Isolation and characterization of vaginal Lactobacillus spp. in dromedary camels (Camelus dromedarius): in vitro evaluation of probiotic potential of selected isolates

Wael M El-Deeb; Mahmoud Fayez; Ibrahim Elsohaby; Ibrahim Ghoneim; Theeb Al-Marri; Mahmoud Kandeel; Magdy ElGioushy

doi:10.7717/peerj.8500

Isolation and characterization of vaginal Lactobacillus spp. in dromedary camels (Camelus dromedarius): in vitro evaluation of probiotic potential of selected isolates

PeerJ. 2020 Feb 5:8:e8500. doi: 10.7717/peerj.8500. eCollection 2020.

Authors

Wael M El-Deeb^{1

2}, Mahmoud Fayez^{3

4}, Ibrahim Elsohaby^{5

6}, Ibrahim Ghoneim^{1

7}, Theeb Al-Marri¹, Mahmoud Kandeel^{8

9}, Magdy ElGioushy¹⁰

Affiliations

¹ Department of Clinical Sciences, College of Veterinary Medicine, King Faisal University, Al-Ahsa, Saudi Arabia.
² Department of Veterinary Medicine, Infectious Diseases and Fish Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt.
³ Ministry of Agriculture, Al-Ahsa Veterinary Diagnostic Laboratory, Al-Ahsa, Saudi Arabia.
⁴ Veterinary Serum and Vaccine Research institute, Ministry of Agriculture, Cairo, Egypt.
⁵ Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Sharkia Governorate, Egypt.
⁶ Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Canada.
⁷ Department of Theriogenology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
⁸ Department of Biomedical Sciences, College of Veterinary Medicine, King Faisal University, Al-Ahsa, Saudi Arabia.
⁹ Department of Pharmacology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafr Elsheikh, Egypt.
¹⁰ Department of Animal Medicine, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt.

Abstract

Lactobacillus spp. is one of the beneficial lactic acid producing microbiota in the vagina, which is important for a healthy vaginal environment. However, little is known about vaginal Lactobacillus in dromedary camels (Camelus dromedarius). Therefore, this study aimed to isolate vaginal lactic acid bacteria (LAB) in dromedary camels and to study the probiotic potential of selected isolates. A total of 75 vaginal swabs were collected from pluriparous, non-pregnant, non-lactating dromedary camels. The LAB were isolated using deMan, Rogosa and Sharpe broth and agar media. Suspected LAB isolates were subjected to catalase testing and Gram staining and examined for indole production, nitrate reduction, hemolytic activity, cell surface hydrophobicity, auto- and coaggregation, antibacterial activity and characterized by 16S rRNA amplification and sequencing. Eighteen LABs were isolated from the 75 vaginal swabs. Among the 18 LAB isolates, six were Lactobacillus plantarum, eight were Lactobacillus fermentum, and four were Lactobacillus rhamnosus. None of the LAB isolates was hemolytic and only four LAB were H₂O₂ producing. The percentage of hydrophobicity ranged from 0% to 49.6%, 0% to 44.3% and 0% to 41.6% for hexadecane, xylene and toluene, respectively. All isolates showed higher (P < 0.05) autoaggregation after 24 h of incubation compared to 4 h. Furthermore, all LAB showed higher coaggregation (P < 0.05) and antimicrobial activity toward Staphylococcus aureus than to Escherichia coli. All LAB isolates were vancomycin resistant and sensitive to streptomycin, erythromycin, kanamycin and chloramphenicol. Only, three LAB isolates were resistant to tetracycline. The dromedary camel vaginal LAB isolates exhibited varying degrees of in vitro probiotic properties tested in this study and showed promising activity against the most common bacterial causes of endometritis in dromedary camels. Further investigation of the in vivo effect of these isolates is warranted.

Keywords: 16S rRNA; Antimicrobial; Autoaggregation; Coaggregation; Endometritis; Infection; Lactobacillus fermentum; Lactobacillus plantarum; Lactobacillus rhamnosus; Uterus.

Grants and funding

This work was supported by the Deanship of Scientific Research at King Faisal University, Grant No. 17122001. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.