Protective effect of montelukast on lower and upper respiratory tract responses to short-term cat allergen exposure.

BACKGROUND: Challenge with short-term exposure to airborne cat allergen in sensitized patients produces pulmonary function changes and rhinitis symptoms. OBJECTIVE: To determine the benefit of montelukast, 10 mg, for patients with concomitant asthma and allergic rhinitis as demonstrated by protection against both lower and upper airway responses to cat allergen challenge. METHODS: This randomized, crossover study treated patients with montelukast vs placebo during two 2-week, double-blind treatment periods, separated by a 1-week washout period. After each treatment period, patients underwent a 60-minute or less exposure to high levels of airborne cat allergen. Lower and upper airway responses were measured by spirometry and symptom scores. RESULTS: Of 52 patients with data from both treatment arms, 79% of patients taking montelukast and 67% taking placebo were exposed to the full 60-minute allergen challenge. Montelukast provided significant (P < or = .001) protection against allergen challenge in the lower airway coprimary end point of area under the curve during challenge (AUC0-60min) for percentage decrease in forced expiratory volume in 1 second: mean of 10.5% per hour and 14.7% per hour for montelukast and placebo, respectively. Although the effect on the overall nasal symptoms score (NSS) coprimary end point of AUC0-60min was not statistically significance (P = .12), nasal congestion during the challenge and NSS during recovery showed statistically significant (P = .048) protection by montelukast. Additional analyses of simultaneous lower and upper airway responses showed that more patients taking montelukast (22, 43%) vs placebo (13, 26%) were protected from both asthma and rhinitis (P = .02), with an odds ratio of 2.24 (95% CI, 1.16-4.32) in favor of montelukast. CONCLUSIONS: Montelukast has a protective effect against both lower and upper airway responses during exposure to high levels of cat allergen.     

Beta-lactamase production in the upper respiratory tract flora

In order to determine the recovery rate of species of the genera Haemophilus and Moraxella (including subgenus Branhamella) from the upper respiratory tract and the incidence of -lactamase production within these genera, cultures were made of nose and throat swab specimens and adenoid tissue in 50 children undergoing adenoidectomy.Haemophilus influenzae was isolated from 92% of the children. All children harboured strains of Haemophilus spp. and in 46%, at least one strain produced the TEM-1 -lactamase.Branhamella catarrhalis and/or Moraxella nonliquefaciens were isolated from 82% of the children and strains producing the BRO-1 -lactamase from 34%. Overall, TEM-1 and/or BRO-1 producing strains were recovered from 60% of the investigated patients. The -lactamase production was found to be transferable by conjugation within the respective genera. It is suggested that the apathogenic species may be a source of transferable determinants mediating -lactamase production in the upper respiratory tract.     

The nature of myospherulosis of the upper respiratory tract.

A case of myospherulosis of paranasal sinuses similar in appearance to those recently seen in St. Louis, Missouri, was examined to ascertain the nature of the sac-like structures seen in this disease. The morphologic features of these formations and their positivity with stains for hemoglobin, peroxidase, and lipofuscin strongly suggest that they represent collections of erythrocytes altered by a foreign substance. This interpretation was confirmed by experimental production of these structures by the action of tetracycline ointment on a pure preparation of human erythrocytes.     

Mycoplasma agassizii causes upper respiratory tract disease in the desert tortoise.

The desert tortoise is listed by the United States government as a threatened species in part of its range. A major contributing factor in the decline of this animal has been the presence of an upper respiratory tract disease (URTD) which is characterized by a chronic disease which eventually leads to severe occlusion of the nares with viscous exudate and destruction of the respiratory epithelium. Electron microscopy of infected tissues demonstrated the presence of a mycoplasma-like organism attached to the respiratory surfaces. The mycoplasma was isolated and designated as a new species, with the proposed name Mycoplasma agassizii. The current study was designed to fulfill Koch's postulates and determine if M. agassizii was the etiologic agent of URTD. Clinically healthy animals with known antibody status were infused intranasally with pooled exudate (n = 8) from ill donor animals, with M. agassizii alone (n = 9) or in combination with Pasteurella testudinis (n = 8), with P. testudinis alone (n = 9), or with sterile broth (n = 12). The pooled exudate was culture positive for M. agassizii. Tortoises which received exudate or M. agassizii alone or in conjunction with P. testudinis were significantly more likely to develop clinical disease (P < 0.0004) than animals which received P. testudinis alone or the broth controls. Tortoises demonstrated a strong immune response to M. agassizii, and seroconversion was seen in all groups with clinical disease. M. agassizii was isolated from the upper respiratory tracts of clinically ill animals up to 6 months postinfection. On the basis of the results of these transmission studies, we conclude that M. agassizii is an etiologic agent of URTD in the desert tortoise.     

