Cefotaxime therapy of bacterial meningitis in children

Systematic Review of the Pharmacological Evidence for the Selection of Antimicrobials in Bacterial Infections of the Central Nervous System in Dogs and Cats

Bacterial meningitis in dogs and cats is a rare disease associated with a high lethality rate. The spectrum of causative bacteria includes a diverse set of gram positive, gram negative and anaerobic species. Currently, no veterinary medicinal product is approved for this indication in these species in Europe. The objective of this review was to collect the available pharmacokinetic data for antibiotics approved in dogs and cats to enable a preliminary analysis of their potential effectiveness for the treatment of bacterial meningitis. This analysis yielded data for 13 different antibiotics in dogs and two in cats. Additionally, data about frequently recommended cephalosporines not approved in dogs and cats were included. The collected data was used to assess the potential of the respective antibiotics to attain certain simple pharmacokinetic-pharmacodynamic (PK-PD) indexes in the cerebrospinal fluid (CSF). A more sophisticated investigation using modern methods was not possible due to the limited data available. For this purpose, data about the sensitivity of four bacterial species commonly associated with meningitis in dogs and cats to these antibiotics were included. The analysis provided evidence for the potential effectiveness of ampicillin, doxycycline, enrofloxacin, ceftriaxone and cefoxitin against bacteria frequently detected in bacterial meningitis in dogs. Data were not available or insufficient for the assessment of several antibiotics, including frequently recommended substances like metronidazole and trimethoprim-sulphonamide. Little evidence is available for the use of antibiotics in cats afflicted with this disease, highlighting the need for further research to obtain data for evidence based therapeutic recommendations.

Antibiotic regimens for early-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Possibly due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units. The last Cochrane Review was updated in 2004. Given the clinical importance, an updated systematic review assessing the effects of different antibiotic regimens for early-onset neonatal sepsis is needed.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for early-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2020, Issue 8); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for early-onset neonatal sepsis. We included participants from birth to 72 hours of life at randomisation.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (865 participants). All trials were at high risk of bias. The certainty of the evidence according to GRADE was very low. The included trials assessed five different comparisons of antibiotics. We did not conduct any meta-analyses due to lack of relevant data. Of the five included trials one trial compared ampicillin plus gentamicin with benzylpenicillin plus gentamicin; one trial compared piperacillin plus tazobactam with amikacin; one trial compared ticarcillin plus clavulanic acid with piperacillin plus gentamicin; one trial compared piperacillin with ampicillin plus amikacin; and one trial compared ceftazidime with benzylpenicillin plus gentamicin. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. Large RCTs assessing different antibiotic regimens in early-onset neonatal sepsis with low risk of bias are warranted.

Antibiotic regimens for late-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units, and observational studies in high-income countries suggest that 83% to 94% of newborns treated with antibiotics for suspected sepsis have negative blood cultures. The last Cochrane Review was updated in 2005. There is a need for an updated systematic review assessing the effects of different antibiotic regimens for late-onset neonatal sepsis.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for late-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2021, Issue 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for late-onset neonatal sepsis. We included participants older than 72 hours of life at randomisation, suspected or diagnosed with neonatal sepsis, meningitis, osteomyelitis, endocarditis, or necrotising enterocolitis. We excluded trials that assessed treatment of fungal infections.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (580 participants). All trials were at high risk of bias, and had very low-certainty evidence. The five included trials assessed five different comparisons of antibiotics. We did not conduct a meta-analysis due to lack of relevant data. Of the five included trials one trial compared cefazolin plus amikacin with vancomycin plus amikacin; one trial compared ticarcillin plus clavulanic acid with flucloxacillin plus gentamicin; one trial compared cloxacillin plus amikacin with cefotaxime plus gentamicin; one trial compared meropenem with standard care (ampicillin plus gentamicin or cefotaxime plus gentamicin); and one trial compared vancomycin plus gentamicin with vancomycin plus aztreonam. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. RCTs assessing different antibiotic regimens in late-onset neonatal sepsis with low risks of bias are warranted.

