Comparison of the sensitivity of two methods for isolation of Mycoplasma pneumoniae.

Throat swab specimens from 1,494 Marine Corps recruits were inoculated into vials containing diphasic (broth/agar) mycoplasma medium and also onto PPLO agar plates, which were subsequently overlayed with sheep erythrocytes in saline agar. Strains of Mycoplasma pneumoniae were isolated from 89 (6%) of the specimens by one or both of the methods. Eight-one of the 89 (91%) positive specimens were cultured with diphasic medium, whereas only 42 (47%) were cultured with the overlay method (x2 = 7.44, P less than 0.01). The diphasic system for isolation of M. pneumoniae should be the method of choice in clinical and research application.     

Comparison of PCR for sputum samples obtained by induced cough and serological tests for diagnosis of Mycoplasma pneumoniae infection in children

Passive agglutination (PA) and immunoglobulin M (IgM), IgA, and IgG enzyme-linked immunosorbent assays (ELISAs) for the diagnosis of Mycoplasma pneumoniae were compared with PCR testing of sputum samples obtained from children with lower respiratory tract infections. The sensitivity and specificity of PA were 80.3% and 92.3% at a titer of 1:80. ELISA was found to be less sensitive than PA.     

Comparative studies of three serologic methods for the measurement of Mycoplasma pneumoniae antibodies

Antibodies against Mycoplasma pneumoniae in the sera of patients and normal adult controls were measured by a standard complement fixation (CF) test, a commercial immunofluorescence (IF) test (CROWNTITRE), and a commercial enzyme-linked immunosorbent assay (ELISA) (MYCOPLASMELISA). The findings showed that, in the control sera, 269 of 277 (97%) had negative results for CF antibodies. Of the 320 controls tested by the IF assay, all (100%) had negative results for IgM antibodies and 314 (98%) had negative results for IgG antibodies. Only 6 of the 201 (3%) controls by the ELISA were classified as negative/equivocal. Among the 450 patient sera, 105 (23%) had positive results for CF antibodies, and 158 (35%) had positive results for IgG and/or IgM membrane antibodies by the IF test; 424 of these patients' sera were also tested by the ELISA, and 397 (94%) of them were found to have positive results for anti-M. pneumoniae IgG antibodies. If the CF test were chosen as the standard for comparison, the IF test would have a sensitivity of 87% and a specificity of 81% and the ELISA would have a sensitivity of 71% and a specificity of 80%, provided an adjustment in the threshold ELISA-positive value was made. A single positive M. pneumoniae membrane IgM antibody titer appeared to be valuable for a presumptive diagnosis of an ongoing infection; 41 of 47 (87%) of the IgM-positive results in the paired sera were supported by a fourfold increase or a stable high level of CF antibody titer.     

Comparison of three serological methods for the detection of hepatitis-associated antigen

Serum hepatitis (Australia) antigen in the sera of hepatitis patients and carriers can be detected in one and a half to three hours by crossover electrophoresis. The method is more sensitive than the immunodiffusion technique commonly employed in this field. It is of the same order of sensitivity as complement fixation but is less complicated.Crossover electrophoresis is thus the method of choice for the rapid screening of sera for hepatitis antigen; complement fixation may be used for quantitative determination of antigen in positive cases.     

Comparative studies of serological test for Mycoplasma pneumoniae on 73 cases of lower respiratory infection disease

