Antiseptic impregnated endotracheal tubes for the prevention of bacterial colonization

Co-immobilization of Ciprofloxacin and Chlorhexidine as a Broad-Spectrum Antimicrobial Dual-Drug Coating for Poly(vinyl chloride) (PVC)-Based Endotracheal Tubes

The endotracheal tube (ETT) affords support for intubated patients, but the increasing incidence of ventilator-associated pneumonia (VAP) is jeopardizing its application. ETT surfaces promote (poly)microbial colonization and biofilm formation, with a heavy burden for VAP. Devising safe, broad-spectrum antimicrobial materials to tackle the ETT bioburden is needful. Herein, we immobilized ciprofloxacin (CIP) and/or chlorhexidine (CHX), through polydopamine (pDA)-based functionalization, onto poly(vinyl chloride) (PVC) surfaces. These surfaces were characterized regarding physicochemical properties and challenged with single and polymicrobial cultures of VAP-relevant bacteria (Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis) and fungi (Candida albicans). The coatings imparted PVC surfaces with a homogeneous morphology, varied wettability, and low roughness. The antimicrobial immobilization via pDA chemistry was still evidenced by infrared spectroscopy. Coated surfaces exhibited sustained CIP/CHX release, retaining prolonged (10 days) activity. CIP/CHX-coated surfaces evidencing no A549 lung cell toxicity displayed better antibiofilm outcomes than CIP or CHX coatings, preventing bacterial attachment by 4.1-7.2 Log10 CFU/mL and modestly distressingC. albicans. Their antibiofilm effectiveness was endured toward polymicrobial consortia, substantially inhibiting the adhesion of the bacterial populations (up to 8 Log10 CFU/mL) within the consortia in dual- and even inP. aeruginosa/S. aureus/C. albicans triple-species biofilms while affecting fungal adhesion by 2.7 Log10 CFU/mL (dual consortia) and 1 Log10 CFU/mL (triple consortia). The potential of the dual-drug coating strategy in preventing triple-species adhesion and impairing bacterial viability was still strengthened by live/dead microscopy. The pDA-assisted CIP/CHX co-immobilization holds a safe and robust broad-spectrum antimicrobial coating strategy for PVC-ETTs, with the promise laying in reducing VAP incidence.

Antimicrobial Solutions for Endotracheal Tubes in Prevention of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia is one of the most frequently encountered hospital infections and is an essential issue in the healthcare field. It is usually linked to a high mortality rate and prolonged hospitalization time. There is a lack of treatment, so alternative solutions must be continuously sought. The endotracheal tube is an indwelling device that is a significant culprit for ventilator-associated pneumonia because its surface can be colonized by different types of pathogens, which generate a multispecies biofilm. In the paper, we discuss the definition of ventilator-associated pneumonia, the economic burdens, and its outcomes. Then, we present the latest technological solutions for endotracheal tube surfaces, such as active antimicrobial coatings, passive coatings, and combinatorial methods, with examples from the literature. We end our analysis by identifying the gaps existing in the present research and investigating future possibilities that can decrease ventilator-associated pneumonia cases and improve patient comfort during treatment.

Effect of clove mouthwash on the incidence of ventilator-associated pneumonia in intensive care unit patients: a comparative randomized triple-blind clinical trial

OBJECTIVES

Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in intensive care units (ICUs), and the use of mouthwash is the most widely used method to prevent its incidence. The aim of this study was to investigate effect of clove mouthwash on the incidence of VAP in the ICU.

MATERIALS AND METHODS

This comparative, randomized, triple-blind, clinical trial was conducted on 168 eligible ICU patients at Kosar Hospital in Semnan, Iran, during 2021-2022, who were divided into intervention and control groups using random blocks. The intervention group received clove extract mouthwash at 6.66% concentration, and the control group received chlorhexidine 0.2% twice a day for 5 days (routine care). Data were collected using a demographic questionnaire, and disease severity was measured based on the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, oral health status was examined using the Beck Oral Assessment Scale (BOAS), and VAP diagnosis was made based on the Modified Clinical Pulmonary Infection Score (MCPIS).

RESULTS

Before the intervention, there was no significant difference in disease severity (p = 0.412) and oral health status (p = 0.239) between the patients in the two groups. After the intervention, 20.2% of the patients in the intervention group and 41.7% of those in the control group acquired VAP. The risk of VAP was 2.06 times higher in the control group than in the intervention group (p = 0.005, 95% CI: 1.26-3.37, RR = 2.06), but the severity of VAP did not differ significantly between the patients in the two groups (p = 0.557).

