Use of molecular subtyping in surveillance for Salmonella enterica serotype typhimurium.

BACKGROUND: Because Salmonella enterica serotype typhimurium is the most common serotype isolated from persons with salmonellosis in the United States, it is difficult to detect unusual clusters or outbreaks. To determine whether molecular subtyping could be useful in public health surveillance for S. enterica serotype typhimurium, the Minnesota Department of Health initiated the routine use of pulsed-field gel electrophoresis (PFGE) of isolates. METHODS: Beginning in 1994, all S. enterica serotype typhimurium isolates submitted by clinical laboratories to the Department of Health were subtyped by PFGE. A standard questionnaire was used to interview patients about possible sources of infection. RESULTS: From 1994 through 1998, 998 cases of infection with S. enterica serotype typhimurium were reported to the Minnesota Department of Health (4.4 cases per 100,000 person-years). PFGE was performed on 958 of the isolates (96 percent), and 174 different patterns were identified. Sixteen outbreaks with a common source were identified, accounting for 154 cases. PFGE subtyping made it possible to confirm 10 outbreaks that involved small numbers of cases in institutional settings. Of six larger, community-based outbreaks, four would probably not have been recognized without PFGE subtyping. These four outbreaks accounted for 96 of the 154 culture-confirmed outbreak cases (62 percent). Fifty-six of 209 isolates tested for antimicrobial susceptibility (27 percent) were resistant to at least five antimicrobial agents. The multidrug-resistant isolates identified had unique PFGE patterns. CONCLUSIONS: Routine molecular subtyping of S. enterica serotype typhimurium by PFGE can improve the detection of outbreaks and aid in the identification of multidrug-resistant strains. Combining routine molecular subtyping with a method of rapid communication among public health authorities can improve surveillance for S. enterica serotype typhimurium infections.

Active, multisite, laboratory-based surveillance for Cryptosporidium parvum.

Cryptosporidium parvum leaped to the attention of the United States following the 1993 outbreak in Milwaukee, Wisconsin, which sickened 400,000 people. Other outbreaks in the United States have been associated with drinking and recreational water, consumption of contaminated foods, contact with animals, and childcare attendance. Despite its public health importance, the number of people who become infected each year is not known. In 1997, active surveillance for C. parvum was added to the Foodborne Diseases Active Surveillance Network (FoodNet), a collaborative effort among the Centers for Disease Control and Prevention, selected state health departments, the U.S. Departments of Agriculture and Food and Drug Administration. During the first 2 years of surveillance, 1,023 laboratory-confirmed cases of cryptosporidiosis were detected in FoodNet (Connecticut, Minnesota, Oregon, and selected counties in California, Georgia, Maryland, and New York). The annual rate per 100,000 persons was 2.3. Sixteen percent of case-patients were hospitalized. A seasonal increase in case detection was noted in late summer among persons less than 15 years of age. These data represent the first active multistate ascertainment of laboratory-confirmed cryptosporidiosis cases and provide useful information on the burden of disease in the United States.

Emergence of domestically acquired ceftriaxone-resistant Salmonella infections associated with AmpC beta-lactamase.

