José Antonio Lepe

Emergence of resistance to daptomycin in a cohort of patients with methicillin-resistant Staphylococcus aureus persistent bacteraemia treated with daptomycin

4 Theoretically estimated AUC 24 /MIC ratios against VRE susceptible to linezolid, according to the EUCAST clinical breakpoint (MIC¼ 4 mg/L), 1 were in the recommended range for the effective treatment of severe infections with linezolid (AUC 24 /MIC ratio of 80 –120) 6 in both cases (.93.76 and .250.96, respectively). In addition , biliary trough levels (C min) of linezolid were above the EUCAST clinical breakpoint against VRE in both cases (7.42 and 37.53 mg/L, respectively), this ensuring a theoretical T .MIC of .100%. The wide interindividual pharmacokinetic variability of linezolid observed between the two patients (patient 1: V ss 31. 5 L, CL 4.2 L/h and t 1/2 5.2 h; patient 2: V ss 67.1 L, CL 1.6 L/h and t 1/2 29.1 h) confirmed previous observations in critically ill patients during treatment with linezolid. 8 This variability is expected to potentially impact more on tolerability than on efficacy. Notably, patient 2 experienced hyperlactacidaemia (an increase in lactate level of 6.2 mmol/L during linezolid treatment), which could have been related to drug overexposure potentially favoured by drug –drug interactions and renal impairment. 8 However, it should not be overlooked that linezolid has generally been shown to be safe and effective in LTx patients. 9 The therapeutic drug monitoring of plasma C min may represent a valuable tool for the optimal management of linezolid in these cases, 8 and has recently been shown to improve safety outcomes in long-term treatment. 10 We recognize that the absence of real biliary pharmacokinetic/ pharmacodynamic data may be a limitation. However, these data confirm the potentially valuable role of linezolid in the treatment of cholangitis due to multidrug-resistant Enterococcus in LTx patients, since they meet the recommendations of good biliary penetration that are given in the Tokyo guidelines. References 1 Asín E, Isla A, Canut A et al. Comparison of antimicrobial pharmacokinetic/pharmacodynamic breakpoints with EUCAST and CLSI clinical breakpoints for Gram-positive bacteria. 4 Cremaschi E, Maggiore U, Maccari C et al. Linezolid levels in a patient with biliary tract sepsis, severe hepatic failure and acute kidney injury on sustained low-efficiency dialysis (SLED). 5 Pea F, Viale P, Lugano M et al. Biliary penetration and pharmacodynamic exposure of linezolid in liver transplant patients. 6 Rayner CR, Forrest A, Meagher AK et al. Clinical pharmacodynamics of linezolid in seriously ill patients treated in a compassionate use programme. 7 Pea F, Viale P, Lugano M et …

Global impact of an educational antimicrobial stewardship programme on prescribing practice in a tertiary hospital centre

The misuse of antibiotics has been related to increased morbidity, mortality and bacterial resistance. The development of antimicrobial stewardship programmes (ASPs) has been encouraged by scientific societies as an essential measure. An educational, institutionally supported ASP was developed in our tertiary-care centre. Local guidelines on the management of infectious syndromes were created. Antimicrobial prescriptions were chosen arbitrarily weekly and counselling interviews by expert clinicians were carried out, using a paedagogic, non-restrictive methodology. Satisfaction with the interview was assessed using anonymous questionnaires. The appropriateness of antimicrobial prescriptions as well as consumption was assessed prospectively throughout the year. Feedback regarding the correct use of treatments was communicated to each participating department periodically. The improvement in antimicrobial prescription was included among the annual objectives linked to economic incentives in every department. A total of 1206 counselling interviews were carried out during the first year. Fifty-three per cent of antimicrobial prescriptions (176/332) were inappropriate when the programme started. The rate of inappropriate prescriptions continuously declined to 26.4% (107/405) in the fourth trimester (p <0.001; RR = 0.38; 95% CI, 0.23-0.43). Antimicrobial consumption decreased from 1150 defined daily doses (DDDs) per 1000 occupied bed-days in the first trimester to 852 DDDs in the fourth, reflecting a reduction in antimicrobial expenditures of 42%. A total of 352 satisfaction questionnaires were received and 98% described the advice as positive. In conclusion, the implementation of an education-based ASP achieved a significant improvement in all antimicrobial prescriptions in the centre and a reduction in antimicrobial consumption, even when no restrictive measures were implemented. The programme was highly accepted by all prescribers.

