Cases Of Bacterial Pneumonia Research Articles

Bacterial Pneumonia among HIV-Infected Patients: Decreased Risk After Tobacco Smoking Cessation. ANRS CO3 Aquitaine Cohort, 2000–2007

BackgroundBacterial pneumonia is still a substantial cause of morbidity and mortality in HIV-infected patients in the era of combination Antiretroviral Therapy. The benefit of tobacco withdrawal on the risk of bacterial pneumonia has not been quantified in such populations, exposed to other important risk factors such as HIV-related immunodeficiency. Our objective was to estimate the effect of tobacco smoking withdrawal on the risk of bacterial pneumonia among HIV-infected individuals.Methodology/Principal FindingsPatients of the ANRS CO3 Aquitaine Cohort with ≥ two visits during 2000–2007 and without bacterial pneumonia at the first visit were included. Former smokers were patients who stopped smoking since ≥ one year. We used Cox proportional hazards models adjusted on CD4+ lymphocytes (CD4), gender, age, HIV transmission category, antiretroviral therapy, cotrimoxazole prophylaxis, statin treatment, viral load and previous AIDS diagnosis. 135 cases of bacterial pneumonia were reported in 3336 patients, yielding an incidence of 12 ‰ patient-years. The adjusted hazard of bacterial pneumonia was lower in former smokers (Hazard Ratio (HR): 0.48; P = 0.02) and never smokers (HR: 0.50; P = 0.01) compared to current smokers. It was higher in patients with <200 CD4 cells/µL and in those with 200 to 349 CD4 cells/µL (HR: 2.98 and 1.98, respectively; both P<0.01), but not in those with 350 to 499 CD4 cells/µL (HR: 0.93; P = 0.79), compared to those with ≥500 CD4 cells/µL. The interaction between CD4 cell count and tobacco smoking status was not statistically significant.Conclusions/SignificanceSmoking cessation dramatically reduces the risk of bacterial pneumonia, whatever the level of immunodeficiency. Smoking cessation interventions should become a key element of the clinical management of HIV-infected individuals.

Comparison of the clinical, microbiological, radiological and haematological features of foals with pneumonia caused by Rhodococcus equi and other bacteria

The purpose of this study was to compare the clinical, microbiological, radiological, haematological and cytological features of foals with pneumonia caused by Rhodococcus equi infection and with other bacteria, in order to provide markers for early diagnosis and treatment. A retrospective study of 113 cases of bacterial pneumonia was undertaken. Although there was considerable overlap in the affected populations, foals with R. equi pneumonia were significantly younger and had higher respiratory rates. Radiological evidence of thoracic abscessation had a sensitivity of 71% and a specificity of 85% for the diagnosis of R. equi pneumonia. Foals positive for R. equi also had higher peripheral white cell counts and fibrinogen concentrations than animals not infected with this pathogen. Respiratory rate, fibrinogen concentration and the log of the neutrophil count were retained in the final multivariate analysis. Using microbiological culture as the 'gold standard', identification of Gram-positive coccobacilli in tracheal aspirates was highly specific (91%), but poorly sensitive (35%) for R. equi infection. White cell counts >20,000cells/μL (86% specificity), fibrinogen concentrations >700mg/dL (92% specificity), radiological evidence of thoracic abscessation (85% specificity), and the presence of Gram-positive coccobacilli in tracheal aspirates (91% specificity) in pneumonic foals are highly suggestive of R. equi infection and justify early targeted antimicrobial intervention while awaiting culture results.

Late infectious complications after cord blood stem cell transplantation

The slower engraftment kinetics and impaired immune reconstitution of cord blood stem cell transplant recipients increase the risk of infectious complications. We retrospectively reviewed patients who underwent cord blood stem cell transplantation at Roswell Park Cancer Institute for hematological malignancies and who survived beyond day 100 for late infectious events. Among 15 patients who were included in the study, there were 18 episodes of bacteremia, 5 cases of bacterial pneumonia, 9 viral, 4 fungal, and 1 nontuberculous mycobacterial infection. Overall mortality was 60%, with infections contributing in 44% of cases. In conclusion, survival beyond day 100 following cord bloodstem cell transplantation is associated with a considerable risk of infections in our single center experience.

