Rapid antibiotic susceptibility testing (RAST) of blood cultures in enterobacteria with inducible chromosomal AmpC-type ß-lactamase.

INTRODUCTION: Early and adequate treatment of bloodstream infections decreases patient morbidity and mortality. The objective is to develop a preliminary method for rapid antibiotic susceptibility testing (RAST) in enterobacteria with inducible chromosomal AmpC. METHODS: RAST was performed directly on spiked blood cultures of 49 enterobacteria with inducible chromosomal AmpC. Results were read at 4, 6 and 8h of incubation. Commercial broth microdilution was considered the reference method. Disks of 10 antibiotics were evaluated. RESULTS: The proportion of readable tests at 4h was 85%. All RAST could be read at 6 and 8h. For most antibiotics, the S or R result at 4, 6 and 8h was greater than 80% after tentative breakpoints were established and Area of Technical Uncertainty was defined. CONCLUSIONS: This preliminary method seems to be of practical use, although it should be extended to adjust the breakpoints and differentiate them by species.

Rapid antibiotic susceptibility testing (RAST) of blood cultures in enterobacteria with inducible chromosomal AmpC-type B-lactamase / Pruebas rápidas de sensibilidad antibiótica de hemocultivos con enterobacterias portadoras de B-lactamasa tipo AmpC cromosómica inducible

Introduction: Early and adequate treatment of bloodstream infections decreases patient morbidity and mortality. The objective is to develop a preliminary method for rapid antibiotic susceptibility testing (RAST) in enterobacteria with inducible chromosomal AmpC. Methods: RAST was performed directly on spiked blood cultures of 49 enterobacteria with inducible chromosomal AmpC. Results were read at 4, 6 and 8h of incubation. Commercial broth microdilution was considered the reference method. Disks of 10 antibiotics were evaluated. Results: The proportion of readable tests at 4h was 85%. All RAST could be read at 6 and 8h. For most antibiotics, the S or R result at 4, 6 and 8h was greater than 80% after tentative breakpoints were established and Area of Technical Uncertainty was defined. Conclusions: This preliminary method seems to be of practical use, although it should be extended to adjust the breakpoints and differentiate them by species.(AU)

Introducción: El tratamiento precoz y adecuado de las bacteriemias disminuye la morbilidad y mortalidad de los pacientes. El objetivo es desarrollar un método preliminar de pruebas rápidas de sensibilidad antibiótica (PRSA) en enterobacterias con AmpC cromosómica inducible. Métodos: Las PRSA se realizaron directamente de hemocultivos simulados positivos para 49 enterobacterias con AmpC cromosómica inducible. Los resultados se leyeron a las 4, 6 y 8 horas de incubación. La microdilución en caldo comercial se consideró el método de referencia. Se evaluaron discos de 10 antibióticos. Resultados: La proporción de pruebas legibles a las 4 horas fue del 85%. Todas las PRSA pudieron leerse a las 6 y 8 horas. Para la mayoría de los antibióticos, el resultado S o R a las 4, 6 y 8 horas fue superior al 80%, después de que se establecieran puntos de corte provisionales y se definiera el área de incertidumbre técnica. Conclusiones: Este método preliminar parece ser de utilidad práctica, aunque debería ampliarse para ajustar los puntos de corte y diferenciar por especies.(AU)

Community Emergence of Cefixime-Resistant Escherichia coli Belonging to ST12 with Chromosomal AmpC Hyperproduction.

Escherichia coli isolates that are resistant to cefixime and amoxicillin/clavulanic acid, but apparently susceptible to cefuroxime, with no ESBL identified, were initially detected in Madrid from urine samples in 2019. Throughout 2020 and 2021, all cases of community UTI by E. coli from six health areas in Madrid were studied. A representative sample of 23 cases was selected for further studies. The broth microdilution method and the agar diffusion method were performed to determine the antibiotic susceptibility. WGS was carried out for phylogeny, resistome and virulome analysis. Community consumption of third-generation oral cephalosporins in Madrid (2017-2021) was analyzed. A total of 582 (1.3%) E. coli isolates had the mentioned resistance profile. The mutation at position -32 (T > A) of the AmpC promoter was found in 21 isolates. No plasmid AmpC- or ESBL-encoding genes were detected. A cluster of 20 ST12 isolates was detected by cgMLST. A 6.2% increase in the consumption of third-generation oral cephalosporins, especially cefixime, was observed in Madrid. Chromosomal AmpC-hyperproducing ST12 E. coli isolates could be implicated in the increase in community UTI cases by cefixime-resistant isolates, which correlates with an increasing trend of cefixime consumption.