CONCLUSION

The findings showed that clove mouthwash reduces the incidence of VAP significantly.

CLINICAL RELEVANCE

Clove mouthwash can be used as a simple and low-cost method to prevent VAP in ICU patients.

Antimicrobial materials for endotracheal tubes: A review on the last two decades of technological progress

Ventilator-associated pneumonia (VAP) is an unresolved problem in nosocomial settings, remaining consistently associated with a lack of treatment, high mortality, and prolonged hospital stay. The endotracheal tube (ETT) is the major culprit for VAP development owing to its early surface microbial colonization and biofilm formation by multiple pathogens, both critical events for VAP pathogenesis and relapses. To combat this matter, gradual research on antimicrobial ETT surface coating/modification approaches has been made. This review provides an overview of the relevance and implications of the ETT bioburden for VAP pathogenesis and how technological research on antimicrobial materials for ETTs has evolved. Firstly, certain main VAP attributes (definition/categorization; outcomes; economic impact) were outlined, highlighting the issues in defining/diagnosing VAP that often difficult VAP early- and late-onset differentiation, and that generate misinterpretations in VAP surveillance and discrepant outcomes. The central role of the ETT microbial colonization and subsequent biofilm formation as fundamental contributors to VAP pathogenesis was then underscored, in parallel with the uncovering of the polymicrobial ecosystem of VAP-related infections. Secondly, the latest technological developments (reported since 2002) on materials able to endow the ETT surface with active antimicrobial and/or passive antifouling properties were annotated, being further subject to critical scrutiny concerning their potentialities and/or constraints in reducing ETT bioburden and the risk of VAP while retaining/improving the safety of use. Taking those gaps/challenges into consideration, we discussed potential avenues that may assist upcoming advances in the field to tackle VAP rampant rates and improve patient care. STATEMENT OF SIGNIFICANCE: The use of the endotracheal tube (ETT) in patients requiring mechanical ventilation is associated with the development of ventilator-associated pneumonia (VAP). Its rapid surface colonization and biofilm formation are critical events for VAP pathogenesis and relapses. This review provides a comprehensive overview on the relevance/implications of the ETT biofilm in VAP, and on how research on antimicrobial ETT surface coating/modification technology has evolved over the last two decades. Despite significant technological advances, the limited number of gathered reports (46), highlights difficulty in overcoming certain hurdles associated with VAP (e.g., persistent colonization/biofilm formation; mechanical ventilation duration; hospital length of stay; VAP occurrence), which makes this an evolving, complex, and challenging matter. Challenges and opportunities in the field are discussed.

Antimicrobial polymer modifications to reduce microbial bioburden on endotracheal tubes and ventilator associated pneumonia

Hospital associated infections (HAIs), infections acquired by patients during care in a hospital, remain a prevalent issue in the healthcare field. These infections often occur with the use of indwelling medical devices, such as endotracheal tubes (ETTs), that can result in ventilator-associated pneumonia (VAP). When examining the various routes of infection, VAP is associated with the highest incidence, rate of morbidity, and economic burden. Although ETTs are essential for the survival of patients requiring mechanical ventilation, their use comes with complications. The presence of an ETT in the airway impairs physiological host defense mechanisms for clearance of pathogens and provides a platform for oropharynx microorganism transport to the sterile tracheobronchial network. Antibiotics are administered to treat lower respiratory infections; however, they are not always effective and consequently can result in increased antibiotic resistance. Prophylactic approaches by altering the surface of ETTs to prevent the establishment and growth of bacteria have exhibited promising results. In addition, passive surface modifications that prevent bacterial establishment and growth, or active coatings that possess a bactericidal effect have also proven effective. In this review we aim to highlight the importance of preventing biofilm establishment on indwelling medical devices, focusing on ETTs. We will investigate successful antimicrobial modifications to ETTs and the future avenues that will ultimately decrease HAIs and improve patient care. STATEMENT OF SIGNIFICANCE: Infections that occur with indwelling medicals devices remain a constant concern in the medical field and can result in hospital-acquired infections. Specifically, ventilator associated pneumonia (VAP) occurs with the use of an endotracheal tube (ETT). Infections often require use of antibiotics and can result in patient mortality. Our review includes a summary of the recent collective work of antimicrobial ETT modifications and potential avenues for further investigations in an effort to reduce VAP associated with ETTs. Polymer modifications with antibacterial nature have been developed and tested; however, a focus on ETTs is lacking and clinical availability of new antimicrobial ETT devices is limited. Our collective work shows the successful and prospective applications to the surfaces of ETTs that can support researchers and physicians to create safer medical devices.

