Detection of methicillin-resistant Staphylococcus aureus sequence type 8 in pigs, production environment, and human beings.

Two follow-up studies of a positive methicillin-resistant Staphylococcus aureus (MRSA) finding in the 2008 European Union baseline survey on MRSA in pig herds were performed to gain more knowledge about the epidemiology of the particular MRSA type, a known human type (ST8/t008), among pigs. Two persons on a Norwegian farm in the study were found to be MRSA carriers, and human-to-animal transmission was suspected. In the first follow-up study, all pigs (n  =  346) were sampled by taking nasal swabs. A pooled sample from 5 individual pigs housed together in a single pen, and a dust sample from the equipment in the same room, were positive. Dust samples from a building housing MRSA-negative animals were negative. The MRSA was not detected in the second follow-up, after removing positive animals from the farm and cleaning and disinfecting. A low MRSA occurrence among the animals was found, suggesting that MRSA ST8/t008 may be less able to colonize and persist in pig holdings compared with more host-adapted S. aureus strains.

Pseudomonas aeruginosa contamination of mouth swabs during production causing a major outbreak.

BACKGROUND: In 2002 we investigated an outbreak comprising 231 patients in Norway, caused by Pseudomonas aeruginosa and linked to the use of contaminated mouth swabs called Dent-O-Sept. Here we describe the extent of contamination of the swabs, and identify critical points in the production process that made the contamination possible, in order to prevent future outbreaks. METHODS: Environmental investigation with microbiological examination of production, ingredients and product, molecular typing of bacteria and a system audit of production. RESULTS: Of the 1565 swabs examined from 149 different production batches the outbreak strain of P. aeruginosa was detected in 76 swabs from 12 batches produced in 2001 and 2002. In total more than 250 swabs were contaminated with one or more microbial species. P. aeruginosa was detected from different spots along the production line. The audit revealed serious breeches of production regulations. Health care institutions reported non-proper use of the swabs and weaknesses in their purchasing systems. CONCLUSION: Biofilm formation in the wet part of the production is the most plausible explanation for the continuous contamination of the swabs with P. aeruginosa over a period of at least 30 weeks. When not abiding to production regulations fatal consequences for the users may ensue. For the most vulnerable patient groups only documented quality-controlled, high-level disinfected products and items should be used in the oropharynx.

An outbreak of Pseudomonas aeruginosa infection caused by contaminated mouth swabs.

BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterium that can cause severe infection in susceptible patients. During the winter of 2001-2002, we investigated an outbreak of P. aeruginosa infection among patients in several hospitals across Norway. METHODS: A nationwide outbreak investigation was performed with case finding, questionnaires, and product sampling. All available clinical and environmental P. aeruginosa strains were genotyped. Detailed information was collected from patients with the outbreak strain or with any P. aeruginosa in blood or cerebrospinal fluid samples. To identify risk factors, we conducted a case-control study among patients with P. aeruginosa isolated from blood or cerebrospinal fluid samples during October 2001-December 2002. Case patients were patients infected with the outbreak genotype, and control subjects were patients infected with other genotypes. RESULTS: A total of 231 patients from 24 hospitals were identified as having the outbreak strain; 39 of these patients had positive blood culture results. Seventy-one patients (31%) died while hospitalized; all of the patients who died had severe underlying disease. Among 39 case patients and 159 control subjects, use of the moist mouth swab (adjusted odds ratio, 5.3; 95% confidence interval, 2.0-13.6) and receipt of mechanical ventilation (adjusted odds ratio, 6.4; 95% confidence interval, 2.3-17.2) were associated with infection due to the outbreak strain. Genotypically identical strains of P. aeruginosa were identified in 76 mouth swabs from 12 different batches and from the production line. CONCLUSIONS: Contamination of mouth swabs during production caused the largest-ever outbreak of P. aeruginosa infection in Norway. Susceptible patient groups should use only documented quality-controlled, high-level-disinfected products and items in the oropharynx.

[Legionella in Trondheim, Norway--determining sources of contagion and tracing risk environments]. / Legionella i Trondheim - smitteoppsporing og miljøkartlegging.

BACKGROUND: Legionnaires' disease, most often a serious condition, is a relatively rare disease in Norway although in recent years it has been on the increase. Because of clinical and microbiological diagnostic difficulties, one can assume that the number of new cases reported is significantly too low. MATERIAL AND METHOD: A multidisciplinary team established in the City of Trondheim has two main functions; first, to trace sources of contagion when outbreaks of the disease and detected; second, to carry out routine inspections in order to trace potential environmental sources. RESULTS: Over a four-year period (2001 - 2004), 19 cases of Legionnaires' disease were diagnosed; 17 of these are presumed to have originated locally. This is an incidence rate five times greater than the national average. Legionella pneumophila was discovered in the patients' local environment in 6 cases. Environmental investigations showed that the bacterium was present in three water-cooling towers, one Jacuzzi, one swimming pool, a shower in a factory, and in the hot-water system of a building complex. Most of the discoveries were made in the summer or autumn in several different locations in the city. Legionella pneumophila was found more often with low rather than high bacterial count, contrary to the information given in the Norwegian Legionnaires' disease prevention handbook. INTERPRETATION: Legionella pneumophila is in all likelihood a naturally occurring bacterium in many of the water sources and water supply plants in Trondheim. This requires continual awareness and readiness to tackle the disease. We have seen that a multidisciplinary team is well suited to evaluating high-risk environments, tracing outbreaks and carrying out information tasks targeted both at professionals and the public at large.