Insusceptibility to disinfectants in bacteria from animals, food and humans-is there a link to antimicrobial resistance?

Enterococcus faecalis (n = 834) and Enterococcus faecium (n = 135) from blood and feces of hospitalized humans, from feces of outpatients and livestock and from food were screened for their susceptibility to a quaternary ammonium compound (didecyldimethylammoniumchloride, DDAC) and to 28 antibiotics by micro-/macrodilution. The maximum DDAC-MIC in our field study was 3.5 mg/l, but after adaptation in the laboratory, MIC values of 21.

Diversity of antimicrobial resistance genes and class-1-integrons in phylogenetically related porcine and human Escherichia coli.

Antimicrobial resistant bacteria and resistance genes can be transferred between the microbial flora of humans and animals. To assess the dimension of this risk, we compared the phylogenetic ancestry of human and porcine tetracycline-insusceptible Escherichia coli. Further, we compared the resistance gene profiles (tetA/tetB/tetC/tetD/tetM/sulI/sulII/sulIII/strA-strB/addA) and the prevalence of class-1-integrons in isolates of identical and different phylogroups by endpoint-PCR.

Heavy metals in liquid pig manure in light of bacterial antimicrobial resistance.

Heavy metals are regularly found in liquid pig manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 pig manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.

Sewage sludge and liquid pig manure as possible sources of antibiotic resistant bacteria.

Within the last decades, the environmental spread of antibiotic resistant bacteria has become a topic of concern. In this study, liquid pig manure (n=305) and sewage sludge (n=111) - used as agricultural fertilizers between 2002 and 2005 - were investigated for the presence of Escherichia coli, Enterococcus faecalis and Enterococcus faecium. Bacteria were tested for their resistance against 40 chemotherapeutics including several "reserve drugs".

Resistance to linezolid in a porcine Clostridium perfringens strain carrying a mutation in the rplD gene encoding the ribosomal protein L4.

Coresistance to human reserve antibiotics can be selected by antibiotics used in veterinary medicine. A Clostridium perfringens strain isolated from pig manure was resistant to the reserve drug linezolid and, simultaneously, resistant against florfenicol and erythromycin. We detected a new mutation in a highly conserved region of rplD, encoding protein L4 of the 50S ribosomal subunit.

Tetracycline in liquid manure selects for co-occurrence of the resistance genes tet(M) and tet(L) in Enterococcus faecalis.

Causal relations between antibiotic use and selection of antibiotic resistance have been widely discussed. However, appropriate examinations have been mainly performed on phenotypic level, whereas genetic investigations, as well as researches under realistic conditions, are scarce. Therefore, the present field study aimed to accomplish a particular description of how an antibiotic contaminated environment influences microorganisms on both a phenotypic and a genetic level, using analytical, phenotypical and molecular biological methods.