RESUMO
An epitope-blocking enzyme-linked immunosorbent assay (b-ELISA) was evaluated for the diagnosis of West Nile virus (WNV) infections in humans. Sera from patients diagnosed with WNV infections from an outbreak in 2003 in Colorado and from patients diagnosed with dengue virus infections from Mexico and Thailand were tested with the b-ELISA. The b-ELISAs were performed using the WNV-specific monoclonal antibody (MAb) 3.1112G and the flavivirus-specific MAb 6B6C-1. Although the WNV-specific b-ELISA was effective in diagnosing WNV infections in humans from Colorado, it was not efficacious for diagnosing WNV infections in serum specimens from Mexico and Thailand. In serum specimens from patients from Colorado, the WNV b-ELISA and the WNV plaque reduction neutralization test showed an overall agreement of 91%. The sensitivity and specificity of the WNV b-ELISA were 89% and 92%, respectively, with a false-positive rate of 5%, based on receiver operating characteristic analysis. In contrast, false-positive rate results in specimens from the countries of Mexico and Thailand, where flaviviruses are endemic, were 79% and 80%, presumably due to the presence of antibodies resulting from previous dengue virus infections in Mexico and/or Japanese encephalitis virus infections or vaccination in Thailand. Thus, in regions where people have experienced previous or multiple flavivirus infections, the use of the b-ELISA for WNV diagnosis is contraindicated.
Assuntos
Febre do Nilo Ocidental/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais , Criança , Pré-Escolar , Ensaio de Imunoadsorção Enzimática , Reações Falso-Positivas , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Sensibilidade e Especificidade , Ensaio de Placa Viral , Adulto JovemRESUMO
A mutant of Bacillus subtilis ATCC 6051 deficient in phosphatidylethanolamine, an important membrane lipid, was isolated by a combination of nitrosoguanidine mutagenesis and penicillin concentration of auxotrophs employing phosphatidylethanolamine as a supplement. The mutant was compared to the parent strain with regard to lipid composition, growth, osmotic fragility, and staining character and differed substantially in each category. In addition to scant amounts of phosphatidylethanolamine, the mutant contained phosphatidylglycerol, cardiolipin, lysyl phosphatidylglycerol, and diglucosyldiglyceride, though in amounts differing from those found in the parent strain. The mutant was unable to grow appreciably on synthetic media, had enhanced osmotic fragility of protoplasts, and resisted decolorization in staining.
Assuntos
Bacillus subtilis/isolamento & purificação , Mutação , Fosfatidiletanolaminas/biossíntese , Bacillus subtilis/análise , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Isótopos de Carbono , Cromatografia DEAE-Celulose , Cromatografia em Papel , Meios de Cultura , Genética Microbiana , Glucose/metabolismo , Glicerídeos/análise , Lipídeos/análise , Mutagênicos , Nitrosoguanidinas , Fragilidade Osmótica , Penicilinas , Fosfatidiletanolaminas/análise , Fosfolipídeos/análise , Protoplastos , EspectrofotometriaRESUMO
A mutant of Bacillus subtilis ATCC 6051, demonstrated to be deficient in phosphatidylethanolamine, was found to differ from the parent strain in the rate of uptake of a variety of metabolites.
Assuntos
Bacillus subtilis/metabolismo , Transporte Biológico Ativo , Mutação , Fosfatidiletanolaminas/biossíntese , Acetatos/metabolismo , Adenosina/metabolismo , Aminoácidos/metabolismo , Ácido Aspártico/metabolismo , Bacillus subtilis/crescimento & desenvolvimento , Isótopos de Carbono , Membrana Celular/metabolismo , Meios de Cultura , Genética Microbiana , Glucose/metabolismo , Lisina/metabolismo , Piruvatos/metabolismo , Estereoisomerismo , Timina/metabolismo , Fatores de Tempo , Uracila/metabolismo , Uridina/metabolismoRESUMO
A gonococcal antibody test was introduced for use by the physician-clients of a private reference laboratory accompanied by distribution of literature regarding recommended use and interpretation of the test. The pattern of use of the tests was analyzed, and a telephone survey of clients was conducted to determine the manner of physician utilization of the test with regard to 69 patients with reactive test results. Despite recommendations to the contrary, the group surveyed used the test for males (22%) and symptomatic individuals (61%). Culture for Neisseria gonorrhoeae was not performed for 54% of patients with reactive tests for antibody to N. gonorrhoeae. Most physicians interviewed did not heed recommendations for the use of the test or correctly interpret test results.
