Previous endotracheal aspirate allows guiding the initial treatment of ventilator-associated pneumonia

Outcomes and time trends of acute respiratory distress syndrome patients with and without liver cirrhosis: an observational cohort

BACKGROUND

In studies prior to lung-protective ventilation, liver cirrhosis in acute respiratory distress syndrome (ARDS) was associated with high mortality rates. Since patients with cirrhosis have been excluded from many trials on ARDS, their outcome when treated with lung-protective ventilation is unclear. The objectives were to assess whether cirrhosis is associated with mortality in ARDS and trends over time in mortality and severity.

METHODS

We conducted a retrospective analysis of a prospective observational cohort conducted in a 20-bed tertiary ICU from October 2003 to December 2021. All consecutive adult critically ill patients with ARDS were included. ARDS was defined by the Berlin criteria. The primary outcome was 90 day mortality, assessed with Kaplan-Meier curves and multivariate Cox analysis. Time trends were assessed on 90 day mortality, Sequential Organ-Function Assessment score (SOFA) and non-hepatic SOFA. Ventilation settings were compared between patients with and without cirrhosis.

RESULTS

Of the 7155 patients screened, 863 had a diagnosis of ARDS. Among these ARDS patients, 157(18%) had cirrhosis. The overall 90 day mortality was of 43% (378/863), 57% (90/157) in patients with cirrhosis and 41% (288/706) in patients without cirrhosis (p < 0.001). On survival curves, cirrhosis was associated with 90 day mortality (p < 0.001). Cirrhosis was independently associated with 90 day mortality in multivariate analysis (hazard ratio = 1.56, 95% confidence interval 1.20-2.02). There was no change in mortality over time in ARDS patients with and without cirrhosis. SOFA (p = 0.04) and non-hepatic SOFA (p = 0.02) increased over time in ARDS patients without cirrhosis, and remained stable in ARDS patients with cirrhosis. Tidal volume, positive end-expiratory pressure, plateau pressure and driving pressure were not different between ARDS patients with and without cirrhosis.

CONCLUSIONS

Although ARDS management improved over the last decades, the 90 day mortality remained high and stable over time for both ARDS patients with (57%) and without cirrhosis (41%). Nevertheless, the severity of patients without cirrhosis has increased over time, while the severity of patients with cirrhosis has remained stable.

Are tracheal surveillance cultures useful in the intensive care unit?

Endotracheal aspirate (ETA) surveillance cultures have been used to predict the microorganisms responsible for ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients for 3 decades. However, although more than a dozen studies have been performed, the usefulness and the safety of this strategy are still debated. Tracheobronchial bacterial colonization often precedes the occurrence of VAP, and it has been postulated that the microbes present in the tracheal secretions a few days before VAP might be the same as those retrieved in the lower respiratory tract. A large number of studies, with heterogeneous designs and variable results, have questioned the possibility of predicting, by regular ETA cultures after the 48^th hour of mechanical ventilation (MV), the microbiology of VAP and therefore of determining the adequate antibiotic therapy to limit the over-prescription of broad spectrum molecules when following guidelines. Although it has shown some promising results, the strategy has not achieved unanimity because of some discordant data. The aim of this review is to provide an updated overview of the literature available in the field and to attempt to determine the strengths and weaknesses of antibiotic stewardship based on ETA surveillance cultures in VAP, particularly in the global context of drug resistant microorganism emergence and the crucial necessity of broad spectrum molecule preservation.

Quality of the aetiological diagnosis of ventilator-associated pneumonia in Spain in the opinion of intensive care specialists and microbiologists

INTRODUCTION

Current guidelines for the microbiological diagnosis of ventilator-associated pneumonia (VAP) are imprecise. Based on data provided by intensive care specialists (ICS) and microbiologists, this study defines the clinical practices and microbiological techniques currently used for an aetiological diagnosis of VAP and pinpoints deficiencies.

METHODS

Eighty hospitals in the national health network with intensive care and microbiology departments were sent two questionnaires, one for each department, in order to collect data on VAP diagnosis for the previous year.