Ventilator-Associated Pneumonia: A Review

Ventilator-associated pneumonia is the most frequent intensive care unit (ICU)-related infection in patients requiring mechanical ventilation. In contrast to other ICU-related infections, which have a low mortality rate, the mortality rate for ventilator-associated pneumonia ranges from 20% to 50%. These clinically significant infections prolong duration of mechanical ventilation and ICU length of stay, underscoring the financial burden these infections impose on the health care system. The causes of ventilator-associated pneumonia are varied and differ across different patient populations and different types of ICUs. This varied presentation underscores the need for the intensivist treating the patient with ventilator-associated pneumonia to have a clear knowledge of the ambient microbiologic flora in their ICU. Prevention of this disease process is of paramount importance and requires a multifaceted approach. Once a diagnosis of ventilator-associated pneumonia is suspected, early broad-spectrum antibiotic administration decreases morbidity and mortality and should be based on knowledge of the sensitivities of common infecting organisms in the ICU. De-escalation of therapy, once final culture results are available, is necessary to minimize development of resistant pathogens. Duration of therapy should be based on the patient’s clinical response, and every effort should be made to minimize duration of therapy, thus further minimizing the risk of resistance.

Effect of nebulized eucalyptus on contamination of microbial plaque of endotracheal tube in ventilated patients

Background:

Formation of biofilm and bacterial colonization within the endotracheal tube (ETT) are significant sources of airway contamination and play a role in the development of ventilator-associated pneumonia (VAP). This study was conducted to examine the effect of nebulized eucalyptus (NE) on bacterial colonization of ETT biofilm.

Materials and Methods:

We performed a randomized clinical trial in three intensive care units (ICUs) of an educational hospital. Seventy intubated patients were selected and randomly divided into intervention (n = 35) and control (n = 35) groups. The intervention group received 4 ml (5%) of eucalyptus in 6 ml normal saline every 8 h. The placebo group received only 10 ml of normal saline in the same way. On extubation, the interior of the tube was immediately sampled using a sterile swab for standard microbiological analysis. Chi-square and Fisher's exact tests were used for statistical analysis in SPSS. P values less than 0.05 were considered statistically significant.

Results:

In both samples, Klebsiella pneumoniae and Acinetobacter baumannii were the most frequently isolated bacteria. In the control group, heavy colonization was greater than in the intervention group (P = 0.002). The frequency of isolation of K. pneumoniae in the intervention group was lower than in the control group (P < 0.001). However, there was no difference between the two groups in other isolated bacteria.

Conclusions:

NE can reduce microbial contamination of the endotracheal tube biofilm in ventilated patients. Moreover, K. pneumoniae was the most sensitive to NE.

The use of 2% chlorhexidine gel and toothbrushing for oral hygiene of patients receiving mechanical ventilation: effects on ventilator-associated pneumonia

Objective

To evaluate the effects of oral chlorhexidine hygiene with toothbrushing on the rate of ventilator-associated pneumonia in a mixed population of critically ill patients under prolonged mechanical ventilation.

Methods

Prospective, randomized, and placebo-controlled pilot study. Patients who were receiving mechanical ventilation, had been admitted less than 24 hours prior, and were anticipated to require mechanical ventilation for more than 72 hours were included in the study. The patients were randomly divided into one of the following groups: chlorhexidine hygiene with toothbrushing or a placebo group (gel with the same color and consistency and toothbrushing).

Results

The planned interim analysis was conducted using 52 patients, and the study was terminated prematurely. In total, 28 patients were included in the chlorhexidine / toothbrushing group, and 24 patients were included in the placebo group. Ventilator-associated pneumonia occurred in 45.8% of the placebo group and in 64.3% of the chlorhexidine hygiene with toothbrushing group (RR=1.4; 95% CI=0.83-2.34; p=0.29).

Conclusion

Because the study was terminated due to futility, it was not possible to evaluate the impact of oral hygiene using 2% chlorhexidine and toothbrushing on the incidence of ventilator-associated pneumonia in this heterogeneous population of critical patients receiving long-term mechanical ventilation, and no beneficial effect was observed for this intervention.

Silver-coated endotracheal tubes for prevention of ventilator-associated pneumonia in critically ill patients

BACKGROUND

Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in intubated and mechanically ventilated patients. Endotracheal tubes (ETTs) appear to be an independent risk factor for VAP. Silver-coated ETTs slowly release silver cations. It is these silver ions that appear to have a strong antimicrobial effect. Because of this antimicrobial effect of silver, silver-coated ETTs could be an effective intervention to prevent VAP in people who require mechanical ventilation for 24 hours or longer.

