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Characterisation of epitopes of type 1 fimbriae of Salmonella using monoclonal antibodies specific for SEF21 fimbriae of Salmonella enteritidis.

Monoclonal antibodies (mAbs) were used to identify and characterise epitopes of type 1 (SEF21) fimbriae of Salmonella enteritidis. The distribution of the epitopes among salmonellas and other enterobacteria was investigated, as well as the influence of growth media and temperatures on their expression. At least four different epitope clusters were identified on SEF21 fimbriae of S. enteritidis. Two of these clusters were associated with fimbrial haemagglutinins that were either common to all salmonellae tested, or restricted only to S. enteritidis and S. dublin. The four epitope clusters were identified on type 1 fimbriae of most Salmonella serotypes, as well as non-haemagglutinating type 2 fimbriae of S. pullorum and S. gallinarum, and on many other enterobacterial species. The expression of the epitopes was affected by growth conditions.

Animals↗

Rapid immunodiagnosis of streptococci and enterococci in blood cultures.

We evaluated a procedure for rapid identification of blood culture isolates of pneumococci, enterococci and beta-haemolytic streptococci groups A, B, C, and G. Immunological tests were applied directly to blood culture medium and included a quellung reaction for pneumococci, and latex agglutination tests (LAT) for pneumococcal antigen and Lancefield antigens A, B, C, D and G. During a one-year trial period with approximately 12,000 blood culture sets (BacT/Alert, Organon-Teknika), 208 sets showed pure growth of gram-positive cocci in pairs or chains by direct microscopy. Overall, a correct diagnosis was noted for 103 (63.2%, 95% CI: 55.3-70.6%) of 163 sets yielding pneumococci, beta-haemolytic streptococci, or enterococci. A procedure excluding Lancefield antigens only A, B, and D was implemented during a one-year follow-up period. With this simplified procedure positive and negative predictive values, respectively, were 1.00 and 0.87 for pneumococci, 1.00 and 0.94 for beta-haemolytic streptococci group A, 0.60 and 1.00 for beta-haemolytic streptococci group B, and 0.91 and 0.88 for enterococci. We conclude that rapid identification of gram-positive cocci is feasible and may improve the information given to clinicians at the first notification of positive blood cultures.

Bacteremia↗

Granuloma annulare, nodular type--a subcutaneous pseudorheumatoid lesion in children.

Five cases of patients aged between 2 years 8 months and 5 years 6 months with subcutaneous nodular granuloma annulare are reported. Histologically the lesions resembled rheumatoid nodules, consisting of acellular central areas surrounded by palisading histiocytes. Complete or partial excisions were done for diagnosis. Initially the granulomata were not associated with any symptoms of systemic illness, but one patient with IgG deficiency developed subsequent polyarthritis. Antistreptolysin O, antinuclear antibodies and latex fixation test for rheumatoid arthritis were negative except for one patient with additional erythema nodosum and elevated antistreptolysin level. In the other patients the laboratory data were uncharacteristic. The clinical course may be characterized by spontaneous regression and frequent recurrence. In asymptomatic patients further treatment is not necessary. Patients with progressive disease or elevated inflammatory activity were treated with nonsteroidal antirheumatics. The development of subsequent rheumatoid disease in primarily asymptomatic patients is unlikely, but we recommend further observation by an experienced pediatrician.

Child, Preschool↗

Better diagnosis and treatment of throat infections caused by group A beta-haemolytic streptococci.

This study aims to assess the diagnostic value of a rapid streptococcal antigen test in addition to four clinical features in patients with sore throat, using throat culture and antibody titre as reference tests, and to evaluate the efficacy of the current antibiotics used in the treatment of throat infections caused by group A beta-haemolytic streptococcus (GABHS). Four clinical features (fever [history of] > or = 38 degrees C, lack of cough, tonsillar exudate, and anterior cervical lymphadenopathy) are recorded in 355 patients aged four years to > or =15 years. A rapid antigen diagnostic test (RADT) is performed, as well as a throat culture. Antistreptolysin O (ASO) titre is performed in patients 11 years. GABHS from patients are tested for susceptibility to different antibiotics. Throat cultures were positive for GABHS in 19% patients. Rapid tests were positive in 24%. Compared with throat culture, the rapid test gave a sensitivity of 91%, specificity of 91%, positive predictive value of 73% and a negative predictive value of 98%. For patients with three or four clinical features, however, the sensitivity was considerably higher at 97%. Using the ASO test as a reference, no association was found between RADT and culture results. Zithromax showed the highest prescription rate (25.5%) and produced a high cure rate (91%) in patients with GABHS pharyngitis.

Adolescent↗

Group identification of streptococci. Evaluation of three rapid agglutination methods.

The clinical need to rapidly and correctly differentiate beta-hemolytic streptococci into Lancefield groups has prompted the commercialization of rapid agglutination methods. Three serogrouping kits, Phadebact, Sero STAT, and Streptex, were compared with the classic precipitin technic. One hundred and fifty beta-hemolytic streptococci and 75 alpha-hemolytic streptococci isolated from clinical specimens were used. Phadebact grouped all beta-hemolytic strains correctly while Sero STAT and Streptex were 96.7% and 99.3% accurate, respectively. Phadebact and Streptex correctly identified all group D streptococci. Commercial agglutination reagents represent a simple and reliable method for grouping streptococci.

