Bacterial sensitivity to chlorhexidine and povidone-iodine antiseptics over time: a systematic review and meta-analysis of human-derived data

Chlorhexidine and benzalkonium chloride: promising adjuncts in combating multidrug resistant Klebsiella pneumoniae in healthcare settings

BACKGROUND

Hospital-acquired infections caused by multidrug resistant (MDR) Klebsiella pneumoniae pose a significant global health threat. Effective antisepsis and disinfection protocols are mandatory to prevent these infections. This study aimed to isolate Klebsiella pneumoniae, evaluate antimicrobial susceptibility, and assess the efficacy of selected biocides.

METHODS

Fifty clinical MDR Klebsiella pneumoniae isolates were collected from various hospital departments. Antimicrobial susceptibility was determined using the disc diffusion method. Minimum inhibitory concentrations (MICs) of chlorhexidine and benzalkonium chloride were measured via agar dilution. Conventional PCR was employed to detect biocide resistance genes (qacE∆1 and cepA).

RESULTS

Klebsiella pneumoniae was identified in 19.16% of cases. All isolates exhibited multidrug resistance, with multiple antimicrobial resistance indices ranging from 0.24 to 0.92, reaching up to 1. Benzalkonium chloride MICs significantly increased with resistance, reaching up to 64 µg/mL, while chlorhexidine MICs were consistent across isolates. The qacE∆1 and cepA genes were detected in 62% and 72% of isolates, respectively, with a significant association between qacE∆1 and cephalosporin resistance. No significant correlation was found between biocide MICs and clinical specimen types or hospital units.

CONCLUSION

The cepA gene is closely associated with extensive drug resistance in Klebsiella pneumoniae, emphasizing its role in antimicrobial resistance. Optimized biocide formulations, when properly developed and applied, can play a crucial role in combating and preventing infections caused by multidrug-resistant Klebsiella pneumoniae.

Vaginal antiseptic preparation at the time of hysterectomy: a systematic review and meta-analysis

OBJECTIVE

This study aimed to compare the rates of surgical site infection after hysterectomy using vaginal antisepsis with chlorhexidine gluconate vs povidone-iodine.

DATA SOURCES

PubMed, Embase, and ClinicalTrials.gov databases were queried from January 1, 1985 through December 7, 2023.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials and nonrandomized comparisons of interventions of chlorhexidine gluconate and povidone-iodine vaginal antiseptic preparation before hysterectomy were included. The primary outcome was surgical site infection as defined by the Centers for Disease Control and Prevention. Secondary outcomes included postoperative urinary tract infections and vaginal culture specimens. Large single-group studies of vaginal chlorhexidine gluconate reporting adverse events and case reports of desquamation were also included.

METHODS

The methodologic quality of each study was assessed using the original Cochrane RoB (Risk of Bias) and ROBINS-I (Risk of Bias in Non-Randomized Studies - of Interventions) tools. Restricted maximum likelihood meta-analyses of odds ratios were conducted.

RESULTS

A total of 5289 abstracts were screened; 10 met the inclusion criteria, with a total of 9618 participants. The studies included 4 randomized controlled trials (n=306), 3 prospective nonrandomized comparisons of interventions (n=1089), and 3 retrospective nonrandomized comparisons of interventions (n=8223). Povidone-iodine was compared with 4% chlorhexidine gluconate in 4 studies (n=2491), 2% chlorhexidine gluconate in 2 studies (n=236), 0.1% chlorhexidine gluconate in 1 study (n=50), and both 2% and 4% chlorhexidine gluconate in 1 study (n=49). Meta-analysis revealed no statistically significant difference in surgical site infections, although they were somewhat more common with chlorhexidine gluconate (summary odds ratio, 1.22; 95% confidence interval, 0.91-1.63). The relative effect of antiseptic preparations on urinary tract infections was unclear, with an imprecise summary odds ratio (1.18; 95% confidence interval, 0.65-2.12). Positive vaginal cultures were less common with chlorhexidine gluconate preparation (summary odds ratio, 0.10; 95% confidence interval, 0.04-0.27). Two studies reported no adverse events with chlorhexidine gluconate, and 2 found no difference in vaginal irritation when compared with povidone-iodine. Two case reports described vaginal desquamation or hypersensitivity with chlorhexidine gluconate.

CONCLUSION

There is no evidence of a difference in postoperative infection with chlorhexidine gluconate use compared with povidone-iodine, but chlorhexidine gluconate vaginal preparation results in lower rates of positive intraoperative vaginal cultures. Despite inadequate reporting, risk of adverse events appears low.

