Evaluation of chlorhexidine and povidone iodine activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis using a surface test

Efficacy of Povidone Iodine Solution in the Prevention of Surgical Site Infections in Minimally Invasive Instrumented Spinal Fusion Surgery

STUDY DESIGN

A retrospective case-controlled study.

OBJECTIVES

To evaluate overall infection rate and adverse event after harvesting bone graft soaking and surgical wound irrigation by povidone iodine solution (PVI) in the minimally invasive instrumented spinal fusion surgery. In order to reduce the rate of surgical site infection in spinal surgery, surgical wound irrigation by povidone iodine solution has been well-established. However, the efficacy of autologous bone graft soaking by PVI has not been evaluated before.

METHODS

This is a retrospective cohort study. 120 patients were enrolled in the PVI group and compared with 124 patients in the historical cohort. In the PVI group, the harvesting autologous bone graft was soaking and the surgical wound was also irrigated by diluted PVI solution. The outcome measures were overall infection rate, superficial wound infection and deep infection. In addition, the delayed union of the fusion mass was also evaluated through the radiograph evaluation.

RESULTS

Both groups shared similar patient demographics instead of body mass index. The use of PVI solution had decreased the overall infection rate (0% versus 4.03%, p = 0.026) and deep infection rate (0% versus 3.23%, p = 0.047). In addition, there was no delayed bone healing in the PVI group after autologous bone graft soaking.

CONCLUSIONS

In this study, we conclude that harvested autologous bone graft after PVI soaking in spinal fusion surgery can decrease the incidence of deep infection.

Preoperative skin asepsis protocols using chlorhexidine versus povidone-iodine in veterinary surgery: A systematic review and meta-analysis

OBJECTIVE

To provide a systematic assessment of the efficacy of preoperative skin asepsis using chlorhexidine versus povidone-iodine based protocols for surgical site infection (SSI) prevention in veterinary surgery.

STUDY DESIGN

Systematic meta-analytical review according to PRISMA-P guidelines.

SAMPLE POPULATION

Studies comparing preoperative skin asepsis protocols using chlorhexidine versus povidone-iodine in veterinary surgery identified by systematic search between 1990 and 2020.

METHODS

A search using MEDLINE/Pubmed, Web of Science and CAB Abstracts was performed, followed by secondary searches of Google Scholar, Proquest Dissertation and Theses, and relevant bibliographic articles. Primary and secondary outcome measures were the efficacy of skin asepsis protocols using chlorhexidine versus povidone-iodine on SSI incidence and skin bacterial colonization, respectively. A meta-analysis was performed with a random-effect model, with effect size calculated as risk ratio (RR) or mean standard deviation (MSD) with 95% CI. Statistical significance was set at P < .05.

RESULTS

Among 1067 publications that met the initial search criteria, 9 relevant studies were eligible for analysis. No difference in the incidence of postoperative SSI or skin bacterial colonization between preoperative asepsis protocols using chlorhexidine versus povidone-iodine was found. Insufficient information and detail were frequent among studies and precluded a clear assessment of bias.

CONCLUSION

This study showed that asepsis protocols using chlorhexidine were comparable to povidone-iodine in preventing postoperative SSI and reducing skin bacterial colonization.

CLINICAL SIGNIFICANCE

Given the limitations of the studies that were included in terms of both quality and quantity, more high-quality randomized controlled trials are needed to confirm these conclusions.

Dilute Povidone-Iodine Irrigation Reduces the Rate of Periprosthetic Joint Infection Following Hip and Knee Arthroplasty: An Analysis of 31,331 Cases

BACKGROUND

Total joint arthroplasty (TJA) surgeons employ various strategies to reduce the risk of periprosthetic joint infection (PJI). Few studies have examined the efficacy of preclosure dilute povidone-iodine irrigation in a large cohort accounting for recent practice changes in TJA. This study compared the risk of PJI in TJA patients with and without dilute povidone-iodine irrigation.

METHODS

This is a retrospective study of all consecutive primary TJAs between 2009 and 2019 at a single institution. We included 31,331 cases, of which 8659 were irrigated with dilute povidone-iodine and 22,672 were irrigated with sterile saline prior to closure. The primary endpoint was PJI as defined by 2018 International Consensus Meeting criteria with a minimum follow-up of 1 year. Multivariate logistic regression was used to determine the association between dilute povidone-iodine irrigation and PJI while controlling for demographics, comorbidities, and operative factors.

RESULTS

In total, 340 patients (1.09%) developed PJI. Dilute povidone-iodine irrigation was associated with 2.34 times lower rate of PJI (0.6% vs 1.3%). Using multiple regression, dilute povidone-iodine remained significantly associated with a reduction in PJI. The absolute risk reduction was 0.73% and number needed to treat was 137 patients. Female gender, American Society of Anesthesiologists score, operative time, anesthesia type, prophylactic antibiotic type, and tranexamic acid were other significant factors in the regression model.

CONCLUSION

The routine use of dilute povidone-iodine could prevent 1 PJI for every 137 TJA patients, regardless of their preoperative risk. These findings support the use of povidone-iodine irrigation as a safe and cost-effective measure to reduce PJI.

