Diagnosis Of Lower Respiratory Tract Infections Research Articles

Survey of Mycoplasma pneumoniae in Iranian children with acute lower respiratory tract infections

ObjectivesMycoplasma pneumoniae is an atypical pathogen, which is one of the major causes of lower respiratory tract infections (LRTIs) worldwide. This study was performed to determine the role of M. pneumoniae in acute LRTIs in children, who were referred to main pediatric hospitals in Shiraz, Iran, with the diagnosis of LRTI. Polymerase chain reaction method on a throat-swab specimen was utilized to detect M. pneumoniae. ResultsOne hundred patients with acute LRTIs were investigated in this study. There were 10 positive PCR for M. pneumoniae (10%), including 6 of 62 hospitalized patients and 4 of 38 outpatients. All patients with LRTIs due to M. pneumoniae had cough. Fever, flu like symptoms, dyspnea, pulmonary rales, wheezing, and conjunctivitis were other common signs and symptoms. ConclusionsThe percentage of cases with M. pneumoniae infection in our population is similar to the reported in other parts of Asia. Precise and early detection of pathogen and appropriate antibiotic therapy are the key points in management of patients with LRTIs.

1309 The Etiological Value of Lactate Dehydrogenase in Respiratory Tract Viral Infections

Background: Many tissues in the body containlactate-dehydrogenase (LDH) including lungs, liverand muscles. Among five isozymes described, LDH-3 was discovered in the lungs. Interleukin6(IL-6) is a pro-inflammatory cytokine secreted by Tcells and macrophages and high serum values aresuggestive for bacterial infections. Aims: To evaluate LDH prognostic value as a markerfor etiology of lower respiratory tract infections(LRTI); to monitorise LDH values variations duringviral LRTI; to establish the correlations between “C”reactive protein (CRP) and LDH in viral LRTI. Methods: Authors have analyzed all childrenadmitted for acute LRTI (pneumonia, bronchiolitis, bronchitis) during 1 week period. The childrenwere investigated at Day 0(D0) and Day 4(D4) ofhospitalization: LDH, CRP, ASAT, ALAT, IL-6. Inclusion criteria: Children less than 7 yearsof age, no liver disease (ALAT normal range), no muscle involvement (ASAT normal value), IL-6normal range. Exclusion criteria: subjects agedmore than 7 years diagnosed with bacterial LRTI. Results: Among 88 included children, 68 subjectshad viral etiology and 20 children had bacterialcause (based on IL-6 low level). The LDH meanvalue in viral LRTI was higher than bacterial LDHmean values, not only for D0, but also for D4, without statistical correlation. There is no significantcorrelation between LDH mean value in D0 and D4in viral LRTI (p value 0,150). The authors didn't findcorrelations between LDH and CRP mean values orbetween IL-6 and CRP. Conclusions: LDH isn't a sensitive marker foretiological diagnosis of LRTI.

Maternal C-reactive protein levels in pregnancy are associated with wheezing and lower respiratory tract infections in the offspring

We assessed whether maternal C-reactive protein (CRP) levels during pregnancy and CRP gene variations are associated with wheezing and lower respiratory tract infections (LRTIs) in offspring. Information on wheezing and LRTIs in the offspring at 6 and 14 months of age, and maternal CRP levels and genotype was obtained from a population-based birth cohort. A total of 63 children (12.5%) experienced recurrent wheezing and 61 (12.4%) a recurrent diagnosis of LRTIs. Children in the highest tertile of maternal CRP levels had a higher risk of experiencing recurrent wheezing (adjusted odds ratio, 2.87; 95% confidence interval, 1.23-6.71) and being diagnosed with recurrent LRTIs (odds ratio, 2.37; 95% confidence interval, 1.01-5.55), as compared with children in the lowest tertile. The rs1205 polymorphism influenced maternal serum CRP levels but not the risk of the offspring outcomes. Higher CRP levels in pregnancy are associated with wheezing and LRTIs in offspring. However, genetic variation in CRP influencing maternal levels is not related to these phenotypes.

