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Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants
Published on: May 4, 2018
An outbreak of Pseudomonas aeruginosa infection caused by contaminated mouth swabs
Bjørn G Iversen1, Trond Jacobsen, Hanne-Merete Eriksen
1Norwegian Institute of Public Health, Oslo, Norway. bjiv@fhi.no
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.
Insights
Contaminated mouth swabs caused a large Pseudomonas aeruginosa outbreak in Norway. This highlights the need for quality control in medical products to protect vulnerable patients from severe infections.
Area of Science:
- Infectious Disease Epidemiology
- Bacterial Pathogenesis
- Public Health Surveillance
Background:
- Opportunistic bacterial infections, such as those caused by Pseudomonas aeruginosa, pose significant risks to susceptible patient populations.
- A nationwide investigation was conducted in Norway during the 2001-2002 winter to address a P. aeruginosa infection outbreak across multiple hospitals.
Purpose of the Study:
- To investigate the cause and identify risk factors associated with a large-scale Pseudomonas aeruginosa outbreak in Norwegian hospitals.
- To determine the source of infection and implement measures to prevent future occurrences.
Main Methods:
- A nationwide outbreak investigation involved case finding, patient and product questionnaires, and extensive bacterial strain genotyping.
- A case-control study was conducted to identify risk factors, comparing patients infected with the outbreak strain to those with other P. aeruginosa genotypes.
- Clinical and environmental P. aeruginosa isolates were analyzed, alongside samples from mouth swabs and production lines.
Main Results:
- A total of 231 patients across 24 hospitals were identified with the outbreak strain, with 39 experiencing bloodstream infections.
- Mortality was high (31%), primarily among patients with severe underlying conditions.
- Key risk factors identified included the use of moist mouth swabs (aOR 5.3) and mechanical ventilation (aOR 6.4).
- Genotypically identical P. aeruginosa strains were found in mouth swabs and on the production line, indicating product contamination.
Conclusions:
- The largest P. aeruginosa outbreak in Norway was attributed to contamination of mouth swabs during the manufacturing process.
- It is crucial for susceptible patient groups to use only documented, quality-controlled, and high-level-disinfected oropharyngeal products.
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