Back to Basics: Choosing the Appropriate Surface Disinfectant

From viruses to bacteria, our lives are filled with exposure to germs. In built environments, exposure to infectious microorganisms and their byproducts is clearly linked to human health. In the last year, public health emergency surrounding the COVID-19 pandemic stressed the importance of having good biosafety measures and practices. To prevent infection from spreading and to maintain the barrier, disinfection and hygiene habits are crucial, especially when the microorganism can persist and survive on surfaces. Contaminated surfaces are called fomites and on them, microorganisms can survive even for months. As a consequence, fomites serve as a second reservoir and transfer pathogens between hosts. The knowledge of microorganisms, type of surface, and antimicrobial agent is fundamental to develop the best approach to sanitize fomites and to obtain good disinfection levels. Hence, this review has the purpose to briefly describe the organisms, the kind of risk associated with them, and the main classes of antimicrobials for surfaces, to help choose the right approach to prevent exposure to pathogens.

Prevention of Surgical Site Infection in Lumbar Instrumented Fusion Using a Sterile Povidone-Iodine Solution

BACKGROUND

Surgical site infection (SSI) is a well-documented complication in patients who undergo posterior spine instrumentation with most studies reporting an incidence of 1%-12%. Some studies have documented that a diluted sterile povidone-iodine (PVI) solution can be safely used in posterior spinal fusion surgeries as an antiseptic; in this study, we analyzed its effectiveness in reducing SSI.

METHODS

This retrospective study consisted of consecutive patients who underwent elective posterior lumbar instrumentation performed by a single surgeon from 2016 to 2019. In the first 134 patients, wounds were irrigated before arthrodesis and closure with 1 L of 0.9% normal saline solution; in the subsequent 144 patients, wound irrigation was with a solution of 35 mL of sterile 10% PVI. Both groups were analyzed to determine if wound irrigation with sterile PVI solution decreased SSIs.

RESULTS

There were 9 (6.7%) SSIs in the 0.9% normal saline solution group versus 1 (0.7%) SSI in the PVI group (P = 0.008). PVI solution had a relative risk for SSI of 0.093 (P = 0.008) and an adjusted odds ratio of 0.113 (P = 0.05). Increased body mass index and posterolateral spine fusion with laminectomy were significant risk factors for SSI (P = 0.04 and P = 0.030, respectively).

CONCLUSIONS

Wound irrigation with PVI solution significantly reduced SSI in elective posterior lumbar instrumentation cases. Subgroup analysis provided significant results to recommend use of PVI solution for SSI prevention, particularly in overweight and obese patients. We also recommend its use in patients with risk factors for SSI, such as longer operative time and unintended durotomy.

Povidone Iodine: Properties, Mechanisms of Action, and Role in Infection Control and Staphylococcus aureus Decolonization

Nasal decolonization is an integral part of the strategies used to control and prevent the spread of methicillin-resistant Staphylococcus aureus (MRSA) infections. The two most commonly used agents for decolonization are intranasal mupirocin 2% ointment and chlorhexidine wash, but the increasing emergence of resistance and treatment failure has underscored the need for alternative therapies. This article discusses povidone iodine (PVP-I) as an alternative decolonization agent and is based on literature reviewed during an expert’s workshop on resistance and MRSA decolonization.

Nasal decolonization is an integral part of the strategies used to control and prevent the spread of methicillin-resistant Staphylococcus aureus (MRSA) infections. The two most commonly used agents for decolonization are intranasal mupirocin 2% ointment and chlorhexidine wash, but the increasing emergence of resistance and treatment failure has underscored the need for alternative therapies. This article discusses povidone iodine (PVP-I) as an alternative decolonization agent and is based on literature reviewed during an expert’s workshop on resistance and MRSA decolonization. Compared to chlorhexidine and mupirocin, respectively, PVP-I 10 and 7.5% solutions demonstrated rapid and superior bactericidal activity against MRSA in in vitro and ex vivo studies. Notably, PVP-I 10 and 5% solutions were also active against both chlorhexidine-resistant and mupirocin-resistant strains, respectively. Unlike chlorhexidine and mupirocin, available reports have not observed a link between PVP-I and the induction of bacterial resistance or cross-resistance to antiseptics and antibiotics. These preclinical findings also translate into clinical decolonization, where intranasal PVP-I significantly improved the efficacy of chlorhexidine wash and was as effective as mupirocin in reducing surgical site infection in orthopedic surgery. Overall, these qualities of PVP-I make it a useful alternative decolonizing agent for the prevention of S. aureus infections, but additional experimental and clinical data are required to further evaluate the use of PVP-I in this setting.

Prophylaxis measures for postinjection endophthalmitis

Intravitreal injections have become the most commonly performed ophthalmic procedure, transforming modern retina practice. Postinjection endophthalmitis, while rare, remains the most feared potential complication. Prophylaxis measures including topical antisepsis, hand hygiene, gloves, masks, and drapes have all been proposed to help prevent postinjection endophthalmitis; however, there remains significant variation in protocol, given the lack of agreement among retina specialists on which steps are crucial to prevent endophthalmitis. With millions of injections performed annually, collating data have helped us better understand risk factors for endophthalmitis after intravitreal injection. We summarize the consensus guidelines for intravitreal injection technique and comprehensively review the literature on prevention of postinjection endophthalmitis.