Epidemiology of new influenza A(H1N1) in the United Kingdom, April – May 2009

Following importations of cases from Mexico and the United States, by 11 May, United Kingdom surveillance activities had detected a total of 65 individuals with confirmed infections caused by the new influenza A(H1N1) virus. The infections were mainly in young people and younger adults and they spread within households and within schools. The illness in the United Kingdom is similar in severity to seasonal influenza and to date, besides one case of bacterial pneumonia, no clinically serious cases have occurred.

Viral RNA polymerase complex promotes optimal growth of 1918 virus in the lower respiratory tract of ferrets

The 1918 influenza pandemic was the most devastating outbreak of infectious disease in human history, accounting for about 50 million deaths worldwide. In addition to a significant number of cases of secondary bacterial pneumonia, this highly pathogenic strain of influenza A virus caused fatal primary viral pneumonia. To identify the viral gene(s) chiefly responsible for the high virulence of the 1918 virus, we generated a series of reassortants between the 1918 virus and a contemporary human H1N1 virus (A/Kawasaki/173/2001; K173) using reverse genetics. We then assessed their virulence properties in ferrets, a model closely resembling humans in terms of sensitivity to influenza virus infection and pattern of spread after intranasal inoculation. Substitution of single genes from the 1918 virus in the genetic background of K173 virus did not markedly alter the pattern of infection. That is, the reassortants grew well in nasal turbinates, but only sporadically (if at all) in the trachea and lungs. One exception was the 1918PB1/K173 reassortant, which replicated efficiently in lung tissues as well as the upper respiratory tract. A reassortant virus expressing the 1918 viral RNA polymerase complex (PA, PB1, and PB2) and nucleoprotein showed virulence properties in the upper and lower respiratory tracts of ferrets that closely resembled those of wild-type 1918 virus. Our findings strongly implicate the viral RNA polymerase complex as a major determinant of the pathogenicity of the 1918 pandemic virus. This new insight may aid in identifying virulence factors in future pandemic viruses that could be targeted with antiviral compounds.

Rituximab Increases Response to ESHAP in Relapsed, Refractory, and Transformed Aggressive B-Cell Lymphoma.

