Decreased Susceptibility to Azithromycin in Clinical Shigella Isolates Associated with HIV and Sexually Transmitted Bacterial Diseases, Minnesota, USA, 2012-2015.

Shigellosis outbreaks caused by Shigella with decreased susceptibility to azithromycin (DSA-Shigella) among men who have sex with men (MSM) have been reported worldwide. We describe sexual health indicators and antimicrobial drug resistance for shigellosis cases in Minnesota, USA. We analyzed a sample of isolates received during 2012-2015 and cross-referenced cases with the Minnesota Department of Health Sexually Transmitted Disease Database to ascertain patients' HIV status and recent chlamydia, gonorrhea, and syphilis infections. Of 691 Shigella isolates, 46 (7%) were DSA-Shigella; 91% of DSA-Shigella patients were men, of whom 60% were living with HIV. Among men, those with DSA-Shigella infection had greater odds of living with HIV, identifying as MSM, or having a recent diagnosis of a sexually transmitted disease. DSA-Shigella was associated with MSM, HIV infection, and recent sexually transmitted disease. To decrease spread of DSA-Shigella, interventions targeted at communities at high risk are needed.

Multicenter Evaluation of Clinical Diagnostic Methods for Detection and Isolation of Campylobacter spp. from Stool.

The use of culture-independent diagnostic tests (CIDTs), such as stool antigen tests, as standalone tests for the detection of Campylobacter in stool is increasing. We conducted a prospective, multicenter study to evaluate the performance of stool antigen CIDTs compared to culture and PCR for Campylobacter detection. Between July and October 2010, we tested 2,767 stool specimens from patients with gastrointestinal illness with the following methods: four types of Campylobacter selective media, four commercial stool antigen assays, and a commercial PCR assay. Illnesses from which specimens were positive by one or more culture media or at least one CIDT and PCR were designated "cases." A total of 95 specimens (3.4%) met the case definition. The stool antigen CIDTs ranged from 79.6% to 87.6% in sensitivity, 95.9 to 99.5% in specificity, and 41.3 to 84.3% in positive predictive value. Culture alone detected 80/89 (89.9% sensitivity) Campylobacter jejuni/Campylobacter coli-positive cases. Of the 209 noncases that were positive by at least one CIDT, only one (0.48%) was positive by all four stool antigen tests, and 73% were positive by just one stool antigen test. The questionable relevance of unconfirmed positive stool antigen CIDT results was supported by the finding that noncases were less likely than cases to have gastrointestinal symptoms. Thus, while the tests were convenient to use, the sensitivity, specificity, and positive predictive value of Campylobacter stool antigen tests were highly variable. Given the relatively low incidence of Campylobacter disease and the generally poor diagnostic test characteristics, this study calls into question the use of commercially available stool antigen CIDTs as standalone tests for direct detection of Campylobacter in stool.

Notes from the Field: Outbreaks of Shigella sonnei Infection with Decreased Susceptibility to Azithromycin Among Men Who Have Sex with Men - Chicago and Metropolitan Minneapolis-St. Paul, 2014.

Increasing rates of shigellosis among adult males, particularly men who have sex with men (MSM), have been documented in the United States, Canada, and Europe, and MSM appear to be at greater risk for infection with shigellae that are not susceptible to ciprofloxacin or azithromycin. Azithromycin is the first-line empiric antimicrobial treatment for shigellosis among children and is a second-line treatment among adults. Isolates collected in 2014 in two U.S. cities from outbreaks of shigellosis displayed highly similar pulsed-field gel electrophoresis (PFGE) patterns and decreased susceptibility to azithromycin (DSA). This report summarizes and compares the findings from investigations of the two outbreaks, which occurred among MSM in metropolitan Minneapolis-St. Paul, Minnesota, and Chicago, Illinois.

An outbreak of foodborne illness among attendees of a wedding reception in Wisconsin likely caused by Arcobacter butzleri.