Intraoperative povidone-iodine irrigation for infection prevention

Although prevention of infection following arthroplasty requires a multifaceted approach, the use of intraoperative irrigation is an important component of any protocol. Recent clinical practice guidelines from the Centers for Disease Control, World Health Organization, and International Consensus Meeting on Musculoskeletal Infection advocate the use of a dilute povidone-iodine solution prior to wound closure. Our experience suggests that this practice is safe, inexpensive, and easily implemented. The present article describes our institutional irrigation protocol and reviews the current literature regarding povidone-iodine solutions.

In Vitro Evaluation of Povidone-Iodine and Chlorhexidine against Outbreak and Nonoutbreak Strains of Mycobacterium abscessus Using Standard Quantitative Suspension and Carrier Testing

Povidone-iodine (PI) and chlorhexidine (CHX) are widely used antiseptics active against conventional Staphylococcus aureus, Enterobacteriaceae, Candida species, and viruses, but their efficacy against Mycobacterium abscessus remains unproven. We determined the in vitro potency of alcoholic PI and CHX against M. abscessus subsp. abscessus (ATCC 19977), M. abscessus subsp. bolletii (BCRC 16915), and our outbreak strain of M. abscessus subsp. massiliense (TPE 101) in reference to Staphylococcus aureus (ATCC 29213) by standard quantitative suspension and carrier methods (EN 14563). By suspension, all mycobacterial strains compared to S. aureus were significantly more resistant to CHX, but not PI. By carrier, the mean logarithmic reductions (LR) achieved by PI under clean (dirty) conditions were 6.575 (2.482), 5.540 (2.298), 4.595 (1.967), and 1.173 (0.889), while those achieved by CHX under clean (dirty) conditions were 3.164 (5.445), 5.307 (2.564), 3.844 (2.232), and 0.863 (0.389) for S. aureus, M. abscessus subsp. bolletii, M. abscessus subsp. abscessus, and M. abscessus subsp. massiliense, respectively. M. abscessus subsp. massiliense (outbreak strain) was significantly more resistant than the other tested strains to PI and CHX. By both methods, the mean LR achieved by PI was higher than for CHX for all mycobacterial strains, but under dirty conditions, neither antiseptic was effectively mycobactericidal (LR < 5). These preliminary findings caution against the universal replacement of PI with CHX as the first-line skin antiseptic, since all M. abscessus isolates were resistant to CHX. More studies are needed to establish the best practice for skin antisepsis if mycobacterial infections are also to be prevented.

Intraoperative Disinfection by Pulse Irrigation with Povidone-Iodine Solution in Spine Surgery

Background

Deep wound infection in spine surgery is a debilitating complication for patients and increases costs. The objective of this prospective study was to evaluate the efficacy of wound pulse irrigation with a dilute povidone-iodine solution in the prevention of surgical site infection.

Methods

50 patients undergoing spinal surgery were randomly divided into two groups (A and B) of 25 patients each. In group A, wounds were irrigated with dilute (3%) povidone-iodine solution through a low-pressure pulsatile device. In group B, wounds were irrigated with saline solution through a bulb syringe. In both groups, specimens for bacterial culture were harvested from surgical site before and after irrigation.

Results

In group A, no surgical site infection occurred; in group B, deep wound infection was observed in 3 patients. In both groups, before irrigation some cultures have been found positive for bacterial contamination.

Conclusion

Our study seems to support the idea that low-pressure pulsating lavage of surgical wounds with povidone-iodine diluted to a nontoxic concentration of 3% is an effective therapeutic adjunct measure to prevent surgical site infection in spine surgery. However, the number of the enrolled patients is small and a significant statistical analysis is not practicable. This trial is registered with NCT03249363.

The Two-Component System ChtRS Contributes to Chlorhexidine Tolerance in Enterococcus faecium

Enterococcus faecium is one of the primary causes of nosocomial infections. Disinfectants are commonly used to prevent infections with multidrug-resistant E. faecium in hospitals. Worryingly, E. faecium strains that exhibit tolerance to disinfectants have already been described. We aimed to identify and characterize E. faecium genes that contribute to tolerance to the disinfectant chlorhexidine (CHX). We used a transposon mutant library, constructed in a multidrug-resistant E. faecium bloodstream isolate, to perform a genome-wide screen to identify genetic determinants involved in tolerance to CHX. We identified a putative two-component system (2CS), composed of a putative sensor histidine kinase (ChtS) and a cognate DNA-binding response regulator (ChtR), which contributed to CHX tolerance in E. faecium Targeted chtR and chtS deletion mutants exhibited compromised growth in the presence of CHX. Growth of the chtR and chtS mutants was also affected in the presence of the antibiotic bacitracin. The CHX- and bacitracin-tolerant phenotype of E. faecium E1162 was linked to a unique, nonsynonymous single nucleotide polymorphism in chtR Transmission electron microscopy showed that upon challenge with CHX, the ΔchtR and ΔchtS mutants failed to divide properly and formed long chains. Normal growth and cell morphology were restored when the mutations were complemented in trans Morphological abnormalities were also observed upon exposure of the ΔchtR and ΔchtS mutants to bacitracin. The tolerance to both chlorhexidine and bacitracin provided by ChtRS in E. faecium highlights the overlap between responses to disinfectants and antibiotics and the potential for the development of cross-tolerance for these classes of antimicrobials.