Assuntos
Anticorpos Antibacterianos/isolamento & purificação , Gonorreia/diagnóstico , Testes de Fixação do Látex/estatística & dados numéricos , Neisseria gonorrhoeae/imunologia , Feminino , Humanos , Neisseria gonorrhoeae/isolamento & purificaçãoRESUMO
Five commercial enzyme-linked immunoassay systems for the detection of human immunodeficiency virus type 1 antibody from filter paper disks impregnated with whole blood were evaluated for technical and operational performance. All five systems performed adequately in the technical challenges posed, with specificities in excess of 99% for 1,020 specimens. In a serial dilution sensitivity challenge, all of the kits were able to detect specific antibody within one dilution of a Western blot (immunoblot) standard, except for a Du Pont Co. kit, which detected antibody within two dilutions of the standard. The Du Pont assay showed the least variation in control values between test runs and between lots. All of the systems produced acceptable results, but their operational parameters differed significantly.
Assuntos
Ensaio de Imunoadsorção Enzimática , Anticorpos Anti-HIV/análise , HIV-1/imunologia , Filtração , HumanosRESUMO
Table 6 is a summary of the organisms discussed with a listing of the environmental source, the endogenous source, the predisposing factors including neoplasms, and the postulated mechanisms by which the organism can gain access to the circulation. The evidence considered indicates that the entrance of one of these microorganisms into the bloodstream of a human being depends on the presence of multiplicity of predisposing factors. In the majority of cases of bacteremia due to one of these unusual organisms, two or more predisposing factors are present. Certain predisposing factors, such as cancer chemotherapy or intravenous catheterization, often provide a barrier break, while others, such as liver disease, may render the host immune system less capable of clearing organisms from the circulation. For organisms such as Campy-lobacter, Listeria, and Salmonella spp., attributes that allow the invasion of a healthy host are present and seem to be enhanced by the simultaneous presence of a predisposing condition, such as liver disease, in the host. Although somewhat fragmentary, a number of individual case reports describe bacteremia due to one of these organisms occurring weeks to years after surgery and after other therapeutic measures had effected a supposed cure of a cancer. It may be speculated that cancer patients, even after a cure, are still susceptible to bloodstream invasion by one of the aforementioned organisms by virtue of the presence of one or more predisposing metabolic, physiologic, or immunologic factors, even though these factors may be cryptic. The predominance of hematologic malignancies among cases of bacteremia due to these unusual organisms is also apparent. Although, as pointed out by Keusch (169), the reduction in the performance of immune function in hematologic malignancies compared with solid tumors is likely to be responsible, other associations of certain organisms with specific neoplasms warrant further examination. The frequency of bloodstream infections of Salmonella typhimurium and Capno-cytophaga canimorsus in Hodgkin's disease patients seems likely due to a particular mechanism which infection by these species is favored. The specific nature of these mechanisms remains to be determined. The recovery of any unusual bacterium from blood should warrant a careful consideration of the possibility of underlying disease, especially cancer. Microbiologists should advise clinicians of the unusual nature of the identified organism and provide the counsel that certain neoplastic processes, often accompanied by neutropenia, render the human host susceptible to invasion by almost any bacterium. The recovery of such organisms as C. septicum or S. bovis should prompt the clinician to aggressively seek to identify an occult neoplasm if one has not yet been diagnosed.
Assuntos
Bacteriemia/microbiologia , Bactérias Gram-Positivas/isolamento & purificação , Neoplasias/microbiologia , Bacteriemia/complicações , Bacteriemia/etiologia , Humanos , Neoplasias/complicaçõesRESUMO
Three strains of Branhamella catarrhalis and three strains of Neisseria gonorrhoeae were analyzed with regard to their phospholipid and neutral lipid composition. B. catarrhalis (ATCC 23246) contained 5.12 +/- 0.34% lipid, determined gravimetrically, compared to 8.56 +/- 0.15% and 9.73 +/- 0.06% for two strains of N. gonorrhoeae. Cardiolipin, phosphatidylglycerol, and phosphatidyl-ethanolamine were identified in extracts of both species. In addition, B. catarrhalis contained small amounts of phosphatidylcholine, and N. gonorrhoeae contained small amounts of lyso-phosphatidylethanolamine, which accumulated with autolysis accompanying late cell culture growth. The kinetics of change of relative amounts of phospholipids in both species were measured and found to differ substantially. Neutral lipid accounted for 30.4% of the total lipid of B. catarrhalis (ATCC 23246) and 7.6% of the total lipid of N. gonorrhoeae NYH 002. Hydrocarbons, triglycerides, free fatty acids, coenzyme Q, diglycerides, and free hydroxy fatty acids were identified in the neutral lipid fraction of both species. The three strains of N. gonorrhoeae, sensitive, intermediate, and resistant to penicillin, exhibited no significant difference in the composition or metabolism of phospholipid.
