Inflamed Meninges Research Articles

Effects of EDP-420 on penicillin-resistant and quinolone- and penicillin-resistant pneumococci in the rabbit meningitis model

To test the efficacy of EDP-420, a new ketolide, in experimental pneumococcal meningitis and to determine its penetration into the CSF. The experimental rabbit model was used in this study and EDP-420 was tested against a penicillin-resistant and a penicillin- and quinolone-resistant mutant. EDP-420 was also tested against both strains in time-killing assays over 8 h in vitro. In experimental meningitis, EDP-420 produced a bactericidal activity comparable to the standard regimen based on a combination of vancomycin with ceftriaxone against a penicillin-resistant Streptococcus pneumoniae and a penicillin- and quinolone-resistant S. pneumoniae isolate. The penetration of EDP-420 into inflamed meninges was 38% after an i.v. injection of 10 mg/kg. The bactericidal activity of EDP-420 was also confirmed in in vitro time-killing assays. EDP-420 is an efficacious alternative treatment in pneumococcal meningitis, especially when resistant strains are suspected.

Daptomycin is more efficacious than vancomycin against a methicillin-susceptible Staphylococcus aureus in experimental meningitis

To test the efficacy of daptomycin, a cyclic lipopeptide antibiotic, against a methicillin-susceptible Staphylococcus aureus strain in experimental rabbit meningitis and to determine its penetration into non-inflamed and inflamed meninges Over a treatment period of 8 h, daptomycin (15 mg/kg) was significantly superior to the comparator regimen vancomycin (-4.54 +/- 1.12 log(10)/mL for daptomycin versus -3.43 +/- 1.17 log(10)/mL for vancomycin). Daptomycin managed to sterilize 6 out of 10 CSFs compared with 4 out of 10 for vancomycin. The penetration of daptomycin into inflamed meninges was approximately 5% and approximately 2% into non-inflamed meninges. The superior bactericidal activity of daptomycin was confirmed in vivo and in time-killing assays in vitro.

Efficacy of Telavancin against Penicillin-Resistant Pneumococci and Staphylococcus aureus in a Rabbit Meningitis Model and Determination of Kinetic Parameters

The penetration of telavancin was 2% into inflamed meninges and ca. 1 per thousand into noninflamed meninges after two intravenous injections (30 mg/kg of body weight). In experimental meningitis, telavancin was significantly superior to vancomycin combined with ceftriaxone against a penicillin-resistant pneumococcal strain. Against a methicillin-sensitive staphylococcal strain, telavancin was slightly but not significantly superior to vancomycin.

Daptomycin is highly efficacious against penicillin-resistant and penicillin- and quinolone-resistant pneumococci in experimental meningitis.

The penetration of daptomycin, a new lipopeptide antibiotic, into inflamed meninges ranged between 4.37 and 7.53% (mean, 5.97%). Daptomycin was very efficacious in the treatment of experimental pneumococcal meningitis, producing a decrease of -1.20 +/- 0.32 Deltalog(10) CFU/ml. h in the bacterial titer of Streptococcus pneumoniae against a penicillin-resistant strain and of -0.97 +/- 0.32 Deltalog(10) CFU/ml. h against a penicillin- and quinolone-resistant strain found in cerebrospinal fluid (CSF). For both strains, daptomycin was significantly superior to the standard regimen of a combination of ceftriaxone with vancomycin, sterilizing 9 of 10 CSF samples after 4 h. In vitro, daptomycin produced highly bactericidal activity in concentrations above the MIC.

Activities of ertapenem, a new long-acting carbapenem, against penicillin-sensitive or -resistant pneumococci in experimental meningitis.

The penetration of ertapenem, a new carbapenem with a long half-life, reached 7.1 and 2.4% into inflamed and noninflamed meninges, respectively. Ertapenem had excellent antibacterial activity in the treatment of experimental meningitis due to penicillin-sensitive and -resistant pneumococci, leading to a decrease of 0.69 +/- 0.17 and 0.59 +/- 0.22 log(10) CFU/ml x h, respectively, in the viable cell counts in the cerebrospinal fluid. The efficacy of ertapenem was comparable to that of standard regimens (ceftriaxone monotherapy against the penicillin-sensitive strain and ceftriaxone combined with vancomycin against the penicillin-resistant strain). In vitro, ertapenem in concentrations above the MIC was highly bactericidal against both strains. Even against a penicillin- and quinolone-resistant mutant, ertapenem had similar bactericidal activity in vitro.