Decolonization in Prevention of Health Care-Associated Infections

Colonization with health care-associated pathogens such as Staphylococcus aureus, enterococci, Gram-negative organisms, and Clostridium difficile is associated with increased risk of infection. Decolonization is an evidence-based intervention that can be used to prevent health care-associated infections (HAIs). This review evaluates agents used for nasal topical decolonization, topical (e.g., skin) decolonization, oral decolonization, and selective digestive or oropharyngeal decontamination. Although the majority of studies performed to date have focused on S. aureus decolonization, there is increasing interest in how to apply decolonization strategies to reduce infections due to Gram-negative organisms, especially those that are multidrug resistant. Nasal topical decolonization agents reviewed include mupirocin, bacitracin, retapamulin, povidone-iodine, alcohol-based nasal antiseptic, tea tree oil, photodynamic therapy, omiganan pentahydrochloride, and lysostaphin. Mupirocin is still the gold standard agent for S. aureus nasal decolonization, but there is concern about mupirocin resistance, and alternative agents are needed. Of the other nasal decolonization agents, large clinical trials are still needed to evaluate the effectiveness of retapamulin, povidone-iodine, alcohol-based nasal antiseptic, tea tree oil, omiganan pentahydrochloride, and lysostaphin. Given inferior outcomes and increased risk of allergic dermatitis, the use of bacitracin-containing compounds cannot be recommended as a decolonization strategy. Topical decolonization agents reviewed included chlorhexidine gluconate (CHG), hexachlorophane, povidone-iodine, triclosan, and sodium hypochlorite. Of these, CHG is the skin decolonization agent that has the strongest evidence base, and sodium hypochlorite can also be recommended. CHG is associated with prevention of infections due to Gram-positive and Gram-negative organisms as well as Candida. Conversely, triclosan use is discouraged, and topical decolonization with hexachlorophane and povidone-iodine cannot be recommended at this time. There is also evidence to support use of selective digestive decontamination and selective oropharyngeal decontamination, but additional studies are needed to assess resistance to these agents, especially selection for resistance among Gram-negative organisms. The strongest evidence for decolonization is for use among surgical patients as a strategy to prevent surgical site infections.

Bilateral Portal Percutaneous Endoscopic Debridement and Lavage for Lumbar Pyogenic Spondylitis

Common management approaches for spinal infections include conservative administration of antibiotics and aggressive surgical debridement. Minimally invasive endoscopic treatment has been reported and is gaining widespread attention because of its simplicity and effectiveness. This study retrospectively evaluated the clinical outcomes of bilateral portal percutaneous endoscopic debridement and lavage with dilute povidone-iodine solution in the treatment of patients with lumbar pyogenic spondylitis. From January 2007 to December 2011, a total of 22 patients diagnosed with single-level lumbar pyogenic spondylitis underwent bilateral portal percutaneous endoscopic debridement and lavage with dilute povidone-iodine solution at the authors' institution. Clinical outcomes were assessed by careful physical examination, visual analog scale pain score, modified MacNab criteria functional score, regular serologic testing, and imaging studies to determine whether percutaneous endoscopic debridement and lavage treatment was successful or if surgical intervention was required. Causative bacteria were identified in 19 (86.4%) of 22 biopsy specimens. Eighteen patients had satisfactory relief of back pain and uneventful recovery after this treatment. The success rate was 81.8% (18 of 22). Both visual analog scale and modified MacNab criteria scores improved significantly in successfully treated patients. No major surgical complications were noted, except for 3 patients who had residual or subsequent paresthesia in the affected lumbar segment. Percutaneous endoscopic debridement and lavage is a minimally invasive procedure that can yield a higher bacterial diagnosis, relieve back pain, and help to eradicate lumbar pyogenic spondylitis. It is an effective alternative treatment for patients with spinal infection before extensive open surgery.

Limitations of the Efficacy of Surface Disinfection in the Healthcare Setting

We examined the efficacy of 2 commercially available wipes to effectively remove, kill, and prevent the transfer of both methicillin-resistant and methicillin-susceptible Staphylococcus aureus from contaminated surfaces. Although wipes play a role in decreasing the number of pathogenic bacteria from contaminated surfaces, they can potentially transfer bacteria to other surfaces if they are reused.

Antagonistic interactions of "Ya-Sa-Marn-Phlae" ethanol extract in combination with topical antiseptics against clinical isolates of Staphylococcus aureus

This investigation was aimed at assessing a possible interaction of a traditional Thai herbal recipe, "Ya-Sa-Marn-Phlae (YSMP)," used for wound treatments with topical antiseptics, povidone-iodine (PI) solution and hydrogen peroxide (H2O2), and effects of THR-SK010 alone and the combinations on Staphylococcus aureus. Antibacterial activities of ethanol extracts from the herbal recipe were determined against both methicillin resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). YSMP exhibited remarkable antistaphylococcal activity with MIC values of 3.9-7.8 μg/mL. This recipe possessed bacteriostatic activity and did not reduce the tolerance of both MRSA and MSSA isolates to the high ionic strength. Interaction between THR-SK010 and the antiseptics was carried out by checkerboard testing and time-kill assay. Both indifferent and slightly antagonistic effects were observed with THR-SK010/PI and THR-SK010/H2O2 combinations against the tested isolates. In addition to commercially available antiseptics, THR-SK010 offered additional therapeutic options for the decolonization of MRSA and MSSA. Topical application of plant extracts with antioxidant activity, such as THR-SK010, should not be used immediately with PI or H2O2 and further investigation on this interaction is needed.

