Respiratory pathogen colonization of dental plaque, the lower airways, and endotracheal tube biofilms during mechanical ventilation

Development and validation of a nomogram for oral mucosal membrane pressure injuries in ICU patients: A prospective cohort study

AIMS

Establishing a nomogram to estimate the probability of oral mucosal membrane pressure injury of endotracheal tube-intubated hospitalized patients in intensive care unit.

DESIGN

Multicentre prospective cohort study.

METHODS

Using Lasso regression and COX regression, variable selection was performed on demographic, clinical and laboratory data of 1037 ICU endotracheal tube-intubated hospitalized patients from West China Hospital, to construct a nomogram. External validation was conducted on 484 ICU endotracheal tube-intubated patients from People's Hospital of Zhongjiang County.

RESULTS

Among 38 potential predictors, five variables emerged as independent predictors, integrated into the nomogram: administration of antibiotics, nutritional therapy duration, agitation, hypotension and albumin levels.

CONCLUSIONS

We established a nomogram based on the hospital characteristics of ICU endotracheal tube-intubated patients, aiding in the prediction of the occurrence of oral mucosal membrane pressure injury.

REPORTING METHOD

The study followed TRIPOD guidelines.

RELEVANCE TO CLINICAL PRACTICE

The nomogram we developed can assist clinical worker in better identifying at-risk patients and risk factors. It enables the implementation of evidence-based nursing interventions in care to prevent the development of oral mucosal membrane pressure injury.

TRIAL REGISTRATION

The study has been registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn) under registration number ChiCTR2200056615.

Evaluation of brushing efficiency in reducing oral microbiota in mechanically ventilated patients admitted to an intensive care unit

Background

Patients admitted to the Intensive Care Unit (ICU) are at greater risk of developing nosocomial infections due to their investigations, treatment and changes in the immune system. One of the most prevalent nosocomial infections is respiratory tract infection, such as hospital acquired pneumonia and ventilator-associated pneumonia (VAP). The bacteria commonly found in the oral cavity in the hospital environment are Streptococcus viridians, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus spp., and Klebsiella pneumoniae. There is a need to test and define appropriate standard protocols for oral hygiene in patients undergoing mechanical ventilation in ICUs through the intervention of a dental specialist, preventing the proliferation of microorganisms into the respiratory tract, thus reducing hospitalization time, the use of antibiotics, and increased morbidity/mortality. Objective: This study aimed to evaluate the effectiveness of dental brushing in the reduction of the pathogenic buccal microbiota associated with mechanical ventilation in patients admitted to the Evangelical Hospital from Londrina, Paraná, Brazil.

Methodology

The sample consisted of 90 patients (of both sexes), mean age of 65 years, under mechanical ventilation by orotracheal tube and tracheostomized patients, without suspected or confirmed diagnosis of pneumonia. Patients were randomized ∗∗∗.

Results

Results showed that oral hygiene using a toothbrush by suction, with chlorhexidine gel 0.12% (Group B), was more effective than conventional hygiene using gauze soaked with chlorhexidine 0.12% (Group A) in reducing pathogenic buccal microbiota.

Conclusions

There was a reduction of the pathogenic buccal microbiota in mechanically ventilated patients receiving oral hygiene using a toothbrush by suction with chlorhexidine gel 0.12% (Group B).

Constructing a Nomogram Model to Estimate the Risk of Ventilator-Associated Pneumonia for Elderly Patients in the Intensive Care Unit

BACKGROUND

Ventilator-associated pneumonia (VAP) causes heavy losses in terms of finances, hospitalization, and death for elderly patients in the intensive care unit (ICU); however, the risk is difficult to evaluate due to a lack of reliable assessment tools. We aimed to create and validate a nomogram to estimate VAP risk to provide early intervention for high-risk patients.

METHODS

Between January 2016 and March 2021, 293 patients from a tertiary hospital in China were retrospectively reviewed as a training set. Another 84 patients were enrolled for model validation from April 2021 to February 2022. Least absolute shrinkage and selection operator (LASSO) regression and multivariable logistic regression analysis were employed to select predictors, and a nomogram model was constructed. The calibration, discrimination, and clinical utility of the nomogram were verified. Finally, a web-based online scoring system was created to make the model more practical.

RESULTS

The predictors were hypoproteinemia, long-term combined antibiotic use, intubation time, length of mechanical ventilation, and tracheotomy/intubation. The area under the curve (AUC) was 0.937 and 0.925 in the training and validation dataset, respectively, suggesting the model exhibited effective discrimination. The calibration curve demonstrated high consistency with the observed result and the estimated values. Decision curve analysis (DCA) demonstrated that the nomogram was clinically applicable.

CONCLUSIONS

We have created a novel nomogram model that can be utilized to anticipate VAP risk in elderly ICU patients, which is helpful for healthcare professionals to detect patients at high risk early and adopt protective interventions.

Quantitative oral health assessments in mechanically ventilated patients: A scoping review

BACKGROUND

Oral health is a key contributor to a person's overall health. Previous studies indicate that oral health deteriorates throughout ventilation and may contribute to the development of ventilator-associated pneumonia (VAP). Oral health at the time of initial ventilation may impact on this deterioration.

AIMS

To determine the quantitative clinical assessment methods used to measure oral health and what is currently known regarding the oral health of patients at the time of initial ventilation.

STUDY DESIGN

A systematic literature search using electronic bibliographic databases MEDLINE/PubMed, Embase, CINAHL, and the Cochrane Library was undertaken for this scoping review. Studies were included if patients were >18 years old and mechanically ventilated for <48 h at the time of the first oral assessment.

RESULTS

In total, 12 studies were included. The review demonstrates a limited understanding of clinical oral health at the time of initial ventilation. Significant variation in both assessment methods and reporting of oral health makes comparison of results difficult resulting in a poor overall understanding of oral health at the time of intubation.

CONCLUSION

Standardized assessment and reporting methods may improve clinical application of findings and help direct future research. We suggest developing a core outcome set to ensure consistent use of assessment tools as well as standardized reporting of results.

RELEVANCE TO CLINICAL PRACTICE

It is essential that a good understanding of oral health at the time of initial ventilation is gained so that patients receive more targeted oral hygiene intervention in ICU, potentially leading to improved patient outcomes.

Prevalence of oral complications in the course of severe SARS-CoV-2 infection under mechanical non-invasive ventilation

BACKGROUND

The management of oral health during severe symptoms of Covid-19 is still a challenge, especially in intensive care units under invasive/noninvasive ventilation in hospital. Understanding the cause-and-effect relationships may allow for individual adjustment of oral care recommendations during Covid-19 disease. The study's objective was to assess Covid-19 patients' oral health status under hospital treatment due to pulmonary adverse Covid-19 outcomes.

MATERIAL AND METHODS

Covid-19 patients (mean age 74.4 ± 15.4; n = 120, male n = 50/female n = 70) were admitted to hospital in the acute phase of Covid-19 between January and March 2022 who required oxygen therapy due to pneumonia, rapid respiratory failure, low saturation. Blood and radiological tests were taken according to National Health Fund guidelines. The condition of teeth (Decayed, Missing, Filled teeth as DMFT index), dental hygiene (Plaque Control Record as PCR index), periodontal status (probing depth PD, clinical attachment CAL, bleeding on probing BOP) and oral mucosa (BRUSHED and Beck scores) were examined.

RESULTS

Charateristics of the teeth (dental caries 35.2%, DMFT Median 22), plaque retention (83.4%), advanced periodontitis (48.3%), xerostomia (74.2%), oral mucosa inflammation (80.8%), angular cheilitis (53.3%), hemorrhagic (21.7%) showed a high incidence of harmful oral conditions. BRUSHED model and Beck score indicated moderate oral dysfunction and need for oral care every 8 h. Spearman's analysis revealed a significant positive correlation between pneumonia and neutrophile, interleukin-6 IL-6, C-reactive protein CRP (p = 0.01, p < 0.001, p < 0.001), negative to lymphocyte count (p < 0.001). Multiple and logistic regressions selected the following risk predictors for pneumonia as IL-6, CRP, obesity and for severe COVID-19 symptoms D-dimer level and a lack of targeted vaccination (p < 0.001). Among oral predictors, the PCR index and Beck score were significant for both outcomes (respectively p < 0.001, p < 0.012). Patients who received oxygen therapy with face masks had more often angular heilitis and debris (p = 0.025, p = 0.035).

