Chemical and microbiologic characteristics and toxicity of povidone-iodine solutions

The effects of chlorhexidine, povidone-iodine and vancomycin on growth and biofilms of pathogens that cause prosthetic joint infections: an in-vitro model

BACKGROUND

Chlorhexidine gluconate (CHG) and povidone-iodine (PI) are commonly used to prevent prosthetic joint infection (PJI) during total joint replacement; however, their effective concentrations and impact on biofilms are not well defined.

AIM

To determine: (1) the in-vitro minimum inhibitory concentration of CHG and PI against model PJI-causing organisms and clinical isolates; (2) their impact on biofilm formation; (3) whether there is a synergistic benefit to combining the two solutions; and (4) whether adding the antibiotic vancomycin impacts antiseptic activity.

METHODS

We measured in-vitro growth and biofilm formation of Staphylococcus epidermidis, meticillin-sensitive and meticillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, as well as recent clinical isolates, in the presence of increasing concentrations of CHG and/or PI. Checkerboard assays were used to measure potential synergy of the solutions together and with vancomycin.

FINDINGS

CHG and PI inhibited growth and biofilm formation of all model organisms tested at concentrations of 0.0004% and 0.33% or lower, respectively; highly dilute concentrations paradoxically increased biofilm formation. The solutions did not synergize with one another and acted independently of vancomycin.

CONCLUSION

CHG and PI are effective at lower concentrations than typically used, establishing baselines to support further clinical trials aimed at optimizing wound disinfection. There is no synergistic advantage to using both in combination. Vancomycin is effective at inhibiting the growth of S. epidermidis and S. aureus; however, it stimulates P. aeruginosa biofilm production, suggesting in the rare case of P. aeruginosa PJI, it could exacerbate infection.

Surgical site antiseptic preparations for otolaryngology - Head and neck surgery: A current review

OBJECTIVE

To review current literature and guidelines on antiseptic surgical site preparations for preventing surgical site infections with consideration of contraindications specific to head and neck surgery.

DATA SOURCES

PubMed/MEDLINE, clinicaltrials.gov, accessdata.fda.gov, Manufacturer websites.

REVIEW METHODS

A scoping review on the literature and clinical studies comparing the efficacy of different surgical site preparations. Studies were included if they were a randomized controlled trial (RCT) comparing at least two commonly used and available antiseptic preparations. Additionally, a compilation of warnings and contraindications from manufacturer labels and articles are included. Due to the lack of randomized controlled trials concerning antiseptic preparation use in head and neck surgery specifically, an additional search was executed for articles not limited to randomized controlled trials that compared different antiseptic preparation used in surgeries concerning the head and neck.

RESULTS

Of 56,983 resulting abstracts and 3798 of them being screened, 25 RCTs were included. These RCTs included a variety of surgeries including gastrointestinal, obstetric, gynecologic, orthopedic, and vascular procedures. When searching for abstracts concerning head and neck surgeries, 9 studies were found and included.

CONCLUSIONS

To reduce surgical site infections and avoid application in situations with contraindications, practicing surgeons need to be familiar with the existing literature regarding different surgical preparations and what warnings manufacturers have listed on the products. Optimal surgical site preparation for head and neck surgery is challenging as proximity to oxygen contraindicates newer alcohol-based options that are potentially flammable. We summarize evidence-based surgical site preparation for head and neck surgery.

Povidone-Iodine Induced Allergic Contact Dermatitis in a 10-Year-Old Girl: A Case Report

We present a case of iodine-induced allergic contact dermatitis in a 10-year-old child. The child had a superficial wound on the left knee from an injury and was treated with daily applications of povidone-iodine (PVP-I) ointment for three to four days. The child subsequently developed a worsening skin lesion that increased from an initial 2 cm to 10 cm, spreading over the upper part of the leg, accompanied by pain and scanty discharge. Referred to the dermatology department, the dermatologist diagnosed iodine-induced allergic contact dermatitis based on the clinical presentation and the absence of other oral or topical medications, as well as no history of allergy to any substances or medications. Discontinuation of the suspected PVP-I ointment led to complete healing within 10 days with the use of only an emollient. This case underscores the importance of recognizing iodine allergy as a potential complication when used in wound care, particularly in pediatric patients.

In vivo assessment of antimicrobial activity and toxicity of repeated 1% povidone-iodine applications vs a single 5% povidone-iodine application

PURPOSE

To demonstrate the noninferiority in antimicrobial effectiveness of thrice-repeated applications of 1% povidone-iodine (PI) compared with a single application of 5% PI on the ocular surface in vivo and to evaluate potential toxicity of PI to the corneal epithelium.

SETTING

Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel.

DESIGN

Prospective, randomized, double-blind study.

METHODS

Patients randomly received either a single application of 5% PI or repeated irrigations of 1% PI on the ocular surface preoperatively. Bacterial colony counts were quantitatively analyzed by taking standardized conjunctival swabs before and after irrigation, and differences in bacterial colony counts were compared between the 2 groups. The presence of superficial punctate keratopathy was evaluated in all patients by the National Eye Institute grading system.

RESULTS

The study comprised 102 eyes of 102 patients. Both 1% and 5% PI yielded a marked decrease in bacterial colonies compared with before application ( P < .001). The repeated application of 1% PI showed a significantly lower bacterial count compared with the single application of 5% PI ( P < .05) and resulted in significantly less damage to the corneal epithelium compared with a single 5% PI application ( P < .001).

CONCLUSIONS

Preoperative repeated applications of 1% PI effectively eradicated ocular surface bacteria equal to that of 5% PI with a less deleterious effect on the corneal epithelium. Our findings suggest that 1% PI may be a promising alternative to 5% PI.

Using 2% PVPI topical solution for serial intravitreous injections and ocular surface findings: a case control study

BACKGROUND

The use of povidone-iodine for ocular surface asepsis is widespread for intravitreal injections. They became frequent procedures, leading to serial exposure of patients' eyes to iodinated solutions. In this study, we investigate the changes in the ocular surface in patients submitted to repeated use of povidine for intravitreal injection of anti-VEGF asepsis, analyzing Ocular Surface Disease Index, non-invasive break up time, blinking quality, lipid layer, meniscus height and osmolarity.

METHODS

This case-control study included 34 individuals (68 eyes), 14 males, 20 females aged 48 to 94. Inclusion criteria were individuals who received application of 2% povidone-iodine eyedrops for intravitreal injections treatment with the non-treated contralateral eye used as control. Ocular surface examinations were performed at a single occasion. A pre-intravitreal injection asepsis protocol with povidone-iodine was applied. All statistical analysis was performed using the STATA® 18.0 Software and a p-value = 0.05 was considered as the statistical significance value in all tests.

RESULTS

The median number of IVIs in treated eyes was 12 (range 6-20). The results in treated eyes compared with untreated eyes were respectively : median OSDI 16 (IQR 6-39) and 12.5 (IQR 8-39) (p = 0.380); mean NIBUT 10.30 (SD ± 2.62) and 10.78 (SD ± 2.92) ( s, p = 0.476); median blinking quality 100 (IQR 100) and 100 (IQR 100 ) (%, p = 0.188); median lipid layer 87 (IQR 77-90) and 86 (IQR 74-100) (nm, p = 0.451); median meniscus height 0.22 (IQR 0.19-0,31) and 0.24 (IQR 0.20-0.27) (mm, p = 0.862), median Meibomian gland atrophy 33 (IQR 24-45) and 31.5 (IQR 25-39) (%, p = 0.524); and mean osmolarity 306.6 (SD ± 21.13) and 313.8 (SD ± 29) (mOsm, p = 0.297). There was no statistically significant relationship between the repetitive use of 2% iodinated solution and signs or symptoms compatible with dry eye syndrome in this group of patients.

CONCLUSIONS

The findings suggest that 2% povidone iodine is a safe and efficacious agent for ocular surface antisepsis during intravitreal injections, not leading to substantial ocular surface modifications. This conclusion supports the continued use of povidone iodine in routine ophthalmic procedures without increased risk of inducing dry eye syndrome.

Efficacy of sucrose and povidone-iodine mixtures in peritoneal dialysis catheter exit-site care

BACKGROUND

Exit-site infection (ESI) is a common recurring complication in patients undergoing peritoneal dialysis (PD). Sucrose and povidone-iodine (SPI) mixtures, antimicrobial ointments that promote wound healing, have been used for the treatment of ulcers and burns, but their efficacy in exit-site care is still unclear.

METHODS

This single-center retrospective observational study included patients who underwent PD between May 2010 and June 2022 and presented with episodes of ESI. Patients were divided into SPI and non-SPI groups and followed up from initial ESI onset until PD cessation, death, transfer to another facility, or June 2023.

