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Purpose: The objective of this study was to describe the diagnostic yield and safety of bronchoalveolar lavage (BAL) in the evaluation of pulmonary lesions in immunocompromised children., Methods: We conducted a systematic review of literature published during the past 20 years, searching Medline, Medline EPub, EMBASE, and Scopus. Studies included involved paediatric patients (<18 years) on treatment for an oncological diagnosis or other immune compromise who underwent BAL for evaluation of pulmonary lesions. Only English language publications were included., Results: In all, 272 studies were screened and 19 included. All were observational studies with moderate (11/19) or serious (8/19) risk of bias. BAL yielded a potential pathogen in 43% of cases (496/1156). Two papers reported improved diagnostic yield with early BAL (less than 3 days of presentation). A change in patient management after BAL was reported in 53% of cases (275/519). Adverse events were reported in 19% of cases following BAL (193/993) but were generally mild with no procedure-related mortality reported., Conclusion: BAL appears to be useful for evaluation of pulmonary lesions in immunocompromised children with generally acceptable safety, though included studies had at least moderate risk of bias. Future prospective studies may provide more definitive estimates of benefit, timing and risk of BAL in this population., (Copyright © 2020. Published by Elsevier Ltd.)

When children have a wet cough, it suggests the presence of secretions in their airways. This often has an infectious aetiology which is usually a self-limiting viral infection requiring no investigation or treatment. In those with acute wet cough it is, however, important to identify features suggestive of community acquired pneumonia or an inhaled foreign body as these causes require specific management. When there is chronic wet cough, the most common diagnoses are protracted bacterial bronchitis (PBB) and bronchiectasis. The relationship between these two conditions is complex as the development of bronchiectasis manifests as a clinical continuum in which the early features of which are indistinguishable from PBB. It is therefore important to identify PBB and chronic cough endotypes which are associated with an increased risk of bronchiectasis. This article offers a pragmatic approach to the investigation and treatment of children with wet cough. It is hoped this will limit unnecessary investigations whist aiding the prompt diagnosis of conditions needing treatment to reduce symptom burden and prevent further lung damage., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aetiology of community acquired pneumonia varies according to the region in which it is acquired. This review discusses those causes of CAP that occur in the tropics and might not be readily recognizable when transplanted to other sites. Various forms of pneumonia including the viral causes such as influenza (seasonal and avian varieties), the coronaviruses and the Hantavirus as well as bacterial causes, specifically the pneumonic form of Yersinia pestis and melioidosis are discussed., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Mortality in patients with community-acquired pneumonia (CAP) remains high despite improvements in treatment., Objective: To determine immunoglobulin levels in patients with CAP and impact on disease severity and mortality., Methodology: Observational study. Hospitalized patients with CAP were followed up for 30 days. Levels of immunoglobulin G (IgG) and subclasses, immunoglobulin A (IgA) and immunoglobulin M (IgM) were measured in serum within 24 hours of CAP diagnosis., Results: Three hundred sixty-two patients with CAP were enrolled -172 ward-treated and 190 intensive care unit-treated. Intensive care unit-treated patients had significantly lower values of IgG1, IgG2, IgG3 subclasses, and IgA than ward-treated patients. Thirty-eight patients died before 30 days. Levels of IgG2 were significantly lower in non-survivors than survivors (P=.004) and IgG2 <301 mg/dL was associated with poorer survival according to both the bivariate (hazard ratio 4.47; P<.001) and multivariate (HR 3.48; P=.003) analyses., Conclusions: Patients with CAP with IgG2 levels <301 mg/dL had a poorer prognosis and a higher risk of death. Our study suggests the usefulness of IgG2 to predict CAP evolution and to provide support measures or additional treatment., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Immunocompromised patients, especially those receiving treatment with corticosteroids and cytotoxic chemotherapy are at increased risk for developing Legionella pneumonia., Objective: The aim of this study was to determine clinical and radiographic characteristics of pulmonary infection due to Legionella in persons undergoing treatment for cancer and stem cell transplant (SCT) recipients., Methods: Retrospective review of Legionella cases at MSKCC over a fifteen-year study period from January 1999 and December 2013. Cases were identified by review of microbiology records., Results: During the study period, 40 cases of Legionella infection were identified; nine among these were due to non-pneumophila species. Most cases occurred during the summer. The majority [8/9, (89%)] of patients with non-pneumophila infection had underlying hematologic malignancy, compared to 18/31 (58%) with Legionella pneumophila infections. Radiographic findings were varied-nodular infiltrates mimicking invasive fungal infection were seen only among patients with hematologic malignancy and hematopoietic stem cell transplant (SCT) recipients and were frequently associated with non-pneumophila infections (50% vs 16%; P = 0.0594). All cases of nodular Legionella pneumonia were found incidentally or had an indolent clinical course., Conclusions: Legionella should be considered in the differential diagnosis of nodular lung lesions in immunocompromised patients, especially those with hematologic malignancy and SCT recipients. Most cases of nodular disease due to Legionella are associated with non-pneumophila infections., (Copyright © 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

