A rapid, automatic and accurate assay for quantifying temocillin in human serum and CSF using turbulent flow liquid chromatography coupled to high-resolution mass spectrometry. Clinical application.

Temocillin is a ß-lactamase-resistant penicillin used for the treatment of multiple drug-resistant Gram-negative bacteria. To maximize efficacy and avoid adverse effects, the dose regimen has to be quickly adjusted to the clinical situations. This necessitates the development of a rapid, reliable and accurate analytical method. Temocillin and the stable isotopically labeled internal standard ([13 C6 ]-amoxicillin) were extracted from either serum or cerebrospinal fluid by a turbulent flow liquid chromatographic method and eluted onto an octadecyl-silica phase with polar endcapping. Mass spectrometry was conducted using an exact mass determination method by electrospray positive ionization high-resolution mass spectrometry. The LLOQ and ULOQ of the present method were determined to be 0.4 and 200 µg/ml for serum and cerebrospinal fluid samples, respectively. The total analysis time was <7 min. The recovery ranged from 87.7 to 120.8%. Intra- and inter-day precision and trueness were tested at four concentration levels: 0.4, 8, 40 and 160 µg/ml. Values were 6.33 ± 1.53, 8.8 ± 1.3, 8.8 ± 0.36 and 2.1 ± 0.76%, and 5.0 ± 0.54, 9.9 ± 1.0, 5.8 ± 1.6 and 0.1 ± 1.1%, for inter- and intra-day analysis, respectively. Temocillin was found to be stable under all relevant laboratory conditions. The method was cross-validated with a microbiological assay. This method is suitable for accurate measurement of temocillin concentration in small volumes of serum or cerebrospinal fluid. Thanks to the online extraction procedure, the overall analytical time is compatible with high-throughput analysis for clinical application.

Multidrug-resistant Klebsiella oxytoca ventriculitis, successfully treated with intraventricular tigecycline: A case report.

A 38-year-old male presented to the hospital with headache, fever, and meningeal signs. He had undergone a surgical review of a ventriculoperitoneal shunt system one month earlier. A head computed tomography scan showed hydrocephalus. His medical history included a human immunodeficiency virus infection identified four years before and resolved cryptococcal meningitis, which had necessitated the implantation of the shunt system. Ventricular cerebrospinal fluid (CSF) was obtained, which showed inflammation and, in culture, grew a Gram-negative bacillus identified as multidrug-resistant Klebsiella oxytoca. The shunt was removed and a ventricular drain was installed. Treatment with meropenem and amikacin was established without a response; the CSF white blood cell count continued to increase, with cultures remaining positive. The patient's clinical condition deteriorated to stupor. With informed consent, intraventricular (ITV) treatment with tigecycline was initiated at a dose of 5 mg every 24 h and, three days later, the CSF cultures were negativized. Tigecycline levels in the CSF were quantified by liquid chromatography with ultraviolet detection and showed peak concentrations achieved at two hours after the dose of between 178 and 310 µg/mL. After 11 days of treatment with ITV tigecycline and eight negative CSF cultures, a new CSF shunt was installed. During follow-up review 10 months later, the patient reported he was working. The dose of tigecycline used in this study produced levels 15 to 20 times the minimum inhibitory concentration of the bacteria for up to six hours with adequate tolerance.

Penicillin and ceftriaxone susceptibility of Streptococcus pneumoniae isolated from cerebrospinal fluid of children with meningitis hospitalized in a tertiary hospital in Israel.

BACKGROUND: Streptococcus pneumoniae is now the predominant pathogen causing meningitis. The resistance of S. pneumoniae to penicillin and third-generation cephalosporins has grown steadily. OBJECTIVES: To assess the antibiotic susceptibility of S. pneumoniae isolated from the cerebrospinal fluid of children with meningitis, and determine the antibiotic regimen appropriate for suspected bacterial meningitis in Israel. METHODS: The study group included 31 children with 35 episodes of meningitis hospitalized from 1998 to 2006. S. pneumoniae isolates from the cerebrospinal fluid were tested for susceptibility to penicillin and ceftriaxone. RESULTS: Of the 35 isolates, 17 (48.6%) showed resistance to penicillin (minimum inhibitory concentration > or = 0.12 microg/ml). Only 3 isolates (8.6%) showed intermediate resistance to ceftriaxone (> or = 0.5 and < (2 microg/ml), and none showed complete resistance (MIC > or = 2 microg/ml). The rates of antibiotic resistance were higher in children who were treated with antibiotics prior to admission (penicillin 88.9% vs. 34.6%, P = 0.007; ceftriaxone 22.2% vs. 3.8%, P = 0.156). CONCLUSIONS: The rate of penicillin resistance is high in children with S. pneumoniae meningitis in Israel, especially in those treated with oral antibiotics prior to admission. Resistance to ceftriaxone is infrequent though not negligible. On the basis of these findings, current recommendations to empirically treat all children with suspected bacterial meningitis with ceftriaxone in addition to vancomycin until the bacterial susceptibility results become available are justified also in Israel.