Minimally invasive endoscopic treatment for lumbar infectious spondylitis: a retrospective study in a tertiary referral center

Background

Spinal infections remain a challenge for clinicians because of their variable presentation and complicated course. Common management approaches include conservative administration of antibiotics or aggressive surgical debridement. The purpose of this study was to evaluate the efficacy of percutaneous endoscopic debridement with dilute betadine solution irrigation (PEDI) for treating patients with lumbar infectious spondylitis.

Methods

From January 2005 to July 2010, a total of 32 patients undergoing PEDI were retrospectively enrolled in this study. The surgical indications of the enrolled patients included single-level infectious spondylodiscitis, postoperative infectious spondylodiscitis, advanced infection with epidural abscess, psoas muscle abscess, pre-vertebral or para-vertebral abscess, multilevel infectious spondylitis, and recurrent infection after anterior debridement and fusion. Clinical outcomes were assessed by careful physical examination, Macnab criteria, regular serologic testing, and imaging studies to determine whether continued antibiotics treatment or surgical intervention was required.

Results

Causative bacteria were identified in 28 (87.5%) of 32 biopsy specimens. Appropriate parenteral antibiotics for the predominant pathogen isolated from infected tissue biopsy cultures were prescribed to patients. Twenty-seven (84.4%) patients reported satisfactory relief of their back pain after PEDI. Twenty-six (81.3%) patients recovered uneventfully after PEDI and sequential antibiotic therapy. No surgery-related major complications were found, except 3 patients with transient paresthesia in the affected lumbar segment.

Conclusions

PEDI was successful in obtaining a bacteriologic diagnosis, relieving the patient’s symptoms, and assisting in the eradication of lumbar infectious spondylitis. This procedure could be an effective alternative for patients who have a poor response to conservative treatment before a major open surgery.

Extended indications of percutaneous endoscopic lavage and drainage for the treatment of lumbar infectious spondylitis

PURPOSE

The treatment of spinal infection remains a challenge for spinal surgeons because of the variable presentations and complicated course. The diagnostic and therapeutic value of percutaneous endoscopic lavage and drainage (PELD) has been proved in some recent studies. The purpose of this study is to evaluate the efficacy of PELD in patients with advanced infectious spondylitis which may traditionally require open surgery.

METHODS

We retrospectively reviewed the medical records of 21 patients who underwent PELD to treat their advanced lumbar infectious spondylitis. Patients with severe infection resulting in significant neurological deficit and mechanical instability were excluded from the PELD procedure, which was only used on selected patients with less severe disease. The 21 patients were categorized into three groups based on their past history, clinical presentation, and imaging studies: those with paraspinal abscesses, postoperative recurrent infection, and multilevel infection. Clinical outcomes were assessed by careful physical examination, Odom's criteria, regular serologic testing, and imaging studies to determine whether continued conservative treatment or surgical intervention was necessary.

RESULTS

Causative bacteria were identified in 19 (90.5%) of 21 biopsy specimens. Appropriate parenteral antibiotics for the predominant pathogen isolated from the infected tissue biopsy cultures were prescribed for the patients. All patients reported satisfactory recovery and relief of back pain, except three with multilevel infections who underwent anterior debridement and fusion within 2 weeks after treatment with PELD. The overall infection control rate was 86%. One patient with epidural abscess and spondylolytic spondylolisthesis of the L5-S1 received instrumented fusion surgery due to mechanical instability 5 months later. No surgery-related major complications were found, except 2 patients who had transient paraesthesia in the affected lumbar segment.

CONCLUSIONS

PELD was successful in obtaining a bacteriologic diagnosis, relieving the patient's symptoms, and assisting in eradication of lumbar infectious spondylitis. The indications of this minimally invasive procedure could be extended to treat patients suffering from spinal infections with paraspinal abscesses and postoperative recurrent infection. Patients with multilevel infection may have trivial benefits from PELD due to poor infection control and mechanical instability of the affected segments.

Current and emergent strategies for disinfection of hospital environments

A significant number of hospital-acquired infections occur due to inefficient disinfection of hospital surfaces, instruments and rooms. The emergence and wide spread of multiresistant forms of several microorganisms has led to a situation where few compounds are able to inhibit or kill the infectious agents. Several strategies to disinfect both clinical equipment and the environment are available, often involving the use of antimicrobial chemicals. More recently, investigations into gas plasma, antimicrobial surfaces and vapour systems have gained interest as promising alternatives to conventional disinfectants. This review provides updated information on the current and emergent disinfection strategies for clinical environments.

An in vitro evaluation of disinfection protocols used for needleless connectors of central venous catheters

A repeatable and sensitive method to evaluate the effect of three antiseptics and two disinfection techniques on viable micro-organisms on luer-activated catheter needleless connectors (NCs) was developed. NCs were inoculated with Staphylococcus epidermidis or Klebsiella pneumoniae and disinfected with 3·15% chlorhexidine gluconate + 70% isopropanol (CGI), 70% isopropanol (IPA) or 10% PVP povidone-iodine (PI) antiseptic pads using: (i) scrubbing the NC septum and threaded external surfaces or (ii) wiping only the surface of the septum. Treatments were also evaluated against NCs pretreated with human serum and exposed for 18 h to Staph. epidermidis prior to testing. Viable cells were quantified by plate count. The method for inoculation and recovery of luminal micro-organisms was repeatable (SD, 0·31; n = 28). IPA disinfection provided an approximate 3 log10  CFU reduction; CGI and PI provided 3-4 log10 reductions. PI and CGI were more effective than IPA (P < 0·05), but differences between CGI and PI were not significant for either disinfection method. IPA, but not CGI and PI was also less effective (P < 0·05) against NCs inoculated with Kl. pneumoniae than Staph. epidermidis. Pretreatment with serum and prolonged Staph. epidermidis inoculation removed the advantage seen with CGI and PI; log10 reductions were 1·80, 1·73 and 2·50 for CGI, PI and IPA, respectively. PI or CGI may be more effective than IPA for NC disinfection but effectiveness may be reduced on NCs contaminated with blood or serum.

