Evaluation of pneumococcal urinary antigen testing for respiratory tract infection investigations.

OBJECTIVE: The pneumococcal urinary antigen test enables rapid bacteriological diagnosis in respiratory tract infections. The objective was to identify factors associated with a positive pneumococcal urinary antigen test result. PATIENTS AND METHODS: This seven-year retrospective monocentric study was performed on consecutive patients presenting with respiratory tract infections reported as pneumococcal-positive. Epidemiological, biological, and radiological factors were analyzed, and severity scores were calculated. RESULTS: A total of 223 patients were included. Significant associations were observed between positive test results and age over 65years (P=0.01), positive test results and immunosuppression factors (blood disease [25% Ag+ group vs. 4% Ag- group, P=0.001], immunosuppressive therapy [10% Ag+ group vs. 0% Ag- group, P=0.02]). Clinically, fever (64% Ag+ group vs. 42% Ag- group, P=0.01) and cough (46% Ag+ group vs. 19% Ag- group, P<0.01) were associated with a positive result, as were radiological alveolar opacities (67% Ag+ group vs. 44% Ag- group, P=0.01). High PSI score was associated with the Ag+ group (79% vs. 56% Ag- group, P=0.001). CONCLUSION: Age, immunosuppressive factors, typical pneumococcal symptoms, and PSI scores were associated with a positive pneumococcal urinary antigen result.

Metabolomic profile of children with recurrent respiratory infections.

Recurrent respiratory infections (RRI) represent a widespread condition which has a severe social and economic impact. Immunostimulants are used for their prevention. It is crucial to better characterize children with RRI to refine their diagnosis and identify effective personalized prevention strategies. Metabolomics is a high-dimensional biological method that can be used for hypothesis-free biomarker profiling, examining a large number of metabolites in a given sample using spectroscopic techniques. Multivariate statistical data analysis then enables us to infer which metabolic information is relevant to the biological characterization of a given physiological or pathological condition. This can lead to the emergence of new, sometimes unexpected metabolites, and hitherto unknown metabolic pathways, enabling the formulation of new pathogenetic hypotheses, and the identification of new therapeutic targets. The aim of our pilot study was to apply mass-spectrometry-based metabolomics to the analysis of urine samples from children with RRI, comparing these children's biochemical metabolic profiles with those of healthy peers. We also compared the RRI children's and healthy controls' metabolomic urinary profiles after the former had received pidotimod treatment for 3 months to see whether this immunostimulant was associated with biochemical changes in the RRI children's metabolic profile. 13 children (age range 3-6 yeas) with RRI and 15 matched per age healthy peers with no history of respiratory diseases or allergies were enrolled. Their metabolomic urine samples were compared before and after the RRI children had been treated with pidotimod for a period of 3 months. Metabolomic analyses on the urine samples were done using mass spectrometry combined with ultra-performance liquid chromatography (UPLC-MS). The resulting spectroscopic data then underwent multivariate statistical analysis and the most relevant variables characterizing the two groups were identified. Data modeling with post-transformation of PLS2-Discriminant Analysis (ptPLS2-DA) generated a robust model capable of discriminating the urine samples from children with RRI from those of healthy controls (R2=0.92,Q2CV7-fold=0.75, p-value<0.001). The dataset included 1502 time per mass variables, and 138 of them characterized the difference between the two groups. Thirty-five of these distinctive 138 variables persisted in the profiles of the children with RRI after pidotimod treatment. Metabolomics can discriminate children with RRI from healthy controls, suggesting that the former have a dysregulated metabolic profile. Among the variables characterizing children with RRI there are metabolites that may reflect the presence of a different microbiome. After pidotimod treatment, the metabolic profile of the children with RRI was no longer very different from that of the healthy controls, except for the persistence of some microbiome-related variables. We surmise that pidotimod partially "restores" the altered metabolic profile of children with RRI, without modifying the metabolites related to the composition of the gut microbiota. In the light of these results, we hypothesize a potential synergic effect of the combined use of immunostimulants and probiotics for the purpose of prevention in children with RRI.

Urinary leukotriene E4 levels in atopic and non-atopic preschool children with recurrent episodic (viral) wheezing: a potential marker?