Efficacy of Daptomycin versus Vancomycin in an Experimental Model of Foreign-Body and Systemic Infection Caused by Biofilm Producers and Methicillin-Resistant Staphylococcus epidermidis

ABSTRACT Staphylococcus epidermidis is a frequent cause of device-associated infections. In this study, we compared the efficacy of daptomycin versus vancomycin against biofilm-producing methicillin-resistant S. epidermidis (MRSE) strains in a murine model of foreign-body and systemic infection. Two bacteremic biofilm-producing MRSE strains were used (SE284 and SE385). The MIC of daptomycin was 1 mg/liter for both strains, and the MICs of vancomycin were 4 and 2 mg/liter for SE284 and for SE385, respectively. The in vitro bactericidal activities of daptomycin and vancomycin were evaluated by using time-kill curves. The model of foreign-body and systemic infection of neutropenic female C57BL/6 mice was used to ascertain in vivo efficacy. Animals were randomly allocated into three groups (n = 15): without treatment (controls) or treated with daptomycin at 50 mg/kg/day or vancomycin at 440 mg/kg/day. In vitro, daptomycin showed concentration-dependent bactericidal activity, while vancomycin presented time-dependent activity. In the experimental in vivo model, daptomycin and vancomycin decreased liver and catheter bacterial concentrations (P < 0.05) and increased the survival and the number of sterile blood cultures (P < 0.05) using both strains. Daptomycin produced a reduction in the bacterial liver concentration higher than 2.5 log10 CFU/g compared to vancomycin using both strains, with this difference being significant (P < 0.05) for infection with SE385. For the catheter bacterial concentrations, daptomycin reduced the concentration of SE284 3.0 log10 CFU/ml more than did vancomycin (P < 0.05). Daptomycin is more effective than vancomycin for the treatment of experimental foreign-body and systemic infections by biofilm-producing methicillin-resistant S. epidermidis.

Diagnóstico microbiológico de las infecciones de transmisión sexual (2007)

Las infecciones de transmision sexual (ITS) constituyen un importante problema de salud publica a nivel mundial. El diagnostico microbiologico precoz mediante tecnicas sensibles y especificas es crucial para una reduccion exitosa de la transmision y de las secuelas de las ITS. La presente revision realiza una descripcion de los metodos actuales empleados en el diagnostico. Neisseria gonorrhoeae y Chlamydia trachomatis son los patogenos mas frecuentes en la uretritis y la cervicitis. El cultivo sigue siendo la tecnica de referencia para el diagnostico de la gonococia; en el caso de C. trachomatis, las tecnicas de amplificacion de acidos nucleicos se consideran el nuevo patron de referencia, aunque el cultivo sigue siendo la tecnica mas especifica. Las ulceras genitales debidas a Treponema pallidum, Haemophilus ducreyi o virus del herpes simple tienen una pequena correlacion clinicobacteriologica y, por tanto, es esencial llevar a cabo estudios microbiologicos para establecer el diagnostico. Las lesiones presentes en el periodo primario o secundario de la sifilis se pueden diagnosticar por microscopia de campo oscuro; el diagnostico serologico en el resto de periodos implica la realizacion de pruebas no treponemicas junto con pruebas treponemicas confirmatorias. Para el virus del herpes simple, el cultivo celular se considera el metodo de referencia; los metodos moleculares tambien tienen una sensibilidad y especificidad cercanas al 100%. Actualmente, el diagnostico microbiologico de H. ducreyi y del linfogranuloma venereo se basa en el empleo de tecnicas moleculares sobre muestras obtenidas de la ulceracion o adenopatia. El diagnostico de las verrugas genitales en el paciente inmunocompetente en la mayoria de los casos es solo clinico al ser las lesiones suficientemente caracteristicas. Respecto a las infecciones por Trichomonas vaginalis, el cultivo se considera el metodo de referencia.

Mortality and hospital stay related to coagulase-negative Staphylococci bacteremia in non-critical patients

OBJECTIVES To describe the morbidity and mortality related to coagulase-negative Staphylococci (CNS) bacteremia in non-critical patients. METHODS Prospective, matched case-control study nested in a cohort. Patients with CNS bacteremia and no other isolate in blood cultures during their admission were defined as cases. Each case was matched by age, sex and area of hospitalization to one control. A 30-day follow-up was performed. Mortality and hospital stay were defined as endpoints. RESULTS 105 cases and 105 controls were included. All cases carried intravascular catheters at the time of inclusion. Cases presented higher mortality compared to controls (14.3% vs. 4.8%), although this association was not independent in a multivariate analysis (p = 0.11). CNS bacteremia was independently associated with longer hospital stay (mean 12 vs. 8.5 days, p = 0.008). Moreover, when patients with CNS bacteremia were specifically analyzed, the persistence of fever (p = 0.005) and inappropriate empirical treatment (p = 0.04) were independently related to mortality. CONCLUSION We did not observe increased mortality attributable to CNS bacteremia, although it was associated with longer hospitalizations. Early appropriate empirical antibiotic therapy pending blood culture results might improve the outcome of patients with CNS bacteremia. Close follow-up is recommended if fever persists beyond 72 h.