Diagnosis of IgE-mediated allergy in the upper respiratory tract

A statistical analysis was made of data concerning diagnosis of IgE-mediated allergy in the upper respiratory tract in 292 patients. A study was made of: skin test, total and specific IgE (RAST), X-sinus, red blood investigation, and cytology of nasal smear. It appears that screening for the presence of an IgE-mediated allergy in the upper respiratory tract can be performed efficiently with a limited number of skin tests (rye grass, timothy, birch, house dust mite and cat). In this study a greater number of skin tests (15 instead of 5) yielded little additional information (in 2% of the patients). A rather poor correlation between skin test and RAST was found.     

Co-infection subverts mucosal immunity in the upper respiratory tract

Polymicrobial interactions on mucosal surfaces can influence inflammation, immunity, and disease outcome. Here, we review how host responses to colonization in the upper respiratory tract with the bacterial pathogen Streptococcus pneumoniae can be altered by co-infection. Recent advances provide a mechanistic understanding of how mucosal immunity can be subverted at distinct immunological time-points during pneumococcal colonization by other pathogens such as Haemophilus influenzae, influenza type A and Staphylococcus aureus. These examples use animal models of co-infection to highlight how otherwise effective host responses can be rendered ineffective by co-infection, and vice versa. The complex microbial ecology of mucosal sites must be considered to fully understand how immune responses in a natural setting influence the outcome of host-pathogen interactions.     

Cytokine levels during symptomatic viral upper respiratory tract infection.

BACKGROUND: Previous studies suggest a role for locally produced proinflammatory cytokines in the development and expression of illness during experimental infection with a variety of respiratory viruses. However, most of these studies fail to make comparisons between symptomatic and asymptomatic infected subjects. OBJECTIVE: To compare the pattern of nasal cytokine elaboration in asymptomatic and symptomatic subjects experimentally infected with rhinovirus-39 (RV-39). METHODS: Healthy adults underwent experimental intranasal inoculation with a safety-tested clinical isolate of RV-39. Nasal lavages were collected, nasal symptoms were recorded, and expelled nasal secretions were weighed before and then daily for 6 days after challenge. Nasal lavages were submitted for viral culture and assayed for cytokine protein levels by enzyme-linked immunosorbent assay. RESULTS: Twenty-nine subjects were enrolled in the study. All subjects were infected as evidenced by viral shedding and/or seroconversion. Sixteen subjects were symptomatic and 13 were asymptomatic as evaluated by subject self-report. During infection, significant increases in mean levels of nasal interleukin 6 (IL-6) (P = .01) and IL-1 (P = .02) were observed in symptomatic but not asymptomatic subjects. In symptomatic subjects, these increases were temporally related to the development of nasal symptoms and production of secretions. Mean levels of IL-8, IL-10, and tumor necrosis factor a were not increased in either group during infection. CONCLUSIONS: The results of this study demonstrate elevations in certain locally produced cytokines during symptomatic but not asymptomatic respiratory infection with RV-39. Future studies using selected anticytokine therapies may help elucidate the precise role of cytokines in mediating disease expression.     

Survival of upper respiratory tract bacteria on cotton-wool swabs.

