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Upper respiratory tract infections in general practice: diagnosis, antibiotic prescribing, duration of symptoms and use of diagnostic tests.

A diagnosis/antibiotic prescribing study was performed in 5 counties in Sweden for 1 week in November 2000. As part of this study, the characteristics and clinical management of patients with upper respiratory tract infections (n = 2899) in primary care were analyzed. Almost half of the patients were aged < 15 y and one-fifth of the patients consulted out of hours. Of all patients seeking primary care for upper respiratory tract infections, 56.0% were prescribed an antibiotic. Almost all patients who were given the diagnoses streptococcal tonsillitis, acute otitis media or acute sinusitis were prescribed antibiotics, compared to 10% of patients with common cold or acute pharyngitis. The most frequently prescribed antibiotic was penicillin V (79.2%) and this was even more pronounced out of hours, when the diagnoses otitis media and streptococcal tonsillitis were more frequently used. In patients with common cold and acute pharyngitis, the percentage who received antibiotics increased with increasing length of symptoms and increasing CRP levels. In patients with acute pharyngitis or streptococcal tonsillitis, antibiotics were prescribed less frequently provided streptococcal tests were performed. The management of patients with upper respiratory tract infections in general practice seems to be in good agreement with current Swedish guidelines. However, the study indicates some areas for improvement. The diagnosis of acute sinusitis seems to have been overestimated and used only to justify antibiotic treatment.

Acute Disease↗

Isolation of mycoplasma species from the lower respiratory tract of healthy cattle and cattle with respiratory disease in Belgium.

Between 1997 and 2000, a total of 150 healthy cattle and 238 animals with respiratory disease were examined for six Mycoplasma species. Attempts were made to detect Mycoplasma canis, Mycoplasma dispar and Ureaplasma diversum in calves with recurrent disease, and all three of these species were identified in calves with recurrent disease and in healthy lungs. In healthy calves, 84 per cent of bronchoalveolar lavage fluids were mycoplasma free; when cultures were positive, Mycoplasma bovirhinis was the only species isolated. Mycoplasmas were isolated from 78 per cent of animals suffering recurrent respiratory disease and from 65 per cent of acute respiratory cases. Mycoplasma bovis was isolated from bronchoalveolar lavages from 35 per cent of calves suffering recurrent respiratory disease, and from 50 per cent of acute cases, and from 20 per cent of pneumonic cases examined postmortem. M bovis was associated with other Mycoplasma species in 44 per cent of cases. M dispar was also isolated from 45.5 per cent of calves suffering recurrent respiratory disease, often in association with M bovis. M canis was identified for the first time in diseased Belgian cattle. Other mycoplasmas, including Mycoplasma arginini, Mycoplasma alkalescens and U diversum, were isolated less frequently. Associations between mycoplasmas and other pathogens were often observed. Among lungs infected with Pasteurella and/or Mannheimia species, more than 50 per cent were mixed infections with M bovis.

Acute Disease↗

Seasonal pattern in childhood viral lower respiratory tract infections in Melbourne.

Respiratory syncytial virus and parainfluenza viruses are the major pathogens in acute lower respiratory infection in infants and younger children. They show distinct seasonal patterns. An annual epidemic of respiratory syncytial virus infection is seen in Melbourne and this coincides with the coldest months of the year. Parainfluenza virus Type 1, the most frequent cause of laryngotracheobronchitis, occurs as an autumn epidemic every second year. Parainfluenza virus Types 2 and 3 are present most years and do not show a clear seasonal pattern.

Acute Disease↗

[Virus infections of the respiratory tract of dogs].

Canine respiratory infections are reviewed with special reference to those caused by agents, other than distemper and canine infectious hepatitis viruses, but producing, both naturally and experimentally, the so-called distemper-like syndromes. The existence of canine infections caused by Adeno-Herpes-,Reo-, and Paramyxoviruses is reported, and for each of these agents the physicochemical characteristics, pathogenicity for dogs and other animal species, incidence and methods of dissemination are described. As regrads the prophylaxis of the individual infections that appear particularly widespread in kennels, the possible availability in the short or long term of immunizing preparations is indicated, along with the basic measures of hygiene for their control. The availability of immunizing preparations depends, firstly, on a more exact knowledge of the aetiological agents involved in canine respiratory conditions, and secondly, on a precise determination of the mechanisms by which the immune reactions are elicited. It is, however, obvious that the incidence of respiratory infections could be substantially reduced by the application of all the hygienic measures that can ensure a high environmental standard for the animals.

