A survey was conducted on the possible factors influencing exposure to mercury vapour during the handling of amalgam and amalgam contaminated products at dental clinics in Norrbotten, the northern part of Sweden, as well as the current methods being used to minimise, if not prevent such exposures. Increased room temperature, a serious problem when working with amalgam, was the most common complaint from the dental personnel reflecting the observation that ventilation in most clinics was far from being satisfactory. However, methods of treating amalgam-contaminated waste products as well as the classification of products as high- or low-risk wastes also differed a lot. The results further showed that although majority of the dental personnel showed concern on the possible hazards of mercury vapour exposure and were interested in having the level of mercury vapour measured in their clinics, very few had access to any protective equipment against it. And among the few who had some forms of protective wear, most found the equipment disturbing and disruptive of work performance.
On and shortly after the 6th May 1990, 16 people were affected by food poisoning in an old peoples' residential home, of whom two died. The vehicle of infection was identified as a baked Alaska contaminated by Salmonella enteritidis phage type (PT) 8 and, at an early stage of the investigation, the source was attributed to a single infected egg. A separate investigation by the author, however, revealed that the baked Alaska meringue had been dispensed from an inadequately cleaned piping bag which had been recovered from the kitchen a month after the outbreak. A pure, profuse culture of S. enteritidis PT8 was isolated from it. At least one secondary case may have been attributable to food made with this bag. Ministry of Agriculture Investigations of the flocks suspected of producing the eggs used for the baked Alaska demonstrated an absence of S. enteritidis. On this basis, the author considered a more likely cause of the outbreak to be the piping bag, contaminated from source or sources unknown within the kitchen. Furthermore, the possibility of human carrier transmission cannot be wholly ruled out. The incident underlines the dangers of jumping to conclusions at the outset of food poisoning investigations and emphasises that hypotheses formulated on sources of contamination must be properly tested, the absence of which, in this instance, led the investigators to unwarranted conclusions as to the cause of the outbreak.
During the winter of 2000 to 2001, an outbreak due to Salmonella Enteritidis (SE) phage type 30 (PT30), a rare strain, was detected in Canada. The ensuing investigation involved Canadian and American public health and food regulatory agencies and an academic research laboratory. Enhanced laboratory surveillance, including phage typing and pulsed-field gel electrophoresis, was used to identify cases. Case questionnaires were administered to collect information about food and environmental exposures. A case-control study with 16 matched case-control pairs was conducted to test the hypothesis of an association between raw whole almond consumption and infection. Almond samples were collected from case homes, retail outlets, and the implicated processor, and environmental samples were collected from processing equipment and associated farms for microbiological testing. One hundred sixty-eight laboratory-confirmed cases of SE PT30 infection (157 in Canada, 11 in the United States) were identified between October 2000 and July 2001. The case-control study identified raw whole almonds as the source of infection (odds ration, 21.1; 95% confidence interval, 3.6 to infinity). SE PT30 was detected in raw whole natural almonds collected from home, retail, distribution, and warehouse sources and from environmental swabs of processing equipment and associated farmers' orchards. The frequent and prolonged recovery of this specific organism from a large agricultural area was an unexpected finding and may indicate significant diffuse contamination on these farms. Identification of almonds as the source of a foodborne outbreak is a previously undocumented finding, leading to a North American recall of this product and a review of current industry practices.
BACKGROUND: On 21 May 2005, the Norwegian health authorities were alerted by officials from a local hospital that several recent patients had received the diagnosis of legionnaires disease; all patients resided in 2 neighboring municipalities. We investigated the outbreak to identify the source and to implement control measures. METHODS: We interviewed all surviving case patients and investigated and harvested samples from 23 businesses with cooling towers and other potential infection sources. The locations of the businesses and the patients' residences and movements were mapped. We calculated attack rates and risk ratios among people living within various radii of each potential source. Isolates of Legionella pneumophila were compared using molecular methods. RESULTS: Among 56 case patients, 10 died. The case patients became ill 12-25 May, resided up to 20 km apart, and had not visited places in common. Those living up to 1 km from a particular air scrubber had the highest risk ratio, and only for this source did the risk ratio decrease as the radius widened. Genetically identical L. pneumophila serogroup 1 isolates were recovered from patients and the air scrubber. The air scrubber is an industrial pollution-control device that cleans air for dust particles by spraying with water. The circulating water had a high organic content, pH of 8-9, and temperature of 40 degrees C. The air was expelled at 20 m/s and contained a high amount of aerosolized water. CONCLUSIONS: The high velocity, large drift, and high humidity in the air scrubber may have contributed to the wide spread of Legionella species, probably for >10 km. The risk of Legionella spread from air scrubbers should be assessed.
