Método de aglutinación en látex para el diagnóstico rápido del síndrome de Guillain-Barré / Latex agglutination method for fast Guillain-Barré syndromes diagnosis

El síndrome de Guillain-Barré es una polirradiculoneuropatía aguda, en la cual está involucrado un componente autoinmunitario, posterior a un proceso infeccioso en pacientes no vacunados o vacunados. A partir de la aparición del virus del dengue y del Zika en el continente americano es de esperar que exista una mayor probabilidad de encontrar pacientes con este síndrome post-infeccioso. Por tanto, poder contar con un método diagnóstico rápido pudiera ser de utilidad en los centros de asistencia que reciben casos de urgencias. Se procede a modificar un método para cuantificar albuminuria por aglutinación con partículas de látex sensibilizados, para la detección de este analito en el líquido cefalorraquídeo de aquellos pacientes con sospecha de esta enfermedad. Se comprueba que el método puede ser utilizado como método de diagnóstico rápido del síndrome de Guillain-Barré(AU)

Guillain-Barré Syndrome is an acute poliradiculoneuropathy with an autoimmune component, subsequent to an infectious process in vaccinated or non-vaccinated patients. From the spreading of dengue and Zika infections in the American continent it is expected a greater probability of finding patients with this post-infectious syndrome. Therefore, a rapid diagnostic test could be useful in emergency assistance centers. A quantitative latex agglutination test to detect albuminuria was modified to be used in cerebrospinal fluid of patients with presumptive diagnosis of this disease. It has been proved that the developed test can be used for diagnostic rapid of Guillain-Barré syndrome(AU)

Development and assessment of a latex agglutination test based on recombinant MSP5 to detect antibodies against Anaplasma marginale in cattle

The recombinant protein MSP5 has been established as an important antigen for serological diagnosis of Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). However, due to the high cost of specialized equipment, this technique is not accessible to all laboratories, especially in developing countries in areas where the disease is endemic. The present study describes the standardization of a latex agglutination test (LAT) to detect antibodies against A. marginale based on recombinant MSP5. Compared with indirect enzyme-linked immunosorbent assay (iELISA), the relative sensitivity and specificity of the LAT were 95.21% and 91.86% respectively, with an almost perfect agreement between tests (kappa index = 0.863). These results can be considered important for the serological diagnosis of A. marginale, as they indicate that the test represents a rapid and low cost alternative to ELISA.

Development of a peptide based latex agglutination assay for serotype identification of foot and mouth disease virus.

Out of 200 serum samples collected from cattle (142) and buffaloes (58) of various ages and sexand subjected to latex agglutination test (LAT) using serotype specific peptides (O, A, Asia 1) and also with peptide for non-structural protein 2B (NSP-2B), 114 (70%) samples were positive against FMDV type ‘O’, 102 (51%) against serotype ‘A’ and 104 (52%) against serotype ‘Asia 1’. With NSP-2B peptide a total of 71 (35.5%) samples were positive. The results suggest that LAT could be used for the diagnosis of foot and mouth disease virus as it is easy, cheap and effective test.

Comparative study between immunoturbidimetric and latex agglutination methods for the detection of rheumatoid factor / Estudo comparativo entre as técnicas de aglutinação em látex e de imunoturbidimetria para a detecção de fator reumatoide

INTRODUCTION: The rheumatoid factor (RF) is the most common antibody found in patients with rheumatoid arthritis. It is an inflammatory chronic disease characterized by articular involvement, inflammation of synovial fluid, tissue infiltration by leucocytes and joint destruction, which ultimately determine articular deformities. The rheumatoid factor is found in 70%-80% of the adult population and in 10% of the young population. OBJECTIVE: The aim of this research was to compare immunoturbidimetric and latex agglutination methods for the detection of RF in serum. RESULTS: The immunoturbidimetric method displayed sensitivity (95.2%), specificity (89.4%) and high positive correlation (R² = 0,8077) with the latex agglutination method in positive serum samples. CONCLUSION: The study allowed to demonstrate that both immunoturbidimetric and latex agglutination methods equally discriminate between negative and positive serum samples for RF.

