Astrid Louise Wester

Age-related differences in symptoms, diagnosis and prognosis of bacteremia.

BackgroundElderly patients are at particular risk for bacteremia and sepsis. Atypicalpresentation may complicate the diagnosis. We studied patients withbacteremia, in order to assess possible age-related effects on the clinicalpresentation and course of severe infections.MethodsWe reviewed the records of 680 patients hospitalized between 1994 and 2004.All patients were diagnosed with bacteremia, 450 caused by Escherichiacoli and 230 by Streptococcus pneumoniae. Descriptiveanalyses were performed for three age groups (< 65 years,65–84 years, ≥ 85 years). In multivariate analyses age wasdichotomized (< 65, ≥ 65 years). Symptoms werecategorized into atypical or typical. Prognostic sensitivity of CRP and SIRSin identifying early organ failure was studied at different cut-off values.Outcome variables were organ failure within one day after admission andin-hospital mortality.ResultsThe higher age-groups more often presented atypical symptoms (p <0.001),decline in general health (p=0.029), and higher in-hospital mortality(p<0.001). The prognostic sensitivity of CRP did not differ between agegroups, but in those ≥ 85 years the prognostic sensitivity oftwo SIRS criteria was lower than that of three criteria. Classical symptomswere protective for early organ failure (OR 0.67, 95% CI 0.45-0.99), andrisk factors included; age ≥ 65 years (OR 1.65, 95% CI1.09-2.49), comorbid illnesses (OR 1.19, 95% CI 1.02-1.40 per diagnosis),decline in general health (OR 2.28, 95% CI 1.58-3.27), tachycardia (OR 1.50,95% CI 1.02-2.20), tachypnea (OR 3.86, 95% CI 2.64-5.66), and leukopenia (OR4.16, 95% CI 1.59-10.91). Fever was protective for in-hospital mortality (OR0.46, 95% CI 0.24-0.89), and risk factors included; age ≥ 65years (OR 15.02, 95% CI 3.68-61.29), ≥ 1 comorbid illness (OR2.61, 95% CI 1.11-6.14), bacteremia caused by S.pneumoniae (OR 2.79, 95% CI 1.43-5.46), leukopenia (OR 4.62,95% CI 1.88-11.37), and number of early failing organs (OR 3.06, 95% CI2.20-4.27 per failing organ).ConclusionsElderly patients with bacteremia more often present with atypical symptomsand reduced general health. The SIRS-criteria have poorer sensitivity foridentifying organ failure in these patients. Advanced age, comorbidity,decline in general health, pneumococcal infection, and absence of classicalsymptoms are markers of a poor prognosis.

Yersinia enterocolitica Outbreak Associated with Ready-to-Eat Salad Mix, Norway, 2011

In 2011, an outbreak of illness caused by Yersinia enterocolitica O:9 in Norway was linked to ready-to-eat salad mix, an unusual vehicle for this pathogen. The outbreak illustrates the need to characterize isolates of this organism, and reinforces the need for international traceback mechanisms for fresh produce.

Shiga Toxin 2a in Escherichia albertii

E scherichia albertii is an emerging human enteric pathogen ([1][1]). It belongs to the attaching and effacing group of bacteria, which also includes enteropathogenic and Shiga toxin-producing Escherichia coli (EPEC and STEC, respectively). Shiga toxin-producing E. albertii has been described,

Is the concentration of C-reactive protein in bacteraemia associated with age?

BackgroundC-reactive protein (CRP) is an indicator of inflammation, and is often used in the diagnosis of bacterial infections. It is poorly known whether CRP in bacterial infection is age-dependent.MethodsAdult patients with a positive blood culture with E. coli or S. pneumoniae during 1994–2004 were included. CRP measured on the same date as the blood cultures were drawn (CRP1), 2–3 days (CRP2) and 4–7 days later (CRP3), were retrieved. The patients were divided into three age groups, < 65, 65–84, and ≥ 85, respectively. We studied three cut-off values for CRP and produced age-specific receiver operating characteristics (ROC) curves, using patients with acute coronary or cerebral infarction as controls.Results890 patients and 421 controls were available. There was a statistically significant negative correlation between age and CRP1 – 0.072 (p = 0.032). The median CRP1 and CRP2 were significantly higher in the youngest age group. The area under the ROC-curve for the youngest age group was significantly greater than that of the two other age groups, but we found no statistically significant differences in sensitivity related to age. The diagnostic sensitivity of CRP was better for S. pneumoniae than for E. coli, 92.6% vs. 88.0% (p = 0.046) for a cut-off value of 40 mg/L, and 82.4% vs. 61.5% (p =< 0.01) for a cut-off value of 120 mg/L.ConclusionCRP is better in identifying infection with S. pneumoniae than with E. coli. We found a weakening of the CRP-response with age, but this is hardly of clinical significance.