Background: Patients with relapsed or refractory aggressive B-cell lymphoma, or transformed indolent lymphoma can achieve long-term survival with high dose therapy and autologous stem cell transplant (HDT/ASCT), provided their disease is sensitive to salvage chemotherapy. Unfortunately, approximately 50% of patients are insensitive to standard salvage regimens.Objectives: This trial investigated whether adding Rituximab to ESHAP (etoposide, solumedrol, cytosine arabinoside, cisplatin) induction improved chemosensitivity. The primary outcome was overall response rate (CR + CRu + PR) to R-ESHAP. Secondary outcomes were toxicity, ability to undergo ASCT, progression free survival (PFS) and overall survival (OS).Methods: The protocol was approved by the local ethics review board and all patients provided informed consent. Eligible patients received ESHAP every 28 days with GCSF support until < 15% bone marrow involvement was achieved (2–4 cycles). Rituximab was given weekly x 8 weeks concurrent with the first 2 cycles of ESHAP. GCSF mobilized stems cells were collected on day 10–11 of cycle 1 or 2.Results: The trial was stopped early after the complete response (CR) rate at a planned interim analysis exceeded 40% (a pre-specified criteria for stopping the trial). Final results of 26 patients are presented. Median age was 55.5 years (range 42–64). Twelve patients had relapsed aggressive lymphoma, 2 had refractory disease and 12 had transformed indolent lymphoma. Twenty-two of 26 patients were stage III/IV. The overall response rate to R-ESHAP was 92% (95% CI 82% to 100%). Twelve patients (46%; 95% CI 27% to 65%) had a CR or unconfirmed CR. Grade 3–4 thrombocytopenia, neutropenia, and anemia occurred in 57%, 40%, and 15% of R-ESHAP cycles respectively. Grade 3–4 infections complicated 7% of cycles. Median follow-up was 17 months (range 2.9 to 43.2) from enrollment. Twenty-three of 26 patients (88%) were transplanted. Notable post-transplant toxicity included 5 cases of herpes zoster, 2 cases of bacterial pneumonia, 1 case of pulmonary aspergillosis, and 1 fatal case of pneumocystis carnii pneumonia (PCP). Three patients did not proceed to HDT/ASCT; 2 were refractory to R-ESHAP and 1 died of a myocardial infarction after induction chemotherapy but prior to ASCT. Fifteen of 23 patients who received ASCT remain in remission, 6 have relapsed. Seven patients have died, 4 of progressive disease, 1 of myocardial infarction, 1 of PCP, and 1 of accelerated Parkinson's Disease. Median PFS and median OS have not yet been reached.Conclusions: In this single-arm, phase II study of relapsed or refractory aggressive B-cell lymphoma and transformed indolent B-cell lymphoma, R-ESHAP induction therapy resulted in a very high ORR (92%) and enabled a large percentage of patients (88%) to proceed to HDT/ASCT. Toxicity of the R-ESHAP regimen was acceptable, and its efficacy compared favorably with other salvage regimens reported in the literature, including R-ICE.

Intradermal Immunization of Mice with Cholera Toxin B-Pneumococcal Surface Protein A Fusion Protein Is Protective against Intraperitoneal Challenge with Streptococcus pneumoniae

Cholera toxin B subunit is known for its adjuvant properties when associated with different antigens. In this work, we have fused the ctxB gene to the pneumococcal surface protein (pspA) gene from Streptococcus pneumoniae. Intradermal administration of the fusion protein in mice induced anti-PspA antibodies and protection against pneumococcus in a sepsis model. Streptococcus pneumoniae is the major cause of bacterial pneumonia, meningitis, and otitis media cases around the world, leading to up to 1 million deaths per year. Pneumococcal surface protein A (PspA) is a virulence factor partially conserved among the Streptococcus pneumoniae isolates that plays a role in complement inactivation during infection (18). Based on amino acid sequence diversity, PspAs can be classified into three families and six clades (8) that also display immunological cross-reactivity among themselves (17). In several pneumoccocal infection challenge models, PspA has proved to be a good vaccine candidate when administered either in protein-adjuvant formulations or in DNA-based vaccines (4, 11, 12). PspA was also shown to bind and to prevent the bactericidal activity of apolactoferrin (15), present in saliva and other mucosal secretions. In addition, anti-PspA antibodies were shown to enhance pneumococcal killing by lactoferrin, suggesting a mechanism for the reduction of pneumococcal carriage by these antibodies (15). In a recent work, we tested the immunogenic potential of a fusion protein composed of the cholera toxin B subunit (CTB) and pneumococcal surface antigen A from Streptococcus pneumoniae by intranasal inoculation of mice (3). In this work, we have amplified the 5′ terminus region (which encodes the α-helix region plus the proline-rich domain) of the pspA clade 3 gene from pTG-pspA′3 (11) (pspA′3 accession number, {type:entrez-nucleotide,attrs:{text:AY082389,term_id:22476378,term_text:AY082389}}AY082389), which carried the gene isolated from S. pneumoniae St 259/98 strain (Instituto Adolpho Lutz, Sao Paulo, SP, Brazil). The pspA′ gene was then cloned downstream of the ctxB gene in the pAE-CTB plasmid (2) in order to express a CTB-PspA′ fusion protein in Escherichia coli. Using this expression system, the recombinant protein contains an N-terminal six-His tag that allows purification through Ni2+ charged columns. This system was used for the expression and purification of the fusion protein CTB-PspA′ and CTB, as previously described (2, 3), and PspA′, with the observation that the last protein did not adsorb very well, and it was released from the column with 20 mmol · liter−1 imidazole.

