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PubMed2000

Antibiotics for preventing respiratory tract infections in adults receiving intensive care.

OBJECTIVES: Pneumonia is an important cause of mortality in intensive care units. The objective of this review was to assess the effects of antibiotics for preventing respiratory tract infections and overall mortality in adults receiving intensive care. SEARCH STRATEGY: We searched MEDLINE, proceedings of scientific meetings and reference lists of articles from January 1984 to September 1997. We also contacted investigators in the field. SELECTION CRITERIA: Randomised trials of antibiotic prophylaxis for respiratory tract infections and deaths among adult intensive care unit patients. DATA COLLECTION AND ANALYSIS: Trials were assessed for quality and investigators contacted for additional information. MAIN RESULTS: Overall 33 trials involving 5727 people were included. There was variation in the antibiotics used, patient characteristics and the risk of respiratory tract infections and mortality in the control groups. In 16 trials (involving 3493 patients) of a topical and systemic antibiotic combination, the average rates of respiratory tract infections and deaths in the control group were 33% and 28% respectively. There was a significant reduction of both respiratory tract infections (odds ratio 0.36, 95% confidence interval 0.30 to 0. 43) and total mortality (odds ratio 0.80, 95% confidence interval 0. 68 to 0.93). On average five patients needed to be treated to prevent one infection and 23 treated to prevent one death. In 17 trials (involving 2366 patients) of topical antimicrobials the rates of respiratory tract infections and deaths in the control groups were 30% and 24% respectively. There was a significant reduction of respiratory tract infections (odds ratio 0.57, 95% confidence interval 0.46 to 0.69) but not in total mortality (odds ratio 1.01, 95% confidence interval 0.84 to 1.22). REVIEWER'S CONCLUSIONS: A combination of topical and systemic prophylactic antibiotics can reduce respiratory tract infections and overall mortality in adult patients receiving intensive care. [This abstract has been prepared centrally.]

Adult↗
PubMed1982

Herpes simplex virus from the lower respiratory tract in adult respiratory distress syndrome.

Herpes simplex virus (HSV) was found in the tracheobronchial secretions of 14 of 46 (30%) consecutive patients with the adult respiratory distress syndrome (ARDS). The HSV has not hitherto been associated with ARDS, and most previous reports of HSV in the lower respiratory tract have come from autopsy material. In the present study, the diagnosis during life was initially made by identification of the characteristic inclusion bodies of HSV in bronchial epithelial cells obtained from tracheobronchial aspiration. The presence of HSV in the lower respiratory tract was associated with the need for more prolonged respiratory support and an increased late mortality.

Adult↗
PubMed1996

Purified fusion protein vaccine protects against lower respiratory tract illness during respiratory syncytial virus season in children with cystic fibrosis.

OBJECTIVE: To test in a double blind, placebo-controlled study a purified fusion protein (PFP-2) vaccine against respiratory syncytial virus (RSV) in RSV-seropositive children with cystic fibrosis (CF). METHODS: Seventeen CF children, mean age 4.5 years, received PFP-2 vaccine and 17 CF children, mean age 5.8 years, received a saline vaccine. At enrollment the Shwachman clinical score, Brasfield radiographic score, oxygen saturation (SpO2), anthropometric indices and other variables were recorded. After vaccination the reactions were assessed daily for 7 days. During the RSV season weekly telephone interviews were performed and children with an acute respiratory illness were evaluated and cultured for RSV. Serum was drawn before vaccination, 1 month after vaccination and at the end of the RSV season and tested for antibodies to RSV. RESULTS: Other than age the baseline measurements at enrollment were similar between groups. The PFP-2 vaccine produced mild local reactions and induced a significant neutralizing antibody response in two-thirds of the vaccinees and a significant enzyme-linked immunosorbent assay-fusion glycoprotein antibody response in nearly all the PFP-2 vaccinees. Vaccine-enhanced disease was not observed in PFP-2 vaccines infected with RSV. Protection against RSV infection was not observed; however, a significant reduction (t test, P < 0.01) in mean number of lower respiratory tract illnesses (0.8 vs. 2.1), antibiotic courses (2.2 vs 4.5) and days ill (30.5 vs. 67) occurred among RSV-infected PFP-2 vaccinees. CONCLUSIONS: Efficacy of the PFP-2 vaccine against lower respiratory tract illness during the RSV season was shown in RSV-seropositive children with CF.

