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ABSTRACT: OBJECTIVES: Penicillin-susceptible Staphylococcus aureus isolates account for a fifth of cases of S. aureus bacteraemia (SAB) in Denmark, but little is known about treatment outcomes with penicillins or other antimicrobials. Here we compare penicillin, dicloxacillin and cefuroxime as definitive treatments in relation to 30 day mortality. METHODS: A retrospective chart review of 588 penicillin-susceptible S. aureus cases at five centres from January 1995 to December 2010. Data on demographics, antimicrobial treatment, clinical signs and symptoms, and mortality at day 30 were collected. Hazard ratios (HRs) with 95% CIs associated with mortality were modelled using propensity-score-adjusted Cox proportional hazards regression analysis. Propensity-score-matched case-control studies were carried out. RESULTS: Definitive therapy with cefuroxime was associated with an increased risk of 30 day mortality compared with penicillin (adjusted HR 2.54, 95% CI 1.49-4.32). Other variables that were statistically significantly associated with 30 day mortality included increasing age, disease severity and a primary respiratory focus. Osteomyelitis/arthritis was associated with a lower risk of death than were other secondary manifestations. Propensity-score-matched case-control studies confirmed an increased risk of 30 day mortality: cefuroxime treatment (39%) versus penicillin treatment (20%), P = 0.037; and cefuroxime treatment (38%) versus dicloxacillin treatment (10%), P = 0.004. CONCLUSIONS: Definitive therapy for penicillin-susceptible SAB with cefuroxime was associated with a significantly higher mortality than was seen with therapy with penicillin or dicloxacillin.
Journal of Antimicrobial Chemotherapy 04/2013; · 5.07 Impact Factor
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ABSTRACT: BACKGROUND: Information from blood cultures is utilized for infection control, public health surveillance, and clinical outcome research. This information can be enriched by physicians assessments of positive blood cultures, which are, however, often available from selected patient groups or pathogens only. The aim of this work was to determine whether patients with positive blood cultures can be classified effectively for outcome research in epidemiological studies by the use of administrative data and computer algorithms, taking physicians assessments as reference. METHODS: Physicians assessments of positive blood cultures were routinely recorded at two Danish hospitals from 2006 through 2008. The physicians assessments classified positive blood cultures as: a) contamination or bloodstream infection; b) bloodstream infection as mono- or polymicrobial; c) bloodstream infection as community- or hospital-onset; d) communityonset bloodstream infection as healthcare-associated or not. We applied the computer algorithms to data from laboratory databases and the Danish National Patient Registry to classify the same groups and compared these with the physicians assessments as reference episodes. For each classification, we tabulated episodes derived by the physicians assessment and the computer algorithm and compared 30-day mortality between concordant and discrepant groups with adjustment for age, gender, and comorbidity. RESULTS: Physicians derived 9,482 reference episodes from 21,705 positive blood cultures. The agreement between computer algorithms and physicians assessments was high for contamination vs. bloodstream infection (8,966/9,482 reference episodes [96.6%], Kappa = 0.83) and mono- vs. polymicrobial bloodstream infection (6,932/7,288 reference episodes [95.2%], Kappa = 0.76), but lower for community- vs. hospital-onset bloodstream infection (6,056/7,288 reference episodes [83.1%], Kappa = 0.57) and healthcare-association (3,032/4,740 reference episodes [64.0%], Kappa = 0.15). The 30-day mortality in the discrepant groups differed from the concordant groups as regards community- vs. hospitalonset, whereas there were no material differences within the other comparison groups. CONCLUSIONS: Using data from health administrative registries, we found high agreement between the computer algorithms and the physicians assessments as regards contamination vs. bloodstream infection and monomicrobial vs. polymicrobial bloodstream infection, whereas there was only moderate agreement between the computer algorithms and the physicians assessments concerning the place of onset. These results provide new information on the utility of computer algorithms derived from health administrative registries.
BMC Medical Research Methodology 09/2012; 12(1):139. · 2.67 Impact Factor
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Jens-Ulrik Stæhr Jensen,
Lars Hein,
Bettina Lundgren,
Morten Heiberg Bestle,
Thomas Mohr,
Mads Holmen Andersen,
Klaus Julius Thornberg,
Jesper Løken,
Morten Steensen,
Zoë Fox, [......],
Katrin Thormar,
Paul Christian Fjeldborg,
Kim Michael Larsen,
Niels-Erik Drenck,
Maria Egede Johansen,
Lene Ryom Nielsen, Christian Ostergaard,
Jesper Kjær,
Jesper Grarup,
Jens D Lundgren
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ABSTRACT: To explore whether a strategy of more intensive antibiotic therapy leads to emergence or prolongation of renal failure in intensive care patients.
