Rev Esp Quimioter 2011:24(4):213-216

Antimicrobial sensitivity of hippurate-negative Campylobacter and Helicobacter pullorum strains isolated from patients with diarrhea          


P. BASCUÑANA, I. PENA, J. J. PICAZO, A. C. VELASCO                

C. jejuni as well as some hippurate-negative Campylobacter species and related diarrheagenic organisms, are the leading cause of gastroenteritis in our environment all throughout the year. The aim of the present study was to determine the sensitivity of hippurate-negative Campylobacter and Helicobacter pullorum strains isolated from the stools of patients with diarrhea. We tested 39 Campylobacter coli, two C. lari and five Helicobacter pullorum strains identified by mass spectrometry analysis. The sensitivity to amoxicillin-clavulanic acid, erytrhomycin, azithromycin, gentamicin, ciprofloxacin, levofloxacin, tetracycline, tigecycline and chloramphenicol was tested by E-test. Most hippurate-negative Campylobacter and H. pullorum isolates studied showed high resistance to tetracycline and to the two fluorquinolones tested. On the other side, all strains were sensitive to amoxicillin-clavulanic acid, tigecycline and chloramphenicol, while most of them were sensitive to both macrolides tested and to gentamicin. 

 
Rev Esp Quimioter 2011:24(4):213-216 [pdf]

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Rev Esp Quimioter 2012:25(2):89-99


Emergence of plasmid mediated AmpC β-lactamasas: Origin, importance, detection and therapeutical options 
                 
C. SERAL, M. J GUDE, F. J. CASTILLO                                                            

 
AmpC β-lactamases can hydrolyze penicillins, oxyimino-, 7-α-methoxycephalosporins and monobactams. Susceptibility to cefepime or cefpirome is little affected and is unchanged for carbapenems. Originally such genes are thought to have been mobilized to mobile genetic elements from the chromosomal ampC genes from members of Enterobacteriaceae facilitating their spread and now they can appear in bacterial lacking or poorly expressing a chromosomal ampC gene. The prevalence of infection by plasmid mediated AmpC (pAmpC) varies depending on the type of enzyme and geographical location and blaCMY-2 is the most frequently detected worldwide. Typically, pAmpC producing isolates are associated with resistance to multiple antibiotics making the selection of an effective antibiotic difficult. Phenotypic and molecular methods to detect pAmpC are described and the role of different antibiotics in the treatment of these infections is examined. Surveillance studies about the evolution of this emerging resistant mechanism are important in clinical isolates. Evaluate the in vitro susceptibility of these isolates and the clinical efficacy of other therapeutic options is required.
   

Rev Esp Quimioter 2012:25(2):89-99 [pdf]

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Rev Esp Quimioter 2012:25(4):240-244

Echinocandins: searching for differences. The example of their use in patients requiring continuous renal replacement therapy                   

N. DE LA LLAMA-CELIS, R. HUARTE-LACUNZA, C. GÓMEZ-BARAZA, I CAÑAMARES-ORBIS, M. SEBASTIÁN- ALDEANUEVA, R. ARRIETA-NAVARRO                                                                            

The echinocandins have a growing role in the treatment of fungal infections because of their novel mechanism of action. This is reflected in recently published management guidelines, but available in vitro data, animal studies, and clinical studies do not clearly differentiate the three agents in class. Comparative clinical efficacy among agents within the class, pharmacokinetic profiles in special populations, pharmacoeconomics justifications, and place in therapy have been largely unanswered. They share many common properties but marketing strategies of drug manufacturers are engaged in product differentiation. Although exist similarities in the pharmacokinetic (PK) profiles of the echinocandins, limited data have been published regarding their pharmacokinetics in continuous renal replacement therapy (CRRT) patients. The pharmacokinetics of drug removal in critically ill patients receiving CRRT is very complex, with multiple variables affecting clearance. This review outlines the basic principles that determine whether a dose adjustment is required. Two studies with data on PK parameters of micafungin and anidulafungin in CRRT patients have been published and are compared following that basic principles in the review.