Prevalence of fosA3 Gene in Fosfomycin-Resistant Proteus mirabilis in the Autonomous Community of Madrid (Spain) and Characterization of Two Positive Strains.

Plasmid-mediated resistance to fosfomycin has been seldom described in Proteus mirabilis. We report two strains harboring fosA3 gene. Whole-genome sequencing revealed a plasmid that encoded fosA3 gene flanked by two insertion sequence (IS)26 mobile elements. Both strains also produced the blaCTX-M-65 gene that was located in the same plasmid. The sequence detected was IS1182-blaCTX-M-65-orf1-orf2-IS26-IS26-fosA3-orf1-orf2-orf3-IS26. The importance of this transposon lies in its ability to spread in Enterobacterales, therefore, epidemiological surveillance should be carried out.

A Prospective Study of the Serological, Clinical, and Epidemiological Features of a SARS-CoV-2 Positive Pediatric Cohort.

Background: SARS-CoV-2 was a global pandemic. Children develop a mild disease and may have a different rate of seroconversion compared to adults. The objective was to determine the number of seronegative patients in a pediatric cohort. We also reviewed the clinical−epidemiological features associated with seroconversion. Methods: A multicenter prospective observational study during September−November 2020, of COVID-19, confirmed by reverse transcription-polymerase chain reaction. Data were obtained 4−8 weeks after diagnosis. Blood samples were collected to investigate the humoral response, using three different serological methods. Results: A total of 111 patients were included (98 symptomatic), 8 were admitted to hospital, none required an Intensive Care Unit visit. Median age: 88 months (IQR: 24−149). Median time between diagnosis and serological test: 37 days (IQR: 34−44). A total of 19 patients were non-seroconverters when using three serological techniques (17.1%; 95% CI: 10.6−25.4); most were aged 2−10 years (35%, p < 0.05). Univariate analysis yielded a lower rate of seroconversion when COVID-19 confirmation was not present amongst household contacts (51.7%; p < 0.05). Conclusions: There was a high proportion of non-seroconverters. This is more commonly encountered in childhood than in adults. Most seronegative patients were in the group aged 2−10 years, and when COVID-19 was not documented in household contacts. Most developed a mild disease. Frequently, children were not the index case within the family.

What's new in mechanisms of antibiotic resistance in bacteria of clinical origin?

The discovery, commercialization and administration of antibiotics revolutionized the world of medicine in the middle of the last century, generating a significant change in the therapeutic paradigm of the infectious diseases. Nevertheless, this great breakthrough was soon threatened due to the enormous adaptive ability that bacteria have, through which they are able to develop or acquire different mechanisms that allow them to survive the exposure to antibiotics. We are faced with a complex, multifactorial and inevitable but potentially manageable threat. To fight against it, a global and multidisciplinary approach is necessary, based on the support, guidance and training of the next generation of professionals. Nevertheless, the information published regarding the resistance mechanisms to antibiotics are abundant, varied and, unfortunately, not always well structured. The objective of this review is to structure the, in our opinion, most relevant and novel information regarding the mechanisms of resistance to antibiotics that has been published from January 2014 to September 2019, analysing their possible clinical and epidemiological impact.

What's new in mechanisms of antibiotic resistance in bacteria of clinical origin? / ¿Qué novedades hay en los mecanismos de resistencia a antimicrobianos en bacterias de origen clínico?