Trends in US Hospital Stays for Listeriosis in Infants

BACKGROUND AND OBJECTIVES

Although listeriosis is rare in infants, it is common for young infants with suspected serious bacterial infection to be treated empirically with agents selected, in part, for their activity against Listeria monocytogenes. Our objectives were to describe the recent epidemiology of hospital discharges for listeriosis among infants in the United States and to precisely estimate the incidence of listeriosis according to infant age and meningitis status.

METHODS

We generated national estimates for listeriosis discharges in each of the 6 years for which samples were available in the Kids' Inpatient Database during the period 1997-2012. We used random-effects models to pool descriptive information and population rates across study years.

RESULTS

The cumulative number of US hospital discharges for listeriosis in infants was 344 (95% confidence interval [CI]: 290-397) over the 6 study years. The pooled annual incidence rate in infants (per 100,000 births) was 1.41 (95% CI: 1.01-1.80) after accounting for marked fluctuation in annual rates (range: 0.66-1.86; I2=79.3%). Discharges for listeriosis without meningitis were particularly rare after the first week of life. Our models predicted only 2.7 (95% CI: 1.1-4.2) and 1.8 (95% CI: 0.0-3.6) such discharges per year in infants admitted at ages 7 to 28 days and 29 to 364 days, respectively.

CONCLUSIONS

From the perspective of providing coverage against listeriosis, the routine practice of including ampicillin in the empirical treatment of febrile infants should be reevaluated for those older than 1 week without clinical evidence of meningitis.

Pharmacokinetics of antibacterial agents in the CSF of children and adolescents

The adequate management of central nervous system (CNS) infections requires that antimicrobial agents penetrate the blood-brain barrier (BBB) and achieve concentrations in the CNS adequate for eradication of the infecting pathogen. This review details the currently available literature on the pharmacokinetics (PK) of antibacterials in the CNS of children. Clinical trials affirm that the physicochemical properties of a drug remain one of the most important factors dictating penetration of antimicrobial agents into the CNS, irrespective of the population being treated (i.e. small, lipophilic drugs with low protein binding exhibit the best translocation across the BBB). These same physicochemical characteristics determine the primary disposition pathways of the drug, and by extension the magnitude and duration of circulating drug concentrations in the plasma, a second major driving force behind achievable CNS drug concentrations. Notably, these disposition pathways can be expected to change during the normal process of growth and development. Finally, CNS drug penetration is influenced by the nature and extent of the infection (i.e. the presence of meningeal inflammation). Aminoglycosides have poor CNS penetration when administered intravenously. Intrathecal gentamicin has been studied in children with more promising results, often exceeding the minimum inhibitory concentration. There are very limited data with intrathecal tobramycin in children. However, in the few patients that have been studied, the CSF concentrations were highly variable. Penicillins generally have good CNS penetration. Aqueous penicillin G reaches greater concentrations than procaine or benzathine penicillin. Concentrations remain detectable for ≥ 12 h. Of the aminopenicillins, both ampicillin and parenteral amoxicillin reach adequate CNS concentrations; however, orally administered amoxicillin resulted in much lower concentrations. Nafcillin and piperacillin are the final two penicillins with pediatric data: their penetration is erratic at best. Cephalosporins vary greatly in regard to their CSF penetration. Few first- and second-generation cephalosporins are able to reach higher CSF concentrations. Cefuroxime is the only exception and is usually avoided due to its adverse effects and slower sterilization of the CSF than third-generation agents. Ceftriaxone, cefotaxime, ceftazidime, cefixime and cefepime have been studied in children and are all able to adequately penetrate the CSF. As with penicillins, concentrations are greatest in the presence of meningeal inflammation. Meropenem and imipenem are the only carbapenems with pediatric data. Imipenem reaches higher CSF concentrations; however, meropenem is preferred due to its lower incidence of seizures. Aztreonam has also demonstrated favorable penetration but only one study has been completed in children. Both chloramphenicol and sulfamethoxazole/trimethoprim (cotrimoxazole) penetrate into the CNS well; however, significant toxicities limit their use. The small size and minimal protein binding of fosfomycin contribute to its favorable CNS PK. Although rarely used, it achieves higher concentrations in the presence of inflammation and accumulation is possible. Linezolid reaches high CSF concentrations; however, more frequent dosing might be required in infants due to their increased elimination. Metronidazole also has very limited information but it demonstrated favorable results similar to adult data; CSF concentrations even exceeded plasma concentrations at certain time points. Rifampin (rifampicin) demonstrated good CNS penetration after oral administration. Vancomycin demonstrates poor CNS penetration after intravenous administration. When combined with intraventricular therapy, CNS concentrations are much greater. Of the antituberculosis agents, isoniazid, pyrazinamide and streptomycin have been studied in children. Isoniazid and pyrazinamide have favorable CSF penetration. Streptomycin appears to produce unpredictable CSF levels. No pediatric-specific data are available for clindamycin, daptomycin, macrolides, tetracyclines, and fluoroquinolones. Daptomycin, fluoroquinolones, and tetracyclines have demonstrated favorable CNS penetration in adults; however, data are limited due to their potential pediatric-specific toxicities and newness within the marketplace. Macrolides and clindamycin have demonstrated poor CNS penetration in adults and thus have not been studied in pediatrics.

