The unexpected high prevalence of HBV subgenotype D4 in patients with chronic hepatitis B in Galicia, a northwestern Spanish region, reflects strong links with Latin America.

BACKGROUND: Hepatitis B virus (HBV) comprises 9 genotypes and multiple subgenotypes that depict differences in geographic distribution, clinical outcome and response to antiviral therapy. However, the molecular epidemiology of HBV geno/subgenotypes is globally scarce. In Spain, HBV genotype D seems to be more prevalent in the northwestern regions compared to the rest of the country for unclear reasons. METHODS: HBV genotyping was performed using geno2pheno on a S gene fragment amplified from plasma collected from all chronic hepatitis B individuals attended at one reference hospital in Santiago de Compostela, the Galicia's capital town. Phylogenetic and phylogeographic analyses using a fragment of 345 bp were performed in all viremic specimens. To avoid misleading allocation as consequence of short fragment analysis, several bioinformatic controls were used. RESULTS: A total of 320 individuals with persistent serum HBsAg+ and detectable HBV-DNA were seen between 2000 and 2016 (male 68.4%; median age, 52 years-old; native Spaniards 83.8%). HBV genotype distribution was as follows: A 15.3%; B 1.6%; C 2.5%; D 71.6%; E 3.1%; F 2.2%; G 3.1%; and H 0.6%. HBV genotype D was mostly represented by D4 and D2 subgenotypes (33.4% and 15% of total, respectively). Compared to chronic hepatitis B patients with genotypes B, C, E and G, HBV-D4 carriers tended to be older (54.2% had >50 years-old) and HBeAg-negative (85%). Moreover, 43% were female, 4.7% had cirrhosis, 10.2% hepatitis C and 6.4% HIV coinfection. Phylogenetic analyses could be performed on 82 HBV-D4 specimens; and 79 were confirmed as HBV-D4 using PhyML. Phylogeography using FasTree suggested at least two distinct introductions of HBV-D4 in Galicia, one from the Caribbean and South America, and another from India. CONCLUSIONS: HBV subgenotype D4 is the most prevalent HBV variant in chronic hepatitis B patients living in the northwest of Spain, representing 33.4% (107/320) of all chronic hepatitis B infections. This rate of HBV-D4 is among the highest reported worldwide. Epidemiological and phylogenetic analyses suggest a strong association with historical migrant exchanges with Latin America, and especially with the Caribbean basin.

Risk Factors of Mortality in Hospitalized Patients With COVID-19 Applying a Machine Learning Algorithm.

Introduction: Risk stratification of patients with COVID-19 can be fundamental to support clinical decision-making and optimize resources. The objective of our study is to identify among the routinely tested clinical and analytical parameters those that would allow us to determine patients with the highest risk of dying from COVID-19. Material and methods: We carried out a retrospective cohort multicentric study by consecutively, including hospitalized patients with COVID-19 admitted in any of the 11 hospitals in the healthcare network of HM Hospitals-Spain. We collected the clinical, demographic, analytical, and radiological data from the patient's medical records.To assess each of the biomarkers' predictive impact and measure the statistical significance of the variables involved in the analysis, we applied a random forest with a permutation method. We used the similarity measure induced by a previously classification model and adjusted the k-groups clustering algorithm based on the energy distance to stratify patients into a high and low-risk group. Finally, we adjusted two optimal classification trees to have a schematic representation of the cut-off points. Results: We included 1246 patients (average age of 65.36 years, 62% males). During the study one hundred sixty-eight patients (13%) died. High values of age, D-Dimer, White Blood Cell, Na, CRP, and creatinine represent the factors that identify high-risk patients who would die. Conclusions: Age seems to be the primary predictor of mortality in patients with SARS-CoV-2 infection, while the impact of acute phase reactants and blood cellularity is also highly relevant.