UNLABELLED: Backround: Reliable biological markers for the differentiation of asthma phenotypes in preschool children with wheezing are lacking. The purpose of the study is to assess the relationship of urinary Leukotriene E4 (U-LTE4) to particular asthma phenotypes in preschool children with recurrent episodic (viral) wheezing following upper respiratory tract infections with or without atopic predisposition. METHODS: Ninety-six preschool patients with recurrent episodic wheezing participated, 52 atopic and 44 non-atopic, during exacerbation and in remission. Exacerbation was defined on clinical basis (wheeze in the presence of coryzal symptoms). Atopy was determined by specific serum IgE measurement and skin-prick testing. U-LTE4 was determined by enzyme immunoassay. Thirty-six age-matched, non-asthmatic, non-atopic children served as controls. RESULTS: During exacerbation, U-LTE4 was significantly higher in all children with recurrent episodic wheezing in comparison to A: Remission: 642.20 ± 268 versus 399.45 ± 204, p value <0.001 and B: CONTROLS: 642.20 ± 268 versus 271.39 ± 83, p value <0.001. Atopic patients demonstrated significantly higher levels of U-LTE4 compared to non-atopic, both during exacerbation 872.13 ± 246 versus 613.15 ± 150, p value = 0.0013 and during remission 507.59 ± 182 versus 283.59 ± 160, p value <0.001. During remission, a highly significant difference of U-LTE4 was found when controls were compared to atopic patients: 271.39 ± 83 versus 507.59 ± 182, p value = 0.002 but not when compared to non-atopic ones: 271.39 ± 83 versus 283.59 ± 160, p value = 0.432. CONCLUSION: U-LTE4 is strongly associated with the acute wheeze episode in preschool children, more so in atopics. Increased basal levels of U-LTE4 occur only in atopics. This suggests a potential role of U-LTE4 as a marker of atopic, virus-induced asthma in preschool children.

Evaluation of a rapid immunochromatographic ODK0501 assay for detecting Streptococcus pneumoniae antigens in the sputum of pneumonia patients with positive S. pneumoniae urinary antigens.

BACKGROUND: A novel, rapid and noninvasive test (ODK0501, RAPIRUN(®)Streptococcus pneumoniae) uses polyclonal antibodies to detect C polysaccharide of S. pneumoniae derived from sputum samples using an immunochromatographic assay. We evaluated its usefulness in Japanese patients with pneumonia who exhibited positive urinary antigen tests for S. pneumoniae (BinaxNOW(®)S. pneumoniae). PATIENTS AND METHODS: Forty adult patients with pneumonia treated between May 2011 and August 2013 were enrolled. Bacterial cultures, Gram staining and ODK0501 assays of sputum as well as urinary antigen tests for S. pneumoniae using urine samples obtained from the same patients were performed upon admission, the fourth day after starting antimicrobial treatment and at the end of the antimicrobial treatment. RESULTS: Twenty-seven of the 40 patients were positive for ODK0501, while a negative result for ODK0501 was associated with low-quality sputum samples according to the Geckler classification of sputum. The sensitivity and specificity of the ODK0501 assay in the 40 patients were 90.9% and 61.1%, respectively, based on the culture results. The results obtained with this kit were more favorable than those observed on Gram staining. The ODK0501 assay also showed a rapid reaction to the disappearance of S. pneumoniae in the sputum samples, while approximately 80% of the patients exhibited persistent positive results on the urinary antigen detection tests at the end of treatment. CONCLUSIONS: The ODK0501 test is a noninvasive, rapid and accurate tool for diagnosing respiratory infections caused by S. pneumoniae, although good quality sputum must be obtained prior to adequate treatment with antibiotics.

Urine antigen tests for the diagnosis of respiratory infections: legionellosis, histoplasmosis, pneumococcal pneumonia.

Urinary antigen testing has grown in popularity for several significant respiratory infections, particularly Legionella pneumophila, Streptococcus pneumoniae, and Histoplasma capsulatum. By capitalizing on the concentration of shed antigen from a variety of pathogens in the kidneys for excretion in the urine, urinary antigen testing can be used to obtain rapid test results related to respiratory infection, independent of an invasive collection such as a bronchoalveolar lavage. This article describes the 3 aforementioned organisms, their role in respiratory disease, and the current status of urinary antigen testing in their respective diagnosis.

Prevalence of human papillomavirus infection in the oropharynx and urine among sexually active men: a comparative study of infection by papillomavirus and other organisms, including Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma spp., and Ureaplasma spp.

