Typing of Haemophilus influenzae by Coagglutination and Conventional Slide Agglutination

Coagglutination was compared with conventional slide agglutination for the typing of 297 clinical isolates of Haemophilus sp. A 100% correlation was found with the H. influenzae type b isolates. Coagglutination showed no false-positive reactions with the nontypable strains of H. influenzae and H. parainfluenzae isolates; however, conventional slide agglutination exhibited many false-positive and non-interpretable reactions.     

Rapid Detection of Methicillin Resistance in Staphylococcus aureus Isolates by the MRSA-Screen Latex Agglutination Test

The slide agglutination test MRSA-Screen (Denka Seiken Co., Niigata, Japan) was compared with the mecA PCR ("gold standard") for the detection of methicillin resistance in Staphylococcus aureus. The MRSA-Screen test detected the penicillin-binding protein 2a (PBP2a) antigen in 87 of 90 genetically diverse methicillin-resistant S. aureus (MRSA) stock culture strains, leading to a sensitivity of 97%. The three discrepant MRSA strains displayed positive results only after induction of the mecA gene by exposure to methicillin. Both mecA PCR and MRSA-Screen displayed negative results among the methicillin-susceptible S. aureus strains (n = 106), as well as for Micrococcus spp. (n = 10), members of the family Enterobacteriaceae (n = 10), Streptococcus pneumoniae (n = 10), and Enterococcus spp. (n = 10) (specificity = 100%). Producing the same PBP2a antigen, all 10 methicillin-resistant Staphylococcus epidermidis strains score positived in both the latex test and the mecA PCR. Consequently, the MRSA-Screen test should be applied only after identification of the MRSA strain to the species level to rule out coagulase-negative staphylococci. In conclusion, due to excellent specificity and sensitivity the MRSA-Screen latex test has the potential to be successfully used for routine applications in the microbiology laboratory.     

Evaluation of the Recombigen HIV-1 Latex Agglutination Test.

The Recombigen HIV-1 Latex Agglutination (LA) Test was recently licensed by the U.S. Food and Drug Administration for use as a rapid screening assay for human immunodeficiency virus type 1 (HIV-1) antibodies. However, its performance in various settings and in different populations has not been firmly established. Consequently, we evaluated the test in the Cleveland Clinic Retrovirus Laboratory, a regional reference laboratory for HIV diagnostic testing and a testing laboratory for the Ohio Department of Health Anonymous HIV Testing and Counseling Program. Serum samples from 93 individuals presumed to be at high risk for HIV infection were evaluated. The sera were initially tested for HIV antibodies by enzyme-linked immunosorbent assay (ELISA). All repeatedly reactive sera were subjected to confirmatory Western blot (WB; immunoblot) testing. Of 97 serum specimens tested (5 were from one seroconverter), 44 were repeatedly reactive by ELISA and 53 were nonreactive. Of the reactive serum specimens, 31 were confirmed positive and 12 were indeterminate by WB. All of the sera were coded and then retested by the LA test. Of 53 serum specimens nonreactive by ELISA, 51 were also nonreactive in the LA test. Of the 44 serum specimens reactive by ELISA, 16 were nonreactive by LA; however, 3 of the latter were WB positive. No serum specimen with an ELISA ratio (specimen optical density/cutoff optical density) of less than 2.1 scored reactive in the LA test. The LA test was positive for only two of five consecutive serum specimens from a seroconverter despite the fact that all but the earliest of these were ELISA reactive and WB positive. Although the LA test appears to be an adequate first-line screening test when appropriately used according to the directions of the manufacturer, our data suggest that occasional sera with low levels of reactivity by ELISA may not be readily detected as reactive by the LA test.     