Third generation cephalosporins versus conventional antibiotics for treating acute bacterial meningitis

BACKGROUND

Antibiotic therapy for suspected acute bacterial meningitis (ABM) needs to be started immediately, even before the results of cerebrospinal fluid (CSF) culture and antibiotic sensitivity are available. Immediate commencement of effective treatment using the intravenous route may reduce death and disability. Although bacterial meningitis guidelines advise the use of third generation cephalosporins, these drugs are often not available in hospitals in low income countries.

OBJECTIVES

The objective of this review was to compare the effectiveness and safety of third generation cephalosporins and conventional treatment with penicillin or ampicillin-chloramphenicol in patients with community-acquired ABM.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 1) which contains the Cochrane Acute Respiratory Infections Group Trials Register, MEDLINE (January 1966 to March 2007), and EMBASE (January 1974 to March 2007). We also searched the reference list of review articles and book chapters, and contacted experts for any unpublished trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing ceftriaxone or cefotaxime with conventional antibiotics as empirical therapy for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the study selection criteria, assessed methodological quality, and extracted data.

MAIN RESULTS

Nineteen trials that involved 1496 patients were included in the analysis. There was no heterogeneity of results among the studies in any outcome except diarrhoea. There was no statistically significant difference between the groups in the risk of death (risk difference (RD) 0%; 95% confidence interval (CI) -3% to 2%), risk of deafness (RD -4%; 95% CI -9% to 1%), or risk of treatment failure (RD -1%; 95% CI -4% to 2%). However, there were significantly decreased risks of culture positivity of CSF after 10 to 48 hours (RD -6%; 95% CI -11% to 0%) and statistically significant increases in the risk of diarrhoea between the groups (RD 8%; 95% CI 3% to 13%) with the third generation cephalosporins. The risk of neutropaenia and skin rash were not significantly different between the two groups. However, all the studies were conducted in the 1980s except three, which were reported in 1993, 1996, and 2005.

AUTHORS' CONCLUSIONS

The review shows no clinically important difference between ceftriaxone or cefotaxime and conventional antibiotics. In situations where availability or affordability is an issue, third generation cephalosporins, ampicillin-chloramphenicol combination, or chloramphenicol alone may be used as alternatives. The antimicrobial resistance pattern against various antibiotics needs to be closely monitored in low to middle income countries as well as high income countries.