Gemifloxacin is efficacious against penicillin-resistant and quinolone-resistant pneumococci in experimental meningitis.

In experimental rabbit meningitis, gemifloxacin penetrated inflamed meninges well (22 to 33%) and produced excellent bactericidal activity (change in log(10) [Deltalog(10)] CFU/ml/h, -0.68 +/- 0.30 [mean and standard deviation]), even superior to that of the standard regimen of ceftriaxone plus vancomycin (-0.49 +/- 0.09 deltalog(10) CFU/ml/h), in the treatment of meningitis due to a penicillin-resistant pneumococcal strain (MIC, 4 mg/liter). Even against a penicillin- and quinolone-resistant strain, gemifloxacin showed good bactericidal activity (-0.48 +/- 0.16 deltalog(10) CFU/ml/h). The excellent antibacterial activity of gemifloxacin was also confirmed by time-kill assays over 8 h in vitro.

Efficacies of BMS 284756 against penicillin-sensitive, penicillin-resistant, and quinolone-resistant pneumococci in experimental meningitis.

BMS 284756 penetrated well into inflamed meninges (44% +/- 11%) and produced good bactericidal activity (-0.82 +/- 0.22 Delta log(10) CFU/ml. h) in the treatment of experimental meningitis in rabbits due to a penicillin-sensitive strain. BMS 284756 monotherapy had a greater potency than the standard regimen of ceftriaxone and vancomycin (-0.49 +/- 0.08 Delta log(10) CFU/ml. h) against a penicillin-resistant strain (MIC, 4 mg/liter). Even against a penicillin- and quinolone-resistant strain, BMS 284756 showed good bactericidal activity (-0.52 +/- 0.12 Delta log(10) CFU/ml. h). The antibacterial activity of BMS 284756 was confirmed by time-killing assays over 8 h in vitro.

Commonly used antibacterial and antifungal agents for hospitalised paediatric patients: implications for therapy with an emphasis on clinical pharmacokinetics.

Due to normal growth and development, hospitalised paediatric patients with infection require unique consideration of immune function and drug disposition. Specifically, antibacterial and antifungal pharmacokinetics are influenced by volume of distribution, drug binding and elimination, which are a reflection of changing extracellular fluid volume, quantity and quality of plasma proteins, and renal and hepatic function. However, there is a paucity of data in paediatric patients addressing these issues and many empiric treatment practices are based on adult data. The penicillins and cephalosporins continue to be a mainstay of therapy because of their broad spectrum of activity, clinical efficacy and favourable tolerability profile. These antibacterials rapidly reach peak serum concentrations and readily diffuse into body tissues. Good penetration into the cerebrospinal fluid (CSF) has made the third-generation cephalosporins the agents of choice for the treatment of bacterial meningitis. These drugs are excreted primarily by the kidney. The carbapenems are broad-spectrum beta-lactam antibacterials which can potentially replace combination regimens. Vancomycin is a glycopeptide antibacterial with gram-positive activity useful for the treatment of resistant infections, or for those patients allergic to penicillins and cephalosporins. Volume of distribution is affected by age, gender, and bodyweight. It diffuses well across serous membranes and inflamed meninges. Vancomycin is excreted by the kidneys and is not removed by dialysis. The aminoglycosides continue to serve a useful role in the treatment of gram-negative, enterococcal and mycobacterial infections. Their volume of distribution approximates extracellular space. These drugs are also excreted renally and are removed by haemodialysis. Passage across the blood-brain barrier is poor, even in the face of meningeal inflammation. Low pH found in abscess conditions impairs function. Toxicity needs to be considered. Macrolide antibacterials are frequently used in the treatment of respiratory infections. Parenteral erythromycin can cause phlebitis, which limits its use. Parenteral azithromycin is better tolerated but paediatric pharmacokinetic data are lacking. Clindamycin is frequently used when anaerobic infections are suspected. Good oral absorption makes it a good choice for step-down therapy in intra-abdominal and skeletal infections. The use of quinolones in paediatrics has been restricted and most information available is in cystic fibrosis patients. High oral bioavailability is also important for step-down therapy. Amphotericin B has been the cornerstone of antifungal treatment in hospitalised patients. Its metabolism is poorly understood. The half-life increases with time and can be as long as 15 days after prolonged therapy. Oral absorption is poor. The azole antifungals are being used increasingly. Fluconazole is well tolerated, with high bioavailability and good penetration into the CSF. Itraconazole has greater activity against aspergillus, blastomycosis, histoplasmosis and sporotrichosis, although it's pharmacological and toxicity profiles are not as favourable.