BACKGROUND: Oropharyngeal squamous cell carcinoma (OSCC) has shown a gradual increase in male predominance due to the increasing incidence of human papillomavirus (HPV)-associated OSCC. However, the mode of HPV transmission to the oral cavity is poorly understood, and little is known about the epidemiology of oral HPV infection in men. The prevalence rates of HPV, Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma spp., and Ureaplasma spp. were compared in the oropharynx (oral cavity) and urine of male Japanese patients attending a sexually transmitted disease clinic. METHODS: The study population consisted of 213 men aged 16 - 70 years old (mean: 34.4 years old). Oropharyngeal gargles and urine were collected, and sedimented cells were preserved in liquid-based cytology solution. After DNA extraction, ß-globin and infectious organisms were analyzed by a PCR-based method. The HPV genotype was determined by HPV GenoArray test. RESULTS: ß-Globin was positive in 100% and 97.7% of oral and urine samples, respectively. HPV detection rates were 18.8% and 22.1% in oral and urine samples, respectively, suggesting that the prevalence of HPV infection in the oral cavity was similar to that in the urinary tract. N. gonorrhoeae was more prevalent in oral (15.6%) than urine samples (9.1%), whereas C. trachomatis was detected more frequently in urine (15.9%) than oral samples (4.2%). The detection rates of M. genitalium, M. hominis, and Ureaplasma spp. were 5.2%, 10.3%, and 16.0% in oral samples, and 7.7%, 6.3%, and 19.2% in urine, respectively. There were no significant differences in the detection rates of Mycoplasma spp. and Ureaplasma spp. between anatomical locations. The distribution of HPV types were similar in oral and urine samples, and HPV16 was the most common type. The majority of men with HPV infection in both the oral cavity and urine had concordant oral and urinary HPV infection. The presence of urinary HPV infection was an independent risk factor of oral HPV infection, with an odds ratio of 3.39 (95% CI: 1.49 - 7.71), whereas oral gonococcal infection was inversely correlated with oral HPV infection (odds ratio: 0.096; 95% CI: 0.01 - 0.77). CONCLUSIONS: Oral HPV infection commonly occurs in sexually active men, and is significantly correlated with urinary HPV infection.

Staphylococcal pyrogenic toxins in infant urine samples: a possible marker of transient bacteraemia.

AIM: To screen infant urine for staphylococcal pyrogenic toxins as a possible marker for a toxigenic, transient bacteraemia. METHODS: Nasopharyngeal swabs, skin swabs, stool and urine samples were collected from 30 infants at 2 weeks, 10 weeks and 7 months of age when the infants were healthy, and from infants of 7 months of age when they had a cold. Samples were cultured and Staphylococcus aureus isolates identified. Isolates were tested for the production of staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC) and toxic shock syndrome toxin (TSST-1). Urine samples were analysed for the presence of these toxins by ELISA. RESULTS: Nasopharyngeal carriage of S aureus decreased with age from 50% at 2 weeks of age to 13% in healthy infants at 7 months of age. Carriage was increased in infants over 7 months of age with a cold (36%). Stool carriage remained constant (37-40%) in healthy infants but increased significantly in infants over 7 months of age with a cold (82%). 13.9% of the isolates produced SEB, 16.7% produced SEC and 18% produced TSST-1. Some isolates produced more than one toxin. 43% of infants were colonised at some time with a toxigenic S aureus strain. S aureus toxins were detected in 9/101 urine samples. The proportion of positive samples was increased with infection and at 10 weeks of age. CONCLUSIONS: Infants are exposed early in life to S aureus pyrogenic toxins, which can be detected in infant urine samples. Age and infection affect the proportion of positive samples. The pattern of results can be explained by episodes of transient bacteraemia.

Relationships between cotinine, lower respiratory tract infection, and eosinophil cationic protein in children.

