Detection of Pneumocystis carinii in tracheal aspirates of intubated patients using calcofluor-white (Fungi-Fluor) and immunofluorescence antibody (Genetic Systems) stains

OBJECTIVE

To compare the detection rate of Pneumocystis carinii in endotracheal aspirates with that rate in bronchoalveolar lavage fluid, using calcofluor-white (Fungi-Fluor) and immunofluorescence antibody (Genetic Systems) staining methods.

DESIGN

Prospective, consecutive cases.

SETTING

Medical intensive care unit at Ben Taub General Hospital.

PATIENTS

Thirty-one intubated patients admitted with respiratory failure and suspected P. carinii pneumonia.

INTERVENTIONS

An endotracheal aspirate specimen was obtained after maximally advancing a closed-system suction catheter, instilling aliquot portions of saline, and suctioning the lavage fluid. This procedure was followed within 30 mins by fiberoptic bronchoscopy and bronchoalveolar lavage.

MEASUREMENTS AND MAIN RESULTS

Endotracheal aspirate and bronchoalveolar lavage specimens from each patient were mixed with Saccomano's fixative, blended, and centrifuged. Using a modified method for P. carinii cysts, the sediment was stained with the test calcofluor-white stain Solution A and the test antibody stain. The test antibody stain on the bronchoalveolar lavage specimens was positive for P. carinii for 13 patients and was used as the standard for comparison. In the endotracheal aspirate specimens, the test antibody stain detected 12 (92%) P. carinii-positive patients while the test calcofluor-white stain detected ten (77%) P. carinii-positive patients.

CONCLUSIONS

We described a simple method for obtaining, processing, and staining endotracheal aspirate specimens for P. carinii. Obtaining an endotracheal aspirate specimen did not require specially trained personnel or a specialized and more expensive catheter, and was not associated with any complications.

[Acute respiratory failure secondary to Pneumocystis carinii pneumonia in children]

OBJECTIVE

The objective of this study was to ascertain the clinical and epidemiological characteristics of Pneumocystis carinii pneumonia (PCP) cases admitted to the Pediatric Intensive Care Unit (PICU).

PATIENTS AND METHODS

A retrospective study was carried out on the 8 PCP cases admitted to the PICU from July 1991 to September 1994. The variables studied were: age, sex, geographic origin, associated pathology, immunological status, clinical manifestations, biochemical data, radiology, findings in bronchoalveolar lavage fluid (BAL), response to therapy and clinical follow-up.

RESULTS

Age of the patients varied between 3 months and 9 years and there were 5 males and 3 females. Associated pathologies included AIDS (4 cases), severe combined immunodeficiency (SCID), Job's syndrome, and immunodeficiencies secondary to non-Hodgkin's lymphoma (NHL) and acute lymphoid leukemia (ALL), one case of each. Four cases appeared in a 22 day period. All cases but one suffered acute respiratory failure and needed mechanical ventilation. Diagnosis was established by means of BAL in every case. All cases showed a bilateral diffuse alveolo-interstitial pattern on chest films. Treatment was trimethoprim-sulfamethoxazole. In the acute illnesses, 2 patients died (cases of terminal SCID and NHL).

CONCLUSIONS

To date, epidemic presentation of PCP has not been reported in our community. Four of our cases, with no demonstrable previous relation, appeared over a short period of time. We have not found a relationship between LDH levels and severity, as expressed by mechanical ventilation time. Every AIDS case survived the acute episode and CD4 counts were normal in most cases.

[Respiratory failure caused by myopathy in severe sepsis]

OBJECTIVE

To describe a generalized myopathic disorder occurred in the convalescence phase of illness of a critically ill patient.

SETTING

Neurological Intensive Care Unit.

PATIENT

A 43-year-old man with acute leukoencephalopathy and severe sepsis complicated by sustained and prolonged cardiovascular, respiratory and renal failure. After 15 days of complete respiratory autonomy, the patient presented an acute ventilatory failure associated with generalized muscle weakness. Neither a relapse of sepsis nor neurological worsening were detected.

MEASUREMENTS AND RESULTS

Electromyogram resulted in normal conduction velocity in both motor and sensitive nervous fibers. Muscular biopsy showed marked fiber size variability with several hypotrophic fibers type II fiber grouping, several areas of degeneration-necrosis with macrophage invasion, dishomogeneous oxidative enzymatic activity, no increase in glycogen or lipid content.