RESULTS

Among the 82 patients (mean age 62, [54-72] years), 23 were treated with SPI. The median follow-up duration was 39 months (range, 14-64), with an overall ESI incidence of 0.70 episodes per patient-year. Additionally, 43.1% of second and 25.6% of third ESI were caused by the same pathogen as the first. The log-rank test demonstrated significantly better second and third ESI-free survival in the SPI group than that in the non-SPI group (p < 0.01 and p < 0.01, respectively). In a Cox regression analysis, adjusting for potential confounders, SPI use was a significant predictor of decreased second and third ESI episodes (hazard ratio [HR], 0.22; 95% confidence interval [CI], 0.10-0.52 and HR, 0.22; 95%CI, 0.07-0.73, respectively).

CONCLUSIONS

Our results showed that the use of SPI may be a promising option for preventing the incidence of ESI in patients with PD.

TRIAL REGISTRATION

This study was approved by the Keio University School of Medicine Ethics Committee (approval number 20231078) on August 28, 2023. Retrospectively registered.

Small animal patient preoperative preparation: a review of common antiseptics, comparison studies, and resistance

This review aims to describe commonly used antiseptics in veterinary medicine including their mechanism of action, spectrum of activity, potential adverse effects, and application techniques. Additionally, it provides a review of the veterinary literature comparing antiseptics, a discussion of effectiveness and efficacy studies, and the potential for increased resistance to biocides and antimicrobials. This review concludes that appropriate selection and use is necessary to prevent the occurrence of surgical site infections, adverse effects, and potential for increasing resistance to antimicrobials. Continued research is needed to fill gaps in the current knowledge such as optimal preparation procedures for various surgical sites, standardization of efficacy and effectiveness testing, and the clinical impact of decreased susceptibility to chlorhexidine and other antiseptics.

Wilderness Medical Society Clinical Practice Guidelines on Water Treatment for Wilderness, International Travel, and Austere Situations: 2024 Update

To provide guidance to medical providers, wilderness users, and travelers, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for treating water in situations where the potability of available water is not assured, including wilderness and international travel, areas impacted by disaster, and other areas without adequate sanitation. The guidelines present the available methods for reducing or eliminating microbiological contamination of water for individuals, groups, or households; evaluation of their effectiveness; and practical considerations. The evidence base includes both laboratory and clinical publications. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians.

Comparison of preoperative prophylaxis with povidone-iodine (5%) and moxifloxacin (0.5%) versus povidone-iodine (5%) alone: a prospective study from India

PURPOSE

To compare the effect of povidone-iodine (PI) 5% and moxifloxacin 0.5% solutions versus PI 5% solution alone on the conjunctival bacterial flora.

METHODOLOGY

This is a comparative study in which the study population comprised adult patients scheduled for elective small incision cataract surgery. The eye to be operated (control eye) received topical moxifloxacin 0.5% drops 4 times, 1 day before surgery and 2 applications on the day of surgery. As placebo, the contralateral eye (study eye) received saline 0.90% drops as per the same schedule. Before surgery, on table, PI 5% was instilled in the conjunctival sac in both eyes. Conjunctival swabs were taken before initiation of therapy and 3 min after instillation of PI.

RESULTS

Of the 96 pairs of eyes included in the study, conjunctival cultures before prophylaxis were similar between the two groups (p = 0.31), with 54 samples (56%) of the study group and 49 (51%) of the control group showing growth. With positive cultures reducing to 7 (14%) in the study group and 8 (16%) in the control group, both the prophylaxis methods appeared equally efficacious (p = 0.79). Both the groups showed a significant reduction in positive cultures following prophylaxis (p < 0.0001).

CONCLUSIONS

PI 5% alone as preoperative prophylaxis was as effective as its combination therapy with moxifloxacin 0.5% in the reduction in conjunctival bacterial colonization.

Non-inferiority and Safety of Increased Povidone-Iodine (Betadine) Concentration for Irrigation Following Primary Total Joint Arthroplasty (TJA)

Introduction Diluted Betadine (Purdue Pharma, Stamford, Conn) irrigation following primary total joint arthroplasty (pTJA) may reduce the risk of periprosthetic joint infection (PJI). A recent in vitro study found a minimal inhibitory concentration (MIC) of 0.63% Povidone-iodine (Betadine) for several bacterial isolates. This study reports outcomes of patients undergoing TJA using 0.54% Betadine irrigation compared to a historical cohort using 0.3% Betadine irrigation. Methods A retrospective chart review of patients who underwent pTJA from September 2017 to December 2020. 0.3% Betadine was used in a historical cohort and 0.54% Betadine in the experimental group. Patient demographics, intra-operative data, all-cause revision, and infection data were collected for the three-month post-operative period. Outcome frequencies between groups were compared using Fisher-Exact tests. Results Six hundred sixty-one patients underwent pTJA: 308 total knee arthroplasty (TKA), and 353 total hip arthroplasty (THA). 0.3% Betadine group had seven (3.1%) revisions: five (2.2%) underwent a revision for non-infectious reasons, and two (0.9%) for PJI. 0.54% Betadine group had 11 (2.5%) revisions: nine (2.1%) underwent revision for non-infectious reasons, two (0.4%) for PJI. No significant difference was found for rates of all-cause revision or infection between groups. No adverse intra-operative events occurred with the higher Betadine concentration. Conclusion This study demonstrated no difference in rates of all-cause revision or PJI when using 0.3% Betadine versus 0.54% Betadine for irrigation following pTJA. No adverse intraoperative events occurred with 0.54% Betadine irrigation. Given recent in vitro data supporting increased Betadine MIC, our results showed safety and non-inferiority with respect to three-month post-operative complication rates. Further investigation through a large powered randomized controlled study is needed to determine the optimal Betadine irrigation concentration for PJI prevention is required.

Clinical Efficacy of Different Concentrations of Povidone Iodine in the Management of Peri-Implant Mucositis

Mechanical plaque control is the first line of management of peri-implant diseases. Povidone iodine is one of the broad spectrum and potent antiseptics available at various concentrations. The aim of the study was to assess and compare the efficacy of various concentrations of povidone iodine in the management of peri-implant mucositis. In the present double blinded, parallel designed, randomized clinical trial, a total of 60 patients with peri-implant mucositis (20 participants in each group [Group 1 (povidone iodine 0.1%), Group 2 (povidone iodine 2%) and Group 3 (povidone iodine 010%)] were enrolled. Scaling and root planing was done and then the peri-implant sulcus was irrigated with respective irrigant and repeated once in a week for 4 weeks. Loe and Silness Gingival Index (GI) and Mombelli Modified sulcular bleeding index (BI) were recorded at baseline and after a month and compared. Statistical analysis was done using One-way ANOVA and Tukey's HSD post hoc test. A statistically significant difference (P = 0.000) observed between the three concentrations when compared after 1 month. Also, a statistically significant difference between Group 1 and Group 3 and Group 2 and Group 3 was observed in terms of post GI (P = 0.000) and post BI (P = 0.000) but statistically no significant difference was observed between Group 1 and Group 2 in terms of post GI (P = 0.171) and post BI (P = 0.338). The 2% and 10% povidone iodine showed significant improvement in gingival index and bleeding index and hence it could be an effective adjunct to scaling and root planing in the management of peri-implant mucositis.

In praise of povidone-iodine application in ophthalmology

Polyvinyl pyrrolidone or povidone-iodine (PVP-I) is a water-soluble complex formed by the combination of iodine and a water-soluble polymer, polyvinyl pyrrolidone. This complex exerts bactericidal, fungicidal, and virucidal action by gradually releasing free iodine at the site of application to react with pathogens. In ophthalmology, PVP-I is used as a disinfectant and antiseptic agent for preoperative preparation of the skin and mucous membranes and for treating contaminated wounds. PVP-I has been shown to reduce effectively the risk of endophthalmitis in various ocular procedures, including cataract surgery and intravitreal injections; however, it has also been used in the treatment of conjunctivitis, keratitis, and endophthalmitis, with promising results especially in low-resource situations. PVP-I has been associated with complications such as postoperative eye pain, persistent corneal epithelial defects, ocular inflammation, and an attendant risk of keratitis. In cases of poor PVP-I tolerance, applying PVP-I at lower concentrations or using alternative antiseptics such as chlorhexidine should be considered. We provide an update on the efficacy of PVP-I in the prophylaxis and treatment of conjunctivitis, keratitis, and endophthalmitis and a comprehensive analysis of the current literature regarding the use of PVP-I in the management of these ocular conditions. Also, PVP-I-related adverse effects and toxicities and its alternatives are discussed. The goal is to present a thorough evaluation of the available evidence and to offer practical recommendations for clinicians regarding the therapeutic usage of PVP-I in ophthalmology.

