¿La detección de toxinas de Clostridioides difficile es necesaria cuando se detecta la enzima glutamato deshidrogenasa? / Is Clostridioides difficile toxins detection necessary when the glutamate dehydrogenase enzyme is detected?

Resumen Introducción: Clostridioides difficile causa diarrea y colitis pseudomembranosa. Su diagnóstico se realiza con la detección de glutamato-deshidrogenasa (GDH) o las toxinas A y B y se confirma con pruebas de amplificación de ácidos nucleicos. Objetivo: Definir si la determinación de GDH es redundante a la de las toxinas. Métodos: Estudio observacional retrospectivo de muestras fecales de pacientes con sospecha de infección por Clostridioides difficile. Las toxinas y GDH se determinaron mediante inmunocromatografía. Se realizó una simulación bayesiana con los cocientes de probabilidad; se consideró significativo un valor de p < 0.05. Resultados: Se analizaron 329 resultados de GDH y toxinas A y B. Se encontró una prevalencia de infección de Clostridioides difficile de 18.2 %. La sensibilidad y especificidad de la prueba de GDH fue de 0.90 y 0.89, respectivamente. El cociente de probabilidad positivo fue de 8.9 y el negativo, de 0.11. Conclusiones: Un resultado negativo de GDH disminuye considerablemente la probabilidad de infección, pero no la descarta. La detección de toxinas de Clostridioides difficile puede ser necesaria en instituciones donde la amplificación de ácidos nucleicos no es económica o accesible.

Abstract Introduction: Clostridioides difficile causes diarrhea and pseudomembranous colitis. Its diagnosis is made with glutamate dehydrogenase (GDH) or toxins A and B detection and is confirmed with nucleic acid amplification tests. Objective: To define if GDH determination is redundant to that of toxins. Methods: Retrospective, observational study in diarrheal stools of patients with suspected Clostridioides difficile infection. Toxins and GDH were determined by immunochromatography. Bayesian simulation was performed with likelihood ratios; a p-value < 0.05 was regarded as significant. Results: 329 GDH and toxin A and B results were analyzed. Clostridioides difficile infection prevalence was 18.2 %. Sensitivity and specificity of the GDH test were 0.90 and 0.89, respectively. Positive likelihood ratio was 8.9, and negative was 0.11. Conclusions: A negative GDH result considerably reduces the probability of infection but does not rule it out. Clostridioides difficile toxins detection may be necessary in institutions where nucleic acid amplification is not affordable or accessible.

Desarrollo y evaluación de una base de datos in house para la identificación rápida de Burkholderia contaminons por EM MALDI-TOF / Development and evaluation of an in-house database for quick identification of Burkholderia contaminans by MALDI-TOF MS

La espectrometría de masas (EM) (matrix assisted laser desorption ionization-time of flight) MALDI-TOF demostró ser una herramienta robusta para la identificación de numerosos grupos taxonómicos. No obstante, presenta limitaciones. Una ventaja clave de la técnica es la flexibilidad para la incorporación de espectros proteicos de microorganismos ausentes en la base de datos comercial. Dada la prevalencia de Burkholderia contaminans en los pacientes fibroquísticos en Argentina, y a que en ellos es crucial el diagnóstico microbiológico rápido y confiable, la EM MALDI-TOF surge como una herramienta estratégica. El objetivo del trabajo fue desarrollar una base de datos adicional con espectros peptídicos de aislamientos de referencia de B. contaminans. La misma demostró ser exitosa para la identificación del 97% de los aislamientos analizados. Por lo cual la EM MALDI-TOF con la base de datos extendida resultó ser una herramienta útil para la identificación y diferenciación de otras especies relacionadas a B. contaminans.

MALDI-TOF (matrix assisted laser desorption ionization-time of flight) mass spectrometry (MS) proved to be a robust tool for the identification of numerous taxonomic groups. However, it has limitations. A key advantage of this technique is the flexibility for the incorporation of protein profiles of microorganisms not included in the commercial database. Due to the prevalence of Burkholderia contaminans in fibrocystic patients in Argentina and the fact that rapid and reliable microbiological diagnosis is crucial in them, MALDI-TOF MS emerges as a strategic tool. The aim of this work was to develop an additional database with peptide spectra of reference isolates of B. contaminans. This database demonstrated to be successful for the identification of 97% of the isolates analyzed. Therefore, MALDI-TOF MS with the extended database was a useful tool for the identification and differentiation of other related species to B. contaminans.