Costos económicos de las neumonías en niños menores de 2 años de edad, en Colombia

To analyze the costs of pneumonias presumed to be of viral or bacterial origin, as diagnosed by chest X ray, in four reference center hospitals in three cities in Colombia. A total of 128 cases of pneumonia (64 bacterial cases and 64 viral cases) that had consecutively entered the hospitals in the study between July 2001 and January 2003 were investigated. The diagnosis of pneumonia was based on chest X rays. The study population was composed of children under 2 years of age who required hospitalization. In order to estimate the costs for bacterial pneumonias and viral pneumonias, the cost of each activity was determined for each case, and then average costs were calculated. The average cost of the presumably bacterial pneumonia cases was US $611.50 (95% confidence interval (95% CI), US $532.20-690.80); that of the presumably viral cases was US $472.20 (95% CI, US $331.80-612.60). The observed differences were due to direct expenses, especially drugs (antibiotics), special services, and diagnostic tests. In the two groups the families were similar in their incomes and the indirect costs that they had to bear, so the indirect costs were not considered relevant in terms of distinguishing between the costs caused by the two forms of pneumonia. The study found differences in the direct costs of care between the presumably bacterial cases and the presumably viral ones. The study results also gave an approximation of the indirect costs to the patients' families caused by the pneumonias. The differences found in the direct costs also indicate that X-ray diagnosis is useful for differentiating between viral and bacterial pneumonia. Few studies in Latin America have assessed the economic costs of pneumonia in children, so this study can serve as a reference for future research on the impact of interventions against pneumonia.

Is it possible to distinguish between atypical pneumonia and bacterial pneumonia?: evaluation of the guidelines for community-acquired pneumonia in Japan

The Japanese Respiratory Society (JRS) published the guidelines for the management of community-acquired pneumonia in 2000. The guidelines set up nine parameters and criteria for the differential diagnosis of atypical pneumonia and bacterial pneumonia based on clinical symptoms, physical signs and laboratory data. To evaluate the performance of these guideline criteria, 91 cases of Chlamydia pneumoniae (53 cases were pure-C. pneumoniae and 38 cases were mixed-C. pneumoniae pneumonia), 103 cases of Mycoplasma pneumoniae (86 cases were pure-M. pneumoniae and 17 cases were mixed-M. pneumoniae pneumonia) and 144 cases of bacterial (Streptococcus pneumoniae and/or Haemophilus influenzae) pneumonia were analyzed. The accordance rate for a suspected atypical pneumonia with the guideline criteria was 84.8% for pure-M. pneumoniae pneumonia and 60.3% for pure-C. pneumoniae pneumonia, but only 9.0% for bacterial pneumonia, 12.1% for mixed-C. pneumoniae pneumonia and 16.6% for mixed-M. pneumoniae pneumonia. Overall, the sensitivity and specificity of the criteria in the JRS guidelines were 75.5% and 90.9%, respectively. Our results indicated that the differentiation of pneumonia in the JRS guidelines is useful for the diagnosis of M. pneumoniae pneumonia, but difficult to apply to the diagnosis of C. pneumoniae pneumonia.

Observation and analysis of blood cells morphology of SARS patients

目的 观察分析传染性非典型肺炎(SARS)患者血细胞形态学变化.方法 220例临床确诊的SARS患者(包括死亡病例)、20例细菌性肺炎和20例病毒性肺炎患者外周血涂片,经瑞氏染色后,用普通光学显微镜观察其细胞形态.结果 SARS患者血细胞形态发生了明显的变化,其中167例患者中性粒细胞细胞核表面出现鼓槌样结构,156例的患者中性粒细胞质中非特异性颗粒粗大,121例的患者中性粒细胞出现空泡变性.其他肺炎患者血细胞未见上述形态学的改变.结论中性粒细胞核鼓槌样形成可能与SARS病程有关。

High correlation between the bacterial species in denture plaque and pharyngeal microflora.