Chlorhexidine Versus Povidone-Iodine for Intravitreal Injection Antisepsis: A Systematic Review and Meta-Analysis

PURPOSE

While povidone-iodine (PI) is a commonly used antiseptic solution for postinjection endophthalmitis (PIE) prophylaxis, chlorhexidine (CHX) may be better tolerated by patients. This systematic review and meta-analysis aims to comprehensively compare the efficacy and safety of CHX and PI for PIE prophylaxis.

DESIGN

Systematic Review and Meta-Analysis.

METHODS

MEDLINE, Embase, and the Cochrane Library were systematically searched for relevant literature from January 2000 to July 2024. Studies that compared CHX with PI for either PIE prophylaxis, functional outcomes, or safety outcomes were included. A random-effects meta-analysis was performed, using the Mantel-Haenszel method for dichotomous outcomes and inverse variance method for continuous outcomes. The primary outcomes were the comparative PIE incidence after CHX versus PI. Secondary outcomes pertained to best-corrected visual acuity (BCVA), patient intolerance, pain, safety endpoints, and specimens cultured.

RESULTS

A total of seven studies were included. The incidence of presumed PIE (nCHX = 60/185,849, 0.032% vs nPI = 69/269,491, 0.026%), culture-positive PIE (nCHX = 30/185,849 0.016% vs nPI = 24/269,491, 0.009%; odds ratio [OR] = 2.03, 95% confidence interval [CI] = [0.74, 5.58], P = .17) and culture-negative PIE (nCHX = 30/185,849, 0.016% vs nPI = 45/269,491, 0.017%; OR = 0.97, 95% CI = [0.45, 2.06], P = .93) were nonsignificantly different between PI and CHX groups. No significant risk differences were observed for these outcomes. Across three studies reporting on 54 eyes with culture-positive endophthalmitis, the odds of having positive Staphylococcus epidermidis cultures were significantly lower in the CHX group (nCHX = 9/30, 30.0% vs nPI = 18/24, 75.0%; OR = 0.15, 95% CI = [0.04, 0.54], P = .004); however, the odds were nonsignificantly different for Staphylococcus aureus (P = .64), Streptococcus viridans (P = .46), Streptococcus mitis (P = .83), and Enterococcus faecalis (P = .46). In cases of endophthalmitis, the mean BCVA was nonsignificantly different between CHX and PI groups at the last study observation (P = .67). The systematic review revealed minimal patient intolerance to CHX, more favorable reductions in pain with CHX than PI, greater corneal epitheliopathy with PI than CHX, and nonsignificantly different reductions in ocular surface microbial isolates between comparators.

CONCLUSIONS

CHX and PI were associated with nonsignificantly different rates of presumed, culture-positive, and culture-negative PIE. Endophthalmitis cases associated with both antiseptic agents had a comparable prognosis with respect to BCVA. However, CHX exhibited a more favorable safety and pain profile compared to PI and was associated with a lower odds of positive S. epidermidis cultures in endophthalmitis cases.

Effect of chlorhexidine, povidone-iodine, and hydrogen peroxide irrigation on pain and swelling after mandibular third molar surgery: randomized controlled trial

The objective of this study was to compare the effects of irrigation solutions containing chlorhexidine, povidone-iodine, or hydrogen peroxide on pain and swelling following mandibular third molar surgery. This prospective randomized controlled trial employed a single-blind design. Overall, 112 patients were randomized to four groups based on the antiseptic assigned for the intervention: control, chlorhexidine (CHX), povidone-iodine (PI), and hydrogen peroxide (HP). The patients were followed up on days 1, 3, 7, and 15 after surgery, and pain and swelling were assessed. Data were analysed using ANOVA and post hoc multiple comparison tests. The CHX and HP groups demonstrated significantly lower mean pain scores compared to the control group on days 3 (P = 0.021, P = 0.033) and 7 (P = 0.002, P = 0.017). Regarding the difference in swelling from baseline (before surgery) on each follow-up day, the CHX and HP groups showed significantly less swelling compared to the control group on days 1 (P = 0.023, P = 0.012), 3 (P = 0.007, P = 0.001), and 7 (P = 0.002, P = 0.018). Moreover, the CHX and HP groups demonstrated significantly lower mean swelling changes from baseline compared to PI: CHX vs PI on day 7 (P = 0.032), HP vs PI on day 1 (P = 0.037). In conclusion, chlorhexidine and hydrogen peroxide solutions are highly beneficial options for socket irrigation following mandibular third molar surgery. This study showed a more prominent reduction in pain and swelling with chlorhexidine and hydrogen peroxide solutions compared to povidone-iodine solution.

