Nonbacteremic Pneumonia Research Articles

Economic evaluation of delivering Haemophilus influenzae type b vaccine in routine immunization services in Kenya.

Haemophilus influenzae type b (Hib) vaccine was introduced into routine immunization services in Kenya in 2001. We aimed to estimate the cost-effectiveness of Hib vaccine delivery. A model was developed to follow the Kenyan 2004 birth cohort until death, with and without Hib vaccine. Incidence of invasive Hib disease was estimated at Kilifi District Hospital and in the surrounding demographic surveillance system in coastal Kenya. National Hib disease incidence was estimated by adjusting incidence observed by passive hospital surveillance using assumptions about access to care. Case fatality rates were also assumed dependent on access to care. A price of US$ 3.65 per dose of pentavalent diphtheria-tetanus-pertussis-hep B-Hib vaccine was used. Multivariate Monte Carlo simulations were performed in order to assess the impact on the cost-effectiveness ratios of uncertainty in parameter values. The introduction of Hib vaccine reduced the estimated incidence of Hib meningitis per 100,000 children aged < 5 years from 71 to 8; of Hib non-meningitic invasive disease from 61 to 7; and of non-bacteraemic Hib pneumonia from 296 to 34. The costs per discounted disability adjusted life year (DALY) and per discounted death averted were US$ 38 (95% confidence interval, CI: 26-63) and US$ 1197 (95% CI: 814-2021) respectively. Most of the uncertainty in the results was due to uncertain access to care parameters. The break-even pentavalent vaccine price--where incremental Hib vaccination costs equal treatment costs averted from Hib disease--was US$ 1.82 per dose. Hib vaccine is a highly cost-effective intervention in Kenya. It would be cost-saving if the vaccine price was below half of its present level.

Effect of Pneumococcal Vaccination: A Comparison of Vaccination Rates in Patients with Bacteremic and Nonbacteremic Pneumococcal Pneumonia

Despite the widespread acceptance of the 23-valent pneumococcal capsular polysaccharide vaccine (PPV), its protective effect continues to be disputed. We describe a novel approach to examine the protective effect of this vaccine. We recorded the vaccination status of every patient for whom a culture yielded Streptococcus pneumoniae during a 4.5-year period, comparing rates of prior PPV administration in patients with (1) bacteremic pneumococcal pneumonia, (2) all-invasive pneumococcal disease, (3) nonbacteremic pneumococcal pneumonia, (4) acute exacerbation of chronic bronchitis (AECB) due to S. pneumoniae, and (5) pneumococcal colonization. The principal comparisons were with patients who had bacteremic pneumonia or any invasive pneumococcal disease and those with nonbacteremic pneumococcal pneumonia. We also compared vaccination rates in patients who had nonbacteremic pneumonia with vaccination rates in patients with AECB or pneumococcal colonization. The rate of prior PPV vaccination was lower among patients with bacteremic pneumococcal pneumonia (39.7%) or any invasive pneumococcal disease (38.0%) than among patients with nonbacteremic pneumonia (57.6%), AECB (60.0%), or pneumococcal colonization (57.8%). PPV conferred a 54% protection rate against bacteremic versus nonbacteremic pneumococcal pneumonia. There was no apparent protection against nonbacteremic pneumonia compared, for example, with colonized persons or with those who had AECB. PPV provides moderate protection against invasive pneumococcal disease but does not protect against nonbacteremic pneumococcal pneumonia. These findings suggest the importance of a continued search for a better pneumococcal vaccine.