Assuntos
Lipídeos/análise , Neisseria gonorrhoeae/análise , Neisseriaceae/análise , Antibacterianos/farmacologia , Cardiolipinas/análise , Diglicerídeos/análise , Resistência Microbiana a Medicamentos , Ácidos Graxos não Esterificados/análise , Hidrocarbonetos/análise , Neisseria gonorrhoeae/efeitos dos fármacos , Fosfatidilcolinas/análise , Fosfatidiletanolaminas/análise , Fosfatidilgliceróis/análise , Fosfolipídeos/análise , Especificidade da Espécie , Triglicerídeos/análise , Ubiquinona/análiseRESUMO
The extracellular lipid of Thiobacillus thiooxidans is a heterogeneous mixture of phospholipid and neutral lipid, primarily free fatty acids.
Assuntos
Lipídeos/análise , Thiobacillus/análise , Clorofórmio , Cromatografia em Papel , Cromatografia em Camada Fina , Densitometria , Ácidos Graxos não Esterificados/análise , Glicerídeos/análise , Hidrocarbonetos/análise , Lipídeos/isolamento & purificação , Metanol , Fosfatidiletanolaminas/análise , Fosfatidilinositóis/análise , Fosfolipídeos/análiseRESUMO
We describe a comparative evaluation of commercial fluorescent treponemal antibody-absorbed test kits, using 150 selected patient sera. The ability of the test kits to detect reactive sera varied from 82.5 to 95%; that for nonreactive sera varied from 80.9 to 96.4%. Reproducibility of reactive and nonreactive results, measured by between-assay and within-assay studies, averaged 42%. The results showed substantial variation in performance characteristics among the kits, with important clinical implications for the diagnosis of syphilis. We recommend the development of an immunological standard for use in the manufacture of fluorescent treponemal antibody-absorbed test kits, with the goal of obtaining uniform performance characteristics among commercial test kits.
Assuntos
Anticorpos Antibacterianos/análise , Kit de Reagentes para Diagnóstico/normas , Sorodiagnóstico da Sífilis/normas , Treponema pallidum/imunologia , Estudos de Avaliação como Assunto , Imunofluorescência , HumanosRESUMO
BACKGROUND AND OBJECTIVES: Confirmation testing using nucleic acid amplification has been shown to improve the sensitivity and specificity of screening tests for Chlamydia trachomatis. However, no critical information on the use of these techniques as an adjunct to Gen-Probe hybridization testing, one of the most common screening methods, has been reported to date. We examined the Roche AMPLICOR PCR C. trachomatis Test (Roche Diagnostic Systems, Branchburg, NJ) as a confirmatory test for the Gen-Probe PACE 2 C. trachomatis Test (San Diego, CA). Further, to mitigate the possible effect of interfering compounds in the Gen-Probe PACE 2 transport medium, we tested various DNA purification techniques. STUDY DESIGN: C. trachomatis elementary bodies were used to spike PACE 2 Transport medium, which was serially diluted, then tested by polymerase chain reaction (PCR). Six parallel dilution series were conducted: (1) saline dilutions tested by the Syva Direct Specimen Test, (2) Roche AMPLICOR transport medium dilutions tested by PCR, and (3-6) dilutions in PACE 2 transport medium purified respectively by GENECLEAN II (BIO101, Vista, CA), Puregene (Gentra Systems, Inc., Research Triangle Park, NC), Microcon 100 (Amicon, Inc., Beverly, MA) DNA isolation kits, and no DNA purification, all tested by PCR. The system giving the best results by in vitro endpoint dilution trials was then used to confirm human specimens previously tested by the Gen-Probe method. RESULTS: PCR detected C. trachomatis at 11 twofold dilutions greater than PACE 2 and equivalent to detection of single elementary body by Syva Direct Specimen Test. DNA purification of spiked PACE 2 transport medium by the Microcon 100 kit produced the most consistent PCR detection endpoints, equivalent to endpoints of spiked AMPLICOR transport medium. Endpoints with no DNA purification step were variable and lower. Of 78 endocervical specimens negative by PACE 2 and Gen-Probe Probe Competition Assay, 12 (15.3%) were positive by Microcon DNA purification/PCR testing. CONCLUSIONS: PCR can be used as confirmation method for Gen-Probe PACE 2 testing, but testing must be performed with a DNA purification procedure.
