Influencia de la correcta identificación en la interpretación de las pruebas de sensibilidad en aislados de Aeromonas spp. productoras de bacteriemia / The relevance of correct identification and interpretation of susceptibility testing of Aeromonasspp. bacteremia isolates

OBJETIVO: Estudiar la importancia de la correcta identificación a nivel de especie así como la interpretación de las pruebas de sensibilidad en aislados de Aeromonas spp. productoras de bacteriemia mediante los métodos convencionales rutinarios y los nuevos métodos moleculares. MATERIAL Y MÉTODOS: El estudio incluyó a 22 pacientes con bacteriemia por Aeromonas hydrophila grupo, identificadas mediante el sistema MicroScan. La identificación posterior a nivel de especie se realizó por espectrometría de masas y se confirmó mediante la secuenciación del gen rpoB. La actividad de imipenem, cefotaxima, piperacilina/tazobactam, ciprofloxacino y cotrimoxazol se estudió por microdilución comercial y tiras de gradiente de antibiótico con bajo y alto inóculo. La detección de carbapenemasas se realizó mediante el test de Hodge modificado y su confirmación mediante la detección por PCR del gen cphA. RESULTADOS: Se identificaron 9 (40,9%) aislamientos como Aeromonas hydrophila, 8 (36,4%) como Aeromonas veronii y los 5 (22,7%) restantes como Aeromonas caviae. La resistencia a los antibióticos betalactámicos mediante microdilución comercial y tiras de gradiente de CMI fue, respectivamente, del 36-50% para imipenem; del 4-56% para cefotaxima; y de 27-56% para piperacilina/tazobactam. La concordancia entre el sistema automatizado y el sistema de difusión con tira de gradiente antibiótico fue, globalmente para las 3 especies, del 68% para imipenem, del 50% para cefotaxima y del 46% para piperacilina/tazobactam. No se detectó resistencia a cotrimoxazol y ciprofloxacino por ambos métodos, aunque el 22,7% de las cepas fueron resistentes a ácido nalidíxico. CONCLUSIONES: Es fundamental la identificación a nivel de especie de los aislamientos de Aeromonas spp. ya que la resistencia a betalactámicos es especie y método dependiente. Los altos porcentajes de resistencia antibiótica encontrados no aconsejan el uso de antibióticos betalactámicos y quinolonas como tratamiento empírico de la infección invasiva por Aeromonas ssp

OBJECTIVE: To assess the relevance of correct identification and interpretation of susceptibility testing of Aeromonas spp. bacteremia isolates using newly developed molecular methods in comparison to previous conventional methods. MATERIAL AND METHODS: The study included 22 patients with bacteremia due to Aeromonas hydrophila group, microbiologically characterized using the MicroScan system. Further identification to species level was performed by mass spectrometry, and confirmed by sequencing the rpoB gene. The MIC of imipenem, cefotaxime, piperacillin-tazobactam, ciprofloxacin and cotrimoxazole was studied using a commercial broth microdilution and antibiotic gradient strips with low and high inocula. Detection of carbapenemase production was performed using the modified Hodge test, and was confirmed by amplifying the cphA gene by PCR. RESULTS: A total of 9 (40.9%) isolates were identified as Aeromonas hydrophila, 8 (36.4%) as Aeromonas veronii, and the remaining 5 (22.7%) isolates as Aeromonas caviae. Resistance to beta-lactams according to both the commercial microdilution and MIC gradient strips methods was: 36%-50% to imipenem; 4%-56% to cefotaxime, and 27%-56% to piperacillin/tazobactam. The agreement between results generated by the automated system and the diffusion antibiotic gradient strip was, for all 3 species, 68% for imipenem, 50% to cefotaxime, and 46% to piperacillin/tazobactam. No resistance to cotrimoxazole and ciprofloxacin was found by either of the two methods, although 22.7% of the strains were resistant to nalidixic acid. CONCLUSIONS: It is essential to identify the isolates of Aeromonas spp. at the species level, due to the fact that beta-lactam resistance is species- and method-dependent. The high rate of resistance to beta-lactam and quinolones reduce their application as empiric treatments for invasive infection by Aeromonas ssp

[The relevance of correct identification and interpretation of susceptibility testing of Aeromonas spp. bacteremia isolates]. / Influencia de la correcta identificación en la interpretación de las pruebas de sensibilidad en aislados de Aeromonas spp. productoras de bacteriemia.

