In clinical staphylococci, the presence of the ica genes and biofilm formation are considered important for virulence. Biofilm formation may also be of importance for survival and virulence in food-related staphylococci. In the present work, staphylococci from the food industry were found to differ greatly in their abilities to form biofilms on polystyrene. A total of 7 and 21 of 144 food-related strains were found to be strong and weak biofilm formers, respectively. Glucose and sodium chloride stimulated biofilm formation. The biofilm-forming strains belonged to nine different coagulase-negative species of Staphylococcus. The icaA gene of the intercellular adhesion locus was detected by Southern blotting and hybridization in 38 of 67 food-related strains tested. The presence of icaA was positively correlated with strong biofilm formation. The icaA gene was partly sequenced for 22 food-related strains from nine different species of Staphylococcus, and their icaA genes were found to have DNA similarities to previously sequenced icaA genes of 69 to 100%. Northern blot analysis indicated that the expression of the ica genes was higher in strong biofilm formers than that seen with strains not forming biofilms. Biofilm formation on polystyrene was positively correlated with biofilm formation on stainless steel and with resistance to quaternary ammonium compounds, a group of disinfectants.

Samples of sewage influent from 40 sewage treatment works (STW) throughout Norway were examined for Cryptosporidium oocysts and Giardia duodenalis cysts. Both parasites were detected frequently (80% of STW were Cryptosporidium positive; 93% of STW were Giardia positive) and at maximum concentrations of >20,000 parasites/liter. The data suggest giardiasis is more widespread, and/or occurs with greater infection intensity, than cryptosporidiosis in Norway. STW serving higher person equivalents were more likely to be positive and had higher parasite concentrations. Parasite concentrations were used to estimate the proportion of contributing populations that could be clinically infected. For Cryptosporidium, the highest estimates were up to 5 per 100,000 individuals for two populations in eastern Norway. For Giardia, the highest estimate was 40 infected per 100,000 persons (approximately five times the usual national annual average) contributing to an STW in western Norway. As this population experienced a large waterborne giardiasis outbreak 6 months after sampling, it can be speculated that regular challenge with Giardia may occur here. Most Giardia isolates in sewage influent were assemblage A, although some assemblage B isolates were detected. There was substantial heterogeneity, but most samples contained isolates similar to genotype A3. Removal efficiencies at two STW with secondary treatment processes were estimated to be approximately 50% for Cryptosporidium and >80% for Giardia. An STW with minimal treatment had negligible removal of both parasites. Many STW in Norway have minimal treatment and discharge effluent into rivers and lakes, thus, risk of contamination of water courses by Cryptosporidium and Giardia is considerable. Analysis of sewage influent for Cryptosporidium oocysts andGiardia duodenalis cysts has been used in a variety of studies to further elucidate aspects of the epidemiology, both conventional and molecular, of these parasites in particular populations or geographic regions (1,20). Additionally, such analyses can be used as an indirect method of assessing the occurrence of these infections in human populations (12,17,18). This is particularly useful in situations where it is believed that the occurrence of these infections is underestimated.Investigation of the epidemiology of cryptosporidiosis and giardiasis in human populations in Norway is hampered by lack of submission of fecal samples to diagnostic laboratories. This may be due to low infection rates but is more probably due to lack of awareness of these infections among medical personnel. In the absence of such specimens, investigation of sewage influent for these parasites can provide a useful approach for collecting data on the extent of infection in different regions. However, the method for analyzing such samples must be chosen carefully; particulate debris, fats, and other contaminants from a range of sources mean that standard water analysis procedures are inappropriate. Minimizing sample manipulation procedures has previousl...

