A prospective study of community-acquired pneumonia in Hong Kong

Diagnostic value of the neutrophil lymphocyte ratio in discrimination between tuberculosis and bacterial community acquired pneumonia: A meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis, based on Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, to evaluate current literature on diagnostic value of neutrophil to lymphocyte ratio (NLR) in discrimination between tuberculosis (TB) and bacterial community acquired pneumonia (B-CAP).

METHODS

Literature search was conducted from July 20, 2023 using Scopus, PubMed, and Web of Science databases. STATA software (version 12.0; Stata Corporation) was used for all analyses.

RESULTS

We found that patients with TB had significantly lower levels of NLR compared to those with B-CAP (SMD = -1.09, 95 %CI = -1.78- -0.40, P = 0.002). In the quality subgroup analysis, we found that patients with TB had significantly lower level of NLR compared to those with B-CAP consistent in moderate (SMD = -0.86, 95 %CI = -2.30, 0.57, P = 0.23) and high-quality studies (SMD = -1.25, 95 %CI = -2.07, -0.42). In the subgroup analysis based on continent, we found that patients with TB had significantly lower level of NLR compared to those with B-CAP in studies performed in Asian populations (SMD = -1.37, 95 %CI = -2.13, -0.61, P < 0.001), but not on African population (SMD = -0.02, 95 %CI = -1.06, 1.02, P = 0.97). The result of this study did not change after execution of sensitivity analysis. The pooled sensitivity of NLR was 0.86 (95% CI = 0.80, 0.91), and the pooled specificity was0.88 (95% CI = 0.69, 0.95).

CONCLUSION

Patients with TB had a significantly lower NLR levels compared to those with B-CAP, so we utilized this biomarker for distinguishing between the disorders.

High-resolution computed tomography features associated with differentiation of tuberculosis among elderly patients with community-acquired pneumonia: a multi-institutional propensity-score matched study

While high-resolution computed tomography (HRCT) is increasingly performed, its role in diagnosing pulmonary tuberculosis (TB) among elderly patients with community-acquired pneumonia (CAP) has not been fully elucidated. This study aimed to determine HRCT features that can differentiate pulmonary TB from non-TB CAP in elderly patients. This study included consecutive elderly patients (age > 65 years) admitted to two teaching hospitals for pulmonary TB or non-TB pneumonia who met the CAP criteria of the American Thoracic Society/Infectious Diseases Society of America guidelines. After propensity score matching for clinical background between patients with pulmonary TB and those with non-TB CAP, their HRCT features were compared. This study included 151 patients with pulmonary TB and 238 patients with non-TB CAP. The presence of centrilobular nodules, air bronchograms, and cavities and the absence of ground-glass opacities and bronchial wall thickening were significantly associated with pulmonary TB. The negative predictive values of centrilobular nodules, air bronchograms, and cavities for pulmonary TB were moderate (70.6%, 67.9%, and 63.0%, respectively), whereas the positive predictive value of cavities was high (96.6%). In elderly patients, although some HRCT features could differentiate pulmonary TB from non-TB CAP, no useful findings could rule out pulmonary TB with certainty.

Clinical features of atypical tuberculosis mimicking bacterial pneumonia

OBJECTIVES

The aim of this study is to investigate clinical features of atypical pulmonary tuberculosis (aPTB) mimicking bacterial pneumonia, determine imaging features with the highest degree of correlation, and identify predictors for acid-fast bacilli (AFB) positivity.

METHODS

The clinical data of 259 patients considered as aPTB were retrospectively analyzed. The correlation of CT patterns was evaluated with Spearman analysis, and the predictors for AFB positivity were assessed with the multivariate analysis.

RESULTS

The most common symptom of aPTB was cough (84.6%), followed by fever and anorexia (47.1 and 41.7%, respectively). Infiltrated patchy was the most common radiological pattern (84.9%), followed by nodules (3-10 mm), micronodules (<3 mm), and consolidation (79.2, 78.8, and 66.0%, respectively). Nodules (3-10 mm) and micronodules (r = 0.988, p < 0.001), consolidation and air bronchogram (r = 0.590, p < 0.001), and pulmonary atelectasis and consolidation (r = 0.323, p < 0.001) showed high correlation. In the multivariate analysis, hyperpyrexia (OR, 2.29; 95% CI, 1.22-4.29) and bronchiectasis (OR, 2.06; 95% CI, 1.04-4.06) were the predictors of AFB-smear positivity, while bulla (OR, 0.22; 95% CI, 0.05-0.97) was the predictor of AFB-smear negativity.

CONCLUSION

This study demonstrated the clinical and radiological features of aPTB mimicking pneumonia. Several paired radiological findings may guide us to the diagnosis of aPTB. Hyperpyrexia and bronchiectasis may be helpful for predicting AFB positivity, and bulla may be a predictive sign of AFB negativity.

Computed tomography-based predictive nomogram for differentiating primary progressive pulmonary tuberculosis from community-acquired pneumonia in children

Background

To investigate the value of predictive nomogram in optimizing computed tomography (CT)-based differential diagnosis of primary progressive pulmonary tuberculosis (TB) from community-acquired pneumonia (CAP) in children.

Methods

This retrospective study included 53 patients with clinically confirmed pulmonary TB and 62 patients with CAP. Patients were grouped at random according to a 3:1 ratio (primary cohort n = 86, validation cohort n = 29). A total of 970 radiomic features were extracted from CT images and key features were screened out to build radiomic signatures using the least absolute shrinkage and selection operator algorithm. A predictive nomogram was developed based on the signatures and clinical factors, and its performance was assessed by the receiver operating characteristic curve, calibration curve, and decision curve analysis.

