Sulbactam/ampicillin vs. chloramphenicol/ampicillin for the treatment of meningitis in infants and children

Non-corticosteroid adjuvant therapies for acute bacterial meningitis

BACKGROUND

Acute bacterial meningitis is a bacterial infection of the membranes that surround and protect the brain, known as the meninges. The primary therapy for bacterial meningitis is antibiotics and corticosteroids. Although these therapies significantly improve outcomes, bacterial meningitis still has a high risk of death and a high risk of neurological sequelae in survivors. New adjuvant therapies are needed to further reduce the risk of death and neurological sequelae in bacterial meningitis.

OBJECTIVES

To assess the effects of non-corticosteroid adjuvant pharmacological therapies for mortality, hearing loss, and other neurological sequelae in people with acute bacterial meningitis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and LILACS databases and ClinicalTrials.gov and WHO ICTRP trials registers up to 30 September 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of any pharmacological adjuvant therapy for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed and extracted data on methods, participants, interventions, and outcomes. We assessed risk of bias of studies with the Cochrane risk of bias tool and the certainty of the evidence using the GRADE approach. We presented results using risk ratios (RR) and 95% confidence intervals (CI) when meta-analysis was possible. All other results are presented in a narrative synthesis.

MAIN RESULTS

We found that five different adjuvant therapies have been tested in RCTs for bacterial meningitis. These include paracetamol (3 studies, 1274 participants who were children); immunoglobulins (2 studies, 49 participants; one study included children, and the other adults); heparin (1 study, 15 participants who were adults); pentoxifylline (1 study, 57 participants who were children); and a mixture of succinic acid, inosine, nicotinamide, and riboflavin mononucleotide (1 study, 30 participants who were children). Paracetamol may make little or no difference to mortality (paracetamol 35.2% versus placebo 37.4%, 95% CI 30.3% to 40.8%; RR 0.94, 95% CI 0.81 to 1.09; 3 studies, 1274 participants; I² = 0%; low certainty evidence); hearing loss (RR 1.04, 95% CI 0.80 to 1.34; 2 studies, 901 participants; I² = 0%; low certainty evidence); neurological sequelae other than hearing loss (RR 1.56, 95% CI 0.98 to 2.50; 3 studies, 1274 participants; I² = 60%; low certainty evidence); and severe hearing loss (RR 0.96, 95% CI 0.67 to 1.36; 2 studies, 901 participants; I² = 0%; low certainty evidence). Paracetamol may lead to slightly more short-term neurological sequelae other than hearing loss (RR 1.99, 95% CI 1.40 to 2.81; 2 studies, 1096 participants; I² = 0%; low certainty evidence) and slightly more long-term neurological sequelae other than hearing loss (RR 2.32, 95% CI 1.34 to 4.04; 2 studies, 901 participants; I² = 0%; low certainty evidence). No adverse events were reported in either group in any of the paracetamol studies (very low certainty evidence). Two paracetamol studies had a low risk of bias in most domains, and one had low or unclear risk of bias in all domains. We judged the certainty of evidence to be low for mortality due to limitations in study design (unclear risk of bias in at least one domain and imprecision (high level of uncertainty in absolute effects), and low for all other outcomes due to limitations in study design (unclear risk of bias in at least one domain), and imprecision (low sample size and few events) or inconsistency in effect estimates (heterogeneity). We were not able to perform meta-analysis for any of the other adjuvant therapies due to the limited number of included studies. It is uncertain whether immunoglobulins, heparin, or pentoxifylline improves mortality outcomes due to the very low certainty of the evidence. Zero adverse events were reported for immunoglobulins (very low certainty evidence), and allergic reactions occurred at a rate of 3.3% in participants receiving a mixture of succinic acid, inosine, nicotinamide, and riboflavin mononucleotide (intervention group) (very low certainty evidence). None of our other outcomes (hearing loss, neurological sequelae other than hearing loss, severe hearing loss, and short-term or long-term neurological sequelae other than hearing loss) were reported in these studies, and all of these studies were judged to have a high risk of bias. All reported outcomes for all included adjuvant therapies, other than paracetamol, were graded as very low certainty of evidence due to limitations in study design (unclear or high risk of bias in at least four domains) and imprecision (extremely low sample size and few events).