Agglutination Tests↗

Stimulation of Immunoglobulin production from human B lymphocytes by Staphylococcus aureus: effects of monocytes and con A-induced suppressor cells.

Significant immunoglobulin (Ig) production by human peripheral blood lymphocytes was induced in vitro by stimulating the cells with pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I (SpA CoI). IgG, IgM, and IgA were determined by a combination of the latex fixation test and radioimmunoassay. High levels (1,000 to 5,000 microgram/ml of IgG and IgM and a lesser amount of IgA were constantly produced during 7 to 8 days of incubation with both stimulants. Ig production induced by SpA CoI stimulation was independent of the presence of T cells, while Ig production induced by PWM required T cells exclusively. Depletion of monocytes in the culture caused but a slight decrease in Ig production (particularly in the case of IgG). While the addition of a small number of monocytes enhanced IgG induction by both stimulants, coculture with an excess number of monocytes inhibited Ig induction (particularly IgG) by PWM stimulation but not by SpA CoI stimulation. Marked suppression of Ig production (IgG, IgM, and IgA) was observed in cocultures with Con A-activated T cells. The phenomena of suppression were observed in both the SpA CoI-stimulated and PWM-stimulated lymphocytes. These data indicated that Ig production from B cells and relatively of independent of monocytes, but could be subjected to the regulation of the Con A-induced suppressor T cells.

Antibody Formation↗

Field validity, reproducibility and feasibility of diagnostic tests for visceral leishmaniasis in rural Nepal.

OBJECTIVES: To assess the field accuracy, reproducibility and feasibility of the formol gel test (FGT), the urine latex agglutination test (KAtex) and a rK39 antigen-based dipstick for the diagnosis of visceral leishmaniasis (VL) in rural Nepal. METHOD: Patients with clinical suspicion of VL were recruited at Rangeli District Hospital (DH), a 15-bed government hospital located in south-eastern Nepal. FGT, KAtex and rK39 dipstick tests were performed on site and later repeated at a reference kala-azar diagnostic laboratory to assess reproducibility. Diagnosis of VL was confirmed by either a positive bone marrow aspirate examination or a positive direct agglutination test (DAT titre > or = 1:3200) in patients who later responded to anti-leishmanial therapy. RESULTS: Of 155 patients initially recruited, 142 (85 with VL and 57 with another diagnosis) were included in the study. The sensitivity of the rK39 dipstick [89%; 95% confidence interval (CI): 81-94] was significantly higher than that of the KAtex (57%; 95% CI: 46-67) and the FGT (52%; 95% CI: 41-62). All three tests had a specificity of at least 90%. Agreement was higher for the rK39 dipstick (kappa = 0.87) than for the FGT (0.68) and the KAtex (0.43). All tests required < or = 20 min of actual work and < or = 40 min to obtain the results. CONCLUSION: The rK39 dipstick was easy to do, more accurate and reproducible than other rapid diagnostic tests for VL in a DH of rural Nepal. It should be integrated into the field diagnostic algorithm of VL in this region and mechanisms to secure its availability should be found.

Adult↗

Comparison of four methods for differentiation of Staphylococcus aureus from other Micrococcaceae in the routine laboratory.

Four methods for the identification of Staphylococcus aureus (tube coagulase test, thermostable nuclease test, indirect agglutination of fibrinogen coated erythrocytes and a commercial latex kit: SeroSTAT Staphylococcus Test) have been compared. Clinical isolates (698) and 40 reference strains of Micrococcaceae were included in the study together with control organisms. The coagulase test gave no false positive results but 39/406 clinical isolates of S. aureus were negative at 2h and one half were only weakly positive. At 18 h, all but 2 of 406 isolates gave a positive reaction. The thermostable nuclease test was very specific; no clinical isolates of S. aureus gave negative results and no "coagulase-negative" clinical isolates gave a definite positive reaction. The indirect haemagglutination method was sometimes difficult to interpret and frequently gave negative or doubtful results for S. aureus. The SeroSTAT test was easy to use and interpret and was specific; the method is suitable for routine laboratory use, particularly when a rapid result is desirable.

Bacteriological Techniques↗

Latex agglutination test for canine parvovirus.

Canine parvovirus (CPV) was detected in faeces from dogs with diarrhoea by a specific slide agglutination test using latex particles coated with anti-CPV monoclonal antibody (LA-anti-CPV). The agglutination of LA-anti-CPV with CPV on a glass slide was evident macroscopically within 2 min. The sensitivity of the latex agglutination (LA) test was similar to that of the hemagglutination test. The LA test is available for the rapid diagnosis of CPV infection at an animal hospital.

Animals↗

Concurrent infection with Toxoplasma gondii and feline leukemia virus. Antibody response and oocyst production.

