Differential effects of the second SARS-CoV-2 mRNA vaccine dose on T cell immunity in naive and COVID-19 recovered individuals.

The rapid development of mRNA-based vaccines against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the design of accelerated vaccination schedules that have been extremely effective in naive individuals. While a two-dose immunization regimen with the BNT162b2 vaccine has been demonstrated to provide a 95% efficacy in naive individuals, the effects of the second vaccine dose in individuals who have previously recovered from natural SARS-CoV-2 infection has not been investigated in detail. In this study, we characterize SARS-CoV-2 spike-specific humoral and cellular immunity in naive and previously infected individuals during and after two doses of BNT162b2 vaccination. Our results demonstrate that, while the second dose increases both the humoral and cellular immunity in naive individuals, COVID-19 recovered individuals reach their peak of immunity after the first dose. These results suggests that a second dose, according to the current standard regimen of vaccination, may be not necessary in individuals previously infected with SARS-CoV-2.

Enhanced Antibacterial Activity of Repurposed Mitomycin C and Imipenem in Combination with the Lytic Phage vB_KpnM-VAC13 against Clinical Isolates of Klebsiella pneumoniae.

Klebsiella pneumoniae is an opportunistic Gram-negative pathogen that employs different strategies (resistance and persistence) to counteract antibiotic treatments. This study aimed to search for new means of combatting imipenem-resistant and persister strains of K. pneumoniae by repurposing the anticancer drug mitomycin C as an antimicrobial agent and by combining the drug and the conventional antibiotic imipenem with the lytic phage vB_KpnM-VAC13. Several clinical K. pneumoniae isolates were characterized, and an imipenem-resistant isolate (harboring OXA-245 ß-lactamase) and a persister isolate were selected for study. The mitomycin C and imipenem MICs for both isolates were determined by the broth microdilution method. Time-kill curve data were obtained by optical density at 600 nm (OD600) measurement and CFU enumeration in the presence of each drug alone and with the phage. The frequency of occurrence of mutants resistant to each drug and the combinations was also calculated, and the efficacy of the combination treatments was evaluated using an in vivo infection model (Galleria mellonella). The lytic phage vB_KpnM-VAC13 and mitomycin C had synergistic effects on imipenem-resistant and persister isolates, both in vitro and in vivo. The phage-imipenem combination successfully killed the persisters but not the imipenem-resistant isolate harboring OXA-245 ß-lactamase. Interestingly, the combinations decreased the emergence of in vitro resistant mutants of both isolates. Combinations of the lytic phage vB_KpnM-VAC13 with mitomycin C and imipenem were effective against the persister K. pneumoniae isolate. The lytic phage-mitomycin C combination was also effective against imipenem-resistant K. pneumoniae strains harboring OXA-245 ß-lactamase.

Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study.