Clinical significance of cerebrospinal fluid inhibitory titers of antibiotics, based on pharmacokinetic/pharmacodynamic parameters, in the treatment of bacterial meningitis.

The cerebrospinal fluid (CSF) inhibitory titer (CSF-IT) of an antibiotic, which can be used to estimate the duration of time above the agent's MIC in the CSF, was introduced as one of the indices to evaluate the effectiveness of antibiotic selection in treating bacterial meningitis. The CSF-IT was determined via a microdilution method. A suspension of the causative organism was added to a tube containing twofold diluted CSF and double-concentrated Mueller-Hinton broth with supplement. The CSF-IT was determined by the maximum point without turbidity of medium after overnight incubation at 37 degrees C. Concerning the strain of beta-lactamase-negative ampicillin-resistant Haemophilus influenzae (BLNAR), the killing rates of both meropenem and piperacillin were compared in an in vitro pharmacokinetic (PK) model, in which human pharmacokinetics in CSF were simulated. Organisms recovered from the CSF in 37 treated clinical cases of bacterial meningitis were H. influenzae, Streptococcus agalactiae, Streptococcus pneumoniae, Escherichia coli, and Neisseria meningitidis; in these cases, the CSF-IT ranged from 1: 8 to as high as 1: 4 096. In the in vitro PK model, the concentrations of both drugs were higher than the MICs over a period of 24 h; however, the killing rate of piperacillin was higher than that of meropenem, and bacterial regrowth was observed after the administration of meropenem. A CSF-IT value higher than 1: 32 indicates that the antibiotic concentration in the CSF exceeds the MIC for 24 h. The effect of piperacillin on BLNAR depends not only on the time above MIC of 24 h but also on the maximum concentration in the CSF.

Antibiotic prophylaxis in cerebrospinal fluid shunting: reassessment of Cefotiam penetration into human CSF.

OBJECTS: Shunt infection is a major complication of shunt implantation. Numerous clinical studies give evidence that antibiotic prophylaxis is efficacious in preventing infections after cerebrospinal fluid shunting. In CSF shunting, antibiotics need to reach sufficient concentrations not only in the blood shielding the operative field but also in tissues and the CSF compartment. Cefotiam is widely used for prophylaxis in neurosurgery. Some clinical trials report that this beta-lactam is able to penetrate considerably into the CSF. However, these studies include disease patterns which are most likely to be associated with a pathological permeability of the blood-brain barrier. Therefore, this study was designed to investigate the extent of penetration of Cefotiam into human CSF in patients without morphological disruption of the blood-brain barrier. METHODS: The penetration of Cefotiam into human CSF was investigated in 23 patients without morphological disruption of the blood-brain barrier undergoing CSF shunt surgery. 2 g Cefotiam was administered prior to surgery as a short-term infusion for a period of 15 min. Samples of blood and CSF were collected intraoperatively. The concentrations of Cefotiam were determined by bioassay. RESULTS: All patients (n=23) showed moderate to high plasma levels of Cefotiam (range: 19.8-146.2 mg/L); the pharmacokinetic profiles in blood accorded well with published data. In contrast to earlier studies, no Cefotiam was detected in CSF. CONCLUSION: This study clearly demonstrates that Cefotiam does not penetrate through an intact blood-brain barrier into human CSF. Although Cefotiam has been shown to be valuable for the perioperative prophylaxis of shunt infection, other antibiotics might be superior if they are capable of entering the CSF. Further studies are required to address this assumption.

Evaluation of fusidic acid in therapy of experimental Staphylococcus aureus meningitis.