Adenoviridae↗

Acute infections of the respiratory tract in children.

Although respiratory infections are the commonest childhood diseases, they remain some of the most poorly understood. With identification of viruses as the causes of most respiratory diseases as well as controlled epidemiological studies, the understanding to acute respiratory infections is gradually increasing. Problems still exist, however, in clinically differentiating bacterial from viral infections and in evaluation the host-organism interaction.

Acute Disease↗

[Respiratory tract mycotic infection in phthisiological practice: species composition and susceptibility of the Candida clinical isolates to antifungal agents].

The results of the laboratory diagnosis of respiratory tract candidiasis in patients with tuberculosis of the respiratory organs within 2-year observation in a tuberculosis clinic were generalized. The species composition of 327 isolates of the pathogens of the respiratory tract mycotic infection and the frequency of their detection in the specimens of various clinical material from patients with pulmonary tuberculosis were determined. The data on the resistance of the Candida spp. isolates to 6 antifungal drugs are presented. The number of the strains resistant to azol drugs (intraconazol and fluconazol) amounted to 10% of the total number of the Candida spp. isolates.

Antifungal Agents↗

Procalcitonin as a diagnostic tool in lower respiratory tract infections and tuberculosis.

The diagnostic significance of procalcitonin concentrations in lower respiratory tract infections and tuberculosis is not known. A prospective analysis was, therefore, performed in patients with acute exacerbation of chronic bronchitis (AECB), community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and tuberculosis and their procalcitonin levels compared with those of patients with noninfectious lung diseases (controls). In addition, standard inflammatory parameter data were collected. A prospective clinical study was performed with four different groups of patients and a control group that consisted of patients with noninfectious lung diseases. A total of 129 patients were included: 25 with HAP, 26 CAP, 26 AECB, 27 tuberculosis, and 25 controls. C-reactive protein level, blood cell counts and procalcitonin concentration were evaluated on the first day after onset of clinical and inflammatory symptoms prior to treatment. The median procalcitonin concentrations in HAP, CAP, AECB and tuberculosis were not elevated in relation to the cut-off level of 0.5 ng x mL(-1). In the HAP group, in four of five patients who subsequently died, procalcitonin concentrations of >0.5 ng x mL(-1) were found. In acute lower respiratory infections, such as HAP, CAP and AECB, significantly elevated levels were found in comparison to the control group, but below the usual cut-off level. No differences were observed between tuberculosis and the control group. Relative to the current cut-off level of 0.5 ng x mL(-1), procalcitonin concentration is not a useful parameter for diagnosis of lower respiratory tract infections. However, compared to the control group, there were significantly elevated levels in patients with hospital-acquired pneumonia, community-acquired pneumonia and acute exacerbation of chronic bronchitis below the current cut-off level, which should be further investigated.

Acute Disease↗

Microbiological considerations of the etiological agents of lower respiratory tract infections.

One hundred eight-four sputum specimens from the same number of patients with lower respiratory tract infections were examined to determine the bacterial count and the relationship between the microorganisms isolated and the presumptive pathology. The sputa were subdivided into three groups; "high probability", "low probability", and "contaminated sputa", following the criteria of the microscopic readings: sputum with more than 25 white cells and low numbers of squamous epithelial cells represents true lower respiratory tract infections (high probability); those with fewer than 25 white cells represent non-bacterial infections or non-infected sputa (low probability) while sputa with more than 25 squamous cells per field represent contaminated specimens (contaminated sputa). Statistical analysis was carried out to correlate these data. Haemophilus influenzae, Haemophilus parainfluenzae, Streptococcus pneumoniae, and Streptococcus pyogenes showed significant differences in the three groups considered.

Gram-Negative Bacteria↗

Reduction in antibiotic prescribing for respiratory tract infections is needed!

