Chlorhexidine: Patient Bathing and Infection Prevention

In Vitro Screening of a 1280 FDA-Approved Drugs Library against Multidrug-Resistant and Extensively Drug-Resistant Bacteria

Alternative strategies against multidrug-resistant (MDR) bacterial infections are suggested to clinicians, such as drug repurposing, which uses rapidly available and marketed drugs. We gathered a collection of MDR bacteria from our hospital and performed a phenotypic high-throughput screening with a 1280 FDA-approved drug library. We used two Gram positive (Enterococcus faecium P5014 and Staphylococcus aureus P1943) and six Gram negative (Acinetobacter baumannii P1887, Klebsiella pneumoniae P9495, Pseudomonas aeruginosa P6540, Burkholderia multivorans P6539, Pandoraea nosoerga P8103, and Escherichia coli DSM105182 as the reference and control strain). The selected MDR strain panel carried resistance genes or displayed phenotypic resistance to last-line therapies such as carbapenems, vancomycin, or colistin. A total of 107 compounds from nine therapeutic classes inhibited >90% of the growth of the selected Gram negative and Gram positive bacteria at a drug concentration set at 10 µmol/L, and 7.5% were anticancer drugs. The common hit was the antiseptic chlorhexidine. The activity of niclosamide, carmofur, and auranofin was found against the selected methicillin-resistant S. aureus. Zidovudine was effective against colistin-resistant E. coli and carbapenem-resistant K. pneumoniae. Trifluridine, an antiviral, was effective against E. faecium. Deferoxamine mesylate inhibited the growth of XDR P. nosoerga. Drug repurposing by an in vitro screening of a drug library is a promising approach to identify effective drugs for specific bacteria.

[Effect of 2% Chlorhexidine Bathing on the Incidence of Hospital-Acquired Infection and Multidrug-Resistant Organisms in Adult Intensive Care Unit Patients: Systematic Review and Meta-Analysis]

PURPOSE

This systematic review and meta-analysis analyzed the effects of 2% chlorhexidine bathing on the incidence of hospital-acquired infection (HAI) and multidrug-resistant organisms (MDRO) in adult intensive care units.

METHODS

PubMed, CINAHL, Cochrane library, and RISS database were systematically searched, and 12 randomized studies were included in the analysis. Comprehensive Meta-Analysis version 3.0 was used to calculate the effect size using the odds ratio (OR) and a 95% confidence interval (CI). Subgroup analysis was performed according to the specific infection and intervention types.

RESULTS

In general, 2% chlorhexidine bathing has a significant effect on the incidence of HAI (OR, 0.59; 95% CI, 0.40~0.86) and MDRO (OR, 0.52; 95% CI, 0.34~0.79). Subgroup analyses show 2% chlorhexidine bathing is effective in bloodstream infections (OR, 0.51; 95% CI, 0.39~0.66) but not for urinary tract infections, ventilator-associated pneumonia infections, and Clostridium difficile infections. Moreover, 2% chlorhexidine bathing alone or its combination with other interventions has a significant effect on the incidence of HAI and MDRO (OR, 0.59; 95% CI, 0.38~0.92).

CONCLUSION

This meta-analysis reveals that 2% chlorhexidine bathing significantly reduces the incidence of HAI and MDRO in intensive care units. The effect of 2% chlorhexidine bathing on pediatric patients or patients at general wards should be further assessed as a cost-effective intervention for infection control.

Combination inhibition activity of chlorhexidine and antibiotics on multidrug-resistant Acinetobacter baumannii in vitro

Background

Chlorhexidine is a widely used disinfectant in clinical settings and a broad-spectrum antimicrobial agent effective against aerobic and anaerobic bacteria. However, disinfectant resistant or non-susceptible bacteria, including antibiotic-resistant Acinetobacter baumannii, have been found. This study aimed to develop a new technique to prevent and control A. baumannii infection in the hospital setting.

Methods

Chlorhexidine combined with minocycline, doxycycline, meropenem, imipenem, levofloxacin and ciprofloxacin were tested against the 30 multidrug-resistant and extremely drug-resistant A. baumannii clinical isolates. The checkerboard test was used to calculate the fractional inhibitory concentration index according to the minimum inhibitory concentration value for chlorhexidine combined with antibiotics.

Results

The combination of chlorhexidine with minocycline, doxycycline, meropenem, or ciprofloxacin showed synergistic responses in all clinical isolates, and more than 50% of isolates showed FICI ≤0.5. However, chlorhexidine together with imipenem or levofloxacin showed indifferent responses in 10% and 3.33% clinical isolates, respectively. In all tests, combinations of chlorhexidine with each of the above six antibiotics showed synergistic and additive effects, and inhibited the clinical isolates.

Conclusions

We concluded that, chlorhexidine combined with antibiotics could be used to control the risk of infection with A. baumannii.

