Ventricular fluid concentrations of vancomycin in children after intravenous and intraventricular administration

Trimethoprim-sulfamethoxazole treatment for meningitis owing to multidrug-resistant Elizabethkingia meningoseptica in an extremely low-birthweight, premature infant

Elizabethkingia meningoseptica is a recognised cause of meningitis in premature neonates and severe infections in immunocompromised adults; multi-drug resistance is a major issue. A premature infant developed sepsis, meningitis and hydrocephalus owing to E. meningoseptica and was treated successfully with trimethoprim-sulfamethoxazole (TMP-SMZ) for 3 weeks. A ventriculoperitoneal shunt was required for hydrocephalus. This is the youngest patient with meningitis caused by E. meningoseptica to have responded to TMP-SMZ.

Management of complicated shunt infections: a clinical report

OBJECTIVES

The authors present their experience with a protocol for the treatment of patients with complicated shunt infections.

METHODS

Complicated shunt infections are defined for the purpose of this protocol as multiple compartment hydrocephalus, multiple organism shunt infection, severe peritonitis, or infections in other sites of the body. The initial treatment protocol for these patients was 3 weeks of intravenous antibiotic therapy and 2 weeks of twice daily intraventricular/intrashunt antibiotic therapy. Cerebrospinal fluid (CSF) cultures were monitored during therapy and obtained again 48 hours after completion. The shunt was completely replaced. Additionally, follow-up cultures were obtained in all patients 3-6 months after therapy was completed.

RESULTS

A cure of the infection was achieved in all patients as defined by negative cultures obtained at completion of antibiotic therapy and in follow-up studies. The follow-up period was 2-11 years (mean 4.4 +/- 2.5 years). The treatment protocol was modified in the patients treated after 1991, and 18 patients were treated with this modified treatment regime. In these patients, intraventricular antibiotics were administered only once daily for 14 days, and the CSF was cultured 24 hours after antibiotic therapy had been stopped instead of after 48 hours. The results were similar to those obtained with the initial protocol.

CONCLUSIONS

Based on their prospective nonrandomized series, the authors believe that patients with complicated shunt infections can be successfully treated with 2 weeks of intraventricular antibiotic therapy administered once daily, concurrent with 3 weeks of intravenous antibiotic therapy. This protocol reduces length of treatment and hospital stay, and avoids recurrence of infection.

Aggressive management of shunt infection: combined intravenous and intraventricular antibiotic therapy for twelve or less days

OBJECTIVE

This report is limited to patients with a single cerebrospinal fluid (CSF) shunt infected by a single organism, and compares two treatment protocols.

METHODS

In the initial protocol (1975-1991), patients underwent removal of the shunt system and received intravenous and intraventricular antibiotics. Intraventricular antibiotics were administered twice daily to those with external ventricular drainage. When CSF was cultured 48 h off all antibiotics and found to be sterile at 24 h of incubation, a new shunt was inserted. Follow-up CSF cultures were obtained in all patients between 1-6 months following placement of the new shunt.

RESULTS

There were 25 patients (ages 1 month to 16 years; mean +/- SD: 23 +/- 4.0 months). CSF obtained from the shunt yielded the following: Staphylococcus epidermidis (19), Staphylococcus aureus (2), Streptococcus species (2), Serratia marcescens (1), and Propionebacterium species (1). The duration of intravenous antibiotics was 7-12 days (mean +/- SD: 9.7 +/- 1.3 days), and intraventricular antibiotic therapy was 6.2 +/- 1.7 days. Total hospital stay was 15.2 +/- 2.3 days. The follow-up period was 7.7 +/- 3.6 years. Following the initial protocol in another 15 patients (1992-2004), the treatment regime was modified in that intraventricular antibiotics were administered once daily in patients with external ventricular drainage, and the CSF was cultured at 24 h off antibiotics, instead of 48 h. Results were similar to the initial protocol with respect to days of antibiotic therapy and hospital stay.

CONCLUSION

Based on our retrospective nonrandomized series, we believe patients with a single shunt and noncompartmentalized hydrocephalus can be successfully treated without a prolonged antibiotic course and lengthy hospital stay.

Vancomycin disposition and penetration into ventricular fluid of the central nervous system following intravenous therapy in patients with cerebrospinal devices

OBJECTIVE/AIMS

To determine the cerebrospinal fluid concentrations and percent CNS penetration of intravenous vancomycin in patients with cerebrospinal devices at a pediatric institution.

METHODS

We performed a prospective evaluation of intravenous (IV) vancomycin in patients who received a single prophylactic dose of vancomycin (15-20 mg/, maximum dose 1 g) prior to insertion of a CNS shunt (group I) or a therapeutic regimen (a dose of 10-20 mg/kg every 6-12 h) for a documented/suspected shunt infection (group II). Ventricular cerebrospinal fluid (VCSF) samples were taken during the procedure in group I and multiple serum and VCSF samples were collected in group II. Pharmacokinetic parameters were calculated using a one-compartment model, and percent CNS penetration was estimated using area-under-the-curve methodology.