Secondary analysis from a randomised antibiotic strategy trial (the Procalcitonin And Survival Study). The randomised arms were conserved from the primary trial for the main analysis.
Nine mixed surgical/medical intensive care units across Denmark.
1200 adult intensive care patients, 18+ years, expected to stay +24 h. Exclusion criteria: bilirubin >40 mg/dl, triglycerides >1000 mg/dl, increased risk from blood sampling, pregnant/breast feeding and psychiatric patients.
Patients were randomised to guideline-based therapy ('standard-exposure' arm) or to guideline-based therapy supplemented with antibiotic escalation whenever procalcitonin increased on daily measurements ('high-exposure' arm).
Primary end point: estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2). Secondary end points: (1) delta eGFR after starting/stopping a drug and (2) RIFLE criterion Risk 'R', Injury 'I' and Failure 'F'. Analysis was by intention to treat.
28-day mortality was 31.8% and comparable (Jensen et al, Crit Care Med 2011). A total of 3672/7634 (48.1%) study days during follow-up in the high-exposure versus 3016/6949 (43.4%) in the 'standard-exposure arm were spent with eGFR <60 ml/min/1.73 m(2), p<0.001. In a multiple effects model, 3 piperacillin/tazobactam was identified as causing the lowest rate of renal recovery of all antibiotics used: 1.0 ml/min/1.73 m(2)/24 h while exposed to this drug (95% CI 0.7 to 1.3 ml/min/1.73 m(2)/24 h) vs meropenem: 2.9 ml/min/1.73 m(2)/24 h (2.5 to 3.3 ml/min/1.73 m(2)/24 h)); after discontinuing piperacillin/tazobactam, the renal recovery rate increased: 2.7 ml/min/1.73 m(2)/24 h (2.3 to 3.1 ml/min/1.73 m(2) /24 h)). eGFR <60 ml/min/1.73 m(2) in the two groups at entry and at last day of follow-up was 57% versus 55% and 41% versus 39%, respectively.
Piperacillin/tazobactam was identified as a cause of delayed renal recovery in critically ill patients. This nephrotoxicity was not observed when using other beta-lactam antibiotics.
ClinicalTrials.gov identifier: NCT00271752.
BMJ open. 01/2012; 2(2):e000635.
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Jens U Jensen,
Lars Hein,
Bettina Lundgren,
Morten H Bestle,
Thomas T Mohr,
Mads H Andersen,
Klaus J Thornberg,
Jesper Løken,
Morten Steensen,
Zoe Fox, [......],
Nanna Reiter,
Søren Hestad,
Katrin Thormar,
Paul Fjeldborg,
Kim M Larsen,
Niels E Drenck, Christian Ostergaard,
Jesper Kjær,
Jesper Grarup,
Jens D Lundgren
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ABSTRACT: For patients in intensive care units, sepsis is a common and potentially deadly complication and prompt initiation of appropriate antimicrobial therapy improves prognosis. The objective of this trial was to determine whether a strategy of antimicrobial spectrum escalation, guided by daily measurements of the biomarker procalcitonin, could reduce the time to appropriate therapy, thus improving survival.
Randomized controlled open-label trial.
Nine multidisciplinary intensive care units across Denmark.
A total of 1,200 critically ill patients were included after meeting the following eligibility requirements: expected intensive care unit stay of ≥ 24 hrs, nonpregnant, judged to not be harmed by blood sampling, bilirubin <40 mg/dL, and triglycerides <1000 mg/dL (not suspensive).
: Patients were randomized either to the "standard-of-care-only arm," receiving treatment according to the current international guidelines and blinded to procalcitonin levels, or to the "procalcitonin arm," in which current guidelines were supplemented with a drug-escalation algorithm and intensified diagnostics based on daily procalcitonin measurements.