Drug‐resistant genes and serotypes of pneumococcal strains of community‐acquired pneumonia among adults in Japan

A high frequency of drug-resistant pneumococci has been reported in Asian countries. Few data on the drug-resistance or serotype of pneumococcal strains responsible for community-acquired pneumonia (CAP), however, are available for the past two decades in Japan. Susceptibility to antibiotics and the genotype of antibiotic-resistant genes and serotypes of Streptococcus pneumoniae isolates from 114 adult patients with CAP were examined in a nationwide study in Japan between 2001 and 2003. Most of the cases were non-bacteraemic pneumonia and the case fatality rate was 4.4%. The most frequent genotype of the pbp gene was pbp1a + 2x + 2b (gPRSP; 36.8%) followed by pbp 2x (28.1%) and of the macrolide-resistant gene, it was ermB (50.0%). The most common serotype was 19F (29.1%), followed by serotype 23F (13.2%), 6B (12.3%) and 3 (11.4%). The coverage of serotypes of isolates by a 23-valent pneumococcal polysaccharide vaccine (PPV) would be 82.5% in these patients with CAP. Most of strains with serotypes 19F and 23F were gPRSP. A cluster of serotype 3 strains associated with the pbp 2x and ermB gene was also noted. A high frequency of altered pbp gene mutations or of macrolide-related genes and a high serotype coverage by the 23-valent PPV found in our study of pneumococcal pneumonia facilitates attempts to increase the coverage rate of the 23-valent PPV in adults older than 65 years in Japan.

Procalcitonin and neopterin correlation with aetiology and severity of pneumonia

Clinical outcome of pneumonia depends on a multifaceted treatment approach. Not only diagnostic methods but also early indicators of the degree of inflammatory response can aid in therapeutic decisions. The objective was to evaluate the usefulness of procalcitonin and neopterin in distinguishing among aetiologies as well as severity in patients with pneumonia. A total of one hundred sixteen patients with clinical, radiographic and microbiological diagnosis of pneumonia were grouped by aetiology, pneumonia severity index, and by the presence of unilobar or multilobar radiographic pulmonary infiltrates. Procalcitonin and neopterin were measured by immunoassays. Patients with pneumococcal pneumonia presented elevated procalcitonin and neopterin levels, being higher in bacteraemic than in non-bacteraemic pneumonia. Patients with Legionella pneumonia presented elevated neopterin levels and slightly elevated procalcitonin levels. Patients with tuberculosis and Pneumocystis jirovecii pneumonia presented elevated neopterin and low or not detectable procalcitonin. Procalcitonin and neopterin levels were increased in high-risk classes of pneumonia severity index. Both parameters yielded significant correlation to the radiographic extent and also to young age. Procalcitonin and neopterin levels vary depending on age, aetiology and severity of pneumonia. Together with clinical and microbiological data, combined measurement can help to identify patients who might benefit from additional therapies.

Effectiveness of Haemophilus influenzae b conjugate vaccine on childhood pneumonia: a case-control study in Brazil.

The conjugate Haemophilus influenzae type b (Hib) vaccine has been highly efficacious in reducing type b H. influenzae meningitis. However, information is limited about its impact on childhood pneumonia after vaccine introduction into the routine programme. This study evaluated the effectiveness of Hib conjugate vaccine in the reduction of community-acquired pneumonia among infants in Central Brazil. A matched case-control study was built into an ongoing prospective population-based surveillance of pneumonia, enrolling 1293 participants between May 2000 and August 2001. Cases (n = 431) were children <or=2 years old hospitalized with radiologically definite pneumonia according to the World Health Organization standard criteria for the interpretation of radiographs for the diagnosis of pneumonia. Two controls (n = 862) without previous hospitalization for pneumonia were identified among children from the same neighbourhood and matched to cases by age stratum (+/-4 months). The Hib vaccination effectiveness was estimated as 1 minus odds ratio (OR). The greatest risk factor for pneumonia among children <2 years of age was day-care centre attendance (P < 0.001). Of the study participants, 83.3% (1072/1287) were classified as vaccinated according to immunization card and 16.7% (215/1287) were considered unvaccinated. By using conditional logistic regression the vaccine effectiveness was estimated as 31.0% (95% CI: -9.0%, 57.0%) after adjusting for sex, previous flu-like illnesses, day-care attendance, smokers at home, house ownership, mother's education, and age as continuous variable. Under programme conditions the effectiveness of Hib conjugate vaccine in infants with radiologically confirmed pneumonia was 31% (95% CI: -9%, 57%) showing the potential benefit of Hib immunization in the prevention of likely non-bacteraemic pneumonia.

