RESUMO
Listeria monocytogenes is a ubiquitous bacterium that causes a foodborne illness, listeriosis. Most strains can be classified into major clonal complexes (CCs) that account for the majority of outbreaks and sporadic cases in Europe. In addition to the 20 CCs known to account for the majority of human and animal clinical cases, 10 CCs are frequently reported in food production, thereby posing a serious challenge for the agrifood industry. Therefore, there is a need for a rapid and reliable method to identify these 30 major CCs. The high-throughput real-time PCR assay presented here provides accurate identification of these 30 CCs and eight genetic subdivisions within four CCs, splitting each CC into two distinct subpopulations, along with the molecular serogroup of a strain. Based on the BioMark high-throughput real-time PCR system, our assay analyzes 46 strains against 40 real-time PCR arrays in a single experiment. This European study (i) designed the assay from a broad panel of 3,342 L. monocytogenes genomes, (ii) tested its sensitivity and specificity on 597 sequenced strains collected from 24 European countries, and (iii) evaluated its performance in the typing of 526 strains collected during surveillance activities. The assay was then optimized for conventional multiplex real-time PCR for easy implementation in food laboratories. It has already been used for outbreak investigations. It represents a key tool for assisting food laboratories to establish strain relatedness with human clinical strains during outbreak investigations and for helping food business operators by improving their microbiological management plans. IMPORTANCE Multilocus sequence typing (MLST) is the reference method for Listeria monocytogenes typing but is expensive and takes time to perform, from 3 to 5 days for laboratories that outsource sequencing. Thirty major MLST clonal complexes (CCs) are circulating in the food chain and are currently identifiable only by sequencing. Therefore, there is a need for a rapid and reliable method to identify these CCs. The method presented here enables the rapid identification, by real-time PCR, of 30 CCs and eight genetic subdivisions within four CCs, splitting each CC into two distinct subpopulations. The assay was then optimized on different conventional multiplex real-time PCR systems for easy implementation in food laboratories. The two assays will be used for frontline identification of L. monocytogenes isolates prior to whole-genome sequencing. Such assays are of great interest for all food industry stakeholders and public agencies for tracking L. monocytogenes food contamination.
Assuntos
Listeria monocytogenes , Listeriose , Animais , Humanos , Listeria monocytogenes/genética , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase em Tempo Real , Listeriose/diagnóstico , Listeriose/epidemiologia , Listeriose/microbiologia , Europa (Continente)/epidemiologia , Microbiologia de AlimentosRESUMO
Babesia microti and Anaplasma phagocytophilum was recently reported with a minimum prevalence of 0.9 and 1.3% in Hungary based on the PCR-sequencing analysis of 452 European sheep ticks (Ixodes ricinus). These results and the epidemiological data of the neighbouring countries indicate that human cases caused by these pathogens may occur in the country. The aim of the present paper is to summarise the current knowledge on the morphology, life cycle and distribution of B. microti and A. phagocytophilum, and the epidemiology, clinical features, diagnosis, treatment and control of babesiosis and granulocytic anaplasmosis.
Assuntos
Anaplasma phagocytophilum/isolamento & purificação , Anaplasmose , Babesia microti/isolamento & purificação , Babesiose , Ehrlichiose , Zoonoses/epidemiologia , Anaplasma phagocytophilum/genética , Anaplasmose/diagnóstico , Anaplasmose/tratamento farmacológico , Anaplasmose/epidemiologia , Animais , Vetores Artrópodes , Babesia microti/genética , Babesiose/diagnóstico , Babesiose/tratamento farmacológico , Babesiose/epidemiologia , DNA de Protozoário , Ehrlichiose/diagnóstico , Ehrlichiose/tratamento farmacológico , Ehrlichiose/epidemiologia , Europa (Continente)/epidemiologia , Humanos , Hungria/epidemiologia , Incidência , Reação em Cadeia da Polimerase , Prevalência , Zoonoses/microbiologia , Zoonoses/parasitologia , Zoonoses/transmissãoRESUMO
Rickettsia helvetica belonging to spotted fever group rickettsiae was recently detected by polymerase chain reaction followed by sequencing in European sheep ticks (Ixodes ricinus) from Hungary. Current knowledge on these rickettsiae and the clinical and diagnostic aspects of R. helvetica infection is summarized. In acute cases, R. helvetica is generally responsible for flu-like symptoms. Nevertheless, recent data indicate that in chronic cases, these rickettsiae can be responsible for perimyocarditis resulting sudden cardiac death and might play a role in the pathogenesis of aortic valve disease. The diagnosis can be based on serological, molecular and histological methods. A summary of the information available from Hungary and neighbouring countries on the prevalence of tick-borne encephalitis virus, Anaplasma, Borrelia, Francisella, Rickettsia and Babesia infections in I. ricinus is also presented.