The primary end point was death from any cause at day 28; this occurred for 31.5% (190 of 604) patients in the procalcitonin arm and for 32.0% (191 of 596) patients in the standard-of-care-only arm (absolute risk reduction, 0.6%; 95% confidence interval [CI] -4.7% to 5.9%). Length of stay in the intensive care unit was increased by one day (p = .004) in the procalcitonin arm, the rate of mechanical ventilation per day in the intensive care unit increased 4.9% (95% CI, 3.0-6.7%), and the relative risk of days with estimated glomerular filtration rate <60 mL/min/1.73 m was 1.21 (95% CI, 1.15-1.27).
Procalcitonin-guided antimicrobial escalation in the intensive care unit did not improve survival and did lead to organ-related harm and prolonged admission to the intensive care unit. The procalcitonin strategy like the one used in this trial cannot be recommended.
Critical care medicine 05/2011; 39(9):2048-58. · 6.37 Impact Factor
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ABSTRACT: Intratympanic steroid treatment prevents hearing loss and cochlear damage in a rat model of pneumococcal meningitis.
Sensorineural hearing loss is a long-term complication of meningitis affecting up to a third of survivors. Streptococcus pneumoniae is the bacterial species most often associated with a hearing loss.
Rats were randomly assigned to 3 treatment groups: a group treated with intratympanic betamethasone and 2 control groups treated with either intratympanic or systemic saline. Treatment was initiated 21 hours after infection and repeated once a day for 3 days. Hearing loss and cochlear damage were assessed by distortion product otoacoustic emissions, auditory brainstem response at 16 kHz, and spiral ganglion neuron density.
Fifty-six days after infection, auditory brainstem response showed no significant differences between groups, and distortion product otoacoustic emissions showed significant hearing loss at the low frequencies in animals treated with intratympanic steroid compared with animals treated with systemic saline (p < 0.05; Mann-Whitney test). However, intratympanic steroid significantly increased the number of viable neurons in the spiral ganglion compared with both intratympanic and systemic saline (p = 0.0082 and p = 0.0089; Mann-Whitney test). Histology revealed fibrosis of the tympanic membrane and cavity in steroid-treated animals, which plausibly caused the low-frequency hearing loss.
Intratympanic betamethasone treatment prevents long-term spiral ganglion neuron loss in experimental pneumococcal meningitis. This finding is clinically relevant in relation to post-meningitic hearing rehabilitation by cochlear implantation. However, the drug instillation in the middle ear induced local fibrosis and a concurrent low-frequency hearing loss.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 02/2010; 31(3):394-403. · 1.44 Impact Factor
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ABSTRACT: A population-based nested case-control study was conducted in order to characterize patient factors and microbial species associated with recurrent bacteraemia.
All patients with bacteraemia in a Danish region during 1996-2006 were investigated. Recurrence was defined based on pathogen identity, site of infection and time frame, and not restricted to homologous pathogens.
We identified 8672 patients with first-time bacteraemia, of whom 1003 (12%) had a recurrence within 1 year. The proportion of mono-microbial bacteraemia was similar for first (86%) and recurrent episodes (84%). An unknown focus was common in both episodes (22.7 and 29.1%, respectively). Independent predictors of a recurrence (incidence rate ratio, 95% confidence interval) included health care-associated (2.4; 1.9-3.0) and nosocomial bacteraemia (2.1; 1.8-2.6), poly-microbial Gram-positive bacteraemia (2.7; 1.6-4.6), and fungaemia (2.2; 1.4-3.5), a Charlson co-morbidity index score of 1-2 (1.7; 1.4-2.1), inappropriate empirical antimicrobial chemotherapy (1.3; 1.1-1.5), a gastro-intestinal tract focus (2.3; 1.7-3.0), a liver/biliary tract focus (2.7; 2.0-3.6), an iv-catheter focus (2.0; 1.4-2.8), endocarditis (2.7; 1.6-4.3), and an unknown focus (1.9; 1.5-2.3).
This study showed recurrent bacteraemia to be common and the following risk factors were identified: a health care-associated or nosocomial origin, poly-microbial or fungal aetiology, a focus within the abdomen, endocardium, iv-catheter-related or unknown, a Charlson co-morbidity index score of >1 and inappropriate empirical antimicrobial chemotherapy.