动物流畅性测验在中国老人中的应用

目的：分析动物流畅性测验（AFT）中12生肖知识在汉族正常老年人和认知障碍患者中的表现和本质。方法：512例正常老人、153例遗忘型轻度认知损害（aMCI）患者和124例阿尔茨海默病（AD）患者完成动物流畅性测验和其他一系列测验（如简明精神状态量表、听觉词语学习测验等）。结果：AFT总正确数和非生肖数与性别、受教育程度、病前智力、目前总体认知及记忆功能均有不同程度的相关（r=-0.107-0.311,P〈0.05或0.01）并达到统计学显著性。通过正常老人、aMCI和AD等不同认知障碍严重度的样本比较,生肖指标和非生肖指标的衰退模式不同。以“均数-1SD（标准差）”作为划界分,AFT总正确数指标识别AD的敏感性和特异性均为81%,非生肖数指标的敏感性为85%,提高了4个百分点（特异性相同）。结论：AFT的表现包括意识性提取与自动提取记忆成分。对汉语文化背景下AFT内部编码特征的深入研究,不仅可以提高痴呆识别的敏感性,而且对于记忆的理论研究也有一定的启发和意义。     

Isolation of bacteria which could perform nitrification and denitrification simultaneously by gene probe

The bacteria which could perform nitrification and denitrification simultaneously from nitrogen containing wastes in Taiwan were isolated by using the probes made from random DNA fragments of Thiosphaera pantotropha. Two isolates were identified and named Alcaligenes faecalis subsp. faecalis strain 1 and strain 2 respectively. The effects on nitrification and denitrification by different medium pH, oxygen content, addition of different electron donors or inhibitors were studied. The isolates not only could perform nitrification, but also denitrification even in the presence of oxygen. Potassium cyanide could inhibit denitrification; hydrazine and hydroxyamine could inhibit nitrification. Alcaligenes faecalis subsp. faecalis strain 2 shows better denitrification.     

Detection of Antibodies to Babesia equi in Horses by a Latex Agglutination Test Using Recombinant EMA-1

A latex agglutination test (LAT) using recombinant equi merozoite antigen 1 (EMA-1) for the detection of antibodies to Babesia equi was developed. The LAT was able to differentiate very clearly between sera from B. equi-infected horses and sera from Babesia caballi-infected horses or from normal horses. The LAT results were identical to those of a previously developed enzyme-linked immunosorbent assay. These results indicate that LAT using recombinant EMA-1 might be very useful as a routine screening method for the diagnosis of B. equi infection.     

Detection of Moulds in Food by Latex Agglutination: A Collaborative Study

The latex agglutination assay for detection of Aspergillus and Penicillium species in food products was tested by nine different laboratories. The test is a slide agglutination test which uses latex particles sensitized with immunoglobulins specific for extracellular polysaccharides (EPS) produced by species of Aspergillus and Penicillium. False positive results are recognized by use of sensitized latex particles, to which synthesized haptens have been added. These haptens, with an identical structure of the epitopes present on the EPS, specifically block the immunoglobulins present on the latex particles. False negative results are recognized by addition of EPS to test samples. Besides the latex agglutination assay, the collaborative laboratories used their own methods for detection of moulds in the food products. Eight of the nine laboratories applied the colony counting method for enumeration of moulds and in total seven different media were used. Using purified EPS, eight laboratories were able to detect a quantity ranging from 5–15 ng/ml. Of the different foods tested cereals, animal feed and spices showed fair correlation between mould colony count and latex agglutination titre. For other products, such as different fruit juices, a correlation was not observed. Of the different foods tested by the participating laboratories, walnuts gave clearly false positive results. The results of the collaborative study have shown that the latex agglutination is a rapid, simple and reliable quantitive method for detection of Penicillium and Aspergillus in cereals, spices and animal feeds.     