RESULTS

Out of the 80 hospitals, 35 (43.8%) hospitals participated. These included 673 ICU beds, 32,020 ICU admissions, 173,820 ICU days stay, and generated 27,048 lower respiratory tract specimens in the year. A third of the hospitals (35%) had a microbiology department available 24/7. Most samples (83%) were tracheal aspirates. Gram stain results were immediately reported in around half (47%) of the hospitals. Quantification was made in 75% of hospitals. Molecular techniques and direct susceptibility testing were performed in 12% and one institution, respectively. Mean turnaround time for a microbiological report was 1.7 (SD; 0.7), and 2.2 (SD; 0.6) days for a negative and positive result, respectively. Telephone/in-person information was offered by 65% of the hospitals. Most (89%) ICS considered microbiological information as very useful. No written procedures were available in half the ICUs.

CONCLUSIONS

Both ICS and microbiologists agreed that present guidelines for the diagnosis of VAP could be much improved, and that a new set of consensus guidelines is urgently required. A need for guidelines to be more effectively implemented was also identified in order to improve outcomes in patients with VAP.

Pseudomonas aeruginosa colonization enhances ventilator-associated pneumonia-induced lung injury

Background

Pseudomonas aeruginosa (PA) is the single-most common pathogen of ventilator-associated pneumonia (VAP). Large quantities of PA in the trachea of ventilated patients are associated with an increased risk of death. However, the role of PA colonization in PA VAP-induced lung injury remains elusive. This study examined the effect and mechanism of PA colonization in VAP-induced lung injury.

Methods

C57BL/6 wild-type (WT) and c-Jun N-terminal kinase knockout (JNK1^−/−) mice received mechanical ventilation for 3 h at 2 days after receiving nasal instillation of PA (1 × 10⁶ colony forming unit) or normal saline.

Results

Intranasal instillation of PA or mechanical ventilation induced the expression of interleukin-6 (IL-6) in the lungs. Phospho-JNK protein expression in the lungs was significantly increased in mice receiving mechanical ventilation after PA instillation as compared with those receiving ventilation alone. Mechanical ventilation after PA instillation significantly increased the expression of tumor necrosis factor-α (TNF-α), IL-1β, and macrophage inflammatory protein-2 (MIP-2) proteins; neutrophil sequestration; and TNF-α, IL-1β, and IL-6 levels in the lungs of WT mice, but not in JNK1^−/− mice.

Conclusion

PA colonization plays an important role in PA VAP-induced lung injury through the induction of JNK1-mediated inflammation. PA-induced VAP causes lung injury through JNK signaling pathway in the lungs. JNK inhibition in ICU patients with higher percentages of PA colonization may reduce VAP-induced lung injury and mortality.

Strategies to reduce curative antibiotic therapy in intensive care units (adult and paediatric)

Emerging resistance to antibiotics shows no signs of decline. At the same time, few new antibacterials are being discovered. There is a worldwide recognition regarding the danger of this situation. The urgency of the situation and the conviction that practices should change led the Société de Réanimation de Langue Française (SRLF) and the Société Française d'Anesthésie et de Réanimation (SFAR) to set up a panel of experts from various disciplines. These experts met for the first time at the end of 2012 and have since met regularly to issue the following 67 recommendations, according to the rigorous GRADE methodology. Five fields were explored: i) the link between the resistance of bacteria and the use of antibiotics in intensive care; ii) which microbiological data and how to use them to reduce antibiotic consumption; iii) how should antibiotic therapy be chosen to limit consumption of antibiotics; iv) how can antibiotic administration be optimized; v) review and duration of antibiotic treatments. In each institution, the appropriation of these recommendations should arouse multidisciplinary discussions resulting in better knowledge of local epidemiology, rate of antibiotic use, and finally protocols for improving the stewardship of antibiotics. These efforts should contribute to limit the emergence of resistant bacteria.

Surveillance cultures in healthcare-associated pneumonia: sense or nonsense?

PURPOSE OF REVIEW

This review explores the usefulness of surveillance cultures in healthcare-associated pneumonia (HCAP).

