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.

Burdens of Invasive Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus Disease, Minnesota, USA.

During August 1, 2014-July 31, 2015, in 2 counties in Minnesota, USA, incidence of invasive methicillin-susceptible Staphylococcus aureus (MSSA) (27.1 cases/100,000 persons) was twice that of invasive methicillin-resistant S. aureus (13.1 cases/100,000 persons). MSSA isolates were more genetically diverse and susceptible to more antimicrobial drugs than methicillin-resistant S. aureus isolates.

Changes in Predominance of Pulsed-Field Gel Electrophoresis Profiles of Bordetella pertussis Isolates, United States, 2000-2012.

To clarify the characteristics of circulating Bordetella pertussis isolates, we used pulsed-field gel electrophoresis (PFGE) to analyze 5,262 isolates collected in the United States during 2000-2012. We found 199 PFGE profiles; 5 profiles accounted for 72% of isolates. The most common profile, CDC013, accounted for 35%-46% of isolates tested from 2000-2009; however, the proportion of isolates of this profile rapidly decreased in 2010. Profile CDC237, first seen in 2009, increased rapidly and accounted for 29% of 2012 isolates. No location bias was observed among profiles during 2000-2010, but differences were observed among isolates from different states during 2012. Predominant profiles match those observed in recent European PFGE studies. PFGE profile changes are concurrent with other recent molecular changes in B. pertussis and may be contributing to the reemergence of pertussis in the United States. Continued PFGE monitoring is critical for understanding the changing epidemiology of pertussis.

Complete genome sequences of sucrose non-fermenting non-O1/non-O139 Vibrio cholerae isolated from human soft tissue infection.

This paper describes the hybrid genome assembly of sucrose non-fermenting non-O1/non-O139 Vibrio cholerae isolated from human soft tissue infection. The hybrid assembled genome comprises two circular chromosomes with lengths of 3,001,999 bp and 1,264,051 bp, respectively, with a G + C content of 47.38%.

Comparative genome sequencing of an isogenic pair of USA800 clinical methicillin-resistant Staphylococcus aureus isolates obtained before and after daptomycin treatment failure.

We describe here a clinical daptomycin treatment failure in a patient with recurrent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in whom daptomycin was administered after a failed empirical treatment course with vancomycin and piperacillin-tazobactam. We had the opportunity to compare the genome sequences of an isogenic pair of daptomycin-susceptible and -resistant MRSA isolates obtained before and after initiation of daptomycin therapy, respectively. The genotype of both isolates was USA800, ST5, SCCmec type IV, agr type II. There was no increase in cell wall thickness in the daptomycin-resistant strain despite having decreased susceptibility to both vancomycin and daptomycin. By comparing the genome sequences by pyrosequencing, we identified a polymorphism (S337L) in the tenth transmembrane segment of the multiple peptide resistance factor, MprF, encoding lysyl phosphatidylglycerol transferase. This enzyme has been shown previously to promote repulsion of daptomycin at the cell surface by addition of positively charged lysine to phosphatidylglycerol. Also, the hlb open reading frame (ORF) encoding the ß-toxin was interrupted by a prophage in the daptomycin-susceptible strain; this phage was missing in the daptomycin-resistant isolate and the hlb ORF was restored. Loss of the phage in the resistant isolate also resulted in loss of the virulence factor genes clpP, scn, and sak. This is the first study to use pyrosequencing to compare the genomes of a daptomycin-susceptible/resistant MRSA isolate pair obtained during failed daptomycin therapy in humans.

Campylobacter jejuni genotypes are associated with post-infection irritable bowel syndrome in humans.

Campylobacter enterocolitis may lead to post-infection irritable bowel syndrome (PI-IBS) and while some C. jejuni strains are more likely than others to cause human disease, genomic and virulence characteristics promoting PI-IBS development remain uncharacterized. We combined pangenome-wide association studies and phenotypic assays to compare C. jejuni isolates from patients who developed PI-IBS with those who did not. We show that variation in bacterial stress response (Cj0145_phoX), adhesion protein (Cj0628_CapA), and core biosynthetic pathway genes (biotin: Cj0308_bioD; purine: Cj0514_purQ; isoprenoid: Cj0894c_ispH) were associated with PI-IBS development. In vitro assays demonstrated greater adhesion, invasion, IL-8 and TNFα secretion on colonocytes with PI-IBS compared to PI-no-IBS strains. A risk-score for PI-IBS development was generated using 22 genomic markers, four of which were from Cj1631c, a putative heme oxidase gene linked to virulence. Our finding that specific Campylobacter genotypes confer greater in vitro virulence and increased risk of PI-IBS has potential to improve understanding of the complex host-pathogen interactions underlying this condition.

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.

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.

Randomized controlled trial of a self-administered five-day antiseptic bundle versus usual disinfectant soap showers for preoperative eradication of Staphylococcus aureus colonization.

