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Risk factors and Molecular genotyping of Brucella melitensis strains recovered from humans and their owned cattle in Upper Egypt.

ABSTRACT: Brucellosis is a zoonosis that has a devastating impact on the economy and public health, particularly in the Middle East, including Egypt. This study aimed to define risk factors associated with brucellosis in humans and in their cattle in Fayoum governorate - Upper Egypt. Also, molecular genotyping of recovered Brucella isolates from human cases and their cattle to assess the potential cross-species transmission in the study region. Data were obtained via double matched case-control studies for brucellosis in humans (106 cases and 160 controls) and in their cattle (78 cattle cases and 105 cattle controls). The results of multivariate regression analysis revealed that predictors of human brucellosis were animal-related occupations (OR 2.1, P 0.02), previous infection in other household members (OR 3.2, P 0.007), eating home-made soft cheese (OR 2.3, P 0.03), and exposure to cattle abortions (OR 6.9, P < 0.001). For cattle, predictors of brucellosis were maturity ≥2 years of age (OR 2.9, P 0.01), ≥2 animals reared by the same household (OR 3.7-6.9, P ≤ 0.001), and recent abortion (OR 15.2, P 0.01). Twelve Brucella isolates were recovered from eight human cases (7.5%, 8/106) and four cattle cases (6.2%, 4/65). All isolates were B. melitensis biovar 3. Analysis of the IS711 gene sequence revealed complete homology (100%) between isolates. Six virulence genes were utilized for virutyping: virB (100%), omp25 (100%), amiC (100%), ure (91.7%), wbkA (91.7%), and bvfA (75%). Virutyping revealed four virutypes: V1 (lack bvfA, 16.7%), V2 (harbored all genes, 66.7%), V3 (lack wbkA, 8.3%), and V4 (lack wbkA and ure, 8.3%). Repetitive extragenic palindromic PCR (REP-PCR) typing revealed two REP types. Combined REP-PCR/virulence genotyping revealed five different genotypes (G1-G5) for the detected isolates and a unique genotype for the reference strain (G6, B. melitensis bv3 Ether). Human and cattle isolates from the same household had matched genotypes. In conclusion, there were widespread risk factors among the cases studied. Health education for high-risk groups is essential for disease prevention, and combined REP-PCR/virulence genotyping is a quick tool for traceability, particularly in developing countries endemic with brucellosis as Egypt.

SUBMITTER: Abdel-Hamid NH

PROVIDER: S-EPMC8246634 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Brucella melitensis primarily affects sheep, goats and is associated with brucellosis in humans, which is one of the world's most widespread neglected zoonotic disease. The current study attempted the determination of genetic diversity through comparative genome analysis of B. melitensis strains reported from India with other countries. The study also reports the isolation and identification of B. melitensis BMNDDB8664 from a cow with a history of abortion, whole-genome sequencing (WGS), determination of virulence factors, genotyping, and comparative genome analysis. Multilocus sequence typing, Multiple locus variable number of tandem repeats analysis (MLVA), and WGS based phylogeny revealed the predominance of ST-8 and genotypes (116 and II respectively) that clustered to the East Mediterranean lineage. Identification of hitherto unreported genotypes by MLVA also indicated the existence and circulation of West Mediterranean and American lineages in India. Though the AMOS-PCR results suggest the BMNDDB8664 isolate as Brucella abortus, the outcomes from multiplex PCR, ribosomal multilocus sequence typing, and WGS analysis confirmed it as B. melitensis. The analysis revealed the presence of adeF gene (aids conferring resistance to fluoro-quinolone and tetracyclines). The isolate lacked two important T4SS genes virB2 and virB7 genes (roles in infection and rifampicin resistance respectively) and also lacked the Brucella suis mprF gene that aids intracellular survival. Further, BMNDDB8664 lacked some of the genes associated with LPS synthesis (wbkB, wbkC) and transport (wzm, wzt) and hence, is most likely a rough strain. WGS-based phylogenetic analysis revealed close genetic relatedness of this BMNDDB8664 with a sheep isolate and two human isolates. The results prompt systematic, broad-based epidemiological studies on brucella infection at the species level. For effective control of human brucellosis, a concerted One Health approach with studies encircling the identification of aetiology at species, strain level to find their prevalence, spread, and inter-host transmission patterns need to be understood, for better design and implementation of effective control strategies in India and other endemic regions.Supplementary informationThe online version contains supplementary material available at 10.1007/s12088-023-01081-w.

Project description:BackgroundAzerbaijan currently ranks thirteenth in global incidence of human brucellosis, with an estimated annual incidence through 2000 at over 50 cases per million. Brucella melitensis has been isolated from patients and is thought to have been acquired through contact with small ruminants or as a foodborne infection. To reduce the burden of human brucellosis, the Azerbaijani government began in 2002, a nationwide vaccination control campaign in small ruminants. There is serological evidence of bovine brucellosis (presumably due to Brucella abortus) in Azerbaijan, but no prevalence estimates were available when this study started in March 2017. The aim of this study was to isolate and identify Brucella spp. from cow milk in the Ganja region, where brucellosis takes a heavy toll on humans and livestock.ResultsBlood and milk samples were collected from cows (n = 1075) in early lactation (up to 90-days) in farms that had a history of previous positive serological results and abortions. Twenty-two out of 57 milk samples collected from seropositive cows, showed growth on Farrell's media, when incubated with 5% CO2. Eight additional milk samples showed growth in the absence of CO2. The classical biotyping classified them as Brucella abortus (22) and Brucella melitensis (8). RT-PCR confirmed that strains belonged to the genus Brucella. MLVA profiles were obtained for DNA extracted from two B. abortus and six B. melitensis strains. While the B. abortus genetic profile was described in the MLVA database, matching the profile of B. abortus strains isolated in East Europe, Central Asia and China, we found a new genotype for the B. melitensis strains isolated in Azerbaijan, clustering with strains belonging to the American clade, rarely identified in the region.ConclusionDespite the implementation of the vaccination program in small ruminants, our results suggest that spill-over events of B. melitensis from small ruminants to cattle have occurred. However, cattle are likely to be primarily infected with B. abortus, which warranted the implementation of a bovine brucellosis program. Such a program started in fall 2017. In the Ganja region, cattle should be considered as a potential source of B. abortus and B. melitensis for humans.

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Risk factors and Molecular genotyping of Brucella melitensis strains recovered from humans and their owned cattle in Upper Egypt.

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