The Use of Iodophor-Impregnated Drapes in Patients With Iodine-Related Allergies: A Case Series and Review of the Literature

Background

The use of iodophor-impregnated adhesive drapes have become almost universally incorporated into standard practice of arthroplasty draping technique. Iodine-related allergies in patients planned for joint replacement present a challenge in terms of the best course of action to minimize complications and optimize outcomes.

Methods

This is a retrospective case series of patients that received an iodophor-impregnated drape as part of draping for a total hip or knee arthroplasty at a single orthopaedic-specific hospital with documented iodine-related allergies. From 2015 to 2023, 9816 total hip arthroplasty and total knee arthroplasty cases were reviewed, and 135 were documented to have an iodine-related allergy for a prevalence of 1.38%. Intraoperative and postoperative records were reviewed to screen for an allergic reaction or wound healing issues that may have been related to an adverse reaction to the use of the iodophor-impregnated drape.

Results

Of the 135 patients, 43 had iodine listed as an allergy, 85 had shellfish, 20 had iodinated contrast media, and 3 had povidone iodine. Sixteen patients had a cluster of iodine-related allergies. There were no intraoperative reports of an allergic reaction to this drape. There were four superficial wound problems, none of which were documented to relate to an allergic dermatitis reaction, and none required further surgery.

Conclusions

Patients reporting iodine-related allergies were present in 1.38% of patients undergoing hip or knee arthroplasty in our series. We encountered no allergic reactions or adverse outcomes that could be attributed to the use of iodiphor impregnated drapes in these patients.

ALTERNATIVE INTRAVITREAL ANTIBIOTICS: A Systematic Review for Consideration in Recalcitrant or Resistant Endophthalmitis

PURPOSE

To organize, categorize, and create a quick reference guide for the use of intravitreal antibiotic alternatives to the standard combination of vancomycin and ceftazidime for the treatment of endophthalmitis.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. The authors searched for all available information regarding intravitreal antibiotics in the last 21 years. Manuscripts were selected according to relevance, level of information, and the available data regarding intravitreal dose, potential adverse effects, bacterial coverage, and relevant pharmacokinetic information.

RESULTS

The authors included 164 of 1810 manuscripts. The antibiotics were classified according to their class into fluoroquinolones, cephalosporins, glycopeptide and lipopeptide, penicillins and beta-lactams, tetracyclines, and miscellaneous. The authors also included information regarding intravitreal adjuvants for the treatment of endophthalmitis and one ocular antiseptic.

CONCLUSION

The treatment of infectious endophthalmitis is a therapeutic challenge. The current review summarizes the properties of possible intravitreal antibiotic alternatives that should be considered in cases of suboptimal response to initial treatment.

Anti-influenza Activity of Povidone-Iodine-Integrated Materials

Personal protective equipment (PPE), including medical masks, should be worn for preventing the transmission of respiratory pathogens via infective droplets and aerosols. In medical masks, the key layer is the filter layer, and the melt-blown nonwoven fabric (NWF) is the most used fabric. However, the NWF filter layer cannot kill or inactivate the pathogens spread via droplets and aerosols. Povidone-iodine (PVP-I) has been used as an antiseptic solution given its potent broad-spectrum activity against pathogens. To develop PPE (e.g., medical masks) with anti-pathogenic activity, we integrated PVP-I into nylon-66 NWF. We then evaluated its antiviral activity against influenza A viruses by examining the viability of Madin-Darby canine kidney (MDCK) cells after inoculation with the virus strains exposed to the PVP-I-integrated nylon-66 NWF. The PVP-I nylon-66 NWF protected the MDCK cells from viral infection in a PVP-I concentration-dependent manner. Subsequently, we found to integrate PVP-I into nylon-66 and polyurethane materials among various materials. These PVP-I materials were also effective against influenza virus infection, and treatment with PVP-I nylon-66 NWF showed the highest cell survival among all the tested materials. PVP-I showed anti-influenza A virus activity when used in conjunction with PPE materials. Moreover, nylon-66 NWF integrated with PVP-I was found to be the best material to ensure anti-influenza activity. Therefore, PVP-I-integrated masks could have the potential to inhibit respiratory virus infection. Our results provide new information for developing multi-functional PPEs with anti-viral activity by integrating them with PVP-I to prevent the potential transmission of respiratory viruses.

Vitrectomy and ILM peeling in rhesus macaque: pitfalls and tips for success

BACKGROUND

The non-human primate (NHP) model is ideal for pre-clinical testing of novel therapies for human retinal diseases due to its similarity to the human visual system. However, intra-ocular delivery of gene therapy or cell transplantation to the retina gets hampered by the sticky vitreous body and poorly permeable inner limiting membrane (ILM) in primates. Although vitrectomy and ILM peeling are commonly performed in patients, many pitfalls exist in carrying out these procedures in the rhesus macaque, which have not been reported previously.

METHODS

We summarised common surgical pitfalls after performing vitrectomy and ILM peeling in four eyes of two rhesus macaques (one male and one female). We provided corresponding hands-on technical tips based on our surgical experience and literature search. Orbital CT scans were compared between adult rhesus macaques and humans. High-resolution surgical videos were recorded to demonstrate each critical surgical step.

RESULTS

Due to size difference, poor post-operative compliance, and high-standard requirements of a controlled experiment, there were eleven common surgical pitfalls during vitrectomy and ILM peeling in rhesus macaque. Falling into these pitfalls may produce discomfort, add fatigue, cause surgical complications, or even lead to the exclusion of the NHP from an experimental group.

CONCLUSION

Recognition and circumvention of these pitfalls during vitrectomy and ILM peeling in NHP are essential. By focusing on these surgical pitfalls, we can better carry out preclinical tests of novel therapies for retinal diseases in the NHP model.

Cell death and barrier disruption by clinically used iodine concentrations

Povidone-iodine (PVP-I) inactivates a broad range of pathogens. Despite its widespread use over decades, the safety of PVP-I remains controversial. Its extended use in the current SARS-CoV-2 virus pandemic urges the need to clarify safety features of PVP-I on a cellular level. Our investigation in epithelial, mesothelial, endothelial, and innate immune cells revealed that the toxicity of PVP-I is caused by diatomic iodine (I2), which is rapidly released from PVP-I to fuel organic halogenation with fast first-order kinetics. Eukaryotic toxicity manifests at below clinically used concentrations with a threshold of 0.1% PVP-I (wt/vol), equalling 1 mM of total available I2 Above this threshold, membrane disruption, loss of mitochondrial membrane potential, and abolition of oxidative phosphorylation induce a rapid form of cell death we propose to term iodoptosis. Furthermore, PVP-I attacks lipid rafts, leading to the failure of tight junctions and thereby compromising the barrier functions of surface-lining cells. Thus, the therapeutic window of PVP-I is considerably narrower than commonly believed. Our findings urge the reappraisal of PVP-I in clinical practice to avert unwarranted toxicity whilst safeguarding its benefits.

Evaluation of the role of povidone‑iodine in the prevention of surgical site infections

Background

The occurrence of surgical site infections (SSIs) is associated with increased risk of mortality, development of other infections, and the need for reintervention, posing a significant health burden. The aim of this review was to examine the current data and guidelines around the use of antiseptic povidone‑iodine (PVP-I) for the prevention of SSIs at each stage of surgical intervention.

Methods

A literature search for selected key words was performed using PubMed. Additional papers were identified based on author expertise.

Results

Scientific evidence demonstrates that PVP-I can be used at every stage of surgical intervention: preoperative, intraoperative, and postoperative. PVP-I is one of the most widely used antiseptics on healthy skin and mucous membranes for preoperative surgical site preparation and is associated with a low SSI rate. For intraoperative irrigation, aqueous PVP-I is the recommended agent and has been demonstrated to decrease SSIs in a range of surgical settings, and for postoperative wound healing, there is a growing body of evidence to support the use of PVP-I.

Conclusions

There is a need for more stringent study designs in clinical trials to enable meaningful comparisons between antiseptic agents, particularly for preoperative skin preparation. The use of a single agent (PVP-I) at each stage of surgical intervention could potentially provide advantages, including economic benefits, over agents that can only be used at discrete stages of the surgical procedure.

Key message

Evidence supports the use of PVP-I at all stages of surgical intervention, from preoperative measures (including skin preparation, preoperative washing, and nasal decolonization) to intraoperative irrigation, through to postoperative wound management. However, there is a need for more stringent study designs in clinical trials to enable meaningful comparisons between antiseptic agents, particularly for preoperative skin preparation.

Donor related corneal graft infection: a review of literature and preventive strategies

PURPOSE

Donor-related infections are a serious threat to patient safety after corneal transplantation. We provide a concise review of literature from the last decade on donor-related graft infections, sources of contamination and means to reduce the contamination of donor tissue and preservation media.

