Sensitivity of urine-grown cells of Providencia stuartii to antiseptics

A case report of three people experiencing intractable autonomic dysreflexia following instillation of Uro-Tainer® Polyhexanide 0.02

INTRODUCTION

Historically, bladder washouts were used to instil therapeutic reagents directly into the bladder. This practice has expanded to include instillation of solutions that deal with catheter issues such as encrustation or formation of bio-film. They appear to provide a promising strategy for people with long term catheters. These products are readily available to purchase, but there is concern that people are using these solutions without a complete understanding of the purpose for the rinse and without clinical guidance to monitor response to treatment.

CASE PRESENTATION

These case studies include three people living with spinal cord injury (SCI) who developed severe autonomic dysreflexia (AD) when a catheter rinse was carried out using a particular solution. Each of the cases developed immediate and, in some cases, intractable AD requiring further intervention to resolve symptoms.

DISCUSSION

Catheter-associated urinary tract infection is a significant cause of morbidity and mortality in people living with SCI. Long-term catheters provide a vector for opportunistic micro-organisms to form bio-film and create an environment that promotes formation of struvite calculi, thus increasing the risk of chronic catheter blockage and urinary tract infection. Whilst these solutions are used to reduce these risks, they also pose additional risks to people susceptible to AD. These cases highlight the need for judicious patient selection and clinical oversight and management of adverse events when using catheter rinse solutions in certain people living with SCI. This is supported by a decision-making algorithm and a response to AD algorithm. This case report was prepared following the CARE Guidelines (supplementary file 1).

Antimicrobial stewardship of antiseptics that are pertinent to wounds: the need for a united approach

Long before the nature of infection was recognized, or the significance of biofilms in delayed healing was understood, antimicrobial agents were being used in wound care. In the last 70 years, antibiotics have provided an effective means to control wound infection, but the continued emergence of antibiotic-resistant strains and the documented antibiotic tolerance of biofilms has reduced their effectiveness. A range of wound dressings containing an antimicrobial (antibiotic or non-antibiotic compound) has been developed. Whereas standardized methods for determining the efficacy of non-antibiotic antimicrobials in bacterial suspension tests were developed in the early twentieth century, standardized ways of evaluating the efficacy of antimicrobial dressings against microbial suspensions and biofilms are not available. Resistance to non-antibiotic antimicrobials and cross-resistance with antibiotics has been reported, but consensus on breakpoints is absent and surveillance is impossible. Antimicrobial stewardship is therefore in jeopardy. This review highlights these difficulties and in particular the efficacy of current non-antibiotic antimicrobials used in dressings, their efficacy, and the challenges of translating in vitro efficacy data to the efficacy of dressings in patients. This review calls for a unified approach to developing standardized methods of evaluating antimicrobial dressings that will provide an improved basis for practitioners to make informed choices in wound care.

Reduction in chlorhexidine efficacy against multi-drug-resistant Acinetobacter baumannii international clone II

BACKGROUND

Nosocomial infections caused by Acinetobacter baumannii international clone II (IC II) can cause severe clinical outcomes.

AIM

Differential evaluation of bactericidal efficacy of chlorhexidine gluconate (CHX) and benzethonium chloride (BZT) disinfectants against IC II and non-IC II isolates.

METHODS

Minimum inhibitory concentrations (MICs) of CHX and BZT were determined for 137 A. baumannii IC II, 99 non-IC II and 69 non-baumannii isolates, further classified according to MIC values into disinfectant-reduced susceptible (DRS) and disinfectant-susceptible (DS) groups. Time-kill curves and minimum bactericidal concentrations (MBCs) were evaluated for representative isolates in each group.