The Journal of infection 12/2009; 60(3):191-9. · 4.13 Impact Factor
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Critical care medicine 08/2009; 37(7):2317-8. · 6.37 Impact Factor
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ABSTRACT: To examine the routes, dynamics and correlates of cochlear inflammation in meningitis to provide information on the pathogenesis of the associated hearing loss and indications for rational pharmacotherapeutical intervention.
A well-established rat model of Streptococcus pneumoniae meningitis was employed.
Eight rats were inoculated intrathecally and not treated, whereas 26 were inoculated and treated with ceftriaxone. Six rats were sham-inoculated, making a total of 40 rats. The rats were sacrificed when reaching terminal illness or after 7 days, followed by light microscopy. Routes of cochlear inflammatory infiltration were examined. The volume fraction of inflammatory infiltration was estimated and correlated to bacterial and leukocyte counts in cerebrospinal fluid (CSF) and blood.
The perilymphatic space was infiltrated with inflammatory cells via cochlear aqueduct, whereas the endolymphatic space was infiltrated from the spiral ligament. Rosenthal's canal was infiltrated through osseous spiral lamina canaliculi. In the untreated group, the degree of inflammation correlated with time of death, whereas antibiotic treatment reversed this development. Perilymphatic inflammation correlated significantly with the CSF leukocyte count, whereas endolymphatic inflammation correlated with spiral ligament inflammation.
Meningogenic inflammation of the rat cochlea occurs via the cochlear aqueduct and the spiral ligament capillary bed. The spiral ganglion is infiltrated through the osseous spiral lamina. The degree of inflammation correlates positively with time of death in untreated meningitis, whereas antibiotic treatment leads to subsiding infiltration during recovery.
The Laryngoscope 07/2009; 119(8):1560-70. · 1.75 Impact Factor
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ABSTRACT: Macrophage migration inhibitory factor (MIF) plays an essential pathophysiological role in septic shock, but its role in central nervous system infection (CNS) remains to be defined.
We investigated cerebrospinal fluid (CSF) levels of MIF in 171 patients who were clinically suspected of having meningitis on admission. Of these, 31 were found to have purulent meningitis of known aetiology, 20 purulent meningitis of unknown aetiology, 59 lymphocytic meningitis and 11 encephalitis, whereas 50 were suspected of having but had no evidence of CNS infection.
CSF MIF levels were significantly higher in patients with purulent meningitis of known aetiology (median [interquartile range]: 8,639 [3,344 to 20,600] ng/l) than in patients with purulent meningitis of unknown aetiology (2,209 [1,516 to 6,550] ng/l; Mann-Whitney test, P = 0.003), patients with lymphocytic meningitis (1,912 [1,302 to 4,105] ng/l; P < 0.001) and patients suspected of having but without evidence of CNS infection (1,472 [672 to 3,447] ng/l; P < 0.001). Also, patients with encephalitis (6,937 [3,961 to 8,353] ng/l) had higher CSF MIF than did patients without CNS infection (P < 0.01). Among patients with purulent meningitis, CSF MIF levels were significantly higher in patients infected with pneumococci than in those with meningococcal infection (11,569 [8,615 to 21,935] ng/l versus 5,006 [1,717 to 10,905] ng/l; P = 0.02), in patients who required versus those not requiring assisted ventilation (10,493 [5,961 to 22,725] ng/l versus 3,240 [1,563 to 9,302] ng/l; P = 0.003), and in patients with versus those without impaired consciousness (8,614 [3,344 to 20,935] ng/l versus 2,625 [1,561 to 7,530] ng/l; P = 0.02). CSF MIF levels correlated significantly with meningeal inflammation (P < 0.05) but not with systemic inflammatory response (P > 0.05) in patients with purulent meningitis of known aetiology, those with lymphocytic meningitis and those with encephalitis.
MIF was significantly increased in the CSF of patients with purulent meningitis and encephalitis, and was to some degree associated with severity of the infection. Our findings indicate that MIF may play an important role in CNS infection.