INTRODUCTION: The aim of this study was to investigate the effect of passive smoking on urine eosinophil cationic protein (u-ECP) in children with lower respiratory tract infections (LRTI). METHOD: This was a case-control study. The study cohort consisted of 150 children with LRTI (case group) and 150 healthy children (control), all from a urban setting. The statistical parameters were: a minimum of 139 children for a 95% confidence interval (95% CI), 80% power, and a possible exposure prevalence of 50%. The u-cotinine and u-ECP levels were measured by radioimmunoassay and fluoroimmunoassay methods, respectively. Data were analyzed by the McNemar chi-square test, t-test, and Pearson correlation. RESULTS: When the generally accepted cut-off level of 30 ng/mg urinary cotinine/creatinine was applied, 87.3% of the children with LRTI and 84.7% of healthy children were passive smokers. Using a cut-off level of 60 ng/mg, passive smoking increased the prevalence of LRTI by 4.7-fold (p=0.000). The mean u-ECP values were significantly higher in the case group than in the healthy control group (p=0.018). A positive association was found between u-cotinine and u-ECP values in children with LRTI (p=0.034). CONCLUSION: The results of this study indicate that passive smoking may play an important role in the development of respiratory infections and can cause airway inflammation in children with existing LRTI.

[Evaluation of infants and younger children passive smoking at home and prevalence of their lower respiratory tract infectious]. / Ocena narazenia niemowlat i dzieci mlodszych na bierne palenie tytoniu w srodowisku domowym w odniesieniu do czestosci wystepowania u nich zapalen dolnych dróg oddechowych.

The nicotine's metabolites were determined in urine of 92 children--59 children of smoking parents (SP) and 33 of non-smoking parents (NSP). The level of metabolites of nicotine and the ratio of the nicotine's metabolites to creatinine concentration were analyzed in infants (older than 5 months) and children 2-4 years old. Moreover the frequency of bronchitis and pneumonia in children was estimated on the basis of the interview with their parents. The nicotine's metabolites concentration was significantly higher in urine of children of SP than in urine of NSP children, as well in the group of infants as in children aged 2 to 4 years. Respiratory tract infections were frequent in 69.4% of SP children and in 21.1% of NSP children. In addition, the mean and the highest level of metabolites of nicotine in urine of SP children were multiple higher in comparison to the levels found in the group of NSP children suffering from the respiratory tract infections with equal frequency.

The uristatin dipstick is useful in distinguishing upper respiratory from urinary tract infections.

BACKGROUND: We determined the diagnostic value of the trypsin inhibitor, uristatin, that is commonly found in urine and plasma in patients with infections or inflammations of any kind. METHODS: We collected urine specimens from patients with infections of the urinary or upper respiratory tract and from healthy controls. We also collected blood from patients with a likely upper respiratory tract infection and healthy controls. A bacterial count of >10(5) organisms/ml in urine was considered to represent infection rather than contamination. RESULTS: The uristatin dipstick test in urine showed acceptable negative predictive values (NPV of up to 93%) for patients without infection or inflammation. Here, the dipsticks could eliminate some urine cultures. For those with infection or inflammation, the positive predictive values (PPV) of the dipsticks were lower (up to 57%). Including the leukocyte esterase and nitrite values increased the PPV of the dipsticks for those with disease. CONCLUSIONS: The uristatin strip was more accurate than the leukocyte and nitrite dipsticks for predicting upper respiratory infections (URI) and C-reactive protein for those with infection or inflammation. The uristatin dipstick was able to detect both the bikunin and uristatin inhibitors.

Pharmacokinetics of ciprofloxacin as a tool to optimise dosage schedules in community patients.

OBJECTIVE: To evaluate the dosage regimens of ciprofloxacin prescribed for outpatients by applying the principles of antibacterial therapy. DESIGN: Retrospective analysis of prescription and demographic data. SETTING: Community pharmacy in Valladolid, Spain. PATIENTS: Fifty male and female patients aged 18-93 years and with bodyweight 41-95kg. METHODS: Prescribed dosage regimen, age, weight, height, type of infection, comorbidity and coadministered drugs were recorded for each patient. Plasma concentration curves were simulated from literature values of the pharmacokinetic parameters of the drug and the age and weight of the patients. Urine concentrations were estimated from simulated plasma concentrations, literature values of renal clearance and an average urinary flow rate of 2 L/day. The potential efficacy of the prescribed treatment was evaluated from the ratio of the simulated peak plasma concentration (C(max)) to the literature value of the minimum inhibitory concentration (MIC) for the bacterium most probably responsible for the infection (C(max) /MIC). The ratio of area under the plasma concentration-time curve over 24 hours to MIC (AUC24 /MIC) was also estimated for non-urinary infections. RESULTS: Demographic variables such as age or bodyweight do not seem to be taken in consideration when ciprofloxacin is prescribed, at least in the patients considered here, leading to wide interindividual variability in plasma concentrations. This may not be relevant for urinary infections, since ciprofloxacin concentrates in the urine, leading to high Cmax /MIC ratios in all patients. Simulated plasma concentration-time curves revealed consistent underdosing for systemic infections in young patients over 60kg, for whom the plasma concentrations achieved led to Cmax /MIC and AUC24 /MIC ratios lower than those associated with clinical efficacy and minimal spread of bacterial resistance. CONCLUSIONS: The standard regimen of ciprofloxacin 250mg every 12 hours prescribed for urinary infections may not be the best choice, since a more convenient regimen of 500mg once daily leads to a higher Cmax /MIC ratio, which is associated with a more significant postantibiotic effect and higher efficacy of fluoroquinolones. For non-urinary infections, the age and weight of patients should be taken into account to achieve optimum plasma concentrations.