AUTHORS' CONCLUSIONS

Few adjuvant therapies for bacterial meningitis have been tested in RCTs. Paracetamol may make little or no difference to mortality, with a high level of uncertainty in the absolute effects (low certainty evidence). Paracetamol may make little or no difference to hearing loss, neurological sequelae other than hearing loss, and severe hearing loss (all low certainty evidence). Paracetamol may lead to slightly more short-term and long-term neurological sequelae other than hearing loss (both outcomes low certainty evidence). There is insufficient evidence to determine whether any of the adjuvant therapies included in this review (paracetamol, immunoglobulins, heparin, pentoxifylline, or a mixture of succinic acid, inosine, nicotinamide, and riboflavin mononucleotide) are beneficial or detrimental in acute bacterial meningitis.

The effect of antibiotic exposure on eicosanoid generation from arachidonic acid and gene expression in a primitive chordate, Branchiostoma belcheri

•

Chloramphenicol treatment induced immunosuppression and severe tissue damage in amphioxus.

•

KEGG clustering showed that chloramphenicol and ampicillin treatment resulted in immunostimulation.

•

Chloramphenicol treatment induced a ∼3-fold decrease of eicosanoid levels.

•

Chloramphenicol and ampicillin treatment resulted in a 1.7-fold increase of eicosanoid levels.

•

Eicosanoids derived from arachidonic acid provide insights into the effect of chloramphenicol treatment.

Chloramphenicol (Chl) is an effective antimicrobial agent widely used in veterinary medicine and commonly used in fish. Its use is restricted in the clinic because of adverse effects on the immune system and oxidative stress in mammals. However, the effects of Chl treatment on invertebrates remain unclear. Amphioxus, a basal chordate, is an ideal model to study the origin and evolution of the vertebrate immune system as it has a primary vertebrate-like arachidonic acid (AA) metabolic system. Here, we combined transcriptomic and lipidomic approaches to investigate the immune system and observe the oxygenated metabolites of AA to address the antibiotic effects on amphioxus. Tissue necrosis of the gill slits occurred in the Chl-treated amphioxus, but fewer epithelial cells were lost when treated with both Chl and ampicillin (Amp). The immune related pathways were dysregulated in both of the antibiotic treatment groups. The Chl alone treatment resulted in immunosuppression with down-regulation of the innate immune genes. In contrast, the Chl + Amp treatment resulted in immunostimulation to some extent, as shown by KEGG clustering. Furthermore, Chl induced a 3-fold reduction in the level of the eicosanoids, while the Chl + Amp treatment resulted in 1.7-fold increase of eicosanoid level. Thus in amphioxus, Amp might relieve the effects of the Chl-induced immune suppression and increase the level of eicosanoids from AA. Finally, the oxygenated metabolites from AA might be crucial to evaluate the effects of Chl treatment in animals.

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.

Antibacterial agents in pediatrics

Antibiotics are among the most widely prescribed therapeutic agents in children. Several new trends in antibiotic usage for pediatric care have emerged. New mechanisms of antibacterial resistance have required a broader repertoire of antibiotic usage, including new agents directed at multidrug resistance. After promotion of judicious antibiotic use, there has been a decline in the number of pediatric prescriptions for antibiotics. Recent legislation addresses the necessity for pediatric clinical drug trials, ensuring development of further antibacterial agents for use in pediatric patients.

Experience with ampicillin/sulbactam in severe infections

The emergence of beta-lactamase-mediated resistance to established beta-lactam antibiotics prompted the development of beta-lactamase inhibitors for co-administration. Ampicillin has been combined with sulbactam for both parenteral and oral (as the mutual pro-drug sultamicillin) administration. The combination is active in vitro against a wide variety of Gram-positive and Gram-negative pathogens, including aerobic and anaerobic organisms. In clinical trials, ampicillin/sulbactam has proved clinically and bacteriologically effective against a variety of frequently encountered pediatric infections, including mild-to-moderate upper respiratory tract infections (acute otitis media, sinusitis, pharyngitis, and tonsillitis), severe post-operative and intra-abdominal infections, periorbital infections (which, left untreated, can lead to blindness, brain abscess, or death), acute epiglottitis, bacterial meningitis, and brain abscess. Ampicillin/sulbactam has also proved effective in the prevention of post-operative surgical infections in pediatric patients. The clinical efficacy profile of ampicillin/sulbactam and sultamicillin, combined with their excellent tolerability profile, make these agents attractive options for the management of many life-threatening infections in pediatric patients.