The cost-effectiveness of pneumococcal conjugate vaccination in Australia

Background: Pneumococcal conjugate vaccine, 7 valent (PCV7) is the most costly vaccine yet considered for publicly funded programs. In mid 2001, Australia funded PCV7 for high-risk groups only (indigenous children and children with certain underlying medical conditions). World wide, non-industry-funded studies and studies using cost–utility measures are sparse. We undertook an independent economic analysis of PCV7 compared with no vaccination in the non high-risk Australian childhood population using cost–utility and cost-effectiveness measures. Methods: The incidence of invasive pneumococcal disease (IPD), non-bacteraemic pneumonia and otitis media was estimated using representative urban Australian data, or by extrapolation from comparable industrialised countries. A decision-analytic model was developed for a hypothetical birth cohort using the age-specific vaccine coverage from the Californian randomised controlled trial of PCV7. Health outcomes were measured by life-years saved and deaths and disability-adjusted life-years (DALYs) averted. In line with government guidelines, only direct costs were considered in 1997–1998 Australian dollars. Results: For a birth cohort of 250,000, the gross cost of vaccination is $ 78.6 million. Subtracting treatment cost savings, the net cost (discounted) is $ 61.7 million. In undiscounted terms, vaccination prevents 13.7 deaths, 11.2 (82%) from IPD and the remainder from non-bacteraemic pneumonia. The discounted cost per death avoided is $ 5.0 million, per life-year saved $ 230,130 and per DALY averted $ 121,100, giving a break-even vaccine price of $ 15.40 per dose. These estimates are most sensitive to the unit cost per dose of vaccine, estimates of incidence and vaccine efficacy against non-bacteraemic pneumonia and the discount rate. The cost per DALY reduced to $ 81,000 with a discount rate of 3% rather than 5% and to $ 90,000 with the most favourable assumptions concerning pneumonia reduction. Discussion: With a vaccine price of $ 90 per dose, mid-range estimates of impact against non-bacteraemic pneumonia, and discount rate of 5%, a PCV7 program for infants not at high risk of IPD is at the upper limit of cost per DALY previously approved under Australian pharmaceutical funding guidelines. The impact of PCV7 against non-bacteraemic pneumonia is poorly defined, but its importance to cost-effectiveness in resource rich and resource poor settings warrants further studies or analysis to give greater precision to this outcome.

Pneumococcal vaccination and pneumonia: even a low level of clinical effectiveness is highly cost-effective.

Most studies of the cost-effectiveness of pneumococcal vaccination show very favorable cost-effectiveness ratios for preventing pneumococcal pneumonia, but they make the controversial assumption that vaccination is equally effective in preventing bacteremic (BPP) and nonbacteremic (NBPP) pneumonia. However, the results of our study showed that, compared with preventing BPP alone, the cost-effectiveness of pneumococcal vaccination increased substantially even when only a small proportion of additional cases of NBPP were prevented.

Detection of Streptococcus pneumoniae Antigen by a Rapid Immunochromatographic Assay in Urine Samples

Evaluation of a newly available rapid (15 min) immunochromatographic membrane test (ICT) to detect Streptococcus pneumoniae in urine samples, in order to assess its utility in the diagnosis of bacteremic and nonbacteremic pneumococcal pneumonia. Retrospective study. We studied urine samples from 51 patients with bacteremic and nonbacteremic pneumonia due to S pneumoniae diagnosed by blood culture and pneumococcal polysaccharide capsular antigen detection by counterimmunoelectrophoresis in urine samples, 16 patients with probable pneumococcal pneumonia, 71 patients with nonpneumococcal pneumonia, and 16 patients with pneumonia but no pathogen identified. Urine samples were collected and frozen at - 20 degrees C until used. The ICT test was performed following the instructions of the manufacturer. S. pneumoniae antigen was detected in 41 of 51 patients with pneumococcal pneumonia (80.4%); results were positive in 23 of 28 bacteremic cases (82.1%) and in 18 of 23 nonbacteremic cases (78.3%). From patients with a diagnosis of presumptive pneumococcal pneumonia, antigen was detected in seven urine samples (43.7%) and also in one case of the 16 patients with pneumonia but no pathogen identified. The specificity of the ICT test was 97.2%. The ICT assay is a valuable tool for the diagnosis of pneumococcal pneumonia, especially for the nonbacteremic cases.

