Evaluation of a Biocide Used in the Biological Isolation and Containment Unit of a Veterinary Teaching Hospital

Abstract

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 (n = 3 E. coli, n = 2 Pseudomonas spp., n = 23 Enterococcus spp., and n = 1 Staphylococcus pseudintermedius), 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.

In Vitro Control of Multidrug-Resistant Klebsiella pneumoniae Infection by Some Biocides used in Erbil Hospitals

“…Our findings are consistent with those of prior Indian study (Chakraborty et al, 2014). Virkon is broad-spectrum disinfectant that is efficient against a wide range of viruses, bacteria and fungi (Bartlett et al, 2021) (Geraldes et al, 2021) (Tedesco et al, 2019). Virkon is an oxidizing agent with an anionic surfactant and a low pH.…”

Enterococcus Virulence and Resistant Traits Associated with Its Permanence in the Hospital Environment

“…In enterococci, such as in other bacteria, increases in tolerance to biocides could be associated to protective stress-associated mechanisms triggered when in the presence of sub-lethal concentrations of these compounds, either due to a wrongful application or to biocidal residues left in the environment after usage [ 16 ].…”

“…This overly known resistance to antibiotics is not the only trait that makes Enterococcus a threat to human and animal health. They also present a great capacity of persisting in the environment [ 11 , 12 ], which might be associated with some reports of decreased susceptibility to certain biocides [ 13 , 14 , 15 ], especially in the presence of organic matter [ 16 , 17 ]. They also have a formidable biofilm-forming capacity [ 8 ], and they are known for their genome’s plasticity, which allows them to easily acquire, conserve and disseminate genetic traits among not only enterococci, but also other Gram-positive bacteria [ 8 , 18 , 19 , 20 , 21 ].…”

In Vitro Investigation of the Antibacterial Activity of Nine Commercial Water Disinfectants, Acidifiers, and Glyceride Blends against the Most Important Poultry Zoonotic Bacteria

“…In addition, understanding how these products act against common poultry pathogens in vitro could be helpful in designing a holistic and economically viable dosage scheme for further in vivo and in-field investigations. To date, there are only a few available studies on the antimicrobial activity of commercial products [ 32 , 33 , 34 , 35 ], and the results are non-comparative due to variable examination methods, tested strains, and culture conditions [ 36 ].…”