Diagnosis of ventilator-associated pneumonia: controversies and working toward a gold standard. Curr Opin Infect Dis. 2013;26:140-150. [PMID: 23411419 DOI: 10.1097/QCO.0b013e32835ebbd0]

Impact of a Multiplex PCR Assay for Rapid Diagnosis and Antibiotic Utilization in Trauma Intensive Care Unit Patients with Ventilator-Acquired Pneumonia

Background: Ventilator-associated pneumonia (VAP) is a frequent complication in injured patients. Multiplex polymerase chain reaction (PCR) facilitates rapid identification of many respiratory pathogens prior to formal culture results. Our objective was to evaluate the effect of multiplex PCR implementation in a trauma intensive care unit (TICU) on antibiotic utilization and de-escalation. Patients and Methods: Injured adult patients admitted to the TICU with quantitative respiratory cultures were included. Patients were dichotomized into two groups, before (PRE) or after (POST) implementation of the pneumonia (PNA) panel. The PRE cohort included all patients meeting study criteria from January to June 2021, and the POST cohort included all patients meeting study criteria from January to June 2022, Patients were excluded if there was any documented infection requiring antibiotics other than a respiratory source. Results: During the study period, 60 patients met criteria for inclusion, 30 PRE and 30 POST. Diagnosis of VAP was confirmed in 43.3% PRE and 50% POST patients. The time to antibiotic change was substantially shorter in the POST group (23 h vs. 61 h, p < 0.001). In the POST cohort, 83% of initial antibiotic regimens were eligible for change on the basis of PNA panel. Of these, 88% were changed in a median time of 15.4 h. In all patients, total days of antibiotic therapy (DOT) were not different (9 vs. 10, p = 0.207); however, vancomycin DOT was less in the POST group (2 d vs. 3 d, p ≤ 0.001). In those patients diagnosed with VAP, the total antibiotic (10 vs. 12 d p = 0.008), vancomycin (2 vs. 3 d p = 0.003), and cefepime DOT (3 vs. 4 d 0.029) were substantially less in the POST group. Conclusions: Utilization of multiplex PCR in addition to bacterial culture substantially reduced time to achieve targeted antibiotic therapy in suspected pneumonia. Furthermore, it reduced the number of days of vancomycin therapy.

Bacteriological Profile of Nosocomial Pneumonia and Current State of Antibiotic Resistance in the Military Hospital of Avicenne

This retrospective study, conducted over five years, aimed to assess the bacteriological profile of nosocomial pneumonia, the antibiotic resistance of isolated bacteria, and changes in these parameters over time. The analysis reviewed 660 samples from the microbiology department at the Military Hospital of Avicenne in Marrakech, Morocco, covering the period from January 1, 2017, to December 31, 2021. Among these samples, 303 microorganisms were identified from 251 specimens, confirming diagnoses of nosocomial pneumonia. Microorganism identification and antibiograms were performed using the Phoenix100 automated system from Becton Dickinson. The results revealed that 73% of the isolated microorganisms were Gram-negative bacilli, with Acinetobacter baumannii (29.4%) being the most common, followed by Enterobacteriaceae (28%), particularly Klebsiella pneumoniae (15.5%) and Pseudomonas aeruginosa (10.9%). Gram-positive cocci made up 22.5% of isolates, with Staphylococcus aureus (15.2%) being the most prevalent, while yeasts were present in 3.6% of cases. A polymicrobial nature was observed in 19.12% of samples. A. baumannii strains showed high resistance to most antibiotics, with an imipenem resistance rate of 88.5%; colistin was the only effective agent against these strains. In contrast, P. aeruginosa exhibited broad sensitivity to antibiotics, with only an 11.1% resistance rate to ceftazidime and good sensitivity to imipenem (80%). Extended-spectrum beta-lactamase production was noted in 11.5% of Enterobacteriaceae, mainly K. pneumoniae. Methicillin-resistant S. aureus prevalence was low at 11.6%, and all S. aureus strains were vancomycin-sensitive. The study highlights the importance of prudent antibiotic use, enhanced hospital hygiene practices, and ongoing monitoring of bacterial resistance. These measures are vital for developing therapeutic strategies suited to local epidemiology and reducing infections caused by multidrug-resistant microorganisms.

Comparing the Accuracy of Mini-BAL to Bronchoscopic BAL in the Diagnosis of Pneumonia Among Ventilated Patients: A Systematic Literature Review

Background: Despite its widespread use, there are no direct studies comparing mini-bronchoalveolar lavage (mini-BAL) to bronchoscopic bronchoalveolar lavage (BAL) for diagnosing pneumonia in ventilated patients. The aim of this study was to perform a systematic review of studies comparing ventilated patients undergoing both bronchoscopic BAL and mini-BAL, to determine the mini-BAL's diagnostic accuracy. Methods: We conducted a systematic review searching the databases PubMed (MEDLINE), EMBASE, Cochrane Library, Scopus, and clinicaltrials.gov from inception until January 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included variations on "pneumonia," "critical illness," and "mini-bronchoalveolar lavage." Article screening and data extraction were performed independently by 2 reviewers. Results: Our search yielded 4296 abstracts. This was narrowed to 6 studies in which each patient underwent both mini-BAL and bronchoscopic BAL in succession. Included patients had a mean APACHE II score of 20.02 ± 3.81 and 15.95 ± 11.46 ventilator days. The sensitivity of the mini-BAL for diagnosis of pneumonia was 0.90 (95% confidence interval [CI]: 0.778-1.000) and the specificity was 0.827 (95% CI: 0.716-0.938). Limitations included inconsistency in volume of saline instilled and heterogeneity in included patients Conclusion: This study is the first to compile data from multiple publications directly comparing the mini-BAL to bronchoscopic BAL for diagnosing pneumonia in ventilated patients. Our data demonstrate a high degree of both sensitivity and specificity of mini-BAL for the diagnosis of pneumonia in ventilated patients and indicate that mini-BAL could be considered as an acceptable alternative diagnostic study.

Challenging the Interpretation of White Blood Cell Counts in Patients with Sepsis Following Packed Cell Transfusion

Critically ill patients with sepsis often require packed cell transfusions (PCT). However, PCT may affect white blood cell (WBC) counts. We conducted a population-based retrospective cohort study to trace changes in WBC count following PCT in critically ill patients with sepsis. We included 962 patients who received one unit of PCT while hospitalized in a general intensive care unit, and 994 matched patients who did not receive PCT. We calculated the mean values of WBC count for the 24 h before and 24 h after PCT. Multivariable analyses using a mixed linear regression model were performed. The mean WBC count decreased in both groups, but more in the non-PCT group (from 13.9 × 10⁹/L to 12.2 × 10⁹/L versus 13.9 × 10⁹/L to 12.8 × 10⁹/L). A linear regression model showed a mean decrease of 0.45 × 10⁹/L in WBC count over the 24 h following the start of PCT. Every 1.0 × 10⁹/L increase in the WBC count prior to PCT administration showed a corresponding decrease of 0.19 × 10⁹/L in the final WBC count. In conclusion, among critically ill patients with sepsis, PCT causes only mild and clinically non-prominent changes in WBC count.

Respiratory metagenomics: route to routine service

PURPOSE OF REVIEW

The coronavirus disease 2019 pandemic demonstrated broad utility of pathogen sequencing with rapid methodological progress alongside global distribution of sequencing infrastructure. This review considers implications for now moving clinical metagenomics into routine service, with respiratory metagenomics as the exemplar use-case.

RECENT FINDINGS

Respiratory metagenomic workflows have completed proof-of-concept, providing organism identification and many genotypic antimicrobial resistance determinants from clinical samples in <6 h. This enables rapid escalation or de-escalation of empiric therapy for patient benefit and reducing selection of antimicrobial resistance, with genomic-typing available in the same time-frame. Attention is now focussed on demonstrating clinical, health-economic, accreditation, and regulatory requirements. More fundamentally, pathogen sequencing challenges the traditional culture-orientated time frame of microbiology laboratories, which through automation and centralisation risks becoming increasingly separated from the clinical setting. It presents an alternative future where infection experts are brought together around a single genetic output in an acute timeframe, aligning the microbiology target operating model with the wider human genomic and digital strategy.

SUMMARY

Pathogen sequencing is a transformational proposition for microbiology laboratories and their infectious diseases, infection control, and public health partners. Healthcare systems that link output from routine clinical metagenomic sequencing, with pandemic and antimicrobial resistance surveillance, will create valuable tools for protecting their population against future infectious diseases threats.