RECENT FINDINGS

The definition of HCAP is controversial. Causative micro-organisms of HCAP resemble those found in hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Some types of surveillance cultures have proven useful in hospitalized patients. Whereas numerous studies have investigated the role of surveillance cultures in VAP, one may wonder whether surveillance culture implementation should belong in HCAP management guidelines.

SUMMARY

Studies exploring the usefulness of obtaining surveillance cultures in VAP are numerous, but are mostly retrospective, observational and/or quasi-experimental in nature. Surveillance cultures may be useful for antibiotic guidance, but positive predictive value and specificity of surveillance cultures are low, obviously negatively impacting on cost effectiveness, especially in the large population at risk for HCAP. On the other hand, multidrug-resistance is increasing and surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in ICU-admitted patients appeared useful and cost-effective. Furthermore, surveillance cultures for the presence of multidrug-resistant Gram-negative bacilli might be useful for antibiotic guidance. Currently, neither community-acquired pneumonia, HCAP, HAP nor VAP guidelines incorporate surveillance cultures. In the future, surveillance cultures in populations at risk for HCAP may be able to differentiate HCAP from other kinds of pneumonia and authorize its reason for existence.

Microbial composition and antibiotic resistance of biofilms recovered from endotracheal tubes of mechanically ventilated patients

In critically ill patients, breathing is impaired and mechanical ventilation, using an endotracheal tube (ET) connected to a ventilator, is necessary. Although mechanical ventilation is a life-saving procedure, it is not without risk. Because of several reasons, a biofilm often forms at the distal end of the ET and this biofilm is a persistent source of bacteria which can infect the lungs, causing ventilator-associated pneumonia (VAP). There is a link between the microbial flora of ET biofilms and the microorganisms involved in the onset of VAP. Culture dependent and independent techniques were already used to identify the microbial flora of ET biofilms and also, the antibiotic resistance of microorganisms obtained from ET biofilms was determined. The ESKAPE pathogens play a dominant role in the onset of VAP and these organisms were frequently identified in ET biofilms. Also, antibiotic resistant microorganisms were frequently present in ET biofilms. Members of the normal oral flora were also identified in ET biofilms but it is thought that these organisms initiate ET biofilm formation and are not directly involved in the development of VAP.

Global prospective epidemiologic and surveillance study of ventilator-associated pneumonia due to Pseudomonas aeruginosa

OBJECTIVE

To estimate the prevalence of ventilator-associated pneumonia caused by Pseudomonas aeruginosa in patients at risk for ventilator-associated pneumonia and to describe risk factors for P. aeruginosa ventilator-associated pneumonia.

DESIGN

Prospective, observational study.

SETTING

ICUs at 56 sites in 11 countries across four regions: the United States (n = 502 patients), Europe (n = 495), Latin America (n = 500), and Asia Pacific (n = 376).

PATIENTS

Adults intubated and mechanically ventilated for 48 hours to 7 days, inclusive.

INTERVENTIONS

None (local standard of care).

MEASUREMENTS AND MAIN RESULTS

Ventilator-associated pneumonia prevalence as defined by local investigators were 15.6% (293/1,873) globally, 13.5% in the United States, 19.4% in Europe, 13.8% in Latin America, and 16.0% in Asia Pacific (p = 0.04). Corresponding P. aeruginosa ventilator-associated pneumonia prevalences were 4.1%, 3.4%, 4.8%, 4.6%, and 3.2% (p = 0.49). Of 50 patients with P. aeruginosa ventilator-associated pneumonia who underwent surveillance testing, 19 (38%) had prior P. aeruginosa colonization and 31 (62%) did not (odds ratio, 7.99; 95% CI, 4.31-14.71). Of predefined risk factors for multidrug resistance (hereafter, risk factors), the most frequent in all patients were antimicrobial therapy within 90 days (51.9% of enrolled patients) and current hospitalization of more than or equal to 5 days (45.3%). None of these risk factors were significantly associated with P. aeruginosa ventilator-associated pneumonia by multivariate logistic regression. Risk factors associated with prior P. aeruginosa colonization were antimicrobial therapy within 90 days (odds ratio, 0.46; 95% CI, 0.29-0.73) and high proportion of antibiotic resistance in the community or hospital unit (odds ratio, 1.79; 95% CI, 1.14-2.82).

