Campylobacter continues to be the most commonly reported bacterial enteric pathogen in Minnesota (Figure 1). There were 953 cases of culture-confirmed Campylobacter infection reported in 2001 (19.4 per 100,000 population). This represents a 12% decrease from the 1,079 cases reported in 2000, and a 6% decrease from the mean annual number of cases reported from 1997 to 2000 (mean, 1,043 cases; range, 786 to 1,181). Campylobacter rates were significantly higher in the Southeastern and Southwestern districts of Minnesota than the state rate overall (25.6 and 37.4 cases per 100,000 population, respectively). The Northwestern district had the lowest rate (5.9 cases per 100,000 population). Forty-nine percent of cases occurred in the seven-county Twin Cities metropolitan area. C. jejuni comprised 91% of the isolates confirmed by MDH, and C. coli comprised 8%.
Forty-nine percent of case-patients were 20 to 49 years of age, and 15% were 5 years of age or younger. Fifty-six percent of case-patients were male. Fourteen percent of cases were hospitalized; the median length of hospitalization was 2 days. Forty-six percent of infections occurred during June through September. In March 2001, a food-borne outbreak of C. jejuni was identified; the source of the outbreak was unpasteurized milk served to guests on a farm. Four culture-confirmed cases were 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% to 17%. In 2001, the proportion of quinolone-resistant Campylobacter isolates was 14%. During 2001, approximately 50% of C. jejuni isolates from patients with histories 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. This increase likely is due largely to the use of fluoroquinolones in poultry (the primary source of Campylobacter for humans) in the U.S., which began late in 1995.