OBJECTIVES

Our primary objective was to investigate whether silver-coated ETTs are effective in reducing the risk of VAP and hospital mortality in comparison with standard non-coated ETTs in people who require mechanical ventilation for 24 hours or longer. Our secondary objective was to ascertain whether silver-coated ETTs are effective in reducing the following clinical outcomes: device-related adverse events, duration of intubation, length of hospital and intensive care unit (ICU) stay, costs, and time to VAP onset.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014 Issue 10, MEDLINE, EMBASE, EBSCO CINAHL, and reference lists of trials. We contacted corresponding authors for additional information and unpublished studies. We did not impose any restrictions on the basis of date of publication or language. The date of the last search was October 2014.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) and quasi-randomized trials that evaluated the effects of silver-coated ETTs or a combination of silver with any antimicrobial-coated ETTs with standard non-coated ETTs or with other antimicrobial-coated ETTs in critically ill people who required mechanical ventilation for 24 hours or longer. We also included studies that evaluated the cost-effectiveness of silver-coated ETTs or a combination of silver with any antimicrobial-coated ETTs.

DATA COLLECTION AND ANALYSIS

Two review authors (GT, HV) independently extracted the data and summarized study details from all included studies using the specially designed data extraction form. We used standard methodological procedures expected by The Cochrane Collaboration. We performed meta-analysis for outcomes when possible.

MAIN RESULTS

We found three eligible randomized controlled trials, with a total of 2081 participants. One of the three included studies did not mention the amount of participants and presented no outcome data. The 'Risk of bias' assessment indicated that there was a high risk of detection bias owing to lack of blinding of outcomes assessors, but we assessed all other domains to be at low risk of bias. Trial design and conduct were generally adequate, with the most common areas of weakness in blinding. The majority of participants were included in centres across North America. The mean age of participants ranged from 61 to 64 years, and the mean duration of intubation was between 3.2 and 7.7 days. One trial comparing silver-coated ETTs versus non-coated ETTs showed a statistically significant decrease in VAP in favour of the silver-coated ETT (1 RCT, 1509 participants; 4.8% versus 7.5%, risk ratio (RR) 0.64, 95% confidence interval (CI) 0.43 to 0.96; number needed to treat for an additional beneficial outcome (NNTB) = 37; low-quality evidence). The risk of VAP within 10 days of intubation was significantly lower with the silver-coated ETTs compared with non-coated ETTs (1 RCT, 1509 participants; 3.5% versus 6.7%, RR 0.51, 95% CI 0.31 to 0.82; NNTB = 32; low-quality evidence). Silver-coated ETT was associated with delayed time to VAP occurrence compared with non-coated ETT (1 RCT, 1509 participants; hazard ratio 0.55, 95% CI 0.37 to 0.84). The confidence intervals for the results of the following outcomes did not exclude potentially important differences with either treatment. There were no statistically significant differences between groups in hospital mortality (1 RCT, 1509 participants; 30.4% versus 26.6%, RR 1.09, 95% CI 0.93 to 1.29; low-quality evidence); device-related adverse events (2 RCTs, 2081 participants; RR 0.65, 95% CI 0.37 to 1.16; low-quality evidence); duration of intubation; and length of hospital and ICU stay. We found no clinical studies evaluating the cost-effectiveness of silver-coated ETTs.

AUTHORS' CONCLUSIONS

This review provides limited evidence that silver-coated ETT reduces the risk of VAP, especially during the first 10 days of mechanical ventilation.

Insights on the role of antimicrobial cuffed endotracheal tubes in preventing transtracheal transmission of VAP pathogens from an in vitro model of microaspiration and microbial proliferation

We developed an in vitro model to evaluate the effect of different cuffed endotracheal tubes (ETTs) on transtracheal transmission of ventilator-associated pneumonia (VAP) pathogens along external surfaces of ETTs. The model independently assessed the relative contributions of microbial proliferation to the distal tip and microaspiration of contaminated secretions past the cuff by testing in three modes: microaspiration only, microbial proliferation only, and simultaneous microaspiration and microbial proliferation. We evaluated transmission of methicillin resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PA) in the presence of a standard ETT; a soft, tapered cuff ETT with subglottic suctioning; and a novel antimicrobial gendine (combination of gentian violet and chlorhexidine) ETT in the model. In the microaspiration only mode, when leakage past the cuff occurred quickly, no ETT prevented transmission. When microaspiration was delayed, the gendine ETT was able to completely disinfect the fluid above the cuff and thereby prevent transmission of pathogens. In microbial proliferation only mode, the gendine ETT was the sole ETT that prevented transmission. With both mechanisms simultaneously available, transmission was dependent on how long microaspiration was delayed. Potent antimicrobial ETTs, such as a gendine ETT, can make unique contributions to prevent VAP when microaspiration is gradual.