SIGNIFICANCE AND IMPACT OF THE STUDY

sensitive and repeatable protocol was developed to evaluate antiseptics for disinfecting catheter needleless connectors (NCs). Povidone-iodine (PI) and chlorhexidine gluconate plus isopropanol (CGI) were more effective than isopropanol (IPA) for reducing Staphylococcus epidermidis contamination of NCs. The effectiveness of PI and CGI was reduced on NCs pre-exposed to human serum and prolonged bacterial inoculation. IPA was also less effective against NCs contaminated with Klebsiella pneumoniae.

Eyelid skin disinfecting and conjunctival bacteria in cataract surgery

PURPOSE

To evaluate the effect on conjunctival micro-organisms of chlorhexidine alcohol 0.5% eyelid wash in cataract patients.

METHODS

In this single-centre experimental study, 120 patients scheduled to undergo cataract operation were cultured in the conjunctiva before the operation and after the insertion of the intraocular lens. Bacterial samples for aerobic and anaerobic cultures were taken with a polyvinyl alcohol pad and transported in peptone water to the microbiological laboratory where they were analysed in a blinded fashion. Half of the patients received a standardized eyelid scrub with chlorhexidine alcohol 0.5%, while the rest did not. The conjunctiva of all patients was rinsed preoperatively with chlorhexidine solution 0.05%.

RESULTS

In all the between-group comparisons, the treated eyelid group had slightly lower bacterial counts than the control group on the postoperative samples, but differences were far from statistically significant. Within-group comparisons revealed statistically significant reduction in colonies and species between the preoperative and postoperative sampling.

CONCLUSION

In this experimental culture study, no evidence was found to suggest that preoperative eyelid chlorhexidine alcohol wash is effective in further reducing bacterial counts in the conjunctiva when the conjunctiva itself is rinsed preoperatively with chlorhexidine solution. The present results, however, do not contradict that the wash may be of some marginal help in reducing bacterial contamination of the operation field. Consequently, this part of the prophylactic protocol is still in practice in our institution.

Limb wounding and antisepsis: iodine and chlorhexidine in the early management of extremity injury

Extremity injury and contamination as consequence are features of high-energy wounding. A leading cause of disability and the commonest cause of late complications, prevention of wound infection determines the ultimate outcome in these populations. Multiple variables influence the development of infection, one of which is the dressing used on the wound. Antiseptic-soaked gauze dressings feature in the early management of limb trauma despite a lack of evidence to support this. Iodine and chlorhexidine are ubiquitous in other aspects of health care however, and a plethora of studies detail their role in skin antisepsis, the recommendations from which are often anecdotally applied to acute wounding. To contextualize the role for antiseptic dressing use in acute, significant limb injury this review explores the evidence for the use of chlorhexidine and iodine in skin antisepsis. The paucity of experimental data available for antiseptic use in early wound management and the need for further research to address this evidence void is highlighted.

Visibility of surgical site marking: a prospective randomized trial of two skin preparation solutions

BACKGROUND

An important component of the surgical time-out is to confirm surgical site skin markings to prevent wrong-site surgery. Different skin preparation solutions may have variable effects on the visibility of site markings after application. We performed a prospective randomized clinical trial to quantitatively and qualitatively evaluate the visibility of surgical site markings after the use of two commonly available skin preparation solutions.

METHODS

We enrolled twenty patients undergoing primary total hip arthroplasty at our institution. Preoperatively, a black permanent marker was used to mark the skin of each patient with a random combination of three letters, underlined by a single black line, and with the surgeon's initials. Patients were randomly selected to receive a chlorhexidine-based or an iodine-based skin preparation according to manufacturer guidelines. The skin markings were photographed digitally, before and after the application of solution. The photographs made after the application of solution were assessed quantitatively, by calculating the contrast (marker to skin) before and after the application of the solutions, and qualitatively by ten orthopaedic surgeons to identify the random initials and to recognize skin markings.

RESULTS

The mean change in contrast level after application of the chlorhexidine-based solution was significantly greater than that after application of the iodine-based solution (mean and standard deviation, 59.8 ± 15.7 U versus 14.9 ± 11.4 U, respectively; p < 0.0001). Surgeons were an average of twenty-two times less likely (95% confidence interval, eight to sixty-eight) to judge markings as acceptable for site identification after preparation with the chlorhexidine-based solution than after preparation with the iodine-based solution. When examining individual letters, the surgeons correctly identified 296 of 300 letters in the group prepared with the iodine-based solution and 209 of 300 letters in the group prepared with the chlorhexidine-based solution; the difference was significant (p < 0.0001).