CONCLUSIONS

Our findings suggest that ventilator-associated pneumonia remains a common ICU infection and that P. aeruginosa is one of the most common causative pathogens. The odds of developing P. aeruginosa ventilator-associated pneumonia were eight times higher in patients with prior P. aeruginosa colonization than in uncolonized patients, which in turn was associated with local resistance.

Minimizing antibiotic exposure in the ICU: in search of the optimal strategy

The current paradigm for antibiotic management in critically ill patients is to initiate broad-spectrum therapy followed by de-escalation based on microbiological results. Routine screening cultures may allow better targeting and reduce unnecessary exposure to antibiotics.

Development of antibiotic treatment algorithms based on local ecology and respiratory surveillance cultures to restrict the use of broad-spectrum antimicrobial drugs in the treatment of hospital-acquired pneumonia in the intensive care unit: a retrospective analysis

INTRODUCTION

Timely administration of appropriate antibiotic therapy has been shown to improve outcome in hospital-acquired pneumonia (HAP). Empirical treatment guidelines tailored to local ecology have been advocated in antibiotic stewardship programs. We compared a local ecology based algorithm (LEBA) to a surveillance culture based algorithm (SCBA) in terms of appropriate coverage and spectrum of antimicrobial activity.

METHODS

We retrospectively assessed 2 hypothetical empirical antibiotic treatment algorithms for HAP on an existing high-quality prospectively collected database in a mixed 36-bed tertiary intensive care unit (ICU). Data on consecutive episodes of microbiologically confirmed HAP were collected over a period of 40 months and divided in a derivation (1 July 2009 to 31 October 2010) and validation (1 November 2010 until 31 October 2012) cohort. On the derivation cohort we constructed a LEBA, based on overall observed bacterial resistance patterns, and a SCBA, which targeted therapy to surveillance culture (SC) in the individual patient. Therapy was directed against pathogens found in respiratory SC collected two to five days before HAP, and in the absence of these, presence or absence of multi-drug resistant (MDR) pathogens in other SC dictated broad-spectrum, respectively narrow spectrum antibiotic therapy. Subsequently, LEBA and SCBA were retrospectively reviewed and compared with actually prescribed antibiotics in the validation cohort.

RESULTS

The first 100 HAP episodes made up the derivation cohort and the subsequent 113 HAP episodes the validation cohort. Appropriate antibiotic coverage rates by applying LEBA and SCBA were 88.5% and 87.6%, respectively, and did not differ significantly with respect to appropriateness of the actually prescribed initial therapy (84.1%). SCBA proposed more narrow spectrum therapy as compared to LEBA and the actually prescribed antimicrobials (P <0.001). SCBA recommended significantly less combination therapy and carbapenems compared to LEBA (P <0.001). SCBA targeted antibiotics to recent respiratory SC in 38.1% (43 out of 113 episodes) of HAP; in these cases adequacy was 93% (40 out of 43).

CONCLUSION

Rates of appropriate antimicrobial coverage were identical in LEBA and SCBA. However, in this setting of moderate MDR prevalence, the use of SCBA would result in a significant reduction of the use of broad-spectrum drugs and may be a preferential strategy when implementing antibiotic stewardship programs.

The presence of antibiotic-resistant nosocomial pathogens in endotracheal tube biofilms and corresponding surveillance cultures

Mechanically ventilated patients often develop ventilator-associated pneumonia (VAP). Soon after intubation, a mixed biofilm harboring microbial pathogens is formed on the endotracheal tube (ET). It is believed that this biofilm contributes to the development of VAP. Unfortunately, the causative agent is often not known at the time VAP is suspected, and early therapy often relies on the identification of surveillance cultures (SC). It is thus important to know whether these SC can predict the microbial flora in ET biofilms. In this study, we compare the presence of a number of antibiotic-resistant nosocomial bacteria (Enterobacter aerogenes, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis) and of Candida albicans in cultures from ET biofilms and SC (i.e. sputum samples, nose swabs, and throat swabs) of 20 mechanically ventilated patients. Our data indicate that there is a good correlation between the presence of (antibiotic-resistant) pathogens in ET biofilms and SC.