Environmental bacterial load during surgical and ultrasound procedures in a Swedish small animal hospital

BACKGROUND

Environmental bacteria in animal healthcare facilities may constitute a risk for healthcare-associated infections (HAI). Knowledge of the bacterial microflora composition and factors influencing the environmental bacterial load can support tailored interventions to lower the risk for HAI. The aims of this study were to: (1) quantify and identify environmental bacteria in one operating room (OR) and one ultrasound room (UR) in a small animal hospital, (2) compare the bacterial load to threshold values suggested for use in human healthcare facilities, (3) characterise the genetic relationship between selected bacterial species to assess clonal dissemination, and (4) investigate factors associated with bacterial load during surgery. Settle plates were used for passive air sampling and dip slides for surface sampling. Bacteria were identified by Matrix Assisted Laser Desorption-Time Of Flight. Antimicrobial susceptibility was determined by broth microdilution. Single nucleotide polymorphism-analysis was performed to identify genetically related isolates. Linear regression was performed to analyse associations between observed explanatory factors and bacterial load.

RESULTS

The bacterial load on settle plates and dip slides were low both in the OR and the UR, most of the samples were below threshold values suggested for use in human healthcare facilities. All settle plates sampled during surgery were below the threshold values suggested for use in human clean surgical procedures. Staphylococcus spp. and Micrococcus spp. were the dominating species. There was no indication of clonal relationship among the sequenced isolates. Bacteria carrying genes conveying resistance to disinfectants were revealed. Air change and compliance with hygiene routines were sufficient in the OR. No other factors possibly associated with the bacterial load were identified.

CONCLUSIONS

This study presents a generally low bacterial load in the studied OR and UR, indicating a low risk of transmission of infectious agents from the clinical environment. The results show that it is possible to achieve bacterial loads below threshold values suggested for use in human healthcare facilities in ORs in small animal hospitals and thus posing a reduced risk of HAI. Bacteria carrying genes conveying resistance to disinfectants indicates that resistant bacteria can persist in the clinical environment, with increased risk for HAI.

Incisional Wound Irrigation for the Prevention of Surgical Site Infection: A Systematic Review and Network Meta-Analysis

Importance

Surgical site infections (SSIs) are common postoperative complications and associated with significant morbidity, mortality, and costs. Prophylactic intraoperative incisional wound irrigation is used to reduce the risk of SSIs, and there is great variation in the type of irrigation solutions and their use.

Objective

To compare the outcomes of different types of incisional prophylactic intraoperative incisional wound irrigation for the prevention of SSIs in all types of surgery.

Data Sources

PubMed, Embase, CENTRAL, and CINAHL databases were searched up to June 12, 2023.

Study Selection

Included in this study were randomized clinical trials (RCTs) comparing incisional prophylactic intraoperative incisional wound irrigation with no irrigation or comparing irrigation using different types of solutions, with SSI as a reported outcome. Studies investigating intracavity lavage were excluded.

Data Extraction and Synthesis

This systematic review and network meta-analysis is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Two reviewers independently extracted the data and assessed the risk of bias within individual RCTs using the Cochrane Risk of Bias 2 tool and the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation framework. A frequentist network meta-analysis was conducted, and relative risks (RRs) with corresponding 95% CIs were reported.

Main Outcome and Measure

The primary study outcome was SSI.

Results

A total of 1587 articles were identified, of which 41 RCTs were included in the systematic review, with 17 188 patients reporting 1328 SSIs, resulting in an overall incidence of 7.7%. Compared with no irrigation, antiseptic solutions (RR, 0.60; 95% CI, 0.44-0.81; high level of certainty) and antibiotic solutions (RR, 0.46; 95% CI, 0.29-0.73; low level of certainty) were associated with a beneficial reduction in SSIs. Saline irrigation showed no statistically significant difference compared with no irrigation (RR, 0.83; 95% CI, 0.63-1.09; moderate level of certainty).

Conclusions and Relevance

This systematic review and network meta-analysis found high-certainty evidence that prophylactic intraoperative incisional wound irrigation with antiseptic solutions was associated with a reduction in SSIs. It is suggested that the use of antibiotic wound irrigation be avoided due to the inferior certainty of evidence for its outcome and global antimicrobial resistance concerns.

