Panoramic MLVA fingerprinting of Brucella melitensis circulating among livestock and cases of sporadic human illness in Egypt

Authors: SAYOUR, ASHRAF - Animal Health Research Institute; ELBAUOMY, ESSAM - Animal Health Research Institute; ABDEL-HAMID, NOUR - Animal Health Research Institute; MAHROUS, AYMAN - General Organization For Veterinary Services (GOVS); Carychao, Diana; Cooley, Michael; ELHADIDY, MOHAMED - Zewail City Of Science And Technology

Submitted to: Transboundary and Emerging Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2020
Publication Date: 4/18/2020
Citation: Sayour, A.E., Elbauomy, E., Abdel-Hamid, N.H., Mahrous, A., Carychao, D.K., Cooley, M.B., Elhadidy, M. 2020. Panoramic MLVA fingerprinting of Brucella melitensis circulating among livestock and cases of sporadic human illness in Egypt. Transboundary and Emerging Diseases. 1:1-11. https://doi.org/10.1111/tbed.13581.
DOI: https://doi.org/10.1111/tbed.13581

Interpretive Summary: Brucella melitensis is a bacteria pathogen, primarily of domestic animals, but also serious public health threat in humans. The present study investigated the genetic diversity, epidemiological links, and transmission routes of this bacterium in Egypt. From 118 bacterial isolates, 70 genetic types were discovered using a technique called multilocus variable number tandem-repeat analysis. A comparison of genetic types from humans and livestock revealed that the bacteria isolated from humans are closely related to the pathogen from cattle. Also, these pathogens from Egypt and closely related to other Brucella melitensis isolated Europe and other western Mediterranean countries. This information will help to adopt effective prevention, control and eradication strategies for this pathogen in Egypt and other developing nations.

Technical Abstract: Brucella melitensis is a serious public health threat, with human infection causing acute febrile illness and chronic health problems. The present study investigated the genetic diversity, epidemiological links, and transmission routes of the important zoonotic bacterium B. melitensis in Egypt using multilocus variable number tandem-repeat analysis (MLVA-16) including eight minisatellite (panel 1) and eight microsatellite (panel 2, subdivided into 2A and 2B) markers. A total of 118 isolates were identified as B. melitensis biovar 3 by classical biotyping and Bruce-ladder assay. Although B. melitensis is primarily associated with infection in sheep and goats, most of B. melitensis isolates in this study were obtained from secondary hosts (cattle, buffaloes, humans and a camel) suggesting cross-species adaptation of B. melitensis to large ruminants in Egypt. Using MLVA-8 (panel 1), only three genotypes were identified. MLVA-11 (panel 2A) showed the presence of eight genotypes, with genotype 3-5-3-13-1-1-3-3-7-43-8 representing the most common among tested isolates. The MLVA-16 scheme competently discriminated 70 genotypes, with 51 genotypes represented by single isolates and the remaining 19 genotypes were shared among 67 isolates, suggesting both sporadic and epidemiologically related characteristics of B. melitensis infection. Surprisingly, a comparison of MLVA-16 genotypes circulating from human illness and livestock revealed that human brucellosis in Egypt is more related to cattle than to the ovicaprine infection by sharing similar genotype profiles. Matching of local genotypes with representatives of global genotypes revealed that the majority of Egyptian isolates analyzed had a West Mediterranean descendance. As this study represents the first comprehensive genotyping and genetic analysis of B. melitensis from different sources in Egypt, the information generated from this study will augment knowledge of the main transmission routes associated with this bacterium and allow a better understanding of the current epidemiological situation of brucellosis in Egypt. Ultimately, this will help to adopt effective brucellosis prevention, control and eradication strategies in Egypt and other developing nations.