Results

Initially, 5 and 6 key features were selected to establish a radiomic signature from the pulmonary consolidation region (RS1) and a signature from lymph node region (RS2), respectively. A predictive nomogram was built combining RS1, RS2, and a clinical factor (duration of fever). Its classification performance (AUC = 0.971, 95% confidence interval [CI]: 0.912–1) was better than the senior radiologist’s clinical judgment (AUC = 0.791, 95% CI: 0.636-0.946), the clinical factor (AUC = 0.832, 95% CI: 0.677–0.987), and the combination of RS1 and RS2 (AUC = 0.957, 95% CI: 0.889–1). The calibration curves indicated a good consistency of the nomogram. Decision curve analysis demonstrated that the nomogram was useful in clinical settings.

Conclusions

A CT-based predictive nomogram was proposed and could be conveniently used to differentiate pulmonary TB from CAP in children.

Electronic supplementary material

The online version of this article (10.1186/s12880-019-0355-z) contains supplementary material, which is available to authorized users.

Why is the rate of pneumococcal pneumonia declining?

PURPOSE OF REVIEW

As Streptococcus pneumoniae was considered the etiological agent of nearly all the cases of pneumonia at the beginning of the 20th century, and today is identified in fewer than 10-15% of cases, we analyze the possible causes of such a decline.

RECENT FINDINGS

Extensive use of early empiric antimicrobial therapy, discovery of previously unrecognized pathogens, availability to newer diagnostic methods for the recognition of the pneumonia pathogens (PCR, urinary antigens, monoclonal antibodies etc.) and of improved preventive measures, including vaccines, are some of possible explanations of the declining role of S. pneumoniae in the cause of pneumonia.

SUMMARY

The 14-valent and the 23-valent capsular polysaccharide pneumococcal vaccines were licensed in 1977 and 1983, respectively. The seven-valent protein-conjugated capsular polysaccharide vaccine, approved for routine use in children starting at 2 months of age, was highly effective in preventing invasive pneumococcal disease in children but also in adults because of the herd effect. In 2010, the 13-valent protein-conjugated capsular polysaccharide vaccine replaced seven-valent protein-conjugated capsular polysaccharide vaccine. With the use of conjugated vaccines, a decrease of the vaccine-type invasive pneumococcal disease for all age groups was observed. Both the direct effect of the vaccine and the so-called herd immunity are considered responsible for much of the decline.

Etiology and epidemiology of community-acquired pneumonia in adults requiring hospital admission: A prospective study in rural Central Philippines

BACKGROUND

Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality among adults worldwide. However, the distribution of the etiology of CAP varies from one country to another, with limited data from rural areas.

METHODS

A prospective hospital-based study on adult CAP was conducted in Leyte, Central Philippines from May 2010 to May 2012. Blood, sputum, and nasopharyngeal samples obtained from patients were used to identify pathogens using standard microbiological culture methods and PCR.

RESULTS

Of the 535 patients enrolled, 38% were younger than 50 years old. More than half of the patients had an underlying disease, including pulmonary tuberculosis (22%). The detection rate was higher for bacteria (40%) than viruses (13%). Haemophilus influenzae (12%) was the most commonly detected bacterium and influenza virus (5%) was the most commonly detected virus. The proportion of CAP patients with Mycobacterium tuberculosis infection was higher in the younger age group than in the older age group. Among CAP patients, 14% died during hospitalization, and drowsiness on admission and SpO₂ <90% were independent risk factors for mortality.

CONCLUSIONS

Bacterial infections contribute substantially to the number of hospitalizations among CAP patients in rural Philippines. This study also highlights the importance of treatment of tuberculosis in reducing the burden of adult CAP in the country.

Distribution of 13-Valent pneumococcal conjugate vaccine serotype streptococcus pneumoniae in adults 50 Years and Older presenting with community-acquired pneumonia in Israel

BACKGROUND

Community acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide, and is a leading cause of hospitalization in previously healthy individuals without predisposing risk factors or comorbidities. In this study we determined PCV13 serotype distribution in adults aged ≥50 years with radiographically confirmed CAP in Israel.

METHODS

Subjects aged ≥50 years were enrolled from one of three hospitals (Emek Medical Center, Meir Medical Center and Sheba Medical Center) from March 2014 to July 2015. Information was collected on subject demographics, comorbidities, risk factors, and pneumococcal vaccine immunization status. Subjects presented with suspected CAP supported by radiographic evidence, and provided a urine sample and informed consent. Subjects without radiographic confirmation of CAP or who received PPSV23 within 30 days of study enrollment were excluded from the final analysis. Serotype distribution was performed using the urinary antigen detection (UAD) assay and/or microbiological culture.

RESULTS

Overall, 498 subjects with radiographically confirmed CAP were enrolled in the study. Eighty subjects (16.1%) were positive for any S. pneumoniae serotype by ≥1 assay, and 38 (7.6%) were positive for PCV13 serotypes via the UAD. The overall 30-day mortality rate was 1.2%, though S. pneumoniae was not isolated from any case leading to death.

CONCLUSION

Despite six years of high pneumococcal immunization coverage in children in Israel, we have shown that 7.6% of CAP cases among adults in Israel remain related to PCV13 serotypes; and that the burden of PCV13 may be as high as 47% of observed pneumococcal CAP.

Acute respiratory distress syndrome complicating community-acquired pneumonia secondary to mycobacterium tuberculosis in a tertiary care center in Saudi Arabia

Objectives:

To discuss our center’s experience with acute respiratory distress syndrome (ARDS) secondary to pulmonary tuberculosis (TB) in a major tertiary referral hospital in the Kingdom of Saudi Arabia.

Methods:

A retrospective review of medical records of all patients with community-acquired pneumonia secondary to mycobacterium TB infection who were admitted for critical care in a single center of King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia from 2004 to 2013.