Assuntos
Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis/genética , DNA Bacteriano/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Kit de Reagentes para Diagnóstico , Feminino , HumanosRESUMO
The multiplication rate of bacteria in undiluted blood containing sodium polyanethol sulfonate was compared with growth rates obtained in dilutions of blood ranging from 1:2 to 1:8. Although all organisms tested grew in the undiluted blood, increased growth rates were seen in the 1:2 dilution. Further dilution resulted in growth rates equivalent to that obtained with the 1:2 dilution. In view of these results, we question the present recommendations that blood be diluted 1:10 or 1:20.
Assuntos
Bactérias/isolamento & purificação , Sangue/microbiologia , Meios de Cultura , Bactérias/crescimento & desenvolvimento , Bacteroides fragilis/crescimento & desenvolvimento , Divisão Celular , Escherichia coli/crescimento & desenvolvimento , Humanos , Polianetolsulfonato , Pseudomonas aeruginosa/crescimento & desenvolvimento , Especificidade da Espécie , Staphylococcus aureus/crescimento & desenvolvimento , Streptococcus/crescimento & desenvolvimentoRESUMO
Penicillin-resistant and -susceptible strains of Neisseria gonorrhoeae were evaluated for the presence of enzymes capable of degrading penicillin by incubation of [(14)C]benzylpenicillin with resting-cell suspensions of N. gonorrhoeae followed by extraction and chromatography of the labeled antibiotic. No degradative activity was observed.
Assuntos
Neisseria gonorrhoeae/enzimologia , Resistência às Penicilinas , Penicilinase/metabolismo , Penicilinas/farmacologia , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/metabolismo , Penicilina G/metabolismoRESUMO
A series of gray zone specimens with sample to cutoff ratio of 0.7 to 0.99 encountered in routine use of the Syva Microtrak (Syva, Inc.) Chlamydia trachomatis enzyme immunoassay (EIA) test for urogenital specimens were subjected to repeat testing in duplicate and high-speed centrifugation with direct fluorescent antibody testing of the centrifugate. Immunofluorescent C. trachomatis elementary bodies were observed in high-speed centrifugates in more than 40% of two series of gray zone specimens examined indicating that a C. trachomatis gray zone result would require confirmatory testing.
Assuntos
Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis/isolamento & purificação , Colo do Útero/microbiologia , Feminino , Imunofluorescência , Humanos , Técnicas ImunoenzimáticasRESUMO
Twenty-one cases of bacteremia due to Bifidobacterium, Eubacterium and Lactobacillus are described. Transient bacteremic episodes with these organisms may follow trauma to the mouth, intestine, or vagina. The majority of the patients were female and most had an underlying condition that may have predisposed to bacteremia. Ten of the patients died despite antibiotic treatment.
Assuntos
Actinomycetaceae , Eubacterium , Lactobacillus , Sepse/etiologia , Actinomycetaceae/isolamento & purificação , Adulto , Idoso , Eubacterium/isolamento & purificação , Feminino , Humanos , Lactobacillus/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Gravidez , Complicações Infecciosas na Gravidez/etiologiaRESUMO
Women attending family planning clinics in Colorado during 1988 were screened for Chlamydia trachomatis infection by enzyme immunoassay (EIA, Chlamydiazyme, Abbott Laboratories; Abbott Park, IL). Cervical specimens from 11,793 women attending 22 family planning clinics were analyzed. Patient history and physical exams were used to assess risk factors for infection. A total of 913 individuals (7.7%) had positive culture results for C. trachomatis. Multivariate analysis showed that infection was significantly related to endocervical bleeding, cervical mucopurulent discharge, a new sexual partner in the last 3 months or multiple previous sexual partners (greater than 3) in the last year, pregnancy, the use of oral contraceptives, and age. Increased odd ratios were observed for the combination of endocervical bleeding and mucopurulent discharge and sexual history that included partners over the previous year as well as the most recent 3 months. A combination of these criteria was used to selectively screen women attending Colorado family planning clinics on an ongoing basis. A cost-benefit analysis employing a model reported previously showed a significant financial benefit associated with universal screening over either selective screening or no screening for C. trachomatis in this population.