National outbreak of Yersinia enterocolitica infections in military and civilian populations associated with consumption of mixed salad, Norway, 2014

In May 2014, a cluster of Yersinia enterocolitica (YE) O9 infections was reported from a military base in northern Norway. Concurrently, an increase in YE infections in civilians was observed in the Norwegian Surveillance System for Communicable Diseases. We investigated to ascertain the extent of the outbreak and identify the source in order to implement control measures. A case was defined as a person with laboratory-confirmed YE O9 infection with the outbreak multilocus variable-number tandem repeat analysis (MLVA)-profile (5-6-9-8-9-9). We conducted a case–control study in the military setting and calculated odds ratios (OR) using logistic regression. Traceback investigations were conducted to identify common suppliers and products in commercial kitchens frequented by cases. By 28 May, we identified 133 cases, of which 117 were linked to four military bases and 16 were civilians from geographically dispersed counties. Among foods consumed by cases, multivariable analysis pointed to mixed salad as a potential source of illness (OR 10.26; 95% confidence interval (CI): 0.85–123.57). The four military bases and cafeterias visited by 14/16 civilian cases received iceberg lettuce or radicchio rosso from the same supplier. Secondary transmission cannot be eliminated as a source of infection in the military camps. The most likely source of the outbreak was salad mix containing imported radicchio rosso, due to its long shelf life. This outbreak is a reminder that fresh produce should not be discounted as a vehicle in prolonged outbreaks and that improvements are still required in the production and processing of fresh salad products.

New-Onset Atrial Fibrillation in Bacteremia Is Not Associated with C-Reactive Protein, but Is an Indicator of Increased Mortality during Hospitalization

Background: Several studies have associated elevated C-reactive protein (CRP) levels to the occurrence of atrial fibrillation (AF). We sought to estimate the frequency and prognostic impact of AF in patients with bacteremia, and to study the possible association between AF and CRP as well as between AF and mortality in this population. Methods: We retrospectively evaluated patient charts of patients with bacteremia with Escherichia coli or Streptococcus pneumoniae admitted to the Aker University Hospital in Oslo between 1994 and 2004. Known cardiac risk factors for AF, signs and mode of conversion of AF, and, if applicable, date of death were registered, as were characteristics of infection, such as systemic inflammatory response syndrome and white blood cell count. Initial CRP values were categorized into 4 strata. Odds ratios of the 3 highest CRP categories compared with the lowest were obtained from logistic models adjusting for known cardiac risk factors for AF as well as possible factors that may have had an impact on the odds ratios for the different CRP levels. Cox regression analysis was used to compare new-onset AF and death during the first 2 weeks after hospitalization. Results: A total of 672 patient charts were studied; 104 patients (15.4%) had new-onset AF. Peak incidence of new-onset AF occurred on the day of admission. Peak CRP values were reached during the following 2 days. High CRP level at admission did not predict the occurrence of AF. The observed mortality was higher among patients with new-onset AF (p = 0.001) during the first 2 weeks after hospitalization, but this effect disappears when adjusted for relevant factors. Conclusions: The frequency of new-onset AF in bacteremia is substantial. Initial CRP levels or white blood cell count do not seem to predict new-onset AF, as opposed to systemic inflammatory response syndrome. On the other hand, in patients with bacteremia, new-onset AF should be viewed as an indicator of increased mortality and morbidity.