Results:

In our review of 350 patients with community-acquired pneumonia admitted to Intensive Care Unit, 11 cases of TB complicated with ARDS were identified. The mean age of patients was 51.9 years. The median time from hospital admission to pulmonary TB diagnosis and start of therapy was 5 days, while the median time from onset of symptoms to initiation of treatment was 18 days. The mortality rate was 64%, and the median length of hospital stay before death was 21.4 days. Delayed treatment, as well as high acute physiology and chronic health evaluation II and CURB-65 scores at presentation, were independent risk factors for death.

Conclusion:

Patients with pulmonary TB infrequently present to intensive care with acute symptoms that meet all criteria for ARDS. Such a presentation of TB carries a high mortality risk.

[First epidemiologic data on pneumonia in Cambodia]

About 15% of deaths in adults are related to lung infections in Cambodia. Some knowledge on microbial epidemiology is crucial for deciding first-line antibiotic treatment. However, to date, these data are not available in Cambodia. Consequently, antibiotic prescription relies on French or neighborhood's countries guidelines, which are possibly not suitable. This cases-series aimed to provide data on microbial ecology in pneumonia. Medical charts of patients newly admitted for lung infection in the pulmonology unit of Preah Kossamak Hospital were retrospectively reviewed. Ninety-four patients were included and 29% had a complete microbiological diagnosis. Main germs isolated were: Gram-negative bacilli (n=20; 70.4%) and M. tuberculosis infections (n=7; 25.9%). There was one case of myeloïdosis. No S. pneumonia was isolated, possibly due to sample shipping tropical conditions. Antibiograms showed high resistance profiles. Although this study bring new data in the field, it also showed that European guidelines for antibiotic are not relevant in such countries and stress the need for further dedicated and prospective studies.

The bacterial aetiology of adult community-acquired pneumonia in Asia: a systematic review

BACKGROUND

Community-acquired pneumonia (CAP) is a major cause of adult mortality in Asia. Appropriate empirical treatment depends on knowledge of the pathogens commonly responsible. However, assessing the aetiological significance of identified organisms is often difficult, particularly with sputum isolates that might represent contamination with oropharyngeal flora.

METHODS

A systematic review of all adult CAP aetiology studies from Asia, excluding the Middle East, published in English between 1 January 1990 and 1 March 2012 was conducted. Forty-eight studies reporting on 10 423 patients were included, representing data from China, India, Indonesia, Japan, Malaysia, The Philippines, Singapore, South Korea, Taiwan, Thailand and Vietnam. Data from large parts of Asia were unavailable and there was substantial heterogeneity in methodology.

RESULTS

As in western studies, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella spp. and Haemophilus influenzae were all significant pathogens. However, compared with western studies, S. pneumoniae was of less relative importance. Gram-negative bacilli and Mycobacterium tuberculosis were more important, and in northeast Thailand Burkholderia pseudomallei was a major pathogen.

CONCLUSION

These data have major implications for diagnostic strategies and empirical treatment. Narrow-spectrum antibiotics targeting S. pneumoniae may be inappropriate in many Asian settings, and agents active against TB may lead to partial response and delayed TB diagnosis.

Role of the neutrophil-lymphocyte count ratio in the differential diagnosis between pulmonary tuberculosis and bacterial community-acquired pneumonia

Background

Differential diagnosis between pulmonary tuberculosis (TB) and bacterial community-acquired pneumonia (CAP) is often challenging. The neutrophil-lymphocyte count ratio (NLR), a convenient marker of inflammation, has been demonstrated to be a useful biomarker for predicting bacteremia. We investigated the usefulness of the NLR for discriminating pulmonary TB from bacterial CAP in an intermediate TB-burden country.

Methods

We retrospectively analyzed the clinical and laboratory characteristics of 206 patients suspected of having pulmonary TB or bacterial CAP from January 2009 to February 2011. The diagnostic ability of the NLR for differential diagnosis was evaluated and compared with that of C-reactive protein.

Results

Serum NLR levels were significantly lower in patients with pulmonary TB than in patients with bacterial CAP (3.67±2.12 vs. 14.64±9.72, P<0.001). A NLR <7 was an optimal cut-off value to discriminate patients with pulmonary TB from patients with bacterial CAP (sensitivity 91.1%, specificity 81.9%, positive predictive value 85.7%, negative predictive value 88.5%). The area under the curve for the NLR (0.95, 95% confidence interval [CI], 0.91-0.98) was significantly greater than that of C-reactive protein (0.83, 95% CI, 0.76-0.88; P=0.0015).

Conclusions

The NLR obtained at the initial diagnostic stage is a useful laboratory marker to discriminate patients with pulmonary TB from patients with bacterial CAP in an intermediate TB-burden country.

Clinical and economic burden of community-acquired pneumonia amongst adults in the Asia-Pacific region

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity amongst adults in the Asia-Pacific region. Literature published between 1990 and May 2010 on the clinical and economic burden of CAP amongst adults in this region was reviewed. CAP is a significant health burden with significant economic impact in this region. Chronic obstructive pulmonary disease, cardiovascular disease, diabetes mellitus and advanced age were risk factors for CAP. Aetiological agents included Streptococcus pneumoniae, Klebsiella pneumoniae, Gram-negative bacteria, Mycobacterium tuberculosis, Burkholderia pseudomallei, Staphylococcus aureus and atypical pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella spp.), with important differences in the prevalence of these pathogens within the region. Antibiotic resistance was significant but was not linked to excess mortality. Aetiological pathogens remained susceptible to newer antimicrobial agents. Rational antibiotic use is essential for preventing resistance, and increased surveillance is required to identify future trends in incidence and aetiology and to drive treatment and prevention strategies.

