Impact of Methicillin Resistance on Outcome ofStaphylococcus aureusVentilator-associated Pneumonia

Treatment strategy for older patients with pneumonia independent of the risk of drug resistance in the world's top country for longevity

The number of older people with impaired swallowing function increases with aging population. Aspiration pneumonia is one of the most cases of pneumonia developing among older people. As aspiration pneumonia may develop as a result of age-related deterioration, it is crucial to consider it as an unavoidable event with aging. While pneumonia is diagnosed based on respiratory symptoms and radiological features, the lung involvement of aspiration pneumonia may be undetectable via a frontal chest radiograph in some cases. Bacterial profiles show the predominance of drug-resistant bacteria, such as Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), but isolated bacteria from respiratory samples do not necessarily indicate causative pathogens. Furthermore, there is no evidence regarding treatment superiority using broad-spectrum antibiotics compared with narrow-spectrum antibiotics. Even if isolated pathogens are a causative factor for pneumonia among older patients, the use of broad-spectrum antibiotics covering the bacteria may not improve their outcomes. Therefore, we propose a treatment strategy independent of the risk of drug resistance focusing on the discrimination of patients who are unlikely to respond to broad-spectrum antibiotics. An aspiration risk is associated with increased in-hospital mortality in patients with pneumonia, which could also lead to a greater risk of poor long-term outcomes with increased 1-year mortality. Advance care planning is now recognized as a process for communication and medical decision-making across the life course. This approach would be widely recommended for older people with aspiration risk.

Is methicillin-resistant Staphylococcus aureus a common pathogen in ventilation-associated pneumonia?: The experience of a tertiary teaching hospital in Jordan

Ventilator-associated pneumonia is a life threatening device related infection in intensive care units. Methicillin-resistant Staphylococcus aureus is considered a common contagious pathogen causing pneumonia and sepsis.To assess the prevalence of S aureus in comparison to other pathogens, and their antibacterial sensitivity profile in ventilator-associated pneumonia.Data regarding ventilator-associated pneumonia of adults admitted to the intensive care unit, at the Jordan University of Science and Technology Hospital, between 2012 and 2018 were extracted from the computerized system. Microorganisms and their susceptibility profiles were identified according to the Clinical and Laboratory Standards Institute.There were 547 isolates, of which 35 (6.4%) were Gram positive, 59% were methicillin resistant. Gram-negative isolates were present in 507 (92.6%) isolates, of which 82% were multidrug resistant, and 1% were Candida species.Gram-negative bacterial infections were significantly associated with ventilation usage. S aureus was not the predominant pathogen.

Monocyte Chemoattractant Protein-1, a Possible Biomarker of Multiorgan Failure and Mortality in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) leads to increased patients’ mortality and medical expenditure. Monocyte chemoattractant protein-1 (MCP-1) plays a role in the pathogenesis of lung inflammation and infection. Therefore, the plasma concentration of MCP-1 was assessed and correlated with the clinical course in VAP patients. This retrospective observational study recruited 45 healthy volunteers, 12 non-VAP subjects, and 30 VAP patients. The diagnostic criteria for VAP were based on the American Thoracic Society guidelines, and the level of plasma MCP-1 was determined by ELISA. Plasma MCP-1 concentration was significantly elevated in the acute stage in VAP patients when compared with the control (p < 0.0001) and non-VAP patient groups (p = 0.0006). Subsequently, it was remarkably decreased following antibiotic treatment. Moreover, plasma MCP-1 concentration was positively correlated with indices of pulmonary dysfunction, including the lung injury score (p = 0.02) and the oxygenation index (p = 0.02). When patients with VAP developed adult respiratory distress syndrome (ARDS), their plasma MCP-1 concentrations were significantly higher than those of patients who did not develop ARDS (p = 0.04). Moreover, plasma MCP-1 concentration was highly correlated with organ failure scores, including simplified acute physiology score II (SAPS II, p < 0.0001), sequential organ failure assessment score (SOFA, p < 0.0001), organ dysfunctions and/or infection (ODIN, p < 0.0001), predisposition, insult response and organ dysfunction (PIRO, p = 0.005), and immunodeficiency, blood pressure, multilobular infiltrates on chest radiograph, platelets and hospitalization 10 days before onset of VAP (IBMP-10, p = 0.004). Our results demonstrate that plasma MCP-1 is an excellent marker for recognizing VAP when the cut-off level is set to 347.18 ng/mL (area under the curve (AUC) = 0.936, 95% CI = 0.863–0.977). In conclusion, MCP-1 not only could be a biological marker related to pulmonary dysfunction, organ failure, and mortality in patients with VAP, but also could be used for early recognition of VAP.

Infectious Diseases: Pharmacologic Treatment Options for Nosocomial Pneumonia Involving Methicillin-Resistant Staphylococcus aureus

Objective:

To discuss current and potential treatment options for nosocomial pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA).

Data Sources:

A MEDLINE search (1966–January 2007) was conducted to identify English-language literature on pharmacotherapy of nosocomial pneumonia and the bibliographies of pertinent articles. Programs and abstracts from infectious disease meetings were also searched. Search terms included MRSA, nosocomial pneumonia, pulmonary infections, vancomycin, quinupristin/dalfopristin, linezolid, daptomycin, tigecycline, dalbavancin, oritavancin, and ceftobiprole.

Data Selection and Data Extraction:

All articles were critically evaluated and all pertinent information was included in this review.

Data Synthesis:

Vancomycin has been the drug of choice for MRSA infections for many years. Recent data suggest that linezolid may be superior to vancomycin in the treatment of MRSA nosocomial pneumonia. However, there are limitations to the available data. Therefore, prospective, randomized studies are needed before linezolid is recommended as the preferred first-line therapy. Other approved agents for nosocomial MRSA infections, such as quinupristin/dalfopristin and daptomycin, should not be used in the treatment of MRSA pneumonia, as they were inferior in clinical trials. Tigecycline has excellent activity against MRSA in vitro, but should not be routinely used for the treatment of MRSA pneumonia, as clinical data are lacking. In a Phase III clinical trial, an anti-MRSA cephalosporin, ceftobiprole, is being evaluated for effectiveness against nosocomial pneumonia. Investigational glycopeptides may eventually have a role in the treatment of nosocomial pneumonia, but data are currently lacking.

Conclusions:

Vancomycin is still the drug of choice for treatment of MRSA pneumonia, and linezolid should be used as an alternative agent. Linezolid should carry strong consideration for patients with vancomycin-induced nephrotoxicity or a documented lack of response to vancomycin. Tigecycline and investigational agents with activity against MRSA may be future options for nosocomial pneumonia due to MRSA.

Methicillin-resistant Staphylococcus aureus nosocomial pneumonia patients treated with ceftaroline: retrospective case series of 10 patients

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a common nosocomial pneumonia (NP) pathogen in US ICUs. Ceftaroline fosamil is a novel cephalosporin with activity against MRSA.

METHODS

We retrospectively reviewed patients (pts) who received ceftaroline therapy for MRSA NP.

RESULTS

A total of 10 pts received ceftaroline from September 2011 to September 2012 for MRSA NP. Nine pts received prior anti-MRSA therapy before initiation of ceftaroline. Ceftaroline duration of therapy ranged from 4 to 28 days. Three pts pursued palliative care prior to completion of therapy and expired off antibiotics. Of the remaining seven pts, six pts were considered to have clinical cure or improvement either at the end of therapy with ceftaroline or total antibiotic treatment. One pt had a relapse 1 week after ceftaroline treatment.

