According to White et al, 20% of 200 meat samples (beef, turkey, pork, and ground chicken) purchased at 3 supermarkets in the greater Washington, DC, area contained Salmonella. Resistance to at least 1 antibiotic was demonstrated in 84% of the isolates, while resistance to at least 3 antibiotics was found in 53% of the isolates (including tetracycline, streptomycin and sulfamethoxazole). Similar DNA patterns were found in isolates from different meat samples obtained in different stores.
In 1999, the combination of quinupristin-dalfopristin was approved to treat vancomycin-resistant Enterococcus faecium infections. In the study by McDonald et al, samples from 207 chickens from 26 stores in 4 states were obtained between July 1998 and June 1999, as well as from 334 human stool samples. Quinupristin-dalfopristin-resistant E faecium was isolated from 237 chickens and 3 stools.
In a randomized, double-blind study conducted by Sorensen et al, 18 healthy volunteers were given 107 CFU of quinupristin-dalfopristin-resistant E faecium obtained from chicken purchased in a store. Eight of 12 subjects had this organism in their stools on day 6, as did 1 of 12 subjects on day 14. All were negative prior to the study and 35 days later suggesting that colonization is possible but perhaps not lasting.
In the study from Manges et al, 22% of 255 Escherichia coli isolates from adult women with an E coli UTI in California were resistant to trimethoprim-sulfamethoxazole. DNA fingerprinting of the resistant isolates identified 51% as belonging to clonal group A. Investigators also determined that 38% and 39% of women living in Michigan and Minnesota, respectively, demonstrated trimethoprim-sulfamethoxazole-resistant E coli with identical DNA characteristics.
In the study by Hyde et al, drug resistance to macrolide antibiotics (erythromycin, azithromycin and clarithromycin) was evaluated by means of minimum inhibitory concentrations (MICs) in 15,841 Streptococcus pneumoniae isolates of which 4,132 were associated with invasive pneumococcal disease. The isolates, which were obtained between 1993 and 1999, came from 7 different states. During this time, the overall use of macrolides increased 13% (320% in children <5 years of age). Between 1995 and 1999 macrolide resistance increased from 10.6% to 20.4%....