 

Rev Esp Quimioter 2012:25(4):240-244 [pdf]

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Rev Esp Quimioter 2010:23(2):76-80

Variability in the sensitivity to tigecycline against Acinetobacter baumannii in different culture medium

A. TENORIO-ABREU, J. M. EIROS, E. RODRÍGUEZ-MOLINS, D. ANDALUZ, F. BOBILLO, M. DOMÍNGUEZ-GIL, R. ORTIZ DE LEJARAZU 

 

Introduction. The tigecycline may represent a therapeutic alternative for the control of multiresistant A. baumannii, although there is no consensus regarding the cutoff points for sensitivity or variability of MIC as a function of culture medium used for the antibiogram against this microorganism. Therefore, our objective was to verify this variability, and propose the culture medium that comes closest to the standard method.
Methods. We selected 41 strains of carbapenem-resistant A. baumannii. We analyzed the sensitivity to tigecycline in different culture medium: Mueller Hinton agar Oxoid commercial (C-MH), Mueller Hinton fresh agar BD and Co., USA (F-MH) and ISO-sensitest fresh agar Oxoid, using the E-test and disk. The MICs were compared against those obtained using the technique standard of macrodilution.
Results. The mean MIC and inhibition diameters obtained in the different culture medium corresponded to 9.26 mg/L and 15.1 mm in diameter for MH-C, 1.71 mg/L and 22.7 mm for MH-F; 2.68 mg/L and 20.8 mm for ISO-sensitest. Half the MIC obtained by the standard method of dilution was 0.47 mg/L (SD = 0.21), with values between 0.25 and 1 mg/L.
Conclusion. In the three growth media studied, MICs superior to the standard are observed, which is false to interpret resistance in many cases. However, the medium that comes closer more that of reference is the MH-F.

 
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Rev Esp Quimioter 2010:23(4):196-200

Antibiotic susceptibility of Corynebacterium macginleyi strains causing conjunctivitis   

M. ESPÍNOLA, Á. SOMODEVILLA, D. DOMINGO, T. ALARCÓN, M. LÓPEZ-BREA    

 

Introduction. Lipophilic corynebacteria are part of the saprophytic skin flora and they rarely cause infection. C.macginleyi is an exception since it has been involved in conjunctivitis and other ocular surface affections.

Material and methods. Thirty three C. macginleyi strainswere obtained from conjunctival swabs from patients with conjunctivitis symptoms. The minimum inhibitoryconcentration (MIC) for 7 antibiotics (penicillin, gentamycin,ciprofloxacin, tetracycline, vancomycin, rifampicin and linezolid) was tested by broth microdilution method.

Results. One strain was resistant to ciprofloxacin (MIC=16 mg/L) and two were resistant to tetracycline (MIC= 64 y 16mg/L). The rest of the strains were susceptible to all the antibiotics tested.

Conclusions. At the moment, C. macginleyi does not present a major problem due to the low resistance rates shown in the present and other studies. However, epidemiological surveillance of its susceptibility pattern is needed as well as an appropriate use of topical antibiotics in order to achieve a good infection control.    

 
Rev Esp Quimioter 2010:23(4):196-200 [pdf]

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Rev Esp Quimioter 2011:24(2):107-111

Methicillin-resistant Staphylococcus aureus: changes in the susceptibility pattern to daptomycin during a 10-year period (2001-2010)  

J. J. PICAZO, C. BETRIU, E. CULEBRAS, I. RODRÍGUEZ-AVIAL, M. GÓMEZ, F. LÓPEZ-FABAL AND VIRA GROUP           

 