Evaluation of the ability of four ESBL-screening media to detect ESBL-producing Salmonella and Shigella

BackgroundThe aim of this study was to compare the ability of four commercially available media for screening extended-spectrum beta-lactamase (ESBL) to detect and identify ESBL-producing Salmonella and Shigella in fecal samples.A total of 71 Salmonella- and 21 Shigella- isolates producing ESBLA and/or AmpC, were received at Norwegian Institute of Public Health between 2005 and 2012. The 92 isolates were mixed with fecal specimens and tested on four ESBL screening media; ChromID ESBL (BioMrieux), Brilliance ESBL (Oxoid), BLSE agar (AES Chemunex) and CHROMagar ESBL (CHROMagar). The BLSE agar is a biplate consisting of two different agars. Brilliance and CHROMagar are supposed to suppress growth of AmpC-producing bacteria while ChromID and BLSE agar are intended to detect both ESBLA and AmpC.ResultsThe total sensitivity (ESBLA+AmpC) with 95% confidence intervals after 24hours of incubation were as follows: ChromID: 95% (90.4-99.6), Brilliance: 93% (87.6-98.4), BLSE agar (Drigalski): 99% (96.9-100), BLSE agar (MacConkey): 99% (96.9-100) and CHROMagar: 85% (77.5-92.5). The BLSE agar identified Salmonella and Shigella isolates as lactose-negative. The other agars based on chromogenic technology displayed Salmonella and Shigella flexneri isolates with colorless colonies (as expected). Shigella sonnei produced pink colonies, similar to the morphology described for E. coli.ConclusionAll four agar media were reliable in screening fecal samples for ESBLA-producing Salmonella and Shigella. However, only ChromID and BLSE agar gave reliable detection of AmpC-producing isolates. Identification of different bacterial species based on colony colour alone was not accurate for any of the four agars.

Are ready-to-eat salads ready to eat? An outbreak of Salmonella Coeln linked to imported, mixed, pre-washed and bagged salad, Norway, November 2013.

We investigated a nationwide outbreak of Salmonella Coeln in Norway, including 26 cases identified between 20 October 2013 and 4 January 2014. We performed a matched case-control study, environmental investigation and detailed traceback of food purchases to identify the source of the outbreak. In the case-control study, cases were found to be more likely than controls to have consumed a ready-to-eat salad mix (matched odds ratio 20, 95% confidence interval 2·7-∞). By traceback of purchases one brand of ready-to-eat salad was indicated, but all environmental samples were negative for Salmonella. This outbreak underlines that pre-washed and bagged salads carry a risk of infection despite thorough cleaning procedures by the importer. To further reduce the risk of infection by consumption of ready-to-eat salads product quality should be ensured by importers. Outbreaks linked to salads reinforce the importance of implementation of appropriate food safety management systems, including good practices in lettuce production.

Genomic Dissection of Travel-Associated Extended-Spectrum-Beta-Lactamase-Producing Salmonella enterica Serovar Typhi Isolates Originating from the Philippines: a One-Off Occurrence or a Threat to Effective Treatment of Typhoid Fever?

ABSTRACT One unreported case of extended-spectrum-beta-lactamase (ESBL)-producing Salmonella enterica serovar Typhi was identified, whole-genome sequence typed, among other analyses, and compared to other available genomes of S. Typhi. The reported strain was similar to a previously published strain harboring bla SHV-12 from the Philippines and likely part of an undetected outbreak, the first of ESBL-producing S. Typhi.

A Shigella sonnei outbreak traced to imported basil - The importance of good typing tools and produce traceability systems, Norway, 2011

On 9 October 2011, the University Hospital of North Norway alerted the Norwegian Institute of Public Health (NIPH) about an increase in Shigella sonnei infections in Tromsø. The isolates had an identical ‘multilocus variable-number tandem repeat analysis’ (MLVA) profile. Most cases had consumed food provided by delicatessen X. On 14 October, new S. sonnei cases with the same MLVA-profile were reported from Sarpsborg, south-eastern Norway. An outbreak investigation was started to identify the source and prevent further cases. All laboratory-confirmed cases from both clusters were attempted to be interviewed. In addition, a cohort study was performed among the attendees of a banquet in Tromsø where food from delicatessen X had been served and where some people had reported being ill. A trace-back investigation was initiated. In total, 46 cases were confirmed (Tromsø= 42; Sarpsborg= 4). Having eaten basil pesto sauce or fish soup at the banquet in Tromsø were independent risk factors for disease. Basil pesto was the only common food item that had been consumed by confirmed cases occurring in Tromsø and Sarpsborg. The basil had been imported and delivered to both municipalities by the same supplier. No basil from the specific batch was left on the Norwegian market when it was identified as the likely source. As a result of the multidisciplinary investigation, which helped to identify the source, the Norwegian Food Safety Authority, together with NIPH, planned to develop recommendations for food providers on how to handle fresh plant produce prior to consumption.