CONCLUSIONS

These results excluded critical illness polyneuropathy and all the other known myopathies. Prolonged period of sepsis with multiple organ failure can result in a direct generalized myopathy. This possibility should be kept in mind while treating long term critically ill survivors.

Neuroborreliosis as a cause of respiratory failure

We report three cases of neuroborreliosis presenting with acute respiratory impairment. All the patients had encephalopathy and focal neurological signs with brain stem abnormalities in two. All three patients had respiratory arrest associated with progressive nocturnal hypoventilation or prolonged central apnoea. Tracheostomy and prolonged periods of ventilatory support were necessary in all cases and weaning was complicated by residual central respiratory disturbances. These cases emphasise that Borrelia infection should be considered in the differential diagnosis of unexplained respiratory failure.

Severe human psittacosis requiring artificial ventilation: case report and review

Severe respiratory failure is an uncommon manifestation of psittacosis. We describe a patient with psittacosis who developed severe respiratory failure and required artificial ventilation. We also review 11 cases reported in the English-language literature over the past 30 years. A history of exposure to birds was reported in 10 of 12 cases and remains the most significant risk factor. Severe hypoxemia or renal impairment was associated with a poor prognosis. Eight patients died of psittacosis or related complications of the infection. Diagnostic aspects, clinical manifestations, and management options are discussed.

Listeria monocytogenes and severe newborn respiratory failure supported with extracorporeal membrane oxygenation

OBJECTIVE

To determine the efficacy of extracorporeal membrane oxygenation (ECMO) in newborn infants with early-onset Listeria monocytogenes infection, necrotizing pneumonia, and severe respiratory failure.

DESIGN

Patient series.

SETTING

ECMO referral centers.

PARTICIPANTS

The Extracorporeal Life Support Organization Registry database of patients supported with ECMO between 1975 and 1991.

INTERVENTION

ECMO.

MEASUREMENTS AND RESULTS

Nine neonates were identified who were supported with ECMO for severe respiratory failure associated with L monocytogenes infection. Microbiologic studies demonstrated L monocytogenes organisms in the blood of all infants, and pneumonia was diagnosed by roentgenogram and/or isolation of L monocytogenes organisms in tracheobronchial secretions. All infants experienced progressive respiratory deterioration by age 36 hours and were placed on venoarterial bypass by 96 hours, having met institution-based criteria predictive of 80% to 90% mortality. The duration of ECMO for patients with Listeria infection (median, 210 hours; range, 137 to 454 hours) was prolonged compared with the duration of ECMO for neonates in all other registry diagnostic categories (median, 114 hours; range, 1 to 744 hours; N = 5146, P = .035). Six of the nine infants recovered completely.

CONCLUSIONS

These data suggest that ECMO is efficacious in patients with severe respiratory failure secondary to Listeria sepsis. Prolonged time on bypass should be expected when Listeria sepsis is associated with severe necrotizing pneumonia.

Pichinde virus-induced respiratory failure due to obstruction of the small airways: structure and function

Respiratory distress that leads to death is seen in patients with Lassa fever. The development of this respiratory problem was studied using a Pichinde virus model (10(4) plaque forming units, IP, survival time 20 +/- 1 days) in strain 13 guinea pigs (n = 35, 229-353 g) of this lethal human contagious infectious disease. Extravascular lung water to bloodless dry lung weight (EVLW/BDLW) ratio showed a modest yet significant increase in animals 13 and 18-21 days postinoculation (PI). In contrast, residual lung blood and lung radioactive 125I-labeled human serum albumin activity index were elevated only in the 18- to 21-day group. These data are consistent with the progressive severity of perivascular edema, lymphocytic pneumonitis, and some alveolar protein between days 13 and 18-21 PI. Lymphocytic pneumonitis appeared to be distributed near most airways and was proportional to the degree of Pichinde virus antigen staining of alveolar macrophages, large mononuclear cells within the pulmonary vascular and extravascular spaces, and alveolar-capillary membranes. These findings suggest that lymphocyte recruitment to the lung reflects the Pichinde virus-induced cell-mediated immune response. Obstructed small bronchi with some lumenal cell debris and hypertrophied epithelial cells were found associated with the areas of marked pneumonitis. The severe hypoxemia and modest anaerobic metabolism in association with marked tachypnea and normocapnia are consistent with small airway obstruction and wasted ventilation, since no change in arterial blood pressure, heart rate, hematocrit, hemoglobin, or blood volume was noted. These data suggest that Pichinde virus-induced respiratory failure was due to obstruction of the small airways with wasted ventilation in association with lymphocytic pneumonitis.