Observations on the possible origin of Mycoplasma fermentans incognitus strain based on antibiotic sensitivity tests.

Mycoplasma fermentans (incognitus strain), isolated during transfection studies in NIH/3T3 cells with DNA extracted from Kaposi's sarcoma tissue from a patient suffering from AIDS, showed high levels of resistance to numerous aminoglycoside antibiotics (MICs > 250 to > 500 mg/L) and in this respect matched the aminoglycoside resistance patterns of M. fermentans strains isolated recently from tissue culture cells. Two M. fermentans strains isolated from urine deposits from AIDS patients, without the use of cell cultures, and six M. fermentans isolates from patients with acute respiratory infections differed markedly from the incognitus strain, in that they were sensitive to aminoglycosides (MIC range 0.25-25 mg/L). A much older strain (K7) isolated from leukaemic bone marrow tissue in the 1960s, with the aid of cell cultures, was resistant to streptomycin (MIC > 250 mg/L) but sensitive to other aminoglycosides (MIC range 0.625-6.25 mg/L). These results suggest that, although the aminoglycoside-resistance in M. fermentans incognitus could have developed during the isolation process or through treatment of the AIDS patient with aminoglycosides, in view of the unusual manner in which the strain was isolated, its multiple aminoglycoside resistance and the fact that other M. fermentans strains isolated from AIDS patients, without the use of tissue culture cells, were aminoglycoside-sensitive, it is more likely that it was a tissue culture contaminant.

Serological study of responses to selected pathogens causing respiratory tract infection in the institutionalized elderly.

In a prospective 2-year study, serological responses to selected pathogens were analyzed in 224 episodes of fever attributable to respiratory tract infection (51.8%) or of unknown source (48.2%) in 131 residents of two long-term-care facilities. A serological response was identified in 45 episodes (20.1%): Chlamydia pneumoniae (14 episodes), Haemophilus influenzae type b (1), influenza virus type A (14), respiratory syncytial virus (RSV;2), parainfluenza virus type 3 (7), C. pneumoniae and H. influenzae (3), C. pneumoniae and influenza virus type A (2), C. pneumoniae and RSV (1), and C. pneumoniae and parainfluenza virus type 3 (1). No serological responses to Chlamydia psittaci, Chlamydia trachomatis, parainfluenza virus types 1 and 2, influenza virus type B, or Mycoplasma pneumoniae were seen. Vaccination did not affect the duration of fever in those residents with serologically confirmed influenza A. Serologically confirmed C. pneumoniae infection was detected in 9.4% of all febrile episodes. Serological responses to a second agent were detected in 33% of the patients with C. pneumoniae infections, and these dual infections were associated with an underlying malignancy (P = .02). C. pneumoniae should be recognized as a potential pathogen when choosing empirical antimicrobial therapy for respiratory tract infection in residents of long-term-care facilities.

Cigarette smoke exposure and development of infants throughout the first year of life: influence of passive smoking and nursing on cotinine levels in breast milk and infant's urine.