The morbidity and mortality of the dependent elderly that result from aspiration pneumonia are recognized as a major geriatric health problem. Most cases of bacterial pneumonia are initiated following colonization or superinfection of the pharynx by pathogenic bacteria, followed by aspiration of pharyngeal contents. A recent study revealed that bacteria, that commonly cause respiratory infection, colonized the dentures of dependent elderly. This suggests that denture plaque may function as a reservoir of potential respiratory pathogens to facilitate colonization on the pharynx. The purpose of this study was to determine the possible correlation between denture and pharyngeal microflora. The denture and pharyngeal bacterial flora of 50 dependent elderly were examined, and the microorganisms identified by culturing. The agreement between the bacterial species in denture plaque and pharyngeal microflora was investigated using the Kappa method. The microorganism species on the dentures and pharyngeal mucosa of the subjects had an agreement rate of 68.5%. The agreement rate for each of the bacterial species of the dentures and pharynx was also demonstrated to be high. Dentures should be considered an important reservoir of organisations which could colonise the pharynx, and the importance of controlling denture plaque for the prevention of aspiration pneumonia cannot be overemphasized.

Quantitative Culture of Endotracheal Aspirates in the Diagnosis of Ventilator-Associated Pneumonia in Patients With Treatment Failure

To study the correlation of bacteriology between quantitative cultures of protected specimen brush (PSB), BAL, and quantitative endotracheal aspirate (QEA) in ventilator-associated pneumonia (VAP) patients with treatment failure. Prospective observational clinical study. A 15-bed medical ICU of tertiary medical center. Forty-eight patients receiving mechanical ventilation with clinical suspected VAP who had been treated with antibiotics for at least 72 h without improvement. QEA, PSB, and BAL were performed with patients receiving antibiotics. The diagnostic thresholds for QEA, PSB, and BAL were 10(5), 10(3), and 10(4) cfu/mL, respectively. Microbial culture findings were positive in 24 BAL samples (50%), in 23 PSB samples (48%), and in 28 QEA samples (58%). The correlations between of QEA vs PSB and QEA vs BAL were significant (rho = 0.567 and rho = 0.620, p < 0.01, respectively). The most commonly isolated microorganisms were Acinetobacter baumannii (27%), Staphylococcus aureus (24%), Stenotrophomonas maltophilia (15%), and Pseudomonas aeruginosa (10%). Using the predetermined criteria, bacterial pneumonia was diagnosed in 28 of 48 suspected VAP episodes based on PSB and/or BAL results. The diagnostic efficiency of QEA at threshold of 10(5) cfu/mL had a sensitivity of 92.8% and a specificity of 80%. QEA correlated with PSB and BAL in patients with suspected VAP who responded poorly to the existent antibiotic treatment. QEA missed only two cases of bacterial pneumonia diagnosed by invasive PSB and/or BAL with acceptable sensitivity and specificity. More importantly, QEA is noninvasive and easily repeatable. Early use of QEA is helpful to clinical physicians in decision making with regard to antibiotics use.