Respiratory infections unique to Asia

Asia is a highly heterogeneous region with vastly different cultures, social constitutions and populations affected by a wide spectrum of respiratory diseases caused by tropical pathogens. Asian patients with community‐acquired pneumonia differ from their Western counterparts in microbiological aetiology, in particular the prominence of Gram‐negative organisms, Mycobacterium tuberculosis, Burkholderia pseudomallei and Staphylococcus aureus. In addition, the differences in socioeconomic and health‐care infrastructures limit the usefulness of Western management guidelines for pneumonia in Asia. The importance of emerging infectious diseases such as severe acute respiratory syndrome and avian influenza infection remain as close concerns for practising respirologists in Asia. Specific infections such as melioidosis, dengue haemorrhagic fever, scrub typhus, leptospirosis, salmonellosis, penicilliosis marneffei, malaria, amoebiasis, paragonimiasis, strongyloidiasis, gnathostomiasis, trinchinellosis, schistosomiasis and echinococcosis occur commonly in Asia and manifest with a prominent respiratory component. Pulmonary eosinophilia, endemic in parts of Asia, could occur with a wide range of tropical infections. Tropical eosinophilia is believed to be a hyper‐sensitivity reaction to degenerating microfilariae trapped in the lungs.

This article attempts to address the key respiratory issues in these respiratory infections unique to Asia and highlight the important diagnostic and management issues faced by practising respirologists.

A one-year prospective study of infectious etiology in patients hospitalized with acute exacerbations of COPD and concomitant pneumonia

AIM

This study assessed the infectious etiology of patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with concomitant pneumonia.

METHODS

Patients admitted to medical wards in an acute hospital were recruited prospectively from May 1, 2004 to April 30, 2005. Sputum culture, blood culture, paired serology, and nasopharyngeal aspirates (NPA) viral culture and polymerase chain reaction (PCR) studies were performed. Spirometry was assessed in stable phase at 2-3 months post-hospital discharge.

RESULTS

Seventy eight subjects were admitted for AECOPD with concomitant pneumonia. The mean (SD) age was 77.1 (7.5) years, with FEV(1) of 41.5 (20.8)% predicted normal. Overall, an infectious etiology could be established in 48.7% of the subjects. Among the 71 subjects with sputum collected, 40.8% had positive bacterial culture. The commonest bacteria identified were Streptococcus pneumoniae (8[11.3%]), Pseudomonas aeruginosa (7[9.9%]) and Haemophilus influenzae (7[9.9%]). Among the 66 subjects with NPA collected, 9.0 and 12.2% had positive viral culture and PCR results, respectively. The commonest viruses identified by NPA PCR were influenza A (4[6.1%] subjects) and rhinovirus (2[3.0%]). Paired serology was positive in 4.4%. Patients on high dose inhaled corticosteroid (ICS) (>1000 mcg beclomethasone-equivalent/day) had a higher rate of positive sputum bacterial culture than those on low-medium dose of ICS (50.0% vs 18.2%, p=0.02).

CONCLUSION

An infectious etiology could be established in about half of patients hospitalized with AECOPD and concomitant pneumonia. The majority of identifiable causes were bacterial. Patients on high dose ICS might have impaired airway defense as reflected by the higher rate of positive sputum culture.

Pulmonary tuberculosis presenting as community-acquired pneumonia

OBJECTIVE AND BACKGROUND

The aims of this study were to investigate the frequency of Mycobacterium tuberculosis as a cause of community-acquired pneumonia (CAP) requiring hospitalization in Malaysia, and to define the clinical features of pulmonary tuberculosis (PTB) that distinguish it from non-TB CAP.

METHODS

A prospective study was performed on consecutive non-immunocompromised patients aged 12 years and older, who were hospitalized for CAP.

RESULTS

Of a total of 346 patients hospitalized for CAP, the aetiological agent was identified in 163 patients (47.1%). M. tuberculosis was isolated in 17 patients (4.9%). Multivariate analysis revealed that the following features were significantly associated with culture-positive PTB: duration of symptoms of more than 2 weeks before hospital admission (odds ratio (OR) 25.10; 95% confidence interval (CI) 4.63-136.05; P<0.001), history of night sweats (OR 5.43; 95% CI 1.10-26.79; P=0.038), chest radiograph showing upper lobe involvement (OR 8.23; 95% CI 1.59-42.53; P=0.012) or cavitary infiltrates (OR 19.41; 95% CI 2.94-128.19; P=0.002), total white blood cell count on admission of 12x10(9)/L or less (OR 6.28; 95% CI 1.21-32.52; P=0.029) and lymphopenia (OR 4.73; 95% CI 1.08-20.85; P=0.040).

CONCLUSION

Mycobacterium tuberculosis was not an uncommon cause of CAP requiring hospitalization in Malaysia. A longer duration of symptoms, history of night sweats, upper lobe involvement, cavitary infiltrates, lower total white blood cell count and lymphopenia were predictive of PTB.

[Definition of low respiratory tract infections]

Lower respiratory tract infection is easily suggested on clinical signs (cough and sputum) associated with fever. To discriminate between pneumonia and acute bronchitis is crucial because of the mortality associated with pneumonia and of its specific management. Chest X-ray is a key exam for the diagnosis and should be performed on the basis of validated clinical signs that are however of weak diagnostic value. Clinical as well as radiological signs cannot be reliably used to identify the causative germ. Sputum examination, the search for pneumococcal and legionella urinary antigens are of good diagnostic value. An associated COPD may lead to an acute respiratory failure. Acute exacerbation of chronic bronchitis results from various causes but infection is involved in about 50% of the cases, mostly viral and most often due to a rhinovirus. Viral infection can be associated to bacterial infection and the most frequently isolated germs are Streptococcus pneumoniae, Haemophilus influenzae, and B. catarrhalis. Severity assessment relies on the value of basal FEV1 that is often non available. Therefore Afssaps suggests using a dyspnea index to assess exacerbation severity.

Sputum bacteriology in patients hospitalized with acute exacerbations of chronic obstructive pulmonary disease and concomitant pneumonia in Hong Kong

AIM

To study the sputum microbiology of patients admitted to a teaching hospital with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with concomitant pneumonia.