INTRODUÇÃO: O fator reumatoide (FR) é o autoanticorpo mais comum encontrado em pacientes com artrite reumatoide, uma doença crônica inflamatória caracterizada pelo envolvimento articular com inflamação do líquido sinovial, infiltração de tecido por leucócitos e destruição das articulações, que acaba por determinar deformidades articulares. O FR é encontrado em 70%-80% da população adulta e em 10% da população juvenil. OBJETIVO: Comparar os métodos de imunoturbidimetria e aglutinação (prova do látex) para a determinação de FR em soro. RESULTADO: Foi possível observar que o método imunoturbidimétrico apresenta sensibilidade (95,2%), especificidade (89,4%) e correlação positiva elevada (R² = 0,8077) com o método de aglutinação pelo látex em amostras de soro positivas. CONCLUSÃO: O estudo permitiu demonstrar que o método imunoturbidimétrico e o método de aglutinação pelo látex são igualmente capazes de discriminar amostras negativas e positivas para FR.

Evaluación de un método de aglutinación con partículas látex sensibilizadas para el diagnóstico de Gardnerella vaginalis / Evaluation of a sensitized latex particles-based agglutination method for Gardnerella vaginalis diagnosis

Introducción: la vaginosis bacteriana constituye una de las infecciones ginecológicas más prevalentes, asociada a afecciones obstétricas y ginecológicas como son: partos prematuros, bajo peso al nacer, rotura prematura de membranas ovulares, endometritis posparto, inflamación pélvica y riesgo de infertilidad, entre otras. Objetivo: incrementar la calidad del diagnóstico de vaginosis bacteriana. Métodos: se evaluó una técnica de aglutinación por látex para el diagnóstico de Gardnerella vaginalis, empleando un reactivo elaborado en la planta de Medios Diagnosticadores del Centro Nacional de Sanidad Agropecuaria (CENSA), a través del estudio de 500 muestras de exudados vaginales de mujeres que acudieron al Departamento de Microbiología del Hospital Docente Materno Infantil Diez de Octubre, durante los meses de febrero a julio de 2004. Resultados: la técnica evaluada mostró una sensibilidad de 98,05 por ciento y una especificidad de 89,02 por ciento, al compararla con 3 de los 4 criterios propuestos por Amsel y otros en 1983 para el diagnóstico de la vaginosis bacteriana, complementado con la técnica de coloración de Gram. El valor global de la prueba fue de 91,80 por ciento. Las pacientes cuyas edades oscilaron entre los 20 y 24 años mostraron la mayor incidencia a la infección con 28,04 por ciento de positividad al patógeno. Se diagnosticó la presencia de Gardnerella vaginalis mediante la técnica de látex en 37,8 por ciento de las muestras estudiadas. Conclusión: la técnica resultó rápida y sencilla; se pudo realizar en las propias consultas de ginecología por el personal paramédico y con ello establecer el tratamiento específico el mismo día.

Background: Bacterial vaginosis is one of the most prevailing gynaecological infections associated to obstetric and gynaecological problems such as preterm deliveries, low birhtweight, premature rupture of ovular membranes, postpartum endometritis, pelvic inflammation and risk of sterility, among others. Objective: to increase the quality of diagnosis of bacterial vaginosis. Methods: latex agglutination technique was evaluated for Gardnerella vaginalis diagnosis by using a reagent produced at the Diagnosing Media plant of the National Center of Agricultural Health(known as CENSA) and 500 vaginal smears from females who went for testing to the microbiology department of Diez de Octubre maternal and child hospital from February to July,2004. Results: the evaluated technique showed 98.05 percent sensitivity and 89.02 percent specificity rates when compared to three of the four Amsel et al´s criteria for bacterial diagnosis in 1983, supplemented by the Gram staining method. The overall value of this test was 91.80 percent. The patients aged 20-24 years showed the highest incidence rate of infection, with 28,04 percent positive samples to this pathogen. Gardnerella vaginalis was detected in 37.8 percent of the studied specimens through the latex technique. Conclusion: this technique was rapid and simple; it was performed at the gynaecological service offices by the paramedic staff, and thus, the specific treatment to be followed for this illness was quickly determined.