Critical care (London, England) 06/2009; 13(3):R101. · 4.61 Impact Factor
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ABSTRACT: Plectasin is the first defensin-type antimicrobial peptide isolated from a fungus and has potent activity against gram-positive bacteria. By using an experimental meningitis model, the penetration of plectasin into the cerebrospinal fluid (CSF) of infected and uninfected rabbits and the bactericidal activities in CSF of the plectasin variant NZ2114 and ceftriaxone against a penicillin-resistant Streptococcus pneumoniae strain (NZ2114 and ceftriaxone MICs, 0.25 and 0.5 microg/ml, respectively) were studied. Pharmacokinetic analysis showed that there was a significantly higher level of CSF penetration of NZ2114 through inflamed than through noninflamed meninges (area under the concentration-time curve for CSF/area under the concentration-time curve for serum, 33% and 1.1%, respectively; P = 0.03). The peak concentrations of NZ2114 in purulent CSF were observed approximately 3 h after the infusion of an intravenous bolus of either 20 or 40 mg/kg of body weight and exceeded the MIC >10-fold for a 6-h study period. Treatment with NZ2114 (40 and 20 mg/kg at 0 and 5 h, respectively; n = 11) caused a significantly higher reduction in CSF bacterial concentrations than therapy with ceftriaxone (125 mg/kg at 0 h; n = 7) at 3 h (median changes, 3.7 log(10) CFU/ml [interquartile range, 2.5 to 4.6 log(10) CFU/ml] and 2.1 log(10) CFU/ml [interquartile range, 1.7 to 2.6 log(10) CFU/ml], respectively; P = 0.001), 5 h (median changes, 5.2 log(10) CFU/ml [interquartile range, 3.6 to 6.1 log(10) CFU/ml] and 3.1 log(10) CFU/ml [interquartile range, 2.6 to 3.7 log(10) CFU/ml], respectively; P = 0.01), and 10 h (median changes, 5.6 log(10) CFU/ml [interquartile range, 5.2 to 5.9 log(10) CFU/ml] and 4.2 log(10) CFU/ml [interquartile range, 3.6 to 5.0 log(10) CFU/ml], respectively; P = 0.03) after the start of therapy as well compared to the CSF bacterial concentrations in untreated rabbits with meningitis (n = 7, P < 0.05). Also, significantly more rabbits had sterile CSF at 5 and 10 h when they were treated with NZ2114 than when they were treated with ceftriaxone (67% [six of nine rabbits] and 0% [zero of seven rabbits], respectively, at 5 h and 75% [six of eight rabbits] and 14% [one of seven rabbits], respectively, at 10 h; P < 0.05). Due to its excellent CSF penetration and potent bactericidal activity in CSF, the plectasin variant NZ2114 could be a promising new option for the treatment of CNS infections caused by gram-positive bacteria, including penicillin-resistant pneumococcal meningitis.
Antimicrobial Agents and Chemotherapy 02/2009; 53(4):1581-5. · 4.84 Impact Factor
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Jens-Ulrik Jensen,
Bettina Lundgren,
Lars Hein,
Thomas Mohr,
Pernille L Petersen,
Lasse H Andersen,
Anne O Lauritsen,
Sine Hougaard,
Teit Mantoni,
Bonnie Bømler, [......],
Søren Hestad,
Mads H Andersen,
Paul Fjeldborg,
Kim M Larsen,
Charlotte Rossau,
Carsten B Thomsen, Christian Ostergaard,
Jesper Kjaer,
Jesper Grarup,
Jens D Lundgren
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ABSTRACT: Sepsis and complications to sepsis are major causes of mortality in critically ill patients. Rapid treatment of sepsis is of crucial importance for survival of patients. The infectious status of the critically ill patient is often difficult to assess because symptoms cannot be expressed and signs may present atypically. The established biological markers of inflammation (leucocytes, C-reactive protein) may often be influenced by other parameters than infection, and may be unacceptably slowly released after progression of an infection. At the same time, lack of a relevant antimicrobial therapy in an early course of infection may be fatal for the patient. Specific and rapid markers of bacterial infection have been sought for use in these patients.
Multi-centre randomized controlled interventional trial. Powered for superiority and non-inferiority on all measured end points. Complies with, "Good Clinical Practice" (ICH-GCP Guideline (CPMP/ICH/135/95, Directive 2001/20/EC)). Inclusion: 1) Age > or = 18 years of age, 2) Admitted to the participating intensive care units, 3) Signed written informed consent.Exclusion: 1) Known hyper-bilirubinaemia. or hypertriglyceridaemia, 2) Likely that safety is compromised by blood sampling, 3) Pregnant or breast feeding. Computerized Randomisation: Two arms (1:1), n = 500 per arm: Arm 1: standard of care. Arm 2: standard of care and Procalcitonin guided diagnostics and treatment of infection. Primary Trial Objective: To address whether daily Procalcitonin measurements and immediate diagnostic and therapeutic response on day-to-day changes in procalcitonin can reduce the mortality of critically ill patients.