METHODS

This was a retrospective study in a tertiary university hospital in Hong Kong. All episodes of AECOPD with pneumonia, patient demographics, length of stay, sputum culture and radiological results admitted in the first half of the year 2000 were retrieved from hospital records.

RESULTS

There were 118 patients (91 male) with 150 episodes of AECOPD with concomitant pneumonia. The age of the patients was 74.8 +/- 10.0 years. Positive routine sputum culture was detected in 45.6% of the patients. Among these hospital admissions, 8.7, 4.0 and 12.0%, respectively, required intensive care unit admissions, mechanical ventilation and non-invasive positive pressure ventilation. Haemophilus influenzae was the commonest organism found in sputum (26.0%), followed by Pseudomonas aeruginosa (5.5%), Streptococcus pneumoniae (3.4%), and Moraxella catarrhalis (3.4%). Mycobacterium tuberculosis was found in 1.5% of the admissions. The presence of P. aeruginosa in sputum was associated with a longer hospital length of stay (9.1 +/- 3.1 vs. 7.1 +/- 4.2 days, P = 0.03).

CONCLUSION

In contrast to most other studies reporting S. pneumoniae as the most likely bacterial pathogen, H. influenzae was the commonest bacterium isolated in sputum in our patients with AECOPD and concomitant pneumonia.

Sputum bacteriology in patients with acute exacerbations of COPD in Hong Kong

STUDY OBJECTIVE

To study the demographics and sputum microbiology of patients admitted to a teaching hospital with acute exacerbations of chronic obstructive pulmonary disease (AECOPD).

DESIGN

A retrospective study.

SETTING

A tertiary university hospital in Hong Kong.

PATIENTS

All episodes of AECOPD, patient demographics, length of stay, sputum culture and radiological results admitted in the first half of the year 2000 were retrieved from hospital records.

RESULTS

There were 329 patients with 418 episodes of AECOPD without concomitant pneumonia. The age of the patients was 74.4+/-8.3 years. The acute hospital length of stay for an episode of AECOPD was 7.3+/-6.5 days. Haemophilus influenzae was the commonest organism found in sputum (23.1%), followed by Pseudomonas aeruginosa (6.3%) and Streptococcus pneumoniae (4.0%). Mycobacterium tuberculosis was found in 1.1% of the admissions. Presence of organisms in sputum had no association with the hospital length of stay and intensive care unit admissions. In patients whose FEV1 was >50% of predicted values, there was a higher chance of positive sputum growth of H. influenzae than those with FEV1 <50% (16/44 vs. 31/162 episodes, respectively, P=0.02).

CONCLUSIONS

H. influenzae was the commonest bacterium isolated in sputum in patients with AECOPD. In areas endemic of tuberculosis, it is advisable to use fluoroquinolones for AECOPD with caution.

An Asian study on the prevalence of atypical respiratory pathogens in community-acquired pneumonia

BACKGROUND

In many parts of Asia, the inaccessibility and high cost of diagnostic tests have hampered the study of community-acquired pneumonia (CAP) caused by atypical respiratory pathogens.

OBJECTIVE

This surveillance study examined the frequency of infection with Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila in 1756 patients presenting with signs and symptoms of CAP at 12 medical centres in Asia, using standardised laboratory techniques and interpretation criteria in all participating centres.

METHODS

Diagnosis of current infection was based on significant changes in antibody titer or persisting high antibody titers, together with the presence of bacterial DNA in respiratory secretions, in the case of M. pneumoniae and C. pneumoniae infections, or bacterial antigen in urine, in the case of L. pneumophila serogroup 1 infection.

RESULTS

Using these criteria, results from 1374 patients with paired sera showed that, overall, 23.5% of CAP cases were associated with infection with atypical respiratory pathogens, with M. pneumoniae, C. pneumoniae, and L. pneumophila being found in 12.2%, 4.7%, and 6.6% of cases, respectively. Persisting high antibody titers indicative of past exposure to M. pneumoniae, C. pneumoniae, and L. pneumophila were seen in 10.2%, 4.8%, and 18.9% of patients, respectively.

CONCLUSION

These data reflect the overall high prevalence of these atypical pathogens among Asian patients with CAP.

Mycoplasma disease and acute chest syndrome in sickle cell disease

BACKGROUND

Acute chest syndrome (ACS) is the leading cause of hospitalization, morbidity, and mortality in patients with sickle cell disease. Radiographic and clinical findings in ACS resemble pneumonia; however, etiologies other than infectious pathogens have been implicated, including pulmonary fat embolism (PFE) and infarction of segments of the pulmonary vasculature. The National Acute Chest Syndrome Study Group was designed to identify the etiologic agents and clinical outcomes associated with this syndrome.

METHODS

Data were analyzed from the prospective study of 671 episodes of ACS in 538 patients with sickle cell anemia. ACS was defined as a new pulmonary infiltrate involving at least 1 complete segment of the lung, excluding atelectasis. In addition, the patients had to have chest pain, fever >38.5C, tachypnea, wheezing, or cough. Samples of blood and deep sputum were analyzed for evidence of bacteria, viruses, and PFE. Mycoplasma pneumoniae infection was determined by analysis of paired serologies. Detailed information on patient characteristics, presenting signs and symptoms, treatment, and clinical outcome were collected.

RESULTS

Fifty-one (9%) of 598 episodes of ACS had serologic evidence of M pneumoniae infection. Twelve percent of the 112 episodes of ACS occurring in patients younger than 5 years were associated with M pneumoniae infection. At the time of diagnosis, 98% of all patients with M pneumoniae infection had fever, 78% had a cough, and 51% were tachypneic. More than 50% developed multilobar infiltrates and effusions, 82% were transfused, and 6% required assisted ventilation. The average hospital stay was 10 days. Evidence of PFE with M pneumoniae infection was seen in 5 (20%) of 25 patients with adequate deep respiratory samples for the PFE assay. M pneumoniae and Chlamydia pneumoniae was found in 16% of patients with diagnostic studies for C pneumoniae. Mycoplasma hominis was cultured in 10 (2%) of 555 episodes of ACS and occurred more frequently in older patients, but the presenting symptoms and clinical course was similar to those with M pneumoniae.