Children, parents and Respiratory Syncytial Virus in Palermo, Italy: prevention is primary

A study was conducted to describe the characteristics of the Respiratory Syncytial Virus (RSV) infection cases occurring in the season 2006-7 in Palermo, Italy, and to evaluate the parents' knowledge and behaviours concerning prevention and control of acute respiratory infections (ARIs). All children aged between 0 and 2 years, admitted for a lower respiratory tract infection (LRTI) between October 2006 and May 2007, were enrolled in the study. Data were collected about demographic and household characteristics. Furthermore, their parents were asked to compile a structured questionnaire on transmission, prevention and management of ARIs in children. A total of 198 children with a diagnosis of LRTI were enrolled. Ninety-eight (62.0%) of 157 were positive for RSV. Parents were generally aware of transmission of ARIs through sneezing and/or coughing, but less through contaminated objects or hands. Nationality, age and education level of parents and also the age of the patients proved to be associated with some self-reported knowledge and behaviours. Only 24 (12.3%) of the 195 respondents had received advice from GPs or paediatricians about good hygiene practices. It seems essential to implement public health interventions promoting behavioural changes aimed at the primary prevention of ARIs at the community level.

Antibiotic Prescribing and Outcomes of Lower Respiratory Tract Infection in UK Primary Care

Lower respiratory tract infection (LRTI) is common in the community and may result in hospitalization or death. This observational study aimed to investigate the role of antibiotics in the management of LRTI in the primary care setting in the United Kingdom. Patients receiving a first diagnosis of LRTI during 2004 and satisfying inclusion and data quality criteria were identified in the General Practice Research Database. Factors associated with respiratory infection-related hospital admissions and death in the 3 months following the initial diagnosis were identified using Cox proportional hazards regression. Antibiotic prescribing on the day of diagnosis was associated with a decreased rate of respiratory infection-related hospital admission (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.58 to 0.92), while antibiotic prescribing in the previous 7 days (HR, 1.92; 95% CI, 1.24 to 2.96) and prior referral or hospitalization (HR, 1.48; 95% CI, 1.20 to 1.83) were associated with an increased risk of hospital admission. Female sex (HR, 0.73; 95% CI, 0.64 to 0.84), allergic rhinitis (HR, 0.48; 95% CI, 0.27 to 0.83), influenza vaccination (HR, 0.75; 95% CI, 0.65 to 0.87), prior inhaled corticosteroid use (HR, 0.63; 95% CI, 0.52 to 0.76), and antibiotic prescription on the day of diagnosis (HR, 0.31; 95% CI, 0.26 to 0.37) were associated with decreased respiratory infection-related mortality, while a Charlson comorbidity index of >or= 2 (HR, 2.24; 95% CI, 1.72 to 2.92), antibiotic prescription in the previous 7 days (HR, 1.56; 95% CI, 1.20 to 2.03), and frequent consultation (HR, 1.62; 95% CI, 1.09 to 2.40) were associated with increased mortality. Antibiotic prescribing on the day of LRTI diagnosis was associated with reductions in hospital admissions and mortality related to respiratory infection. Antibiotics may help to prevent adverse outcomes for some patients with LRTI.

Clinico-pathological study of atypical pathogens in community-acquired pneumonia: a prospective study

Atypical respiratory pathogens such as Mycoplasma pneumoniae, Legionella species, and Chlamydia pneumoniae are isolated with increasing frequency from community-acquired pneumonia (CAP). This study highlights the importance of organisms responsible for CAP. One hundred consecutive patients with clinically and radiographically diagnosed CAP were evaluated from October 2005 to October 2006. Sputum, bronchoalveolar lavage, and blood samples were collected for microbiological culture. Determination was performed for specific immunoglobulin M (IgM) for Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, Coxiella burnettii, adenovirus, and influenza virus. The most common isolated bacteria was Streptococcus pneumoniae (22%) followed by Haemophilus influenzae (18%). Mycoplasma pneumoniae was isolated from 5% and Legionella pneumophila was isolated from 5% of patients. The most common positive serological reaction was for Chlamydia pneumoniae (30%) and Adenovirus (30%). In the study of accuracy of determination of specific IgM for Mycoplasma pneumoniae and Legionella pneumophila compared to culture, the sensitivity was 60% and 80% respectively, specificity was 93.7 %, and 98.9 % respectively, and accuracy was 92 % and 97 % respectively. This study highlights the prominence of mixed bacterial/viral infections in lower respiratory tract infection diagnosis. Our data showed that at least 30% of our patients had concurrent infections. This observation raises two important questions: 1) whether sequential or concurrent viral and bacterial infections have a synergistic impact on the evolution of disease in children; and 2) should diagnostic batteries for any patient with CAP include methods for detecting both the typical and atypical bacterial or viral pathogens.

