Quantitative culture of bronchoalveolar lavage fluid in community-acquired lower respiratory tract infections

Association between quantitative bacterial culture of bronchoalveolar lavage fluid and antibiotic requirement in dogs with lower respiratory tract signs

BACKGROUND

Historically, positive bacterial cultures from the lower respiratory tract (LRT) have been considered clinically relevant when quantitative bacterial cultures of bronchoalveolar lavage fluid (BALF) were >1700 colony forming units (cfu)/mL. However, this threshold might not accurately predict a requirement for antibiotics.

OBJECTIVES

To study whether quantitative BALF bacterial culture results were predictive of antibiotic requirement in dogs with LRT signs.

ANIMALS

Thirty-three client-owned dogs.

METHODS

Cross-sectional study. Dogs with positive quantitative bacterial culture of BALF were included. Dogs were divided into 2 groups, depending on whether they had a LRT infection requiring antibiotics (LRTI-RA) or LRT disease not requiring antibiotics (LRTD-NRA), based on thoracic imaging features, presence of intracellular bacteria on BALF cytology, and response to treatment. Predictive effect of cfu/mL and BALF total nucleated cell count (TNCC) on antibiotic requirement, adjusting for ongoing or prior antibiotic therapy and age, were studied using logistic regression.

RESULTS

Twenty-two and 11 dogs were included in the LRTI-RA and LRTD-NRA groups, respectively. The cfu/mL was not significantly predictive of antibiotic requirement, independent of ongoing or prior antibiotic treatment and age (LRTI-RA: median, 10 000 cfu/mL; range, 10-3 × 108 ; LRTD-NRA: median, 10  000 cfu/mL; range, 250-1.3 × 109 ; P = .27). The TNCC was not significantly predictive of antibiotic requirement when only dogs with bronchial disease were considered (LRTI-RA: median, 470 cells/μL; range, 240-2260; LRTD-NRA: median, 455 cells/μL; range, 80-4990; P = .57).

CONCLUSION AND CLINICAL IMPORTANCE

The cfu/mL is an inappropriate measure for determining whether antibiotics are of benefit in dogs with LRT signs.

A LAMP-based system for rapid detection of eight common pathogens causing lower respiratory tract infections

Lower respiratory tract infections (LRTIs) are a leading cause of morbidity and mortality worldwide and lack a rapid diagnostic method. To improve the diagnosis of LRTIs, we established an available loop-mediated isothermal amplification (LAMP) assay for the detection of eight common lower respiratory pathogens, including Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Escherichia coli, Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. The whole process can be achieved within 1 h (sample to results read out). We established an extraction free isothermal system. 528 sputum samples collected from patients suspected to have LRTIs were analyzed by the system (8 tests in each sample, a total of 4224 tests) and compared with the standard culture method (SCM). The samples with inconsistent results were further verified by Sanger sequencing and High-throughput sequencing (NGS). The detection limits of the LAMP assay for the 8 pathogens ranged from 10³ to 10⁴ CFU/mL. Upon testing 528 samples, the Kappa coefficients of all pathogens ranged between 0.5 and 0.7 indicated a moderate agreement between the LAMP assay and the SCM. All inconsistent samples were further verified by Sanger sequencing, we found that the developed LAMP assay had a higher consistency level with Sanger sequencing than the SCM for all pathogens. Additionally, when the NGS was set to a diagnostic gold standard, the specificity and sensitivity of the LAMP assay for LRTIs were 94.49% and 75.00%. The present study demonstrated that the developed LAMP has high consistency with the sequencing methods. Meanwhile, the LAMP assay has a higher detection rate compared to the SCM. It may be a powerful tool for rapid and reliable clinical diagnosis of LRTIs in primary hospitals.

Factors associated with coinfections in invasive aspergillosis: a retrospective cohort study

OBJECTIVES

To describe the coinfections in invasive aspergillosis (IA), to identify factors associated with coinfections, and to evaluate the impact of coinfection on mortality.

PATIENTS AND METHODS

We conducted a monocentric retrospective study of consecutive putative, probable, or proven IA that occurred between 1997 and 2017. All coinfections, with an onset within 7 days before or after the first sign of aspergillosis, were identified. Factors associated with coinfections and mortality were analysed by multivariable analysis.

