[An outbreak of giardiasis in a child day-care centre in Trondheim]. / Utbrudd av giardiasis i en barnehage i Trondheim.

BACKGROUND: The prevalence of Giardia in Norway is considered to be low, but the infection is probably under-diagnosed. In other countries, child day-care centres have turned out to be major sites of Giardiasis contamination and outbreaks. We report the first giardiasis-outbreak registered in Norway. MATERIALS AND METHODS: The outbreak occurred in a child day-care centre in Trondheim, Norway in 2004. Out of 12 microbiologically verified cases, 9 had clinical gastroenteritis. Stool samples were collected from all children and staff in the day-care centre, and from all household members of identified carriers. All carriers were treated with metronidazole and responded well to treatment. The environment of the child day-care centre was assessed, and all affected households were interviewed by telephone. Preventative measures were implemented. RESULTS AND INTERPRETATION: The outbreak may have started in November 2003 and lasted until July 2004. It was limited to one of the day-care centre's five sections and 44% were infected. The source of infection was not identified, but there are several possibilities: staff who changed nappies and helped with going to the toilet also prepared and served food. Washbasin taps in kitchens and nappy-changing rooms were hand-operated. Cups used for drinking were exposed to potential contamination. These conditions are regarded as important routes for infections.

Real-time PCR targeting the sip gene for detection of group B Streptococcus colonization in pregnant women at delivery.

Group B streptococcus (GBS) is an important aetiological agent of serious neonatal infections. A rapid and sensitive method for the detection of GBS colonization in pregnant women at delivery could make intrapartum screening for GBS possible. A real-time PCR method targeting the sip gene of GBS in pregnant women at delivery has been evaluated. The performance of the real-time PCR was compared with optimized GBS culture. Separate vaginal and rectal swabs were collected from women hospitalized at the delivery department at St Olavs Hospital, Trondheim, Norway, from January 15 through May 2005. The specimens were cultured on selective blood agar plates and in selective broth and examined by real-time PCR. Of samples from 251 women, 87 (34.7%) were GBS positive by culture and 86 (34.3%) were positive by PCR. Using GBS culture as the 'gold standard', the sensitivity of real-time PCR was 0.97 (95% confidence interval 0.90-0.99) and specificity was 0.99 (95% confidence interval 0.97-1.00). In two women the PCR was positive and the culture negative. Additional analysis using cylE PCR substantiates that these two women were true GBS carriers with negative GBS culture. The rate of GBS colonization was lower in vaginal specimens than in rectal specimens both by culture and PCR. The real-time PCR assay is fast, highly sensitive and specific for detecting GBS colonization in pregnant women at delivery, and has the potential for intrapartum detection of GBS colonization. Both vaginal and rectal samples are required to achieve highest possible detection rate.

Identification of virulence genes linked with diarrhea due to atypical enteropathogenic Escherichia coli by DNA microarray analysis and PCR.

The role of atypical enteropathogenic Escherichia coli (EPEC) in childhood diarrhea is controversial. The aim of the present study was to search for genes linked with diarrhea in atypical EPEC strains from a case-control study among Norwegian children. Using DNA microarray analysis, genomic DNAs from strains isolated from children with (n = 37) and without (n = 20) diarrhea were hybridized against 242 different oligonucleotide probes specific for 182 virulence genes or markers from all known E. coli pathotypes. PCR was performed to test the strains for seven putative virulence genes not included in the microarray panel. The OI-122 gene efa1/lifA was the gene with the strongest statistical association with diarrhea (P = 0.0008). Other OI-122 genes (set/ent, nleB, and nleE) and genes with other locations (lpfA, paa, ehxA, and ureD) were also associated with diarrheal disease. The phylogenetic marker gene yjaA was negatively associated with diarrhea (P = 0.0004). Atypical EPEC strains could be classified in two main virulence groups based on their content of OI-122, lpfA, and yjaA genes. Among children with diarrhea, atypical EPEC isolates belonging to virulence group I (OI-122 and lpfA positive, yjaA negative) were the most common, while the majority of isolates from healthy children were classified as virulence group II strains (OI-122 negative, lpfA and yjaA positive; P < 0.001). In conclusion, using DNA microarray analysis to determine the virulence gene profile of atypical EPEC isolates, several genes were found to be significantly associated with diarrhea. Based on their composition of virulence genes, the majority of strains could be classified in two virulence groups, of which one was seen mainly in children with diarrhea.

Candidemia in Norway (1991 to 2003): results from a nationwide study.