CONCLUSIONS

M pneumoniae is commonly associated with the ACS in patients with sickle cell anemia and occurs in very young children. M hominis should be considered in the differential diagnosis of ACS. Aggressive treatment with broad-spectrum antibiotics, including 1 from the macrolide class, is recommended for all patients as well as bronchodilator therapy, early transfusion, and respiratory support when clinically indicated.

Community-acquired pneumonia--implementation of a prediction rule to guide selection of patients for outpatient treatment

The aim of this study was to determine the outcomes of outpatient treatment of community-acquired pneumonia (CAP) when a prediction rule was followed by emergency physicians to guide the selection of patients. This was a prospective observational study conducted at the emergency department of a university-affiliated hospital in Hong Kong, China. A clinical prediction rule was implemented to guide the selection of patients with CAP for outpatient treatment. All subsequent hospitalizations gial presentation were recorded, and the reasons were assessed. The utilization of the observation unit was incorporated into the treatment algorithm. Of 72 patients with CAP followed up as outpatients, 60 (83.3%) were treated successfully, nine (12.5%) required subsequent hospitalization within 30 days, and three (4.2%) were lost to follow-up. None of the patients died, and none required admission to the intensive care unit. Factors associated with subsequent hospitalization include: tuberculosis, underlying malignancy, persistent fever, comorbidity (rheumatoid arthritis and severe osteoporosis), intravenous drug addiction and alcoholism. The observation ward was utilized in 10 (16.7%) patients successfully treated as outpatients. It is concluded that the prediction rule can be safely implemented as a guide for emergency physicians. The short-stay observation unit may be usefully employed for treating low-risk CAP.

Community-acquired pneumonia in patients requiring hospitalization

OBJECTIVE

This study aimed to investigate the microbial aetiology of community-acquired pneumonia (CAP) in patients requiring hospitalization.

METHODOLOGY

A prospective study of consecutive non-immunocompromised patients aged 12 years and above admitted with CAP from August 1997 to May 1999 was undertaken.

RESULTS

Of 127 patients hospitalized for CAP, an aetiological diagnosis was achieved in 53 cases (41.7%). Klebsiella pneumoniae was the most frequently isolated pathogen and caused 10.2% of all the cases, followed by Streptococcus pneumoniae (5.5%), Haemophilus influenzae (5.5%), Mycoplasma pneumoniae (3.9%) and Pseudomonas aeruginosa (3.9%). Gram-negative bacilli were significantly more frequently identified in patients aged 60 years or older and in patients with comorbid illnesses. Twelve of 13 patients who died from CAP had other comorbid illnesses compared to 63 of 114 patients who survived (P = 0.014). Three of eight bacteraemic patients died compared with 10 of 119 non-bacteraemic patients (P = 0.035).

CONCLUSIONS

The microbiology of CAP in patients requiring hospitalization in Malaysia appears to be different from that in Western countries. Gram-negative bacilli were more frequently isolated in older patients and in those with comorbidity. Mortality from CAP is more likely in patients with comorbidity and in those who are bacteraemic.

Community-acquired pneumonia: etiology, epidemiology, and outcome at a teaching hospital in Argentina

OBJECTIVE

To survey the etiology and epidemiology of community-acquired pneumonia (CAP) in relation to age, comorbidity, and severity and to investigate prognostic factors.

DESIGN

Prospective epidemiologic study, single center.

SETTING

University hospital at Buenos Aires, Argentina.

PATIENTS

Outpatients and inpatients fulfilling clinical criteria of CAP.

INTERVENTIONS

Systematic laboratory evaluation for determining the etiology, and clinical evaluation stratifying patients into mild, moderate, and severe CAP (groups 1 to 3), a clinical rule used for hospitalization.

RESULTS

During a 12-month period, 343 patients (mean age, 64.4 years; range, 18 to 102 years) were evaluated. We found 167 microorganisms in 144 cases (yield, 42%). Streptococcus pneumoniae, the most common pathogen, was isolated in 35 cases (24%). Mycoplasma pneumoniae, present in 19 (13%), was second in frequency in group 1; Haemophilus influenzae, present in 17 cases (12%), was second in group 2; and Chlamydia pneumoniae, present in 12 cases (8%), was second in group 3. Etiology could not be determined on the basis of clinical presentation; identifying the etiology had no impact on mortality. Some findings were associated with specific causative organisms and outcome. A significantly lower number of nonsurvivors received adequate therapy (50% vs 77%).

CONCLUSIONS

Age, comorbidities, alcohol abuse, and smoking were related with distinct etiologies. PaO(2) to fraction of inspired oxygen ratio < 250, aerobic Gram-negative pathogen, chronic renal failure, Glasgow score < 15, malignant neoplasm, and aspirative pneumonia were associated with mortality by multivariate analysis. Local microbiologic data could be of help in tailoring therapeutic guidelines to the microbiologic reality at different settings. The stratification schema and the clinical rule used for hospitalization were useful.

Use of guidelines in treating community-acquired pneumonia

STUDY OBJECTIVES

Guidelines for empiric treatment of community-acquired pneumonia (CAP) have been developed to assist in prescribing appropriate antimicrobials. We studied utilization of guidelines developed by the American Thoracic, Canadian Infectious Diseases, and Canadian Thoracic Societies (ATS, CIDS, and CTS, respectively), physicians' familiarity with them, reasons that prompt deviation from them, and their effects on clinical outcomes.