CONCLUSIONS

COVID-19 hospitalised patients with severe symptoms crossing with poor oral health-related conditions. This may exacerbate a response for COVID infection, and play a role in cytokine storm. For Covid-19 management, to inhibit extraoral/intraoral complications, it is recommended to adjust oral hygiene procedures, including antibacterial, protective, moisturising agents after individual oral health assessment.

Exploring the complex relationship between the lung microbiome and ventilator-associated pneumonia

INTRODUCTION

Understanding the presence and function of a diverse lung microbiome in acute lung infections, particularly ventilator-associated pneumonia (VAP), is still limited, evidencing significant gaps in our knowledge.

AREAS COVERED

In this comprehensive narrative review, we aim to elucidate the contribution of the respiratory microbiome in the development of VAP by examining the current knowledge on the interactions among microorganisms. By exploring these intricate connections, we endeavor to enhance our understanding of the disease's pathophysiology and pave the way for novel ideas and interventions in studying the respiratory tract microbiome.

EXPERT OPINION

The conventional perception of lungs as sterile is deprecated since it is currently recognized the existence of a diverse microbial community within them. However, despite extensive research on the role of the respiratory microbiome in healthy lungs, respiratory chronic diseases and acute lung infections such as pneumonia are not fully understood. It is crucial to investigate further the relationship between the pathophysiology of VAP and the pulmonary microbiome, elucidating the mechanisms underlying the interactions between the microbiome, host immune response and mechanical ventilation for the development of VAP.

Poor Oral Health in the Etiology and Prevention of Aspiration Pneumonia

Aspiration pneumonia (AP), inflammation of the lung parenchyma initiated by aspirated microorganisms into the lower airways from proximal sites, including the oral cavity, is prevalent in, and problematic for, the elderly, especially those in institutions, and for those with several important risk factors. Many factors influence the pathogenesis of AP, including dysphagia, poor oral hygiene, diminished host defense, and underlying medical conditions. This article reviews the epidemiology, microbiology, pathogenesis, and prevention of AP, focusing on the role of poor oral health as a risk factor for, and on dental care for the prevention and management of, this important infection.

Formation of a biofilm matrix network shapes polymicrobial interactions

Staphylococcus aureus colonizes the same ecological niche as many commensals. However, little is known about how such commensals modulate staphylococcal fitness and persistence. Here we report a new mechanism that mediates dynamic interactions between a commensal streptococcus and S. aureus. Commensal Streptococcus parasanguinis significantly increased the staphylococcal biofilm formation in vitro and enhanced its colonization in vivo. A streptococcal biofilm-associated protein BapA1, not fimbriae-associated protein Fap1, is essential for dual-species biofilm formation. On the other side, three staphylococcal virulence determinants responsible for the BapA1-dependent dual-species biofilm formation were identified by screening a staphylococcal transposon mutant library. The corresponding staphylococcal mutants lacked binding to recombinant BapA1 (rBapA1) due to lower amounts of eDNA in their culture supernatants and were defective in biofilm formation with streptococcus. The rBapA1 selectively colocalized with eDNA within the dual-species biofilm and bound to eDNA in vitro, highlighting the contributions of the biofilm matrix formed between streptococcal BapA1 and staphylococcal eDNA to dual-species biofilm formation. These findings have revealed an additional new mechanism through which an interspecies biofilm matrix network mediates polymicrobial interactions.

Construction and Validation of a Predictive Model for the Risk of Ventilator-Associated Pneumonia in Elderly ICU Patients

Background

Ventilator-associated pneumonia (VAP) is among the most important hospital-acquired infections in an intensive-care unit setting. However, clinical practice lacks effective theoretical tools for preventing VAP in the elderly.

Aim

To describe the independent factors associated with VAP in elderly intensive-care unit (ICU) patients on mechanical ventilation (MV) and to construct a risk prediction model.

Methods

A total of 1851 elderly patients with MV in ICUs from January 2015 to September 2019 were selected from 12 tertiary hospitals. Study subjects were divided into a model group (n = 1219) and a validation group (n = 632). Two groups of patients were divided into a VAP group and a non-VAP group and compared. Univariate and logistic regression analyses were used to explore influencing factors for VAP in elderly ICU patients with MV, establish a risk prediction model, and draw a nomogram. We used the area under the receiver operating characteristic curve (AUROC) and the Hosmer-Lemeshow goodness-of-fit test to evaluate the predictive effect of the model. Findings regarding the length of ICU stay, surgery, C-reactive protein (CRP), and the number of reintubations were independent risk factors for VAP in elderly ICU patients with MV. Predictive-model verification results showed that the area under the curve (AUC) of VAP risk after MV in the modeling and verification groups was 0.859 and 0.813 (P < 0.001), respectively, while P values for the Hosmer-Lemeshow test in these two groups were 0.365 and 0.485, respectively.

Conclusion

The model could effectively predict the occurrence of VAP in elderly patients with MV in ICUs. This study is a retrospective study, so it has not been registered as a clinical study.

Impact of a dental care intervention on the hospital mortality of critically ill patients admitted to intensive care units: A quasi-experimental study

BACKGROUND

We aimed to evaluate the impact of providing dental care to critically ill patients on their risk of death and ventilator-associated pneumonia (VAP).

METHODS

A quasi-experimental study was conducted in 2 intensive care units (ICU) from 2016 to 2019. The intervention consisted of implementing routine dental care, focusing on oral hygiene and periodontal treatment, at least 3 times a week, for patients admitted to the study units. In the pre-intervention period, routine oral hygiene was provided by the ICU nursing staff. The primary and secondary study outcomes were mortality, evaluated at the end of the ICU stay, and VAP incidence density, respectively. Data were analyzed using the ARIMA (autoregressive integrated moving average) time series model in R software.

RESULTS

During the intervention period, 5,147 dental procedures were performed among 355 patients. The time series showed that ICU mortality was 36.11%, 32.71%, and 32.30% within the 3 years before the intervention, and 28.71% during the intervention period (P = .015). VAP incidence density did not significantly change during the study period (P = .716).

CONCLUSION

A dental care intervention focused on oral hygiene and periodontal treatment regularly provided by dentists to critically ill patients may decrease their risk of dying in the ICU. Randomized clinical trials should be performed to confirm these findings.

TRIAL REGISTRATION

WHO-affiliated Brazilian Clinical Trials Registry. RBR-4jmz36. Registered 7 October 2018, before first patient enrollment.

The Impact of Improved Oral Care Methods on the Oral Health of Patients Undergoing Transoral Mechanical Ventilation

Objective

To explore the effects of improved oral care on the number of oropharyngeal bacteria and the incidence of ventilator-associated pneumonia in patients undergoing mechanical ventilation through oral endotracheal intubation by improving conventional oral care methods and operating procedures and to evaluate the quality of improved oral care and effect.

Methods

A total of 100 cases of mechanically ventilated patients with oral endotracheal intubation who met the inclusion criteria were randomly divided into the observation group and control group with 50 cases each. The control group took routine oral care, that is, scrubbing 3 times per day, and the oral care solution was selected as physiological brine. The observation group improved the conventional oral care method, namely, oral scrubbing before intubation, brushing and washing after intubation, 3 times per day, and 0.1% povidone-iodine in oral care solution. Analysis and comparison of the oral bacterial flora, oral cleanliness, and incidence of ventilator-associated pneumonia, mechanical ventilation time, ICU hospitalization time, and mortality rate of the two groups of patients were analyzed and compared. The relevant data were collected and processed for statistical processing.

Results

The oral bacterial flora of the two groups of patients before oral care after mechanical ventilation after oral tracheal intubation was compared, and there was no significant statistical difference (P > 0.05). After nursing, the oral bacterial flora of the observation group at 8 h, 16 h, and 24 h after intubation was significantly lower than that of the control group. Statistics showed that the difference was statistically significant (P < 0.05). After nursing, the number of patients with oral cleanliness in the observation group was significantly higher than that of the control group, while the incidence of ventilator-associated pneumonia in the observation group was 8% significantly lower than that of the control group 14%. Statistics show that this difference is statistically significant (P < 0.05). After nursing, the observation group's oral cleanliness score, mechanical ventilation time, ICU hospitalization time, and GCS score were better than those of the control group. Statistics showed that the difference was statistically significant (P < 0.05). The mortality of the observation group was significantly lower than that of the control group, which was not statistically significant (P > 0.05).

Conclusion

Oral care can effectively reduce the number of oropharyngeal bacteria in patients who are mechanically ventilated through orotracheal intubation and significantly reduce the incidence of ventilator-associated pneumonia.

