Distribution Of Strains Of Aspergillus Superficialis Infection And Drug Susceptibility Test

Objective: There is a lack of systematic assessment of the distribution of superficial aspergillus infected strains and drug susceptibility of strains.This paper studies the differences in the distribution of superficial aspergillus infected strains and drug susceptibility of strains at different sites,then evaluates and screens the methods for the identification of superior superficial aspergillus infected strains.Method:Selecting patients with Aspergillus external auditory canal disease,Aspergillus keratopathy and Aspergillus onychomycosis from the Department of Otolaryngology,the Department of Ophthalmology,and the Department of Dermatology of the Jining NO.1 People’s Hospital and the Department of Otolaryngology of PKUCare Luzhong Hospital.Taking the secretions from external auditory canal,cornea and subxiphoid secretions to screen the Aspergillus in the initial isolation and cultivation samples.Applying ITS-Ben A-Ca M-RPB2 quadruplex gene association identification to construct phylogenetic tree method and mass spectrometer（MALDI-TOF）assay for strain identification separately.Selecting common clinical antifungal drugs to apply in vitro drug susceptibility testing on the isolated strains according to CLSI standard.Analyzing the correlation between sex,age,pathogenic area,trauma and other factors of the patients from whom the strains originated and the disease further.Result: ITS-Ben A-Ca M-RPB2 quadruplex gene association identification identified 120 Aspergillus strains under to six groups.They were Aspergillus terreus（73 cases,60.8%）,Aspergillus welwitschiae（17cases,14.2%）,Aspergillus flavus（13 cases,10.8%）,Aspergillus tubingensis（9 cases,7.5%）,Aspergillus tubingensis（9 cases,rate 7.5%）,Aspergillus fumigatus（6 cases,rate 5%）and 2 rare Aspergillus species,ranked by the amounts.MALDI-TOF identified 63 strains of species.The mass spectral identification rate of all strains was 52.5%,of which 33.3%（40 strains）were matching with the result from quadruplex gene association identification and 19.2%（23 strains）were not matching with the result from quadruplex gene association identification.Among the systemically administered drugs in the drug susceptibility testing on the isolated strains above,micafungin had the highest resistance rate（40%）,azoles had relatively high sensitive（6.7% and 3.3%,respectively）,terbinafine and amphotericin B were slightly less（10% and 11.7%,respectively）sensitive comparing to azoles.Although fluconazole can be systemically administered,it is often used as a topical formulation for the treatment of superficial aspergillus infections clinically.So,this study evaluated it as a topical agent.But fluconazole did not show antibacterial activity in this study.Natamycin has approximately the same antibacterial activity as nystatin,but there are more selections for natamycin in terms of the types and concentrations of formulations available commercially.There were no significant differences in the distribution and drug susceptibility of strains at different infection areas,and all strains were screened for 16 multi-drug resistant strains,with an overall multi-drug resistance rate of 13.3%.The clinical data reviewing indicated that the inoculation of pathogenic fungal after trauma was the major direct reason of Aspergillus infection.There was no statistically significant difference in gender distribution between the different areas of superficial aspergillus infection groups（p=0.587;p>0.05）.The average age in the different infection groups was 48.7 ± 16.3 years in the external auditory canal infection group,59.7 ± 15.7 years in the corneal infection group,and 56.4 ± 11.9 years in the nail infection group.Only the difference in age distribution between the external auditory canal infection group and the corneal infection group was statistically significant,and the corneal infection group was older than the external auditory canal infection group（p=0.03;p<0.05）.Conclusion: The target gene identification method has a higher identification rate compared with the MALDI-TOF.All strains can be identified to the species,which proofs it identify unknown fungal more accurately than MALDI-TOF.Aspergillus terreus had the highest proportion of in this study,and triazoles（except fluconazole）should be considered for systemic drug administration,and micafungin is not recommended.Fluconazole is not recommended as the primary treatment among topical medicine.And natamycin can be recommended as the primary topical medicine because of its economy and high sensitivity.This study shows superficial aspergillus infection is more common in middle-aged and elderly people,and the infection is closely related to external injury and environmental exposure.Therefore,the elderly population should be alerted to the occurrence of superficial aspergillus infection after trauma.