Performance of rapid tests for carbapenemase detection among Brazilian Enterobacteriaceae isolates

ABSTRACT The global emergence of carbapenemases led to the need of developing new methods for their rapid detection. The aim of this study was to evaluate the performance of the rapid tests for carbapenemase-producing and non-producing Enterobacteriaceae. Carbapenem non-susceptible Enterobacteriaceae from a surveillance study submitted to a multiplex real time PCR for carbapenemase detection were included in this study. The isolates were subjected to the rapid phenotypic tests Carba NP, Blue-Carba and Carbapenem Inactivation Method (CIM). A total of 83 carbapenemase-producing (43) and non-producing (40) isolates were included in the study. The sensitivity/specificity were 62.7%/97.5%, 95.3%/100%, and 74.4%/97.5% for Carba NP, Blue-Carba and CIM, respectively. Both Carba NP and Blue-Carba presented their final results after 75 min of incubation; the final results for CIM were obtained only after 8 h. Failure to detect OXA-370 carbapenemase was the main problem for Carba NP and CIM assays. As the Blue-Carba presented the highest sensitivity, it can be considered the best screening test. Conversely, CIM might be the easiest to perform, as it does not require special reagents. The early detection of carbapenemases aids to establish infection control measures and prevent carbapenemases to spread reducing the risk of healthcare associated infections and therapeutic failure.

Performance of "RESIST-3 O.K.N. K-SeT" immunochromatographic assay for the detection of OXA-48 like, KPC, and NDM carbapenemases in Klebsiella pneumoniae in Turkey

ABSTRACT In this study, the performance of the "RESIST-3 O.K.N. K-SeT" (Coris BioConcept, Gembloux, Belgium) immunochromatographic assay was evaluated in 132 Klebsiella pneumoniae comprising 102 carbapenem resistant and 30 carbapenem susceptible isolates. Genotypically known isolates of Gram negative bacteria (n = 22) including various species were also tested by the assay as controls. The isolates tested by the immunochromatographic assay and also were run PCR for bla KPC, bla IMP, bla VIM, bla NDM, and bla OXA-48. The rates of bla NDM, bla OXA-48, and bla KPC in carbapenem resistant isolates were found at 52.9%, 39.2%, and 2.0%, respectively. Both bla NDM and bla OXA-48 were found in six (5.9%) isolates. The results of the assay showed 100% concordance with those obtained by PCR in 132 K. pneumoniae. The agreement between the two methods was found to be identical at the isolate level. The assay also correctly detected all genotypically known isolates of Escherichia coli, Serratia marcescens, Citrobacter freundii, Enterobacter cloacae, K. pneumoniae carrying bla KPC, bla NDM, and/or bla OXA-48. On the other hand, the assay did not exhibit any cross-reaction in control isolates harboring bla IMP and bla VIM. We conclude that the RESIST-3 O.K.N. K-SeT is a reliable, rapid, and user friendly test and we recommend it for routine diagnostic laboratories.

Caracterización de metalo-β-lactamasas en aislados clínicos de Pseudomonas aeruginosa recuperados de pacientes hospitalizados en el Hospital Militar Central / Characterization of metallo-β-lactamase in clinical isolates of Pseudomonas aeruginosa retrieved from patients hospitalized in the Central Military Hospital

Con el objetivo de caracterizar y determinar la frecuencia de genes que codifican metalo-β-lactamasas (MBL) en aislados clínicos de Pseudomonas aeruginosa (P. aeruginosa), se realizó un estudio transversal en el Hospital Militar Central (HMC) de Lima, Perú, entre enero y setiembre del 2016. Se analizaron 76 aislados de P. aeruginosa con sensibilidad disminuida a carbapenémicos y resistentes a ceftazidima. La detección fenotípica de MBL se realizó por el método de sinergia de doble disco entre imipenem y meropenem frente al ácido etilendiaminotetraacético (EDTA), y la identificación de los genes por reacción en cadena de la polimerasa. De los 76 aislados, 24 (31,6 %) fueron positivos para MBL por el método fenotípico, confirmándose genéticamente todos. Se encontró el gen blaIMP en 23/24 (95,8 %) y blaVIM en 1/24 (4,2 %). Ningún aislado presentó blaNDM. El gen blaIMP resultó ser el más frecuente entre los aislados clínicos de P. aeruginosa no sensibles a carbapenémicos en el HMC.

