Different Types Of Pneumonia Research Articles

The pulmonary virome, bacteriological and histopathological findings in bovine respiratory disease from western Canada.

The aetiology and pathogenesis of bovine respiratory disease (BRD) are complex and involve the interplay of infectious agents, management and environmental factors. Previous studies of BRD focused on ante‐mortem samples from the upper respiratory tract and identified several unconventional viruses. The lung, however, is the primary location where significant BRD lesions are usually found and is a common post‐mortem diagnostic specimen. In this study, results of high‐throughput virome sequencing, bacterial culture, targeted real‐time PCR and histological examination of 130 bovine pneumonic lungs from western Canadian cattle were combined to explore associations of microorganisms with different types of pneumonia. Fibrinous bronchopneumonia (FBP) was the predominant type of pneumonia (46.2%, 60/130) and was associated with the detection of Mannheimia haemolytica. Detection of Histophilus somni and Pasteurella multocida was associated with suppurative bronchopneumonia (SBP) and concurrent bronchopneumonia and bronchointerstitial pneumonia (BP&BIP), respectively. Sixteen viruses were identified, of which bovine parvovirus 2 (BPV2) was the most prevalent (11.5%, 15/130) followed by ungulate tetraparvovirus 1 (UTPV1, 8.5%, 11/130) and bovine respiratory syncytial virus (BRSV, 8.5%, 11/130). None of these viruses, however, were significantly associated with a particular type of pneumonia. Unconventional viruses such as influenza D virus (IDV) and bovine rhinitis B virus (BRBV) were detected, although sparsely, consistent with our previous findings in upper respiratory tract samples. Taken together, our results show that while virus detection in post‐mortem lung samples is of relatively little diagnostic value, the strong associations of H. somni and M. haemolytica with SBP and FBP, respectively, indicate that histopathology can be useful in differentiating bacterial aetiologies.

Lung Microbiota and Pulmonary Inflammatory Cytokines Expression Vary in Children With Tracheomalacia and Adenoviral or Mycoplasma pneumoniae Pneumonia.

Community-acquired pneumonia (CAP) is a worldwide infectious disease caused by bacteria, viruses, or a combination of these infectious agents. Mycoplasma pneumoniae is an atypical pneumonia pathogen that causes high morbidity and mortality in children, and adenovirus can lead to severe pneumonia. However, the etiology of different types of pneumonia is still unclear. In this study, we selected a total of 52 inpatients with M. pneumoniae pneumonia (MPP) (n = 21), adenovirus pneumonia (AVP) (n = 16), or tracheomalacia (n = 15) to serve as a disease control. Bronchoalveolar lavage fluid (BALF) samples that had been obtained for clinical use were analyzed. We compared the differences in microbiota and the expression of 10 inflammatory cytokines in samples between MPP, AVP, and tracheomalacia. We found that the bacterial diversity in MPP was lower than that in AVP and tracheomalacia. Mycoplasma, Streptococcus, and Pseudomonas were predominant in samples of MPP, AVP, and tracheomalacia, respectively. The expression levels of IL-6, IL-8, and IL-10 were significantly higher in inpatients with AVP compared to children hospitalized with tracheomalacia or MPP. The lung microbiota in MPP was remarkably correlated with IL-2, IL-4, IL-5, IL-6, TNF-α, and IL-1α expressions, while this was not found in tracheomalacia and AVP. Microbiota analysis identified a high load of multi-drug resistant Acinetobacter baumannii in the lung microbiota of several inpatients, which might be associated with the long hospitalization length and intra-group differences at the individual level. This study will help to understand the microbial etiology of tracheomalacia, AVP, and MPP and to identify effective therapies for these diseases.