OBJECTIVES: Combination therapy that includes fusidic acid, an antimicrobial agent highly active against staphylococci, has been recommended in the treatment of patients with Staphylococcus aureus meningitis. The aim of this study was to evaluate the pharmacokinetic, CSF bactericidal and anti-inflammatory properties of fusidic acid. METHODS: The pharmacokinetics, treatment efficacy and parameters of the meningeal inflammatory response were studied in rabbits, using an experimental meningitis model against S. aureus (MICs of fusidic acid and methicillin were 0.125 and 1 mg/L, respectively). RESULTS: Fusidic acid entered the CSF, with peak values within 0.5-1 h of the intravenous bolus injection/infusion and with a percentage penetration (AUCCSF/AUCserum) into uninfected and purulent CSF of 1.9% +/- 0.7 and 4.5% +/- 0.7, respectively. Rabbits treated with antibiotics [fusidic acid 80 mg/kg/6 h (n = 6), methicillin 80 mg/kg/3 h (n = 7) and the two combined (n = 6)] had significantly higher bacterial kill rates than untreated controls (n = 6, P < 0.05). Combination therapy was less effective, with significantly less killing after 6 h of treatment than methicillin alone (P < 0.05). CSF white blood cells and CSF levels of interleukin-8 (IL-8), glucose, lactate and protein were altered during staphylococcal meningitis, but with no significant difference between antibiotic-treated and untreated rabbits. CONCLUSIONS: Antagonism between methicillin and fusidic acid was observed in staphylococcal meningitis.

Failure of treatment for chronic Mycobacterium abscessus meningitis despite adequate clarithromycin levels in cerebrospinal fluid.

We report a case of posttraumatic meningitis due to Mycobacterium abscessus, treated initially with oral clarithromycin and intravenous amikacin plus intrathecal amikacin. Despite cerebrospinal fluid (CSF) levels of clarithromycin and amikacin in excess of their in vitro minimum inhibitory concentrations for the organism, the CSF cultures remained continuously positive for M. abscessus. To our knowledge, this is the first documented case of M. abscessus meningitis and the first report of measured CSF levels of clarithromycin in a patient with meningitis, showing that even therapeutic CSF levels of clarithromycin and amikacin might not be successful in eradicating M. abscessus meningitis.

Pharmacokinetic optimisation of the treatment of bacterial central nervous system infections.

Central nervous system (CNS) infections caused by bacteria with reduced sensitivity to antibacterials are an increasing worldwide challenge. In successfully treating these infections the following conditions should be considered: (i) Antibacterials do not distribute homogeneously in the central nervous compartments [cerebrospinal fluid (CSF), extracellular space of the nervous tissue, intracellular space of the neurons, glial cells and leucocytes]. Even within the CSF, after intravenous administration, a ventriculo-lumbar concentration gradient is often observed. (ii) Valid parameters of drug entry into the CSF are the CSF: serum concentration ratio in steady state and the CSF: serum ratio of the area under the concentration-time curves (AUCCSF/AUCS). Frequently, the elimination half-life (t1/2 beta) in CSF is longer than t1/2 beta in serum. (iii) For most antibacterials, lipophilicity, molecular weight and serum protein binding determine the drug entry into the CSF and brain tissue. With an intact blood-CSF and blood-brain barrier, the entry of hydrophilic antibacterials (beta-lactam antibacterials, glycopeptides) into the CNS compartments is poor and increases during meningeal inflammation. More lipophilic compounds [metronidazole, quinolones, rifampicin (rifampin) and chloramphenicol] are less dependent on the function of the blood-CSF and blood-brain barrier. (iv) Determination of the minimal inhibitory concentrations (MIC) of the causative organism is necessary for optimisation of treatment. (v) For rapid sterilisation of CSF, drug concentrations of at least 10 times MIC are required. The minimum CSF concentration: MIC ratio ensuring successful therapy is unknown. Strategies to achieve optimum antibacterial concentrations in the presence of minor disturbances of the blood-CSF and blood-brain barrier include, the increased use of low toxicity antibacterials (e.g., beta-lactam antibiotics), the use of moderately lipophilic compounds, and the combination of intravenous and intraventricular administration. Antibacterials which do not interfere with bacterial cell wall synthesis delay and/or decrease the liberation of proinflammatory bacterial products, delay or inhibit tumour necrosis factor release, and may reduce brain oedema in experimental meningitis. Conclusive evidence of the reduction of neuronal damage by this approach, however, is lacking.

Bactericidal activity against intermediately cephalosporin-resistant Streptococcus pneumoniae in cerebrospinal fluid of children with bacterial meningitis treated with high doses of cefotaxime and vancomycin.

