The domestic pig is an important source of human salmonellosis, and houseflies are potential mechanical vectors of foodborne Salmonella pathogens. In 2005, we recovered 144 Salmonella isolates from flies and swine stool samples from 11 farms in Taoyuan County and Hsin Chu County (northwestern Taiwan). A total of 71.5% of the isolates were resistant to at least three antibiotics. There were a total of 14 serotypes, and 8 of these serotypes were present in both flies and swine stool samples. Some multidrug-resistant Salmonella strains coming from different swine farms were found to have identical pulsed-field gel electrophoresis (PFGE). Among four common serotypes, we identified 18 PFGE patterns, 8 of which were present in flies and swine stools. The similarity in PFGE profiles between isolates from swine and flies in different farms indicate the potential of flies to serve as a vector for transmission.

The Salmonella typhimurium fimA gene is controlled by several ancillary fim genes. One of these genes, fimZ, appears to be involved in increasing the expression of fimA. A fimZ mutant of S. typhimurium was constructed by allelic exchange, and this mutant was found to be nonfimbriate. The fimZ mutant demonstrated decreased levels of fimA expression compared with the parental strain when both were grown under conditions favoring fimbrial expression. An examination of the predicted amino acid sequence, deduced from the nucleotide sequence of fimZ, indicated that the FimZ polypeptide possessed a DNA binding motif. Bacterial lysates, derived from strains transformed with recombinant plasmids possessing a fimZ gene, demonstrated DNA binding activity with a fragment containing the fimA promoter. Lysates without a FimZ polypeptide did not exhibit any binding activity. These data are consistent with FimZ being a transcriptional activator of fimA, and FimZ acts by binding to the promoter region.

Staphylococcus aureus is a cause of many diseases in both humans and animals. This pathogen is also a major target in the screening of slaughterhouse carcasses to monitor hygienic conditions during...

Coumarin derivatives are used as fluorescent dyes and medicines. They also have some notable physiological effects, including the acute hepatoxicity and carcinogenicity of certain aflatoxins, the anticoagulant action of dicoumarol, and the antibiotic activity of novobicin and coumerymycin A1. Because the number of drug resistant strains is increasing at present, the synthesis of new antibacterial compounds is one of the critical methods for treating infectious diseases. Therefore, a series of coumarin-substituted derivatives, namely 4-hydroxy- and 7-hydroxycoumarins, and 3-carboxycoumarins were synthesized. 4-Hydroxycoumarin derivatives 4a–c underwent rearrangement reactions. Both 4- and 7-hydroxycoumarins were treated with activated aziridines which produced series of ring-opened products 7, 8, 10, and 11. 3-Carboxy-coumarin amide dimer derivatives 14–21 were prepared by reacting aliphatic alkylamines and alkyldiamines with PyBOP and DIEA. In this study, we use a new technique called modified micro-plate antibiotic susceptibility test method (MMAST), which is more convenient, more efficient, and more accurate than previous methods and only a small amount of the sample is required for the test. Some of the compounds were produced by reactions with acid anhydrides and demonstrated the ability to inhibit Gram-positive microorganisms. The dimer derivatives displayed lower antibacterial activities.