RESULTS

CHX and BZT MIC₉₀s for IC II isolates were 100 and 175mg/L, respectively, but those for non-IC II and non-baumannii isolates were <100mg/L. Nevertheless, time-kill curves indicated that CHX and BZT reduced live bacterial cell number by 5 log₁₀ for IC II and non-IC II isolates within 30s when used at 1000mg/L, comparable to practical use concentrations. CHX MBC at 30s was 1000mg/L for IC II and non-IC II isolates, and was not influenced by addition of 3% bovine serum albumin (BSA); BZT MBC at 30s was 100mg/L without BSA and increased up to 500mg/L upon addition of BSA. No significant differences in BSA were found between DRS and DS isolates.

CONCLUSION

CHX and BZT were effective against Acinetobacter spp. including IC II at a concentration of 1000mg/L and exposure for at least 30s, but their concentrations should be considered carefully to ensure sufficient effects in both clinical and healthcare settings.

Is reduced susceptibility to disinfectants and antiseptics a risk in healthcare settings? A point/counterpoint review

BACKGROUND

Given the breadth and depth of antiseptic use, it is surprising how few large-scale studies have been undertaken into the consequences of their use, particularly in clinical practice. Depending on your point of view, this may either reflect an assurance that reduced susceptibility to antiseptics, and notably whether this confers cross-resistance to systemically administered antimicrobial agents, is not an issue of concern, or relative ignorance about the potential threat.

AIM

This point/counterpoint review offers a differentiated perspective and possible answers to the question, 'Should we be worried about reduced susceptibility to disinfectants and antiseptics in healthcare settings?'.

METHODS

This topic was the subject of a debate by MHW (point) and SH (counterpoint) during the SHEA Spring Conference 2013: Advancing healthcare epidemiology and the role of the environment, held in Atlanta, GA, USA on 4(th) May 2013. This review is a general representation of the main themes presented during the debate, rather than a systematic review of the literature.

FINDINGS

There are examples of reduced susceptibility to antiseptics in clinical practice; however, to date, there is no strong evidence that reduced susceptibility to antiseptics is a major clinical problem. Given the growing number of potential indications for use of biocidal active ingredients, the potential for emergence of reduced susceptibility remains a concern.

CONCLUSIONS

Changes in the clinical use of antiseptics should be matched with surveillance studies to understand whether there are unintended microbiological or clinical consequences, including the selection of bacterial strains that can survive exposure to antiseptics.

Epidemiologic background of hand hygiene and evaluation of the most important agents for scrubs and rubs

The etiology of nosocomial infections, the frequency of contaminated hands with the different nosocomial pathogens, and the role of health care workers' hands during outbreaks suggest that a hand hygiene preparation should at least have activity against bacteria, yeasts, and coated viruses. The importance of efficacy in choosing the right hand hygiene product is reflected in the new Centers for Disease Control and Prevention guideline on hand hygiene (J. M. Boyce and D. Pittet, Morb. Mortal. Wkly. Rep. 51:1-45, 2002). The best antimicrobial efficacy can be achieved with ethanol (60 to 85%), isopropanol (60 to 80%), and n-propanol (60 to 80%). The activity is broad and immediate. Ethanol at high concentrations (e.g., 95%) is the most effective treatment against naked viruses, whereas n-propanol seems to be more effective against the resident bacterial flora. The combination of alcohols may have a synergistic effect. The antimicrobial efficacy of chlorhexidine (2 to 4%) and triclosan (1 to 2%) is both lower and slower. Additionally, both agents have a risk of bacterial resistance, which is higher for chlorhexidine than triclosan. Their activity is often supported by the mechanical removal of pathogens during hand washing. Taking the antimicrobial efficacy and the mechanical removal together, they are still less effective than the alcohols. Plain soap and water has the lowest efficacy of all. In the new Centers for Disease Control and Prevention guideline, promotion of alcohol-based hand rubs containing various emollients instead of irritating soaps and detergents is one strategy to reduce skin damage, dryness, and irritation. Irritant contact dermatitis is highest with preparations containing 4% chlorhexidine gluconate, less frequent with nonantimicrobial soaps and preparations containing lower concentrations of chlorhexidine gluconate, and lowest with well-formulated alcohol-based hand rubs containing emollients and other skin conditioners. Too few published data from comparative trials are available to reliably rank triclosan. Personnel should be reminded that it is neither necessary nor recommended to routinely wash hands after each application of an alcohol-based hand rub. Long-lasting improvement of compliance with hand hygiene protocols can be successful if an effective and accessible alcohol-based hand rub with a proven dermal tolerance and an excellent user acceptability is supplied, accompanied by education of health care workers and promotion of the use of the product.