BACKGROUND: Arcobacter species, primarily Arcobacter butzleri, are widely distributed among animals, infrequently isolated from humans, and previously not associated with outbreaks of foodborne illness. We report results of an investigation of a foodborne outbreak that occurred among attendees of a wedding reception in Wisconsin, United States, and was likely caused by A. butzleri. METHODS: We conducted a case-control study among reception attendees and a laboratory investigation to determine the extent, source, and cause of the outbreak. A clinical case was defined as diarrhea in an attendee with illness onset ≤7 days following the wedding reception. RESULTS: The case-control study included 47 of 51 case patients and 43 non-ill attendees. Results demonstrated that consuming broasted chicken was the only factor significantly associated with illness (odds ratio 10.51; 95% confidence interval 1.28, 476.4). Five patients provided stool specimens. Comprehensive culture and polymerase chain reaction (PCR) testing did not detect common bacterial or viral pathogens. Subsequent testing with PCRs targeting 16S/23S rDNA of the three most clinically relevant Arcobacter spp. and the rpoB/C gene of A. butzleri provided products confirmed as A. butzleri (four patients) and A. cryaerophilus (one patient) by sequence analysis. CONCLUSIONS: The results of this investigation suggest that A. butzleri should be considered an agent that can cause outbreaks of foodborne illness. Rigorous investigation of outbreaks of undetermined etiology is valuable for incrementally increasing our understanding of emerging agents causing foodborne illnesses.

Salmonellosis outbreak due to chicken contact leading to a foodborne outbreak associated with infected delicatessen workers.

Salmonella is the most common bacterial cause of foodborne outbreaks in the United States. Starting in June 2007, investigation of a cluster of Salmonella Montevideo cases with indistinguishable pulsed-field gel electrophoresis (PFGE) patterns resulted in the identification of an outbreak associated with contact with chickens purchased from a single hatchery. Nine Minnesota cases from May through August 2007 were part of this outbreak. Cases with the outbreak PFGE pattern of Salmonella Montevideo continued to occur in Minnesota after August, but none of these cases reported chicken contact. The majority of these cases resided in the same town in rural Minnesota. Routine interviews revealed that all cases from these counties purchased groceries from the same local grocery store, with two specifically reporting consuming items from the grocery store delicatessen in the week before illness. As a result, an investigation into the delicatessen was initiated. Illness histories and stool samples were collected from all delicatessen employees, and food and environmental samples were collected. None of the employees reported experiencing recent gastrointestinal symptoms, but the outbreak PFGE subtype of Salmonella Montevideo was identified from stool from two food workers. Food and environmental samples collected tested negative for Salmonella. One of the positive employees reported having chickens at home, but the animals did not test positive for Salmonella. The positive food workers were excluded from work until they had two consecutive negative stool cultures for Salmonella. There was no evidence of ongoing transmission thereafter. This was an outbreak of Salmonella Montevideo infections that began as an animal-contact-associated outbreak which subsequently resulted in a foodborne outbreak associated with infected food workers. These outbreaks illustrate the complex epidemiology of salmonellosis.

Salmonella infections in food workers identified through routine Public Health Surveillance in Minnesota: impact on outbreak recognition.

The frequency of Salmonella-infected food workers identified through routine surveillance from 1997 to 2004 in Minnesota was determined in order to evaluate the impact of surveillance on the detection of outbreaks in restaurants and to quantify the duration of Salmonella shedding in stool. Of 4,976 culture-confirmed Salmonella cases reported to the Minnesota Department of Health, 110 (2.2%) were identified as food workers; this was less than one-half the number expected based on the incidence of Salmonella in the general population. Twenty food workers (18%) were associated with outbreaks. Twelve were involved in nine independent outbreaks at the restaurants where they worked. The identification of the index food worker in six of these outbreaks was critical to the initiation of outbreak investigations that revealed much larger problems. Among food workers who submitted specimens until at least one negative result was obtained (n = 69), the median duration of shedding was 22 days (range, 1 to 359 days). Among the four most common serotypes (Enteritidis, Typhimurium, Heidelberg, and Newport) the median duration of shedding was significantly longer for Salmonella Newport (80 days; P = 0.02) and for Salmonella Enteritidis (32 days; P = 0.04) than for Salmonella Heidelberg (8 days). Food workers should be considered an important source of Salmonella transmission, and those identified through surveillance should raise a high index of suspicion of a possible outbreak at their place of work. Food service managers need to be alert to Salmonella-like illnesses among food workers to facilitate prevention and control efforts, including exclusion of infected food workers or restriction of their duties.

