Carlos Robledo

Similar Frequencies of Pseudomonas aeruginosa Isolates Producing KPC and VIM Carbapenemases in Diverse Genetic Clones at Tertiary-Care Hospitals in Medellín, Colombia

ABSTRACT Carbapenem-resistant Pseudomonas aeruginosa has become a serious health threat worldwide due to the limited options available for its treatment. Understanding its epidemiology contributes to the control of antibiotic resistance. The aim of this study was to describe the clinical and molecular characteristics of infections caused by carbapenem-resistant P. aeruginosa isolates in five tertiary-care hospitals in Medellín, Colombia. A cross-sectional study was conducted in five tertiary-care hospitals from June 2012 to March 2014. All hospitalized patients infected by carbapenem-resistant P. aeruginosa were included. Clinical information was obtained from medical records. Molecular analyses included PCR for detection of bla VIM, bla IMP, bla NDM, bla OXA-48, and bla KPC genes plus pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for molecular typing. A total of 235 patients were enrolled: 91.1% of them were adults (n = 214), 88.1% (n = 207) had prior antibiotic use, and 14.9% (n = 35) had urinary tract infections. The bla VIM-2 and bla KPC-2 genes were detected in 13.6% (n = 32) and 11.5% (n = 27), respectively, of all isolates. Two isolates harbored both genes simultaneously. For KPC-producing isolates, PFGE revealed closely related strains within each hospital, and sequence types (STs) ST362 and ST235 and two new STs were found by MLST. With PFGE, VIM-producing isolates appeared highly diverse, and MLST revealed ST111 in four hospitals and five new STs. These results show that KPC-producing P. aeruginosa is currently disseminating rapidly and occurring at a frequency similar to that of VIM-producing P. aeruginosa isolates (approximately 1:1 ratio) in Medellín, Colombia. Diverse genetic backgrounds among resistant strains suggest an excessive antibiotic pressure resulting in the selection of resistant strains.

Association of clinical and demographic factors in invasive candidiasis caused by fluconazole-resistant Candida species: a study in 15 hospitals, Medellín, Colombia 2010-2011.

Candida is the most important agent of fungal infections. Several risk factors have been described associated with invasive infection by fluconazole-resistant Candida spp. A prospective cross-sectional study with case-control analysis was conducted. Case group patients with fluconazole-resistant Candida isolate were included; control group were patients with fluconazole-susceptible Candida spp. A multivariate logistic regression model was performed. Three hundred isolates of Candida spp. were analyzed. Most frequent species were Candida albicans/Candida dubliniensis (48.3%) and Candida tropicalis (22.3%). Posaconazole susceptibility was 93.7%; voriconazole, 84%; and fluconazole, 78.7%. Susceptibility to anidulafungin and caspofungin was 92.7% and 92.3%, respectively. Neutropenia (adjusted odds ratio [aOR] 6.5, 95% confidence interval [CI] 1.0-43.1), antifungal exposure (aOR 5.1, 95% CI 2.3-11.2), and antituberculosis therapy (aOR 7.7, 95% CI 1.4-43.2) were associated to fluconazole resistance. Susceptibility results are useful to guide the selection of empiric antifungal treatment and the design of local therapeutic guidelines. Previous antifungal exposure suggests possible resistance to fluconazole, pointing towards the selection of a different class of antifungal agents.

Comparative study for 147 Candida spp. identification and echinocandins susceptibility in isolates obtained from blood cultures in 15 hospitals, Medellin, Colombia

OBJECTIVES Invasive candidiasis has a high impact on morbidity and mortality in hospitalised patients. Accurate and timely methods for identification of Candida spp. and determination of echinocandin susceptibility have become a priority for clinical microbiology laboratories. METHODS This study was performed to compare matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS) identification with sequencing of the D1/D2 region of the rRNA gene complex 28 subunit in 147 Candida spp. isolates obtained from patients with candidaemia. Antimicrobial susceptibility testing was performed by broth microdilution (BMD) and Etest. Sequencing of the FKS1 and FKS2 genes was performed. RESULTS The most common species isolated were Candida albicans (40.8%), followed by Candida parapsilosis (23.1%) and Candida tropicalis (17.0%). Overall agreement between the results of identification by MALDI-TOF/MS and molecular identification was 99.3%. Anidulafungin and caspofungin susceptibility by the BMD method was 98.0% and 88.4%, respectively. Susceptibility to anidulafungin and caspofungin by Etest was 93.9% and 98.6%, respectively. Categorical agreement between Etest and BMD was 91.8% for anidulafungin and 89.8% for caspofungin, with lower agreements in C. parapsilosis for anidulafungin (76.5%) and C. glabrata for caspofungin (40.0%). No mutations related to resistance were found in the FKS genes, although 54 isolates presented synonymous polymorphisms in the hotspots sequenced. CONCLUSIONS MALDI-TOF/MS is a good alternative for routine identification of Candida spp. isolates. DNA sequencing of the FKS genes suggested that the isolates analysed were susceptible to echinocandins; alternatively, unknown resistance mechanisms or limitations related to antifungal susceptibility tests may explain the resistance found in a few isolates.

Resistencia a ertapenem en 2 instituciones hospitalarias de alto nivel de complejidad: microbiología, epidemiología y factores de riesgo

INTRODUCTION Carbapenems resistance is a growing phenomenon and a threat to public health because of the reduced therapeutic options for resistant infections. METHODS A retrospective case-control study was conducted in 2 tertiary-care hospitals in Medellín, Colombia. Fifty patients infected with ertapenem-resistant enterobacteriaceae were compared with a control group consisting of 100 patients with infections caused by ertapenem susceptible enterobacteriaceae. A multivariate logistic regression model was used to identify factors that best explain ertapenem-resistant enterobacteriaceae infections. RESULTS The factors associated with ertapenem-resistant enterobacteriaceae infections were prior exposure to carbapenems (adjusted OR 3.43; 95% IC 1.08-10.87) and prior exposure to cefepime (adjusted OR 6.46; 95% IC 1.08-38.38). CONCLUSION Prior exposure to antibiotics is the factor that best explains the ertapenem-resistant enterobacteriaceae infection in this population, highlighting the importance of antimicrobial stewardship programs in hospitals.

Sensibilidad in vifro de Cepas' obtenidas ;de pacientes hospitalizados a Meropenem y otros antibióticos

Las bacterias multirresistentes producen con mayor frecuencia infecciones severas, tanto en pacientes hospitalizados, como en la comunidad. Meropenem es un carbapenem, recientemente disponible en nuestro medio. Objetivos: 1. Evaluar la sensibilidad a meropenem de cepas obtenidas de pacientes hospitalizados en distintos centros del pais; y 2. Compararla con la de otros antibioticos de uso frecuente. Metodos: 1. Se incluyeron unicamente cepas aerobias obtenidas de pacientes hospitalizados. 2. Prueba de sensibilidad in vitro por difusion de disco en agar (NCCLS). 3. Analisis comparativo de porcentajes de sensibilidad. Resultados: Participaron 8 centros de 3 ciudades. Se recolectaron 802 cepas aerobias (24.9% G+). Los principales resultados fueron (% sens)