The purpose of this report is to evaluate a test kit based on the High Density Composite Particle Agglutination Test Method (HDPA method, Newly developed by Tokuyama Soda Co., Ltd). Diagnosis of Mycoplasmosis has been done with clinical symptoms, breast x-ray examination, serum anti-M. pneumoniae antibody detection and bacteriological test result. Recently, we had the chance to use this HDPA method (IMMUNOTICLES MYCO) and compared the results with bacteriological test, complement fixation method (CF) and particle agglutination method (PA) using the cases of seventy-three (73) lower respiratory infected patients. The evaluation outcomes (positive rate, sensitivities and specificities) comparing with the conventional methods based on the clinical cultured results and clinical diagnostic results respectively are shown as follows. 1) The evaluation outcomes based on the cultured results. Forty-one (41) cases of 73 samples, we could isolate the M. pneumoniae (56.2%). a) The HDPA method is correlated with CF (r = 0.885, n = 73) and PA (r = 0.764, n = 73) respectively. b) The positive rate of HDPA, PA and CF are 45.2%, 31.5% and 20.5% respectively. 2) The evaluation outcomes based on the clinical diagnosis. a) The sensitivity of the HDPA method is 66.0% and this one is much higher than the one of CF and PA. b) The specificity of the HDPA method is 92.3%. c) The positive rate of the HDPA method is higher than the one of PA and CF even though the assay was done within seven-days. In conclusion, the HDPA method is a very sophisticated method for diagnosis of M. pneumoniae and able to be substituted to any other conventional methods.     

Comparison of three tests for the serological diagnosis of lymphocytic choriomeningitis virus infection.

Levels of lymphocytic choriomeningitis virus antibody were assayed in 62 infected persons. The three tests used were indirect fluorescent antibody (IFA), complement fixation, and neutralization in mice. The sera first became positive by the IFA test, and IFA titers rapidly rose to a relatively high level, with the sera remaining positive long after the antibody detectable by complement fixation had disappeared. The IFA test appeared to be specific. The sera became positive last by the mouse neutralization test; with this test, antibody first appeared several weeks after infection. Virus-infected cells were stable when stored at -60 C, allowing diagnostic sera to be tested promptly by the IFA test. The IFA test for lymphocytic choriomeningitis antibody should increase the number of serological diagnoses, since it is not only rapid and specific, but detects cases not diagnosed by the other methods.     

The diagnostic value of serological studies in pediatric patients with acute Mycoplasma pneumoniae infection

BackgroundMycoplasma pneumoniae is a common pathogen of respiratory tract infections in pediatric patients. Serological studies are traditional methods for the diagnosis. However, early diagnosis of M. pneumoniae infections remains problematic. We investigate the value of early serum immunoglobulin A (IgA), in addition to immunoglobulin G (IgG), and immunoglobulin M (IgM) levels, in children infected with M. pneumoniae.MethodsFrom August 2016 to February 2017, we enrolled pediatric patients based on both clinical symptoms and chest x-ray, and confirmed by positive throat culture for M. pneumoniae. Serum titers of M. pneumoniae IgM, IgG, and IgA during the acute phase were checked. All respiratory samples were further analyzed by polymerase chain reaction (PCR). Diagnostic values of different tests were evaluated.ResultsFifty-six patients fulfilled the diagnostic criteria, with a median age of 4.84 years. Most of them (89.3%) were enrolled within 7 days of disease onset. PCR was positive in 71.4% of the study population. Early IgG samples were of limited value in diagnosing M. pneumoniae infection, of which 89.3% showed a negative result. Positive rates of early serum IgA and IgM were 48.2% and 46.4%, respectively. In combination with IgA and/or IgM, the sensitivity increased to 71.4% during their early clinical course.ConclusionsIn the pediatric population, combined serological tests of M. pneumoniae IgA and IgM, offer an accurate method of early diagnosis comparable to that of PCR, and can be an alternative choice for prompt detection of mycoplasma infections when PCR and culture are not available.     

Comparison of specific serological assays for diagnosing human herpesvirus 6 infection after liver transplantation

Cross-reactivity between human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) antibodies and the reliability of specific serological assays were analyzed for 12 patients with concurrent HHV-6 and HHV-7 antibody responses after transplantation with a liver from a living relative by using an immunofluorescence assay (IFA). A neutralizing antibody titer assay (NT) and an immunoblot assay (IB) designed to detect immunoglobulin M (IgM) antibody to the HHV-6 immunodominant 101-kDa protein were compared in the diagnosis of an active HHV-6 infection. A total of 9 of 12 patients demonstrated concurrent HHV-6 and HHV-7 antibody responses, including increased IgG titers and/or the presence of IgM by IFA, and were thus analyzed for cross-reactive antibody to heterologous virus. The average percentages of residual antibody to HHV-6 and HHV-7 after absorption with HHV-6 antigen were 32.6% (range, 6 to 50%) and 55.6% (range, 35 to 100%), respectively. All 12 patients were subsequently analyzed for HHV-6 antibody by using IB and NT. IB detected IgM antibody to the 101-kDa protein in 75% (9 of 12) of the recipients. A significant rise in the NT antibody titer was detected in the same nine samples. However, HHV-6 DNA was detected by PCR in only five of nine plasma samples collected from recipients with a specific serologic response against HHV-6.     

