Within-host transition to GES-55 during a GES-6-producing Serratia marcescens outbreak: Emergence of ceftazidime-avibactam resistance and increased susceptibility to carbapenems.

OBJECTIVES: To describe the in vivo emergence of ceftazidime-avibactam resistance in GES-type carbapenemases and to characterize an unusual outbreak of GES-6-producing Serratia marcescens during the COVID-19 pandemic in Spain. METHODS: Retrospective study to describe a GES-CPSM outbreak based on whole genome sequencing and antimicrobial susceptibility testing (AST). Transferability of blaGES-carrying plasmid was assessed by conjugation experiments. RESULTS: In December 2020, we identified a cluster of S. marcescens harbouring blaGES-6 involving 9 patients. Whole-genome sequence analysis revealed a clonal relationship (≤3 SNPs) between the first isolates identified in each of the evolved patients and environmental samples with GES-CPSM detection. Plasmid analysis showed that the blaGES-6 gene was located in an IncQ3-type plasmid. Triparental mating experiments using a helper plasmid demonstrated mobilization of the blaGES-6-carrying plasmid. Our results also demonstrate within-host evolution in S. marcescens isolates, leading to a transition from blaGES-6 to the new blaGES-55, caused by the P162S mutation, in a subsequent infection in one of the affected patients. In blaGES-55 we identified emergence of ceftazidime-avibactam resistance along with an increase of carbapenems susceptibility. This patient had been treated with a 14-day course of ceftazidime-avibactam. AST of the transformants bearing blaGES-6 and blaGES-55 plasmids, confirmed susceptibility variation affecting ceftazidime-avibactam and carbapenems. CONCLUSIONS: We report an unusual outbreak of GES-6 whose incidence is becoming increasing. Transition from GES-6 to GES-55 may readily occur in vivo leading to ceftazidime-avibactam resistance, which brings to the fore the critical need for developing more accurate diagnosis tools for detection of GES ß-lactamases and optimise the use of antimicrobials.

In Vitro Activity of Cefepime-Taniborbactam against Carbapenemase-Producing Enterobacterales and Pseudomonas aeruginosa Isolates Recovered in Spain.

Novel ß-lactam-ß-lactamase inhibitor combinations currently approved for clinical use are poorly active against metallo-ß-lactamase (MBL)-producing strains. We evaluated the in vitro activity of cefepime-taniborbactam (FTB [formerly cefepime-VNRX-5133]) and comparator agents against carbapenemase-producing Enterobacterales (n = 247) and carbapenem-resistant Pseudomonas species (n = 170) clinical isolates prospectively collected from different clinical origins in patients admitted to 8 Spanish hospitals. FTB was the most active agent in both Enterobacterales (97.6% MICFTB, ≤8/4 mg/L) and Pseudomonas (67.1% MICFTB, ≤8/4 mg/L) populations. The MICFTB was >8 mg/L in 6/247 (2.4%) Enterobacterales isolates (3 KPC-producing Klebsiella pneumoniae isolates, 1 VIM-producing Enterobacter cloacae isolate, 1 IMP-producing E. cloacae isolate, and 1 NDM-producing Escherichia coli isolate) and in 56/170 (32.9%) Pseudomonas isolates, 19 of them carbapenemase producers (15 producers of VIM, 2 of GES, 1 of GES+VIM, and 1 of GES+KPC). Against the Enterobacterales isolates with meropenem MICs of >2 mg/L (138/247), FTB was the most active agent against both serine-ß-lactamases (107/138) and MBL producers (31/138) (97.2 and 93.5% MICFTB, ≤8/4 mg/L, respectively), whereas the activity of comparators was reduced, particularly against the MBL producers (ceftazidime-avibactam, 94.4 and 12.9%, meropenem-vaborbactam, 85.0 and 64.5%, imipenem-relebactam, 76.6 and 9.7%, ceftolozane-tazobactam, 1.9 and 0%, and piperacillin-tazobactam, 0 and 0%, respectively). Among the meropenem-resistant Pseudomonas isolates (163/170; MIC, >2 mg/L), the activities of FTB against serine-ß-lactamase (35/163) and MBL (43/163) producers were 88.6 and 65.1%, respectively, whereas the susceptibilities of comparators were as follows: ceftazidime-avibactam, 88.5 and 16.0%, meropenem-vaborbactam, 8.5 and 7.0%, imipenem-relebactam, 2.9 and 2.3%, ceftolozane-tazobactam, 0 and 2.3%, and piperacillin-tazobactam, 0 and 0%, respectively. Microbiological results suggest FTB as a potential therapeutic option in patients infected with carbapenemase-producing Enterobacterales and carbapenem-resistant Pseudomonas isolates, including MBL producers.