Claims of equivalence in randomized controlled trials of the treatment of bacterial meningitis in children

OBJECTIVE

To evaluate claims of therapeutic equivalence in studies of the treatment of bacterial meningitis in children.

METHODS

We performed a systematic review of randomized controlled trials of antimicrobial therapy for bacterial meningitis in children indexed in MEDLINE and published after 1980 and that claimed equivalency. The sample size of each trial was compared with the minimum sample size needed to rigorously claim equivalence. The primary endpoint was case fatality.

RESULTS

Twenty-five studies were identified that met the inclusion criteria. Two of these were specifically designed to test equivalence, and the remaining based claims of equivalence on failed tests of superiority. The majority of these trials (24 of 25) that claimed equivalence had sufficient sample size to exclude a 20% difference in mortality between the tested therapies. Only 3 of the 25 trials could exclude a 10% difference in mortality.

CONCLUSION

Few of the trials in this study had sufficient sample size to claim equivalence within 10% of the expected mortality. Proving equivalency is challenging because large sample sizes are often needed to ensure adequate statistical power to rule out clinically important differences between the standard of care and new therapies.

Nontraditional dosing of ampicillin-sulbactam for multidrug-resistant Acinetobacter baumannii meningitis

A 52-year-old man was admitted to a local hospital with headache, nausea, vomiting, dizziness, photophobia, and confusion after a sudden fall. Progressive changes in neurologic function were noted despite neurosurgical intervention and broad-spectrum antimicrobial coverage. Cerebral spinal fluid (CSF) culture identified Acinetobacter baumannii that was resistant to traditionally recommended therapies of amikacin and imipenem-cilastatin. The organism demonstrated minimum inhibitory concentrations of greater than 32 microg/ml and 8 microg/ml, respectively, for these two agents. Ampicillin 2 g-sulbactam 1 g every 3 hours was administered based on history of therapeutic failure of traditional dosing in our thermal injury population. Repeat CSF cultures after 12 days of ampicillin-sulbactam therapy were negative. After 35 days, the patient's A. baumannii infection was completely resolved. The patient experienced no adverse drug events or toxicity with this high-dosage regimen.

Use of ampicillin/sulbactam and sultamicillin in pediatric infections: a re-evaluation

Ampicillin/sulbactam is an effective solution to the emergence of beta-lactamase-mediated resistance among common pediatric pathogens, and is a widely recognized treatment option for a variety of pediatric infections. Recent antimicrobial surveillance data confirm the continued susceptibility of many Gram-positive and Gram-negative aerobes and anaerobes to ampicillin/sulbactam. Pharmacokinetic studies have demonstrated high drug concentrations at a variety of infection sites, including cerebrospinal fluid and bone. Furthermore, clinical studies have shown that ampicillin/sulbactam, administered intravenously, intramuscularly or orally (as the mutual prodrug sultamicillin), is clinically and bacteriologically effective against upper and lower respiratory tract infections, urinary tract infections, skin, bone and soft-tissue infections, and meningitis, and provides effective surgical prophylaxis. Sultamicillin has an excellent tolerability profile, which is associated with a low rate of treatment discontinuation. Accordingly, ampicillin/sulbactam and sultamicillin should be considered first-choice options for the management of a variety of pediatric infections.