Endotracheal tube microbiome in hospitalized patients defined largely by hospital environment

Background

Studies of the respiratory tract microbiome primarily focus on airway and lung microbial diversity, but it is still unclear how these microbial communities may be affected by intubation and long periods in intensive care units (ICU), an aspect that today could aid in the understanding of COVID19 progression and disease severity. This study aimed to explore and characterize the endotracheal tube (ETT) microbiome by analyzing ETT-associated microbial communities.

Methods

This descriptive study was carried out on adult patients subjected to invasive mechanical ventilation from 2 to 21 days. ETT samples were obtained from 115 patients from ICU units in two hospitals. Bacteria isolated from endotracheal tubes belonging to the ESKAPE group were analyzed for biofilm formation using crystal violet quantification. Microbial profiles were obtained using Illumina sequencing of 16S rRNA gene.

Results

The ETT microbiome was mainly composed by the phyla Proteobacteria, Firmicutes and Bacteroidetes. Microbiome composition correlated with the ICU in which patients were hospitalized, while intubation time and diagnosis of ventilator-associated pneumonia (VAP) did not show any significant association.

Conclusion

These results suggest that the ICU environment, or medical practices, could be a key to microbial colonization and have a direct influence on the ETT microbiomes of patients that require mechanical ventilation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02086-7.

Incidence of Postoperative Pneumonia and Oral Microbiome for Patients with Cancer Operation

Postoperative pneumonia is a serious problem for patients and medical staff. In Japan, many hospitals introduced perioperative oral care management for the efficient use of medical resources. However, a high percentage of postoperative pneumonia still developed. Therefore, there is a need to identify the specific respiratory pathogens to predict the incidence of pneumonia The purpose of this study was to find out the candidate of bacterial species for the postoperative pneumonia. This study applied case-control study design for the patients who had a cancer operation with or without postoperative pneumonia. A total of 10 patients undergoing a cancer operation under general anesthesia participated in this study. The day before a cancer operation, preoperative oral care management was applied. Using the next generation sequence, oral microbiome of these patients was analyzed at the time of their first visit, the day before and after a cancer operation. Porphyromonas gingivalis and Fusobacterium nucleatum group can be a high risk at first visit. Atopobium parvulum and Enterococcus faecalis before a cancer operation can be a high risk. Poor oral hygiene increased the risk of incidence of postoperative pneumonia. Increased periodontal pathogens can be a high risk of the incidence of postoperative pneumonia. In addition, increased intestinal bacteria after oral care management can also be a high risk for the incidence of postoperative pneumonia.

Pseudomonas aeruginosa Pneumonia: Evolution of Antimicrobial Resistance and Implications for Therapy

Pseudomonas aeruginosa (PA), a non-lactose-fermenting gram-negative bacillus, is a common cause of nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia (VAP), and infections of urinary tract, intra-abdominal, wounds, skin/soft tissue, and bloodstream. PA rarely affects healthy individuals, but may cause serious infections in patients with chronic structural lung disease, comorbidities, advanced age, impaired immune defenses, or with medical devices (e.g., urinary or intravascular catheters, foreign bodies). Treatment of pseudomonal infections is difficult, as PA is intrinsically resistant to multiple antimicrobials, and may acquire new resistance determinants even while on antimicrobial therapy. Mortality associated with pseudomonal VAP or bacteremias is high (> 35%) and optimal therapy is controversial. Over the past three decades, antimicrobial resistance (AMR) among PA has escalated globally, via dissemination of several international multidrug resistant "epidemic" clones. We discuss the importance of PA as a cause of pneumonia including health care-associated pneumonia, hospital-acquired pneumonia, VAP, the emergence of AMR to this pathogen, and approaches to therapy (both empirical and definitive).

Oral health care for the critically ill: a narrative review

Background

The link between oral bacteria and respiratory infections is well documented. Dental plaque has the potential to be colonized by respiratory pathogens and this, together with microaspiration of oral bacteria, can lead to pneumonia particularly in the elderly and critically ill. The provision of adequate oral care is therefore essential for the maintenance of good oral health and the prevention of respiratory complications.

Main body

Numerous oral care practices are utilised for intubated patients, with a clear lack of consensus on the best approach for oral care. This narrative review aims to explore the oral-lung connection and discuss in detail current oral care practices to identify shortcomings and offer suggestions for future research. The importance of adequate oral care has been recognised in guideline interventions for the prevention of pneumonia, but practices differ and controversy exists particularly regarding the use of chlorhexidine. The oral health assessment is also an important but often overlooked element of oral care that needs to be considered. Oral care plans should ideally be implemented on the basis of an individual oral health assessment. An oral health assessment prior to provision of oral care should identify patient needs and facilitate targeted oral care interventions.

Conclusion

Oral health is an important consideration in the management of the critically ill. Studies have suggested benefit in the reduction of respiratory complication such as Ventilator Associated Pneumonia associated with effective oral health care practices. However, at present there is no consensus as to the best way of providing optimal oral health care in the critically ill. Further research is needed to standardise oral health assessment and care practices to enable development of evidenced based personalised oral care for the critically ill.

What is the future of Periodontal Medicine?

In the last five decades, considerable progress has been made towards understanding the etiology and pathogenesis of periodontal diseases and their interactions with the host. The impact of an individual periodontal condition on systemic homeostasis became more evident because of this knowledge and prompted advances in studies that associate periodontitis with systemic diseases and conditions. The term Periodontal Medicine describes how periodontal infection/inflammation can affect extraoral health. This review presents the current scientific evidence on the most investigated associations between periodontitis and systemic diseases and conditions, such as cardiovascular diseases, diabetes, preterm birth and low birth weight, and pneumonia. Additionally, other associations between periodontitis and chronic inflammatory bowel disease, colorectal cancer, and Alzheimer's disease that were recently published and are still poorly studied were described. Thus, the aim of this review was to answer the following question: What is the future of Periodontal Medicine? Epidemiological evidence and the evidence of biological plausibility between periodontitis and general health reinforce the rationale that the study of Periodontal Medicine should continue to advance, along with improvements in the epidemiological method, highlighting the statistical power of the studies, the method for data analysis, the case definition of periodontitis, and the type of periodontal therapy to be applied in intervention studies.

Microbiome in Critical illness: An Unconventional and Unknown Ally

BACKGROUND

The digestive tract represents an interface between the external environment and the body where the interaction of a complex polymicrobial ecology has an important influence on health and disease. The physiological mechanisms that are altered during the hospitalization and in the intensive care unit (ICU) contribute to the pathobiota's growth. Intestinal dysbiosis occurs within hours of being admitted to ICU. This may be due to different factors, such as alterations of normal intestinal transit, administration of variuos medications or alterations in the intestinal wall which causes a cascade of events that will lead to the increase of nitrates and decrease of oxygen concentration, liberation of free radicals.

OBJECTIVE

This work aims to report the latest updates on the microbiota's contribution to developing sepsis in patients in the ICU department. In this short review were reviewed the latest scientific findings on the mechanisms of intestinal immune defenses performed both locally and systemically. In addition, we considered it necessary to review the literature to report the current best treatment strategies to prevent the infection spread which can bring systemic infections in patients admitted to ICU.

MATERIAL AND METHODS

This review has been written to answer at three main questions: what are the main intestinal flora's defense mechanisms that help us to prevent the risk of developing systemic diseases on a day-to-day basis? What are the main dysbiosis' systemic abnormalities? What are the modern strategies that are used in the ICU patients to prevent the infection spread? Using the combination of following keywords: microbiota and ICU, ICU and gut, microbiota and critical illness, microbiota and critical care, microbiota and sepsis, microbiota and infection, gastrointestinal immunity,in the Cochrane Controlled Trials Register, the Cochrane Library, medline and pubmed, google scholar, ovid/wiley. Finally, we reviewed and selected 72 articles. We also consulted the site ClinicalTrials.com to find out studies that are recently conducted or ongoing.

RESULTS

The critical illness can alter intestinal bacterial flora leading to homeostasis disequilibrium. Despite numerous mechanisms, such as epithelial cells with calciform cells that together build a mechanical barrier for pathogenic bacteria, the presence of mucous associated lymphoid tissue (MALT) which stimulates an immune response through the production of interferon-gamma (IFN-y) and THN-a or by stimulating lymphocytes T helper-2 produces anti-inflammatory cytokines. But these defenses can be altered following a hospitalization in ICU and lead to serious complications such as acute respiratory distress syndrome (ARDS), health care associated pneumonia (HAP) and ventilator associated pneumonia (VAP), Systemic infection and multiple organ failure (MOF), but also in the development of coronary artery disease (CAD). In addition, the microbiota has a significant impact on the development of intestinal complications and the severity of the SARS-COVID-19 patients.