Cerebrospinal fluid (CSF) was taken from 19 children with bacterial meningitis treated with cefotaxime (300 mg/kg of body weight/day) and vancomycin (60 mg/kg/day). Median levels of drugs in CSF were smaller than expected, as follows: 4.4 microg/ml for cefotaxime, 3.2 microg/ml for desacetylcefotaxime, and 1.7 microg/ml for vancomycin. The median CSF bactericidal titer against an intermediately cefotaxime-resistant pneumococcus was 1:4. Our data suggest at least an additive interaction between the drugs used in this study.

Trovafloxacin in treatment of rabbits with experimental meningitis caused by high-level penicillin-resistant Streptococcus pneumoniae.

The fluoroquinolone trovafloxacin was bactericidal (0.47 +/- 0.23 delta log10 CFU/ml x h after 10 mg/kg of body weight and 0.78 +/- 0.15 delta log10 CFU/ml x h after 30 mg/kg) in the treatment of experimental meningitis caused by a highly penicillin-resistant (MIC and minimum bactericidal concentration = 4 and 4 microg/ml) strain of Streptococcus pneumoniae. Combinations with ampicillin and rifampin were indifferent compared to single drugs.

Clindamycin therapy of experimental meningitis caused by penicillin- and cephalosporin-resistant Streptococcus pneumoniae.

Although penicillin resistance among Streptococcus pneumoniae strains is increasing in many areas, resistance to clindamycin remains low. In our well-characterized rabbit meningitis model, we conducted experiments to evaluate the bacteriologic efficacy of clindamycin after a penicillin- and cephalosporin-resistant S. pneumoniae strain was intracisternally inoculated. Animals received a loading intravenous dose of 30 mg of clindamycin per kg of body weight and then two doses of 20 mg/kg given 5 h apart. In addition to clindamycin, some animals received dexamethasone (DXM) with or without ceftriaxone. The concentrations of clindamycin in cerebrospinal fluid were from 8.9 to 12.8% of the concomitant concentrations in serum and were unaffected by DXM administration. Mean changes in CFU (log10 per milliliter) at 10 and 24 h were -3.7 and -6.1, respectively, for clindamycin-treated rabbits, -3.6 and -6.3 for clindamycin-DXM-treated rabbits, -3.9 and -5.8, respectively, for clindamycin-ceftriaxone-treated rabbits, and -5.0 and -6.7, respectively, for clindamycin-ceftriaxone-DXM-treated rabbits. By 24 h all but one of the cultures of cerebrospinal fluid (that from a clindamycin-DXM-treated rabbit) were sterile. Because of the potential risk for clindamycin-treated rabbits to develop macrolide-lincosamide resistance, we attempted, unsuccessfully, to induce clindamycin resistance in vitro in two S. pneumoniae strains. Although clindamycin therapy might be effective in selected patients with multiple-drug-resistant pneumococcal meningitis who have failed conventional treatments, clinical experience is necessary before it can be recommended.

Co-trimoxazole versus nafcillin in the therapy of experimental meningitis due to Staphylococcus aureus.

Co-trimoxazole was compared with nafcillin against Staphylococcus aureus in vitro and in the therapy of experimental Staph. aureus meningitis in rabbits. Co-trimoxazole (trimethoprim:sulphamethoxazole in a 1:20 ratio) was synergistic against 22/24 strains of Staph. aureus in vitro. The MBC90 of co-trimoxazole and nafcillin were 0.156-3.12 mg/l and 0.25 mg/l, respectively, concentrations below those achievable in purulent cerebrospinal fluid. The rate of bacterial killing (Staph. aureus) by co-trimoxazole and nafcillin were similar in both broth and pooled CSF in vitro. However, the MBC increased and the rate of bactericidal activity of both agents declined when tested in CSF at a higher inoculum (10(7) cfu/ml). During continuous intravenous infusion therapy of a reproducible, uniformly fatal (if untreated) model of experimental Staph. aureus meningitis, serum concentrations of all agents closely approximated those found in humans receiving standard parenteral regimens. The mean percent penetration into CSF ([CSF]/[serum] X 100) was 2.9, 35.6 and 27.1% for nafcillin, trimethoprim and sulphamethoxazole, respectively. Although both nafcillin and co-trimoxazole therapy reduced CSF Staph. aureus concentrations significantly more rapidly (P less than 0.001) when compared to untreated controls, the bactericidal rate was modest. The CSF was rendered sterile in 0/64 animals treated with either regimen for 8 h. Nafcillin was more rapidly bactericidal in vivo (P less than 0.03) than co-trimoxazole in this model. Caution is advised in the use of co-trimoxazole for infections of the central nervous system caused by Staph. aureus.