Necrotising pneumonia remains an uncommon complication of pneumonia in children but its incidence is increasing. Pneumococcal infection is the predominant cause in children but Methicillin resistant Staphylococcus aureus (MRSA) and Panton-Valentine leukocidin (PVL) staphylococcal infection are also important causes of severe necrotising pneumonia. Clinical features of necrotic pneumonia are similar to those of an uncomplicated pneumonia except that the patient is clinically much more unwell and has usually failed to respond adequately to what would normally be considered as appropriate antibiotics. Pleural involvement is frequent. Initial management is similar to that for non-complicated pneumonia with careful attention to fluid balance and adequate analgesia required. Some patients will need intensive care support, particularly those with PVL-positive staphylococcal infection. Broad-spectrum antibiotics should be given intravenously, with the exact choice of agent informed by local resistance patterns. Pleural drainage is often required. Despite the severity of the illness, outcomes remain excellent with the majority of children making a full recovery., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Community-acquired pneumonia (CAP) occurs more often in early childhood than at almost any other age. Many microorganisms are associated with pneumonia, but individual pathogens are difficult to identify, which poses problems in antibiotic management. This article reviews the common as well as new, emerging pathogens, as well as the guidelines for management of pediatric CAP. Current guidelines for pediatric CAP continue to recommend the use of high-dose amoxicillin for bacterial CAP and azithromycin for suspected atypical CAP (usually caused by Mycoplasma pneumoniae) in children., (Copyright © 2013 Elsevier Inc. All rights reserved.)

A patient presented diffuse pulmonary parenchymal micronodules. Tropheryma whipplei was detected in the saliva, a bronchial biopsy and bronchoalveolar fluid. PAS staining, immunohistochemistry and PCR for T. whipplei were negative in the duodenal biopsies. T. whipplei was isolated from the bronchoalveolar fluid, reinforcing its role as a respiratory pathogen., (Copyright © 2011 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

Objectives: Early diagnosis of smear-negative tuberculosis remains challenging. The role of an interferon-gamma release assay (IGRA) in discriminating active pulmonary tuberculosis (PTB) among cases of 'pneumonia' was investigated., Methods: Consecutive patients admitted to an acute hospital in Hong Kong (intermediate TB burden) during 2006-2008 because of pneumonia and suspected PTB were recruited for IGRA (Quantiferon-TB Gold, QFN-G) study. Diagnosis of tuberculosis was confirmed by mycobacterial culture or histology., Results: Altogether 179 patients were recruited (median (IQR) age 59 (44-75), 68.7% male); active PTB was confirmed in 63 (35.2%). Among the AFB-smear-negative 'pneumonias' (n = 152), age>50 (OR 0.27, 95% CI 0.09-0.84), absence of weight loss (OR 0.30, 95% CI 0.10-0.88), and negative IGRA (OR 0.08, 95% CI 0.03-0.25) were independently associated with lower risks of PTB. The overall sensitivity, specificity, positive and negative predictive values for the IGRA in diagnosing active PTB were 60%, 87%, 72% and 80% respectively. Among smear-negative 'pneumonias' (n = 152), the performance values of IGRA were 64%, 87%, 62% and 88% respectively; in the absence of characteristic clinical or radiographic features of PTB, the negative predictive value (NPV) improved to 90-95%., Conclusions: The high NPV of QFN-G among smear-negative 'pneumonias' can be useful for risk stratification in hospitalized patients suspected of PTB. Further investigation on the role of these assays in patient management is warranted., (Copyright © 2011 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

Introduction: Sputum Gram stain and culture have been said to be unreliable indicators of the microbiological diagnosis of bacterial pneumonia. The etiological diagnosis of pneumonia is surrounded by great degree of uncertainty. This uncertainty should be and can be calculated and incorporated in the diagnosis and treatment., Study Objectives: To determine the diagnostic accuracy and diagnostic value of sputum Gram stain in etiological diagnosis and initial selection of antimicrobial therapy of bacterial community acquired pneumonia (CAP). DESIGN-METHOD: Prospective study of 1390 patients with CAP admitted January 2002-June 2008, to our institutions. Of the 1390 patients, 178 (12.8%) fulfilled the criteria for inclusion into this study (good-quality sputa and presence of the same microorganism in blood and sputum cultures which was used as gold standard for assessing the diagnostic accuracy and diagnostic value of sputum Gram stain)., Results: The sensitivity of sputum Gram stain was 0.82 for Pneumococcal pneumonia, 0.76 for Staphylococcal pneumonia, 0.79 for Haemophilus influenzae pneumonia and 0.78 for Gram-negative bacilli pneumonia. The specificity of sputum Gram stain was 0.93 for Pneumococcal pneumonia, 0.96 for Staphylococcal pneumonia, 0.96 for H. influenzae pneumonia and 0.95 for Gram-negative bacilli pneumonia. The positive likelihood ratio (LR+) was 11.58 for Pneumococcal pneumonia, 19.38 for Staphylococcal pneumonia, 16.84 for H. influenzae pneumonia, 14.26 for Gram-negative bacilli pneumonia. The negative likelihood ratio (LR-) was 0.20 for Pneumococcal pneumonia, 0.25 for Staphylococcal pneumonia, 0.22 for H. influenzae pneumonia, and 0.23 for Gram-negative bacilli pneumonia., Conclusions: Sputum Gram stain is a dependable diagnostic test for the early etiological diagnosis of bacterial CAP that helps in choosing orthological and appropriate initial antimicrobial therapy.

Hospital-acquired pneumonia (HAP) is one of the most common causes of nosocomial infection, morbidity, and mortality in hospitalized patients. Many patient- and disease-specific factors contribute to the pathophysiology of HAP, particularly in the surgical population. Risk-factor modification and inpatient prevention strategies can have a significant impact on the incidence of HAP. While the best diagnostic strategy remains a subject of some debate, prompt and appropriate antimicrobial therapy in patients suspected of having HAP has been shown to significantly decrease mortality. Because the pathogens responsible for HAP are frequently more virulent and have greater resistance to commonly used antimicrobials than other pathogens, clinicians must have knowledge of the resistance patterns at their institutions to choose appropriate therapy.

