treatment and prevention of otitis media

In Vivo Evaluation of Cefuroxime Axetil-Loaded Bioadhesive Nanoparticles to Treat Haemophilus influenzae-Induced Otitis Media

Otitis media (OM) is a common disease in children. One of the most common pathogens causing OM is non-typeable Haemophilus influenzae (NTHi). NTHi in the middle ear can be successfully eradicated by a regimen of oral antibiotics sustained for 7–10 days (e.g., cefuroxime axetil 250 mg/day for patients aged 3 months to 2 years and 500 mg/day for patients ages ≥2 years). However, lack of compliance is relevant to treatment failure or early relapse. In order to overcome these challenges, we have developed antibiotics-loaded bioadhesive nanoparticles (BNPs) that can adhere to the epidermis of the middle ear after local administration and significantly prolong the release time of antibiotics in the middle ear. Compared with oral administration of CA, local delivery of free antibiotic cefuroxime axetil (CA), and CA loaded non-bioadhesive nanoparticles (CA/NNPs), BNPs loaded with cefuroxime axetil (CA/BNPs) showed significantly longer retention time in the middle ear, resulting in continuous release of the drug and higher therapeutic efficacy against OM with only a single dosage. CA concentrations were maintained above the minimum inhibitory concentration (MIC) for NTHi throughout 7 days’ treatment. NTHi OM in a mouse model was successfully eradicated without causing tissue toxicity. CA/BNPs minimize systemic drug exposure through local administration, as demonstrated by undetectable levels in the blood.

Pneumococcal polysaccharide protein D-conjugate vaccine (Synflorix; PHiD-CV)

The pneumococcal polysaccharide protein D-conjugate vaccine (PHiD-CV; Synflorix) contains ten capsular polysaccharide serotypes from the bacterium Streptococcus pneumoniae, eight of which are conjugated to a nonlipidated cell-surface liporotein (protein D) of non-typeable Haemophilus influenzae (NTHi) and two of which are conjugated to either tetanus or diphtheria toxoid. In a three-dose primary vaccination schedule in infants aged <6 months, PHiD-CV elicited high immune responses against all pneumococcal serotypes contained in the vaccine and was noninferior to an approved 7-valent pneumococcal conjugate vaccine (7vCRM) for eight of the ten serotypes (five of the seven common to both vaccines). Moreover, functional antibodies were elicited against all vaccine serotypes in an opsonophagocytic activity (OPA) assay. A fourth booster dose of PHiD-CV during the second year of life elicited an anamnestic response against all ten pneumococcal serotypes, as determined by both antibody concentrations and OPA titers. There were no clinically relevant changes in the immunogenicity of PHiD-CV when coadministered with meningococcal serogroup C conjugate or pentavalent whole cell pertussis combination vaccines, and polio vaccines using two different primary vaccination schedules. 11Pn-PD, an 11-valent prototype of PHiD-CV, demonstrated protection against episodes of acute otitis media (AOM) caused by S. pneumoniae and NTHi in infants aged <27 months. The first occurrence of an episode of AOM caused by pneumococcal vaccine serotypes was reduced by 52.6% in 11Pn-PD vaccinees compared with recipients of a control vaccine (primary endpoint). The tolerability profile of PHiD-CV was generally similar to that of 7vCRM.

Cefdinir: a review of its use in the management of mild-to-moderate bacterial infections

