Zoonotic Transfer of Clostridium difficile Harboring Antimicrobial Resistance between Farm Animals and Humans

The emergence of Clostridium difficile as a significant human diarrheal pathogen is associated with the production of highly transmissible spores and the acquisition of antimicrobial resistance genes (ARGs) and virulence factors. Unlike the hospital-associated C. difficile RT027 lineage, the community-associated C. difficile RT078 lineage is isolated from both humans and farm animals; however, the geographical population structure and transmission networks remain unknown. Here, we applied whole-genome phylogenetic analysis of 248 C. difficile RT078 strains from 22 countries. Our results demonstrate limited geographical clustering for C. difficile RT078 and extensive coclustering of human and animal strains, thereby revealing a highly linked intercontinental transmission network between humans and animals. Comparative whole-genome analysis reveals indistinguishable accessory genomes between human and animal strains and a variety of antimicrobial resistance genes in the pangenome of C. difficile RT078. Thus, bidirectional spread of C. difficile RT078 between farm animals and humans may represent an unappreciated route disseminating antimicrobial resistance genes between humans and animals. These results highlight the importance of the "One Health" concept to monitor infectious disease emergence and the dissemination of antimicrobial resistance genes.

Portal hypertension in schistosomiasis: a long-term follow-up of a randomized trial comparing three types of surgery

The long-term follow-up of patients with the severe form of Manson's schistosomiasis who had had elective surgical treatment for portal hypertension, in a randomized trial, was clinically evaluated. Of 94 patients, proximal splenorenal shunting was performed in 32, esophagogastric devascularization with splenectomy in 32 and distal splenorenal shunting in 30. Patients were observed during a mean of 85.7 +/- 33.1 mo, excluding nine patients (9.6%) who were lost to follow-up. Recurrence of upper gastrointestinal tract bleeding occurred in 24.1% of the patients, without statistical differences among the three groups, but rebleeding because of varices was more frequent after esophagogastric devascularization with splenectomy. Hepatic encephalopathy was significantly higher after proximal splenorenal shunting (39.3%) when compared with distal splenorenal shunting (14.8%) and with esophagogastric devascularization with splenectomy (0%). Lethality was also significantly higher after proximal splenorenal shunting (42.9%) when compared with distal splenorenal shunting (14.8%) and with esophagogastric devascularization with splenectomy (7.1%). Indirect hyperbilirubinemia was absent after esophagogastric devascularization with splenectomy and more frequent after distal splenorenal shunting (52%) although also present after proximal splenorenal shunting (29.6%). Esophagogastric devascularization with splenectomy was demonstrated to be the best option because of the absence of encephalopathy and because of low mortality rates. Hepatic encephalopathy occurred after distal splenorenal shunting but in a lesser percentage than after proximal splenorenal shunting. The higher incidence of encephalopathy and lethality proscribes proximal splenorenal shunting in Manson'schistosomiasis.

Geochronology of the Carboniferous, Permian and Triassic

Criteria concerning sample and analytical data and stratigraphic control have been used in a critical assessment of the suitability, for use in construction of a Phancrozoic time-scale, of radiometric data relevant to the Carboniferous, Permian and Triassic periods. Few of the age determinations available in 1982 satisfy these criteria and many of those used previously as a basis for time-scales for this part of the Phanerozoic are considred unacceptable by present standards. On the basis of this review, ages of 365 ± 5 Ma, 290 ± Ma and 250 © 5 Ma. respectively, are proposed for the beginning of the Carboniferous. Permain and Triassic periods, and 205 © 5 Ma for the end of the Triassic. Radiometric ages are related. where possible, to the principal chronostratigraphic divisions of the rock successions representing those periods.