[New regulations concerning EHEC/VTEC]. / Nya rutiner för smittskydds­åtgärder vid EHEC-infektion - Endast EHEC som bär på stx2-genen kan kopplas till HUS ­ dessa smittbärare måste avstängas från arbete eller förskola.

New regulations concerning EHEC/VTEC Hemolytic Uremic Syndrome (HUS) is the most severe complication to an infection with EHEC (enterohemorrhagic E. coli), also called VTEC (verocytotoxin-producing E. coli). Risk of severe complications such as HUS is an important reason why the Swedish Communicable Diseases Act (Smittskyddslag. 2004:168) includes infection with EHEC. With very few exceptions, only EHEC with the stx2 gene is associated with HUS. According to the law, persons working with unpackaged foods, infants or severely immunocompromised patients, and children attending preschool can be suspended awaiting negative test results for EHEC. Symptom free carriers of EHEC-infection only harbouring the stx1 gene and without an epidemiological association to HUS need not be suspended from work or preschool.

Investigation of a food-borne outbreak of gastroenteritis in a school canteen revealed a variant of sapovirus genogroup V not detected by standard PCR, Sollentuna, Sweden, 2016.

A food-borne outbreak of gastroenteritis with more than 650 suspected cases occurred in April 2016 in Sollentuna, Sweden. It originated in a school kitchen serving a total of 2,700 meals daily. Initial microbiological testing (for Campylobacter, Salmonella, Shigella, Yersinia, Giardia, Cryptosporidium, Entamoeba histolytica, adeno-, astro-, noro-, rota- and sapovirus) of stool samples from 15 symptomatic cases was negative, despite a clinical presentation suggestive of calicivirus. Analyses of the findings from both the Sollentuna municipality environmental team and a web-based questionnaire suggested that the source of the outbreak was the salad buffet served on 20 April, although no specific food item could be identified. Subsequent electron microscopic examination of stool samples followed by whole genome sequencing revealed a variant of sapovirus genogroup V. The virus was not detected using standard PCR screening. This paper describes the epidemiological outbreak investigation and findings leading to the discovery.

Unusual cryptosporidiosis cases in Swedish patients: extended molecular characterization of Cryptosporidium viatorum and Cryptosporidium chipmunk genotype I.

Most human cases of cryptosporidiosis are caused by Cryptosporidium parvum or Cryptosporidium hominis, but the use of molecular diagnostic methods has revealed that several other less common species or genotypes can also be involved. Here, we describe two unusual causes of cryptosporidiosis, one being the recently described species Cryptosporidium viatorum and the other Cryptosporidium chipmunk genotype I. Two Swedish patients who were infected with C. viatorum had travelled to Kenya and Guatemala, respectively, and two others had been infected with Cryptosporidium chipmunk genotype I in Sweden. None of these four patients were immunocompromised, and all four showed classical symptoms of cryptosporidiosis. We performed extensive molecular characterization, including analysis of four loci. The two C. viatorum isolates were found to differ slightly at the 70-kDa heat shock protein locus, which may indicate a local geographical variation in this species that has previously been described exclusively on the Indian subcontinent.

Multilocus genotyping of human Giardia isolates suggests limited zoonotic transmission and association between assemblage B and flatulence in children.

BACKGROUND: Giardia intestinalis is one of the most common diarrhea-related parasites in humans, where infection ranges from asymptomatic to acute or chronic disease. G. intestinalis consists of eight genetically distinct genotypes or assemblages, designated A-H, and assemblages A and B can infect humans. Giardiasis has been classified as a possible zoonotic disease but the role of animals in human disease transmission still needs to be proven. We tried to link different assemblages and sub-assemblages of G. intestinalis isolates from Swedish human patients to clinical symptoms and zoonotic transmission. METHODOLOGY/PRINCIPAL FINDINGS: Multilocus sequence-based genotyping of 207 human Giardia isolates using three gene loci: ß-giardin, glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) was combined with assemblage-specific tpi PCRs. This analysis identified 73 patients infected with assemblage A, 128 with assemblage B, and six with mixed assemblages A+B. Multilocus genotypes (MLGs) were easily determined for the assemblage A isolates, and most patients with this genotype had apparently been infected through anthroponotic transmission. However, we also found evidence of limited zoonotic transmission of Giardia in Sweden, since a few domestic human infections involved the same assemblage A MLGs previously reported in Swedish cats and ruminants. Assemblage B was detected more frequently than assemblage A and it was also more common in patients with suspected treatment failure. However, a large genetic variability made determination of assemblage B MLGs problematic. Correlation between symptoms and assemblages was found only for flatulence, which was significantly more common in children less than six years of age infected with assemblage B. CONCLUSIONS/SIGNIFICANCE: This study shows that certain assemblage A subtypes are potentially zoonotic and that flatulence is connected to assemblage B infections in young children. Determination of MLGs from assemblages A and B can be a valuable tool in outbreak situations and to help identify possible zoonotic transmission.