Morphological peculiarities of pneumonia in the use of antibiotics and antioxidants

The study of pneumonia and its treatment have been going on for decades, but complex therapy is still not effective enough, which makes it relevant in our time. The purpose of the work is to reveal the morphogenesis of pneumonia in conditions of application of antioxidants. In this work a comparative description of the results of lung necropolis and analyzes of patients' protocols in the treatment of antibiotics with antioxidants and without their using was made, morphological features were compared with different types of pneumonia. Data were obtained from the Vinnytsia Oblast Department of Pathology and Anatomy (OSPAB). 16 patients were divided into 4 groups of 4 people in each (A - died of lobar pneumonia, B - died of gangrenous pneumonia, B - died of segmental pneumonia, G - died of focal pneumonia). Patients are divided into 2 subgroups, depending on the method of treatment (I subgroup - therapy with antibiotics and antioxidants, II subgroup - antibiotics without the use of antioxidants). This allowed us to detect the direct role of antioxidants in the treatment of various types of pneumonia. When we compared morphological differences, depending on the type of treatment, a number of criteria were taken into account, namely: the degree of filling of the alveoli with air, the number of erythrocytes, leukocytes and neutrophils in the field of view. As a result, we have found indisputable evidence that antioxidants are an important element in the treatment of pneumonia. Based on the research, it was found that antioxidant therapy positively affects the course of pneumonia. The histological picture of cranial, gangrenous and segmental pneumonia is characterized by a decrease in segmental neutrophils in the alveoli, and with focal pneumonia in bronchioles. With clover and gangrenous pneumonia, an increase in air in the alveoli and moderate hypertrophy in the vasculature was observed. Morphological changes in pulmonary tissue with the use of antioxidants were to reduce the number of neutrophils and erythrocytes in the exsudate, the presence of small amounts of air in the alveoli, whereas in the other therapy, the alveoli were irritable. Flexibility of interalveolar membranes in the application of antioxidant therapy was more moderate than without its application.

A Comparative Cost Analysis of Antibiotic Treatment for Community Acquired Pneumonia (CAP) in Adult Inpatients at Piggs Peak Government Hospital in Swaziland

Background: Of the different types of pneumonia, community acquired pneumonia (CAP), has been identified as the leading cause of infectious morbidity and mortality in the western and developing countries. To eradicate the bacterial cause of CAP, medical doctors) often tend to prescribe a differing cocktail of medicine which may be costly for the health care system.Aim: To analyze the cost of oral and/or intravenous antibiotic medicine use in different treatment approaches for treating CAP in adult inpatients from the health care system perspective.Settings: This study was undertaken at Piggs Peak Government Hospital, a 220 bed tertiary hospital located in the rural northern Hhohho region of Swaziland.Method: Seventy-one (n = 71) medical records of adult patients, hospitalized and diagnosed with CAP at Piggs Peak Government Hospital from July 2014 to June 2015, were retrieved and entered into the database once confirmed as having met the selection criteria. Only direct antibiotic medicine(s) costs were considered. The total cost per treatment option was calculated by multipling the unit cost of the medicine by the administration frequency and the length of hospital stay. The Kruskal-Wallis test was used to compare the cost difference between more than two treatment options.Results: Medical doctors at Piggs Peak Government Hosptial use a range of antibiotics to treat community acquire pneumonia. Furthermore, doctors prefer using dual antibiotics combination as first line treatment of CAP in adult inpatients. The cost of treating community acquire pneumonia at the hospital ranged from ZAR 70.98 to ZAR 467.60 per adult inpatient admitted into care. A statistically significant difference in the cost of the different treatment approaches used for treating CAP was noted.Conclusion: This cost-exploratory study has highlighted a significant difference in the monetary cost of the differing approaches used for treating CAP at the hospital. It is evident therefore that the use of different treatment approaches in treating CAP significantly influences the cost of CAP treatment. There is therefore need for cost minimization measure to be put in place at the facility.

Aspiration and Non-Aspiration Pneumonia in Hospitalized Children With Neurologic Impairment.

