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

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]

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Rev Esp Quimioter 2010:23(3):109-114

Treatment of human infections caused by Bartonella spp. 

L. PÉREZ-MARTÍNEZ, J. R. BLANCO, J. A. OTEO 

 

Infections by Bartonella spp. include a wide spectrum of emerging and re-emerging infectious diseases.There is not a universal therapy for this infection, therefore treatment should be chosen individually. The aim of this review is to update the therapeutics aspects of this kind of infections.

 
Rev Esp Quimioter 2010:23(3):109-114 [pdf]

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

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]

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Rev Esp Quimioter 2011:24(3):131-135

Rapid identification and susceptibility testing of Gram-positive cocci in BacT/ALERT blood cultures by direct inoculation into the Vitek 2 system       

A. BARREALES, M. LARA, I. HERNÁNDEZ, Ó. DÍEZ           

 

Introduction: To provide the clinician with early information about blood culture results allows a better prognosis and a reduced mortality rate of the patient with sepsis. In order to contribute to this aim, we performed a study for the identification and susceptibility profiling of positive blood cultures by direct inoculation into the automated Vitek 2 system.
Materials and Methods: Blood cultures of 57 patients with monomicrobial bacteriaemia due to gram-positive cocci
were evaluated. Addition of saponin to the fluid from blood culture bottles was performed prior to the inoculation of Vitek 2 system cards. The same samples were also examined with the standard method starting from agar plate grown subcultures.
Results: Comparison between the results obtained with the standard method and the direct method revealed that 82% of the samples were correctly identified and that 97% of the isolates showed a concordant antimicrobial susceptibility profile for all drugs tested. Compared to the standard method, the very major error rate of the direct method was just 0.5%, the major error rate was 0.5%, and the minor error rate was 2%.
Conclusion: These data suggest that addition of saponin to the fluid from blood culture bottles of the BacT/ALERT® 3D before inoculation of the appropriate Vitek 2 cards leads to the rapid and reliable identification and susceptibility profiling of gram-positive cocci in blood samples. Compared to the standard method, the direct method would reduce turnaround time by at least 24 hours.

 
Rev Esp Quimioter 2011:24(3):131-135 [pdf]

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Rev Esp Quimioter 2012:25(1):4-9

Invasive fungal infection in critically ill patient: role of micafungin                

M. NIETO, E. ESCUDERO                         

The invasive fungal infections (IFIs) have increased in critically ill patients in recent years and are a serious complication that determine the evolution and prognosis of critically ill patients, especially invasive candidiasis (IC) and candidemia. Fortunately, treatment options for these infections have increased and there is a large arsenal of antifungal agents. This review of the literature, using PubMed and Cochrane databases, assesses the situation of the IFIs in critically ill patients and discusses the role of micafungin in this context. The broader spectrum of this candin, which gets the antifungal effect with lower MICs and that translates into greater clinical efficacy with a lower rate of adverse effects and easier to use, with proven cost-effectiveness compared with other antifungal, position micafungin as a useful therapeutic option for the management of invasive candidiasis / candidemia in critically ill patients. 

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

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]

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

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]

 

 

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Rev Esp Quimioter 2010:23(3):115-121

Endotoxin adsortion as adjuvant therapy in gramnegative severe sepsis 

F.J. CANDEL, F. MARTÍNEZ-SAGASTI, M. BORGES, E. MASEDA, M. HERRERA-GUTIÉRREZ, J. GARNACHO-MONTERO, F.J. MAYNAR, R. ZARAGOZA, J. MENSA, J.R. AZANZA 

 

The mortality rate of severe sepsis and septic shock remains still high. Within the last years a better knowledge of its physiopathology and the implementation of a group of measures addressed to a fast identification and early treatment of the septic patients have proved to reduce mortality rate. Likewise, it continues being investigated in modulating the inflammatory response and limiting the harmful action of the bacterial products on the immune system. As a result of this research some endotoxin adsorber devices have been designed to control one of the most important targets that start the inflammatory cascade when gramnegative microorganisms are involved.The usefulness that these endotoxin removal devices might have as adjuvant treatment in the Septic Syndrome and its applicability are reviewed in this paper. Likewise a profile of patient that might be to the benefit of this therapy is suggested according to the current knowledge.  

