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ABSTRACT Objective: Ventilator-associated pneumonia (VAP) is the leading type of hospital-acquired infection in ICU patients. The diagnosis of VAP is challenging, mostly due to limitations of the diagnostic methods available. The aim of this study was to determine whether antibody-coated bacteria (ACB) evaluation can improve the specificity of endotracheal aspirate (EA) culture in VAP diagnosis. Methods: We conducted a diagnostic case-control study, enrolling 45 patients undergoing mechanical ventilation. Samples of EA were obtained from patients with and without VAP (cases and controls, respectively), and we assessed the number of bacteria coated with FITC-conjugated monoclonal antibodies (IgA, IgM, or IgG) or an FITC-conjugated polyvalent antibody. Using immunofluorescence microscopy, we determined the proportion of ACB among a fixed number of 80 bacteria. Results: The median proportions of ACB were significantly higher among the cases (n = 22) than among the controls (n = 23)-IgA (60.6% vs. 22.5%), IgM (42.5% vs. 12.5%), IgG (50.6% vs. 17.5%), and polyvalent (75.6% vs. 33.8%)-p < 0.001 for all. The accuracy of the best cut-off points for VAP diagnosis regarding monoclonal and polyvalent ACBs was greater than 95.0% and 93.3%, respectively. Conclusions: The numbers of ACB in EA samples were higher among cases than among controls. Our findings indicate that evaluating ACB in EA is a promising tool to improve the specificity of VAP diagnosis. The technique could be cost-effective and therefore useful in low-resource settings, with the advantages of minimizing false-positive results and avoiding overtreatment.
RESUMO Objetivo: A pneumonia associada à ventilação mecânica (PAVM) é o principal tipo de infecção adquirida no ambiente hospitalar em pacientes em UTIs. O diagnóstico de PAVM é desafiador, principalmente devido a limitações dos métodos diagnósticos disponíveis. O objetivo deste estudo foi determinar se a avaliação de bactérias revestidas por anticorpos (BRA) pode melhorar a especificidade de culturas de aspirado traqueal (AT) no diagnóstico de PAVM. Métodos: Estudo diagnóstico caso-controle envolvendo 45 pacientes sob ventilação mecânica. Amostras de AT foram obtidas de pacientes com e sem PAVM (casos e controles, respectivamente), e verificamos o número de bactérias revestidas com anticorpos monoclonais conjugados com FITC (IgA, IgM ou IgG) ou anticorpo polivalente conjugado com FITC. Utilizando microscopia de imunofluorescência, foi determinada a proporção de BRA em um número fixo de 80 bactérias. Resultados: A mediana das proporções de BRA foi significativamente maior nos casos (n = 22) que nos controles (n = 23) - IgA (60,6% vs. 22,5%), IgM (42,5% vs. 12,5%), IgG (50,6% vs. 17,5%) e polivalente (75,6% vs. 33,8%) - p < 0,001 para todos. A acurácia dos melhores pontos de corte para o diagnostico de PAVM em relação aos BRA monoclonais e polivalentes foi > 95,0% e > 93,3%, respectivamente. Conclusões: O número de BRA em amostras de AT foi maior nos casos que nos controles. Nossos achados indicam que a avaliação de BRA no AT é uma ferramenta promissora para aumentar a especificidade do diagnóstico de PAVM. A técnica pode ser custo-efetiva e, portanto, útil em locais com poucos recursos, com as vantagens de minimizar resultados falso-positivos e evitar o tratamento excessivo.