CONCLUSIONS

The use of the chlorhexidine-based solution for skin preparation resulted in significantly greater erasure of the surgical site marking than did the use of the iodine-based solution.

Dilute betadine lavage before closure for the prevention of acute postoperative deep periprosthetic joint infection

This study evaluated the efficacy of a dilute Betadine (Purdue Pharma, Stamford, Conn) lavage in preventing early deep postoperative infection after total hip (THA) and knee (TKA) arthroplasty. A protocol of dilute Betadine lavage (0.35%) for 3 minutes was introduced to the practice of the senior author in June 2008. A total of 1862 consecutive cases (630 THA and 1232 TKA) performed before this were compared with 688 consecutive cases (274 THA and 414 TKA) after for the occurrence of periprosthetic infections within the first 90 days postoperatively. Eighteen early postoperative infections were identified before the use of dilute Betadine lavage, and 1 since (0.97% and 0.15%, respectively; P = .04). There were no significant demographic differences between the 2 groups. Betadine lavage before wound closure may be an inexpensive, effective means of reducing acute postoperative infection after total joint arthroplasty.

Prevention of post-operative infections in spine surgery by wound irrigation with a solution of povidone-iodine and hydrogen peroxide

INTRODUCTION

Starting from January 2009, we systematically irrigated the surgical wounds of patients undergoing spine surgery with a solution of povidone-iodine (PVP-I) and hydrogen peroxide (H(2)O(2)).

METHOD

We prospectively recorded the clinical data of patients who underwent spine surgery during 2009 and we compared the results with retrospectively reviewed clinical records of patients operated during 2008. Patients were analyzed for preoperative risk factors, type of surgical procedure, onset of the infection, clinical presentation, treatment, and outcome. We performed 460 spine surgeries during 2008 and 490 during 2009.

RESULTS

We recorded seven post-operative infections in 2008 compared to none in 2009.

CONCLUSION

We consider the solution of PVP-I plus H(2)O(2) effective in further reducing the rate of post-operative infection in spine surgery.

Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic

Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

Topical antimicrobial therapy of chronic wounds healing by secondary intention using iodine products

All open wounds healing by secondary intention are contaminated by bacteria and in chronic wounds this can progress through colonisation to invasive infection. Iodine products reduce bacterial load and are active against most species of micro-organisms, and certainly those encountered in chronic wound care. This review evaluates the use of iodine products in chronic wound care including povidone-iodine solutions and cadexomer iodine. Antiseptics containing iodine are relatively cheap, resistance is unknown and concerns about systemic toxicity are probably overstated. More widespread use of these agents as topical anti-microbials in chronic wound care should be considered to reduce the need for systemic antibiotics when colonisation has progressed to invasive infection with systemic signs.

Community-acquired methicillin-resistant Staphylococcus aureus

Published data confirm that community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are increasing in incidence in both urban and rural settings. The statistical risk is higher for athletes, military personnel, prison inmates, intravenous drug abusers, the homeless, children in daycare, and certain Native American groups, but the infections are by no means restricted to these populations. Roughly 85% of the infections involve the skin and subcutaneous tissue, with the most common presentations being an abscess or folliculitis. The typical associated gene cassette is quite small and codes only for methicillin resistance. Abscesses generally respond to drainage.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should recognize groups at high risk for community-acquired MSRA infections and manage these infections appropriately.

The Impact of Povidone-Iodine Pocket Irrigation Use on Pacemaker and Defibrillator Infections

BACKGROUND

Infection is a devastating complication of permanent pacemakers (PMs) implantable cardioverter defibrillators (ICDs). Many implanting physicians commonly use povidone-iodine solution to irrigate the device pocket before implanting the device. We sought to assess if such a measure would alter the rate of infection.

METHODS

A total of 2,564 consecutive patients who received implantable PM or ICD devices between 1994 and 2002 were studied. Povidone-iodine was used for pocket irrigation in 53% and saline in 47%. A total of 18 (0.7%) patients developed pocket infections with 0.7% (10/1,359) in povidone-iodine (group I) and 0.6% (8/1,205) in saline (group II) pocket irrigation (p = ns). Groups I and II were studied for various clinical and demographic variables described in the results section.

RESULTS

There was no statistical difference in the baseline demographic and clinical characteristics between groups I and II, respectively. ICDs were most frequently infected than PMs (56% vs 44%). Most (83%) of the devices were dual chamber. Reopening of the pocket for either lead or generator replacement had a higher incidence of infection than new implants (61% vs 39%). There was no difference in the use of preimplantation antibiotic prophylaxis. Late (61%) and deep pocket infections (78%) were more common than early (39%) and superficial infections (22%). Blood cultures were positive in 67% and Staphylococcus aureus was the common most pathogen (50%). The mean duration of antibiotics use after the diagnosis of device infection was 35 +/- 23 days with 72% requiring device explantation. The device was reimplanted on the contralateral side in 56% cases. One patient in each group died due to device infection and related complications. No significant allergy to iodine was seen in either group.

CONCLUSION

Povidone-iodine irrigation of the subcutaneous pocket did not alter the rates of pocket infection after pacemaker/defibrillator implantation.

Efficacy of dilute betadine solution irrigation in the prevention of postoperative infection of spinal surgery

STUDY DESIGN

Prospective, single-blinded, randomized study.

