Diagnostic value of different laboratory methods in the diagnosis of pneumonia caused by Haemophilus influenzae type B

Comparative analysis of the diagnostic value of different laboratory methods in the diagnosis of H. influenzae b (Hib) pneumonia in children (bacteriological method, latex agglutination, counter immunoelectrophoresis, the passive hemagglutination test and the enzyme immunoassay (EIA) was carried out. EIA proved to be the most informative method for the diagnosing Hib pneumonia. EIA makes it possible to detect specific Hib antigens in different clinical materials in 48.8% of cases, as well as high titers of antibodies to mis infective agent in 61.7% of cases. The authors propose the unified criteria of the laboratory diagnosis of Hib infection in children.     

A Systematic Review on the Diagnosis of Pediatric Bacterial Pneumonia: When Gold Is Bronze

Background

In developing countries, pneumonia is one of the leading causes of death in children under five years of age and hence timely and accurate diagnosis is critical. In North America, pneumonia is also a common source of childhood morbidity and occasionally mortality. Clinicians traditionally have used the chest radiograph as the gold standard in the diagnosis of pneumonia, but they are becoming increasingly aware that it is not ideal. Numerous studies have shown that chest radiography findings lack precision in defining the etiology of childhood pneumonia. There is no single test that reliably distinguishes bacterial from non-bacterial causes. These factors have resulted in clinicians historically using a combination of physical signs and chest radiographs as a ‘gold standard’, though this combination of tests has been shown to be imperfect for diagnosis and assigning treatment. The objectives of this systematic review are to: 1) identify and categorize studies that have used single or multiple tests as a gold standard for assessing accuracy of other tests, and 2) given the ‘gold standard’ used, determine the accuracy of these other tests for diagnosing childhood bacterial pneumonia.

Methods and Findings

Search strategies were developed using a combination of subject headings and keywords adapted for 18 electronic bibliographic databases from inception to May 2008. Published studies were included if they: 1) included children one month to 18 years of age, 2) provided sufficient data regarding diagnostic accuracy to construct a 2×2 table, and 3) assessed the accuracy of one or more index tests as compared with other test(s) used as a ‘gold standard’. The literature search revealed 5,989 references of which 256 were screened for inclusion, resulting in 25 studies that satisfied all inclusion criteria. The studies examined a range of bacterium types and assessed the accuracy of several combinations of diagnostic tests. Eleven different gold standards were studied in the 25 included studies. Criterion validity was calculated for fourteen different index tests using eleven different gold standards. The most common gold standard utilized was blood culture tests used in six studies. Fourteen different tests were measured as index tests. PCT was the most common measured in five studies each with a different gold standard.

Conclusions

We have found that studies assessing the diagnostic accuracy of clinical, radiological, and laboratory tests for bacterial childhood pneumonia have used a heterogeneous group of gold standards, and found, at least in part because of this, that index tests have widely different accuracies. These findings highlight the need for identifying a widely accepted gold standard for diagnosis of bacterial pneumonia in children.     

Lung ultrasonography to diagnose community-acquired pneumonia in children

Background

Early diagnosis of community-acquired pneumonia (CAP) is essential to reduce the total burden of this disease. Traditionally, chest radiography (CR) is used to identify true CAP. However, CR is not a perfect diagnostic test for CAP. The use of lung ultrasonography (LUS) has been suggested as an alternative to overcome the problems associated with CR and increase the feasibility and accuracy of CAP diagnosis. LUS has largely been used for the diagnosis of several lung problems, including CAP, in adult patients with satisfactory results. Experience with LUS in children has grown over recent years. The main aim of this paper is to discuss the advantages and limits of LUS in the diagnosis of paediatric CAP.

Discussion

The presence of a consolidation pattern during LUS may represent pneumonia or atelectasis, although this conclusion is operator dependent. An overall agreement between LUS and CR was observed in most of the studies that were examined. In most reports where a disagreement between the two methods was found, CR was not able to identify the cases that were correctly diagnosed by LUS, particularly when CR was performed only with postero-anterior/antero-posterior projection and consolidation was observed in lung areas that are poorly visualized by CR. However, the lack of standardized LUS methods is problematic. Finally, the real advantage of LUS for the diagnosis of CAP in children remains unclear.

Summary

LUS is an interesting diagnostic modality that appears a useful first imaging test in children with suspected CAP. However, the methods used to perform LUS in children are not precisely standardized, and the diagnosis of interstitial CAP is inaccurate. Further studies are needed before LUS can be routinely used in everyday paediatric practice.

