Coxiella burnetii em queijos artesanais feitos de leite cru de quatro regiões tradicionais de Minas Gerais e uma do Piauí

Abstract

Q fever is a zoonotic disease with worldwide distribution, caused by Coxiella burnetii, which infects several vertebrate and invertebrate animals, including humans, with domestic ruminants considered its main natural reservoirs. Human infection occurs mainly aerogenously and through ingestion of raw milk, which is a less common but not negligible route. During the period from October 2017 to April 2018, a randomized survey was carried out to evaluate: i) the frequency of C. burnetii DNA in raw milk artisanal cheese (RMAC) from four traditional regions of the state of Minas Gerais Gerais, which produces Minas artisanal cheese (MAC) and the region of Parnaíba, state of Piauí, which produces artisanal coalho cheese; ii) factors associated with C. burnetii positive-RMAC; iii) the relationships of spatial clusters of C. burnetii positive-RMAC and those of the characteristics of the cheese samples such as ripening time, results of microbiological analyzes for other bacterial agents and livestock concentration; iv) the possible relationships between the clusters of C. burnetii positive-MAC and human exposures to the same agent, as well as the concentration of livestock. A total of 100 RMAC samples were collected from different rural family cheese processing agroindustries and subjected to molecular analysis with DNA extraction using the traditional phenol-chloroform-isoamyl alcohol method, using specific oligonucleotides targeting the C. burnetii IS1111 gene. The partial fragment of the IS1111 gene was detected and sequenced in 25 RMAC samples (25.0%; 95% CI 16.8%-34.6%). There were significant differences in C. burnetii positiveRMAC in the producing microregions (p=0.04): Serro (17.0%), Canastra (20.0%), Triangle Mineiro (40.0%), Cerrado (62.0%) and Piauí (21.05%). There was an inverse relationship between the rate of C. burnetii positive-RMAC and the time of registration with the official surveillance body (Slope = -0.011, p = 0.053), and a direct relationship between these same RMAC positivity rates and the rates of cheeses with ripening time above the median (10 days) (Slope = 0.0042, p = 0.0044). This study shows that contamination of RMAC by C. burnetii can represent a possible risk for the consumer of these products, highlighting the need for good agricultural and manufacturing practices, and quality control systems for RMAC. As a randomized survey, we established baseline data on the frequency of C. burnetii in two types of ready-to-eat Brazilian RMAC, to allow the monitoring of temporal and spatial trends, the establishment of control targets, and future studies on local risk analysis.