OBJECTIVES

To evaluate the efficacy of dilute betadine irrigation of spinal surgical wounds in prevention of postoperative wound infection.

SUMMARY AND BACKGROUND

Deep wound infection is a serious complication of spinal surgery that can jeopardize patient outcomes and increase costs. Povidoneiodine is a widely used antiseptic with bactericidal activity against a wide spectrum of pathogens, including methicillin-resistant Staphylococcus aureus. The aim of this study was to evaluate the efficacy of dilute betadine solution in the prevention of wound infection after spinal surgery.

METHODS

Four hundred and fourteen patients undergoing spinal surgery were randomly assigned to two groups. In group 1 (208 patients), surgical wounds were irrigated with dilute betadine solution (3.5% betadine) before wound closure. Betadine irrigation was not used in group 2 (206 patients). Otherwise, perioperative management was the same for both groups.

RESULTS

Mean length of follow-up was 15.5 months in both groups (range, 6-24 months). No wound infection occurred in group 1. One superficial infection (0.5%) and six deep infections (2.9%) occurred in group 2. The differences between the deep infection rate (P = 0.0146) and total infection rate (P = 0.0072) were significant between the two groups.

CONCLUSIONS

Our report is the first prospective, single-blinded, randomized study to evaluate the clinical effectiveness of dilute betadine solution irrigation for prevention of wound infection following spinal surgery. We recommended this simple and inexpensive measure following spinal surgery, particularly in patients with accidental wound contamination, risk factors for wound infection, or undergoing surgery in the absence of routine ultraviolet light, laminar flow, and isolation suits.

The effect of Perasafe® and sodium dichloroisocyanurate (NaDCC) against spores of Clostridium difficile and Bacillus atrophaeus on stainless steel and polyvinyl chloride surfaces

Clostridium difficile is an important cause of nosocomial diarrhoea. The aim of this study was to evaluate the potential for Perasafe, a recently introduced biocide, to contribute to control of C. difficile spores in the patient environment, in comparison with the chlorine-releasing agent sodium dichloroisocyanurate (NaDCC). These agents were evaluated against a water control, in a surface test on stainless steel and polyvinyl chloride (PVC) floor covering, materials commonly found in the hospital environment. The organisms studied were a toxigenic clinical isolate of C. difficile, and Bacillus atrophaeus (formerly B. subtilis var niger). The data indicate that in our in vitro system, Perasafe was significantly more active than NaDCC (1000 ppm available chlorine) against C. difficile spores dried on stainless steel surfaces, and against B. atrophaeus on PVC floor covering material, achieving mean log10 reduction factors in viable counts of 6 and 5.5, respectively, at 10 min exposures. Perasafe appeared to be less lethal in 10 min exposures to C. difficile spores fixed on PVC floor covering material. In general, 1000 ppm chlorine generated from NaDCC showed lower log10 reduction factors in viable counts at 10 min, ranging from 0.7 to 1.5, than Perasafe which ranged from 2.7 to 6.0. The potential efficacy of Perasafe in reducing the density of C. difficile spores in the patient environment in hospitals, nursing homes or other long-stay facilities should be evaluated in field studies.

Association between intensity of chlorhexidine use and micro-organisms of reduced susceptibility in a hospital environment

The potential for emergence of resistance to biocides has been a concern in recent years. This study tested whether an association exists between the intensity of chlorhexidine use and chlorhexidine susceptibility of micro-organisms isolated from patients in different clinical areas in an acute-care general hospital. Organisms frequently involved in nosocomial infections in the hospital were chosen for study over a six week period: Staphylococcus aureus (60 isolates), coagulase-negative staphylococci (48), Klebsiella pneumoniae (32), Pseudomonas aeruginosa (60), Acinetobacter baumannii (16) and Candida albicans (35). An index of chlorhexidine exposure for each clinical unit was derived for the year preceding organism collection. Chlorhexidine susceptibility was evaluated using agar incorporation minimum inhibitory concentrations (MICs) and disk diffusion. A statistically significant inverse correlation was shown between intensity of chlorhexidine use and the overall susceptibility of all study organisms taken together. There was no association when individual taxa were considered. These findings must be interpreted with caution considering that greater use of chlorhexidine is likely to occur in difficult clinical disciplines where antibiotic use, invasive procedures and other intensive care-related procedures, cross-infection and immunosuppression are all potential confounding factors. There was an excellent correlation between MICs and disk testing, suggesting that disk diffusion might be useful in studies involving more than one biocide.

Bactericidal activities of disinfectants against vancomycin-resistant enterococci

The bactericidal activities of 35 commercially available disinfectants against vancomycin-resistant enterococci (VRE) and vancomycin-sensitive enterococci (VSE) were investigated under both clean and dirty (albumin added) conditions using a microtitration plate method. No differences in bactericidal time were observed with any of the test disinfectants when comparing activity against VRE or VSE. Isopropyl alcohol (70 v/v%), alcohol-containing preparations such as Welpas, Wellup and Maskin W . ethanol solution, 0.2% of cation surfactant disinfectants such as Osvan solution 'daigo', Germitol 'Maruishi' 10% and Hyamine solution, and 0.5% of amphoteric compound disinfectants such as TEGO-51, Hygieel and Hypal No.3, were the most effective compounds when compared with other disinfectants. These results suggest that the use of a disinfectant with activity against VRE may be one appropriate method for preventing infections caused by this micro-organism.