The Oomycete Pythium oligandrum Can Suppress and Kill the Causative Agents of Dermatophytoses

Pythium oligandrum (Oomycota) is known for its strong mycoparasitism against more than 50 fungal and oomycete species. However, the ability of this oomycete to suppress and kill the causal agents of dermatophytoses is yet to be studied. We provide a complex study of the interactions between P. oligandrum and dermatophytes representing all species dominating in the developed countries. We assessed its biocidal potential by performing growth tests, on both solid and liquid cultivation media and by conducting a pilot clinical study. In addition, we studied the molecular background of mycoparasitism using expression profiles of genes responsible for the attack on the side of P. oligandrum and the stress response on the side of Microsporum canis. We showed that dermatophytes are efficiently suppressed or killed by P. oligandrum in the artificial conditions of cultivations media between 48 and 72 h after first contact. Significant intra- and interspecies variability was noted. Of the 69 patients included in the acute regimen study, symptoms were completely eliminated in 79% of the patients suffering from foot odour, hyperhidrosis disappeared in 67% of cases, clinical signs of dermatomycoses could no longer be observed in 83% of patients, and 15% of persons were relieved of symptoms of onychomycosis. Our investigations provide clear evidence that the oomycete is able to recognize and kill dermatophytes using recognition mechanisms that resemble those described in oomycetes attacking fungi infecting plants, albeit with some notable differences.

Infective endocarditis caused by unusual gram-positive pathogens

Of a total of 81 patients hospitalized in the infectious diseases department in 1990-2000 with infectious endocarditis caused by Gram-positive pathogen, unusual etiological agents were found in several cases: Streptococcus pyogenes, Streptococcus pneumoniae, Corynebacterium diphtheriae, and Gemella morbillorum. Cardiac defects were present in the latter two patients: bicuspid aortic valve and tetralogy of Fallot. Two patients were successfully treated with antibiotics only and one patient with antibiotics and surgery. The patient with C. diphtheriae endocarditis died due to progressive sepsis and multiple organ failure.

[Comparison of various methods of hemoculture tests]

Three methods of blood cultivation were compared: collection of blood into transport bottles containing only dextran-sulphate, collection into cultivation media containing bottles (aerobic, anaerobic and paediatric Dulab) and the semi-automatic continuous blood culture system (Bactec 9000, using aerobic, anaerobic and paediatric bottles). A total amount of 1.250 blood samples collected from 626 patients was divided equally into the compared bottles and processed parallelly. The yield of the Bactec aerobic bottles was significantly higher than the yield of the transport bottles and aerobic Dulab bottles (p < 0.001). However, this result was influenced by the higher rate of contaminating bacteria isolated from the aerobic Bactec bottles. The yield of the aerobic Dulab bottles was higher than the yield of the transport bottles (p < 0.01). The average time needed for the detection of microorganisms in the Bactec bottles was by 24 hours shorter than in the transport bottles and by 19 hours shorter than in the aerobic Dulab bottles (p < 0.001). The difference between the yields of the anaerobic and the paediatric bottles in our study was not significant. The time needed for the detection of microorganisms was by 17 hours shorter in the anaerobic Bactec bottles than in the transport bottles (p < 0.05).