Primer caso descrito en España de infección por Wohlfahrtiimonas chitiniclastica / First case of infection by Wohlfahrtiimonas chitiniclastica described in Spain

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Mechanisms of resistance to daptomycin in Staphylococcus aureus / Mecanismos de resistencia a daptomicina en Staphylococcus aureus

Daptomycin is a cyclic lipopeptide active against multidrug-resistant Gram-positives, including methicillinresistant Staphylococcus aureus (MRSA) and S. aureus with reduced susceptibility to vancomycin. It is 4-8 fold as active as vancomycin against methicillin-susceptible S. aureus (MSSA) and MRSA, and retains most of this activity against S. aureus with reduced susceptibility to vancomycin. The mechanism of action of daptomycin is not fully understood. Daptomycin binds to the bacterial cytoplasmic membrane, leading to depolarization due to the loss of potassium ions from the cytoplasm. Daptomycin non-susceptibility is unusual in the clinical setting. Different mechanisms have been proposed to explain daptomycin-resistance, most of them associated to changes in composition, charge and fluidity of the cell wall. The mprF mutations, which lead to an increase in the lysyl-phosphatidyl glycerol production, and rpoB and rpoC mutations (rpo genes encode for bacterial RNA polymerase subunits) have been proposed as associated to daptomycinresistance, but a number of mutations in other genes ( walK, cls, ggrA…) have been proposed (AU)

Daptomicina es un lipopéptido cíclico, activo frente a microorganismos grampositivos multirresistentes, incluyendo Staphylococcus aureus resistente a meticilina (SARM) y S. aureus con sensibilidad reducida a vancomicina. Es 4-8 veces más activa que vancomicina frente a S. aureus sensible a meticilina (SASM) y SARM, y mantiene prácticamente la misma actividad frente a S. aureus con sensibilidad reducida a vancomicina. El mecanismo de acción de daptomicina no está completamente explicado. Daptomicina se une a la membrana citoplasmática bacteriana y da lugar a su despolarización, como consecuencia de la pérdida de iones potasio. La resistencia a daptomicina es todavía infrecuente en el ámbito clínico. Se han propuesto diversos mecanismos de resistencia, en su mayor parte asociados a cambios en la composición, carga y fluidez de la membrana celular. Se ha propuesto la asociación de la resistencia a daptomicina con mutaciones en los genes mprF, que dan lugar a un aumento en la producción de lisil-fosfatidil-glicerol, a mutaciones en rpoB y rpoC (los genes rpo codifican diferentes subunidades de la ARN polimerasa bacteriana) pero también a mutaciones en otro numeroso grupo de genes (walK, cls, ggrA, etc.) (AU)

Parásitos e inmigración: ¿cuál es la mejor actitud? / Parasites and immigration: what is the best approach?