Chlorhexidine Gluconate Bathing Reduces the Incidence of Bloodstream Infections in Adults Undergoing Inpatient Hematopoietic Cell Transplantation

Bloodstream infections (BSIs) occur in 20% to 45% of inpatient autologous and allogeneic hematopoietic cell transplant (HCT) patients. Daily bathing with the antiseptic chlorhexidine gluconate (CHG) has been shown to reduce the incidence of BSIs in critically ill patients, although very few studies include HCT patients or have evaluated the impact of compliance on effectiveness. We conducted a prospective cohort study with historical controls to assess the impact of CHG bathing on the rate of BSIs and gut microbiota composition among adults undergoing inpatient HCT at the Duke University Medical Center. We present 1 year of data without CHG bathing (2016) and 2 years of data when CHG was used on the HCT unit (2017 and 2018). Because not all patients adhered to CHG, patients were grouped into four categories by rate of daily CHG usage: high (>75%), medium (50% to 75%), low (1% to 49%), and none (0%). Among 192 patients, univariate trend analysis demonstrated that increased CHG usage was associated with decreased incidence of clinically significant BSI, defined as any BSI requiring treatment by the medical team (high, 8% BSI; medium, 15.2%; low, 15.6%; no CHG, 30.3%; P = .003), laboratory-confirmed BSI (LCBI; P = .03), central line-associated BSI (P = .04), and mucosal barrier injury LCBI (MBI-LCBI; P = .002). Multivariate analysis confirmed a significant effect of CHG bathing on clinically significant BSI (P = .023) and MBI-LCBI (P = .007), without consistently impacting gut microbial diversity. Benefits of CHG bathing were most pronounced with >75% daily usage, and there were no adverse effects attributable to CHG. Adherence to daily CHG bathing significantly decreases the rate of bloodstream infection following HCT.

Control Strategies for Infection Prevention in Total Joint Arthroplasty

Despite the development of newer preventative measures, the rate of infection continues to be approximately 1% for patients undergoing total joint arthroplasty (TJA). The extent of the infection can range from a mild superficial infection to a more serious periprosthetic joint infection (PJI). PJIs not only play a significant role in the clinical well-being of the TJA patient population, but also have substantial economic implications on the health care system. Several approaches are currently being used to mitigate the risk of PJI after TJA. The variety of prophylactic measures to prevent infection after TJA must be thoroughly discussed and evaluated.

The mobile dso-gene-sso element in rolling-circle plasmids of staphylococci reflects the evolutionary history of its resistance gene

The qacC and lnuA genes of Staphylococcus species were recently proposed to comprise a mobile element when residing on rolling-circle plasmids. Here we present other examples of resistance genes on staphylococcal rolling-circle plasmids, including fosB producing resistance to fosfomycin, cat resulting in resistance to chloramphenicol and cadB for resistance to the toxic heavy metal cadmium. For three of these genes (qacC, lnuA and fosB), evidence was obtained that the genes have spread between different plasmid backgrounds. The lack of mutations in qacC suggests that the spread occurred relatively recently, while the build up of mutations in lnuA and fosB suggests their mobilization occurred in the more distant past. These observations can be explained by the use of the respective antibiotics over time. However, the cat and cadB genes sequences analysed had not collected any mutations, an observation that is not completely understood but possible explanations are discussed.

SIGNIFICANCE AND IMPACT OF THE STUDY

We have analysed five resistance genes in Staphylococcus aureus that are positioned between the replication elements of rolling-circle plasmids. For three of these genes, evidence was obtained indicative of recent mobilization. The historical use of the antibiotics to which the genes produce resistance could be related to the number of mutations collected in these genes. However, two other resistance genes have not collected any mutations over time, and the reasons for this are discussed. The analyses presented provide insights into the spread and evolution of antibiotic resistance genes.

Preoperative Chlorhexidine Gluconate Use Can Increase Risk for Surgical Site Infections after Ventral Hernia Repair

BACKGROUND

There is varying evidence about the use of preoperative chlorhexidine gluconate to decrease surgical site infection for elective surgery. This intervention has never been studied in ventral hernia repair, the most common general surgery procedure in the US. We aimed to determine whether preoperative chlorhexidine gluconate decreases the risk of 30-day wound morbidity in patients undergoing ventral hernia repair.

STUDY DESIGN

All patients undergoing ventral hernia repair in the Americas Hernia Society Quality Collaborative were separated into 2 groups: 1 group received preoperative chlorhexidine scrub and the other did not. The 2 groups were evaluated for 30-day wound morbidity, including surgical site occurrence (SSO), surgical site infection (SSI), and SSO requiring procedural intervention. Statistical analysis was performed using multivariate regression analysis and propensity score modeling. Multiple factors were controlled for statistical analysis, including patient-related factors and operative factors.

RESULTS

In total, 3,924 patients were included for comparison. After multivariate logistic regression modeling, the preoperative chlorhexidine scrub group had a higher incidence of SSOs (odds ratio [OR] = 1.34; 95% CI 1.11 to 1.61) and SSIs (OR = 1.46; 95% CI 1.03 to 2.07). After propensity score modeling, the increased risk of SSO and SSI persisted (SSO: OR = 1.39; 95% CI 1.15 to 1.70; SSI: OR = 1.45; 95% CI 1.011 to 2.072, respectively).

CONCLUSIONS

Prehospital chlorhexidine gluconate scrub appears to increase the risk of 30-day wound morbidity in patients undergoing ventral hernia repair. These findings suggest that the generalized use of prehospital chlorhexidine might not be desirable for all surgical populations.