RESULTS

Among the 690 patients with IA included in the study, the median age was 57 years (range 7 days to 90 years). A coinfection was diagnosed in 272/690 patients (39.4%, 95%CI 35.8-43.2). The location of this coinfection was pulmonary only in 131/272 patients (48%), bloodstream only in 66/272 patients (24%) and other/multiple sites in 75/272 patients (28%). Coinfections were bacterial (110/272 patients, 40%), viral (58/272, 21%), fungal (57/272, 21%), parasitic (5/272, 2%) or due to multiple types of pathogens (42/272, 15%). Factors associated with a coinfection in adjusted analysis were: allogeneic haematopoietic stem-cell transplantation (OR 2.3 (1.2-4.4)), other haematological malignancies (OR 2.1 (1.2-3.8)), other underlying diseases (OR 4.3 (1.4-13.6)), lymphopenia (OR 1.7 (1.1-2.5)), C-reactive protein >180 mg/L (OR 1.9 (1.2-3.0)), fever (OR 2.4 (1.5-4.1)), tracheal intubation (OR 2.6 (1.5-4.7)), isolation of two or more different Aspergillus species (OR 2.7 (1.1-6.3)), and the presence of non-nodular lesions on chest computed tomography (OR 2.2 (1.3-3.7) and OR 2.2 (1.2-4.0)). Coinfections were independently associated with a higher mortality at week 12 (adjusted HR 1.5 (1.1-1.9), p < 0.01).

CONCLUSIONS

Coinfections are frequent in IA patients and are associated with higher mortality.

The Detection of Bile Acids in the Lungs of Paediatric Cystic Fibrosis Patients Is Associated with Altered Inflammatory Patterns

Background: Cystic fibrosis (CF) is a hereditary disorder in which persistent unresolved inflammation and recurrent airway infections play major roles in the initiation and progression of the disease. Little is known about triggering factors modulating the transition to chronic microbial infection and inflammation particularly in young children. Cystic fibrosis respiratory disease starts early in life, with the detection of inflammatory markers and infection evident even before respiratory symptoms arise. Thus, identifying factors that dysregulate immune responsiveness at the earliest stages of the disease will provide novel targets for early therapeutic intervention. Methods: We evaluated the clinical significance of bile acid detection in the bronchoalveolar lavage fluid of clinically stable preschool-aged children diagnosed with CF. Results: We applied an unbiased classification strategy to categorize these specimens based on bile acid profiles. We provide clear associations linking the presence of bile acids in the lungs with alterations in the expression of inflammatory markers. Using multiple regression analysis, we also demonstrate that clustering based on bile acid profiles is a meaningful predictor of the progression of structural lung disease. Conclusions: Altogether, our work has identified a clinically relevant host-derived factor that may participate in shaping early events in the aetiology of CF respiratory disease.

Comparison of bronchoalveolar lavage fluid bacteriology and cytology in calves classified based on combined clinical scoring and lung ultrasonography