Effectiveness of an adjuvanted monovalent vaccine against the 2009 pandemic strain of influenza A(H1N1)v, in Stockholm County, Sweden.

BACKGROUND: Vaccination against the pandemic influenza A(H1N1)v was performed in many countries during 2009, but population-based data on vaccine effectiveness are lacking. METHODS: We conducted a prospective cohort study involving all inhabitants in Stockholm County (n = 2,019,183) who were offered a monovalent AS03-adjuvanted influenza A(H1N1)v vaccine (Pandemrix, GSK), between 12 October and 31 December 2009. Overall vaccine coverage was 52%. A Web-based register with data on all vaccinated was linked by unique personal identification number to mandatory reports of influenza A(H1N1)v diagnoses. Vaccine failure was defined as a diagnosis or admission to hospital because of influenza >14 days after vaccination. Risk factors associated with vaccine failure were investigated by conditional stepwise logistic regression in a nested case-control study. The weekly incidence rate ratio for being diagnosed with influenza among vaccinated versus nonvaccinated persons was calculated. RESULTS: Vaccine failure was seen in 25 patients, 11 children and 14 adults, of 2594 patients diagnosed with influenza A(H1N1)v. Compared with age-matched controls, patients with vaccine failure were more often immunocompromised (Hazard Ratio, 4.89; 95% confidence interval [CI], 2.19-10.89). During the 4 weeks with maximum influenza activity, the relative risk per week for an influenza A(H1N1)v diagnosis in the vaccinated population was .06 (95% CI .008-.41), .13 (95% CI .06-.27), .05 (95% CI .02-.12), and .07 (95% CI .03-.15), respectively, corresponding to a weekly vaccine effectiveness of 87-95%. CONCLUSIONS: The monovalent AS03-adjuvanted influenza vaccine was highly effective in prevention of the pandemic influenza in Stockholm County. A single dose seemed to be sufficient in most, both children and adults, except in immunocompromised hosts.

A foodborne outbreak of Cyclospora infection in Stockholm, Sweden.

During May and June 2009 an outbreak of Cyclospora cayetanensis infection involving 12 laboratory-confirmed and 6 probable cases was detected in Stockholm County, Sweden. Imported sugar snap peas from Guatemala were the suspected vehicle, based on information obtained from patient questionnaires. This is the first reported outbreak of cyclosporiasis in Sweden and the second in Europe.

Increased sporulation rate of epidemic Clostridium difficile Type 027/NAP1.

Clostridium difficile PCR ribotype 027 comprised 0.2% of a collection of Swedish isolates in 1997-2001 (3 of 1,325 isolates). These isolates had lower moxifloxacin MICs than the epidemic type 027 isolates, but they had the same tcdC sequence and toxin yield. Type 027 produced 3- to 13-fold more toxin than did major Swedish types. One epidemic strain (027/NAP1a) sporulated more than did other type 027 isolates, a feature that should contribute to its survival and spread.

Gastrointestinal symptoms after infectious diarrhea: a five-year follow-up in a Swedish cohort of adults.