Cefdinir (Omnicef) is an oral third-generation cephalosporin with good in vitro activity against many pathogens commonly causative in community-acquired infections. The drug provides good coverage against Haemophilus influenzae, Moraxella catarrhalis and penicillin-susceptible Streptococcus pneumoniae, the most common respiratory tract pathogens. Cefdinir is stable to hydrolysis by commonly occurring plasmid-mediated beta-lactamases and retains good activity against beta-lactamase-producing strains of H. influenzae and M. catarrhalis. The drug distributes into various tissues (e.g. sinus and tonsil) and fluids (e.g. middle ear), and has a pharmacokinetic profile that allows for once- or twice-daily administration.Cefdinir, administered for 5 or 10 days, has shown good clinical and bacteriological efficacy in the treatment of a wide range of mild-to-moderate infections of the respiratory tract and skin in adults, adolescents and paediatric patients in randomised, controlled trials. In adults and adolescents, cefdinir is an effective treatment for both lower (acute bacterial exacerbations of chronic bronchitis [ABECB], community-acquired pneumonia) and upper (acute bacterial rhinosinusitis, streptococcal pharyngitis) respiratory tract infections, and uncomplicated skin infections. Its bacteriological and clinical efficacy in patients with lower respiratory tract infections was equivalent to that of comparator agents (cefprozil [bacteriological only], loracarbef, cefuroxime axetil and cefaclor). In one trial in patients with ABECB, cefdinir produced a higher rate of clinical cure than cefprozil (95% CIs indicated nonequivalence). Cefdinir also produced good clinical and bacteriological responses equivalent to responses with amoxicillin/clavulanic acid in patients with acute bacterial rhinosinusitis. In addition, it was at least as effective as penicillin V (phenoxymethylpenicillin) in streptococcal pharyngitis/tonsillitis and as effective as cefalexin in uncomplicated skin infections. In paediatric patients aged > or =6 months, cefdinir showed similar efficacy to that of amoxicillin/clavulanic acid or cefprozil in acute otitis media, and cefalexin in uncomplicated skin infections. Cefdinir given for 5 or 10 days was at least as effective as penicillin V for 10 days in patients with streptococcal pharyngitis/tonsillitis. Cefdinir is usually well tolerated. Diarrhoea was the most common adverse event in trials in all age groups. Although the incidence of diarrhoea in cefdinir recipients was generally higher than in adults and adolescents treated with comparators, discontinuation rates due to adverse events were generally similar for cefdinir and comparator groups. In conclusion, cefdinir is a third-generation cephalosporin with a broad spectrum of antibacterial activity encompassing pathogens that are commonly causative in infections of the respiratory tract or skin and skin structure. Depending on the infection being treated, cefdinir can be administered as a convenient once- or twice-daily 5- or 10-day regimen. Clinical evidence indicates that cefdinir is an effective and generally well tolerated drug with superior taste over comparator antibacterial agents and is therefore a good option for the treatment of adults, adolescents and paediatric patients with specific mild-to-moderate respiratory tract or skin infections, particularly in areas where beta-lactamase-mediated resistance among common community-acquired pathogens is a concern.

Short-course antimicrobial therapy of respiratory tract infections

Accumulating evidence suggests that short-course (</=5 days, </=3 days for azithromycin) antimicrobial therapy may be at least as effective as and, in some cases, may be more effective than traditional longer (10- to 14-day) therapies. In group A beta-haemolytic streptococcal tonsillopharyngitis, short-course therapy with 6 days of amoxicillin, 4-5 days of a variety of cephalosporins and 5 days of clarithromycin modified-release and telithromycin are all reasonable alternatives to traditional 10-day penicillin therapy. Short-course (i.e. 3-day) azithromycin therapy is not recommended because of suboptimal clinical and bacteriological results compared with penicillin therapy, unless the dosage is doubled from 10 to 20 mg/kg/day for all 3 days. In uncomplicated acute suppurative otitis media, single-dose intramuscular ceftriaxone or 3- to 5-day short-course oral antimicrobial therapy should be effective in the majority (>/=80%) of patients. However, more research is clearly needed in the subpopulations of children <2 years of age and in those with unresponsive/recurrent disease, since short-course therapy may not be successful in the majority of these patients. In sinusitis, most short-course therapy data have involved maxillary disease in adult patients. Regimens have included 3 days of azithromycin or cotrimoxazole (trimethoprim/sulfamethoxazole) or 5 days of cefpodoxime, telithromycin, gatifloxacin, gemifloxacin or amoxicillin/clavulanic acid. Preliminary results are encouraging but more study is clearly needed, especially in the paediatric population. In acute bacterial exacerbations of chronic bronchitis, short-course therapy with a variety of cephalosporins, second-generation fluoroquinolones and advanced generation macrolides/azalides/ketolides are all reasonable alternatives to traditional 7- to 14-day therapies. Cost containment in antimicrobial therapy should involve consideration of short-course therapy in the management of the most common types of respiratory tract infections.