Is a strategy based on routine endotracheal cultures the best way to prescribe antibiotics in ventilator-associated pneumonia?

OBJECTIVES

The objectives of this study were to evaluate if a strategy based on routine endotracheal aspirate (ETA) cultures is better than using the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines to prescribe antimicrobials in ventilator-associated pneumonia (VAP).

METHODS

This was a prospective, observational, cohort study conducted in a 15-bed ICU and comprising 283 patients who were mechanically ventilated for ≥48 h. Interventions included twice-weekly ETA; BAL culture was done if VAP was suspected. BAL (collected at the time of VAP) plus ETA cultures (collected≤7 days before VAP) (n=146 different pairs) were defined. We compared two models of 10 days of empirical antimicrobials (ETA-based vs ATS/IDSA guidelines-based strategies), analyzing their impact on appropriateness of therapy and total antimicrobial-days, using the BAL result as the standard for comparison.

RESULTS

Complete ETA and BAL culture concordance (identical pathogens or negative result) occurred in 52 pairs; discordance (false positive or false negative) in 67, and partial concordance in two. ETA predicted the etiology in 62.4% of all pairs, in 74.0% of pairs if ETA was performed≤2 days before BAL, and in 46.2% of pairs if ETA was performed 3 to 7 days before BAL (P=.016). Strategies based on the ATS/IDSA guidelines and on ETA results led to appropriate therapy in 97.9% and 77.4% of pairs, respectively (P<.001). The numbers of antimicrobial-days were 1,942 and 1,557 for therapies based on ATS/IDSA guidelines and ETA results, respectively (P<.001).

CONCLUSIONS

The ATS/IDSA guidelines-based approach was more accurate than the ETA-based strategy for prescribing appropriate, initial, empirical antibiotics in VAP, unless a sample was available≤2 days of the onset of VAP. The ETA-based strategy led to fewer days on prescribed antimicrobials.

Value of lower respiratory tract surveillance cultures to predict bacterial pathogens in ventilator-associated pneumonia: systematic review and diagnostic test accuracy meta-analysis

PURPOSE

In ventilator-associated pneumonia (VAP), early appropriate antimicrobial therapy may be hampered by involvement of multidrug-resistant (MDR) pathogens.

METHODS

A systematic review and diagnostic test accuracy meta-analysis were performed to analyse whether lower respiratory tract surveillance cultures accurately predict the causative pathogens of subsequent VAP in adult patients. Selection and assessment of eligibility were performed by three investigators by mutual consideration. Of the 525 studies retrieved, 14 were eligible for inclusion (all in English; published since 1994), accounting for 791 VAP episodes. The following data were collected: study and population characteristics; in- and exclusion criteria; diagnostic criteria for VAP; microbiological workup of surveillance and diagnostic VAP cultures. Sub-analyses were conducted for VAP caused by Staphylococcus aureus, Pseudomonas spp., and Acinetobacter spp., MDR microorganisms, frequency of sampling, and consideration of all versus the most recent surveillance cultures.

RESULTS

The meta-analysis showed a high accuracy of surveillance cultures, with pooled sensitivities up to 0.75 and specificities up to 0.92 in culture-positive VAP. The area under the curve (AUC) of the hierarchical summary receiver-operating characteristic curve demonstrates moderate accuracy (AUC: 0.90) in predicting multidrug resistance. A sampling frequency of >2/week (sensitivity 0.79; specificity 0.96) and consideration of only the most recent surveillance culture (sensitivity 0.78; specificity 0.96) are associated with a higher accuracy of prediction.

CONCLUSIONS

This study provides evidence for the benefit of surveillance cultures in predicting MDR bacterial pathogens in VAP. However, clinical and statistical heterogeneity, limited samples sizes, and bias remain important limitations of this meta-analysis.

Implications of endotracheal tube biofilm in ventilator-associated pneumonia response: a state of concept

INTRODUCTION

Biofilm in endotracheal tubes (ETT) of ventilated patients has been suggested to play a role in the development of ventilator-associated pneumonia (VAP). Our purpose was to analyze the formation of ETT biofilm and its implication in the response and relapse of VAP.