Respiratory therapy device modifications to prevent ventilator-associated pneumonia

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is a controversial entity in the field of critical care. After years of research and significant efforts from regulatory agencies and hospitals, this complication is still frequently affecting mechanically ventilated patients, making VAP an active battleground for research. As a result, several preventive measures have recently been tested in experimental and clinical trials. Our interest is focused on those innovations related to the endotracheal tube (ETT).

RECENT FINDINGS

Four ETT-related VAP causative mechanisms are reviewed, together with different associated potential solutions. Technologies such as the subglottic secretion drainage and the Mucus Slurper have been studied to eliminate subglottic secretion pooling. Novel designs for the cuff and the management of its pressure may avoid leakage. Antimicrobial coatings can prevent endoluminal biofilm formation, whereas using an ETT cleaning device may also be beneficial. Finally, preserving the tracheal ciliary function will keep our best physiologic protection active.

SUMMARY

VAP prevention strategies are a continuously evolving field. Being able to identify the most valuable ideas needs a deep understanding of the disease pathophysiology. The role of the ETT is crucial and there is need for our standards of care to improve. This may soon be possible with newer technologies becoming increasingly available to clinicians.

Impact of biocides on biofilm formation by methicillin-resistant Staphylococcus aureus (ST239-SCCmecIII) isolates

Procedures of sterilization and disinfection are essential to ensure that medical and surgical instruments will not transmit infectious pathogens to patients. In the present paper, we tested the residual effect of these compounds on biofilm formation and its efficiency in disrupting preformed biofilms using methicillin-resistant Staphylococcus aureus (MRSA) isolates of the lineage ST239-SCCmecIII. All compounds examined, except 70% alcohol, caused a significant impairment in biofilm formation with concomitant inhibition of cell growth. Among the compounds examined, 10% povidone-iodine (PVP-I) was the only antiseptic that exhibited more than 90% reduction of both biofilm formation and dispersion. In the group of sterilants and disinfectants, a formulation containing 7% hydrogen peroxide and 0.2% peracetic acid (HP-PA), and sodium hypochlorite with 1% active chlorine (NaOCl) were equally effective.

Silver-coated endotracheal tube versus non-coated endotracheal tube for preventing ventilator-associated pneumonia among adults: a systematic review of randomized controlled trials

OBJECTIVE

To compare the effects of using silver-coated endotracheal tube (ETT) versus non-coated ETT on the incidence of ventilator-associated pneumonia (VAP) and mortality in adult patients.

METHOD

We searched MEDLINE, the Cochrane Library, EMBASE, and the Chinese Biomedical Literature Database from inception to June 30, 2011. We also retrieved the reference lists of included studies and reviews. Randomized controlled trials (RCTs) comparing silver-coated ETTs versus non-coated ETTs were included. We pooled the results using a random-effect model and conducted subgroup analyses and sensitivity analyses to address the heterogeneity between studies.

RESULTS

We identified two eligible RCTs with a total of 1630 participants. The studies were of high quality according to Cochrane Collaboration's tool for assessing risk of bias. Compared with non-coated ETTs, silver-coated ETTs resulted in lower incidence of VAP (RR=0.64, 95% CI 0.43 to 0.96), device-related adverse events (RR=0.53, 95% CI 0.32 to 0.88), and microbiologic burden (≥10,000 CFU/mL: 0.64, 0.48 to 0.86; ≥100,000 CFU/mL: 0.62, 0.43 to 0.89). However, there was no significant difference in total mortality (RR=1.14, 95% CI 0.99 to 1.30).

CONCLUSION

The limited evidence from meta-analysis of two RCTs showed that using silver-coated ETTs reduced the incidence of VAP, microbiologic burden, and device-related adverse events among adult patients. Additional rigorous randomized trials are needed to confirm these findings.