Quantitative Real-Time PCR for Detection of Acinetobacter baumannii Colonization in the Hospital Environment

ABSTRACT A real-time PCR assay was developed for detecting the presence of Acinetobacter baumannii on hospital equipment and compared to conventional bacterial culture using 100 hospital environmental samples. The real-time PCR detected contaminated surfaces in 4 h with high sensitivity (100%) compared to conventional culture. Thirty-eight percent of samples were positive by real-time PCR and negative by bacterial culture (false positives), possibly indicating the widespread presence of bacterial DNA that is not associated with viable bacteria.

Uso prudente de antibióticos y propuestas de mejora desde la medicina hospitalaria

The largest consumption of antimicrobials is concentrated in hospitals and within them, the intensive care units. The quality of antimicrobial use is not optimal, with up to 50% of prescriptions being unnecessary or inappropriate. Inappropriate antibiotic use leads to severe consequences, such as increased patient mortality and morbidity and bacterial resistance. The primary reason for inappropriate use is the insufficient knowledge of the increasingly vast and complex information about the diagnosis and treatment of infectious diseases. There is general agreement on the need to improve the use of antimicrobials in hospitals but not on how to improve it. University Hospital Virgen del Rocío (Seville) has launched the Institutional Programme for the Optimisation of Antimicrobial Treatment (PRIOAM), inspired by the recommendations of the Infectious Diseases Society of America and adapted to the structural, functional and cultural characteristics of the hospital. PRIOAM is coordinated by a multidisciplinary team chosen by the Committee on Infections and Antimicrobials and has three basic characteristics: it is an institutional programme that has incentives linked to achieving goals; it is an educational programme in which training and knowledge are the basis for the proper use of antimicrobials; and it is a programme subject to results, in which the main objectives are clinical, not economic, to reduce mortality and morbidity in patients with infections and to delay the development of resistance.The largest consumption of antimicrobials is concentrated in hospitals and within them, the intensive care units. The quality of antimicrobial use is not optimal, with up to 50% of prescriptions being unnecessary or inappropriate. Inappropiate antibiotic use leads to severe consequences, such as increased patient mortality and morbidity and bacterial resistance. The primary reason for inappropriate use is the insufficient knowledge of the increasingly vast and complex information about the diagnosis and treatment of infectious diseases. There is general agreement on the need to improve the use of antimicrobials in hospitals but not on how to improve it. University Hospital Virgen del Rocio (Seville) has launched the Institutional Programme for the Optimisation of Antimicrobial Treatment (PRIOAM), inspired by the recommendations of the Infectious Diseases Society of America and adapted to the structural, functional and cultural characteristics of the hospital. PRIOAM is coordinated by a multidisciplinary team chosen by the Committee on Infections and Antimicrobials and has three basic characteristics: it is an institutional programme that has incentives linked to achieving goals; it is an educational programme in which training and knowledge are the basis for the proper use of antimicrobials; and it is a programme subject to results, in which the main objectives are clinical, not economic, to reduce mortality and morbidity in patients with infections and to delay the development of resistance.

Development and validation of the INCREMENT-ESBL predictive score for mortality in patients with bloodstream infections due to extended-spectrum-β-lactamase-producing Enterobacteriaceae

Background. Bloodstream infections (BSIs) due to ESBL-producing Enterobacteriaceae (ESBL-E) are frequent yet outcome prediction rules for clinical use have not been developed. The objective was to define and validate a predictive risk score for 30 day mortality. Methods. A multinational retrospective cohort study including consecutive episodes of BSI due to ESBL-E was performed; cases were randomly assigned to a derivation cohort (DC) or a validation cohort (VC). The main outcome variable was all-cause 30 day mortality. A predictive score was developed using logistic regression coefficients for the DC, then tested in the VC. Results. The DC and VC included 622 and 328 episodes, respectively. The final multivariate logistic regression model for mortality in the DC included age >50 years (OR = 2.63; 95% CI: 1.18–5.85; 3 points), infection due to Klebsiella spp. (OR = 2.08; 95% CI: 1.21–3.58; 2 points), source other than urinary tract (OR = 3.6; 95% CI: 2.02–6.44; 3 points), fatal underlying disease (OR = 3.91; 95% CI: 2.24–6.80; 4 points), Pitt score >3 (OR = 3.04; 95 CI: 1.69–5.47; 3 points), severe sepsis or septic shock at presentation (OR = 4.8; 95% CI: 2.72–8.46; 4 points) and inappropriate early targeted therapy (OR = 2.47; 95% CI: 1.58–4.63; 2 points). The score showed an area under the receiver operating curve (AUROC) of 0.85 in the DC and 0.82 in the VC. Mortality rates for patients with scores of < 11 and ≥11 were 5.6% and 45.9%, respectively, in the DC, and 5.4% and 34.8% in the VC. Conclusions. We developed and validated an easy-to-collect predictive scoring model for all-cause 30 day mortality useful for identifying patients at high and low risk of mortality.

