Molecular Identification and Virulence Gene Profiling of Aspergillus fumigatus Isolated from Feline Respiratory Infections

Abstract

Respiratory aspergillosis in felines is major problems in diagnosis and treatment, thereby leading to a high rate of morbidity. The reason for the pathogenic success of Aspergillus fumigatus lies in the presence of certain through virulence factors, which enable the pathogen to invade the host tissue and evade the host immune system. The study aimed to identify the Aspergillus fumigates isolate from respiratory infections of cats by PCR of the mitochondrial ND2 gene and virulence genes with sequencing. PCR amplification of the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene was used to verify the presence of A. fumigatus. The virulence potential of the confirmed isolates was assessed by the presence of the alkaline protease (alp1) and aspartic protease (asp) genes. The molecular study showed that the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene was used to verify the presence of A. fumigatus in 35 isolates from totally 41 phenotypically characterized isolates during  six months of sample collection period in different veterinary medicine clinics and centers in Karbala province, also the study showed that the a considerable difference in the occurrence of important protease gene sequences among the 35 feline A. fumigatus isolates, the alp1 gene that encodes alkaline protease was present in 100% (all 35) of the isolates, emphasizing the importance of this gene in the overall pathogenicity of this fungus.

However, the asp gene that encodes aspartic protease was present in only 15 (42.9%) of the isolates. DNA sequencing was performed on the isolates and give accession numbers LC915276, LC915275 and LC915273 for Mitochondrial NADH subunit 2(ND2), Alkaline protease (alp1) and Aspartic protease (asp) respectively. The sequences were then submitted to the NCBI GenBank database to ensure that a genetic fingerprint existed in the public domain.

These findings highlight on the importance of molecular diagnosis of feline aspergillosis and reveal important virulence gene repertoire, which suggests that although alp1 is a key gene, asp might play a role in the pathogenicity of a subset of A. fumigatus strains in cats.