Human exhaled air diagnostic markers for respiratory tract infections in subjects receiving mechanical ventilation

Diagnosing respiratory tract infections (RTIs) in critical care settings is essential for appropriate antibiotic treatment and lowering mortality. The current diagnostic method, which primarily relies on clinical symptoms, lacks sensitivity and specificity, resulting in incorrect or delayed diagnoses, putting patients at a heightened risk. In this study we developed a noninvasive diagnosis method based on collecting non-volatile compounds in human exhaled air. We hypothesized that non-volatile compound profiles could be effectively used for bacterial RTI diagnosis. Exhaled air samples were collected from subjects receiving mechanical ventilation diagnosed with or without bacterial RTI in intensive care units at the Johns Hopkins Hospital. Truncated proteoforms, a class of non-volatile compounds, were characterized by top-down proteomics, and significant features associated with RTI were identified using feature selection algorithms. The results showed that three truncated proteoforms, collagen type VI alpha three chain protein, matrix metalloproteinase-9, and putative homeodomain transcription factor II were independently associated with RTI with thep-values of 2.0 × 10^-5, 1.1 × 10^-4, and 1.7 × 10^-3, respectively, using multiple logistic regression. Furthermore, a score system named 'TrunScore' was constructed by combining the three truncated proteoforms, and the diagnostic accuracy was significantly improved compared to that of individual truncated proteoforms, with an area under the receiver operator characteristic curve of 96.9%. This study supports the ability of this noninvasive breath analysis method to provide an accurate diagnosis for RTIs in subjects receiving mechanical ventilation. The results of this study open the doors to be able to potentially diagnose a broad range of diseases using this non-volatile breath analysis technique.

Infection-Related Ventilator-Associated Complications in Critically Ill Patients with Trauma: A Retrospective Analysis

BACKGROUND

Trauma is a leading cause of death and disability. Patients with trauma undergoing invasive mechanical ventilation (IMV) are at risk for ventilator-associated events (VAEs) potentially associated with a longer duration of IMV and increased stay in the intensive care unit (ICU).

METHODS

We conducted a retrospective cohort study aimed to evaluate the incidence of infection-related ventilator-associated complications (IVACs), possible ventilator-associated pneumonia (PVAP), and their characteristics among patients experiencing severe trauma that required ICU admission and IMV for at least four days. We also determined pathogens implicated in PVAP episodes and characterized the use of antimicrobial therapy.

RESULTS

In total, 88 adult patients were included in the main analysis. In this study, we observed that 29.5% of patients developed a respiratory infection during ICU stay. Among them, five patients (19.2%) suffered from respiratory infections due to multi-drug resistant bacteria. Patients who developed IVAC/PVAP presented lower total GCS (median value, 7; (IQR, 9) vs. 12.5, (IQR, 8); p = 0.068) than those who did not develop IVAC/PVAP.

CONCLUSIONS

We observed that less than one-third of trauma patients fulfilling criteria for ventilator associated events developed a respiratory infection during the ICU stay.

Molecular Characterization and Antibiogram of Acinetobacter baumannii Clinical Isolates Recovered from the Patients with Ventilator-Associated Pneumonia

A 2-year prospective study carried out on ventilator-associated pneumonia (VAP) patients in the intensive care unit at a tertiary care hospital, Hail, Kingdom of Saudi Arabia (KSA), revealed a high prevalence of extremely drug-resistant (XDR) Acinetobacter baumannii. About a 9% increase in the incidence rate of A. baumannii occurred in the VAP patients between 2019 and 2020 (21.4% to 30.7%). In 2019, the isolates were positive for IMP-1 and VIM-2 (31.1% and 25.7%, respectively) as detected by PCR. In comparison, a higher proportion of isolates produced NDM-1 in 2020. Here, we observed a high proportion of resistant ICU isolates towards the most common antibiotics in use. Colistin sensitivity dropped to 91.4% in the year 2020 as compared to 2019 (100%). Thus, the finding of this study has a highly significant clinical implementation in the clinical management strategies for VAP patients. Furthermore, strict implementation of antibiotic stewardship policies, regular surveillance programs for antimicrobial resistance monitoring, and screening for genes encoding drug resistance phenotypes have become imperative.

Colistin conditioning surfaces combined with antimicrobial treatment to prevent ventilator-associated infections

Biofilm formation on endotracheal tubes (ETT) is an important factor in the development of ventilator-associated pneumonia (VAP). This work aimed to investigate the effectiveness of colistin (COL) against the early stages of biofilm formation by Pseudomonas aeruginosa. Two strategies were used: pre-conditioning the adhesion surfaces with COL before biofilm formation and growing biofilms in its presence. The combined effect of treating P. aeruginosa 24-hours old biofilms with Ciprofloxacin (CIP) or colistin (COL) on clean and COL-conditioned surfaces was also assessed. Random deposition of COL residues altered the physico-chemical properties of the adhesion surfaces and impaired biofilm formation. Moreover, as a consequence of the reduced amount of biofilms attached to COL conditioned surfaces, adhered cells became more exposed to the subsequent action of CIP or COL, suggesting a combined outcome of prophylactic and therapeutic COL-based strategies. Results highlighted the promising use of COL to prevent the establishment of biofilms on ETT.

The influence of professional oral hygiene care on reducing ventilator-associated pneumonia in trauma intensive care unit patients

Aim This study aimed to examine the effects of professional oral hygiene care for the prevention of ventilator-associated pneumonia (VAP) and the improvement of oral hygiene among patients in the trauma intensive care unit (TICU).Materials and methods TICU patients who underwent intubation were randomly assigned to either the experimental group (n = 29) or control group (n = 28). The developed professional oral hygiene care protocol was administered to patients in the experimental group every 24 hours. Additionally, data regarding general characteristics, medical history, oral hygiene status, Clinical Pulmonary Infection Score and quantitative polymerase chain reaction were assessed.Results The incidence of VAP differed between the control group (10.58) and experimental group (0) post intervention. Post-admission bedside oral exam scores with significant differences in oral hygiene were observed in the experimental group (in contrast to the control group) from 48 hours onwards (10.69 ± 3.43, p = 0.06). Staphylococcus aureus and Klebsiella pneumoniae exhibited significant differences in count as professional oral hygiene care continued.Conclusions This study suggests a model in which different health care professionals can cooperate to reduce the incidence of VAP and improve oral health conditions.

Clinical presentation of secondary infectious complications in COVID-19 patients in intensive care unit treated with tocilizumab or standard of care

OBJECTIVES

The hypothesis of this study is that tocilizumab should affect common signs of infection due to its immunosuppressive properties. Primary aim of the study was to investigate whether the administration of tocilizumab to critically ill patients with COVID-19, led to a different clinical presentation of infectious complications compared to patients who did not receive tocilizumab. Secondary aim was investigating differences in laboratory parameters between groups.

METHODS

Single-centre retrospective study, enrolling COVID-19 patients who developed a microbiologically confirmed infectious complication [ventilator associated pneumonia or bloodstream infection] after intensive care unit [ICU] admission and either treated with tocilizumab or not [controls].

RESULTS

A total of 58 patients were included, 25 treated with tocilizumab and 33 controls. Median time from tocilizumab administration to infection onset was 10 days [range 2-26]. Patients were 78% male, with median age 65 years [range 45-79]. At first clinical presentation of the infectious event, the frequency of hypotension [11/25, 44% vs. 11/33, 33%], fever [8/25, 32% vs. 10/33, 30%] or hypothermia [0/25,0%, vs. 2/33, 6%], and oxygen desaturation [6/25, 28% vs 4/33, 12%], as well as the frequency of SOFA score increase of ≥ 2 points [4/25, 16%,vs. 4/33, 12%] was similar in tocilizumab treated patients and controls [p>0.1 for all comparisons]. Among laboratory parameters, C-Reactive Protein elevation was reduced in tocilizumab treated patients compared to controls [8/25, 32% vs. 22/33, 67%, p=0.009].

CONCLUSION

The clinical features of infectious complications in critically ill patients with COVID-19 admitted to ICU were not affected by tocilizumab.