CONCLUSION

The microbiota is recognized as one of the important factors that can worsen the clinical conditions of patients who are already very frailty in intensive care unit. At the same time, the microbiota also plays a crucial role in the prevention of ICU associated complications. By using the resources, we have available, such as probiotics, symbiotics or fecal microbiota transplantation (FMT), we can preserve the integrity of the microbiota and the GUT, which will later help maintain homeostasis in ICU patients.

Probiotic Bacterial Application in Pediatric Critical Illness as Coadjuvants of Therapy

The use of probiotics in critically ill adult and children patients has been growing exponentially over the last 20 years. Numerous factors in pediatriac intensive care unit (PICU) patients may contribute to intestinal dysbiosis, which subsequently promotes the pathobiota's growth. Currently, lactobacillus and bifidobacterium species are mainly used to prevent the development of systemic diseases due to the subverted microbiome, followed by streptococcus, enterococcus, propionibacterium, bacillus and Escherichia coli, Lactobacillus rhamnosus GG, and Lactobacillus reuteri DSM 17938. The aim of this article is to review the scientific literature for further confirmation of the importance of the usage of probiotics in intensive care unit (ICU) patients, especially in the pediatric population. A progressive increase in nosocomial infections, especially nosocomial bloodstream infections, has been observed over the last 30 years. The World Health Organization (WHO) reported that the incidence of nosocomial infections in PICUs was still high and ranged between 5% and 10%. Petrof et al. was one of the first to demonstrate the efficacy of probiotics for preventing systemic diseases in ICU patients. Recently, however, the use of probiotics with different lactobacillus spp. has been shown to cause a decrease of pro-inflammatory cytokines and an increase in anti-inflammatory cytokines. In addition, in some studies, the use of probiotics, in particular the mix of Lactobacillus and Bifidobacterium reduces the incidence of ventilator-associated pneumonia (VAP) in PICU patients requiring mechanical ventilation. In abdominal infections, there is no doubt at all about the usefulness of using Lactobacillus spp probiotics, which help to treat ICU-acquired diarrhoea episodes as well as in positive blood culture for candida spp. Despite the importance of using probiotics being supported by various studies, their use is not yet part of the standard protocols to which all doctors must adhere. In the meantime, while waiting for protocols to be drawn up as soon as possible for use in PICUs, routine use could certainly stimulate the intestine's immune defences. Though it is still too early to say, they could be considered the drugs of the future.

Oral and tracheal microbiota of pediatric and adolescent patients in an intensive care unit

OBJECTIVE

To characterize the oral and tracheal microbiota of patients admitted to a pediatric intensive care unit (PICU).

METHODS AND RESULTS

This is an exploratory study conducted on patients aged 5 months to 13 years admitted to the PICU of a referral hospital. Two microbiological samples were collected with a swab in the posterior region of the tongue from patients receiving spontaneous and mechanical ventilation within the first 24 and 48 h after admission to the PICU. Among patients receiving mechanical ventilation, tracheal secretion was also collected in a second sampling. The caries experience was evaluated using the DMFT/dmf index, and the quality of oral hygiene was assessed based on the visual plaque index (VPI). A questionnaire was applied to obtain data on hospital routine and sample characteristics. The DMFT/dmf index was 1.66 (SD = 2.18) and the mean VPI was 43.03 (SD = 36.93). The most prevalent microorganisms were Klebsiella pneumoniae (15%). Oral colonization by opportunistic pathogens was significantly higher in patients receiving mechanical ventilation compared to those on spontaneous ventilation (p < .05). There was no relationship of VPI or DMFT/dmf with oral microbiological changes.

CONCLUSION

The results indicate that PICU patients are susceptible to colonization by respiratory and opportunistic pathogens since the first hours of hospitalization.

Oral Pathogen Fusobacterium nucleatum Coaggregates With Pseudomonas aeruginosa to Modulate the Inflammatory Cytotoxicity of Pulmonary Epithelial Cells

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality worldwide, and inflammatory damage induced by bacterial infections is an important contributor to the etiology of COPD. Fusobacterium nucleatum, a recognized periodontal pathogen, is considered as a biomarker of lung function deterioration of COPD patients coinfected with Pseudomonas aerugionsa, but the underlying mechanism is still unclear. This study established single- and dual-species infection models, bacterial simultaneous and sequential infection models, and found that F. nucleatum could coaggregate with P. aeruginosa to synergistically invade into pulmonary epithelial cells and transiently resist P. aeruginosa-induced cytotoxic damage to amplify IL-6 and TNF-α associated inflammation in pulmonary epithelial cells simultaneously infected with P. aeruginosa and F. nucleatum. Furthermore, F. nucleatum pretreatment or subsequential infection could maintain or even aggravate P. aeruginosa-induced inflammatory cytotoxicity of pulmonary epithelial cells. These results indicate that oral pathogen F. nucleatum coaggregates with P. aeruginosa to facilitate bacterial invasion and modulates the inflammatory cytotoxicity of pulmonary epithelial cells, which may contribute to lung function deterioration of COPD patients accompanied with P. aeruginosa and F. nucleatum coinfection.

Temporal airway microbiome changes related to ventilator-associated pneumonia in children

We sought to determine whether temporal changes in the lower airway microbiome are associated with ventilator-associated pneumonia (VAP) in children.Using a multicentre prospective study of children aged 31 days to 18 years requiring mechanical ventilation support for >72 h, daily tracheal aspirates were collected and analysed by sequencing of the 16S rRNA gene. VAP was assessed using 2008 Centers for Disease Control and Prevention paediatric criteria. The association between microbial factors and VAP was evaluated using joint longitudinal time-to-event modelling, matched case-control comparisons and unsupervised clustering.Out of 366 eligible subjects, 66 (15%) developed VAP at a median of 5 (interquartile range 3-5) days post intubation. At intubation, there was no difference in total bacterial load (TBL), but Shannon diversity and the relative abundance of Streptococcus, Lactobacillales and Prevotella were lower for VAP subjects versus non-VAP subjects. However, higher TBL on each sequential day was associated with a lower hazard (hazard ratio 0.39, 95% CI 0.23-0.64) for developing VAP, but sequential values of diversity were not associated with VAP. Similar findings were observed from the matched analysis and unsupervised clustering. The most common dominant VAP pathogens included Prevotella species (19%), Pseudomonas aeruginosa (14%) and Streptococcus mitis/pneumoniae (10%). Mycoplasma and Ureaplasma were also identified as dominant organisms in several subjects.In mechanically ventilated children, changes over time in microbial factors were marginally associated with VAP risk, although these changes were not suitable for predicting VAP in individual patients. These findings suggest that focusing exclusively on pathogen burden may not adequately inform VAP diagnosis.

Poor Oral Health in the Etiology and Prevention of Aspiration Pneumonia

Aspiration pneumonia (AP), inflammation of the lung parenchyma initiated by aspirated microorganisms into the lower airways from proximal sites, including the oral cavity, is prevalent in, and problematic for, the elderly, especially those in institutions, and for those with several important risk factors. Many factors influence the pathogenesis of AP, including dysphagia, poor oral hygiene, diminished host defense, and underlying medical conditions. This article reviews the epidemiology, microbiology, pathogenesis, and prevention of AP, focusing on the role of poor oral health as a risk factor for, and on dental care for the prevention and management of, this important infection.

Combination of toothbrushing and chlorhexidine compared with exclusive use of chlorhexidine to reduce the risk of ventilator-associated pneumonia: A systematic review with meta-analysis

This study aimed to compare the effectiveness of 0.12% chlorhexidine alone and 0.12% chlorhexidine in combination with toothbrushing to prevent ventilator-associated pneumonia (VAP) in mechanically ventilated patients. The Embase, Latin American and Caribbean Health Science Literature, PubMed, Scientific Electronic Library Online, Scopus, LIVIVO, Web of Science, Cochrane Library, OpenThesis, and Open Access Thesis and Dissertations databases were used. Only randomized controlled trials without restrictions on the year or language of publication were included. Two reviewers assessed the risk of bias using the Joanna Briggs Institute Critical Appraisal Tool. A meta-analysis using a random-effects model estimated the combined relative risk (RR). The Grading of Recommendations, Assessment, Development and Evaluations approach was used to assess the certainty of the evidence. Initially, 2,337 studies were identified, of which 4 were considered in the systematic review and 3 in the meta-analysis (total sample: 796 patients). The studies were published between 2009 and 2017. All eligible studies had a low risk of bias. The meta-analysis revealed that the risk of VAP was 24% lower in patients receiving chlorhexidine combined with toothbrushing than in those receiving chlorhexidine alone (RR: 0.76; 95% confidence interval: 0.55-1.06), with moderate certainty of evidence and without statistical significance. In conclusion, considering the limitations of this study, a standard protocol for the prevention of VAP is not yet recommended. More studies with larger sample sizes are needed to draw strong conclusions. However, considering that toothbrushing is a simple intervention, it should be a common practice in mechanically ventilated patients, especially among patients with coronavirus disease.

