2026-07-21T17:17:16Zhttps://repisalud.isciii.es/rest/oai/request

oai:repisalud.isciii.es:20.500.12105/160472025-05-08T13:08:55Zcom_20.500.12105_2052com_20.500.12105_2051col_20.500.12105_19609col_20.500.12105_25179

00925njm 22002777a 4500 dc Amblar, Monica author Zaballos, Ángel author de la Campa, Adela G author 2022-12-17 PatAB is an ABC bacterial transporter that facilitates the export of antibiotics and dyes. The overexpression of patAB genes conferring efflux-mediated fluoroquinolone resistance has been observed in several laboratory strains and clinical isolates of Streptococcus pneumoniae. Using transformation and whole-genome sequencing, we characterized the fluoroquinolone-resistance mechanism of one S. pneumoniae clinical isolate without mutations in the DNA topoisomerase genes. We identified the PatAB fluoroquinolone efflux-pump as the mechanism conferring a low-level resistance to ciprofloxacin (8 µg/mL) and levofloxacin (4 µg/mL). Genetic transformation experiments with different amplimers revealed that the entire patA plus the 5'-terminus of patB are required for levofloxacin-efflux. By contrast, only the upstream region of the patAB operon, plus the region coding the N-terminus of PatA containing the G39D, T43A, V48A and D100N amino acid changes, are sufficient to confer a ciprofloxacin-efflux phenotype, thus suggesting differences between fluoroquinolones in their binding and/or translocation pathways. In addition, we identified a novel single mutation responsible for the constitutive and ciprofloxacin-inducible upregulation of patAB. This mutation is predicted to destabilize the putative rho-independent transcriptional terminator located upstream of patA, increasing transcription of downstream genes. This is the first report demonstrating the role of the PatAB transporter in levofloxacin-efflux in a pneumoccocal clinical isolate. Antibiotics (Basel). 2022 Dec 17;11(12):1837. 10.3390/antibiotics11121837 2079-6382 Antibiotics (Basel, Switzerland) 36551495 http://hdl.handle.net/20.500.12105/16047 PatAB Streptococcus pneumoniae Efflux-pump Fluoroquinolone-resistance Levofloxacin-efflux Role of PatAB Transporter in Efflux of Levofloxacin in Streptococcus pneumoniae