Comparative Study of KL-6, Surfactant Protein-A, Surfactant Protein-D, and Monocyte Chemoattractant Protein-1 as Serum Markers for Interstitial Lung Diseases

KL-6, surfactant protein (SP)-A, SP-D, and monocyte chemoattractant protein-1 (MCP-1) are reported to be sensitive markers for interstitial lung diseases (ILD). However, each marker has been studied independently. The aim of this study was a comparative analysis of the diagnostic values of these markers. Subjects consisted of 33 patients with ILD (21 cases of idiopathic pulmonary fibrosis and 12 associated with collagen vascular diseases) and 82 control subjects (12 cases of bacterial pneumonia and 70 healthy volunteers). Receiver operating characteristic curves revealed that KL-6 was superior to the other markers. The cut-off levels for these markers that resulted in the highest diagnostic accuracy were determined to be 465 U/ml for KL-6, 48.2 ng/ml for SP-A, 116 ng/ml for SP-D, and 1080 pg/ml for MCP-1. The sensitivity, specificity, and diagnostic accuracy were 93.9%, 96.3%, and 95.7% for KL-6; 81.8%, 86.6%, and 85.2% for SP-A; 69.7%, 95.1%, and 87.8% for SP-D; and 51.5%, 92.7%, and 80.9% for MCP-1; respectively. The serum levels of SP-A and SP-D, but not of KL-6, were significantly higher in patients with bacterial pneumonia than in healthy volunteers. These results suggest that of the markers studied, KL-6 is the best serum marker for ILD.

Bilan médical d’une unité d’hospitalisation ouverte pendant l’épidémie de grippe de l’hiver 1999–2000

Purpose. – Last winter, a great many patients with influenza-like infection were admitted to our hospital, leading us to open a specific unit for 6 weeks. We report the evaluation of medical care given to these patients. Methods. – Useful data for evaluating care to patients presenting respiratory infections were determined beforehand by the retrospective analysis of patients’ charts. Results. – Fifty-seven out of 185 admitted patients (31%) had infectious respiratory symptoms. The mean age was 81 years. Six cases of influenza virus infection, 43 cases of viral bronchitis, six cases of bacterial pneumonia, one superinfected asthma and one septic shock were diagnosed. All patients presented with cardiac and/or chronic pulmonary diseases. Influenza vaccination had been performed in 28 patients (49%). Before hospitalisation, 30 patients (52%) had received antibiotics, and 17 (30%) a steroid therapy. In contrast, only 12 patients (21%) have received anti-infective agents during the hospitalisation. Twenty-five patients were able to go back home and a nursing home was required for 27 patients (47%); five patients died. Tools for improving this specific department in a public hospital are discussed. Conclusion. – Vaccinations in the elderly appear to be poorly utilized; meanwhile, antibiotic treatments, as well as steroid therapy, are overused. Managing epidemic infections requires attention from the public hospital system.

Complicaciones respiratorias en el trasplante de progenitores hematopoyéticos. ¿Qué aporta la radiología?

To determine the incidence of respiratory complications and their manifestations in both conventional radiology and high-resolution computerized tomography (HRCT) in a series of patients who had undergone blood progenitor cell transplantation (BPCT). The objective was to evaluate whether the radiological findings associated with post-transplantation time can be useful for establishing the differential diagnosis. A study was undertaken of a total of 108 consecutive patients who had undergone BPCT and were alive one year after; from these patients a selection was made of those who had some respiratory complications during the first year after transplantation. Complications were classified in three different groups on the basis of time elapsed since transplantation (early, intermediate, and late stages). Chest X-ray films of each patient were examined and in 17 cases the study was completed with HRCT. These findings were correlated with both definitive diagnosis and time elapsed since BPCT. The following procedures were useful for diagnostic confirmation: blood culture, sputum culture, fibrobronchoscopy with bronchoalveolar lavage or lung biopsy, biopsy by other methods, necropsy, or clinical course after empirical therapy. Thirty-three out of the 108 patients undergoing BPCT had some form of respiratory complication during the first year after transplantation. The most common radiological pattern both in the chest X-ray and in HRCT was alveolar consolidation. Other findings included ground-glass appearance, interstitial pattern, pulmonary nodules, and pleural effusion. The diagnoses in relation to the different stages of transplantation were: a) early stage: three cases of heart failure, two cases of alveolar hemorrhage, two cases of pulmonary aspergillosis and three cases of undocumented complications; b) intermediate stage: four cases of cytomegalovirus pneumonia, one case of pulmonary aspergillosis, two cases of bacterial pneumonia, and two cases of undocumented pneumonitis; c) late stage: four cases of bacteriologically documented pneumonia, two cases of pneumonitis with an unidentified agent, two cases of graft-versus-host disease, one case of pulmonary aspergillosis and two complications without established diagnosis. The relationship between radiological findings and time elapsed since transplantation of blood precursor cells is very useful for establishing the diagnosis of pulmonary complications. High resolution computerized tomography is useful for detecting unnoticed lesions in conventional X-ray, and for diagnosing bronchiolitis obliterans and some fungal lesions.