Introduction. The objective of this study was to evaluate the activity of daptomycin and other agents against methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from 2001 to 2010, in order to determine changes and to detect resistance trends.
Methods. The study included a total of 1,130 MRSA isolates collected as part of a multicenter surveillance program for antibiotic resistance, Estudio de Vigilancia de Resistencia a los Antimicrobianos (VIRA study), from 51 medical centers throughout Spain between 2001 and 2010. Broth microdilution test was performed according to the Clinical Laboratory Standards Institute guidelines.
Results. Daptomycin showed excellent activity and maintained its activity over time; only one MRSA isolate collected in 2001 was nonsusceptible to this agent (MIC=2 mg/L). Based on the MIC90, daptomycin was 2-4 dilutions more active than vancomycin, teicoplanin and linezolid. Daptomycin retained activity against MRSA isolates that were resistant to linezolid, to quinupristin-dalfopristin, or showed intermediate susceptibility to vancomycin.
Conclusions. Our data and those of other studies, coupled with daptomycin’s rapid bactericidal activity, suggest that this antimicrobial could be an alternative in the treatment of severe infections caused by multiresistant S. aureus.

 
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Rev Esp Quimioter 2011:24(4):217-222

Nosocomial infection following video-assisted thoracoscopic surgery           


D. N. NAN, M. FERNÁNDEZ-AYALA, C. FARIÑAS-ÁLVAREZ, R. MONS, J. GONZÁLEZ-MACÍAS, M. C. FARIÑAS                  

Objectives: To assess the incidence and risk factors for nosocomial infection after video-assisted thoracic surgery (VATS).
Methods: Prospective cohort study of all consecutive patients who underwent VATS surgery during 20 months. Patients were visited on a daily basis and followed up until they were discharged from the hospital
Results: During the study period 217 patients (70.1% men; mean age, 50.9 years, range 15-85 years) underwent VATS. Fourteen (6%) episodes of postoperative infection were diagnosed in 13 patients, including pneumonia (n = 2), lower respiratory tract infection (n = 9), surgical site infection (n = 2), and urinary tract infection (n = 1). Prior inmunosupresion (adjusted odds ratio [OR], 2.70; 95% confidence interval [CI], 1.52-4.84), prior infections (OR, 14.9; 95% CI 1.91-116.5), preoperative stay > 2 days (OR, 3.37; 95% CI 1.00-11.40), neoplasia (OR, 3.69; 95% CI, 1.94-7.06) duration of surgery > 45 minutes (OR, 5.91; 95% CI, 1.00-36.40) and presence of central venous catheter (OR, 16.40; 95% CI, 2.29-117.20), were independent risk factors for nosocomial infection.
Conclusions: Nosocomial infection rate after VATS was low. Respiratory infection was the most common infection. Factors which affect patient immunity, preoperative stay and perioperative-related variables were independently associated with infection. 

 
Rev Esp Quimioter 2011:24(4):217-222 [pdf]

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Rev Esp Quimioter 2012:25(2):100-121

Antibiotheraphy in the 21st century, antibacterials for the second decade. Posibilities or realities in the future? 
           
J. E. GARCÍA-SÁNCHEZ, E. GARCÍA-MERINO, Á.  MARTÍN-DEL-REY, E. GARCÍA-SÁNCHEZ                                                             

 
A review of some antibacterial products is done motivated by the serious situation arisen by the antimicrobial resistance in bacteria. The attention is focus on those drugs with suitable antimicrobial properties that have prospects to be commercialized in the next years because of they are undergoing a clinical development phase (I, II, III). The search for these antibacterial products has been done by an exhaustive study of conference proceedings and web pages of international congresses on chemotherapy, infectious diseases and new antimicrobial drugs. Some of the new antibacterial products acts on known targets, and they belong to already used families. Furthermore, the great majority acts against the gram-positive bacterium. There is also some limited-spectrum antimicrobial drug whose use would minimize the adverse biological effects.
  