The discovery, commercialization and administration of antibiotics revolutionized the world of medicine in the middle of the last century, generating a significant change in the therapeutic paradigm of the infectious diseases. Nevertheless, this great breakthrough was soon threatened due to the enormous adaptive ability that bacteria have, through which they are able to develop or acquire different mechanisms that allow them to survive the exposure to antibiotics. We are faced with a complex, multifactorial and inevitable but potentially manageable threat. To fight against it, a global and multidisciplinary approach is necessary, based on the support, guidance and training of the next generation of professionals. Nevertheless, the information published regarding the resistance mechanisms to antibiotics are abundant, varied and, unfortunately, not always well structured. The objective of this review is to structure the, in our opinion, most relevant and novel information regarding the mechanisms of resistance to antibiotics that has been published from January 2014 to September 2019, analysing their possible clinical and epidemiological impact.(AU)

El descubrimiento, la comercialización y la administración de antibióticos revolucionó la medicina a mediados del siglo pasado, generando un cambio significativo en el paradigma terapéutico de las enfermedades infecciosas. Sin embargo, este avance no tardó en verse amenazado debido a la enorme capacidad que tienen las bacterias para desarrollar o adquirir distintos mecanismos que les permiten sobrevivir a los antibióticos. Nos encontramos frente a una amenaza compleja, multifactorial e inevitable, pero potencialmente manejable. Para luchar contra ella es necesario un abordaje multidisciplinar basado en el apoyo, la orientación y el entrenamiento de la próxima generación de profesionales. No obstante, la información publicada referente a nuevos mecanismos de resistencia a antibióticos es abundante, variada y, desgraciadamente, no siempre bien estructurada. El objetivo de esta revisión es ordenar la información, a nuestro juicio más relevante y novedosa, que se ha publicado en referencia los nuevos mecanismos de resistencia a los antibióticos desde enero de 2014 hasta septiembre de 2019, analizando su posible impacto clínico y epidemiológico.(AU)

Prevalence, detection and characterisation of fosfomycin-resistant Escherichia coli strains carrying fosA genes in Community of Madrid, Spain.

OBJECTIVES: The aim of this this study was to describe the presence of different variants of the fosA gene in fosfomycin-resistant Escherichia coli strains in Madrid, Spain. METHODS: fos genes were searched for in 55 E. coli strains collected from seven representative hospitals located in Madrid. A phenotypic screening test was performed following the disk diffusion method with sodium phosphonoformate added as described by Nakamura et al. Additionally, a molecular study based on PCR was used to confirm the screening results. Positive strains for fos genes were further subjected to whole-genome sequencing (WGS). RESULTS: Phenotypic screening was positive in 9/55 strains (16.4%), although genotypic detection was positive in only 3 (fosA3, fosA4 and fosA6). Thus, the prevalence of fos genes in Madrid was 5.5% (3/55). WGS data were not available for the fosA6-positive strain. One isolate with fosA3 (ST69) carried a blaCTX-M-55 gene and seven virulence genes (air, eilA, iha, iss, lpfA, sat and senB). The fosA4-positive isolate (ST4038) carried the virulence genes iss, lpfA, iroN and mchF. Both fos genes were located between two IS26 mobile elements of a plasmid. CONCLUSION: We detected the presence of different variants of plasmid-mediated fosA genes in fosfomycin-resistant E. coli strains in Madrid, Spain. Despite the few reports in Europe, it would be of interest to monitor the spread of these acquired resistance genes.

¿Es útil la estratificación de la sensibilidad antibiótica de los patógenos urinarios en el Servicio de Urgencias? / Is stratification of antibiotic susceptibility of urinary pathogens useful in the Emergency Department?

OBJETIVO: Determinar la sensibilidad antibiótica de los patógenos causantes de infección del tracto urinario (ITU) estratificándola en función de datos clínicos y demográficos de los pacientes. MATERIAL Y MÉTODOS: Se analizó sensibilidad antibiótica de las bacterias aisladas en orina de 144 pacientes con ITU escogidos al azar y se estratificó en función del sexo, la edad, el tipo de ITU, el haber padecido o no ITU previa y del tratamiento antibiótico previo. RESULTADOS: Se analizó la sensibilidad global de todas las cepas y de las cepas de E. coli observándose diferencias significativas en función del sexo (fluoroquinolonas), la edad (cefuroxima, ertapenem, gentamicina), el tipo de ITU (cefuroxima, cefotaxima, ertapenem, fluoroquinolonas), el haber tenido ITU previa y antibioterapia previa (cefotaxima, fluoroquinolonas, fosfomicina). CONCLUSIONES: El empleo de datos clínicos y demográficos adaptados a la población y a la epidemiología local de resistencia de los uropatógenos, podría ayudar a la elección del tratamiento empírico de la ITU