Comparison of Gen-Probe commercial kit and culture technique for the diagnosis of Mycoplasma pneumoniae infection.

The Gen-Probe rapid diagnostic system was compared with a culture method for the detection of Mycoplasma pneumoniae in clinical specimens. Of 116 clinical specimens, 103 (88.8%) yielded identical results. The relative sensitivity and specificity of the probe were both 89%. Rapid turnaround time and its sensitivity and specificity indicate that the probe test is a practical method for the rapid diagnosis of M. pneumoniae infections.     

Smooth muscle antibodies in Mycoplasma pneumoniae infection.

Paired sera from forty-five cases of Mycoplasma pneumoniae (MP) infection associated with acute lower respiratory tract illness were examined by immunofluorescence for antibodies to smooth muscle. Twenty-five (56%) of these cases had smooth muscle antibodies (SMA) of IgM class. A significant (greater than or equal to 4-fold) increase in titre of these antibodies was demonstrated in fifteen of thirty-five patients with a significant rise in titre of MP antibodies. SMA of IgG class occurred in eleven of forty-five cases (24%), but a 4-fold rise in antibody titre was found only in two cases. Three of forty-five sera (7%) from healthy donors contained SMA of IgM class and eight sera (18%) SMA of IgG class. MP antigen did not absorb SMA. Liver tests were performed in twenty-nine patients. In eighteen patients SGPT values were moderately or slightly elevated. There was no correlation between the occurrence of increased levels of transaminases and the presence of SMA in serum. In a patient with active chronic hepatitis, who had had a high titre of SMA exclusively of IgG class for 2 years, SMA of IgM class appeared transiently in association with an acute respiratory illness due to MP.     

CT诊断重症肺炎支原体肺炎的价值

目的:研究电子计算机断层扫描（CT）诊断重症肺炎支原体肺炎（SMPP）的价值。方法:50例SMPP患者均接受X线和CT检查,比较两种诊断方法的确诊率和误诊率。观察X线和CT诊断的影像学表现。结果:CT检查组确诊率显著高于X线组（94.00% vs 72.00%, P<0.05）,CT检查组误诊率显著低于X线组（6.00% vs 28.00%, P<0.05）。结论:CT诊断SMPP确诊率较高,误诊率较低,能够清晰反映患者混合性病症和支气管病变,具有较高的临床参考价值。     

Parameters of Mycoplasma pneumoniae infection in Syrian hamsters.

An animal model for evaluating the potency of Mycoplasma pneumoniae vaccines was developed with hamsters. Factors that influence hamster infection by M. pneumoniae were defined, and parameters for assessment of intensity of pulmonary disease were established. Colonization of hamster lungs was determined by culture, and intensity of lung disease was assessed histopathologically and expressed numerically as a lung pathological score. Intratracheal inoculation of the challenge was superior to the intranasal or aerosol route for inducing a consistent degree of lung disease. A challenge dose of 10(6) CFU inoculated intratracheally produced lung colonization and significant reproducible lung pathological scores in essentially all unvaccinated animals. The peak of infection, as determined by these criteria, was at about 2 weeks after challenge. Animals over 6 weeks of age were preferable for the test, since younger animals exhibited a lower lung pathological score even though they showed the same degree of lung colonization. The hamster assay developed provides a dependable experimental system for testing the protective potency of M. pneumoniae vaccines.     