Efficacy of hand disinfectants against vancomycin-resistant enterococci in vitro

Vancomycin-resistant enterococci (VRE) may be spread within a hospital via the contaminated hands of the healthcare worker. Effective hand disinfectants are necessary to break chains of transmission. We determined the bactericidal activity of 1-propanol, chlorhexidine digluconate (0.5 and 4%). Sterillium (45% 2-propanol, 30% 1-propanol and 0.2% mecetronium etilsulphate), Skinsept F (70% 2-propanol, 0.5% chlorhexidine digluconate and 0.45% hydrogen peroxide) and Hibisol (70% 2-propanol and 0.5% chlorhexidine gluconate) against 11 clonally distinct enterococcal isolates in a quantitative suspension test. Four isolates were vancomycin susceptible, four were vanA and the remainder vanB positive. Eight isolates were identified as Enterococcus faecium, two as Enterococcus faecalis and one as Enterococcus gallinarum. The investigator was blinded to the species and the genotype. Four parallel experiments were carried out for each isolate, each preparation, each dilution and each reaction time. 1-Propanol (60%), Sterillium, Skinsept F and Hibisol were all highly bactericidal after 15 and 30 s against VRE and vancomycin-susceptible enterococci (VSE) with reduction factors (RF) > 6.4, even in dilution of 50% (v/v). No significant difference was observed between vanA isolates, vanB isolates and VSE. Chlorhexidine digluconate (0.5% and 4%) was found to be less bactericidal after 30, 60 and 300 sec (RF < or = 2.5). The vanB genotype isolates were found to be significantly more susceptible to chlorhexidine (0.5%) than the vanA isolates (60 sec; one-way ANOVA model; P = 0.05). After 300 sec the vanB genotype isolates were found to be significantly more susceptible to chlorhexidine (0.5%) than the other two genotype isolates (P = 0.016). The vanA isolates were found to be significantly more susceptible to chlorhexidine (4%) than the vanB isolates (300 s; P = 0.024). E. faecium was found to be less susceptible to chlorhexidine than E. faecalis at all concentrations and reaction times, but significant differences between RF were only observed at 60 sec for both chlorhexidine concentrations (P < 0.05; t-test for independent samples). Propanol is much more effective against enterococci than chlorhexidine and combination of the two may be useful in providing an immediate and long lasting effect.

The sensitizing potency of Euxyl K 400 and its components 1,2-dibromo-2,4-dicyanobutane and 2-phenoxyethanol

Using a modified FCA (Freund's complete adjuvant) procedure, the sensitizing capacity of Euxyl K 400 and its ingredients, 1,2-dibromo-2,4-dicyanobutane and 2-phenoxyethanol, has been studied in guinea pigs. The experiments demonstrate that a distinct but weak sensitizing potency exists for Euxyl K 400 and dibromodicyanobutane. Phenoxyethanol remained almost negative. These results are in good accordance with the low number of cases of allergic contact dermatitis due to Euxyl K 400 and dibromodicyanobutane described since their introduction on the market. Cases of phenoxyethanol contact allergy have been published hitherto only 4x in the medical literature.