Children with neurologic impairment (NI) are commonly hospitalized for different types of pneumonia, including aspiration pneumonia. We sought to compare hospital management and outcomes of children with NI diagnosed with aspiration versus nonaspiration pneumonia. A retrospective study of 27 455 hospitalized children aged 1 to 18 years with NI diagnosed with pneumonia from 2007 to 2012 at 40 children's hospitals in the Pediatric Health Information System database. The primary exposure was pneumonia type, classified as aspiration or nonaspiration. Outcomes were complications (eg, acute respiratory failure) and hospital utilization (eg, length of stay, 30-day readmission). Multivariable regression was used to assess the association between pneumonia type and outcomes, adjusting for NI type, comorbid conditions, and other characteristics. In multivariable analysis, the 9.7% of children diagnosed with aspiration pneumonia experienced more complications than children with nonaspiration pneumonia (34.0% vs 15.2%, adjusted odds ratio [aOR] 1.2 (95% confidence interval [CI] 1.1-1.3). Children with aspiration pneumonia had significantly longer length of stay (median 5 vs 3 days; ratio of means 1.2; 95% CI 1.2-1.3); more ICU transfers (4.3% vs 1.5%; aOR 1.4; 95% CI 1.1-1.9); greater hospitalization costs (median $11 594 vs $5162; ratio of means 1.2; 95% CI 1.2-1.3); and more 30-day readmissions (17.4% vs 6.8%; aOR 1.3; 95% CI 1.2-1.5). Hospitalized children with NI diagnosed with aspiration pneumonia have more complications and use more hospital resources than when diagnosed with nonaspiration pneumonia. Additional investigation is needed to understand the reasons for these differences.

Adherence to antibiotic treatment guidelines and outcomes in the hospitalized elderly with different types of pneumonia

BackgroundFew studies evaluated the clinical outcomes of Community Acquired Pneumonia (CAP), Hospital-Acquired Pneumonia (HAP) and Health Care-Associated Pneumonia (HCAP) in relation to the adherence of antibiotic treatment to the guidelines of the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) in hospitalized elderly people (65years or older). MethodsData were obtained from REPOSI, a prospective registry held in 87 Italian internal medicine and geriatric wards. Patients with a diagnosis of pneumonia (ICD-9 480-487) or prescribed with an antibiotic for pneumonia as indication were selected. The empirical antibiotic regimen was defined to be adherent to guidelines if concordant with the treatment regimens recommended by IDSA/ATS for CAP, HAP, and HCAP. Outcomes were assessed by logistic regression models. ResultsA diagnosis of pneumonia was made in 317 patients. Only 38.8% of them received an empirical antibiotic regimen that was adherent to guidelines. However, no significant association was found between adherence to guidelines and outcomes. Having HAP, older age, and higher CIRS severity index were the main factors associated with in-hospital mortality. ConclusionsThe adherence to antibiotic treatment guidelines was poor, particularly for HAP and HCAP, suggesting the need for more adherence to the optimal management of antibiotics in the elderly with pneumonia.

Subclinical pulmonary pathogenic infection in camels slaughtered in Cairo, Egypt.

Camels migrate between the open boundaries of Sudan and Egypt either for grazing or for slaughtering. Bad hygiene and stress is often related to pulmonary diseases in camels. This study investigated whether camels slaughtered in Cairo carried pulmonary infections. Five hundred lung tissues of slaughtered camels were examined and 100 samples suspected for pulmonary infection were subjected to microbial identification and histopathology. A total of 70 lung tissues revealed 97 bacterial isolates of 8 species, including Staphylococcus aureus (37.14%), Escherichia coli (27.14%), Klebsiella pneumoniae (26.71%), Bacillus spp. (25.72%), Streptococcus pyogenes (10%), Corynebacterium spp. (8.85 %), Pasteurella spp. (2.85%), and Arcanobacterium pyogenes (1.4%). Some of these species were earlier reported to be associated with pulmonary infection. Histopathology revealed different types of pneumonia in 50% of the investigated lungs. A considerable number of apparently healthy camels carry pathogenic agents in their lower respiratory tracts. Immunosuppression and stressful conditions might influence these pathogens to induce respiratory diseases in camels. Thus, the infected camels might act as reservoir of these infections agents. If adequate care is not taken, this might be a threat to abattoir workers and may spread infections to humans.