hat codify metallo-β-lactamases (MBL) in clinical isolates of Pseudomona aeruginosa (P. aeruginosa), a cross-sectional study was conducted in the Central Military Hospital (HMC) of Lima, Peru, between January and September, 2016. Seventy-six (76) isolates of P. aeruginosa with diminished sensitivity to carbapenemes and resistant to ceftazidime were analyzed. The phenotype detection of MBL was made by double disc synergy between imipenem and meropenem versus ethylenediaminetetraacetic acid (EDTA), and the identification of the genes was performed by polymerase chain reaction. Of the 76 isolates, 24 (31.6%) were positive for MBL by the phenotype method, genetically confirming all. The blaIMP gene was found in 23/24 (95.8%) and blaVIM in 1/24 (4.2%). No isolate had blaNDM. The blaIMP gene turned out to be the most frequent among clinical isolates of P. aeruginosa not sensitive to carbapenemics at this Hospital.

Production of recombinant flagellin to develop ELISA-based detection of Salmonella Enteritidis

ABSTRACT Food-borne diseases, caused by the pathogenic bacteria, are highly prevalent in the world. Salmonella is one of the most important bacterial genera responsible for this. Salmonella Enteritidis (SE) is one of the non-typhoid Salmonellae that can be transmitted to human from poultry products, water, and contaminated food. In recent years, new and rapid detection methods such as enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) have been developed. In this study, recombinant FliC (rFliC) was produced to be used as an antigen. The immunization was conducted in mice with the purified recombinant FliC (rFliC). The mice were subcutaneously immunized with rFliC and elicited significant rFliC specific serum IgG antibodies. An indirect ELISA system was established for the detection of Salmonella Enteritidis. Our results confirmed that the recombinant flagellin can be one of the excellent indicators for the detection of Salmonella Enteritidis.

Características de la infección por Clostridium difficile en una institución de alta complejidad y reporte de la circulación en Colombia de la cepa hipervirulenta NAP1/027 / Characteristics of Clostridium difficile infection in a high complexity hospital and report of the circulation of the NAP1/027 hypervirulent strain in Colombia

Resumen Introducción. Clostridium difficile es el principal responsable de la diarrea asociada al uso de antibióticos. En Colombia y en Latinoamérica, el conocimiento sobre el comportamiento epidemiológico de la infección por C. difficile todavía es limitado. Objetivo. Describir las características de una serie de pacientes con infección por C.difficile . Materiales y métodos. Se hizo un estudio descriptivo de una serie de casos de pacientes con infección por C. difficile atendidos en la Fundación Clínica Shaio, entre enero de 2012 y noviembre de 2015. Resultados. Se estudiaron 36 pacientes con una edad promedio de 65 años. Se determinaron los siguientes factores relacionados con la infección por C. difficile: uso previo de antimicrobianos (94,4 %), hospitalización en los últimos tres meses (66,7 %) y uso de inhibidores de la bomba de protones (50 %). Las comorbilidades más comunes fueron la enfermedad renal crónica (41,7 %) y la diabetes mellitus (30,6 %). Los síntomas más frecuentes fueron más de tres deposiciones diarreicas (97,1 %) y dolor abdominal (42,9 %). En cuanto a la gravedad de los casos, 44,4 % se clasificó como leve a moderado, 38,9 % como grave, y 11,1 % como complicado o grave. El método de diagnóstico más utilizado (63,8% de los pacientes) fue la identificación de la toxina mediante reacción en cadena de la polimerasa (PCR). La mortalidad global durante la hospitalización fue de 8 %. Se identificaron cuatro cepas del serotipo NAP1/027 y nueve muestras fueron positivas para la toxina binaria. Conclusión. La infección por C. difficile debe sospecharse en pacientes con deposiciones diarreicas y factores asociados tradicionalmente a esta enfermedad. Se reportó la circulación de cepas hipervirulentas del serotipo NAP1/027 en Colombia, lo cual debe enfrentarse con la vigilancia epidemiológica y el diagnóstico temprano.