Bacterial meningitis: rapid diagnosis and microbial profile: a multicentered study.

Meningitis continues to be a formidable illness with high morbidity and mortality among children in India. The present study was undertaken to prospectively look for the prevalence of pyogenic meningitis at Gulbarga and to find out the utility of gram stain, Latex Agglutination Test and (LTA) and C-reactive protein in the rapid diagnosis of pyogenic meningitis from children. Over a 48-months period, 535 children with a presumptive clinical diagnosis of acute bacterial meningitis were investigated by direct microscopy, CRP, bacterial culture, latex agglutination test (L TA), cell count and cell type and biochemical tests. Latex Agglutination Test (LA T) was done for detection of the antigens of Streptococcus pneumoniae, Group B Streptococci, E. coli, Neisseria meningitidis and Haemophilus influenzae type b. Among 535 suspected meningitis cases, 291 cases were diagnosed as pyogenic meningitis cases based on biochemical tests, cell count and cell type. Out of 291 cases, 55 cases have already received antibiotic treatment. Among 236 cases of untreated pyogenic meningitis cases, 199 CSF samples were culture positive. Streptococcus pneumoniae (44.7%) was the predominant organism identified, followed by H influenzae (25.6%) and Gp. B. Streptococci (9.5%). 208 of 236 cases were gram-stain positive, 129 cases had elevated CSF-CRP and 214 cases were diagnosed as pyogenic meningitis by the detection of bacterial antigens by latex agglutination test. Among 55 pretreated cases, only 05 (9.1%) CSF samples were culture positive, bacteria was observed in 36 gram stain smear, CRP was elevated in 16 CSF samples and 52 pretreated cases of suspected meningitis were diagnosed as pyogenic meningitis by latex agglutination test for detection of bacterial antigens. Many of the bacterial isolates were sensitive to gentamicin, cefotaxime and ceftriaxone and least sensitive to tetracycline and gentamicin. 13.1% of gram-negative bacilli were ESBL producers. To conclude, inclusion of latex agglutination test for detection of bacterial antigen in the routine diagnosis adds a valuable adjunct in the rapid and accurate diagnosis of pyogenic meningitis.

Evaluación de un método de aglutinación con látex para la detección de factor reumatoide / Evaluation of a latex agglutination method for the detection of rheumatoid factor

Se evaluó un método de aglutinación con látex de producción nacional (Centis), para la detección de factor reumatoide, empleándose como procedimiento de referencia un ensayo turbidimétrico con látex (Spin React, España) en un grupo de pacientes con artritis reumatoide. Los resultados obtenidos en el método evaluado: sensibilidad 93 por ciento; especificidad 80 porciento; valor predictivo positivo 97,6 por ciento; valor predictivo negativo 57,1 por ciento; y un límite de detección de 15 UI/mL, indican su calidad y utilidad.

An agglutination method with latex of national production (Centis) was evaluated to detect the rheumatoid factor by using a turbidimetric assay with latex (Spin React, Spain) as a reference procedure in a group of patients with rheumatoid arthritis. The results obtained in the evaluated method (sensitivity 93 percent, specificity 80 percent, positive predictive value 97.6 percent, negative predictive value 57.1 percent, and a detection limit of 15 UI/mL) showed its quality and usefulness.

Antigen detection from urine of Kala-azar cases by latex agglutination tes.

A recently developed Latex agglutination method known as "KATEX" for detecting leishmanial antigen in urine of Kala-azar patients was evaluated on 97 Kala-azar cases and 35 controls in the department of Microbiology, Mymensingh Medical College during the period from March' 2004 to February' 2005. The method yielded sensitivity as 100% and 82.8% in 33 confirmed and 64 ICT positive cases respectively. Since 8.6% controls showed antigen positive results, so specificity of KATEX was calculated as 91.4%. KATEX methods for antigen detection in urine should be used as an early immuno-diagnostic test as it has yielded high sensitivity. But interpretation of a positive test must be made cautiously having correlation with clinical findings as because it becomes false positive in Kala-azar free person. Further elucidation of KATEX method including larger population from community giving particular emphasis on its prognostic use was strongly recommended.