Respiratory tract infections are the leading cause of antimicrobial use in calves. Combining clinical examination and lung ultrasonography allows on-farm classification of calves as healthy or suffering from an upper respiratory tract infection (URTI), subclinical or clinical pneumonia. This might help to improve targeted antimicrobial therapy, restricting treatment to pneumonic cases. However, to what extent these diagnostic categories coincide with expected bacteriological and cytological bronchoalveolar lavage fluid (BALf) characteristics is currently unknown. The objective of this study was therefore to compare BALf bacteriology and cytology between healthy calves and calves with URTI, subclinical and clinical pneumonia. The hypothesis was that calves with subclinical and clinical pneumonia would have higher quantitative bacterial counts, bacterial isolation rates and neutrophil counts than URTIs or healthy animals. A cross-sectional study was performed on 305 indoor group-housed dairy and beef calves, from 62 farms. Calves were classified by combining clinical examination and lung ultrasonography. Clinical respiratory disease was defined using the Wisconsin score card and the Healthy Criterion (HC). The HC classified calves as clinically ill if at least one clinical sign was present. Ultrasonographic lung consolidation with a depth of ≥1 cm was considered indicative for pneumonia. Cytology and bacteriology were performed on BALf sampled by non-endoscopic bronchoalveolar lavage. Calves with clinical pneumonia were further subdivided based on culture result and presence of neutrophils phagocytosing bacteria. Combined lung ultrasonography and clinical examination (HC) classified 25.9 % (79/305) of the calves as healthy, 33.1 % (101/305) as URTI, 10.2 % (31/305) as subclinical and 30.8 % (94/305) as clinical pneumonia. Bacterial isolation rates and quantitative BALf culture results did not differ between groups. Calves with clinical pneumonia and neutrophil phagocytosis showed a significantly higher BALf neutrophil percentage compared to healthy calves (59.0 % vs. 37.7 % in healthy calves, P =.03). Inversely, lymphocyte percentage was lower in these calves (1.8 % vs. 5.3 % in healthy calves, P = .003). Classification of calves using lung ultrasonography and clinical scoring did not correspond with BALf bacteriology and cytology findings, as extrapolated from human and companion animal medicine. Under the current housing conditions of this study high rates of non-infectious airway inflammation or airway colonization by opportunistic pathogens, rather than infection might explain this. Isolation of respiratory pathogens from calves with various signs of respiratory disease or ultrasonographic lesions should be interpreted carefully. Of all cytological features, phagocytosis by neutrophils in BALf might be a useful criterion supporting the diagnosis of bacterial respiratory tract infection.

Rapid identification of respiratory bacterial pathogens from bronchoalveolar lavage fluid in cattle by MALDI-TOF MS

Respiratory tract infections are a major health problem and indication for antimicrobial use in cattle and in humans. Currently, most antimicrobial treatments are initiated without microbiological results, holding the risk of inappropriate first intention treatment. The main reason for this empirical treatment is the long turnaround time between sampling and availability of identification and susceptibility results. Therefore the objective of the present study was to develop a rapid identification procedure for pathogenic respiratory bacteria in bronchoalveolar lavage fluid (BALf) samples from cattle by MALDI-TOF MS, omitting the cultivation step on agar plates to reduce the turnaround time between sampling and identification of pathogens. The effects of two different liquid growth media and various concentrations of bacitracin were determined to allow optimal growth of Pasteurellaceae and minimise contamination. The best procedure was validated on 100 clinical BALf samples from cattle with conventional bacterial culture as reference test. A correct identification was obtained in 73% of the samples, with 59.1% sensitivity (Se) (47.2–71.0%) and 100% specificity (Sp) (100–100%) after only 6 hours of incubation. For pure and dominant culture samples, the procedure was able to correctly identify 79.2% of the pathogens, with a sensitivity (Se) of 60.5% (45.0–76.1%) and specificity (Sp) of 100% (100–100%). In mixed culture samples, containing ≥2 clinically relevant pathogens, one pathogen could be correctly identified in 57% of the samples with 57.1% Se (38.8–75.5%) and 100% Sp (100–100%). In conclusion, MALDI-TOF MS is a promising tool for rapid pathogen identification in BALf. This new technique drastically reduces turnaround time and may be a valuable decision support tool to rationalize antimicrobial use.

[Lung abscess: Diagnosis and management]

Lung abscesses are necrotic cavitary lesions of the lung parenchyma. They are usually caused by anaerobic bacteria or mixed flora and typically occur after aspiration. Primary lung abscesses occur in previously healthy patients with no underlying medical disorders and are usually solitary. Secondary lung abscesses occur in patients with underlying or predisposing conditions and may be multiple. The initial diagnosis is usually made by chest radiography showing a lung cavity with an air-fluid level. Typically, the cavity wall is thick and irregular, and a surrounding pulmonary infiltrate is often present. The differential diagnosis of pulmonary cavitation is wide, including different types of possible infections, neoplasia and malformations of the bronchial tree. Management is usually based on prolonged antibiotic treatment. Failure of conservative management, manifested by the persistence of sepsis and/or other abscess complications, may necessitate drainage with invasive techniques (percutaneous, endoscopic or surgical) or open surgical removal of the lung lesion in patients with good performance status and sufficient respiratory reserve.

