Geraldes Catarina, Verdial Cláudia, Cunha Eva, Almeida Virgílio, Tavares Luís, Oliveira Manuela, Gil Solange
Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477 Lisboa, Portugal.
Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477 Lisboa, Portugal.
Antibiotics (Basel). 2021 May 27;10(6):639. doi: 10.3390/antibiotics10060639.
Hospital-acquired infections (HAIs) are a rising problem worldwide, and the best way of coping with them is through infection tracking and surveillance systems, combined with prevention strategies, namely efficient disinfection protocols, that employ various biocides. However, increasing reports about reductions in biocide susceptibility and the development of cross-resistance to antimicrobials emphasize the need for identifying the factors influencing biocide efficiency. In this study, 29 bacterial isolates ( = 3 , = 2 spp., = 23 spp., and = 1 ), obtained from environmental samples collected from the Biological Isolation and Containment Unit (BICU), of the Veterinary Teaching Hospital of the Faculty of Veterinary Medicine, University of Lisbon, were tested in order to determine their antimicrobial susceptibility to various antibiotics. Thirteen of these isolates were further selected in order to determine their antimicrobial susceptibility to Virkon™ S, with and without the presence of organic matter. Afterward, seven of these isolates were incubated in the presence of sub-lethal concentrations of this formulation and, subsequently, new susceptibility profiles were determined. Fourteen of the 29 isolates (48.3%) were classified as multidrug resistant, all previously identified as enterococci. Concerning Virkon™ S's susceptibility, the Minimal Bactericidal Concentration (MBC) of this biocide regarding all isolates was at least eight times lower than the concentration regularly used, when no organic matter was present. However, when organic matter was added, MBC values rose up to 23 times. After exposure to sub-lethal concentrations of Virkon™ S, four enterococci presented a phenotypical change regarding antimicrobial susceptibility towards gentamicin. Virkon™ S also resulted in higher MBC values, up to 1.5 times, in the presence of low concentrations of organic matter, but no rise in these values was observed in assays without interfering substance. Virkon™ S seemed to be an efficient formulation in eliminating all bacteria isolates isolated from the BICU. However, organic matter could represent a hindrance to this ability, which emphasizes the importance of sanitization before disinfection procedures. The changes seen in antimicrobial susceptibility could be explained by a general stress-induced response promoted by the sub-lethal levels of Virkon™ S. Additionally, when no organic matter was present, a decrease in susceptibility to this biocide seemed to be non-existent.
医院获得性感染（HAIs）在全球范围内是一个日益严重的问题，应对这些感染的最佳方法是通过感染跟踪和监测系统，结合预防策略，即采用各种杀菌剂的高效消毒方案。然而，关于杀菌剂敏感性降低和对抗微生物剂产生交叉耐药性的报道越来越多，这凸显了识别影响杀菌剂效率因素的必要性。在本研究中，对从里斯本大学兽医学院兽医教学医院生物隔离与遏制单元（BICU）采集的环境样本中获得的29株细菌分离株（=3株，=2株，=23株，=1株）进行了测试，以确定它们对各种抗生素的抗菌敏感性。从这些分离株中进一步选择了13株，以确定它们在有无有机物存在的情况下对Virkon™ S的抗菌敏感性。之后，将其中7株分离株在该制剂的亚致死浓度下培养，随后确定新的敏感性谱。29株分离株中有14株（48.3%）被归类为多重耐药，所有这些分离株之前都被鉴定为肠球菌。关于Virkon™ S的敏感性，当不存在有机物时，该杀菌剂对所有分离株的最低杀菌浓度（MBC）至少比常规使用浓度低8倍。然而，当添加有机物时，MBC值上升至23倍。在暴露于Virkon™ S的亚致死浓度后，4株肠球菌在对庆大霉素的抗菌敏感性方面出现了表型变化。在低浓度有机物存在的情况下，Virkon™ S也导致MBC值升高，最高可达1.5倍，但在没有干扰物质的试验中未观察到这些值的升高。Virkon™ S似乎是一种有效消除从BICU分离出的所有细菌分离株的制剂。然而，有机物可能会阻碍这种能力，这强调了在消毒程序之前进行清洁的重要性。抗菌敏感性的变化可以通过Virkon™ S的亚致死水平引发的一般应激诱导反应来解释。此外，当不存在有机物时，对这种杀菌剂的敏感性似乎不存在降低的情况。