Burden of meningitis and other severe bacterial infections of children in africa: implications for prevention.

Apart from meningococcal disease in the sub-Saharan meningitis belt, the incidence and impact of life-threatening bacterial diseases in children across Africa have not been quantified. The clinical and epidemiological data on pneumococcal, Haemophilus influenzae type b (Hib), and other forms of bacterial meningitis, as well as data on other severe bacterial infections throughout the continent were scrutinized. Pneumococci were the leading causative agents of nonepidemic meningitis and other bacteremic diseases, followed by Hib. Meningococcal diseases were less common. Mortality rates associated with pneumococcal, Hib, and meningococcal meningitis were 549 (45%) of 1211 patients, 389 (29%) of 1352 patients, and 104 (8%) of 1236 patients, respectively; sequelae occurred in 50%, 40%, and 10% of cases. At 0-4 years of age, the estimated incidences of Hib meningitis and all classic Hib diseases were 70 and 100 cases per 100,000 population per year, accounting for approximately 90,000 and 120,000 cases per year, respectively. Including older age groups and, especially, nonbacteremic Hib pneumonia in the estimates of Hib disease in Africa increased the overall numbers manifold; the numbers of pneumococcal infections were even greater. The only realistic way to combat these severe infections efficaciously would be through widespread vaccination, starting with Hib conjugates.

Worldwide Haemophilus influenzae Type b Disease at the Beginning of the 21st Century: Global Analysis of the Disease Burden 25 Years after the Use of the Polysaccharide Vaccine and a Decade after the Advent of Conjugates

Vaccination against Haemophilus influenzae type b (Hib) diseases began a quarter of a century ago with a polysaccharide vaccine; this vaccine was followed by four different conjugates 10 years later. In this review, the burden of global Hib disease is quantified following this 25-year period of vaccine availability to determine the potential impact of conjugate vaccines. This task was accomplished by analysis of data available in 10 languages in 75 geographical regions of over 50 countries. All severe Hib diseases, not only meningitis, were characterized, and special attention was paid to the most vulnerable age group, i.e., children aged 0 to 4 years. Prior to vaccination, the weighted worldwide incidence of meningitis in patients younger than 5 years was 57/100,000, and for all Hib diseases except nonbacteremic pneumonia, it was 71/100,000, indicating 357,000 and 445,000 cases per year, respectively. At least 108,500 of these children died. For all age groups combined, there were 486,000 cases of Hib disease, excluding pneumonia, with 114,200 deaths and probably an equal number of sequelae per annum. If the figures for nonbacteremic pneumonia are included, a conservative estimate is that over 2.2 million cases of infection and 520,000 deaths from Hib disease occurred worldwide, but the true numbers might have been greater. Despite these large numbers and availability of safe and efficacious vaccines, only 38,000 cases annually are prevented-a meager 8% or less than a 2% reduction in cases, depending on whether nonbacteremic pneumonia is included in the calculations. Although vaccination has had great success in some affluent countries, the current level of activity has had a very small impact globally. The use of conjugates, preferably with a reduced number of doses and in combination with other vaccines or perhaps in fractional doses, should be extended to less privileged countries, where most Hib disease occurs.

Worldwide Haemophilus influenzae type b disease at the beginning of the 21st century: global analysis of the disease burden 25 years after the use of the polysaccharide vaccine and a decade after the advent of conjugates.

