Malek Namaki1, Shahram Habibzadeh2, Hamid Vaez3, Mohsen Arzanlou1, Somayeh Safarirad1, Seyed Ali Bazghandi1, Amirhossein Sahebkar4,5,6,7, Farzad Khademi8. 1. Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran. 2. Department of Infectious Diseases, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran. 3. Department of Microbiology, School of Medicine, Zabol University of Medical Sciences, Zabol, Iran. 4. Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. 5. Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran. 6. School of Medicine, The University of Western Australia, Perth, Australia. 7. School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. 8. Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran. k_farzad@yahoo.com.
Abstract
BACKGROUND: Biocides are frequently used as preservative, disinfectant and sterilizer against many microorganisms in hospitals, industry and home. However, the reduced susceptibility rate of Pseudomonas aeruginosa (P. aeruginosa) strains to biocides is increasing. The aim of this study was to evaluate the antimicrobial activity of four frequently used biocides against P. aeruginosa and to determine the prevalence of genes involved in biocide resistance. METHODS: A total of 76 clinical isolates of P. aeruginosa strains were used in the present study. The minimum inhibitory concentrations (MICs) of four biocides, i.e. chlorhexidine digluconate, benzalkonium chloride, triclosan and formaldehyde, against P. aeruginosa strains were determined using agar dilution method. In addition, the prevalence of biocide resistance genes was determined using the polymerase chain reaction (PCR) method. RESULTS: In the present study, the highest MIC90 and MIC95 (epidemiological cut-off) values were observed for benzalkonium chloride (1024 μg/mL), followed by formaldehyde (512 μg/mL), triclosan (512 μg/mL) and chlorhexidine digluconate (64 μg/mL). Furthermore, the prevalence of qacEΔ1, qacE, qacG, fabV, cepA and fabI genes were 73.7% (n = 56), 26.3% (n = 20), 11.8% (n = 9), 84.2% (n = 64), 81.5% (n = 62) and 0% (n = 0), respectively. A significant association was observed between the presence of biocide resistance genes and MICs (p < 0.05). Furthermore, there was no significant association between the presence of biocide resistance genes and antibiotic resistance (p > 0.05), except for levofloxacin and norfloxacin antibiotics and qacE and qacG genes (p < 0.05). CONCLUSION: Our results revealed that chlorhexidine digluconate is the most effective biocide against P. aeruginosa isolates in Ardabil hospitals. However, we recommend continuous monitoring of the antimicrobial activity of biocides and the prevalence of biocide-associated resistance genes for a better prevention of microorganism dissemination and infection control in hospitals.
BACKGROUND: Biocides are frequently used as preservative, disinfectant and sterilizer against many microorganisms in hospitals, industry and home. However, the reduced susceptibility rate of Pseudomonas aeruginosa (P. aeruginosa) strains to biocides is increasing. The aim of this study was to evaluate the antimicrobial activity of four frequently used biocides against P. aeruginosa and to determine the prevalence of genes involved in biocide resistance. METHODS: A total of 76 clinical isolates of P. aeruginosa strains were used in the present study. The minimum inhibitory concentrations (MICs) of four biocides, i.e. chlorhexidine digluconate, benzalkonium chloride, triclosan and formaldehyde, against P. aeruginosa strains were determined using agar dilution method. In addition, the prevalence of biocide resistance genes was determined using the polymerase chain reaction (PCR) method. RESULTS: In the present study, the highest MIC90 and MIC95 (epidemiological cut-off) values were observed for benzalkonium chloride (1024 μg/mL), followed by formaldehyde (512 μg/mL), triclosan (512 μg/mL) and chlorhexidine digluconate (64 μg/mL). Furthermore, the prevalence of qacEΔ1, qacE, qacG, fabV, cepA and fabI genes were 73.7% (n = 56), 26.3% (n = 20), 11.8% (n = 9), 84.2% (n = 64), 81.5% (n = 62) and 0% (n = 0), respectively. A significant association was observed between the presence of biocide resistance genes and MICs (p < 0.05). Furthermore, there was no significant association between the presence of biocide resistance genes and antibiotic resistance (p > 0.05), except for levofloxacin and norfloxacin antibiotics and qacE and qacG genes (p < 0.05). CONCLUSION: Our results revealed that chlorhexidine digluconate is the most effective biocide against P. aeruginosa isolates in Ardabil hospitals. However, we recommend continuous monitoring of the antimicrobial activity of biocides and the prevalence of biocide-associated resistance genes for a better prevention of microorganism dissemination and infection control in hospitals.