Abstract Introduction: Clostridium difficile is the main pathogen related to healthcare-associated diarrhea and it is the cause of 20 to 30% of diarrhea cases caused by antibiotics. In Colombia and Latin America, the knowledge about the epidemiological behavior of this infection is limited. Objective: To describe the characteristics of a series of patients with C. difficile infection. Materials and methods: We performed a descriptive case series study of patients with C. difficile infection hospitalized in the Fundación Clínica Shaio from January, 2012, to November, 2015. Results: We analyzed 36 patients. The average age was 65 years. The risk factors associated with the infection were: previous use of antibiotics (94.4%), prior hospitalization in the last three months (66.7%) and use of proton pump inhibitors (50%). The most common comorbidities were chronic kidney disease (41.7%) and diabetes mellitus (30.6%). The most frequent symptoms were more than three loose stools per day (97.1%) and abdominal pain (42.9%). According to the severity of the disease, 44.4% of cases were classified as mild to moderate, 38.9% as severe, and 11.1% as complicated or severe. The detection of the toxin by PCR (GeneXpert) was the most common diagnostic procedure (63.8%). Global mortality during hospitalization was 8%. We identified four strains with serotype NAP1/027 and nine samples positive for binary toxin. Conclusion: Clostridium difficile infection should be suspected in patients with diarrhea and traditional risk factors associated with this disease. We report the circulation of the hypervirulent strain serotype NAP1/027 in Colombia, which should be countered with epidemiological surveillance and a prompt diagnosis.

Resultados de la vigilancia nacional de la resistencia antimicrobiana de enterobacterias y bacilos Gram negativos no fermentadores en infecciones asociadas a la atención de salud, Colombia, 2012-2014 / Results of the national surveillance of antimicrobial resistance of Enterobacteriaceae and Gram negative bacilli in health care-associated infections in Colombia, 2012-2014

Resumen Introducción. En el tercer trimestre de 2012, comenzó a operar el Sistema Nacional de Vigilancia de Resistencia Antimicrobiana en las infecciones asociadas a la atención en salud, con el fin de recabar y analizar la información referente al problema en Colombia. Objetivo. Describir los perfiles de resistencia y los resultados de la vigilancia por el laboratorio con base en los datos recolectados en el Sistema. Materiales y métodos. Se hizo un estudio descriptivo y retrospectivo con base en la información del Sistema Nacional de Vigilancia en Salud Pública, Sivigila, 1 de septiembre de 2012 a 31 de diciembre de 2014, así como de las bases de datos Whonet con los datos notificados por las unidades primarias generadoras de datos y los resultados de la confirmación por el laboratorio de la caracterización fenotípica y genotípica de la resistencia a carbapenemasas en 1.642 aislamientos (927 de enterobacterias, 614 de Pseudomonas spp. y 101 de Acinetobacter spp.). Resultados. La resistencia de Escherichia coli a las cefalosporinas de tercera generación presentó un incremento significativo, alcanzando 26,3 % en unidades de cuidados intensivos y 22,5 % en otras áreas de hospitalización. La resistencia a ertapenem de Klebsiella pneumoniae registró un incremento y alcanzó 14,6 % en unidades de cuidados intensivos. La resistencia de Acinetobacter baumannii a los carbapenémicos superó el 50 % en dichas unidades, en tanto que en Pseudomonas aeruginosa se presentaron porcentajes más bajos (38,8 %). Las carbapenemasas más frecuentes en enterobacterias fueron la KPC (n=574), seguida de la NDM (n=57); en P. aeruginosa, la VIM (n=229) y la KPC (n=114), y en A. baumannii, la OXA-23 (n=87). Se detectaron varias combinaciones de carbapenemasas, siendo la de KPC y VIM la más frecuente en Pseudomonas spp., y en enterobacterias. Conclusión. La información obtenida a partir del Sistema Nacional de Vigilancia ha permitido conocer los perfiles y los mecanismos de resistencia a carbapenémicos de las cepas que están circulando en las instituciones de salud del país.