Subject(s)
Male , Female , Adult , Middle Aged , Aged , Antibodies, Bacterial/isolation & purification , Antibodies, Monoclonal/isolation & purification , Bacteria/isolation & purification , Pneumonia, Ventilator-Associated/diagnosis , Pneumonia, Ventilator-Associated/microbiology , Trachea/microbiology , Trachea/metabolism , Antibodies, Monoclonal/immunology , Bacterial Load , Bacteria/immunology , Intensive Care Units , Reference Values , Reproducibility of Results , Sensitivity and Specificity , Statistics, NonparametricABSTRACT
Objective To investigate the clinical significance of serum anti-Saccharomyces cerevisias antibody (ASCA),anti-outer membrane porin C (anti-OmpC),antibody to Pseudomonas fluorescens-associated sequence I2 (anti-I2 )and antibody to bacterial flagellin (anti-CBirl )in the diagnosis and treatment of inflammatory bowel disease (IBD).Methods From 2011 to 2013,87 patients with IBD were enrolled and divided into Crohn′s disease (CD)group (66 cases)and ulcerative colitis (UC)group (21 cases).A total of 62 age and gender matched healthy individuals were enrolled as the control group. Fasting blood samples (2 mL)of the subjects were collected.The expression of ASCA,anti-OmpC,anti-I2 and anti-Cbirl antibodies was detected with enzyme-linked immunosorbent assay (ELISA)kits.The diagnosis value of each antibody in IBD and the differential diagnostic value of in UC and CD were compared by receiver operating characteristic (ROC)curve.Results The area under the curve (AUC)of ASCA between IBD and the healthy control group,between CD group and UC group was 0.580 and 0.512, respectively;the accuracy in diagnosis was low.The AUC of anti-CBirl between IBD and the healthy control group was 0.617.There was no differential diagnosis significance of the other antibodies.The positive rate of ASCA in IBD group was 62.1 % (54/87),which was significantly higher than that in the control group (38.7%,24/62).The positive rates of anti-OmpC and anti-I2 in IBD group was significantly lower than those in the control group and the differences were statistically significant (both P 0.05).The specificity,sensitivity,positive predictive value (PPV)and negative predictive value (NPV)of ASCA in differential diagnosis of CD and UC was 52.4%,66.7%,81 .48% and 33.33%,respectively.The specificity and sensitivity of anti-OmpC,anti-I2 and anti-CBirl in differential diagnosis of CD and UC was 81 .0% to 100.0% and 9.1 % to 37.9%,respectively.The specificity,sensitivity,PPV and NPV of double-positive ASCA and anti-I2 in the diagnosis of CD was 57.1 %,86.4%,82.6% and 50.0%, respectively.The positive rate of ASCA and anti-I2 in CD group was significantly higher than that in UC group (84.8%(56/66)vs 57.1 % (12/21 );χ2 =5 .633,P =0.018 ).Conclusions Positive ASCA has some significance in the diagnosis of patients with IBD in our country.The detection of anti-I2 can help to diagnose ASCA negative CD.Because of low sensitivity and positive rate,anti-OmpC and anti-CBirl have limited value in the diagnosis of IBD and the differential diagnosis of UC and CD in our country.
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Objective To evaluate the specificity of Architect chemiluminescence immunoassay ( CLIA) for diagnosis of syphilis in the clinical screening test.Methods 65 774 syphilis specific antibody results in the Beijing Tongren Hospital were retrospectively analyzed.In this study, Architect CLIA for diagnosis of syphilis was used as a screening test for the pre-operative patients from August 2011 to July 2012.All the repeatedly reactive samples were tested by the tolulized red unheated serum test ( TRUST) and Treponema pallidum particle agglutination ( TPPA) assay.Samples with with discordant results were verified by western blot ( WB) Finally, all the results were statistically analyzed by software SPSS 17.0.Results Among 65 774 samples, 940 (1.43%) were found to be repeatedly reactive using the Architect CLIA.Of these sera, 330 ( 35.11%) were reactive and 610 ( 64.89%) were nonreactive by TRUST.Because a TRUST titer of 1:1was not always sufficient to confirm a TPPA reactive result, all the samples with CLIA reactive results were finally performed by TPPA assays.The results showed that 843 ( 89.68%) were positive and 97 (10.32%) were negative.After arbitrated by the WB, out of 97 TPPA negative sera, 18 (18.56%) were positive;7(7.22%) were indeterminate and 72(74.23%) were negative.Conclusions The specificity of Architect CLIA for diagnosis of syphilis was 99.89%.The results showed that confirmation by TPPA on sera with screening test for syphilis by Architect CLIA effectively decreased the false-positive results and could be suitable for a routine supplementary for syphilis.However, if necessary, the WB should be further utilized.