Restaurant Salmonella Enteritidis outbreak associated with an asymptomatic infected food worker.

Salmonella is the most common bacterial cause of foodborne outbreaks in the United States; approximately half of Salmonella outbreaks occur in restaurant settings. In February 2008, investigation of a cluster of Salmonella Enteritidis cases with indistinguishable pulsed-field gel electrophoresis (PFGE) patterns revealed that five cases had eaten at the same restaurant. Cases were identified through routine surveillance activities and by contacting meal companions of culture-confirmed cases. Well meal companions and well patrons contacted via check stubs served as controls. Illness histories and stool samples were collected from all restaurant employees. Sandwiches were the only menu item or ingredient significantly associated with illness (15 of 15 cases versus 17 of 37 controls; odds ratio, undefined; P < 0.001). None of the six restaurant employees reported experiencing recent gastrointestinal symptoms. The outbreak PFGE subtype of Salmonella Enteritidis was identified in two food workers. One of the positive employees began working at the restaurant shortly before the first exposure date reported by a case, and assisted in the preparation of sandwiches and other foods consumed by cases. The other positive employee rarely, if ever, handled food. The restaurant did not have a glove use policy. There was no evidence of ongoing transmission after exclusion of the positive food workers. This was a restaurant Salmonella Enteritidis outbreak associated with an asymptomatic infected food worker. Routine PFGE subtyping of Salmonella Enteritidis isolates, routine interviewing of cases, and an iterative approach to cluster investigations allowed for timely identification of the source of an outbreak of Salmonella Enteritidis infections.

Outbreaks of salmonellosis in Minnesota (1998 through 2006) associated with frozen, microwaveable, breaded, stuffed chicken products.

From 1998 through 2006, four outbreaks of salmonellosis associated with raw, frozen, microwaveable, breaded, prebrowned, stuffed chicken products were identified in Minnesota. In 1998, 33 Salmonella Typhimurium cases were associated with a single brand of Chicken Kiev. In 2005, four Salmonella Heidelberg cases were associated with a different brand and variety (Chicken Broccoli and Cheese). From 2005 to 2006, 27 Salmonella Enteritidis cases were associated with multiple varieties of product, predominately of the same brand involved in the 1998 outbreak. In 2006, three Salmonella Typhimurium cases were associated with the same brand of product involved in the 2005 Salmonella Heidelberg outbreak. The outbreak serotype and pulsed-field gel electrophoresis subtype of Salmonella were isolated from product in each outbreak. In these outbreaks, most individuals affected thought that the product was precooked due to its breaded and prebrowned nature, most used a microwave oven, most did not follow package cooking instructions, and none took the internal temperature of the cooked product. Similar to previous salmonellosis outbreaks associated with raw, breaded chicken nuggets or strips in Canada and Australia, inadequate labeling, consumer responses to labeling, and microwave cooking were the key factors in the occurrence of these outbreaks. Modification of labels, verification of cooking instructions by the manufacturer, and notifications to alert the public that these products contain raw poultry, implemented because of the first two outbreaks, did not prevent the other outbreaks. Microwave cooking is not recommended as a preparation method for these types of products, unless they are precooked or irradiated prior to sale.

Emergence of multidrug-resistant Salmonella enterica serotype Newport in Minnesota.