OBJECTIVE: To assess the relevance of correct identification and interpretation of susceptibility testing of Aeromonas spp. bacteremia isolates using newly developed molecular methods in comparison to previous conventional methods. MATERIAL AND METHODS: The study included 22 patients with bacteremia due to Aeromonas hydrophila group, microbiologically characterized using the MicroScan system. Further identification to species level was performed by mass spectrometry, and confirmed by sequencing the rpoB gene. The MIC of imipenem, cefotaxime, piperacillin-tazobactam, ciprofloxacin and cotrimoxazole was studied using a commercial broth microdilution and antibiotic gradient strips with low and high inocula. Detection of carbapenemase production was performed using the modified Hodge test, and was confirmed by amplifying the cphA gene by PCR. RESULTS: A total of 9 (40.9%) isolates were identified as Aeromonas hydrophila, 8 (36.4%) as Aeromonas veronii, and the remaining 5 (22.7%) isolates as Aeromonas caviae. Resistance to beta-lactams according to both the commercial microdilution and MIC gradient strips methods was: 36%-50% to imipenem; 4%-56% to cefotaxime, and 27%-56% to piperacillin/tazobactam. The agreement between results generated by the automated system and the diffusion antibiotic gradient strip was, for all 3 species, 68% for imipenem, 50% to cefotaxime, and 46% to piperacillin/tazobactam. No resistance to cotrimoxazole and ciprofloxacin was found by either of the two methods, although 22.7% of the strains were resistant to nalidixic acid. CONCLUSIONS: It is essential to identify the isolates of Aeromonas spp. at the species level, due to the fact that beta-lactam resistance is species- and method-dependent. The high rate of resistance to beta-lactam and quinolones reduce their application as empiric treatments for invasive infection by Aeromonas ssp.

Gestante de 14 semanas con sepsis secundaria a corioamnionitis por Peptoniphilus harei / A pregnant woman at 14 weeks with sepsis caused by chorioamnionitis due to Peptoniphilus harei

Las corioamnionitis precoces suelen producirse vía ascendente a partir de una infección vaginal o bien tras técnicas invasivas sobre el útero. La vaginosis bacteriana es prevalente entre gestantes, pero la infección ascendente con corioamnionitis y sepsis es infrecuente, más aún tan precozmente como en la semana 14. Para prevenir las complicaciones de la vaginosis se ha propuesto su cribado, sin que exista actualmente evidencia de su beneficio, al menos en gestantes de bajo riesgo. Sí parece establecido que el riesgo de recidiva a pesar del tratamiento adecuado es alto, por lo se recomienda el seguimiento de la gestante (AU)

Early chorioamnionitis most often occurs as a result of ascending infection from the vagina or after invasive procedures on the uterus. Bacterial vaginosis is prevalent among pregnant women, but ascending infection with chorioamnionitis and sepsis is rare, especially as early as week 14. Screening has been proposed to avoid the complications of vaginosis, with no current evidence of benefit, at least in low-risk pregnant women. However, it is well established that the risk of recurrence is high, despite adequate treatment, and therefore monitoring is recommended in pregnant woman with vaginosis (AU)

Gestante de 14 semanas con sepsis secundaria a corioamnionitis por Peptoniphilus harei / A pregnant woman at 14 weeks with sepsis caused by chorioamnionitis due to Peptoniphilus harei

Las corioamnionitis precoces suelen producirse vía ascendente a partir de una infección vaginal o bien tras técnicas invasivas sobre el útero. La vaginosis bacteriana es prevalente entre gestantes, pero la infección ascendente con corioamnionitis y sepsis es infrecuente, más aún tan precozmente como en la semana 14. Para prevenir las complicaciones de la vaginosis se ha propuesto su cribado, sin que exista actualmente evidencia de su beneficio, al menos en gestantes de bajo riesgo. Sí parece establecido que el riesgo de recidiva a pesar del tratamiento adecuado es alto, por lo se recomienda el seguimiento de la gestante (AU)

Early chorioamnionitis most often occurs as a result of ascending infection from the vagina or after invasive procedures on the uterus. Bacterial vaginosis is prevalent among pregnant women, but ascending infection with chorioamnionitis and sepsis is rare, especially as early as week 14. Screening has been proposed to avoid the complications of vaginosis, with no current evidence of benefit, at least in low-risk pregnant women. However, it is well established that the risk of recurrence is high, despite adequate treatment, and therefore monitoring is recommended in pregnant woman with vaginosis (AU)