During the autumn and winter of 2004 and 2005, an extensive outbreak of waterborne giardiasis occurred in Bergen, Norway. Over 1,500 patients were diagnosed with giardiasis. Analysis of water from the implicated source revealed low numbers of Giardia cysts, but the initial contamination event probably occurred up to 10 weeks previously. While sewage leakage from a residential area is now considered to be the probable source of contamination, during the episode waste from one particular septic tank was thought to be a possible source. Genotyping of cysts from the septic tank demonstrated that they were assemblage A cysts, although the sequences were not identical to any previously published sequences. For the ␤-giardin gene, the closest published subgenotype was subgenotype A3; for the gdh gene, the closest published subgenotype was subgenotype A2. Genotyping of cysts from 21 patient samples revealed that they were assemblage B cysts; thus, the septic tank was unlikely to be the contamination source. Sequencing of the ␤-giardin and gdh genes from patient samples and a comparison of the sequences gave complex results. For the ␤-giardin gene, three isolates had sequences identical to subgenotype B3 sequences. However, other isolates had between one and four single-nucleotide polymorphisms (SNPs). For the gdh gene, none of the sequences were identical to the sequence published for subgenotype B3, and the sequences had between one and three SNPs. One isolate, which was identical to subgenotype B3 at the ␤-giardin gene, was more similar to subgenotype B2 at the gdh gene. Grouping the isolates on the basis of SNPs resulted in different groups for the two genes. The results are discussed in relation to giardiasis in Norway and to other Giardia genotyping studies.Human parasitic infections, although probably underdiagnosed, are considered to be rare in Norway. Giardiasis is a reportable infection, and the annual recorded occurrence is 300 to 400 cases (around 8 cases per 100,000 population) for the whole country (6).During the autumn and winter of 2004 and 2005, an extensive outbreak of waterborne giardiasis occurred in Bergen, Norway (Table 1). Over 1,500 patients were laboratory diagnosed with Giardia infection, although considerably more individuals had symptoms, and Giardia infections considered to be outbreak associated continued to be diagnosed until June 2005.This was the first outbreak of a waterborne parasitic disease recorded in Norway, and various details were published in a report by the local council and members of the Norwegian Food Safety Authority (10). Once the increase in giardiasis cases had been noted, geographic clustering of the cases rapidly made it apparent that the outbreak was probably waterborne, and a particular water source was implicated.The initial source of contamination of the water supply was obviously of concern and interest, not least to ensure that repeat contamination events did not occur. The final report (10) indicates that sewage leakage from a residential area with drainage towar...

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ABSTRACT:There are few genotyping studies of Giardia duodenalis isolates from cervid hosts, although a previous study suggested that cervids may be a source of infection for humans and cattle. Giardia duodenalis isolates collected from wild moose (Alces alces) and reindeer (Rangifer tarandus) in Norway during 2002 and 2003 were characterized by polymerase chain reactionrestriction fraction length polymorphism (PCR-RFLP) at the b-giardin gene, and sequence analysis at both the b-giardin and glutamate dehydrogenase (gdh) genes. All results suggested that these isolates (n525) belonged to assemblage A. Three different restriction patterns were obtained with PCR-RFLP, one of which has previously been associated with assemblage A. At the b-giardin gene, sequences from six reindeer isolates and one moose isolate were identical to a previously published assemblage A sequence from G. duodenalis cysts isolated from dairy calves. The other 10 moose isolates could be divided into five groups, with between two and 14 single nucleotide polymorphisms (SNPs) from the published genotype A2. At the gdh gene, three different sequences were obtained, differing from each other by between one and 15 SNPs and which have all been previously published as genotype A1, but with different specific hosts. Grouping of the isolates based on the sequences from both genes gave complex results; whereas all the G. duodenalis isolates from reindeer grouped together, two moose isolates, which had identical sequences at the b-giardin gene, had sequences that differed from each other by 15 SNPs at the gdh gene. The results of these studies, together with the large Norwegian populations of these cervids and the amount of fecal matter they produce, indicate that moose and reindeer may be significant reservoirs of G. duodenalis infection in Norway, which may be of importance to veterinary and public health.