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,Ibrahim Ghoneim,Ibrahim Elsohaby,Magdy Elgioushy,Mahmoud Fayez,Mahmoud Kandeel,Theeb Al-Marri

doi:10.7717/peerj.8500

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.

Highlights

Bacteria colonizing the reproductive tract of the she-camel (Camelus dromedarius) have been reported to be the main causes of reproductive problems (Wernery & Wernery, 1992; Wernery & Kumar, 1994; Tibary et al, 2006; Ali et al, 2010)
To the authors’ knowledge, information remains limited on vaginal microbiota of camels and the potential of lactic acid bacteria (LAB) isolates to be used as probiotics in camels
In dairy cows, the use of LAB as probiotics lowered the incidence of infections in uterus and enhanced the local and systemic immune reactions of treated cows (Kummer et al, 1997; Deng et al, 2015)

Summary

Introduction

Bacteria colonizing the reproductive tract of the she-camel (Camelus dromedarius) have been reported to be the main causes of reproductive problems (Wernery & Wernery, 1992; Wernery & Kumar, 1994; Tibary et al, 2006; Ali et al, 2010). Camel endometritis is a major cause of infertility of camels in Saudi Arabia. About 57.1% of cases with reproductive disorders were due to metritis and endometritis (Ali et al, 2010). Owing to the diversity of these pathogens, a single antibiotic program might not be sufficient due to the bacterial resistance and the broad range of bacterial species. Probiotics have been introduced as a novel strategy for the treatment program and preventive measures of reproductive tract diseases (Reid & Burton, 2002). Different definitions have been reported for probiotics based on the mechanisms and site of action, delivery format and method, and host. The internationally recognized meaning of probiotics is “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host” (FAO/WHO, 2001; Sanders, 2008)

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