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Objective To analyze the results of syphilis serology test among inpatients and to provide information for the control of syphilis.Methods Syphilis serology test results of inpatients from Jan.2010 to Nov.2012 in a tertiary general hospital were collected and retrospectively analyzed.The serum samples were screened by Treponema pallidum (TP) antibody enzyme linked immunosorbent assay (ELISA) and syphilis toluidine red unheated serum reagin test (TRUST) simultaneously.The TP-ELISA positive samples were confirmed by Treponema pallidum particle agglutination test (TPPA).Difference of measurement data was compared with analysis of variance.Results A total of 81 946 cases were collected,among which 1618 cases were positive of anti-TP.The positive rate of anti-TP was 2.27％ in the year 2010,1.58％ in 2011,and 2.11％ in 2012.For male and female patients,the positive rates of anti-TP were 2.38％ and 1.69％,respectively (x2 =48.97,P=0.00).The positive rates of anti-TP in the age groups of ≤19 years,20-39 years,40-59 years,60-79 years,and ≥80 years were 2.83％,0.94％,2.14％,2.37％,and 3.63％,respectively.The titer of TRUST was relatively lower in anti-TP positive inpatients.The anti-TP positive patients with TRUST titer ＜ 1∶8 accounted for 84.65％ in the age group of ≤19 years,79.69％ in the 20-39 years group,81.69％ in the 40-59 years group,86.12％ in the 60-79 years group,and 87.45％ in the age group of ≥80 years.The highest anti-TP positive rate (3.63％) was observed in the age group of ≥80 years with the lowest percentage (12.55 ％) of TRUST titer ≥1∶8.The lowest anti-TP positive rate (0.94％) was observed in the 20-39 years group with the highest percentage (20.31％) of TRUST titer ≥1∶8.Conclusions The characteristics of syphilis serological positivity vary depending on genders and ages.The prevention and control measures for syphilis should be strengthened,especially in the senior population.
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ObjectiveTo analyze the seroepidemiologic of Mycoplasma pneumoniae infection and evaluate antibiotics medication of some positive patients by follow-up. Methods Serodia-MycolⅡ particle agglutination assay was used to detect serum antibodies against Mycoplasma pneumoniae in 3 134 clinically suspected infections. Mycoplasma pneumoniae infection was determined and seroepidemiologic was analyzed by results of the test, including positive antibody rates in whole subjects, in male or female groups, in different seasons or age groups as well as in different sources. Evaluate antibiotics medication of some positive patients by follow-up. The average days of medication were counted, different antibiotics medication and medication effect were analyzed. Results In 3 134 serum samples from clinically suspected Mycoplasma pneumoniae infections, 350 ( 11.2％ ) were tested with positive antibodies. The positive antibody rate in female patients was 12. 3％ ( 198/1 604), which was higher than 9. 9％ ( 152/1 530) in males (X2 =4. 58,P ＜0. 05). The peak season was found in the fourth quarter (October-December) with 13.2％ of positive antibody and the highest positive rate (32. 8％, 45/137 ) was found in school aged (5 -9 years old )children. Samples from pediatrics clinic and ward were tested to have highest positive rates ( 27. 9％ and 26. 5％, respectively ), comparing that from other sources. Infection due to Mycoplasma pneumoniae was identified in 28％ (7/25) of community-acquired pneumonia (CAP) patients, which is higher than other diseases. Based on the follow-up of 91 antibody positive patients, between 5 to 120 days ( mean 24. 2 days )were counted from appearance of clinical symptoms to clinic visiting/testing. 71 of 91 (78. 0％ ) patients was medicated with macrolide antibiotics, 4 (4. 4％ ) with quinolones, 4 (4. 4％ ) with cephalosporin, and the rest 12 ( 13.2％ ) patients were medicated with other antibiotics or only symptomatic treatment. The average period of antibiotics medication was between 3 to 21 days (mean 8. 2 days). Medication effect results by follow-up were cure in 35 ( 38. 5％ ), improvement in 50 (54. 9％ ), and poor responses in 6 (6. 6％ ).ConclusionsMycoplasma pneumoniae positive rate in female patients was higher than in males, and peak rate was found in the fourth quarter and in school aged children. Samples from pediatrics clinic and ward were tested to have highest positive rates. Physicians could choose first line antibiotics according to laboratory test results of Mycoplasma pneumoniae, and gain good effect.