The effects of smoke exposure via mothers' milk and/or via passive smoking during the first year of life were investigated in a prospective longitudinal matched-pair study. The somatic and mental development of 69 infants whose mothers smoked more than five cigarettes per day throughout pregnancy and continued smoking after childbirth were compared with 69 children of non-smoking mothers. At birth, mean body weight of neonates from smoking mothers was significantly lower than the weight of neonates from non-smoking mothers. This weight difference between the two groups was no longer significant in infants at 12 months of age. With the methods employed by the authors, neither psychomotor nor mental development was affected by smoke exposure during pregnancy and early infancy. Infections of the lower respiratory tract were more frequent in the children of smoking mothers. These mothers weaned their babies earlier than non-smokers, but the different feeding behaviour did not influence any of the clinical parameters that were investigated in this study. In order to evaluate the extent of smoke exposure, cotinine was measured in children's urine and in breast milk once a month throughout the first year of life. Cotinine in the urine was significantly dependent on feeding behaviour: infants breast fed showed concentrations 10-fold higher than those who were bottle fed. Cotinine excretion in urine of infants from smoking mothers, who were not breast fed (nicotine exposure via passive smoking only) was even higher than that of adult passive smokers. If infants from smoking mothers were breast fed, their urinary cotinine excretion was in the range of adult smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

[Etiology of acute infections of the lower respiratory tract in hospitalized infants: bacterial antigens]. / Etiología de las infecciones agudas del tracto respiratorio bajo en lactantes hospitalizados: antígenos bacterianos.

Demonstration of bacterial antigens in biological fluids has been used for early detection of bacterial infections. Recent evidence suggests that higher detection rates of these antigens can be obtained from concentrated urine than from serum samples of patients. Evidence of bacterial infection by antigen detection was looked for from 50 fold concentrated urine samples by means of an ultrafilter system (Minicom) and latex agglutination for Haemophilus influenzae B (HiB) and Streptococcus pneumoniae (Sp) in three groups of patients. Group A (Positive controls), included 7 patients whose blood culture were positive for HiB (n = 5) and Sp (n = 2). Group B (Healthy controls) involved 16 children without clinical and laboratory signs of infection, coming from ambulatory well baby clinics and surgical wards, and group C was formed by 77 patients with negative blood cultures but with clinical and X ray evidence of lower respiratory tract infection. The corresponding antigen was demonstrated in urine samples from all group A patients. Three group B subjects gave positive results for HiB antigen. HiB antigen was detected from 10 and Sp antigen from 2 group C patients. These results suggest that the search for bacterial antigens in urine would be useful for etiological diagnosis and management of patients with bacterial pneumoniae. There is no definite explanation for the finding of HiB antigen in urine from apparently healthy children but the possibility of previous or actual asymptomatic infections must be taken into account.

Self-treatment with antibiotics.

Two hundred seventy patients who presented with symptoms assumed to be infectious in origin were evaluated for self-treatment with antibiotics. Urine was tested for the presence of antimicrobials by agar diffusion assay using Bacillus subtilis as the test organism. Seventeen patients (6%) were found to have antibiotic activity in their urine, but only five admitted to self-medication. Age, sex, and duration of symptoms were unrelated to the incidence of self-medication. Self-medication was seen more frequently in patients presenting with upper respiratory infection symptoms (12%) when compared to other symptom complexes (P less than .002). This study suggests that self-medication with antibiotics can be an important problem in patients who present to emergency departments, as this practice could have an impact on clinical diagnosis and bacterial cultures.

Pathogens associated with acute lower respiratory tract infection in young children.

To determine the agents associated with acute lower respiratory infection in young children, we studied 102 hospitalized children less than 5 years old using culture and serology for viruses and Chlamydia trachomatis, fluorescent antibody testing for pertussis and respiratory syncytial virus, blood cultures and counterimmunoelectrophoresis of nasopharyngeal secretions and urine for pneumococcal and Haemophilus influenzae type b antigens. At least one agent was detected in 87 children and multiple agents were found in 33. Viruses were detected 80 times; respiratory syncytial virus was most common (61 cases) and was detected as often by fluorescent antibody testing as by culture. C. trachomatis was detected in 10 children; all were less than 4 months old and 9 had mixed infections. Bacteria were detected 32 times, were usually pneumococcus (23) or H. influenzae (5) and were detected more often by counterimmunoelectrophoresis than by blood culture. Compared with children yielding only C. trachomatis or viruses, those with bacteria were significantly more likely to have fever, a band count over 2000/mm3 and radiographic consolidation. In this study acute lower respiratory infection was associated commonly with viruses, often with multiple pathogens but not with C. trachomatis after 4 months of age.