Genotype diversity of brucellosis agents isolated from humans and animals in Greece based on whole-genome sequencing.

BACKGROUND: Brucellosis is a zoonotic disease whose causative agent, Brucella spp., is endemic in many countries of the Mediterranean basin, including Greece. Although the occurrence of brucellosis must be reported to the authorities, it is believed that the disease is under-reported in Greece, and knowledge about the genomic diversity of brucellae is lacking. METHODS: Thus, 44 Brucella isolates, primarily B. melitensis, collected between 1999 and 2009 from humans and small ruminants in Greece were subjected to whole genome sequencing using short-read technology. The raw reads and assembled genomes were used for in silico genotyping based on single nucleotide substitutions and alleles. Further, specific genomic regions encoding putative virulence genes were screened for characteristic nucleotide changes, which arose in different genotype lineages. RESULTS: In silico genotyping revealed that the isolates belonged to three of the known sublineages of the East Mediterranean genotype. In addition, a novel subgenotype was identified that was basal to the other East Mediterranean sublineages, comprising two Greek strains. The majority of the isolates can be assumed to be of endemic origin, as they were clustered with strains from the Western Balkans or Turkey, whereas one strain of human origin could be associated with travel to another endemic region, e.g. Portugal. Further, nucleotide substitutions in the housekeeping gene rpoB and virulence-associated genes were detected, which were characteristic of the different subgenotypes. One of the isolates originating from an aborted bovine foetus was identified as B. abortus vaccine strain RB51. CONCLUSION: The results demonstrate the existence of several distinct persistent Brucella sp. foci in Greece. To detect these and for tracing infection chains, extensive sampling initiatives are required.

Genotyping of Brucella isolates from animals and humans by Multiple-Locus Variable-number Tandem Repeat Analysis (MLVA).

This study investigates country-wide genotype variations through the genotyping of Brucella strains isolated from domestic ruminants and humans. The Brucella spp. isolated from samples taken from animals and humans were first identified as B. abortus and B. melitensis by real-time PCR, and the MLVA-16 approach was then used for the genotyping of the identified isolates. For the study, 416 Brucella spp. were isolated from aborted fetus samples examined between 2018 and 2021, and 74 Brucella spp. from infected humans. Of the 74 human isolates analyzed, 1.3% were identified as B. abortus and 98.7% (73/74) as B. melitensis. The MLVA-16 typing method revealed 30 clonal groups for B. abortus and 37 clonal groups for B. melitensis from which the dominant genotypes and similarities with human isolates in Türkiye were determined.

Spatio-Temporal Distribution of Brucellosis in European Terrestrial and Marine Wildlife Species and Its Regional Implications.

Brucellosis is an important bacterial zoonosis of domestic and wildlife species. This disease has a significant public health concern and is characterized by reproductive failure resulting in economic losses in the livestock industry. Among thirteen known species, B. abortus, B. melitensis, B. suis, and B. canis are human pathogens. Brucellosis has been extensively investigated in humans and domestic animals. However, the situation in wildlife is still not completely reported and studied. Therefore, a systematic literature search and screening were done to clarify the situation of brucellosis in wildlife in Europe. Sixty-five articles from a total of 13,424 reports published between 1991 and 2021 were selected, applying defined inclusion criteria. Wild boars and brown hares were the most often studied terrestrial wildlife species, whereas seals and porpoises were the most often investigated marine wildlife. Poland, Croatia, and Belgium showed the highest seroprevalences of wild boars caused by B. suis biovar 2. In marine wildlife, brucellosis was mainly caused by B. ceti and B. pinnipedialis. Most samples were from carcasses. Thus, sera could not be collected. It is worrisome that B.abortus and B. melitensis were reported from both terrestrial and marine wild animals, posing a zoonotic threat to people exposed to wild animals. Currently, there is no approved vaccine available for wild animals. The main challenges are the development of specific diagnostics and their validation for use in wildlife.

Evaluation of the genetic profiles of Brucella melitensis strain from Turkey using multilocus variable number tandem repeat analysis (MLVA) and multilocus sequence typing (MLST) techniques.

Brucellosis is caused by Brucella, and Brucella melitensis is highly prevalent in small ruminants in Turkey. Our aim was to genotype 50 B. melitensis strains isolated from sheep, goat, and cattle abortion samples from different farms in seven geographical regions of Turkey between 2009 and 2017. Forty-six different genotypes were detected in 50 isolates studied according to the MLVA-16. Thirty out of 50 isolate profiles matched profiles from the database exactly, and the remaining 20 were absent. Of these 30 isolates, 93.3% were identical to human isolates previously present in the database. All B. melitensis strains belonged to the eastern Mediterranean group. Genotype 43 was the most common isolate profile, and sequence typing (ST8) was dominant and detected in 39 strains. MLST analysis revealed a novel profile in 11 strains. On comparing the sequences of ST8 and the novel ST, a glucokinase gene variation was detected. In the MLST and MLVA analyses, no distinction was made between B. melitensis biovars. Moreover, there was no significant difference between the strains based on host, region, and year. Consequently, the discrimination power of MLVA was higher than that of MLST in this study. Contrastingly, MLST was useful in distinguishing strains according to geographic origins, as determined by performer studies. Profiles determined by MLVA were the same as those in humans. This raises concerns in regard to One Health and transition between hosts, as it is clear that protecting animal health is very important for human health.

Seroprevalence of Q Fever in Sheep and Goats from the Marmara Region, Turkey.

INTRODUCTION: The aim of this study was to investigate Q fever seroprevalence in sheep and goats in the Marmara region. Q fever is a zoonotic disease caused by Coxiella burnetii. In ruminants, the disease causes reproductive disorders, premature births and stillbirths. MATERIAL AND METHODS: Blood samples of sheep and goats were collected from the Marmara region of Turkey and a commercial ELISA was used for detection of specific antibodies to C. burnetii. A total of 832 samples (627 from sheep and 205 from goats) obtained from 126 herds located in 110 villages in 63 municipalities across all 11 provinces were utilised. RESULTS: Total seroprevalence was found to be 13.22%, while the proportion of seropositive herds was determined to be over threefold higher at 42.85%. The seroprevalence for sheep was found to be 14.19%, and for goats 10.24%. The herd seropositivity rate for sheep of 46.31% and for goats of 32.25% were also over threefold higher than the species-level seroprevalences. The provincial seroprevalence varied between 1.38% and 21.79%. CONCLUSION: This study confirms the presence of C. burnetii in sheep and goat herds in the Marmara region and provides original seroprevalence data in hitherto uninvestigated provinces. The data gathered are beneficial for evaluation and elaboration of the seroprevalence of Q fever in sheep and goats in the Marmara region. Surveillance studies should be maintained, particularly in provinces with high seropositivity rates.