Defining lower airway bacterial infection in children with chronic endobronchial disorders

BACKGROUND

Differentiating lower airway bacterial infection from possible upper airway contamination in children with endobronchial disorders undergoing bronchoalveolar lavage (BAL) is important for guiding management. A diagnostic bacterial load threshold based on inflammatory markers has been determined to differentiate infection from upper airway contamination in infants with cystic fibrosis, but not for children with protracted bacterial bronchitis (PBB), chronic suppurative lung disease (CSLD), or bronchiectasis.

METHODS

BAL samples from children undergoing bronchoscopy underwent quantitative bacterial culture, cytologic examination, and respiratory virus testing; a subset also had interleukin-8 examined. Geometric means (GMs) of total cell counts (TCCs) and neutrophil counts were plotted by respiratory pathogen bacterial load. Logistic regression determined associations between age, sex, Indigenous status, antibiotic exposure, virus detection and bacterial load, and elevated TCCs (>400 × 10³ cells/mL) and airway neutrophilia (neutrophils >15% BAL leukocytes).

RESULTS

From 2007 to 2016, 655 children with PBB, CSLD, or bronchiectasis were enrolled. In univariate analyses, Indigenous status and bacterial load ≥10⁵ colony-forming units (CFU)/mL were positively associated with high TCCs. Viruses and bacterial load ≥10⁴ CFU/mL were positively associated with neutrophilia; negative associations were seen for Indigenous status and macrolides. In children who had not received macrolide antibiotics, bacterial load was positively associated in multivariable analyses with high TCCs at ≥10⁴ CFU/mL and with neutrophilia at ≥10⁵ CFU/mL; GMs of TCCs and neutrophil counts were significantly elevated at 10⁴ and 10⁵ CFU/mL compared to negative cultures.

CONCLUSIONS

Our findings support a BAL threshold ≥10⁴ CFU/mL to define lower airway infection in children with chronic endobronchial disorders.

Shifted focus of bronchoalveolar lavage in patients with suspected thoracic malignancy: an analysis of 224 patients

BACKGROUND

Bronchoscopies are extensively adopted for diagnosing and staging thoracic malignancies, but studies are missing as how to keep the process streamlined and more efficient. To evaluate current role of bronchoalveolar lavage (BAL) for cancer and possible infection diagnosis when practicing comprehensive bronchoscopy for patients suspected with thoracic malignancy, and provide foundation for possible practice modification.

METHODS

We retrospectively analyzed a prospectively kept database of immunocompetent patients undergoing bronchoscopy for suspected non-hematologic malignancies. Clinical, radiographic data, bronchoscopic sampling techniques and diagnostic results were recorded. Initially undiagnostic patients were followed up for 2 years for a definitive diagnosis.

RESULTS

Of 224 patients included, 179 (79.9%) were confirmed with active thoracic malignancies. BAL diagnostic yield of cancer based on different radiographic characters of target lesion are as follow: isolated lymphadenopathies 0%, central lesions 45.5%, peripheral masses (diameter ≥3 cm) 21.4%, peripheral large nodules (2≤ diameter <3 cm) 15.8%, and peripheral small nodules (diameter <2 cm) 7.1%, while composite bronchoscopy achieved diagnostic yield of 93.3%, 95.5%, 91.7%, 76.9%, and 66.7% in corresponding lesion types. No cancer was diagnosed solely by BAL-cytology. Proportions of patients with positive BAL culture did not differ significantly between patients with and without pre-test suspicion for infections (P=0.199). In multivariable analysis, infections were associated with age ≥75 (OR 3.0; 95% CI: 1.29-7.06), chronic obstructive pulmonary disease (COPD) (OR 2.7; 95% CI: 1.14-6.26) and diabetes mellitus (DM) (OR 4.5; 95% CI: 1.90-10.44).

CONCLUSIONS

Omitting BAL cytology in settings of comprehensive bronchoscopy may not compromise cancer diagnosis. For patients primarily suspected with thoracic malignancy, performing BAL culture only based on clinical suspicion could miss important infectious etiology.