METHODS

We performed a prospective, observational study in a medical intensive care unit. Patients mechanically ventilated for more than 24 hours were consecutively included. We obtained surveillance endotracheal aspirates (ETA) twice weekly and, at extubation, ETTs were processed for microbiological assessment and scanning electron microscopy.

RESULTS

Eighty-seven percent of the patients were colonized based on ETA cultures. Biofilm was found in 95% of the ETTs. In 56% of the cases, the same microorganism grew in ETA and biofilm. In both samples the most frequent bacteria isolated were Acinetobacter baumannii and Pseudomonas aeruginosa. Nineteen percent of the patients developed VAP (N = 14), and etiology was predicted by ETA in 100% of the cases. Despite appropriate antibiotic treatment, bacteria involved in VAP were found in biofilm (50%). In this situation, microbial persistence and impaired response to treatment (treatment failure and relapse) were more frequent (100% vs 29%, P = 0.021; 57% vs 14%, P = 0.133).

CONCLUSIONS

Airway bacterial colonization and biofilm formation on ETTs are early and frequent events in ventilated patients. There is microbiological continuity between airway colonization, biofilm formation and VAP development. Biofilm stands as a pathogenic mechanism for microbial persistence, and impaired response to treatment in VAP.

Burns, inhalation injury and ventilator-associated pneumonia: value of routine surveillance cultures

PURPOSE

Burn patients with inhalation injury are at particular risk for ventilator-associated pneumonia (VAP). Routine endotracheal surveillance cultures may provide information about the causative pathogen in subsequent VAP, improving antibiotic therapy. Our objective was to assess the incidence of VAP in burn patients with inhalation injury, and the benefit of routine surveillance cultures to predict multidrug resistant (MDR) pathogens.

PROCEDURES

Historical cohort (n=53) including all burn patients with inhalation injury requiring mechanical ventilation, admitted to the Ghent burn unit (2002-2010).

MAIN FINDINGS

Median (interquartile range) age and total burned surface area were 44y (39-55y) and 35% (19-50%). Overall, 70 episodes of VAP occurred in 46 patients (86.8%). Median mechanical ventilation days (MVD) prior to VAP onset were 7d (4-9d). The incidence was 55 episodes/1000 MVD. In 23 episodes (32.9%) at least one MDR causative pathogen was involved, mostly Pseudomonas aeruginosa and Enterobacter spp. The sensitivity and specificity of surveillance cultures to predict MDR etiology in subsequent VAP was respectively 83.0% and 96.2%. The positive and negative predictive value was 87.0% and 95.0%, respectively.

CONCLUSIONS

The incidence of VAP in burn patients with inhalation injury is high. In this cohort routine surveillance cultures had excellent operating characteristics to predict MDR pathogen involvement.

[Hot topics respiratory infections]

Revisión crítica de los artículos sobre infecciones respiratorias publicados en el último trimestre de 2008 y el presente año. En los pacientes con bronquiectasias destacan artículos que estudian su calidad de vida, así como los que analizan la disminución del número de exacerbaciones por el efecto inmunomodulador de la utilización de macrólidos a dosis bajas en estos pacientes. En el diagnóstico de la tuberculosis, son especialmente relevantes los trabajos sobre la aplicación del interferón gamma, mientras que en el tratamiento de esta afección destacan los artículos que estudian innovaciones terapéuticas en el tratamiento de la TB-MDR y TB-XDR o -TDR. En cuanto a las publicaciones referidas a las neumonías, son llamativas las que analizan la evolución de las neumonías adquiridas en la comunidad (NAC) en pacientes afectados de enfermedad pulmonar obstructiva crónica. Asimismo, cobran especial relevancia los estudios iniciales epidemiológicos y clínicos de la pandemia por gripe A (H1N1). También son de interés la valoración de las escalas pronósticas como predictoras de soporte ventilatorio y/o del uso de aminas presoras, así como el uso de los marcadores biológicos como complemento del valor predictivo de las citadas escalas pronósticas. Siguen teniendo gran interés los estudios etiológicos y clínicos de las neumonías asociadas al sistema de salud y sus posibles diferencias respecto a las NAC. En cuanto al tratamiento de las neumonías, son interesantes los análisis de la probable capacidad moduladora de la inflamación de diversos fármacos.

