Prevalence of Multidrug-resistant Bacteria Rising

The prevalence of Salmonella bacteria resistant to many antibiotics, including expanded-spectrum cephalosporins, rose fivefold between 1998 and 2001, according to a report in the December 1, 2003 issue of The Journal of Infectious Diseases.

The prevalence of Salmonella bacteria resistant to many antibiotics, including expanded-spectrum cephalosporins, rose fivefold between 1998 and 2001, according to a report in the December 1, 2003 issue of The Journal of Infectious Diseases. Infection with Salmonella bacteria resistant to antibiotics increases the rates of illness, hospitalization, and death, the authors explain. In 2000, there was a surge in the rates of the “Newport” strains of Salmonella, especially one called the “Newport-MDRAmpC.” These bacterial strains are resistant to many antibiotics, including amoxicillin/clavulanic acid, cephalothin, cefoxitin, and ceftiofur and have a lower response to ceftriaxone. Dr. Amita Gupta from Centers for Disease Control and Prevention (CDC), Atlanta, and colleagues conducted a field investigation in the New England states that identified the emergence and patterns of infection with new strains of Newport-MDRAmpC. The prevalence of Newport-MDRAmpC among Salmonella Newport bacteria isolated from humans living in Massachusetts increased from 0 percent in 1998 to 53 percent in 2001, the authors report. Among all Newport-MDRAmpC isolates nationally, the prevalence of ceftriaxone resistance increased from 0.5 percent to 2.4 percent during the same interval. The researchers determined that infections with Newport-MDRAmpC were acquired in the United States and were more likely to occur among people who have been around a dairy farm. Visiting, working on, or living on a dairy farm increased the risk of infection by multidrug-resistant Salmonella Newport by 12-fold, the researchers note, whereas yogurt consumption reduced the risk by 87 percent. The most common symptoms were diarrhea, abdominal cramps, fever, and vomiting, the report indicates, and about one third of the patients in one study required hospitalization. “Physicians should be alerted to the rapid increase in Salmonella strains that are resistant to expanded-spectrum cephalosporins such as ceftriaxone, an antimicrobial which is commonly used for the…treatment of fever and sepsis in children,” Gupta, currently at Johns Hopkins University, Baltimore, Maryland, told Reuters Health. “A good history of farm animal contact and food animal consumption should be elicited when such infections are identified,” Gupta added. (Source: The Journal of Infectious Diseases, Reuters Health, Dec 2003.