CONTEXT: Ceftriaxone, an expanded-spectrum cephalosporin, is an antimicrobial agent commonly used to treat severe Salmonella infections, especially in children. Ceftriaxone-resistant Salmonella infections have recently been reported in the United States, but the extent of the problem is unknown. OBJECTIVES: To summarize national surveillance data for ceftriaxone-resistant Salmonella infections in the United States and to describe mechanisms of resistance. DESIGN AND SETTING: Case series and laboratory evaluation of human isolates submitted to the Centers for Disease Control and Prevention from 17 state and community health departments participating in the National Antimicrobial Resistance Monitoring System (NARMS) for enteric bacteria between 1996 and 1998. PATIENTS: Patients with ceftriaxone-resistant Salmonella infections between 1996 and 1998 were interviewed and isolates with decreased ceftriaxone susceptibility were further characterized. MAIN OUTCOME MEASURES: Exposures and illness outcomes, mechanisms of resistance. RESULTS: The prevalence of ceftriaxone-resistant Salmonella was 0.1% (1 of 1326) in 1996, 0.4% (5 of 1301) in 1997, and 0.5% (7 of 1466) in 1998. Ten (77%) of the 13 patients with ceftriaxone-resistant infections were aged 18 years or younger. The patients lived in 8 states (California, Colorado, Kansas, Massachusetts, Maryland, Minnesota, New York, and Oregon). Nine (82%) of 11 patients interviewed did not take antimicrobial agents and 10 (91%) did not travel outside the United States before illness onset. Twelve of the 15 Salmonella isolates with ceftriaxone minimum inhibitory concentrations of 16 microg/mL or higher were serotype Typhimurium but these isolates had different pulsed-field gel electrophoresis patterns. Thirteen of these 15 isolates collected between 1996 and 1998 were positive for a 631-base pair polymerase chain reaction product obtained by using primers specific for the ampC gene of Citrobacter freundii. CONCLUSIONS: Domestically acquired ceftriaxone-resistant Salmonella has emerged in the United States. Most ceftriaxone-resistant Salmonella isolates had similar AmpC plasmid-mediated resistance.

Quinolone-resistant Campylobacter jejuni infections in Minnesota, 1992-1998. Investigation Team.

BACKGROUND: Increasing resistance to quinolones among campylobacter isolates from humans has been reported in Europe and Asia, but not in the United States. We evaluated resistance to quinolones among campylobacter isolates from Minnesota residents during the period from 1992 through 1998. METHODS: All 4953 campylobacter isolates from humans received by the Minnesota Department of Health were tested for resistance to nalidixic acid. Resistant isolates and selected sensitive isolates were tested for resistance to ciprofloxacin. We conducted a case-comparison study of patients with ciprofloxacin-resistant Campylobacter jejuni isolated during 1996 and 1997. Domestic chicken was evaluated as a potential source of quinolone-resistant campylobacter. RESULTS: The proportion of quinolone-resistant C. jejuni isolates from humans increased from 1.3 percent in 1992 to 10.2 percent in 1998 (P<0.001). During 1996 and 1997, infection with quinolone-resistant C. jejuni was associated with foreign travel and with the use of a quinolone before the collection of stool specimens. However, quinolone use could account for no more than 15 percent of the cases from 1996 through 1998. The number of quinolone-resistant infections that were acquired domestically also increased during the period from 1996 through 1998. Ciprofloxacin-resistant C. jejuni was isolated from 14 percent of 91 domestic chicken products obtained from retail markets in 1997. Molecular subtyping showed an association between resistant C. jejuni strains from chicken products and domestically acquired infections in Minnesota residents. CONCLUSIONS: The increase in quinolone-resistant C. jejuni infections in Minnesota is largely due to infections acquired during foreign travel. However, the number of quinolone-resistant infections acquired domestically has also increased, largely because of the acquisition of resistant strains from poultry. The use of fluoroquinolones in poultry, which began in the United States in 1995, has created a reservoir of resistant C. jejuni.

Focusing on dreams. A preparation program for psychotherapy.

Forty-eight patients selected as potential early dropouts from insight-oriented psychotherapy were offered a two-week program to prepare them for treatment. Thirty-two were sleep-monitored for eight nights; half were given access to their dreams by awakening them from rapid eye movement (REM) sleep periods; the other half were awakened as often, but only from non-FEM (NREM) stages. A third group of 16 subjects went directly into treatment. All laboratory subjects were asked each morning to recall and discuss the reports they had given during the night. The effect of these discussions was measured on the drop-out rate during the first ten treatment hours and on the development of treatment-appropriate behaviors. Those who successfully retrieved and discussed dreams as opposed to other content stayed in therapy at a significantly higher rate and used the hours more productively.