BACKGROUND: Spain is one of the European countries most affected by the COVID-19 pandemic. Serological surveys are a valuable tool to assess the extent of the epidemic, given the existence of asymptomatic cases and little access to diagnostic tests. This nationwide population-based study aims to estimate the seroprevalence of SARS-CoV-2 infection in Spain at national and regional level. METHODS: 35 883 households were selected from municipal rolls using two-stage random sampling stratified by province and municipality size, with all residents invited to participate. From April 27 to May 11, 2020, 61 075 participants (75·1% of all contacted individuals within selected households) answered a questionnaire on history of symptoms compatible with COVID-19 and risk factors, received a point-of-care antibody test, and, if agreed, donated a blood sample for additional testing with a chemiluminescent microparticle immunoassay. Prevalences of IgG antibodies were adjusted using sampling weights and post-stratification to allow for differences in non-response rates based on age group, sex, and census-tract income. Using results for both tests, we calculated a seroprevalence range maximising either specificity (positive for both tests) or sensitivity (positive for either test). FINDINGS: Seroprevalence was 5·0% (95% CI 4·7-5·4) by the point-of-care test and 4·6% (4·3-5·0) by immunoassay, with a specificity-sensitivity range of 3·7% (3·3-4·0; both tests positive) to 6·2% (5·8-6·6; either test positive), with no differences by sex and lower seroprevalence in children younger than 10 years (<3·1% by the point-of-care test). There was substantial geographical variability, with higher prevalence around Madrid (>10%) and lower in coastal areas (<3%). Seroprevalence among 195 participants with positive PCR more than 14 days before the study visit ranged from 87·6% (81·1-92·1; both tests positive) to 91·8% (86·3-95·3; either test positive). In 7273 individuals with anosmia or at least three symptoms, seroprevalence ranged from 15·3% (13·8-16·8) to 19·3% (17·7-21·0). Around a third of seropositive participants were asymptomatic, ranging from 21·9% (19·1-24·9) to 35·8% (33·1-38·5). Only 19·5% (16·3-23·2) of symptomatic participants who were seropositive by both the point-of-care test and immunoassay reported a previous PCR test. INTERPRETATION: The majority of the Spanish population is seronegative to SARS-CoV-2 infection, even in hotspot areas. Most PCR-confirmed cases have detectable antibodies, but a substantial proportion of people with symptoms compatible with COVID-19 did not have a PCR test and at least a third of infections determined by serology were asymptomatic. These results emphasise the need for maintaining public health measures to avoid a new epidemic wave. FUNDING: Spanish Ministry of Health, Institute of Health Carlos III, and Spanish National Health System.

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)

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.

A cluster of Chryseobacterium indologenes cases related to drainage water in intensive care units.

In this outbreak, 12 patients in intensive care units acquired a Chryseobacterium indologenes infection. Cultures from sinkholes and air samples were positive for C. indologenes. After removing wash basins, no new cases appeared. Sinkholes, potentially contaminated, can act as a reservoir for C. indologenes and other microorganisms. Thus, patients and equipment should be protected from sink splashes to avoid contamination.

Colonization with Enterobacteriaceae-Producing ESBLs, AmpCs, and OXA-48 in Wild Avian Species, Spain 2015-2016.

Antibiotic resistance is a global threat of complex and changeable epidemiology. The role of wild birds in the dissemination of antibacterial resistance might be underestimated. We studied the cloacal colonization by cefotaxime-resistant Enterobacteriaceae in 668 wild birds in Spain. Eighty-eight wild birds (13.2%) of 28 species carried cefotaxime-resistant isolates; 58 of them (8.7%) carried extended-spectrum ß-lactamases (ESBLs) and 15 (2.5%) plasmid-mediated AmpCs of the blaCIT family. The 58 ESBLs belonged to the CTX-M-1 group (63.9%), CTX-M-9 group (23%), and SHV-group (13.1%). Pulsed field gel electrophoresis (PFGE) analysis of the Escherichia coli isolates revealed a high degree of genetic diversity since 44 different PFGE patterns were observed among the 54 cefotaxime-resistant isolates analyzed. Two clusters were detected with a genetic linkage >90%: Cluster 1 included nine CTX-M-15-producing isolates of ST23, and Cluster 2 included four isolates producing plasmid mediated AmpC of the CIT family of ST744. In addition, five birds were colonized by OXA-48- and CTX-M-15-producing isolates: three Klebsiella pneumoniae (isolated from Eurasian eagle-owl, lesser kestrel, and common buzzard), one E. coli (common buzzard), and one Enterobacter cloacae (cattle egret). Also, an mcr-1-positive and CIT-producing E. coli isolate colonized a black vulture. By multilocus sequence typing, the three OXA-48-producing K. pneumoniae isolates belonged to the high-risk human clones ST11 (two) and ST15 (one); the OXA-48-producing E. coli belonged to ST23, and the mcr-1-positive E. coli belonged to ST162. The diversity of eating patterns and migratory habits of the multiple avian species, capable of carrying multiresistant bacteria as observed in this study, may contribute to their global dissemination from human sources.

