Costa E M, Silva S, Tavaria F K, Pintado M M
CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Porto, Portugal.
J Appl Microbiol. 2017 Jun;122(6):1547-1557. doi: 10.1111/jam.13457. Epub 2017 May 3.
Chitosan is a natural compound that has been validated as a viable antimicrobial agent against Staphylococcus aureus. With this work we sought to evaluate the planktonic and sessile sensitivity of methicillin-resistant S. aureus to chitosan's activity and evaluate if methicillin-resistant S. aureus (MRSA) would be more or less sensitive to chitosan's activity than methicillin-sensitive S. aureus (MSSA).
A group comprised of reference strains and clinical multiresistant isolates of MSSA and MRSA were used. Methicilin resistance effect upon chitosan activity was assessed in planktonic setting and in different phases of sessile colonization, namely adhesion, biofilm formation and mature biofilm through biomass and metabolism inhibition. The results obtained showed that S. aureus methicillin resistance mechanism did not impair chitosan's activity as the highest bacterial susceptibility was registered for MRSA. Chitosan was highly effective in inhibiting MSSA and MRSA strains in both planktonic and sessile settings with biofilm inhibition percentages reaching as high as 90% for MRSA.
Staphylococcus aureus methicillin resistance did not impair chitosan's antimicrobial and antibiofilm activities and MRSA and MSSA were inhibited both in planktonic and sessile settings at low concentrations with great efficacy.
Considering the obtained results chitosan shows potential as an alternative for the control of biofilm-related recalcitrant MRSA infections.
壳聚糖是一种天然化合物，已被证实是一种对金黄色葡萄球菌有效的抗菌剂。通过这项研究，我们试图评估耐甲氧西林金黄色葡萄球菌对壳聚糖活性的浮游和固着敏感性，并评估耐甲氧西林金黄色葡萄球菌（MRSA）对壳聚糖活性的敏感性是否高于或低于甲氧西林敏感金黄色葡萄球菌（MSSA）。
使用了一组由MSSA和MRSA的参考菌株以及临床多耐药分离株组成的菌株。通过抑制生物量和代谢，在浮游环境以及固着定殖的不同阶段，即粘附、生物膜形成和成熟生物膜阶段，评估甲氧西林耐药对壳聚糖活性的影响。获得的结果表明，金黄色葡萄球菌的甲氧西林耐药机制并未损害壳聚糖的活性，因为MRSA的细菌敏感性最高。壳聚糖在浮游和固着环境中均能高效抑制MSSA和MRSA菌株，MRSA的生物膜抑制率高达90%。
金黄色葡萄球菌的甲氧西林耐药性并未损害壳聚糖的抗菌和抗生物膜活性，低浓度的壳聚糖在浮游和固着环境中均能高效抑制MRSA和MSSA。
考虑到所获得的结果，壳聚糖显示出作为控制与生物膜相关的顽固性MRSA感染的替代物的潜力。