Abstract Introduction: The Colombian National Antimicrobial Resistance Monitoring System for the surveillance of healthcare-associated infections was set up to meet this problem in the third quarter of 2012. Objective: To describe resistance profiles and laboratory-based surveillance based on the information collected by the System. Materials and methods: We conducted a retrospective and descriptive study of the information notified to the Colombian Public Health Surveillance System (Sivigila), and in the Whonet databases covering the period from July 2012 to December 2014 provided by the primary data-generating units in the country, as well as laboratory surveillance results from 1,642 phenotypic and genotypic tests on carbapenemase isolates (927 from Enterobacteriaceae, 614 from Pseudomonas spp. and 101 from Acinetobacter spp.). Results: There was a significant increase in Escherichia coli resistance to third-generation cephalosporins (reaching 26.3% in ICUs and 22.5% in other hospital wards), and Klebsiella pneumoniae resistance to ertapenem also increased (reaching 14.6% in ICUs). Acinetobacter baumannii carbapenem resistance exceeded 50% in ICUs whereas Pseudomonas aeruginosa had lower carbapenem resistance (38.8%). KPC (n = 574) and NDM (n=57) were the most frequently occurring carbapenemases in Enterobacteriaceae, VIM (n=229) and KPC (n=114) in P. aeruginosa, and OXA-23 in A. baumannii (n=87); several carbapenemase combinations were identified, KPC + VIM being the most common in Pseudomonas spp. and Enterobacteriaceae. Conclusion: The data from the surveillance of healthcare-associated infections revealed significant carbapenem resistance profiles and antimicrobial resistance mechanisms circulating in Colombian healthcare institutions.

Modified Carba NP test for the detection of carbapenemase production in gram-negative rods: optimized handling of multiple samples

Abstract The modified Carba NP test presented here may be a valuable tool for laboratories interested in investigating a large number of carbapenemase-producing bacteria in a less-costly way. The test was evaluated against 48 carbapenemase-producing and carbapenemase-non-producing gram-negative bacteria. No false–positive results were obtained, but false-negative results were observed with OXA-23- and GES-carbapenemase-producing isolates. Aeromonas sp. are not testable by Modified Carba NP.

The virulence of Streptococcus pneumoniae partially depends on dprA

Abstract Streptococcus pneumoniae is one of the most frequent opportunistic pathogens worldwide. DNA processing protein A (DprA) is an important factor involved in bacterial uptake and DNA integration into bacterial genome, but its role in S. pneumoniae virulence remains unclear. The aim of this study was to characterize the effects of the pneumococcal dprA gene on the pathogenesis of S. pneumoniae. To construct a dprA-deficient pneumococcal strain, the dprA gene of the S. pneumoniae strain D39 was inactivated. The virulence of this dprA-deficient strain, designated ΔD39, was compared with that of the wild-type strain by evaluating their respective capabilities to adhere to human pulmonary epithelial cells (PEC-A549) and by analyzing their choline-binding protein expression levels. In addition, the expression profiles of genes associated with virulence and host survival assays were also conducted with the mutant and the wild-type strain. Our results indicate that the capability of ΔD39 to adhere to the PEC-A549 airway cells was significantly lower (p < 0.01) compared with D39. Additionally, the 100-KD choline-binding protein was not detected in ΔD39. The addition of competence-stimulating peptide (CSP) lead to a significantly reduction of psaA mRNA expression in the dprA-deficient mutant and an increased level of psaA transcripts in the wild-type strain (p < 0.01). The median survival time of mice intraperitoneally infected with ΔD39 was significantly higher (p < 0.01) than that of mice infected with D39. The results of this study suggest that DprA has a significant effect on virulence characteristics of S. pneumoniae by influencing the expression of choline-binding protein and PsaA.

Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation

Abstract Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case–control study in the Uberlândia Federal University – Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-β-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-β-lactamases genes.

Comparisons of IgA response in saliva and colostrum against oral streptococci species