Antibiotic treatment for bacterial meningitis in children in developing countries

Bacterial meningitis causes 125,000 deaths each year in infants and young children and 96% of these occur in less developed countries where up to 50% of children with this disease die and 25-50% of survivors have neurological sequelae. Although 3rd-generation cephalosporins are optimal empirical therapy for bacterial meningitis, they are unaffordable in many developing countries. The majority of children worldwide are currently treated with cheaper alternatives. This paper reviews the challenges facing clinicians treating bacterial meningitis in developing countries, highlighting the problem of changing patterns of antibiotic resistance. In particular, it details the evidence for the use of chloramphenicol and 3rd-generation cephalosporins.

Third generation cephalosporins versus conventional antibiotics for treating acute bacterial meningitis

BACKGROUND

Antibiotic therapy for suspected acute bacterial meningitis (ABM) needs to be started immediately, even before the results of cerebrospinal fluid culture and antibiotic sensitivity are available. It is not clear whether the available evidence supports the choice of third generation cephalosporins over the conventional antibiotic combination of ampicillin and chloramphenicol. Immediate institution of effective treatment through intravenous route may reduce death and disability in survivors.

OBJECTIVES

The objective of this review is to determine the effectiveness and safety of the third generation cephalosporins and conventional treatment with penicillin/ampicillin-chloramphenicol in patients with community-acquired acute bacterial meningitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2003) which contains the Cochrane Acute Respiratory Infections Group trials register, MEDLINE (January 1966 to November 2003), and EMBASE (January 1990 to November 2003). We also searched the reference list of review articles and textbook chapters and contacted experts for any unpublished trials.

SELECTION CRITERIA

Randomised controlled trials comparing ceftriaxone or cefotaxime with conventional antibiotics as empirical therapy of acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two independent reviewers applied the study selection criteria, assessed methodological quality and extracted data.

MAIN RESULTS

Eighteen trials included 993 patients in the analysis. The kappa (chance-corrected agreement) between the observers in study selection and data extraction was substantial. There was no heterogeneity of results among the studies in any outcome except diarrhoea. There was no statistically significant difference between the groups in the risk of death (risk difference -1%; 95% confidence interval (CI) -4% to +3%), risk of deafness (risk difference -4%; 95% CI -9% to +1%), risk of treatment failure (risk difference -2%; 95% CI -5% to +2%). However, there were significantly decreased risk of culture positivity of CSF after 10-48 hours (risk difference -6%; 95% CI -11% to 0%) and statistically significant increased in the risk of diarrhoea between the groups (risk difference +8%; 95% CI +3% to +13%) with the third generation cephalosporins. The risk of neutropenia and skin rash were not significantly different between the two groups. However, all the studies have been conducted in the eighties except two, which have been conducted in 1993 and 1996.

REVIEWERS' CONCLUSIONS

Although the review shows no clinically important difference between ceftriaxone or cefotaxime and conventional antibiotics, the studies are done decades ago and may not apply to current routine practice. However, in situations where ceftriaxone or cefotaxime are not available or affordable, ampicillin-chloramphenicol combination may be used as an alternative. The antimicrobial resistance pattern against various antibiotics needs to be closely monitored in developing as well as developed countries. The factors determining overuse of antibiotics in developing countries and educational interventions to limit such practice are priority area for research in developing countries.

Chloramphenicol or ceftriaxone, or both, as treatment for meningitis in developing countries?

AIMS

To determine in children with meningitis whether there is any difference in mortality and neurological sequelae using chloramphenicol as first line treatment, with a change to ceftriaxone if chloramphenicol resistance is shown in vitro, compared to using ceftriaxone as first line treatment, with a change to chloramphenicol if there is no evidence of in vitro resistance.