CONCLUSIONS

This case series suggests the potential of ceftaroline as an alternative agent for the treatment of MRSA NP and warrants further investigation.

Comparison of Mortality Risk Associated With Bacteremia Due to Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus

Objective.

To quantify the clinical impact of methicillin-resistance in Staphylococcus aureus causing infection complicated by bacteremia in adult patients, while controlling for the severity of patients' underlying illnesses.

Design.

Retrospective cohort study from October 1, 1995, through December 31, 2003.

Patients and Setting.

A total of 438 patients with S. aureus infection complicated by bacteremia from a single Veterans Affairs healthcare system.

Results.

We found that 193 (44%) of the 438 patients had methicillin-resistant S. aureus (MRSA) infection and 114 (26%) died of causes attributable to S. aureus infection within 90 days after the infection was identified. Patients with MRSA infection had a higher mortality risk, compared with patients with methicillin-susceptible S. aureus (MSSA) infections (relative risk, 1.7 [95% confidence interval, 1.3-2.4]; P < .01), except for patients with pneumonia (relative risk, 0.7 [95% confidence interval, 0.4-1.3]). Patients with MRSA infections were significantly older (P < .01), had more underlying diseases (P = .02), and were more likely to have severe sepsis in response to their infection (P < .01) compared with patients with MSSA bacteremia. Patients who died within 90 days after S. aureus infection was identified were significantly older (P < .01) and more likely to have severe sepsis (P < .01) and pneumonia (P = .01), compared with patients who survived. After adjusting for age as a confounder, comorbidities, and pneumonia as an effect modifier, S. aureus infection-related mortality remained significantly higher in patients with MRSA infection than in those with MSSA infection, among those without pneumonia (hazard ratio, 1.8 [95% confidence interval, 1.2-3.0]); P < .01.

Conclusions.

The results of this study suggest that patients with MRSA infections other than pneumonia have a higher mortality risk than patients with MSSA infections other than pneumonia, independent of the severity of patients' underlying illnesses.

Methicillin-resistant Staphylococcus aureus: an evolving pathogen

The horizontal transmission of methicillin resistance to Staphylococcus aureus (MRSA) in hospital and community settings, and growing prevalence of these strains, presents a significant clinical challenge to the management of serious infections worldwide. While infection control initiatives have stemmed the rising prevalence, MRSA remains a significant pathogen. More recently, evidence that MRSA is becoming resistant to glycopeptides and newer therapies raises concern about the use of these therapies in clinical practice. Vancomycin resistance has become evident in select clinical settings through rising MICs, growing awareness of heteroresistance, and emergence of intermediate-resistant and fully resistant strains. While resistance to linezolid and daptomycin remains low overall, point mutations leading to resistance have been described for linezolid, and horizontal transmission of cfr-mediated resistance to linezolid has been reported in clinical isolates. These resistance trends for newer therapies highlight the ongoing need for new and more potent antimicrobial therapies.

Methicillin-resistant Staphylococcus aureus pneumonia in adults

Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the leading etiologies of nosocomial pneumonia as a result of an increase in staphylococcal infections caused by methicillin-resistant strains paired with extended ventilatory support of critically, and often, chronically ill patients. The prevalence of community-acquired MRSA pneumonia, which historically affects younger patients and is often preceded by an influenza-like illness, is also increasing. A high index of suspicion and early initiation of appropriate antibiotics are key factors for the successful treatment of this disease. Even with early diagnosis and appropriate treatment, MRSA pneumonia still carries an unacceptably high mortality rate. This article will review historical differences between hospital-acquired and community-acquired MRSA pneumonia, as well as, clinical features of, diagnosis and treatment of MRSA pneumonia.

The impact of antimicrobial resistance and aging in VAP outcomes: experience from a large tertiary care center

Background

Ventilator associated pneumonia (VAP) is a serious infection among patients in the intensive care unit (ICU).

Methods

We reviewed the medical charts of all patients admitted to the adult intensive care units of the Massachusetts General Hospital that went on to develop VAP during a five year period.

Results

200 patients were included in the study of which 50 (25%) were infected with a multidrug resistant pathogen. Increased age, dialysis and late onset (≥5 days from admission) VAP were associated with increased incidence of resistance. Multidrug resistant bacteria (MDRB) isolation was associated with a significant increase in median length of ICU stay (19 vs. 16 days, p = 0.02) and prolonged duration of mechanical ventilation (18 vs. 14 days, p = 0.03), but did not impact overall mortality (HR 1.12, 95% CI 0.51–2.46, p = 0.77). However, age (HR 1.04 95% CI 1.01–1.07, p = 0.003) was an independent risk factor for mortality and age ≥65 years was associated with increased incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections (OR 2.83, 95% CI 1.27–6.32, p = 0.01).

Conclusions

MDRB-related VAP is associated with prolonged ICU stay and mechanical ventilation. Interestingly, age ≥ 65 years is associated with MRSA VAP.

Epidemiology and outcomes of ventilator-associated pneumonia in northern Brazil: an analytical descriptive prospective cohort study

BACKGROUND

Ventilator-associated pneumonia (VAP) is considered the most common nosocomial infection in the intensive care unit (ICU), but its features are not fully known in many hospitals in Brazil. We identified clinical and epidemiological aspects associated with VAP in an intensive care unit (ICU) in a general public hospital in northern Brazil and performed an analytical descriptive prospective cohort study.

METHODS

We analyzed data from thirty-three patients who developed VAP while in the ICU. Clinical and epidemiological data of patients were obtained and tracheal secretions were submitted to culture. Microbial isolates were identified and evaluated for resistance against antimicrobial agents by using the automated Vitek 2 system.

RESULTS

The frequency of VAP was 26.2% in patients submitted to invasive mechanical ventilation for at least 48 hours, and death occurred in 78.8% of cases. Only the presence of comorbidity showed a significant association (P = 0.029) with death. The most commonly found bacteria were Pseudomonas aeruginosa, Acinetobacter spp., and Enterobacteriaceae. We also found a frequency of 54.5% of multiresistant bacteria associated with VAP, and previous antibiotic therapy was used in 97% of patients.

CONCLUSIONS

VAP in our ICU presented with a high frequency and was mainly caused by multiresistant bacteria. Implementation of rational protocols for the use of antibacterial agents and rapid delivery of culture and susceptibility test results are essential. This may help decrease VAP-related mortality rates by multiresistant bacteria in the ICU.