Use of ampicillin-sulbactam for treatment of experimental meningitis caused by a beta-lactamase-producing strain of Escherichia coli K-1

We evaluated the pharmacokinetics and therapeutic efficacy of ampicillin combined with sulbactam in a rabbit model of meningitis due to a beta-lactamase-producing strain of Escherichia coli K-1. Ceftriaxone was used as a comparison drug. The MIC and MBC were 32 and greater than 64 micrograms/ml (ampicillin), greater than 256 and greater than 256 micrograms/ml (sulbactam), 2.0 and 4.0 micrograms/ml (ampicillin-sulbactam [2:1 ratio, ampicillin concentration]) and 0.125 and 0.25 micrograms/ml (ceftriaxone). All antibiotics were given by intravenous bolus injection in a number of dosing regimens. Ampicillin and sulbactam achieved high concentrations in cerebrospinal fluid (CSF) with higher dose regimens, but only moderate bactericidal activity compared with that of ceftriaxone was obtained. CSF bacterial titers were reduced by 0.6 +/- 0.3 log10 CFU/ml/h with the highest ampicillin-sulbactam dose used (500 and 500 mg/kg of body weight, two doses). This was similar to the bactericidal activity achieved by low-dose ceftriaxone (10 mg/kg), while a higher ceftriaxone dose (100 mg/kg) produced a significant increase in bactericidal activity (1.1 +/- 0.4 log10 CFU/ml/h). It appears that ampicillin-sulbactam, despite favorable CSF pharmacokinetics in animals with meningitis, may be of limited value in the treatment of difficult-to-treat beta-lactamase-producing bacteria, against which the combination shows only moderate in vitro activity.

Susceptibility of Haemophilus influenzae type b to ampicillin-sulbactam

Seventy-five strains of Haemophilus influenzae type b, including 45 beta-lactamase-positive strains, were tested by MIC and time kill studies for susceptibility to ampicillin-sulbactam at various ratios. beta-Lactamase-negative strains were inhibited by lower concentrations of ampicillin-sulbactam than beta-lactamase-positive organisms. beta-Lactamase-negative strains showed a decrease in CFU per milliliter by a factor of 10(4) after a 24-h incubation with ampicillin-sulbactam. beta-Lactamase-positive isolates showed an initial decrease by a factor of up to 10(2) CFU per milliliter, but by the end of incubation these isolates grew to approximately the same cell density as the antibiotic-free control regardless of ampicillin-sulbactam ratios. Caution should be exercised in the use of this combination in treatment of meningitis, in which a high bacterial density is commonly encountered.

Sulbactam/ampicillin, a new beta-lactamase inhibitor/beta-lactam antibiotic combination

Sulbactam/ampicillin is a combination of a beta-lactamase inhibitor with minimal intrinsic antibacterial activity (sulbactam sodium), and an aminopenicillin (ampicillin sodium). The addition of sulbactam to ampicillin has no effect on the chemical stability of ampicillin in aqueous solution, and the administration guidelines of the combination are the same as for ampicillin alone. Sulbactam acts primarily by irreversible inactivation of beta-lactamases from most beta-lactamase-producing organisms. The pharmacokinetics of sulbactam are similar to those of ampicillin with an elimination half-life of about one hour in most patients. One difference is that serum and tissue concentrations of sulbactam are usually twice those of ampicillin, at equivalent doses. The sulbactam/ampicillin combination has been approved for the treatment of adults with intraabdominal, skin and skin structure, and gynecological infections due to beta-lactamase-producing bacteria such as Staphylococcus aureus, Escherichia coli, and species of Klebsiella and Bacteroides. Clinical studies to date have also shown the combination to be effective for the treatment of meningitis, pneumonia, gonorrhea, epiglottis, urinary tract infections, cervical adenitis, and as prophylaxis for abdominal and gynecological surgeries. Many of these studies, however, have included small numbers of patients and/or had design flaws. Adverse effects have been minor with most being attributed to the ampicillin component. Sulbactam/ampicillin compares favorably with other antibiotic regimens in terms of acquisition costs and ease of administration.