 
Rev Esp Quimioter 2010:23(3):115-121 [pdf]

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Rev Esp Quimioter 2011:24(1):32-36

Rapid detection of clarithromycin resistant Helicobacter pylori strains in Spanish patients by polymerase chain reaction-restriction fragment length polymorphism 

S. AGUDO, G. PÉREZ-PÉREZ, T. ALARCÓN, M. LÓPEZ-BREA    

 

Introduction. The aim of this study was to characterize the mutations types present in the 23S rRNA gene related to H. pylori clarithromycin-resistance strains in Spain and evaluate a novel PCR-RFLP method for detection of the most frequent point mutation in our population.
Methods. Gastric biopsies were obtained by endoscopy from patients with gastric symptoms. H. pylori was cultured according to standard microbiological procedures and clarithromycin resistance was determined by E-test. DNA extraction was performed by NucliSens platform with the NucliSens magnetic extraction reagents (bioMérieux) according to the manufacturer instructions. Analyses for point mutations in 23S rRNA gene strains were performed by sequence analysis of amplified polymerase chain reaction products. Restriction fragment length polymorphism was performed using BsaI enzyme to detect restriction sites that correspond to the mutation (A2143G).
Results. We found 42 out of 118 (35.6%) strains resistant to clarithromycin by E-test. E-test results were confirmed for the presence of point mutation in 34 (88.1%) of these strains. Mutation A2143G was found in 85.3% of the strains. Analyses with the restriction enzyme BsaI was able to confirm the presence of A2143G mutation. There were 8 H. pylori strains resistant to clarithromycin by E-test but without any point mutationin the 23 rRNA gene.
Conclusions. We conclude that PCR-RFLP is a reliable method to detect clarithromycin-resistance H. pylori strains in countries with a high prevalence of clarithromycin-resistance as Spain. It may be useful before choosing regimens of H. pylori eradication.    

 
Rev Esp Quimioter 2011:24(1):32-36 [pdf]

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Rev Esp Quimioter 2011:24(3):136-142

Which is the best empirical treatment in patients with urethritis?      

M. A. ORELLANA, M. L. GÓMEZ–LUS            

 

Objective. To know the best empirical treatment of urethritis in patients at the City Center of Madrid.
Methods. 2.021 urethral exudates were analyzed in men between January 2003-December 2007. In addition to the traditional cultures, it was determined the presence of Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, Trichomonas vaginalis and Herpes simplex. The susceptibility of N.gonorrhoeae and Haemophilus spp was performed by disk diffusion method and U. urealyticum by Mycoplasma IST.
Results. The percentage of positive samples was: 30.6%. The most frequently isolated microorganisms were: U. urealyticum 9.9%, N. gonorrhoeae 7.4%, C. trachomatis 5.1% and Haemophilus spp 3.8%. The resistance of N. gonorrhoeae in the first period was: penicillin 11.8%, tetracycline 5.9%, ciprofloxacin 8.8% and presence of betalactamase 11.8%. In the second period: penicillin 9.7%, amoxicillin/clavulanic acid 1.4%, tetracycline 8.3%, ciprofloxacin 23.6% and presence of betalactamase 10.5%. Resistance to ciprofloxacin in non-MSM (men having sex with men) was 20% and in MSM 56.2% (p <0.05). Resistance of Haemophilus spp in the first period was: 38.2% ampicillin, amoxicillin/clavulanic acid 8.8%, clarithromycin 35.3%, cotrimoxazole 64.7%, cefuroxime 5.9%, ciprofloxacin 8.8%, tetracycline 12.1% and presence of betalactamase 26.5%. In the second period: presence of betalactamase 41.9%, ampicillin 53.1%, amoxicillin/clavulanic acid 9.4%, cefuroxime 9.4%, clarithromycin 18.7%, tetracycline 34.4%, ciprofloxacin 15.6%, and cotrimoxazole 68.7%. Resistance of U. urealyticum was: ciprofloxacin 80.7%, ofloxacin 32.4%, erythromycin 17.5%, azithromycin 9.6%, tetracycline 3.5% and doxycycline 0.8%.
Conclusions. N. gonorrhoeae showed a level of resistance to tetracycline and ciprofloxacin higher in the second period, being significant for ciprofloxacin (p<0.05). Quinolone resistance was higher in MSM. Haemophilus spp showed a level of resistance to ampicillin, ciprofloxacin and tetracycline higher in the second period, being significant for tetracycline (p <0.05). U.urealyticum showed high level of resistance to ciprofloxacin (80.7%) and ofloxacin (32.4%) and low level of resistance to doxycycline (0.8%) and tetracycline (3.5%).

 

 
Rev Esp Quimioter 2011:24(3):136-142 [pdf]

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