Reduction of Endotracheal Tube Biofilms Using Antimicrobial Photodynamic Therapy

BACKGROUND: Ventilator-associated pneumonia (VAP) is reported to occur in 12 to 25% of patients who require mechanical ventilation with a mortality rate of 24 to 71%. The endotracheal (ET) tube has long been recognized as a major factor in the development of VAP since biofilm harbored within the ET tube become dislodged during mechanical ventilation and have direct access to the lungs. The objective of this study was to demonstrate the safety and effectiveness of a non-invasive antimicrobial photodynamic therapy (aPDT) treatment method of eradicating antibiotic resistant biofilms from ET tubes in an in vitro model. METHODS: Antibiotic resistant polymicrobial biofilms of Pseudomonas aerugenosa and MRSA were grown in ET tubes and treated, under standard ventilator conditions, with a methylene blue (MB) photosensitizer and 664nm non-thermal activating light. Cultures of the lumen of the ET tube were obtained before and after light treatment to determine efficacy of biofilm reduction. RESULTS: The in vitro ET tube biofilm study demonstrated that aPDT reduced the ET tube polymicrobial biofilm by >99.9% (p<0.05%) after a single treatment. CONCLUSIONS: MB aPDT can effectively treat polymicrobial antibiotic resistant biofilms in an ET tube.

Endotracheal tube biofilm inoculation of oral flora and subsequent colonization of opportunistic pathogens

Endotracheal (ET) tubes accumulate a biofilm during use, which can harbor potentially pathogenic microorganisms. The enrichment of pathogenic strains in the biofilm may lead to ventilator-associated pneumonia (VAP) with an increased morbidity rate in intensive care units. We used quantitative PCR (qPCR) and gene surveys targeting 16S rRNA genes to quantify and identify the bacterial community to detect fastidious/nonculturable organisms present among extubated ET tubes. We collected eight ET tubes with intubation periods between 12 h and 23 d from different patients in a surgical and a medical intensive care unit. Our qPCR data showed that ET tubes were colonized within 24 h. However, the variation between patients was too high to find a positive correlation between the bacterial load and intubation period. We obtained 1263 near full-length 16S rRNA gene sequences from the diverse bacterial communities. Over 70% of these sequences were associated with genera of typical oral flora, while only 6% were associated with gastrointestinal flora. The most common genus identified was Streptococcus (348/1263), followed by Prevotella (179/1263), and Neisseria (143/1263) with the highest relative concentrations for ET tubes with short intubation periods, indicating oral inoculation of the ET tubes. Our study also shows that even though potentially pathogenic bacteria existed in ET tube biofilms within 24 h of intubation, a longer intubation period increases the opportunity for these organisms to proliferate. In the ET tube that was in place for 23 d, 95% of the sequences belonged to Pseudomonas aeruginosa, which is a bacterial pathogen that is known to out compete commensal bacteria in biofilms, especially during periods of antibiotic treatment. Harboring such pathogens in ET biofilms may increase the chance of VAP, and should be aggressively monitored and prevented.

Strategies to prevent ventilator-associated pneumonia in acute care hospitals

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections. The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their ventilator-associated pneumonia (VAP) prevention efforts. Refer to the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America “Compendium of Strategies to Prevent Healthcare-Associated Infections” Executive Summary and Introduction and accompanying editorial for additional discussion.

1. Occurrence of VAP in acute care facilities.

a. VAP is one of the most common infections acquired by adults and children in intensive care units (ICUs).

i. In early studies, it was reported that 10%-20% of patients undergoing ventilation developed VAP. More-recent publications report rates of VAP that range from 1 to 4 cases per 1,000 ventilator-days, but rates may exceed 10 cases per 1,000 ventilator-days in some neonatal and surgical patient populations. The results of recent quality improvement initiatives, however, suggest that many cases of VAP might be prevented by careful attention to the process of care.

2. Outcomes associated with VAP

a. VAP is a cause of significant patient morbidity and mortality, increased utilization of healthcare resources, and excess cost.

i. The mortality attributable to VAP may exceed 10%.

ii. Patients with VAP require prolonged periods of mechanical ventilation, extended hospitalizations, excess use of antimicrobial medications, and increased direct medical costs.

Antimicrobial-coated endotracheal tubes: an experimental study

OBJECTIVE

Antibiotic-resistant bacterial biofilm may quickly form on endotracheal tubes (ETTs) and can enter the lungs, potentially causing pneumonia. In an attempt to prevent bacterial colonization, we developed and tested in an in-vitro study and animal study several antibacterial-coated ETTs (silver sulfadiazine with and without carbon in polyurethane, silver sulfadiazine and chlorhexidine with and without carbon in polyurethane, silver-platinum with and without carbon in polyurethane, chlorhexidine in polyurethane, and rose bengal for UV light). DESIGN, SETTING, ANIMALS, INTERVENTIONS: After preliminary studies, silver sulfadiazine in polyurethane (SSD-ETT) was selected among the coatings to be challenged every 24 h with 10(4)-10(6) Pseudomonas aeruginosa/ml and evaluated at 6 h, 24 h, and 72 h with standard microbiological studies, scanning electron microscopy, and confocal scanning microscopy. Subsequently, eight sheep were randomized to receive either a SSD-ETT or a standard ETT (St-ETT). After 24 h of mechanical ventilation, standard microbiological studies were performed together with scanning electron microscopy and confocal microscopy.