Rapid Slide Latex Agglutination Test for Detection of Methicillin Resistance in Staphylococcus aureus

The MRSA screen test (Denka Seiken Co., Ltd.), a commercially available, rapid (20-min) slide latex agglutination test for the determination of methicillin resistance by detection of PBP 2a in Staphylococcus aureus, was compared with the oxacillin agar screen test and PCR detection of the mecA gene. A total of 563 S. aureus isolates were tested. Two hundred ninety-six of the isolates were methicillin-susceptible isolates from cultures of blood from consecutive patients. Also, 267 methicillin-resistant isolates that comprised 248 different phage types were tested. Methicillin resistance was defined as the presence of the mecA gene. Of the 267 mecA gene-positive isolates, 263 were positive by the MRSA screen test (sensitivity, 98.5%), and all the mecA-gene negative strains were negative by the MRSA screen test (specificity, 100%). The oxacillin agar screen test detected methicillin resistance in 250 of the mecA gene-positive isolates (sensitivity, 93.6%). The sensitivity of the MRSA screen test was statistically significantly higher than the sensitivity of the oxacillin agar screen test (P < 0. 05). The MRSA screen test is a highly sensitive and specific test for the detection of methicillin resistance. Also, it offers results within half an hour and is easy to perform, which makes this test a valuable tool in the ongoing battle against methicillin-resistant S. aureus.     

Sensitisation of TRPV1 in rat sensory neurones by activation of SNSRs

The novel sensory neurone specific receptor (SNSR) family of G-protein coupled receptors are activated by non-opiate fragments of opioid precursor peptides. SNSRs are expressed in nociceptors, and SNSR agonists have been found to cause sensitisation to painful stimuli in vivo. We explored the basis of sensitisation caused by SNSR agonists in sensory neurones by investigating the effect of the SNSR-selective agonist bovine adrenal medulla peptide 8-22 (BAM (8-22)) on gating of the heat and capsaicin-sensitive ion channel TRPV1. Using calcium imaging we found that BAM (8-22) caused sensitisation of the TRPV1 response in approximately 13% of DRG neurones. Sensitisation of TRPV1 in a similar proportion of neurones was observed using whole-cell patch clamping. The PKC-specific inhibitor Ro-31-8220 reduced but did not completely abolish sensitisation, while the protein kinase A inhibitor H-89 was without significant effect. No translocation of the PKC delta, epsilon and zeta isoforms to the cell membrane was observed in response to BAM (8-22). These observations implicate PKC in the sensitisation of TRPV1, but suggest that other pathways are also involved.     

Evaluation of the Wellcolex Agglutination Test for group identification of Salmonellae and Shigellae]

Color agglutination test Wellcolex for rapid group identification of Salmonella and Shigella species was evaluated. The test revealed high specificity and gave information on presence of Salmonella and Shigella species in biological material in 24 hours. The test is suitable for standard diagnostic laboratories.     

Coagglutination and counter immunoelectrophoresis in the rapid diagnosis of typhoid fever

The efficacy of two methods--coagglutination (COAG) and counter immunoelectrophoresis (CIE)--in the rapid diagnosis of typhoid fever was studied in parallel with blood and clot cultures on 114 clinically suspected cases. Retrospective analysis showed that only 58 eventually were discharged and had typhoid fever. Antigen detection on their sera was done by both methods, concomitant with antigen detection on culture supernates by CIE. Sera from 50 controls were subjected to both tests. Agglutinating anti-serum being unsatisfactory in the CIE system, anti-serum to the LPS fraction of Salmonella typhi "O" 901 was used in both tests after absorption with Escherichia coli and Salmonella paratyphi A. Analysis of data with reference to retrospectively confirmed typhoid cases show that S. typhi was isolated in 58.6% and 58.3% of blood and clot cultures; antigen detection by CIE in their supernates was 81.1% and 79.2%, respectively. This correlated closely with serum COAG (81.0%) in contrast to serum CIE (5.7%). Thus, COAG was superior to CIE for serology. However, CIE done on culture supernates precludes such tedious procedures as absorption of staphylococcal agglutinins and the confirmatory blocking test.     