METHODS

We reviewed 50 papers from year 2005 to 2021 related to donor-related graft infections. We included 14 studies related to the risk factors associated with post-keratoplasty infection and preventive methods.

RESULTS

Incidence of post-keratoplasty infections has been reported to be approximately 0.2%-0.77% for endophthalmitis and 6.5%-10.5% for microbial keratitis. We analyzed six important studies regarding the risk factors related to donor contamination. It was observed that younger donor age, increased death to retrieval time, warming cycles and increased eye bank processing time and positive corneo-scleral rim cultures were important risk factors for donor-related infections post keratoplasty. Eye banks have adapted newer protocols over the time period for prevention of donor-related contamination. Recommended preventive strategies were published in about eight important studies over the past decade. In addition to meticulous donor screening, rapid warming cycles, double contact with povidone iodine during retrieval and addition of antifungals like amphotericin B, Voriconazole and cycloheximide have been suggested over the last decade although their use is still in debate with regard to the efficacy, toxicity and cost-effectiveness.

CONCLUSION

The last decade has witnessed a relative rise of fungal infections and multidrug resistant bacterial infections post-keratoplasty. Eye bank prepared corneas for lamellar surgeries are at increased risk for donor contamination due to increased exposure to the higher temperatures during their processing. Addition of antifungals and broad spectrum antibiotics to the hypothermic preservation media needs to be considered in the new era of increasing trends of lamellar keratoplasty.

New In Situ-Generated Polymer-Iodine Complexes with Broad-Spectrum Antimicrobial Activity

Iodine-containing systems show broad antiseptic properties that can be an invaluable tool in controlling infections in humans and animals. Here, we describe the first proof-of-concept studies on biocidal active polyamide- and polyurethane-iodine complexes that are produced in situ directly during the fabrication and/or polymerization process at laboratory and commercially relevant scales. These polymer-iodine materials are active against a broad range of microorganisms, including bacteria and fungi. It is suggested that the ease of manufacture and subsequent commercialization make said systems especially suited for applications as base materials for medical devices to reduce infection risks and control the spread of pathogens. IMPORTANCE Infectious diseases are of mounting medical and public concern. A major contributor to this trend is the proliferation of medical implants, which are inherently vulnerable to microbial contamination and the subsequent onset of hospital-acquired infections. Moreover, implant-associated infections in humans are often difficult to diagnose and treat and are associated with substantial health care costs. Here, we present the development of biocidal active polyamide- and polyurethane-iodine complexes that are generated in situ during fabrication. We show that the excellent antiseptic properties of water-soluble povidone-iodine can be similarly realized in water-insoluble engineering plastics, specifically polyamide- and polyurethane-iodine. These complexes have inherent biocidal activity against major pathogenic bacteria and fungi.

Molecular reaction and dynamic mechanism of iodate reduction to molecular iodine by nitrogen(III) in aqueous solution

This work studies the molecular reaction and dynamic mechanism of iodate reduction by nitrogen(III) in aqueous solution using the ab initio molecular dynamics (AIMD) method based on density functional theory (DFT). Two possible reaction pathways (without and with H⁺) are proposed. The thermodynamic parameters of the proposed reaction pathways are calculated. The theoretical calculation aspects of iodate reduction, including the atomic dipole moment corrected Hirshfeld population (ADCH) atomic charge values, the intrinsic reaction coordinate (IRC) curves, the calculated interaction regional indicator (IRI) isosurfaces with the corresponding sign(λ₂)ρ scatter plots, electrostatic potential (ESP) analysis and molecular reaction dynamics are discussed in-depth. The results show that the reaction pathway with H⁺ is confirmed based on the Gibbs free energy analysis. The transition state proved that the iodate reduction with nitrous acid undergoes four steps according to oxygen-atom deprivation. The IRC curves describe the energy change of the chemical bonds of the reactant conformations in the four steps, with an energy reduction of 71.95, 69.35, 130.15, and 125.87 kJ mol^-1, respectively. The ESP interpenetration diagram and IRI isosurfaces provide detailed information on the nucleophilicity and electrophilicity of the reactant conformations. By decreasing the O atom number in HIO_x (x = 1, 2, 3), the maximum positive charge decreases, and the positive charge coverage area increases, thus resulting in energy reduction and consequently a more stable conformation. Molecular reaction dynamics analytical results indicated that a relatively stable status of the reactants of the four steps was achieved after around 200 fs, and that the HIO₃-HNO₂ reaction released the highest energy.

Prospective evaluation of the prevalence of conjunctival and intraocular bacteria in dogs undergoing phacoemulsification following a standardized aseptic preparation with 0.5% povidone iodine

PURPOSE

To evaluate bacterial contamination of conjunctiva and aqueous humor in dogs undergoing phacoemulsification following asepsis with 0.5% povidone iodine and determine the influence of intravenous antibiotics on outcome of contamination.

METHODS

Client-owned dogs were prospectively enrolled and randomly assigned to a control group, receiving 22 mg/kg intravenous cefazolin at induction prior to sampling, or experimental group receiving no antibiotic prior to sampling, masked to the surgeon. Dogs receiving antimicrobials in the pre-operative period were excluded. Asepsis was performed on all operated eyes using 0.5% iodine with minimum 3 min contact time at induction of anesthesia and repeated before surgery. A conjunctival swab and aqueous humor sample were collected prior to incision and following incision closure, respectively. Samples were submitted for aerobic and anaerobic bacterial culture and susceptibility.

RESULTS

Seventy-one eyes of 42 dogs were included. Median age was 9 years. Thirty-nine and 32/71 eyes received intravenous cefazolin and no antibiotic, respectively. Median procedure time was 40 min per eye. Conjunctival cultures were positive in 6 eyes (8.5%): Serratia marcescens (5 eyes) and Cutibacterium acnes (1 eye). Aqueous humor cultures were positive in 5 eyes (7.0%): S. marcescens (2 eyes), Pseudomonas aeruginosa (2 eyes), Staphylococcus pseudointermedius (1 eye). Prevalence of positive culture did not differ between groups (p = .74), order of eyes for bilateral procedures (p = .74) and diabetic status (p = 1).

CONCLUSIONS

Bacterial contamination of the conjunctiva and aqueous humor was present in 8.5% and 7.0% of dogs undergoing phacoemulsification after asepsis. Lack of IV cefazolin was not significantly associated with positive culture.

Antimicrobial persistence of two alcoholic preoperative skin preparation solutions

BACKGROUND

Normal skin flora and suboptimal skin antisepsis are the primary drivers of healthcare-associated infections (HAIs). Antimicrobial persistence of preoperative skin preparation is necessary to limit microorganisms on the skin and help minimize their entry into an incision or device-insertion site after application.

AIM

To assess the antimicrobial persistence of two preoperative skin preparation solutions.

METHODS

A randomized, single-centre, partially blinded, clinical study was conducted in 103 healthy volunteers to evaluate the persistent antimicrobial properties of BD ChloraPrep™ (2% w/v chlorhexidine gluconate [CHG] + 70% v/v isopropyl alcohol [IPA]) and BD PurPrep™ (8.3% w/w povidone-iodine [PVP-I] + 72.5% w/w IPA) skin preparations out to 7 days and 96 hours, respectively, on abdomen and groin testing sites. An additional 32 healthy volunteers participated in a neutralization procedure to ensure the study recovery solution was non-toxic to microorganisms, and a spore-recovery procedure to demonstrate that microorganisms could be successfully recovered from the PVP-I+IPA film-forming product.

RESULTS

Both CHG+IPA and PVP-I+IPA produced a mean bacterial log₁₀ reduction >2 and >3 on the abdomen and groin, respectively, 10 minutes after application. CHG+IPA maintained antimicrobial persistence out to 7 days post-application, while PVP-I+IPA maintained antimicrobial persistence out to 96 hours post-application, the longest timepoint selected for this product.

CONCLUSION

CHG+IPA and PVP-I+IPA were both found to be effective persistent antiseptic skin preparations. Overall, skin irritation was uncommon, and only 1 adverse event occurred following product application, which was not considered product related but was considered procedure related.

Irrigation techniques used in spine surgery for surgical site infection prophylaxis: a systematic review and meta-analysis

Background

The greater likelihood of morbidity, mortality, length of hospital stays and poorer long-term outcomes as a result of surgical site infections secondary to spinal surgery makes prophylactic measures an imperative focus. Therefore, the aim of this review was to evaluate the available research related to the efficacy of different intraoperative irrigation techniques used in spinal surgery for surgical site infection (SSI) prophylaxis.