METHODS

An observational study with a retrospective control group nested within a randomised trial of fluid management for bacterial meningitis where clinical care was standardised. Chloramphenicol is standard treatment for bacterial meningitis in Papua New Guinea. In the first 150 cases we used chloramphenicol and only changed treatment to ceftriaxone if chloramphenicol resistance for cerebrospinal fluid isolates was proved. After finding 20% of Haemophilus influenzae were resistant to chloramphenicol, and that most affected children had poor outcomes, we changed to an alternative strategy. In the next 196 cases first line treatment was ceftriaxone and treatment was changed to chloramphenicol if the isolated bacteria were found to be susceptible.

RESULTS

When chloramphenicol was used as first line treatment for meningitis followed by ceftriaxone when in vitro resistance was shown, there was invariably a very poor outcome in chloramphenicol resistant disease (71% of children died or had severe neurological complications). Using ceftriaxone as first line treatment was effective in reducing mortality and neurological sequelae from chloramphenicol resistant Haemophilus influenzae type (71% v 9%, relative risk 0.13; 95% CI 0.02 to 0.87; p = 0.013). Changing to chloramphenicol if there was no evidence of in vitro resistance was less than half the cost of empirical use of ceftriaxone for a full course for all children with meningitis.

CONCLUSIONS

Using a third generation cephalosporin as first line treatment is effective in dealing with the problem of poor outcomes from meningitis due to Haemophilus influenzae that is resistant to chloramphenicol, and a strategy of changing to chloramphenicol if in vitro susceptibility is shown will reduce the use of expensive third generation cephalosporins without comprising on clinical outcomes. This highlights the urgent need to reduce the costs of third generation cephalosporins, to improve bacteriological services in developing countries, and to introduce effective and affordable vaccines against H influenzae and Streptococcus pneumoniae.

The penetration of anti-infectives into the central nervous system

The blood-brain barrier, blood-cerebrospinal fluid (CSF) barrier, and meninges are a complex and difficult-to-study system charged with protecting the central nervous system (CNS) from toxins, including drugs. Current estimates of CNS drug exposure are limited to CSF to blood ratios, of which area-under-the curve (AUC) estimates provide the most robust measure of drug exposure. Different classes of drugs and individual drugs within classes have different CNS penetration potential that is dependent upon a variety of biologic and pharmacologic factors. Clinical data (AUC and point ratios) regarding the penetration of several anti-infective agents used for the treatment of CNS infections are provided in this article.

In vitro antibiotic sensitivity pattern of common bacterial isolates from cases of acute bacterial meningitis with special reference to ceftriaxone

Ceftriaxone (RO 13-9904) has only recently been introduced in Benghazi and many parts of the word. We determined its in-vitro antibacterial activity against the primary aetiological agents of childhood meningitis in Benghazi, that included eighteen (23.3%) strains of H. influenzae, 17 (22.1%) of Str. pneumoniae and 1 (1.3%) of N. meningitidis isolated from 77 cases of acute purulent meningitis above the age of neonatal period. All strains of H. influenzae. Str. pneumoniae and N. meningitidis were sensitive to ceftriaxone and showed wide zones of inhibition by the disc diffusion technique of Kirby-Bauer. Ampicillin and chloramphenicol resistance was observed for H. influenzae (23% and 11% respectively), and Str. pneumoniae (12% and 0% respectively), in addition, 18% of strains of Str. pneumoniae showed resistance to penicillin. The broad spectrum activity of ceftriaxone has been confirmed for our locality and this finding, together with its exceptionally long half-life, excellent penetration into the C.S.F. and ease of administration (single daily dose) warrants it as the drug of choice in empherical treatment of cases of acute bacterial meningitis in children in Benghazi and in cases where resistance to ampicillin and chloramphenicol are found on subsequent testing.