Impact of multidrug resistance on Pseudomonas aeruginosa ventilator-associated pneumonia outcome: predictors of early and crude mortality

The prevalence of multidrug-resistant (MDR) Pseudomonas aeruginosa has increased over the past decade and a significant rise in these isolates in ventilator-associated pneumonia (VAP) has been observed. However, the impact of MDR on VAP outcome has not been analysed in depth. We investigated the risk factors for early and crude mortality in a retrospective study of microbiologically and clinically documented VAP. Ninety-one VAP episodes in 83 patients were included, 31 caused by susceptible P. aeruginosa and 60 by MDR strains, of which 42 (70 %) were extensively drug-resistant (XDR) P. aeruginosa. Thirteen episodes concomitantly presented P. aeruginosa bacteraemia, in seven of which the origin was the respiratory tract. Whereas susceptible P. aeruginosa episodes were more likely than MDR episodes to receive adequate empirical (68 % vs. 30 %; p < 0.001) and definitive antimicrobial therapy (96 % vs. 50 %; p < 0.001), susceptible P. aeruginosa VAP presented a trend towards early mortality (29 % vs. 15 %; p = 0.06). A logistic regression model with early mortality as the dependent variable identified multiorgan dysfunction syndrome (MODS) [odds ratio (OR) 10.4; 95 % confidence interval (CI) 1.7-63.5; p = 0.01] and inadequate antibiotic therapy (OR 4.27; 95 % CI 0.98-18.4; p = 0.052) as independent risk factors for early mortality. A similar analysis identified MODS (OR 4.31; 95 % CI 1.14-16.2; p = 0.03) as the only independent predictor of crude mortality. The severity of acute illness clinical presentation was the main predictor of mortality. Despite adequate antibiotic therapy, susceptible P. aeruginosa seems to cause major early mortality. Although adequate therapy is essential to treat VAP, the severity of acute illness is a more important factor than drug resistance.

Relationship of teicoplanin MICs to treatment failure in teicoplanin-treated patients with methicillin-resistant Staphylococcus aureus pneumonia

BACKGROUND/PURPOSE

The objective of this study was to determine the predictive value of teicoplanin minimal inhibitory concentrations (MICs) for treatment failure among patients with methicillin-resistant Staphylococcus aureus (MRSA) pneumonia.

METHODS

In this study, all patients with ≥1 tracheal aspirates or sputum cultures positive for MRSA admitted to the hospital between April 2011 and September 2011 were reviewed. We enrolled patients who are ≥18 years of age, with a diagnosis of pneumonia, and with a receipt of teicoplanin therapy throughout the course. The relationship between teicoplanin Etest MICs and treatment outcomes of MRSA pneumonia was analyzed to identify the breakpoint of teicoplanin MICs influencing treatment outcomes.

RESULTS

Of the 80 patients enrolled, 31 had a lower teicoplanin MIC level (<2.0 mg/L) and 49 had a higher MIC level (≥2.0 mg/L) for MRSA. The lower MIC group had a higher clinical resolution rate in 14 days [24 (77.4%) vs. 23 (46.9%), p = 0.007] and a lower treatment failure rate at the end of teicoplanin treatment [4 (12.9%) vs. 18 (36.7%), p = 0.020]. A comparison between the treatment success and failure groups showed that the former had a longer duration of teicoplanin use (18.76 ± 10.34vs.12.41 ± 5.65 days; p = 0.014). Results of a multivariate analysis showed that teicoplanin MICs ≥ 2.0 mg/Land shorter duration of teicoplanin therapy were independent risk factors for treatment failure.

CONCLUSION

A higher teicoplanin MIC value (≥2.0 mg/L) may predict the treatment failure among patients with teicoplanin-treated MRSA pneumonia.

Attributable mortality of ventilator-associated pneumonia

PURPOSE OF REVIEW

To critically discuss the attributable mortality of ventilator-associated pneumonia (VAP) and potential sources of variation.

RECENT FINDINGS

The review will cover the available estimates (0-50%). It will also explore the source of variation because of definition of VAP (being lower if inaccurate), case-mix issues (being lower for trauma patients), the severity of underlying illnesses (being maximal when the severity of underlying illness is intermediate), and on the characteristics and the severity of the VAP episode. Another important source of variation is the use of poorly appropriate statistical models (estimates biased by lead time bias and competing events). New extensions of survival models which take into account the time dependence of VAP occurrence and competing risks allow less biased estimation as compared with traditional models.

SUMMARY

Attributable mortality of VAP is about 6%. Accurate diagnostic methods are key to properly estimating it. Traditional statistical models should no longer be used to estimate it. Prevention efforts targeted on patients with intermediate severity may result in the most important outcome benefits.

Analysis of pathogen and host factors related to clinical outcomes in patients with hospital-acquired pneumonia due to methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial pneumonia. To characterize pathogen-derived and host-related factors in intensive care unit (ICU) patients with MRSA pneumonia, we evaluated the Improving Medicine through Pathway Assessment of Critical Therapy in Hospital-Acquired Pneumonia (IMPACT-HAP) database. We performed multivariate regression analyses of 28-day mortality and clinical response using univariate analysis variables at a P level of <0.25. In isolates from 251 patients, the most common molecular characteristics were USA100 (55.0%) and USA300 (23.9%), SCCmec types II (64.1%) and IV (33.1%), and agr I (36.7%) and II (61.8%). Panton-Valentine leukocidin (PVL) was present in 21.9%, and vancomycin heteroresistance was present in 15.9%. Mortality occurred in 37.1% of patients; factors in the univariate analysis were age, APACHE II score, AIDS, cardiac disease, vascular disease, diabetes, SCCmec type II, PVL negativity, and higher vancomycin MIC (all P values were <0.05). In multivariate analysis, independent predictors were APACHE II score (odds ratio [OR], 1.090; 95% confidence interval [CI], 1.041 to 1.141; P < 0.001) and age (OR, 1.024; 95% CI, 1.003 to 1.046; P = 0.02). Clinical failure occurred in 36.8% of 201 evaluable patients; the only independent predictor was APACHE II score (OR, 1.082; 95% CI, 1.031 to 1.136; P = 0.002). In summary, APACHE II score (mortality, clinical failure) and age (mortality) were the only independent predictors, which is consistent with severity of illness in ICU patients with MRSA pneumonia. Interestingly, our univariate findings suggest that both pathogen and host factors influence outcomes. As the epidemiology of MRSA pneumonia continues to evolve, both pathogen- and host-related factors should be considered when describing epidemiological trends and outcomes of therapeutic interventions.

Ventilator-associated pneumonia due to meticillin-resistant Staphylococcus aureus: risk factors and outcome in a large general hospital

BACKGROUND

Data about risk factors and impact on outcome of methicillin-resistant S. aureus (MRSA) in unselected patients with ventilator-associated pneumonia (VAP) are limited.

AIM

To assess predisposing factors and outcome of VAP due to MRSA in a large teaching institution.

METHODS

Prospective study carried out over four years in the three adult ICUs of our hospital. Patients with MRSA-VAP were compared with those with bacterial VAP due to other microorganisms.

FINDINGS

Overall, 474 episodes of bacterial VAP were collected. Significant differences between MRSA-VAP (111) and VAP due to other microorganisms (363) were found for median age (68 vs. 62 years), median APACHE II score (12 vs. 11), neurosurgery (5.4% vs. 13.8%), abdominal surgery (35% vs. 19%), prior treatment with any antibiotic (82.9% vs. 64.5%) and with imipenem (24% vs. 11%) at present admission before VAP, and pleural effusion (12% vs. 5%). Multivariate analysis adjusted for confounding factors showed that higher APACHE II score, prior treatment with any antibiotic and pleural effusion were independent risk factors for MRSA. As for treatment and outcome, the differences between MRSA-VAP and other VAP were inadequate empiric treatment (70% vs. 53%), median cost of antibiotics per episode (€974 vs. €726), and in-hospital mortality (60% vs. 47%). At multivariate analysis, however, MRSA was not found to be an independent risk factor for mortality.