Factors Associated With Prolonged Antibiotic Use in the Setting of Suspected Pneumonia and Negative Bronchoalveolar Lavage Cultures

Background: Diagnostic criterion for pneumonia includes clinical data and bronchoalveolar lavage cultures (BALCx) to identify pathogens. Although ~60% of BALCx are negative, there may be reluctance to discontinue antibiotics, leading to prolonged antibiotic use (PAU). Objective: The purpose of this study is to compare outcomes of subjects with negative BALCx with PAU versus without prolonged antibiotic use (nPAU). Methods: A retrospective cohort study was conducted including subjects admitted to the intensive care unit (ICU), with suspected pneumonia, and negative BALCx. Data were compared based on length of exposure to antibiotics, PAU (antibiotics >4 days) versus nPAU (antibiotics <4 days). Results: A total of 128 subjects were included, 57 in the PAU group and 71 in the nPAU group. Baseline demographics were similar between groups. Severity of illness measured by multiple organ dysfunction scores at time of bronchoalveolar lavage (BAL) collection to final result showed a statistically significant decrease in the PAU group but not in the nPAU group. No differences were found in ICU days, ventilator-free days, or mortality; however, length of stay was longer for PAU (23 vs. 17, p = .04). In the PAU group, there were fewer BALCx results of "no growth" (23% vs. 45%, p = .04), more positive gram stains (83% vs. 60%, p = .01) and more positive non-BALCx (40% vs. 14%, p = .01). In a multivariate analysis, factors associated with PAU were positive BAL gram stains (adjusted odds ratio [aOR] 3.1, p = .037) and positive non-BALCx (aOR 4.7, p = .002). Conclusion: For subjects with suspected pneumonia and negative BALCx, positive non-BALCx and positive BALCx gram stain influenced the length of exposure of antibiotics.

Protocol for an international, multicentre, prospective, observational study of nosocomial pneumonia in intensive care units: the PneumoINSPIRE study

Background: Nosocomial pneumonia in the critical care setting is associated with increased morbidity, significant crude mortality rates and high health care costs. Ventilator-associated pneumonia represents about 80% of nosocomial pneumonia cases in intensive care units (ICUs). Wide variance in incidence of nosocomial pneumonia and diagnostic techniques used has been reported, while successful treatment remains complex and a matter of debate. Objective: To describe the epidemiology, diagnostic strategies and treatment modalities for nosocomial pneumonia in contemporary ICU settings across multiple countries around the world. Design, setting and patients: PneumoINSPIRE is a large, multinational, prospective cohort study of adult ICU patients diagnosed with nosocomial pneumonia. Participating ICUs from at least 20 countries will collect data on 10 or more consecutive ICU patients with nosocomial pneumonia. Site-specific information, including hospital policies on antibiotic therapy, will be recorded along with patient-specific data. Variables that will be explored include: aetiology and antimicrobial resistance patterns, treatment-related parameters (including time to initiation of antibiotic therapy, and empirical antibiotic choice, dose and escalation or de-escalation), pneumonia resolution, ICU and hospital mortality, and risk factors for unfavourable outcomes. The concordance of ventilator-associated pneumonia diagnosis with accepted definitions will also be assessed. Results and conclusions: PneumoINSPIRE will provide valuable information on current diagnostic and management practices relating to ICU nosocomial pneumonia, and identify research priorities in the field. Trial registration:ClinicalTrials.gov identifier NCT02793141.

Evaluation of semi-quantitative compared to quantitative cultures of tracheal aspirates for the yield of culturable respiratory pathogens - a cross-sectional study

Background

Diagnosis of lower respiratory tract infections (LRTI) depends on the presence of clinical, radiological and microbiological findings. Endotracheal suction aspirate (ETSA) is the commonest respiratory sample sent for culture from intubated patients. Very few studies have compared quantitative and semi-quantitative processing of ETSA cultures for LRTI diagnosis. We determined the diagnostic accuracy of quantitative and semi-quantitative ETSA culture for LRTI diagnosis, agreement between the quantitative and semi quantitative culture techniques and the yield of respiratory pathogens with both methods.

Methods

This was a cross-sectional study conducted at the Aga Khan University clinical laboratory, Karachi, Pakistan. One hundred and seventy-eight ETSA samples sent for routine bacteriological cultures were processed quantitatively as part of regular specimen processing method and semi-quantitatively. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy was calculated for both methods using clinical diagnosis of pneumonia as reference standard. Agreement between the quantitative and semi quantitative methods was assessed via the kappa statistic test. Pathogen yield between the two methods was compared using Pearson’s chi-square test.

Results

The quantitative and semi-quantitative methods yielded pathogens in 81 (45.5%) and 85 (47.8%) cases respectively. There was complete concordance of both techniques in 155 (87.1%) ETSA samples. No growth was observed in 45 (25.3%) ETSA specimens with quantitative culture and 37 (20.8%) cases by semi-quantitative culture. The diagnostic accuracy of both techniques were comparable; 64.6% for quantitative and 64.0% for semi-quantitative culture. The kappa agreement was found to be 0.84 (95% CI, 0.77–0.91) representing almost perfect agreement between the two methods. Although semi-quantitative cultures yielded more pathogens (47.8%) as compared to quantitative ETSA cultures (45.5%), the difference was only 2.3%. However, this difference achieved statistical (chi-square p-value < 0.001) favoring semi-quantitative culture methods over quantitative culture techniques for processing ETSA.

Conclusion

In conclusion, there is a strong agreement between the performances of both methods of processing ETSA cultures in terms of accuracy of LRTI diagnosis. Semi-quantitative cultures of ETSA yielded more pathogens as compared to quantitative cultures. Although both techniques were comparable, we recommend processing of ETSA using semi-quantitative technique due to its ease and reduced processing time.

Emergence of Alveolar Consolidations in Serial Lung Ultrasound and Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Lung ultrasound (LUS) has been reported as a promising diagnostic tool for ventilator-associated pneumonia (VAP), but patients with previous lung parenchyma commitment have been not studied.

PURPOSE

To evaluate whether the emergence of sonographic consolidations, rather than their presence, can improve the VAP diagnosis in a sample including patients with previous lung parenchyma diseases.

METHODS

Patients who completed 48 hours of mechanical ventilation were prospectively studied with daily LUS examinations. We checked the emergence of different consolidation types on the eve and on the day of a clinical suspicion of VAP. We elaborated an algorithm considering, sequentially, the emergence of (1) subpleural consolidations in anterior lung regions on the eve of suspicion; (2) lobar/sublobar consolidation in anterior lung regions on the day of suspicion; (3) lobar/sublobar consolidation with dynamic air bronchograms on the day of suspicion; and (4) any other lobar/sublobar consolidation on the day of suspicion in association with a positive Gram smear of endotracheal aspirate.

RESULTS

Of the 188 included patients, 60 were suspected and 33 confirmed VAP. The presence of sonographic consolidations at the clinical suspicion had no diagnostic value for VAP. The emergence of subpleural consolidations in anterior lung regions on the eve of suspicion had specificity of 95% (95% confidence interval [CI], 79%-99%). The emergence of lobar/sublobar consolidations in anterior lung regions on the day of suspicion had specificity of 100% (95% CI, 87%-100%). The emergence of lobar/sublobar consolidations with dynamic air bronchograms on the day of suspicion had specificity of 96% (95% CI, 81%-99%). Finally, the proposed algorithm had sensitivity of 63% (95% CI, 46%-77%) and specificity of 85% (95% CI, 67%-94%) for VAP.

CONCLUSIONS

The presence of sonographic consolidations was not accurate for VAP when patients with previous lung parenchyma commitment were included. However, serial LUS examinations detected the emergence of specific signs of VAP.

The association of cardiovascular failure with treatment for ventilator-associated lower respiratory tract infection

PURPOSE

Ventilator associated-lower respiratory tract infections (VA-LRTIs), either ventilator-associated pneumonia (VAP) or tracheobronchitis (VAT), accounts for most nosocomial infections in intensive care units (ICU) including. Our aim was to determine if appropriate antibiotic treatment in patients with VA-LRTI will effectively reduce mortality in patients who had cardiovascular failure.

METHODS

This was a pre-planned subanalysis of a large prospective cohort of mechanically ventilated patients for at least 48 h in eight countries in two continents. Patients with a modified Sequential Organ Failure Assessment (mSOFA) cardiovascular score of 4 (at the time of VA-LRTI diagnosis and needed be present for at least 12 h) were defined as having cardiovascular failure.

RESULTS

VA-LRTI occurred in 689 (23.2%) out of 2960 patients and 174 (25.3%) developed cardiovascular failure. Patients with cardiovascular failure had significantly higher ICU mortality than those without (58% vs. 26.8%; p < 0.001; OR 3.7; 95% CI 2.6-5.4). A propensity score analysis found that the presence of inappropriate antibiotic treatment was an independent risk factor for ICU mortality in patients without cardiovascular failure, but not in those with cardiovascular failure. When the propensity score analysis was conducted in patients with VA-LRTI, the use of appropriate antibiotic treatment conferred a survival benefit for patients without cardiovascular failure who had only VAP.