Bactericidal activity of cefotaxime, desacetylcefotaxime, rifampin, and various combinations tested at cerebrospinal fluid levels against penicillin-resistant Streptococcus pneumoniae

Penicillin resistance is increasingly prevalent amongst clinical isolates of Streptococcus pneumoniae. Recently, isolates resistant to the extended-spectrum cephalosporins have also begun to emerge, and combination therapy may be necessary for infection with such organisms. We have studied the activity of cefotaxime, ceftriaxone, ceftazidime, rifampin, chloramphenicol, and vancomycin against 10 S. pneumoniae strains with penicillin minimum inhibitory concentrations (MICs) ranging from 0.03-8 micrograms/ml. The bactericidal activity of cefotaxime, desacetylcefotaxime, rifampin, and combinations of these agents (cerebrospinal fluid levels) against these isolates was determined. Elevated MICs to penicillin were associated with generally twofold lower cefotaxime MICs. All strains remained susceptible to vancomycin and rifampin. The bactericidal activity of cefotaxime with or without desacetylcefotaxime was reduced by the addition of rifampin. Pneumococcal isolates with penicillin MICs of < or = 1 microgram/ml were slowly killed by cefotaxime alone or with desacetycefotaxime. At present, there is little evidence to support the addition of rifampin to cefotaxime for therapy of meningitis.

Pharmacodynamic (kinetic) considerations in the treatment of moderately severe infections with cefotaxime

Information about the pharmacodynamics of beta-lactams has accumulated rapidly over the last 20 years, and their application to cefotaxime are discussed in this review. Application of pharmacodynamics requires an integration of the pharmacokinetic and in vitro properties of the agent. Cefotaxime is similar to other beta-lactams in that it has little concentration-dependent killing and produces no postantibiotic effect against Gram-negative bacteria. However, it has a microbiologically active metabolite, deascetylcefotaxime, which can show synergy, partial synergy, or an additive effect in combination with the parent drug. More than any other technique, animal models have been able to elucidate the pharmacokinetic parameters that predict efficacy in vivo. They have shown that for beta-lactams it is the time that levels exceed the minimum inhibitory concentration (MIC) that is the most important determinant of efficacy. For bacteria to have no postantibiotic effect, plasma levels need to exceed the MIC for the whole of the dosing interval to achieve maximum killing at the site of infection. When applying these concepts as the most stringent criteria for efficacy using pharmacokinetic values from young, healthy volunteers, it can be shown that organisms with MICs of < or = 0.03 microgram/ml for a 1-g dose and 0.06 microgram/ml for a 2-g dose to achieve optimum efficacy with 12-h dosing of cefotaxime. However, two clinical studies have demonstrated trough levels much greater than would be predicted from these pharmacokinetic values, as a result of the effects of decreased renal function accompanying sepsis and older age. These studies showed that organisms with MICs < or = 1 microgram/ml for a 1-g dose or 2 micrograms/ml for a 2-g 12-h dose were covered for the whole of the dosing interval. Thus, all strains of Enterobacteriaceae and pathogenic Neisseria spp. that lack resistance mechanisms to third-generation cephalosporins would be covered using 12-h dosing schedules.

Randomised comparison of chloramphenicol, ampicillin, cefotaxime, and ceftriaxone for childhood bacterial meningitis. Finnish Study Group

In a multicentre study, 220 consecutive cases of bacterial meningitis in children older than 3 months were randomised to treatment with chloramphenicol, ampicillin (initially with chloramphenicol), cefotaxime, or ceftriaxone. The drugs were given in four equal daily doses for 7 days, except ceftriaxone which was given only once daily. 200 cases could be assessed; the causative organisms were Haemophilus influenzae type b (Hib) in 146; meningococci (Mnc) in 32; pneumococci (Pnc) in 13; and other or unknown in 9. In patients with Hib meningitis, sterilisation of the cerebrospinal fluid occurred most rapidly with ceftriaxone. Otherwise, in terms of overall clinical recovery, normalisation of laboratory indices, clinically significant adverse reactions, toxic effects, sequelae, and mortality rate, the treatment groups were very similar. However, there were 4 bacteriological failures, all in the chloramphenicol group. Also, the treatment was extended or changed in more cases in the chloramphenicol group than in the other groups. Chloramphenicol was thus inferior to the other three antimicrobials. Ampicillin is a good and cheap alternative, but there are difficulties with resistance. Easy administration tempts the use of ceftriaxone rather than cefotaxime but it causes diarrhoea. A 7-day course of ampicillin, cefotaxime, or ceftriaxone is sufficient in Hib, Mnc, or Pnc meningitis.