Introducción: La estratificación del riesgo de los pacientes con COVID-19 puede ser fundamental para apoyar la toma de decisiones clínicas y optimizar los recursos. El objetivo de nuestro estudio es identificar, entre los parámetros clínicos y analíticos probados de forma rutinaria, aquellos que nos permitirían determinar a los pacientes con mayor riesgo de morir por COVID-19. Material y métodos: Se realizó un estudio multicéntrico de cohorte retrospectiva de forma consecutiva, incluyendo pacientes hospitalizados con COVID-19 ingresados en cualquiera de los 11 hospitales de la red sanitaria de HM Hospitales-España.Los datos clínicos, demográficos, analíticos y radiológicos se recopilaron de las historias clínicas de los pacientes.Para evaluar el impacto predictivo de cada uno de los biomarcadores y medir la significación estadística de las variables involucradas en el análisis, se aplicó un bosque aleatorio con un método de permutación. Utilizamos la medida de similitud inducida por un modelo de clasificación previo, y ajustamos el algoritmo de agrupación de grupos k en función de la distancia de energía para estratificar a los pacientes en un grupo de alto y bajo riesgo. Finalmente, ajustamos 2 árboles de clasificación óptimos para tener una representación esquemática de los puntos de corte. Resultados: Se incluyeron 1.246 pacientes (edad promedio de 65,36 años, 62% varones). Durante el estudio murieron 168 pacientes (13%). Los factores que identifican a los pacientes de alto riesgo de mortalidad son los valores elevados de edad, dímero D, glóbulos blancos, Na, PCR y creatinina. Conclusiones: La edad parece ser el principal predictor de mortalidad en pacientes con infección por SARS-CoV-2, mientras que el impacto de los reactantes de fase aguda y la celularidad sanguínea también es muy relevante.

Sample pooling for SARS-CoV-2 RT-PCR screening.

OBJECTIVE: To evaluate the efficacy of sample pooling compared to the individual analysis for the diagnosis of coronavirus disease 2019 (COVID-19) by using different commercial platforms for nucleic acid extraction and amplification. METHODS: A total of 3519 nasopharyngeal samples received at nine Spanish clinical microbiology laboratories were processed individually and in pools (342 pools of ten samples and 11 pools of nine samples) according to the existing methodology in place at each centre. RESULTS: We found that 253 pools (2519 samples) were negative and 99 pools (990 samples) were positive; with 241 positive samples (6.85%), our pooling strategy would have saved 2167 PCR tests. For 29 pools (made out of 290 samples), we found discordant results when compared to their correspondent individual samples, as follows: in 22 of 29 pools (28 samples), minor discordances were found; for seven pools (7 samples), we found major discordances. Sensitivity, specificity and positive and negative predictive values for pooling were 97.10% (95% confidence interval (CI), 94.11-98.82), 100%, 100% and 99.79% (95% CI, 99.56-99.90) respectively; accuracy was 99.80% (95% CI, 99.59-99.92), and the kappa concordant coefficient was 0.984. The dilution of samples in our pooling strategy resulted in a median loss of 2.87 (95% CI, 2.46-3.28) cycle threshold (Ct) for E gene, 3.36 (95% CI, 2.89-3.85) Ct for the RdRP gene and 2.99 (95% CI, 2.56-3.43) Ct for the N gene. CONCLUSIONS: We found a high efficiency of pooling strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA testing across different RNA extraction and amplification platforms, with excellent performance in terms of sensitivity, specificity and positive and negative predictive values.

Estudio de sensibilidad de Escherichia coli productores de infecciones del tracto urinario comunitarias en Galicia. Período: 2016-2017 / Antimicrobial susceptibility of Escherichia coli producers of community urinary tract infections in Galicia (Spain). Period: 2016-2017