Penetration of rufloxacin into the cerebrospinal fluid in patients with inflamed and uninflamed meninges.

Forty-four patients scheduled for lumbar puncture (LP) were recruited to determine the level of penetration of orally administered rufloxacin into cerebrospinal fluid (CSF). The patients were divided into three clinical groups: those with normal CSF (groups A(1d) and A(7d)), those with aseptic meningitis (group B), and those with bacterial meningitis (group C). Members of group A(1d) received a single 400-mg rufloxacin dose, while group A(7d), B, and C constituents had a multiple-dose regimen (one 400-mg dose, followed by one 200-mg dose daily for 6 days). LP was performed on group A(1d) members 5 h after they had received treatment, while for group A(7d) it was undertaken 5 h after administration of the last dose. For group B, LP was performed 5 h after the first and the last doses, whereas for group C it was undertaken after the first, fourth, and last doses. Concentrations of rufloxacin in simultaneously collected CSF and plasma samples were determined. Mean CSF/plasma rufloxacin concentration ratios ranged from 0.57 to 0.84, depending on the study group. A higher, but not statistically significant, degree of penetration into CSF was observed in patients with bacterial meningitis than in those with normal CSF or aseptic meningitis. These data indicate that rufloxacin diffuses efficiently into the CSF of patients with either inflamed or uninflamed meninges.

Lymphocytic Choriomeningitis Virus Infection is Associated with Long‐Standing Perturbation of LFA‐1 Expression on CD8+ T Cells

Flow cytometric analysis of splenocytes from mice infected with lymphocytic choriomeningitis virus revealed marked and long-standing up-regulation of LFA-1 expression on CD8+, but not on CD4+ T cells. Appearance of CD8+ T cells with a changed expression of adhesion molecules reflected polyclonal activation and expansion which was demonstrated not to depend on CD4+ T cells or their products. Cell sorting experiments defined virus-specific CTL to be included in this population (LFA-1hiMEL-14lo), but since about 80% of splenic CD8+ T cells have a changed phenotype, extensive bystander activation must take place; this is indicated also by the finding that CD8+LFA-1hi cells transiently express several markers of cellular activation, e.g. transferrin receptor, IL-2R alpha and beta. Analysis of cells from the cerebrospinal fluid of mice infected intracerebrally showed that virtually all T cells present belonged to the CD8+LFA-1hi subset and, correspondingly, the ligand ICAM-1 was found to be up-regulated on endothelial cells in the inflamed meninges. Preincubation of LCMV-primed donor splenocytes with anti-LFA-1 markedly inhibited the transfer of virus-specific delayed-type hypersensitivity to naive recipients. Together, these findings indicate that up-regulation of LFA-1 expression is a critical factor involved in directing activated CD8+ T cells to sites of viral infection.

Kinetics of ofloxacin and its metabolites in cerebrospinal fluid after a single intravenous infusion of 400 milligrams of ofloxacin

