Molecular Detection of Virulence and Antimicrobial Resistance Genes of Streptococcus Pyogenes Isolated From the Oropharynx of Febrile Patients in Adama and Wonji, Ethiopia.
| dc.contributor.advisor | Negash,Abel Abera(PhD, Ass.Prof.) | |
| dc.contributor.advisor | Mihret,Adane(DMV, PhD, Ass.Prof.) | |
| dc.contributor.advisor | Adane,Kelemework(PhD, Ass.Prof.) | |
| dc.contributor.author | Lemi,Haile Abera | |
| dc.date.accessioned | 2025-08-13T07:46:29Z | |
| dc.date.available | 2025-08-13T07:46:29Z | |
| dc.date.issued | 2023-08 | |
| dc.description.abstract | Background: Streptococcus pyogenes also called Group A Streptococcus (GAS) is a significant human pathogen that causes several diseases including pharyngitis, skin infections, rheumatic fever and rheumatic heart disease. GAS produces a variety of virulence factors such as toxins/superantigens, proteases, DNases. Detection of virulence genes can be used to determine the pathogenic potential of a strain. Although GAS is generally thought to be susceptible to β-lactams, an increasing trend of treatment failures and resistance to macrolides and tetracyclines have been observed. There is a paucity of data on the molecular epidemiology of virulence factors and antibiotic-resistance of S. pyogenes in Ethiopia. Objective: To assess virulence factors, antimicrobial susceptibility profile and drug resistance genes of oropharyngeal S. pyogenes isolated from febrile patients. Method: A cross-sectional study was conducted on 201 S. pyogenes isolated from the oropharynx of febrile patients in Adama and Wonji, Oromiya, Ethiopia. Standard microbiological procedures were used for bacterial growth and identification. Bacterial DNA was extracted using an alkaline lysis buffer. Multiplex PCR was conducted to identify virulence factors for the production of superantigens (SpeA, SpeC, SpeG, SpeH, SpeI, SpeJ, SpeK, SpeL, SpeM, SmeZ and ssa); proteases (SpeB, spyCEP, scpA, Mac and sic); and DNases (sdaB, sdaD, sdc and spd3), erythromycin resistance genes [mef(A), erm(B) and erm(A)-TR] and tetracycline resistance genes [tet(M), tet(O), tet(K)and tet(L)]. SPSS version 27 was used for statistical analysis. Majority of the results were summarized by frequency and percentage distributions. Result: This study was performed on 201 S. pyogenes isolates. We investigated the presence of 20 different GAS virulence factors and identified 18 of them with variable proportions. Relatively higher frequencies of Mac (24.9%), SmeZ (16.9%), scpA (15.4%), sic (12.9%), SpeK (12.4%) and SpeI (10.0%) genes were identified. Our antibiotic susceptibility testing showed that 10% of the GAS isolates were non susceptible to penicillin. High resistance rate to tetracycline (54.2%), quinupristin-dalfopristin (43.3%) and erythromycin (19.9%) were also observed. The overall multidrug resistant (MDR) rate was 14.9%. However, all GAS isolates were 100% sensitive to linezolid. M phenotype was observed in 85% of erythromycin resistant GAS isolates and mef (A) gene was identified in 96.9% of the erythromycin non susceptible GAS isolates. Among tetracycline resistant genes tet(M) was identified in 98.2% of the tetracycline non susceptible GAS isolates. Conclusion: In this study, we have identified 121 (60.2%) of the GAS isolates had at least one or more types of virulence factors and again more than half of the isolates,156 (77.6%) were resistant to one or more types of antibiotic classes. We also found that, an emerging penicillin non susceptible GAS isolates contrary to the previous reports and this might be an alarming condition. The most common erythromycin resistance mechanism in our study was efflux pumping which was encoded by the mef(A) gene where as that of tetracycline resistance mechanism was target site modification by ribosomal protection protein which was encoded by the tet(M) gene. Linezolid may be one of the promising drugs for the treatment of drug resistant GAS strains. The identification of different virulence factors and the increasing trends of drug non susceptibility especially to penicillin among GAS isolates requires a concern for continuous surveillance of the pathogen. | |
| dc.identifier.uri | https://etd.aau.edu.et/handle/123456789/6658 | |
| dc.language.iso | en_US | |
| dc.publisher | Addis Ababa University | |
| dc.subject | Streptococcus pyogenes | |
| dc.subject | Group A Streptococci | |
| dc.subject | antibiotic sensitivity testing | |
| dc.subject | drug resistance genes | |
| dc.subject | virulence factor | |
| dc.subject | toxin | |
| dc.subject | superantigen | |
| dc.subject | Protease | |
| dc.subject | DNase | |
| dc.subject | Ethiopia | |
| dc.title | Molecular Detection of Virulence and Antimicrobial Resistance Genes of Streptococcus Pyogenes Isolated From the Oropharynx of Febrile Patients in Adama and Wonji, Ethiopia. | |
| dc.type | Thesis |