Evaluation of phenotypical and genotypical methods for the identification and typing of Stenotrophomonas maltophilia isolated from a pharmaceutical facility

• Published in: Journal of applied microbiology Vol. 134; no. 10
• Main Authors: de Miranda, Rebeca Vitória da Silva Lage, Monteiro, Giovanna Merrelho, da Costa, Luciana Veloso, dos Santos, Milena Cristina Silva, dos Reis, Cristhiane Moura Falavina, Braga, Lygia Maria Paulo da Silva, Forsythe, Stephen James, Villas Bôas, Maria Helena Simões, Brandão, Marcelo Luiz Lima
• Format: Journal Article
• Language: English
• Published: 04-10-2023
• ISSN: 1365-2672; 1365-2672
• DOI: 10.1093/jambio/lxad236

Abstract
Aims
Evaluate methods for identification and typing of Stenotrophomonas maltophilia isolated from a pharmaceutical facility.
Methods and results
From 270 S. maltophilia strains identified by VITEK®2, 40 were selected and submitted to MALDI TOF-MS, 16S and 23S rRNA gene analysis, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR), and an antimicrobial susceptibility profile. 16S rRNA sequencing was able to identify 39 (97.5%) strains as Stenotrophomonas spp. and one (2.5%) as Luteimonas huabeiensis. MALDI TOF-MS identified 37 (92.5%) strains as S. maltophilia, and three (7.5%) were not identified. PCR targeting 23S rRNA yielded a positive result for 39 (97.5%) strains. However, after sequencing, two strains were identified as Stenotrophomonas rhizophila, showing false-positive results. The confirmed S. maltophilia strains (n = 37) showed 35 distinct ERIC-PCR profiles and exhibited sensitivity to minocycline and levofloxacin, and six (16.3%) showed intermediate resistance to sulfamethoxazole-trimethoprim.
Conclusion
Matrix-assisted laser desorption lonization-time of flight mass spectrometry (MALDI-TOF MS) was a satisfactory methodology for the identification of S. maltophilia, but expansion of the database is necessary for the identification of other species. 16S rDNA sequencing showed low resolution for Stenotrophomonas species differentiation. PCR targeting 23S rRNA could not differentiate S. maltophilia from S. rhizophila. ERIC-PCR was shown to be a useful tool for the microbial source tracking of S. maltophilia.