Vaccination against Haemophilus influenzae type b (Hib) diseases began a quarter of a century ago with a polysaccharide vaccine; this vaccine was followed by four different conjugates 10 years later. In this review, the burden of global Hib disease is quantified following this 25-year period of vaccine availability to determine the potential impact of conjugate vaccines. This task was accomplished by analysis of data available in 10 languages in 75 geographical regions of over 50 countries. All severe Hib diseases, not only meningitis, were characterized, and special attention was paid to the most vulnerable age group, i.e., children aged 0 to 4 years. Prior to vaccination, the weighted worldwide incidence of meningitis in patients younger than 5 years was 57/100,000, and for all Hib diseases except nonbacteremic pneumonia, it was 71/100,000, indicating 357,000 and 445,000 cases per year, respectively. At least 108,500 of these children died. For all age groups combined, there were 486,000 cases of Hib disease, excluding pneumonia, with 114,200 deaths and probably an equal number of sequelae per annum. If the figures for nonbacteremic pneumonia are included, a conservative estimate is that over 2.2 million cases of infection and 520,000 deaths from Hib disease occurred worldwide, but the true numbers might have been greater. Despite these large numbers and availability of safe and efficacious vaccines, only 38,000 cases annually are prevented-a meager 8% or less than a 2% reduction in cases, depending on whether nonbacteremic pneumonia is included in the calculations. Although vaccination has had great success in some affluent countries, the current level of activity has had a very small impact globally. The use of conjugates, preferably with a reduced number of doses and in combination with other vaccines or perhaps in fractional doses, should be extended to less privileged countries, where most Hib disease occurs.

Defining the burden of pneumonia in children preventable by vaccination against Haemophilus influenzae type b.

To determine the burden of pneumonia requiring hospitalization in infants and young children preventable by vaccination against Haemophilus influenzae type b (Hib). Vaccination centers in Santiago, Chile, were randomly selected to administer PRP-T, an Hib conjugate vaccine, combined with diphtheria-tetanus toxoids-pertussis (DTP) vaccine or DTP alone. Infants who received > or =2 doses of DTP or DTP and Hib conjugate vaccine combined. Pneumonia episodes leading to hospitalization accompanied by indicators of likely bacterial infection including radiologic evidence of alveolar consolidation or pleural effusion, an elevated erythrocyte sedimentation rate (> or =40 mm/h) or bronchial breath sounds on auscultation. In participants age 4 to 23 months, PRP-T reduced the incidence of pneumonia associated with alveolar consolidation or pleural effusion by 22% (95% confidence interval, -7 to 43) from 5.0 to 3.9 episodes per 1000 children per year. When the pneumonia case definition included any of the following, alveolar consolidation, pleural effusion, erythrocyte sedimentation rate > or =40 mm/h or bronchial breath sounds, PRP-T provided 26% protection (95% confidence interval, 7 to 44) and prevented 2.5 episodes per 1000 children per year. Hib vaccine provides substantial protection against nonbacteremic pneumonia, particularly those cases with alveolar consolidation, pleural effusion or other signs of likely bacterial infection. Hib vaccination prevented approximately 5 times as many nonbacteremic pneumonia cases in infants as meningitis cases, thus indicating that the largest part of the effect of Hib vaccination might be undetectable by routine culture methods.

Bacteremic pneumococcal pneumonia: bone marrow release and pulmonary sequestration of neutrophils.