CONCLUSIONS

Patients with VA-LRTI and cardiovascular failure did not show an association to a higher ICU survival with appropriate antibiotic treatment. Additionally, we found that in patients without cardiovascular failure, appropriate antibiotic treatment conferred a survival benefit for patients only with VAP.

TRIAL REGISTRY

ClinicalTrials.gov, number NCT01791530.

Does oral care with chlorhexidine reduce ventilator-associated pneumonia in mechanically ventilated adults?

Oral colonisation by pathogens contributes to contracting ventilator-associated pneumonia (VAP). The aim of this review was to determine whether the use of the antiseptic chlorhexidine in the intra-oral cavity reduced its incidence in the critically ill, mechanically ventilated adult. The findings from this review led to the conclusion that chlorhexidine reduced the occurrence of VAP. Although a recommendation to implement the use of intra-oral chlorhexidine for mechanically-ventilated patients within critical care can be made, further exploration into required frequency and method of administration would be beneficial to reduce unnecessary exposure and hinder pathogenic resistance.

Validation of a Host Response Assay, SeptiCyte LAB, for Discriminating Sepsis from Systemic Inflammatory Response Syndrome in the ICU

RATIONALE

A molecular test to distinguish between sepsis and systemic inflammation of noninfectious etiology could potentially have clinical utility.

OBJECTIVES

This study evaluated the diagnostic performance of a molecular host response assay (SeptiCyte LAB) designed to distinguish between sepsis and noninfectious systemic inflammation in critically ill adults.

METHODS

The study employed a prospective, observational, noninterventional design and recruited a heterogeneous cohort of adult critical care patients from seven sites in the United States (n = 249). An additional group of 198 patients, recruited in the large MARS (Molecular Diagnosis and Risk Stratification of Sepsis) consortium trial in the Netherlands ( www.clinicaltrials.gov identifier NCT01905033), was also tested and analyzed, making a grand total of 447 patients in our study. The performance of SeptiCyte LAB was compared with retrospective physician diagnosis by a panel of three experts.

MEASUREMENTS AND MAIN RESULTS

In receiver operating characteristic curve analysis, SeptiCyte LAB had an estimated area under the curve of 0.82-0.89 for discriminating sepsis from noninfectious systemic inflammation. The relative likelihood of sepsis versus noninfectious systemic inflammation was found to increase with increasing test score (range, 0-10). In a forward logistic regression analysis, the diagnostic performance of the assay was improved only marginally when used in combination with other clinical and laboratory variables, including procalcitonin. The performance of the assay was not significantly affected by demographic variables, including age, sex, or race/ethnicity.

CONCLUSIONS

SeptiCyte LAB appears to be a promising diagnostic tool to complement physician assessment of infection likelihood in critically ill adult patients with systemic inflammation. Clinical trial registered with www.clinicaltrials.gov (NCT01905033 and NCT02127502).

When not to start antibiotics: avoiding antibiotic overuse in the intensive care unit

BACKGROUND

Most intensive care unit (ICU) patients receive broad-spectrum antibiotics. While lifesaving in some, in others these treatments may be unnecessary and place patients at risk of antibiotic-associated harms.

OBJECTIVES

To review the literature exploring how we diagnose infection in patients in the ICU and address the safety and utility of a 'watchful waiting' approach to antibiotic initiation with selected patients in the ICU.

SOURCES

A semi-structured search of PubMed and Cochrane Library databases for articles published in English during the past 15 years was conducted.

CONTENT

Distinguishing infection from non-infectious mimics in ICU patients is uniquely challenging. At present, we do not have access to a rapid point-of-care test that reliably differentiates between individuals who need antibiotics and those who do not. A small number of studies have attempted to compare early aggressive versus conservative antimicrobial strategies in the ICU. However, this body of literature is small and not robust enough to guide practice.

IMPLICATIONS

This issue will not likely be resolved until there are diagnostic tests that rapidly and reliably identify the presence or absence of infection in the ICU population. In the meantime, prospective trials that identify clinical situations wherein it is safe to delay or withhold antibiotic initiation in the ICU until the presence of an infection is proven are warranted.

Antibiotic Distribution into Cerebrospinal Fluid: Can Dosing Safely Account for Drug and Disease Factors in the Treatment of Ventriculostomy-Associated Infections?

Ventriculostomy-associated infections, or ventriculitis, in critically ill patients are associated with considerable morbidity. Efficacious antibiotic dosing for the treatment of these infections may be complicated by altered antibiotic concentrations in the cerebrospinal fluid due to variable meningeal inflammation and antibiotic properties. Therefore, doses used to treat infections with a higher degree of meningeal inflammation (such as meningitis) may often fail to achieve equivalent exposures in patients with ventriculostomy-associated infections such as ventriculitis. This paper aims to review the disease burden, infection rates, and common pathogens associated with ventriculostomy-associated infections. This review also seeks to describe the disease- and drug-related factors that influence antibiotic distribution into cerebrospinal fluid and provide a critical appraisal of current dosing of antibiotics commonly used to treat these types of infections. A Medline search of relevant articles was conducted and used to support a review of cerebrospinal fluid penetration of vancomycin, including critical appraisal of the recent paper by Beach et al. recently published in this journal. We found that in the intensive care unit, ventriculostomy-associated infections are the most common and serious complication of external ventricular drain insertion and often result in prolonged patient stay and increased healthcare costs. Reported infection rates are extremely variable (between 0 and 45%), hindered by the inherent diagnostic difficulty. Both Gram-positive and Gram-negative organisms are associated with such infections and the rise of multi-drug-resistant pathogens means that effective treatment is an ongoing challenge. Disease factors that may need to be considered are reduced meningeal inflammation and the presence of critical illness; drug factors include physiochemical properties, degree of plasma-protein binding, and affinity to active transporter proteins present in the blood-cerebrospinal fluid barrier. The relationship between cerebrospinal fluid antibiotic exposures in the setting of ventriculostomy-associated infection and clinical response has not been fully elucidated for many of the antibiotics commonly used in its treatment. More thorough and clinically relevant investigations are needed to better define blood pharmacokinetic/pharmacodynamics targets and optimal therapeutic exposures for treatment of ventriculostomy-associated infections. It is hoped that this future research will be able to provide clearer recommendations for clinicians frequently faced with dosing-related dilemmas when treating patients with these challenging infections.

How Can We Distinguish Ventilator-Associated Tracheobronchitis from Pneumonia?

Ventilator-associated tracheobronchitis (VAT) might represent an intermediate process between lower respiratory tract colonization and ventilator-associated pneumonia (VAP), or even a less severe spectrum of VAP. There is an urgent need for new concepts in the arena of ventilator-associated lower respiratory tract infections. Ideally, the gold standard of care is based on prevention rather than treatment of respiratory infection. However, despite numerous and sometimes imaginative efforts to validate the benefit of these measures, most clinicians now accept that currently available measures have failed to eradicate VAP. Stopping the progression from VAT to VAP could improve patient outcomes.

Exhaled breath metabolomics reveals a pathogen-specific response in a rat pneumonia model for two human pathogenic bacteria: a proof-of-concept study

Volatile organic compounds in breath can reflect host and pathogen metabolism and might be used to diagnose pneumonia. We hypothesized that rats with Streptococcus pneumoniae ( SP) or Pseudomonas aeruginosa ( PA) pneumonia can be discriminated from uninfected controls by thermal desorption-gas chromatography-mass-spectrometry (TD-GC-MS) and selected ion flow tube-mass spectrometry (SIFT-MS) of exhaled breath. Male adult rats ( n = 50) received an intratracheal inoculation of 1) 200 µl saline, or 2) 1 × 107 colony-forming units of SP or 3) 1 × 107 CFU of PA. Twenty-four hours later the rats were anaesthetized, tracheotomized, and mechanically ventilated. Exhaled breath was analyzed via TD-GC-MS and SIFT-MS. Area under the receiver operating characteristic curves (AUROCCs) and correct classification rate (CCRs) were calculated after leave-one-out cross-validation of sparse partial least squares-discriminant analysis. Analysis of GC-MS data showed an AUROCC (95% confidence interval) of 0.85 (0.73–0.96) and CCR of 94.6% for infected versus noninfected animals, AUROCC of 0.98 (0.94–1) and CCR of 99.9% for SP versus PA, 0.92 (0.83–1.00), CCR of 98.1% for SP versus controls and 0.97 (0.92–1.00), and CCR of 99.9% for PA versus controls. For these comparisons the SIFT-MS data showed AUROCCs of 0.54, 0.89, 0.63, and 0.79, respectively. Exhaled breath analysis discriminated between respiratory infection and no infection but with even better accuracy between specific pathogens. Future clinical studies should not only focus on the presence of respiratory infection but also on the discrimination between specific pathogens.

