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Inside the Operating Theatre
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Manoj Ramachandran, Steve Key, Alan White
Antiseptics are disinfectants used in living tissue. Their use results in a reduction in the number of viable organisms but not the complete destruction of all viable micro-organisms; unlike the process of sterilization, some viruses and bacterial spores may remain. Three solutions are commonly used for hand washing and skin antisepsis prior to surgery: Iodophors: iodine complexed with solubilizing agent, such as povidone, resulting in free iodine release when in solution. They are potent, broad-spectrum and rapidacting bactericidal agents, also active against spores, fungi and viruses, but inactivated by blood, faeces and pus. They work through the destruction of microbial proteins and deoxyribonucleic acid (DNA). They may be irritant and cause hypersensitivity reactions. In aqueous form, they are safe on open wounds and mucous membranes.Alcohols: used in 70% concentration, rapidly active against a broad spectrum of gram-negative and gram-positive bacteria. They have some antiviral activity but are relatively inactive against spores and fungi. They work by evaporation and protein denaturation, but have no residual activity. Use on open wounds and mucous membranes is contraindicated.Chlorhexidine: a bisbiguanide compound with bactericidal and bacteriostatic activity against a broad spectrum of gram-positive and gram-negative bacteria, fungi, and lipophilic viruses. It acts through membrane disruption. It is deactivated by many topical skin products, cleansers and hand sanitizers; it is active in the presence of blood, soap and pus, but its effectiveness may be reduced. Use on mucous membranes or in body cavities is contraindicated. Pseudomonas may grow in stored contaminated solutions.
Tolerance to disinfectants (chlorhexidine and isopropanol) and its association with antibiotic resistance in clinically-related Klebsiella pneumoniae isolates
Published in Pathogens and Global Health, 2021
Jasmine Morante, Antonio M. Quispe, Barbara Ymaña, Jeel Moya-Salazar, Néstor Luque, Gabriela Soza, María Ramos Chirinos, Maria J Pons
Biocides are routinely used in healthcare settings and play an essential role in infection control [1], one that has been highlighted during the fight against SARS-CoV-2. Two of the most frequently used types of biocides in hospitals are chlorhexidine digluconate (CHG) and isopropyl alcohol (ISP). Chlorhexidine is a bisbiguanide antiseptic used against a wide range of microorganisms. It functions by forming a bridge between phospholipids with subsequent displacement of cations (Mg2+ and Ca2+) [2], resulting in membrane disruption via a reduction in the capacity of the bacterial membrane to osmoregulate and changes in enzymes associated with metabolic membrane capability [2]. Chlorhexidine is often used for procedures such as handwashing, preoperative preparation, and surface disinfection because of its bacteriostatic and bactericidal properties [3,4], as well as its ability to rapidly denature the proteins of microorganisms [5].
Effects of a sub-minimum inhibitory concentration of chlorhexidine gluconate on the development of in vitro multi-species biofilms
Published in Biofouling, 2020
Yuki Suzuki, Tatsuya Ohsumi, Toshihito Isono, Ryoko Nagata, Taisuke Hasegawa, Shoji Takenaka, Yutaka Terao, Yuichiro Noiri
In order to control the growth of cariogenic biofilms, the application of antimicrobial agents, such as chlorhexidine gluconate (CHG) and essential oils, has been widely adopted (Sreenivasan and Gaffar 2002). CHG is a cationic bisbiguanide that involves a broad spectrum of antibacterial activity. It has been proved to be a safe and stable substance that is effective in reducing the viability of biofilm-forming bacteria (Jones 1997; Van Strydonck et al. 2012). The main function of such antimicrobial agents is bactericidal in nature (Koo and Jeon 2009). Antibiotics are effective agents against bacterial pathogens when their concentrations are higher than the minimum inhibitory concentration (MIC). However, the use of bactericidal agents can lead to a disruption in the resident microflora and the establishment of exogenous species, which can result in pathological changes (Marsh 1992). Therefore, a chemotherapeutic approach aimed at reducing the growth and virulence properties of bacteria in antibiotic concentrations below the MIC, which is defined as sub-minimum inhibitory concentrations (sub-MIC), was investigated.
Catechol-modified chitosan hydrogel containing PLGA microspheres loaded with triclosan and chlorhexidine: a sustained-release antibacterial system for urinary catheters
Published in Pharmaceutical Development and Technology, 2022
Chengxiong Lin, Zhengyu Huang, Tingting Wu, Weikang Xu, Ruifang Zhao, Xinting Zhou, Zhibiao Xu
Samples 1–5 represent the control group, Chi-C coating, Chi-C/TCS microsphere coating, Chi-C/CHX microsphere coating, and Chi-C/TCS + CHX microsphere coating, which are introduced in Section 2.4. As the most common bacteria found in CAUTI, the antibacterial effects of various samples on Proteus mirabilis (gram-negative bacterium) and Staphylococcus aureus (gram-positive bacterium) appear to be particularly important. CHX is a cationic bisbiguanide which has a low mammalian toxicity. It is bacteriostatic at low concentrations and bactericidal at high concentrations, depending on the bacteria species. Due to its affinity for negatively charged bacterial cell surfaces, the method of action includes the breakdown of the cytoplasmic membrane (Jones CG 1997; Singha et al. 2017). As a contrast, TCS is a broad-spectrum antimicrobial agent and it is bacteriostatic by inhibiting fatty acid synthesis at low concentrations and becomes biocidal by targeting bacterial membranes and cytoplasm at low concentrations (Hiraku et al. 2004). In order to measure the combined bacteriostatic mechanism of CHX and TCS on bacteria, the sample 5 had two types of microspheres in antibacterial experiment. As shown in Figures 6 and 7, pure Chi-C coating and silicon rubber have no bacteriostatic function. For the first seven days, the Chi-C/TCS shows better antibacterial performance on Proteus mirabilis and Staphylococcus aureus, while the colony gradually increases with the increasing co-culture days. It means that resistance of both two bacteria emerge and the susceptibility to TCS gradually decreases, which matched the results of Jones GL et al. (2006) and Fisher et al. (2015). As a contrast, Chi-C/CHX system (sample 4) and Chi-C/TCS + CHX system (sample 5) present better antibacterial performance for Staphylococcus aureus after two weeks. For Proteus mirabilis, sample 4 shows a small number of colonies for the first three days and sample 5 emerges certain colonies at 10 days. There are no bacterial colonies in 15 days. On one hand, TCS microspheres were degraded quickly than CHX microspheres and TCS shows stable antibacterial activity at first day. On the other hand, it shows that the susceptibility to CHX is stronger than TCS after 15 days. The mixed microsphere of TCS and CHX show more stable antibacterial properties for entire experiment period.