     

Latex agglutination test for diagnosing pneumococcal pneumonia in children in developing countries.

OBJECTIVE--To prepare and assess the sensitivity and specificity of a latex agglutination test specific for the serotype of antigen in diagnosing pneumococcal pneumonia in Gambian children. DESIGN--Comparison of agglutination test specific for serotype with culture of blood and lung aspirates, countercurrent immunoelectrophoresis, and commercial latex agglutination tests in diagnosing pneumococcal pneumonia. Cross reaction studies and investigation of 102 control children to determine specificity of agglutination test specific for serotype. SETTING--General medical ward of Medical Research Council laboratories, The Gambia. PATIENTS--101 Gambian children aged between 2 months and 10 years admitted with severe pneumonia. INTERVENTIONS--Serum samples were boiled and treated with edetic acid, and urine samples were boiled and concentrated 25 times before testing. END POINT--A latex agglutination test specific for the serotype of pneumococcal antigen that is sensitive and highly specific for detecting pneumococcus in the urine of patients with pneumococcal pneumonia. MEASUREMENTS AND MAIN RESULTS--Concentrated urine samples from 16 of the 21 children (76%) with pneumococcal pneumonia established by results of culture of blood or lung aspirates gave a positive result with the agglutination test specific for serotype, whereas only four of the 102 urine samples obtained from control children without pneumonia gave positive results. The serotypes of antigens detected in the urine of children with pneumococcal pneumonia and the serotypes of pneumococci isolated from cultures of blood or lung aspirates were the same in all cases. CONCLUSIONS--When performed on urine samples the agglutination test specific for serotype has a high specificity and is more sensitive than culture of blood or lung aspirates, commercial agglutination tests, or countercurrent immunoelectrophoresis in identifying pneumococcal pneumonia. It is easy to use and should be especially useful in communities with limited laboratory facilities.     

Specificity of the serological diagnosis of dysentery using erythrocytic reagents

The serological specificity of the diagnosis of dysentery, made by different methods with the use of antigenic and antibody erythrocyte diagnostic agents under the conditions of the circulation of different Shigella species and subspecies in a given locality, has been compared. The method for the determination of the diagnostic titer of the total serum antibody activity has proved to be the least specific. The methods for the detection of Shigella antigens, especially over time, in patients' excretions and for the determination of serum antibody activity show complete specificity. The combination of specificity and sensitivity makes the detection of Shigella antigens in feces by means of the passive hemagglutination test and the antibody neutralization test the method of choice for the diagnosis of dysentery.     

Use of the indirect immunofluorescence test in the diagnosis of an infection, caused by Mycoplasma pneumoniae

The indirect immunofluorescence test has been used for the serodiagnosis of M. pneumoniae infections in two paired blood sera of patients with acute respiratory diseases and acute pneumonia. The optimum methods for obtaining M. pneumonia antigen, its fixation and storage have been determined. The data on the study of the sensitivity, specificity and diagnostic value of the test are presented. The indirect immunofluorescence test has been shown to be capable of the simultaneous detection of complete (complement-binding) and incomplete (not binding the complement) antibodies to M. pneumoniae. This test may be used in the diagnostic practice as a highly sensitive, specific and sufficiently simple serological method.     

The 1952 Outbreak of Encephalitis in California (A Symposium): LABORATORY METHODS FOR ETIOLOGIC DIAGNOSIS

The general procedures used in the diagnosis of neurotropic viral diseases are outlined and are discussed with specific reference to western equine encephalitis.Cerebrospinal fluid is considered practically worthless as a starting material, in attempts to isolate the causal agent. The material of choice in attempting to recover the virus is central nervous system tissue, available only in instances of fatal infection. In the usual case, the diagnosis depends upon serologic or immunologic methods. These methods are aimed at detecting the presence of specific antibodies and of increases in the content of antibodies in the blood during the course of the illness.The in vitro complement fixation test is considered a better diagnostic tool than the in vivo neutralization test, since rises in titer are more readily detectable by the former technique than by the latter.     

The 1952 outbreak of encephalitis in California; laboratory methods for etiologic diagnosis

The general procedures used in the diagnosis of neurotropic viral diseases are outlined and are discussed with specific reference to western equine encephalitis. Cerebrospinal fluid is considered practically worthless as a starting material, in attempts to isolate the causal agent. The material of choice in attempting to recover the virus is central nervous system tissue, available only in instances of fatal infection. In the usual case, the diagnosis depends upon serologic or immunologic methods. These methods are aimed at detecting the presence of specific antibodies and of increases in the content of antibodies in the blood during the course of the illness. The in vitro complement fixation test is considered a better diagnostic tool than the in vivo neutralization test, since rises in titer are more readily detectable by the former technique than by the latter.     

