High-level quinolone resistance is associated with the overexpression of smeVWX in Stenotrophomonas maltophilia clinical isolates

AbstractStenotrophomonas maltophilia is the only known bacterium in which quinolone-resistant isolates do not present mutations in the genes encoding bacterial topoisomerases. The expression of the intrinsic quinolone resistance elements smeDEF, smeVWX and Smqnr was analysed in 31 clinical S. maltophilia isolates presenting a minimum inhibitory concentration (MIC) range to ciprofloxacin between 0.5 and > 32 μg/mL; 11 (35.5%) overexpressed smeDEF, 2 (6.5%) presenting the highest quinolone MICs overexpressed smeVWX and 1 (3.2%) overexpressed Smqnr. Both strains overexpressing smeVWX presented changes at the Gly266 position of SmeRv, the repressor of smeVWX. Changes at the same position were previously observed in in vitro selected S. maltophilia quinolone-resistant mutants, indicating this amino acid is highly relevant for the activity of SmeRv in repressing smeVWX expression. For the first time SmeVWX overexpression is associated with quinolone resistance of S. maltophilia clinical isolates

Peritonitis bacteriana espontánea por Listeria monocytogenes: presentación de ocho casos (1992- 2017) y revisión de la literatura

Objective: Spontaneous bacterial peritonitis (SBP) is a frequent and severe entity in patients with cirrhosis or ascites due to other causes. However, Listeria monocytogenes is a microorganism that has been scarcely identified as a causative agent of SBP. Methods: In this study, a descriptive analysis of cases of L. monocytogenes SBP was carried out in our center for 26 years (1992-2017). Results: A total of eight patients were diagnosed, with an average age of 58 years, with no differences in sex distribution and all of them were community acquired cases. Half of the patients had underlying liver disease, two of them active malignancies; one was undergoing continuous ambulatory peritoneal dialysis and the last one with hypertensive heart disease. Six (75%) of the patients received a third-generation cephalosporin as empirical treatment. The clinical course was favorable after receiving directed antibiotic treatment in five (62.5%) of the patients. However, three of them, under the age of 59, died. Serotyping of L. monocytogenes isolates revealed that half of them were serovar 4, two 1 / 2a and the remaining one 1 / 2c. All strains were susceptible to ampicillin, meropenem, erythromycin and cotrimoxazole. Conclusions: We conclude by emphasizing the importance of taking this etiology into account in patients with underlying liver disease and with clinical or laboratory data suggesting SBP, mainly due to the need for specific antibiotic treatment different from conventionally empirically used

ESICM LIVES 2016: part two : Milan, Italy. 1-5 October 2016.

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