Efficiency of various serological techniques for diagnosing Coxiella burnetii infection

An indirect immunofluorescence assay (IFA) using a recently developed commercial kit for detecting antibodies against Coxiella burnetii (C.b.), the etiological agent of Q fever, has been evaluated using human field serum samples. The IFA was compared with an ELISA and a complement fixation test (CFT). The IFA was based on the corpuscular C.b. phase I and phase II antigens specific to anti-C.b. phase I and II antibodies, respectively. Fifty sera from persons with symptoms of Q fever were examined in this study. The IFA compared with the ELISA showed the sensitivities of 97.7% and 87.2% for IgG and 66.7% and 60.0% for IgM phase II and I antibodies, respectively and the specificities of 100% and 90.0% for IgG and 75.9% and 64.7% for IgM phase II and phase I antibodies, respectively. Due to a limited number of sera positive in the IgA antibody testing, the data presented should be considered with caution. It appears that the IFA strikes a very good balance between high specificity and sensitivity with phase II and phase I IgG antibodies and a less satisfactory one with IgM antibodies. The CFT failed in one of the above aspects showing a good specificity but a poor sensitivity, especially for phase I antibodies. The study demonstrated that the IFA is suitable for diagnosing Q fever and its therapeutic follow-up and is a good candidate for screening sera in large numbers. A certain limitation, especially in testing early stages of the chronic disease, could be a low fluorescence intensity of the IgA positive control in comparison with the IgA negative one.     

Comparison of host responses after intranasal infection of guinea-pigs with Mycoplasma genitalium or with Mycoplasma pneumoniae

Guinea-pigs were infected intranasally with Mycoplasma genitalium or Mycoplasma pneumoniae. The lung lesions produced by the two mycoplasmas were comparable in extent and histological pattern. Sera of both animal groups taken 2 weeks after infection reacted strongly in the complement fixation test with the M. pneumoniae glycolipid extract. In an ELISA using the respective adherence proteins (P1-protein of M. pneumoniae and MgPa of M. genitalium), strong specific activity, but also considerable cross-reactions were found. Epitope analysis by using overlapping octapeptides of a P1-region immunologically active in human M. pneumoniae infections and of the corresponding MgPa-region revealed six common epitopes but also one M. genitalium and two M. pneumoniae specific determinants. For analysis of a possible pathogenicity of M. genitalium in the human respiratory tract species-specific tests have to be developed.     

Acute respiratory infection due to Mycoplasma pneumoniae: current status of diagnostic methods

Because of the absence of well-standardized both in-house and FDA-approved commercially available diagnostic tests, the reliable diagnosis of respiratory infection due to Mycoplasma pneumoniae remains difficult. In addition, no formal external quality assessment schemes which would allow to conclude about the performance of M. pneumoniae diagnostic tests exist. In this review, the current state of knowledge of M. pneumoniae-associated respiratory infections in the context of epidemiological studies published during the past 5 years is discussed, with particular emphasis on the diagnostic strategies used and their impact on results. The role of M. pneumoniae as a cause of respiratory tract infections (RTIs) differs from study to study due to geographical and epidemiological differences, as well as to the application of different diagnostic techniques and criteria used.     

Evaluation of an indirect haemagglutination kit for the rapid serological diagnosis of Mycoplasma pneumoniae infections.

A recently introduced indirect haemagglutination kit for the detection of Mycoplasma pneumoniae antibodies is compared with the standard method complement fixation. It is concluded that the kit provides a rapid, simple, and moderately sensitive means of detecting antibodies and, in some cases, enables these to be detected in the early, acute stage of infection.     

Serological diagnosis of Mycoplasma pneumoniae infection by enzyme immunoassay.

Antibodies against Mycoplasma pneumoniae antigen obtained by Tween-ether treatment from purified M. pneumoniae were measured by means of enzyme-linked immunosorbent assay (ELISA). Paired sera from 19 patients with pneumonia and from 13 patients with acute pancreatitis with a significant rise in complement fixing antibodies against M. pneumoniae were studied. Single sera from healthy 1-year-old children were used as controls. High levels of IgG and IgM class antibodies were seen in sera from patients with pneumonia while most patients with acute pancreatitis and all the children showed low levels of antibodies. The results indicate that ELISA using Tween-ether treated M. pneumoniae antigen could be used successfully in the specific laboratory diagnosis of M. pneumoniae infection.