Bordetella holmesii is a rare cause of human infection, mainly in the immunocompromised host, and is associated with bacteremia, respiratory tract infection and endocarditis. Herein, we describe a patient with severe relapse of nephrotic syndrome associated with bacteremic B. holmesii pneumonia.

Pneumonia is one of the most common global childhood illnesses. The diagnosis relies on a combination of clinical judgement and radiological and laboratory investigations. Streptococcus pneumoniae remains the most important cause of childhood community-acquired pneumonia. In addition, viruses (including respiratory syncytial virus) and atypical bacteria (Mycoplasma and Chlamydia) are likely pathogens in younger and older children in developed countries. In the minority of cases only, the actual organism is isolated to guide treatment. Antibiotics effective against the expected bacterial pathogens should be instituted where necessary. The route and duration of antibiotic therapy, the role of emerging pathogens and the impact of pneumococcal resistance and conjugate pneumococcal vaccines are also discussed.

Methicillin-resistant Staphylococcus aureus (MRSA) is being recognized increasingly as a cause of community-acquired infection. The organism usually causes skin and soft tissue infection. Here, we present a patient with community-acquired MRSA pneumonia and review the literature. The patient, a 37-year-old Saudi male with no significant medical history was admitted with fever, respiratory distress and scrotal ulceration. Scrotal swabs and blood cultures grew MRSA. Imaging studies showed necrotizing pneumonia. Physical examination and echocardiographic findings revealed no evidence of endocarditis. The patient was treated successfully with 4 weeks of intravenous vancomycin. The infection appears to have originated in the skin and subcutaneous tissues of the scrotum, and subsequently led to necrotizing pneumonia. Community-acquired MRSA pneumonia has been associated with the production of Panton-Valentine leukocidin.

Purpose: To evaluate the variables associated with mortality of patients with community-acquired pneumonia who require mechanical ventilation and to determine the attributable morbidity and intensive care unit (ICU) mortality of community-acquired pneumonia., Material and Methods: Retrospective cohort study carried out in 361 ICUs from 20 countries including 124 patients who required mechanical ventilation on the first day of admission to the hospital due to acute respiratory failure secondary to severe community-acquired pneumonia. To assess the factors associated with outcome, a forward stepwise logistic regression analysis was performed, and to determine the attributable mortality of community-acquired pneumonia, a matched study design was used., Results: We found 3 independent variables significantly associated with death in patients with community-acquired pneumonia requiring mechanical ventilation: simplified acute physiological score greater than 45 (odds ratio, 5.5 [95% confidence interval, 1.7-12.3]), shock (odds ratio, 5.7 [95% confidence interval, 1.7-10.1]), and acute renal failure (odds ratio, 3.0 [95% confidence interval, 1.1-4.0]). There was no statistically significant difference in ICU mortality among patients with or without community-acquired pneumonia (32% vs 35%; P=.59)., Conclusions: Community-acquired pneumonia needing mechanical ventilation is not a disease associated with higher mortality. The main determinants of patient outcome were initial severity of illness and the development of shock and/or acute renal failure.

Fusobacterium species are anaerobic Gram-negative bacilli, which colonise the mucus membranes of man and animals and can cause a number of clinical manifestations including Lemierre's disease (postanginal septicaemia), abdominal infection and deep-seated abscesses. The incidence of fusobacterium infections appears to be increasing, and we present three cases of fusobacteriosis who presented with features of community acquired pneumonia (CAP). Cases were treated with benzyl penicillin and metronidazole, co-amoxiclav and metronidazole and amoxicillin and clarithromycin. Since some of the Fusobacterium species are resistant to penicillin and erythromycin, treatment with these antibiotics in cases of fusobacteriosis presenting as CAP may lead to treatment failure. A high index of clinical suspicion is required to recognise this rare cause of CAP.

The method to diagnose ventilator-associated pneumonia (VAP) ranges from physical examination to invasive procedures. In this section, the use of nonbronchoscopic techniques are reviewed. These include the traditional methods of reviewing the patient's clinical presentation and chest roentgenogram. Although these techniques are not specific, they are useful in helping the clinician in determining when to proceed with more tests to diagnose pneumonia. Methods for sampling lower respiratory tract secretions in an intubated patient include endotracheal aspirates as well as deeper samples obtained by protected brush or a nonbronchoscopic bronchoalveolar lavage catheter. Respiratory cultures can be useful in determining what is causing the pneumonia. However, the distinction between colonization and true infection is best understood if the samples are handled so that semiquantitative culture results can be reported. By using this approach, the physician should be able to better direct therapy and reduce mortality from pneumonia in the intensive care unit (ICU).