OBJECTIVE: The aim of the study wat to analyze the antibiotic susceptibility of the pathogens causing urinary tract infection (UTI) and to stratify the results in function of patient's clinical and demographic dates. MATERIAL AND METHODS: The susceptibility of the pathogens isolated in the urine of 144 patients with UTI randomly chosen was analyzed. The results were stratified in function of sex, age, type of UTI, previous UTI and previous antibiotic treatment. RESULTS: The susceptibility of the all isolates and of the Escherichia coli isolates was analyzed. There were significant differences between groups in function of sex (fluoroquinolones), age (cefuroxime, ertapenem and gentamicin), type of UTI (cefuroxime, cefotaxime, ertapenem and fluoroquinolones), previous UTI and previous antibiotic treatment (cefotaxime, fluoroquinolones and fosfomycin). CONCLUSIONS: The use of clinical and demographic data according to population and local resistance epidemiology of the pathogen causing UTI may help to select an adequate empirical treatment for UTI

Mechanisms of Linezolid Resistance Among Enterococci of Clinical Origin in Spain-Detection of optrA- and cfr(D)-Carrying E. faecalis.

The mechanisms of linezolid resistance among 13 E. faecalis and 6 E. faecium isolates, recovered from six Spanish hospitals during 2017-2018, were investigated. The presence of acquired linezolid resistance genes and mutations in 23S rDNA and in genes encoding for ribosomal proteins was analyzed by PCR and amplicon sequencing. Moreover, the susceptibility to 18 antimicrobial agents was investigated, and the respective molecular background was elucidated by PCR-amplicon sequencing and whole genome sequencing. The transferability of the linezolid resistance genes was evaluated by filter-mating experiments. The optrA gene was detected in all 13 E. faecalis isolates; and one optrA-positive isolate also carried the recently described cfr(D) gene. Moreover, one E. faecalis isolate displayed the nucleotide mutation G2576T in the 23S rDNA. This mutation was also present in all six E. faecium isolates. All linezolid-resistant enterococci showed a multiresistance phenotype and harbored several antimicrobial resistance genes, as well as many virulence determinants. The fexA gene was located upstream of the optrA gene in 12 of the E. faecalis isolates. Moreover, an erm(A)-like gene was located downstream of optrA in two isolates recovered from the same hospital. The optrA gene was transferable in all but one E. faecalis isolates, in all cases along with the fexA gene. The cfr(D) gene was not transferable. The presence of optrA and mutations in the 23S rDNA are the main mechanisms of linezolid resistance among E. faecalis and E. faecium, respectively. We report the first description of the cfr(D) gene in E. faecalis. The presence of the optrA and cfr(D) genes in Spanish hospitals is a public health concern.

Recommendations of the Spanish Antibiogram Committee (COESANT) for selecting antimicrobial agents and concentrations for in vitro susceptibility studies using automated systems / Recomendaciones del Comité Español del Antibiograma (COESANT) para la selección de antimicrobianos y sus concentraciones en el estudio in vitro de la sensibilidad con métodos automáticos

Automated antimicrobial susceptibility testing devices are widely implemented in clinical microbiology laboratories in Spain, mainly using EUCAST (European Committee on Antimicrobial Susceptibility Testing) breakpoints. In 2007, a group of experts published recommendations for including antimicrobial agents and selecting concentrations in these systems. Under the patronage of the Spanish Antibiogram Committee (Comité Español del Antibiograma, COESANT) and the Study Group on Mechanisms of Action and Resistance to Antimicrobial Agents (GEMARA) from the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), and aligned with the Spanish National Plan against Antimicrobial Resistance (PRAN), a group of experts have updated this document. The main modifications from the previous version comprise the inclusion of new antimicrobial agents, adaptation of the ranges of concentrations to cover the EUCAST breakpoints and epidemiological cut-off values (ECOFFs), and the inference of new resistance mechanisms. This proposal should be considered by different manufacturers and users when designing new panels or cards. In addition, recommendations for selective reporting are also included. With this approach, the implementation of EUCAST breakpoints will be easier, increasing the quality of antimicrobial susceptibility testing data and their microbiological interpretation. It will also benefit epidemiological surveillance studies as well as the clinical use of antimicrobials aligned with antimicrobial stewardship programs