CONCLUSION

MRSA is a common cause of VAP. Underlying conditions predispose to its high mortality.

Overview of antimicrobial therapy in intensive care units

In the management of a patient with severe sepsis, it is important to suspect the infection early, to collect samples immediately after diagnosis and to promptly initiate a broad-spectrum antibiotic treatment. The choice of this empirical antimicrobial therapy should be based on host characteristics, site of infection, local ecology and pharmacokinetics/pharmacodynamics of antibiotics. In severe infection, guidelines recommend the use of a combination of antibiotics. After results of cultures are obtained, treatment should be re-evaluated to either de-escalate or escalate the antibiotic prescription. This is associated with optimal costs, decreased incidence of superinfection and minimal development of antimicrobial resistance. All these steps should rely on written protocols, and the compliance to these protocols should be continuously monitored in order to detect violations and implement corrective procedures.

Nosocomial methicillin resistant Staphylococcus aureus pneumonia - epidemiology and trends based on data of a network of 586 German ICUs (2005-2009)

The epidemiology of MRSA pneumonia varies across countries. One of the most import risk factors for the development of nosocomial MRSA pneumonia is mechanical ventilation. Methicillin resistance in S. aureus ventilator associated pneumonia (VAP) ranged between 37% in German, 54% in the US American and 78% in Asian and Latin American ICUs. In 2009, the incidence density of nosocomial VAP caused by MRSA was 0.28 per 1000 ventilation days in a network of 586 German ICUs. Incidences peaked in neurological and neurosurgical ICUs. Crude hospital mortality in studies performed after 2005 lay between 27% and 59% and attributable MRSA pneumonia mortality at 40%. Since 2005, US American and German data indicate decreasing trends for MRSA pneumonia. Measures to reduce MRSA pneumonia or to control the spread of MRSA include hand hygiene, standard and contact precautions, oral contamination with chlor hexidine, skin decontamination with antiseptics, screening, and (possibly) patient isolation in a single room.

Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

Clinical impact of methicillin resistance on outcome of patients with Staphylococcus aureus infection: a stratified analysis according to underlying diseases and sites of infection in a large prospective cohort

OBJECTIVE

This study was conducted to identify the predictors of mortality and to evaluate the impact of methicillin resistance on outcome in patients with Staphylococcus aureus infection according to underlying conditions and type of infection.

METHODS

An observational cohort study including 4949 patients with S. aureus infection was conducted. We compared data from patients with MRSA infection with those with MSSA infection.

RESULTS

The 30-day mortality rate of MRSA group was significantly higher than that of MSSA group (15.6% vs. 6.2%, P < 0.001). However, MRSA infection was not found to be independent risk factor for mortality after adjusting for other variables (OR = 1.03, 95% CI = 0.80-1.32). When we analyzed patients with S. aureus bacteremia (n = 709), MRSA infection was found to be significantly associated with mortality in multivariate analysis (Adjusted OR = 1.69, 95% CI = 1.15-2.49). When the 30-day mortality rates were compared according to underlying diseases, the 30-day mortality rate of MRSA group was significantly higher than that of MSSA group in patients with malignancy or renal diseases. MRSA infection was also found to be one of the independent risk factors for mortality in patients with malignancy (adjusted OR = 1.69, 95% CI = 1.06-2.70) and in those with renal disease (adjusted OR = 1.70, 95% CI = 1.0-2.89), after adjustment for host variables.

CONCLUSIONS

Methicillin resistance adversely affected the outcome of patients with S. aureus infection, in patients with cancer or renal disease and in those with S. aureus bacteremia, although MRSA infection was not found to be significantly associated with higher mortality in overall patient population.

Attributable mortality of ventilator-associated pneumonia: respective impact of main characteristics at ICU admission and VAP onset using conditional logistic regression and multi-state models

PURPOSE

Methods for estimating the excess mortality attributable to ventilator-associated pneumonia (VAP) should handle VAP as a time-dependent covariate, since the probability of experiencing VAP increases with the time on mechanical ventilation. VAP-attributable mortality (VAP-AM) varies with definitions, case-mix, causative microorganisms, and treatment adequacy. Our objectives here were to compare VAP-AM estimates obtained using a traditional cohort analysis, a multistate progressive disability model, and a matched-cohort analysis; and to compare VAP-AM estimates according to VAP characteristics.

METHODS

We used data from 2,873 mechanically ventilated patients in the Outcomerea database. Among these patients from 12 intensive care units, 434 (15.1%) experienced VAP; of the remaining patients, 1,969 (68.5%) were discharged alive and 470 (16.4%) died. With the multistate model, VAP-AM was 8.1% (95% confidence interval [95%CI], 3.1-13.1%) for 120 days' complete observation, compared to 10.4% (5.6-24.5%) using a matched-cohort approach (2,769 patients) with matching on mechanical ventilation duration followed by conditional logistic regression. VAP-AM was higher in surgical patients and patients with intermediate (but not high) Simplified Acute Physiologic Score II values at ICU admission. VAP-AM was significantly influenced by time to VAP but not by resistance of causative microorganisms. Higher Logistic Organ Dysfunction score at VAP onset dramatically increased VAP-AM (to 31.9% in patients with scores above 7).

CONCLUSION

A multistate model that appropriately handled VAP as a time-dependent event produced lower VAP-AM values than conditional logistic regression. VAP-AM varied widely with case-mix. Disease severity at VAP onset markedly influenced VAP-AM; this may contribute to the variability of previous estimates.

Risk factors for relapse of ventilator-associated pneumonia in trauma patients

BACKGROUND

Our goal was to define risk factors for ventilator-associated pneumonia (VAP) relapse and examine the implications, if any, for initial therapy in trauma patients.

METHODS

Trauma patients cared for in the surgical intensive care unit during a 48-month period with confirmed VAP recurrence were evaluated. Recurrent VAP was defined as a positive quantitative culture (> or = 10(4) colony-forming units/mL in a bronchoalveolar lavage or protected catheter lavage specimen) > or = 4 days after initiation of antibiotics for the primary episode. Recurrence with at least one of the initial causative pathogens was defined as a relapse. Initial causal pathogen, Acute Physiology and Chronic Health Evaluation II score, injury severity score, Glasgow Coma Score (GCS), age, white blood cell count (WBC), and duration of hospital stay before diagnosis were analyzed in univariate and multivariate regression models.

RESULTS

A total of 55 patients met the criteria of recurrent VAP. Of these 55 recurrences, 19 (35%) were relapses. Acute Physiology and Chronic Health Evaluation II score, injury severity score, and GCS were not associated with VAP relapse by univariate analyses. Patients who relapsed had primary VAP involving nonfermenting gram-negative bacilli (NFGNB) (Acinetobacter, Pseudomonas, and Stenotrophomonas species) more frequently than other organisms (68% vs. 32%, p = 0.001). Primary VAP with NFGNB was found to be a significant predictor of VAP relapse by univariate and multivariate logistic regression analysis (OR = 5.1, p = 0.003; OR = 4.63, p = 0.005, respectively).

CONCLUSIONS

There is a high rate of VAP relapse associated with primary infection by NFGNB, suggesting initial treatment failure. Trauma patients with primary VAP involving these organisms may benefit from increased surveillance for relapse.