 

Rev Esp Quimioter 2012:25(2):100-121 [pdf]

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Rev Esp Quimioter 2012:25(4):245-251

Pharmacodynamic and pharmacokinetic evaluation of respiratory fluoroquinolones. Guideline to selection of the most appropriate fluoroquinolone                   

J. PARRA-RUIZ, J. HERNÁNDEZ-QUERO                                                                               


Since its approval, fluoroquinolones have become one of the most prescribed antibacterial agents. Because of its widespread use, serious concerns about the emergence of resistance in Streptococcus pneumoniae, Pseudomonas spp, and entrobacteriaceae, has arisen, especially because of cross-resistance between fluoroquinolones.
Huge efforts has been done to identify pharmacokinetic (PK) parameters like maximum serum concentration (Cmax), area under the curve of serum concentrations (AUC) and pharmacodynamic (PD) parameters like the minimum inhibitory concentration (MIC) or the mutant prevention concentration (MPC), to optimize the use of the new fluoroquinolones, especially against these difficult to treat microorganisms.
The new fluoroquinolones commercially available in Spain, levofloxacin and moxifloxacin, have significant differences in their PK (Cmax, half-life, volume of distribution, etc), PD (MIC, MPC,) and in their PK/PD parameters (AUC/MIC; AUC/MPC) that allow clinicians to establish clear preference for the utilization of one of them.
Proper use of these new fluoroquinolones according to these PK/PD parameters will result in better management of respiratory infections with a reduction in the emergence of resistance. Based on data reviewed in this paper moxifloxacin use, with best PK/PD characteristics, should be preferred over levofloxacin. Should levofloxacin be used, alternative dosing strategies would be recommended to avoid selection of resistant variants.  

 

Rev Esp Quimioter 2012:25(4):245-251 [pdf]

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Rev Esp Quimioter 2010:23(2):81-86

Activity of daptomycin, ciprofloxacin, clindamycin and cotrimoxazole against coagulase-negative Staphylococcus strains with diminished susceptibility to vancomycin

M. FAJARDO, R. HIDALGO, S. RODRÍGUEZ, E. GARDUNO, F. F. RODRÍGUEZ, M. ROBLES 

 

Introduction. Coagulase Negative Staphylococci (CNS) have become one of the most common nosocomial pathogens and it has a high mortality rate due to the increased of seriously ill patients survival, long states immunosuppression and presence of foreign bodies, such as catheters, prostheses, pacemakers, etc. In addition, there is a significant increase in resistance to antimicrobial drugs, especially beta-lactams, and the increase in the MIC for vancomycin leads to a loss of clinical efficacy. This necessitates the search for new therapeutic alternatives, such as daptomycin. The aim of this paper is to study the activity of daptomycin, ciprofloxacin, clindamycin and cotrimoxazole in two groups of clinically significant CNS. a MIC90 with vancomycin ≤ 1 mg/L and the other with MIC90 2 mg/L.
Methods. We identified and studied MIC90 to ciprofloxacin, clindamycin and cotrimoxazole from 54 strains of clinically significant by the CNS Combo 22 Microscan panels (Dade Behring, Siemens). The MIC90 for daptomycin was performed using Etest (AB BioMérieux, Solna, Sweden) on Mueller Hinton plates (BioMérieux, France).

Results. In Group I (vancomycin MIC90 ≤ 1 mg/L) were 19 strains whereas in Group II (vancomycin MIC90 = 2 mg/L) were 35 strains. Expressed in mg/L, MIC90 ranges for daptomycin were 0.047-0.5 in Group I and 0.064-0.5 in Group II. For ciprofloxacin were 8 sensitive strains and 11 resistant in Group I and 10 sensitive and 25 resistant in Group II. For clindamycin were 7 sensitive strains and 12 resistant in Group I and 16 sensitive and 19 resistant in Group II. Finally, for cotrimoxazole were 10 sensitive strains and 9 resistant in Group I and 19 sensitive and 16 resistant in Group II.
Conclusions. The MIC levels to daptomycin were not influenced by the increase in the MIC for vancomycin. There was no statistically significant difference for the sensitivity of ciprofloxacin between the two groups of vancomycin. Regardless of vancomycin, there were a clear relationship between the sensitivity of ciprofloxacin with clindamycin and cotrimoxazole.

 
Rev Esp Quimioter 2010:23(2):81-86 [pdf]

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