Abstract The present study compared IgA specificity against oral streptococci in colostrum and saliva samples. Sixty-two mother-and-child pairs were included; samples of colostrum (C) and saliva (MS) were collected from the mothers and saliva samples were collected from babies (BS). The specificity of IgA against Streptococcus mutans and S. mitis were analyzed by western blot. Only 30% of babies’ samples presented IgA reactivity to S. mutans, while 74 and 80% of MS and C, respectively, presented this response. IgA reactivity to S. mutans virulence antigens (Ag I/II, Gtf and GbpB) in positive samples showed differences between samples for Gtf and especially for GbpB (p < 0.05), but responses to Ag I/II were similar (p > 0.05). The positive response of Gtf-reactive IgA was different between C (90%) and MS (58%) samples (p < 0.05), but did not differ from BS (p > 0.05). GbpB was the least detected, with 48 and 26% of C and MS, and only 5% of BS samples presenting reactivity (p > 0.05). Eight percent of MS and C samples presented identical bands to SM in the same time-point. In conclusion, the differences of IgA response found between C and MS can be due to the different ways of stimulation, proliferation and transportation of IgA in those secretions. The colostrum has high levels of IgA against S. mutans virulence antigens, which could affect the installation and accumulation process of S. mutans, mainly by supplying anti-GbpB IgA to the neonate.

Isolation of recombinant antibodies directed against surface proteins of Clostridium difficile

Abstract Clostridium difficile has emerged as an increasingly important nosocomial pathogen and the prime causative agent of antibiotic-associated diarrhoea and pseudomembranous colitis in humans. In addition to toxins A and B, immunological studies using antisera from patients infected with C. difficile have shown that a number of other bacterial factors contribute to the pathogenesis, including surface proteins, which are responsible for adhesion, motility and other interactions with the human host. In this study, various clostridial targets, including FliC, FliD and cell wall protein 66, were expressed and purified. Phage antibody display yielded a large panel of specific recombinant antibodies, which were expressed, purified and characterised. Reactions of the recombinant antibodies with their targets were detected by enzyme-linked immunosorbent assay; and Western blotting suggested that linear rather than conformational epitopes were recognised. Binding of the recombinant antibodies to surface-layer proteins and their components showed strain specificity, with good recognition of proteins from C. difficile 630. However, no reaction was observed for strain R20291—a representative of the 027 ribotype. Binding of the recombinant antibodies to C. difficile M120 extracts indicated that a component of a surface-layer protein of this strain might possess immunoglobulin-binding activities. The recombinant antibodies against FliC and FliD proteins were able to inhibit bacterial motility.

Correlations between the CagA Antigen and Serum Levels of Anti-Helicobacter pylori IgG and IgA in Children

We tested correlations between anti-Helicobacter pylori IgG and IgA levels and the urease test, anti-CagA protein antibody, degree of gastritis, and age. In total, 509 children (0-15 years) were enrolled. Subjects were stratified as 0-4 years (n = 132), 5-9 years (n = 274), and 10-15 years (n = 103) and subjected to the urease test, histopathology, ELISA, and western blot using whole-cell lysates of H. pylori strain 51. The positivity rate in the urease test (P = 0.003), the degree of chronic gastritis (P = 0.021), and H. pylori infiltration (P < 0.001) increased with age. The median titer for anti-H. pylori IgG was 732.5 IU/mL at 0-4 years, 689.0 IU/mL at 5-9 years, and 966.0 IU/mL at 10-15 years (P < 0.001); the median titer for anti-H. pylori IgA was 61.0 IU/mL at 0-4 years, 63.5 IU/mL at 5-9 years, and 75.0 IU/mL at 10-15 years (P < 0.001). The CagA-positivity rate was 26.5% at 0-4 years, 36.5% at 5-9 years, and 46.6% at 10-15 years for IgG (P = 0.036), and 11.3% at 0-4 years, 18.6% at 5-9 years, and 23.3% at 10-15 years for IgA (P < 0.001). Anti-H. pylori IgG and IgA titers increased with the urease test grade, chronic gastritis degree, active gastritis, and H. pylori infiltration. Presence of CagA-positivity is well correlated with a high urease test grade and high anti-H. pylori IgG/IgA levels.

New monoclonal antibody-based test for Helicobacter pylori urease in gastric tissue