Orale Immunkompetenz in der Corona-Pandemie vs. Systemrelevanz der Zahnmedizin

Die Covid-19-Pandemie hat das deutsche Gesundheitssystem im Jahr 2020 vor erhebliche Herausforderungen gestellt. In diesem Zusammenhang ist es bemerkenswert, dass für die Zahnmedizin kein sogenannter Rettungsschirm aufgespannt wurde. Dies bedeutet, dass nach Ansicht der Bundesregierung Zahnärzte als nicht systemrelevant eingestuft wurden und somit offiziell auch nicht zu den Ärzten gehören. Diese Annahme ist grundfalsch und gefährlich, wie im Folgenden anhand eines wichtigen Beispiels erörtert wird.

Das SARS-CoV-2-Virus führt bei infizierten Personen zu einem Beschwerdebild von leichten Erkältungszeichen bis hin zu lebensbedrohlichen beatmungsbedürftigen COVID-19-Pneumonien. Ein besonderes Risiko für schwere Verläufe haben Menschen höheren Alters sowie Patienten mit Diabetes, Bluthochdruck und anderen schweren Erkrankungen. Die Haupteintrittspforte für das SARS-CoV-2-Virus in den menschlichen Körper ist u. a. die orale Mukosa, denn die Viren reichern sich dort bevorzugt an und der ACE2-Rezeptor wird dort hochgradig exprimiert. Dieser Penetrationsweg erklärt die häufigeren schweren Verläufe bei älteren Diabetespatienten, deren Immunsystem bereits generell beeinträchtigt ist. Diabetes mellitus induziert eine chronische systemische Entzündung, die sich gerade im Mundbereich regelmäßig als Parodontitis manifestiert. Bei Diabetikern zwangsläufig oft auftretende Hyperglykämien schwächen die Mukosa-Barriere zusätzlich. Es ist daher dringend ratsam, bei Präventionsmaßnahmen für Diabetespatienten den Mund- und Rachenraum nicht zu ignorieren. Neben der parodontalprophylaktischen Betreuung ist gerade in Absenz von Zahnärzten die aktivierte Matrix-Metalloproteinase 8 (aMMP8) ein etablierter Biomarker. Die aktuellen Empfehlungen zur Prävention der SARS-CoV-2-assoziierten COVID-19-Erkrankung sollte daher um die Aspekte der Messung und Sanierung des Mund- und Rachenraums sowie einer regelmäßigen Desinfektion der oralen Mukosa erweitert werden.

Reconsidering ventilator-associated pneumonia from a new dimension of the lung microbiome

Complex microbial communities that reside in the lungs, skin and gut are now appreciated for their role in maintaining organ, tissue and immune homoeostasis. As lungs are currently seen as an ecosystem, the shift in paradigm calls for the consideration of new algorithms related to lung ecology in pulmonology. Evidence of lung microbiota does not solely challenge the traditional physiopathology of ventilator-associated pneumonia (VAP); indeed, it also reinforces the need to include molecular techniques in VAP diagnosis and accelerate the use of immunomodulatory drugs, including corticosteroids, and other supplements such as probiotics for VAP prevention and/or treatment. With that stated, both microbiome and virome, including phageome, can lead to new opportunities in further understanding the relationship between health and dysbiosis in VAP. Previous knowledge may be, however, reconsidered at a microbiome scale.

Fusobacterium nucleatum Interaction with Pseudomonas aeruginosa Induces Biofilm-Associated Antibiotic Tolerance via Fusobacterium Adhesin A

Respiratory infections with Pseudomonas aeruginosa or Fusobacterium nucleatum are associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and failure in antibiotic treatment. However, the impact of these dual-species interactions on the severity of chronic obstructive pulmonary disease (COPD) and biofilm antibiotic susceptibility remains poorly understood. This study demonstrated that F. nucleatum frequently coexisted with P. aeruginosa in the respiratory tract, and the number of F. nucleatum was negatively correlated with the lung function of AECOPD patients. The coculture of P. aeruginosa and F. nucleatum promoted bacterial proliferation and induced antibiotic tolerance through the formation of a dense biofilm surrounded by excessive Pel and Psl polysaccharides. Moreover, Fusobacterium adhesin A (FadA), rather than F. nucleatum spent medium, induced antibiotic tolerance of the P. aeruginosa biofilm. These results indicate that F. nucleatum is a biomarker of lung function decline in AECOPD patients and interacts with P. aeruginosa in vitro to resist antibiotics via FadA, which would be a potential anti-infective target of these dual-species infection.

Biofilm formation on three different endotracheal tubes: a prospective clinical trial

BACKGROUND

Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation.

METHODS

We compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP.

RESULTS

High-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14-15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06-0.59], p = 0.005, and OR 0.34 [95% CI 0.13-0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17-1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation.

CONCLUSION

High-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02284438 . Retrospectively registered on 21 October 2014.

The impact of tooth brushing versus tooth brushing and chlorhexidine application to avoid postoperative pneumonia in children

BACKGROUND

The pathogenesis of postsurgical pneumonia is a complicated and multifactorial process, in which elements like oral bacteria, orotracheal intubation, and dental hygiene play an important role. The objective of this study was to evaluate the efficacy of 2 types of oral hygiene interventions in decreasing cases of postsurgical pneumonia.

METHODS

In pediatric patients scheduled for surgery, a quasi-experimental study was carried out over a 2-year period to evaluate the efficacy of 2 types of oral hygiene interventions. There were 2 groups of intervention with 1 group for comparison. Intervention groups were tooth brushing by a dentist (intervention group 1) and dental brushing by parents + chlorhexidine gluconate (intervention group 2). Data from the year with no oral hygiene interventions were used as the baseline group.

RESULTS

A total of 2,535 surgical procedures were followed. Baseline group incidence of postoperative pneumonia was 10 per 1,000 surgeries, 0.2 per 1,000 surgeries in the intervention group 1 (P = .04), and 0.8 per 1,000 surgeries in the intervention group 2. Intervention group 1 was protective against postoperative pneumonia (odds ratio, 0.06; P = .02; 95% confidence interval, 0.033-0.079), but there was no benefit with intervention group 2 (odds ratio, 0.87; P = .599; 95% confidence interval, 0.52-1.46).

CONCLUSIONS

Dental brushing performed before surgery by a pediatric dentist was effective in reducing the incidence of postoperative pneumonia in pediatric patients.

Recent progress in experimental and human disease-associated multi-species biofilms

Human bodies are colonized by trillions of microorganisms, which are often referred to as human microbiota and play important roles in human health. Next generation sequencing studies have established links between the genetic content of human microbiota and various human diseases. However, it remains largely unknown about the spatial organizations and interspecies interactions of individual species within the human microbiota. Bacterial cells tend to form surface-attached biofilms in many natural environments, which enable intercellular communications and interactions in a microbial ecosystem. In this review, we summarize the recent progresses on the experimental and human disease-associated multi-species biofilm studies. We hypothesize that engineering biofilm structures and interspecies interactions might provide a tool for manipulating the composition and function of human microbiota.

Protocol for a multi-centered, stepped wedge, cluster randomized controlled trial of the de-adoption of oral chlorhexidine prophylaxis and implementation of an oral care bundle for mechanically ventilated critically ill patients: the CHORAL study

BACKGROUND

Routine application of chlorhexidine oral rinse is recommended to reduce risk of ventilator-associated pneumonia (VAP) in mechanically ventilated patients. Recent reappraisal of the evidence from two meta-analyses suggests chlorhexidine may cause excess mortality in non-cardiac surgery patients and does not reduce VAP. Mechanisms for possible excess mortality are unclear. The CHORAL study will evaluate the impact of de-adopting chlorhexidine and implementing an oral care bundle (excluding chlorhexidine) on mortality, infection-related ventilator-associated complications (IVACs), and oral health status.