Diagnosis of Corynebacterium pyogenes infection in pigs by immunodiffusion test with protease antigen.

A protease antigen was prepared from the culture supernatant of Corynebacterium pyogenes by concentrating with a flash evaporator and ultrafiltration. It was adjusted to the concentration of 32 units by the single radial immunodiffusion with a tentative standard serum. In the immunodiffusion test, the antigen of 4 units reacted enough with sera having an antibody titer ranging from 1 to 128. As a result, it was decided that the antigen of 4 units should be used in the immunodiffusion test for the detection of protease antibody. By the immunodiffusion test, protease antibody was demonstrated in about 35% of 443 sera from pigs collected at random. The antibody titer showed the distribution of 2 peaks. The summits of the two peaks were seen at 4 and 32 of antibody titer, respectively. The valley between the two peaks was seen at 16 of titer. From the result, a diagnostic criterion of the immunodiffusion test was decided provisionally as follows: above 16 of antibody titer is positive, 1 to 8 suspect, and less than 1 negative. On the other hand, protease antibody was demonstrated in sera from 13 of 14 pigs carrying abscesses from which C. pyogenes had been isolated. Its titer was 8 (in 2 pigs), 16 (in 1), 32 (in 3), 64 (in 6), and 128 (in 1). From these results, it was proposed that the immunodiffusion test with protease antigen be used for the diagnosis of C. pyogenes infection in pigs.     

Immunoenzyme method in the diagnosis of human brucellosis

The optimum conditions for the determination of specific antibodies in the sera of brucellosis patients by means of enzyme immunoassay (EIA) have been selected. The comparative study of the specificity and sensitivity of EIA and other serological tests has demonstrated that EIA has high diagnostic effectiveness in the diagnosis of acute and chronic brucellosis. The presence of direct correlation between the results of EIA and Coombs' test is observed, which is indicative of the capacity of EIA for detecting both complete and incomplete specific antibodies. It should be pointed out that in all cases the titer of specific antibodies in EIA has been found to be 5-16 times higher than in Coombs' test, the passive hemagglutination test, and agglutination test.     

Immunological diagnosis of Mycoplasma pneumonias]

A complex of immunological cell tests with M. pneumoniae antigen (the lymphocyte blast-cell transformation test, the allergic neutrophil alteration test) was carried out in order to establish the correlation between the results of positive seroconversion and the sepcific immunological reactivity of lymphoid cells in pneumonia patients. Mycoplasmic cutireactive allergen, when used for the accelerated diagnosis of mycoplasmic pneumonia in humans, was shown to be specific and safe. Cuti-allergic tests with mycoplasmic allergen allowed to diagnose mycoplasmic pneumonia at early stages (beginning from days 5--7), which ensures the possibility of indicating etiotropic treatment to patients in due time.     

Pneumonia in Indian and Eskimo Infants and Children: Part I. A Clinical Study

Ninety-seven Indian and Eskimo infants and children who suffered 112 episodes of pneumonia were the subjects of a prospective study carried out at the Charles Camsell Hospital, Edmonton, Alberta, from August 1963 until August 1964. Investigation included viral studies and an evaluation 10 days after admission. The patients were divided into four diagnostic categories and a comparison was made between cases of bacterial and viral origin. The frequency of right-sided disease, particularly of the upper lobe and/or dependent segment involvement, is described. An evaluation of physical signs is attempted. The problem of recurrent pneumonia and the differential diagnosis of tuberculosis in Indian and Eskimo children with pneumonia is discussed.     

Epidemiology and Diagnosis of Helicobacter pylori Infection

Medline, PubMed and the Cochrane databases were searched on epidemiology and diagnosis of Helicobacter pylori for the period of April 2011-March 2012. Several studies have shown that the prevalence of H.?pylori infection is decreasing in adults and children in many countries. Various diagnostic tests are available, and most of them have high sensitivity and specificity. The Maastricht IV/Florence consensus report states that the urea breath test using (13) C urea remains the best test to diagnose H.?pylori infection. Among the stool antigen tests, the ELISA monoclonal antibody test is recommended. All these tests were used, either as a single diagnostic test or in combination, to investigate H.?pylori infection among different populations throughout the world. Of particular interest, current improvements in high-resolution endoscopic technologies enable increased diagnostic accuracy for the detection of H.?pylori infection, but none of these techniques, at present, are specific enough for obtaining a real-time diagnosis of H.?pylori infection.     

