Thøger Gorm Jensen

Species Identification of Clinical Isolates of Anaerobic Bacteria: a Comparison of Two Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Systems

ABSTRACT We compared two matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) systems (Shimadzu/SARAMIS and Bruker) on a collection of consecutive clinically important anaerobic bacteria (n = 290). The Bruker system had more correct identifications to the species level (67.2% versus 49.0%), but also more incorrect identifications (7.9% versus 1.4%). The system databases need to be optimized to increase identification levels. However, MALDI-TOF MS in its present version seems to be a fast and inexpensive method for identification of most clinically important anaerobic bacteria.

Increasing incidence of pyogenic spondylodiscitis: a 14-year population-based study.

OBJECTIVES Smaller studies indicate that the incidence of pyogenic spondylodiscitis is increasing, possible related to a growing elderly population. Data supporting this is sparse, and we therefore studied patient characteristics and changes in spondylodiscitis incidence 1995-2008. METHODS In a population-based study we identified all patients aged ≥18 years treated for pyogenic spondylodiscitis in Funen County, Denmark (population 483 123). Annual incidences were determined. Demographics, symptoms and diagnostic methods were recorded. RESULTS We found 192 cases: median age 66.6 years; 57.3% men; 76.6% culture positive cases. Staphylococcus aureus was the most common pathogen (55.1%). During 1995-2008 the overall incidence, incidence of culture negative cases, and incidence of cases due to S. aureus increased 2.2-5.8, 0.3-1.8, and 1.6-2.5 cases per 100 000 person years, respectively. The elderly had the highest incidence compared to those aged ≤70 years (rate ratio for men 5.9 (95% CI: 4.2-8.5) and for women 3.5 (95% CI: 2.3-5.3)). CONCLUSIONS During 1995-2008 the overall incidence of S. aureus and culture negative cases of spondylodiscitis increased and remained highest among the elderly. Whether the increase is real or is a result of improved diagnostic methods and workup remains unknown.

Emergence of ampicillin-resistant Enterococcus faecium in Danish hospitals

BACKGROUND Ampicillin-resistant Enterococcus faecium isolates are reported in increasing numbers in many European hospitals. The clonal complex 17 (CC17) characterized by ampicillin resistance has been associated with nosocomial E. faecium outbreaks and infections in five continents. The aim was to investigate how prevalent ampicillin resistance is in clinical E. faecium isolates from Denmark and to investigate their clonal affiliation, especially to CC17. METHODS Microbiology data from 2002 through 2006 on E. faecium and Enterococcus faecalis blood isolates was received from Departments of Clinical Microbiology in 11 Danish counties. From January 2004 through December 2004, we collected 275 clinical enterococci from four of these departments. Multilocus sequence typing (MLST) and PFGE were performed on the 84 ampicillin-resistant E. faecium isolates from this collection. RESULTS A 68% increase in the number of infections caused by enterococci was observed from 2002 through 2006. The increase was mainly caused by E. faecium isolates, which tripled, whereas the number of E. faecalis isolates increased by only 23% during the same period. There was also a significant increase in the number of ampicillin-resistant E. faecium isolates. MLST showed that 98% of the tested ampicillin-resistant E. faecium isolates belonged to CC17. PFGE showed eight different clusters and we found indications of clonal spread within the hospitals. CONCLUSIONS Ampicillin-resistant E. faecium isolates have increased in frequency in Denmark during 2002-2006. Most of the ampicillin-resistant E. faecium isolates belong to complex CC17.

Performance of matrix-assisted laser desorption-time of flight mass spectrometry for identification of clinical yeast isolates

Accurate and fast yeast identification is important when treating patients with invasive fungal disease as susceptibility to antifungal agents is highly species related. Matrix‐assisted laser desorption‐time of flight mass spectrometry (MALDI‐TOF‐MS) provides a powerful tool with a clear potential to improve current diagnostic practice. Two MALDI‐TOF‐MS‐systems (BioTyper/Bruker and Saramis/AXIMA) were evaluated using: (i) A collection of 102 archived, well characterised yeast isolates representing 14 different species and (ii) Prospectively collected isolates obtained from clinical samples at two participating laboratories. Of the 102 archived isolates, 81 (79%) and 92 (90%) were correctly identified by Saramis/AXIMA and BioTyper/Bruker respectively. Saramis/AXIMA was unable to separate Candida albicans, C. africana and C. dubliniensis in 13 of 32 isolates. After manual interpretation of the mass spectra output, all 13 isolates were correctly identified, resulting in an overall identification performance of 92%. No misidentifications occurred with the two systems. Of the routine isolates one laboratory identified 99/99 (100%) and 90/99 (91%) to species level by Saramis/Axima and conventional identification, respectively, whereas the other laboratory identified 83/98 (85%) to species level by both BioTyper/Bruker and conventional identification. Both MALDI‐TOF‐MS systems are fast, have built‐in databases that cover the majority of clinically relevant Candida species, and have an accuracy that outperforms our conventional identification systems.

