The role of bacterial toxins in sudden infant death syndrome (SIDS).

There is increasing evidence for the involvement of bacterial toxins in some cases of sudden infant death syndrome (SIDS), particularly the pyrogenic toxins of Staphylococcus aureus. This had led to the hypothesis that some SIDS deaths are due to induction of inflammatory mediators by infectious agents or their products during a period in which the infant is unable to control these normally protective responses. The genetic, developmental and environmental risk factors identified for SIDS are assessed in relation to frequency or density of mucosal colonisation by toxigenic bacteria and their effects on induction and control of inflammatory responses to the toxins.

Detection and toxin production of Staphylococcus aureus in sudden infant death cases in Hungary.

The potential role of microbial agents was investigated in 13 cases of Sudden Infant Death Syndrome and in 9 non-SIDS cases in Budapest between September 1996 and May 1998. Autopsy, histological examination and microbiological tests were performed on samples of blood, cerebrospinal fluid, pharyngeal samples and lung tissue from infants under one year died suddenly, without previous diseases. The multifactorial pathomechanism of SIDS was suggested by the isolation of toxin producing Staphylococcus aureus-, Enterobacteriaceae and Candida albicans strains in large number and by the detection of Parainfluenza Type 2 virus antigen. S. aureus proved the predominant bacteria in the SIDS cases. Nasopharyngeal microbial flora and S. aureus carrier of 100 age matched healthy infants were tested during the same period. S. aureus was isolated from 54% of SIDS cases and 37% from healthy infants /OR = 1.986 (95% Confidence interval = 0.55-7.33), p = 0243/. The enterotoxin and TSST-1 toxin producing activity of S. aureus showed the characteristic difference. The toxigenic S. aureus was detected in 46% of SIDS cases and 16% of healthy infants /OR = 4.5 (95% CI = 1.15-17.72), p = 0.010/. The distribution of toxigenic and nontoxigenic isolates was 86% in SIDS cases and 43% in healthy infants /OR = 7.875 (CI = 0.78-191.89), p = 0.041/.

Potential role of microbiological agents in sudden infant death syndrome.

The potential role of microbiological agents was investigated in 10 cases of Sudden Infant Death Syndrome in Budapest between September 1996 and December 1997. Autopsy, histological examination and microbiological tests were performed on samples of blood, cerebrospinal fluid, pharyngeal and bronchial samples from infants under six months died suddenly, without previous diseases. The multifactorial pathomechanism of SIDS was suggested by detection of Parainfluenza Type virus antigen, isolation of toxin producing Staphylococcus aureus, Enterobacteriaceae and Candida albicans strains in large number of more samples of the same infant.

A new selective method for isolation of Haemophilus species.

Chocolate agar with teicoplanin disk (30 micrograms) was used for the isolation of Haemophilus strains. Fifty strains of 3 Haemophilus species grew as well in the inhibition zones of teicoplanin disks as on teicoplanin containing selective plates, whereas Gram-positive bacteria failed to form colonies. This selective method proved especially advantageous when Haemophilus strains were isolated from mixed bacterial cultures of 665 specimens.

The role of Propionibacterium propionicus in chronic canaliculitis.

Delicate branching filaments, and cocci or rods, were seen by microscopic examination in the pus of the canaliculus lacrimalis in patients with chronic canaliculitis. Propionibacterium propionicus and different bacteria were cultivated and identified in the pus. After i.p. inoculation of mice with the Propionibacterium strains, the morphological changes characteristic of this microorganism were observed in the peritoneum, in the spleen and in the lung, giving an adequate explanation of the direct microscopic findings in the pus.

[Sensitivity of Hemophilus strains to fluoroquinolones]. / Haemophilus törzsek fluorokinolonok iránti érzékenysége.

The sensitivity of haemophilus strains isolated from patients freshly were tested by newly produced fluorokinolones with broader antimicrobial activity and excellent pharmacokinetic features. We found a high sensitivity of all haemophilus strains tested by ofloxacin with Resistest method. The minimal inhibitory concentrations in Levinthal bouillon medium ranged between 0,015-0,03 micrograms/ml and the exerted a bactericidal effect. Since these concentrations are only a small portion of the blood and tissue levels of the ofloxacin, therefore the fluorokinolones proved to be effective antibacterial drugs in the therapy of the haemophilus infections.

Histamine production by Haemophilus.

Eight Haemophilus influenzae and four Haemophilus parainfluenzae strains, all freshly isolated from patients, were examined for histamine production. Histamine was produced by all the H. influenzae (0.06 microgram-2.6 micrograms/100 ml) and by two of the H. parainfluenzae strains (46.5-47.9 micrograms/100 ml). It is concluded that histamine which plays an important role in the pathogenesis of chronic aspecific respiratory diseases, may derive not only from degranulation of mast cells, but also produced by Haemophilus.

Diffusion of metronidazole through the dentinal tubules of extracted teeth.

Passing of metronidazole from the root canal of extracted gangrenous teeth through the dentinal tubules was proved by agar diffusion and minimum inhibitory concentration assay. The findings explain the excellent clinical experience with metronidazole in root treatment.

Respiratory effect of Haemophilus influenzae endotoxin in mice.

The effect of the endotoxin of a noncapsulated Haemophilus influenzae strain isolated from bronchitis was studied on the respiration of mice. Inhalation of the H. influenzae endotoxin resulted in heavy attacks of dyspnoea with non-specific histological changes in the lung. The endotoxin elicited no direct response in isolated organs, but produced cytotoxic changes in HEp-2 tissue cultures. The experiments led to the conclusion that the clinical signs and the histological changes may be explained by the direct damaging effect of endotoxin on the cells and by the released mediator substances.

Effect of irradiated haemophilus influenzae endotoxin preparations in mice.

A detoxified substance (rdLPS) was produced from Haemophilus influenzae endotoxin by ionizing radiation and its capacity to prevent attacks of dyspnoea elicited by endotoxin inhalation in mice has been studied. The rdLPS proved to be an effective stimulant of aspecific immune resistance of mice but it could only partly prevent attacks of dyspnoea.

New selective medium for the isolation of Haemophilus species.

Chocolate agar containing lincomycin (5 micrograms/ml) was used for the isolation of haemophilus strains. One-hundred haemophilus strains of 3 species grew well on selective plates, whereas Gram-positive bacterial failed to form colonies on them. The selective culture proved especially advantageous when throat swabs were examined.

Haemophilus paraphrophilus isolated from endocarditis.

Isolation and microbiological features of a Haemophilus paraphrophilus strain which caused a subacute bacterial endocarditis are described. The isolate conformed to the first description by ZINNEMANN et al., except that it was sensitive to ampicillin.

Reisolation and characterization of Haemophilus influenzae-murium.

Twenty-three Haemophilus influenzae-murium strains were isolated from the nasopharynx of healthy CFLP white mice. Microbiological characterization of the cultures confirmed the taxonomic position of the organisms which had become problematic due to the loss of the original isolates. The type strain proposed, EO1, is available from the Hungarian National Collection of Medical Bacteria, National Institute of Public Health, Budapest as 95001.