PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “RESPIRATORY TRACT”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources

Microbial flora variations in the respiratory tract of mice.

A stable microbial system in the respiratory tract acts as an important defense mechanism against pathogenic microorganisms. Perturbations in this system may allow pathogens to establish. In an ecological environment such as the respiratory tract, there are many diverse factors that play a role in the establishment of the indigenous flora. In the present work we studied the normal microbial flora of different areas of the respiratory tract of mice and their evolution from the time the mice were born. Our interest was to know which were the dominant groups of microorganisms in each area, which were the first capable of colonizing and which dominated over time to be used as probiotic microorganisms. Our results show that Gram negative facultatively anaerobic bacilli and strict anaerobic microorganisms were the last ones to appear in the bronchia, while aerobic and Gram positive cocci were present in all the areas of the respiratory tract. The number of facultative aerobes and strict anaerobes were similar in the nasal passage, pharynx instilled and trachea, but lower in bronchia. The dominant species were Streptococcus viridans and Staphylococcus saprophyticcus, followed by S. epidermidis, Lactobacilli and S. cohnii I which were present on every studied days but at different proportions. This paper is the first part of a research topic investigating the protective effect of the indigenous flora against pathogens using the mice as an experimental model.

Animals↗

Effect of procalcitonin-guided treatment on antibiotic use and outcome in lower respiratory tract infections: cluster-randomised, single-blinded intervention trial.

BACKGROUND: Lower respiratory tract infections are often treated with antibiotics without evidence of clinically relevant bacterial disease. Serum calcitonin precursor concentrations, including procalcitonin, are raised in bacterial infections. We aimed to assess a procalcitonin-based therapeutic strategy to reduce antibiotic use in lower respiratory tract infections with a new rapid and sensitive assay. METHODS: 243 patients admitted with suspected lower respiratory tract infections were randomly assigned standard care (standard group; n=119) or procalcitonin-guided treatment (procalcitonin group; n=124). On the basis of serum procalcitonin concentrations, use of antibiotics was more or less discouraged (<0.1 microg/L or <0.25 microg/L) or encouraged (> or =0.5 microg/L or > or =0.25 microg/L), respectively. Re-evaluation was possible after 6-24 h in both groups. Primary endpoint was use of antibiotics and analysis was by intention to treat. FINDINGS: Final diagnoses were pneumonia (n=87; 36%), acute exacerbation of chronic obstructive pulmonary disease (60; 25%), acute bronchitis (59; 24%), asthma (13; 5%), and other respiratory affections (24; 10%). Serological evidence of viral infection was recorded in 141 of 175 tested patients (81%). Bacterial cultures were positive from sputum in 51 (21%) and from blood in 16 (7%). In the procalcitonin group, the adjusted relative risk of antibiotic exposure was 0.49 (95% CI 0.44-0.55; p<0.0001) compared with the standard group. Antibiotic use was significantly reduced in all diagnostic subgroups. Clinical and laboratory outcome was similar in both groups and favourable in 235 (97%). INTERPRETATION: Procalcitonin guidance substantially reduced antibiotic use in lower respiratory tract infections. Withholding antimicrobial treatment did not compromise outcome. In view of the current overuse of antimicrobial therapy in often self-limiting acute respiratory tract infections, treatment based on procalcitonin measurement could have important clinical and financial implications.

Acute Disease↗

Management variables associated with high mortality rates attributable to respiratory tract problems in female calves prior to weaning.

OBJECTIVE: To identify risk factors associated with high mortality rates attributable to respiratory tract problems in female calves prior to weaning. DESIGN: Cross-sectional national survey. SAMPLE POPULATION: 1,685 dairies. PROCEDURE: Dairies that had > or = 3 female calves that were born by a herd member or purchased during a 3-month period were classified into operations with high or low mortality rates attributable to respiratory tract problems in female calves prior to weaning. Step-wise logistic regression was used to identify management practices associated with high mortality rates caused by respiratory tract problems. RESULTS: 1,363 of 47,057 (2.9%) calves died of respiratory tract problems during a 3-month period. Management variables associated with high mortality rates caused by respiratory tract problems were housing of > or = 7 calves in a group and rolling herd average for milk production of < or = 9,072 kg. Also, dairies located in the West or Southeast had higher mortality rates. CLINICAL IMPLICATIONS: Dairy operators that house calves in large groups prior to weaning may need to pay close attention to respiratory tract illness in their calves. Herds with high milk production have lower mortality from respiratory tract illness than herds with low milk production. Dairies in the West and Southeast have higher mortality attributable to respiratory tract problems than dairies in other regions of the country.