METHODS

The CHORAL study is a stepped wedge, cluster randomized controlled trial in six academic intensive care units (ICUs) in Toronto, Canada. Clusters (ICU) will be randomly allocated to six sequential steps over a 14-month period to de-adopt oral chlorhexidine and implement a standardized oral care bundle (oral assessment, tooth brushing, moisturization, and secretion removal). On study commencement, all clusters begin with a control period in which the standard of care is oral chlorhexidine. Clusters then begin crossover from control to intervention every 2 months according to the randomization schedule. Participants include all mechanically ventilated adults eligible to receive the standardized oral care bundle. The primary outcome is ICU mortality; secondary outcomes are IVACs and oral health status. We will determine demographics, antibiotic usage, mortality, and IVAC rates from a validated local ICU clinical registry. With six clusters and 50 ventilated patients on average each month per cluster, we estimate that 4200 patients provide 80% power after accounting for intracluster correlation to detect an absolute reduction in mortality of 5.5%. We will analyze our primary outcome of mortality using a generalized linear mixed model adjusting for time to account for secular trends. We will conduct a process evaluation to determine intervention fidelity and to inform interpretation of the trial results.

DISCUSSION

The CHORAL study will inform understanding of the effectiveness of de-adoption of oral chlorhexidine and implementation of a standardized oral care bundle for decreasing ICU mortality and IVAC rates while improving oral health status. Our process evaluation will inform clinicians and decision makers about intervention delivery to support future de-adoption if justified by trial results.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03382730 . Registered on December 26, 2017.

The microbiome: implications for perioperative and critical care

PURPOSE OF REVIEW

The host-microbiota relationship is integral in human health and can be rapidly disrupted in ways that may contribute to poor recovery from surgery or acute illness. We review key studies by organ system to understand the effect of perioperative and critical illness stress on the microbiota. Throughout the review, our focus is on potential interventions that may be mediated by the microbiome.

RECENT FINDINGS

Although any perioperative intervention can have a profound impact on the gut microbiota, it is less clear how such changes translate into altered health outcomes. Preoperative stress (anxiety, lack of sleep, fasting), intraoperative stress (surgery itself, volatile anesthetics, perioperative antibiotics, blood transfusions), and postoperative stress (sepsis, surgical site infections, acute respiratory distress syndrome, catecholamines, antibiotics, opioids, proton pump inhibitors) have all been associated with alterations of the commensal microflora. These factors (e.g. administration of antibiotics or opioids) can create a favorable environment for emergence of pathogen virulence and development of serious infections and multiorgan failure. Data to recommend therapies aimed at restoring a disrupted microbiota, such as probiotics/prebiotics and fecal microbiota transplants is currently scarce.

SUMMARY

The microbiome is likely to play an important role in the perioperative and ICU setting but existing data is largely descriptive. There is an expanding number of mechanistic studies that attempt to disentangle the complicated bi-directional relationship between the host and the resident microbiota. When these results are combined with ongoing clinical studies, we should be able to offer better therapies aimed at restoring the microbiota in the future.

Exploration of difficulty accessing the mouths of intubated and mechanically ventilated adults for oral care: A video and photographic elicitation study

AIM

To explore descriptors of difficulty accessing the mouths of intubated and mechanically ventilated adults for oral care, consequences, modifiable antecedents and recommendations for improving care delivery.

BACKGROUND

Nurses report oral access and care delivery difficulty in most mechanically ventilated patients.

DESIGN

A prospective qualitative descriptive design.

METHODS

Data were collected using video and photographic elicitation interviews focused on delivery of oral care. Directed content analysis was used to explore descriptive categories. Reporting used the SRQR guidelines.

SETTING AND PARTICIPANTS

A university-affiliated hospital in Toronto, Canada. Participants included clinicians experienced in accessing the oral space of adults representing nursing, medicine, dentistry and allied health professionals.

FINDINGS

We recruited 18 participants; 9 representing critical care and 9 other specialties frequently accessing the mouth, that is dentistry. Descriptors for observed difficulty accessing the oral cavity were "oral crowding with tubes" and "aversive patient responses", which were considered to result in insufficient oral care. Participants perceived aversive patient responses (e.g. biting, turning head side to side, gagging, coughing) as a consequence of forced introduction of instruments inside a crowded mouth. A key finding identified by participants was the observation of substantial procedural pain during oral care interventions. Potentially modifiable antecedents to difficult oral care delivery identified were procedural pain, oral health deterioration (e.g. xerostomia) and lack of interprofessional team problem-solving. Recommendations to address these antecedents included patient preparation for oral care through verbal and nonverbal cueing, pharmacological and nonpharmacological strategies, and ICU interprofessional education.

CONCLUSIONS

Oral care in mechanically ventilated adults is complex and painful. Visual research methods offer important advantages for oral care exploration including its ability to reveal less visible aspects of the nurse-patient encounter, thereby enabling novel insights and care.

RELEVANCE FOR CLINICAL PRACTICE

Interprofessional education and training in oral health and care interventions tailored to mechanically ventilated patients are recommended.

Risk factors of ventilator-associated pneumonia in elderly patients receiving mechanical ventilation

Purpose: The aim of this study was to verify the potential risk factors of ventilator-associated pneumonia (VAP) in elderly Chinese patients receiving mechanical ventilation (MV). The secondary aim of this study was to present logistical regression prediction models of VAP occurrence in elderly Chinese patients receiving MV. Methods: Patients (aged 80 years or above) receiving MV for ≥48 h were enrolled from the Chinese People's Liberation Army (PLA) General Hospital from January 2011 to December 2015. A chi-squared test and Mann-Whitney U-test were used to compare the data between participants with VAP and without VAP. Univariate logistic regression models were performed to explore the relationship between risk factors and VAP. Results: A total of 901 patients were included in the study, of which 156 were diagnosed as VAP (17.3%). The incidence density of VAP was 4.25/1,000 ventilator days. Logistic regression analysis showed that the independent risk factors for elderly patients with VAP were COPD (OR =1.526, P < 0.05), intensive care unit (ICU) admission (OR=1.947, P < 0.01), the MV methods (P < 0.023), the number of antibiotics administered (OR=4.947, P < 0.01), the number of central venous catheters (OR=1.809, P < 0.05), the duration of indwelling urinary catheter (OR=1.805, P < 0.01) and the use of corticosteroids prior to MV (OR=1.618, P < 0.05). Logistic regression prediction model of VAP occurrence in the Chinese elderly patients with mechanical ventilation:L o g i t   P = - 6 . 468 + 0 . 423 X 1 + 0 . 666 X 2 + 0 . 871 X 3 + - 0 . 501 X 5 + 0 . 122 X 6 + 0 . 593 X 7 + 0 . 590 X 8 + 1 . 599 X 9 . Conclusion: VAP occurrence is associated with a variety of controllable factors including the MV methods and the number of antibiotics administered. A model was established to predict VAP occurrence so that high-risk patients could be identified as early as possible.

Molecular analysis of the endobronchial stent microbial biofilm reveals bacterial communities that associate with stent material and frequent fungal constituents

Endobronchial stents are increasingly used to treat airway complications in multiple conditions including lung transplantation but little is known about the biofilms that form on these devices. We applied deep sequencing to profile luminal biofilms of 46 endobronchial stents removed from 20 subjects primarily with lung transplantation-associated airway compromise. Microbial communities were analyzed by bacterial 16S rRNA and fungal ITS marker gene sequencing. Corynebacterium was the most common bacterial taxa across biofilm communities. Clustering analysis revealed three bacterial biofilm types: one low diversity and dominated by Corynebacterium; another was polymicrobial and characterized by Staphylococcus; and the third was polymicrobial and associated with Pseudomonas, Streptococcus, and Prevotella. Biofilm type was significantly correlated with stent material: covered metal with the Staphylococcus-type biofilm, silicone with the Corynebacterium-dominated biofilm, and uncovered metal with the polymicrobial biofilm. Subjects with sequential stents had frequent transitions between community types. Fungal analysis found Candida was most prevalent, Aspergillus was common and highly enriched in two of three stents associated with airway anastomotic dehiscence, and fungal taxa not typically considered pathogens were highly enriched in some stents. Thus, molecular analysis revealed a complex and dynamic endobronchial stent biofilm with three bacterial types that associate with stent material, a central role for Corynebacterium, and that both expected and unexpected fungi inhabit this unique niche. The current work provides a foundation for studies to investigate the relationship between stent biofilm composition and clinical outcomes, mechanisms of biofilm establishment, and strategies for improved stent technology and use in airway compromise.

Help, hinder, hide and harm: what can we learn from the interactions between Pseudomonas aeruginosa and Staphylococcus aureus during respiratory infections?

