Biomedical subjects

E Grahn

Publications and source records attributed to E Grahn.

27 records · Page 2Linked to original sources

PubMed1987

The effect of penicillin on bacterial interference in vivo.

The study was designed to analyse the effect of penicillin on interference between alfa-streptococci and group A streptococci in vivo. Tissue cages were implanted subcutaneously in 9 rabbits and inoculated with 10(5) cfu of alfa- and beta-streptococci together as well as separately. Both streptococci were recovered 96 h after the inoculation in the untreated rabbits. Alfa-streptococci inhibiting the growth of beta-streptococci in vitro retained this capacity under the experimental in vivo conditions. Higher penicillin concentration did not increase the killing rate of beta-streptococci grown separately while a faster killing was observed with low penicillin levels in the presence of inhibiting alfa-streptococci, indicating synergistic effect.

Animals↗

PubMed1987

Penicillin tolerance in beta-streptococci isolated from patients with tonsillitis.

Beta-streptococci isolated from patients with acute tonsillitis were tested for penicillin tolerance defined as an MBC/MIC ratio greater than or equal to 16. 11/18 strains recovered from patients with clinical treatment failure were tolerant to penicillin in comparison with 0/15 strains from successfully treated patients. The MBC/MIC ratio was less than 16 for all strains versus cefadroxil but above that ratio for many strains versus clindamycin, doxycycline and erythromycin. We suggest that penicillin tolerance may be one reason to treatment failures in individuals with streptococcal tonsillitis and that other antibiotics could be used to treat these patients since penicillin tolerance is not correlated to a general increase in antibiotic resistance.

Cefadroxil↗

PubMed1987

Penicillin concentration in saliva and its influence on bacterial interference.

The aim of the investigation was to study the influence of various penicillin levels on the interference between alfa- and beta-streptococci based on antibiotic levels registered after oral intake of penicillin tablets. It was found that penicillin was released from ordinary sugar coated tablets already in the mouth resulting in concentrations in saliva above the MIC of most penicillin sensitive microorganisms during the first 2 min. This was followed by a decrease of the alfa-streptococcal flora. It was also shown that penicillin levels above the MIC of alfa-streptococci resulted in prolonged survival of beta-streptococci as compared to that noted at penicillin levels above the MIC of beta-streptococci but below that of the alfa-strains. At this latter level a synergistic effect between penicillin and interfering alfa-streptococcal strains could be demonstrated.

Administration, Oral↗

PubMed1986

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).

Adolescent↗

PubMed1986

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.

Adolescent↗

PubMed1983

Bacterial interference in the throat flora during a streptococcal tonsillitis outbreak in an apartment house area.

During an outbreak of streptococcal tonsillitis in an apartment house area the interfering capacity of alpha-hemolytic streptococci isolated from the inhabitants' throat flora on the beta-hemolytic streptococcal strains recovered during the outbreak was investigated. Strains of alpha-streptococci with an inhibiting capacity on beta-streptococci were isolated mainly from individuals seemingly resistant to streptococcal tonsillitis while patients with repeated tonsillitis often had beta-streptococcal strains inhibiting the growth of the patients own alpha-streptococcal flora. Inhibiting alpha-streptococcal strains were isolated in high frequency in healthy patients that had recently recovered from tonsillitis.

Adolescent↗

PubMed1983

Interference of alpha-hemolytic streptococci isolated from tonsillar surface on beta-hemolytic streptococci (Streptococcus pyogenes)--a methodological study.

The interference between alpha-streptococcal strains obtained from patients with repeated tonsillitis and a collection of group A streptococcal strains were studied. For this purpose three in vitro methods were designed and compared. The results obtained by a simple plating technique suitable for screening purposes were found to correlate well with those using more laborious techniques. In a limited scale some of the alpha- and beta-streptococcal combinations were tested under in vivo conditions using a tissue cage model allowing repeated sampling. In most instances agreement between the results of the in vitro and in vivo methods was registered. Several alpha-strains having inhibitory capacity to the majority of a collection of group A streptococci belonging to different serotypes were found, but also alpha-strains with an inhibitory activity restricted to few group A isolates within a certain serotype. Also beta-streptococcal strains with growth inhibiting activity towards some alpha-strains were found. As the methods were chosen to eliminate many of the unspecific inhibitory factors and the beta-hemolytic test strains showed a pattern of inhibition that varied for each of the reference alpha-strains the activity is most likely attributed to bacteriocin-like substances.

Adolescent↗

PubMed1983

Bacterial interference in streptococcal tonsillitis.

On the basis of the presented results and those published by other investigators it can be stated that in the throat (i) bacterial interference is a multifaceted phenomenon; (ii) bacterial interference not only varies individually but also fluctuates in the individual by time and the epidemiological situation; (iii) bacterial interference among the microbes in the normal flora apparently helps the individual to combat the invading microorganisms; (iv) bacteriocins, if present, in the invading bacteria represent an important virulence factor; (v) bacterial interference as a factor of the host resistance to infection can be influenced negatively by antibiotic therapy; (vi) bacterial interference can act synergistically with antibiotics given in optimal doses saving the normal flora.

Animals↗

PubMed1980

The Woronets trait: a new familial erythrocyte anomaly.

A dominantly inherited abnormality of the red blood cells is described. It is characterized by the presence of a small population of markedly distorted red blood cells resembling keratocytes. In addition, many of the red cells show minor deformities resembling the beginning stages of formation of echinocytes. Red cell lifespan is normal, and the severely deformed cells appear to represent the senescent population. Inappropriate increases in activities of some, but not all, age-dependent red cell enzymes were observed. The anomaly appeared to be entirely benign; no abnormal clinical findings were associated with this defect. It has been designated the Woronets trait.

Adolescent↗