Value of noninvasive studies in community-acquired pneumonia

Infections Are Leading Cause of In-Hospital Mortality in Indian Patients With Inflammatory Myopathy

OBJECTIVES

We explored causes of in-hospital mortality in patients with inflammatory myositis at a tertiary care center in Northern India.

METHODS

Records of adults and children diagnosed with dermatomyositis (DM), polymyositis, or anti-synthetase syndrome (ASSD) who died between 2000 and 2018 were reviewed, and causes of death were determined.

RESULTS

Of the 38 patients, 20 had DM (including 2 clinically amyopathic DM), 4 juvenile DM, 12 polymyositis, whereas 2 had ASSD. Median age at death was 42.0 (interquartile range, 32.8-52.5) years. Median disease duration at death was 18.5 (interquartile range, 2.0-23.5) months. Twenty-four (63.2%) had infection as the primary cause of death. Other causes of death included pharyngeal muscle weakness and aspiration (n = 6), myocarditis (n = 2), respiratory failure (n = 2), cerebral bleed (n = 2), and pulmonary embolism (n = 1). One patient succumbed to rapidly progressive interstitial lung disease, whereas another patient with ASSD died following respiratory distress after rituximab infusion. In post hoc analysis, although thrombocytopenia appeared to be a risk factor for early mortality (odds ratio, 13.3; 95% confidence interval, 1.4-123.8; p = 0.01), this was not supported in the multivariate analysis.

CONCLUSIONS

Infections are the most common cause of in-hospital mortality in myositis patients.

Targets for antibiotic and healthcare resource stewardship in inpatient community-acquired pneumonia: a comparison of management practices with National Guideline Recommendations

PURPOSE

Community-acquired pneumonia (CAP) is the most common infection leading to hospitalization in the USA. The objective of this study was to evaluate management practices for inpatient CAP in relation to Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) guidelines to identify opportunities for antibiotic and health care resource stewardship.

METHODS

This was a retrospective cohort study of adults hospitalized for CAP at a single institution from 15 April 2008 to 31 May 2009.

RESULTS

Of the 209 patients with CAP who presented to Denver Health Medical Center during the study period and were hospitalized, 166 (79 %) and 43 (21 %) were admitted to a medical ward and the intensive care unit (ICU), respectively. Sixty-one (29 %) patients were candidates for outpatient therapy per IDSA/ATS guidance with a CURB-65 score of 0 or 1 and absence of hypoxemia. Sputum cultures were ordered for 110 specimens; however, an evaluable sample was obtained in only 49 (45 %) cases. Median time from antibiotic initiation to specimen collection was 11 [interquartile range (IQR) 6-19] h, and a potential pathogen was identified in only 18 (16 %) cultures. Blood cultures were routinely obtained for both non-ICU (81 %) and ICU (95 %) cases, but 15 of 36 (42 %) positive cultures were false-positive results. The most common antibiotic regimen was ceftriaxone + azithromycin (182, 87 % cases). Discordant with IDSA/ATS recommendations, oral step-down therapy consisted of a new antibiotic class in 120 (66 %), most commonly levofloxacin (101, 55 %). Treatment durations were typically longer than suggested with a median of 10 (IQR 8-12) days.

CONCLUSIONS

In this cohort of patients hospitalized for CAP, management was frequently inconsistent with IDSA/ATS guideline recommendations, revealing potential targets to reduce unnecessary antibiotic and healthcare resource utilization.

Clinical features predicting failure of pathogen identification in patients with community acquired pneumonia

Community acquired pneumonia (CAP) is caused by a variety of microorganisms. By identifying patients at risk for failure of pathogen identification, it is possible to make an early decision on the extent of diagnostic procedures to be performed. This is especially important in patients with severe CAP. The aim of this study was to identify these patients by using clinical and laboratory features. In 201 patients hospitalized for CAP, clinical and laboratory variables were collected. Pathogen identification was performed by culture of sputum and blood, urine antigen tests, polymerase chain reaction of sputum, serological testing and viral culture of the pharynx. In 128 patients a respiratory microorganism was identified. In both univariate and multivariate analysis, failure of pathogen identification was predicted by pre-hospital antibiotic therapy, a medical history of hypertension and a low C-reactive protein. We conclude that patients with pre-hospital antibiotic therapy, a medical history of hypertension and a relatively low C-reactive protein are at risk for failure of pathogen identification. These predictors should be confirmed in a larger population. Invasive testing in high-risk patients with CAP in the presence of these predictors should be considered at an early phase of hospitalization.

Differences in the etiology of community-acquired pneumonia according to site of care: A population-based study

BACKGROUND

A few population-based studies assessing the etiology of community-acquired pneumonia in both hospitalized and ambulatory patients, with special emphasis on the etiologic role of viral infections, have been reported. The purpose of this study was to assess microbiological differences according to initial site of care in patients with community-acquired pneumonia.

METHODS

We studied 496 patients > 14 years of age collected from the study samples of three population-based studies carried out in the same geographical area ("Maresme" region in the Mediterranean coast in Barcelona, Spain) with the same methodology over an 8-year period (1987-1995).

RESULTS

Fifty-six percent of patients were hospitalized and 44% were treated at home. Of the 474 patients with etiological evaluation, 195 patients had an identifiable etiology (overall diagnostic yield 41%). Streptococcus pneumoniae was the most common causative organism. Viral infection was diagnosed in 26.5% of hospitalized patients vs. 13.2% of ambulatory patients (P=0.03). Twenty-five percent of the 68 patients with documented etiology treated at home had Chlamydia pneumoniae infection compared with 14.3% of those treated in the hospital. Ten percent of hospitalized patients had pneumonia caused by two pathogens compared with 9.7% of ambulatory patients. The association of viruses and bacteria was the most frequent cause of dual infection (79% inpatients, 67% outpatients).