Cefotaxime versus penicillin-chloramphenicol in purulent meningitis: a controlled single-blind clinical trial

In a prospective, controlled, randomized single-blind clinical trial, treatment with cefotaxime (CTX) was compared with that with standard therapy (ST), which consisted of a penicillin-chloramphenicol combination with or without sulphadiazine, in 31 patients (excluding neonates) with proven bacterial meningitis. The two groups of patients were comparable in age, sex, clinical presentation and causative pathogens. The case fatality rate was 12.5% for the CTX group and 20% for the ST group, but this difference was not significant. The times taken for the cerebrospinal fluid (CSF) to become sterile and the temperature to normalize, the mean duration of treatment, complications and adverse effects were similar for the two regimens. Neurological or developmental abnormalities on follow-up were not significantly different for the two groups. It is concluded that CTX is a suitable alternative for treatment of bacterial meningitis in infants and children.

Bacterial meningitis: is there a "best" antimicrobial therapy?

The introduction of several cephalosporins into pediatric practice has provided the physician with a number of choices in the treatment of neonatal and childhood meningitis. Adequate studies are available to indicate that these new drugs are as effective as traditional treatments in terms of survival and major neurologic sequelae but it is not known whether the results are worse or better as far as the incidence of more subtle neurologic changes is concerned. The advantages of the cephalosporins in treatment of childhood meningitis are that they permit single drug therapy, the risks of drug toxicity are reduced, and the problems of penicillin-tolerant pneumococci and ampicillin/chloramphenicol-resistant H. influenzae are avoided. When used in the treatment of neonatal disease, the cephalosporins have the advantage of lower toxicity than the aminoglycosides, generally making blood drug level determinations unnecessary, and are effective against strains of bacteria that have become resistant to the latter drugs.

Cefotaxime and desacetylcefotaxime pharmacokinetics in infants and children with meningitis

The pharmacokinetics and cerebrospinal fluid (CSF) penetration of cefotaxime (Ctx) and desacetylcefotaxime (dCtx) were evaluated in 13 infants and children with meningitis after dose 6 of Ctx in a multiple-dose intermittent intravenous infusion regimen (50 mg/kg every 6 h). Model-dependent and noncompartmental pharmacokinetic parameters were determined and were found to be congruous. The disposition of both Ctx and dCtx was described adequately by a one-compartment, open model. Noncompartmental pharmacokinetic parameters are reported. The mean Ctx serum concentration at 0.25 h postinfusion was 121.2 micrograms/ml, and the mean CSF concentration at 1 h postinfusion was 6.2 micrograms/ml. The CSF/serum ratio was variable (0 to 20%), with a mean penetration of 10.1%. The mean Ctx elimination half-life, apparent steady-state volume of distribution, and total body clearance were 0.8 h, 0.361 liter/kg, and 0.289 liter/h per kg, respectively. For Ctx, 61% of the dose was excreted unchanged in the urine during the 6-h postinfusion period, and the estimated renal clearance was 0.174 liter/h per kg. No significant correlations were observed between Ctx pharmacokinetic parameters and demographic parameters. The mean peak concentration of dCtx in serum (21.6 micrograms/ml) occurred at approximately 1.5 h postinfusion, and the mean concentration in CSF at 1 h postinfusion was 5.6 micrograms/ml. The CSF/serum ratio was extremely variable (0 to 103%), and the mean penetration was 28.8%. The mean apparent elimination half-life for dCtx was 2.1 h. In infants and children with normal renal function, a 50-mg/kg dose of Ctx administered every 6 h should provide adequate concentrations in serum and CSF in the majority of patients with meningitis.