Potential significance of colonization with beta-lactamase-producing Haemophilus parainfluenzae in children

Supraglottitis and Hemophilus parainfluenzae: pathogenic potential of the organism

Hemophilus parainfluenzae may be a normal inhabitant of the pharynx, but it can have pathogenic potential elsewhere in the body. It has been identified as a cause of bacteremia and meningitis. The case discussed here represents the first report of H parainfluenzae-induced supraglottitis in a child. In reviewing its pathogenic potential in the upper respiratory tract, it appears that its major effect could be the ability to transfer ampicillin resistance to ampicillin-susceptible Hemophilus influenzae.

Evaluation of beta-lactamase activity and microbial interference in treatment failures of acute streptococcal tonsillitis

Out of 169 patients with streptococcal tonsillitis treated with phenoxymethylpenicillin, 13 (8%) developed a new clinical infection with the same streptococcal strain within 2 weeks of completing the therapy (clinical treatment failure) and 24 (14%) were clinically healthy but harboured the same streptococcal strain after treatment (bacterial treatment failure). Patients with clinical treatment failure showed beta-lactamase activity in their saliva pellet significantly more often than patients with bacterial treatment failure, healed streptococcal tonsillitis or non-streptococcal tonsillitis as well as healthy controls. In an interference study, clinical treatment failures were compared with healthy streptococcal carriers, i.e. persons living in the same household and harbouring the same beta-streptococcal strain. 11/12 healthy carriers had alpha-streptococci with interfering activity against their own beta-streptococcal strain, while the corresponding figure for the clinical treatment failures was 2/13. Furthermore, 6/12 healthy carriers had beta-streptococci inhibiting their own alpha-strains, while the streptococci in 11/13 clinical treatment failures had this ability. The beta-lactamase activity and the interference between alpha- and beta-streptococci may be a contributory cause to treatment failure in streptococcal tonsillitis.

Pharmacokinetics of phenoxymethylpenicillin in tonsils

The pharmacokinetics of phenoxymethylpenicillin in tonsillar tissue was studied in 33 patients who underwent tonsillectomy, mainly because of repeated tonsillitis or peritonsillitis. The patients were operated on 30-240 min after an oral penicillin dose of 12.5 mg/kg body weight. The mean serum concentration was 2.8 micrograms/ml for 10 patients operated upon 80-95 min after drug administration. The mean tissue concentration for these patients at the same time was 0.6 micrograms/g. The mean concentration of penicillin in tissue after 240 min was 0.05 micrograms/g. 19% of the serum concentration was recovered in the tonsillar tissue. No significant difference between penicillin concentration in the centre or surface of the tonsils was found. The tissue concentration was calculated to be above 0.03 micrograms/ml for at least 4-5 h. 30% of the patients harboured penicillinase producing bacteria on their tonsils, mainly Staphylococcus aureus. These patients had a lower tissue concentration than those lacking the bacteria, but the difference was not statistically significant (p = 0.095).

Bacteremia caused by a beta-lactamase producing Haemophilus parainfluenzae strain of a new biotype. A case report

A case of Haemophilus parainfluenzae bacteremia without known infectious focus is reported. Phenotypically, the isolated strain is a typical H. parainfluenzae except for its ability to produce indole and beta-lactamase. Beta-lactamase producing H. parainfluenzae organisms are encountered occasionally, but to the best of our knowledge this is the first reported blood culture isolate with this ability. We propose a new biotype (IV) of H. parainfluenzae to accommodate strains that are indole, urease and ornithine decarboxylase positive.