For the first time ever, a mortality-endpoint, large scale randomized controlled trial with a biomarker-guided strategy compared to the best standard of care, is conducted in an Intensive care setting. Results will, with a high statistical power answer the question: Can the survival of critically ill patients be improved by actively using biomarker procalcitonin in the treatment of infections? 700 critically ill patients are currently included of 1000 planned (June 2008). Two interim analyses have been passed without any safety or futility issues, and the third interim analysis is soon to take place. Trial registration number at clinicaltrials.gov: Id. nr.: NCT00271752).
BMC Infectious Diseases 07/2008; 8:91. · 3.12 Impact Factor
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ABSTRACT: Aerococcus sanguinicola is a Gram-positive coccus first described in 2001. Infections in humans are rare but the use of 16S rRNA gene sequencing and improved phenotypic methods has facilitated the identification of A. sanguinicola. We report here 6 cases of A. sanguinicola bacteraemia, 2 of which were associated with infective endocarditis. Most patients were elderly (median age 70 y) and had underlying neurological disorders including dementia, cerebral degeneration, and myelomeningocele. The primary focus of infection was the urinary tract in 3 cases and the gallbladder in 1; no focus was detected in 2 cases. Long-term prognosis was poor reflecting the frailty of the patients. All strains were susceptible to penicillin, ampicillin, cefuroxime, vancomycin, erythromycin, and rifampicin. The optimal treatment of infection with A. sanguinicola has yet to be determined.
Scandinavian Journal of Infectious Diseases 02/2008; 40(9):761-5. · 1.72 Impact Factor
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ABSTRACT: In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally (group A, N=10); saline intravenously and pneumococci intracisternally (group B, N=10); pneumococci intravenously and pneumococci intracisternally (group C, N=5); saline intravenously, antipneumococcal antibody intravenously (to prevent bacteremia), and pneumococci intracisternally (group D, N=10); or saline intravenously and saline intracisternally (group E, N=10), respectively. Positive cultures occurred in the blood for all rats in groups A, B, and C, and in the cerebrospinal fluid for all rats in groups D and E. Twenty-four hours after inoculation, CBF was measured with laser-Doppler ultrasound during incremental reductions in cerebral perfusion pressure (CPP) by controlled hemorrhage. Autoregulation was preserved in all rats without meningitis (groups A and E) and was lost in 24 of 25 meningitis rats (groups B, C, and D) (P<0.01). In group A, the lower limit was higher than that of group E (P<0.05). The slope of the CBF/CPP regression line differed between the meningitis groups (P<0.001), being steeper for group B than groups C and D, with no difference between these two groups. The results suggest that pneumococcal bacteremia in rats triggers cerebral vasodilation, which right shifts the lower limit of, but does not entirely abolish, CBF autoregulation in the absence of meningitis, and which may further aggravate the vasoparalysis induced by concomitant pneumococcal meningitis.
Journal of Cerebral Blood Flow & Metabolism 01/2008; 28(1):126-34. · 5.01 Impact Factor
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ABSTRACT: Bacteremia plays a major role in the outcome of pneumococcal meningitis. This experimental study investigated how bacteremia influences the pathophysiologic profile of the brain.
Rats with Streptococcus pneumoniae meningitis were randomized to 1 of 3 groups of infected study rats: (1) rats with attenuated bacteremia resulting from intravenous injection of serotype-specific pneumococcal antibody, (2) rats with early-onset bacteremia resulting from concomitant intravenous infection, or (3) a meningitis control group. The blood-brain barrier (BBB) breakdown, ventricle size, brain water distribution, and brain pathologic findings were analyzed using magnetic resonance morphological and functional imaging. Laboratory data and clinical disease scores were obtained.
Attenuation of the bacteremic component of pneumococcal meningitis improved clinical disease symptoms and significantly reduced ventricle expansion and BBB breakdown (P< .05). Early-onset bacteremia did not further increase ventricle size or BBB leakage. Significantly increased brain edema developed among rats with both attenuated and early-onset bacteremia (P< .05). Focal brain pathologic findings were unaffected by bacteremia and were found to be associated with cerebrospinal fluid inflammation.
