Rev Esp Quimioter 2013:26(1):47-50

Detection and genotyping of human respiratory viruses in clinical specimens from children with acute respiratory tract infections 
                                  

E. CULEBRAS, C. BETRIU, E. VÁZQUEZ-CID, E. LÓPEZ-VARELA, S. RUEDA, J. J. PICAZO                     

Respiratory virus infections are a major health concern and represent the primary cause of testing consultation and hospitalization for young children. The application of nucleic acid amplification technology, particularly multiplex PCR coupled with fluidic or fixed microarrays, provides an important new approach for the detection of multiple respiratory viruses in a single test. The aim of this study was to analyze respiratory samples from children with acute respiratory tract infection (ARTI) using a commercial array-based method (CLART® PneumoVir Genomica, Coslada, Spain). These tests were used to identify viruses in 281 nasopharyngeal samples obtained from children affected by ARTI. Samples were obtained form October 2008 to April 2009. Viruses were identified in 80% of the studied ARTI providing useful information on clinical features and epidemiology of specific agents affecting children in cold months. Multiple viral infections were found in 33.45% of the specimens.

Rev Esp Quimioter 2013:26(1):47-50 [pdf]

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Rev Esp Quimioter 2013:26(3):193-197

Identification of fungal clinical isolates by matrix-assisted laser desorption
ionization-time-of-flight mass spectrometry                                
 

LAURA FERREIRA, FERNANDO SÁNCHEZ-JUANES, SILVIA VEGA, MAGDALENA GONZÁLEZ, Mª INMACULADA GARCÍA, SILVIA RODRÍGUEZ, JOSÉ MANUEL GONZÁLEZ-BUITRAGO, JUAN LUIS MUÑOZ-BELLIDO
             

Background. Recently, bacterial identification by MALDI-TOF MS has acquired a high relevance in terms of speed and reliability. Conventional mycological identification has some disadvantages: it is frequently slow, reliability is sometimes low, and an extensive experience is required. The risk population for fungal infections, and therefore their clinical significance has progressively increased in recent years.
Methods. 153 yeast and mould clinical isolates were analyzed by MALDI-TOF MS and conventional identification. When both methods were discrepant to the genus or species level, ITS-2 sequencing was performed.
Results. The correlation in yeasts identification between conventional identification methods and MALDI-TOF MS was extremely high (99.2% to the species level and 100% to the genus level). The only discrepancy was checked by ITS-2 sequencing and confirmed the MALDI-TOF identification. The correlation in moulds identification was more heterogeneous. 68.7% of the isolates showed correlation at least to the genus level and 40.6% to the species level. Therefore, the correlation between conventional identification and MALDI-TOF MS in fungal identification was, in whole, 87% to the species level, and 93.5% to the genus level.
Conclusions. Identification of fungi by MALDI-TOF MS is reliable and shows potential advantages over conventional identification methods.

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Rev Esp Quimioter 2013:26(1):51-55

Candida sp endocarditis. Experience in a third level hospital and review of the literature 
                                  

A.HERNÁNDEZ-TORRES, E. GARCÍA-VÁZQUEZ, A. LASO-ORTIZ, J. A. HERRERO-MARTÍNEZ, J. GÓMEZ-GÓMEZ                      

Despite the relative high frequency of Candida bloodstream infection, Candida endocarditis is a rare entity. We report five cases of Candida endocarditis admitted to our hospital in the period between 2005 and 2011. Two cases were caused by C. albicans, two cases were caused by C. parapsilosis and in the last one, we didn´t identify the species of Candida. All but one had clear risk factors for candidemia. Treatment consisted of amphotericin B with / without flucytosine in four patients, and they all underwent surgery for valve replacement and / or removal of intravascular devices. Overall mortality was 60% (40% of mortality was directly related to endocarditis). All patients who survived were given suppressive therapy with fluconazole for a minimum of two years. After stopping fluconazole there was a case of recurrence.