We report a concurrent increase in the number of isolates of Salmonella enterica serotype Newport and the rate of multidrug resistance in S. Newport isolates from animal and human populations in Minnesota. Antimicrobial susceptibility and pulsed-field gel electrophoresis analysis demonstrated heterogeneity of isolates and showed that 1 pulsed-field gel electrophoresis cluster contained most of the multidrug-resistant isolates with a resistance pattern and most class 1 integron isolates, implying the clonal origin of the isolates.

Outbreaks of salmonellosis at elementary schools associated with dissection of owl pellets.

Salmonella enterica serotype Typhimurium outbreaks occurred at two elementary schools after science club students dissected owl pellets. Forty primary cases were identified (26 culture-confirmed). At the first school, pellets were dissected on a cafeteria table, concurrent with after-school child care in the cafeteria. Subsequently, the table was not sanitized before use by after-school care students for snack, or before the next school lunch. At the second school, pellets were dissected in a dedicated science room, and fewer cases occurred. Pellets in both outbreaks originated from a single captive barred owl. The outbreak pulsed-field gel electrophoresis subtype of S. Typhimurium was isolated from the owl's pellets and feces, and from four frozen chicks from a batch used to feed the owl.

Antimicrobial-drug susceptibility of human and animal Salmonella typhimurium, Minnesota, 1997-2003.

We compared antimicrobial resistance phenotypes and pulsed-field gel electrophoresis (PFGE) subtypes of 1,028 human and 716 animal Salmonella enterica serotype Typhimurium isolates from Minnesota from 1997 to 2003. Overall, 29% of human isolates were multidrug resistant. Predominant phenotypes included resistance to ampicillin, chloramphenicol or kanamycin, streptomycin, sulfisoxazole, and tetracycline (ACSSuT or AKSSuT). Most human multidrug-resistant isolates belonged to PFGE clonal group A, characterized by ACSSuT resistance (64%), or clonal group B, characterized by AKSSuT resistance (19%). Most animal isolates were from cattle (n = 358) or swine (n = 251). Eighty-one percent were multidrug resistant; of these, 54% were at least resistance phenotype ACSSuT, and 43% were at least AKSSuT. More than 80% of multidrug-resistant isolates had a clonal group A or B subtype. Resistance to ceftriaxone and nalidixic acid increased, primarily among clonal group A/ACSSuT isolates. Clonal group B/AKSSuT isolates decreased over time. These data support the hypothesis that food animals are the primary reservoir of multidrug-resistant S. Typhimurium.

Outbreaks of enteric infections caused by multiple pathogens associated with calves at a farm day camp.

BACKGROUND: Transmission of enteric pathogens at venues where the public contacts farm animals is a growing problem, particularly among children. In 2000 and again in 2001, enteric illness outbreaks caused by multiple pathogens occurred at a farm day camp for children in Minnesota. METHODS: Camp attendees were interviewed about illness history and potential exposures each year. Stool samples from children and calves at the camp were tested for enteric pathogens. RESULTS: Eighty-four illnesses were documented among camp attendees in the 2 outbreaks; laboratory-confirmed infections included Cryptosporidium parvum (17 cases), Escherichia coli O157:H7 (4), non-O157 Shiga toxin-producing E. coli (STEC) (7) and Salmonella enterica serotype Typhimurium and Campylobacter jejuni (1 each). Kindergarten-fourth grade children provided 1-on-1 care for a bottle-fed calf. Sixty of 83 calves tested carried at least 1 pathogen, including Giardia spp. (26 calves), C. parvum (25), non-O157 STEC (17), Campylobacter spp. (11), 3 serotypes of Salmonella enterica (10) and E. coli O157:H7 (2). Risk factors among children included caring for an ill calf and getting visible manure on their hands. Always washing hands with soap after touching a calf and washing hands before going home were protective. Prevention measures implemented in 2000 failed to prevent the second outbreak. CONCLUSIONS: Calves were the reservoir of multiple enteric pathogens for children at a farm day camp. Health care providers should consider numerous zoonotic pathogens in patients presenting with gastroenteritis after contact with cattle. Public health officials should help venue operators prospectively implement published guidelines to prevent zoonotic disease transmission.