The survival of multi-drug resistant bacteria on raw Douglas fir material.

In today's age of ecological transition, the use of materials such as renewable wood in construction is particularly relevant, but also a challenge in the healthcare sector where the hygiene dimension also comes into play. In this study we have investigated the survival of multi-resistant bacteria commonly responsible for healthcare-associated infections (HAIs) (ESBL-positive Klebsiella pneumoniae and glycopeptide-resistant Enterococcus faecalis) on two different types of wood (Douglas fir : Pseudotsuga menziesii and Maritime Pine : Pinus pinaster) compared to other materials (smooth: stainless steel and rough: pumice stone) and the effect of a disinfection protocol on the bacterial survival on Pseudotsuga menziesii. Approximately 108 bacteria were inoculated on each material and bacterial survival was observed over several days (D0, D1, D2, D3, D6, D7 and D15). Each analysis was performed in triplicate for each time and material. The results show an important reduction of the bacterial inoculum for Klebsiella pneumoniae and Enterococcus faecalis on Douglas fir, in contrast with the results obtained on maritime pine, stainless steel and pumice stone. No bacterial survival was detected on Douglas fir after application of a hospital disinfection protocol. These different results show that wood may have a place in the future of healthcare construction. Further studies would be interesting to better understand the different properties of wood.

Synthetic peptide issued from Hap1/LipL32 for new early serodiagnosis of human leptospirosis.

Leptospirosis is a worldwide zoonosis. Today, serological diagnosis is generally assessed by MAT. We performed ELISA with a synthetic peptide derived from Hap1/lipL32 which is a protein expressed only by pathogenic Leptospira. Repeatability and thresholds were defined with 85 controls sera and 119 hospitalized leptospirosis. The PP-ELISA repeatability and IgM/IgG cut-off values were based on control sera. For these cut-off values, we observed the IgM-PP-ELISA specificity of 89%, whereas it was 100% for the IgG. Then, we compared PP-ELISA and standard MAT results for leptospirosis patients. The concordance rate for IgM-PP-ELISA and MAT was low (43%), whereas it was 85% for IgG-PP-ELISA and MAT. During the first 5 days after hospitalization, PP-ELISA gave positive results in 13 out of 16 patients (81%) whereas 8 out of 14 patients (57%) were positive to MAT. ELISA using Hap1/lipL 32-derived synthetic peptide PP is an earlier serological diagnosis of human leptospirosis than MAT.

Leptospira exposure in the human environment in France: A survey in feral rodents and in fresh water.

This paper confirms the important role of rodents to be maintenance hosts of leptospires. Their role is related to renal carriage and shedding of leptospires into urine, thus contaminating fresh water. Serological and carriage of feral rodents trapped in France were determined by MAT and hap1PCR specific for pathogenic leptospires. In same areas, fresh water samples were analyzed by hap1PCR. The overall seroprevalence was 44% in 649 rodents and was similar regardless of the species. Seroprevalence for leptospirosis is about 20-53% according to species. hap1PCR (516 kidneys) showed that renal carriage was higher in brown rats (34.7%) and muskrats (15.8%) than in coypus (3.3%). hap1PCR demonstrates a significative difference (P-value > 10(-12)) for the renal carriage between the different species: muskrats and rats are more efficient maintenance hosts than coypu but all infect water. Moreover 5/38 water samples associated with human cases were hap1PCR positive and 1/113 in controlled waters.

Protection against Leptospira interrogans sensu lato challenge by DNA immunization with the gene encoding hemolysin-associated protein 1.

The use of DNA constructs encoding leptospiral proteins is a promising new approach for vaccination against leptospirosis. In previous work we determined that immunization with hemolysis-associated protein 1 (Hap1) (LipL32) expressed by adenovirus induced significant protection against a virulent Leptospira challenge in gerbils. To avoid the use of the adenovirus vector, we checked for clinical protection against lethal challenge by DNA vaccination. A DNA vaccine expressing Hap1 was designed to enhance the direct gene transfer of this protein into gerbils. A challenge was performed 3 weeks after the last immunization with a virulent strain of serovar canicola. Our results show that the cross-protective effect with pathogenic strains of Leptospira, shared by Hap1, could be mediated by the DNA plasmid vector. This finding should facilitate the design and development of a new generation of vaccines against bacteria, particularly Leptospira interrogans sensu lato.