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Rev Esp Quimioter 2013:26(3):198-202

Psoas abscess associated with hip arthroplasty infection                                 
 

IBON LÓPEZ-ZABALA, SEBASTIÁN GARCÍA-RAMIRO, GUILLEM BORI, XAVIER GALLART, XAVIER TOMÁS,DAVID FUSTER, JOSEP MENSA, ALEX SORIANO
             

Introduction. Psoas abscess associated with hip arthroplasty infection is a rare entity. The aim of this report was to review our experience.
Material and methods. Patients with computerized tomography (CT) diagnosis of psoas abscess associated with a hip arthroplasty infection from 2004 to 2009 were retrospectively reviewed. Demographics, microbiological data, CT results and outcome of each patient were recorded.
Results. Seven patients out of 214 evaluated by CT due to hip infection suspected were identified. Three women and 4 men, with a mean age of 69 years (range 46-89). Mean abscess diameter was of 62x47mm. In all cases, a direct communication between abscess and prosthesis was observed. The most commonly isolated microorganisms were grampositive cocci. All patients were treated with two-stage revision surgery. After a mean follow-up of 65 months (28-113), six patients were in remission.
Conclusions. The use of CT in the study of suspected infection of a hip arthroplasty identified a psoas abscess in 7 cases out of 214 evaluated. Patients treated with two-stage revision surgery and large debridement was associated with a good clinical outcome.

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Rev Esp Quimioter 2013:26(1):56-63

Use of tigecycline in critically ill patients with serious nosocomial intra-abdominal infections 
                                  

E. MASEDA, S. E. DENIS, A. RIQUELME, F. GILSANZ                        

Intra-abdominal infection (IAI) is a frequent complication found in surgical intensive care unit (SICU) and continues to be associated with considerable mortality. Tigecycline, the first-in-class glycylcycline has demonstrated a broad spectrum of activity against a wide range of bacteria commonly found in IAI. This observational retrospective study aimed to describe the experience with tigecycline for serious nosocomial IAI in the SICU. Data were collected from 23 consecutive patients admitted to SICU with serious nococomial IAI who had received empirical treatment with tigecycline. In all cases, IAI was diagnosed via emergency surgery. Severe sepsis was found in 56.5% and 43.5% developed septic shock. Oncological disease was the most common comorbidity (60%). The mean Simplified Acute Physiology Score (SAPS) III within 24 hours from IAI diagnosis was 57.5±14.7, and 87% showed a McCabe score >1 (2 or 3). Escherichia coli was the most common pathogen (43.5%), followed by Bacteroides spp. and Streptococcus spp. (30.4%, respectively). All but one patient received tigecycline in combination (95.7%), particularly with fluconazole (52.2%), followed by piperacillin-tazobactam (43.5%). Empirical antibiotic therapy was considered adequate in 95%. The mean duration of treatment was 8.5±4.5 days. A favorable response was achieved in 78%. Failure of the antibiotic therapy was not observed in any patient. None of the patients discontinued tigecycline due to adverse reactions. SICU mortality was 13%, with no deaths attributable to tigecycline. These findings suggest that tigecycline combination therapy is an effective and well tolerated empirical treatment of serious nosocomial IAI in the SICU.

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Rev Esp Quimioter 2013:26(3):203-213

Study of a cohort of patients with Enterococcus spp. Bacteraemia. Risk factors associated to high-level resistance to aminoglycosides                                
 

ELISA GARCÍA-VÁZQUEZ, HELENA ALBENDÍN, ALICIA HERNÁNDEZ-TORRES, MANUEL CANTERAS, GENOVEVA YAGÜE, JOAQUÍN RUIZ, JOAQUÍN GÓMEZ
             

