Seroprevalence and Molecular Identification of Brucella spp. in Camels in Egypt

Khan, Aman Ullah; Sayour, Ashraf E.; Melzer, Falk; El-Soally, Sherif Abdel Ghafar Elsayed; Elschner, Mandy C.; Shell, Waleed S.; Moawad, Amira A.; Mohamed, Shereen Aziz; Hendam, Ashraf; Roesler, Uwe; Neubauer, Heinrich; El-Adawy, Hosny

doi:10.3390/microorganisms8071035

Cited by 25 publications

(31 citation statements)

References 44 publications

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“…Isolation of B. suis , B. melitensis, and B. abortus from livestock has been reported recently [ 8 , 9 ]. Brucella abortus and B. melitensis have also been isolated from humans, but B. suis has thus far only been identified in cattle, pigs, and camels [ 10 , 11 , 12 , 13 ]. Like in many other countries of the Mediterranean Basin, B. melitensis is the predominant Brucella spp.…”

Section: Introductionmentioning

confidence: 99%

Whole-Genome Sequencing for Tracing the Genetic Diversity of Brucella abortus and Brucella melitensis Isolated from Livestock in Egypt

et al. 2021

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Brucellosis is a highly contagious zoonosis that occurs worldwide. Whole-genome sequencing (WGS) has become a widely accepted molecular typing method for outbreak tracing and genomic epidemiology of brucellosis. Twenty-nine Brucella spp. (eight B. abortus biovar 1 and 21 B. melitensis biovar 3) were isolated from lymph nodes, milk, and fetal abomasal contents of infected cattle, buffaloes, sheep, and goats originating from nine districts in Egypt. The isolates were identified by microbiological methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Differentiation and genotyping were confirmed using multiplex PCR. Illumina MiSeq® was used to sequence the 29 Brucella isolates. Using MLST typing, ST11 and ST1 were identified among B. melitensis and B. abortus, respectively. Brucella abortus and B. melitensis isolates were divided into two main clusters (clusters 1 and 2) containing two and nine distinct genotypes by core-genome SNP analysis, respectively. The genotypes were irregularly distributed over time and space in the study area. Both Egyptian B. abortus and B. melitensis isolates proved to be genomically unique upon comparison with publicly available sequencing from strains of neighboring Mediterranean, African, and Asian countries. The antimicrobial resistance mechanism caused by mutations in rpoB, gyrA, and gyrB genes associated with rifampicin and ciprofloxacin resistance were identified. To the best of our knowledge, this is the first study investigating the epidemiology of Brucella isolates from livestock belonging to different localities in Egypt based on whole genome analysis.

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Section: Introductionmentioning

confidence: 99%

Whole-Genome Sequencing for Tracing the Genetic Diversity of Brucella abortus and Brucella melitensis Isolated from Livestock in Egypt

et al. 2021

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“…Validation is the process that determines the fitness of a developed, standardized, and optimized assay used for the aim of diagnosis. Conventional PCR and RT-PCR have been used as a diagnostic tool in most of the published research for the detection of DNA of Brucella species in serum samples of small ruminants [19], camels [20,21], bovine [22][23][24], swine [25], and humans [26,27] without first being validated or validated in an accurate manner. Some authors have previously considered serum as the sample of choice for the same purpose [28].…”

Section: Resultsmentioning

confidence: 99%

Validation of real-time polymerase chain reaction versus conventional polymerase chain reaction for diagnosis of brucellosis in cattle sera