Methods

We performed a comprehensive search using Ovid Medline, EMBASE, Web of Science and the Cochrane library pertaining to this topic. Our meta-analysis was conducted according to PRISMA guidelines. The inclusion criteria consist of spine surgeries with intraoperative use of any wound irrigation technique, comparison groups with a different intraoperative irrigation technique or no irrigation, SSI identified with bacterial cultures or clinically in the postoperative period, reported SSI rates. Data extracted from eligible studies included, but was not limited to, SSI rates, irrigation technique and control technique. Exclusion criteria consist of articles with no human subjects, reviews, meta-analyses and case control studies and no details about SSI identification or rates. Pooled risk ratios were calculated. A meta-analysis was performed with a forest plot to determine risk estimates’ heterogeneity with I² index, Q-statistic, and p value under a random-effects model. Funnel plot was used to assess publication bias. All databases were last checked on January, 2022. PROBAST tool was used to assess both risk of bias and applicability concerns.

Results

After reviewing 1494 titles and abstracts, 18 articles met inclusion criteria. They included three prospective randomized-controlled trials, 13 retrospective cohort studies, two prospective cohort studies. There were 54 (1.8%) cases of SSIs in the povidone-iodine irrigation group (N = 2944) compared to 159 (4.6%) in the control group (N = 3408). Using intraoperative povidone-iodine wound irrigation produced an absolute risk reduction of 2.8%. Overall risk ratio was 0.32 (95% CI 0.20–0.53, p < 0.00001). In a global analysis, study heterogeneity and synthesizing mostly retrospective data were primary limitations.

Conclusion

The most evidence exists for povidone-iodine and has Level 2 evidence supporting SSI reduction during spinal surgery. Other antiseptic solutions such as dilute chlorhexidine lack published evidence in this patient population which limits the ability to draw conclusions related to its use in spinal surgery.

Level of Evidence

II – Systematic Review with Meta-Analysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05763-2.

Cell Toxicity Study of Antiseptic Solutions Containing Povidone–Iodine and Hydrogen Peroxide

The increasing incidence of periprosthetic joint infections (PJIs) has led to a growing interest in developing strategies to prevent and treat this severe complication. The surgical site’s application of antiseptic solutions to eliminate contaminating bacteria and eradicate the bacterial biofilm has been increasing over time. Even though it has been proven that combining antimicrobials could enhance their activities and help overcome acquired microbial resistance related to the topical use of antibiotics, the toxicity of integrated solutions is not well described. This study aimed to evaluate the cytotoxicity of solutions containing povidone–iodine (PI) and hydrogen peroxide (H2O2), alone or in combination, after 1.3 and 5 min of exposure. Chondrocytes, tenocytes, and fibroblast-like synoviocytes were used for cytotoxicity analysis. Trypan blue stain (0.4% in PBS) was applied to evaluate the dead cells. All solutions tested showed a progressive increase in toxicity as exposure time increased except for PI at 0.3%, which exhibited the lowest toxicity. The combined solutions reported a reduced cellular killing at 3 and 5 min than H2O2 at equal concentrations, similar results to PI solutions.

Irrigation Solutions and Antibiotic Powders: Should I Use Them in Primary and Revision Total Joint Arthroplasty?

BACKGROUND

The prevention and treatment of periprosthetic joint infection is of utmost importance to orthopedic surgeons. Irrigation solutions have become a popular additive to the prevention and treatment armamentarium.

METHODS

This symposium summarizes the mechanism of action, basic science, and clinical research to date on the use of irrigation solutions. The four most commonly used irrigation solutions, povidone iodine, chlorhexidine, hydrogen peroxide, and acetic acid, are discussed. In addition, the role of antibiotic powers is reviewed.

RESULTS

Each solution has its risks and benefits that must be weighed by the surgeon. There is no clear irrigation solution that is superior. The role of additive antibiotic powder (vancomycin) remains controversial.

CONCLUSION

More rigorous prospective clinical trials are needed to determine the optimal irrigation solution for the prevention and treatment of periprosthetic joint infection.

A novel activated-zinc antiseptic solution effective against MRSA and Pseudomonas aeruginosa: a pig model

OBJECTIVE

The purpose of this study was to investigate the antimicrobial efficacy of a novel activated zinc solution against meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa after one hour, and to evaluate any untoward effect of the solution on local wound tissue at 24 hours after solution exposure in a pig wound model.

METHOD

A pathogen-free, commercially raised, Yorkshire-cross female pig was acquired 12 days prior to the procedure. Within one week prior to the procedure, a small loopful of test bacteria, Pseudomonas aeruginosa (pig-isolate) and MRSA (ATCC-6538), were streaked and cultured on a non-selective agar. Full-thickness wounds (n=24) were created and evenly divided into three groups: control wounds (exposed to bacteria but untreated, n=8); wounds treated with Compound 1 (n=8), and wounds treated with Compound 2 (n=8). All wounds were dressed and monitored for one hour and 24 hours.

RESULTS

After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable total bacteria of 2.8 log colony forming units (CFUs) and 3.5 logCFUs, respectively. After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable MRSA of 2.3 logCFUs and 1.6 logCFUs, respectively (p=0.009). After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable Pseudomonas aeruginosa of 0.3 logCFUs and 0.0 logCFUs, respectively (p=0.000). After 24 hours of exposure to Compound 1 and Compound 2, there was no statistically significant increased necrosis (p=0.12, p=0.31, respectively) or neutrophilic infiltrate (Compound 2, p=0.12) when compared with control wounds.

CONCLUSION

The novel activated-zinc compound used in this study demonstrated a 99.5-99.9% reduction in total bacteria, a 99.9-99.98% reduction in MRSA, and 100% eradication of Pseudomonas aeruginosa one hour after exposure. This novel solution may provide another significant tool to treat and/or prevent wound infections.

Antimicrobial performance of two preoperative skin preparation solutions containing iodine and isopropyl alcohol

BACKGROUND

Healthcare-associated infections (HAIs) are a persistent clinical challenge caused primarily by bacteria on the skin. Proper utilization of optimized antiseptic skin preparation solutions helps reduce the prevalence and impact of HAIs by decreasing patient skin microorganisms preoperatively. The purpose of this study was to evaluate the efficacy of 2 antimicrobial solutions containing iodine and isopropyl alcohol (IPA): Povidone iodine (PVP-I) with IPA (ie, PVP-I+IPA, PurPrep) and Iodine Povacrylex+IPA (DuraPrep).

METHODS

The antimicrobial activity of the test solutions was evaluated in vitro by determinations of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against 1105 diverse microbial isolates and a time-kill assay to evaluate efficacy against 120 strains of Gram-positive and Gram-negative bacteria and yeasts. Peel tests were performed between skin samples treated with test solutions and representative drape/dressing materials to determine effects of test solutions on the biomechanical adhesion properties. Finally, an Institutional Review Board (IRB)-approved, randomized, controlled, single-center, partially blinded in vivo study was performed to assess the immediate and persistent antimicrobial activity of the test solutions on the abdomen and groin.

RESULTS

Both PVP-I+IPA and Iodine Povacrylex+IPA solutions demonstrated broad-spectrum antimicrobial activity with MIC and MBC at less than 1% of the full-strength concentration of each product against a wide variety of microorganisms. In the time-kill tests, both solutions were able to successfully reduce all microbial populations by 99.99% (ie, 4 log₁₀) at the contact times of 30 seconds, 2 minutes and 10 minutes. The 2 solutions showed relatively similar adhesion results when tested with 3 representative operating room materials. Both PVP-I+IPA and Iodine Povacrylex+IPA met the expected Food and Drug Administration (FDA) efficacy requirements at 10 minutes and 6 hours post-treatment for both anatomic sites (ie, groin, and abdomen) in the clinical study, with no safety issues or adverse events.

CONCLUSIONS

Analysis of the in vitro antimicrobial activity, biomechanical adhesive strength, and in vivo efficacy of PVP-I+IPA demonstrated similar results compared to Iodine Povacrylex+IPA. Both products were efficacious at reducing or eliminating a wide range of clinically-relevant microorganisms in lab-based and clinical settings, supporting their use as antiseptic skin preparation solutions to reduce bacteria on the skin that can cause infection.

Bioactivity and antibacterial activity of iodine-containing calcium titanate against implant-associated infection

Developing antimicrobial biomaterials is a major challenge in the fields of orthopaedic and dental implants. In this study, we evaluated the bone-bonding ability and antibacterial activity of a novel biomaterial for preventing implant-associated infections. We have previously reported that NaOH heat treatment improved the bone-bonding ability of titanium, which was later modified to release target ions from the calcium titanate surface. Iodine, an essential nutrient, exhibits broad-spectrum antimicrobial activity; hence, we designed a calcium titanate that releases iodine ions (Ca-I-Ti). The material was prepared from a simple solution using heat treatments as well as inexpensive devices and chemical agents. MC3T3-E1 cells seeded on Ca-I-Ti displayed high degrees of bioactivity and viability, and Ca-I-Ti exhibited antibacterial activity against methicillin-susceptible Staphylococcus aureus. In vivo biomechanical and histological experiments showed that Ca-I-Ti had excellent bone-bonding ability at 8 weeks after implantation. In a subcutaneous infection model in rats, methicillin-susceptible Staphylococcus aureus on the implant was reduced by approximately 95% compared to that on commercially pure titanium, indicating that Ca-I-Ti has antibacterial effects in vivo. In addition, no local or systemic complications were observed, and active infection in the surrounding tissues was histologically inhibited. Thus, iodine-containing calcium titanate is a safe biomaterial with excellent bioactivity and antibacterial properties, indicating its potential in preventing implant-associated infections.