Correlation of viral load as determined by real-time RT-PCR and clinical characteristics of respiratory syncytial virus lower respiratory tract infections in early infancy

Background In infants hospitalized for a lower respiratory tract infection (RTI) caused by respiratory syncytial virus (RSV), the correlation between viral load (VL) and patient clinical characteristics remains to be defined. Objectives To define this correlation. Study design prospective study of 47 infants admitted to hospital in the period November 2006–May 2007 with a diagnosis of lower RTI. Nasopharyngeal aspirates (NPAs) were taken at admission, discharge, and at post-discharge control visits. VL was quantified by real-time RT-PCR for RSV subgroups A and B. Results Patients with bronchiolitis were compared with young patients with lower RTI other than bronchiolitis. Patients with bronchiolitis had a significantly lower age than patients with other syndromes, and a significantly longer duration of symptoms. Duration of hospitalization was not different in the two groups of patients, and was not related to RSV subgroup or viral coinfection. A sustained decrease in VL was observed in the general patient population between admission, discharge and post-discharge follow-up visits. Conclusions (i) patients with bronchiolitis were significantly younger than patients with other lower RTIs; (ii) symptom duration was significantly longer in patients with bronchiolitis; (iii) RSV VL significantly decreased between admission and discharge.

Microbiological aspects of bacterial lower respiratory tract illness in children: typical pathogens

Whilst childhood immunization programmes have had an impact on the spectrum of pneumonic diseases seen in children, bacteria remain an important cause of lower respiratory tract infection (LRTI), particularly in younger and debilitated children. Because of the difficulty in obtaining lower respiratory tract specimens in children, specific diagnosis has often been difficult, although advances in diagnostic techniques have provided a much greater range of tools for the clinician. The challenge is to understand the application and limitation of these tests in the diagnosis of LRTI. This review examines the microbiological and diagnostic issues around Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Neisseria meningitidis and enteric Gram negative pathogens.

Use of molecular assays for the diagnosis of influenza

Respiratory infections are the third highest cause of death worldwide and influenza has the highest mortality rate among lower respiratory tract infections (LRTIs). Diagnosis of LRTIs relies mostly on clinical symptoms and is not fully satisfactory. Influenza laboratory diagnosis improves the efficiency of prophylaxis or treatment of influenza by antiviral molecules and has a strong impact on the cost–effectiveness of curative treatment. Inappropriate treatment of patients may result in spreading of resistant strains. Molecular diagnostics play a central role in the surveillance and response of pandemic influenza due to highly pathogenic strains. Real-time assays can be used for diagnosis or surveillance purposes in humans and animals, and microarrays can be used to identify and monitor the spread of dangerous variants. Molecular assays are also useful to identify and distinguish influenza, other respiratory viruses and bacteria, although their cost–effectiveness must be proven on a large scale. As new antiviral options will be available to clinicians, a better treatment choice will benefit the patient and community. Recent progress in molecular techniques will be reviewed. Examples of real-time assays for the detection of influenza viruses, including the highly pathogenic influenza A strains H5N1 and H7N7, will be discussed. Promising new techniques that allow detailed genotyping of viruses or multiplex detection of several respiratory pathogens from a unique specimen will also be discussed. These techniques will, in the near future, significantly improve the quality of diagnosis and surveillance of respiratory pathogens.

Do clinical findings in lower respiratory tract infection help general practitioners prescribe antibiotics appropriately? An observational cohort study in general practice

Antibiotics are over-prescribed for lower respiratory tract infection (LRTI). The influence of clinicians' history and examination findings on antibiotic prescribing for LRTI has not been directly assessed, and the extent to which these clinical findings predict appropriate antibiotic prescribing is unknown. A clearer understanding is crucial to achieving evidence-based prescribing. To directly assess the influence of general practitioners' history and examination findings on antibiotic prescribing for LRTI, and to explore the extent to which these clinical findings predict appropriate antibiotic prescribing. In this observational cohort study 25 GPs in The Netherlands were recruited during routine consultations and 247 adult patients with a clinical diagnosis of LRTI. The GPs recorded clinical information. Odds ratios (ORs) with 95% confidence intervals (CIs) for clinical variables predicting a prescription for an antibiotic were calculated. The relationship between antibiotic prescription and radiographic evidence of pneumonia was explored in order to gauge appropriateness of antibiotic prescribing. Auscultation abnormalities (OR 11.5; 95% CI 5.4-24.7), and diarrhoea (OR>11) were strongly associated with antibiotic prescribing. An antibiotic was prescribed for 195 (79%) patients. Assuming that an antibiotic definitely needs to be prescribed only for patients with pneumonia, antibiotics may have been inappropriately prescribed for 166/193 (86%) of the patients. Antibiotics were not prescribed for 5 of the 32 (16%) patients with a radiographic diagnosis of pneumonia. Abnormal findings on auscultation in patients with LRTI strongly predict antibiotic prescribing and this is probably inappropriate for most patients. These results should prompt GPs to consider the extent to which finding 'crackles/rhonchi on auscultation' influences their decisions to prescribe antibiotics for their patients with LRTI, and to consider the predictive value of individual clinical signs in reaching evidence-based prescribing decisions.