Beta-lactamase inhibitors from laboratory to clinic

beta-Lactamases constitute the major defense mechanism of pathogenic bacteria against beta-lactam antibiotics. When the beta-lactam ring of this antibiotic class is hydrolyzed, antimicrobial activity is destroyed. Although beta-lactamases have been identified with clinical failures for over 40 years, enzymes with various abilities to hydrolyze specific penicillins or cephalosporins are appearing more frequently in clinical isolates. One approach to counteracting this resistance mechanism has been through the development of beta-lactamase inactivators. beta-Lactamase inhibitors include clavulanic acid and sulbactam, molecules with minimal antibiotic activity. However, when combined with safe and efficacious penicillins or cephalosporins, these inhibitors can serve to protect the familiar beta-lactam antibiotics from hydrolysis by penicillinases or broad-spectrum beta-lactamases. Both of these molecules eventually inactivate the target enzymes permanently. Although clavulanic acid exhibits more potent inhibitory activity than sulbactam, especially against the TEM-type broad-spectrum beta-lactamases, the spectrum of inhibitory activities are very similar. Neither of these inhibitors acts as a good inhibitor of the cephalosporinases. Clavulanic acid has been most frequently combined with amoxicillin in the orally active Augmentin and with ticarcillin in the parenteral beta-lactam combination Timentin. Sulbactam has been used primarily to protect ampicillin from enzymatic hydrolysis. Sulbactam has been used either in the orally absorbed prodrug form as sultamicillin or as the injectable combination ampicillin-sulbactam. Synergy has been demonstrated for these combinations for most members of the Enterobacteriaceae, although those organisms that produce cephalosporinases are not well inhibited. Synergy has also been observed for Neisseria gonorrhoeae, Haemophilus influenzae, penicillinase-producing Staphylococcus aureus, and anaerobic organisms. These antibiotic combinations have been used clinically to treat urinary tract infections, bone and soft-tissue infections, gonorrhea, respiratory infections, and otitis media. Gastrointestinal side effects have been reported for Augmentin and sultamicillin; most side effects with these agents have been mild. Although combination therapy with beta-lactamase inactivators has been used successfully, the problem of resistance development to two agents must be considered. Induction of cephalosporinases can occur with clavulanic acid. Permeability mutants could arise, especially with added pressure from a second beta-lactam.(ABSTRACT TRUNCATED AT 250 WORDS)

Penetration of sulbactam and ampicillin into cerebrospinal fluid of infants and young children with meningitis

Infusions of 50 mg of sulbactam per kg per day and 400 mg of ampicillin per kg per day in divided doses to infants and children with bacterial meningitis produced levels in cerebrospinal fluid approximately one-third those in serum. Concentrations in cerebrospinal fluid of 5.5 micrograms of sulbactam per ml and 16.0 micrograms of ampicillin per ml declined within a few days of therapy to 1.9 microgram of sulbactam per ml and 5.2 micrograms of ampicillin per ml.

Sulbactam/ampicillin. A review of its antibacterial activity, pharmacokinetic properties, and therapeutic use

Sulbactam is a semisynthetic beta-lactamase inhibitor which when combined with certain beta-lactam antibacterials extends their activity against bacteria that are normally resistant to the antibiotic due to production of beta-lactamases. In combination with ampicillin it extends the antibacterial activity of ampicillin to include beta-lactamase-producing strains which are otherwise resistant, including Bacteroides fragilis, and increases the susceptibility of many sensitive strains. Sulbactam is poorly absorbed after oral administration and sulbactam/ampicillin is therefore administered parenterally, although another linked sulbactam-ampicillin compound, sultamicillin, has been developed which is well absorbed after oral administration. The basic pharmacokinetic characteristics of sulbactam after parenteral administration are similar to those of ampicillin. Multiple-dose therapy with sulbactam/ampicillin is clinically and bacteriologically effective in infections of the urinary tract, skin and soft tissue, bones and joints, respiratory tract, ears, nose and throat, as well as intra-abdominal and obstetric and gynaecological infections and septicaemia. In addition, single intramuscular doses of sulbactam/ampicillin administered with oral probenecid are therapeutically effective in gonorrhoea, including infections due to penicillinase-producing and/or ampicillin-resistant Neisseria gonorrhoeae. In the prophylaxis of infectious complications of surgery sulbactam/ampicillin is superior to placebo and appears to be similar in efficacy to several alternative antibacterial regimens. Further studies involving larger numbers of patients are needed to clarify the comparative therapeutic and prophylactic efficacy of sulbactam/ampicillin and alternative antibacterial drugs. Nonetheless, sulbactam/ampicillin improves the therapeutic and prophylactic efficacy of an antibacterial of familiar safety, and must be seen as a worthwhile advance.