Latex particle agglutination test as an adjunct to the diagnosis of bacterial meningitis.

The present study aimed to review the results of microscopic examination, routine culture and antigen detection by latex particle agglutination test (LPAT), in order to evaluate the diagnostic value of the LPAT in establishing the aetiological diagnosis of bacterial meningitis. LPAT was done in 65 clinically suspected meningitis cases ranging from 5 days to 60 years of age and was compared with culture and Gram stain. Using LPAT, an aetiological diagnosis could be done in 10 out of 65 (15.4%) cases of bacterial meningitis. In contrast, Gram stain and culture showed 16.9 and 23.1% positivity, respectively. LPAT correlated well with Gram stain and culture and can be recommended as an adjunct laboratory test for rapid aetiological diagnosis of bacterial meningitis for prompt institution of proper antibiotics.

Diagnóstico precoce das faringoamigdalites estreptocócicas: avaliação pelo teste de aglutinação de partículas de látex / Early diagnosis of streptococcal pharyngotonsillitis: assessment by latex particle agglutination test

OBJETIVOS: A faringoamigdalite aguda é uma das doenças mais freqüentes na prática pediátrica, sendo o estreptococo beta-hemolítico do grupo A (EBHGA) o agente etiológico bacteriano mais comum. O seu diagnóstico e tratamento adequados são importantes principalmente para a prevenção de seqüelas não-supurativas. Testes rápidos de detecção de antígenos do estreptococo do grupo A são uma ferramenta útil no diagnóstico das faringoamigdalites estreptocócicas, pela rapidez dos resultados, acurácia e baixo custo; no entanto, são pouco utilizados em nosso meio e pouco estudados em nosso país. O objetivo deste estudo foi avaliar a acurácia de um kit de teste rápido de detecção de antígeno do EBHGA comparado à cultura de suabe de orofaringe. MÉTODOS: Foram selecionadas crianças de 1 a 18 anos com diagnóstico clínico de faringoamigdalite aguda em serviços públicos de urgência e clínica privada de Belo Horizonte (MG), sendo excluídas as que haviam utilizado antibióticos até 30 dias antes da consulta. A amostra final incluiu 229 pacientes, que foram submetidos a coleta de dois suabes de orofaringe, um para o teste rápido para EBHGA e o outro enviado para cultura. RESULTADOS: Encontrou-se sensibilidade de 90,7 por cento, especificidade de 89,1 por cento, valor preditivo positivo de 72,1 por cento, valor preditivo negativo de 96,9 por cento e razão de verossimilhança positiva de 9,0 para o teste rápido utilizado comparado à cultura. CONCLUSÃO: O teste rápido utilizado apresentou boa correlação com a cultura, sendo, portanto, de grande utilidade na prática clínica para detecção do EBHGA.

OBJECTIVES: Acute pharyngitis is one of the most common diseases in pediatric practice, and the most common bacterial etiology is group A beta-hemolytic streptococcus (GABHS). Correct diagnosis and treatment are primarily of importance to the prevention of non-suppurative sequelae. Rapid tests for detecting the antigen of group A streptococcus are a useful tool for the diagnosis of streptococcal pharyngotonsillitis, due to the speed of results, accuracy and low cost; however, in our country they are little used and have been little studied. The objective of this study was to evaluate the accuracy of a GABHS rapid antigen detection test kit, in comparison with oropharynx swab culture. METHODS: Children aged 1 to 18 years with clinical diagnoses of acute pharyngitis were chosen at public emergency and private clinical services in Belo Horizonte, Minas Gerais, Brazil, with children being excluded if they had taken antibiotics within 30 days of their consultation. The final sample consisted of 229 patients, each of whom had two oropharynx swabs taken, one for rapid GABHS testing and the other to be sent for culture. RESULTS: We observed sensitivity of 90.7 percent, specificity of 89.1 percent, a positive predictive value of 72.1 percent, a negative predictive value of 96.9 percent and a positive likelihood ratio of 9.0 for the rapid test used here, compared with culture. CONCLUSIONS: The rapid test studied exhibited a good correlation with culture and is, therefore, of great use in clinical practice for detection of GABHS.