OBJETIVO: Escherichia coli (E. coli) es el responsable de la mayoría de las infecciones del tracto urinario comunitarias. El objetivo del estudio es conocer el espectro de sensibilidad de E. coli en infecciones del tracto urinario para recomendar el tratamiento antibiótico empírico adecuado. DISEÑO: Estudio transversal, multicéntrico, retrospectivo. EMPLAZAMIENTO: Ocho hospitales públicos gallegos, prácticamente toda la población de Galicia (España). PARTICIPANTES: Cuarenta y tres mil ciento treinta y siete pacientes ambulatorios con infección del tracto urinario por E. coli aislados en orina en 2016/2017. MEDICIONES PRINCIPALES: Variables analizadas: demográficas, concentración mínima inhibitoria e interpretación de la sensibilidad según criterios de CLSI y mecanismos de resistencia. Los antibióticos estudiados fueron: ampicilina, amoxicilina-ácido clavulánico, ciprofloxacino, cefotaxima, cefepime, gentamicina, nitrofurantoína, fosfomicina, cotrimoxazol, imipenem y ertapenem. La identificación y sensibilidad se hicieron principalmente por sistemas automatizados. RESULTADOS: Los porcentajes de no sensibilidad de los aislamientos de E. coli fueron: ampicilina 49,2%, amoxicilina-ácido clavulánico 17,8%, cefotaxima 6,7%, cefepime 5,7%, ertapenem 0,04%, imipenem 0,05%, gentamicina 9,1%, ciprofloxacino 26,2%, fosfomicina 3,3%, nitrofurantoína 2,4% y cotrimoxazol 23,9%. Las no sensibilidades fueron superiores en hombres y a medida que aumenta la edad. El 6% fueron productores de betalactamasas de espectro extendido. CONCLUSIONES: El tratamiento empírico en Galicia para cistitis no complicadas producidas por E. coli en mujeres continúa siendo nitrofurantoína y fosfomicina. En hombres menores de 15 años se indica fosfomicina y en hombres mayores de 15 años el tratamiento en nuestro medio debe incluir la realización de cultivo y administrar una cefalosporina de 3.a generación oral empíricamente. No se recomienda cotrimoxazol ni ciprofloxacino como tratamiento empírico por sus altos porcentajes de resistencia

OBJECTIVE: Escherichia coli (E. coli) is responsible for the majority of community urinary tract infections. The objective of the study is to know the sensitivity spectrum of E. coli in urinary tract infections to be able to recommend the appropriate empirical antibiotic treatment. DESIGN: Cross-sectional, multicentric, retrospective study. LOCATION: Galician 8 public hospitals, practically the entire population of Galicia (Spain). PARTICIPANTS: 43,137 outpatients with urinary tract infection due to E. coli isolated in urine in 2016/2017. MAIN MEASUREMENTS: Analyzed variables: demographic, minimum inhibitory concentration and interpretation of sensitivity according to CLSI criteria and resistance mechanisms. The antibiotics studied were: ampicillin, amoxicillin-clavulanic acid, ciprofloxacin, cefotaxime, cefepime, gentamicin, nitrofurantoin, fosfomycin, cotrimoxazole, imipenem and ertapenem. The identification and sensitivity were made mainly by automated methods. RESULTS: The percentages of non-sensitivity of E. coli isolates were: ampicillin 49.2%, amoxicillin-clavulanic acid 17.8%, cefotaxime 6.7%, cefepime 5.7%, ertapenem 0.04%, imipenem 0.05%, gentamicin 9,1%, ciprofloxacin 26.2%, fosfomycin 3.3%, nitrofurantoin 2.4% and cotrimoxazole 23.9%. The non-sensitivities were higher in men and as age increases. Six percent of E. coli were producers of extended-spectrum beta-lactamases. CONCLUSIONS: The empirical treatment in Galicia for uncomplicated cystitis produced by E. coli in women continues to be nitrofurantoin and fosfomycin. In men under 15 years of age, fosfomycin is indicated and in men older than 15 years, treatment in our environment should include culture and administer a 3rd generation oral cephalosporin empirically. Cotrimoxazole and ciprofloxacin are not recommended as empirical treatment because of their high resistance rates

[Antimicrobial susceptibility of Escherichia coli producers of community urinary tract infections in Galicia (Spain). Period: 2016-2017]. / Estudio de sensibilidad de Escherichia coli productores de infecciones del tracto urinario comunitarias en Galicia. Período: 2016-2017.

OBJECTIVE: Escherichia coli (E. coli) is responsible for the majority of community urinary tract infections. The objective of the study is to know the sensitivity spectrum of E. coli in urinary tract infections to be able to recommend the appropriate empirical antibiotic treatment. DESIGN: Cross-sectional, multicentric, retrospective study. LOCATION: Galician 8 public hospitals, practically the entire population of Galicia (Spain). PARTICIPANTS: 43,137 outpatients with urinary tract infection due to E. coli isolated in urine in 2016/2017. MAIN MEASUREMENTS: Analyzed variables: demographic, minimum inhibitory concentration and interpretation of sensitivity according to CLSI criteria and resistance mechanisms. The antibiotics studied were: ampicillin, amoxicillin-clavulanic acid, ciprofloxacin, cefotaxime, cefepime, gentamicin, nitrofurantoin, fosfomycin, cotrimoxazole, imipenem and ertapenem. The identification and sensitivity were made mainly by automated methods. RESULTS: The percentages of non-sensitivity of E. coli isolates were: ampicillin 49.2%, amoxicillin-clavulanic acid 17.8%, cefotaxime 6.7%, cefepime 5.7%, ertapenem 0.04%, imipenem 0.05%, gentamicin 9,1%, ciprofloxacin 26.2%, fosfomycin 3.3%, nitrofurantoin 2.4% and cotrimoxazole 23.9%. The non-sensitivities were higher in men and as age increases. Six percent of E. coli were producers of extended-spectrum beta-lactamases. CONCLUSIONS: The empirical treatment in Galicia for uncomplicated cystitis produced by E. coli in women continues to be nitrofurantoin and fosfomycin. In men under 15 years of age, fosfomycin is indicated and in men older than 15 years, treatment in our environment should include culture and administer a 3rd generation oral cephalosporin empirically. Cotrimoxazole and ciprofloxacin are not recommended as empirical treatment because of their high resistance rates.