Assuntos
Infecções por Chlamydia/prevenção & controle , Chlamydia trachomatis , Programas de Rastreamento/economia , Adolescente , Adulto , Idoso , Instituições de Assistência Ambulatorial , Criança , Infecções por Chlamydia/economia , Infecções por Chlamydia/epidemiologia , Colorado/epidemiologia , Análise Custo-Benefício , Serviços de Planejamento Familiar , Feminino , Humanos , Programas de Rastreamento/métodos , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
While there is substantial evidence of the importance of endogenous and exogenous estrogen in reproductive health and chronic disease, there is little consideration of androgens in women's health. In the Michigan Bone Health Study (1992-1995), the authors examined the correlates of testosterone concentrations in pre- and perimenopausal women (i.e., age, menopausal status, body composition, and lifestyle behaviors) in a population-based longitudinal study including three annual examinations among 611 women aged 25-50 years identified through a census in a midwestern community. Current smokers had the highest testosterone concentrations with decreasing values in former and nonsmokers (p = 0.0001). Body composition measures (body mass index, body fat (%), weight (kg), lean body mass (kg), and fat mass (kg)) were significantly and positively associated with total testosterone concentrations in a dose-response manner. Hysterectomy with oophorectomy was associated with significantly lower testosterone concentrations. Alcohol consumption, physical activity, and dietary macronutrient intake were not associated with testosterone concentrations. This is one of the first studies to examine correlates of serum testosterone concentrations in anticipation of the growing interest in the role of androgens in women's health. The greater circulating levels of testosterone in obese women and smokers suggest that testosterone concentrations should be considered in the natural history of disease conditions where obesity and smoking are risk factors, including cardiovascular disease.
Assuntos
Consumo de Bebidas Alcoólicas/sangue , Composição Corporal , Menopausa/sangue , Pré-Menopausa/sangue , Fumar/sangue , Testosterona/sangue , Adulto , Análise de Variância , Antropometria , Anticoncepcionais Orais/administração & dosagem , Terapia de Reposição de Estrogênios , Exercício Físico , Feminino , Humanos , Histerectomia , Estilo de Vida , Estudos Longitudinais , Pessoa de Meia-Idade , OvariectomiaRESUMO
BACKGROUND AND OBJECTIVES: The Syva Micro Trak enzyme immunoassay (EIA) is used widely for screening women infected with Chlamydia trachomatis. Confirmatory tests used in conjunction with EIA screening have shown that false-positive results are common. GOALS: To evaluate the specificity of the Syva MicroTrak EIA by confirmation of positive specimens with the Syva Direct Fluorescent Specimen Test. STUDY DESIGN: Of 6,039 endocervical specimens collected from women attending Colorado family planning clinics, 328 positive EIA results (5.4%) were obtained by Syva MicroTrak EIA. A random subset of 136 positive specimens was tested by Syva Direct Specimen Test. Twenty of 136 specimens (14.7%) negative by Syva Direct Specimen testing were also tested by Syva blocking antibody tests (9 of 20 positive, 45%) and Roche Amplicor polymerase chain reaction (PCR; 6 of 20 positive, 30%). Of 20 specimens positive by Syva MicroTrak EIA and negative by Syva Direct Specimen Test, 11 (55%) were also negative by blocking antibody and PCR, including three specimens with initial EIA sample-to-cutoff ratios greater than 2. CONCLUSIONS: Confirmatory testing of Syva MicroTrak EIA positive specimens with Syva Direct Specimen Test showed that 14.7% were false positive. Coupling the Syva Direct Specimen test with either blocking antibody or PCR reduces the rate of false-positive results to 8%.