Drug Prevention and Control of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is one of the most prevalent and serious complications of mechanical ventilation, which is considered a common nosocomial infection in critically ill patients. There are some great options for the prevention of VAP: (i) minimize ventilator exposure; (ii) intensive oral care; (iii) aspiration of subglottic secretions; (iv) maintain optimal positioning and encourage mobility; and (v) prophylactic probiotics. Furthermore, clinical management of VAP depends on appropriate antimicrobial therapy, which needs to be selected based on individual patient factors, such as previous antibacterial therapy, history of hospitalization or mechanical ventilation, and bacterial pathogens and antibiotic resistance patterns. In fact, antibiotic resistance has exponentially increased over the last decade, and the isolation of a multidrug-resistant (MDR) pathogen has been identified as an independent predictor of inadequate initial antibiotic therapy and which is significantly associated with increased mortality. Multiple attempts were used in the treatment of VAP, such as novel antibacterial agents, inhaled antibiotics and monoclonal antibodies. In this review, we summarize the current therapeutic options for the prevention and treatment of VAP, aiming to better management of VAP in clinical practice.

Variations of the lung microbiome and immune response in mechanically ventilated surgical patients

Mechanically ventilated surgical patients have a variety of bacterial flora that are often undetectable by traditional culture methods. The source of infection in many of these patients remains unclear. To address this clinical problem, the microbiome profile and host inflammatory response in bronchoalveolar lavage samples from the surgical intensive care unit were examined relative to clinical pathology diagnoses. The hypothesis was tested that clinical diagnosis of respiratory tract flora were similar to culture positive lavage samples in both microbiome and inflammatory profile. Bronchoalveolar lavage samples were collected in the surgical intensive care unit as standard of care for intubated individuals with a clinical pulmonary infection score of >6 or who were expected to be intubated for >48 hours. Cytokine analysis was conducted with the Bioplex Pro Human Th17 cytokine panel. The microbiome of the samples was sequenced for the 16S rRNA region using the Ion Torrent. Microbiome diversity analysis showed the culture-positive samples had the lowest levels of diversity and culture negative with the highest based upon the Shannon-Wiener index (culture positive: 0.77 ± 0.36, respiratory tract flora: 2.06 ± 0.73, culture negative: 3.97 ± 0.65). Culture-negative samples were not dominated by a single bacterial genera. Lavages classified as respiratory tract flora were more similar to the culture-positive in the microbiome profile. A comparison of cytokine expression between groups showed increased levels of cytokines (IFN-g, IL-17F, IL-1B, IL-31, TNF-a) in culture-positive and respiratory tract flora groups. Culture-positive samples exhibited a more robust immune response and reduced diversity of bacterial genera. Lower cytokine levels in culture-negative samples, despite a greater number of bacterial species, suggest a resident nonpathogenic bacterial community may be indicative of a normal pulmonary environment. Respiratory tract flora samples were most similar to the culture-positive samples and may warrant classification as culture-positive when considering clinical treatment.

Multimodality respiratory physiotherapy reduces mortality but may not prevent ventilator-associated pneumonia or reduce length of stay in the intensive care unit: a systematic review

QUESTION

In intubated adult patients receiving mechanical ventilation, does multimodality respiratory physiotherapy prevent ventilator-associated pneumonia, shorten length of intensive care unit (ICU) stay, and reduce mortality?

DESIGN

A systematic review with meta-analysis of randomised controlled trials.

PARTICIPANTS

Intubated adult patients undergoing mechanical ventilation who were admitted to an intensive care unit.

INTERVENTION

More than two respiratory physiotherapy techniques such as positioning or postural drainage, manual hyperinflation, vibration, rib springing, and suctioning.

OUTCOMES MEASURES

Incidence of ventilator-associated pneumonia (VAP), duration of ICU stay, and mortality.

RESULTS

Five trials were included in the meta-analysis. Random-effects models were used to calculate pooled weighted mean difference (WMD) for length of ICU stay and pooled risk ratio (RR) for incidence of VAP, and fixed-effects model was used to calculate pooled RR for mortality. The effect on the incidence of VAP was unclear (RR 0.73 in favour of multimodality respiratory physiotherapy, 95% CI 0.38 to 1.07). The effect on length of stay was also unclear (WMD -0.33days shorter with multimodality respiratory physiotherapy, 95% CI -2.31 to 1.66). However, multimodality respiratory physiotherapy significantly reduced mortality (RR 0.75, 95% CI 0.58 to 0.92).

CONCLUSION

Multimodality respiratory physiotherapy appeared to reduce mortality in ICU patients. It was unclear whether this occurred via a reduction in the incidence of VAP and/or length of stay because the available data provided very imprecise estimates of the effect of multimodality respiratory physiotherapy on these outcomes. These very imprecise estimates include the possibility of very worthwhile effects on VAP incidence and length of ICU stay; therefore, these outcomes should be the focus of further investigation in rigorous trials.

REGISTRATION

PROSPERO CRD42018094202. [Pozuelo-Carrascosa DP, Torres-Costoso A, Alvarez-Bueno C, Cavero-Redondo I, López Muñoz P, Martínez-Vizcaíno V (2018) Multimodality respiratory physiotherapy reduces mortality but may not prevent ventilator-associated pneumonia or reduce length of stay in the intensive care unit: a systematic review. Journal of Physiotherapy 64: 222-228].

Pneumonia

Neonatal pneumonia may occur in isolation or as one component of a larger infectious process. Bacteria, viruses, fungi, and parasites are all potential causes of neonatal pneumonia, and may be transmitted vertically from the mother or acquired from the postnatal environment. The patient's age at the time of disease onset may help narrow the differential diagnosis, as different pathogens are associated with congenital, early-onset, and late-onset pneumonia. Supportive care and rationally selected antimicrobial therapy are the mainstays of treatment for neonatal pneumonia. The challenges involved in microbiological testing of the lower airways may prevent definitive identification of a causative organism. In this case, secondary data must guide selection of empiric therapy, and the response to treatment must be closely monitored.

[Description and role of bacteriological techniques in the management of lung infections]

Les pneumopathies aiguës recouvrent des contextes cliniques variés et les étiologies bactériennes impliquées le sont tout autant. Aucun outil microbiologique n’est 100 % sensible ni 100 % spécifique et malgré les investigations, plus de 30 % des pneumopathies restent sans étiologie identifiée. Si aucun prélèvement n’est indiqué pour les patients traités en ambulatoire, les prélèvements respiratoires non invasifs sont à privilégier pour les pneumopathies aiguës hospitalisées (communautaires ou associées aux soins), tandis que les prélèvements invasifs sont indiqués en seconde ligne pour les pneumopathies aiguës communautaires en réanimation, et en première ligne pour les pneumopathies aiguës de l’immunodéprimé. La culture microbiologique garde une place importante, à condition que le malade soit prélevé avant instauration de l’antibiothérapie. Certains contextes peuvent justifier le recours aux hémocultures, à la recherche d’antigènes urinaires ou aux sérologies. Les PCR rendent déjà service au quotidien mais l’avenir à court terme appartient probablement aux panels moléculaires multiplex capables de détecter de nombreux micro-organismes en quelques heures, surtout dans les pneumopathies communautaires sévères de réanimation et les pneumopathies aiguës de l’immunodéprimé. Le séquençage nucléotidique haut débit révolutionnera bientôt le diagnostic microbiologique, en pneumologie comme dans les autres domaines de l’infectiologie.

Low Efficacy of Antibiotics Against Staphylococcus aureus Airway Colonization in Ventilated Patients

Background

Airway-colonization by Staphylococcus aureus predisposes to the development of ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). Despite extensive antibiotic treatment of intensive care unit patients, limited data are available on the efficacy of antibiotics on bacterial airway colonization and/or prevention of infections. Therefore, microbiologic responses to antibiotic treatment were evaluated in ventilated patients.

Methods

Results of semiquantitative analyses of S. aureus burden in serial endotracheal-aspirate (ETA) samples and VAT/VAP diagnosis were correlated to antibiotic treatment. Minimum inhibitory concentrations of relevant antibiotics using serially collected isolates were evaluated.