Respiratory bacterial culture from two sequential bronchoalveolar lavages of the same lobe in children with chronic cough

Identification of bacteria causing lower-airway infections is important to determine appropriate antimicrobial therapy. Flexible bronchoscopy with bronchoalveolar lavage (BAL) is used to obtain lower-airway specimens in young children. The first lavage (lavage-1) is typically used for bacterial culture. However, no studies in children have compared the detection of cultivable bacteria from sequential lavages of the same lobe. BAL fluid was collected from two sequential lavages of the same lobe in 79 children enrolled in our prospective studies of chronic cough. The respiratory bacteria Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and Haemophilus parainfluenzae were isolated and identified using standard published methods. H. influenzae was differentiated from Haemophilus haemolyticus using PCR assays. Lower-airway infection was defined as ≥ 104 c.f.u. ml- 1 BAL fluid. We compared cultivable bacteria from lavage-1 with those from the second lavage (lavage-2) using the κ statistic. Lower-airway infections by any pathogen were detected in 46% of first lavages and 39% of second lavages. Detection was similar in both lavages for all pathogens; the κ statistic was 0.7-0.8 for all bacteria except H. parainfluenzae. Of all infections detected in either lavage, 90% were detected in lavage-1 and 78  in lavage-2. However, culture of lavage-2 identified infections that would have been missed in 8% of children, including infections by additional Streptococcus pneumoniae serotypes. Our findings support the continued use of lavage-1 for bacterial culture; however, culture of lavage-2 may yield additional identifications of bacterial pathogens in lower-airway infections.

Bacteria in COPD; their potential role and treatment

The role of bacterial infection in chronic obstructive pulmonary disease (COPD) and how it should be treated has been an ongoing source of controversy. For many years bacterial infection has not been thought to have an important effect in the pathology of this condition. Recent advances in diagnostic techniques, particularly the use 16S sequencing has demonstrated that there are a large range of bacteria present in the lower respiratory tract, both in terms of exacerbations and chronic colonization. A proportion of the bacteria present in the lower respiratory have also been shown to produce inflammation and hence are likely to be relevant for the pathogenesis of COPD. The accurate diagnosis of bacterial infection in individual patients remains a major challenge. The trials that have assessed the effect of antibiotics in COPD have generally been of low quality and have not been placebo controlled. Recent studies of macrolides for long-term treatment in COPD have found significantly reduced rates of exacerbations. Major challenges remain in accurately defining the potential role of bacteria in the inflammatory process and how best to optimize the use of antibiotics without the overuse of this limited resource. Alternative strategies to treat infection in COPD remain very limited.

Diagnostic bronchoscopy in solid-organ and hematopoietic stem cell transplantation

Fiberoptic bronchoscopy is a valuable diagnostic tool in solid-organ and hematopoietic stem cell transplant recipients presenting with a range of pulmonary complications. This article provides a comprehensive overview of the utility and potential adverse effects of diagnostic bronchoscopy for transplant recipients. Recommendations are offered on the selection of patients, the timing of bronchoscopy, and the samples to be obtained across the spectrum of suspected pulmonary complications of transplantation. Based on review of the literature, the authors recommend early diagnostic bronchoscopy over empiric treatment in transplant recipients with evidence of certain acute, subacute, or chronic pulmonary processes. This approach may be most critical when an underlying infectious etiology is suspected. In the absence of prompt diagnostic information on which to base effective treatment, the risks associated with empiric antimicrobial therapy, including medication side effects and the development of antibiotic resistance, compound the potential harm of delaying targeted management.

In young children, persistent wheezing is associated with bronchial bacterial infection: a retrospective analysis

Background

Young children with persistent wheezing pose a diagnostic and therapeutical challenge to the pediatrician.

We aimed to evaluate bacterial bronchial infection as a possible reason for non response to conventional asthma therapy, and to identify and characterise the predominant pathogens involved.

Methods

We retrospectively analysed microbiological and cytological findings in a selected population of young wheezers with symptoms unresponsive to inhaled corticosteroid (ICS) therapy, who underwent flexible bronchoscopy with bronchoalveolar lavage (BAL). Procedural measures were taken to limit contamination risk and quantitative bacterial culture of BAL fluid (significance cut-off ≥ 10⁴ colony-forming units/ml) was used. Modern microbiological methods were used for detection of a wide panel of pathogens and for characterisation of the bacterial isolates.