El aumento de la población inmigrante en Europa (en España se considera que supone, en este momento, el 10% de la población total) conlleva un incremento en la prevalencia de determinadas enfermedades, en especial enfermedades infecciosas, y obliga a enfocar el estudio de los pacientes teniendo muy en cuenta las enfermedades prevalentes en su zona de origen. Diferentes organismos defienden el cribado sistemático, o el tratamiento empírico indiscriminado. El cribado debe incluir, al menos, un estudio coproparasitológico, de hemoparásitos y de parásitos urinarios. El estudio coproparasitológico es esencial, dada la alta prevalencia de parásitos intestinales en población procedente de áreas tropicales y subtropicales. La búsqueda de hemoparásitos es fundamental para la detección de Plasmodium, Babesia, Trypanosoma y también de algunas filarias. En individuos asintomáticos procedentes de zonas endémicas para Plasmodium es primordial la introducción de técnicas moleculares, dada la baja sensibilidad del resto. Todo individuo procedente de áreas endémicas para filariasis o enfermedad de Chagas debe ser sometido al cribado de estas. El cribado de Trypanosoma cruzi es de especial relevancia en embarazadas y donantes de sangre y de órganos. Se revisan los agentes etiológicos a tener en cuenta en población inmigrante ante un síndrome febril, cardiovascular, respiratorio, digestivo, hepatoesplenomegalia, síndromes nefrourológicos, neurológicos, reumatológicos, oftalmológicos, otorrinolaringológicos y cutáneos (AU)

The increasing immigrant population in Europe (in Spain it is assumed to account for 10% of the total population) is leading to a higher prevalence of some diseases, especially infectious diseases. When studying these patients, the most prevalent diseases in their area of origin must be taken into account. Different agencies advocate systematic screening, or indiscriminate empirical treatment. Screening should include a search for parasites in stool, blood and urine samples. Stool parasitological studies are fundamental, given the high prevalence of intestinal parasites in populations from tropical and subtropical areas. The search for blood parasites is essential for the detection of Plasmodium, Babesia, Trypanosoma and also some filaria. In asymptomatic individuals coming from areas endemic for Plasmodium, the use of molecular techniques is necessary, given the low sensitivity of conventional methods. All individuals from areas endemic for filariasis or Chagas disease should be screened. Screening for Trypanosoma cruzi is particularly important in pregnant women and blood and organ donors. We review the main agents to be considered in immigrant patients showing febrile, cardiovascular, respiratory or gastrointestinal syndromes, hepatosplenomegaly, and nephro-urological, neurological, rheumatologic, ophthalmological, ear, nose and throat (ENT) and cutaneous síndromes (AU)

The Pitt Bacteremia Score, Charlson Comorbidity Index and Chronic Disease Score are useful tools for the prediction of mortality in patients with Candida bloodstream infection.

Candida bloodstream infection (CBI) is associated with high mortality. The aim of this study was to compare the utility of the combined use of the Pitt Bacteremia Score (PBS) and Charlson Comorbidity Index (CCI) or Chronic Disease Score (CDS) to predict mortality among patients with CBI. Thereby, all consecutive patients with CBI at our institution between 2010 and 2014 were included. The PBS was used to evaluate CBI severity and the CCI and CDS were used to assess comorbidities of patients with CBI. Logistic regression analysis was used to estimate odds ratios for 30-day mortality in models including the PBS and CCI or CDS. A total of 189 CBI episodes were identified. Logistic regression models including the PBS and either CCI or CDS showed that the combined use of a comorbidity score and a severity score significantly predicted 30-day mortality. The performance of the different models was similar. Aggregated scores of comorbidity (CCI and CDS) and disease severity (PBS) are useful for the prediction of 30-day mortality risk in patients with CBI. Their use may facilitate the analysis of risk factors for poorer outcome and the development of an index for CBI mortality.

Métodos rápidos de identificación de bacterias y hongos. Espectrometría de masas MALDI-TOF, medios cromogénicos / Fast methods of fungal and bacterial identification. MALDI-TOF mass spectrometry, chromogenic media

