Evaluation of three Immunochromatographic Assays for Detection of Legionella pneumophila serogroup 1 Antigen in Urine Samples

Los métodos inmunocromatográficos Uni-Gold, SAS y BinaxNOW para la detección cualitativa del antígeno de Legionellapneumophila serogrupo 1 en orina fueron comparadosempleando 39 muestras de orina, sin congelar y sin concentrar,de pacientes con Enfermedad del Legionario. La prueba Uni-Gold detectó el antigen en el 41% de los casos (16/39), SAS enel 61,5% (24/39) y Binax NOW en el 74,3% (29/39). La pruebaBinax NOW mostró los mejores resultados en la detección delantígeno de L. pneumophila serogrupo 1 en muestras de orina(AU)

The Uni-Gold, the SAS and the Binax NOW immunochromatographictest (ICT) urinary antigen assays for the qualitativedetection of Legionella pneumophila serogroup 1 were comparedusing 39 unfrozen and nonconcentrated urine samplesfrom patients with Legionnaires´ disease (LD). The Uni-Gold antigentest detected the urinary antigen in 41% (16/39), the SASantigen test in 61.5% (24/39), and the Binax NOW antigen test in74.3% (29/39). The Binax NOW ICT assay showed the best resultswhen detecting L. pneumophila urinary antigen(AU)

Evaluation of three immunochromatographic assays for detection of Legionella pneumophila serogroup 1 antigen in urine samples.

The Uni-Gold, the SAS and the Binax NOW immunochromatographic test (ICT) urinary antigen assays for the qualitative detection of Legionella pneumophila serogroup 1 were compared using 39 unfrozen and nonconcentrated urine samples from patients with Legionnaires disease (LD). The Uni-Gold antigen test detected the urinary antigen in 41% (16/39), the SAS antigen test in 61.5% (24/39), and the Binax NOW antigen test in 74.3% (29/39). The Binax NOW ICT assay showed the best results when detecting L. pneumophila urinary antigen.

[Implication of ermX genes in macrolide- and telithromycin-resistance in Corynebacterium jeikeium and Corynebacterium amycolatum]. / Implicacion de los genes ermX en la resistencia a los macrolidos y la telitromicina de Corynebacterium jeikeium y Corynebacterium amycolatum.

The activity of seven macrolides, clindamycin and telithromycin against clinical isolates of Corynebacterium spp. was studied. Of these, 36 isolates were identified as C. jeikeium and 57 as C. amycolatum. The frequency of resistance to erythromycin and other macrolides as well as clindamycin was high, with CMI(90) >256 microg/ml. Telithromycin showed the best activity, with 52.3% of C. amycolatum and 70% of C. jeikeium erythromycin-resistant strains susceptible to this ketolide. All strains had the MLSb constitutive phenotype. The ermX gene was present in all erythromycin-resistant strains, and in C. amycolatum was 100% homologous with that of C. striatum and C. diphtheriae.

Molecular diversity of quinolone resistance in genetically related clinical isolates of Staphylococcus aureus and susceptibility to newer quinolones.

The genes encoding topoisomerases (gyrA and grlA) and the norA promoter of 100 fluoroquinolone-susceptible and -resistant Staphylococcus aureus clinical isolates obtained in two geographically distant hospitals were analysed. The relationship between mutations found and the susceptibility to newer quinolones was determined. Thirty-nine strains were grouped in seven clones by pulsed-field gel electrophoresis (PFGE). The remaining 61 strains were classified as unrelated strains. In three clones, all strains showed the same grlA-gyrA-norA mutation profiles. Strains in the rest of the groups showed different mutation profiles, even though PFGE indicated that they possessed genetically similar populations. One cluster showed a high level of diversity; five different mutation profiles were detected in the six isolates belonging to this pattern. Two isolates had a Glu84 to Lys mutation in grlA and another isolate had this mutation combined with a Ser84 to Leu mutation in gyrA. Combination of a Ser80 to Phe mutation in grlA and a Ser84 to Leu in gyrA was found in the two other isolates. One of these also had a thymine to a guanine transversion at a position 89 nucleotides upstream of the norA start codon in the norA promoter. These results show that fluoroquinolone resistance in clinical S. aureus strains does not necessarily result from the spread of resistant clones. Fluoroquinolone resistance may develop independently in strains belonging to the same PFGE pattern by accumulation of different mutations over a quinolone-susceptible ancestor wild type or single grlA mutant.

[Activity of new quinolones against clinical isolates of Corynebacterium species]. / Actividad de nuevas quinolonasfrente a aislamientos clínicosde Corynebacterium spp.

The activity of six quinolones (ciprofloxacin, levofloxacin, trovafloxacin, moxifloxacin, clinafloxacin and grepafloxacin) against 86 clinical isolates of Corynebacterium spp. obtained from different clinical sources was studied. Of these, 30 isolates were identified as C. jeikeium, 30 as C. urealyticum and 26 as C. amycolatum. C. amycolatum was the most resistant species, with 85.5% of the strains analyzed resistant to all the quinolones studied. Clinafloxacin showed the best activity against these species with a concentration range between <0.01 and 8 mg/l, and MIC50 and MIC90 64 and 32 times lower, respectively, than the MICs of ciprofloxacin. The majority of the isolates (90%) of C. jeikeium and C. urealyticum were susceptible to all the quinolones studied. Only 9.9% of the C. jeikeium strains and 13.2% of the C. urealyticum strains were resistant to ciprofloxacin, which showed the lowest activity of the antimicrobial agents evaluated. Clinafloxacin, grepafloxacin and moxifloxacin were the most active quinolones against these two multiresistant species.