Ofloxacin has been reported to diffuse readily into the cerebrospinal fluid (CSF) in subjects with both inflamed and uninflamed meninges. However, with moderately susceptible bacteria, ofloxacin concentrations in CSF may be subtherapeutic after administration of an intravenous (i.v.) dose of 200 mg. For this reason, the kinetics of a higher dose of ofloxacin in CSF was studied with humans. Six patients with occlusive hydrocephalus caused by cerebrovascular diseases who had undergone external ventriculostomy received 400 mg of ofloxacin i.v. over 30 min. Serum and CSF samples were drawn repeatedly. Serum from 12 healthy volunteers was sampled repeatedly after they had received 400 mg of ofloxacin i.v. over 60 min. Ofloxacin, ofloxacin-N-oxide, and N-desmethyl-ofloxacin concentrations were determined by high-pressure liquid chromatography with fluorescence detection. The maximum ofloxacin concentrations in the serum of the patients ranged from 7.36 to 11.6 mg/liter (mean, 9.55 mg/liter), the apparent volume of distribution/body weight was 0.96 to 1.19 liters/kg (mean, 1.11 liters/kg), and the total body clearance was 115 to 280 ml/min (mean, 192 ml/min). In healthy volunteers, the volume of distribution/body weight and the total body clearance were higher and amounted to 1.27 +/- 0.18 liters/kg and 217 +/- 43 ml/min (means +/- standard deviations), respectively. These differences were attributed to the older ages of the patients than the volunteers. In the CSF of patients, maximum concentrations of 1.00 to 2.85 mg/liter (mean, 2.04 mg/liter) were observed 0.5 to 4 h following the completion of the ofloxacin infusion. Ofloxacin elimination from CSF was slightly slower than that from serum (half-lives, 4.33 to 10.02 versus 4.27 to 9.14 h). The overall penetration of ofloxacin into CSF, as expressed by the ratios of the areas under the concentration-curves, amounted to 0.59 to 0.81 (mean, 0.65). The more hydrophilic metabolites ofloxacin-N-oxide and N-desmethyl-ofloxacin passed less readily than ofloxacin into the CSF. In conclusion, the concentrations in CSF attained after a single i.v. infusion of 400 mg of ofloxacin in the absence of meningeal inflammation appear to be high enough to inhibit the growth of most staphylococci and members of the family Enterobacteriaceae, which are often involved in CSF shunt infection. Yet, in view of pharmacodynamic studies suggesting a peak concentration in CSF of at least 10-fold the MIC, the use of ofloxacin for central nervous systems infections is optimal only with highly susceptible pathogens (MIC, less than or equal to 0.12 mg/liter).

Clinical pharmacokinetics of aztreonam. An update.

Plasma concentrations of aztreonam follow a 2-compartment open model with a distribution half-life of 0.20 hours after intravenous injection. The volume of distribution at steady-state (Vss) after intravenous and intramuscular injection is about 0.16 L/kg (0.42 L/kg for free drug). After intramuscular injection, absorption is almost complete. Absorption after intraperitoneal administration in patients with peritonitis is 92%. Over a large dosage range, plasma concentrations increase dose proportionally. In healthy individuals, about 56% of the drug is plasma protein bound. Diffusion into tissues is generally slow, and the ratio between mean tissue and plasma aztreonam concentration seems to depend mainly on tissue composition. Aztreonam penetrates into cerebrospinal fluid (CSF) more rapidly in patients with inflamed meninges than in those with noninflamed meninges. Diffusion through the placenta is poor, as is diffusion into breastmilk. Aztreonam is predominantly eliminated by the kidney, partly by active tubular excretion. Extrarenal clearance appears to be through hepatic excretion. Metabolism occurs to a very limited extent. Total plasma clearance (CLp) in healthy adults is about 5.6 L/h and the terminal elimination half-life is 1.7 to 2.0 hours. CLp is similar in both children and adults when expressed as a function of bodyweight. However, in neonates, especially in low birthweight infants, CLp is lower. In various disease states, the Vss of aztreonam is not appreciably different from that found in healthy individuals. However, patients with low serum albumin levels (e.g. burn patients, critically ill patients and those with cirrhosis of the liver) generally have an increased volume of distribution. The elimination half-life of the drug is dependent on renal function.(ABSTRACT TRUNCATED AT 250 WORDS)

Passage of cefotaxime and ceftriaxone into cerebrospinal fluid of patients with uninflamed meninges