Frequency and predictors of ventilator-associated pneumonia recurrence: a meta-analysis

Large clinical series focusing on the risk factors associated with recurrence after the onset of an initial episode of ventilator-associated pneumonia (VAP) produced inconsistent results. A meta-analysis would be helpful to shed light on the issue. Our objective was to estimate the frequency of VAP recurrence and to identify risk factors associated with it. PubMed, Scopus, Current Contents, and references of retrieved articles were searched without language restrictions. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by using both the Mantel-Haenszel fixed-effect and the DerSimonian-Laird random effects models. The overall frequency of VAP recurrence in 969 patients of the seven eligible reports was 26.8%. Among the 20 evaluated risk factors, only acute lung injury/acute respiratory distress syndrome (OR, 1.76; 95% CI, 1.12-2.75) and shock (OR, 1.55; 95% CI, 1.01-2.41) at the day of diagnosis of the first VAP episode were found to be associated with VAP recurrence. There was also evidence, albeit inconsistent, that severity of illness at intensive care unit admission was associated with VAP recurrence. Recurrence involves almost one in four cases of VAP and is associated with acute lung injury/acute respiratory distress syndrome and shock, but not with first-episode causative pathogens. Recognition of these predictors may permit the timely implementation of measures to prevent recurrence of VAP.

Determinants and impact of multidrug antibiotic resistance in pathogens causing ventilator-associated-pneumonia

INTRODUCTION

The idea that multidrug resistance (MDR) to antibiotics in pathogens causing ventilator-associated pneumonia (VAP) is an independent risk factor for adverse outcome is still debated. We aimed to identify the determinants of MDR versus non-MDR microbial aetiology in VAP and assessed whether MDR versus non-MDR VAP was independently associated with increased 30-day mortality.

METHODS

We performed a retrospective analysis of a prospectively registered cohort of adult patients with microbiologically confirmed VAP, diagnosed at a university hospital intensive care unit during a three-year period. Determinants of MDR as compared with non-MDR microbial aetiology and impact of MDR versus non-MDR aetiology on mortality were investigated using multivariate logistic and competing risk regression analysis.

RESULTS

MDR pathogens were involved in 52 of 192 episodes of VAP (27%): methicillin-resistant Staphylococcus aureus in 12 (6%), extended-spectrum beta-lactamase producing Enterobacteriaceae in 28 (15%), MDR Pseudomonas aeruginosa and other non-fermenting pathogens in 12 (6%). Multivariable logistic regression identified the Charlson index of comorbidity (odds ratio (OR) = 1.38, 95% confidence interval (CI) = 1.08 to 1.75, p = 0.01) and previous exposure to more than two different antibiotic classes (OR = 5.11, 95% CI = 1.38 to 18.89, p = 0.01) as predictors of MDR aetiology. Thirty-day mortality after VAP diagnosis caused by MDR versus non-MDR was 37% and 20% (p = 0.02), respectively. A multivariate competing risk regression analysis showed that renal replacement therapy before VAP (standardised hazard ratio (SHR) = 2.69, 95% CI = 1.47 to 4.94, p = 0.01), the Charlson index of comorbidity (SHR = 1.21, 95% CI = 1.03 to 1.41, p = 0.03) and septic shock on admission to the intensive care unit (SHR = 1.86, 95% CI = 1.03 to 3.35, p = 0.03), but not MDR aetiology of VAP, were independent predictors of mortality.

CONCLUSIONS

The risk of MDR pathogens causing VAP was mainly determined by comorbidity and prior exposure to more than two antibiotics. The increased mortality of VAP caused by MDR as compared with non-MDR pathogens was explained by more severe comorbidity and organ failure before VAP.

[Impact on morbidity and costs of methicillin-resistant Staphylococcus aureus nosocomial pneumonia in intensive care patients]

OBJECTIVES

Prevention of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections in the intensive care units (ICU) has been recommended for several years. However, the workload and the costs of these programs are to be weighed against the benefit obtained in terms of reduction of morbidity and costs induced by the infection. The purpose of this study was to evaluate the cost and the current morbidity of the infection with MRSA in the ICU.

METHODS

In a retrospective case-control study carried out in 2004, all patients of the 6 intensive care units of a teaching hospital having developed a MRSA nosocomial infection were included. They were paired with controls on the following criteria: department, Simplified Acute Physiology Score II (SAPSII), age (+/- 5 years), type of surgery (for the surgical intensive care units). The duration of hospitalization of the paired control had to be at least equal to the time from admission to infection of the infected patient. The costs were evaluated using the following parameters: scores omega 1, 2 and 3, duration of artificial ventilation, hemodialysis, length of ICU stay, radiological procedures, surgical procedures, total antibiotic cost and other expensive drugs.

RESULTS

Twenty-one patients with MRSA infection were included. All had nosocomial pneumonia. The 21 paired patients were similar with regard to both initial criteria and sex. Hospital mortality was not different between the 2 groups (cases=8; controls=6; p=0.41), as well as median duration of hospital stay (cases=41 days; controls=43 days; p=0.9). The duration of mechanical ventilation, number of hemodialysis or hemofiltration sessions, number of radiological procedures were similar in both groups. The total omega score was not significantly different between cases (median 435; IQR: 218-579) and controls (median 281, IQR: 231-419; p=0.55). The median duration of isolation was 12 days for cases and 0 day for controls (p=0.0007). The pharmaceutical expenditure was significantly higher in cases (median: 1414euro; IQR: 795-4349), by comparison with the controls (median: 877euro, IQR: 687-2496) (p=0.049).

CONCLUSION

In the ICU having set up a policy intended to reduce the risk of MRSA nosocomial infections, MRSA pneumonia does not seem to involve major additional morbidity, as compared to a control population matched for similar severity of illness. It increases modestly the use of the medical resources.

Risk factors for treatment failure in patients with ventilator-associated pneumonia receiving appropriate antibiotic therapy

PURPOSE

The aim of this study was to investigate modifiable risk factors and predictors for treatment failure (TF) in patients with ventilator-associated pneumonia (VAP) receiving appropriate antibiotic therapy.

MATERIALS AND METHODS

An observational cohort study performed in an intensive care unit (ICU) of a University hospital. Eighty-nine patients with VAP were enrolled in the study consecutively. Treatment failure was defined as lack of clinical and microbiological response to therapy within 2 weeks. Potential risk factors for TF, related with patients, microorganisms, and ICU therapies, were evaluated.

RESULTS

Mean age was 72 +/- 13 years. Fifty-three of the patients had TF. Patients with TF were older, had more comorbidities, higher admission and Acute Physiology and Chronic Health Evaluation Score (APACHE II)-VAP scores, lower daily carbohydrate intake, and lymphocyte number below 1000/mm(3) than the treatment success group. Transfusions, bacteremia, infection with multidrug-resistant microorganisms, initial bacterial load (CFU/mL), and steroid therapy were similar across the groups. Comorbidity (odds ratio [OR], 4.4; 95% CI, 1.2-16.8; P = .030), VAP-APACHE II scores above 16 (OR, 6.4; 95% CI, 2.1-18.6; P = .001), daily carbohydrate intake below 190 g/d (OR, 3; 95% CI,1.1-8.6; P = .038), lymphocyte number below 1000/mm3 (OR, 4.1; 95% CI, 1.3-12.9; P = .014) were independent predictors for TF.

