast, our result was higher than the prevalence of PVL-positive strains reported from several other studies in Abuja, Nigeria that reported a prevalence of 10.7% among isolates obtained from Maitama District Hospital [14], the 12.7% prevalence reported in Kuwait [8], the 23% reported in Iran [32] and the 18.6% prevalence reported in Brazil [33].…”

Eleutheroside K Isolated from Acanthopanax henryi (Oliv.) Harms Inhibits the Expression of Virulence-Related Exoproteins in Methicillin-Resistant Staphylococcus aureus

“…We speculate that ETSK suppresses the expression of genes encoding S. aureus exotoxin downstream of agrA by inhibiting the gene expression of the agr regulatory system. Due to the down-regulation of agrA gene expression, we have sufficient reasons to infer that the expression of S. aureus exotoxins regulated by RNAIII will be suppressed at both gene and protein levels [38,39]. As a factor that activates RNAIII expression, the downward trend of agrA gene expression is consistent with the inhibition of α-hemolysin and SEs as expected.…”