Los sistemas automáticos utilizados en el estudio de la sensibilidad a los antimicrobianos están introducidos en la mayoría de los laboratorios de Microbiología Clínica en España, utilizando principalmente los puntos de corte del European Committee on Antimicrobial Susceptibility Testing (EUCAST). En 2007, un grupo de expertos publicó unas recomendaciones para incluir antimicrobianos y seleccionar concentraciones en estos sistemas. Bajo el auspicio del Comité Español del Antibiograma (COESANT) y del Grupo de Estudio de los Mecanismos de Acción y Resistencia a los Antimicrobianos (GEMARA) de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica (SEIMC) y alineado con el Plan Nacional frente a la Resistencia a los Antibióticos (PRAN), un grupo de expertos ha actualizado dicho documento. Las principales modificaciones realizadas sobre la versión anterior comprenden la inclusión de nuevos agentes antimicrobianos, la adaptación de los rangos de concentraciones para cubrir los puntos de corte clínicos y los puntos de corte epidemiológicos (ECOFF) definidos por el EUCAST, y para la inferencia de nuevos mecanismos de resistencia. Esta propuesta debería ser considerada por los diferentes fabricantes y los usuarios cuando se diseñen nuevos paneles o tarjetas. Además, se incluyen recomendaciones para realizar informes selectivos. Con este enfoque, la implementación de los puntos de corte del EUCAST será más fácil, aumentando la calidad de los datos del antibiograma y su interpretación microbiológica. También será de utilidad para los estudios de vigilancia epidemiológica, así como para el uso clínico de los antimicrobianos, de acuerdo con los programas de optimización de uso de antimicrobianos (PROA)

Escherichia coli resistant to fosfomycin from urinary tract infections: Detection of the fosA3 gene in Spain.

OBJECTIVES: The aim of this study was to report the epidemiological and genetic background of fosfomycin-resistant Escherichia coli isolates causing urinary tract infections (UTIs) in Spain. METHODS: A retrospective observational study of 39 randomly selected fosfomycin-resistant E. coli from urine samples collected during 2017 in Getafe (Spain) was performed. Medical records of 39 patients were reviewed. Phylogenetic groups were identified and the pandemic E. coli ST131 and clades thereof were sought by PCR and multilocus sequence typing (MLST). Screening and identification of fos genes and determination of their genetic environment (linkage to IS26) was performed by PCR. RESULTS: Of the 39 E. coli strains, 49% were ESBL-producers. Most of the strains belonged to phylogenetic group B2 (23/39; 59%), and all of these belonged to ST131 but to different clades (20 to clade C and 3 to clade B). Two isolates from phylogenetic group A (both ST10) carried a plasmid-borne fosA3 gene flanked by IS26. Of the 39 patients, 31 were female (mean age 78 years) and 8 were male (mean age 71 years). Moreover, 27 patients (69%) were diagnosed with complicated UTIs and the remaining 12 (31%) had uncomplicated UTIs, and 33 patients (85%) had been previously treated with fosfomycin. CONCLUSION: This study shows that fosfomycin-resistant E. coli strains are mainly isolated from elderly people with complicated UTIs and belong to the pandemic ST131 clone. To our knowledge, here we describe the fosA3 gene for the first time in Spain, which alerts for potential future dissemination that should be monitored.

Recommendations of the Spanish Antibiogram Committee (COESANT) for selecting antimicrobial agents and concentrations for in vitro susceptibility studies using automated systems.