A long-term, nationwide prospective candidemia study has been ongoing in Norway since 1991. All medical microbiological laboratories in the country have participated. During the period 1991 to 2003 a total of 1,393 episodes of candidemia occurred in 1,348 patients. The incidence of candidemia episodes per 100,000 inhabitants increased from approximately 2 episodes in the early 1990s to 3 episodes in 2001 to 2003. The average annual incidences varied markedly between the age groups. The incidence was high in patients aged < 1 year and in patients aged > or = 70 years. In patients > or = 80 years of age, the incidence has increased during the last 3 years from an annual average of 6.5 to 15.6 cases/100,000 inhabitants in 2003. Four Candida species (C. albicans [70%], C. glabrata [13%], C. tropicalis [7%], and C. parapsilosis [6%]) accounted for 95.5% of the isolates. The species distribution has been constant during the 13-year study period. The distribution of the most important species varied with the age of the patient. In patients < 1 year of age, the majority of episodes were caused by C. albicans (91%). The occurrence of C. glabrata increased with age. In patients > or = 80 years of age, approximately 1/3 of all episodes were due to this species. All C. albicans strains were susceptible to fluconazole. The percentage of yeast isolates with decreased susceptibility to fluconazole (MICs > or = 16 microg/ml) was 10.7% during the first period of this study (1991 to 1996) and 11.7% during the second period (1997 to 2003).

Gastric bypass surgery does not increase susceptibility to Helicobacter pylori infection in the stomach of rat or mouse.

Gastric bypass is a clinical option for obesity surgery. An increased susceptibility to Helicobacter pylori infection in the bypassed stomach has been speculated. The aim of the present study was to examine the susceptibility of the bypassed stomach to H. pylori infection in rats and mice. Adult Sprague-Dawley and Wistar rats and NMRI mice were subjected to either gastric bypass or laparotomy only as control. The animals were inoculated with the CagA- and VacA- positive H. pylori strain 67/21 (not mouse-adapted) in the first experiment and with 9 additional isolates in the second, by injection into the bypassed stomach or the control stomach during surgery. The stomach of each animal was collected for H. pylori culture 2-3 weeks later. While all the rats were H. pylori negative, 54% of gastric bypassed mice and 75% of controls were positive (P = 0.4). We conclude that susceptibility to H. pylori infection in the stomach is not increased by gastric bypass surgery.

Immunological markers of the R4 protein of Streptococcus agalactiae.

This study focuses on immunological markers of R4, an important Streptococcus group B (GBS) protein. The results obtained by using rabbit antisera and purified proteins for antigens in enzyme-linked immunosorbent assay-based experiments provided evidence that R4 possesses two antigenic determinants. One of the determinants is shared with the alpha-like protein 3 (Alp3) of GBS, was named R4/Alp3 common, and was expressed by GBS, which possessed the Alp3-encoding gene alp3 or the R4-encoding gene rib. The other antigenic determinant was detected only in rib-positive GBS organisms and was named R4 specific. This determinant probably is an immunological marker unique to the R4 protein. Neither of the antigenic R4 determinants showed serological cross-reactivity with the GBS proteins Calpha, Cbeta, and R3 or with alpha-like protein 2. Of 60 clinical serotype III GBS strains, 56 (93%) isolates possessed the rib gene and 50 (89%) of the rib-positive isolates expressed levels of R4 detectable by antibody-based tests, consistent with R4 expression failure or low-level expression in approximately 10% of rib-positive GBS. alp3 was not detected in type III GBS but was possessed by six of eight type V strains and six of six type VIII strains. All alp3-positive strains were recognized by the R4/Alp3 common antibodies, but none of them were recognized by the R4-specific antibodies. NCTC 9828, a reference strain for R3 and R4, expressed the determinant R4/Alp3 common but not R4 specific. A monoclonal R4 antibody, previously considered to be R4 specific and used in GBS serotyping, targeted R4/Alp3 common and is thus not R4 specific. The results show that failure to discriminate between R4 specific and R4/Alp3 common by antisera designed for GBS serotyping can result in the false identification of Alp3 as R4 or vice versa, whereas anti-R4 antibodies targeting only the determinant R4 specific will detect only R4. Both R4 and Alp3 need further evaluation with respect to the immunobiological function of each distinct antigenic determinant, for instance, with regard to their potential as GBS vaccine components.

Antigenic determinants of alpha-like proteins of Streptococcus agalactiae.