The (H1N1) 2009 Pandemic Influenza Pneumonia among Adult Patients in Japan

The recent H1N1 influenza pandemic involved several cases of influenza pneumonia. Although influenza pneumonia may have occurred more frequently in fatal cases, the clinical characteristics of influenza pneumonia in Japan remain unclear. We conducted a retrospective cohort study of adult patients with influenza pneumonia, for which questionnaires were sent to respiratory physicians working in 2,491 hospitals across Japan. Questionnaires were returned by 994 physicians (39.9%), providing data on 346 influenza pneumonia cases. The case-fatality ratio was 8.2% (27 cases). Pure influenza viral pneumonia was observed in 94 cases, which were most frequently young adults with chief complaints of non-productive cough and dyspnea. Radiological imaging showed diffuse ground-glass opacity. Corticosteroid therapy and mechanical ventilation were more frequently used for pure influenza viral pneumonia, but these modalities were not correlated with poor treatment outcomes. Anti-influenza antiviral drugs were prescribed in 335 cases (96.8%). In the recent pandemic in Japan, several pure influenza viral pneumonia cases were observed, but we found no variances in mortality between the different types of pneumonia. Almost all cases were treated with anti-influenza antiviral drugs, which may have contributed to its relatively low mortality rate.

Morphological and immunohistochemical features of the lung tissue in Sudden Infant Death Syndrome (SIDS)

Morphological and immunohistochemical features of the lung tissue from 50 corpses of infants aged 1 month to 1 year were studied to determine their place in the structure of causes of death. Immunohistochemistry revealed decreased expression of surfactant protein B in most cases of sudden infant death syndrome (SIDS), which is probably due to qualitative changes in pulmonary surfactant. The data obtaine d suggest that the comprehensive studies of lung tissue of infants may contribute to clarifying the degree of risk and more accurately determining the causes of death in some cases of sudden infant death. This will help reduce the risk of diagnostic errors, i.e., hypo- or overdiagnosis SIDS and is of practical importance for forensic examination. This is especially true for those cases that require the need for differential diagnosis of SIDS with different types of pneumonia or mechanical asphyxia. Further investigations in this area should focus on the study of the molecular and genetic mechanisms of synthesis and transport of surfactant proteins, and to develop simple inexpensive methods for detection of the lungs surfactant deficiency in infants.

E04 Causes of death in Huntington's disease

BackgroundHuntington's disease (HD) is a progressive neurodegenerative autosomal dominant disease characterised by choreatic and hypokinetic movements, disturbed behaviour and cognitive decline. Previous studies into the cause of death in HD...