Although brain lesions appear to result from local meningeal infection, systemic infection significantly contributes to clinical disease presentation and the pathophysiology of BBB breakdown and ventricle expansion. The different end points affected by the systemic and local infectious processes should be addressed in future studies.
The Journal of Infectious Diseases 01/2008; 197(2):235-44. · 6.41 Impact Factor
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ABSTRACT: Magnetic Resonance Imaging (MRI) methods were evaluated as a tool for the study of experimental meningitis. The identification and characterisation of pathophysiological parameters that vary during the course of the disease could be used as markers for future studies of new treatment strategies.
Rats infected intracisternally with S. pneumoniae (n = 29) or saline (n = 13) were randomized for imaging at 6, 12, 24, 30, 36, 42 or 48 hours after infection. T1W, T2W, quantitative diffusion, and post contrast T1W images were acquired at 4.7 T. Dynamic MRI (dMRI) was used to evaluate blood-brain-barrier (BBB) permeability and to obtain a measure of cerebral and muscle perfusion. Clinical- and motor scores, bacterial counts in CSF and blood, and WBC counts in CSF were measured.
MR images and dMRI revealed the development of a highly significant increase in BBB permeability (P < 0.002) and ventricle size (P < 0.0001) among infected rats. Clinical disease severity was closely related to ventricle expansion (P = 0.024). Changes in brain water distribution, assessed by ADC, and categorization of brain 'perfusion' by cortex DeltaSI(bolus) were subject to increased inter-rat variation as the disease progressed, but without overall differences compared to uninfected rats (P > 0.05). Areas of well-'perfused' muscle decreased with the progression of infection indicative of septicaemia (P = 0.05).
The evolution of bacterial meningitis was successfully followed in-vivo with MRI. Increasing BBB-breakdown and ventricle size was observed in rats with meningitis whereas changes in brain water distribution were heterogeneous. MRI will be a valuable technique for future studies aiming at evaluating or optimizing adjunctive treatments.
BMC Medical Imaging 01/2008; 8:1. · 1.09 Impact Factor
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ABSTRACT: We studied cerebral blood flow (CBF) autoregulation and intracranial pressure (ICP) during normo- and hyperventilation in a rat model of Streptococcus pneumoniae meningitis. Meningitis was induced by intracisternal injection of S. pneumoniae. Mean arterial blood pressure (MAP), ICP, cerebral perfusion pressure (CPP, defined as MAP - ICP), and laser-Doppler CBF were measured in anesthetized infected rats (n = 30) and saline-inoculated controls (n = 30). CPP was either incrementally reduced by controlled hemorrhage or increased by intravenous norepinephrine infusion. Twelve hours postinoculation, rats were studied solely during normocapnia, whereas rats studied after 24 h were exposed to either normocapnia or to acute hypocapnia. In infected rats compared with control rats, ICP was unchanged at 12 h but increased at 24 h postinoculation (not significant and P < 0.01, respectively); hypocapnia did not lower ICP compared with normocapnia. Twelve hours postinoculation, CBF autoregulation was lost in all infected rats but preserved in all control rats (P < 0.01). Twenty-four hours after inoculation, 10% of infected rats had preserved CBF autoregulation during normocapnia compared with 80% of control rats (P < 0.01). In contrast, 60% of the infected rats and 100% of the control rats showed an intact CBF autoregulation during hypocapnia (P < 0.05 for the comparison of infected rats at normocapnia vs. hypocapnia). In conclusion, CBF autoregulation is lost both at 12 and at 24 h after intracisternal inoculation of S. pneumoniae in rats. Impairment of CBF autoregulation precedes the increase in ICP, and acute hypocapnia may restore autoregulation without changing the ICP.