Acute parenchymal lung disease in immunocompetent patients: diagnostic accuracy of high-resolution CT.

The purpose of this study was to determine whether acute parenchymal lung diseases can be differentiated on the basis of the pattern and distribution of abnormalities revealed on high-resolution CT. High-resolution CT scans of 90 patients with acute parenchymal lung diseases (19 with bacterial pneumonia, 13 with mycoplasmal pneumonia, 21 with acute interstitial pneumonia, 18 with hypersensitivity pneumonitis, 10 with acute eosinophilic pneumonia, and nine with pulmonary hemorrhage) were independently assessed by two observers who had no knowledge of clinical or pathologic data. The observers recorded abnormalities, their first-choice diagnosis, and their degree of confidence in their first-choice diagnosis. The two observers made a correct first-choice diagnosis in an average of 55 (61%) of 90 cases. Correct first-choice diagnosis was made in 50% of cases of bacterial pneumonia, 62% of mycoplasmal pneumonia, 90% of acute interstitial pneumonia, 72% of hypersensitivity pneumonitis, 30% of acute eosinophilic pneumonia, and 28% of pulmonary hemorrhage. CT findings allowed distinction between infectious and noninfectious causes in 81 (90%) of 90 cases. High-resolution CT is helpful in the differential diagnosis of infectious from noninfectious acute parenchymal lung disease. However, high-resolution CT is of limited value in making a specific diagnosis.

Bacterial pneumonia in children

Pneumonia is the leading cause of death in children around the world. This article reviews the clinical manifestations, diagnoses, and management of the major causes of bacterial pneumonia in children of different ages. Major pathogens causing pneumonia in newborns include group B streptococcus, Listeria monocytogenes , and Chlamydia trachomatis , organisms that can infect infants born to mothers who have genital tract colonization. Streptococcus pneumoniae remains the most common cause of serious bacterial pneumonia in children, and the increasing incidence of penicillin-resistant strains can complicate therapy. Mycoplasma pneumoniae and Chlamydia pneumoniae are the most common causes of pneumonia in school-aged children. In most cases of bacterial pneumonia, a specific cause is not determined, and empiric therapy is based on the likely pathogens as determined by the child's age and the clinical presentation. Prevention, through simple measures such as breast-feeding and avoidance of exposure to passive smoke, as well as widespread use of available vaccines, is the most effective means of reducing the morbidity and mortality associated with bacterial pneumonia.

Respiratory infections in patients with HIV infection.

Changes in epidemiology have influenced the spectrum of pulmonary diseases in HIV-infected populations. The increasing proportion of patients with AIDS who are intravenous drug users and members of racial or ethnic minorities correlate with increasing cases of bacterial pneumonia and tuberculosis. Both of these infections also occur more frequently with advanced immunosuppression. Antipneumocystis prophylaxis is also reducing the incidence and mortality rate from this infection, but when respiratory failure occurs with Pneumocystis carinii pneumonia, the mortality rate is high. Immunosuppression due to HIV causes active tuberculosis in many, and tuberculosis appears to accelerate the course of HIV disease. Directly observed therapy of tuberculosis has made a major impact on the incidence and cure rates of tuberculosis in areas of high prevalence. Pulmonary disease has been a major cause of illness and death in patients with HIV infection since the beginning of the AIDS epidemic. Early in the epidemic, P. carinii pneumonia was considered the predominant pulmonary disorder. However, epidemiologic shifts and advances in treatment have broadened our perspective on the diseases that patients with HIV infection develop.