Giant-cell pneumonia caused by measles and methotrexate in childhood leukaemia in remission.

Four children who had acurate lymphoblastic leukaemia in remission and developed pneumonia were studied. Investigations including electron microscopy and immunofluorescence of lung biopsy material disclosed measles, although there was no clinical evidence of the disease. Despite an identical presentation, two types of illness developed: two children died of giant-cell pneumonia, while the other two developed pneumonia indistinguishable from that associated with methotrexate treatment, recovering when treated with steroids and gammaglobulin. Measles infection is easily overlooked in the absence of rash. The diagnosis may be suggested by clinical and radiological features and confirmed by specific immunofluorescence staining of lung biopsy tissue.     

Lung ultrasound for the diagnosis of pneumonia in children with acute bronchiolitis

Background

Guidelines currently do not recommend the routine use of chest x-ray (CXR) in bronchiolitis. However, CXR is still performed in a high percentage of cases, mainly to diagnose or rule out pneumonia. The inappropriate use of CXR results in children exposure to ionizing radiations and increased medical costs. Lung Ultrasound (LUS) has become an emerging diagnostic tool for diagnosing pneumonia in the last decades. The purpose of this study was to assess the diagnostic accuracy and reliability of LUS for the detection of pneumonia in hospitalized children with bronchiolitis and to evaluate the agreement between LUS and CXR in diagnosing pneumonia in these patients.

Methods

We enrolled children admitted to our hospital in 2016–2017 with a diagnosis of bronchiolitis and undergone CXR because of clinical suspicion of concomitant pneumonia. LUS was performed in each child by a pediatrician blinded to the patient’s clinical, laboratory and CXR findings. An exploratory analysis was done in the first 30 patients to evaluate the inter-observer agreement between a pediatrician and a radiologist who independently performed LUS. The diagnosis of pneumonia was established by an expert clinician based on the recommendations of the British Thoracic Society guidelines.

Results

Eighty seven children with bronchiolitis were investigated. A final diagnosis of concomitant pneumonia was made in 25 patients. Sensitivity and specificity of LUS for the diagnosis of pneumonia were 100% and 83.9% respectively, with an area under-the-curve of 0.92, while CXR showed a sensitivity of 96% and specificity of 87.1%. When only consolidation >?1?cm was considered consistent with pneumonia, the specificity of LUS increased to 98.4% and the sensitivity decreased to 80.0%, with an area under-the-curve of 0.89. Cohen’s kappa between pediatrician and radiologist sonologists in the first 30 patients showed an almost perfect agreement in diagnosing pneumonia by LUS (K 0.93).

Conclusions

This study shows the good accuracy of LUS in diagnosing pneumonia in children with clinical bronchiolitis. When including only consolidation size >?1?cm, specificity of LUS was higher than CXR, avoiding the need to perform CXR in these patients. Added benefit of LUS included high inter-observer agreement.

Trial registration

Identifier: NCT03280732. Registered 12 September 2017 (retrospectively registered).

     

Serological Analysis by Enzyme-Linked Immunosorbent Assay Using Recombinant Antigen LipL32 for the Diagnosis of Swine Leptospirosis

Leptospirosis is an important global zoonotic disease caused by pathogenic Leptospira spp. species. Swine leptospirosis has a major economic impact because pigs are sources of animal protein and by-products. The signs of swine leptospirosis are abortion, stillbirth, birth of weak or ill piglets, appearing 14–60 days after infection. The reference method for diagnosis of leptospirosis is the microscopic agglutination test (MAT), in which serum samples are reacted with live antigen suspensions of leptospiral serovars. However, MAT is laborious and time consuming as a diagnostic procedure when dealing with a large number of samples; therefore, efforts are being made to develop novel, sensitive, and specific diagnostic tests for leptospirosis. In this study, a recombinant LipL32 based on enzyme-linked immunosorbent assay (rLipL32/ELISA) was evaluated as a screening test for the detection of pathogenic leptospiral-specific antibodies. A total of 86 swine serum samples tested by MAT were used to develop rLipL32/ELISA. Compared to positive and negative sera tested by MAT, rLipL32/ELISA showed 100 % sensitivity, 85.1 % specificity, and 91.86 % accuracy. No positive reaction for other bacterial diseases (enzootic pneumonia and brucellosis) was observed. The rLipL32/ELISA reported in this study is a specific, sensitive, and convenient test for the detection of antibodies against swine leptospiral infection and can be used as a rapid screening test in epidemiological surveys.     