Brote por Enterococcus faecium ST17 resistente a glucopéptidos en una Unidad de Neonatología / Vancomycin-resistant Enterococcus faecium ST17 outbreak in a Neonatal Unit

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Métodos microbiológicos para la vigilancia del estado de portador de bacterias multirresistentes / Microbiological methods for surveillance of carrier status of multiresistant bacteria

La existencia de pacientes colonizados es una de las principales vías de propagación de las bacterias multirresistentes, y su contención una prioridad asistencial y de salud pública. Los estudios de vigilancia son imprescindibles para una detección precoz de la colonización por estas bacterias. Este artículo aborda los diferentes métodos microbiológicos, basados en el cultivo y moleculares, para la detección del estado de portador de bacterias multirresistentes. Se incluyen aquellas especies de mayor interés debido a su impacto clínico/epidemiológico y a las dificultades terapéuticas que generan: Staphylococcus aureus resistente a meticilina, Enterococcus spp. resistente a los glucopéptidos, enterobacterias productoras de β-lactamasas de espectro extendido o β-lactamasas plasmídicas de tipo AmpC, enterobacterias productoras de carbapenemasas, Acinetobacter baumannii multirresistente y Pseudomonas aeruginosa multirresistente. La información recogida en este documento debe considerarse como una estructura matriz que deberá adaptarse a las necesidades específicas de cada centro (AU)

The presence of colonised patients is one of the main routes for the spread of multiresistant bacteria, and its containment is a clinical and public health priority. Surveillance studies are essential for early detection of colonisation by these bacteria. This article discusses the different microbiological methods, both based on culturing and molecular methods, for detection of carriers of multiresistant bacteria. Those species with a high clinical/epidemiological impact or generating therapeutic difficulties are included: Methicillin-resistant Staphylococcus aureus, Enterococcus spp. resistant to glycopeptides, enterobacteriaceae producing extended spectrum β-lactamases and plasmid-mediated AmpC, carbapenemases producing enterobacteriaceae, Acinetobacter baumannii and multiresistant Pseudomonas aeruginosa. The information in this document should be considered as a structure matrix to be tailored to the specific needs of each centre (AU)

Carbapenem-resistant Citrobacter spp. isolated in Spain from 2013 to 2015 produced a variety of carbapenemases including VIM-1, OXA-48, KPC-2, NDM-1 and VIM-2.

OBJECTIVES: There is little information about carbapenemase-producing (CP) Citrobacter spp. We studied the molecular epidemiology and microbiological features of CP Citrobacter spp. isolates collected in Spain (2013-15). METHODS: In total, 119 isolates suspected of being CP by the EUCAST screening cut-off values were analysed. Carbapenemases and ESBLs were characterized using PCR and sequencing. The genetic relationship among Citrobacter freundii isolates was studied by PFGE. RESULTS: Of the 119 isolates, 63 (52.9%) produced carbapenemases, of which 37 (58.7%) produced VIM-1, 20 (31.7%) produced OXA-48, 12 (19%) produced KPC-2, 2 (3.2%) produced NDM-1 and 1 (1.6%) produced VIM-2; 9 C. freundii isolates co-produced VIM-1 plus OXA-48. Fourteen isolates (22.2%) also carried ESBLs: 8 CTX-M-9 plus SHV-12, 2 CTX-M-9, 2 SHV-12 and 2 CTX-M-15. Fifty-seven isolates (90.5%) were C. freundii, 4 (6.3%) were Citrobacter koseri, 1 (1.6%) was Citrobacter amalonaticus and 1 (1.6%) was Citrobacter braakii. By EUCAST breakpoints, eight (12.7%) of the CP isolates were susceptible to the four carbapenems tested. In the 53 CP C. freundii analysed by PFGE, a total of 44 different band patterns were observed. Four PFGE clusters were identified: cluster 1 included eight isolates co-producing VIM-1 and OXA-48; blaVIM-1 was carried in a class 1 integron (intI-blaVIM-1-aacA4-dfrB1-aadA1-catB2-qacEΔ1/sul1) and blaOXA-48 was carried in a Tn1999.2 transposon. CONCLUSIONS: We observed the clonal and polyclonal spread of CP Citrobacter spp. across several Spanish geographical areas. Four species of Citrobacter spp. produced up to five carbapenemase types, including co-production of VIM-1 plus OXA-48. Some CP Citrobacter spp. isolates were susceptible to the four carbapenems tested, a finding with potential clinical implications.