Characteristics and Outcome of Streptococcus pneumoniae Endocarditis in the XXI Century: A Systematic Review of 111 Cases (2000–2013)

AbstractStreptococcus pneumoniae is an infrequent cause of severe infectious endocarditis (IE). The aim of our study was to describe the epidemiology, clinical and microbiological characteristics, and outcome of a series of cases of S. pneumoniae IE diagnosed in Spain and in a series of cases published since 2000 in the medical literature.We prospectively collected all cases of IE diagnosed in a multicenter cohort of patients from 27 Spanish hospitals (n = 2539). We also performed a systematic review of the literature since 2000 and retrieved all cases with complete clinical data using a pre-established protocol. Predictors of mortality were identified using a logistic regression model.We collected 111 cases of pneumococcal IE: 24 patients from the Spanish cohort and 87 cases from the literature review. Median age was 51 years, and 23 patients (20.7%) were under 15 years. Men accounted for 64% of patients, and infection was community-acquired in 96.4% of cases. The most important underlying conditions were liver disease (27.9%) and immunosuppression (10.8%). A predisposing heart condition was present in only 18 patients (16.2%). Pneumococcal IE affected a native valve in 93.7% of patients. Left-sided endocarditis predominated (aortic valve 53.2% and mitral valve 40.5%). The microbiological diagnosis was obtained from blood cultures in 84.7% of cases. In the Spanish cohort, nonsusceptibility to penicillin was detected in 4.2%. The most common clinical manifestations included fever (71.2%), a new heart murmur (55%), pneumonia (45.9%), meningitis (40.5%), and Austrian syndrome (26.1%). Cardiac surgery was performed in 47.7% of patients. The in-hospital mortality rate was 20.7%. The multivariate analysis revealed the independent risk factors for mortality to be meningitis (OR, 4.3; 95% CI, 1.4–12.9; P < 0.01). Valve surgery was protective (OR, 0.1; 95% CI, 0.04–0.4; P < 0.01).Streptococcus pneumoniae IE is a community-acquired disease that mainly affects native aortic valves. Half of the cases in the present study had concomitant pneumonia, and a considerable number developed meningitis. Mortality was high, mainly in patients with central nervous system (CNS) involvement. Surgery was protective.

Determining accurate vancomycin MIC values for methicillin-resistant Staphylococcus aureus by the microdilution method

OBJECTIVES To model the standard broth microdilution method, based on a modified Gompertz function, to obtain accurate vancomycin MIC values for methicillin-resistant Staphylococcus aureus (MRSA). The effect of these MIC values on the vancomycin therapeutic target of AUC(0-24)/MIC ≥ 400 was evaluated. METHODS Three clinical isolates of MRSA with different vancomycin MIC values were used in this model. The optical densities (OD) of each MIC determination were modelled by a non-linear regression method using an F-test. The OD data were adjusted to the Gompertz equation to obtain the MIC values. The mean vancomycin AUC(0-24) obtained with a 30 mg/kg/day dosing schedule was calculated using a Monte Carlo simulation over 5000 subjects, using the pharmacokinetic data obtained in vancomycin-treated patients in our hospital. RESULTS Although the MIC values obtained with this model were lower than those of the diffusion method (Etest) in all three cases, this did not affect the AUC(0-24)/MIC ratio for the strains with MICs of 1 mg/L by Etest. However, in those strains with MIC values >1 mg/L, the confidence intervals obtained for this ratio included values <400. CONCLUSIONS The inherent variability of the broth microdilution method could explain the differences in the clinical outcome in MRSA-infected patients treated with vancomycin, mainly in those due to strains with MIC values of 1.5-2 mg/L by Etest, because the corresponding MIC values would range from 0.84 to 1.52 mg/L by the microdilution method, which could affect the therapeutic target.