CONCLUSIONS

Patients with comorbidities, who are severely ill and lymphocytopenic at the time of VAP diagnosis, are at high risk for TF.

Ventilator-associated pneumonia caused by multidrug-resistant organisms or Pseudomonas aeruginosa: prevalence, incidence, risk factors, and outcomes

PURPOSE

The aim of this study was to clarify the prevalence and incidence of, risk factors for, and outcomes from suspected ventilator-associated pneumonia (VAP) associated with the isolation of either Pseudomonas or multidrug-resistant (MDR) bacteria ("high risk" pathogens) from respiratory secretions.

MATERIALS AND METHODS

Data were collected as part of a large, multicentered trial of diagnostic and therapeutic strategies for patients (n = 739) with suspected VAP.

RESULTS

At enrollment, 6.4% of patients had Pseudomonas species, and 5.1% of patients had at least 1 MDR organism isolated from respiratory secretions. Over the study period, the incidence of Pseudomonas and MDR organisms was 13.4% and 9.2%, respectively. Independent risk factors for the presence of these pathogens at enrollment were duration of hospital stay >or=48 hours before intensive care unit (ICU) admission (odds ratio, 2.37 [95% CI, 1.40-4.02]; P = .001] and prolonged duration of ICU stay before enrollment (odds ratio, 1.50 [95% CI, 1.17-1.93]; P = .002] per week. Fewer patients whose specimens grew either Pseudomonas or MDR organisms received appropriate empirical antibiotic therapy compared to those without these pathogens (68.5% vs 93.9%, P < .001). The isolation of high risk pathogens from respiratory secretions was associated with higher 28-day (relative risk, 1.59 [95% CI, 1.07-2.37]; P = .04] and hospital mortality (relative risk, 1.48 [95% CI, 1.05-2.07]; P = .05), and longer median duration of mechanical ventilation (12.6 vs 8.7 days, P = .05), ICU length of stay (16.2 vs 12.0 days, P = .05), and hospital length of stay (55.0 vs 41.8 days, P = .05).

CONCLUSIONS

In this patient population, the incidence of high-risk organisms newly acquired during an ICU stay is low. However, the presence of high risk pathogens is associated with worse clinical outcomes.

Overcrowding and understaffing in modern health-care systems: key determinants in meticillin-resistant Staphylococcus aureus transmission

Recent decades have seen the global emergence of meticillin-resistant Staphylococcus aureus (MRSA), causing substantial health and economic burdens on patients and health-care systems. This epidemic has occurred at the same time that policies promoting higher patient throughput in hospitals have led to many services operating at, or near, full capacity. A result has been limited ability to scale services according to fluctuations in patient admissions and available staff, and hospital overcrowding and understaffing. Overcrowding and understaffing lead to failure of MRSA control programmes via decreased health-care worker hand-hygiene compliance, increased movement of patients and staff between hospital wards, decreased levels of cohorting, and overburdening of screening and isolation facilities. In turn, a high MRSA incidence leads to increased inpatient length of stay and bed blocking, exacerbating overcrowding and leading to a vicious cycle characterised by further infection control failure. Future decision making should use epidemiological and economic evidence to evaluate the effect of systems changes on the incidence of MRSA infection and other adverse events.

[Summary of the GEIPC-SEIMC and GTEI-SEMICYUC recommendations for the treatment of infections caused by gram positive cocci in critical patients]

OBJECTIVE

In recent years there has been an increase in infections caused by gram-positive cocci in critical patients, together with a rapid development of resistance to the antibiotics which are normally used to treat them. The objective is to prepare an antibiotic treatment guide for the most common infections caused by gram positive cocci in critical patients. This guide will help in the decision-making process regarding the care of such patients.

METHOD

Experts from two scientific societies worked together to prepare a consensus document. They were members of the Study Group on Infections in Critical Patients (GEIPC), which is part of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), and the Infectious Diseases Working Group (GTEI), belonging to the Spanish Society of Intensive Care Medicine and Coronary Units (SEMICYUC). There was a systematic review of the literature published up to September 2006 regarding this type of infections and the antibiotic treatments marketed to that date. An evidence grading system was applied according to the strength of the recommendation (categories A, B or C) and the level of evidence (categories I, II or III). Recommendations were given if there was consensus among the experts from both societies.

RESULTS

The antibiotic regimens recommended for treating infections caused by gram-positive cocci were presented in the form of tables, showing the recommendation grade. Alternatives were given for allergic patients. The scientific basis supporting the aforementioned recommendations is explained within the text and the references upon which they are based are cited.

CONCLUSIONS

A summary of an evidence-based practical guide for the treatment of infections caused by gram-positive cocci in critical patients is presented.

Guidelines for the management of hospital-acquired pneumonia in the UK: report of the working party on hospital-acquired pneumonia of the British Society for Antimicrobial Chemotherapy

These evidence-based guidelines have been produced after a systematic literature review of a range of issues involving prevention, diagnosis and treatment of hospital-acquired pneumonia (HAP). Prevention is structured into sections addressing general issues, equipment, patient procedures and the environment, whereas in treatment, the structure addresses the use of antimicrobials in prevention and treatment, adjunctive therapies and the application of clinical protocols. The sections dealing with diagnosis are presented against the clinical, radiological and microbiological diagnosis of HAP. Recommendations are also made upon the role of invasive sampling and quantitative microbiology of respiratory secretions in directing antibiotic therapy in HAP/ventilator-associated pneumonia.

Secular changes in incidence and mortality associated with Staphylococcus aureus bacteraemia in Quebec, Canada, 1991-2005

In order to examine secular changes in the incidence and mortality associated with Staphylococcus aureus bacteraemia before and after the emergence of methicillin-resistant S. aureus (MRSA), a retrospective cohort study of 815 patients with S. aureus bacteraemia was performed in the Estrie region of Quebec, Canada, between 1991 and 2005. The primary outcome was all-cause 30-day mortality. Between 1991-1993 and 2003-2005, the proportion of cases attributed to endocarditis and pneumonia increased from 4% to 11% and from 2% to 11%, respectively, while that attributed to catheter infections decreased from 49% to 17%. MRSA was almost absent in 1991-1999, but accounted for 10% and 20% of cases in 2000-2002 and 2003-2005, respectively. The population incidence of bacteraemia caused by methicillin-susceptible S. aureus (MSSA) remained stable between 1997 and 2005, while that of MRSA increased from 0 to 7.4/100 000. Risk-factors for mortality included age, co-morbidities, female gender, residence outside the city of Sherbrooke, pneumonia (OR 3.35, 95% CI 1.96-5.73) or endocarditis (OR 2.89, 95% CI 1.67-5.01) as the source, and an absence of treatment. After adjusting for confounders, patients with MRSA bacteraemia had a higher mortality rate than those with MSSA bacteraemia (OR 2.21, 95% CI 0.99-4.96, p 0.053). Mortality in patients with MSSA bacteraemia was 19% (16/83) in 1991-1993, 23% (26/113) in 1994-1996, 29% (50/173) in 1997-1999, and 28% (52/185) in 2000-2002, decreasing to 15% (28/192) in 2003-2005, which impacted on the relative mortality rates of MRSA and MSSA. MRSA did not replace, but added to, an existing stable incidence of MSSA bacteraemia.

