Is Escherichia coli urinary tract infection a zoonosis? Proof of direct link with production animals and meat.

Recently, it has been suggested that the Escherichia coli causing urinary tract infection (UTI) may come from meat and animals. The purpose was to investigate if a clonal link existed between E. coli from animals, meat and UTI patients. Twenty-two geographically and temporally matched B2 E. coli from UTI patients, community-dwelling humans, broiler chicken meat, pork, and broiler chicken, previously identified to exhibit eight virulence genotypes by microarray-detection of approximately 300 genes, were investigated for clonal relatedness by PFGE. Nine isolates were selected and tested for in vivo virulence in the mouse model of ascending UTI. UTI and community-dwelling human strains were closely clonally related to meat strains. Several human derived strains were also clonally interrelated. All nine isolates regardless of origin were virulent in the UTI model with positive urine, bladder and kidney cultures. Further, isolates with the same gene profile also yielded similar bacterial counts in urine, bladder and kidneys. This study showed a clonal link between E. coli from meat and humans, providing solid evidence that UTI is zoonosis. The close relationship between community-dwelling human and UTI isolates may indicate a point source spread, e.g. through contaminated meat.

Development of a new integrated diagnostic test for identification and characterization of pathogens.

Animal diseases directly cause multi-million dollar losses world-wide. Therefore a rapid, highly specific, cost-effective diagnostic test for detecting a large set of bacterial virulence and antimicrobial resistance genes simultaneously is necessary. Hence, our group, the BCBG (Bacterial Chips Bacterial Genes) group, proposes developing a powerful molecular tool (DNA microarray) to detect a broad range of infectious agents, their endogenous main virulence factors and antibiotic resistance genes simultaneously. Effectively, a 70-mer oligonucleotide microarray capable of detecting the presence or absence of 169 Escherichia coli virulence genes or virulence marker genes as well as their variants, in addition to 30 principal antimicrobial resistance genes previously characterized in E. coli strains was developed by our group. This microarray was validated with a large collection of well characterized pathogenic and reference E. coli strains. Moreover, we are developing a new powerful clinical diagnostic microarray tool, to identify pathogenic bacteria of veterinary interest. The commercialization of this assay would allow same day diagnosis of infectious agents and their antibiotic resistance resulting in early treatment. In addition, this technology is also applicable to microbial quality control of food and water.

Identification of new phages to type Staphylococcus aureus strains and comparison with a genotypic method.

The aim of this study was to optimize the epidemiological monitoring of strains of Staphylococcus aureus, a major cause of hospital-acquired infections. From September to December 1998 47 S. aureus strains isolated from swabs taken from orthopaedic and trauma patients were in studied. Thirty-five isolates were sensitive to methicillin (MSSA) and 12 were methicillin-resistant (MRSA). Ten of the 47 isolates could not be phage-typed using the international set of typing phages: five of these isolates were MSSA and five were MRSA. These MRSA isolates, which were also not typeable by the phages currently recommended for phage-typing MRSA, were lysed by locally isolated experimental phages 584 and 1814. Phage 1814 lysed the gentamicin-resistant MRSA and phage 584 acted on the gentamicin-sensitive MRSA. Both new phages were inactive against the methicillin-sensitive isolates. Cloning of certain isolates was confirmed by macrorestriction genomic profiles obtained by pulsed-field gel electrophoresis analysis (PFGE). The results showed good discriminatory ability of antibiotic-resistance pattern phenotyping and phage-typing when the phages used were adapted to epidemic-associated MRSA strains.

Population analysis of mesophilic microbial fuel cells fed with carbon monoxide.

Electricity generation in a microbial fuel cell (MFC) fed with carbon monoxide (CO) has been recently demonstrated; however, the microbial ecology of this system has not yet been described. In this work the diversity of the microbial community present at the anode of CO-fed MFCs was studied by performing denaturing gradient gel electrophoresis (DGGE) and high-throughput sequencing (HTS) analyses. HTS indicated a significant increase of the archaeal genus Methanobacterium and of the bacterial order Clostridiales, notably including Clostridium species, while in both MFCs DGGE identified members of the bacterial genera Geobacter, Desulfovibrio, and Clostridium, and of the archaeal genera Methanobacterium, Methanofollis, and Methanosaeta. In particular, the presence of Geobacter sulfurreducens was identified. Tolerance of G. sulfurreducens to CO was confirmed by growing G. sulfurreducens with acetate under a 100 % CO atmosphere. This observation, along with the identification of acetogens, supports the hypothesis of the two-step process in which CO is converted to acetate by the carboxidotrophic Bacteria and acetate is then oxidized by CO-tolerant electricigenic bacteria to produce electricity.