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Concentrations of antimicrobial agents in middle ear fluid, saliva and tears
Insights
Antibiotic levels in middle ear fluid (MEF) were high enough to treat common bacteria in children with persistent ear effusions. Saliva and tear concentrations did not reliably predict MEF levels.
Area of Science:
- Pediatric Otolaryngology
- Pharmacokinetics
- Infectious Diseases
Background:
- Persistent middle ear effusions (MEE) are common in children.
- Effective antibiotic delivery to middle ear fluid (MEF) is crucial for treatment.
- Understanding antibiotic concentrations in MEF is key for optimizing therapy.
Purpose of the Study:
- To measure antibiotic concentrations in MEF, saliva, and tears in children with persistent MEE.
- To compare MEF antibiotic levels to minimal inhibitory concentrations (MICs) for common otitis media pathogens.
- To assess the relationship between antibiotic concentrations in different bodily fluids.
Main Methods:
- Children with persistent MEE undergoing tympanostomy tube placement were studied.
- Antibiotic concentrations (cefaclor, penicillin V, amoxicillin, etc.) were measured in MEF, serum, saliva, and tears.
- Pharmacokinetic analysis was performed at various time points post-dose.
Main Results:
- Mean MEF antibiotic concentrations were several-fold greater than pneumococcal MICs.
- Trimethoprim and cefaclor concentrations exceeded MICs for Haemophilus influenzae.
- Antibiotic levels in saliva and tears did not correlate consistently with MEF concentrations.
- MEF concentrations in persistent effusions were similar to those in acute otitis media.
Conclusions:
- Antibiotic concentrations achieved in MEF are generally adequate for treating common bacterial pathogens in persistent MEE.
- Saliva and tear concentrations are not reliable indicators of MEF antibiotic levels.
- These findings support the use of systemic antibiotics for persistent MEE.
Abstract:
Antibiotics concentrations in middle ear fluid (MEF), saliva and tears were measured in children with persistent middle ear effusions undergoing tympanostomy tube placement. In 31 children given cefaclor, specimens of serum, saliva and MEF were collected at 0.5, 1, 2, 3 or 5 h after a dose. Another group of 37 children were randomized to receive a single dose of penicillin V, amoxicillin, ampicillin, erythromycin estolate, erythromycin ethylsuccinate, trimethoprim-sulfamethoxazole or cefaclor. Concentrations of antibiotics in saliva and tears bore no consistent relationship to those in MEF. Mean concentrations of all drugs in MEF were several-fold greater than the usual minimal inhibitory concentrations (MIC) of pneumococci, but only with trimethoprim and cefaclor were they greater than in usual MIC's for Haemophilus influenzae. Concentrations of antibiotics in MEF in persistent effusions were comparable to those previously reported in acute purulent effusions.