Assuntos
Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis/isolamento & purificação , Técnica Direta de Fluorescência para Anticorpo , Técnicas Imunoenzimáticas , Cervicite Uterina/microbiologia , Reações Falso-Positivas , Feminino , Humanos , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade , Cervicite Uterina/diagnósticoRESUMO
BACKGROUND: Endocervical specimen adequacy has been assessed by subjective criteria that are based on arbitrarily chosen thresholds for the presence of target cells observed on microscopic slide examinations. GOAL OF THIS STUDY: To assess the relationship of chlamydia test positivity to specimen adequacy with the use of a semi-quantitative cytologic staining method for assessing endocervical specimen collection cellularity. STUDY DESIGN: Endocervical specimens for chlamydia testing (PACE 2, GenProbe, San Diego, CA) and for a slide cytologic examination (n = 3,500) were collected in parallel. A semi-quantitative cytologic examination to determine a specimen adequacy (SA) score was performed for every chlamydia-positive result (n = 163) and approximately every fifth negative result (n = 626). The Chi-square test for linear trends was used to assess the relationship between SA scores and chlamydia positivity. The median SA scores for chlamydia-positive and negative slides were compared. RESULTS: The median SA scores for chlamydia-positive and -negative slides were 27 and 20, respectively (P < 0.001). Chlamydia positivity rates increased with increasing specimen adequacy scores (0-9, 2.7%; 10-19, 15.1%; 20-29, 24.8%; and 30-45, 31.3%; Chi-square for linear trend: P < 0.001). CONCLUSION: These results demonstrate a linear relationship between the numbers of cells observed on an endocervical smear and chlamydia positivity rather than the threshold concept in practice. The semiquantitative cytologic technique offers an objective method for further evaluating specimen adequacy for Chlamydia trachomatis testing.
Assuntos
Colo do Útero/microbiologia , Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis/isolamento & purificação , Manejo de Espécimes/normas , Feminino , Humanos , Esfregaço VaginalRESUMO
Over 18,000 clinical specimens collected in Vacutainer tubes with sodium polyanethol sulfonate were inoculated into modified Columbia broth (MCB) with and without 10% sucrose. The effects of venting and shaking on recovery were studied. The volume of the blood had a definite effect on the recovery rate. When inoculum size was held constant, recovery of aerobic and facultative organisms was maximal in vented and shaken bottles; the presence of sucrose had no demonstrable effect, recovery of anaerobes was maximal using an unvented bottle incubated under stationary conditions; a significantly greater recovery of facultatives and a marginally greater recovery of anaerobes was obtained with the hypertonic formulation. We conclude that a hypertonic formulation of MCB offers no advantage in the recovery of anaerobes but is of value in the recovery of facultatives and anaerobes. It is recommended that blood cultures be routinely inoculated into isotonic MCB and then vented and shaken for at least 4 hours, and hypertonic MCB incubated without venting or shaking.
Assuntos
Bactérias/isolamento & purificação , Meios de Cultura , Sepse/diagnóstico , Aerobiose , Anaerobiose , Diagnóstico Diferencial , Estudos de Avaliação como Assunto , Humanos , Soluções Hipertônicas , Especificidade da Espécie , SacaroseRESUMO
To determine the accuracy of the Syva (Palo Alto, Calif.) direct fluorescent-antibody (DFA) test in comparison with the Gen-Probe (San Diego, Calif.) Accuprobe culture confirmation test, we tested 395 isolates of Neisseria gonorrhoeae from cultures obtained from patients attending a sexually transmitted disease clinic from 1 July 1991 through 30 June 1992. All isolates were tested for DFA reactivity with a polyclonal reagent (Difco Laboratories, Detroit, Mich.) and a monoclonal reagent (Syva, Inc., direct specimen test) and for specific molecular probe reactivity by the Gen-Probe Accuprobe culture confirmation test for N. gonorrhoeae. The 395 isolates gave positive results for the Gen-Probe culture confirmation test and the Difco polyclonal direct specimen test. However, 18 (4.6%) of the isolates were negative for N. gonorrhoeae by the Syva DFA test. With the exception of six beta-lactamase-positive isolates, all isolates that were negative by Syva DFA were sensitive to penicillin, tetracycline, spectinomycin, and ceftriaxone by disk-diffusion susceptibility testing. Auxotyping and serotyping studies indicated that strains negative by Syva DFA consisted of several variants. The frequency of N. gonorrhoeae isolates showing negative results by Syva DFA in this patient population ranged from 0 to 11.5%/month. Laboratories using only the Syva DFA test for confirmation of N. gonorrhoeae may incur a significant risk of misidentification.