Animal Husbandry↗

[Analysis of possible causes of recurrent respiratory tract infections in children from Lodz, Poland].

Recurrent respiratory tract infections are responsible for about 85% of all diseases in childhood. Early diagnosis helps to prevent infections and start the appropriate treatment, what in turn prevents lungs from irreversible damage. The aim of this study was the analysis of possible causes of recurrent respiratory tract infections in children in Lodz region. We analyzed cases of 6335 children with recurrent respiratory tract infections, age 3 months to 17 years, referred to the clinic in our hospital by family doctors from 2000 to 2002. Among all children, 41.5% were diagnosed with allergy, 26.9% of patients had persistent Mycoplasma pneumoniae and 1.4% Bordetella pertussis infection. Very disturbing was the fact of very late cystic fibrosis diagnose at the age of 7,11 and 16. Congenital immune disorders were diagnosed late in five children at the age of 6,7,8,9,11, what delayed appropriate therapy and early prevention of infections.

Adolescent↗

Rhinoscleroma of the lower respiratory tract.

Rhinoscleroma is a chronic granulomatous disease of the respiratory tract endemic to Eastern Europe and Central America which is being recognized with increasing frequency in other countries, including the United States. It was initially described as a lesion of the nose and upper respiratory tract, but is now known to involve the larynx, trachea and bronchi as well to cause slowly progressive asphyxia. Eleven cases of rhinoscleroma with varying degrees of involvement of the lower respiratory tract (larynx, trachea and bronchi) are presented. Present day treatment is both medical, consisting primarily of streptomycin and tetracycline, and endoscopic dilatation. Prolonged medication with careful dose control is necessary. Lower respiratory tract involvement should be considered in patients with chronic destructive granulomatous nasal pathology. This should be especially emphasized if they have an Eastern European or Central American background, or have travelled in these areas in which rhinoscleroma is endemic.

Adult↗

Multicenter trial of cefpodoxime proxetil vs. amoxicillin-clavulanate in acute lower respiratory tract infections in childhood. International Study Group.

Acute lower respiratory tract infections in children are a worldwide public health problem, with an estimated 4 million potentially preventable deaths every year. Until recently, penicillin and related drugs were the treatment of choice for empiric therapy of paediatric lower respiratory tract infections. However, concerns over the emergence of penicillin-resistant strains of Streptococcus pneumoniae and beta-lactamase-producing strains of Haemophilus influenzae and Moraxella catarrhalis have led physicians to turn increasingly towards alternatives, such as the third generation cephalosporins. The oral extended spectrum cephalosporin cefpodoxime proxetil is highly active against the bacterial pathogens commonly associated with childhood lower respiratory tract infections. In order to evaluate its clinical efficacy in children with acute febrile lower respiratory tract infections, an international, multicenter, comparative, randomized open study was conducted in children ages 3 months to 11.5 years. Of 348 cases enrolled, 234 were randomized to cefpodoxime proxetil (8 mg/kg/day twice daily) and 114 to amoxicilin/clavanulate (amoxicillin 40 mg/kg/day 3 times a day). The duration of treatment was 10 days. Pretreatment diagnosis was pneumonia in 292 patients, bronchiolitis in 19 patients and acute bronchitis in 37 patients. Pathogens isolated from 59 cases included H. influenzae (47.5%), S. pneumoniae (23.7%), M. catarrhalis (11.9%) and Haemophilus parainfluenzae (6.8%). Clinical efficacy was evaluable in 278 children at the end of treatment when 95.2% of patients in the cefpodoxime proxetil group and 96.7% of patients in the amoxicillin/clavanulate group showed a satisfactory clinical response (cured or improved). The improvement was sustained at the follow-up visit, 10 to 20 days after completion of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Managing acute lower respiratory tract infections in an era of antibacterial resistance.

