Antibiotic prescribing to the paediatric population of Castilla y León in the last decade: trends, seasonal fluctuations and geographical differences            

M. E. VÁZQUEZ, J. M. EIROS, F. MARTÍN, S. GARCÍA, R. M. BACHILLER, M. J. VÁZQUEZ                                                                   

 
Introduction. The development of antibiotic resistance is a danger to the health of the population, especially for children, due to low antimicrobial arsenal available to them.
Material and methods. We performed a retrospective observational study referred to the prescriptions of systemic antibiotic in the paediatric population of Castilla y León in the years 2001 to 2010.
Results. The total use of antibiotics outside hospitals is around to 20.7 DID (defined daily dose per 1,000 inhabitants per day). There are two different phases: the first from 2001 to 2007 where there is an increase of consumption, with a peak of 25 DID in 2003, following a phase of decline, with a minimum of 18 DID in 2010. Broad-spectrum penicillins are the most used. We also observe changes in prescription trends. It has a clear seasonal prescription profile related to acute respiratory infections (ARI) of winter, stands in February. The use of antibiotics varies substantially between different Health Areas.
Conclusions. We observed a decrease in antibiotic prescription to children in the last three years. Changes in the prescription profile for amoxicillin and at the expense of greater spectrum antibacterial antibiotics indicate a better match to therapeutic guidelines in recent years. The variability found in different Health Areas suggests the need for improvement in the rational use of antibiotic, at least to some.
 

Rev Esp Quimioter 2012:25(2):139-146 [pdf]

Colonial architecture and growth dynamics of Staphylococcus aureus resistant to methicillin

F. GÓMEZ-AGUDO, M. L. GÓMEZ-LUS, M. T. CORCUERA, L. ALOU, M. J. ALONSO, D. SEVILLANO, D. VAL, A. PALMEIRO, N. IGLESIAS, J. PRIETO

The aim of the study was to explore the structure and growth dynamics of Staphylococcus aureus resistant to methicillin (MRSA) colonies using semithin sections visualized by light microscope. One S. aureus susceptible to methicillin (MSSA) and one MRSA clinical strains were studied. Colonies in agar plates were embedded in epoxy resin after each incubation period (24 h and 48 h) at 37ºC. Semithin sections of 0.5µm were stained with toluidine blue and visualized by light microscope. Microscopically, no structural differences were observed between SASM and SARM colonies but differences were observed in both strains between 24 and 48 h incubation periods. Colonies showed two layers clearly differentiated at24 h independently of the resistance to methicillin: (A) one basal layer with high density of population in contact with culture media, and (B) one superficial layer with a lower density of population. Colonies showed four layers at 48 h:(A) one basal layer with high density of population; (B) one clear layer constituted by very degraded bacterial remains in which can be observed cocci dispersed with their dyeing properties; (C) one mixed layer constituted by viable bacteria and little degraded bacterial remains (D) one superficial layer with a lower density of population than basal layer. Colonial architecture is a complex and time-dependent process.

 
Rev Esp Quimioter 2009:22(4):224-227 [pdf]

Predictive factors of 2009 H1N1 virus infection in patients with influenza syndrome

A. SUPERVÍA, F. DEL BAÑO, G. MALDONADO, O. PALLÀS, A. AGUIRRE, C. VILAPLANA, J. P. HORCAJADA, M. T. MARTÍNEZ-IZQUIERDO    

Introduction: Polymerase chain reaction (PCR) testing isone of the better techniques for viral detection in nasopharyngeal swabs. The objective of this study was to assess the percentage of positive swabs and to determine whether there were differences according to PCR positivity.
Material and Methods: A retrospective study of 362 patients with flu syndrome attended at the Emergency Department between July 15 and December 15, 2009, in whom PCR of nasopharyngeal swabs for the detection of H1N1 2009 influenza virus was performed.  Those cases in which swab testing was adequately requested were identified, and patients were divided into two groups according to positive or negative results for H1N1 2009 influenza virus.
Results: Nasopharyngeal swab was inadequately ordered in 87. In the remaining 275 patients, PCR was positive in 141. Patients with positive nasopharyngeal swabs were younger (mean [SD] age 36.1 [15] vs42.3 [18] years, P= 0.002), had lower white blood cell, neutrophil and lymphocyte counts, lower serum concentrations of C-reactive protein (5.15 [5] vs 10.5[12] mg/dL, P= 0.036) and lower incidence of radiological infiltrates (20.5% vs 33%, P= 0.036). In the logistic regression analysis, age, serum C-reactive protein levels, and lymphocyte count were independently associated with a positive nasopharyngeal swab.
Conclusions: About 50% of patients with flu syndrome had positive nasopharyngeal swabs for H1N1 2009 influenza virus. Age, C-reactive protein, and lymphocyte count were independent predictors of positivity.    

Rev Esp Quimioter 2011:24(1):25-31 [pdf]

Macrolides and staphylococcal biofilms                

J. PARRA-RUIZ, C. VIDAILLAC, M. J. RYBAK                            

Medical device-associated infections represent a growing problem with limited or no therapeutic options beyond implant removal. Bacterial biofilm is the major and the final determinant of the poor prognosis of these difficult-to-treat infections. Due to the high antimicrobial resistance level of bacteria organized in biofilms, combination therapy is most often recommended, and macrolides may represent antibiotics of choice. Their anti-biofilm activity has been successfully used in-vitro and in-vivo against biofilm-associated infections caused by Pseudomonas aeruginosa and other Gram-negative bacilli. However there is only little data regarding their clinical interest against infections involving staphylococcal biofilms. Despite controversial reports, there is growing in-vitro and in-vivo evidences of anti-staphylococcal biofilm activity of macrolides that could represent a significant advance in the battle against implant-related infections. 

 
Rev Esp Quimioter 2012:25(1):10-16 [pdf]

Discrepancy in the disk diffusion susceptibility test of Pseudomonas aeruginosa strains isolated from cystic fibrosis patients after anaerobic preincubation and its potential clinical relevance                    

F. CAFINI, C. GARCÍA REY, P. BAS, M. L. GÓMEZ-LUS, I. SÁNCHEZ, S. VÁZQUEZ, J. PRIETO                                                                                   

Introduction. In cystic fibrosis, the Pseudomonas aeruginosa cells grow inside the thick mucus layer. In spite of being an obligate aerobe, P. aeruginosa is able to grow in a limited oxygen environment. Bacterial cells could be suddenly exposed to high oxygen levels due to the movements of the mucus mass. The aim of study was to determine the impact of a previous anaerobic incubation on the antimicrobial susceptibility of P. aeruginosa strains isolated from patients with cystic fibrosis.
Materials and Methods. Four P. aeruginosa strains were used in this study (ATCC 23389 and 3 clinical isolates). The disk diffusion method was used to determine the antimicrobial susceptibility.
Results. The anaerobic pre-incubation produced changes on the susceptibility in all studied strains. All susceptible strains after an aerobic incubation remained susceptible after an anaerobic incubation except one clinical strain, which became resistant to betalactams. The response was strain-dependent and the most significant increase in susceptibility was observed in two of the three clinical isolates when ciprofloxacin was used.
Conclusions. The antimicrobial susceptibility of P. aeruginosa strains varies after their exposure to anaerobic conditions. Treatments promoting mucus fluidization could contribute to increase the antimicrobial efficacy.  

Rev Esp Quimioter 2012:25(4):269-273 [pdf]