BACKGROUND & AIMS: Gastrointestinal infection is a well-recognized trigger for functional bowel disorder. This study evaluated gastrointestinal symptoms and risk factors for their development after diarrheal disease of proven or strongly suspected infectious etiology in adults. METHODS: The cohort of patients was derived from a previous study that determined the rate at which enteropathogens could be isolated at the time of diarrheal disease in adults. After 5 years, 717 of 851 patients were accessible for a questionnaire asking for persistence of gastrointestinal symptoms. RESULTS: Of 508 returned questionnaires, 333 were from patients with no previous gastrointestinal complaints. Forty-one (12%) of them had gastrointestinal symptoms for 3 months or more after the infectious diarrhea, and 31 (9%) still had symptoms at the end of the follow-up period. Irritable bowel syndrome was most common (68%), but other functional bowel disorder diagnoses were found in all but one of the others. Female gender (odds ratio, 2.65, 95% confidence interval, 1.28-5.50) and use of antibiotic treatment (odds ratio, 2.37; 95% confidence interval, 1.07-5.25) were risk factors for development of postinfectious functional bowel disorder. No increase in risk was associated with the type of enteropathogen causing diarrhea. CONCLUSIONS: Infectious diarrhea in previously healthy adults carried a substantial risk of triggering postinfectious functional bowel disorder. Irritable bowel syndrome was the most common, but other functional bowel disorders were also found. We did not find any new clinical tools that would facilitate the prediction of long-standing symptoms.

Antimicrobial susceptibility pattern of Clostridium difficile and its relation to PCR ribotypes in a Swedish university hospital.

All 238 Clostridium difficile isolates were susceptible to metronidazole and vancomycin, whereas 84% and 1% were resistant to clindamycin and fusidic acid. Etest MICs for metronidazole were lower than agar dilution MICs (P < 0.01) but without difference in susceptible-intermediate-resistant categorization. No particular PCR ribotype was associated with clindamycin or fusidic acid resistance.

Correlation of disease severity with fecal toxin levels in patients with Clostridium difficile-associated diarrhea and distribution of PCR ribotypes and toxin yields in vitro of corresponding isolates.

We investigated in vivo and in vitro yields of toxins A and B from and PCR ribotypes of Clostridium difficile isolates from 164 patients with differing severities of C. difficile-associated diarrhea (CDAD) (patients were grouped as follows: <3 loose stools per day, n = 45; 3 to 10 per day, n = 97; >10 per day, n = 22). The median fecal toxin levels in each group were 0.5, 6.8, and 149 U/g feces (P < 0.001), respectively. Patients with severe diarrhea also had more-frequent occurrence of blood in stool and vomiting, but there was no association with fecal toxin levels per se. There was no correlation between fecal toxin level and toxin yield in vitro for the corresponding C. difficile isolate or between its PCR ribotype and disease severity. A broad range of toxin yields among isolates belonging to major PCR ribotypes indicated a presence of many subtypes. We hypothesize that bacterial and host factors that affect C. difficile toxin levels in feces are important determinants of symptoms in CDAD patients. An inverse correlation between toxin yield and spore count (r = 0.66) in stationary-phase cultures supported the notion that toxin production and sporulation represent opposite alternative survival strategies for C. difficile cells facing nutrient shortage.

An outbreak of cryptosporidiosis associated with exposure to swimming pool water.

An outbreak of cryptosporidiosis among visitors to a public swimming pool occurred in the late summer of 2002. We performed a retrospective cohort study, including 3 cohorts, A) 178 school-children who visited the pool on a single occasion, B) 263 arbitrarily chosen school children, aged 6-12 y, and their household members, living within the municipality where the outbreak occurred, and C) an additional 28 individuals with laboratory confirmed cryptosporidiosis. The outbreak lasted 4 weeks and affected an estimated 800-1000 individuals. The primary attack rate was 40-50%. The median incubation period was 5 d (range 2-13 d). The secondary attack rate was 8-10%. Diarrhoea was reported by 93% of the patients, abdominal pain 89%, nausea 73%, and fever 40%. Fifty-four percent had<5 loose stools and 20% had>10 loose stools per d. The duration of symptoms was 4-10 d for 52% and>10 d for 34% of the cases. This is the first reported outbreak of pool associated cryptosporidiosis in Sweden and emphasizes the importance of proper control routines of swimming pools with continuous assessment of the quality of the water sources and filtration processes.

Effect of Lactobacillus F19 on the emergence of antibiotic-resistant microorganisms in the intestinal microflora.