[In vitro activity of new quinolones against clinical strains of Staphylococcus aureus of the wild type and with mutations characterized by gyrA, gyrB and grlA]. / Actividad in vitro de nuevas quinolonasfrente a cepas clínicas de Staphylococcus aureussilvestres y con mutaciones caracterizadasen gyrA, gyrB y grlA.

The aim of this study was to determine the in vitro activity of five quinolones against clinical strains of methicillin-susceptible and -resistant Staphylococcus aureus clinical isolates characterized at the molecular level with respect to the presence of mutations in genes coding for resistance to quinolones (grlA, gyrA and gyrB). The relationship between the mutations found and the activities of these quinolones was also analyzed. Trovafloxacin was the most active against methicillin-susceptible S. aureus and showed good activity against methicillin-resistant S. aureus, with a MIC90 of 2 mg/l. The grlA-gyrA double mutation was the most frequent (55% of the strains). Single mutation in grlA was detected only in 5% of strains; 39% of strains showed a wild-type genotype. The grlA-gyrA double mutants presented a high level of resistance against the fluoroquinolones tested except for trovafloxacin, with the MIC ranging between 0.5 and 4 mg/l. Wild-type strains were susceptible to all the fluoroquinolones tested and the single grlA mutants had a low level of quinolone resistance but were still below the breakpoint for resistance. Trovafloxacin and sparfloxacin were less affected by this mutation.

Actividad de nuevas quinolonasfrente a aislamientos clínicosde Corynebacterium spp / Activity of new quinolones against clinical isolatesof Corynebacterium species

Se ha estudiado la actividad de seis quinolonas (ciprofloxacino, levofloxacino, trovafloxacino, moxifloxacino, clinafloxacino y grepafloxacino) frente a 86 aislamientos clínicos de Corynebacterium spp. procedentes de diferentes muestras clínicas. De éstos, 30 pertenecían a la especie C. jeikeium, 30 a C. urealyticum y 26 a C. amycolatum. La especie más resistente fue C. amycolatum, de la cual el 85,5 por ciento de las cepas estudiadas fueron resistentes a todas las quinolonas probadas, siendo clinafloxacino la que presentó una mejor actividad, con un rango de concentración entre <0,01 y 8 mg/l y CMI50 y CMI90 64 y 32 veces inferiores a las de ciprofloxacino, respectivamente. Más del 90 por ciento de las cepas de C. jeikeium y C. urealyticum fueron sensibles a todas las quinolonas, siendo ciprofloxacino la de peor actividad, con un porcentaje de cepas resistentes del 9,9 por ciento en el caso de C. jeikeium y un 13,2 por ciento para C. urealyticum. Clinafloxacino, grepafloxacino y moxifloxacino fueron las nuevas quinolonas más activas frente a estas dos especies de corinebacterias multirresistentes (AU)

Actividad in vitro de nuevas quinolonasfrente a cepas clínicas de Staphylococcus aureussilvestres y con mutaciones caracterizadasen gyrA, gyrB y grlA / In vitro activity of new quinolones against clinical strainsof Staphylococcus aureus of the wild type and with mutations characterized by gyrA, gyrB and grlA

Se ha estudiado la actividad in vitro de cinco fluoroquinolonas frente a cepas clínicas de Staphylococcus aureus, sensibles y resistentes a la meticilina, caracterizadas desde el punto de vista genético respecto a la existencia de mutaciones en los genes causantes de la resistencia a las quinolonas (grlA, gyrA y gyrB). También se comprobó el efecto de estas mutaciones en la actividad de las quinolonas. El trovafloxacino apareció como el más activo de los antimicrobianos estudiados frente a S. aureus sensibles a la meticilina (SASM), presentando también una buena actividad frente a los resistentes a ésta (SARM), con una CMI90 de 2 mg/l. El patrón más frecuente fue la doble mutación gyrA y grlA (55 por ciento de las cepas), siendo mucho menos frecuente la mutación únicamente en grlA (5 por ciento). El 39 por ciento de las cepas presentaron un genotipo silvestre. Las cepas con doble mutación presentaron altos grados de resistencia a todas las fluoroquinolonas probadas excepto a trovafloxacino, con un rango de CMI de 0,5-4 mg/l. Las cepas silvestres fueron sensibles a todas las quinolonas ensayadas; en las cinco cepas con mutación en grlA se observó un ligero aumento de las CMI para todos los antimicrobianos, aunque siempre por debajo del punto de corte que determina resistencia. Las quinolonas menos afectadas por esta mutación fueron trovafloxacino y esparfloxacino (AU)

Appearance of resistance to meropenem during the treatment of a patient with meningitis by Acinetobacter.

A case is reported of a patient who developed Acinetobacter meningitis after an external ventricular drainage system had been fitted for control of intracranial pressure. During the process, nine strains of Acinetobacter isolated from her cerebrospinal fluid were indistinguishable by analysis of total genomic DNA by pulse-field gel electrophoresis. The first eight strains were sensitive to meropenem and imipenem (MICs < 1 g/l). The MIC of the last one, which had been recovered after 32 days during two courses of treatment with meropenem, increased to > 32 g/l for meropenem, while with imipenem the increase was minimal (MIC = 1.5 g/l). The microorganism persisted in the central nervous system despite the administration of different antimicrobials, including intraventricular aminoglycosides and six changes in the external ventricular system. The patient died 68 days after admission to the intensive care unit from bilateral cerebral ischemic lesions, intraventricular hemorrhage and cerebral edema with endocraneal hypertension, the Acinetobacter ventriculitis also contributing to this state.