Susceptibility pattern among pathogenic species of Aspergillus to physical and chemical treatments.
Physical treatments, like heating or irradiation, may reduce the viability or eradicate Aspergillus conidia, which in turn might help to prevent infections by members of this genus. Chemical treatments can also prevent infection resulting from contaminated hospital fabrics or surfaces. Our objectives were to study the kinetics of survival of the conidia of pathogenic Aspergillus species, like A. fumigatus, A. flavus and A. niger, during exposure to heating at 60 degrees C and microwave irradiation. In addition, we evaluated the susceptibility patterns of Aspergillus conidia to such chemical agents as cupric sulphate and sodium hypochlorite. Heating the conidia of A. flavus and A. niger at 60 degrees C for 45 min was found to be fungicidal (reduction > 104 conidia/ml), but was not with A. fumigatus conidia. Short periods of microwave irradiation (40 s) resulted in a significant reduction of the viability of the conidia of these three Aspergillus species as a result of lethal membrane lesions. All Aspergillus species were similarly susceptible to cupric sulphate and sodium hypochlorite. Therefore, heating, microwave and the chemical treatments tested impaired significantly the viability of Aspergillus conidia, supporting the use of these methods as preventive measures among patients at risk.
Araujo
Ricardo
R
Department of Microbiology, Faculty of Medicine, University of Porto, Alameda Prof Hernani Monteiro, Porto, Portugal. ricjparaujo@yahoo.com
Gonçalves Rodrigues
Acacio
A
Pina-Vaz
Cidalia
C
D001228:Aspergillosis / Q000382:microbiology; D001230:Aspergillus / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects*; D002462:Cell Membrane / Q000528:radiation effects; D019327:Copper Sulfate / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology*; D006358:Hot Temperature; D006801:Humans; D008826:Microbial Sensitivity Tests; D008872:Microwaves; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D013045:Species Specificity; D013997:Time Factors
D004202:Disinfectants; D012973:Sodium Hypochlorite; D019327:Copper Sulfate