Respiratory tract infections account for more than 116 million office visits and an estimated 3 million visits to hospital EDs annually. Patients presenting at EDs with symptoms suggestive of lower respiratory tract infections of suspected bacterial etiology are often severely ill, thus requiring a rapid presumptive diagnosis and empiric antimicrobial treatment. Traditionally, clinicians have relied on beta-lactam or macrolide antibiotics to manage community-acquired lower respiratory tract infections. However, the emerging resistance of Streptococcus pneumoniae to beta-lactams and/or macrolides may affect the clinical efficacy of these agents. Inappropriate use of antibiotics and use of agents with an overly broad spectrum of antimicrobial activity have contributed to the emergence of antibiotic resistance. When treating respiratory infections, clinicians need to prescribe antimicrobial agents only for those individuals with infections of suspected bacterial etiology; to select agents with a targeted spectrum of activity that ensures coverage against typical S pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis strains, including antibiotic-resistant strains and atypical pathogens; and to consider agents with specific chemical properties that limit the development of antimicrobial resistance and that achieve concentrations at sites of infection that exceed those required for bactericidal activity. Newer classes of antimicrobial agents, such as the oxazolidinones and ketolides, will likely play a significant role in this era of antimicrobial resistance.

Acute Disease↗

[Antibiotic prescribing patterns for pediatric inpatients with acute respiratory tract infection].

BACKGROUND: Children with acute respiratory tract infection (ARTI) represent an important target group for efforts aimed at reducing unnecessary antibiotic use. OBJECTIVE: To present the epidemiological data and evaluate the effect of clinical, laboratory, radiological and microbiological data on the decision to prescribe antibiotics to pediatric patients with ARTI as well as to seek criteria that would justify antibiotic use. PATIENTS AND METHODS: A retrospective review was made of the clinical histories of 147 previously healthy children, consecutively admitted to our hospital with ARTI for 1 year (May 1996-April 1997). Patients were divided in two groups: those not treated with antibiotics (n = 92) and those treated (n = 55). Data from the two groups were compared with a statistical computer program (R-Sigma). RESULTS: Of the 147 patients studied, mean age was 2.5 years (range 0-14 years) and 85 (58%) males. One-hundred-and-five patients (72%) had previously been attended to in the emergency room, and 45 patients (30%) had been treated with antibiotics. Upper respiratory tract infection was diagnosed in 81 patients (54%), bronchitis in 28 (18%), bronchiolitis in 23 (15%) and pneumonia in 15 (10%). Ninety-seven patients (66%) had viral infection and only two (1%) had bacterial infection. Syncytial respiratory virus was isolated in 41 patients (28%) and adenovirus in 30 (20%). In the untreated group, the longer duration of symptoms before admission, lymphocytosis, clinical diagnosis of bronchiolitis and normal thorax X-ray, were statistically significant. In the treated group, fever, leukocytosis, neutrophilia and a diagnosis of pneumonia were statistically significant. Length of stay was longer in this group than in the untreated group. CONCLUSIONS: It is difficult to prescribe antibiotics on the basis of bacteriologic data. Laboratory, analytic and radiological data can be helpful in the rational use of antibiotics.

Acute Disease↗

Squamous cell carcinoma of the esophagus infiltrating the respiratory tract is less sensitive to preoperative concurrent radiation and chemotherapy.