Incidence rate of community-acquired sepsis among hospitalized acute medical patients-a population-based survey.

Objective:Sepsis is a frequent cause of admission, but incidence rates based on administrative data have previously produced large differences in estimates. The aim of the study was to estimate the incidence of community-acquired sepsis based on patients’ symptoms and clinical findings at arrival to the hospital. Design:Population-based survey. Setting:Medical emergency department from September 1, 2010, to August 31, 2011. Patients:All patients were manually reviewed using a structured protocol in order to identify the presence of infection. Vital signs and laboratory values were collected to define the presence of systemic inflammatory response syndrome and organ dysfunction. Measurements and Main Results:Incidence rate of sepsis of any severity. Among 8,358 admissions to the medical emergency department, 1,713 patients presented with an incident admission of sepsis of any severity, median age 72 years (5–95%; range, 26–91 yr), 793 (46.3%) were men, 728 (42.5%) presented with a Charlson comorbidity index greater than 2,621 (36.3%) were admitted with sepsis, 1,071 (62.5%) with severe sepsis, and 21 (1.2%) with septic shock. Incidence rate was 731/100,000 person-years at risk (95% CI, 697–767) in patients with sepsis of any severity, 265/100,000 person-years at risk (95% CI, 245–287) in patients with sepsis, 457/100,000 person-years at risk (95% CI, 430–485) in patients with severe sepsis, and 9/100,000 person-years at risk (95% CI, 6–14) in patients with septic shock. Conclusions:Based on symptoms and clinical findings at arrival, incidence rates of patients admitted to a medical emergency department with sepsis and severe sepsis are more frequent than previously reported based on discharge diagnoses.

Decreasing incidence rates of bacteremia: A 9-year population-based study

BACKGROUND Numerous studies have shown that the incidence rate of bacteremia has been increasing over time. However, few studies have distinguished between community-acquired, healthcare-associated and nosocomial bacteremia. METHODS We conducted a population-based study among adults with first-time bacteremia in Funen County, Denmark, during 2000-2008 (N = 7786). We reported mean and annual incidence rates (per 100,000 person-years), overall and by place of acquisition. Trends were estimated using a Poisson regression model. RESULTS The overall incidence rate was 215.7, including 99.0 for community-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. During 2000-2008, the overall incidence rate decreased by 23.3% from 254.1 to 198.8 (3.3% annually, p < .001), the incidence rate of community-acquired bacteremia decreased by 25.6% from 119.0 to 93.8 (3.7% annually, p < .001) and the incidence rate of nosocomial bacteremia decreased by 28.9% from 82.2 to 56.0 (4.2% annually, p < .001). The incidence rate of healthcare-associated bacteremia remained stable. The most common microorganisms were Escherichia coli (28.3%), Staphylococcus aureus (12.3%), coagulase-negative staphylococci (10.0%) and Streptococcus pneumoniae (9.1%). Regardless of place of acquisition, the proportion of bacteremias caused by enterococci increased (p < .05) and the proportion caused by coagulase-negative staphylococci decreased (p < .05). CONCLUSIONS The incidence rates of community-acquired and nosocomial bacteremia decreased substantially over time.

Increased short- and long-term mortality among patients with infectious spondylodiscitis compared with a reference population

BACKGROUND CONTEXT Information on short- and especially long-term mortality among patients with infectious spondylodiscitis is sparse. PURPOSE To analyze mortality, factors associated with death, and cause-specific mortality rates among patients with infectious nonpostoperative spondylodiscitis. STUDY DESIGN A case-cohort study. PATIENT SAMPLE We identified all patients aged 18 years or older treated for infectious spondylodiscitis from January 1994 to May 2009 at hospitals in Funen County, Denmark. OUTCOME MEASURES Overall and cause-specific mortality. METHODS Mortality rates among patients were compared with rates among a reference population using Kaplan-Meier plots and mortality rate ratios (MRRs). Short-term mortality was defined as deaths within first year after admission and long-term mortality was deaths thereafter. Factors associated with death were determined. RESULTS Among 298 identified patients, 61 (20%) died within the first year. Adjusted MRRs were 16.8 (95% confidence interval: 9.9-28.5) for 0 to 90 days; 4.2 (2.5-7.0) for 91 to 365 days; 2.2 (1.6-2.9) for 1 to 4 years; and 1.7 (1.2-2.5) for 5 to 14 years. Mortality rate ratios stratified on microbiological etiology were 8.8 (3.3-22.1) for 0 to 90 days; 1.4 (0.3-5.8) for 91 to 365 days; 3.2 (2.0-5.1) for 1 to 4 years; and 1.1 (0.5-2.4) for 5 to 14 years for unknown etiology and 24.0 (13.0-44.2) for 0 to 90 days; 6.0 (3.1-11.5) for 91 to 365 days; 1.9 (1.1-3.2) for 1 to 4 years; and 2.7 (1.5-4.7) for 5 to 14 years among Staphylococcus aureus infections. The main factors associated with short-term mortality were severe neurologic deficits at the time of admission, epidural abscess, and comorbidities. Long-term mortality seemed independent of microbiological etiology. CONCLUSIONS Mortality remained high the first year after admission and thereafter decreased with time to a level close to the reference population. Short-term mortality was especially related to infection with abscess formation and neurologic deficits and long-term mortality was related to alcohol dependency.