La espectrometría de masas MALDI-TOF es ya una herramienta de trabajo rutinaria en Microbiología Clínica, por su rapidez y fiabilidad en la identificación de microorganismos. Sus resultados están perfectamente contrastados en la identificación de bacterias y levaduras. La identificación de micobacterias y hongos filamentosos presenta mayor complejidad, por la mayor heterogeneidad de espectros dentro de cada especie. La metodología es algo más compleja, y la ampliación del número de especies de referencia, y del número de espectros de cada especie, serán cruciales para alcanzar mayor eficacia. La identificación directa a partir de hemocultivos se ha implantado dada su aportación al manejo de pacientes graves, pero su aplicación a otras muestras es más compleja. Los medios de cultivos cromogénicos han supuesto también una aportación al diagnóstico rápido tanto en bacterias como en levaduras, ya que aceleran el diagnóstico, facilitan la detección de cultivos mixtos y permiten un diagnóstico rápido de especies resistentes

MALDI-TOF mass spectrometry is now a routine resource in Clinical Microbiology, because of its speed and reliability in the identification of microorganisms. Its performance in the identification of bacteria and yeasts is perfectly contrasted. The identification of mycobacteria and moulds is more complex, due to the heterogeneity of spectra within each species. The methodology is somewhat more complex, and expanding the size of species libraries, and the number of spectra of each species, will be crucial to achieve greater efficiency. Direct identification from blood cultures has been implemented, since its contribution to the management of severe patients is evident, but its application to other samples is more complex. Chromogenic media have also contributed to the rapid diagnosis in both bacteria and yeast, since they accelerate the diagnosis, facilitate the detection of mixed cultures and allow rapid diagnosis of resistant species

Unusual clinical presentations of Actinotignum (Actinobaculum) schaalii infection / Presentaciones clínicas inusuales de la infección por Actinotignum (Actinobaculum) schaalii

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Fast methods of fungal and bacterial identification. MALDI-TOF mass spectrometry, chromogenic media. / Métodos rápidos de identificación de bacterias y hongos. Espectrometría de masas MALDI-TOF, medios cromogénicos.

MALDI-TOF mass spectrometry is now a routine resource in Clinical Microbiology, because of its speed and reliability in the identification of microorganisms. Its performance in the identification of bacteria and yeasts is perfectly contrasted. The identification of mycobacteria and moulds is more complex, due to the heterogeneity of spectra within each species. The methodology is somewhat more complex, and expanding the size of species libraries, and the number of spectra of each species, will be crucial to achieve greater efficiency. Direct identification from blood cultures has been implemented, since its contribution to the management of severe patients is evident, but its application to other samples is more complex. Chromogenic media have also contributed to the rapid diagnosis in both bacteria and yeast, since they accelerate the diagnosis, facilitate the detection of mixed cultures and allow rapid diagnosis of resistant species.

Screening for parasite infections in immigrant children from low-income countries / Detección de infecciones parasitarias en menores inmigrantes procedentes de países en vías de desarrollo

INTRODUCTION: In Spain, minors represent approximately 20% of the immigration flow. Many of these immigrants come from countries in the tropics and sub-tropics where intestinal parasitic infections caused by helminths and protozoa are one of the major causes of human disease. The main objective of the present work was to describe parasite infections in a group of immigrant children. METHODS: A prospective evaluation was performed in 373 minors from Sub-Saharan Africa, North Africa, and Latin America. Details were collected from the medical records and physical examination. Urine, stool and peripheral blood samples were obtained for serological and routine laboratory tests. Direct and indirect parasitological tests were also performed. RESULTS: At least 1 parasitic disease was diagnosed in 176 (47.1%) immigrant children, while 77 (20.6%) minors were infected with two or more parasites. The number of parasites was highest in children from Sub-Saharan Africa compared with the rest of the areas of origin (p<.001), and in children from urban areas compared with those from rural areas (OR 1.27 [1.059-1.552], p=.011). The most frequent causes of multiple parasite infection were filariasis plus strongyloidiasis and filariasis plus schistosomiasis. Intestinal parasite infection was diagnosed in 38 cases (13.8%). Logistic regression analysis revealed that for each month of stay, the probability of a positive finding in the stool sample decreased by 0.02% [β=−0.020, (p=.07)]. CONCLUSIONS: The high infection rates of parasite diseases in immigrant children point to the need for screening protocols for certain infectious diseases in these children according to their country of origin and their length of residence in Spain