Impact of Rapid Detection of Viral and Atypical Bacterial Pathogens by Real-Time Polymerase Chain Reaction for Patients with Lower Respiratory Tract Infection

Background. Rapid diagnostic tests with a high sensitivity for lower respiratory tract infection (LRTI) could lead to improved patient care and reduce unnecessary antibiotic use and associated costs. Diagnostic yields, feasibility, and costs of real-time polymerase chain reaction (PCR) of nasopharyngeal and oropharyngeal swab specimens in the routine diagnostic work-up for LRTI were determined. Methods. In a randomized controlled trial, nasopharyngeal and oropharyngeal swab specimens from patients admitted for antibiotic treatment of LRTI were evaluated by means of real-time PCR for respiratory viruses and atypical pathogens, as well as by conventional diagnostic procedures. Real-time PCR results for patients in the intervention group were reported to the treating physician; results for patients in the control group were not made available. Results. A total of 107 patients (mean age [± standard deviation], 63.6 ± 16.3 years) were included, of whom 55 were allocated to the intervention group. The pathogens detected most frequently were influenza virus (14 patients), Streptococcus pneumoniae (8), coronavirus (6), Staphylococcus aureus (5), and rhinoviruses (5). Real-time PCR increased the diagnostic yield from 23 cases (21% of patients) to 47 cases (43% of patients), compared with conventional diagnostic tests. The detection of viral pathogens by PCR was associated with the winter season, less infiltrates on chest radiographs, lower C-reactive protein levels, and shorter duration of symptoms. Use of real-time PCR results resulted in partial or total cessation of antibiotic treatment for 6 patients (11%; 95% confidence interval, 2–19), but overall antibiotic use was comparable in the intervention group and the control group (median duration of treatment, 10.0 vs. 9.0 days; P = not significant). Use of real-time PCR increased treatment and diagnostic costs with €318.17 per patient. Conclusions. Implementation of real-time PCR for the etiological diagnosis of LRTI increased the diagnostic yield considerably, but it did not reduce antibiotic use or costs.

Viral etiology of lower respiratory tract infections in hospitalized children in Mexico.

Respiratory viruses are the main cause of lower respiratory tract infections (LRTI) reported worldwide. The contribution of viral infections to respiratory infections in Mexico has not been fully determined. To determine the contribution of viral infections in hospitalized children with LRTI. Children younger than 15 years of age with the admission diagnosis of LRTI were eligible for this study. A nasal wash specimen for virus identification by direct immunofluorescent assay (DFA) was obtained as soon as possible after admission. Clinical and radiographic findings of children with positive and negative detection of viruses were compared. Of 285 subjects admitted to the hospital with LRTI, 265 (93%) had an appropriate specimen for DFA. A viral agent was detected in 125 (47.2%) specimens. Viruses that were identified included respiratory syncytial virus (107), influenza (9) and parainfluenza type 3 (9). Clinical and radiologic diagnoses included bronchiolitis (127), interstitial pneumonia (47) and pneumonia (91). Of the subjects included in the study, 71.3% were younger than 1 year of age. Children with a confirmed viral etiology for their LRTI were younger, had higher respiratory rates on admission and were more likely to present with bronchiolitis than subjects with a negative DFA result. Respiratory viruses are responsible for at least 47.2% of LRTI requiring hospitalization at our hospital. Respiratory syncytial virus was the most important respiratory agent identified.