The majority of group B streptococcus (GBS) isolates express one or more of a family of surface-anchored proteins that vary by strain and that form ladder-like patterns on Western blotting due to large repeat units. These proteins, which are important as GBS serotype markers and as inducers of protective antibodies, include the alpha C (Calpha) and R4 proteins and the recently described alpha-like protein 2 (Alp2), encoded by alp2, and Alp3, encoded by alp3. In this study, we examined antigenic determinants possessed by Alp2 and Alp3 by testing of antibodies raised in rabbits, mainly by using enzyme-linked immunosorbent assays (ELISA) and an ELISA absorption test. The results showed that Alp2 and Alp3 shared an antigenic determinant, which may be a unique immunological marker of the Alp variants of GBS proteins. Alp2, in addition, possessed an antigenic determinant which showed specificity for Alp2 and a third determinant which showed serological cross-reactivity with Calpha. Alp3, in addition to the determinant common to Alp2 and Alp3, harbored an antigenic site which also was present in the R4 protein, whereas no Alp3-specific antigenic site was detected. These ELISA-based results were confirmed by Western blotting and a fluorescent-antibody test. The results are consistent with highly complex antigenic structures of the alpha-like proteins in a fashion which is in agreement with the recently described structural mosaicism of the alp2 and alp3 genes. The results are expected to influence GBS serotyping, immunoprotection studies, and GBS vaccine developments.

Association of atypical enteropathogenic Escherichia coli (EPEC) with prolonged diarrhoea.

The aim of the present case control study was to investigate the prevalence of atypical enteropathogenic Escherichia coli (EPEC) and its possible role in causing diarrhoea among children < 5 years of age in Norway. Stool specimens received in the laboratory from children with suspected gastroenteritis (n = 251) were, in addition to routine testing, analysed for the presence of EPEC by PCR of the eae, bfpA and stx genes. Specimens from healthy children (n = 210) recruited from Maternal and Child Health Centres were analysed for EPEC only. EPEC isolates (eae+, stx-) were classified as typical (bfpA+) or atypical (bfpA-), and were tested for O : K serogroup. Information on duration of diarrhoea was recorded in a questionnaire and from referral forms. Atypical EPEC was diagnosed in 37 patients (14.7 %) compared to 21 (10.0 %) of the healthy controls [Odds ratio (OR) = 1.4, P = 0.3]. Only three isolates, all from patients, belonged to EPEC serogroups. One patient had typical EPEC. Twenty (22.5 %) of 89 patients with diarrhoea lasting > or = 14 days had atypical EPEC. The association between atypical EPEC and prolonged diarrhoea (OR = 2.1, P = 0.04) was caused by a high prevalence among female patients (40.6 %). In conclusion, atypical EPEC was found to be slightly more prevalent in patients than controls, without any overall significant association with diarrhoea. However, a significant association was observed with diarrhoea lasting 14 days or more, a finding that may indicate a role for atypical EPEC in prolonged disease.

Distribution of PFGE types of invasive Norwegian group B streptococci in relation to serotypes.

BACKGROUND & OBJECTIVES: Pulsed-field gel electrophoresis (PFGE) has been used for characterisation of group B streptococci, non-typeable by serotyping. We wanted to compare PFGE with serotyping in order to see the how well the method discriminates between epidemiological unrelated strains. METHODS: A total of 78 epidemiological unrelated invasive GBS strains were examined by PFGE using SmaI digested chromosomal DNA. Of these, 11 were nontypeable (NT) with regard to capsular polysaccharide (CPS) serotype. PFGE patterns were analyzed and classified in a dendrogram. RESULTS: 75 strains were typeable by PFGE, and a total of 62 restriction profiles were identified. At an 85 per cent similarity level, 53 different PFGE patterns were identified. Within each serotype, PFGE patterns differed considerably, the largest degree of heterogeneity observed among type IV, Ia, and II strains. Serotype Ib, III, and V strains were more homogeneous. Strains with identical macrorestriction profiles belonged to the same CPS type, but varied with regard to serosubtypes. Any strain among the ones investigated showing a greater than 88 per cent similarity to a restriction profile in the database, could correctly be ascribed to a particular CPS type. Of the 11 NT strains 10 restriction profiles were found, two of which were identical to the PFGE profile for a cluster of type V strains, and one profile were identical to the profile showed by a cluster of 5 type Ib strains. INTERPRETATION & CONCLUSION: PFGE is a useful technique for classifying strains that are non-typeable by conventional serotyping.

Susceptibility to quinupristin-dalfopristin and linezolid in 839 clinical isolates of Gram-positive cocci from Norway.