In general practice, approximately 25% of consultations are related to infectious diseases. The emergence and spread of resistant bacteria are related to antibiotic use on an individual and on a community level. Antibiotic prescribing differs profoundly from one European country to the next, though there is no evidence of differences in the prevalence of infectious diseases. Most respiratory tract infections are self-limiting conditions, and recent evidence shows that antibiotics only slightly modify the course of most respiratory tract infections. The general practitioner should focus on patients with more severe symptoms who might benefit more from antibiotic treatment. In general, antibiotics should be prescribed for acute pneumonia. In addition, we may offer antibiotics to a selected group of patients with more severe symptoms of maxillary sinusitis, pharyngotonsillitis and acute exacerbation of chronic obstructive pulmonary disease/chronic bronchitis. In the diagnostic procedure, rapid tests of Streptococcus pyogenus and C-reactive protein may be valuable in carefully selected cases. Penicillins (penicillin V, amoxycillin) should be the first choice in most respiratory tract infections. Larger studies in general practice are needed to analyse the impact of antibiotic prescribing on morbidity, the occurrence of rare complications and spread of resistance. The greatest challenge will be to implement current knowledge in daily praxis.

Anti-Bacterial Agents↗

Development and testing of a unique strain of Pasteurella haemolytica for use in studies on colonization of the respiratory tract of cattle.

OBJECTIVE: To develop a unique strain of Pasteurella haemolytica, selectable from nasopharyngeal respiratory tract secretions, that retains the ability to efficiently colonize the respiratory tract of calves. ANIMALS: 26 calves that each weighed approximately 200 kg. PROCEDURE: Rifampicin-resistant mutants of P haemolytica were developed and tested for in vitro growth rate and leukotoxin production. After instillation into the tonsils of calves, an isolate that was efficient at colonizing was selected and transformed, using electroporation, with a 4.2-kilobase (kb) plasmid encoding for streptomycin resistance. This isolate was instilled into the tonsils of 4 of 14 commingled calves to examine transmission of organisms. Nasal secretion and tonsil wash specimens were collected, cultured, and examined for P haemolytica. Serum antibody concentration was measured by means of indirect hemagglutination. RESULTS: Selected P haemolytica organisms colonized the tonsils and nasal passages for more than 2 weeks. Exposed calves and contact calves shed the organism, which was recovered from specimens of nasal secretions and tonsil washes. The 4.2-kb plasmid was lost during in vivo colonization. CONCLUSIONS AND CLINICAL RELEVANCE: The selected rifampicin-resistant P haemolytica organism colonized tonsils and nasal passages in a manner similar to the wild-type organisms. Selective media suppressed other bacterial flora to the extent that a single colony-forming unit was detectable from 200 microl of specimen, a 100-fold improvement in detection sensitivity. The selectable strain spread rapidly among commingled calves. A 4.2-kb plasmid marker was unstable when P haemolytica replicated in vivo.

Animals↗

Frequency and severity of apnoea in lower respiratory tract infection in infancy.

Twenty four hour recordings of heart rate and respiration were made on 60 infants with lower respiratory tract infection (LRTI) during the acute phase of the illness, on 20 infants with upper respiratory tract infection (URTI) and on 21 control infants. Infants with LRTI and URTI had more apnoeic episodes of longer than 10 seconds compared with controls. The length of apnoeic episodes was greatest in the LRTI group but their frequency decreased with age. In both the LRTI and URTI groups apnoea was associated with bradycardia but the LRTI group also suffered an appreciable number of episodes of bradycardia without apnoea.

Age Factors↗

Chimeric influenza virus replicating predominantly in the murine upper respiratory tract induces local immune responses against human immunodeficiency virus type 1 in the genital tract.

