Bactericidal activity of skin disinfectants on methicillin-resistant Staphylococcus aureus

Alcohol-Based Hand Sanitizers: Does Gelling Agent Really Matter?

Hand hygiene, social distancing, and face covering are considered the first protection against Coronavirus spreading. The high demand during the COVID-19 emergency has driven a frenetic production and marketing of hand sanitizer gels. Nevertheless, the effect of the gelling agent and its amount on the effectiveness of alcohol-based hand sanitizers (ABHSs) needs to be clarified. We presented a systematic study on the effect of the characteristics and concentration of the most employed excipients on the properties and antimicrobial activity of ABHSs. Three different gelling agents, carbopol, hydroxypropylmethylcellulose (HPMC), and hydroxyethylcellulose (HEC), at four different concentrations were used to prepare ABHSs. Viscosity, spreadability, delivery from commercial dispensers, evaporation rate, rubbing time, and hand distribution of the ABHSs were then explored. Biocidal activity of selected ABHSs was evaluated in vitro on ATCC and clinical strains. The studied ABHS can be considered bioactive and comfortable. Nevertheless, the cellulose polymers and ethanol interactions led to a slight but significant reduction in the biocidal activity compared with carbopol-based formulations. Our results underline the importance of the gelling agent properties and support the choice of carbopol as one of the best thickener agents in ABHS formulations.

Skin disinfection practice before skin anaesthesia, prior to neuraxial blockade: a survey of government hospital practices in South Africa

Background: Infectious complications following neuraxial block, although being of low incidence, may lead to morbidity and mortality. Two common methods utilised for skin disinfection before skin anaesthesia prior to a neuraxial block are the isopropanol only method (isopropanol method) and the full aseptic technique (classic method). The objective of this study was to survey government-employed South African anaesthesiologists’ preference regarding the disinfection practices before the administration of local anaesthetic agents to the skin prior to the performance of a neuraxial block. Methods: Ethics approval was obtained prior to commencing the study. An electronic, web-based questionnaire in the form of a survey was distributed to various anaesthetic departments in various government teaching hospitals in South Africa. Descriptive statistics were used on the raw data using the Fisher exact test to measure associations between the different categorical variables. Results: A significant response rate of 60.3% was achieved. Regarding subarachnoid blocks, more than half of the participants (52.0%) that participated in the survey utilise the isopropanol method whereas less than half of the participants utilise the isopropanol method when performing an epidural block. Close to 75% of participants with zero to five years anaesthetic experience prefer the isopropanol method whilst only 20.9% of anaesthetists with more than ten years’ experience prefer the isopropanol method when performing a subarachnoid block (p < 0.01). Conclusion: Both methods described in this study (classic and isopropanol methods) are practised commonly by the participants in the survey and neither the classic nor the isopropanol method dominates. Local guidelines need to address the technique used to disinfect the skin before the administration of the local anaesthetic agent to the skin prior to performing a neuraxial block.

Susceptibility of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) to chlorhexidine digluconate, octenidine dihydrochloride, polyhexanide, PVP-iodine and triclosan in comparison to hospital-acquired MRSA (HA-MRSA) and community-aquired MRSA (CA-MRSA): a standardized comparison

Background

Recent publications have raised concerns of reduced susceptibilities of clinical bacterial isolates towards biocides. This study presents a comparative investigation of the susceptibility of livestock-associated Methicillin-resistant Staphylococcus aureus (LA-MRSA), hospital-acquired MRSA (HA-MRSA) and community-aquired MRSA (CA-MRSA) to the commonly used antiseptics chlorhexidine (CHX), octenidine (OCT), polyhexanide (PHMB), PVP-iodine (PVP-I) and triclosan (TCX) based on internationally accepted standards.

Methods

In total, 28 (18 LA-, 5 HA- and 5 CA) genetically characterized MRSA strains representing a broad spectrum of hosts, clonal complexes and spa-types, as well as the reference methicillin-sensitive Staphylococcus aureus (MSSA) strain ATCC 6538, were selected. Minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MBC) were determined in accordance with DIN 58940-7, 58940-8 and DIN EN ISO 20776-1. The microbicidal efficacy was determined in accordance with DIN EN 1040.

Results

Results from the MIC/MBC and quantitative suspension tests revealed differences between antiseptic substances but not between epidemiological groups of MRSA strains. OCT and PHMB were the most active substances with a minimal MIC of 1 mg/L, followed by CHX (2 mg/L), TCX (32 mg/L) and finally PVP-I (1024 mg/L). The MSSA reference strain showed a tendency to a higher susceptibility compared to the MRSA strains.