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Objective To express major outer membrane protein (MOMP) of Chlamydia trachomatis E and to prepare rabbit polyclonal antibody. Methods The recombinant plasmid MOMP/ pGEX6p-l prepared by our lab was introduced into E. coli. The protein was expressed and purified by gel recycling, then was injected into New Zealand rabbits to produce polyclonal antibodies. Enzyme linked immunosorbent assay (ELISA) was used to detect the titer of antibody. The antibody specificity was identified by Western blot and immunofluorescence. Results The fusion recombinant protein glutathione S-transferase (GST)-MOMP was successfully expressed in E. coli. The titer of antibody recombinant protein detected by Western blot and to the endogenous MOMP of Chlamydia trachomatis in vitro detected by immunofluorescence. Conclusions The recombinant MOMP is successfully expressed and the MOMP antibody with high titer and high specificity is obtained. which will be helpful for Chlamydia trachomatis detection and related clinical research.
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O PGL-I, antígeno de superfície do Mycobacterium leprae, é responsável pela ativação da resposta imunológica nos indivíduos que entram em contato com o bacilo. Os testes sorológicos anti PGL-I são utilizados como ferramenta para identificação de indivíduos expostos, com infecção subclínica ou com risco de adoecerem e quando associados à clínica podem auxiliar no diagnóstico da hanseníase, além de serem úteis para a classificação da forma clínica, pois apresentam alta sensibilidade nos pacientes multibacilares. A prevalência de soropositividade do teste pode refletir aproximadamente a taxa de exposição/infecção em uma população. O objetivo do estudo foi analisar a prevalência da infecção pelo M. leprae na população da Microrregião de Almenara, Minas Gerais. Para tanto, optou-se por estudo epidemiológico, do tipo survey, com uma amostra de 2726 indivíduos selecionados, aleatoriamente, a partir da estratificação dos setores censitários segundo quartis de taxa média de detecção, nos municípios de Almenara, Felisburgo, Jacinto, Jequitinhonha, Monte Formoso, Ponto dos Volantes, Santa Maria do Salto e Santo Antônio do Jacinto. Foram realizadas visitas domiciliares para aplicação de questionário estruturado para a obtenção de dados sócio-demográficos, de condições de moradia, de contato com doentes de hanseníase e de imunoprofilaxia, sendo também realizada coleta de sangue em papel filtro para análise anti PGL-I. O método imunoenzimático utilizado para análise sorológica foi o ELISA. O estudo foi aprovado pelo COEP-UFMG parecer nº ETIC 158/09 e atende às determinações da Resolução 196/96 do Conselho Nacional de Saúde. Os dados foram lançados no Epi Info v. 3.5.1 e analisados no software Statistical Package for the Social Sciences (SPSS) for Windows 18. Obteve-se soroprevalência média de anti PGL-I de 1,03% e verificou-se associação estatística entre a variável idade e a soropositividade anti PGL-I, sendo que os indivíduos com idade entre 15 e 29 anos apresentam...
The PGL-I surface antigen of Mycobacterium leprae, is responsible for activation of the immune response in individuals who come into contact with the bacillus. The serological anti PGL-I tests are used as a tool for identification of exposed individuals with subclinical infection or risk of disease and when associated to the clinic can help in the diagnosis of leprosy, besides they are useful for classifying the clinical form, since they have high sensitivity in multibacillary patients. The prevalence of seropositivity of the test may reflect approximately the rate of exposure / infection in a population. The purpose of this study was to analyze the prevalence of infection with M. leprae in the population of the microregion of Almenara, Minas Gerais. Hence, we opted for an epidemiological study, survey type, with a sample of 2726 individuals, randomly selected, from the stratification of census tracts, the second quartile, of average detection rate in the municipalities of Almenara, Felisburgo, Jacinto, Jequitinhonha, Monte Formoso, Ponto dos Volantes, Santa Maria do Salto e Santo Antônio do Jacinto. We carried out home visits to the enforcement of a structured questionnaire to obtain socio-demographic data, housing conditions, contact with patients of leprosy and of immunoprophylaxis, being also performed blood collection on filter paper for analysis of anti PGL-I. The immunoenzymatic method used for serological analysis was ELISA. The study was approved by the COEP-UFMG opinion nº ETIC 158/09 and meets the provisions of Resolution 196/96 of the National Health Council. The data entered into Epi Info v. 3.5.1 and analyzed using the Statistical Package for the Social Sciences 18 (SPSS) for Windows. We obtained an average seroprevalence of anti PGL-I of 1.03% and there was statistical association between age and anti PGL-I seropositivity, given that individuals aged between 15 and 29 years have approximately three times greater chance...