Characterization of drug-resistant Streptococcus spp. from food and human sources and in vitro antibacterial assessment of an oregano nanoemulsion

IF 5.1 4区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Annals of Microbiology Pub Date : 2026-05-18 DOI:10.1186/s13213-026-01857-7

Nady Khairy Elbarbary, Neveen M. Abdelmotilib, Marwa O. Abd El-Halim, Doaa A. Abdallah, Yehia Hazzazi, Mari Sumayli, Ramadan Taha, Latifa Al Husnain, Muneera D. F. Alkahtani, Ahmed Ezzat Ahmed, Sohaila F. El-Hawary, Marwa M. Abdallah, Basma Gamal

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Abstract

Abstract Objectives This study aimed to characterize drug-resistant Streptococcus spp. isolated from food and human sources in Upper Egypt, focusing on their virulence and antimicrobial resistance profiles, and to evaluate the in vitro antibacterial activity of an oregano essential oil nanoemulsion. Materials and methods A total of 440 food and human samples were collected in Aswan, Upper Egypt, and screened using conventional microbiological methods. Molecular confirmation was performed by detecting the tuf gene, followed by species identification using the 16 S rRNA and spn9802 genes. Selected virulence ( scpB , Rib , Lmb , and cylE ) and resistance ( aac6-aph2 , pbp1A , and tetO ) genes were detected by PCR. Antimicrobial susceptibility testing and the multiple antibiotic resistance (MAR) index were determined. The antibacterial activity of the oregano nanoemulsion was assessed using inhibition zone assays at varying concentrations. Results Streptococcus spp. were detected in 22% of samples, with higher prevalence in throat swabs (34%) and raw milk (21.9%). Predominant species included S. agalactiae , S. pyogenes , S. dysgalactiae , S. pneumoniae , and S. uberis . Virulence genes were variably distributed, with scpB (33%) and cylE (31.8%) most frequent. Resistance genes were moderately detected, particularly tetO (21.2%). Most isolates were resistant to β-lactams but fully susceptible to ceftaroline and fosfomycin; the mean MAR index was 0.477. The oregano nanoemulsion showed concentration-dependent antibacterial activity. Conclusion Drug-resistant Streptococcus spp. from food and human sources in Upper Egypt carry important virulence and resistance determinants. The oregano essential oil nanoemulsion demonstrated promising in vitro antibacterial activity, suggesting potential as a natural antimicrobial; however, further in vivo and safety studies are required.

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食物和人源耐药链球菌的鉴定及牛至纳米乳的体外抗菌评价

摘要：目的研究上埃及地区从食物和人体内分离的耐药链球菌，研究其毒力和耐药性特征，并评价牛至精油纳米乳的体外抗菌活性。材料与方法在上埃及阿斯旺地区采集440份食品和人体样本，采用常规微生物学方法进行筛选。通过检测tuf基因进行分子鉴定，然后利用16s rRNA和spn9802基因进行物种鉴定。选择毒力基因（scpB、Rib、Lmb和cycle）和抗性基因（aac6-aph2、pbp1A和tetO）进行PCR检测。进行药敏试验和多重抗生素耐药（MAR）指数测定。采用抑菌带法测定不同浓度牛至纳米乳的抑菌活性。结果22%的样本中检出链球菌，其中咽拭子和原料奶的检出率较高，分别为34%和21.9%。优势种包括无乳链球菌、化脓性链球菌、无乳链球菌、肺炎链球菌和uberis。毒力基因分布不均匀，以scpB（33%）和cycle（31.8%）最为常见。耐药基因较多，以tetO为主（21.2%）。多数菌株对β-内酰胺类耐药，但对头孢他林和磷霉素完全敏感；平均MAR指数为0.477。牛至纳米乳具有浓度依赖性的抗菌活性。结论上埃及地区食物和人源耐药链球菌具有重要的毒力和耐药性决定因素。牛至精油纳米乳具有良好的体外抗菌活性，具有天然抗菌剂的潜力；然而，还需要进一步的体内和安全性研究。

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来源期刊

Annals of Microbiology 生物-生物工程与应用微生物

CiteScore

6.40

自引率

0.00%

发文量

审稿时长

3.2 months

期刊介绍： Annals of Microbiology covers these fields of fundamental and applied microbiology: general, environmental, food, agricultural, industrial, ecology, soil, water, air and biodeterioration. The journal’s scope does not include medical microbiology or phytopathological microbiology. Papers reporting work on bacteria, fungi, microalgae, and bacteriophages are welcome. Annals of Microbiology publishes Review Articles, Original Articles, Short Communications, and Editorials. Originally founded as Annali Di Microbiologia Ed Enzimologia in 1940, Annals of Microbiology is an official journal of the University of Milan.

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