Canine brucellosis in Costa Rica reveals widespread Brucella canis infection and the recent introduction of foreign strains.

Brucellosis is a prevalent disease in Costa Rica (CR), with an increasing number of human infections. Close to half of homes in CR have one or more dogs, corresponding to ∼1.4 million canines, most of them in the Central Valley within or near the cities of San José, Heredia, and Alajuela. From 302 dog sera collected from this region, 19 were positive for Brucella canis antigens, and five had antibodies against smooth lipopolysaccharide, suggesting infections by both B. canis and other Brucella species. B. canis strains were isolated in the Central Valley from 26 kennel dogs and three pet dogs, all displaying clinical signs of canine brucellosis. We detected three recent introductions of different B. canis strains in kennels: two traced from Mexico and one from Panama. Multiple locus-variable number tandem repeats (MLVA-16) and whole-genome sequencing (WGSA) analyses showed that B. canis CR strains comprise three main lineages. The tree topologies obtained by WGSA and MLVA-16 just partially agreed, indicating that the latter analysis is not suitable for phylogenetic studies. The fatty acid methyl ester analysis resolved five different B. canis groups, showing less resolution power than the MLVA-16 and WGSA. Lactobacillic acid was absent in linages I and II but present in linage III, supporting the recent introductions of B. canis strains from Mexico. B. canis displaying putative functional cyclopropane synthase for the synthesis of lactobacillic acid are phylogenetically intertwined with B. canis with non-functional protein, indicating that mutations have occurred independently in the various lineages.

Pharmaceuticals in farms and surrounding surface water bodies: Hazard and ecotoxicity in a swine production area in Costa Rica.

The presence of pharmaceuticals in the environment is known to have multiple origins; livestock activities comprise one scarcely studied source, both globally and specially in Latin-America. This work aims to study the occurrence of pharmaceuticals in wastewater from swine farms and their surrounding surface waters, in a highland livestock production area of Costa Rica. The monitoring of 70 pharmaceutical active compounds resulted in the detection of 10 molecules in farm wastewater (influents and effluents of the on-farm treatment system), including compounds of animal and human use. A 57% of effluents showed high hazard (ΣHQ > 1), mainly due to the compounds risperidone, ketoprofen, ibuprofen and naproxen. Additionally, ecotoxicological tests with Daphnia magna and Microtox classified at least 21% of the effluents as very toxic (10 < TU ≤ 100); likewise, 86% of effluents exhibited germination index (GI) inhibition values over 90% for Lactuca sativa. Seven molecules were detected in surface water, six of them of human use (1,7-dimethylxanthine, caffeine, cephalexin, carbamazepine, gemfibrozil, ibuprofen) and one (acetaminophen) of dual (human and veterinary) use; nonetheless, most of the detections were found in sampling points closer to human settlements than animal farms. Considering the set of molecules and their distribution, the livestock influence on surface water seems minimal in comparison with the urban influence. Only 16% of surface water samples showed high risk, mainly due to ibuprofen, gemfibrozil and caffeine; similarly, 45% samples presented GI inhibition >20% (no toxicity was determined towards Daphnia magna or Microtox). These findings in surface water suggest an incipient environmental risk in the area.

Expanding the application scope of on-farm biopurification systems: Effect and removal of oxytetracycline in a biomixture.

Antibiotic-containing wastewaters produced in agricultural activities may depress the pesticide-degrading capacity of biomixtures contained in biopurification systems. This work aimed to assay the effect of oxytetracycline (OTC) on the removal of carbofuran (CFN) in an optimized biomixture, and to determine the capacity of the system to dissipate OTC. During co-application of CFN+OTC, CFN removal and its accelerated degradation were not negatively affected. Similarly, different doses of OTC (10-500mgkg-1) did not significantly affect CFN mineralization, and the process even exhibited a hormetic-like effect. Moreover, the biomixture was able to remove OTC with a half-life of 34.0 d. DGGE-cluster analyses indicated that fungal and bacterial communities remained relatively stable during OTC application and CFN+OTC co-application, with similarities of over 70% (bacteria) and 80% (fungi). Overall, these findings support the potential use of this matrix to discard OTC-containing wastewater in this system originally intended for CFN removal.