Recent studies of human respiratory secretions using culture-independent techniques have found a surprisingly diverse array of microbes. Interactions among these community members can profoundly impact microbial survival, persistence and antibiotic susceptibility and, consequently, disease progression. Studies of polymicrobial interactions in the human microbiota have shown that the taxonomic and structural compositions, and resulting behaviours, of microbial communities differ substantially from those of the individual constituent species and in ways of clinical importance. These studies primarily involved oral and gastrointestinal microbiomes. While the field of polymicrobial respiratory disease is relatively young, early findings suggest that respiratory tract microbiota members also compete and cooperate in ways that may influence disease outcomes. Ongoing efforts therefore focus on how these findings can inform more 'enlightened', rational approaches to combat respiratory infections. Among the most common respiratory diseases involving polymicrobial infections are cystic fibrosis (CF), non-CF bronchiectasis, COPD and ventilator-associated pneumonia. While respiratory microbiota can be diverse, two of the most common and best-studied members are Staphylococcus aureus and Pseudomonas aeruginosa, which exhibit a range of competitive and cooperative interactions. Here, we review the state of research on pulmonary coinfection with these pathogens, including their prevalence, combined and independent associations with patient outcomes, and mechanisms of those interactions that could influence lung health. Because P. aeruginosa-S. aureus coinfection is common and well studied in CF, this disease serves as the paradigm for our discussions on these two organisms and inform our recommendations for future studies of polymicrobial interactions in pulmonary disease.

Integrating host response and unbiased microbe detection for lower respiratory tract infection diagnosis in critically ill adults

Lower respiratory tract infections (LRTIs) are the leading cause of infectious disease-related deaths worldwide yet remain challenging to diagnose because of limitations in existing microbiologic tests. In critically ill patients, noninfectious respiratory syndromes that resemble LRTIs further complicate diagnosis and confound targeted treatment. To address this, we developed a metagenomic sequencing-based approach that simultaneously interrogates three core elements of acute airway infections: the pathogen, airway microbiome, and host response. We studied this approach in a prospective cohort of critically ill patients with acute respiratory failure and found that combining pathogen, microbiome, and host gene expression metrics achieved accurate LRTI diagnosis and identified etiologic pathogens in patients with clinically identified infections but otherwise negative testing.

Lower respiratory tract infections (LRTIs) lead to more deaths each year than any other infectious disease category. Despite this, etiologic LRTI pathogens are infrequently identified due to limitations of existing microbiologic tests. In critically ill patients, noninfectious inflammatory syndromes resembling LRTIs further complicate diagnosis. To address the need for improved LRTI diagnostics, we performed metagenomic next-generation sequencing (mNGS) on tracheal aspirates from 92 adults with acute respiratory failure and simultaneously assessed pathogens, the airway microbiome, and the host transcriptome. To differentiate pathogens from respiratory commensals, we developed a rules-based model (RBM) and logistic regression model (LRM) in a derivation cohort of 20 patients with LRTIs or noninfectious acute respiratory illnesses. When tested in an independent validation cohort of 24 patients, both models achieved accuracies of 95.5%. We next developed pathogen, microbiome diversity, and host gene expression metrics to identify LRTI-positive patients and differentiate them from critically ill controls with noninfectious acute respiratory illnesses. When tested in the validation cohort, the pathogen metric performed with an area under the receiver-operating curve (AUC) of 0.96 (95% CI, 0.86–1.00), the diversity metric with an AUC of 0.80 (95% CI, 0.63–0.98), and the host transcriptional classifier with an AUC of 0.88 (95% CI, 0.75–1.00). Combining these achieved a negative predictive value of 100%. This study suggests that a single streamlined protocol offering an integrated genomic portrait of pathogen, microbiome, and host transcriptome may hold promise as a tool for LRTI diagnosis.

The microbiome in mechanically ventilated patients

PURPOSE OF REVIEW

Discovery of a normal lung microbiome requires reassessment of our concepts of HAP/VAP pathogenesis and has important implications for clinical diagnosis and management.

RECENT FINDINGS

Changes in the microbiome of dental plaque are associated with increased risk of HAP/VAP. A transition to a lung microbiome enriched with gut flora is found in ARDS with an increased inflammatory response in patients with this change in microbial flora. A characteristic microbiome pattern of higher amounts of bacterial DNA, lower community diversity, and greater relative abundance of a single species characterize pneumonia and occasionally identify bacteria not found in culture. The influence of the microbiome makes probiotics a logical strategy to prevent or ameliorate HAP/VAP but so far clinical support is unclear.

SUMMARY

The presence of a normal lung microbiome and the interaction of that microbiome with other microbiota have an important but previously overlooked impact on the pathogenesis of HAP/VAP. Deep sequencing suggests that the repertoire of microorganisms and the pattern of bacterial communities associated with HAP/VAP remains incompletely understood but recent studies are adding greater clarity.

Prevalence and predictors of difficulty accessing the mouths of intubated critically ill adults to deliver oral care: An observational study

BACKGROUND

Oral care of intubated patients is essential to the prevention of infection and patient discomfort. However, barriers to oral access and delivery of oral care have received little attention.

OBJECTIVE

To determine prevalence and predictors of oral access difficulty.

DESIGN

A prospective, observational, multi-center study.

SETTINGS

Four intensive care units in Toronto, Canada.

PARTICIPANTS

Adult patients orally intubated for ≥48 h.

METHODS

We screened consecutive admissions once a week to identify eligible participants. We observed each patient and asked the patient's nurse about presence or absence of difficulty accessing the mouth to deliver oral care across three categories: (1) visualizing inside the mouth; (2) obtaining patient cooperation, or (3) inserting instruments for delivery of oral care. We asked nurses to identify presence of patient behaviors contributing to oral access difficulty and perceived level of difficulty on a Likert response scale. We examined patient and treatment characteristics associated with extreme difficulty (i.e., difficulty in all 3 categories) using a generalized estimating equation regression model.

RESULTS

A total of 428 patients were observed, 58% admitted with a medical diagnosis. More than half (57%) had ≥2 oral devices up to maximum of 4. Oral care difficulty was identified in 83% of patients and rated as moderate to high for 217 (51%). Difficulty concerned visibility (74%), patient cooperation (55%), and space to insert instruments (53%). Patient behaviors contributing difficulty included coughing/gagging (60%), mouth closing (49%), biting (45%) and localizing (27%) during care. Variables associated with extreme difficulty included neurological (OR 1.92, 95% CI 1.42-2.60) or trauma admission (OR 1.83, 95% CI 1.16-2.89), lack of pain assessment or treatment in the 4 h prior to oral care (OR 1.43, 95% CI 1.14-1.80), more oral devices (OR 1.40, 95% CI 1.05-1.87), and duration of intubation (OR 1.05, 95% CI 1.01-1.10). Absence of documented agitation in the 4 h prior to oral care was associated with less difficulty (OR 0.68, 95% CI 0.54-0.86).

CONCLUSIONS

Oral care is complex and difficulties are experienced in a vast majority of intubated patients. Some difficulties are amenable to correction such as pain management.

Factors associated with oral biofilm in ICU patients with infectious diseases

Abstract Introduction Hospitalization may cause a decline in oral health and affect the entire body. The intensive care unit (ICU) may be a favorable environment for oral biofilm to accumulate in critically ill patients. Objective To identify factors associated with oral biofilm in ICU patients in a hospital for infectious diseases. Method This was a retrospective, descriptive and inferential study with a quantitative approach. Data were collected from 178 medical records of patients from January 2012 to July 2015. Biofilm presence was assessed according to the Greene and Vermillion index. Potential influential factors were analyzed by logistic regression. Result Among ICU patients, 69.1% were men, 60.7% had acquired immune deficiency (AIDS), 66.3% were ward patients, 50.6% were intubated, and 50.0% were sedated. The oral elements of the patients were mostly normal. The following characteristics were significantly associated with oral biofilm: changes in the lips, gums, cheeks, and palates and bleeding. Patients from the ward had a lower risk of biofilm. Conclusion Increased oral biofilm accumulation was observed in patients with oral changes, and patient origin was associated with the presence of biofilm.

Association between oral health and upper respiratory tract infection among children

BACKGROUND

The oral cavity is a potential reservoir for respiratory pathogens. This longitudinal study investigated the association between upper respiratory tract infection (URI) and oral health among children.