Objectives. To analyze a cohort of patients with Enterococcus sp. bacteraemia.
Patients and methods. Retrospective and observational study of a cohort of non-pediatric in-patients with Enterococcus spp. bacteraemia (June 2007-September 2009). Data collection from clinical records was done according to a standard protocol. We analyzed epidemiological, clinical and microbiological data. Treatment with glycopeptides in non allergic patients or in case of betalactam susceptibility (ampicillin) was considered “optimizable”.
Results. Three were 106 cases of bacteraemia (2.2/1000 admitted patients; 84% E. faecalis); 83% had an underlying condition; 88% nosocomial or health related cases. Urinary infection was present in 20% and primary bacteraemia in 47%. High level resistance to gentamicin (HLRG) was present in 60%; there was no vancomycin or linezolid resistance. Most frequent empiric treatments were penicillin-betalactamase inhibitor (25%) and glycopeptides (22%). Most frequent definitive treatment was glycopeptides (34%), being “optimized” 21% and 44% of empiric and definitive treatments, respectively. Mortality was 23% (related, 14%). In the multivariate analysis, risk factors associated with HLRG were nosocomial acquired infection (OR 6.083; 95CI% 1.428-25.915) and no-abdominal origin (OR 6.006; 95CI%1.398-25.805). In multivariate analysis, independent risk factors for mortality were: Pitt > 3 (OR 14.405; 95CI%2.236-92.808) and active empiric treatment (OR 8.849; 95CI% 1.101-71.429).). Incidence in previous cohort was similar but HLRG rate has increased.
Conclusions. Risk factors associated with HLRG were nosocomial acquired infection and no-abdominal origin. Risk factors for mortality were initial clinical severity and having received active empiric treatment. HLRG rate has increased.

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Rev Esp Quimioter 2013:26(1):64-69

Treatment of invasive fungal infections in high risk hematological patients. The outcome with liposomal amphotericin B is not negatively affected by prior administration of mold-active azoles
                           

J. DE LA SERNA, I. JARQUE, J.LÓPEZ-JIMÉNEZ,  J.M. FERNÁNDEZ-NAVARRO, V. GÓMEZ, M. JURADO, A. PASCUAL, J. SERRANO, M. ROMERO, C. VALLEJO                         

There are concerns of a reduced effect of liposomal amphotericin B (L-AmB) given sequentially after mold-active azoles due to a possible antagonism in their antifungal mechanism. To investigate this possible effect in the clinic, we retrospectively studied 182 high risk hematologic patients with invasive fungal infections (IFI) who were treated with L-AmB. Overall, 96 patients (52.7%) had possible, 52 (28.6%) probable and 34 (18.7%) proven IFI according to EORTC classification. Most had suspected or proven invasive aspergillosis. We compared patients with prior exposure to mold-active azoles (n=100) to those having not (n=82). The group with prior mold-active azoles included more patients with poor risk features for IFI as acute myeloid leukemia (p<0.05) and prolonged neutropenia (p<0.05). A favorable response in the IFI, defined as a complete or partial response, was achieved in 75% and 74.4% of patients in the whole cohort, and in 66% and 74.4% of patients with probable or proven IFI in the two groups. None of these differences were significant. Multivariate analysis showed that refractory baseline disease and renal dysfunction were adverse factors for response in the IFI (p<0.05). Survival was poorer for patients with prior broad spectrum azoles (p<0.05), and for those who did not recover from neutropenia (p<0.05). In conclusion, the effectiveness of treatment of breakthrough fungal infection with L-AmB is not likely to be affected by prior exposure to mold-active azoles prophylaxis, but survival largely depends on host and disease factors.

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Rev Esp Quimioter 2013:26(3):214-220

Structural dynamics of Legionella pneumophila and Legionella bozemanii colony/biofilm                                
 

MARÍA LUISA GÓMEZ-LUS, MARÍA TERESA CORCUERA, RAFAEL GÓMEZ-LUS, CLAUDIA SÁNCHEZ-SERRANO,
FERNANDO GÓMEZ-AGUADO, MARÍA JOSÉ ALONSO, JOSÉ PRIETO
             

Objectives. The genus Legionella includes very pleomorphic species responsible for disease outbreaks in humans. The appearance of such has great importance to develop artificial biofilms in aquatic ecosystems. The aim of this work was to study the dynamics of growth and evolution of the internal structure of colonies of representative species of the genus as static biofilm model.
Methods. Isolated colonies of Legionella pneumophila and Legionella bozemanii grown in specific media for three and fifteen days were processed for histological methods and embedded in paraffin and epoxy resin for analysis by light microscopy, electron microscopy and image analysis.
Results. In colonies of both species were observed and defined specific architectural patterns, based on stratification and evolve over time. The strata differ in the amount of extracellular matrix, the morphology and population density and the proportion of dead cells. The internal structure of three days colonies showed large differences between L. pneumophila (two layers) and L. bozemanii (four layers). However, in the fifteen days colonies of both species evolved towards a common unique pattern formed by three layers. In both species the growth was also found within the culture medium, although this phenomenon was more intense in L. bozemanii with unique, central and larger invasions.
Conclusions. Our results demonstrate that Legionella colonies on solid culture media are a good model of static biofilm with a complex structural dynamics characterized by the presence of morphological and functional subpopulations. We bring here an histological approach model, allowing, in further research, detailed studies in evolutionary adaptations in multicellular communities to adverse media and to antimicrobials in Legionella species of clinical interest.

