Antimicrobial activity of ceftolozane-tazobactam against multidrug-resistant and extensively drug-resistant Pseudomonas aeruginosa clinical isolates from a Spanish hospital.

OBJECTIVE: Our objective was to evaluate the in vitro activity of ceftolozane-tazobactam against multidrug resistant (MDR) and extensively drug-resistant (XDR) non metallo-ß-lactamase producing Pseudomonas aeruginosa clinical isolates at Hospital Universitario Miguel Servet (Zaragoza, Spain) from February 2016 to October 2017. METHODS: We evaluated the in vitro activity of ceftolozane-tazobactam and other antipseudomonal antibiotics against 12 MDR and 117 XDR non metallo-ß-lactamase producing P. aeruginosa isolates. Ceftolozane-tazobactam minimal inhibitory concentrations (MICs) were determined by MIC gradient diffusion test strip. RESULTS: Among the 129 MDR/XDR isolates included, 119 (92.2%) were susceptible to ceftolozane-tazobactam, and ten (7.8%) were resistant. MIC50 was 2 mg/L, and MIC90 4 mg/L. Ceftolozane-tazobactam was the second most active antibiotic after colistin, overtaking amikacin. CONCLUSIONS: Ceftolozane-tazobactam is a valuable treatment option for MDR and XDR P. aeruginosa infections in our setting.

[Surveillance of commensal flora evolution and infections in neutropenic cancer patients submitted to chemoprophylaxis]. / Vigilancia de la evolución de la flora comensal y de las infecciones en pacientes oncológicos con neutropenia sometidos a quimioprofilaxis.

The evolution of the flora and its resistance to different antimicrobials in neutropenic patients submitted to high-dose chemotherapy with autologous blood stem-cell transplantation, and the relation of these findings to the etiology of the infections the patients developed was studied in order to evaluate the suitability of the chemoprophylaxis and the empirical antibiotic therapy used. Forty-one patients were analyzed in a period of 28 months. The chemoprophylaxis used was levofloxacin, fluconazole and acyclovir. The empirical sequential treatment was an initial administration of cefepime, followed by teicoplanin and amikacin. Cultures were done of nasal and pharyngeal smears, Hickman catheter and stools, 1 day before chemoprophylaxis started and then on days 5 and 9. In the case of fever, three sets of blood cultures and urine cultures were done and samples from areas related to the clinical condition were analyzed. Levofloxacin induced the selection of resistant strains or species in the flora and in the infectious agents. Fluconazole also selected resistant species in the flora. Seventeen infections were documented in eleven patients, produced by Gram-positive bacteria in thirteen cases (81.25%) and by Gram-negative bacteria in three (18.75%). The coagulase negative staphylococci and Enterococcus faecalis were the most frequent agents of infection. We identified on nine occasions the same microorganism in the flora and in the pathological product; this suggests its endogenous origin and supports the use of prospective cultures of the flora, monitoring the sensibility of the microorganisms isolated to the antimicrobials used in chemoprophylaxis and empirical treatment.

Vigilancia de la evolución de la flora comensal y de las infecciones en pacientes oncológicos con neutropenia sometidos a quimioprofilaxis / Surveillance of comensal flora evolution and infections in neutropenic cancer patients submitted to chemoprophylaxis

Estudiamos cómo evoluciona el tipo de flora comensal y su resistencia a distintos antimicrobianos en pacientes neurotropénicos sometidos a quimioterapia de altas dosis con autotrasplante de células madre autólogas hematopoyéticas periféricas, relacionando los hallazgos con la etiología de las infecciones que desarrollaron los pacientes, a fin de evaluar la idoneidad de la quimioprofilaxis y del tratamiento empírico utilizados. Se analizaron 41 pacientes en un periodo de 28 meses. La quimioprofilaxis se realizó con levofloxacino, fluconazol y aciclovir. El tratamiento empírico secuencial preveía la administación inicial de cefepima, seguida de teicoplanina y amikacina. Se realizaron cultivos de frotis nasales y faríngeo, catéter de Hickman y heces, un día antes de comenzar la quimioprofilaxis, a los cinco y nueve días. En caso de fiebre se realizaron tres hemocultivos y cultivo de orina y de muestras procedentes de focos relacionados con la clínica. El levofloxacino indujo la selección de cepas o especies resistentes, tanto en la flora comensal como en los agentes patógenos. El fluconazol seleccionó especies resistentes en la flora comensal. Se documentaron microbiológicamente 17 infecciones en 11 pacientes, producidas por gram positivos en 13 casos (81.25%) y por gramnegativos en 3 (18,75%). Los estafilococos coagulasa negativos y Enterococcus faecalis fueron los microorganismos más frecuentes. En nueve ocasiones recuperamos el mismo microorganismo en flora comensal y producto patológico, lo que sugiere su origen endógeno y apoya la realización prospectiva de cultivos de flora comensal, vigilando la sensibilidad de los microorganismos aislados a los antimicrobianos usados en quimioprofilaxis y tratamiento empírico

The evolution of the flora and its resistance to different antimicrobials in neutropenic patients submitted to high-dose chemotherapy with autologous blood stem-cell transplantation, and the relation of these findings to the etiology of the infections the patients developed was studied in order to evaluate the suitability of the chemoprophylaxis and the empirical antibiotic therapy used. Forty-one patients were analysed in a period of 28 months. The chemoprophylaxis used was levofloxacin, fluconazole and acyclovir. The empirical sequential treatment was an initial administration of cefepime, followed by teicoplanin and amikacin. Cultures were done of nasal and pharyngeal smears, Hickman catheter and stools, 1 day before chemoprophylaxis started and then on days 5 and 9. In the case of fever, three sets of blood cultures and urine cultures were done and samples from areas related to the clinical condition were analysed. Levoflaxacin induced the selection of resistant strains or species in the flora and in the infectious agents. Fluconazole also selected resistant species in the flora. Seventeen infections were documented in eleven patients, produced by Gram-positive bacteria in thirteen cases (81.25%) and by Gram-negative bacteria in three (18.75%). The coagulase negative staphylococci and Enterococcus faecalis were the most frequent agents of infection. We identified on nine occasions the same microorganism in the flora and in the pathological product; this suggest its endogenous origin and supports the use of prospective cultures of the flora, monitoring the sensibility of the microorganisms isolated to the antimicrobials used in chemoprophylasis and empirical treatment