[GEIPC-SEIMC (Study Group for Infections in the Critically Ill Patient of the Spanish Society for Infectious Diseases and Clinical Microbiology) and GTEI-SEMICYUC ( Working Group on Infectious Diseases of the Spanish Society of Intensive Medicine, Critical Care, and Coronary Units) recommendations for antibiotic treatment of gram-positive cocci infections in the critical patient]

In recent years, an increment of infections caused by gram-positive cocci has been documented in nosocomial and hospital-acquired-infections. In diverse countries, a rapid development of resistance to common antibiotics against gram-positive cocci has been observed. This situation is exceptional in Spain but our country might be affected in the near future. New antimicrobials active against these multi-drug resistant pathogens are nowadays available. It is essential to improve our current knowledge about pharmacokinetic properties of traditional and new antimicrobials to maximize its effectiveness and to minimize toxicity. These issues are even more important in critically ill patients because inadequate empirical therapy is associated with therapeutic failure and a poor outcome. Experts representing two scientific societies (Grupo de estudio de Infecciones en el Paciente Crítico de la SEIMC and Grupo de trabajo de Enfermedades Infecciosas de la SEMICYUC) have elaborated a consensus document based on the current scientific evidence to summarize recommendations for the treatment of serious infections caused by gram-positive cocci in critically ill patients.

Risk factors for infective endocarditis and outcome of patients with Staphylococcus aureus bacteremia

OBJECTIVE

To investigate the risk factors for Staphylococcus aureus infective endocarditis (SAIE) and 6-month mortality in patients with S aureus bacteremia (SAB).

PATIENTS AND METHODS

This study consisted of patients who were diagnosed as having nosocomial or community-acquired SAB or SAIE between June 1, 2000, and December 31, 2005. Clinical characteristics of patients with SAB were compared with those of patients with SAIE, and predictors of mortality in patients with SAB were analyzed.

RESULTS

The median age of the 132 randomly selected patients with SAB and the 66 patients with SAIE was 66 and 68 years, respectively. Univariable analysis showed that unknown origin of SAB, a valvular prosthesis, a pacemaker, persistent fever, and persistent bacteremia were significantly associated with SAIE. In multivariable analysis, unknown origin of SAB (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.9-9.3; P=.001), a valvular prosthesis (OR, 9.2; 95% CI, 3.2-26.2; P<.001), persistent fever (OR, 3.1; 95% CI, 1.0-9.0; P=.04), and persistent bacteremia (OR, 6.8; 95% CI, 2.3-20.2- P=.001) were independently associated with SAIE. Six- month mortality was 8% in patients with SAB vs 35% in patients with SAIE (OR, 6.5; 95% CI, 2.9- 14.8; P<.001). In univariable analysis, methicillin- resistant S aureus (OR, 7.2; 95% CI, 1.7 - 29.4; P=.005) was significantly associated with 6-month mortality in patients with SAB.

CONCLUSION

Unknown origin of SAB, a valvular prosthesis, persistent fever, and persistent bacteremia were independently associated with SAIE in patients with SAB. In univariable analysis, methicillin-resistant S aureus was associated with 6-month mortality in patients with SAB. S aureus infective endocarditis had a significantly higher mortality than SAB. The optimal management of SAB and SAIE deserves further study.

Recomendaciones GEIPC-SEIMC y GTEI-SEMICYUC para el tratamiento antibiótico de infecciones por cocos grampositivos en el paciente crítico

In recent years, an increment of infections caused by gram-positive cocci has been documented in nosocomial and hospital-acquired infections. In diverse countries, a rapid development of resistance to common antibiotics against gram-positive cocci has been observed. This situation is exceptional in Spain but our country might be affected in the near future. New antimicrobials active against these multi-drug resistant pathogens are nowadays available. It is essential to improve our current knowledge about pharmacokinetic properties of traditional and new antimicrobials to maximize its effectiveness and to minimize toxicity. These issues are even more important in critically ill patients because inadequate empirical therapy is associated with therapeutic failure and a poor outcome. Experts representing two scientific societies (Grupo de estudio de Infecciones en el Paciente Critico de la SEIMC and Grupo de trabajo de Enfermedades Infecciosas de la SEMICYUC) have elaborated a consensus document based on the current scientific evidence to summarize recommendations for the treatment of serious infections caused by gram-positive cocci in critically ill patients.

Burden of methicillin-resistant Staphylococcus aureus: focus on clinical and economic outcomes

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major public concern. Hospital-acquired MRSA rates have steadily increased over the past 25 years, and the bacterial strain is making inroads to the community. The morbidity and mortality burden of MRSA infection is compounded by delayed or inappropriate antibiotic treatment, taking a toll on health care resources that are already stretched thin. Vancomycin has historically been the drug of choice for this pathogen because its broad spectrum can address the multidrug resistance of most MRSA infections. Despite its sustained in vitro microbiologic inhibitory activity, researchers are beginning to question the continued utility of vancomycin for MRSA infections. Evidence against vancomycin is most notable with regard to nosocomial pneumonia and skin and soft tissue infections. In addition, because vancomycin must be administered intravenously, patients typically require prolonged hospitalization, which further increases the cost of MRSA treatment and exposes patients to additional nosocomial infections. Recent studies have shown that antibiotics with good bioavailability, such as linezolid, can be given orally to facilitate early hospital discharge, thus alleviating the economic burden of MRSA infections. Several agents have been developed over the past decade that have excellent in vitro activity against MRSA. Further studies are needed to determine if these drugs can better eradicate MRSA than vancomycin and remedy the adverse outcomes frequently observed with this organism.

Treatment of hospital-acquired pneumonia caused by methicillin-resistant Staphylococcus aureus

Nosocomial pneumonia and ventilator-assisted pneumonia may be polymicrobial and can be caused by a wide spectrum of pathogens. Potentially multidrug-resistant microorganisms often represent the 'core' pathogens of the most severe infections. Among Gram-positive pathogens, methicillin-resistant Staphylococcus aureus (MRSA) plays a key role, mainly in mechanically ventilated patients or in patients with specific risk factors. The mainstay of treatment for MRSA pneumonia has been glycopeptide antibiotics, i.e. vancomycin and, to a lesser extent, teicoplanin. However, owing to its insufficient penetration into lung compartments, vancomycin may result in therapeutic failure or slow clinical responses. Moreover, vancomycin serum levels must be monitored in order to minimise nephrotoxicity and to maximise the concentration in the lung. Finally, the emergence of staphylococci isolates with reduced susceptibility to vancomycin suggests that glycopeptides should no longer be considered as first-line antibacterial agents for Gram-positive lung infections. Among new therapeutic options, linezolid may be an appropriate choice for MRSA pulmonary infections owing to its good pharmacokinetic profile in the lung and its acceptable tolerability, especially in patients with renal insufficiency or in those receiving other nephrotoxic agents. However, to contain the increasing emergence of drug resistance among hospitalised patients, these novel antimicrobial agents should be used judiciously, restricting their use to patients not responsive to, or intolerant of, glycopeptides. Other new drugs under development appear to be promising and deserve further evaluation.