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Rev Esp Quimioter 2013:26(2):81-91

Mathematical modelling of the propagation of infectious diseases: Where we came from, and where we are going                                 
 

MARIA JOSÉ FRESNADILLO-MARTÍNEZ, ENRIQUE GARCÍA-SÁNCHEZ, ENRIQUE GARCÍA-MERINO, ÁNGEL MARTÍN DEL REY, JOSÉ ELÍAS GARCÍA-SÁNCHEZ               

This work deals with the study of the use of mathematical models to simulate the spreading of infectious diseases. There is no doubt about the importance of the use of computational tools that allow the health staff to model and predict the spreading of an infectious disease. Using such tools one can establish and simulate disease control strategies. The development of such technologies is a multidisciplinary issue; in this sense, the mathematical algorithms –that must be computationally implemented- play a central role. The main goal of this work is to highlight among health community the increasing importance of the use of mathematical models for epidemic disease spreading. Consequently, the main features of such models are introduced and their classification is stated taking into account the behavior, the basic population unit or the mathematical objects used. An exhaustive search of related papers through the most important databases (Medline and Web of Science) are performed. The main conclusion obtained from this work is the central role that mathematical models can play in the simulation of epidemic spreading; moreover, some ideas about the future research are stated.

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Rev Esp Quimioter 2013:26(3):221-225

Protection of Enterococcus faecalis in mixed cultures with carbapenemase-producing Escherichia coli and Bacteroides fragilis: effect of the bacterial load                                 
 

DAVID SEVILLANO, LORENZO AGUILAR, LUIS ALOU, MARÍA-JOSÉ GIMÉNEZ, FABIO CAFINI, NATALIA GONZÁLEZ, JOSÉ PRIETO             

Introduction. This study explores effects of pH and inoculum size on imipenem versus tigecycline activity against E. coli, B. fragilis and E. faecalis, both in individual and mixed cultures.
Methods. MIC/MBCs (mg/L) of tigecycline and imipenem were 0.12/≥16 and 4/4 for E. coli, 0.12/0.5 and ≥16/≥16 for B. fragilis, and 0.12/≥16 and 2/≥16 for E. faecalis, respectively. Killing curves in supplemented Brucella broth were performed at pH 7 or 5.8, with two final inocula (≈105 or ≈107 cfu/ml) of each isolate (individual cultures) and with 1:1:1 mixed inocula. Tubes were 48h incubated at 37ºC in anaerobiosis. Final concentrations (estimated concentrations in colon) were 1.50 mg/L for tigecycline and 26.40 mg/L for imipenem, with antibiotic-free curves as controls. Experiments were performed in triplicate.
Results. Imipenem showed inoculum effect against E.coli and B. fragilis, with reductions in initial inocula in experiments with standard inocula contrasting with increases in experiments with high inocula (both individual and mixed cultures). Against E. faecalis no inoculum effect for imipenem was observed in individual cultures, with marked reductions in initial inocula regardless inoculum size. However in mixed experiments the indirect protection of E. faecalis by the two gramnegatives resulted in bacterial regrowth. This protection was inoculum-dependant since it occurred with high but not with standard inocula. Tigecycline reduced initial inocula of the three isolates regardless culture type (individual/mixed) or experimental conditions (pH/inocula size), with lower reductions for the tolerant E. faecalis.
Conclusion. Carbapenemase activity was inoculum-dependant for self-protection and indirect protection of E. faecalis.

Rev Esp Quimioter 2013:26(3):221-225 [pdf]

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