In vitro biofilm formation by Staphylococcus aureus isolated from wounds of hospital-admitted patients and their association with antimicrobial resistance

International Journal of General Medicine Dovepress open access to scientific and medical research O r igi n a l R e s e a r c h International Journal of General Medicine downloaded from https://www.dovepress.com/ by 213.32.48.132 on 13-Jul-2018 For personal use only. Open Access Full Text Article In vitro biofilm formation by Staphylococcus aureus isolated from wounds of hospital-admitted patients and their association with antimicrobial resistance This article was published in the following Dove Press journal: International Journal of General Medicine Puja Neopane 1,2 Hari Prasad Nepal 3 Rojeet Shrestha 4 Osamu Uehara 5 Yoshihiro Abiko 2 1 Department of Microbiology, Chitwan Medical College and Teaching Hospital, Bharatpur, Nepal; 2Division of Oral Medicine and Pathology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Japan; 3Department of Microbiology, Trinity School of Medicine, Kingstown, St. Vincent and the Grenadines; 4School of Medicine, Washington University of Barbados, St. Philip, Barbados; 5Division of Disease Control and Molecular Epidemiology, Department of Oral Growth and Development, Health Sciences University of Hokkaido, Tobetsu, Japan Introduction: Staphylococcus aureus including methicillin-resistant S. aureus (MRSA) has the propensity to form biofilms, and causes significant mortality and morbidity in the patients with wounds. Our aim was to study the in vitro biofilm-forming ability of S. aureus isolated from wounds of hospitalized patients and their association with antimicrobial resistance. Materials and methods: Forty-three clinical isolates of S. aureus were obtained from 150 pus samples using standard microbiological techniques. Biofilm formation in these isolates was detected by tissue culture plate (TCP) method and tube adherence method (TM). Antimicrobial susceptibility test was performed using the modified Kirby–Bauer disk diffusion method as per Clinical and Laboratory Standards Institute guidelines. MRSA was detected using the cefoxitin disk test. Results: Biofilm formation was observed in 30 (69.8%) and 28 (65.1%) isolates of S. aureus via TCP method and TM, respectively. Biofilm-producing S. aureus exhibited a higher incidence of antimicrobial resistance when compared with the biofilm nonproducers (P<0.05). Importantly, 86.7% of biofilm-producing S. aureus were multidrug resistant (MDR), whereas all the biofilm nonproducers were non-MDR (P<0.05). Large proportions (43.3%) of biofilm producers were identified as MRSA; however, none of the biofilm nonproducers were found to be MRSA (P<0.05). Conclusion: Both the in vitro methods showed that S. aureus isolated from wound infection of hospitalized patients have high degree of biofilm-forming ability. Biofilm-producing strains have very high tendency to exhibit antimicrobial resistance, multidrug resistance and methicillin resistance. Regular surveillance of biofilm formation by S. aureus and their antimicrobial resistance profile may lead to the early treatment of the wound infection. Keywords: biofilm, multidrug resistant, methicillin-resistant Staphylococcus aureus Introduction Correspondence: Yoshihiro Abiko Division of Oral Medicine and Pathology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido, 061-0293, Japan Tel +81 133 23 1211 Fax +81 133 23 1390 Email 25 submit your manuscript | www.dovepress.com International Journal of General Medicine 2018:11 25–32 Dovepress © 2018 Neopane et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms. php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). http://dx.doi.org/10.2147/IJGM.S153268 Powered by TCPDF (www.tcpdf.org) Biofilms are the aggregation of bacteria embedded in a self-produced extracellular matrix of exopolysaccharides (EPSs), proteins and some micromolecules such as DNA. They can form on both biotic and abiotic surfaces.1 Studies have confirmed using scanning electron microscopy and other molecular techniques that wounds are colonized by biofilms.2,3 Biofilm protects the microorganism from host defenses and impedes delivery of antibiotics which may cause impairment in wound healing.4,5 Staphylococcus aureus is an opportunistic pathogen implicated as the most common agent of skin and soft tissue infections. It exists in the nasopharynx, skin, eye, intestine Dovepress International Journal of General Medicine downloaded from https://www.dovepress.com/ by 213.32.48.132 on 13-Jul-2018 For personal use only. Neopane et al and urogenital tract as normal flora. However, it can breach the skin barriers through the wound or surgical incision and cause infection. Furthermore, it has the ability to adhere to and form a biofilm on tissues or medical indwelling devices. S. aureus initially adheres to a solid substrate, after which cell–cell adhesion occurs; the bacteria then multiply to form a multilayered biofilm encased in EPS. In fact, biofilm formation involves the production of polysaccharide intercellular adhesin,6 which depends on the expression of the intercellular adhesion (IcaADBC) operon that encodes three membrane proteins (IcaA, IcaD and IcaC) and one extracellular protein (IcaB).7 In addition, several surface proteins have been involved in the biofilm formation process, including biofilm-associated protein,8 S. aureus surface protein G,9 fibronectin-binding proteins or staphylococcal protein A.10 Biofilm formation by S. aureus can lead to a delay in reepithelialization of the infected tissues, ultimately increasing healing time. S. aureus biofilms have been associated with chronic wounds like diabetic foot ulcer, pressure sores and venous ulcers.3 Detachment of matured biofilm of S. aureus is a prerequisite for the dissemination of wound infection.11 Methicillin-resistant S. aureus (MRSA) poses a great risk to patients with wounds; significant increase in both mortality and morbidity in humans has been reported in patients infected with MRSA due to the development of biofilms.12 MRSA are frequently resistant to a wide variety of antibiotics, and this is more pronounced in those having ability to form a biofilm. The S. aureus infections and biofilm formations, in addition to an increase in the length of hospital stay, are associated with more clinically important pathologies such as pneumonia, polyarthritis, necrotizing fas (...truncated)