Cefotaxime and ceftriaxone have proven to be effective in pyogenic infections of the central nervous system. Since in some bacterial central nervous system infections the blood-cerebrospinal fluid (CSF) barrier is either minimally impaired or recovers in the course of the illness, we studied the penetration of both antibiotics in the absence of inflamed meninges. Patients who had undergone external ventriculostomies for noninflammatory occlusive hydrocephalus received either cefotaxime (2 g/30 min) or ceftriaxone (2 g/30 min) to treat extracerebral infections. Serum and CSF were drawn repeatedly after the first dose. With ceftriaxone, they were also drawn after the last dose. The concentrations of cefotaxime, its metabolite desacetylcefotaxime, and ceftriaxone were determined by high-performance liquid chromatography with UV detection. Maximum concentrations of cefotaxime in CSF were reached 0.5 to 8 h (median = 3 h; n = 6) after the end of the infusion and ranged from 0.14 to 1.81 mg/liter (median = 0.44 mg/liter; n = 6). Maximum levels of ceftriaxone in CSF ranging from 0.18 to 1.04 mg/liter (median = 0.43 mg/liter; n = 5) were seen 1 to 16 h (median = 12 h; n = 5) after the infusion. The elimination half-life of cefotaxime in CSF was 5.0 to 26.9 h (median = 9.3 h; n = 5), and that of ceftriaxone was 15.7 to 18.4 h (median = 16.8 h; n = 3). It is concluded that after a single dose of 2 g, maximal concentrations of cefotaxime and ceftriaxone in CSF do not differ substantially. The long elimination half-lives guarantee uniform concentrations in CSF. These concentrations reliably inhibit highly susceptible bacteria but cannot be relied on to inhibit staphylococci and penicillin G-resistant Streptococcus pneumoniae.

An improved clinical method for detecting meningeal irritation.

Neck stiffness is the most important sign of meningitis. When the neck is flexed, the inflamed nerve roots and meninges of the cervical region get stretched. This causes protective muscle spasm manifesting as neck stiffness. Kernig's sign represents similar phenomena involving the distal spinal cord and related nerves. A manoeuvre that stretches the neural elements of the whole length of the spinal canal simultaneously will be a more sensitive test for meningeal irritation. Eliciting neck stiffness while the patient sits up with knees extended achieves this. This method is more sensitive, specific, and amenable to objective assessment.

Penetration of ciprofloxacin into human cerebrospinal fluid in patients with inflamed and non-inflamed meninges

The penetration of ciprofloxacin into the cerebrospinal fluid (CSF) in 25 patients with non-inflamed meninges and in 9 patients with inflamed meninges was studied. In the patients with non-inflamed meninges plasma and CSF were obtained 1-10 h after the second dose of ciprofloxacin and in the patients with inflamed meninges 1, 2, 3, 5, 7 and 9 h after the second dose. In the first group (non-inflamed meninges) data from 6 patients were obtained 4, 5 and 6 h post-dose. Mean ciprofloxacin concentrations in the CSF ranged from 0.073 mg/l to 0.106 mg/l during this observation time, while in the second group (inflamed meninges) they ranged from 0.089 to 0.260 mg/l. These results demonstrate that ciprofloxacin diffuses into the CSF at concentrations which exceed the MICs of Neisseria meningitidis and most gram-negative aerobic bacilli.

Clinical pharmacokinetics of aztreonam.

Aztreonam (azthreonam) is practically completely absorbed after intramuscular injection. After intravenous injection plasma concentrations follow a 2-compartment open model, with a t1/2 alpha of 0.20 hours. Volume of distribution at steady-state (Vdss) after intravenous or intramuscular injection is about 0.16 L/kg (0.42 L/kg for the free drug). After oral administration less than 1% of the drug is absorbed. Over a large dosage range plasma concentrations increase linearly with dose. No accumulation occurs after multiple dosing. Plasma binding in healthy subjects is about 56% and is not concentration dependent. Diffusion into tissues is generally slow, and the ratio between mean tissue and plasma concentration seems to depend mainly on the composition of the tissue. In inflamed meninges, penetration of aztreonam into CSF is more rapid than with uninflamed meninges. Diffusion through the placenta is poor, as is diffusion into breast milk. The main route of elimination of aztreonam is by the kidney, partly by active tubular excretion, but this can be inhibited by probenecid. Extrarenal clearance is probably due to excretion by the liver. Metabolism occurs to a very limited extent. Total plasma clearance in healthy adults is about 140 ml/min (8.4 L/h) or 2 ml/min/kg (0.12 L/h/kg), and terminal half-life is 1.7 hours. In children clearance is similar to that in adults when expressed as a function of bodyweight, but in neonates, especially in low birthweight infants, it is less [about 1 ml/min/kg (0.06 L/h/kg)]. In various disease states the Vdss of aztreonam is not appreciably different from that found in healthy individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Quinolones in the treatment of infections of the central nervous system.