Automated antimicrobial susceptibility testing devices are widely implemented in clinical microbiology laboratories in Spain, mainly using EUCAST (European Committee on Antimicrobial Susceptibility Testing) breakpoints. In 2007, a group of experts published recommendations for including antimicrobial agents and selecting concentrations in these systems. Under the patronage of the Spanish Antibiogram Committee (Comité Español del Antibiograma, COESANT) and the Study Group on Mechanisms of Action and Resistance to Antimicrobial Agents (GEMARA) from the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), and aligned with the Spanish National Plan against Antimicrobial Resistance (PRAN), a group of experts have updated this document. The main modifications from the previous version comprise the inclusion of new antimicrobial agents, adaptation of the ranges of concentrations to cover the EUCAST breakpoints and epidemiological cut-off values (ECOFFs), and the inference of new resistance mechanisms. This proposal should be considered by different manufacturers and users when designing new panels or cards. In addition, recommendations for selective reporting are also included. With this approach, the implementation of EUCAST breakpoints will be easier, increasing the quality of antimicrobial susceptibility testing data and their microbiological interpretation. It will also benefit epidemiological surveillance studies as well as the clinical use of antimicrobials aligned with antimicrobial stewardship programs.

ESBL-producing-multidrug resistant E. coli population from urinary tract infections is less diverse than non-ESBL-multidrug resistant population / La población de E. coli multirresistente productora de BLEE presente en infecciones del tracto urinario es menos diversa que la población multirresistente no productora de BLEE

OBJECTIVE: The aim of this study was to compare the population structure of three different representative groups of E. coli isolates causing urinary tract infections in a large area of Madrid, Spain: two groups of multidrug resistant isolates (MDR), ESBL- and non-ESBL producers, and one of fully-susceptible isolates (35 isolates in each group). METHODS: Epidemiological relatedness was studied by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The presence of genes encoding ESBL was determined by using PCR and sequencing. Antimicrobial susceptibility testing was performed by broth microdilution. RESULTS: PFGE analysis revealed a high degree of genetic diversity in susceptible and non-ESBL-MDR groups. However, the ESBL-MDR E. coli population was less diverse and a large cluster consisting of ST131 and CTX-M-15-producing isolates was detected. CONCLUSIONS: The present study revealed that ESBL-producing-MDR E. coli population was less diverse than the non-ESBL MDR group and that ST131 was dominant among CTX-M-15-producing isolates that reflects the spread of this successful MDR lineage

OBJETIVO: El objetivo del presente estudio fue comparar la estructura poblacional de tres grupos representativos diferentes de aislados de E. coli que producen infecciones del tracto urinario en una gran área de Madrid, España: dos grupos de aislados multirresistentes (multidrug resistant, MDR), productores y no productores de BLEE (β-lactamasas de espectro extendido), y uno de aislados totalmente sensibles (35 aislamientos en cada grupo). MÉTODOS: La relación epidemiológica se estudió mediante electroforesis en gel de campo pulsado (pulsed-field gel electrophoresis, PFGE) y tipificación de secuencias multilocus (multilocus sequence typing, MLST). La presencia de genes que codifican para BLEE se determinó mediante el uso de PCR y secuenciación. La prueba de sensibilidad a los antimicrobianos se realizó por microdilución del medio. RESULTADOS: El análisis de PFGE reveló un alto grado de diversidad genética en el grupo de sensibles y de MDR no productores de BLEE. Sin embargo, la población de E. coli MDR productora de BLEE era menos diversa y se detectó un grupo grande de aislados formado por productores de CTX-M-15 y ST131. CONCLUSIONES: El presente estudio reveló que la población de E. coli MDR productora de BLEE era menos diversa que el grupo MDR no productor de BLEE, y que ST131 era dominante en los aislados de productores de CTX-M-15, lo que refleja la propagación de esta exitosa línea de MDR

Is it possible to extrapolate the rates of resistance of Escherichia coli from asymptomatic bacteriuria in pregnant women to those of E. coli in uncomplicated community-acquired UTI? / ¿Es posible extrapolar las tasas de resistencia de Escherichia coli de bacteriurias asintomáticas en gestantes a las de E. coli en ITU no complicada adquirida en la comunidad?

