CTX-M-15 Type Extended-Spectrum Beta-Lactamase-Producing Enterobacter cloacae In Bioaerosol of a Municipal Solid Waste Recycling Plant: A New Possible Reservoir of Infection?

Background: Although there are many reports of antibiotic resistant microorganisms released from the treated municipal wastewater, less attention has been given to other waste treatment activities. We report the occurrence of antibiotic resistant strains isolated from the working setting of a solid waste recycling plant in Italy which serves 195 municipalities. Methods: To assess microbial contamination levels, several sampling points were chosen for their relevance in evaluating exposure of the workers to biological risk, especially during indoor operations. Active sampling was carried out using the Surface Air System and Rodac plate method was applied to surface sampling. Species identification and antimicrobial susceptibilities were obtained by Vitek2 System (bioMérieux, France) and by the agar-diffusion method. The presence of resistance genes was investigated by multiplex PCR assay. Results: In all sampling points a significant contamination of aerosol was detected, although the total microbial counts resulted within the limit proposed by the National authority (10000 CFU/sqm). The counts of Enterobacteriaceae were always above the limit of 100 CFU/sqm and strains of Enterobacter cloacae resistant to third generation cephalosporins were detected, carrying the blaCTX-M15 gene. Conclusions: The contamination of workplace with multidrug-resistant strains is a crucial area for public health actions to avoid the conjunction of factors that promote evolution and spread of antibiotic resistance

Airborne antibiotic resistant bacteria in a solid waste recycling plant: a crucial area for public health actions

Background: The release of antibiotics and any metabolites into the environment by the sewerage system provides the ideal selective and ecological conditions for new resistant strains to arise. Less attention has been given to the spread of resistant bacteria outside of the care centers until now. We report the occurrence of resistence in strains isolated from the working setting of a solid waste recycling plant in Italy. Methods: A solid waste recycling plant was studied to evidence microbial contamination of air and surfaces in working settings. Four sampling points were chosen for their relevance in workers biological risk exposure especially for the operations taking place in indoor environment: the waste reception, the automatic plastic selection, the manual glass selection and the center of the plant. Air samples were collected with an impactor sampler and the Rodac plate method was applied to the surfaces sampling. Identification was carried out by mini-API system and antibiotic susceptibility profiles were determined by the Kirby-Bauer method. Results: Into indoor areas a significant faecal contamination of aerosol was detected. Although the total microbial counts resulted within the limits (10000 CFU/cubic meter) proposed by the Italian Institute INAIL, the coliform bacteria counts were always above the limit of 100 CFU/ cubic meter in all sites and antibiotic resistance was sometimes detected. The contamination by Enterobacteria was confirmed by the identification of Enterobacter cloacae AmpC producer in an aerosol sample collected at the center of the plant, resulted resistant to rifampicin, fosfomycin and broad-spectrum cephalosporins. Pseudomonas aeruginosa resistan to rifampicin and cefoxitin was also detected while doxycycline-resistant, methicillin-susceptible Staphylococcus aureus was isolated from a surface sample collected on the railing of a walkway. Klebsiella pneumoniae resistant to rifampicin was isolated in the aerosol of the automatic plastic selection, where erythromycin-resistant S. aureus was detected on a surface sample. Conclusions: The contamination of workplace with multidrug-resistant strains is a crucial area for public health actions to avoid the conjunction of factors that promote evolution and spread of antibiotic resistance

Vibrational analysis of 1,3-thiazolidine-2-thione and its selenium analogue

The i.r. spectra of 1,3-thiazolidine-2-thione, ?2-selone and their N-deuteriated derivatives have been investigated in the region between 4000 and 20 cm?1. A complete assignment of the fundamental vibrational frequencies has been made based upon the normal coordinate analysis carried out using a simple Urey�Bradley force field supplemented by the valence force constants for the out-of-plane vibrations of the planar molecular skeleton. The proposed assignments are discussed in relation to the group frequencies in structurally related molecules and in terms of the computed potential energy distributions among the symmetry coordinates

CTX-M-15 type Extended-Spectrum Beta-Lactamase-Producing enterobacter cloacae in bioaerosol of a municipal solid waste recycling plant: A new possible reservoir of infection?

Background: Although there are many reports of antibiotic resistant microorganisms released from the treated municipal wastewater, less attention has been given to other waste treatment activities. We report the occurrence of antibiotic resistant strains isolated from the working setting of a solid waste recycling plant in Italy which serves 195 municipalities. Methods: To assess microbial contamination levels, several sampling points were chosen for their relevance in evaluating exposure of the workers to biological risk, especially during indoor operations. Active sampling was carried out using the Surface Air System and Rodac plate method was applied to surface sampling. Species identification and antimicrobial susceptibilities were obtained by Vitek2 System (bioMérieux, France) and by the agar-diffusion method. The presence of resistance genes was investigated by multiplex PCR assay. Results: In all sampling points a significant contamination of aerosol was detected, although the total microbial counts resulted within the limit proposed by the National authority (10000 CFU/sqm). The counts of Enterobacteriaceae were always above the limit of 100 CFU/sqm and strains of Enterobacter cloacae resistant to third generation cephalosporins were detected, carrying the blaCTX-M15 gene. Conclusions: The contamination of workplace with multidrug-resistant strains is a crucial area for public health actions to avoid the conjunction of factors that promote evolution and spread of antibiotic resistance