The spectrum of pulmonary manifestations in patients infected with human immunodeficiency virus (HIV) is broad, including many infectious and noninfectious complications. In the evaluation of an HIV-infected patient with diffuse pulmonary disease a definitive diagnosis is preferred over empiric therapy in most patients. Patients with focal consolidation usually receive empiric treatment for community-acquired pneumonia, with nonresponders undergoing additional diagnostic testing. Bronchoscopy remains a cornerstone in the diagnostic evaluation. A multilobar bronchoalveolar lavage (BAL) is usually sufficient for the diagnosis of Pneumocystis carinii pneumonia (PCP) and avoids the additional complications of hemorrhage and pneumothorax associated with transbronchial biopsy (TBBX). However, TBBX improves the sensitivity for diagnosis of tuberculosis and fungal pneumonias and is necessary to confirm invasive aspergillosis. Definitive criteria for diagnosis of cytomegalovirus pneumonitis have yet to be established, although bronchoscopic specimens usually are used. Tissue confirmation with TBBX is required for the diagnosis of noninfectious disorders such as non-Hodgkin's lymphoma and lymphocytic and nonspecific pneumonitis. Bronchoscopic visualization of typical lesions often is sufficient for the presumptive diagnosis of Kaposi's sarcoma (KS) although the diagnostic yield is enhanced by the detection of human herpes virus 8 in BAL samples.

The concepts of nonresolving and progressive pneumonia are difficult to define: both refer to a failure in the therapeutic response, which in the case of progressive pneumonia may cause a medical emergency even in the first 72 hours after empiric treatment. The incidence of nonresolving pneumonia in community-acquired pneumonia is approximately 10%, and greater than 30% in nosocomial pneumonia. Mortality in nonresponding pneumonia increases 3-fold in community-acquired and 5-fold in nosocomial pneumonia compared with global mortality in hospitalized patients. Factors associated with the resolution of pneumonia are related to the host, the microorganisms, and the cytokine response that modulates the relationship between them. Causes of nonresolving or progressive pneumonia may be infectious or noninfectious. Management of nonresponding patients requires a reevaluation of epidemiologic data, a complete microbiologic investigation, with conventional and invasive respiratory samples, and performance of a new radiographic study. Empiric therapeutic changes are aimed at broadening bacteriologic coverage to treat resistant or unusual microorganisms.

Bronchoscopy with bronchoalveolar lavage (BAL) is a frequently performed, minimally invasive endoscopic examination in patients with unclear infiltrates or pulmonary infections. It can be performed safely in patients with compromised immune systems of different etiologies. This article summarizes the experience with and efficacy of BAL in different disease states in this clinical circumstance. Because human immunodeficiency virus (HIV)-related diseases and acquired immune deficiency syndrome (AIDS) patients show different characteristics when compared with patients with other reasons for immunosuppression, they are discussed separately. Clinical algorithms are presented.

Pneumonia remains foremost a clinical diagnosis. However, symptoms of lower respiratory infection, including fever, cough, purulent sputum, dyspnea, and pleuritic pain as well as the clinical findings of tachypnea, tachycardia, hypoxemia, and auscultatory signs of consolidation, are not unique to pneumonia. Chest radiographs are therefore routinely required to confirm the clinical suspicion of pneumonia. This article discusses the limitations and pitfalls in the clinical and radiographic diagnosis of both community-acquired pneumonia and hospital-acquired, especially ventilator-associated, pneumonia. Given the difficulties of clinical diagnosis in pneumonia, empiric antibiotic treatment often is used. Inherent in the use of empiric therapy is the assumption that a favorable clinical response indicates both that pneumonia is present and that the empiric treatment is adequate. An accurate assessment of the normal, expected response of pneumonia to antibiotic therapy is therefore crucial. A discussion of the clinical response to treatment concludes the article.

Lower airway problems of the adult horse are commonly encountered by the practitioner. Particularly susceptible populations include horses transported for any significant distance and young horses grouped together for training and/or competition. This article presents some of the commonly encountered problems of this patient population, including bacterial pneumonia/pleuropneumonia and influenza, and some uncommon ones, including pulmonary edema, pneumothorax/hemothorax, and acuterespiratory distress syndrome. Information is presented that should allow the practitioner to diagnose these problems accurately and initiate rational treatment plans.

Rhodococcus equi is an animal pathogen that occasionally causes opportunistic infections in immunocompromised patients. The most common clinical picture is one of necrotizing pneumonia with a tendency toward cavitation and the formation of abscesses. We report a case of pneumonia caused by R equi in a renal transplant patient. An excellent response was shown to antibiotic treatment. Symptoms regressed, and the progressive disappearance of the lesion was confirmed on follow-up computed tomography scans. Surgical intervention or other invasive procedures were not required. To our knowledge, 14 cases of infection by R equi in solid-organ transplant patients have been described to date. Nine were recipients of a renal allograft. Surgery was required in many of these patients, and all the renal transplant recipients required the use of invasive therapeutic techniques, such as pleural drainage. This is the first case of a renal transplant recipient in whom radiologic presentation was as a solid nodule without ensuing cavitation that resolved exclusively with antibiotic treatment.

A 20-year-old young man suffered from severe protein-losing enteropathy 4 years after Fontan operation. His postoperative haemodynamics were unfavourable in terms of poor myocardial contractility and moderate atrioventricular prosthetic paravalvar leakage. A 2-week trial of steroid therapy for protein-losing enteropathy was given without success. The clinical course was complicated by Legionella pneumophila pneumonia and bacteraemia, which respond to the combination therapy with intravenous erythromycin and ciprofloxacin. The vulnerability of the patient to infection was related to an immuno-deficiency state secondary to protein-losing enteropathy and steroid therapy. Steroids should be used with caution in the management of protein-losing enteropathy after Fontan operation., (Copyright 2001 The British Infection Society.)