Results

33 children aged between 4 and 38 months, without structural anomalies of the conductive airways were evaluated. Significant bacterial BAL cultures were found in 48,5 % of patients. Haemophilus influenzae was isolated in 30,3 %, Streptococcus pneumoniae in 12,1 % and Moraxella catarrhalis in 12,1 %. All H. influenzae isolates were non-encapsulated strains and definitely distinguished from non-haemolytic H. haemolyticus. Respiratory viruses were detected in 21,9 % of cases with mixed bacterial-viral infection in 12,1 %. Cytology revealed a marked neutrophilic inflammation.

Conclusions

Bacterial infection of the bronchial tree is common in persistent preschool wheezers and provides a possible explanation for non response to ICS therapy. Non-typeable H. influenzae seems to be the predominant pathogen involved, followed by S. pneumoniae and M. catarrhalis.

Microbiology of bronchoalveolar lavage fluid in children with acute nonresponding or recurrent community-acquired pneumonia: identification of nontypeable Haemophilus influenzae as a major pathogen

Background. Precise etiologic diagnosis in pediatric community-acquired pneumonia (CAP) remains challenging.

Methods. We conducted a retrospective study of CAP etiology in 2 groups of pediatric patients who underwent flexible bronchoscopy (FOB) with bronchoalveolar lavage (BAL); children with acute nonresponsive CAP (NR-CAP; n = 127) or recurrent CAP (Rec-CAP; n = 123). Procedural measures were taken to limit contamination risk and quantitative bacterial culture of BAL fluid (significance cutoff point, ≥10⁴ colony-forming units/mL) was used. Blood culture results, serological test results, nasopharyngeal secretion findings, and pleural fluid culture results were also assessed, where available.

Results. An infectious agent was detected in 76.0% of cases. In 51.2% of infections, aerobic bacteria were isolated, of which 75.0%, 28.9%, and 13.3% were Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae, respectively. Most (97.9%) of the H. influenzae strains were nontypeable (NTHi). H. influenzae was detected in 26.0% of NR-CAP cases and 51.2% of Rec-CAP cases, whereas Mycoplasma pneumoniae was the predominant pathogen in the NR-CAP group (accounting for 34.9% of cases) but not in the Rec-CAP group (19.3%). Viruses were found in 30.4% of cases, with respiratory syncytial virus, parainfluenzaviruses, and influenzaviruses detected most frequently. Mixed infections were found in 18.9% of NR-CAP cases and 30.1% of Rec-CAP cases.

Conclusions. A variety of microorganisms were isolated with frequent mixed infection. NTHi was one of the major pathogens found, especially in association with recurrent CAP, possibly because of improved detection with the FOB with BAL procedure. This suggests that the burden of pediatric CAP could be reduced by addressing NTHi as a major causative pathogen.

Early fiberoptic bronchoscopy during non-invasive ventilation in patients with decompensated chronic obstructive pulmonary disease due to community-acquired-pneumonia

INTRODUCTION

Inefficient clearance of copious respiratory secretion is a cause of non-invasive positive pressure ventilation (NPPV) failure, especially in chronic respiratory patients with community-acquired-pneumonia (CAP) and impaired consciousness. We postulated that in such a clinical scenario, when intubation and conventional mechanical ventilation (CMV) are strongly recommended, the suction of secretions with fiberoptic bronchoscopy (FBO) may increase the chance of NPPV success. The objective of this pilot study was, firstly, to verify the safety and effectiveness of early FBO during NPPV and, secondly, to compare the hospital outcomes of this strategy versus a CMV-based strategy in patients with decompensated chronic obstructive pulmonary disease (COPD) due to CAP who are not appropriate candidates for NPPV because of inefficient mucous clearance and hypercapnic encephalopathy (HE).

METHODS

This is a 12-month prospective matched case-control study performed in one respiratory semi-intensive care unit (RSICU) with expertise in NPPV and in one intensive care unit (ICU). Fifteen acutely decompensated COPD patients with copious secretion retention and HE due to CAP undergoing NPPV in RSICU, and 15 controls (matched for arterial blood gases, acute physiology and chronic health evaluation score III, Kelly-Matthay scale, pneumonia extension and severity) receiving CMV in the ICU were studied.