Risk Factors for Hospitalization Due to Community-Acquired Sepsis – A Population-Based Case-Control Study

Background The aim of the study was to estimate risk factors for hospitalization due to sepsis and to determine whether these risk factors vary by age and gender. Methods We performed a population-based case-control study of all adult patients admitted to a medical ED from September 2010 to August 2011. Controls were sampled within the hospital catchment-area. All potential cases were manually validated using a structured protocol. Vital signs and laboratory values measured at arrival were registered to define systemic inflammatory response syndrome and organ dysfunction. Multivariable logistic regression was used to elucidate which predefined risk factors were associated with an increased or decreased risk hospitalization due to sepsis. Results A total of 1713 patients were admitted with sepsis of any severity. The median age was 72 years (interquartile range: 57–81 years) and 793 (46.3%) were male. 621 (36.3%) patients were admitted with sepsis, 1071 (62.5%) with severe sepsis and 21 (1.2%) with septic shock. Episodes with sepsis of any severity were associated with older age (85+ years adjusted OR 6.02 [95%CI: 5.09–7.12]), immunosuppression (4.41 [3.83–5.09]), alcoholism-related conditions (2.90 [2.41–3.50]), and certain comorbidities: psychotic disorder (1.90 [1.58–2.27]), neurological (1.98 [1.73–2.26]), respiratory (3.58 [3.16–4.06]), cardiovascular (1.62 [1.41–1.85]), diabetes (1.82 [1.57–2.12]), cancer (1.44 [1.22–1.68]), gastrointestinal (1.71 [1.44–2.05]) and renal (1.46 [1.13–1.89]). The strength of the observed associations for comorbid factors was strongest among younger individuals. Conclusions Hospitalization due to sepsis of any severity was associated with several independent risk factors, including age and comorbid factors.

Dysgonomonas capnocytophagoides bacteraemia in a neutropenic patient treated for acute myeloid leukaemia

Dysgonomonas capnocytophagoides, formerly known as CDC group DF‐3, is an opportunistic pathogen associated with diarrhoea and very rarely bacteraemia. We report a case of D. capnocytophagoides found in blood cultures from a severely neutropenic patient treated for acute myeloid leukaemia. The isolate was found resistant to penicillin, cephalosporins, meropenem, aminoglycosides and ciprofloxacin, and susceptible to ampicillin, tetracycline, chloramphenicol, clindamycin and trimethoprim‐sulphamethoxazole. It was identified using conventional phenotypic testing but remained unidentified by the automated identification system (Vitek‐2) as this system did not contain DF‐3 or D. capnocytophagoides in its database.

Does C-reactive protein independently predict mortality in adult community-acquired bacteremia patients with known sepsis severity?

We evaluated whether sepsis severity and C‐reactive protein (CRP) level on admission prognostically corroborated or annulled each other in adult patients with incident community‐acquired bacteremia (Funen, Denmark, 2000–2008). We used logistic regression and area under the receiver operating characteristic curve (AUC) to evaluate 30‐day mortality in four models: (i) age, gender, comorbidity, bacteria, and ward. (ii) Model 1 and sepsis severity. (iii) Model 1 and CRP. (iv) Model 1, sepsis severity, and CRP. Altogether, 416 of 1999 patients died within 30 days. CRP independently predicted 30‐day mortality [Model 4, odds ratio (95% CIs) for 100 mg/L: 1.16 (1.06–1.27)], but it did not contribute to the AUC (Model 2 vs Model 4: p = 0.31). In the 963 non‐severe sepsis patients, CRP independently predicted 30‐day mortality [Model 4: 1.42 (1.20–1.69)] and it increased the AUC (Model 2 vs Model 4: p = 0.06), thus CRP contributed as much as sepsis severity to prognosis.