We describe three patients with invasive group A streptococcal infection, admitted during the 3 months between November 1996 and February 1997. All patients were previously healthy Japanese women who developed a profound shock, with a rapidly fatal outcome, after experiencing flu-like symptoms. All cases conformed to the case definition of toxic shock-like syndrome (TSLS).Currently, the pathogenic mechanism of TSLS remains unclear. Known microbial virulence factors can not sufficiently explain the occurrence of TSLS, and it has been generally considered that host factors may be contributory. On pathological examination, each patient had one organ or tissue that was most severely involved: Case 1 a non-penetrating trauma; Case 2 a pregnant uterus; and Case 3 a pulmonary lesion reminiscent of lymphocytic interstitial pneumonia. On the basis of clinicopathological features of these cases, we propose that the coexistence of 'enhancing tissue focus' may be one of host factors for the progression of TSLS in patients infected with non-invasive GAS., (Copyright 2001 The British Infection Society.)

Ventilator-associated pneumonia (VAP) is considered the most frequent infection in the intensive care unit (ICU), although incidence rates depend on the diagnostic methods. Because VAP has been associated with increased mortality and greater costs for medical care, prevention remains an important goal for intensive care medicine. Selective digestive decontamination (SDD), the most frequently studied method of infection prevention, is still controversial despite more than 30 prospective randomized trials and 6 metaanalyses. SDD reduces the incidence of VAP diagnoses, but beneficial effects on duration of ventilation or ICU stay, antibiotic use, and patient survival have not been shown unequivocally. Although recent metaanalyses suggest a 20% to 40% decrease in ICU mortality for SDD used with systemic prophylaxis, this benefit should be confirmed in a large, prospective, randomized study, preferably with a cost-benefit analysis. Selection of pathogens resistant to the antibiotics used in SDD remains the most important drawback of SDD, rendering SDD contraindicated in wards with endemic resistant problems. Other methods of infection prevention that do not create a selective growth advantage for resistant microorganisms may be more useful. Among these are the use of endotracheal tubes with the possibility of continuous aspiration of subglottic secretions, oropharyngeal decontamination with antiseptics, or the semirecumbent treatment position of patients. Although these methods were successful in single studies, more data are needed. Notwithstanding the potential benefits of these interventions, such classic infection control measures as handwashing remain the cornerstone of infection prevention.

Hospital-acquired pneumonia (HAP) remains a significant cause of morbidity and attributable mortality, especially among patients undergoing mechanical ventilation. The clinical approach to this disorder continues to evolve. Although our understanding of the epidemiology, risk factors, and pathogenesis of this disorder are expanding, consensus on diagnostic, therapeutic, and preventive strategies is lacking. Although outcome is significantly improved by the rapid introduction of appropriate antimicrobial therapy, presently available diagnostic tests rarely are able to identify a specific pathogen when antimicrobial choices are made. Thus, most therapy is by necessity empirical. The American Thoracic Society (ATS) published guidelines for the empiric treatment of HAP in 1996, this article reviews the recommendations of these guidelines and, if new information is available, updates these recommendations.

Community-acquired bacterial pneumonias are among the most common of infectious diseases. The diagnosis of the etiological agent is becoming more challenging and more critical as new organisms are recognized as pathogens, and as well established agents become increasingly resistant to antimicrobial agents. The value of clinical microbiology laboratory data in the management of pneumonia is controversial. A well recognized, published guideline suggests that no laboratory studies be performed. Yet common practice and a more recent guideline advocate routine collection of sputum for Gram's stain and culture, along with traditional blood work. Given the increasing need to distinguish among a long list of possible pathogens and the need to recognize antibiotic resistance, it seems most prudent to include microbiological studies. This information can be used to guide initial therapy, and perhaps limit the overutilization of broad-spectrum antimicrobials. However, a prerequisite for the use of all cunently available test methods is their deployment in patients for whom there is clinical and radiographic evidence of pneumonia because recovery of a microorganism, especially from sputum, will occur with or without this clinical condition.

The second most common nosocomial infection in the United States is pneumonia, with the highest rates seen in patients requiring mechanical ventilation. Nosocomial pneumonia is a serious disease associated with significant morbidity and mortality; crude mortality rates have been estimated at 20% to 50%. The rapid institution of appropriate antimicrobial therapy has been shown to improve mortality in patients with ventilator associated nosocomial pneumonia. Thus, the identification of nosocomial pneumonia with a timely microbiologic diagnosis is important for the management of these patients. However, the accurate diagnosis of nosocomial pneumonia, along with identification of the responsible organism(s), can be challenging. This task becomes even more difficult in patients who are mechanically ventilated. The presence of new pulmonary infiltrates along with clinical criteria including fever, cough, and purulent secretions are neither sensitive nor specific for the diagnosis of nosocomial pneumonia. The laboratory can enhance the accuracy of pneumonia diagnosis, as well as provide the identification of an etiologic organism(s). There are, however, many challenges which confront the laboratory including: the ability to identify organisms from an extensive microbiologic spectrum; distinguishing colonization from infection of predominately gram-negative oropharyngeal flora; and providing timely results. This article reviews the various diagnostic tests available for nosocomial lung infections, and in particular, ventilator associated pneumonia including: blood cultures; pleural fluid; expectorated sputum; endotracheal aspirates; and respiratory specimens obtained by more invasive techniques using bronchoscopy and transthoracic needle aspiration. Emphasis is placed on optimal specimen collection, the processing of samples in the laboratory, and on the evaluation of potential risks and benefits associated with the varying techniques.