Journal of Applied Physiology 01/2007; 102(1):72-8. · 3.75 Impact Factor
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ABSTRACT: The role of leukocyte accumulation in the cerebrospinal fluid (CSF) in the evolution of the pathophysiological changes that occur in bacterial meningitis is unclear. Here, we investigate how leukocyte recruitment to the CSF, modulated by the leukocyte blocker fucoidin, affects the extent of brain damage and outcome in pneumococcal meningitis in rats treated with ceftriaxone from 28 h after infection. Rats treated with fucoidin from time of infection had an excess risk of a fatal outcome compared to rats not receiving fucoidin (25/63 versus 5/34, p=0.012), whereas the risk of cortical damage in surviving animals was comparable (16/44 versus 9/29, p=0.8). Pre-treatment with fucoidin attenuated CSF pleocytosis 24 h after infection (median 400 versus 800x10(6) cells/l, p=0.01) without affecting CSF bacterial counts (2.3x10(5) versus 3.6x10(5) CFU/ml, p=0.54). A significant increase in blood bacterial counts was found among rats pre-treated with fucoidin (median 9.6x10(2) versus 5.2x10(2) CFU/ml, p=0.03). Furthermore, blood bacterial count was found to be an important predictor of fatal outcome as shown by multivariate logistical regression analysis (OR 4.43, 95% CI [1.16-17.0] p=0.03). In summary, blocking leukocyte entry to the central nervous system in experimental pneumococcal meningitis compromises the survival prognosis but does not affect the risk of brain damage or level of infection in this compartment. Conversely, poorer prognosis was associated with an increase in bacterial load in blood, suggesting that leukocyte blockage affects the host's ability to control systemic infection.
Journal of Neuroimmunology 10/2005; 166(1-2):126-31. · 2.96 Impact Factor
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ABSTRACT: The urokinase-type plasminogen activator system has been suggested to play a pathophysiological role in brain damage. The aim of this study was to evaluate CSF levels of suPAR in 183 patients clinically suspected of having meningitis on admission. Of these, 54 patients were found to have purulent meningitis, 63 had lymphocytic meningitis, 12 had encephalitis, and 54 patients were suspected of, but had no evidence of, meningitis. There was a significant difference in suPAR levels among patient groups (Kruskal Wallis test, p < 0.0001) with significantly higher CSF suPAR levels in patients with CNS infection (purulent meningitis: median suPAR 2.41 microg/l (range 0.12-35), lymphocytic meningitis: 1.10 microg/l (0.15-5.31), and encephalitis (1.77 microg/l (0.17-11.7)) than in patients without meningitis (0.64 microg/l (0-5.34) (Dunn's multiple comparison test, p < 0.05). Also, patients with purulent meningitis had significantly higher CSF suPAR levels than patients with lymphocytic meningitis (p < 0.001). Patients with purulent meningitis who died (n = 8, 4.9 microg/l (1.3-35) had significantly higher CSF levels of suPAR than patients who survived (n = 46, 2.1 microg/l (0.1-24), Mann Whitney, p = 0.046). Employing a cut-off point of 3.1 and above, the OR (95%CI) for fatal outcome was 11.9 (1.4-106), univariate logistic regression analysis, p = 0.026. In conclusion, CSF suPAR levels may be an important predictor for fatal outcome in purulent meningitis.
Scandinavian Journal of Infectious Diseases 02/2004; 36(1):14-9. · 1.72 Impact Factor
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ABSTRACT: YKL40 is secreted by activated macrophages and neutrophils. Elevated serum concentrations of YKL40 are found in patients with diseases characterized by inflammation or ongoing fibrosis. The aim of this study was to evaluate serum YKL-40 levels in patients with Streptococcus pneumoniae bacteremia and to correlate these levels with clinical findings and outcomes. YKL40 was determined by ELISA and 89 patients were included in the study. Serum YKL-40 levels were significantly higher in patients with S. pneumoniae bacteremia (median 342 microg/l; range 20-20,400 microg/l) than in age-matched healthy subjects (44 microg/l; 20-184; p < 0.001). Serum YKL-40 levels were related to the severity of the infection, with significantly higher serum YKL-40 levels being observed in patients who needed hemodialysis (p < 0.001), pharmacological treatment of hypotension (p < 0.001) and mechanical ventilation (p = 0.003) compared to those in patients who did not need this supportive treatment. Nineteen patients died and these patients had significantly higher serum YKL-40 levels (980 microg/l; 88-20,400 microg/l) than those of survivors (256 microg/l; 20-9,100 microg/l; p < 0.001). Serum YKL40 level was an independent prognostic factor of survival in logistic multivariate regression analysis (p = 0.002). In conclusion, high serum levels of YKL40 indicated a poorer prognosis for patients with S. pneumoniae bacteremia.
Scandinavian Journal of Infectious Diseases 01/2002; 34(5):323-6. · 1.72 Impact Factor
