Rev Esp Quimioter 2012:25(3):172-179

Matematical modeling of antibiotic resistance. Perspectives from a meta-analysys                 

M. J. FRESNADILLO-MARTÍNEZ, E. GARCÍA-SÁNCHEZ, E. GARCÍA-MERINO, Á. MARTÍN-DEL-REY, Á. RODRÍGUEZ-ENCINAS, G. RODRÍGUEZ-SÁNCHEZ, J. E. GARCÍA-SÁNCHEZ                                                                         

 
The antibiotic resistance is one of the greatest challenges of the international health community. The study of antibiotic resistance must be a multidisciplinary task and, in this sense, the main goal of this work is to analyze the role that Mathematical Modeling can play in this scenario. A qualitative and cuantitative analysis of the works published in the scientific literature is done by means of a search in the most important databases: MEDLINE, SCOPUS and ISI Web of Science. Consequently, there are few papers related to our topic but the existing works have been published in high-quality and impact international journals. Moreover, we can state that mathematical models are a very important and useful tool to analyze and study both the treatments protocols for resistance prevention and the assesment of control strategies in hospital environtment, or the prediction of the evolution of diseases due to resistant strains.

 

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Rev Esp Quimioter 2012:25(4):283-292

Pharmacoeconomic analysis of the treatment of methicillin-resistant Staphylococcus aureus with daptomycin or vancomycin                     

C. RUBIO-TERRÉS, D. RUBIO-RODRÍGUEZ, N. MAJOS, S. GRAU                                                                                   


Introduction. The increased morbidity, mortality and high costs associated with bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) is a major public health problem. Pharmacoeconomic analysis was performed to compare the efficiency of daptomycin (DAP) against vancomycin (VAN) in the treatment of this infection.
Methods. Retrospective, deterministic and probabilistic cost-effectiveness analysis. The effectiveness of the treatments was estimated from the results of a randomized clinical trial, which compared DAP (6 mg / kg IV daily) and VAN (1 g IV every 12 hours), both with or without gentamicin (1 mg / kg IV every 8 hours). Resource utilization was estimated from the clinical trial of the drug datasheets and Spanish sources, the unit costs were obtained also from Spanish sources. Monte Carlo probabilistic analysis and deterministic analysis were performed.
Results. The clinical trial cure rates were higher with DAP (44.4%, 95% CI 43.5 to 45.4%) than with VAN (31.8%, 95% CI 30.9 to 32.7%) not statistically significant (p = 0.2203) but with economic impact. With DAP would occur less costs due to treatment failure (rescue antibiotics, additional tests, prolonged hospital stay and adverse reactions) than with VAN. In the base case the average cost of disease per patient was € 12,329 to € 12,696 with DAP and VAN (difference of 367 €). DAP treatment was dominant (more effective, with lower costs than VAN) both in the deterministic and probabilistic analysis. In the Monte Carlo simulation, DAP was the most cost-effective treatment in 100% of the 10,000 simulations, for a willingness to pay € 12,000 per additional cure (approximate cost of MRSA bacteraemia episode).
Conclusions. According to this model, daptomycin is more cost-effective than vancomycin in treating MRSA bacteremia. The higher cost of acquisition of daptomycin does not imply a higher cost of treating this infection.  

 

Rev Esp Quimioter 2012:25(4):283-292 [pdf]

 

 

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Rev Esp Quimioter 2012:25(1):31-36

Respiratory infections: etiology and patterns of resistance in the hospital general of Ciudad Real                

 

 

I. CLEMENTE, M. D. MAÑAS, J. MARTÍNEZ, C. MONROY, M. SIDAHI, J. YANES                             

 

 

Objectives. Understanding the impact on our work place of increasing antibiotic resistance in respiratory infections.
Material and methods. We have performed a retrospective observational study on patients with significant sputum culture admitted to Internal Medicine Service Hospital General in Ciudad Real from January to December 2008. Information has been collected on the epidemiological, microbiological features, resistance patterns and treatment.
Results. The total number of patients included in this study was 60. In 83.3% there was a predisposing factor. In 43 cases the diagnosis was made in spring and summer months. The exacerbation of COPD was the most frequent diagnosis (61.7%). The most frequently isolated organism was Pseudomonas spp. (41.7%). In our hospital the most commonly used antimicrobials in the initial treatment are levofloxacin (36.7%) and amoxicillinclavulanate (26.7%). The antibiotics with the highest percentage of antibiotic resistance were ciprofloxacin in E. coli (66.7%) and Pseudomonas spp. (60%), penicillin for S. pneumoniae (100%).
Conclusions. The results of this study demonstrate the significant presence of resistance to most commonly used antibiotics in microorganisms which cause respiratory infections. 