"Atypical pneumonia" is a term loosely applied to lower respiratory tract infections that are not characterized by signs and symptoms of lobar consolidation. This description can apply to disease caused by a variety of bacterial, viral and even protozoan organisms. In reality, differentiation as to etiology of pneumonia cannot be distinguished on the basis of clinical presentation. This review will discuss the epidemiology, clinical manifestations, and laboratory diagnosis of Mycoplasma pneumoniae, Chlamydia sp., Legionella sp., Bordetella pertussis, and Coxiella bumetii, the most common agents associated with atypical pneumonia. Unfortunately, because many of these pathogens are intracellular, culture systems are either not available or the techniques employed are costly, time-consuming or unsafe. Until molecular techniques are standardized and widely available, diagnosis will depend upon serologic confirmation. Given the relative importance of these organisms as causes of community acquired pneumonia, current practice guidelines recommend empiric therapy with a macrolide in patients well enough to be treated as an outpatient. However, diagnostic tests should be performed in any patient requiring hospitalization.

Nosocomial infection in the critically ill results from defects in the intrinsic barriers to microbial invasion. The diagnosis is complicated by an inability to perform an adequate physical examination in a patient with several compounding findings, usually necessitating sophisticated technologies to aid in the diagnosis. Pneumonia, line sepsis, urosepsis, sinusitis, endocarditis, peritonitis, and acalculous cholecystitis are the more common infections that challenge the care of the critically ill. Antibiotic therapy is adjunctive to efforts to preserve the barrier, but should be started early, should be targeted as specifically as possible to the offending organisms, and should be dosed adequately to ensure an effective concentration in the infected tissue.

Anaerobic organisms play a major role in pleuropulmonary infections. Clinical manifestations range from simple aspiration to acute, severe, necrotizing pneumonias to chronic infections, such as lung abscess and empyema. Implicated pathogens are usually of endogenous origin. Laboratory diagnosis of anaerobic pleuropulmonary infections is based on recovering the etiological agent from clinical specimens. Appropriate specimens include pleuml fluid, transtracheal aspirates, transthoracic aspirates and fiberoptic bronchoscopic aspirates. Collection and transport of uncontaminated specimens is crucial to the recovery of the causative agents. Evaluation of a Gram's stain of clinical material provides a guide to initial therapy. Pigmented and non-pigmented Prevotella species, Fusobacterium nucleatum, Peptostreptococcus species, and Bacteriodes species are the most commonly recovered anaerobes in pleuropulmonary infections. Successful treatment of anaerobic pleuropulmonary infections requires a combination of antibiotic therapy and surgical interventions. Routine susceptibility testing of recovered isolates is rarely warranted.

The treatment of bacterial pneumonia can occur either in the community or hospital setting depending on the clinical status of the child. In the community, supportive management includes anti-pyretics, analgesia and early review by a medical practitioner if there is deterioration or no response to oral antibiotics within 48 hours. Suitable first-line antibiotics in the under fives are penicillin- or cephalosporin-based and in the over fives macrolides may also be considered. In a severely ill child, good oxygenation is essential and oxygen may be delivered by mask, nasal prong or headbox. Persistent fever, despite appropriate treatment warrants further investigations. The most common complication is an empyema and treatment is effective drainage with continuing high-dose antibiotics. Other lung complications include abscess formation and pneumatoceles. The syndrome of inappropriate anti-diuretic hormone secretion occurs in approximately one third of hospitalized patients with pneumonia. A rare but important complication is pericarditis.

This overview has been supported by a review of the literature referring to the management of community-acquired pneumonia (in preparation). Difficulties diagnosing bacterial pneumonia include identifying the pathogens and the validation of radiographic signs suggesting bacterial or mycoplasmal infection. The World Health Organisation (WHO) has published guidelines for diagnosis which seem to be as relevant for developed as developing countries. The main diagnostic features are tachypnoea, fever greater than 38.5 degrees C and chest recession without wheeze. Radiographic features lag behind clinical findings and provide little additional help when antibiotic treatment is considered but are crucial in the proper management of complications.

Bacterial pneumonia is significantly more common in persons who are HIV-infected than in the general population and is most common among injection drug users and in persons with advanced HIV disease and immunosuppression. The clinical features of bacterial pneumonia are similar to those in HIV-seronegative persons, but bacteremia is more common. When a pathogen is identified, Streptococcus pneumoniae is consistently the most common, occurring in 20% to 70% of cases. Haemophilus influenzae, Staphylococcus aureus, Escherichia coli, and other gram-negative organisms are mainly responsible for the remainder of bacterial pneumonia episodes in the United States, Central Africa, Australia, and England. In some studies, Chlamydia pneumoniae was recognized as a common cause in persons with early HIV disease, whereas Pseudomonas aeruginosa is recognized as a community- and hospital-acquired lower respiratory tract pathogen in patients with severe immunosuppression. Although antimicrobial therapy is frequently empiric, it should be tailored to the severity of illness, local prevalence of infections, resistance patterns, or when an etiologic agent is identified. The treatment response is similar in patients with and without HIV infection, but bacterial pneumonia may accelerate the progression of HIV disease. Preventative measures include use of the polyvalent pneumococcal vaccine, especially early in the course of HIV infection, when it is most likely to be effective. The incidence of bacterial pneumonia is also reduced in HIV-seropositive persons who use trimethoprim-sulfamethoxazole to prevent Pneumocystis carinii pneumonia.