Diagnostic Value of Protected BAL in Diagnosing Pulmonary Infections in Immunocompromised Patients

To assess the diagnostic utility of protected BAL (P-BAL) in respiratory infections in immunocompromised patients and to examine whether P-BAL alone could substitute the combined use of protected specimen brush (PSB) and BAL in such patients. Thirty-seven immunocompromised patients who underwent PSB, P-BAL, and BAL simultaneously for the diagnosis or exclusion of bacterial or nonbacterial opportunistic respiratory infections were studied prospectively. The P-BAL was performed through the inner catheter of a telescoping plugged catheter with 60 mL of saline solution. Thirteen (35%) cases of bacterial pneumonia were diagnosed. PSB obtained seven true-positive (TP) results, P-BAL obtained nine, and BAL obtained eight TP. Results of the three techniques were positive and concordant in 6 of the 13 cases. PSB remained free of contamination from oropharyngeal flora in all cases, P-BAL was contaminated twice, and BAL was contaminated in four cases. Opportunistic respiratory infections were diagnosed in 19 patients. P-BAL results were identical to those with BAL in all cases: 18 TP and 1 false-negative. The average volume of P-BAL fluid retrieved was 19 mL, sufficient for all microbiologic and cytologic processings. P-BAL was more time-consuming than both PSB and BAL procedures and was technically more complex. P-BAL alone can substitute the combined use of both PSB and BAL in immunocompromised patients and attains a higher sensitivity than PSB in diagnosing bacterial pneumonia. The combined strategy continues to be a good choice, but due to the high incidence of bacterial pneumonia in these patients, a highly efficient diagnostic procedure is required not only for nonbacterial opportunistic respiratory infections but also for bacterial pneumonia.

Bacterial pneumonia in recipients of bone marrow transplantation. A five-year prospective study.

Bacterial pneumonia as an important complication of bone marrow transplantation (BMT) has not been subjected to comprehensive analysis. Two hundred fifty-five consecutive allogeneic and autologous BMT recipients, ranging in age from 1 month to 53 years, were prospectively followed for 3 days to 3 years (median, 108 days) for development of bacterial pneumonia. Etiology, place acquired, chest radiography, and outcome were recorded and the association between bacterial pneumonia and demographic and clinical variables was analyzed. Thirty-seven (15%) patients experienced 52 episodes of bacterial pneumonia: onset of 13 episodes occurred within 30 days after transplantation, 10 episodes occurred on days +31 to +100, and 29 episodes occurred thereafter. Bacterial pneumonia was the terminal event or contributed to fatal outcome in 8 patients (22% of bacterial pneumonia cases, 3% total study population). Mortality due to hospital-acquired pneumonia (6/21) was significantly higher than (P = 0.03). Bacterial pathogens were identified in 27 (52%) episodes. During the first 100 days after BMT, hospital-acquired Gram-negative bacteria predominated, caused mainly by Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter lwoffi, and Enterobacter cloacae. After day +100, community-acquired, Gram-positive bacteria predominated, particularly Streptococcus pneumoniae. Haemophilus influenzae occurred periodically. Considering all episodes, significant association was found between bacterial pneumonia and veno-occlusive disease (VOD) (P < 0.01) and chronic graft-versus-host disease (GVHD) (P < 0.02). For culture-positive episodes, the association between bacterial pneumonia and VOD was significant (P < 0.001) and borderline for acute GVHD (P = 0.07). It is concluded that VOD and GVHD are positively associated with post-BMT bacterial pneumonia. Its incidence, etiology, risk factors, and outcome are important considerations in its prevention and treatment.