DESIGN

Two-part observational study, with prospective and retrospective groups.

SETTING

A 1,100-bed, two-campus, tertiary-care teaching hospital.

PATIENTS AND PARTICIPANTS

Patients admitted to the general medical ward who were being treated empirically for CAP and housestaff who provided their care.

INTERVENTIONS

Medical residents reported on patients admitted to the hospital with CAP. The charts of all unreported patients admitted with CAP over the same period were reviewed.

MEASUREMENTS AND RESULTS

One hundred twenty-two patients were prospectively described and another 130 patients were identified retrospectively. There was no difference in guidelines adherence between the prospective and retrospective groups (81% compared with 80%; p=0.94). Deviation occurred most commonly in suspected aspiration. When physicians believed that they were following guidelines, this was true in 88%. When physicians believed that they were deviating, they were actually adhering in 46%. Guidelines adherence did not alter in-hospital mortality (12% compared with 14%, p=0.92) or length of hospitalization (median, 6 days for both groups).

CONCLUSIONS

ATS/CIDS/CTS guidelines for empiric treatment of CAP are widely used in our institution. Future amendments should address aspiration more explicitly. Residents' familiarity with them could be improved. Beneficial effects on outcomes remain unproven.

Tuberculosis is the commonest cause of pneumonia requiring hospitalization during Hajj (pilgrimage to Makkah)

The diagnosis and treatment of pneumonia in mass gathering situations is a medical challenge, requiring prompt decision making and knowledge of the aetiology. We studied cases of pneumonia admitted to two hospitals during the 1994 pilgrimage (Hajj) season to Makkah. Sixty-four patients were enrolled in the study, of which 47 (75%) were men with a mean age of 63 years (range 21-91). Nearly all were from developing countries. Diagnosis was established in 46 patients (72%) with Mycobacterium tuberculosis being the commonest causative organism (20%), followed by gram-negative bacilli (18.8%). Streptococcus pneumoniae accounted for only 10%, with Legionella pneumophilia, Mycoplasma pneumoniae, and viruses accounting each for 6%. The main finding of this study is that M. tuberculosis is a common cause of pneumonia under these unusual "extreme circumstances". Its presentation was acute and indistinguishable from pyogenic pneumonia. Thirty-one per cent of tuberculous cases had upper lobe involvement, 54% lower lobe, and 15% multi-lobar. This was similar to the radiographic features in non-tuberculous pneumonia cases. All but one patient with tuberculosis recovered following the administration of first-line anti-tuberculous drugs. The total mortality was 17%. The preponderance of M. tuberculosis and Gram-negative bacteria over S. pneumoniae may reflect the prior use of amoxycillin and the effect of exhaustion, malnutrition, and old age.

Practical considerations and guidelines for the management of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common condition which has a significant mortality. The management of a patient with CAP is centred around assessment and correction of gas exchange and fluid balance together with administration of appropriate antibiotics. Up to 10 different pathogens regularly cause CAP, of which Streptococcus pneumoniae is the most important. These different pathogens cannot be distinguished by clinical features or simple laboratory tests. Microbiological tests are slow and insensitive, so empirical therapy is necessary, at least initially. Accurate assessment of illness severity is the most important factor determining initial management, since this assists the decision of whether to admit the patient to hospital in addition to guiding antibiotic choice and route of administration. Two different approaches to severity assessment are outlined. Our antibiotic recommendation for empirical therapy for the patient managed at home and the previously fit patient admitted to hospital is amoxicillin. Amoxicillin/clavulanate plus a macrolide is our choice for the severely ill previously fit patient and a third-generation cephalosporin plus a macrolide is recommended for the severely ill patient with comorbidity. Alternative pathogens and specific treatment regimens are also described. There may be several causes of treatment failure, and in patients who fail to respond to therapy, it is essential to review all the initial clinical and laboratory information, which if necessary must be repeated.

Community acquired pneumonia in north eastern Australia--a hospital based study of aboriginal and non-aboriginal patients

BACKGROUND

Although the most important organism causing community acquired pneumonia continues to be Streptococcus pneumoniae, the frequency of other pathogens varies considerably across the world.

AIMS

To look for the causes of community acquired pneumonia (CAP) in north east Australia. To examine the differences between Aboriginal and non-Aboriginal subjects with emphasis on prevalence, risk factors, causative organisms and prognosis.

METHODS

The records of 200 consecutive patients admitted to Cairns Hospital during 1992 with a diagnosis of pneumonia were studied.

RESULTS

Aboriginal patients made up half the numbers admitted, but only 13% of the population. More Aboriginal adults died than non-Aboriginal adults, but no child died. Heavy alcohol use, chronic lung disease and diabetes mellitus were the commonest risk factors for Aborigines (alcohol, chronic lung disease and cancer for non-Aboriginal subjects). S. pneumoniae, followed by Haemophilus influenzae were the most common pathogens found. Both were sensitive to amoxycillin. The yield of definite pathogens was low. Staphylococcal and melioidosis pneumonia were confined to Aboriginal patients. Chlamydia, legionella and Mycoplasma pneumoniae were not identified.

The etiology and antimicrobial susceptibility patterns of microorganisms in acute community-acquired lung abscess

OBJECTIVE

To determine the spectrum and antibiotic susceptibility patterns of microorganisms causing acute community-acquired lung abscess.

DESIGN

A prospective survey.

SETTING

Medical emergency department and wards of a tertiary teaching hospital.

PATIENTS

Thirty-four adult patients with both clinical and radiologic features compatible with a diagnosis of acute community-acquired lung abscess who had received less than 48 h of antibiotic therapy.

INTERVENTIONS

Microbiologic specimens obtained by percutaneous lung aspiration and with a protected specimen brush via fiberoptic bronchoscopy were submitted for aerobic and anaerobic culture.