Child↗
PubMed2005

Chinchilla and murine models of upper respiratory tract infections with respiratory syncytial virus.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in infants and the elderly. While the primary infection is the most serious, reinfection of the upper airway throughout life is the rule. Although relatively little is known about either RSV infection of the upper respiratory tract or host mucosal immunity to RSV, recent literature suggests that RSV is the predominant viral pathogen predisposing to bacterial otitis media (OM). Herein, we describe mouse and chinchilla models of RSV infection of the nasopharynx and Eustachian tube. Both rodent hosts were susceptible to RSV infection of the upper airway following intranasal challenge; however, the chinchilla proved to be more permissive than the mouse. The chinchilla model will likely be extremely useful to test the role of RSV in bacterial OM and the efficacy of RSV vaccine candidates designed to provide mucosal and cytotoxic T-lymphocyte immunity. Ultimately, we hope to investigate the relative ability of these candidates to potentially protect against viral predisposal to bacterial OM.

Animals↗
PubMed1999

Optimal induction of upper respiratory tract immunity to reovirus 1/L by combined upper and lower respiratory tract inoculation.

There has been an increasing interest in developing vaccines which are both easy to administer and which elicit functionally protective immune responses at mucosal and/or systemic sites. Intranasally administered vaccines meet the criteria of ease of administration and are thought to stimulate respiratory-mucosal immunity via interaction with nasal associated lymphoid tissues (NALT). The aim of this study was to gain a better understanding of how best to stimulate respiratory-mucosal immunity using a murine model of respiratory reovirus infection. Either a predominantly upper respiratory tract infection or a combination upper and lower respiratory tract infection was established by administering the same virus dose in either a small or large inoculum volume. These studies demonstrate that stimulation of NALT alone by an upper respiratory tract infection does not induce an optimal primary antibody response even in the nasal cavity. Effective immunity of both the upper and lower respiratory tract was obtained when a combination upper and lower respiratory tract infection was established. These results have important clinical implications since they suggest that effective respiratory mucosal immunity will be best achieved by the combined stimulation of both the upper and lower respiratory tract and will likely require both intranasal as well as inhaled aerosol delivery of antigen to the lower respiratory tract in humans.

Administration, Intranasal↗
PubMed1992

Detection of human papillomavirus infection in diseased and nondiseased sites of the respiratory tract in recurrent respiratory papillomatosis patients by DNA hybridization.

We examined 12 recurrent respiratory papillomatosis patients, who were undergoing treatment for recurrence of their disease, for the presence of human papillomavirus (HPV). Biopsies were obtained from their respiratory papillomas and nondiseased sites (NDS) of the respiratory tract: the nasopharynx, posterior tonsillar pillar, aryepiglottic fold, cervical trachea, intrathoracic trachea, and bronchi. The presence of HPV DNA was determined by using the ViraPap/ViraType DNA hybridization procedure. Two thirds of the patients were infected with HPV 6/11 in either the diseased papilloma or NDS: 50% of patients with papilloma specimens typed positive (6 of 12), and 40% of the patients typed HPV-positive in one or more biopsies from the NDS (4 of 10). No single NDS was more likely to be infected with HPV than any other. No oncogenic HPV types 16/18 or 31/33/35 were detected in the papillomas or NDS of these patients. Only patients with multiple, and not isolated, papilloma involvement were found to harbor HPV DNA in NDS; and 80% of those with infected NDS, compared to 20% of those without infected NDS, required a shorter (no more than 3 months) surgical treatment interval. Our results show that HPV infection frequently persists in adjacent, clinically normal sites, and suggest that the extent of NDS involvement may predict both the extent of disease and the likelihood of recurrence.

Adolescent↗
PubMedDate not supplied

Epidemiology of respiratory syncytial virus in children with lower respiratory tract infection.