Assessment of antiseptic bladder washout procedures using a physical model of the catheterised bladder

A simple physical model of the catheterised bladder has been used to assess the activities of antiseptic agents that have been recommended as bladder instillations in the treatment of urinary tract infections in patients with indwelling catheters. The activities of povidone-iodine, phenoxyethanol, chlorhexidine, chlorhexidine supplemented with EDTA + Tris, noxythiolin and neomycin were examined against selected species of uropathogens. Except for phenoxyethanol against Pv. stuartii and possibly Ps. aeruginosa, single applications of these antibacterials for 30 min were not effective in sterilising urine in the artificial bladder. However, a second application 1 h later of phenoxyethanol but not chlorhexidine or povidone-iodine did eradicate Ps. aeruginosa. It is suggested that bacteria growing as a film on the bladder wall are particularly resistant to antimicrobials.

Chlorhexidine resistance among bacteria isolated from urine of catheterized patients

Seventy-four of 155 catheter specimens of urine yielded organisms resistant to chlorhexidine. The inhibitory effect of urine against chlorhexidine is reported.

The resistance of urinary tract pathogens to chlorhexidine bladder washouts

Isolates of Providencia stuartii, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae and Streptococcus faecalis from urinary-tract infections in spinally-injured patients together with Escherichia coli 10418 were challenged with chlorhexidine (200 mg l-1) in a model of a catheterized bladder under conditions which simulate the bladder washout technique. All species survived the antiseptic. Organisms growing on the wall of the bladder model appeared to be particularly resistant and electron microscopy showed that these cells were embedded in a protective glycocalyx. The effect of chlorhexidine bladder washouts on the bacterial flora in the urine of patients was also observed and shown to be minimal and temporary. Examination of urinary sediments from patients revealed the presence of micro-colonies of bacteria embedded in a polysaccharide matrix. We conclude that bladder washouts with chlorhexidine are not likely to eliminate established infections with organisms that occur in patients with indwelling bladder catheters.

Antiseptic and antibiotic resistance in gram-negative bacteria causing urinary tract infection in spinal cord injured patients

Fifty-seven isolates of Gram-negative bacterial species from urinary tract infections in spinal cord injured patients were tested for their sensitivity to chlorhexidine, cetrimide, glutaraldehyde, phenyl mercuric nitrate (PMN), a phenolic disinfectant (Hycolin) and a proprietary antiseptic containing a mixture of picloxydine, octylphenoxypolyethoxyethanol and benzalkonium chloride (Resiguard). None of the isolates were resistant to glutaraldehyde, Hycolin or PMN but a substantial percentage were resistant to chlorhexidine (44 per cent), cetrimide (26 per cent) and Resiguard (42 per cent). The resistant organisms were members of the genera Proteus, Providencia and Pseudomonas and they were also generally resistant to five, six or seven antibiotics. Significant correlations were observed between multiplicity of antibiotic resistance and the minimum inhibitory concentrations of the three cationic antiseptics. It is suggested that an antiseptic policy for the bladder management of spinal cord injured patients that relies on the extensive use of cationic agents might lead to the selection of a flora of notoriously drug-resistant species.

Antiseptic and antibiotic resistance in Gram-negative bacteria causing urinary tract infection

A collection of 802 isolates of Gram-negative bacteria causing urinary tract infections was made from general practice, antenatal clinics, and local hospitals. The organisms were tested for their sensitivity to chlorhexidine, cetrimide, glutaraldehyde, phenyl mercuric nitrate, a phenolic formulation, and a proprietary antiseptic containing a mixture of picloxydine, octyl phenoxy polyethoxyethanol, and benzalkonium chloride. Escherichia coli, the major species isolated, proved to be uniformly sensitive to these agents. Approximately 10% of the total number of isolates, however, exhibited a degree of resistance to the cationic agents. These resistant organisms were members of the genera Proteus, Providencia, and Pseudomonas; they were also generally resistant to five, six, or seven antibiotics. It is proposed therefore that an antiseptic policy which involves the intensive use of cationic antiseptics might lead to the selection of a flora of notoriously drug-resistant species.