Efficacy of teicoplanin in experimental group B streptococcal bacteremia and meningitis.

We evaluated the activity of teicoplanin against a type-III group B streptococcal strain in vitro and in vivo and compared the results with those of penicillin G. In vitro, the minimal inhibitory and minimal bactericidal concentrations of teicoplanin were 2- to 4-fold greater than those of penicillin G. In vivo studies were carried out with an experimental bacteremia and meningitis model in newborn rats. Eighty-one infected animals were randomized to receive teicoplanin 5, 10 or 20 mg/kg, twice daily, or penicillin G 50 or 200 mg/kg, twice daily, or saline (0.05 ml), twice daily. The mean serum levels of teicoplanin were maintained above 100 X the minimal bactericidal concentration for 7-8 h even with a dose of 5 mg/kg. The mean penetration of teicoplanin into the cerebrospinal fluid was estimated as 2.4-8.2% of those of concomitant levels in serum. The overall efficacy of teicoplanin was similar to that of penicillin G as judged by mortality rates. However, two bacteremic animals which were free of meningitis at the beginning of therapy developed this complication during 4 days of teicoplanin therapy, in contrast with none in the penicillin group. Further studies are needed to understand the reason(s) for these failures with teicoplanin therapy.

Aztreonam therapy in experimental meningitis due to Haemophilus influenzae type b and Escherichia coli K1.

The penetration of aztreonam into cerebrospinal fluid was 7 to 15% and 9 to 25%, respectively, in experimental Haemophilus influenzae type b and Escherichia coli K1 meningitis. Aztreonam was effective in reducing the number of organisms in cerebrospinal fluid after single-dose and continuous infusion administration, and the median bactericidal titers in cerebrospinal fluid were 1:32 against both meningeal pathogens.

[Current aspects of pseudomonas meningitis]. / Aktuelle Aspekte der Pseudomonasmeningitis.

The article reports on the incidence, the conditions of occurrence, possibilities and successes of treatment with certain (combinations of) antibiotics, in dealing with cases of pseudomonas meningitis. The various possible substances used for treatment are discussed. Rates of penetration and CSF concentrations of azlocillin and cefsulodin are stated. Alternative possibilities for treatment are pointed out.

Susceptibility of penicillin-resistant pneumococci to eighteen antimicrobials: implications for treatment of meningitis.

The minimal inhibitory concentrations (MICs) of 18 antibiotics including 16 beta-lactam antibiotics were determined by agar dilution on 70 strains of pneumococci (25 penicillin sensitive, 18 intermediate resistant and 27 resistant). The antimicrobials tested were penicillin G, ampicillin, carbenicillin, ticarcillin, piperacillin, mezlocillin, cephalothin, cefoxitin, cefamandole, latamoxef (moxalactam), cefotaxime, cefoperazone, ceftazidime, ceftriaxone, N-formimidoyl thienamycin, SCH 29482, chloramphenicol and vancomycin. Of these agents, only cefotaxime demonstrated greater activity than penicillin against intermediate penicillin-resistant strains while cefoperazone, ceftriaxone, N-formimidoyl thienamycin and vancomycin as well as cefotaxime demonstrated activity superior to penicillin against penicillin-resistant strains. Comparison of the MIC90s of these agents with the achievable cerebrospinal fluid levels suggests that meningitis caused by penicillin-resistant pneumococci should respond to treatment with cefotaxime, cefoperazone, ceftriaxone and vancomycin.

[Control of the effectiveness of antibiotic therapy by determining the antibacterial activity of the blood and cerebrospinal fluid]. / Practica controlului eficientei antibioticoterapiei prin determinarea actiunii antibacteriene a serului si lichidului cefalorahidian.

Determination of the antibacterial action of serum and the cerebrospinal fluid (CSF) is an excellent method for controlling the efficiency of antibioticotherapy in severe bacterial infections such as septicemia, endocarditis, meningitis. The author studied comparatively two methods for determining the antibacterial action of serum and CSF, namely dilution of the standard inoculum and diffusimetric methods. There was satisfactory agreement between the two methods. Hence, diffusimetry, a simple readily performed method, may be considered as an orientative test of the greatest utility, available for any of the lesser clinical laboratories.