Respiratory syncytial virus (RSV) is the most frequent pathogen found in hospitalized young children with lower respiratory tract infection, and the virus is distributed worldwide. Respiratory distress and respiratory failure are caused by RSV in some severe cases. Its appearance always varies every year and depends on differences of latitudes, altitudes and climates. The purpose of this study was to investigate the epidemiology of hospitalized children from a hospital located in northern Taiwan with RSV induced lower respiratory tract infection. This study was conducted from January 2001 to December 2003, and the selected patients were children aged under five and diagnosed with lower respiratory tract infection. The means adopted in this study were analyses of clinical presentations and laboratory tests (including viral identification with either virus culture or RSV antigen rapid test from the nasopharyngeal aspirate). The results showed that 153 children were positive with RSV identification. These cases were diagnosed in clinical practice all year round, and its peak was in spring, especially in March and April. Thirteen percent of all RSV-infected children in this study presented as severe form with respiratory distress and a need of respiratory support. However, none of these cases died from this disease, and all cases recovered without long-term respiratory complication. We concluded that RSV infection was still a common pathogen for young children in northern Taiwan; in addition, March and April were regarded as peak months of epidemic. Patients aged under 12 months or suffered from underlying cardiopulmonary disease were at high risk of getting severe forms of RSV infection.

Cardiovascular Diseases↗
PubMed1996

Intranasal monoclonal IgA antibody to respiratory syncytial virus protects rhesus monkeys against upper and lower respiratory tract infection.

Respiratory syncytial virus (RSV), the major cause of lower respiratory tract disease in infants, is thought to infect the upper airways before spreading to the lower respiratory tract. A rhesus monkey model of RSV infection after upper airway inoculation was used to test the protective effect of intranasal treatment with HNK20, a mouse monoclonal IgA antibody against RSV F glycoprotein. HNK20 was administered once daily for 2 days before RSV challenge and 4 days after challenge. Treatment with 0.5 mg/kg HNK20 reduced viral shedding in the nose, throat, and lungs by 3-4 log10/mL (P < or = .002). All monkeys developed RSV neutralizing antibody in serum, even in the absence of detectable viral replication. Neutralizing concentrations of monoclonal antibody remained in nasal secretions for > 1 day after treatment. These results suggest that nose-drop application of monoclonal antibody could provide convenient and effective protection against RSV infection in human infants at risk of severe lower respiratory tract disease.

Administration, Intranasal↗
PubMed2005

Acute lower respiratory tract infections and respiratory syncytial virus in infants in Guinea-Bissau: a beneficial effect of BCG vaccination for girls community based case-control study.

Among measles unvaccinated infants in Guinea-Bissau, we tested whether case infants with acute lower respiratory tract infection (ALRI), especially ALRI caused by respiratory syncytial virus (RSV), were more likely to be Bacille Calmette Guerin (BCG)-unvaccinated and to have no scar after BCG vaccination than were control infants without symptoms of ALRI. Three hundred and eighty-six case infants with ALRI were identified at a paediatric clinic (N=84), a health centre (N=82), and in a community morbidity surveillance system (N=220). Control infants were matched on sex, age, and district and were also measles unvaccinated. In ALRI case infants, the adjusted OR of being BCG unvaccinated was 2.87 (1.31-6.32), 1.72 (0.48-6.19) in boys and 4.45 (1.48-13.4) in girls. Among BCG vaccinated ALRI case infants, the adjusted OR of having no BCG scar was 1.54 (0.86-2.75), 0.93 (0.45-1.91) in boys and 2.70 (1.21-6.02) in girls. In ALRI case infants with RSV infection, similar trends were observed. BCG vaccination may have a non-targeted protective effect against ALRI, the effect being most marked in girls.

BCG Vaccine↗
PubMed1981

[Pharmacological effects of N-acetyl-L-cysteine on the respiratory tract. (I). Quantitative and qualitative changes in respiratory tract fluid and sputum (author's transl)].