METHODS

A total of 288 children aged 4 years were recruited. Their dental caries and oral hygiene status were clinically determined, using the dmft (decayed, missing and filled teeth) index and the Silness-Löe plaque index. Questionnaires were completed by parents to collect information on the child's socio-demographic background and URI episodes and symptoms in the following 12 months. Standard or zero-inflated negative binomial regressions were used to analyse the association between URI and both oral health indicators (dmft and plaque score).

RESULTS

Some 138 (47.9%) children had URI in 12 months, including 63 (21.9%) and 75 (26.0%) children with 1-2 episodes and ≥3 episodes, respectively. The reported URI episodes fell into two peaks, coinciding with the two influenza peaks in Hong Kong. Significantly a higher dmft was found among children without URI compared with children who had ≥3 URI episodes (1.32 vs. 0.49; P = 0.043). The number of URI episodes was inversely associated with dmft (IRR = 0.851; 95% CI: 0.766-0.945; P = 0.003). There was no significant association between the plaque score and URI (P > 0.05).

CONCLUSIONS

The children's caries experience was associated with reduced episodes of URI. Whether this inverse association is attributed to the immune response induced by dental caries is yet to be investigated.

Analysis of biofilm production by clinical isolates of Pseudomonas aeruginosa from patients with ventilator-associated pneumonia

Objective

To phenotypically evaluate biofilm production by Pseudomonas aeruginosa clinically isolated from patients with ventilator-associated pneumonia.

Methods

Twenty clinical isolates of P. aeruginosa were analyzed, 19 of which were from clinical samples of tracheal aspirate, and one was from a bronchoalveolar lavage sample. The evaluation of the capacity of P. aeruginosa to produce biofilm was verified using two techniques, one qualitative and the other quantitative.

Results

The qualitative technique showed that only 15% of the isolates were considered biofilm producers, while the quantitative technique showed that 75% of the isolates were biofilm producers. The biofilm isolates presented the following susceptibility profile: 53.3% were multidrug-resistant, and 46.7% were multidrug-sensitive.

Conclusion

The quantitative technique was more effective than the qualitative technique for the detection of biofilm production. For the bacterial population analyzed, biofilm production was independent of the susceptibility profile of the bacteria, demonstrating that the therapeutic failure could be related to biofilm production, as it prevented the destruction of the bacteria present in this structure, causing complications of pneumonia associated with mechanical ventilation, including extrapulmonary infections, and making it difficult to treat the infection.

Pathogenic Link Between Postextubation Pneumonia and Ventilator-Associated Pneumonia: An Experimental Study

BACKGROUND

The presence of an endotracheal tube is the main cause for developing ventilator-associated pneumonia (VAP), but pneumonia can still develop in hospitalized patients after endotracheal tube removal (postextubation pneumonia [PEP]). We hypothesized that short-term intubation (24 hours) can play a role in the pathogenesis of PEP. To test such hypothesis, we initially evaluated the occurrence of lung colonization and VAP in sheep that were intubated and mechanically ventilated for 24 hours. Subsequently, we assessed the incidence of lung colonization and PEP at 48 hours after extubation in sheep previously ventilated for 24 hours.

METHODS

To simulate intubated intensive care unit patients placed in semirecumbent position, 14 sheep were intubated and mechanically ventilated with the head elevated 30° above horizontal. Seven of them were euthanized after 24 hours (Control Group), whereas the remaining were euthanized after being awaken, extubated, and left spontaneously breathing for 48 hours after extubation (Awake Group). Criteria of clinical diagnosis of pneumonia were tested. Microbiological evaluation was performed on autopsy in all sheep.

RESULTS

Only 1 sheep in the Control Group met the criteria of VAP after 24 hours of mechanical ventilation. However, heavy pathogenic bacteria colonization of trachea, bronchi, and lungs (range, 10-10 colony-forming unit [CFU]/g) was reported in 4 of 7 sheep (57%). In the Awake Group, 1 sheep was diagnosed with VAP and 3 developed PEP within 48 hours after extubation (42%), with 1 euthanized at 30 hours because of respiratory failure. On autopsy, 5 sheep (71%) confirmed pathogenic bacterial growth in the lower respiratory tract (range, 10-10 CFU/g).

CONCLUSIONS

Twenty-four hours of intubation and mechanical ventilation in semirecumbent position leads to significant pathogenic colonization of the lower airways, which can promote the development of PEP. Strategies directed to prevent pathogenic microbiological colonization before and after mechanical ventilation should be considered to avert the onset of PEP.

Association between pathogens from tracheal aspirate and oral biofilm of patients on mechanical ventilation

The aim of this study was to detect possible associations between respiratory pathogens from tracheal aspirate and oral biofilm samples in intubated patients in an intensive care unit (ICU), and to identify the most common respiratory pathogens in oral biofilm, particularly in patients that developed ventilator-associated pneumonia (VAP). Two oral biofilm samples were collected from the tongue of intubated patients (at admission and after 48 hours) and analyzed by culture with the Antibiotic Sensitivity Test. The results from the tongue biofilm samples were compared with the tracheal secretions samples. A total of 59.37% of patients exhibited the same species of pathogens in their tracheal aspirate and oral biofilm, of which 8 (42.1%) developed VAP, 10 (52.63%) did not develop pneumonia and one (5.26%) had aspiration pneumonia. There was a statistically significant association between presence of microorganisms in the tracheal and mouth samples for the following pathogens: Klebsiella pneumoniae, Candida albicans, Pseudomonas aeruginosa, Enterobacter gergoviae, Streptococcus spp and Serratia marcescens (p < 0.05). Pathogens that are present in tracheal aspirates of intubated patients can be detected in their oral cavity, especially in those who developed VAP or aspiration pneumonia. Thus, the results indicate that an improved oral care in these patients could decrease ICU pneumonia rates.

Community analysis of dental plaque and endotracheal tube biofilms from mechanically ventilated patients

PURPOSE

Mechanically ventilated patients are at risk for developing ventilator-associated pneumonia, and it has been reported that dental plaque provides a reservoir of respiratory pathogens that may aspirate to the lungs and endotracheal tube (ETT) biofilms. For the first time, metataxonomics was used to simultaneously characterize the microbiome of dental plaque, ETTs, and non-directed bronchial lavages (NBLs) in mechanically ventilated patients to determine similarities in respective microbial communities and therefore likely associations.

MATERIAL AND METHODS

Bacterial 16S rRNA gene sequences from 34 samples of dental plaque, NBLs, and ETTs from 12 adult mechanically ventilated patients were analyzed.

RESULTS

No significant differences in the microbial communities of these samples were evident. Detected bacteria were primarily oral species (e.g., Fusobacterium nucleatum, Streptococcus salivarius, Prevotella melaninogenica) with respiratory pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcuspneumoniae, and Haemophilus influenzae) also in high abundance.

CONCLUSION

The high similarity between the microbiomes of dental plaque, NBLs, and ETTs suggests that the oral cavity is indeed an important site involved in microbial aspiration to the lower airway and ETT. As such, maintenance of good oral hygiene is likely to be highly important in limiting aspiration of bacteria in this vulnerable patient group.

Human Salivary Protein Histatin 5 Has Potent Bactericidal Activity against ESKAPE Pathogens

ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter species) pathogens have characteristic multiple-drug resistance and cause an increasing number of nosocomial infections worldwide. Peptide-based therapeutics to treat ESKAPE infections might be an alternative to conventional antibiotics. Histatin 5 (Hst 5) is a salivary cationic histidine-rich peptide produced only in humans and higher primates. It has high antifungal activity against Candida albicans through an energy-dependent, non-lytic process; but its bactericidal effects are less known. We found Hst 5 has bactericidal activity against S. aureus (60–70% killing) and A. baumannii (85–90% killing) in 10 and 100 mM sodium phosphate buffer (NaPB), while killing of >99% of P. aeruginosa, 60–80% E. cloacae and 20–60% of E. faecium was found in 10 mM NaPB. Hst 5 killed 60% of biofilm cells of P. aeruginosa, but had reduced activity against biofilms of S. aureus and A. baumannii. Hst 5 killed 20% of K. pneumonia biofilm cells but not planktonic cells. Binding and uptake studies using FITC-labeled Hst 5 showed E. faecium and E. cloacae killing required Hst 5 internalization and was energy dependent, while bactericidal activity was rapid against P. aeruginosa and A. baumannii suggesting membrane disruption. Hst 5-mediated killing of S. aureus was both non-lytic and energy independent. Additionally, we found that spermidine conjugated Hst 5 (Hst5-Spd) had improved killing activity against E. faecium, E. cloacae, and A. baumannii. Hst 5 or its derivative has antibacterial activity against five out of six ESKAPE pathogens and may be an alternative treatment for these infections.