Ventilator-associated pneumonia: breaking the vicious circle of antibiotic overuse

OBJECTIVE

To assess the rate of appropriateness of empirical antimicrobial therapy for ventilator-associated pneumonia, to evaluate de-escalation in patients with ventilator-associated pneumonia treated according to local pathway, and to identify the bacteria responsible for recurrence of ventilator-associated pneumonia.

DESIGN

Prospective observational study during a 36-month period.

SETTING

Medical-surgical intensive care unit of a university hospital.

PATIENTS

One hundred and fifteen patients hospitalized in an intensive care unit developing ventilator-associated pneumonia with positive cultures. The patients with ventilator-associated pneumonia were treated with limited-spectrum antibiotics (i.e., without activity against Pseudomonas aeruginosa) if they had no prior hospitalization (within 21 days) or prior administration of antibiotics (within 10 days). Quantitative cultures obtained by bronchoscopy or tracheal aspiration were used to reassess empirical therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A limited-spectrum therapy was used in 79 patients (69%). Empirical antimicrobial therapy was appropriate in 100 patients (85%). The mortality rate was significantly higher in the patients in whom empirical therapy was inappropriate than in those in whom treatment was appropriate (47 vs. 20%, p=.04). De-escalation was done in respectively 26% and 72% of patients with early- and late-onset ventilator-associated pneumonia, whereas treatment was escalated in 27 patients (23%). Ventilator-associated pneumonia episodes were recurrent in 22 cases, including eight episodes due to high-risk bacteria.

CONCLUSIONS

A rational empirical antimicrobial therapy for ventilator-associated pneumonia using limited-spectrum antibiotics is possible if local ecology and patient medical history and clinical status are considered. In addition, de-escalation is feasible in 42% of patients. This integrative approach may reduce the emergence of resistant bacteria, which in turns reduces the need for broad-spectrum antibiotics, breaking the vicious circle of antibiotic overuse.

Risk factors for death due to nosocomial infection in intensive care unit patients: findings from the Krankenhaus Infektions Surveillance System

OBJECTIVE

To determine risk factors for death among patients with nosocomial pneumonia and patients with primary bloodstream infections (BSI) in intensive care units (ICUs).

DESIGN

Prospective cohort study.

SETTING

Data collected from January 1997 through June 2003 from ICUs registered with the Krankenhaus Infektions Surveillance System in Germany.

PATIENTS

A total of 8,432 patients with nosocomial pneumonia from 202 ICUs and 2,759 patients with nosocomial primary BSI from 190 ICUs.

METHODS

The following risk factors were considered in the analysis: age, sex, time in the ICU before onset of infection, type of ICU, type and size of hospital, intubation, central venous catheter use, total parenteral nutrition, and type of pathogen.

RESULTS

A total of 750 patients (8.9%) with nosocomial pneumonia and 302 patients (10.9%) with nosocomial primary BSI died. Multiple logistic regression analysis identified treatment in a medical or surgical ICU (odds ratio [OR], 1.55 [95% confidence interval {CI}, 1.32-1.82]) or a hospital with more than 1,000 beds (OR, 2.14 [95% CI, 1.81-2.56]), age older than 65 years (OR, 1.54 [95% CI, 1.31-1.81]), and infection with methicillin-resistant Staphylococcus aureus (OR, 2.39 [95% CI, 1.81-3.12]) or multidrug-resistant Pseudomonas aeruginosa (OR, 3.00 [95% CI, 1.90-4.63]) as independent determinants of death from nosocomial pneumonia. Age older than the median of 63 years (OR, 1.44 [95% CI, 1.12-1.86]) and methicillin-resistant S. aureus as the causative agent (OR, 2.98 [95% CI, 1.81-5.82]) were both associated with increased mortality from primary BSI. The types of infecting pathogens, particularly those resistant to multiple drugs, were also strong outcome predictors among ICU patients.

CONCLUSIONS

The study results underline the need for further investigations of the role of antimicrobial resistance in the outcome of patients with nosocomial pneumonia and patients with primary BSI.

Management of ventilator-associated pneumonia caused by multiresistant bacteria

PURPOSE OF REVIEW

The inappropriate choice of antibiotics (in nearly one third of episodes) is the most important risk factor for death. Traditionally, a narrow-spectrum drug was used first, and the most potent drugs were reserved for subsequent use.

RECENT FINDINGS

As multidrug resistance increases in the intensive care unit in patients treated for nosocomial pneumonia, costs, mortality, and morbidity are rising. Although methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii are frequently considered together, they have different virulence, risk factors and susceptibilities, requiring different antimicrobial choices. Assessment of clinical resolution should be differentiated in the presence of acute lung injury. In the absence of biochemical markers, oxygenation and core temperature should guide therapeutic decisions.

SUMMARY

As ventilator-associated pneumonia increases, empiric therapy should be based on local pathogen etiology and antibiotic resistant patterns. A new approach to consider is to start with a high-dose, broad-spectrum antibiotic and then tailor the individual therapy based on microbiological results and clinical resolution. With the use of broad-spectrum antibiotics available in empiric therapy tailored after reassessment of the patient, there is hope for reducing costs, length of stay and mortality whereas the emergence of resistance will be minimized.

Early predictors for infection recurrence and death in patients with ventilator-associated pneumonia

OBJECTIVE

Early recognition of predictors of unfavorable evolution of ventilator-associated pneumonia (VAP) might prompt therapeutic measures that might improve outcome. The objective of this study was to describe resolution of VAP variables and to determine early predictors of VAP recurrence and death.

DESIGN AND SETTING

Description of the natural course of VAP resolution and multivariable analyses of predictors of VAP recurrence and death by day 28 after VAP onset based on the 401 patients included in the PNEUMA trial, a multiple-center, randomized study comparing 8 vs. 15 days of antibiotics for microbiologically proven VAP. Every patient included in that trial had received appropriate empirical antibiotics.

MEASUREMENTS AND MAIN RESULTS

By day 28 after VAP onset, 27% of patients had VAP recurrence and 18% had died. On day 8 after VAP onset, predictors of VAP recurrence included intensive care unit admission Simplified Acute Physiology Score II (odds ratio [OR], 1.02), radiologic score (OR, 1.17), temperature (OR, 1.34), nonfermenting Gram-negative bacilli (OR, 2.00) or methicillin-resistant Staphylococcus aureus (OR, 2.50) as pathogens responsible for VAP, and mechanical ventilation dependency (OR, 2.08). Day 8 predictors of 28-day death were age (OR, 1.06), female sex (OR, 2.30), Sepsis-Related Organ Failure Assessment score (OR, 1.26), and nonfermenting Gram-negative bacilli (OR, 2.83) as pathogens responsible for VAP. However, the duration of antimicrobial therapy (8 vs. 15 days) was not associated with any of the studied adverse outcomes.

CONCLUSIONS

For patients benefiting from appropriate empirical antibiotics for VAP, early predictors of infection recurrence or death included demographic characteristics, such as age or female sex, disease severity at VAP onset, nonfermenting Gram-negative bacilli or methicillin-resistant S. aureus as VAP-causative pathogens, prolonged mechanical ventilation dependency, persistent fever, and severity of lung injury. Future studies should attempt to determine whether specific diagnostic or therapeutic strategies could markedly improve VAP outcomes when early criteria for treatment failure are present.