MEASUREMENTS AND RESULTS

In the in-vitro study SSD-ETT remained bacteria-free for up to 72 h, whereas St-ETT showed heavy P. aeruginosa growth and biofilm formation (p < 0.01). In sheep, the SSD-ETT group showed no bacterial growth in the ETT, ventilator tubing, and lower respiratory tract, while heavy colonization was found in the St-ETT (p < 0.01), ventilator tubing (p=0.03), and lower respiratory tract (p < 0.01).

CONCLUSION

This study describes several effective and durable antibacterial coatings for ETTs. Particularly, SSD-ETT showed prevention against P. aeruginosa biofilm formation in a 72-h in-vitro study and lower respiratory tract colonization in sheep mechanically ventilated for 24 h.

A new method for chlorhexidine (CHX) determination: CHX release after application of differently concentrated CHX-containing preparations on artificial fissures

Aims of the study were (1) to establish a method for quantification of chlorhexidine (CHX) in small volumes and (2) to determine CHX release from differently concentrated CHX-containing preparations, varnishes, and a CHX gel applied on artificial fissures. CHX determination was conducted in a microplate reader using polystyrene wells. The reduced intensity of fluorescence of the microplates was used for CHX quantification. For verification of the technique, intra- and inter-assay coefficients of variation were calculated for graded series of CHX concentrations, and the lower limit of quantification (LLOQ) was determined. Additionally, artificial fissures were prepared in 50 bovine enamel samples, divided into five groups (A-E, n=10) and stored in distilled water (7 days); A: CHX-varnish EC40; B: CHX-varnish Cervitec; C: CHX-gel Chlorhexamed; D: negative control, no CHX application; and E: CXH-diacetate standard (E1, n=5) or CHX-digluconate (E2, n=5) in the solution. The specimens were brushed daily, and CHX in the solution was measured. The method showed intra- and inter-assay coefficients of variation of <10 and <20%, respectively; LLOQ was 0.91-1.22 nmol/well. The cumulative CHX release (mean+/-SD) during the 7 days was: EC40 (217.2+/-41.8 nmol), CHX-gel (31.3+/-8.5 nmol), Cervitec (18.6+/-1.7 nmol). Groups A-C revealed a significantly higher CHX release than group D and a continuous CHX-release with the highest increase from day 0 to 7 for EC40 and the lowest for Chlorhexamed. The new method is a reliable tool to quantify CHX in small volumes. Both tested varnishes demonstrate prolonged and higher CHX release from artificial fissures than the CHX-gel tested.

Tracheostomy inner cannula care: a randomized crossover study of two decontamination procedures

BACKGROUND

Today several methods for decontaminating inner cannulae exist. These methods are not based on scientific data, but often on local clinical tradition. This study compares two different decontamination methods. The aim was to find a practical and safe decontamination method. It is a randomized, single-blinded, comparative crossover study.

METHODS

Fifty outpatients with long-term tracheostomy with an inner cannula were consecutively included and randomly allocated to begin with one of two different treatment sequences: detergent and chlorhexidine-alcohol (A) or detergent (B). Samples for bacterial culture were taken before and after decontamination, and the number of bacteria colonies was counted.

RESULTS

Before decontamination, the inner cannulae grew high numbers of bacteria, which were parts of the normal flora of the upper respiratory tract and did not differ significantly between the two sequences (AB; BA). The primary variable was the culture count value after chlorhexidine-alcohol/detergent (A) and detergent (B). The effects of both methods were larger than expected, and the results showed a nearly total elimination of organisms. The equivalence criterion, ratio of mean colony counts (A/B) >0.8, was met at a significance level of P<0.001.

CONCLUSIONS

Cleaning the tracheostomy inner cannula with detergent and water is sufficient to achieve decontamination.

In vitro analysis of a nanocrystalline silver-coated surgical mesh

BACKGROUND AND PURPOSE

One million nosocomial infections occur each year in patients with prosthetic devices. We analyzed a polypropylene mesh coated with nanocrystalline silver particles (NCSP) as a means of preventing such infections.