Novel Combined Lidocaine/Povidone Iodine Delivery System for Preintravitreal Injection

Purpose: Intravitreal injection has become a popular treatment for various retina disorders and dramatically increased over the past few years. In traditional preintravitreal injection, the preparation steps are time consuming for practitioners who perform a significant number of injections per day. Besides, lidocaine gel (L-Gel) shows a potential absorption barrier on the antibacterial effect of povidone iodine (PI). Methods: In this study, we describe a L/PI gel system as an alternative approach to address these issues for traditional preinjection drug administration. Lidocaine and PI are loaded in a thermoresponsive gel instilled as a liquid to the lower fornix that transitions to a stable, solid gel depot. Results and Conclusion: The gel demonstrated decrease in conjunctival touch sensitivity and sufficient bacteria killing with a single step, suggesting a significant decrease in the time required and less potential for drug inhibition due to sequential administration.

Molecular iodine is not responsible for cytotoxicity in iodophors

BACKGROUND

Ten percent povidone-iodine (PVP-I) was initially promoted as 'tamed iodine' as the chemical activity of the active biocide, uncomplexed or free molecular iodine (I2), is reduced 30- to 50-fold compared with Lugol's solution. The idea that I2 is responsible for topical iodine staining and irritation remains widely held. However, there are no controlled studies that characterize the cytotoxicity and staining of the hydrophobic I2 species compared with the other hydrophilic iodine species that comprise over 99.9% of the total iodine in topical iodine disinfectants.

AIMS

To compare the staining properties of the I2 species with other topical iodine disinfectants; to evaluate if the concentrations of I2 in diluted PVP-I used to reduce severe acute respiratory syndrome coronavirus-2 in the nasal cavity are potentially cytotoxic; and to determine if high concentrations of I2 can be delivered beyond the stratum corneum into the hypodermis, which could provide a mechanistic rationale for I2 out-gassing.

METHODS

Five liquid compositions that contained complexed and uncomplexed (free) I2 in aqueous and non-aqueous carriers were used to evaluate the interaction of I2 with mammalian cells in culture as well as human and pig skin.

FINDINGS

Concentrations of I2 (7800 ppm) that are 1500 times higher than that found in PVP-I can be applied to skin without irritation and staining. I2 is not cytotoxic at concentrations >100 times higher than that found in PVP-I, and does not contribute materially to staining of skin at concentrations found in Lugol's solution (approximately 170 ppm). I2 can partition into hypodermis tissue, remain there for hours and out-gas from skin. PVP-I and Lugol's solution are highly effective topical disinfectants, but do not facilitate diffusion of I2 through the stratum corneum.

CONCLUSION

The maximum concentration of I2 found in diluted PVP, approximately 25 ppm, is not cytotoxic or irritating. The potential clinical utility of I2 has been limited by incorporating this broad-spectrum biocide into acidic aqueous formulations that contain numerous chemical species that contribute toxicity but not biocidal activity. I2 can be delivered topically into hypodermis tissue without irritation.

Antiseptic Irrigation Solutions Used in Total Joint Arthroplasty: A Critical Analysis Review

»

There are limited data that directly compare the efficacy of antiseptic irrigation solutions used for the prevention and treatment of periprosthetic joint infections in orthopaedic procedures; there is a notable lack of prospective data.

»

For prevention of periprosthetic joint infections, the strongest evidence supports the use of low-pressure povidone-iodine.

»

For the treatment of periprosthetic joint infections, delivering multiple solutions sequentially may be beneficial.

Safety Measures for Maintaining Low Endophthalmitis Rate after Intravitreal Anti-Vascular Endothelial Growth Factor Injection before and during the COVID-19 Pandemic

During the COVID-19 pandemic, intravitreal injections are performed with patients wearing masks. The risk of endophthalmitis after intravitreal injection is reported to increase due to an influx of exhaled air containing oral bacteria from the upper part of the mask onto the ocular surface. We retrospectively investigated the incidence of endophthalmitis when intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections were performed using the same infection control measures before and during the pandemic. Vitreoretinal specialists performed intravitreal injections of anti-VEGF agents in the outpatient room of a university hospital. Infection control measures before and during the pandemic included covering the patient’s eye with adhesive face drape and irrigating the ocular surface with 0.25% povidone-iodine before draping, and immediately before and after injection. Before the COVID-19 pandemic (February 2016 to December 2019), one case of endophthalmitis occurred among 31,173 injections performed (0.0032%; 95% confidence interval (CI), 0.000008–0.017872%). During the COVID-19 pandemic (January 2020 to August 2021), one case of endophthalmitis occurred among 14,725 injections performed (0.0068%; 95% CI, 0.000017–0.037832%). There was no significant difference between the two periods (Fisher’s exact test: p = 0.5387). Even during the COVID-19 pandemic, very low incidence of endophthalmitis after intravitreal injection can be maintained by implementing basic infection prophylactic measures, including face draping and 0.25% povidone-iodine irrigation, established before COVID-19 pandemic.

Low-concentration povidone-iodine for the prevention of intraocular infections in ophthalmic surgery

PURPOSE OF REVIEW

Endophthamitis following intraocular surgery is rare using current antiseptic techniques, such as single application of 5% povidone-iodine to the ocular surface and adjuvant topical or intracameral antibiotics. Challenges remain, however, including increased multidrug-resistant bacterial endophthalmitis, increased fungal endophthalmitis, and the low but nonzero endophthalmitis rate attributable to the typical bacteria that colonize the ocular surface.

RECENT FINDINGS

Povidone-iodine has a wide spectrum of activity, including activity against novel pathogens, such as SARS-CoV-2. Povidone-iodine alternatives, such as hypochlorous acid can have significantly less efficacy in vitro against endophthalmitis isolates. Repetitive application of dilute povidone-iodine has an excellent safety profile and strong evidence base for efficacy.

SUMMARY

Povidone-iodine is widely available, inexpensive, and commonly used by ophthalmologists. The repetitive application of dilute povidone-iodine is a well studied, well tolerated, and efficacious way to transiently sterilize the ocular surface during intraocular surgery. Additional benefits include activity against multidrug-resistant bacteria, fungi, and lack of inducible resistance.

Effect of dental antiseptic agents on the viability of human periodontal ligament cells

•

Cell viability is key for tissue regeneration.

•

Dental antiseptics were cytotoxic in periodontal ligament cells.

•

Real-time impedimetry proved to be a non-invasive method to monitor cell viability.

Objectives

We aimed to study whether or not various dental antiseptic agents affect the viability and proliferation of human periodontal ligament cells (PDLCs).

Materials and methods

Human PDLCs were isolated from a total of 10 surgically extracted impacted third molars and were.

cultured in-vitro. The cells were exposed to commonly used dental antiseptics, including chlorhexidine, cetylpyridinium chloride, triclosan, povidone-iodine and sodium bicarbonate for ultra-short-term (10, 20, 30 sec), short-term (10, 20, 30 min) and long-term (24, 48 h) at various concentrations. Cell morphology was observed with light microscopy. Cell viability was studied with impedimetric real-time xCELLigence and resazurin-based alamarBlue® assays. We used one-way ANOVA with Tukey’s and Bonferroni test (p < 0.05) for statistical analysis.

Results

Both alamarBlue® and xCELLigence analysis results were in agreement that ultra-short-term contact with cetylpyridinium chloride ≥ 0.01 mg/ml, chlorhexidine ≥ 1 mg/ml, triclosan ≥ 1 mg/ml and povidone-iodine ≥ 1 mg/ml as well as long-term exposure to cetylpyridinium chloride ≥ 0.001 mg/ml, chlorhexidine ≥ 0.01 mg/ml, triclosan ≥ 1 mg/ml, povidone-iodine ≥ 1 mg/ml and sodium bicarbonate ≥ 10 mg/ml was able to reduce the viability of human PDLCs significantly. According to the half-maximal inhibitory concentration (IC50) the rank of cytotoxicity was cetylpyridinium chloride > chlorhexidine > triclosan > povidone-iodine > sodium bicarbonate.

