In November 2010, ≈27,000 (≈45%) inhabitants of Östersund, Sweden, were affected by a waterborne outbreak of cryptosporidiosis. The outbreak was characterized by a rapid onset and high attack rate, especially among young and middle-aged persons. Young age, number of infected family members, amount of water consumed daily, and gluten intolerance were identified as risk factors for acquiring cryptosporidiosis. Also, chronic intestinal disease and young age were significantly associated with prolonged diarrhea. Identification of Cryptosporidium hominis subtype IbA10G2 in human and environmental samples and consistently low numbers of oocysts in drinking water confirmed insufficient reduction of parasites by the municipal water treatment plant. The current outbreak shows that use of inadequate microbial barriers at water treatment plants can have serious consequences for public health. This risk can be minimized by optimizing control of raw water quality and employing multiple barriers that remove or inactivate all groups of pathogens.

Sonication of implants has been shown to be a promising method for diagnosis of prosthetic infections due to its improved sensitivity, simplicity, and low cost. The aim of the present study was to evaluate the effects of ultrasound performed under different conditions regarding temperature, duration, and composition of sonication tubes on bacterial species often associated with prosthetic infections. We found that ultrasound had an inhibitory effect on bacteria, of which gram-negative bacteria, in particular Escherichia coli, were almost eradicated after 5 min of sonication at 35°C. Gram-positive bacteria were found to be resistant to the effect of ultrasound. Four factors were important for the inhibitory effect of sonication: the type of microorganism, the temperature of the sonication buffer, the duration of exposure to ultrasound (minutes), and the material and composition of the sonication tube in which sonication is performed. On the basis of the results from the present study, we propose a protocol for sonication and recovery of bacteria associated with biofilm on infected implants prior to conventional culture. From the present protocol, we recommend sonication for 7 min at 22°C at the maximum effect which permits survival of gram-negative bacteria.

Coagulase-negative staphylococci (CoNS), originally described as ubiquitous commensals of the healthy human skin and mucosa, have emerged as important opportunistic pathogens primarily causing healthcare-associated infections in patients with indwelling medical devices. Recent studies, utilizing new molecular typing methods, particularly on Staphylococcus epidermidis, have increased our understanding of the mechanisms that contribute to the evolutionary success of these extremely versatile microorganisms. In the following mini-review, we summarize recent research in this area focusing on the molecular methods and epidemiology of S. epidermidis and S. saprophyticus.

The outbreak was caused by diverse clones of F. tularensis that occurred concomitantly, were widespread, and apparently persisted in the environment. Multiple independent acquisitions of F. tularensis from the environment over a short time period suggest that natural outbreaks of respiratory tularemia are triggered by environmental cues. The findings additionally caution against interpreting genome sequence identity for this pathogen as proof of a direct epidemiological link.

SUMMARYFor the purpose of developing a national system for outbreak surveillance, local outbreak signals were compared in three sources of syndromic data – telephone triage of acute gastroenteritis, web queries about symptoms of gastrointestinal illness, and over-the-counter (OTC) pharmacy sales of antidiarrhoeal medication. The data sources were compared against nine known waterborne and foodborne outbreaks in Sweden in 2007–2011. Outbreak signals were identified for the four largest outbreaks in the telephone triage data and the two largest outbreaks in the data on OTC sales of antidiarrhoeal medication. No signals could be identified in the data on web queries. The signal magnitude for the fourth largest outbreak indicated a tenfold larger outbreak than officially reported, supporting the use of telephone triage data for situational awareness. For the two largest outbreaks, telephone triage data on adult diarrhoea provided outbreak signals at an early stage, weeks and months in advance, respectively, potentially serving the purpose of early event detection. In conclusion, telephone triage data provided the most promising source for surveillance of point-source outbreaks.

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Using pulsed-field gel electrophoresis (PFGE) we have previously described the occurrence and possible dissemination of a clone of multidrug-resistant Staphylococcus epidermidis (MDRSE) in 2 hospitals in northern Sweden during 2001-2003. The aims of the present study were to investigate if this clone still persisted, 7 y later, in these 2 hospitals and whether this specific clone was detectable among clinical isolates from 9 other hospitals, 6 Swedish as well as a Norwegian, Danish and a German hospital. In total, 173 clinical isolates of MDRSE isolated during 2003 to 2008 were analysed using PFGE, of which 22 isolates were also characterized by multilocus sequence typing (MLST). Two dominating PFGE types (types A and B) were identified, consisting of 56 (32%) and 38 (22%) isolates, respectively. Type A, which was detected in the Norwegian and all Swedish hospitals, proved indistinguishable to the clone previously identified in 2001-2003 and corresponded with a novel sequence type (ST215). Type B was discovered in the German, Danish and in 7 Swedish hospitals and corresponded with ST2. In conclusion, we have demonstrated the occurrence, persistence and potential dissemination of 2 MDRSE genotypes, including a novel sequence type (ST215), within hospitals in northern Europe.

BackgroundIn 2010–2011, two large waterborne outbreaks caused by Cryptosporidium hominis affected two cities in Sweden, Östersund and Skellefteå. We investigated potential post-infection health consequences in people who had reported symptoms compatible with cryptosporidiosis during the outbreaks using questionnaires.MethodsWe compared cases linked to these outbreaks with non-cases in terms of symptoms present up to eleven months after the initial infection. We examined if cases were more likely to report a list of symptoms at follow-up than non-cases, calculating odds ratios (OR) and 95 % confidence intervals (CI) obtained through logistic regression.ResultsA total of 872 (310 cases) and 743 (149 cases) individuals responded to the follow-up questionnaires in Östersund and Skellefteå respectively. Outbreak cases were more likely to report diarrhea (Östersund OR: 3.3, CI: 2.0-5.3. Skellefteå OR: 3.6, CI: 2.0-6.6), watery diarrhea (Östersund OR: 3.4, CI: 1.9-6.3. Skellefteå OR: 2.8, CI: 1.5-5.1) abdominal pain (Östersund OR: 2.1, CI: 1.4-3.3, Skellefteå OR: 2.7, CI: 1.5-4.6) and joint pain (Östersund OR: 2.0, CI: 1.2-3.3, Skellefteå OR: 2.0, CI: 1.1-3.6) at follow-up compared to non-cases.ConclusionsOur findings suggest that gastrointestinal- and joint symptoms can persist several months after the initial infection with Cryptosporidium and should be regarded as a potential cause of unexplained symptoms in people who have suffered from the infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-1871-6) contains supplementary material, which is available to authorized users.