The initial in-hospital management of adult patients with community-acquired pneumonia can be divided into five major steps: an early recognition of the patient with presumptive pneumonia, assessment of the severity of illness, establishment of an etiologic diagnosis, supportive therapy, and decision regarding initiation of empirical therapy. In most European recommendations, the empirical antibiotic treatment is directed against "the most likely pathogen," based on epidemiological, clinical, and laboratory data, and on the severity of illness. In contrast, newer North American guidelines have focused on the severity of illness of community-acquired pneumonia. As a consequence, the use of a broader initial antibiotic coverage, including extended-spectrum cephalosporins and combinations, seems to be more common in North America than in Europe.

Community-acquired pneumonia (CAP) is common. There is no entirely satisfactory way of defining pneumonia using clinical criteria alone. New focal chest signs on examination in the presence of a systemic illness that is suggestive of a lower respiratory tract infection seems to be the best clinical finding that indicates pneumonia. Progress has been made in identifying simple clinical features that relate to prognosis and allow the general practitioner to decide whether care in the community is appropriate or hospital referral is required. Psychosocial factors for the patient will also remain important. Most patients who have CAP that is mild enough to be managed in the community will require few, if any, investigations. A chest radiograph is appropriate in all patients to exclude an underlying lung tumor. Measurement of surrogate markers of acute infection, such as C-reactive protein, may prove useful to the general practitioner if near testing were to become feasible. The antibiotic management for CAP for patients well enough to be managed at home can be simple and logical, providing general practitioners have some knowledge regarding likely pathogens and etiologic and epidemiological clues. Any antibiotic chosen must suppress Streptococcus pneumoniae, which remains the most common cause of CAP.

Causative diagnosis of pneumonia is problematic. The lack of a reliable gold standard for diagnosis has also made the development of new diagnostic methods for different microbes causing pneumonia difficult. Serologic methods are continuously used in the diagnosis of pneumonia caused by viruses and atypical bacteria. However, rapid diagnostic methods are urgently needed to guide clinicians to choose proper antibiotic treatment because resistant bacteria are emerging in different parts of the world.

Community-acquired pneumonia (CAP) is the most common serious infection encountered in medical practice, with 1% to 10% of patients requiring admission to a hospital. The mortality rate of patients admitted is considerable, ranging from 5% to 25%. Motivated by the results of the British Thoracic Society (BTS) study, different investigators have identified several risk factors associated with a high mortality rate. The assessment of the severity of CAP can be determined at three stages: (1) At home or during the general practitioner's (GP) consultation; (2) In the hospital outpatient clinic or emergency room; and (3) In the medical ward and/or intensive care unit (ICU). At stage 1, medical history, symptoms, and signs (respiratory rate!) seem to be relevant. However, it is not easy for GPs to diagnose pneumonia with any degree of certainty because of the limited diagnostic tools available. Once a patient is referred to a hospital (stage 2), factors such as clinical presentation, comorbidities, and laboratory and radiographic factors must be determined to identify those patients who are at risk. BTS criteria (respiratory rate > or =30/min, diastolic blood pressure < or = 60 mm Hg, blood urea nitrogen >7 mmol/L), but also other combinations of criteria, are associated with a multiple-fold increased risk of death. However, most of these prognostic models have low positive predictive value, suggesting that the risk of death is overestimated when these models are implemented in daily practice. In general, younger patients without comorbidities can be treated in an outpatient setting; sometimes brief inpatient observation is necessary. Elderly patients, especially those with comorbidities and severe illness need inpatient care, sometimes resulting in treatment from an ICU. Severe CAP (stage 3) is defined as pneumonia associated with respiratory failure and/or hemodynamic instability requiring treatment in an ICU, and has a death rate varying from 21% to 54%. Pneumonia- and non-pneumonia-related complications are often observed. Adverse prognostic factors that have been reported in several studies are: advanced age, the presence of comorbidities, development of septic shock, need for mechanical ventilation (including use of positive end-expiratory pressure and FiO2 >60%), development of adult respiratory distress syndrome, progression of radiographic abnormalities, bacteremia (especially when due to P aeruginosa), non-pneumonia-related complications, and inadequate antibiotic treatment. To reduce mortality, prospective studies focusing on adverse prognostic factors at the start of and during antibiotic treatment are urgently needed at all three stages.

The incidence of community-acquired pneumonia (CAP) in the elderly is higher compared to younger populations. In addition, pneumonia in the elderly is a life-threatening problem. As our demographics have changed, clinicians have developed a heightened interest in managing pneumonia in the elderly. The development of pneumonia in elderly patients differs from that in younger individuals due to a complex array of factors. (1) The organisms involved depend on the setting in which the pneumonia developed: either the nonhospitalized elderly patient with CAP or the institutionalized patient who develops nursing-home-acquired pneumonia. (2) Underlying comorbid conditions commonly exist in the elderly that affect the etiology and outcome of pneumonia. Overall, Streptococcus pneumoniae and Haemophilus influenzae are still the most common etiologies of pneumonia in the elderly. The true role of gram-negative bacilli remains unclear although these micro-organisms may be more common etiologic agents in nursing-home pneumonia. Some recent studies from Mediterranean areas have reported high rates of infection by Chlamydia pneumoniae, but the real role of this micro-organism has to be confirmed. Another important issue is that the presenting symptoms of pneumonia in the elderly can be subtle and sometimes difficult to recognize. Fever is frequently absent, and delirium or alteration of functional physical capacity may be the only manifestations. Mortality in the elderly with CAP is higher when compared to younger populations. However, this may be explained by the concomitant presence of comorbid conditions more than by age per se. This statement has to be kept in mind when considering hospital and, particularly, intensive care unit admissions. Finally, antibiotic pharmacokinetics in the elderly populations with CAP ought to be considered to avoid frequent side-effects and complications. Overall, antibiotic regimens in hospitalized elderly patients with CAP do not differ from other hospitalized CAP populations. An organized approach to assessing elderly patients with suspicion of pneumonia and an awareness of common pitfalls in the management of this pulmonary infection in this population are essential to improving outcomes.