The following three experiments were performed to determine the effects of N-acetyl-L-cysteine (NAC) on the quantity and quality of respiratory tract fluid (RTF) and sputum. All drugs used were administered into the stomach through a gastric tube. 1) Indirect measurement of bronchial secretion in rats, which was expressed by the amounts of dye excreted into the respiratory tract, was carried out according the the Sakuno's method, with some modification. Some expectorants of the secretomotor type, such as bromhexine and pilocarpine, significantly increased the secretion, even at low doses. On the other hand, mucolytic agents such as NAC augmented the secretion only in doses of 500 to 1500 mg/kg. 2)As a direct method of measurements, Kasé's modification of Perry and Boyd's method was used to collect RTF, quantitatively, from rabbits. The RTF of healthy rabbits was colorless and watery. The administration of NAC in doses of 500 to 1500 mg/kg augmented the output volume and RTF became slightly turbid, probably due to an increase in the viscous mucus. 3) Rabbits with subacute bronchitis were prepared by long-term exposure to air contaminated with SO2 gas and sputa were collected before and after administration of NAC, respectively, according to the Kase's method. The sputa were opalescent and viscous gel included nodular masses. The administration of NAC, 1000 and 1500 mg/kg resulted in a dose dependent decrease in the relative viscosity. The percent-decreased in viscosity with NAC was statistically correlated with that in amounts of dry matter, those in protein and polysaccharide in the sputa. From the results described above, it was concluded that NAC given into the stomach can liquefy sputum by splitting mucoprotein disulphide linkages, that is, altering the rheological characteristics of sputum to facilitate expectoration.

Acetylcysteine↗
PubMed1992

Eosinophil degranulation in the respiratory tract during naturally acquired respiratory syncytial virus infection.

Eosinophil cationic protein (ECP), a cytotoxic protein contained in the granules of eosinophils, has been suggested as having an important role in the pathogenesis of asthma. To determine whether ECP plays a similar role in bronchiolitis, we tested samples of nasopharyngeal secretions, obtained from a group of 47 children with various forms of illness related to respiratory syncytial virus (RSV) and from 26 children with non-RSV upper respiratory tract illness or bacterial pneumonia, for the presence of ECP by means of a double-antibody radioimmunoassay. Concentrations of ECP in children with RSV bronchiolitis were significantly higher (166.8 ng/ml) than the mean concentration of ECP in both groups of children with RSV upper respiratory tract illness (43.5 ng/ml, p less than 0.002) and RSV lower respiratory tract disease without wheezing (29.1 ng/ml; p less than 0.0002). Children with non-RSV upper respiratory tract illness or bacterial pneumonia had levels of ECP in nasopharyngeal secretions similar to those of children with RSV upper respiratory tract illness or RSV pneumonia. High ECP levels in nasopharyngeal secretions (greater than 50 ng/ml) were predictive of the development of bronchiolitis at the time of RSV infection (p less than 0.001), and the individual ECP levels correlated with severity of the disease as determined by the initial PaO2 concentrations (p less than 0.05). These data suggest that eosinophil degranulation in the respiratory tract occurs during RSV bronchiolitis and may play a significant role in the development of virus-induced airway obstruction.

Bacterial Infections↗
PubMedDate not supplied

Bacterial colonization of the upper respiratory tract and its association with acute lower respiratory tract infections in Highland children of Papua New Guinea.

Acute lower respiratory tract infection (ALRI) is the major cause of death among children in Papua New Guinea. This longitudinal study reports the bacteriologic findings for children observed in their hamlets. A total of 1,449 nasal swab specimens from 158 children less than 5 years of age who were studied intensively for 18 months were examined. Non-serotypable strains of Haemophilus influenzae were isolated from 91% of specimens, and serotypable strains were isolated from 35% (8% H. influenzae type b) of specimens. All children had acquired Streptococcus pneumoniae by the age of 3 months. The most frequently occurring serotypes of S. pneumoniae were 6, 19, and 23. Children more frequently carried invasive pneumococci during an episode of ALRI than when they were healthy. Also, children more frequently carried serotypable strains of H. influenzae during the 2 weeks preceding an episode of ALRI than when they were healthy. Between-children analyses showed that children who were susceptible to attacks of ALRI and those who were not susceptible had similar rates of carriage of bacteria.