Failure of tracheal aspirate cultures to define the cause of respiratory deteriorations in neonates

The spectrum of organisms responsible for lower respiratory tract infection in chronically ventilated neonates is poorly defined. During an 18-month period 63 infants with a respiratory deterioration defined as an increase in fractional inspired O2 concentration > or = 20% and/or mean airway pressure > or = 3 cm H2O were evaluated for pulmonary infection. These infants were compared with 58 stable control ventilated infants. Tracheal aspirates for culture and Gram stain were taken from both groups and were cultured for bacteria, viruses, Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis. In addition each infant had complete blood counts with differential and chest roentgenograms evaluated. Positive tracheal aspirates defined as a heavy growth of a single or two bacterial organisms, and/or any growth of virus, Chlamydia and U. urealyticum were found in 23 of 63 study patients and 20 of 58 controls (P > 0.05). The most frequent isolate in both groups was U. urealyticum. Chest radiographs were positive (new changes, particularly atelectasis and infiltrates) more frequently in the study group than in controls, but complete blood count and tracheal aspirate Gram-stained smears were not helpful in discerning colonization from infection. We conclude that positive tracheal aspirates occur with equal frequency among infants with a clinical suspicion of lower respiratory tract infection and in "well" controls. Chest roentgenogram may be a useful adjunctive test to discriminate between colonization and lower respiratory tract infection.

The course of nosocomial oropharyngeal colonization in patients recovering from acute respiratory failure

We sought to determine the duration of nosocomially acquired Gram-negative bacilli (GNB) oropharyngeal colonization following hospitalization for acute respiratory failure (ARF). We selected 24 inpatients recovering from ARF who had positive oropharyngeal cultures for GNB. Follow-up cultures were obtained at the time of hospital discharge, and 2 and 4 weeks afterwards. The prevalence of GNB colonization in these patients was 14/21 (67 percent) at the time of hospital discharge and 14/23 (60 percent) 2 weeks afterwards. Both rates were greater than the control population's 7/30 (23 percent, p < 0.02 and < 0.05, respectively). Four weeks after hospital discharge, the prevalence of colonization had fallen to 7/19 (37 percent) which was not significantly different from that of controls. Five of 24 subjects were rehospitalized during the follow-up period. Pneumonia was diagnosed in only two of the five and both proved to be due to pathogens other than GNB. We conclude that the prevalence of GNB oropharyngeal colonization following ARF approaches control levels within four weeks of hospital discharge. We speculate that a post-ARF patient's risk for GNB pneumonia similarly declines.

Uvulitis in three children: etiology and respiratory distress

Uvulitis is an uncommonly reported disorder with the potential for significant morbidity. We describe three cases of uvulitis seen within a six month period in our emergency department. In two cases with respiratory distress, but without epiglottitis, Haemophilus influenzae was isolated from throat or blood cultures. The third case was associated with group A streptococcus tonsillitis and no respiratory compromise. Atypical presentations of upper airway infection with H. influenzae may be increasingly common.

[Relation of bacterial flora between upper and lower respiratory tracts in patients with long-term tracheostomy]

Throat secretions (TS) and bronchial secretions aspirated from tracheostomy (TSTA) were cultured at the same time in 9 subjects with long term tracheostomy every two weeks from January, 1990 to December, 1990. Total number of each examination in TS and TSTA were 200 times. Mean number of bacteria isolated by single culture were 2.9 strains in TS and 1.8 strains in TSTA. Isolated bacteria were mainly alpha-Streptococcus (84.8%) and Neisseria (69%) in TS, and Pseudomonas aeruginosa (53.5%) and Serratia marcescens (30%) in TSTA. Only 20% of P. aeruginosa or S. marcescens in TSTA were isolated from TS. In 8 cases of 9, P. aeruginosa in TSTA were isolated with every time or long term. There were 14 episodes of respiratory infections in 6 cases. P. aeruginosa were causative organisms in 7 episodes. It suggests that P. aeruginosa tended to colonize in lower respiratory tracts of the patients with long term tracheostomy and to become causative organisms in respiratory infections.