To report a multi-institution outbreak caused by a single strain of methicillin-resistant Staphylococcus aureus (MRSA).
Between September 19 and November 20, 1996 an index case and five secondary cases of nosocomial MRSA occurred on a 26 bed adult plastic surgery/burn unit (PSBU) at a tertiary care teaching hospital. Between November 11 and December 23, 1996, six additional cases were identified at a community hospital. One of the community hospital cases was transferred from the PSBU. All strains were identical by pulsed-field gel electrophoresis. MRSA may have contributed to skin graft breakdown in one case, and delayed wound healing in others. Patients required 2 to 226 isolation days.
A hand held shower and stretcher for showering in the hydrotherapy room of the PSBU were culture positive for the outbreak strain, and the presumed means of transmission. Replacement of stretcher showering with bedside sterile burn wound compresses terminated the outbreak. The PSBU was closed to new admissions and transfers out for 11 days during the investigation. Seven of 12 patients had effective decolonization therapy.
Environmental contamination is a potential source of nosocomial MRSA transmission on a burn unit. Notification among institutions and community care providers of shared patients infected or colonized with an antimicrobial resistant microorganism is necessary.
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.
In October 1999, 7 patients with postoperative infections caused by Serratia marcescens were identified at a community hospital in Ontario, Canada. We describe the investigation of this outbreak.
We undertook a case-control study to determine risk factors associated with infection. Case subjects consisted of patients who had undergone surgery and acquired bacteremia or wound infections that, when cultured, grew S marcescens. Control subjects were selected from the cohort of patients who underwent surgery at the same hospital during the outbreak period. Chart reviews were conducted for case and control subjects. Environmental samples were taken from medications and liquids in the operating rooms and from one health care professional who was involved in all the cases. S marcescens isolates were forwarded to a reference laboratory for pulsed field gel electrophoresis.
We identified 7 case subjects and 29 control subjects. Five patients had bacteremia and 2 patients had wound infections. Two patients with bacteremia died. All patients with bacteremia or wound infections were exposed to a single anesthetist (anesthetist A) and were administered the anesthetic medication propofol. These patients were more than 40 times more likely to have had anesthetist A administer their anesthetic (OR 41.6, 95% CI 3.6-1120) and 22 times more likely to have received propofol (OR 22, 95% CI 2.1-550) than were control subjects. None of the environmental samples or cultures from anesthetist A were positive for S marcescens. Six of the 7 human isolates had an identical pulsed field gel electrophoresis pattern, and the seventh was untypable.
This outbreak of postoperative infections was very strongly linked to the use of propofol by one anesthetist. Health care professionals must follow strict aseptic techniques when using propofol and should review these techniques regularly.
Five in-patient and out-patient tuberculosis (TB) care facilities in two regions of Russia.
To identify barriers and motivators to the use of infection control measures among Russian TB health care workers.
In this qualitative study, a convenience sample of 96 health care workers (HCWs) was used to generate 15 homogeneous focus groups, consisting of physicians, nurses, and laboratory or support staff.
Barriers and motivators related to knowledge, attitudes and beliefs, and practices were identified. The three main barriers were 1) knowledge deficits, including the belief that TB was transmitted by dust, linens and eating utensils; 2) negative attitudes related to the discomfort of respirators; and 3) practices with respect to quality and care of respirators. Education and training, fear of infecting loved ones, and fear of punishment were the main motivators.
Our results point to the need for evaluation of current educational programs. Positive health promotion messages that appeal to fear might also be successful in promoting TB infection control. Individualized rewards based on personal motivators or group rewards that build on collectivist theory could be explored.
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We surveyed US and Canadian pediatric hospitals about their use of central line-associated bloodstream infection (CLABSI) prevention strategies beyond typical insertion and maintenance bundles. We found wide variation in supplemental strategies across hospitals and in their penetration within hospitals. Future studies should assess specific adjunctive prevention strategies and CLABSI rates.