RESULTS

Two hours of NPPV significantly improved arterial blood gases, Kelly and cough efficiency scores without FBO-related complications. NPPV avoided intubation in 12/15 patients (80%). Improvement in arterial blood gases was similar in the two groups, except for a greater PaO2/fraction of inspired oxygen ratio with CMV. The rates of overall and septic complications, and of tracheostomy were lower in the NPPV group (20%, 20%, and 0%) versus the CMV group (80%, 60%, and 40%; P < 0.05). Hospital mortality, duration of hospitalisation and duration of ventilation were similar in the two groups.

CONCLUSIONS

In patients with decompensated COPD due to CAP who are candidates for CMV because of HE and inability to clear copious secretions, NPPV with early therapeutic FBO performed by an experienced team is a feasible, safe and effective alternative strategy.

Is quantitative PCR for the pneumolysin (ply) gene useful for detection of pneumococcal lower respiratory tract infection?

The pneumolysin (ply) gene is widely used as a target in PCR assays for Streptococcus pneumoniae in respiratory secretions. However, false-positive results with conventional ply-based PCR have been reported. The aim here was to study the performance of a quantitative ply-based PCR for the identification of pneumococcal lower respiratory tract infection (LRTI). In a prospective study, fibreoptic bronchoscopy was performed in 156 hospitalized adult patients with LRTI and 31 controls who underwent bronchoscopy because of suspicion of malignancy. Among the LRTI patients and controls, the quantitative ply-based PCR applied to bronchoalveolar lavage (BAL) fluid was positive at >or=10(3) genome copies/mL in 61% and 71% of the subjects, at >or=10(5) genome copies/mL in 40% and 58% of the subjects, and at >or=10(7) genome copies/mL in 15% and 3.2% of the subjects, respectively. Using BAL fluid culture, blood culture, and/or a urinary antigen test, S. pneumoniae was identified in 19 LRTI patients. As compared with these diagnostic methods used in combination, quantitative ply-based PCR showed sensitivities and specificities of 89% and 43% at a cut-off of 10(3) genome copies/mL, of 84% and 66% at a cut-off of 10(5) genome copies/mL, and of 53% and 90% at a cut-off of 10(7) genome copies/mL, respectively. In conclusion, a high cut-off with the quantitative ply-based PCR was required to reach acceptable specificity. However, as a high cut-off resulted in low sensitivity, quantitative ply-based PCR does not appear to be clinically useful. Quantitative PCR methods for S. pneumoniae using alternative gene targets should be evaluated.

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.

Intensified microbiological investigations in adult patients admitted to hospital with lower respiratory tract infections

The objective of this study was to investigate the diagnostic yield of a programme with intensified microbiological investigations in immunocompetent adult patients with lower respiratory tract infections (LRTI). Patients in the study group were included prospectively and consecutively from September 1st 1997 to May 31st 1998 and were compared with a control group from the preceding year. A total of 67 adult patients were included in the study group and they were compared with 122 adult patients in the control group. The study group underwent fibre-optic bronchoscopy (FOB) with bronchoalveolar lavage (BAL). Only 7% in the historic control group were discharged with an aetiological diagnosis of their infections; while the diagnostic yield in the study group increased to 51% of patients. In the study group the presence of new infiltrates on chest X-ray increased the detection of a microbiological aetiology from 37% with no infiltrates to 62% with infiltrates and recent antibiotic therapy reduced the detection of a microbiological cause of infection from 61% in 36 patients who had not received antibiotic therapy to 39% in 31 patients who had received recent antibiotic therapy prior to microbiological sampling. Patients in the study group with known aetiology had higher values of inflammatory markers than patients with unknown aetiology. For Streptococcus pneumoniae infection culture and urine antigen detection were complimentary depending on recent antibiotic therapy since seven of eight culture-positive patients had not received antibiotic therapy within 72 h prior to investigation, while all four patients positive for urine antigens from S. pneumoniae had received antibiotic therapy within 72 h of urine sampling. In conclusion intensified microbiologic investigations increase the diagnostic yield from 7% to 51% of patients in the study group with an aetiologic diagnosis. Routine FOB with BAL had no apparent effect on clinical outcome and seems only justified in selected patients with severe LRTI with infiltrates on chest X-ray and signs of severe inflammation where a high diagnostic yield is achieved.