Results

Forty-eight mechanically ventilated patients who were S. aureus positive by ETA samples and treated with relevant antibiotics for at least 2 consecutive days were included in the study. Vancomycin failed to reduce methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) burden in the airways. Oxacillin was ineffective for MSSA colonization in approximately 30% of the patients, and responders were typically coadministered additional antibiotics. Despite antibiotic exposure, 15 of the 39 patients (approximately 38%) colonized only by S. aureus and treated with appropriate antibiotic for at least 2 days still progressed to VAP. Importantly, no change in antibiotic susceptibility of S. aureus isolates was observed during treatment. Staphylococcus aureus colonization levels inversely correlated with the presence of normal respiratory flora.

Conclusions

Antibiotic treatment is ineffective in reducing S. aureus colonization in the lower airways and preventing VAT or VAP. Staphylococcus aureus is in competition for colonization with the normal respiratory flora. To improve patient outcomes, alternatives to antibiotics are urgently needed.

Aerosolized tobramycin for Pseudomonas aeruginosa ventilator-associated pneumonia in patients with acute respiratory distress syndrome

BACKGROUND

Ventilator-associated pneumonia (VAP) due to Pseudomonas aeruginosa has a high mortality and recurrence rate, especially in patients with acute respiratory distress syndrome (ARDS). Therefore, new therapeutic strategies against severe pneumonia are needed. This study evaluated the efficacy of aerosolized tobramycin for P. aeruginosa VAP in ARDS patients.

METHODS

A retrospective analysis was performed on patients who developed VAP caused by P. aeruginosa during the course of ARDS at the intensive care unit (ICU) of Kumamoto University Hospital. Aerosolized tobramycin inhalation solution (TIS) 240 mg was administered daily for 14 days in addition to systemic antibiotics.

RESULTS

A total of 44 patients (TIS group, n = 22; control group, n = 22) were included in the analysis. No significant differences were found between the two groups in terms of clinical characteristics, including acute physiology and chronic health evaluation II score upon ICU admission. The TIS group had significantly lower recurrence of P. aeruginosa VAP (22.7% vs. 52.4%, P = 0.04) and ICU mortality (22.7% vs. 63.6%, P < 0.01) than the control group. Bacterial concentration in tracheal aspirate (mean log 10 cfu/mL ± SD on days 2-5: 1.2 ± 1.3 vs. 5.0 ± 2.3, P < 0.01) decreased more rapidly and markedly in the TIS group compared with the control group.

CONCLUSION

Aerosolized tobramycin was an effective therapeutic strategy for P. aeruginosa VAP patients with ARDS.

Individualized antibiotic therapy in patients with ventilator-associated pneumonia

The optimal duration of the treatment of ventilator-associated pneumonia (VAP) is still the subject of debate. While 1 week treatment has been reported as possibly sufficient, patients generally receive antibiotic therapy for 10 to 14 days. The purpose of our study was to investigate whether length of treatment in patients with VAP can be reduced with an individualized therapeutic strategy. The study was performed prospectively with patients diagnosed with VAP in our hospital's intensive care units between 1 January and 31 December 2015. Duration of antibiotic therapy was determined with 5 day clinical evaluation according to previously established criteria. Patients were divided into two groups depending on length of treatment, short (7-10 days) and long treatment (>10 days). Nineteen patients received 7 to 10 day antibiotic therapy, and 30 received >10 day antibiotic therapy. Demographic and clinical characteristics, Glasgow Coma Scale score, CPIS and the PaO2/FiO2 ratio at the time of diagnosis of VAP were statistically similar between the two groups (P>0.05). A second VAP attack occurred post-treatment in three patients receiving short-term treatment and in four receiving long-term treatment (P=0.561). The numbers of antibiotic-free days were 15.6±6.2 in the short-term treatment group and 8.3±7.5 in the long-term group (P<0.0001). One of the patients receiving short-term treatment died within 28 days after treatment, and four of the patients receiving long-term treatment (P=0.348) did so. The most commonly observed micro-organisms in both groups were Acinetobacterbaumannii and Pseudomonasaeruginosa. Short-term treatment can be administered in cases with early clinical and laboratory response started on VAP treatment by considering individual characteristics and monitoring fever, CPIS, the PaO2/FiO2 ratio, C-reactive protein and procalcitonin values.

New parameters for childhood ventilator associated pneumonia diagnosis

PURPOSE

Our aim is to determine whether the presence of soluble triggering receptor expressed on myeloid cells-1 (s-TREM-1) of bronchoalveolar lavage fluid (BALF), serum procalcitonin levels (PCT), and Clinical Pulmonary Infection Score (CPIS) have diagnostic value in children with VAP.

METHODS

All children followed in pediatric intensive care unit (PICU) who were mechanically ventilated at least for 48 hr between January 2014 and December 2015 were enrolled into our study. BALF sample was obtained via non-bronchoscopic method from the children with VAP suspicion (case group) and s-TREM-1 levels were measured. Furthermore we calculated CPIS and measured serum PCT levels. Same procedures were applied to the control group who were admitted to PICU without infectious problems and who were not under antimicrobial therapy. First we compared the case group with the control group and then we compared the quantitative culture confirmed and non-confirmed VAP cases among themselves.

RESULTS

Case group (n:58) had significant higher PCT and s-TREM-1 levels compared to control group (n:58). The VAP confirmed cases had higher s-TREM-1, PCT ve CPIS levels compared to non-confirmed VAP cases. s-TREM-1, PCT ve CPIS variables were found to be independent risk factors for VAP. The cutoff values for s-TREM-1, CPIS, and PCT, are 281 pg/ml, 6, and 1.9 ng/ml, respectively. The patients whose s-TREM-1, CPIS, and PCT values above the cutoff levels were found to have higher cumulative VAP rate.

CONCLUSIONS

s-TREM-1 of BALF, serum PCT levels, and CPIS are useful predictors for ventilator-associated pneumonia diagnosis in children. Pediatr Pulmonol. 2017;52:119-128. © 2016 Wiley Periodicals, Inc.

Clinical effects of Bifidobacterium triple viable tablets combined with montmorillonite in treatment of damp-heat diarrhea in children

AIM

To evaluate the clinical effects of Bifidobacterium triple viable tablets combined with montmorillonite in the treatment of damp-heat diarrhea in children and to explore the mechanism involved.

METHODS

Sixty pediatric patients with damp-heat diarrhea were randomly divided into either a control group (n = 30) or an observation group (n = 30). The control group was treated with montmorillonite alone, and the observation group was treated with Bifidobacterium triple viable tablets plus montmorillonite. Clinical efficacy was compared between the two groups. The possible immune mechanism involved was explored by detecting different subsets of T cells. The rate of adverse drug reactions was also compared between the two groups.

RESULTS

The times to recovery of normal body temperature, normal stool, and remission of vomiting and abdominal pain were significantly shorter in the observation group than in the control group (P < 0.05). Before treatment, there were no significant differences in CD3⁺ cells, CD4⁺ cells, or CD4⁺/CD8⁺ ratio between the two groups (P > 0.05); however, these indexes were significantly higher in the observation group than in the control group 5 d after treatment (P < 0.05). The rate of adverse drug reactions between the two groups had no statistical significance (P > 0.05).

CONCLUSION

Bifidobacterium triple viable tablets combined with montmorillonite is more effective than montmorillonite alone in children with damp-heat diarrhea, and it can regulate the body's immunity.

Treatment of infants with bacterial pneumonia and diarrhea: Clinical efficacy and impact on immune cells

AIM

To evaluate the efficacy of different treatments in infants with bacterial pneumonia and diarrhea and their impact on immune cells.

METHODS

From January 2015 to July 2016, 60 infants with bacterial pneumonia and diarrhea treated at our hospital were divided into either a control group (n = 30) or an observation group (n = 30). The control group was treated with lactobacillus tablets, and the observation group was treated with lactobacillus tablets combined with Smecta. Flow cytometry was used to determine immune indexes. Clinical efficacy and immunity were compared between the two groups.

RESULTS

After 7 d of treatment, the effective rate was significantly higher in the observation group than in the control group (93.33% vs 70.00%, P < 0.05). Times to recovery of normal stool frequency, normal stool characters, normal laboratory values, and disappearance of clinical symptoms were significantly shorter in the observation group than in the control group (P < 0.05). The levels of IgM, IgG and IgA were significantly higher in the observation group than in the control group (P < 0.05).

CONCLUSION

For infants with bacterial pneumonia complicated by diarrhea, lactobacillus tablets combined with Smecta can improve the immune levels and have good efficacy.