Plain, buffered cotton-wool swabs and albumen-coated cotton-wool swabs were prepared with known numbers of the following: Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, corynebacteria and Escherichia coli. Swabs were plated immediately (0 hours) after loading with a 0.1 ml standardised inoculum; each swab was plated out four times by streaking on both halves of two plates. At 0 hours recovery rates from first platings on solid media ranged from 3.3%-8.9%; from platings 1-4 ranges were 2.5%-5.7%. Both types of swabs gave similar results. The greater the delay in plating swabs at room temperature and 4 degrees C the lower was the recovery rate of H. influenzae and Strep. pneumoniae, though both species survived better on either kind of swab when these were held at 4 degrees C. There was a very small reduction in numbers of Staph. aureus from 24 to 48 hours but the recovery rate of corynebacteria was similar over the 48-hour period, at both room temperature and 4 degrees C. Twenty-four-hour counts of E. coli at room temperature were approximately five times greater than at 0 hours, and at 48 hours colonies were too numerous to count. At 4 degrees C, however, counts of E. coli fell during the 48-hour period.     

Thrombophlebitis and upper respiratory tract virus infection

During an episode of thrombophlebitis, the 72-year-old correspondent came down with a common cold presumably, but not provenly, due to infection by one of the rhinoviruses. During the 96 hr period of coryza, all symptoms of thrombophlebitis vanished completely. There is experimental evidence that rhinovirus infections elicit cytokine production [St?ckl et al. (1999): J Clin Invest 104: 957-965], and that IL-10 can assuage thrombosis in rats [Downing et al. (1998): J Immunol 161: 1471-1476].     

V factor-dependent members of the family Pasteurellaceae in the porcine upper respiratory tract.

A study was performed to obtain a better understanding of the diversity and ecology of members of the family Pasteurellaceae in the porcine respiratory tract. A collection of 132 V factor-dependent strains of Pasteurellaceae selected from porcine field isolates mainly from the respiratory tract were subjected to detailed characterization. In addition to the three hitherto recognized species Actinobacillus pleuropneumoniae, Haemophilus parasuis, and Haemophilus taxon "minor group," three distinct taxa were observed. Some of these taxa, which are provisionally designated taxa D, E, and F, would by traditional criteria be mistaken for H. parasuis but differed by several biochemical characteristics. To study the ecology of the V factor-dependent species, swabs from the nasal and oral cavities of 29 pigs were cultivated on selective and nonselective media. By studying approximately 30 isolates from each sample, the distribution and relative proportion of the individual taxa were determined. A. pleuropneumoniae was detected in samples from the tonsil areas of only two acutely ill animals. H. parasuis was isolated from the nasal cavities of four out of nine healthy pigs but from the oral cavities of only two animals. In contrast, taxon "minor group" and taxa D, E, and F were present in the oral cavities of the majority of pigs but were not detected in samples from their nasal cavities. The results indicate that all the observed V factor-dependent species of Pasteurellaceae except A. pleuropneumoniae, are members of the resident microflora of various mucosal surfaces of the porcine upper respiratory tract.     

Assessing the potential of upper respiratory tract point-of-care testing: a systematic review of the prognostic significance of upper respiratory tract microbes

ObjectivesMicrobial point-of-care testing (POCT) has potential to revolutionize clinical care. Understanding the prognostic value of microbes identified from the upper respiratory tract (a convenient sampling site) is a necessary first step to understand potential for upper respiratory tract POCTs in assisting antimicrobial treatment decisions for respiratory infections (RTIs). The aim was to investigate the relationship between upper respiratory tract microbial detection and disease prognosis, including effects of antimicrobial use.MethodsData sources were the MEDLINE and Embase databases. Study eligibility criteria consisted of quantitative studies reporting microbiological and prognostic data from patients of all age groups presenting with RTI. Patients presenting to healthcare or research settings with RTI participated. Interventions included upper respiratory tract swab. The methods used were systematic review and meta-analysis.ResultsSearches identified 5156 articles, of which 754 were duplicates and 4258 excluded on title or abstract. A total of 144 full texts were screened; 21 articles were retained. Studies reported data for 15 microbes and 26 prognostic measures (390 potential associations). One hundred and seven (27%) associations were investigated statistically, of which 38 (36%) were significant. Most studies reported only prognostic value of test positive results. Meta-analyses suggested hospitalization duration was longer for patients with respiratory syncytial virus than adenovirus and influenza, but significant heterogeneity was observed between studies.ConclusionsA quarter of potential prognostic associations have been investigated. Of these, a third were significant, suggesting considerable potential for POCT. Future research should investigate prognostic value of positive and negative tests, and interactions between test results, use of antimicrobials and microbial resistance.