Previously, a mucosal model of immunization against human immunodeficiency virus type 1 (HIV-1) was established by using influenza virus as a vector for the neutralizing gp41 epitope ELDKWA. Whether replication of this chimeric influenza virus in the upper respiratory tract of mice is sufficient for inducing mucosal immune responses in the genital tract was investigated. An immunization strategy was established that permits the virus to replicate in the murine upper respiratory tracts but not in the lungs. Intranasal application of the chimeric virus induced HIV-1-specific antibodies in sera and genital tract. In addition, chimeric virus-specific antibody-secreting cells were detected in lymphocyte populations obtained from lungs, spleens, and urogenital tracts. These results indicate that replication of the chimeric influenza/ELDKWA virus in the upper respiratory tract is sufficient to induce systemic immune responses as well as local immune responses in the genital tract.

AIDS Vaccines↗

Exhaled carbon monoxide in patients with lower respiratory tract infection.

The concentration of carbon monoxide (CO) in exhaled air is increased in patients with asthma, bronchiectasis and upper respiratory tract viral infections. However there is no information about the level of CO in patients with lower respiratory tract infection. We studied a group of 35 patients (22 males) aged 45 +/- 3 (SEM) years with cough productive of purulent phlegm and pyrexia in a general practice setting. All were non-smokers or ex-smokers and none had a previous history of respiratory problems or diabetes. We measured CO level in exhaled air before and after a course of antibiotics. Therapy was deemed successful when patient no longer complained of cough productive of purulent phlegm. Twenty-eight of 35 patients had elevated CO level at their initial visit. Twenty-two out of 35 patients reported clinical improvement after antibiotic treatment and this was associated with a fall in exhaled CO level from 5.2 +/- 0.5 ppm to 2.3 +/- 0.3 ppm (P < 0.0001). We suggest that simple CO measurements in exhaled air can detect the inflammatory process within the airways caused by infection and that a repeat measurement can be used to assess the nature of inflammation.

Adult↗

Eosinophil-mediated injury to lung parenchymal cells and interstitial matrix. A possible role for eosinophils in chronic inflammatory disorders of the lower respiratory tract.

Eosinophils are a common component of the inflammation of the lower respiratory tract that characterizes the interstitial lung disorders. Bronchoalveolar lavage analyses (n = 680) of 251 patients with interstitial lung disease demonstrated that eosinophils represented greater than 5% of the effector cells comprising the alveolitis in 20% of all lavages. In contrast, lavage of normal individuals (n = 117) showed that eosinophils were never greater than 5% of the total effector cells recovered. To evaluate a possible role for eosinophils in mediating some of the cellular and connective tissue matrix derangements of the lung parenchyma found in interstitial disease, eosinophils were evaluated for the presence of proteases capable of cleaving connective tissue proteins found in the lung and for the ability to mediate cytotoxicity to lung parenchymal cells. Evaluation of guinea pig and human eosinophils demonstrated that eosinophil granules contained a collagenase that specifically cleaved human collagen types I and III, the two major connective tissue components of the human lung parenchyma. In contrast, the eosinophil did not contain an elastase or a nonspecific neutral protease. The eosinophil collagenase appeared to be a metalloprotease, as it was inhibited by ethylenediaminetetraacetate but not by phenylmethanesulfonyl-fluoride or alpha 1-antitrypsin. The eosinophil also has the capacity to injure lung parenchymal cells. Without further stimulation, eosinophils purified from peritoneal exudates of guinea pigs demonstrated spontaneous cytotoxicity for human lung fibroblasts (HFL-1), cat lung epithelial cells (AK-D) and rat lung mesothelial cells (I6B). Under identical conditions, the epithelial cells were more sensitive to eosinophil-mediated cytotoxicity than the fibroblasts or mesothelial cells (P less than 0.01), consistent with the clinical observation that in the interstitial disorders, the alveolar epithelial cells are damaged more commonly than fibroblasts or pleural cells. The eosinophil-mediated cytotoxicity could be partially inhibited by the antioxidants catalase and dimethylsulfoxide suggesting that toxic oxygen radicals play a role in mediating the cellular damage. Importantly, eosinophils purified from bronchoalveolar lavage of human interstitial lung disease also demonstrated spontaneous cytotoxicity for lung epithelial cells. These observations demonstrate that eosinophils are frequent participants of the alveolitis of the interstitial lung disorders and suggest that these cells have the potential to damage the parenchymal cells and collagen matrix of the lower respiratory tract.

Animals↗