INTRODUCCIÓN: En España, los menores representan aproximadamente el 20% del flujo migratorio. Muchos de estos menores provienen de regiones tropicales y subtropicales donde las infecciones por helmintos y protozoos son una de las principales causas de morbilidad. El objetivo de este trabajo es describir las infecciones parasitarias presentes en un colectivo de menores inmigrantes. MÉTODOS: Se evaluaron prospectivamente 373 menores procedentes de África subsahariana, África del Norte y Latinoamérica. Se realizó una historia clínica detallada. Se obtuvieron muestras de sangre periférica, orina y heces para la realización de los diferentes análisis bioquímicos, serológicos y parasitológicos directos e indirectos. RESULTADOS: En 176 (47,1%) menores se diagnosticó al menos una enfermedad parasitaria. En 77 (20,6%) menores se detectaron 2 o más parásitos. En los niños de África subsahariana el número de parásitos fue mayor comparado el resto de orígenes (p < 0,001). Los menores de zonas urbanas tenían más parásitos comparado con los niños de zonas rurales (OR 1,27 [1059-1552], p = 0,011). Las causas más frecuentes de parasitación múltiple fueron filariosis más estrongiloidosis y filariosis más esquistosomiasis. Se diagnosticó parasitosis intestinal en 38 casos (13,8%). El análisis de regresión logística reveló que por cada mes de estancia, la probabilidad de un resultado positivo en las heces disminuía un 0,02% [β=−0,020 (p = 0,07)]. CONCLUSIÓN: Las altas tasas de infección parasitaria en niños inmigrantes señala la necesidad de una detección protocolizada de estas enfermedades según el país de origen y el tiempo de residencia en España

Screening for parasite infections in immigrant children from low-income countries.

INTRODUCTION: In Spain, minors represent approximately 20% of the immigration flow. Many of these immigrants come from countries in the tropics and sub-tropics where intestinal parasitic infections caused by helminths and protozoa are one of the major causes of human disease. The main objective of the present work was to describe parasite infections in a group of immigrant children. METHODS: A prospective evaluation was performed in 373 minors from Sub-Saharan Africa, North Africa, and Latin America. Details were collected from the medical records and physical examination. Urine, stool and peripheral blood samples were obtained for serological and routine laboratory tests. Direct and indirect parasitological tests were also performed. RESULTS: At least 1 parasitic disease was diagnosed in 176 (47.1%) immigrant children, while 77 (20.6%) minors were infected with two or more parasites. The number of parasites was highest in children from Sub-Saharan Africa compared with the rest of the areas of origin (p<.001), and in children from urban areas compared with those from rural areas (OR 1.27 [1.059-1.552], p=.011). The most frequent causes of multiple parasite infection were filariasis plus strongyloidiasis and filariasis plus schistosomiasis. Intestinal parasite infection was diagnosed in 38 cases (13.8%). Logistic regression analysis revealed that for each month of stay, the probability of a positive finding in the stool sample decreased by 0.02% [ß=-0.020, (p=.07)]. CONCLUSIONS: The high infection rates of parasite diseases in immigrant children point to the need for screening protocols for certain infectious diseases in these children according to their country of origin and their length of residence in Spain.

Pápula supraciliar derecha única en paciente con leucemia linfática crónica: importancia del diagnóstico precoz / Solitary papule above the right eyebrow in patient with chronic lymphocytic leukemia: Importance of early diagnosis

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[Epidemiology of Clostridium difficile-associated disease (CDAD) in Salamanca]. / Epidemiología de la Enfermedad Asociada a Clostridium difficile (EACD) en Salamanca.