OBJECTIVE: Treatment of uncomplicated urinary tract infections in primary care is generally empirical without requesting urine culture and based on biased resistance data collected from selected patients, most of them having risk factors for the isolation of resistant microorganisms. In order to overcome the lack of information on the real resistance rates in uncomplicated UTI, we compared antimicrobial phenotype and genotype of Escherichia coli isolated from pregnant women with asymptomatic bacteriuria (culture always performed) with those from women with uncomplicated acute cystitis (culture rarely performed) of different age groups. MATERIAL AND METHODS: Between September 2017 and March 2018, 103 urines were randomly collected from pregnant women aged between 16 and 47 with asymptomatic bacteriuria (AB) (n=42), not hospitalized women in the same age range with uncomplicated acute cystitis (UAC) (n=31) and women older than 47 not hospitalized with UAC (n=30). Bacteria identification was performed using mass spectrometry and the antibiogram by broth microdilution. Genetic typification was carried out by pulsed-field gel electrophoresis. RESULTS: There are no significant differences between the groups of patients in the antibiotic susceptibility. Likewise, as expected, a wide genetic diversity is observed among the strains of E. coli studied without significant differences between the three groups. CONCLUSIONS: We propose a simple model that could provide better guidance for selection of empirical antimicrobial therapy for non-pregnant women with UAC than do generic hospital antibiogram data based on reliably extrapolating the susceptibility data of strains isolated from pregnant women with AB as representation of women with community-acquired UAC

OBJETIVOS: El tratamiento en atención primaria de las infecciones del tracto urinario no complicadas es generalmente empírico sin solicitar urocultivo y basado en datos de resistencia sesgados procedentes de pacientes seleccionados, muchos de ellos con factores de riesgo de aislamiento de microorganismos resistentes. Con el fin de solventar el déficit de información sobre las tasas de resistencia reales en ITU no complicada, comparamos el fenotipo antimicrobiano y genotipo de aislados de Escherichia coli procedentes de mujeres embarazadas con bacteriuria asintomática (cultivo siempre realizado) con aquellos procedentes de mujeres con cistitis aguda no complicada (cultivo raramente realizado) de diferentes grupos de edad. MATERIAL Y MÉTODOS: Entre septiembre de 2017 y marzo de 2018 se recogieron aleatoriamente 103 orinas de mujeres embarazadas con edades entre 16 y 47 años con bacteriuria asintomática (BA) (n=42), mujeres no hospitalizadas en el mismo rango de edad con cistitis aguda no complicada (CANC) (n=31) y mujeres mayores de 47 años no hospitalizadas con CANC (n=30). La identificación bacteriana se realizó por espectrometría de masas y el antibiograma por microdilución en caldo. La tipificación genética se llevo a cabo por electroforesis en gel por campo pulsado. RESULTADOS: No hay diferencias significativas en la sensibilidad antibiótica entre los grupos de pacientes. De igual forma, y según lo esperado, se observó una amplia diversidad genética entre las cepas de E. coli estudiadas sin diferencias significativas entre los diferentes grupos. CONCLUSIONES: Proponemos un modelo sencillo que podría orientar mejor que los datos generales del hospital en la selección del tratamiento antimicrobiano empírico de mujeres no embarazadas con CANC, basado en extrapolar los datos de sensibilidad de cepas aisladas de mujeres embarazadas con BA como representación de mujeres con CANC adquirida en la comunidad

ESBL-producing-multidrug resistant E. coli population from urinary tract infections is less diverse than non-ESBL-multidrug resistant population.

OBJECTIVE: The aim of this study was to compare the population structure of three different representative groups of E. coli isolates causing urinary tract infections in a large area of Madrid, Spain: two groups of multidrug resistant isolates (MDR), ESBL- and non-ESBL producers, and one of fully-susceptible isolates (35 isolates in each group). METHODS: Epidemiological relatedness was studied by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The presence of genes encoding ESBL was determined by using PCR and sequencing. Antimicrobial susceptibility testing was performed by broth microdilution. RESULTS: PFGE analysis revealed a high degree of genetic diversity in susceptible and non-ESBL-MDR groups. However, the ESBL-MDR E. coli population was less diverse and a large cluster consisting of ST131 and CTX-M-15-producing isolates was detected. CONCLUSIONS: The present study revealed that ESBL-producing-MDR E. coli population was less diverse than the non-ESBL MDR group and that ST131 was dominant among CTX-M-15-producing isolates that reflects the spread of this successful MDR lineage.