Conclusions

Our findings suggest that the tested antiseptic agents were cytotoxic to human PDLCs at lower than practically applied concentrations in dental interventions.

In vivo antimicrobial activity of 0.6% povidone-iodine eye drops in patients undergoing intravitreal injections: a prospective study

To investigate the antimicrobial activity of a preservative-free 0.6% povidone-iodine eye drop as an antiseptic procedure in decreasing the conjunctival bacterial load in eyes scheduled for intravitreal treatment and to compare its efficacy to the untreated fellow eye used as the control group. Prospective cohort analysis in which 208 patients received preservative-free 0.6% povidone-iodine eye drops three times a day for three days before intravitreal injection. Before and after the prophylactic treatment, a conjunctival swab was collected from both the study eye and the untreated contralateral eye, used as control. The swab was inoculated on different culture media and the colony-forming units were counted. Bacteria and fungi were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Treatment with 0.6% povidone-iodine eye drops significantly reduced the conjunctival bacterial load from baseline (p < 0.001 for blood agar and p < 0.001 for chocolate agar) with an eradication rate of 80%. The most commonly isolated pathogen at each time-point and in both groups was coagulase-negative Staphylococci, isolated in 84% of the positive cultures. The study provides evidence about the effectiveness of 0.6% povidone-iodine eye drops treatment in reducing the conjunctival bacterial load in eyes scheduled for intravitreal treatment.

Effectiveness of mouthwash against viruses: 2020 perspective. A systematic review

INTRODUCTION

Antiseptic mouthwash is widely recommended to treat various oral diseases as well as to improve oral health. Most of the dental procedures lead to the generation of aerosols. These aerosols have a high potential to transmit disease. Preprocedural oral rinse with antimicrobial agents in the form of mouthwashes reduces the bacterial and viral load many folds. The purpose of this review was to summarize the effectiveness of mouthwash against viruses affecting human beings.

EVIDENCE ACQUISITION

Search engines like PubMed, Google Scholar, and others were used to search the electronic database. Articles were identified in which the effectiveness of antiseptic mouth rinse against the virus was tested. A comprehensive search strategy was designed to select the articles and then independently screened for eligibility.

EVIDENCE SYNTHESIS

A total of 9624 articles out of the 13 titles met the eligibility criteria. The selected papers were included in the present manuscript according to their relevance to the topic. Authors searched the most used chemicals as mouthwashes but records of three types of mouthwash tested against various types of viruses i.e. chlorhexidine gluconate, Povidone-iodine and essential oil containing mouthwash (Listerine) were found.

CONCLUSIONS

Povidone-iodine mouth rinse is effective in reducing viral load either in-vitro or in-vivo conditions. Chlorhexidine gluconate mouthwash and essential oils have shown its effectiveness in a few studies. Insufficient evidence is available to support the claim that oral antiseptics can reduce the risk of developing viral loads in humans or the rate of progression of diseases caused by viruses.

Efficient inactivation of African swine fever virus by a highly complexed iodine

African swine fever (ASF) is a highly lethal contagious disease of swine caused by African swine fever virus (ASFV). Cleaning and disinfection remain one of the most effective tools to prevent the ASFV spread in pig holdings. This study evaluated the inactivation effect of a highly complexed iodine (HPCI) disinfectant against ASFV. A commercially available povidone-iodine (PVP-I) was used as reference for comparison. The results showed that 5% HPCI and 5% PVP-I did not exhibit cytotoxicity in primary porcine alveolar macrophages, and 10^7.0 and 10^5.0 TCID₅₀/mL ASFV were completely inactivated by 5% and 0.25% HPCI, respectively, in 5 min via either immersion or spray disinfection. However, 5% PVP-I required at least 15 min to completely inactivate 10^7.0 TCID₅₀/mL ASFV, whereas 0.25% PVP-I failed to completely inactivate 10^5.0 TCID₅₀/mL ASFV. This study demonstrated that HPCI could rapidly and efficiently inactivate ASFV, representing an effective disinfectant for ASF control.

What Is the Optimal Irrigation Solution in the Management of Periprosthetic Hip and Knee Joint Infections?

BACKGROUND

Thorough irrigation and debridement using an irrigation solution is a well-established treatment for both acute and chronic periprosthetic joint infections (PJIs). In the absence of concrete data, identifying the optimal irrigation agent and protocol remains challenging.

METHODS

A thorough review of the current literature on the various forms of irrigations and their additives was performed to evaluate the efficacy and limitations of each solution as pertaining to pathogen eradication in the treatment of PJI. As there is an overall paucity of high-quality literature comparing irrigation additives to each other and to any control, no meta-analyses could be performed. The literature was therefore summarized in this review article to give readers concise information on current irrigation options and their known risks and benefits.

RESULTS

Antiseptic solutions include povidone-iodine, chlorhexidine gluconate, acetic acid, hydrogen peroxide, sodium hypochlorite, hypochlorous acid, and preformulated commercially available combination solutions. The current literature suggests that intraoperative use of antiseptic irrigants may play a role in treating PJI, but definitive clinical studies comparing antiseptic to no antiseptic irrigation are lacking. Furthermore, no clinical head-to-head comparisons of different antiseptic irrigants have identified an optimal irrigation solution.

CONCLUSION

Further high-quality studies on the optimal irrigation additive and protocol for the management of PJI are warranted to guide future evidence-based decisions.

Intraocular Povidone Iodine During Pars Plana Vitrectomy for Severe and Atypical Endophthalmitis

BACKGROUND AND OBJECTIVE

To describe the experience and clinical outcomes of povidone iodine (PI) infusion in the setting of pars plana vitrectomy for the treatment of endophthalmitis.

MATERIALS AND METHODS

This was a retrospective case series of 12 patients with clinical and/or culture evidence of endophthalmitis requiring pars plana vitrectomy with 0.025% PI used in vitreous irrigation solution during vitrectomy. The primary endpoint was clinical resolution of the infection. Secondary endpoints included visual recovery, need for repeat surgery, and ocular toxicity RESULTS: There were 11 eyes that showed clinical or culture evidence of resolution of infection postoperatively (91.7%); 10 eyes had improvement in vision postoperatively (83.3%). Overall uncorrected visual acuity improved from 20/5321 (2.43 ± 0.58 logMAR) to 20/375 (1.27 ± 1.05 logMAR) (P = .0003). No clinical evidence of ocular toxicity or unexplained vision loss due to PI was observed.

CONCLUSIONS

PI infusion during pars plana vitrectomy for endophthalmitis appears safe and led to excellent post-surgical results in a traditionally high-risk cohort. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:485-490.].

Cataract Surgery by Intraoperative Surface Irrigation with 0.25% Povidone-Iodine

Postoperative endophthalmitis after cataract surgery is typically caused by the patient's own conjunctival normal bacterial flora. A three-step approach is recommended to prevent endophthalmitis: (1) "border control" to prevent microorganisms from entering the eye by disinfecting the ocular surface is the most important measure; (2) bacteria that have gained access into the anterior chamber are reduced by irrigation; (3) bacteria remaining in the anterior chamber and vitreous at the end of surgery are controlled by antibacterial drugs. We have devised a method, "the Shimada technique", for irrigating the ocular surface with povidone-iodine, a disinfectant with potent microbicidal effect and established effective and safe concentrations for eye tissues. Povidone-iodine exhibits a bactericidal effect for a wide concentration range of 0.005-10%, but 0.1% povidone-iodine has the highest activity and requires the shortest time of only 15 s to achieve microbicidal effect. When used to irrigate the ocular surface every 20-30 s during cataract surgery, 0.25% povidone-iodine is conceivably diluted to around 0.1%. Irrigation with 0.25% povidone-iodine during cataract surgery significantly reduced bacteria contamination rate in the anterior chamber compared with saline (p = 0.0017) without causing corneal endothelial damage.

Does Endogenous Endophthalmitis Need a More Aggressive Treatment?

Topic: To focus on endogenous endophthalmitis management, particularly etiology-based medical and surgical therapy.Methods: Literature search of published studies from July 1990 to February 2019 on endogenous endophthalmitis available on PubMed was made without any language constraints.Results: A total of 78 articles were retrieved from 728 initially analyzed and 62 studies were included. Although the superiority of vitrectomy over tap and inject techniques is controversial, the most recent publications favor an early surgical approach for endogenous endophthalmitis. Vitrectomy is useful in severe cases complicated by marked vitreous opacity, retinal detachment, poor initial visual acuity, and more virulent pathogens. Oral or intravenous antibiotics are also necessary to treat systemic infection. Vitrectomy is superior to blood cultures in diagnosing the etiology of infection.Conclusions: Endogenous endophthalmitis is an important cause of visual acuity impairment. Prompt treatment with appropriate use of pharmacological or surgical therapy is mandatory to preserve visual function.Abbreviations: IOP: intra-ocular pressure; AIDS: acquired immune deficiency syndrome; EVS: endophthalmitis vitrectomy study; CEVE: complete and early vitrectomy for endophthalmitis.