INTRODUCTION: Clostridium difficile infection is considered a major cause of nosocomial diarrhoea in developed countries and is increasingly becoming more important as an etiologic agent of community diarrhoea, also in patients without risk factors. METHOD: Beginning in May 2011, the aim of our study is to know the characteristics of patients suffering from C. difficile Associated Disease in Salamanca University Hospital, collecting their data in a survey conducted for this purpose. A case was defined as a patient with compatible clinical and positive microbiological diagnosis. RESULTS: After 18 months of study, 41 cases had been documented representing an incidence of 1.15 cases per 10,000 patient-days. Patients were hospitalized (37) or health care associated (4), females (54%), age ≥ 65 years (56%) with prior antibiotic treatment (80%), most had diarrhea after the third day of admission, less than three weeks and without blood. Most were treated with metronidazole alone (78%), 19% with metronidazole and vancomycin, and the remaining percentage was resolved without treatment. Recurrences were about 20% and 7 (17%) died. CONCLUSIONS: The characteristics of our patients with C. difficile - associated disease are the same as those reported by other authors. Local surveillance is important in order to study the endemic and epidemic C. difficile infection. According to published epidemiological changes, we should be able to develop strategies from the Microbiology laboratories that will improve diagnosis of the disease.

Epidemiología de la Enfermedad Asociada a Clostridium difficile (EACD) en Salamanca / Epidemiology of Clostridium difficile-associated disease (CDAD) in Salamanca

Introducción. La infección por Clostridium difficile se considera la principal causa de diarrea nosocomial en países desarrollados y cada vez cobra más relevancia como agente etiológico de diarreas comunitarias, y en pacientes sin factores considerados de riesgo. Método. En este estudio que comienza en Mayo de 2011 planteamos conocer las características de los pacientes afectados de Enfermedad Asociada a C. difficile en el Complejo Asistencial Universitario de Salamanca, recogiendo sus datos en una encuesta elaborada a tal efecto. Se consideró como caso el paciente con clínica compatible y diagnóstico microbiológico positivo. Resultados. A los 18 meses del comienzo se habían documentado 41 casos lo que supone una incidencia de 1.15 casos por 10.000 pacientes-día. Fueron pacientes hospitalizados (37) o relacionados con asistencia sanitaria (4), mujeres (54%), añosas (56%) con tratamiento antibiótico previo (80%), la mayoría presentaron diarrea tras el tercer día de ingreso, de menos de tres semanas y sin sangre. La mayoría fueron tratados solo con metronidazol (78%), un 19% con metronidazol y vancomicina asociados y el restante se resolvió sin tratamiento. Recayeron cerca de un 20% y 7 (17%) fallecieron. Conclusiones. Las características de nuestros pacientes con Enfermedad Asociada a C. difficile son las mismas que reportan otros autores. Es importante la vigilancia local para conocer la endemia y vigilar las modificaciones no esperables de la incidencia. Teniendo en cuenta los cambios epidemiológicos que reporta la bibliografía, desde Microbiología debemos trabajar en estrategias que optimicen el diagnóstico de esta enfermedad (AU)

Introduction. Clostridium difficile infection is considered a major cause of nosocomial diarrhoea in developed countries and is increasingly becoming more important as an etiologic agent of community diarrhoea, also in patients without risk factors. Method. Beginning in May 2011, the aim of our study is to know the characteristics of patients suffering from C. difficile Associated Disease in Salamanca University Hospital, collecting their data in a survey conducted for this purpose. A case was defined as a patient with compatible clinical and positive microbiological diagnosis. Results. After 18 months of study, 41 cases had been documented representing an incidence of 1.15 cases per 10,000 patient-days. Patients were hospitalized (37) or health care associated (4), females (54%), age ≥65 years (56%) with prior antibiotic treatment (80%), most had diarrhea after the third day of admission, less than three weeks and without blood. Most were treated with metronidazole alone (78%), 19% with metronidazole and vancomycin, and the remaining percentage was resolved without treatment. Recurrences were about 20% and 7 (17%) died. Conclusions. The characteristics of our patients with C. difficile - associated disease are the same as those reported by other authors. Local surveillance is important in order to study the endemic and epidemic C. difficile infection. According to published epidemiological changes, we sould be able to develop strategies from the Microbiology laboratories that will improve diagnosis of the disease (AU)