A total of 839 clinical isolates of Gram-positive cocci from Norway including Staphylococcus aureus (n = 214), coagulase negative Staphylococcus spp. (n = 100), Streptococcus pyogenes (n = 99), Streptococcus agalactiae (n = 80), Streptococcus pneumoniae (n = 127), Streptococcus spp. viridans group (n = 70), Enterococcus faecalis (n = 75), and Enterococcus faecium (n = 74), were tested by E-test for susceptibility to a range of antimicrobials including the novel antibiotics quinupristin-dalfopristin and linezolid. Subgroups of oxacillin resistant S. aureus and coagulase negative Staphylococcus spp., penicillin non-susceptible S. pneumoniae and vancomycin resistant Enterococcus spp. were specifically included as they are the intended targets for these new drugs. All isolates were susceptible to linezolid (MIC5o and MIC9o 0.25-2.0 mg/l, MIC range 0.12-2 mg/l). Staphylococcal and streptococcal isolates were also susceptible to quinupristin-dalfopristin except for some intermediately susceptible viridans group isolates (MIC54, and MIC90 0.25-2 mg/l, MIC range 0.125-2 mg/l). Enterococcus faecium (MIC90 = 4.0 mg/l) and Enterococcus faecalis (MIC50 = 8.0 mg/l, MIC90 > or = 32 mg/l) were less susceptible to this substance. There was no linkage between reduced susceptibility to linezolid or quinupristin-dalfopristin and resistance to other classes of antimicrobials. The study demonstrated a high prevalence of in vitro susceptibility to linezolid and quinupristin-dalfopristin, which is necessary for their use in the treatment of infections with resistant Gram-positive pathogens. The results were used to evaluate the appropriateness of breakpoints and to define a baseline for monitoring possible future emergence of resistance to quinupristin-dalfopristin and linezolid in Norway.

High prevalence of atypical enteropathogenic Escherichia coli (EPEC) in Norwegian children with diarrhoea.

The aim of the present study was to investigate the relative contribution of enteropathogenic Escherichia coli (EPEC) as a cause of infectious diarrhoea in Norwegian children. Data from faecal specimens from children <2 years old with diarrhoea during the year 2001 were analysed. E. coli isolates with the attaching and effacing genotype (eae+) were examined for the presence of the bundle-forming pilus (bfpA) and Shiga toxin genes by PCR, and for genetic relatedness by PFGE. During the 1-year period, 598 specimens from 440 patients <2 years old were analysed. Potential enteric pathogens were identified in 124 patients (28.2 %). EPEC was the most frequently identified agent (44 patients), followed by rotavirus (41 patients), Campylobacter jejuni (17 patients) and adenovirus (17 patients). All other agents were detected in five patients or less. Only one of the eae+ E. coli isolates was classified as typical EPEC (bfpA+). Among the 43 isolates that were classified as atypical EPEC (bfpA-), eight strains belonged to EPEC serogroups, whereas the majority of strains (n = 35) were not agglutinated by EPEC antisera. None of the EPEC isolates were genetically related. This study demonstrates that atypical EPEC of non-EPEC serogroups is highly prevalent among Norwegian children with diarrhoea.

Factors associated with increased and decreased risk of Campylobacter infection: a prospective case-control study in Norway.

In 1999-2000, a prospective case-control study of sporadic, domestically acquired campylobacteriosis was conducted in three counties in Norway to identify preventable risk factors and potentially protective factors. A total of 212 cases and 422 population controls matched by age, sex, and geographic area were enrolled. In conditional logistic regression analysis, the following factors were found to be independently associated with an increased risk of Campylobacter infection: drinking undisinfected water, eating at barbecues, eating poultry bought raw, having occupational exposure to animals, and eating undercooked pork. The following factors were independently related to a decreased risk: eating mutton, eating raw fruits or berries, and swimming. Results indicated that infection is more likely to occur as a result of cross-contamination from raw poultry products than because of poultry consumption per se. Drinking undisinfected water, reported by 53% of cases, was a leading risk factor in this study. Drinking water may constitute the common reservoir linking infection in humans and animals, including poultry and wild birds. Insight into the ecology of Campylobacter in freshwater ecosystems may be required to understand the epidemiology of campylobacteriosis. The possibility that certain foods confer protection against campylobacteriosis deserves exploration.

Posttrabeculectomy endophthalmitis caused by Moraxella nonliquefaciens.

Moraxella nonliquefaciens, a commensal organism of the upper respiratory tract, is generally considered to have low pathogenic potential. We report here two cases of severe endophthalmitis occurring 9 years and 2 months after glaucoma filtration surgery, respectively. Apart from sulfonamide, very low MICs were recorded for several antibiotics tested. Identification was based on phenotypic characteristics in combination with sequencing of the 16S rRNA gene.