Microfloral diversity in the lower respiratory tracts of neonates with bacterial infectious pneumonia combined with ventilator‑associated pneumonia

Bacterial infectious pneumonia is one of the major causes of mortality in neonates, particularly when the neonates suffer from ventilator‑associated pneumonia (VAP). However, the causes of pneumonia are difficult to define. Thus, the present study focused on understanding the diversity of microflora in the lower respiratory tract to elucidate the causes. The experimental groups comprised newborns who suffered from infectious pneumonia with or without VAP (IVAP and IP groups, respectively), whereas the control group comprised newborns who suffered from respiratory distress syndrome (RDS) without VAP (RDS group). Following 1, 3 and 5 days of ventilation, sputum samples were collected and the DNA was extracted. The DNA was amplified and separated, and the 16S rDNA was then sequenced and analyzed for diversity. The results of the diversity and Shannon‑Wiener indices were ordered as follows: IVAP group < IP group < RDS group. The percentages of Streptococcus sp., Serratia sp. and Achromobacter sp. in the IP and IVAP groups were higher, compared with those in the RDS group, whereas the percentages of Klebsiella sp. and Acinetobacter sp. were lower on day 1. The percentages of Klebsiella sp. and Streptococcus sp. on days 1 and 3 were ordered as follows: IVAP group > IP group > RDS group, and the percentages of Serratia sp., Acinetobacter sp. and Achromobacter sp. were ordered as follows: IVAP group < IP group < RDS group. After 3‑5 days, the percentages of Klebsiella sp., Acinetobacter sp., Streptococcus sp., Serratia sp. and Achromobacter sp. in the IVAP group were lower, compared with those in the RDS and IP groups. It was concluded that the decreased microfloral diversity, increased constituent ratios of Klebsiella sp. and Streptococcus sp., and decreased ratios of Serratia sp. and Acinetobacter sp. in the lower respiratory tract of neonates suffering from pneumonia may be indicators of VAP.

Preventing Ventilator-Associated Infections

Mechanical ventilator use is fraught with risk of complications. Ventilator-associated pneumonia (VAP) is a common complication that prolongs stays on the ventilator and increases mortality and costs. The Centers for Disease Control and Prevention recommend the use of the term, ventilator-associated event. Prevention and/or interruption of cycle of inflammation, colonization of respiratory tract, and ventilator-associated tracheobronchitis are key to managing VAP. Modifying risk factors using a ventilator bundle is considered standard of care. The contentious factors and the lack of support for early tracheotomy, parenteral nutrition, and monitoring of gastric residuals are also addressed. Finally, the role of ventilator-associated tracheobronchitis in VAP is discussed.

Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.These guidelines are intended for use by healthcare professionals who care for patients at risk for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), including specialists in infectious diseases, pulmonary diseases, critical care, and surgeons, anesthesiologists, hospitalists, and any clinicians and healthcare providers caring for hospitalized patients with nosocomial pneumonia. The panel's recommendations for the diagnosis and treatment of HAP and VAP are based upon evidence derived from topic-specific systematic literature reviews.

Differentiating infectious and noninfectious ventilator-associated complications: A new challenge

BACKGROUND

The purpose of this study was to develop an electronic search algorithm which reliably differentiates infectious and noninfectious ventilator-associated events (VAEs). This was a retrospective cohort study used to derive a predictive model. It took place at a tertiary care hospital campus.

METHODS

Participants included all ventilated patients who met the Centers for Disease Control and Prevention's National Health Safety Network definitions for VAEs between January 1, 2012, and December 31, 2013. There were 164 patients who experienced 185 VAEs in the study period.

RESULTS

The most predictive variables were fever 2 days before VAE onset, oxygenation changes, and appearance of respiratory secretions. No other variable, including laboratory tests, radiologic findings, and vital sign values, reached statistical significance. A multivariate regression model was constructed, with 68% sensitivity and 75% specificity (receiver operator characteristic area under the curve [ROC-AUC], 0.83). This was modestly better than the clinical pulmonary infection score (CPIS), which had sensitivity of 50%, specificity of 59%, and ROC-AUC of 0.60.

CONCLUSIONS

Although diagnosis of VAEs remains challenging, our data indicate that clinical signs and symptoms of a VAE may be present up to 2 days before they screen positive. Sputum, fever, and oxygenation requirements all were indicative, but aggregate models failed to create a sensitive and specific model for differentiation of VAEs. The existing clinical tool, the CPIS, is also insufficiently sensitive and specific. Further research is needed to create a clinically viable tool for differentiating VAE types at the bedside.

Two-color widefield fluorescence microendoscopy enables multiplexed molecular imaging in the alveolar space of human lung tissue

We demonstrate a fast two-color widefield fluorescence microendoscopy system capable of simultaneously detecting several disease targets in intact human ex vivo lung tissue. We characterize the system for light throughput from the excitation light emitting diodes, fluorescence collection efficiency, and chromatic focal shifts. We demonstrate the effectiveness of the instrument by imaging bacteria (Pseudomonas aeruginosa) in ex vivo human lung tissue. We describe a mechanism of bacterial detection through the fiber bundle that uses blinking effects of bacteria as they move in front of the fiber core providing detection of objects smaller than the fiber core and cladding (∼3  μm ∼3  μm ). This effectively increases the measured spatial resolution of 4  μm 4  μm . We show simultaneous imaging of neutrophils, monocytes, and fungus (Aspergillus fumigatus) in ex vivo human lung tissue. The instrument has 10 nM and 50 nM sensitivity for fluorescein and Cy5 solutions, respectively. Lung tissue autofluorescence remains visible at up to 200 fps camera acquisition rate. The optical system lends itself to clinical translation due to high-fluorescence sensitivity, simplicity, and the ability to multiplex several pathological molecular imaging targets simultaneously.

Ventilator-Associated Pneumonia in Trauma Patients: Different Criteria, Different Rates

BACKGROUND

No consensus exists regarding the definition of ventilator-associated pneumonia (VAP). Even within a single institution, inconsistent diagnostic criteria result in conflicting rates of VAP. As a Level 1 trauma center participating in the Trauma Quality Improvement Project (TQIP) and the National Healthcare Safety Network (NHSN), our institution showed inconsistencies in VAP rates depending on which criteria was applied. The purpose of this study was to compare VAP definitions, defined by culture-based criteria, National Trauma Data Bank (NTDB) and NHSN, using incidence in trauma patients.

METHODS

A retrospective chart review of consecutive trauma patients who were diagnosed with VAP and met pre-determined inclusion and exclusion criteria admitted to our rural, 861-bed, Level 1 trauma and tertiary care center between January 2008 and December 2011 was performed. These patients were identified from the National Trauma Registry of the American College of Surgeons (NTRACS) database and an in-house infection control database. Ventilator-associated pneumonia diagnosis criteria defined by the U.S. Center for Disease Control and Prevention (used by the NHSN), the NTDB, and our institutional, culture-based criteria gold standard were compared among patients.

RESULTS

Two hundred seventy-nine patients were diagnosed with VAP (25.4% met NHSN criteria, 88.2% met NTDB, and 76.3% met culture-based criteria). Only 58 (20.1%) patients met all three criteria. When NHSN criteria were compared with culture-based criteria, NHSN showed a high specificity (92.5%) and low sensitivity (28.2%). The positive predictive value (PPV) was 84.5%, but the negative predictive value (NPV) was 47.1%. The agreement between the NHSN and the culture-based criteria was poor (κ = 0.18). Conversely, the NTDB showed a lower specificity (57.8%), but greater sensitivity (86.4%) compared with culture-based criteria. The PPV and NPV were both 74% and the two criteria showed fair agreement (κ = 0.41).

CONCLUSIONS

The lack of standard diagnostic criteria for VAP resulted in variable reporting to different agencies. Emphasis on establishing a consensus VAP definition should be undertaken.

Device-associated pneumonia of very low birth weight infants in Polish Neonatal Intensive Care Units

PURPOSE

Late-Onset Pneumonia (LO-PNEU) is still the most important complication associated with the hospitalization of infants with very low birth weight (<1501g). The purpose of this paper is to summarize the results of an ongoing surveillance program defining LO-PNEU as associated or not associated with respiratory support in the NICU and distribution of causative pathogens from the Polish Neonatology Surveillance Network (PNSN).

MATERIALS AND METHODS

Surveillance of infections was conducted in the years 2009-2011 at six Polish NICUs.

RESULTS

The incidence was 3.1/1000 NICU patient days (pds). The mean gestational age and birth weight among infants with LO-PNEU were significantly lower. The VAP incidence was of 18.2/1000 NICU pds for mechanically ventilated (MV) infants, while the rates for those receiving only CPAP were as low as 7.7/1000 NICU pds. MV significantly increased the risk of PNEU, but MV or CPAP for <10 days did not increase the risk of LO-PNEU. Significantly associated with LO-PNEU was the use of central or peripheral venous catheters and total parenteral nutrition for longer periods. Microorganisms isolated in cases of LO-PNEU were Gram-positive cocci (53.5%) and Gram-negative rods, with predominating E. coli. Non fermentative bacilli were significantly more frequent in cases of VAP than in other cases.