Neutrophils have been implicated in the pathogenesis of acute lung injury in bacteremic pneumococcal pneumonia. The characteristics of the population of neutrophils that injure the lung are still not known. This study was designed to compare the bone marrow release and lung sequestration of neutrophils during bacteremic pneumococcal pneumonia with nonbacteremic pneumonia and isolated bacteremia. Prospective, controlled, experimental study. University research laboratory. Female New Zealand white rabbits (n = 17; weight 2.3 to 2.7 kg). The rabbits were pretreated with intravenous 5'-bromo-2-deoxyuridine (BrdU 100 mg/kg i.v.) to pulse label dividing neutrophils in the bone marrow. Twenty hours after the treatment with BrdU, the rabbits were anesthetized and pneumonia was induced by instilling Streptococcus pneumoniae (1.5 x 10(9) organisms) into the lower lobe of the lung. Four hours after pneumonia, bacteremia was induced by infusing S. pneumoniae (3.0 x 10(9) organisms) into the circulation (pneumonia + bacteremia: n = 6). These animals were compared with those with just pneumonia (n = 5) or bacteremia (n = 6). White blood cell, neutrophil, and differential count. BrdU-labeled neutrophils (neutrophilBrdU) were identified using immunohistochemistry. Cells in tissues were examined microscopically, using sequential level stereologic analysis. The pneumonia + bacteremia group developed a leukopenia (7.3 +/- 0.7 to 2.4 +/- 0.2 x 10(9)/L) following the bacteremia that was associated with an increase in circulating band cells and neutrophilBrdU (2.3 +/- 0.8% to 33.5 +/- 2.8%) which were both higher than those in the other groups (p < .005). Bone marrow smears showed accelerated maturation of neutrophils in the pneumonia + bacteremia group (neutrophilBrdU increased from 11.6 +/- 1.0 to 45.3 +/- 2.1%). Morphometric studies of the lung showed increased neutrophil sequestration in the untreated lung tissue of the pneumonia + bacteremia group (16 +/- 0.8 x 10(8)/mL tissue) compared with the pneumonia (6.6 +/- 0.3 x 10(8)/mL tissue) and bacteremia (12 +/- 0.6 x 10(8)/mL tissue) groups (p < .0001). NeutrophilBrdU preferentially sequester in the lungs of all groups but were slow to migrate into the alveolar air spaces (p < .05). During bacteremic pneumococcal pneumonia there is an accelerated maturation of neutrophils in the bone marrow with an enhanced release of neutrophils into the circulation. These newly released neutrophils preferentially sequester in lung microvessels but are slow to migrate into the alveolar air space.

Detection of pneumococcal polysaccharide antigens in the urine of patients with bacteraemic and non-bacteraemic pneumococcal pneumonia

Countercurrent-immunoelectrophoresis (CIE) was used to detect pneumococcal capsular polysaccharide and C-polysaccharide (C-Ps) antigens in urine.The neutral capsular polysaccharides of types 7F and 14 were detected by coagglutination.We found pneumococcal polysaccharide in urine with the same frequency in two groups of patients, i.e.a nonbacteraemic pneumonia group (68%) and a group of patients with pneumococcal bacteraemia (66%).C-Ps was detected in the urine of two patients (4%) and, therefore, this test has no value in the diagnosis of pneumococcal infections.Since there is no sensitive, noninvasive, single procedure for the diagnosis of non-bacteraemic pneumococcal pneumonia we conclude that attempts to detect pneumococcal capsular polysaccharide by CIE in combination with coagglutination (types 7F and 14) may be a useful diagnostic supplement in the search for the etiological agent in pneumonia in adults until new, more sensitive diagnostic methods have been developed.

Pneumonia caused by gram-negative bacilli

Gram-negative bacillary pneumonia has become an increasingly important disease in immunosuppressed, elderly, and hospitalized patients. The clinical features, etiologic agents, population at risk, treatment, and outcome in patients with well-documented gram-negative pneumonia were compared in two groups of patients: those with bacteremic pneumonia and those with nonbacteremic pneumonia documented by transtracheal aspiration. Clinical features were frequently subtle in both groups. A wide range of gram-negative bacilli were implicated as pathogens and pneumonias documented by transtracheal aspiration were frequently mixed infections. Pseudomonas aeruginosa and Serratia marcescens were the most common pathogens causing bacteremic pneumonias, whereas Escherichia coil and Klebsiella were more common in the nonbacteremic group. Gram-negative bacillary pneumonia was frequently a lethal disease despite two-drug therapy, particularly in bacteremic patients.