Comparisons of Latex Agglutination, Immunochromatography and Enzyme Immunoassay Methods for the Detection of Rotavirus Antigen / 대한진단검사의학회지

BACKGROUND: Rotavirus is the most common cause of childhood gastroenteritis during winter season. Rapid, accurate diagnosis is essential for preventing severe complications of rotaviral gastroenteritis. The sensitivity and specificity of five detection test kits for rotavirus including latex agglutination (LAT), enzyme immunoassay (EIA) and three immunochromatographic methods (ICG) were evaluated in this study. METHODS: A total of 95 stool samples collected from patients with acute gastroenteritis were studied. The test kits were as follows: LAT (Slidex latex, bioMerieux Vitek, France); three kinds of ICG (Dipstick ROTA, Eiken, Japan; SAS Rota Test, SA Scientific, Inc., USA; and ASAN Easy Test Rota strip, ASAN Pharmaceutical., Korea); and EIA (VIDAS Rotavirus, bioMerieux Vitek). The samples showing discordant results were reevaluated by reverse-transcription (RT) PCR and clinical manifestations. RESULTS: Of a total of 95 cases, 56 (58.9%) were positive and 39 (41.1%) were negative. Thirteen cases showed discordant results. Sensitivity and specificity were, respectively, 85.7% and 100% for LAT, 100% and 95% for both of Dipstick ROTA and SAS Rota, 86.7% and 87.5% for ASAN Rota strip and 98.1% and 97.3% for EIA. CONCLUSIONS: LAT was rapid and easy to perform and showed the lowest sensitivity among the five test kits. ICG showed a good agreement with EIA and RT-PCR. EIA was the best in respect of sensitivity and specificity, but difficulty in interpretations of equivocal results and time-consuming procedures were limitations. In conclusion, ICG, which is easy to perform at a low cost, may be an optimal method in place of LAT for the detection of rotavirus.

Evaluation of an in-house rapid diagnostic method for detection of Salmonella enterica serovar Typhi in fecal specimens.

Salmonella enterica serovar Typhi is the etiological agent of typhoid fever. Laboratory diagnosis requires isolation and identification of the organism from the patient's blood or feces. Feces is the specimen most commonly submitted to laboratories. Detection of bacterial antigens is an important adjunct to laboratory diagnosis. We carried out an in-house diagnostic method by preparing test reagents comprising of latex beads coated with specific antisera to detect Vi, O9 and H-d antigens of S. typhi. Fecal specimens from one hundred patients with diarrhea and fever as well as from twenty healthy controls were incubated for enrichment in Selenite F broth for 6 hours or overnight. Latex agglutination tests to detect antigens of S. typhi were carried out on centrifuged broth supernatants. Parallel cultures on media selective for S. typhi were also set up. Nine of the supernatants were positive for two or more specific antigens and S. typhi grew in three of the corresponding cultures. None of the samples from 20 healthy controls were positive by either the diagnostic method or by culture. The result of the in-house diagnostic assay can be obtained overnight and may help in directing immediate antimicrobial therapy.

Rapid detection of methicillin - resistant staphylococcus aureus [MRSA] by: disk diffusion, E-test, latex agglutination test and real -time PCR