OBJECTIVES: Probiotic lactic-acid-producing bacteria have been used for prevention of gastrointestinal diseases. The aim of the present study was to examine whether Lactobacillus F19 in conjunction with treatment with penicillin, ciprofloxacin or norfloxacin prevents establishment of resistant bacteria in the gastrointestinal tract. METHODS: Twenty patients admitted to hospital due for treatment with penicillin and 16 patients due for treatment with ciprofloxacin or norfloxacin were included in the study. In either group, the patients were randomized into two groups, receiving placebo or an active probiotic product. Faecal samples were collected before treatment, on day 10 and 1 month after the start of the treatment. Isolates of enterococci, enterobacteria and Bacteroides fragilis species were screened for resistance to penicillin and ciprofloxacin, respectively. RESULTS: Administration of penicillin did not influence resistance in enterococci while quinolone resistance increased during quinolone treatment. Susceptibility to ampicillin and piperacillin/tazobactam decreased in enterobacteria during penicillin treatment and ciprofloxacin resistance increased in the quinolone group. Penicillin and quinolones did not influence the resistance rates of Bacteroides isolates. No major differences were observed between the probiotic- and placebo-supplemented groups. CONCLUSIONS: There was a limited effect of Lactobacillus F19 on the emergence of resistant isolates during treatment with penicillin and quinolones.

Rectal nitric oxide gas and stool cytokine levels during the course of infectious gastroenteritis.

Nitric oxide (NO) is known to be an important inflammatory mediator with a potential role in gastrointestinal diseases. We prospectively studied the luminal NO levels in 51 patients with infectious gastroenteritis, 35 patients with nonenteric bacterial infections, and 11 healthy control subjects. The levels of proinflammatory cytokines were simultaneously measured in the stools of patients with gastroenteritis. Rectal gas was sampled with balloon catheters made of silicone and was analyzed for NO levels by chemiluminescence. The median rectal NO level was 2,450 ppb in the acute phase of gastroenteritis and gradually decreased to 225 ppb after 3 to 8 weeks, whereas the median NO values were 150 ppb in patients with nonenteric bacterial infections and 100 ppb in healthy control subjects. Patients with Salmonella, Shigella, and Campylobacter infections generally had more severe symptoms and a higher median NO level (17,250 ppb) than patients with Clostridium difficile-associated diarrhea (median NO value, 275 ppb). Interleukin-1 beta levels were elevated in 82% of the patients at disease onset and decreased during the convalescent phase. In contrast, gamma interferon was detected in only 16% of the patients and was predominantly collected in stool samples collected during the subacute and convalescent stages. Our data point to the possibility of using this easy, minimally invasive method for luminal NO measurement as a diagnostic tool, among others, to evaluate the degree of intestinal inflammation in patients with infectious gastroenteritis.

Epidemiology and molecular characterization of Clostridium difficile strains from patients with diarrhea: low disease incidence and evidence of limited cross-infection in a Swedish teaching hospital.

We prospectively studied the epidemiology of Clostridium difficile-associated diarrhea (CDAD) in a 900-bed hospital over the course of 12 months by PCR-ribotyping of C. difficile isolates. A total of 304 cases were diagnosed, corresponding to an overall incidence of 7/1,000 admissions, with higher rates in nephrology, hematology, and organ transplantation wards (37, 30, and 21/1,000), and 72% were classified as hospital associated (onset in hospital or onset at home but after a hospital stay within 2 months). All 382 isolates from 227 of 304 (75%) patients available for PCR-ribotyping were typeable, yielding 70 PCR-ribotypes. The three most common types comprised 30% of hospital-associated and 34% of community-associated cases, indicating import via admitted patients as a major source of C. difficile strains occurring in the hospital. Of the 227 patients studied, 38% each contributed 2 to 13 fecal samples positive for C. difficile over the course of the study period. Repeat isolates of the same PCR-ribotype as the first isolate were found in 79% of these patients and in 95% of specimens delivered within 30 days, compared to 63% of those obtained at 31 to 204 days. Nosocomial acquisition of CDAD, defined as the proportion of cases sharing C. difficile type and admitted to the same ward within 2 or 12 months, was 20% and 32% of hospital-associated cases and 14% and 23% of all cases, respectively. Thus, most CDAD cases diagnosed over the course of the study period, including those associated with hospitalization, appeared to be caused by endogenous C. difficile strains rather than by strains truly being acquired in the hospital.