Influenza A H1N1 Community-Acquired Pneumonia: Characteristics and Risk Factors-A Case-Control Study.

Introduction: Influenza A H1N1 community-acquired pneumonia (CAP) is a quite frequent respiratory disease. Despite being considered more serious than other CAPs, there are very few studies comparing its characteristics with noninfluenza CAP. We aim to establish the differences between pneumonia due to H1N1 virus and pneumonia not caused by H1N1 influenza virus and to determine the probability that a pneumonia is due to an H1N1 virus infection based on the most relevant variables. Methods: We used a case-control study where cases were H1N1 CAP patients with confirmed microbiological diagnosis and controls were patients with CAP admitted to hospital. H1N1 and other influenza types were discarded among controls. We calculated the probability of being a case or control using multivariate logistic regression. Results: We included 99 cases and 270 controls. Cases were younger than controls (53 vs 71 years, respectively). Mortality was much higher for H1N1 patients (13% vs 0.3%), and admission to intensive care unit was more frequent for H1N1 cases. The variables most associated with presenting H1N1 CAP were bilateral affectation on chest X-rays (OR: 5.70; 95% CI 2.69-10.40), followed by presence of arthromyalgias, with cases presenting close to three times more arthromyalgias compared to controls. Low leukocytes count and high AST values were also significantly associated with H1N1 CAP. H1N1 CAPs are characterized by bilateral affectation, low leukocyte count, presence of arthromyalgias, and high AST. Conclusions: A few and easy to obtain clinical parameters might be extremely useful to distinguish H1N1 CAP from CAPs of other origin.

Coinfección pulmonar por Nocardia cyriacigeorgica y Aspergillus fumigatus / Pulmonary co-infection due to Nocardia cyriacigeorgica and Aspergillus fumigatus

Introducción. La nocardiosis pulmonar es una infección poco frecuente causada por bacterias grampositivas aerobias del género Nocardia. Nocardia sp. son microorganismos ambientales de distribución ubicua. Se han descrito unas 50 especies de Nocardia y 30 de ellas se sabe que causan infección en seres humanos. Nocardia cyriacigeorgica se describe por primera vez en 2001. Caso clínico. Presentamos un caso de infección por N. cyriacigeorgica en paciente con historia de linfoma no Hodgkin de células B y diabetes mellitus. Los hallazgos microbiológicos reflejan una posible coinfección por N. cyriacigeorgica y Aspergillus fumigatus. Conclusiones. Los datos de factores de riesgo y antecedentes son fundamentales para detectar el crecimiento de Nocardia sp. en el laboratorio. Por otra parte, el diagnóstico de la aspergilosis pulmonar invasiva es particularmente controvertida, especialmente en los paciente de unidades de cuidados intensivos. Teniendo todo en cuenta, presentamos un caso de una posible coinfección por N. cyriacigeorgica and A. fumigatus en un paciente crítico (AU)

Introduction. Pulmonary nocardiosis is an uncommon pulmonary infection caused by aerobic gram-positive bacteria of the genus Nocardia. Nocardia sp. are environmental organisms spread worldwide. Approximately 50 Nocardia species have been described to date, about 30 of which are known to cause human disease. Nocardia cyriacigeorgica was first reported in 2001. Case report. We report a case of infection caused by N. cyriacigeorgica in a patient with B-cells non-Hodgkin lymphoma and diabetes mellitus. The microbiological findings reflect a possible co-infection by N. cyriacigeorgica and Aspergillus fumigatus. Conclusions. Patient’s background and information related to risk factors are essential to detect the growth of Nocardia sp. in the laboratory. Furthermore, diagnosis of invasive pulmonary aspergillosis is particularly controversial, especially in intensive care units patients. Taking everything into account, we will discuss a possible co-infection by N. cyriacigeorgica and A. fumigatus in a critically ill patient (AU)

