Evaluation of different phenotypic methods to detect methicillin resistance in Staphylococcus aureus isolates recovered from cystic fibrosis patients.

Methicillin-resistant Staphylococcus aureus (MRSA) detection in cystic fibrosis (CF) is challenging. We compared different phenotypic methods among 157 S. aureus from 136 CF-patients: cefoxitin (FOX) and oxacillin (OXA) broth-microdilution; MicroScan-WalkAway®; FOX and OXA disk-diffusion (DD), and PBP2a-latex agglutination. PCR detection of mecA/mecC was the gold standard. Growth on ChromIDTM-MRSA agar was evaluated and compared with that of 157 blood culture (BC) isolates. ChromIDTM-MRSA was also tested on sputa from 111 CF-patients. 32 isolates (20%) were mecA-positive. Both FOX DD and MicroScan-WalkAway® (FOX/OXA) showed the highest sensitivity and specificity (100% and 100%, 96.9% and 99.2%, 96.9% and 100%). ChromIDTM-MRSA showed an excellent sensitivity for BC and CF-isolates (100% and 96.9%) but a poorer specificity for CF ones (95.5% vs. 73.7%), which was also observed when samples were seeded on this medium. FOX DD and MicroScan-WalkAway® are suitable for MRSA detection among CF-isolates and should be used to confirm ChromIDTM-MRSA positive CF-cultures.

Tres claves para seleccionar el antibiótico oral adecuado en las infecciones respiratorias / Three keys to the appropriate choice of oral antibiotic treatment in the respiratory tract infections

La exacerbación de la enfermedad pulmonar obstructiva crónica y la neumonía adquirida en la comunidad son las infecciones del tracto respiratorio inferior más frecuentes en la práctica clínica diaria. La selección del antibiótico es un componente crucial en su tratamiento y, en la mayoría de las ocasiones, se realiza de forma empírica. Las sociedades científicas elaboran recomendaciones terapéuticas basadas en la evidencia científica y/o recomendaciones de expertos que son de gran ayuda para los clínicos. Los betalactámicos, las fluoroquinolonas y los macrólidos son los fármacos más utilizados por vía oral. Desde un punto de vista práctico, existen tres claves para la adecuada elección del tratamiento antibiótico oral, que son la efectividad, la seguridad y el impacto ecológico en la microbiota del paciente, incluyendo el desarrollo de resistencias, que van a ser valoradas en profundidad en esta revisión

Exacerbation of chronic obstructive pulmonary disease and community-acquired pneumonia are the most frequent infections of the lower respiratory tract in daily clinical practice. Antibiotic selection is a crucial component in its treatment and, in most cases, it is performed empirically. Scientific societies make therapeutic recommendations based on scientific evidence and / or expert recommendations that are of great help to clinicians. Beta-lactams, fluoroquinolones and macrolides are the most commonly used drugs for oral administration. From a practical point of view, there are three keys to the appropriate choice of oral antibiotic treatment, which are the effectiveness, safety and the ecological impact on the patient's microbiota, including the development of resistance, which will be assessed in depth in this review

Hypermucoviscous Klebsiella pneumoniae: A challenge in community acquired infection.

In 1986, a new syndrome was described in Taiwan secondary to hypervirulent K. pneumoniae (hvKP), and its main feature was the ability to cause severe infection in young and immunocompetent hosts. Their virulence is explained by the efficient acquisition of iron and an increase in capsule production, which confer the characteristic hypermucoviscous phenotype. Most of these cases have been described in Asia and subsequently spread to America and Europe, where their prevalence is much lower. We present four cases of bacteremia and liver abscesses secondary to hypervirulent K. pneumoniae, two of them associated with endophthalmitis. K. pneumoniae isolates recovered from two of the patients belonged to capsular serotype K1 (genes wzx_K1 and magA), while the other two were K2 (gene wzy_K2). Both of the K1 isolates were classified into a ST23, and isolates of serotype K2 belonged to the ST375 and ST881 clones. In Europe, hvKP isolates are less frequently recovered, mostly associated with Asian citizens or travelers, which was not the case in our patients. K1 capsular serotype is a major cause of primary liver abscess and secondary septic embolus, and K2 is associated with secondary liver abscess. Although these hypervirulent variants usually affect immunocompetent patients as in our cases, diabetes mellitus is a major risk factor for the most invasive cases, with concomitant poor prognosis. Identification of hypervirulent K. pneumoniae serotypes K1 and K2 should be considered as part of the microbiological diagnosis of community-acquired liver abscess due to their clinical implications.