Can We Improve Etiologic Diagnosis of Pediatric Pneumonia

Lack of specific noninvasive diagnostic tests has impeded the etiologic diagnosis of lower respiratory infections (LRIs) in children. Previous clinical studies have shown a considerable proportion of cases with an unidentified cause. This prospective investigation, performed before routine use of the conjugate pneumococcal vaccine, differs from earlier …

Use of a treatment protocol in the management of community-acquired lower respiratory tract infection

The aim of the present study was to examine the impact of an antimicrobial prescribing protocol on clinical and economic outcome measures in hospitalized patients with community-acquired lower respiratory tract infection (LRTI). The study was performed as a prospective controlled clinical trial within the medical wards at Antrim Area Hospital, Northern Ireland. Data were collected on all hospitalized adult patients with a primary diagnosis of LRTI during the period December 1994 to February 1995 (normal hospital practice; control group; n = 112). After an LRTI management protocol (medical, microbiological and pharmacy staff) had been developed, all hospitalized adult patients with a primary diagnosis of LRTI over the period December 1995 to February 1996 formed the intervention group (treated according to the protocol; n = 115). The results showed a statistically significant impact of the protocol in terms of clinical and economic outcome measures. Patients treated using the algorithmic prescribing protocol had significant reductions in length of hospital stay (geometric mean 4.5 versus 9.2 days), iv drug administration (34.8% versus 61.6%), duration of iv therapy (geometric mean 2.1 versus 5.7 days) and treatment failures (7.8% versus 31.3%). Healthcare costs were also significantly reduced. The use of the protocol was a major factor in streamlining the prescribing of antimicrobial therapy for community-acquired LRTI and led to more cost-effective patient management.

A randomised, multicentre study of ceftriaxone versus standard therapy in the treatment of lower respiratory tract infections

In this study the efficacy and cost-effectiveness of i.v. ceftriaxone 1 g once daily (CTX) was compared with standard i.v. antibiotic treatment (STD) for lower respiratory tract infections (LRTI). STD was given according to the guidelines of the American Thoracic Society and consisted of either cefuroxime 1500 mg three times daily (q8h), amoxicillin/clavulanic acid 1200 mg q8h or ceftriaxone 2 g once daily; each with or without a macrolide. After a minimum of 5 days i.v. therapy, patients could be switched to oral therapy. One hundred patients were enrolled in the study; 52 patients received CTX and 48 STD. Groups were comparable with respect to demographic and baseline characteristics. Seventy patients had a confirmed diagnosis of pneumonia. Twenty-nine patients had a severe type I exacerbation of chronic bronchitis. In one patient the diagnosis of LRTI could not be confirmed. In approximately 50% of the patients a microbiological diagnosis could be made. The most important isolated pathogens from sputum and blood were (positive blood cultures in brackets): Streptococcus pneumoniae 14 (9) and Haemophilus influenzae 16. Mean duration of i.v. therapy was 7.4 days in both groups. Average duration of hospitalisation was 15.0 days for CTX patients and 15.9 days for STD patients. Overall cure and improvement rate at the end of treatment was 47 (90%) for patients receiving ceftriaxone 1 g compared to 37 (77%) for patients receiving standard therapy. Pathogens were eradicated or presumed to be eradicated in 84% of the CTX patients and in 76% of the STD patients. Mean total costs per treatment were lower for CTX than for STD treatment: NLG 169 versus 458. These results show, that i.v. ceftriaxone 1 g once daily is as effective as standard therapy in the treatment of LRTI and that its use reduces treatment costs, in view of the multiple daily dosing regimens of most standard therapies.

Pneumococcal immune complexes in the diagnosis of lower respiratory infections in children.

In recent years serologic methods have been applied to assess pneumococcal etiology of pneumonia and other respiratory tract infections. Antigen and antibody assays have shown to be insensitive, especially in young children. The aim of this study was to evaluate the usefulness of circulating immune complexes in the diagnosis of pneumococcal lower respiratory infection in children. Pneumococcal immune complexes (IC) containing antibodies to species-specific C-polysaccharide, to mixtures of type-specific capsular polysaccharides or to a protein antigen, pneumolysin, were studied in the sera of 449 children with lower respiratory tract infection. Circulating ICs were found in 68 (15%) children; 46 (68%) of them were demonstrated in acute and 43 in convalescent serum. In 5 (7%) of the 68 IC-positive patients pneumococcal antigen was present in acute serum; those patients formed 18% of the 28 cases with antigenemia. An antibody response between paired sera to any of the 3 pneumococcal antigens studied was observed in 14 (21%) IC-positive children; they formed 23% of the 60 cases with an antibody response. In total ICs were positive in 51% of all the 134 pneumococcal cases diagnosed by any method. We conclude that the measurement of circulating ICs is more sensitive than other serologic methods for the diagnosis of pneumococcal lower respiratory infection. In infants, however, it was as insensitive as antigen and antibody assays.