CONCLUSIONS

This study has provided information on etiology of community-acquired pneumonia in hospitalized patients and in patients treated at home. A considerable proportion of patients had viral pneumonia, frequently requiring hospital admission for inpatient care.

Diagnostic test for etiologic agents of community-acquired pneumonia

Diagnostic tests for the detection of the etiologic agent of pneumonia are neither recommended nor done for most outpatients with CAP (Table 4).Most of these patients have no clear diagnosis but seem to do well with empiric antibiotic treatment, which often costs less than the diagnostic tests. For hospitalized patients, a pre-treatment blood culture and an expectorated sputum gram stain and culture should be done. Testing for Legionella spp is appropriate in hospitalized patients, especially those who are seriously ill. New tests that merit use in selected patients are the urinary antigen assay for S pneumoniae and the PCR test for L pneumophila. Anticipated developments in the near future are PCR tests for detection of C pneumoniae and M pneumoniae.

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.

H. influenzae Consortium: integrative study of H. influenzae-human interactions

Developments in high-throughput analysis tools coupled with integrative computational techniques have enabled biological studies to reach new levels. The ability to correlate large volumes of diverse data types into cohesive models of organism function has spawned a new systematic approach to biological investigation. The creation of a new consortium has been proposed to investigate a single organism utilizing these comprehensive approaches. The Haemophilus influenzae Consortium (HIC) would be comprised of five laboratories, each providing separate and complementary areas of expertise in the study of Haemophilus influenzae (HI). The 5-year study proposes to develop coherent models of HI, both as a stand-alone organism, and more importantly, as a human pathogen. Studies in growth condition specificity followed by genomic, metabolic, and proteomic experimentation will be combined and integrated through computational and experimental analyses to form dynamic and predictive models of HI and its responses. Data from the HIC will allow greater understanding of cellular behavior, pathogen-host interactions, bacterial infection, and provide future scientific endeavors with a template for studies of other pathogens.

Laboratory diagnosis of community-acquired lower respiratory tract infection

This article has focused on the evaluation of outpatients with lower respiratory illness. In large part, the need for microbiological work-up is host-dependent. Healthy patients usually do well, and laboratory data are often unnecessary. The abnormal host requires a different approach and, in general, the more compromised the host, the more aggressive the laboratory evaluation. A renal transplant patient with respiratory symptoms often follows the dictum that "common things happen commonly;" however, the clinician needs that extra level of assurance in this case. Some transplant patients may have respiratory illness caused by strongyloidiasis. Cystic fibrosis is another example of the need for a more comprehensive laboratory evaluation. Specialized selective media and additional susceptibility studies may be needed to evaluate isolates associated with exacerbation of symptoms in these patients. The clinical laboratory should be forewarned of any materials coming from invasive diagnostic techniques, so they can prepare and offer useful advice regarding specimens, transport, and follow-up. Microbiological laboratories are often most knowledgeable regarding what type of testing is appropriate. Direct communication with the laboratory is essential to assure the best patient care.

Diagnosis and management of respiratory tract infections for the primary care physician

Respiratory tract infections cause nearly half of deaths owing to infectious disease in the United States. This article has discussed the management of several common respiratory tract infections, with an emphasis on appropriate diagnosis and use of antimicrobial agents. Understanding the cause of various respiratory tract infections enables primary care physicians to avoid unnecessary antibiotic use, decreasing adverse effects owing to medications and preventing the rise in antimicrobial resistance.

Importance of atypical pathogens of community-acquired pneumonia

The atypical clinical presentation of patients with community-acquired pneumonia (CAP) was first recognized and reported by astute clinicians 50 years ago. The cause of pneumonia in this group eventually was shown to be Mycoplasma pneumoniae. More recently, Chlamydia pneumoniae also has been recognized as a cause of CAP. Legionella has been lumped together with M. pneumoniae and C. pneumoniae because of its antimicrobial susceptibility pattern. This group of organisms is susceptible to the macrolides, tetracycline, and the newer fluoroquinolones. However, Legionnaires' disease frequently presents a more acute clinical picture than either mycoplasmal or chlamydial infections. Recent data suggest that in the Medicare population hospitalized with pneumonia, morbidity and mortality can be decreased if initial therapy includes coverage for atypical pathogens (i.e., macrolides or fluoroquinolones). Unfortunately, few studies use culture methodology for atypical pathogens. Future studies of the efficacy of macrolide or fluoroquinolone therapy for CAP should include aggressive diagnostic studies for M. pneumoniae, C. pneumoniae, and Legionella species.

Severe pneumonia. When and why to hospitalize

Relatively simple objective criteria are now available to predict which patients are at risk for bad outcomes from community-acquired pneumonia. In general, these include older patients and those with certain coexisting illnesses (especially neoplastic disease) or findings of altered mental status, hypotension, severe tachycardia, tachypnea, fever, acidemia, azotemia, hypoxemia, hyperglycemia, anemia, or hyponatremia. The major causes of severe pneumonia are S pneumoniae, H influenzae, and L pneumophila. Less common causes include mixed aerobic and anaerobic mouth flora, as well as M pneumoniae, C pneumoniae, gram-negative bacilli, and S aureus. Specific diagnosis is hampered by a lack of reliable diagnostic tests, but Gram's stain of expectorated sputum and cultures of sputum and blood may occasionally be helpful. Many empirical treatment regimens have been recommended, including those of the American Thoracic Society and the Infectious Diseases Society of America, which are reviewed here. It is hoped that better diagnostic tools will permit future targeting of microbes with narrow-spectrum therapy to diminish the risk of selection of resistant strains with empirical regimens.