et al. 2021

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Background and Aim: Different polymerase chain reaction (PCR) techniques have and are still being used for the direct detection of Brucella DNA in serum samples of different animal species and humans without being validated or properly validated, resulting in discrepancies. Thus, this study aimed to evaluate the diagnostic performance of the TaqMan Real- Time-PCR (RT-PCR) targeting the bcsp31 gene versus conventional PCR for the accurate diagnosis of brucellosis at the genus level in cattle sera. Materials and Methods: One hundred and eighty-four serum samples were collected from bacteriologically positive and negative cows with ages ranging from 1 to 5 years old at some infected private farms in the Nile Delta under quarantine measures as well as brucellosis free farms. These samples were classified into four groups after serological diagnosis and investigated by TaqMan RT-PCR and conventional PCR targeting the IS711 gene for Brucella DNA detection. The diagnostic performance characteristics of both PCR techniques were estimated considering the bacteriological results as a gold standard. Results: TaqMan RT-PCR revealed superiority over conventional PCR; it was able to detect Brucella DNA in 95% (67/70) and 89% (25/28) of the cattle sera samples belonging to Group 1 (serologically and bacteriologically positive) and Group 2 (serologically negative but bacteriologically positive), respectively. On evaluating the diagnostic performance, TaqMan RT-PCR showed superior diagnostic sensitivity (93.9%), diagnostic specificity (88.4%), performance index (182.3), almost perfect kappa agreement (0.825±0.042), strong positive correlation (r=0.826), high accuracy based on the receiver operating characteristic (ROC) curve, and area under the ROC curve (0.911) at p<0.05 and CI of 95%. Conclusion: A cattle serum sample is not the metric of choice for targeting Brucella genomic DNA by conventional PCR. The time-saving and rapid TaqMan RT-PCR method revealed a better diagnostic performance in the detection of Brucella DNA in cattle sera. Such performance offered by TaqMan RT-PCR may be considered a step toward the possibility of using such technology in the direct differentiation between Brucella-infected and -vaccinated cattle immunized by smooth vaccines from cattle sera using primers specific for such vaccines.

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“…Based on the c-ELISA results, the individual seroprevalence of camel brucellosis in this study was estimated at 7%; this is the highest seroprevalence of camel brucellosis reported in Somalia. Despite the fact that there is no c-ELISA assay specifically validated in camels, the assay is widely used in the diagnosis of camel brucellosis [ 20 ]. Further, a study by Sayour et al (2015) suggests that c-ELISA is an excellent test for the detection of Brucella antibodies in camels, but needs further standardization in camel sera [ 21 ].…”

Section: Discussionmentioning

confidence: 99%

Seroprevalence and Risk Factors Associated with Brucella Infection in Camels in the Puntland State of Somalia

Mohamud

Kothowa²,

Mfune

et al. 2021

Veterinary Sciences

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Brucellosis is an important zoonotic disease caused by members of the genus Brucella. Camel brucellosis has been reported in almost all camel-rearing countries in Africa and Asia. A cross-sectional study was conducted between February 2020 and February 2021 in Galkayo, Garowe, and Bosaso districts in the Puntland State of Somalia to investigate the seroprevalence and risk factors of brucellosis in camels. A competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect anti-Brucella antibodies, while a structured questionnaire was used to collect epidemiological data. A total of 441 camel sera were screened against Brucella antibodies. Thirty-one (7%; 95% CI: 4.8–9.8%) samples were positive, and thirteen (54.2%; 95% CI: 32.8–74.4%) out of the twenty-four farms sampled had at least one seropositive animal. Galkayo district had the highest number of Brucella-seropositive camels (10.3%), followed by Bosaso district (8.6%), while Garowe district had the lowest number of seropositive camels (1.4%). The binary logistic regression model revealed that camels in Galkayo district (p = 0.015; OR: 9.428; 95% CI: 1.539–57.755), camels from large herd sizes of >50 animals (p = 0.019; OR: 5.822; 95% CI: 1.336–25.371), and those in contact with small ruminants (p = 0.011; OR: 10.941; 95% CI: 1.728–69.285) were significantly associated with seropositive cases of camel brucellosis in the Puntland State of Somalia. The present study shows that Brucella infections in camels are prevalent in the three districts covered by the study. This poses a public health risk, because milk from these camels is used for human consumption. Studies focusing on the isolation of Brucella strains in camels and investigating brucellosis in ruminants and humans are recommended in the study area. Validation of serological tests—including c-ELISA—for Brucella antibody detection in camels is also needed.

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Seroprevalence and Molecular Identification of Brucella spp. in Camels in Egypt

Cited by 25 publications

References 44 publications

Whole-Genome Sequencing for Tracing the Genetic Diversity of Brucella abortus and Brucella melitensis Isolated from Livestock in Egypt

Whole-Genome Sequencing for Tracing the Genetic Diversity of Brucella abortus and Brucella melitensis Isolated from Livestock in Egypt

Validation of real-time polymerase chain reaction versus conventional polymerase chain reaction for diagnosis of brucellosis in cattle sera

Seroprevalence and Risk Factors Associated with Brucella Infection in Camels in the Puntland State of Somalia

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