The literature concerning the penetration of new 4-quinolones into the cerebrospinal fluid (CSF) and brain tissue is reviewed as well as the few reports on clinical use of these antibiotics in the treatment of infections of the central nervous system (CNS). Pefloxacin has been found to penetrate well into the CSF of patients with normal or inflamed meninges as well as into brain tissue. Ciprofloxacin also penetrates into CSF, although not as well as pefloxacin. Two patients with meningitis due to Pseudomonas aeruginosa have been reported to have recovered after treatment with ciprofloxacin. Because of the spectrum limitations of quinolones, especially with regard to anaerobes and gram-positive aerobic cocci, these agents should not be considered for empiric use in CNS infections. They may, however, become alternatives in the rare cases of CNS infection caused by organisms resistant to other antibiotics.

Penetration of fosfomycin into cerebrospinal fluid across non-inflamed and inflamed meninges.

Serum and cerebrospinal fluid (CSF) concentrations of fosfomycin were evaluated in 45 patients. Mean serum concentration was 260.1 mg/l at 15 min postinfusion in 35 patients receiving a 5 g bolus dose, and 440 mg/l in five patients receiving a 10 g bolus dose. Mean distribution volume was 18.5 l (5 g dose), the total clearance was 118.8 ml/min, half-life was nearly 2 h, and the determined AUC were 420.95 mg/l.h (5 g dose) and 423.57 mg/l.h (10 g dose). The average peaks at 360 min in CSF reached 11.6 mg/l (5 g dose) and 17.7 mg/l (10 g dose). The CSF/serum ratio was 9.24% (5 g dose), and 13.81% (10 g dose). The CSF levels were not below 30 mg/l from the second day on in patients receiving 3 X 5 g fosfomycin per day. Meningeal inflammation increased the CSF concentrations from 30 mg/l at 6 h up to 150 mg/l at 120 h in the saturation phase, e. g., up to 300% more in comparison to non-inflamed meninges.

Penetration of amoxicillin and potassium clavulanate into the cerebrospinal fluid of patients with inflamed meninges.

A single intravenous dose of 2.0 g of amoxicillin and 0.2 g of potassium clavulanate was given to patients with bacterial meningitis, and the pharmacokinetics of both drugs in the cerebrospinal fluid (CSF) and plasma were evaluated. Twenty-one patients aged 14 to 76 years were studied. Both amoxicillin and potassium clavulanate were detectable in the CSF as early as 1 h and reached peak concentrations by approximately 2 h. The highest mean CSF concentrations were 2.25 micrograms/ml for amoxicillin and 0.25 micrograms/ml for potassium clavulanate and were found in patients with moderately or severely inflamed meninges. The CSF penetration relative to plasma for amoxicillin and potassium clavulanate was 5.8 and 8.4%, respectively. These levels suggest that the amoxicillin-potassium clavulanate combination may be effective for the treatment of bacterial meningitis caused by beta-lactamase-producing pathogens.

Penetration of aztreonam into cerebrospinal fluid of patients with and without inflamed meninges.

Aztreonam was administered as a single, 2-g intravenous dose to 25 patients with noninflamed meninges and to 9 patients with inflamed meninges. It was well tolerated and was detected in the cerebrospinal fluid at the initial sampling period at 1 h after the end of infusion. Aztreonam levels in the cerebrospinal fluid of patients with inflamed meninges were four times higher than those recorded for the same time period in patients with noninflamed meninges. Aztreonam concentrations in cerebrospinal fluid in the presence of normal and inflamed meninges exceeded the inhibitory and bactericidal concentrations for most gram-negative bacteria. Thus, a multiple-dose treatment regimen with 2-g intravenous doses every 6 h appears to be appropriate for clinical trials of aztreonam for the treatment of gram-negative bacillary meningitis which is caused by susceptible organisms.