Four adult cats (two testing positive and two negative for feline leukemia virus FeLV) were fed Toxoplasma gondii tissue cysts collected from the brains of mice. Two control cats (1 FeLV+, 1 FeLV-) were not fed cysts. The cats infected with T. gondii shed thousands of oocysts but remained clinically and physically normal, with hemograms and clinical chemistry values essentially unchanged irrespective of their FeLV status. Infection with FeLV did not increase the duration of oocyst shedding. At necropsy no significant lesions were found. T. gondii antibodies were detected by three serologic tests in the cats fed tissue cysts. The time necessary for an antibody response to T. gondii was not altered by the FeLV infection. Indirect hemagglutination (IHA) was the least reliable of the serologic tests studied; it detected antibodies later in the infection, and titers were less than in the other tests. Latex agglutination (LA) detected antibodies a few days before IHA, but titers were less than in modified direct agglutination (MAT). MAT detected antibodies earliest in the infection and also measured antibodies in aqueous humor and cerebrospinal fluid.

Agglutination Tests↗

[Anti-toxoplasma antibody levels in the main-land raccoon dog, Nyctereutes procyonoides viverrinus, in southeastern Kanagawa prefecture].

Naturally-occurring toxoplasma infection has been observed for years in various kinds of wild animals. However, the infection situation has not been well characterized due to a lack of research. In present study, latex fixation tests were conducted for 109 main-land raccoon dogs (67 males and 42 females) all of which were kept in Kanazawa Zoo in Yokohama City, Kanagawa Prefecture between 1991-1994 to measure levels of toxoplasma antibodies. The test results indicated 20 positive samples out of the total 109, an 18.3% positive rate. This demonstrates that toxoplasma infection exists in the raccoon dog population in Kanagawa Prefecture, and that the raccoon dog could be a source of spread of toxoplasma infection. We believe there is significant reason to continue the investigation as a part of a prophylaxis for zoonotic diseases.

Animals↗

Properties of Mycoplasma hominis 4330.

Mycoplasma strain 4330, one of the earliest strains of pleuropneumonia-like organisms to be isolated from man in the United States, has been found to resemble M. hominis type 1 by serological methods (the growth inhibition and latex agglutination tests). The results of earlier serological studies indicated a similarity between the Campo and 4330 strains which was not detected by use of the cultures currently available. Strain 4330 differs from strains of Mycoplasma recently isolated from man by producing acid from a variety of carbohydrates. This acquisition of biochemical properties may be the result of hundreds of transfers on artificial media during a period of more than a quarter of a century. Identification of the strain was deemed advisable, since two different cultures and a mixed culture existed under the designation "4330." The extraneous organisms were found to be closely related to M. laidlawii by their biological and serological properties.

Fermentation↗

Evaluation of various rapid agglutination methods for the identification of Staphylococcus aureus.

A latex agglutination test (SeroSTAT Staph; Scott Laboratories, Fiskeville, R.I.) and two hemagglutination tests (Staphyloslide; BBL Microbiology Systems, Cockeysville, Md.; and Hemastaph; Remel, Lenexa, Kans.) were compared with the slide coagulase (SC) and tube coagulase (TC) tests at room temperature (22 to 25 degrees C) and at 37 degrees C for the rapid identification of Staphylococcus aureus. A total of 380 clinical strains of staphylococci were tested. The TC test performed at room temperature yielded the largest number of TC-positive results (n = 239), and based on this observation 239 organisms were classified as S. aureus and 141 were classified as non-S. aureus. The SC, TC (37 degrees C), SeroSTAT Staph, Staphyloslide, and Hemastaph tests correctly identified 210 (87.9%), 221 (92.5%), 238 (99.6%), 239 (100%), and 236 (98.7%) of the S. aureus isolates, respectively. Of the S. aureus isolates that were TC positive at room temperature 68% required 24 h of incubation before coagulase production was detected. There was one false-negative SeroSTAT Staph result and one false-negative Hemastaph result. The Staphyloslide test yielded two noninterpretable results (both organisms were later confirmed as non-S. aureus), whereas there were six noninterpretable results recorded with the Hemastaph test (four organisms were classified as non-S. aureus, and two were classified as S. aureus). The SeroSTAT Staph, Staphyloslide, and Hemastaph tests were all more sensitive than the conventional SC and TC (37 degrees C) tests and were considerably more rapid than the TC test at either temperature.

Coagulase↗

Latex agglutination test for detecting feline panleukopenia virus, canine parvovirus, and parvoviruses of fur animals.

A latex agglutination (LA) test for the detection of parvoviruses of fur animals, cats, and dogs was developed, and its sensitivity and specificity were compared with those of hemagglutination (HA) and the enzyme-linked immunosorbent assay (ELISA). Tissue culture isolation was used to confirm the specificity results. Fecal samples from various sources were tested, including specimens from raccoon dogs and mink which were experimentally infected with parvoviruses by oral exposure. LA compared favorably with the other tests. The ELISA was the most sensitive. When it was considered as a reference test, the corresponding sensitivities for HA and LA were 96 and 91%, respectively. The specificities were 93% for the ELISA, 95% for the HA test, and 92% for the LA test. LA seems to be a suitable technique for screening animals in the field and in laboratories in which sophisticated techniques are not available.

Animals↗