Prevalencia en España de mecanismos de resistencia a quinolonas en enterobacterias productoras de betalactamasas de clase C adquiridas y/o carbapenemasas / Prevalence of quinolone resistance mechanisms in Enterobacteriaceae producing acquired AmpC Beta-lactamases and/or carbapenemases in Spain

Introducción: En los últimos años se ha observado un incremento de la resistencia a fluoroquinolonas en enterobacterias, estando asociado significativamente a la resistencia a betalactámicos. Nuestro objetivo fue conocer la prevalencia de mecanismos cromosómicos y plasmídicos de resistencia a quinolonas en aislados productores de betalactamasas de claseC adquiridas y/o carbapenemasas. Métodos: Se evaluó la presencia de mecanismos cromosómicos y plasmídicos de resistencia a quinolonas [mutaciones en la región determinante de resistencia a quinolonas de gyrA y parCy genes qnr, aac(6')-Ib-cr y qepA] en 289 aislados de enterobacterias productoras de betalactamasas de claseC adquiridas y/o carbapenemasas recogidos entre febrero y julio de 2009 en 35 hospitales españoles. Resultados: Se detectaron determinantes plasmídicos en 92 aislados (31,8%); en 83 aislados (28,7%) se detectó algún gen qnr, y en 20 (7%), la variante aac(6')-Ib-cr. El gen qnr más prevalente fue qnrB4 (20%), asociado en la mayoría de los casos a DHA-1. El 14,6% de los aislados con una CMI de ciprofloxacino superior a 0,25mg/l no presentaban mutaciones en gyrA ni parC, detectándose en el 90% de los mismos algún determinante plasmídico de resistencia a quinolonas. Conclusión: qnrB4 fue el determinante plasmídico más prevalente, claramente asociado a DHA-1. Los mecanismos plasmídicos en asociación con mecanismos cromosómicos diferentes a las mutaciones en los genes de las topoisomerasas (sobreexpresión de bombas de expulsión, alteración del lipopolisacárido o disminución de porinas) pueden dar lugar a valores de CMI de ciprofloxacino que superan los puntos de corte establecidos por los principales comités internacionales de definición de puntos de corte para interpretación de datos de sensibilidad (AU)

Background: Quinolone resistance in Enterobacteriaceae species has increased over the past few years, and is significantly associated to beta-lactam resistance. The aim of this study was to evaluate the prevalence of chromosomal- and plasmid-mediated quinolone resistance in acquired AmpC Beta-lactamase and/or carbapenemase-producing Enterobacteriaceae isolates. Methods: The presence of chromosomal- and plasmid-mediated quinolone resistance mechanisms [mutations in the quinolone resistance determining region (QRDR) of gyrA and parC and qnr, aac(6')-Ib-cr and qepA genes] was evaluated in 289 isolates of acquired AmpC Beta -lactamase- and/or carbapenemase-producing Enterobacteriaceae collected between February and July 2009 in 35 Spanish hospitals. Results: Plasmid mediated quinolone resistance (PMQR) genes were detected in 92 isolates (31.8%), qnr genes were detected in 83 isolates (28.7%), and the aac(6')-Ib-cr gene was detected in 20 isolates (7%). qnrB4 gene was the most prevalent qnr gene detected (20%), associated, in most cases, with DHA-1. Only 14.6% of isolates showed no mutations in gyrA or parC with a ciprofloxacin MIC of 0.5mg/L or higher, whereas PMQR genes were detected in 90% of such isolates. Conclusion: qnrB4 gene was the most prevalent PMQR gene detected, and was significantly associated with acquired AmpC Beta -lactamase DHA-1. PMQR determinants in association with other chromosomal-mediated quinolone resistance mechanisms, different to mutations in gyrA and parC (increased energy-dependent efflux, altered lipopolysaccharide or porin loss), could lead to ciprofloxacin MIC values that exceed breakpoints established by the main international committees to define clinical antimicrobial susceptibility breakpoints (AU)

¿Deben implantarse programas de cribado de cepas productoras de carbapenemasas en pacientes que ingresan en la UCI? / Should screening programs for carbapenemase-producing strains be implemented in ICU patients?