RESULTS

Group I: 21 VCSF samples were analyzed from 19 patients (mean age 7.2 +/- 6.4 years). Over 40% of samples failed to have detectable vancomycin concentrations (range 0-2 microg/ml). Group II: 6 patients (mean age 11 +/- 8.7 years) had VCSF concentrations ranging from nondetectable to 6.59 microg/ml (mean 2.48 +/- 0.52 microg/ml). Percent penetration ranged from 0.77 to 18%.

CONCLUSIONS

Single-dose, pre-operative vancomycin results in low VCSF vancomycin concentrations and repeated dosing in patients with documented/presumed device infections yields variable CNS penetration.

Vancomycin

This review describes the use of vancomycin in neonates over the last three decades. Given the relation of late-onset neonatal septicaemia to outcome and the increase in coagulase-negative staphylococcal infection as causative organism, vancomycin remains an important antibacterial in the neonatal intensive care unit. The pharmacokinetic behaviour of vancomycin in neonates can be adequately described by a one- or two-compartment model and is mainly determined by postconceptional age and renal function. In neonates, a patent ductus arteriosus as well as treatment with indomethacin or extracorporeal membrane oxygenation (ECMO) leads to an increase in volume of distribution and a decrease in clearance. Microbiological studies in vitro have shown that an increase in vancomycin concentrations above the minimum inhibitory concentration does not result in more effective killing. The microbiological and clinical efficacy of vancomycin in neonates has only been studied explicitly in a restricted number of patients. There are no definitive data relating serum concentrations to effect in this patient group. Vancomycin-related nephrotoxicity and ototoxicity in neonates is rare, and no clear relation to serum concentrations has been demonstrated. Based on the pharmacokinetic profile of vancomycin in neonates, several administration regimens have been constructed. Recent guidelines have suggested that dosage can be independent of gestational age or postconceptional age in neonates without renal failure. In patients with renal failure, therapy can be adequately tailored by using a regimen based on serum creatinine. The usefulness of routine monitoring of peak serum concentrations is doubtful based on the current literature. Recent research demonstrates a shift towards taking only routine trough serum concentrations in order to optimise efficacy. Patients with renal failure and other special subpopulations, such as patients exposed to ECMO or indomethacin, need to be monitored more closely.

Special considerations for monitoring vancomycin concentrations in pediatric patients

The objectives of this study were to estimate the prevalence of low or excessive vancomycin dosing after initiation of treatment in pediatric patients and to determine the factors that are most predictive of optimized vancomycin dosage in this group. Among 74 patients who underwent vancomycin concentration monitoring, low trough (< 4.0 micrograms/ml) and/or peak (< 15.0 micrograms/ml) concentrations were noted in 28 (38%) patients after the initiation of therapy but in only four of the 28 (14%) patients (p = 0.29) after optimization of the initial dosage. There were not toxic peak concentrations (> 60 micrograms/ml) reported during the study. In patients older than 1 month old, 11 low peaks were associated with troughs less than 7.5 micrograms/ml, whereas no low peaks were associated with troughs more than 7.5 micrograms/ml. The significant predictive variables of optimized vancomycin dosage in the reduced regression model (p < 0.00001; adjusted r2 =0.85; n = 36) were (log) initial dose (p < 0.0001), initial trough (p < 0.0001), and age (p = 0.009). Initial peak concentrations were not associated with the optimized dosage (p = 0.50). The results of this study indicate that approximately 40% of all pediatric patients will be at risk of significant underdosing if standard vancomycin dosing guidelines are followed and that patients older than 1 month old with initial trough concentrations less than 7.5 micrograms/ml are at a greater risk of low peak concentrations than individuals with trough concentrations more than 7.5 micrograms/ml. Monitoring vancomycin concentrations appears to be essential to prevent the underdosing of many pediatric patients; however, only initial trough vancomycin concentrations may be needed to optimize dosages.

Pharmacokinetics of anti-infective agents in paediatric patients

Various differences in drug disposition exist between children and adults. For example, the volume of distribution (Vd) for many drugs is larger in children than in adults. Other parameters, including excretion and elimination may be altered in children compared with adults. The penicillins and cephalosporins are used commonly for the treatment of infection in paediatric patients. The increased Vd in children contributes to the increased elimination half-life of these agents. Clearance of the acylureido-penicillins is increased in children with cystic fibrosis, a disease that decreases the elimination half-life for these drugs. Aminoglycosides distribute into extracellular fluid and their pharmacokinetic profile is affected by changes in Vd. The Vd for aminoglycosides is slightly higher in children than in adults. Children with cystic fibrosis, burns, or cancer have higher clearance rates and larger Vd values for aminoglycosides. Few data in the literature address the pharmacokinetics of other anti-infective agents, including vancomycin, teicoplanin, erythromycin, metronidazole, chloramphenicol, and cotrimoxazole (trimethoprim-sulfamethoxazole), in children. Similarly, there is little information regarding the pharmacokinetic profile of antivirals and antifungals in children. Dosage guidelines are available to enable the clinician to initiate anti-infective therapy in children. Subsequent dosage requirements may change based on the patient's current clinical condition. Although several studies have investigated the pharmacokinetics of anti-infectives in neonates and adults, data for children are limited. Therefore, further studies are required so that the ever growing arsenal of anti-infectives can be administered appropriately to children.