Age Factors↗
PubMed1994

[Bacterial flora of the respiratory tract in patients with long term tracheostomy--colonization of the lower respiratory tract by Pseudomonas aeruginosa].

Throat secretions (TS) and bronchial secretions aspirated from tracheostomy sites (TSTA) from six subjects with long term tracheostomy were simultaneously collected and then cultured every two weeks from January, 1990, to December, 1992. Isolated bacteria were mainly alpha-streptococci (96.2%) and Neisseria (69.6%) in TS, and Pseudomonas aeruginosa (75.7%) in TSTA. In all cases, P. aeruginosa was isolated from and colonization of the lower respiratory tract by this organism was apparent 24.4 months, on average, after tracheostomy. There were ten episodes of respiratory infection in five cases, eight of which occurred after colonization. P. aeruginosa was the causative organism in seven of these episodes. Findings in patients with long term tracheostomy indicated separate colonization of the upper and lower respiratory tracts and that P. aeruginosa colonized the lower respiratory tract. The colonization of the lower respiratory tract by P. aeruginosa would thus appear to be an important factor inducing respiratory infection.

Adult↗
PubMed2000

Ribavirin for respiratory syncytial virus infection of the lower respiratory tract.

OBJECTIVES: Respiratory syncytial virus (RSV) is a common cause of pneumonia in infants. Ribavirin is the only antiviral therapy available against RSV. The objective of this review was to assess the effects of aerosolized ribavirin for infants with RSV lower respiratory tract infection. SEARCH STRATEGY: We searched MEDLINE from 1975 to 1999, we scanned reference lists of articles, and we contacted experts in the field. SELECTION CRITERIA: Randomized trials comparing ribavirin with placebo in infants and children with RSV infection and lower respiratory tract infection. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. Unpublished data were requested from authors when necessary. MAIN RESULTS: Ten trials were included. All trials enrolled infants below the age of six months. In four trials with 158 patients, mortality with ribavirin was 5.8% compared with 9.7% with placebo (odds ratio 0.58, 95% confidence interval 0.18 to 1.85). In three trials with 116 patients the probability of respiratory deterioration with ribavirin was 7.1% compared with 18.3% with placebo (odds ratio 0.37, 95% confidence interval 0.12 to 1.18). In three studies with 104 patients the weighted mean difference in days of hospitalization was 1.9 fewer days with ribavirin (95% confidence interval +0.9 to -4.6) and the difference in days of ventilation was 1.2 fewer days with ribavirin (95% confidence interval -0.2 to -3.4). REVIEWER'S CONCLUSIONS: Trials of ribavirin for RSV lack sufficient power to provide reliable estimates of the effects. The cumulative results of three small trials show that ribavirin reduces length of mechanical ventilator support and may reduce days of hospitalization. A large randomized controlled trial of ribavirin for ventilated and other high-risk patients is indicated.

Antiviral Agents↗
PubMed2000

The epidemiology of respiratory tract infections.

Respiratory tract infections (RTIs) are the most common, and potentially most severe, of infections treated by health care practitioners. Lower RTIs along with influenza, are the most common cause of death by infection in the United States. Risk factors for pneumonia and other respiratory tract infections include: extremes of age (very young and elderly), smoking, alcoholism, immunosuppression, and comorbid conditions. The microbial cause of RTIs vary depending on the infection (i.e., pneumonia compared with acute bacterial sinusitis), setting (i.e., community-acquired compared with nosocomial), and other factors. The causative pathogens associated with CAP have changed in prevalence over time. Although Streptococcus pneumoniae remains the most common causative pathogen, a number of newer pathogens, such as Chlamydia pneumoniae and sin nombre virus, have been recognized in recent years. The emerging antimicrobial resistance of respiratory pathogens (most notably S. pneumoniae) has also increased the challenge for appropriate management of RTI. An awareness of the epidemiology and cause of specific respiratory infections should optimize care.

Adolescent↗