BACKGROUND: The prognosis of upper thoracic esophageal cancer is poor when compared with middle and lower thoracic esophageal cancer because the tumor easily infiltrates the respiratory tract and surgical en-bloc resection is difficult. Recently, preoperative chemoradiation therapy has been shown to lead to down-staging of the disease and improve prognosis. But the benefit of this therapy for tumors infiltrating the respiratory tract remains unknown. STUDY DESIGN: Fifty-six patients with thoracic esophageal cancer infiltrating neighboring organs, but with no hematogeneous metastasis, were given preoperative concurrent chemotherapy (5-fluorouracil and cisplatin) and radiation (40 Gy) therapy. When a clinical response was observed, making a curative resection potentially possible, patients were scheduled for esophagectomy with extended lymphadenectomy. Patient prognosis with respect to the organs infiltrated by the tumors was estimated by calculating survival curves using the Kaplan-Meier method and comparing the curves by the log-rank test. RESULTS: The prognosis was significantly poorer for patients with tumors infiltrating the respiratory tract (T) or aorta plus respiratory tract (A + T) than for patients with tumors infiltrating the aorta alone (A) or other organs (Oth) (p < 0.05 for Oth versus T; p < 0.05 for Oth versus A + T; p < 0.0001 for A versus T; p < 0.0001 for A versus A + T by log-rank test). Patients positive for respiratory tract invasion (T, T + A), compared with those negative for respiratory tract invasion (A, Oth), showed a poorer clinical response to chemoradiation (3.0%, 45.5%, 39.4%, and 9.1% versus 4.3%, 82.6%, 4.3%, and 8.7% in complete response (CR), partial response (PR), nonresponse (NC) and progressive disease (PD), respectively, p = 0.0156) and surgical resectability (36.4% vs. 87.0%, p = 0.0003). Histologic effectiveness (8.3%, 50.0%, and 41.7% versus 25.0%, 70.0%, and 5.0% in grade 3, grade 2, and grade 1, respectively, for patients with respiratory tract invasion versus those without it, p = 0.0189) and histologic stages (8.3%, 8.3%, 8.3%, 8.3%, 25.0%, and 41.7% versus 20.0%, 0%, 15.0%, 25.0%, 40.0%, and 0% in pathologic CR, stage I, stage IIA, stage IIB, stage III, and stage IV, respectively, for patients with respiratory tract invasion versus those without it, p = 0.0496) were significantly better in patients negative for respiratory tract invasion; the percentages of patients with lymph node metastasis did not differ significantly between the two groups. Comparison of the recurrence patterns showed that local failure was most common in patients with respiratory tract invasion, and distant failure was the leading cause of recurrence in patients without it. CONCLUSIONS: Because the prognosis of patients with thoracic esophageal cancer infiltrating the respiratory tract is extremely poor, partially because of the low local effectiveness of preoperative concurrent chemotherapy and radiation therapy, caution is needed when deciding on salvage surgery.

Adult↗

[Serum levels and sputum levels of cefmenoxime in respiratory tract infections].

In 11 patients with respiratory tract infections, the concentrations of cefmenoxime (CMX) in serum and sputum after 1 hour intravenous administration of 2 g of CMX were investigated. The peak serum level of CMX was 102.2 +/- 11.4 micrograms/ml after 1 hour drip infusion, then declined and was 3.51 +/- 0.55 micrograms/ml after 5 hours. Sputum level of CMX was lower than serum level but it was able to cover enough for MIC of Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Streptococcus pneumoniae and the peak sputum level of CMX was 0.77 +/- 0.17 micrograms/g after from 2 hours to 4 hours. Among the 11 patients with respiratory tract infections, 2 patients showed excellent, 6 patients good, 3 patients poor results (isolated organisms of sputum were normal flora) and no side effects observed.

Adult↗

Comparative In Vitro Activities of Moxifloxacin (Bay 12-8039) and Other Antimicrobial Agents Against Respiratory Tract Pathogens in Brazil.

Clinical isolates of respiratory tract pathogens were susceptibility tested against six different antimicrobial agents. The in vitro activity of moxifloxacin was compared with that of levofloxacin, cefaclor, amoxicillin-clavulanate acid, azithromycin and trimethoprim-sulfamethoxazole against 111 isolates, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and other species isolated from respiratory tract infections. All isolates were susceptible to moxifloxacin, except for two isolates of Pseudomonas aeruginosa which showed intermediate-resistance (MIC=6µg/mL), and one isolate of Escherichia coli which showed resistance (MIC>32µg/mL). Only moxifloxacin and amoxicillin-clavulanic acid were active against 100% of S. pneumoniae isolates at the suceptible breakpoint (MIC90, 0.25 µg/mL and 0.064 µg/mL respectively). The rank order of the activity among this group of drugs against S. pneumoniae was as follows (% of susceptibility): moxifloxacin = amoxicillin-clavulanic acid (100%) > levofloxacin (97%) > cefaclor (71%) > trimethoprim-sulfamethoxazole (54%) > azithromycin (53%). Except for trimethoprim-sulfamethoxazole, all antimicrobial agents were 100% active against H. influenzae and M. catarrhalis. The fluoroquinolones, moxifloxacin and levofloxacin, were the most potent compounds against these pathogens (MIC(90) 0.032 0.19 µg/mL). These in vitro susceptibility testing data of moxifloxacin support the view that this fluoroquinolone will have an important therapeutic role in the treatment of respiratory tract diseases.

Journal Article↗

Surveillance of resistance in bacteria causing community-acquired respiratory tract infections.