Microbiogical data, but not procalcitonin improve the accuracy of the clinical pulmonary infection score

OBJECTIVE

Early and adequate treatment of ventilator-associated pneumonia (VAP) is mandatory to improve the outcome. The aim of this study was to evaluate, in medical ICU patients, the respective and combined impact of the Clinical Pulmonary Infection Score (CPIS), broncho-alveolar lavage (BAL) gram staining, endotracheal aspirate and a biomarker (procalcitonin) for the early diagnosis of VAP.

DESIGN

Prospective, observational study

SETTING

A medical intensive care unit in a teaching hospital.

PATIENTS

Over an 8-month period, we prospectively included 57 patients suspected of having 86 episodes of VAP.

INTERVENTION

The day of suspicion, a BAL as well as alveolar and serum procalcitonin determinations and evaluation of CPIS were performed.

MEASUREMENTS AND MAIN RESULTS

Of 86 BAL performed, 48 were considered positive (cutoff of 10(4) cfu ml(-1)). We found no differences in alveolar or serum procalcitonin between VAP and non-VAP patients. Including procalcitonin in the CPIS score did not increase its accuracy (55%) for the diagnosis of VAP. The best tests to predict VAP were modified CPIS (threshold at 6) combined with microbiological data. Indeed, both routinely twice weekly performed endotracheal aspiration at a threshold of 10(5) cfu ml(-1) and BAL gram staining improved pre-test diagnostic accuracy of VAP (77 and 66%, respectively).

CONCLUSION

This study showed that alveolar procalcitonin performed by BAL does not help the clinician to identify VAP. It confirmed that serum procalcitonin is not an accurate marker of VAP. In contrast, microbiological resources available at the time of VAP suspicion (BAL gram staining, last available endotracheal aspirate) combined or not with CPIS are helpful in distinguishing VAP diagnosed by BAL from patients with a negative BAL.

Patterns of antimicrobial therapy in severe nosocomial infections: empiric choices, proportion of appropriate therapy, and adaptation rates--a multicentre, observational survey in critically ill patients

This prospective, observational multicentre (n=24) study investigated relationships between antimicrobial choices and rates of empiric appropriate or adequate therapy, and subsequent adaptation of therapy in 171 ICU patients with severe nosocomial infections. Appropriate antibiotic therapy was defined as in vitro susceptibility of the causative pathogen and clinical response to the agent administered. In non-microbiologically documented infections, therapy was considered adequate in the case of favourable clinical response <5 days. Patients had pneumonia (n=127; 66 ventilator-associated), intra-abdominal infection (n=23), and bloodstream infection (n=21). Predominant pathogens were Pseudomonas aeruginosa (n=29) Escherichia coli (n=26), Staphylococcus aureus (n=22), and Enterobacter aerogenes (n=21). In 49.6% of infections multidrug-resistant (MDR) bacteria were involved, mostly extended-spectrum beta-lactamase (EBSL)-producing Enterobacteriaceae and MDR non-fermenting Gram-negative bacteria. Prior antibiotic exposure and hospitalisation in a general ward prior to ICU admission were risk factors for MDR. Empiric therapy was appropriate/adequate in 63.7% of cases. Empiric schemes were classified according to coverage of (i) ESBL-producing Enterobacteriaceae and non-fermenting Gram-negative bacteria ("meropenem-based"), (ii) non-fermenting Gram-negative bacteria (schemes with an antipseudomonal agent), and (iii) first-line agents not covering ESBL-Enterobacteriaceae nor non-fermenting Gram-negative bacteria. Meropenem-based schemes allowed for significantly higher rates of appropriate/adequate therapy (p<0.001). This benefit remained when only patients without risk factors for MDR were considered (p=0.021). In 106 patients (61%) empiric therapy was modified: in 60 cases following initial inappropriate/inadequate therapy, in 46 patients in order to refine empiric therapy. In this study reflecting real-life practice, first-line use of meropenem provided significantly higher rates of the appropriate/adequate therapy, irrespective of presence of risk factors for MDR.