The Rate of Nasal and Oral Colonization and Expression Levels of Hyphal Adhesin Als3p and mecA Genes in Methicillin-Resistant Staphylococcus aureus and Candida spp. Isolated From Patients With Lung Cancer

 Patients with cancer is considered highly susceptible group to both nosocomial and community-acquired infections.

 In the present research, we aimed to determine the rate of nasal and oral colonization and expression level of Als3p and mecA genes among Candida spp. and methicillin-resistant Staphylococcus aureus (MRSA) in co-colonization and single colonization conditions.

 In total, 110 oral swab samples and 110 nasal swab samples were gathered from patients with lung cancer. The frequency of MRSA isolates (oxacillin-resistant Staphylococcus aureus) was determined using the disk diffusion method. In addition, the frequency and expression levels of Als3p and mecA genes among MRSA and Candida spp. isolates were determined and compared using PCR and qRT-PCR methods, respectively.

 Candida spp. and S. aureus were found in 42.7% (n=47/110), and 9.1% (n=10/110) of oral samples, respectively, while Candida spp. and S. aureus were found in 5.5% (n=6/110) and 16.4% (n=18/110) of nasal samples, respectively. Additionally, 55.5% (n=10/18) of S. aureus isolates obtained from nasal samples were MRSA. Candida albicans (n=23/110; 20.9%) had the highest frequency among Candida species. In all MRSA and Candida spp. isolates, the Als3p and mecA gene expression increased two and three times in co-colonization condition compared to single colonization condition, respectively.

 The present study revealed that co-colonization has a synergistic effect on the expression level of mecA and Als3p genes. Our finding suggested that co-colonization can facilitate the invasion of S. aureus and leads to systemic and severe infections in co-colonized patients.