METHODS

Nanocrystalline silver was applied to polypropylene mesh using physical vapor deposition in three doses: low (0.31 mg/cm(2)), medium (0.64 mg/cm(2)), and high (1.13 mg/cm(2)). The zone of inhibition (ZOI) test was conducted by incubating either uncoated polypropylene mesh (UM) or silver-coated mesh (CM) with and without various amounts of bovine serum albumin (BSA) and then on agar plates with Staphylococcus aureus and calculating the ZOI. The bactericidal effects of the NCSP-coated meshes were assessed by incubating either UM or CM in medium with S. aureus and performing serial dilutions at 4 and 8 h. Scanning electron microscopy (SEM) was used to examine the surface of UM and CM with and without bacterial incubation.

RESULTS

There was an increasing ZOI for low-, medium-, and high-dose CM and no ZOI for UM (p < 0.001 for all CM compared with UM). Incubating the mesh with various amounts of BSA produced persistent ZOIs with the medium- and high-dose CM; however, the low-dose CM became attenuated by such treatment, with no ZOI being seen with meshes incubated in 10% BSA. All concentrations of CM were bactericidal, as no bacteria grew at 8 h of incubation. The SEM images showed clusters of S. aureus on the surface of UM and no clusters on CM.

CONCLUSIONS

The CM demonstrated significant bactericidal activity compared with UM. Nanocrystalline silver particles may decrease the incidence of postoperative prosthetic mesh infections and be useful as a coating for other prosthetic materials.

Prevention measures for ventilator-associated pneumonia: a new focus on the endotracheal tube

PURPOSE OF REVIEW

The aim of this article is to analyze the aspects related to the endotracheal tube which may influence the development of ventilator-associated pneumonia and to review the possible measures of prevention.

RECENT FINDINGS

The endotracheal tube participates in the pathogenesis of ventilator-associated pneumonia by the elimination of natural defense mechanisms, thereby allowing the entry of bacteria by the aspiration of subglottic secretions or the formation of biofilm on the endotracheal tube. The preventive measures of ventilator-associated pneumonia related to the endotracheal tube include these two mechanisms. It has been suggested that substitution of the endotracheal tube by early tracheostomy may reduce the risk of ventilator-associated pneumonia.

SUMMARY

Aspiration of the subglottic secretions seems to be an effective measure with little risk; decontamination or exhaustive control of the sealing of the cuff has not demonstrated a positive risk/benefit balance. The causal relationship between biofilm and ventilator-associated pneumonia has not been clearly established. Treatment of the biofilm with antibiotics, changes in the composition of the endotracheal tube or mechanical cleansing have achieved a reduction or elimination of the biofilm but their effect on the incidence of ventilator-associated pneumonia has not been studied. The benefit of early tracheostomy in reducing ventilator-associated pneumonia is still controversial.

Antibacterial-coated tracheal tubes cleaned with the Mucus Shaver : a novel method to retain long-term bactericidal activity of coated tracheal tubes

OBJECTIVE

To assess the long-term benefit from antibacterial coatings of the tracheal tube (ETT), and to keep clean the lumen of the ETT.

DESIGN

Experimental animal study.

SETTING

USA National Institutes of Health.

SUBJECTS

Twelve sheep.

INTERVENTIONS

Twelve ETTs were internally dip-coated with a silver-sulfadiazine in polyurethane. We developed a concentric inflatable silicone rubber "razor", the Mucus Shaver (MS), to shave the ETT lumen free of mucus. In a single pass, we cleaned all mucus from the internal surface of the ETT.

CONTROL GROUP

Five intubated sheep were mechanically ventilated for 72 h. The ETT was suctioned every 6 h.

STUDY GROUP

Six sheep were intubated and mechanically ventilated for 72 h. The ETT was suctioned and cleaned with the MS every 6 h. An additional sheep was intubated and mechanically ventilated for 168 h. Bacteriologic studies and scanning electron microscopy were performed to assess bacterial colonization and thickness of secretions on the internal surface of the ETT.

MEASUREMENTS AND MAIN RESULTS

In the control group, the ETT was always heavily colonized: median debris thickness was 380 microm, range 270-550 microm. In the study group, there was no colonization and no secretions in the ETT, except for three ETT that were colonized solely at the very tip.

CONCLUSIONS

Silver-based coating of ETT cleaned with the MS every 6 h significantly reduces accumulation of mucus/secretion and bacterial growth within the ETT following 72 h of mechanical ventilation.