OBJECTIVE: To determine the efficacy in eradicating Staphylococcus aureus (SA) carriage of a 5-day preoperative decolonization bundle compared to 2 disinfectant soap showers, with both regimens self-administered at home. DESIGN: Open label, single-center, randomized clinical trial. SETTING: Ambulatory orthopedic, urologic, neurologic, colorectal, cardiovascular, and general surgery clinics at a tertiary-care referral center in the United States.ParticipantsPatients at the University of Minnesota Medical Center planning to have elective surgery and not on antibiotics. METHODS: Consenting participants were screened for SA colonization using nasal, throat, axillary, and perianal swab cultures. Carriers of SA were randomized, stratified by methicillin resistance status, to a decolonization bundle group (5 days of nasal mupirocin, chlorhexidine gluconate [CHG] bathing, and CHG mouthwash) or control group (2 preoperative showers with antiseptic soap). Colonization status was reassessed preoperatively. The primary endpoint was absence of SA at all 4 screened body sites. RESULTS: Of 427 participants screened between August 31, 2011, and August 9, 2016, 127 participants (29.7%) were SA carriers. Of these, 121 were randomized and 110 were eligible for efficacy analysis (57 decolonization bundle group, 53 control group). Overall, 90% of evaluable participants had methicillin-susceptible SA strains. Eradication of SA at all body sites was achieved for 41 of 57 participants (71.9%) in the decolonization bundle group and for 13 of 53 participants (24.5%) in the control group, a difference of 47.4% (95% confidence interval [CI], 29.1%-65.7%; P<.0001). CONCLUSION: An outpatient preoperative antiseptic decolonization bundle aimed at 4 body sites was significantly more effective in eradicating SA than the usual disinfectant showers (ie, the control).Trial RegistrationClinicalTrials.gov identifier: NCT02182115.

Prevalence and Molecular Characteristics of Clostridium difficile in Retail Meats, Food-Producing and Companion Animals, and Humans in Minnesota.

Community-associated Clostridium difficile infection (CA-CDI) now accounts for approximately 50% of CDI cases in central Minnesota; animals and meat products are potential sources. From November 2011 to July 2013, we cultured retail meat products and fecal samples from food-producing and companion animals in central Minnesota for C. difficile by using standard methods. The resulting 51 C. difficile isolates, plus 30 archived local veterinary C. difficile isolates and 208 human CA-CDI case isolates from central Minnesota (from 2012) from the Minnesota Department of Health, were characterized molecularly, and source groups were compared using discriminant analysis. C. difficile was recovered from 0 (0%) of 342 retail meat samples and 51 (9%) of 559 animal fecal samples. Overall, the 81 animal source isolates and 208 human source isolates were highly diverse genetically. Molecular traits segregated extensively in relation to animal versus human origin. Discriminant analysis classified 95% of isolates correctly by source group; only five (2.5%) human source isolates were classified as animal source. These data do not support meat products or food-producing and companion animals as important sources of CA-CDI in the central Minnesota study region.

Risk factors for household transmission of community-associated methicillin-resistant Staphylococcus aureus.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a community pathogen. Community-associated (CA) MRSA infections have occurred among multiple members of a household. We describe the incidence of and risk factors for MRSA colonization among household contacts of children with CA-MRSA infections. METHODS: MRSA-infected children <18 years of age who lacked established healthcare-associated MRSA risk factors were identified through surveillance at 12 Minnesota hospital laboratories. Nasal swab specimens and information on medical history and hygiene behaviors were collected from case-patients and enrolled household contacts during home visits. S. aureus isolates obtained from nasal cultures were screened for oxacillin resistance. RESULTS: In all, 236 households consisting of 236 case-patients and 712 household contacts were enrolled. Home visits were conducted on an average of 69 days after the onset of symptom in case-patients (range: 16-178 days). Twenty-nine (13%) case-patients and 82 (12%) household contacts had MRSA nasal colonization. Nasal MRSA colonization in ≥ 1 household contact occurred in 58 (25%) households. Household contacts who assisted the case-patient to bathe or who shared balms/ointments/lotion with the case-patient were more likely to be colonized (P < 0.01, P < 0.05), whereas those who reported using antibacterial versus nonantibacterial soap for hand washing were less likely to be colonized (P < 0.05) with MRSA clonally related to the case-patient infection isolate. CONCLUSIONS: Only 13% of case-patients had MRSA nasal colonization on an average of 69 days after their initial MRSA infection. CA-MRSA colonization may be short-lived or may occur at non-nasal sites. One quarter of households had at least one household contact colonized with MRSA. Modifiable behaviors, such as sharing personal items, may contribute to transmission.

Use of streptogramin growth promoters in poultry and isolation of streptogramin-resistant Enterococcus faecium from humans.

BACKGROUND: Virginiamycin use in poultry selects for Enterococcus faecium with cross-resistance to quinupristin-dalfopristin, a drug for vancomycin-resistant E. faecium in humans. We conducted an epidemiologic study of poultry exposures as risk factors for human carriage of quinupristin-dalfopristin-resistant E. faecium. METHODS: Rectal or fecal samples for E. faecium testing were obtained from 567 newly admitted hospital patients and 100 healthy vegetarians. Participants were interviewed regarding poultry exposure. Retail poultry washes (160 conventional and 26 antibiotic free) were also tested for the presence of E. faecium. Constitutive and inducible quinupristin-dalfopristin resistance were assessed in E. faecium isolates, and resistance genes were identified by polymerase chain reaction. RESULTS: E. faecium was isolated from 105 patients, 65 vegetarians, and 77 conventional and 23 antibiotic-free poultry washes. Constitutive quinupristin-dalfopristin resistance was absent in human E. faecium, but 56% of conventional poultry isolates were quinupristin-dalfopristin resistant. Inducible quinupristin-dalfopristin resistance was more common in samples from patients than in those from vegetarians and in washes of conventional than antibiotic-free poultry. Higher poultry consumption was associated with inducible quinupristin-dalfopristin resistance. vatE was present in 38% of E. faecium isolates from patients and none from vegetarians. Touching raw poultry was associated with the presence of vatE. CONCLUSIONS: Poultry exposure is associated with a quinupristin-dalfopristin resistance gene and inducible quinupristin-dalfopristin resistance in human fecal E. faecium. The continued use of virginiamycin may increase the potential for streptogramin-resistant E. faecium infection in humans.