2026. Phenotypic and Molecular Characterization of Drug Resistance and Biofilm Production in Stenotrophomonas maltophilia obtained in a ten-year period from a Mexican Hospital
Session: Poster Abstract Session: Diagnostics: Biomarkers and Novel Approaches
Saturday, October 6, 2018
Room: S Poster Hall
  • IDWeek 2018 Stenotrophomonas.pdf (646.9 kB)
  • Background: Stenotrophomonas maltophilia is an emerging drug-resistant opportunistic pathogen related with health care associated infections. The aim was to perform a phenotypic and molecular characterization of drug resistance and biofilm formation in S. maltophilia obtained in a ten-year period from a Mexican Hospital.

    Methods: S. maltophilia isolates from a ten-year period from a tertiary care hospital in Mexico were identified by MALDI-TOF MS. Antimicrobial susceptibility was determined by the broth microdilution method. Drug resistance-associated genes were analyzed by PCR. Biofilm formation and its composition was assessed by crystal violet staining, and detachment assays, respectively. Biofilm production-associated genes were analyzed by PCR. MALDI-TOF mass spectra patterns were analyzed to search markers of drug resistance and biofilm production using the ClinProTools software.

    Results: In the ten-year study period, 258 S. maltophilia isolates were identified, with high resistance detected for ceftazidime (48.4%), cefepime (31.6%), ciprofloxacin (25.0%), trimethoprim-sulfamethoxazole (18.8%), and lower resistance to chloramphenicol (13.6%) and levofloxacin (2.2%). Drug resistance was not associated to the presence of the sul1 (4.1%), sul2 (0.5%), sul3 (0.0%) or ISCR (0.0%) genes. Overexpression of the SmeABC efflux pump was associated to higher drug resistance (p<0.05). Overall, 97.7% isolates were biofilm producers, i.e., 41.7% were strong producers; 32.0% were moderate, and 26.2% were weak producers. Biofilm composition analysis showed similar percentages for carbohydrates, proteins and DNA in all isolates (36.0%, 39.7% and 40.9% respectively). Biofilm associated genes fsnR, rmlA, rpfF, xanB and spgM were detected in 94.0%, 75.3%, 28.6%, 17.2% and 0.0% of isolates, respectively. Four potential biomarker peaks were detected in rmlA positive biofilm-producing isolates (p<0.05).

    Conclusion: Most of S. maltophilia clinical isolates showed high antimicrobial resistance levels and were able to produce biofilm. Biofilm biomass composition of these isolates showed a similar proportion of polysaccharides, proteins, and DNA. The presence of the rmlA gene was associated with biofilm production. Four potential markers of the presence of the biofilm production-associated rmlA gene were detected by mass spectrometry.

    Samantha Flores-Treviño, PhD1, Rayo Morfin-Otero, PhD2, Óscar Manuel Alonso-Ambriz, Bachelor3, Gabriela Aimee Salazar-Mata, Bachelor3, Adrian Camacho-Ortiz, MD, PhD4, Licet Villarreal-Treviño, PhD3, Eduardo Rodríguez-Noriega, MD2, Héctor Jesús Maldonado-Garza, MD, PhD1 and Elvira Garza-González, PhD1, (1)Hospital Universitario "Dr. José Eleuterio González". Universidad Autónoma de Nuevo León, Monterrey, Mexico, (2)Hospital Civil de Guadalajara, Guadalajara, Mexico, Guadalajara, Mexico, (3)Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Monterrey, Mexico, (4)Infectious Diseases, Hospital Universitario "Dr. José Eleuterio González". Universidad Autónoma de Nuevo León, Monterrey, Mexico


    S. Flores-Treviño, None

    R. Morfin-Otero, None

    Ó. M. Alonso-Ambriz, None

    G. A. Salazar-Mata, None

    A. Camacho-Ortiz, None

    L. Villarreal-Treviño, None

    E. Rodríguez-Noriega, None

    H. J. Maldonado-Garza, None

    E. Garza-González, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.