 

 
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Rev Esp Quimioter 2012:25(3):180-182

Investigation of antimicrobial resistance to Enterococcus faecium                 

M. M. CASAL, M. CAUSSE, F. SOLÍS, F. RODRÍGUEZ-LÓPEZ, M. CASAL                                                                         

 
We performed a antibiotic resistance study on Enterococcus faecium isolated from intrahospitalary and extrahospitalary samples between 2004 and 2010. Three different samples were studied; urine, blood and wound swabs, considering a strain per patient. We included in the study a global amount of 637 E. faecium isolares. We employed semiautomatic system WIDER I for identification and sensitivity testing. We considered susceptibility and resistance criteria recommended by MENSURA group.We found a susceptibility rate of 48.05% to betalactams, 100% to linezolid, and 99.46% to vancomycin. The resistance to aminoglycosides ranged between 41.41 and 73.55%. We obtained 6 isolates resistant to vancomycin one of them from an extrahospitalary strain and five from intrahospitalary strains. It seems that vancomycin resistance should be controlled.

 

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Rev Esp Quimioter 2012:25(4):299-304

Antifungal prophylaxis in the haematological patient: a practical approach                     

L. VÁZQUEZ, E. CARRERAS, D. SERRANO, I. JARQUE, J. MENSA, J. BARBERÁN                                                                                   


Antifungal prophylaxis in the haematological patient is currently regarded as the gold standard in situations with a high risk of infection, such as acute leukaemias, myelodysplastic syndromes and autologous or allogenic hematopoietic stem cell transplantation. Over the years, different scientific societies have established a series of recommendations on antifungal prophylaxis based on prospective studies performed with different drugs. However, the prescription of each one of the agents must be personalised, adapted to the characteristics of each patient and to possible interactions with concomitant medication.  

 

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Rev Esp Quimioter 2012:25(1):37-41

Antimicrobial resistance in clinical patterns of Pseudomonas aeruginosa                

M. M. CASAL, M. CAUSSE, F. RODRÍGUEZ-LÓPEZ, M. CASAL                              

 

Pseudomonas aeruginosa is an opportunistic microorganism that is frequently the cause of nosocomial infections. Multiple mechanisms are involved in its natural and acquired resistance to many of the antimicrobial agents commonly used in clinical practice. We performed an antibiotic resistance study on P. aeruginosa isolated from intrahospitalary and extrahospitalary samples between 2005 and 2010 years. We included in the study a global amount of 3,029 P. aeruginosa isolates from clinical samples received at University Hospital Reina Sofia. Microbiology Service in Córdoba (Spain). Semiautomatic system WIDER I for strains identification and sensibility testing was employed. We considered susceptibility and resistance criteria recommended by MENSURA group. Results of the analysis showed that P. aeruginosa maintanied similar levels of antimicrobial susceptibility during the period 2005-2010, with increased susceptibility to amikacin, gentamicin and cefalosporins. Therewere also important differences in the degree of susceptibility between intrahospital and extrahospital strains during 2010 year, except for tobramicin and fosfomycin. The intrahospital difference in susceptibility was also evaluated, emphasizing the importance of periodically surveillance of susceptibility and resistance patterns of P. aeruginosa, in each setting in order to evaluate different therapeutic guidelines, because it is not always advisable to extrapolate data from different
regions. 

 
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Rev Esp Quimioter 2012:25(3):183-188

Antimicrobial resistance of the most frequently isolated microorganisms in the Hospital General La Mancha Centro between June 2009 and May 2010                 

M. A. ASENCIO, R. CARRANZA, M. HUERTAS                                                                           

 
Introduction: During the last two decades an increased incidence of infections caused by multiresistant bacteria has been observed. The spread of these microorganisms in the hospital is a major therapeutic and epidemiological problem. The aim of this study was to determine local resistance patterns of microorganisms causative of multirresistant infections in patients admitted to our hospital.
Methods: A retrospective study was designed, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from clinical and surveillance samples of patients admitted to the Hospital General La Mancha Centro, between June 2009 and May 2010.
Results: The rate of S. aureus isolates resistant to oxacillin was 50%, with 0% resistance to vancomycin. The percentage of resistance to 3rd generation cephalosporins in E. coli and K. pneumoniae was 17 and 19%, respectively; the ESBL-production in enterobacterial strains was 15 and 19%, respectively, and the quinolone resistance was 41 and 28%, respectively. The resistance of P. aeruginosa to ceftazidime and imipenem was 30 and 40%, respectively. Most strains of A. baumannii studied came from a single multidrug-resistant clone, endemic in the ICU of our hospital.
Conclusions: Of particular concern is the high rate of MRSA, E. coli and K. pneumoniae ESBL producers and resistant to fluoroquinolones as well as P. aeruginosa multiresistant. A. baumannii isolates belong mainly to endemic multidrug-resistant clone from the ICU.

 

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