[Plasmid-mediated AMPc producing Proteus mirabilis in the Health Care Area of Santiago de Compostela: molecular and epidemiological analysis by rep-PCR and MALDI-TOF]. / Proteus mirabilis productor de AmpC plasmídica en el Área Sanitaria de Santiago de Compostela: prevalencia y caracterización molecular por rep-PCR y MALDI-TOF MS.

INTRODUCTION: Proteus mirabilis is an important pathogen isolated from both community-acquired and health-care associated infections. Acquired AmpC-type beta-lactamases represent an important mechanism of resistance to extended-spectrum cephalosporins and are emerging in several European countries. The objective of this work was to know the prevalence of acquired AmpC beta-lactamase producing P. mirabilis over the last three years and eight months and their clonal relationships comparing MALDI-TOF and automated rep-PCR results. METHODS: P. mirabilis isolates (n= 1,396) were obtained from routine cultures at the University Hospital Complex of Santiago de Compostela from January 2006 to August 2009. Identification to the species level and antimicrobial susceptibility testing were achieved with Vitek 2. The isolates showing intermediate or total resistance to amoxicillin-clavulanic and cefoxitin, cefotaxime or ceftazidime were selected for AmpC phenotypic detection by double-disk synergy test, and molecular confirmation by multiplex PCR. Molecular typing of the isolates was performed by automated rep-PCR and MALDI-TOF. RESULTS: For the last three years and eight months, the prevalence of AmpC-producing P. mirabilis increased from 0.17% to 4.5%, mainly associated with urinary tract infection in elderly outpatients. In all cases, plasmidic AmpC belonging to LAT/CMY lineage were detected. A high genetic variability was seen with both, rep-PCR and MALDI-TOF MS. CONCLUSIONS: AmpC-producing P. mirabilis is an emergent pathogen. The high genetic variability detected suggests that the spread of the resistance mechanism is more probable than a clone dispersion. Automated rep-PCR and MALDI-TOF MS show as fast and decisive methods for bacterial strain typing in clinical microbiology laboratories.

Proteus mirabilis productor de AmpC plasmídica en el Área Sanitaria de Santiago de Compostela: prevalencia y caracterización molecular por rep-PCR y MALDI-TOF MS / Plasmid-mediated AMPc producing Proteus mirabilis in the Health Care Area of Santiago de Compostela: molecular and epidemiological analysis by rep-PCR and MALDI-TOF

Introducción: Proteus mirabilis es un patógeno de importancia creciente tanto en las infecciones nosocomiales como en las comunitarias. La producción de AmpC plasmídica es un mecanismo de resistencia frente a cefalosporinas de espectro extendido emergente en esta bacteria por lo que se consideró de gran interés estudiar su prevalencia en nuestro Área Sanitaria así como su variabilidad genética, comparando dos métodos recientemente incorporados al mercado: MALDI-TOF y rep-PCR automatizada. Métodos: Entre enero de 2006 y agosto de 2009 se recuperaron 1.396 aislamientos de P. mirabilis a partir de los cultivos de rutina realizados en Complejo Hospitalario Universitario de Santiago de Compostela. La identificación y el antibiograma se hicieron por Vitek 2. Aquellos aislamientos con sensibilidad reducida a amoxicilina-clavulánico y a cefoxitina, cefotaxima o ceftazidima fueron seleccionados para la detección fenotípica y genotípica de AmpC plasmídica mediante sinergia con doble disco y PCR múltiple, respectivamente. La tipificación molecular se llevó a cabo, comparativamente, mediante rep-PCR automatizada y MALDI-TOF. Resultados: A lo largo de tres años y ocho meses, la prevalencia de P. mirabilis productor de AmpC pasó del 0,17% al 4,5%, mayoritariamente asociado a infección urinaria en pacientes ancianos no hospitalizados. En todos los casos, AmpC plasmídica perteneció a la familia LAT/CMY. Se observó una gran variabilidad genética entre los aislamientos tanto por rep-PCR (DiversiLab) como por MALDI-TOF MS. Conclusión: P. mirabilis productor de AmpC adquirida es un patógeno emergente. La variabilidad genética de las cepas estudiadas apunta a una dispersión de este mecanismo de resistencia más que a una diseminación clonal. Rep-PCR automatizada y MALDI-TOF se muestran como métodos rápidos y resolutivos para la tipificación molecular en los laboratorios de microbiología clínica(AU)