Stratification by demographic and clinical data of the antibiotic susceptibility of Escherichia coli from urinary tract infections of the community.

AIM: To determine the patterns of antibiotic susceptibility of Escherichia coli strains isolated from adult patients with urinary tract infection (UTI), and to stratify the results by age and type of UTI to verify if there are statistically significant differences that can help physicians to prescribe better empirical antibiotherapy. DESIGN: Cross-sectional prospective study. LOCATION: Community of Getafe (Madrid). Primary care level. PARTICIPANTS: 100 E. coli strains, randomly chosen, isolated from the urine (104-105cfu/ml) of different patients from primary care centers in the Getafe area. MAIN MEASUREMENTS: The antibiotic susceptibility of the strains was evaluated and the results were stratified by age and type of UTI. The clinical and demographic data of the patients were analyzed, classifying each episode as complicated UTI or uncomplicated UTI. RESULTS: Strains isolated from patients with uncomplicated UTI showed significantly greater susceptibility than those of complicated UTI to amoxicillin (65.9% vs. 30.6%, p=0.001), amoxicillin/clavulanic acid (95.5% vs. 77.6%, p=0.013) and ciprofloxacin (81.8% vs. 63.3%, p=0.047). In complicated UTI, susceptibility to ciprofloxacin was significantly greater in the ≤65 years age group compared to the older age group (78.3% vs. 50%, respectively, p=0.041). In the rest of antibiotics, no statistically significant differences were obtained when comparing by age (≤65 years versus >65 years), both in uncomplicated and complicated UTI. CONCLUSIONS: Clinical and demographic data of patients with UTI are of great importance in the results of the antibiotic susceptibility in E. coli. Antibiograms stratified by patient characteristics may better facilitate empirical antibiotic selection for UTI in primary care.

Mycoplasma genitalium in Spain: prevalence of genital infection and frequency of resistance to macrolides / Mycoplasma genitalium en España: prevalencia de infección genital y frecuencia de resistencia a macrólidos

Introduction: The aim of this study was to determine the prevalence of Mycoplasma genitalium infection and the resistance to macrolides within a general population in Madrid in 2015. Methods: We collected 359 urine samples from a general population with symptoms of sexually transmitted infections (STIs). All samples underwent a real-time PCR. For the detection of macrolide resistance, a 283bp fragment of region V of the 23S rRNA gene of M. genitaliumwas amplified and sequenced. Results: We found a prevalence of 3.34% of M. genitalium and a macrolide resistance rate of 20%. In males, the prevalence was 6.62% and in women 0.96%, being significantly higher in males. Conclusions: The prevalence obtained shows that it is a pathogen to consider in our environment. These findings stress the need for routine testing of M. genitalium infections and would seem to suggest the advisability of resistance testing (AU)

Introducción: El objetivo de este estudio fue determinar en 2015 en una población general de Madrid la prevalencia de infección por Mycoplasma genitalium (M. genitalium) y la resistencia a macrólidos. Métodos: Se recogieron 359 muestras de orina procedentes de una población general con síntomas de infección de transmisión sexual. A todas las muestras se les realizó una PCR a tiempo real. Para la detección de resistencias a macrólidos, se amplificó y secuenció un fragmento de 283 pb de la región V del gen 23S rRNA de M. genitalium. Resultados: Se encontró una prevalencia de un 3,34% de M. genitalium y un 20% de resistencia a macrólidos. En varones la prevalencia fue del 6,62% y en mujeres del 0,96%, siendo significativamente superior en varones. Conclusión: La prevalencia obtenida muestra que es un patógeno a considerar en nuestro entorno. Estos hallazgos hacen hincapié en la necesidad de realizar pruebas de rutina de infección por M. genitalium y argumentan que es recomendable realizar pruebas de resistencia (AU)