Reliability of the chest radiograph in the diagnosis of lower respiratory infections in young children: Davies HD, Wang EE-L, Manson D, et al. Pediatr Infect Dis J. 1996;15:600–604

Reliability of the chest radiograph in the diagnosis of lower respiratory infections in young children: Davies HD, Wang EE-L, Manson D, et al. Pediatr Infect Dis J. 1996;15:600–604

Reliability of the chest radiograph in the diagnosis of lower respiratory infections in young children.

This study was conducted to determine the reliability of detecting features and making diagnoses of lower respiratory infections from chest radiograms in young infants. Forty chest radiograms of infants younger than 6 months of age admitted with lower respiratory tract infection to a tertiary care pediatric hospital were independently reviewed on two separate occasions by three pediatric radiologists blinded to the patients' clinical diagnoses. For each radiograph the radiologists noted whether a feature was present, absent or equivocal on a standardized form. The features examined were hyperinflation, peribronchial thickening, perihilar linear opacities, atelectasis and consolidation. On the same form each radiologist indicated whether the radiograph was normal or showed airways and/or airspace disease. Within and between observer agreement were calculated by the average weighted kappa statistic. Within observer agreement for the radiologic features of hyperinflation, peribronchial wall thickening, perihilar linear opacities, atelectasis and consolidation were 0.85, 0.76, 0.87, 0.86 and 0.91, respectively. The between observer kappa results for these features were 0.83, 0.55, 0.82, 0.78 and 0.79, respectively. The within and between observer kappa statistics for interpretation of the radiographic features were best for airspace disease (within, 0.92; between, 0.91), and lower for normal (within, 0.80; between, 0.66) radiogram and for airways disease (within, 0.68; between, 0.48). The presence of consolidation was highly correlated with a diagnosis of airspace disease by all three radiologists. Clinicians basing the diagnosis of lower respiratory infections in young infants on radiographic diagnosis should be aware that there is variation in intraobserver and interobserver agreement among radiologists on the radiographic features used for diagnosis. There is also variation in how specific radiologic features are used in interpreting the radiogram. However, the cardial finding of consolidation for the diagnosis of pneumonia appears to be highly reliable.

Diagnosis of Legionella pneumophila, Mycoplasma pneumoniae, or Chlamydia pneumoniae lower respiratory infection using the polymerase chain reaction on a single throat swab specimen

Diagnosis of Mycoplasma pneumoniae and Chlamydia pneumoniae lower respiratory infections using DNA amplification by polymerase chain reaction (PCR) on throat swab specimens has been reported. In this study we determined the sensitivity of the detection of Legionella pneumophila in simulated throat swab specimens by PCR. Next, we compared the sensitivity and specificity of a single throat swab PCR with the current tests for diagnosis of Legionella spp., M. pneumoniae, and C. pneumoniae in patients with lower respiratory tract infections. Patients' work-up included: (a) throat swab speciment for Legionella spp., M. pneumoniae, and C. pneumoniae PCR; (b) throat swab specimen for C. pneumoniae, culture; (c) sputum specimen for L. pneumophila direct fluorescent antibody and culture; (d) urine specimen for L. pneumophila serogroup 1 antigen detection; and (e) serum specimen for L. pneumophila, M. pneumoniae, and C. pneumoniae acute and convalescent antibody titers. A total of 155 patients with lower respiratory infection were enrolled in this prospective study. Throat swab PCR was positive for Legionella spp. in five of the six patients with legionellosis, indicating the presence of this organism in the oropharynx of patients with Legionnaires disease. Mycoplasma pneumoniae PCR was positive in eight of the nine patients with mycoplasma infection. Chlamydia pneumoniae PCR was positive in the two patients with C. pneumoniae infection. None of the other 138 patients with negative PCR had other positive confirmatory tests for respiratory infection by these three organisms (100% specificity). PCR was able to detect 15 of the 17 infected (88.2%). Results of this investigation indicate that PCR on a single throat swab specimen is a rapid, sensitive, and specific test that may greatly simplify the diagnosis of lower respiratory infection caused by Legionella spp., Mycoplasma pneumoniae, or C. pneumoniae.

Laboratory Diagnosis of Lower Respiratory Infection

Laboratory Diagnosis of Lower Respiratory Infection