Amoxicillin/clavulanic acid is ineffective at preventing otitis media in children with presumed viral upper respiratory infection: a randomized, double-blind equivalence, placebo-controlled trial

AIMS

To assess the equivalence of amoxicillin/clavulanic acid and placebo in the prevention of acute otitis media in children at high risk of acute otitis media who develop upper respiratory tract infection.

METHODS

This was a multicentre, equivalence, randomized, double-blind trial of two parallel groups comparing 5 days of amoxicillin/clavulanic acid 75 mg kg-1 day-1 (i.e. 25 mg kg-1 every 8 h) and placebo. The main outcome measure was acute otitis media occurring within 8-12 days of initiating treatment.

RESULTS

Two hundred and three infants, aged 3 months-3 years with upper respiratory tract infection over 36 h and a history of recurrent acute otitis media were included over 8.5 months. Two children were lost to follow-up. Patient characteristics were similar in both groups. In the intention to treat analysis the frequency of acute otitis media was 16.2% (16/99) in the placebo group and 9.6% (10/104) in the amoxicillin/clavulanic acid group (P = 0.288). The difference between acute otitis media rates was 6.6% (one-sided 95% confidence interval of 14.3%). The occurrence of side-effects was similar in the amoxicillin/clavulanic acid and placebo groups.

CONCLUSIONS

The difference in effectiveness between antibiotic and placebo was not greater than 14.3%, and we calculated that 94 children would need to be exposed to antibiotics to avoid six cases of acute otitis media. In view of the risk of development of resistance due to frequent exposure to antibiotics, our study supports the need for reduction in the administration of antibiotics in upper respiratory tract infection even in children at high risk of acute otitis media.

Conjugated heptavalent pneumococcal vaccine

OBJECTIVE

To review the immunogenicity, efficacy, and safety of the heptavalent conjugated pneumococcal vaccine (PCV7).

DATA SOURCES

A MEDLINE search (1993-August 2001) of research limited to humans published in the English language was conducted.

STUDY SELECTION

Findings from randomized, controlled, multicenter trials were reviewed. Literature regarding epidemiology, control, and treatment of invasive pneumococcal diseases in different populations and the Advisory Committee on Immunization Practices recommendations were also reviewed.

DATA SYNTHESIS

PCV7 administered to infants aged 2, 4, and 6 months, with a booster dose at 12-15 months, has been shown to be immunogenic. It decreases the incidence of invasive pneumococcal disease; individual data on bacteremia and meningitis are unavailable. Findings from clinical trials showed that invasive pneumococcal disease caused by vaccine serotypes was reduced by 87%, 58%, and 62% for children <1 year, <2 years, and <5 years of age, respectively, after introduction of routine vaccine use. The overall incidence of acute otitis media did not decrease significantly. However, culture-confirmed episodes and episodes due to pneumococcal serotypes included in the vaccine were reduced. The vaccine was immunogenic in children with sickle cell disease, but its efficacy in preventing invasive pneumococcal diseases remains unclear. Although immunogenicity and efficacy trials are lacking, the vaccine is recommended for Alaskan Native or American Indian children between 24 and 59 months of age, and for children with underlying conditions such as HIV infection, AIDS, other immunocompromising conditions, and chronic illnesses. At the manufacturer's list price of 58 dollars/dose, PCV7 is not projected to be cost-effective after 4 doses. Postmarketing analysis evaluating immunogenicity and efficacy in the excluded population may favorably change this.

CONCLUSIONS

Based on published efficacy and immunogenicity data, pharmacy formularies should include PCV7.