The final gasp from the European experts

Dear Editor: We read with interest the special article ‘Defining, treating and preventing hospital acquired pneumonia: European perspective’ by Dr. Torres et al. [1]. We were particularly interested in two topics chosen by the European experts: definitions and prevention. With regard to definitions, we fully agree with the experts that the term ventilator-associated pneumonia [VAP] is not appropriate and should be abandoned. The European experts suggest the terms intubation-associated pneumonia (IAP) be used for early onset pneumonia and tubeassociated pneumonia (TAP) for late onset pneumonia. However, we would like to suggest that these terms do not define the problem adequately. We would argue that the severity of underlying disease is the major determinant of developing pneumonia on intensive care [2, 3], and, therefore, the term critical illness related pneumonia [CIRP] would be more descriptive. The European experts also state that the preventive approach using selective decontamination of the digestive tract [SDD] plus short-term systemic intravenous antimicrobial treatment should not be called SDD. As two of the originators of SDD, we would humbly suggest that this is a little presumptuous and demonstrates a lack of insight into the philosophy of SDD. The SDD philosophy is based on the carrier state concept [4], which distinguishes among three different types of pneumonia (primary endogenous, secondary endogenous and exogenous) due to a limited range of potentially pathogenic microorganisms (six ‘normal’ and nine ‘abnormal’). Each of the three types of pneumonia requires different prophylactic interventions. Parenteral antimicrobial agents control primary endogenous pneumonia, enteral antimicrobial agents prevent secondary endogenous pneumonia, and a high level of hygiene combined with topical antimicrobials can control exogenous pneumonia. SDD using hygiene, topical, parenteral and enteral antimicrobial agents is a prophylactic protocol that aims at the control of exogenous, primary endogenous, and secondary endogenous pneumonias resulting in a proven reduction in mortality. With regard to prevention of IAP or TAP, Table 4 in the article outlines a series of recommended measures for their prevention. However, as far as we are aware none of the generally recommended measures are associated with evidenced based survival benefit. Amongst the additional measures, only one, SDD demonstrates unequivocal evidence based survival benefit [5]. In conclusion, this European exercise while well intentioned is not comprehensive and misses essential issues, notably evidence based practice.

Symptomatic dysferlin gene mutation carriers: Characterization of two cases

To describe two symptomatic dysferlin gene mutation carriers. One patient had limb girdle weakness. His brother was diagnosed with limb girdle muscular dystrophy 2B with two mutations in the dysferlin gene (D625Y and E1734G). The second patient had distal weakness. He had two sons with Miyoshi myopathy with a homozygous mutation (G519R). We performed immunofluorescence (dystrophin, DAG proteins, dysferlin, caveolin-3), Western blot (dysferlin, caveolin-3, calpain-3), and real-time PCR (dysferlin) using skeletal muscle samples. We also studied dysferlin in peripheral blood monocytes (PBMs) by Western blot. In addition to the muscle weakness, both patients showed elevated creatine kinase and abnormal muscle MRI. They presented a mutation in only one allele after screening of the whole gene (skeletal muscle and monocyte mRNA and genomic DNA). A muscle biopsy specimen showed moderate dystrophic changes and patchy dysferlin expression in the sarcolemma. Western blot of both PBMs and skeletal muscle demonstrated a significant reduction in dysferlin. All the other proteins including caveolin-3 and calpain-3 were normal. Real-time PCR showed normal levels of dysferlin mRNA vs the patients' affected relatives. The diagnosis of symptomatic carriers of dysferlin mutations should be considered when a pathologic pattern of dysferlin protein is observed.

Diseases and causes of mortality among sea turtles stranded in the Canary Islands, Spain (1998-2001)

This paper lists the pathological findings and causes of mortality of 93 sea turtles (88 Caretta caretta, 3 Chelonia mydas, and 2 Dermochelys coriacea) stranded on the coasts of the Canary Islands between January 1998 and December 2001. Of these, 25 (26.88%) had died of spontaneous diseases including different types of pneumonia, hepatitis, meningitis, septicemic processes and neoplasm. However, 65 turtles (69.89%) had died from lesions associated with human activities such as boat-strike injuries (23.66%), entanglement in derelict fishing nets (24.73%), ingestion of hooks and monofilament lines (19.35%), and crude oil ingestion (2.15%). Traumatic ulcerative skin lesions were the most common gross lesions, occurring in 39.78% of turtles examined, and being associated with Aeromonas hydrophila, Vibrio alginolyticus and Staphylococcus spp. infections. Pulmonary edema (15.05%), granulomatous pneumonia (12.90%) and exudative bronchopneumonia (7.53%) were the most frequently detected respiratory lesions. Different histological types of nephritis included chronic interstitial nephritis, granulomatous nephritis and perinephric abscesses, affecting 13 turtles (13.98%). Ulcerative and fibrinous esophagitis and traumatic esophageal perforation were the most frequently observed lesions in the esophagus, being associated in the majority of the cases with ingestion of fishing hooks. Larval nematodes of the Anisakidae family caused gastritis in 15 turtles (16.13%). Necrotizing and/or granulomatous hepatitis were the lesions most commonly observed in the liver (27.95%). Traumatic lesions included necrotizing myositis (10.75%) mainly caused by entanglement in fishing nets or boat-strikes, and amputation of 1 or 2 flippers (25.81%) by netting. Traumatic erosions and/or fractures of the carapace/plastron mainly caused by boat-strikes were also observed (26.88%). Eye lesions included heterophilic keratoconjunctivitis, ulcerative keratitis and heterophilic scleritis, affecting 7 turtles (7.53%).