Enhanced Anti-Bacterial Activity of Arachidonic Acid against the Cariogenic Bacterium Streptococcus mutans in Combination with Triclosan and Fluoride

Dental caries is a global health problem that requires better prevention measures. One of the goals is to reduce the prevalence of the cariogenic Gram-positive bacterium Streptococcus mutans. We have recently shown that naturally occurring arachidonic acid (AA) has both anti-bacterial and anti-biofilm activities against this bacterium. An important question is how these activities are affected by other anti-bacterial compounds commonly used in mouthwashes. Here, we studied the combined treatment of AA with chlorhexidine (CHX), cetylpyridinium chloride (CPC), triclosan, and fluoride. Checkerboard microtiter assays were performed to determine the effects on bacterial growth and viability. Biofilms were quantified using the MTT metabolic assay, crystal violet (CV) staining, and live/dead staining with SYTO 9/propidium iodide (PI) visualized by spinning disk confocal microscopy (SDCM). The bacterial morphology and the topography of the biofilms were visualized by high-resolution scanning electron microscopy (HR-SEM). The effect of selected drug combinations on cell viability and membrane potential was investigated by flow cytometry using SYTO 9/PI staining and the potentiometric dye DiOC2(3), respectively. We found that CHX and CPC had an antagonistic effect on AA at certain concentrations, while an additive effect was observed with triclosan and fluoride. This prompted us to investigate the triple treatment of AA, triclosan, and fluoride, which was more effective than either compound alone or the double treatment. We observed an increase in the percentage of PI-positive bacteria, indicating increased bacterial cell death. Only AA caused significant membrane hyperpolarization, which was not significantly enhanced by either triclosan or fluoride. In conclusion, our data suggest that AA can be used together with triclosan and fluoride to improve the efficacy of oral health care.

Topical antimicrobial treatment of mesh for the reduction of surgical site infections after hernia repair: a systematic review and meta-analysis

PURPOSE

Use of mesh is essential in hernia repair. A common complication after hernia repair is surgical site infection (SSI), which poses a risk in spreading to the mesh, possibly causing mesh infection. Topical antimicrobial pretreatment of mesh may potentially reduce SSI risk in hernia repair and has shown promising results in in vitro and in vivo studies. Clinical evidence, however, is more important. This systematic review aims to provide an overview of available clinical evidence for antimicrobial pretreated mesh in hernia repair surgery to reduce SSI.

METHODS

We report in accordance with PRISMA guidelines. CENTRAL, EMBASE, CINAHL and PubMed were searched up to October 2023 for studies that investigated the use of antimicrobial pretreated mesh on SSI incidence in adults undergoing hernia repair. The primary outcome was SSI incidence. We also collected data on pathogen involvement, hernia recurrence, and mesh infection. A meta-analysis on SSI risk and GRADE-assessment was performed of eligible studies.

RESULTS

We identified 11 eligible studies (n = 2660 patients); 5 randomized trials and 6 cohort studies. Investigated interventions included pre-coated mesh, antibiotic carriers, mesh soaked or irrigated with antibiotic or antiseptic solution. Meta-analysis showed no significant reduction in SSI for antibiotic pretreated polypropylene mesh (RR 0.76 [95% CI 0.27; 2.09]; I2 50%).

CONCLUSION

Data on topical mesh pretreatment to reduce SSI risk after hernia repair is limited. Very low certainty evidence from randomized trials in hernia repair surgery shows no significant benefit for antibiotic mesh pretreatment for SSI reduction, but data are imprecise due to optimal information size not being met.

Comparing the in vitro efficacy of chlorhexidine and povidone-iodine in the prevention of post-surgical endophthalmitis

BACKGROUND

Intravitreal injections are a common ophthalmologic procedure. While infections following these injections are rare, they can lead to endophthalmitis, with potentially serious consequences. Various methods have been proposed to prevent endophthalmitis, including the use of antisepsis and antibiotics in patient preparation.

PURPOSE

To evaluate the antiseptic efficacy of aqueous chlorhexidine (CHX) and povidone-iodine (PI) when used alone and in combination with lidocaine gel (LG) in vitro.

METHODS

Two independent experimental trials were conducted. The first trial determined the minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) of CHX and PI against six bacterial strains. The second trial evaluated the bactericidal efficacy of the antiseptic agents (CHX 0.1% and PI 5%) and their combination with LG against the same bacterial strains.

RESULTS

CHX was more effective than PI in reducing the number of colonies forming units (cfus) of the tested bacteria. The order in which the antiseptic and LG were administered affected their effectiveness, with CHX administered before LG resulting in greater reduction of bacterial growth.

CONCLUSIONS

CHX 0.1% is more effective than PI 5% as an antiseptic agent. Application of CHX and PI prior to the use of lidocaine gel results in a more effective reduction of microorganisms.