A Modified Agglutination Test for Neospora caninum: Development, Optimization, and Comparison to the Indirect Fluorescent-Antibody Test and Enzyme-Linked Immunosorbent Assay

Current serologic tests used to detect antibodies to Neospora caninum require species-specific secondary antibodies, limiting the number of species that can be tested. In order to examine a wide variety of animal species that may be infected with N. caninum, a modified direct agglutination test (N-MAT) similar to the Toxoplasma gondii modified direct agglutination test (T-MAT) was developed. This test measures the direct agglutination of parasites by N. caninum-specific antibodies in serum, thus eliminating the need for secondary host-specific anti-isotype sera. The N-MAT was compared to the indirect fluorescent-antibody test (IFAT) and the enzyme-linked immunosorbent assay (ELISA) with a “gold standard” serum panel from species for which secondary antibodies were available (n = 547). All positive samples tested were from animals with histologically confirmed infections. Up to 16 different species were tested. The N-MAT gave a higher sensitivity (100%) and specificity (97%) than the ELISA (74 and 94%, respectively) and had a higher sensitivity but a lower specificity than the IFAT (98 and 99%, respectively). The reduced specificity of the N-MAT was due to false-positive reactions in testing fetal fluids with particulate matter or severely hemolyzed serum. Overall, the N-MAT proved to be highly sensitive and specific for both naturally and experimentally infected animals, highly reproducible between and within readers, easy to use on large sample sizes without requiring special equipment, and useful in testing serum from any species without modification.     

Continuous objective recording of fetal heart rate and fetal movements could reliably identify fetal compromise,which could reduce stillbirth rates by facilitating timely management

Stillbirth currently affects approximately 1 in every 200 pregnancies in the United Kingdom. Fetuses may exhibit signs of compromise as part of a stress response before stillbirth, including reduced fetal movements (RFM) and fetal heart rate (FHR) alterations. At present, and despite widespread use, current fetal monitoring is not associated with a reduction in perinatal mortality rate (PMR) as signs of fetal compromise are not adequately detected. This may be attributed to inaccuracies resulting from manual interpretation of results or subjective assessment of fetal activity. In addition, signs of compromise often occur only hours or days before fetal death, so may be missed by current monitoring methods, which are performed intermittently. A significant consideration is that correct identification of these signs and consequent intervention can result in the delivery of a healthy baby, thus preventing stillbirth. A hypothesis is presented, proposing prompt detection of fetal compromise with the use of 24-hour continuous objective fetal monitoring. With focus placed on obtaining long-term FHR and fetal movement data, prior interest has been found in developing devices for this purpose. However, introduction into clinical practice has not been achieved. Investigation of the hypothesis will begin with the design of a device to record the mentioned parameters, followed by an appropriate validation process. Should development and testing be successful, an eventual comparison in PMR with the use of continuous fetal monitoring vs current monitoring would address the hypothesis. It is suggested that a timely yet reliable indication of fetal wellbeing obtained via long-term monitoring would allow prompt and appropriate obstetric intervention and consequently reduce PMR.     

Sensitisation of articular afferents in normal and inflamed knee joints by substance P in the rat

To examine whether substance P (SP) influences the response properties of fine articular afferents in normal and acutely inflamed joints, single units were recorded from the rat knee during normal and noxious joint rotations. Only three of 39 units were activated by a single bolus injection of 0.1 mM SP. However, 35% (7/20) of the nerve fibres from the normal joint and 21% (4/19) of the units from the inflamed joint significantly increased their responses to movements after the SP injection. This was most prominent during noxious movements in normal joints, whereas in inflamed joints increase of responses occurred mainly during normal movements. These data indicate that SP may also be involved in the process of sensitisation of primary afferents during an inflammation.     

Agglutination of platelets by a serum factor in the presence of EDTA

The platelets of a patient with reticulum-cell sarcoma were found to exhibit agglutination and cytopathic changes when her blood was treated with EDTA but not with other anticoagulants. Investigation showed that the phenomenon was caused by a serum factor that was probably an antibody.