Pneumonia: high-resolution CT findings in 114 patients.

The objective of the present study was to assess the high-resolution CT appearances of different types of pneumonia. The high-resolution CT scans obtained in 114 patients (58 immunocompetent, 59 immunocompromised) with bacterial, Mycoplasma pneumoniae, viral, fungal, and Pneumocystis carinii pneumonias were analyzed retrospectively by two independent observers for presence, pattern, and distribution of abnormalities. Areas of air-space consolidation were not detected in patients with viral pneumonia and were less frequently seen in patients with Pneumocystis carinii pneumonia (2 of 22 patients, 9%) than in bacterial (30 of 35, 85%), Mycoplasma pneumoniae (22 of 28, 79%), and fungal pneumonias (15 of 20, 75%; p<0.01). There was no significant difference in the prevalence or distribution of consolidation between bacterial, Mycoplasma pneumoniae, and fungal pneumonias. Extensive symmetric bilateral areas of ground-glass attenuation were present in 21 of 22 (95%) patients with Pneumocystis carinii pneumonia and were not seen in other pneumonias except in association with areas of consolidation and nodules. Centrilobular nodules were present less commonly in bacterial pneumonia (6 of 35 patients, 17%) than in Mycoplasma pneumoniae (24 of 28, 96%), viral (7 of 9, 78%), or fungal (12 of 20, 92%) pneumonia ( p<0.01). Except for Pneumocystis carinii pneumonia and Mycoplasma pneumoniae pneumonia, which often have a characteristic appearance, high-resolution CT is of limited value in the differential diagnosis of the various types of infective pneumonia.

Clinical aspects of pneumonia

Pneumonia is a serious medical condition and a major cause of morbidity and mortality worldwide. It has many infectious aetiologies, although bacterial and viral forms are most common. Our understanding of pneumonia has improved significantly during the course of the 20th century but the overall disease burden has changed little. Although antibiotics have helped to reduce the mortality associated with some types of pneumonia, the level of morbidity remains constant. Furthermore, the existence of antibiotic-resistant bacteria worldwide is becoming an increasing problem in treatment. This essay describes the different types of pneumonia from a clinical perspective and highlights the problems associated with the condition.

Etiology and Diagnosis of Pneumonia Requiring ICU Admission

The spectrum of pathogens and the microbiologic investigations used to obtain a diagnosis in 178 patients with severe pneumonia (88 percent requiring intermittent positive-pressure ventilation) are reviewed. Ninety-five patients had primary pneumonia, 31 had nosocomial pneumonia, 24 were immunocompromised patients, and 28 had aspiration pneumonia. While the spectrum of isolates conformed to the usual patterns for the different types of pneumonia, the incidence of Gram-positive infections (15 percent), predominantly Klebsiella pneumoniae, Staphylococcus aureus, (8 percent), and Legionella pneumophila (5 percent) in primary pneumonia was much higher than in community or general hospital-based studies, and only one case of Mycoplasma pneumoniae was identified. Gram stain of sputum or tracheal aspirate taken on intubation in primary pneumonia was reliably predictive of the causative organisms in both Gram-positive and Gram-negative infections when compared with infections proven by blood culture. Serologic studies were valuable in patients in whom no positive microbiologic diagnosis was evident; however, fiberoptic bronchoscopy contributed minimally to the microbiologic diagnosis in this group of patients. The cause of severe primary pneumonia differs from less severe disease, and this should be recognized when selecting empiric antibiotic therapy.