CONCLUSIONS

Observed incidence rates associated with VAP and CPAP-PNEU, were higher than in other national surveillance systems and expressing the feasibility of lowering the risk of LO-PNEU and increasing patient safety. The incidence of pneumonia was found to be lower when using CPAP as compared to using MV.

Incidence of ventilator-associated pneumonia in Australasian intensive care units: use of a consensus-developed clinical surveillance checklist in a multisite prospective audit

OBJECTIVES

With disagreements on diagnostic criteria for ventilator-associated pneumonia (VAP) hampering efforts to monitor incidence and implement preventative strategies, the study objectives were to develop a checklist for clinical surveillance of VAP, and conduct an audit in Australian/New Zealand intensive care units (ICUs) using the checklist.

SETTING

Online survey software was used for checklist development. The prospective audit using the checklist was conducted in 10 ICUs in Australia and New Zealand.

PARTICIPANTS

Checklist development was conducted with members of a bi-national professional society for critical care physicians using a modified Delphi technique and survey. A 30-day audit of adult patients mechanically ventilated for >72 h.

PRIMARY AND SECONDARY OUTCOME MEASURES

Presence of items on the screening checklist; physician diagnosis of VAP, clinical characteristics, investigations, treatments and patient outcome.

RESULTS

A VAP checklist was developed with five items: decreasing gas exchange, sputum changes, chest X-ray infiltrates, inflammatory response, microbial growth. Of the 169 participants, 17% (n=29) demonstrated characteristics of VAP using the checklist. A similar proportion had an independent physician diagnosis (n=30), but in a different patient subset (only 17% of cases were identified by both methods). The VAP rate per 1000 mechanical ventilator days for the checklist and clinician diagnosis was 25.9 and 26.7, respectively. The item 'inflammatory response' was most associated with the first episode of physician-diagnosed VAP.

CONCLUSIONS

VAP rates using the checklist and physician diagnosis were similar to ranges reported internationally and in Australia. Of note, different patients were identified with VAP by the checklist and physicians. While the checklist items may assist in identifying patients at risk of developing VAP, and demonstrates synergy with the recently developed Centers for Disease Control (CDC) guidelines, decision-making processes by physicians when diagnosing VAP requires further exploration.

Ventilator-associated Pneumonia caused by commensal oropharyngeal Flora; [corrected] a retrospective Analysis of a prospectively collected Database

Background

The significance of commensal oropharyngeal flora (COF) as a potential cause of ventilator-associated pneumonia (VAP) is scarcely investigated and consequently unknown. Therefore, the aim of this study was to explore whether COF may cause VAP.

Methods

Retrospective clinical, microbiological and radiographic analysis of all prospectively collected suspected VAP cases in which bronchoalveolar lavage fluid exclusively yielded ≥ 10⁴ cfu/ml COF during a 9.5-year period. Characteristics of 899 recent intensive care unit (ICU) admissions were used as a reference population.

Results

Out of the prospectively collected database containing 159 VAP cases, 23 patients were included. In these patients, VAP developed after a median of 8 days of mechanical ventilation. The patients faced a prolonged total ICU length of stay (35 days [P < .001]), hospital length of stay (45 days [P = .001]), and a trend to higher mortality (39 % vs. 26 %, [P = .158]; standardized mortality ratio 1.26 vs. 0.77, [P = .137]) compared to the reference population. After clinical, microbiological and radiographic analysis, COF was the most likely cause of respiratory deterioration in 15 patients (9.4 % of all VAP cases) and a possible cause in 2 patients.

Conclusion

Commensal oropharyngeal flora appears to be a potential cause of VAP in limited numbers of ICU patients as is probably associated with an increased length of stay in both ICU and hospital. As COF-VAP develops late in the course of ICU admission, it is possibly associated with the immunocompromised status of ICU patients.

Diagnosis of Stroke-Associated Pneumonia

Background and Purpose—

Lower respiratory tract infections frequently complicate stroke and adversely affect outcome. There is currently no agreed terminology or gold-standard diagnostic criteria for the spectrum of lower respiratory tract infections complicating stroke, which has implications for clinical practice and research. The aim of this consensus was to propose standardized terminology and operational diagnostic criteria for lower respiratory tract infections complicating acute stroke.

Methods—

Systematic literature searches of multiple electronic databases were undertaken. An evidence review and 2 rounds of consensus consultation were completed before a final consensus meeting in September 2014, held in Manchester, United Kingdom. Consensus was defined a priori as ≥75% agreement between the consensus group members.

Results—

Consensus was reached for the following: (1) stroke-associated pneumonia (SAP) is the recommended terminology for the spectrum of lower respiratory tract infections within the first 7 days after stroke onset; (2) modified Centers for Disease Control and Prevention (CDC) criteria are proposed for SAP as follows—probable SAP: CDC criteria met, but typical chest x-ray changes absent even after repeat or serial chest x-ray; definite SAP: CDC criteria met, including typical chest x-ray changes; (3) there is limited evidence for a diagnostic role of white blood cell count or C-reactive protein in SAP; and (4) there is insufficient evidence for the use of other biomarkers (eg, procalcitonin).

Conclusions—

Consensus operational criteria for the terminology and diagnosis of SAP are proposed based on the CDC criteria. These require prospective evaluation in patients with stroke to determine their reliability, validity, impact on clinician behaviors (including antibiotic prescribing), and clinical outcomes.

A 2015 Update on Ventilator-Associated Pneumonia: New Insights on Its Prevention, Diagnosis, and Treatment

Ventilator-associated pneumonia (VAP), an infection of the lower respiratory tract which occurs in association with mechanical ventilation, is one of the most common causes of nosocomial infection in the intensive care unit (ICU). VAP causes significant morbidity and mortality in critically ill patients including increased duration of mechanical ventilation, ICU stay and hospitalization. Current knowledge for its prevention, diagnosis and management is therefore important clinically and is the basis for this review. We discuss recent changes in VAP surveillance nomenclature incorporating ventilator-associated conditions and ventilator-associated events, terms recently proposed by the Centers for Disease Control. To the extent possible, we rely predominantly on data from randomized control trials (RCTs) and meta-analyses.

Ventilator-associated infection: the role for inhaled antibiotics

PURPOSE OF REVIEW

Despite multiple protocols for the prevention of ventilator-associated pneumonia (VAP), respiratory infections have not been eliminated in the ICU. The profound disruption in both airway integrity and mucociliary clearance caused by the endotracheal tube makes it unlikely there will ever be a zero rate of respiratory infection in critically ill ventilated patients or a 100% cure rate when infection is present. In fact, options for treatment are diminishing as bacteria resistant to most, or in some hospitals all, systemic antibiotics increase in prevalence from our liberal use of systemic antibiotics. Inhaled therapy with proper delivery will result in the high concentrations of antibiotics needed in the treatment of increasingly resistant organisms.

RECENT FINDINGS

Data from many recent investigations have focused on inhaled antibiotics as: adjunctive therapy to systemic antibiotic for VAP, monotherapy for VAP, and as monotherapy for ventilator-associated tracheobronchitis. The clinical outcomes of these studies will be reviewed as well as their effect on multidrug-resistant organisms.

SUMMARY

The present review will focus on the rationale for inhaled therapy, the current studies examining the delivery and clinical efficacy of inhaled antibiotics, and the potential role for this mode of delivery actually decreasing antibiotic resistance in the respiratory tract.

Antibiotic treatment of ventilator-associated tracheobronchitis: to treat or not to treat?

PURPOSE OF REVIEW

To evaluate the data on antimicrobial therapy for ventilator-associated tracheobronchitis (VAT) to prevent ventilator-associated pneumonia (VAP), and its impact on patient outcomes.

RECENT FINDINGS

Mechanically ventilated patients are at increased risk for tracheal colonization with bacterial pathogens that may progress to VAT and/or VAP. Previous studies suggest that 10-30% of patients with VAT progress to VAP, which results in increased morbidity but not mortality. Several natural history studies and small randomized controlled trials and a meta-analysis reported that appropriate, pre-emptive antibiotic treatment for VAT reduces VAP, duration of intubation and length of ICU stay.

SUMMARY

This review focuses on diagnostic criteria for VAT and VAP, etiologic agents, rationale and benefits of initiating pre-emptive, appropriate antibiotic treatment for VAT to prevent VAP, improve patient outcomes and associated acute and chronic healthcare costs.