小儿肺炎支原体的分离培养及其药敏试验分析

对356例小儿肺炎患者的咽拭子进行肺炎支原体(MP)分离培养并对9种抗生素进行药敏试验.结果显示,MP阳性55例,阳性率为15.4%,耐药性由高到低为罗红霉素(54.5%)>克拉霉素(32.7%)=阿奇霉素(32.7%)>红霉素(21.8%)=加替沙星(21.8%)>克林霉素(20.0%)>乙酰螺旋霉素(9.1%)>司...     

尿液分析及胸部X线筛查重度感染或者脓毒性休克感染源的回顾性分析

目的：评估重症监护室的重症感染或者脓毒性休克患者尿常规检查和胸部X线检查的准确性。方法：回顾性分析我院进入重症监护室的确诊为重症感染或者脓毒性休克的患者,收集所有入组患者的个人情况,进入监护室以后的尿液检查结果、胸部X线检查结果,以及体液细菌学培养的结果,分析上述数据与诊断泌尿系感染或者肺部感染之间关系。结果：我们回顾了400例患者,其中70例患者确诊为重症感染或者脓毒性休克,其中13例患者确诊为泌尿系感染（尿常规,白细胞〉10／高倍镜视野）,敏感性和特异性分别为81％（95％CI0．67-0．92）和65％（95％CI0．51—0．75）;36例患者确诊为肺部感染,胸部X线检查诊断肺部感染的的敏感性和特畀性分别为57％（95％C10．45—0．69）和92％（95％C10．82-0．93）。结论：对于脓毒血症或者脓毒性休克的患者,胸部X线检查敏感性较低,这可能与肺部X线检查干扰因素较多,并且肺部感染发生到出现影像学变化有一定的时间间隔：而尿液分析敏感性较高,但是也可能由于尿液中上皮细胞的存在而干扰诊断。     

CD4 T cell count as predictor of Pneumocystis carinii pneumonia in children born to mothers infected with HIV. European Collaborative Study Group.

OBJECTIVE--To assess the value of CD4 T cell count in predicting Pneumocystis carinii pneumonia in infants born to mothers infected with HIV, with reference to the guidelines from the Centers for Disease Control on prophylaxis against pneumocystis. DESIGN--Prospective birth cohort study. SETTING--Hospitals in 10 European cities participating in the European collaborative study. SUBJECTS--924 children born to mothers known to be infected with HIV at or before delivery. MAIN OUTCOME MEASURES--The incidence of P carinii pneumonia. CD4 T cell counts in children before diagnosis of the pneumonia. The proportions of children infected and uninfected with HIV who fulfilled the criteria for primary prophylaxis. RESULTS--Fourteen children were diagnosed with P carinii pneumonia. The cumulative incidence by the age of 6 years was 2% (95% confidence interval 0.9 to 3.0%). Of the 11 children with a CD4 T cell count predating diagnosis, only three fulfilled the criteria from the Centers for Disease Control for prophylaxis. Prophylaxis was indicated by 1 year of age for 62% of infected children who had not developed P carinii pneumonia and for at least 10% of uninfected children. CONCLUSIONS--Monitoring CD4 T cell count seems to be of limited value in deciding when to start prophylaxis against P carinii pneumonia in children born to mothers infected with HIV. The alternative approach of giving prophylaxis to all children born to infected mothers would be difficult to justify given the low incidence of the pneumonia.     

Circulating immune complexes in the diagnosis of Mycoplasma pneumoniae infection

The possibility of detecting M. pneumoniae antigen and antibodies to it, incorporated into immune complexes, in the sera of patients with acute pneumonia by means of erythrocyte diagnosticums was studied, and the immunological characterization of these complexes was made. In patients with mycoplasmal pneumonia M. pneumoniae antigen and specific antibodies, both free and incorporated into immune complexes, were found to circulate in the blood. In children, antigenemia was detected twice as frequently as in adults. Dissociated M. pneumoniae antigens had different molecular weight, their location on the gel chromatogram of the serum being in fractions 7S and 19S. The dissociation of immune complexes permits the detection of M. pneumoniae antigen and antibodies to it in a bound state by means of the passive hemagglutination test, thus increasing the frequency of positive results in the diagnosis of M. pneumoniae infection.