Much of what we know about childhood community-acquired pneumonia in developed countries comes from studies in Europe, where approximately 2.5 million cases of childhood pneumonia occur yearly. Streptococcus pneumoniae, Mycoplasma pneumoniae, and respiratory syncytial virus are the most common causative agents. Blood culture is seldom positive and mortality is very low in developed countries. Tachypnea and crackles on auscultation are the major findings suggesting pneumonia, but their sensitivity and specificity are not high enough, and, if possible, a radiograph of the chest should be obtained to confirm the diagnosis. Recommendations for antibiotic treatment vary. Based on the etiologic studies we suggest macrolides as the first choice in outpatients and depending on the clinical picture and severity of the illness penicillin G, macrolide, or cefuroxime plus macrolide in hospitalized patients. The recovery of children with pneumonia is usually rapid and in uncomplicated cases routine follow-up radiographs and check-ups are unnecessary.

Purpose: Mini-bronchoalveolar lavage (m-BAL) and blind-protected brush sampling (b-PSB) are minimally invasive methods of diagnosing pneumonia in mechanically ventilated patients. The aim of this study was to compare these techniques in a prospective study at a medical and surgical intensive care unit in a university-affiliated community teaching hospital., Patients and Methods: One hundred and ninety episodes of pneumonia was suspected in 175 mechanically ventilated patients. Sequential b-PSB followed by m-BAL were performed by respiratory therapists who had undergone specialized training. A b-PSB quantitative culture greater than 1,000 cfu/mL and a m-BAL greater than 10(4) cfu/mL was considered diagnostic of pneumonia. Colony counts between 500 and 1,000 cfu/mL and 5,000 - 10(4) cfu/mL, respectively, were considered borderline positive., Results: One hundred and ninety paired specimens were obtained from 175 patients. The diagnostic agreement between the two techniques was 90%. Sixty-six patients (37%) were considered to have bacterial pneumonia. In 108 episodes, patients were receiving concurrent antibiotics; pneumonia was diagnosed in 30 (27%) of these cases compared with 36 of 82 (43%) episodes off antibiotics (P = .03). In 6 episodes, m-BAL was negative and b-PSB was positive (1 patient receiving antibiotics). In 13 episodes, b-PSB was negative and m-BAL was positive (7 patients were receiving antibiotics). The b-PSB took 30 +/- 8 seconds to perform and was complicated by minor bleeding in 3 cases. The m-BAL took 5 +/- 2 minutes to perform, was considered easy in 105 cases, difficult/very difficult in 63, and failed in 2 patients. Significant coughing occurred in 98 patients with other minor reversible complications occurring in a further 20 cases., Conclusions: In mechanically ventilated patients with suspected pneumonia both b-PSB and m-BAL can be performed safely by respiratory therapists. The tests complement each other and likely reduce the number of false-negative results.

Community-acquired pneumonia (CAP) remains a major cause of morbidity and mortality in the United States. The ideal of a simple diagnostic evaluation yielding a specific etiologic diagnosis allowing directed antimicrobial therapy remains elusive. Empiric therapy is justified as initial management, as the specific bacteriological etiology of most cases of CAP is usually unknown, and delaying therapy while attempting to find a diagnosis may be injurious to the patient. Guidelines have been developed to assist in the recognition and evaluation of CAP based on age and underlying medical illness as predictors of outcome. While these criteria are by no means perfect and cannot be applied to every individual, they offer a rational approach to the initial management of the patient.

Antibiotic treatment for community-acquired pneumonia (CAP) can be specifically directed at an identified etiologic agent, or empirically formulated based on consideration of the likely pathogens according to the patient's age, underlying diseases, and clinical presentation. In recent years the empirical approach has become increasingly popular, and there is a growing trend away from efforts to make a microbiological diagnosis. This article reviews the tests that are currently available for the diagnosis of CAP, including stains, cultures, antigen-detection techniques, nucleic acid amplification, and serologies. Arguments then are presented in support of efforts to make a microbiological diagnosis. Clinical and radiographic features of CAP are not sufficiently distinctive to infer a specific microbial cause. Identification of the etiologic agent can be made in the majority of cases, and most microbiological diagnoses can be made rapidly with simple tests. The best opportunity to make an etiologic diagnosis is before antibiotics are administered. Identification of the microbial cause of pneumonia permits specific, narrow-spectrum antibiotic treatment that may be more effective, less toxic, and less expensive than empiric therapy. Microbiological data from individual patients contributes to understanding the local microbial epidemiology of CAP, including the local distribution of pathogens and their antimicrobial resistance patterns, information that is invaluable in the construction and modification of empiric treatment regimens. The reliance on empiric treatment engenders a false complacency, based on the erroneous assumption that broad-spectrum antibiotics will treat all cases of CAP. The unnecessary use of broad-spectrum antibiotic combinations in the empiric treatment of CAP contributes to the growing problem of antimicrobial resistance.