Introduction: Proteus mirabilis is an important pathogen isolated from both community-acquired and health-care associated infections. Acquired AmpC-type beta-lactamases represent an important mechanism of resistance to extended-spectrum cephalosporins and are emerging in several European countries. The objective of this work was to know the prevalence of acquired AmpC beta-lactamase producing P. mirabilis over the last three years and eight months and their clonal relationships comparing MALDI-TOF and automated rep-PCR results. Methods: P. mirabilis isolates (n= 1,396) were obtained from routine cultures at the University Hospital Complex of Santiago de Compostela from January 2006 to August 2009. Identification to the species level and antimicrobial susceptibility testing were achieved with Vitek 2. The isolates showing intermediate or total resistance to amoxicillin-clavulanic and cefoxitin, cefotaxime or ceftazidime were selected for AmpC phenotypic detection by double-disk synergy test, and molecular confirmation by multiplex PCR. Molecular typing of the isolates was performed by automated rep-PCR and MALDI-TOF. Results: For the last three years and eight months, the prevalence of AmpC-producing P. mirabilis increased from 0.17% to 4.5%, mainly associated with urinary tract infection in elderly outpatients. In all cases, plasmidic AmpC belonging to LAT/CMY lineage were detected. A high genetic variability was seen with both, rep-PCR and MALDI-TOF MS. Conclusions: AmpC-producing P. mirabilis is an emergent pathogen. The high genetic variability detected suggests that the spread of the resistance mechanism is more probable than a clone dispersion. Automated rep-PCR and MALDI-TOF MS show as fast and decisive methods for bacterial strain typing in clinical microbiology laboratories(AU)

Molecular and epidemiological analysis of nosocomial carbapenem-resistant Klebsiella spp. using repetitive extragenic palindromic-polymerase chain reaction and matrix-assisted laser desorption/ionization-time of flight.

INTRODUCTION: Infections with carbapenem-resistant enterobacteria are an emerging threat. This study reports the microbiologic, clinical, and epidemiologic features and the therapeutic outcomes of the infections caused by carbapenem- and pandrug-resistant Klebsiella emerged in our hospital. Fingerprinting analyses by automated repetitive extragenic palindromic-polymerase chain reaction (rep-PCR) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry are also compared. MATERIALS AND METHODS: Carbapenem-resistant Klebsiella spp. affecting 13 patients were investigated using automated rep-PCR (DiversiLab System) and MALDI-TOF. Species identification was performed by Vitek 2 System and MALDI-TOF. Antimicrobial susceptibility testing was made using Vitek 2 System and Etest. Screening for extended spectrum beta-lactamase (ESBL) and carbapenemase production was made by double disk synergy and Hodge tests, respectively. Synergy studies were performed using Etest. DNA array was used for detection of KPC and ESBLs. bla(VIM-1) gene was amplified by PCR and sequencing. Use of carbapenems in the hospital was studied. RESULTS: A total of 13 patients were found to be colonized/infected with carbapenem-resistant Klebsiella. All patients were previously submitted to surgery and/or presented with severe underlying disease. After carbapenem-resistant Klebsiella isolation, the majority of the patients were treated with amikacin plus carbapenem, tigecycline, or fosfomycin. All Klebsiella isolates (n = 14), except two, had the bla(VIM-1) gene and all Klebsiella pneumoniae also had bla(SHV) gene associated with ESBL production. DiversiLab system showed higher discriminatory power than MALDI-TOF for strain typing. CONCLUSIONS: The risk of a rapid dissemination and the persistence of these multidrug-resistant strains through the time determine the need to implement routine procedures for metallo-beta-lactamase detection and measures for prevention of the spread of these microorganisms. The combined use of MALDI-TOF for species identification and DiversiLab System for clonal strain typing may be a useful tool for fast and accurate management of nosocomial outbreaks. The potential clinical utility of fosfomycin in this matter should be considered in future studies.