Conclusions

This investigation of the susceptibility of a range of LA-, HA- and CA-MRSA strains using standardized conditions gave no indication that LA-MRSA strains are less susceptible to commonly used antiseptics compared to HA- and CA-MRSA strains.

Lumbar tinea versicolor and spinal anaesthesia

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The risk of meningitis is very low in lumbar tinea versicolor parturient.

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Meticulous skin preparation to reduce the likelihood of infection transmission into subarachnoid space.

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Chlorhexidine 0.5% with 70% alcohol is antiseptic skin preparation.

Infection to the meningeal layer causing meningitis is one of the most feared complications of spinal anaesthesia. Anaesthetists will avoid spinal anaesthesia for those who are having skin infection at the puncture site. However in obstetric population, anaesthetist will try their best to avoid general anaesthesia due to its unwanted effects and complications. Strict and appropriate antiseptic measures such as chlorhexidine 0.5% with 70% alcohol has been suggested to reduce risk of transmission of microorganisms into subarachnoid space. We reported a parturient who had generalized tinea versicolor at the lumbar area, safely anaesthetized under spinal anaesthesia through meticulous antiseptic skin preparation who required delivery by caesarean section.

Safety guideline: skin antisepsis for central neuraxial blockade

Concise guidelines are presented that recommend the method of choice for skin antisepsis before central neuraxial blockade. The Working Party specifically considered the concentration of antiseptic agent to use and its method of application. The advice presented is based on previously published guidelines, laboratory and clinical studies, case reports, and on the known properties of antiseptic agents.

Epidural abscess after multiple lumbar punctures for labour epidural catheter placement

Epidural catheterization is routinely used by anaesthesiologists to provide labour and post-operative analgesia. In most cases, catheter placement is without serious side effects and uneventful. However, epidural abscess is a rare complication that may result in severe morbidity. We present a case of epidural abscess after labour epidural catheter placement in a healthy 36-year-old female who presented on post-partum d 10 with complaints of fever and back pain. She was treated with intravenous antibiotics and fully recovered.

Povidone-iodine: use in hand disinfection, skin preparation and antiseptic irrigation

Iodine and its antibacterial properties have been used for the prevention or management of wound infections for over 150 years. However, the use of solutions (tincture) of iodine has been replaced by the widespread use of povidone-iodine, a water-soluble compound, which is a combination of molecular iodine and polyvinylpyrrolidone. The resultant broad spectrum of antimicrobial activity is well documented and its efficacy, particularly in relation to resistant micro-organisms such as methicillin-resistant Staphylococcus aureus, has been shown. In the clinical environment, there is no general agreement regarding the 'best' antiseptic and the practice varies widely. This article reviews the studies that have assessed the efficacy of povidone-iodine in hand disinfection and skin preparation and its use as an antiseptic irrigant. Although there is a distinct lack of well-designed, randomised controlled trials evaluating antiseptic efficacy, selection should be based on the next best available evidence. This evidence suggests that the use of povidone-iodine as an agent of choice is dependent on the clinical need but is also likely to be influenced by personal preference.

Comparison of four antiseptic preparations for skin in the prevention of contamination of percutaneously drawn blood cultures: a randomized trial

A number of skin antiseptics have been used to prevent the contamination of blood cultures, but the comparative efficacies of these agents have not been extensively evaluated. We therefore sought to compare the efficacy of four skin antiseptics in preventing blood culture contamination in a randomized, crossover, investigator-blinded study conducted in an emergency department and the inpatient wards of a university hospital. The patient group included all patients from whom blood samples were obtained percutaneously for culture. Skin antisepsis was performed with 10% povidone-iodine, 70% isopropyl alcohol, tincture of iodine, or povidone-iodine with 70% ethyl alcohol (i.e., Persist). The blood culture contamination rate associated with each antiseptic was then determined. A total of 333 (2.62%) of 12,692 blood cultures were contaminated during the study period compared to 413 (3.21%) of 12,859 blood cultures obtained during the previous 12-month period (relative risk = 0.82; 95% confidence interval, 0.71 to 0.94; P = 0.006). During the study, the contamination rates were determined to be 2.93% with povidone-iodine, 2.58% with tincture of iodine, 2.50% with isopropyl alcohol, and 2.46% with Persist (P = 0.62). We detected no significant differences in the blood culture contamination rates among these four antiseptics, although there was some evidence suggesting greater efficacy among the alcohol-containing antiseptics. Among the evaluated antiseptics, isopropyl alcohol may be the optimal antiseptic for use prior to obtaining blood for culture, given its convenience, low cost, and tolerability.