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The Carbapenemase-Producing Klebsiella pneumoniae Population Is Distinct and More Clonal than the Carbapenem-Susceptible Population.

We studied in parallel the population structure of 90 carbapenemase-producing and 88 carbapenemase-susceptible Klebsiella pneumoniae isolates collected in 20 Spanish hospitals, in the context of the EuSCAPE project. Fourteen and 50 multilocus sequence types (MLSTs) were detected among the carbapenemase-producing and carbapenem-susceptible isolates, respectively. ST11 and ST15 clones were more frequent in the carbapenemase-producing group than in the carbapenemase-susceptible group (P < 0.0001). Among the members of the carbapenem-suceptible group, the cefotaxime-resistant population showed population parameters that differed between the populations of the wild-type strains and the carbapenemase producers.

Prevalence of quinolone resistance mechanisms in Enterobacteriaceae producing acquired AmpC ß-lactamases and/or carbapenemases in Spain. / Prevalencia en España de mecanismos de resistencia a quinolonas en enterobacterias productoras de betalactamasas de clase C adquiridas y/o carbapenemasas.

BACKGROUND: Quinolone resistance in Enterobacteriaceae species has increased over the past few years, and is significantly associated to beta-lactam resistance. The aim of this study was to evaluate the prevalence of chromosomal- and plasmid-mediated quinolone resistance in acquired AmpC ß-lactamase and/or carbapenemase-producing Enterobacteriaceae isolates. METHODS: The presence of chromosomal- and plasmid-mediated quinolone resistance mechanisms [mutations in the quinolone resistance determining region (QRDR) of gyrA and parC and qnr, aac(6')-Ib-cr and qepA genes] was evaluated in 289 isolates of acquired AmpC ß-lactamase- and/or carbapenemase-producing Enterobacteriaceae collected between February and July 2009 in 35 Spanish hospitals. RESULTS: Plasmid mediated quinolone resistance (PMQR) genes were detected in 92 isolates (31.8%), qnr genes were detected in 83 isolates (28.7%), and the aac(6')-Ib-cr gene was detected in 20 isolates (7%). qnrB4 gene was the most prevalent qnr gene detected (20%), associated, in most cases, with DHA-1. Only 14.6% of isolates showed no mutations in gyrA or parC with a ciprofloxacin MIC of 0.5mg/L or higher, whereas PMQR genes were detected in 90% of such isolates. CONCLUSION: qnrB4 gene was the most prevalent PMQR gene detected, and was significantly associated with acquired AmpC ß-lactamase DHA-1. PMQR determinants in association with other chromosomal-mediated quinolone resistance mechanisms, different to mutations in gyrA and parC (increased energy-dependent efflux, altered lipopolysaccharide or porin loss), could lead to ciprofloxacin MIC values that exceed breakpoints established by the main international committees to define clinical antimicrobial susceptibility breakpoints.

Microbiological methods for surveillance of carrier status of multiresistant bacteria. / Métodos microbiológicos para la vigilancia del estado de portador de bacterias multirresistentes.

The presence of colonised patients is one of the main routes for the spread of multiresistant bacteria, and its containment is a clinical and public health priority. Surveillance studies are essential for early detection of colonisation by these bacteria. This article discusses the different microbiological methods, both based on culturing and molecular methods, for detection of carriers of multiresistant bacteria. Those species with a high clinical/epidemiological impact or generating therapeutic difficulties are included: Methicillin-resistant Staphylococcus aureus, Enterococcus spp. resistant to glycopeptides, enterobacteriaceae producing extended spectrum ß-lactamases and plasmid-mediated AmpC, carbapenemases producing enterobacteriaceae, Acinetobacter baumannii and multiresistant Pseudomonas aeruginosa. The information in this document should be considered as a structure matrix to be tailored to the specific needs of each centre.