Methicillin resistant Staphylococcus aureus [MRSA] is an important pathogen causing severe nosocomial infections whose prevalence has been increasing. The effectiveness of infection control measures is enhanced by early detection of resistant isolates and this is dependent on the time taken to isolate and identify MRSA In specimens taken from infected patients and in screening specimens taken to identify patients colonized with MRSA. So we aimed in this study to evaluate the abilities of phenotypic methods [Disk diffusion. E-test and Latex agglutination test] and genotypic method [real time PCR] for rapid detection of methicillin resistance in S. aureus. It was done on 220 patients [155 males and 65 females] at Benha University Hospital during the period from March to September 2005 to isolate any growth of S. aureus. Two hundred and twenty clinical samples were collected: they were 140 pus samples. 48 urine samples and 32 blood samples. Pus and urine samples and positive blood cultures were cultured to isolate any growth of S. aureus then the isolated colonies were examined for identification of MRSA isolates by disk diffusion method [Ox 1 micro g. Ox 5 micro g and Fox 30 micro g]. E-test. PBP2a latex agglutination test and detection of mecA gene by real time PCR. Two hundred isolates were detected in 220 clinical samples The frequency of S. aureus isolates was 28% [56 out of 200 isolates] they were mainly from wound pus [36 out of 56] The mec A PCR assay allowed us to classify 22[39.3%] of the isolates as S. aureus mec A-positive and they were mainly from pus [12 out of 22] and blood [6 out of 22]. and 34 [60.7%] as S aureus mecA negative. When phenotypic and genotypic identification was compared with PCR results it was found that by oxacillin 1 micro g disk, the sensitivity was 90.9% and the specificity was 94.1% by oxacillin 5 micro g disk, the sensitivity was 90.1% and the specificity was 76.5%, while cefoxittin 30 micro g disk yield 100% sensitivity and 94.1% specificity. Oxacillin E-test strips had the same sensitivity and specificity of oxacillin lmicrog disk. Latex agglutination test and real time PCR had the best sensitivity[100%] and specificity [100%] and they are able rapidly and reliably to detect MRSA isolates. the new molecular assay [real time PCR] was found to be rapid and robust because it is a largely automated assay. less hands on work is needed, consumes shorter time than conventional PCR and it can be used for direct detection of MRSA from non sterile clinical specimen, however, it is not yet available in the majority of routine diagnostic laboratories because of their elevated technical requirements. In absence of real time PCR. latex agglutination test is the best method for MRSA detection from isolated colonies

Resultados preliminares de la evaluación del primer sistema látex en el diagnóstico rápido de la leptospirosis humana en Cuba / Preliminary results of the evaluation of the first latex system in the rapid diagnosis of human leptospirosis in Cuba

Se elaboró un látex de aglutinación de producción nacional (leptospira - látex - IPK) para el diagnóstico rápido de la leptospirosis humana. La dilución óptima de trabajo del antígeno termorresistente (TR) acoplado a las partículas de látex fue de 1/80. Se emplearon partículas de látex comerciables de 0,8 µm. Se obtuvo una sensibilidad del 86,6 por ciento y una especificidad del 88,7. El índice de coincidencia entre el leptospira - látex - IPK y el lepto dri dot (estuche comercial) fue de un 85 por ciento. Al aplicar el método estadístico de X2, no existieron diferencias significativas entre el leptospira - látex-IPK, MAT (gold standard) y la hemaglutinación pasiva. Se obtuvo, de esta manera, el primer resultado biológico de látex en Cuba, útil en el diagnóstico rápido de la leptospirosis humana, el cual deberá ser evaluado en el terreno para determinar nuevos parámetros, entre ellos, la estabilidad y la reproducibilidad

Development and evaluation of a latex agglutination test for the rapid diagnosis of scrub typhus.

The purpose of this research was to develop a simple and rapid diagnostic test for scrub typhus using a latex agglutination test (LAT) to detect antibodies against Orientia tsutsugamushi. Five strains of O. tsutsugamushi were propagated in L929 cells. The rickettsiae were purified and concentrated with percoll density gradient centrifugation. A suitable concentration of O. tsutsugamushi soluble antigen was used to sensitize latex to prepare the latex antigen. The specificity, sensitivity, and accuracy of the latex antigen were assessed. The LAT, indirect immunofluorescent antibody test (IFA), and Weil-Felix agglutination test (WF) were compared by testing 109 acute febrile illness cases and 100 confirmed non-scrub typhus cases (50 other febrile disease cases and 50 healthy controls). By using the IFA as the standard reference method, the overall sensitivity, specificity, and accuracy of the LAT were 89.1, 98.2, and 93.6%, respectively. By contrast, the sensitivity of the WF, compared with the IFA, was only 47.3%, while the specificity and accuracy were 92.6 and 69.7%, respectively. Thus, the LAT described here is another important alternative test for the diagnosis of scrub typhus.