Clinical Significance of Serotype, Biotype, and βLactamase Production of Respiratory Isolates of Hemophilus influenzae

The correlation between clinical significance and serotype, biotype, and beta-lactamase production of 101 respiratory isolates of Hemophilus influenza from nonbacteremic patients was determined. Six of 33 (18.2%) isolates from patients with definite or probable infection were serotypable; only two of 67 (3%) isolates from colonized patients were serotypable. Eight-seven and one-half per cent of the serotypable strains were biotypes I or IV; 78.8% of nonserotypable strains were biotypes II, III, or V. Biotype distribution among isolates from patients with definite or probable infection were similar to isolates from colonized patients. beta-lactamase production was not helpful in evaluating clinical significance. Nonserotypable H. influenzae is an important cause of nonbacteremic pneumonia in elderly men.

Enhancement of non-specific resistance to Pseudomonas pneumonia by a synthetic derivative of muramoyl dipeptide in immunosuppressed guinea pigs.

A synthetic derivative of muramoyl dipeptide, 6-O-stearoyl-N-acetylmuramoyl-L-alanyl-D-isoglutamine [L18-MDP(A)], showed a protective effect against bacteraemic and non-bacteraemic pneumonia caused by Pseudomonas aeruginosa in immunosuppressed guinea pigs. In about half of the animals treated with the compound before infection, death from bacteraemic pneumonia produced by intratracheal inoculation of P. aeruginosa was delayed for 7 d, although all of the animals infected without prior treatment with the compound died within 4 d of infection. Multiplication of the organisms in the lung was also suppressed for at least 10 d by treatment with the compound when the animals inhaled an aerosol of P. aeruginosa. In contrast, in untreated animals the numbers of bacteria in the lung gradually increased from 10(6) to 10(9) c.f.u. g-1, and a few animals in which the organism increased to 10(9) c.f.u. g-1 had died by 6 and 10 d after infection. In both healthy and immunosuppressed animals, the accumulation of polymorphonuclear leukocytes (PMNs) in a subcutaneous air-pouch injected with heat-killed organisms was augmented by subcutaneous treatment with L18-MDP(A) 1 d before bacterial injection. The phagocytic activity of peritoneal PMNs was also increased by treatment with this compound. The augmentation of protective mechanisms against pseudomonas pneumonia by L18-MDP(A) may be attributed at least partly to the increased chemotactic and phagocytic activity of PMNs.

Nonbacteremic Pseudomonas Pneumonia in Immunosuppressed Guinea Pigs

An experimental model of nonbacteremic pneumonia with a virulent strain of Pseudomonas aeruginosa was successfully established in guinea pigs immuno-suppressed with cortisone acetate although the organisms were eliminated rapidly from the lungs without cortisone treatment. Using a pocket nebulizer, almost all the animals which received 10(6) organisms/g-lung developed bronchopneumonia without any septic findings as long as 10 days after challenge. The lesions produced in such animals were characterized by dissemination of multiple purulogranulomatous changes. In the early stage of infection, infiltration of polymorphonuclear cells (PMNs) in the bronchiolar and alveolar spaces was diffuse, later showing multifocal accumulation with the formation of central spherical grains enclosing bacterial colonies. In the later stage, granulation tissue consisting of large mononuclear cells, fibroblasts and collagen fibers developed around the PMN accumulation. The animals which received 10(7) organisms/g-lung, on the other hand, developed severe pulmonary hemorrhages and necrosis followed by septic death.

Roentgenologic aspects of primary Pseudomonas aeruginosa pneumonia in mechanically ventilated patients.

ROENTGENOLOGIC ASPECTS OF PRIMARY PSEUDOMONAS AERUGINOSA PNEUMONIA IN MECHANICALLY VENTILATED PATIENTSNORMAN JOFFE, M.B.Audio Available | Share

Characteristics of nonbacteremic Pseudomonas pneumonia.

Abstract The distinguishing clinical course, laboratory findings, and morbid anatomy of nonbacteremic pseudomonas pneumonia is described. These infections occurred in ten patients (eight of whom ul...