[Lower respiratory tract flora in intubated patients]

200 lower respiratory tract (LRT) aspirates were taken via endotracheal intubates in 49 respiratory failure patients for quantitative bacterial cultures. 373 strains of bacteria and fungi were isolated and 63.3% were gram negative bacilli (GNB). During intubation, the isolation rate of Pseudomonas species gradually increased. In recent years, Enterobacteriaceae species, S. pneumoniae and S. aureus as LRT flora are decreasing, but Pseudomonas species, is increasing. The bacteria in aspirates with concentration higher than 10(5)CFU/ml could be considered as etiologic bacteria. Accordingly we estimated that the GNB infection rate was 81.6% and fatality rate was 15.0% in these 49 cases. Bacteriologic survey of the patients' oropharynx, respiratory instrument and the medical workers' finger skin suggested that besides the descending of oropharynx flora, environmental bacteria may also form LRT flora via endotracheal intubates.

Lung vascular injury after administration of viable hemolysin-forming Escherichia coli in isolated rabbit lungs

Escherichia coli hemolysin, a transmembrane pore-forming exotoxin, is considered an important virulence factor. In the present study, the possible significance of hemolysin production was investigated in a model of septic lung failure through infusion of viable bacteria in isolated rabbit lungs; 10(4) to 10(7) E. coli/ml perfusate caused a dose- and time-dependent appearance of hemolysin, accompanied by release of potassium, thromboxane A2, and PGI2 into the perfusate. Concomitantly, marked pulmonary hypertension developed. Inhibitor studies suggested that the pressor response was predominantly mediated by pulmonary thromboxane generation. Administration of hemolysin-forming E. coli additionally caused a protracted, dose-dependent increase in the lung capillary filtration coefficient, followed by severe edema formation. The permeability increase was independent of lung prostanoid generation. An E. coli strain that releases an inactive form of hemolysin completely failed to provoke the described biophysical and biochemical responses. Preapplication of 2 x 10(8) human granulocytes was without effect in the present experimental model. We conclude that the hemolysin produced by low numbers of E. coli organisms can provoke thromboxane-mediated pulmonary hypertension and severe vascular leakage. E. coli hemolysin and, possibly, other related cytolysins may thus contribute directly to the pathogenesis of acute respiratory failure under conditions of sepsis or pneumonia.

Diffuse pneumonia and acute respiratory failure due to infectious mononucleosis in a middle-aged adult

This report describes a 48-yr-old patient who developed bilateral hilar adenopathy, diffuse pulmonary infiltrates, and respiratory failure in association with infectious mononucleosis. Lung and paratracheal lymph node biopsies suggested the diagnosis, and an acute Epstein-Barr virus infection was confirmed serologically. Pulmonary involvement in infectious mononucleosis is reviewed, and atypical features, which may lead to diagnostic difficulty, particularly in the older adult, are discussed.

[Pulmonary Pseudomonas infections]

145 strains of pathogenic pseudomonas had been isolated from the sputum or bronchoscopic aspirate of 1423 patients with pulmonary infections. They were classified into 8 types, among which 31.7% was pseudomonas aeruginosa. Pseudomonas aeruginosa was the dominant causative organism in pulmonary infections of the aged while in presenile ones the organism was mainly Pseudomonas fetid. The incidence of nosnocomial pseudomonas infection in patients of COPD with respiratory failure was 40%, of COPD with pulmonary infection 9.1% and of others 6.6%. 24 pseudomonas carriers with COPD (colonies less than or equal to 10(6)/ml in sputum) had been followed up. 16 out of them became negative in sputum culture without any treatment, while the remaining 8 developed pulmonary pseudomonas infections. 21 patients (14.5%) were found to have other types of pseudomonas infections during antibiotic treatment. Sensitivity tests showed that third-generation cephalosporins and aminoglycosides had definite antimicrobial activity against pseudomonas, the former being more stable and effective than the latter.