In Vitro Effect of Eucalyptus Essential Oils and Antiseptics (Chlorhexidine Gluconate and Povidone-Iodine) against Bacterial Isolates from Equine Wounds

Considering the increasing antibiotics resistance, there has been a propensity to replace them with antiseptics when it comes to wound management and treatment. Nevertheless, in recent years, there have been reports regarding resistance to antiseptics by some bacterial strains. There is also concern about the environmental impact of these substances. The aim of this study was to compare the antimicrobial efficacy of antiseptics and eucalyptus essential oils on bacterial strains from horse's wounds. We used twelve Escherichia coli, eight Staphylococcus aureus, two Staphylococcus pseudintermedius, one Staphylococcus vitulinus and one Staphylococcus saprophyticus strains from equine wounds. The effect of Eucalyptus radiata essential oil, Eucalyptus globulus essential oil, povidone-iodine and chlorhexidine gluconate against the isolated strains was evaluated applying the Kirby-Baüer method. Regarding the Escherichia coli strains, E. radiata and the mixture of E. radiata and E. globulus had a better inhibitory effect than antiseptics. E. globulus had a better effect against most Staphylococcus spp. compared to E. radiata. For both Gram-negative and Gram-positive strains tested, chlorhexidine gluconate had a better inhibitory effect than povidone-iodine. The antibacterial efficacy of essential oils highlights their potential to substitute or complement the use of antiseptics and so reduce resistance to antiseptics.

Antibacterial and Disinfecting Effects of Standardised Tea Extracts on More than 100 Clinical Isolates of Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infections are still a major problem in hospitals. The excellent safety profile, accessibility and anti-infective activity of tea extracts make them promising agents for the treatment of infected wounds. To investigate the possibility of sterilising MRSA-infected surfaces, including skin with tea extracts, we determined the MICs for different extracts from green and black tea (Camellia sinensis), including epigallocatechin gallate (EGCG), on a large number of clinical isolates of MRSA, selected to represent a high genetic diversity. The extracts were prepared to achieve the maximal extraction of EGCG from tea and were used as stable lyophilisate with a defined EGCG content. All extracts showed a complete inhibition of cell growth at a concentration of approx. 80 µg/mL of EGCG after a contact time of 24 h. Time-kill plots were recorded for the extract with the highest amount of EGCG. The reduction factor (RF) was 5 after a contact time of 240 min. EGCG and tea extracts showed an RF of 2 in methicillin-sensitive S. aureus. Extracts from green and black tea showed lower MICs than an aqueous solution with the same concentration of pure EGCG. To the best of our knowledge, we are the first to show a reduction of 99.999% of clinically isolated MRSA by green tea extract within 4 h.

Administration of Clinical COVID-19 Mouthwashing Protocol and Potential Modulation of Pediatric Oral Bacterial Prevalence of Selenomonas noxia: A Pilot Study

Dental office protocols to combat the SARS-CoV-2 (COVID-19) pandemic include mouth washing for an extended 60 s, thereby reducing detectable oral virus. However, it is unclear whether this protocol has any effects on the newly identified periodontal pathogen and obesity-related bacterium often found among pediatric patients, Selenomonas noxia. To determine if the mouthwash protocol has any measurable effect on S. noxia amongst pediatric patients, clinical pediatric saliva samples were obtained from pediatric patients during routine visits for clinical care and treatment. Using an approved protocol, two saliva samples were collected on the same visit before and after chlorhexidine mouthwash (Sample A, Sample B). The third sample (Sample C) was taken at the recall appointment-usually between two and eight weeks later. A total of n = 97 pre-mouthwash samples, and an equal number of matching post-mouthwash samples (n = 97) were collected, with a small number of matching recall samples (n = 36) that were subsequently collected and identified. The demographic composition of the study sample was analyzed using Chi square statistics. Sample DNA from the matching pre-, post-, and recall collections (Sample A, Sample B, and Sample C) was isolated and screened using qPCR and validated primers, which revealed that 11.1% (n = 4/36) from Sample A tested positive for S. noxia with 0% (n = 0/36) of Sample B testing positive and 13.9% (n = 5/36) of the recall (Sample C) testing positive. In addition, comparative analysis of the qPCR cycle threshold data revealed relatively lower expression (quantity) of S. noxia DNA among the recall samples, as determined by two-tailed t-tests (p=0.004). These data and results provide new evidence for the oral prevalence of S. noxia among pediatric patients, while also demonstrating that the COVID-19 protocol of mouth washing prior to clinical treatment for periods extending up to 60 s may be sufficient to reduce the levels of detectable S. noxia-at least temporarily. More research will be needed to determine whether these effects may be limited to the short- or may exhibit more lasting effects in the long-term.