Campylobacter continues to be the most commonly reported bacterial enteric pathogen in Minnesota (Figure 2). There were 1,079 cases of culture-confirmed Campylobacter infection reported to MDH in 2000 (22.0 per 100,000 population). This represents a 37% increase from the 786 cases reported in 1999. Of Campylobacter isolates submitted to MDH, 90% were C. jejuni and 7% were C. coli. Fifty-five percent of cases resided in the seven-county Twin Cities metropolitan area. Fifty-one percent of cases were 20 to 49 years of age, and 14% of cases were 5 years of age or younger. Fifty-three percent of infections occurred during June through September. One outbreak of campylobacteriosis was identified in 2000; the source of the outbreak was malts made with unpasteurized milk and served at a dairy farm. There was one culture-confirmed case and seven suspected cases associated with this outbreak.
The primary feature of public health importance among Campylobacter cases was the continued presence of Campylobacter isolates resistant to fluoroquinolone antibiotics (e.g., ciprofloxacin), which commonly are used to treat campylobacteriosis. From 1992 to 1999, the proportion of quinolone-resistant C. jejuni isolates increased from 1.3% to 17.3%. In 2000, the proportion of quinolone-resistant Campylobacter isolates was 11.4%. The proportion of resistant isolates peaked during the winter months of each year; these increases were associated with foreign travel (particularly to Mexico). During 2000, more than 60% of C. jejuni isolates from patients with a history of foreign travel (regardless of destination) during the week before onset of illness were resistant to fluoroquinolones. Domestically acquired quinolone-resistant C. jejuni infections also have increased significantly since 1996. Quinolone-resistant C. jejuni isolates were recovered from 14% of retail chicken products acquired by MDH in the seven-county metropolitan area in 1997; identical molecular subtypes were found among resistant isolates from chicken products and resistant isolates from domestically acquired human infections. Thus, the increase in domestically acquired resistant cases among humans likely is due largely to the use of fluoroquinolones in poultry in the United States, which began late in 1995.