MAIN OUTCOME MEASURES

Identification of all microorganisms, including anaerobes, and determination of antibiotic susceptibility.

RESULTS

A mean of 2.3 bacterial species per patient was isolated, anaerobes alone being isolated in 44% of cases, aerobes alone in 19%, and mixed aerobic and anaerobic isolates in 22%. Aerobic Gram-negative pathogens were uncommon. In seven patients, Mycobacterium tuberculosis was identified; in two it was associated with other bacteria. In four patients, no organisms were isolated. All the nonmycobacterial isolates were susceptible to amoxicillin-clavulanate and in addition the anaerobes were all susceptible to chloramphenicol and almost all to a combination of penicillin and metronidazole. Among the anaerobes, the level of resistance to penicillin, metronidazole, and clindamycin individually was 21%, 12%, and 5%, respectively.

CONCLUSIONS

Community-acquired acute lung abscess is usually caused by multiple anaerobic and less frequently aerobic Gram-positive microorganisms, which should respond to empirical therapy with amoxicillin-clavulanate, chloramphenicol, or a combination of penicillin and metronidazole. Tuberculosis, which may be indistinguishable from an acute lung abscess, occurred in 21% of patients in our study. Most bacterial pathogens are sensitive to conventional antimicrobial therapy and further investigation with percutaneous lung aspiration or bronchoscopy is indicated only when there is lack of early response to therapy or there is the presence of atypical clinical features.

The effect of age on the presentation of patients with tuberculosis

OBJECTIVE

To study the differences in presentation of young and elderly patients with tuberculosis (TB).

DESIGN

Between January 1991 and December 1992 all patients with TB diagnosed at the Department of Medicine, Prince of Wales Hospital, were recruited into the study. The following data were collected: body weight, coexisting medical problems, presenting symptoms, radiographic appearance, sputum results for acid-fast bacilli and peripheral blood biochemistry. The patients were divided into young ( < 65 years) and elderly ( > or = 65 years) age groups and differences in presentation of the 2 groups were analysed.

RESULTS

There were 78 young and 94 elderly patients with TB. The elderly patients had lower body weight, less haemoptysis but more non-specific complaints (25% vs 1%, P = 0.001). The chest radiographs in the elderly patients were less likely to have upper lobe infiltration (9% vs 37%, P = 0.0002) but more commonly had extensive infiltration of both lungs (17% vs 2%, P = 0.014). The only biochemical abnormality that was more common in the elderly was a low serum albumin level (64% vs 45%, P < 0.05).

CONCLUSION

Elderly patients with TB are more likely to present with non-specific complaints and atypical radiographic appearance. A high index of suspicion and prompt investigations in elderly patients may allow for earlier diagnosis and treatment of TB.

The aetiology of severe community-acquired pneumonia and its impact on initial, empiric, antimicrobial chemotherapy

Of 259 patients admitted to an intensive care unit with severe acute community-acquired pneumonia, 173 had primary infections and 86 had secondary infections. The commonest organism isolated in each group was Streptococcus pneumoniae (51.3 and 36.6% of known isolates in each group respectively). Klebsiella pneumoniae was the next most common isolate (31.9 and 29.3% respectively). A variety of other Gram-negative organisms and Staphylococcus aureus accounted for most of the remaining pathogens. Based on retrospective analysis of data, there appeared to be no difference in the alcohol consumption of patients with infection due to S. pneumoniae and K. pneumoniae. The overall mortality rate for the primary infections was 47.4%, with 68.4% of these infections due to K. pneumoniae and 33.9% due to the pneumococcus (P < 0.002). Among the secondary infections, the overall mortality rate was 40.8% (not significantly different to that of primary infections) with 45.5% due to K. pneumoniae and 23.1% due to the pneumococcus (not significantly different on statistical analysis, probably due to low patient numbers). Our investigation confirms that severe community-acquired pneumonia due to K. pneumoniae is extremely common, even in patients without obvious risk factors for Gram-negative colonization. This organism is contributing to the high mortality rate seen in our intensive care unit among patients with pneumonia, and our empiric therapy for such cases routinely includes a combination of agents active against this organism (e.g. a cephalosporin and an aminoglycoside).

Overview of community-acquired pneumonia. Prognosis and clinical features

Despite the introduction of newer antibiotics, vaccinations, and better supportive care, CAP remains a common, frequently fatal disease. Age and coexisting illness influence which infectious agents are most likely to cause infection. Severity of illness and clinical features are influenced by various host factors and by the virulence of the infectious agent. Mortality and morbidity are reduced by the rapid institution of appropriate antimicrobial therapy. Because of the limitations of presently available diagnostic tests, many patients are begun on empiric regimens, and in up to half of these individuals, a cause is not identified. Although there are a number of potential pathogens, it is possible to identify likely pathogens based on easily identifiable clinical factors (age, presence of coexisting disease, severity of illness at presentation, and the need for hospitalization). Using this approach, CAP in immunocompetent adults may be divided into four categories. Once empiric therapy has been initiated, therapy should be continued for at least 72 hours unless clinical deterioration is noted. Within 4 days, fever and leukocytosis should return to baseline, but abnormal physical findings (i.e., crackles) require longer to resolve, especially with coexisting illness, and chest radiographic findings are the last to return to baseline and are especially delayed if the patient is bacteremic or has structural lung disease. Not all patients respond to initial empiric therapy. Reasons for this include antimicrobial resistance, the presence of nonbacterial pathogens (respiratory viruses), unusual bacterial pathogens, noninfectious causes that may mimic CAP, infectious complications (i.e., empyema), and pneumonia occurring in patients with unrecognized severe immunosuppression. Failure to improve after 72 hours and development of deterioration are indications for repeat diagnostic workup and consideration of alternative diagnoses. More invasive diagnostic tests are appropriate in severely ill patients and in those whose condition is deteriorating rapidly.