Bacterial resistance to antibiotics in community-acquired respiratory tract infections is a serious problem and is increasing in prevalence world-wide at an alarming rate. Streptococcus pneumoniae, one of the main organisms implicated in respiratory tract infections, has developed multiple resistance mechanisms to combat the effects of most commonly used classes of antibiotics, particularly the beta-lactams (penicillin, aminopenicillins and cephalosporins) and macrolides. Furthermore, multidrug-resistant strains of S. pneumoniae have spread to all regions of the world, often via resistant genetic clones. A similar spread of resistance has been reported for other major respiratory tract pathogens, including Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pyogenes. To develop and support resistance control strategies it is imperative to obtain accurate data on the prevalence, geographic distribution and antibiotic susceptibility of respiratory tract pathogens and how this relates to antibiotic prescribing patterns. In recent years, significant progress has been made in developing longitudinal national and international surveillance programs to monitor antibiotic resistance, such that the prevalence of resistance and underlying trends over time are now well documented for most parts of Europe, and many parts of Asia and the Americas. However, resistance surveillance data from parts of the developing world (regions of Central America, Africa, Asia and Central/Eastern Europe) remain poor. The quantity and quality of surveillance data is very heterogeneous; thus there is a clear need to standardize or validate the data collection, analysis and interpretative criteria used across studies. If disseminated effectively these data can be used to guide empiric antibiotic therapy, and to support-and monitor the impact of-interventions on antibiotic resistance.

Africa↗

Serological evidence for the association of bovine respiratory syncytial virus with respiratory tract disease in Alabama cattle.

A serological investigation for neutralizing antibody to bovine respiratory syncytial virus (BRSV) was conducted using an antigenically related human strain of respiratory syncytial virus. Results demonstrated the effectiveness of the procedure. Sixty-seven percent of healthy, adult cattle tested were found to have antibody to BRSV. Calves in several herds were exposed to conditions to encourage development of respiratory tract disease. In three herds in which respiratory tract disease subsequently developed, the incidence of BRSV seroconversions approached 100%. In a herd in which no respiratory tract disease was detected, BRSV seroconversions indicated a high incidence of subclinical infections. It was concluded that, in this country as has been shown in others, BRSV is probably a significant pathogen of the bovine respiratory tract.

Alabama↗

Immune responses to mycoplasma infections of the respiratory tract.

Mycoplasmas are capable of causing respiratory disease in a number of species of animals. The pathogenicity of the mycoplasma species ranges from those that cause major disease outbreaks and economic loss to what might be considered the more highly evolved and successful parasites at the other end of the spectrum that survive for long periods in the host without being recognised and evicted. This prolonged colonisation of mucous membranes which is typical of many mycoplasmas is related to certain unique features of the mycoplasma and its interaction with the hosts immune system. An initial step in infection is the attachment of the mycoplasma to the epithelial lining of the respiratory tract. Lack of cell wall confers plasticity and may engender the intimate association of mycoplasma and host cell that has been noted. This in turn may favour persistence of the extracellular parasite. Before the specific immune response is produced avoidance of the non-specific immune mechanisms would clearly aid survival. Both passive (capsules) and active (toxic effects) mechanisms of avoiding phagocytosis have been proposed. Both humoral and cell mediated responses are generated by mycoplasma infections. The serum antibody response follows the usual course IgM, G and A. The indications of cell mediated immunity that have been reported include; delayed type hypersensitivity reactions, lymphocyte transformation responses and inhibition of macrophage migration. The concept that the pathological lesions are in a large part due to host reactivity is well accepted. The lung lesions may contain infiltrating and dividing lymphocytes some of which are producing specific antibody. Evidence for the lung lesion in some animals being partly due to the hosts cell mediated response has also been produced. The local immune response appears to be of greater relevance to immunity to infection than the systemic response, in general the association between local antibody and immunity is much better than for serum antibody. Of particular note is the high contribution of local IgG production, particularly in the lower respiratory tract. Attempts are now being made to use this increased understanding to produce effective killed vaccines that produce immune responses in the lung. Such studies will hopefully lead to the development of 'killed' vaccines that are effective. It can be urged that mycoplasmas would be less pathogenic if they did not produce an inflammatory response and some species have been shown to have an immunosuppressive effect. Such a property could affect the lesion, and hence pathogenicity, and also aid mycoplasma persistence.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Antibacterial mechanisms of the lower respiratory tract. I. Immunoglobulin synthesis and secretion.