Antibacterial Activity in Iodine-coated Implants Under Conditions of Iodine Loss: Study in a Rat Model Plus In Vitro Analysis

BACKGROUND

We developed iodine-coated titanium implants to suppress microbial activity and prevent periprosthetic joint infection (PJI); their efficacy was demonstrated in animal and in vitro models. The iodine content in iodine-coated implants naturally decreases in vivo. However, to our knowledge, the effect of reduced iodine content on the implant's antimicrobial activity has not been evaluated to date.

QUESTIONS/PURPOSES

(1) How much does the iodine content on the implant surface decrease after 4 and 8 weeks in vivo in a rat model? (2) What effect does the reduced iodine content have on the antimicrobial effect of the implant against multiple bacteria in an in vitro model?

METHODS

This experiment was performed in two parts: an in vivo experiment to determine attenuation of iodine levels over time in rats, and an in vitro experiment in which we sought to assess whether the reduced iodine content observed in the in vivo experiment was still sufficient to deliver antimicrobial activity against common pathogens seen in PJI. For the in vivo experiment, three types of titanium alloy washers were implanted in rats: untreated (Ti), surface-anodized to produce an oxide film (Ti-O), and with an iodine layer on the oxidation film (Ti-I). The attenuation of iodine levels in rats was measured over time using inductively coupled plasma-mass spectrometry. Herein, only the Ti-I washer was used, with five implanted in each rat that were removed after 4 or 8 weeks. For the 4- and 8-week models, two rats and 15 washers were used. For the in vitro study, to determine the antibacterial effect, three types of washers (Ti, Ti-O, and Ti-I) (nine washers in total) were implanted in each rat. Then, the washers were removed and the antibacterial effect of each washer was examined on multiple bacterial species using the spread plate method and fluorescence microscopy. For the spread plate method, six rats were used, and five rats were used for the observation using fluorescence microscopy; further, 4- and 8-week models were made for each method. Thus, a total of 22 rats and 198 washers were used. Live and dead bacteria in the biofilm were stained, and the biofilm coverage percentage for quantitative analysis was determined using fluorescence microscopy in a nonblinded manner. Ti-I was used as the experimental group, and Ti and Ti-O were used as control groups. The total number of rats and washers used throughout this study was 24 and 213, respectively.

RESULTS

Iodine content in rats implanted with Ti-I samples decreased to 72% and 65% after the in vivo period of 4 and 8 weeks, respectively (p = 0.001 and p < 0.001, respectively). In the in vitro experiment, the Ti-I implants demonstrated a stronger antimicrobial activity than Ti and Ti-O implants in the 4- and 8-week models. Both the median number of bacterial colonies and the median biofilm coverage percentage with live bacteria on Ti-I were lower than those on Ti or Ti-O implants for each bacterial species in the 4- and 8-week models. There was no difference in the median biofilm coverage percentage of dead bacteria. In the 8-week model, the antibacterial activity using the spread plate method had median (interquartile range) numbers of bacteria on the Ti, Ti-O, and Ti-I implants of 112 (104 to 165) × 105, 147 (111 to 162) × 105, and 55 (37 to 67) × 105 of methicillin-sensitive Staphylococcus aureus (Ti-I versus Ti, p = 0.026; Ti-I versus Ti-O, p = 0.009); 71 (39 to 111) × 105, 50 (44 to 62) × 105, and 26 (9 to 31)× 105 CFU of methicillin-resistant S. aureus (Ti-I versus Ti, p = 0.026; Ti-I versus Ti-O, p = 0.034); and 77 (74 to 83) × 106, 111 (95 to 117) × 106, and 30 (21 to 45) × 106 CFU of Pseudomonas aeruginosa (Ti-I versus Ti, p = 0.004; Ti-I versus Ti-O, p = 0.009). Despite the decrease in the iodine content of Ti-I after 8 weeks, it demonstrated better antibacterial activity against all tested bacteria than the Ti and Ti-O implants.

CONCLUSION

Iodine-coated implants retained their iodine content and antibacterial activity against methicillin-sensitive S. aureus, methicillin-resistant S. aureus, and P. aeruginosa for 8 weeks in vivo in rats. To evaluate the longer-lasting antibacterial efficacy, further research using larger infected animal PJI models with implants in the joints of both males and females is desirable.

CLINICAL RELEVANCE

Iodine-coated titanium implants displayed an antibacterial activity for 8 weeks in rats in vivo. Although the findings in a rat model do not guarantee efficacy in humans, they represent an important step toward clinical application.

Povidone Iodine Disinfection Associated with Hypothyroidism and Potentially Contributing to Prolonged Kidney Failure

Objectives

To report a case of povidone-iodine (PVP-I, Iso-Betadine®) disinfection of lower leg fasciotomy wounds resulting in iodide absorption and possibly contributing to hypothyroidism and prolonged kidney injury.

Design

Case report. Setting. Pediatric intensive care unit (PICU), university hospital. Patients. A 13-year-old patient presenting with prolonged oligoanuric kidney failure and unexplained primary hypothyroidism three weeks after severe abdominal sepsis with multiple organ dysfunction and major rhabdomyolysis due to bilateral lower leg compartment syndrome, necessitating moderate size fasciotomies, disinfected daily with PVP-I. Interventions. Interruption of PVP-I exposure and initiation of thyroid hormone substitution. Measurements and Main Results. Hypothyroidism was revealed during diagnostic work-up for persistent hypertriglyceridemia. Thyroxine (T4) (4.0 mg/L) and tri-iodothyronine (T3) (64 ng/L) were moderately low, yet thyroid stimulating hormone (TSH) (16.8 mIU/L) was fourfold the maximal normal range value. This pattern, atypical for prolonged critical illness-related hypothyroidism, prompted interruption of PVP-I exposure and initiation of thyroid hormone substitution. Urinary production and creatinine clearance recovered during the following days, and one week later, intermittent renal replacement therapy could be terminated, suggesting that PVP-I toxicity and/or hypothyroidism may have contributed to the persistent renal failure three weeks after resolved septic shock and rhabdomyolysis. Elevated serum and urinary anion gap normalized simultaneously, but this evolution of rather nonspecific indices could be multifactorial.

Conclusion

PVP-I is a commonly used broad-spectrum antimicrobial agent for prevention and treatment of wound infections. Toxic complications due to PVP-I absorption, after disinfection of extended thermal injuries larger than 20% of the body surface, have been described. In critically ill children, however, toxic effects of PVP-I may occur due to repeated disinfection of less extended wounds. Proposed screening strategies include: monitoring of the volumes of PVP-I applied daily; of the thyroid function, the serum, and/or urinary anion gap and the urinary iodide concentrations. These strategies, however, remain to be validated. This case report should be a wake-up call for daily integration of wound management in the clinical evaluation of critically ill patients.

Comparison of Povidone-Iodine and Gentamicin Soak as Scleral Buckle Infection Prophylaxis

Objective

To determine the best method of antimicrobial prophylaxis against implanted material-associated infections in the setting of scleral buckle surgery.

Design

Experimental study.

Participants

Scleral buckle elements were soaked in either gram-positive or polymicrobial broth, while control buckle elements were soaked in PBS only.

Methods

Solid silicone and sponge scleral buckle elements were inoculated with common pathogens of the ocular surface, and then soaked in either 1% or 5% povidone-iodine, 1 mg/mL gentamicin solution, or sterile saline for 1, 5, 10, or 15 minutes. Bacteria were then isolated from the buckle elements and cultured for 24 hours.

Results

In all gram-positive bacterial conditions, gentamicin solution decreased the bacterial load from 451,666.67 colony-forming units (CFU)/mL to 171,611.11 CFU/mL (p=0.0004). The fractional bacterial survival after soaking in gentamicin was higher for the silicone sponge than band (0.357 vs 0.079, p=0.038). Both 1% and 5% povidone-iodine were able to completely eradicate all gram-positive bacteria of both buckle elements. Only 5% povidone-iodine was able to completely sterilize all microbes on the buckle after soaking in a polymicrobial solution consisting of gram-positive, gram-negative bacteria, and fungi.

Conclusion

Povidone-iodine solution was significantly more effective at bacterial eradication compared to gentamicin solution. For all scleral buckle procedures, we recommend soaking the buckle element in 2–3% povidone-iodine solution before placement and rinsing the ocular surface with the same solution after placement.

Effectiveness of 0.66% Povidone-Iodine Eye Drops on Ocular Surface Flora before Cataract Surgery: A Nationwide Microbiological Study

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM^®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM^®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure.