Impact of invasive strategy on management of antimicrobial treatment failure in institutionalized older people with severe pneumonia

100 years of respiratory medicine: pneumonia

In this review, we aim to lead the readers through the historical highlights of pathophysiological concepts and treatment of pneumonia. Understanding the aetiology, the risk factors and the pathophysiology influenced our management approaches to pneumonia. Pneumonia is still associated with significant morbidity and mortality, presents in a variety of healthcare settings and imposes a considerable cost to healthcare services. Guidelines have been issued by international and national scientific societies in order to spread the scientific knowledge on this important disease and to improve its management.

Clinical and hemostatic responses to treatment in ventilator-associated pneumonia: role of bacterial pathogens

OBJECTIVE

To determine pathogen-specific kinetic changes in the alveolar procoagulant (PC) activity, tissue factor (TF), and tissue factor pathway inhibitor (TFPI) expression during the course of ventilator-associated pneumonia (VAP) and to assess the relationship between clinical resolution, intra-alveolar bacterial eradication, and restoration of hemostatic balance.

DESIGN

Prospective, multiple-center study in a cohort of VAP patients.

SETTING

Two university-affiliated intensive care units.

PATIENTS

Thirty-five patients with microbiologically documented VAP who received adequate antimicrobial coverage and 13 controls.

INTERVENTIONS

Nonbronchoscopic bronchoalveolar lavage was performed at the onset of VAP and on days 4 and 8 after initiation of antibiotic therapy. Samples were assayed for PC, TF, TFPI, and thrombin-antithrombin complex (TATc). The corresponding Clinical Pulmonary Infection Score (CPIS) was collected simultaneously.

MEASUREMENTS AND MAIN RESULTS

Isolated pathogens included Pseudomonas aeruginosa (n=13), methicillin-resistant Staphylococcus aureus (MRSA) (n=8), methicillin-sensitive S. aureus (MSSA) (n=7), and Escherichia coli (n=7). Although PC activity and TF were increased among the various pathogens at the onset of VAP, the levels of those with P. aeruginosa remained elevated at the end of treatment compared with controls and other etiological agents. TFPI levels were elevated for the duration of the study for all pathogens. A universal increase in TATc was noted at the onset of VAP, but the difference among the group of pathogens was significant at days 4 and 8 posttherapy. Despite the persisting hemostatic imbalance and incomplete intra-alveolar eradication of P. aeruginosa at end of therapy, the CPIS fell comparably at each time point irrespective of the etiological agents.

CONCLUSIONS

Alveolar activation of the TF-dependent pathway may be species-specific in VAP and may not be adequately balanced by TFPI. The disparity between clinical response and eradication of P. aeruginosa from the intra-alveolar space suggests the need for biological markers to guide response to therapy.

Guidelines for the management of adults with health care-associated pneumonia: implications for nursing facility residents

OBJECTIVE

To review the implications for nursing facility residents of the 2005 American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) guidelines for the Management of Adults with Health Care-Associated Pneumonia.

DATA SOURCE

A MEDLINE/PUBMED search (1986-February 2006) was conducted to identify pertinent studies of health care associated pneumonia acquired in the nursing facility setting (formerly called nursing home-acquired pneumonia) in the English language. Additional references were obtained from the bibliographies of these studies.

STUDY SELECTION AND DATA EXTRACTION

All studies evaluating any aspect of nursing home-acquired pneumonia.

DATA SYNTHESIS

Careful review of these guidelines will reveal a failure of the ATS/IDSA committee members to review the large published database available in the field of nursing home-acquired pneumonia. In addition, the committee was devoid of representation from experts in this field. As a result, these guidelines are applicable only to nursing facility residents admitted to the hospital. For the vast majority of nursing facility residents, these guidelines are problematic. The use of invasive means to acquire respiratory tract secretions for culture and susceptibility testing in the nursing facility setting is just not possible. Few facilities are able to manage residents with the two-, three-, or four-drug combination intravenous therapies recommended. As a result of these realities, all residents of nursing facilities with suspected pneumonia would be forced into hospital for diagnostic workup and at least initial empiric therapy if the guidelines were followed "to the letter." The guidelines do not even discuss the issue of site of treatment and how to select residents for outpatient (i.e., infacility) versus inpatient (i.e., in-hospital) management. Infacility management mandated by advanced directives is not even considered by the guidelines.

CONCLUSION

There does exist a database upon which the clinician can make informed decisions about likely pathogens, the probability that the resident actually has bacterial pneumonia, objective parameters suggesting the need for hospitalization for initial management, and guidance on when to initiate antimicrobial therapy, and which agent(s) to use. These issues are summarized here, and alternative, evidence-based, practical recommendations for the management of nursing home-acquired pneumonia are outlined.

[Contribution of microbiological investigations to the diagnosis of lower respiratory tract infections]

The diagnosis of community-acquired pneumonia is usually based on clinical and radiological criteria. The identification of a causative organism is not required for the diagnosis. Although numerous microbiological techniques are available, their sensitivity and specificity are not high enough to guide first-line antimicrobial therapy. Consequently, this treatment remains most often empiric. If the causative organism is identified, the antimicrobial treatment is adapted. Sputum analysis may be proposed as a diagnostic tool for patients with an acute exacerbation of chronic obstructive pulmonary disease, in specific cases (prior antibiotherapy, hospitalization, failure of the empiric antimicrobial treatment).

What is healthcare-associated pneumonia, and how should it be treated?

PURPOSE OF REVIEW

In contrast to patients at risk for hospital-acquired pneumonia or mechanically ventilated patients at risk for ventilator-associated pneumonia, healthcare-associated pneumonia is a relatively new clinical entity that includes a spectrum of adult patients who have close association with acute care hospitals or reside in chronic care settings that increase their risk for pneumonia caused by multi-drug-resistant bacteria. Multi-drug-resistant pathogens include methicillin-resistant Staphylococcus aureus and Gram-negative bacilli, such as Pseudomonas aeruginosa, extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, and Acinetobacter species. New guidelines for the management and prevention of hospital-acquired pneumonia, ventilator-associated pneumonia and healthcare-associated pneumonia from the American Thoracic Society and the Infectious Diseases Society of America were published in 2005 and are highlighted in this article.

RECENT FINDINGS

Recent data indicate that types of multi-drug-resistant pathogens may vary in different healthcare settings, and that individuals infected with multi-drug-resistant pathogens are more likely to receive inappropriate initial antibiotic therapy, which may result in poorer outcomes in terms of patient morbidity, mortality and increased length of hospital stay.

SUMMARY

This review highlights key points in the new recommendations and principles for initiating, de-escalating and stopping antibiotic therapy in individuals with healthcare-associated pneumonia. Widespread implementation of these guidelines is needed in healthcare institutions in order to reduce patient morbidity, mortality, and healthcare costs.

Guidelines for the Treatment of Community-acquired Pneumonia

RATIONALE

Some studies highlight the association of better clinical responses with adherence to guidelines for empiric treatment of community-acquired pneumonia (CAP), but little is known about factors that influence this adherence.

OBJECTIVES

Our objectives were to identify factors influencing adherence to the guidelines for empiric treatment of CAP, and to evaluate the impact of adherence on outcome.

METHODS

We studied 1,288 patients with CAP admitted to 13 Spanish hospitals. Collected variables included the patients' clinical and demographic data, initial severity of the disease, antibiotic treatment, and specialty and training status of the prescribing physician.

MEASUREMENTS AND MAIN RESULTS

Adherence to guidelines was high (79.7%), with significant differences between hospitals (range, 47-97%) and physicians (pneumologists, 81%; pneumology residents, 84%; nonpneumology residents, 82%; other specialists, 67%). The independent factors related to higher adherence were hospital, physician characteristics, and initial high-risk class of Fine, whereas admission to intensive care unit decreased adherence. Seventy-four patients died (6.1%), and treatment failure was found in 175 patients (14.2%). After adjusting for Fine risk class, adherence to the guidelines was found protective for mortality (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.3-0.9) and for treatment failure (OR, 0.65; 95% CI, 0.5-0.9). Treatment prescribed by pneumologists and residents was associated with lower treatment failure (OR, 0.6; 95% CI, 0.4-0.9).

CONCLUSIONS

Adherence to guidelines mainly depends on the hospital and the specialty and training status of prescribing physicians. Nonadherence was higher in nonpneumology specialists, and is an independent risk factor for treatment failure and mortality.

Pneumonia in the Nursing Home

Pneumonia syndromes may be caused by infection or the aspiration of food, acid, or particulate material. Antibiotic-resistant organisms or recurrent aspiration should be considered if the response to treatment is poor. Clinicians should consider discontinuing antibiotics if the resident's status rapidly returns to baseline after a noninfectious macro-aspiration event. The natural history of this process, however, is not well characterized. Diagnostic procedures including sputum gram stain, culture, and urinary antigen testing should be pursued to diagnose pathogens not covered by empiric therapy or to focus therapy with narrow spectrum agents. Sources of aspiration, including pharyngeal dysphagia, periodontal disease, and gastric regurgitation, should be identified and treated in hopes of preventing recurrence.

[Guidelines for the management of community pneumonia in adult who needs hospitalization]

Community acquired pneumonia is still an important health problem. In Spain the year incidence is 162 cases per 100,000 inhabitants with 53,000 hospital admission costing 115 millions of euros per year. In the last years there have been significant advances in the knowledge of: aetiology, diagnostic tools, treatment alternatives and antibiotic resistance. The Spanish Societies of Intensive and Critical Care (SEMICYUC), Infectious Diseases and Clinical Microbiology (SEIMC) and Pulmonology and Thoracic Surgery (SEPAR) have produced these evidence-based Guidelines for the management of community acquired pneumonia in Adults. The main objective is to help physicians to make decisions about this disease. The different points that have been developed are: aetiology, diagnosis, treatment and prevention.

Nonresponses and treatment failures with conventional empiric regimens in patients with community-acquired pneumonia

Although most patients with suspected CAP respond to empiric therapy,a small number of patients do not respond in the expected fashion. Age and underlying comorbid conditions have a strong influence on the course of illness. Less common causes of treatment failures include overwhelming infection, antimicrobial resistance, and misdiagnosis. It is a common practice for empiric antimicrobial treatment of CAP to be initiated without microbiologic studies. Clinicians carefully should observe these patients for unusual or slow responses and should be ready to pursue a more extensive search for the cause of treatment failure.

Healthcare-associated pneumonia in adults: management principles to improve outcomes

Guidelines for Management of HAP were developed jointly by the ATS and IDSA in 2004. These guidelines were designed to improve patient outcomes and to decrease the emergence of MDR pathogens (see Fig. 1).Principles include early initiation of appropriate and adequate antibiotic therapy after cultures of blood and sputum are obtained. Quantitative distal airway sampling by bronchoscopy provides greater diagnostic specificity for VAP: in one randomized study, improved outcomes were noted, compared with clinical diagnosis with qualitative endotracheal aspirates. Higher doses of initial, empiric antibiotics also are recommended. Assessment of the patient's clinical response to empiric antibiotics should be correlated with microbiologic results to streamline, de-escalate, or stop unnecessary anti-biotic treatment. Duration of therapy for uncomplicated HAP should be limited to 7 days followed by close monitoring for relapse after cessation of antibiotics. The authors suggest that prevention strategies target modifiable short- and long-term risk factors. They also advocate the use of a multidisciplinary team that is dedicated to the treatment and prevention of HCAP and the basic principle of the modern Hippocratic Oath: "I will prevent disease whenever I can, for prevention is preferable to cure."

Diagnosis of infection in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for the diagnosis of infection in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSIONS

Obtaining a precise bacteriological diagnosis before starting antibiotic therapy is, when possible, of paramount importance for the success of therapeutic strategy during sepsis. Two to three blood cultures should be performed, preferably from a peripheral vein, without interval between samples to avoid delaying therapy. A quantitative approach is preferred in most cases when possible, in particular for catheter-related infections and ventilator-associated pneumonia. Diagnosing community-acquired pneumonia is complex, and a diagnostic algorithm is proposed. Appropriate samples are indicated during soft tissue and intraabdominal infections, but cultures obtained through the drains are discouraged.

Procoagulant and fibrinolytic activity in ventilator-associated pneumonia: impact of inadequate antimicrobial therapy

OBJECTIVE

To determine the homeostatic balance of patients with ventilator-associated pneumonia (VAP) with respect to the adequacy of antimicrobial therapy.

DESIGN AND SETTING

Descriptive observational study in a 12-bed medical intensive care unit in a university-affiliated hospital.

PATIENTS

Twenty-nine patients with VAP documented by quantitative culture of bronchoalveolar secretions and a control group of eight mechanically ventilated patients.

METHODS

Serial bronchoalveolar lavage fluid (BALF) samples were assayed for prothrombin activation fragment (F1+2), thrombin-antithrombin (TAT) complex, fibrinolytic activity, urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor type 1 (PAI-1) on days 1, 4, and 7 after VAP onset.

RESULTS

Pathogens isolated from patients with inadequate empirical antimicrobial coverage included methicillin-resistant Staphylococcus aureus (n=2), Pseudomonas aeruginosa (n=4), and Acinetobacter baumannii (n=1). Compared to those who received adequate antibiotic therapy, TAT, F1+2, and PAI-1 levels increased while u-PA levels remained unchanged. Despite antibiotic adjustment on day 4, TAT levels remained elevated in those who lacked adequate antimicrobial coverage and were significantly correlated with PaO(2)/FIO(2). The procoagulant activity was accompanied by a local depression of fibrinolytic capacity that was attributed mainly to increased BALF PAI-1 levels. Nonsurvivors showed significantly higher levels of TAT and PAI-1 than survivors. No significant correlation between the bacterial burden and the homeostatic derangements was documented.

CONCLUSIONS

The lung inflammatory response seems to promulgate a local procoagulant activity associated with hypoxemia in those with inadequate antibiotic therapy. The homeostatic derangement seems to be independent of the lung bacterial burden.

Differential regulation of membrane CD14 expression and endotoxin-tolerance in alveolar macrophages

CD14 is important in the clearance of bacterial pathogens from lungs. However, the mechanisms that regulate the expression of membrane CD14 (mCD14) on alveolar macrophages (AM) have not been studied in detail. This study examines the regulation of mCD14 on AM exposed to Escherichia coli in vivo and in vitro, and explores the consequences of changes in mCD14 expression. The expression of mCD14 was decreased on AM exposed to E. coli in vivo and AM incubated with lipopolysaccharide (LPS) or E. coli in vitro. Polymyxin B abolished LPS effects, but only partially blocked the effects of E. coli. Blockade of extracellular signal-regulated kinase pathways attenuated LPS and E. coli-induced decrease in mCD14 expression. Inhibition of proteases abrogated the LPS-induced decrease in mCD14 expression on AM and the release of sCD14 into the supernatants, but did not affect the response to E. coli. The production of tumor necrosis factor-alpha in response to a second challenge with Staphylococcus aureus or zymosan was decreased in AM after incubation with E. coli but not LPS. These studies show that distinct mechanisms regulate the expression of mCD14 and the induction of endotoxin tolerance in AM, and suggest that AM function is impaired at sites of bacterial infection.

Bronchoscopic microsampling method for measuring drug concentration in epithelial lining fluid

Direct measurement of the concentration of antimicrobial agents in bronchial epithelial lining fluid (ELF) would allow for a more informed approach to appropriate dosing of antimicrobial agents for respiratory tract infections. In this study, we determined the time versus concentration profile in ELF after an oral administration of levofloxacin, using recently developed bronchoscopic microsampling probes. These probes could be repeatedly and safely inserted through the fiberoptic bronchoscope in normal healthy volunteers. The concentration of levofloxacin in ELF was 43.4% of the corresponding serum value at 1 hour, reached the same level at 2 hours, decreased in a similar manner as that in serum, and returned to undetectable levels at 24 hours. It exceeded minimal inhibitory concentrations of Staphylococcus aureus (0.25 microg/ml), Klebsiella species (0.5 microg/ml), and Haemophilus influenzae (0.06 microg/ml) after 6 hours. The experimental procedure was well tolerated, and no complications were observed. In conclusion, bronchoscopic microsampling is a feasible and promising method for measuring antimicrobial concentrations in the target sites of respiratory tracts directly and repeatedly.

Microbiology of severe aspiration pneumonia in institutionalized elderly

We sought to investigate prospectively the microbial etiology and prognostic indicators of 95 institutionalized elders with severe aspiration pneumonia, and to investigate its relation to oral hygiene in using quantitative bronchial sampling. Data collection included demographic information, Activity of Daily Living, Plaque Index, antimicrobial therapy, and outcome. Out of the 67 pathogens identified, Gram-negative enteric bacilli were the predominant organisms isolated (49%), followed by anaerobic bacteria (16%), and Staphylococcus aureus (12%). The most commonly encountered anaerobes were Prevotella and Fusobacterium species. Aerobic Gram-negative bacilli were recovered in conjunction with 55% of anaerobic isolates. The Plaque Index did not differ significantly between the aerobic (2.2 +/- 0.4) and the anaerobic group (2.3 +/- 0.3). Functional status was the only determinant of the presence of anaerobic bacteria. Although seven cases with anaerobic isolates received initially inadequate antimicrobial therapy, six had effective clinical response. The crude mortality was 33% for the aerobic and 36% for the anaerobic group (p = 0.9). Stepwise multivariate analysis identified hypoalbuminemia (p < 0.001) and the burden of comorbid diseases (p < 0.001) as independent risk factors of poor outcome. In view of the rising resistance to antimicrobial agents, the importance of adding anaerobic coverage for aspiration pneumonia in institutionalized elders needs to be reexamined.