Immunoglobulin synthesis and secretion have been studied in the rabbit lower respiratory tract, both in the normal state and after infection with Diplococcus pneumoniae or Listeria monocytogenes. In vitro synthesis of immunoglobulin and specific antibody was assessed by incorporation of 14C-labeled amino acids into protein. Lower respiratory tract secretions and serum were analyzed for immunoglobulin and antibody against the infecting organism. Normal respiratory tract produced small quantities of immunoglobulin, most of which was IgG. After bacterial infection of the lower respiratory tract, there was a marked increase in local synthesis of immunoglobulin, especially IgG. Specific antibody of IgG class was produced in all lungs infected with listeria by the 11th day, and in lungs infected with pneumococcus by the 8th day. Secretions from all normal and infected lower respiratory tracts contained IgA and IgG. The IgA to IgG ratios in secretions of normal animals, and animals infected with listeria or pneumococcus, were 2.3, 2.5, and 2.6, respectively. Sera of animals infected with L. monocytogenes contained specific antibody of IgG class but lacked IgA antibody, whereas secretions had both IgA and IgG class antibody against listeria. Similarly, sera of animals infected with D. pneumoniae had IgG class antibody but no IgA antibody, whereas only IgA antibody was found in secretions. The evidence that locally synthesized immunoglobulin (especially IgA), including specific antibody, is secreted into the lower respiratory tract lumen is discussed. Further definition of the role of "local" antibacterial antibody in the respiratory tract is of considerable importance.

Animals↗

[Influence of lactobacterin on the upper respiratory tract microflora of subjects with microflora disorders].

High respiratory tract microflora recovery has been revealed in human subjects treated perorally with commercial Lactobacterinum. In most of the participants in the study, different (up to epidemically significant) values of disbiotic shifts including persistence of conventional pathogens (enterobacteria) and pathogenic staphylococci in high respiratory tract mucosa as well as nasopharyngeal lactoflora deficiency were observed in the pretreatment period. Significant, in the order of one to four, decreases in pathogenic microflora count up to complete elimination were accompanied by lactoflora restoration in a part of the subjects after treatment. Hence, Lactobacterinum seems to be a perspective means for correcting and optimizing the high respiratory tract microflora, especially in contingents subjected to the environmental factors with a high risk of disbiotic disorders.

Anti-Bacterial Agents↗

Epidemiology of acute respiratory tract infections among Guatemalan ambulatory preschool children.

Acute respiratory tract infections (ARI) were studied during a 2-year period in 521 preschool children living in a marginal area of Guatemala City. There were 3,646 episodes of ARI detected during 26,329 child-weeks at risk, for an incidence of 14 per 100 child-weeks or 7.2 episodes per child per year. The median duration of ARI episodes was 11 days. The highest incidence of ARI was observed in children 6-23 months old. Boys had more respiratory tract illnesses than did girls; the presence of a cigarette smoker in the household was associated with higher morbidity. Acute lower respiratory tract illnesses (ALRI) were more common among younger infants 0-5 months old, with nutritional status having no apparent effect. Parental formal education and crowding in households were found to be directly related to the incidence of ALRI. In general, ARI morbidity interfered with appropriate physical growth.

Acute Disease↗

Correlation between Branhamella catarrhalis adherence to oropharyngeal cells and seasonal incidence of lower respiratory tract infections.

Bacterial colonization of the oropharynx is the initial event in most lower respiratory tract infections. To study the role of bacterial adherence in lower respiratory tract infections caused by Branhamella catarrhalis (B. catarrhalis) in winter, in vitro adherence assays of the organism to human oropharyngeal cells were carried out in winter, spring, summer and autumn. A total of 57 adults of both sexes were studied from January to December 1985. Forty eight persons of 57 had chronic pulmonary diseases and the remaining 9 persons had other clinical entities and served as the control group. Predominance of lower respiratory tract infections caused by B. catarrhalis with high adherence rate was observed in winter. Adherence activity was moderate in spring and autumn and low in summer and accompanied by a similar incidence of lower respiratory tract infections with this bacteria. In addition, similar results were found in patients in whom investigations were done successively in the above four seasons. Bacterial adherence activity to cells however, was weak in winter in the control group. These results indicate that seasonal variation plays a significant role in the ability of B. catarrhalis to adhere to oropharyngeal cells. This is an important pathogenic factor correlated with the incidence of lower-respiratory tract infections in these patients.

Adult↗