BACKGROUND/AIMS: To evaluate a new monoclonal antibody for Helicobacter pylori urease in gastric tissue. METHODS: A total of 107 volunteers were enrolled. All subjects underwent a 13C-urea breath test and esophagogastroduodenoscopy. Gastric aspirates were analyzed for pH and ammonia. Six biopsy specimens in the gastric antrum and body were obtained for a rapid urease test and histology. The new monoclonal antibody-based H. pylori urease test (HPU) was performed to rapidly and qualitatively detect urease in two biopsy specimens. RESULTS: H. pylori infection was diagnosed in 73 subjects. The sensitivity and specificity of the HPU was 89% and 74%, respectively. The subjects were divided into two groups: one with true-positive and true-negative HPU results (n = 90) and the other with false-positive and false-negative HPU results (n = 17). Across all subjects, ammonia levels were 900.5 +/- 646.7 and 604.3 +/- 594.3 mumol/L (p > 0.05), and pH was 3.37 +/- 1.64 and 2.82 +/- 1.51 (p > 0.05). Sensitivity was higher in the presence of atrophic gastritis or intestinal metaplasia. CONCLUSIONS: HPU detected H. pylori in approximately 10 min. Gastric aspirate ammonia and pH levels did not affect the test results. Sensitivity was good in the presence of atrophic gastritis or intestinal metaplasia.

Concordancia entre procedimientos diagnósticos invasivos para la infección por Helicobacter pylori en adultos / Concordance among invasive diagnostic procedures for Helicobacter pylori infection in adults

Objetivo. Comparar la concordancia entre cultivo, histología y prueba rápida de la ureasa para el diagnóstico de infección por Helicobacter pylori, así como la relación de hallazgos histopatológicos y frecuencia de positividad entre dichos procedimientos diagnósticos. Material y métodos. Estudio de pruebas diagnósticas. Población de sujetos con endoscopía digestiva y toma de muestras gástricas antrales en un hospital de especialidades en México. Se realizó prueba rápida de la ureasa (una muestra), histología (dos muestras) y cultivo (dos muestras). Análisis estadístico con coeficiente de Kappa. Resultados. Se estudiaron 108 sujetos: 28 (25.9%) hombres y 80 (74.1%) mujeres; la edad promedio fue 49.1 (DE 15.1) años. El coeficiente de Kappa fue 0.729 y 0.377 entre cultivo con histología y prueba rápida de la ureasa respectivamente; asimismo, el coeficiente de Kappa fue 0.565 entre histología y prueba rápida de la ureasa. Conclusiones. La fuerza de concordancia fue mayor entre histología con cultivo y la prueba rápida de la ureasa, por lo cual la histología es lo más recomendable en la práctica clínica para la detección de la infección por Helicobacter pylori.

Objective. Compare the strength of concordance between culture, histology, rapid urease test for diagnosis of Helicobacter pylori infection and histopathological findings relationship and frequency of positivity among such diagnostic procedures. Materials and methods. Diagnostic test study. The study population were subjects with endoscopy and take samples of gastric antral. Rapid urease test (one sample), histology (two samples) and culture (two samples), and histopathological findings of gastric mucosa were performed. Statistical design with Student's t, Fisher exact test, Kappa coefficient. Results. We reviewed 108 subjects, 28 (25.9%) men, 80 (74.1%) women, mean age was 49.1 years (SD 15.1). The Kappa coefficient was 0.729 and 0.377 between culture with histology and rapid urease test, respectively; likewise the Kappa coefficient was 0.565 between histology and rapid urease test. Conclusions. The strength of concordance was higher between histology with culture and rapid urease test; the most recommended being histology in clinical practice for the detection of Helicobacter pylori infection.

Distribution of extended-spectrum β-lactamase types in a Brazilian tertiary hospital

INTRODUCTION: Epidemiological data on the prevalence of extended-spectrum β-lactamases (ESBLs) are scarce in Brazil despite the fact that these data are essential for empirical treatment and control measures. The objective of this study was to evaluate the prevalence of different ESBLs by type and distribution in a tertiary hospital in southern Brazil. METHODS: We evaluated 1,827 enterobacterial isolates between August 2003 and March 2008 isolated from patients at a tertiary hospital. Samples were identified using a Vitek automated system and were confirmed by biochemical testing. The identified ESBL strains were characterized by phenotypic methods, polymerase chain reaction (PCR), and sequencing. Genetic similarities were evaluated by pulsed-field gel electrophoresis. RESULTS: It was 390 (21.3%) ESBL-producing strains, which expressed the ESBLs CTX-M (292), SHV (84), CTX and SHV (10), TEM (2), and PER (2). CONCLUSIONS: The prevalence of ESBL-expressing strains was high, especially in Klebsiella pneumoniae and Enterobacter spp. CTX-M was the predominant type of ESBL observed, and its genetic variability indicates a polyclonal distribution. .