Pneumonia due to Legionella pneumophila and pneumococcal pneumonia: similarities and differences on presentation

We compared clinical, radiological and laboratory data from 32 cases of community-acquired pneumonia due to Legionella pneumophila, with 37 cases of pneumococcal pneumonia (PP). This study revealed few clinical differences between the two types of pneumonia: in our experience Legionnaire's disease presents like a "typical" bacterial pneumonia. Given the difficulty of making a diagnosis on clinical data alone, we propose early aetiological diagnostic measures and recommend that the choice of initial treatment be based not only on the features at the time of presentation, but also on a consideration of the epidemiology of different types of pneumonia in a given area.

Quantitative Use of Neufeld Reaction with Special Reference to Titration of Type II Antipneumococcic Horse Sera

The Neufeld reaction has recently been advocated for the diagnosis of the different types of pneumonia directly from the patient's sputum. For this purpose, he advised a monovalent antipneumococcic rabbit serum in order to avoid the non-specific reactions which he obtained with the use of antipneumococcic horse serum. More recently, Cooper and Walter reported this same “swelling” phenomenon when antipneumococcic serum from rabbits was mixed with the homologous pure culture grown in artificial media. This observation led us to examine different samples of antipneumococcic serum by mixing them with specific pure cultures and observing the degree of capsular swelling which resulted. It was found that a serum high in mouse protective units caused much more swelling than a serum low in mouse protective units, also that a serum of high potency could be diluted many times and still give a typical “swelling” reaction. These experiments suggested a possible quantitative application of the Neufeld reaction. Preliminary work with Type II broth cultures and specific antipneumococcus horse sera showed a definite linear relationship between the number of organisms used and the least amount of antibody required to produce an enlarged capsule. This reaction appeared to be specific. The following method of titration of Type II antibody was then developed: The culture, either live or formalinized, is diluted with 1% peptone to the required density; the serum is diluted with physiological saline solution. Appropriate amounts of a constant culture dilution and of varying serum dilutions are measured with standard platinum loops, placed on a thin cover-slip, mixed well with a loopful of methylene blue solution, and inverted on a microscope slide. These preparations are incubated 30 minutes in a moist chamber at 37°C., and then examined under a fluorite oil-immersion lens.

EXPERIMENTAL BRONCHOPNEUMONIA BY INTRABRONCHIAL INSUFFLATION

When intrabronchial insufflation of pure cultures of the streptococcus or of the influenza bacillus is properly carried out, it produces without fail a pneumonic lesion. This lesion is similar in its nature to the one known in human pathology as bronchopneumonia, and differs materially from the pneumonic lesion produced experimentally by the intrabronchial insufflation of pure cultures of the pneumococcus. Considering the fact that none of the dogs used in the experiments with the pneumococcus and none of those used in the present investigation were selected or prepared in any way, the conclusion seems to be unavoidable that the proper invasion of the microörganism is the determining factor in the development of pneumonia, the condition of the animal being only a minor element in this regard. Furthermore, since different organisms introduced in the same way and under conditions which are apparently the same produced distinctly different pneumonic lesions in animals of the same species, the further conclusion presents itself that the different types of pneumonia are produced by specifically different bacteria. However, further investigation may show that the differences in the nature of the lesion are due rather to the degree of virulence of the causative microörganism than to differences in the species; that is, that different lesions may possibly be produced by organisms of the same species, provided they possess different degrees of virulence. Further experimentation may also show that the condition of the animal and of the affected organ which, in the onset and development of the pneumonic disease, is, perhaps, unimportant, may be the leading factor in determining the course and outcome of the disease.