Diagnosis of neurotoxoplasmosis by antibody detection in cerebrospinal (CSF) fluid using Latex Agglutination Test and ELISA.

The present study was carried out to evaluate the utility of Anti-Toxoplasma gondii antibody detection in CSF specimens using Latex Agglutination Test (LAT) and Enzyme Linked Immunosorbent Assay (ELISA) for the diagnosis of NT. The study included CSF specimens from twenty-five HIV seropositive, autopsy proven (histopathological) cases of NT and 29 control cases with CNS diseases other than NT. All the specimens were subjected for antibody detection by LAT, IgG ELISA and IgM ELISA. Out of 25 CSF samples from autopsy proven cases of NT, LAT was positive in 48%, whereas ELISA for IgG antibody was positive in 92% of the cases. IgM antibodies were present in only one case that was also positive by LAT and IgG ELISA. None of the control CSF specimens showed anti-T. gondii antibodies either by LAT or ELISA. Detection of anti-T. gondii IgG antibodies in CSF can be a useful adjunct to the clinical and CT findings in the diagnosis of NT. IgG ELISA is more sensitive when compared to LAT. IgM antibody detection has a negligible value in the diagnosis of NT.

Latex agglutination test in the diagnosis of pyogenic meningitis.

Samples of cerebrospinal fluid (n=204) from pediatric patients with clinically suspected pyogenic meningitis were examined by direct microscopy, bacterial culture and Latex Agglutination Test (LAT). Latex Agglutination Test was done for detection of antigen of Streptococcus pneumoniae and Haemophilus influenzae type b. Among 38 LAT positive cases, culture and/or gram stain was positive in only 20 cases and 18 cases were detected exclusively by LAT. Besides, LAT was useful in detecting the pre-treated cases as 11 out of 55 samples from pre-treated cases were positive by LAT in comparison to culture and/or Gram stain which detected only 4 of 55 cases. LAT is simple, rapid and more reliable test.

Staphylococcus aureus meticilino resistente: detección de PBP 2' mediante la técnica de látex y evaluación de la resistencia asociada / Methicillin-resistant staphylococcus aureus: detection of PBP 2 'latex using the technique and evaluation of the resistance associated

El Staphylococcus aureus meticilino resistente representa un patógeno importante en infecciones nosocomiales y adquiridas en la comunidad. Su detección en el laboratorio es en ocasiones difícil motivado a factores tales como la presencia de cepas con patrones de resistencia cercana a los puntos de corte (borderline), heterorresistencia o problemas en la metodología. El objetivo del presente estudio fue la detección mediante la técnica de látex de la proteína PBP 2', responsable de la resistencia a meticilina en Staphylococcus aureus, y la evaluación de la resistencia asociada a antibióticos marcadores de este fenotipo de resistencia: clindamicina, gentamicina, eritromicina, tetraciclina y ciprofloxacina. Para cumplir el objetivo propuesto fueron evaluadas 65 cepas de Staphylococcus aureus meticilino resistente, aisladas entre octubre 2001 y diciembre 2003 a partir de muestras clínicas y conservadas en el cepario del Labortorio Metropolitano de Caracas. De las 65 cepas evaluadas, 30 (46,15 por ciento) mostraron heterorresistencia y 35 (53,85 por ciento) resistencia absoluta (homorresistencia). La resistencia asociada a los antibióticos evaluados fue la siguiente: clendamicina (49,2 por ciento), gentamicina (64,7 por ciento), eritromicina (67,7 por ciento), tetraciclina (46,2 por ciento) y ciprofloxacina (57,0 por ciento). En una de las cepas no se detectó la presencia de la proteína PBP2', pudiendo atribuirse la resistencia a oxacilina a la presencia de otras PBP modificadas o a la hiperproducción de beta lactamasa.