Antibiotics (Feb 2024)

Outbreak of <i>Pseudomonas aeruginosa</i> High-Risk Clone ST309 Serotype O11 Featuring <i>bla</i><sub>PER-1</sub> and <i>qnrVC6</i>

  • Romina Papa-Ezdra,
  • Matilde Outeda,
  • Nicolás F. Cordeiro,
  • Lucía Araújo,
  • Pilar Gadea,
  • Virginia Garcia-Fulgueiras,
  • Verónica Seija,
  • Inés Bado,
  • Rafael Vignoli

DOI
https://doi.org/10.3390/antibiotics13020159
Journal volume & issue
Vol. 13, no. 2
p. 159

Abstract

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Pseudomonas aeruginosa is a leading cause of hospital-acquired infections worldwide. Biofilm production, antibiotic resistance, and a wide range of virulence factors contribute to their persistence in nosocomial environments. We describe an outbreak caused by a multidrug-resistant P. aeruginosa strain in an ICU. Antibiotic susceptibility was determined and blaPER-1 and qnrVC were amplified via PCR. Clonality was determined using PFGE and biofilm formation was studied with a static model. A combination of antibiotics was assessed on both planktonic cells and biofilms. WGS was performed on five isolates. All isolates were clonally related, resistant to ceftazidime, cefepime, amikacin, and ceftolozane-tazobactam, and harbored blaPER-1; 11/19 possessed qnrVC. Meropenem and ciprofloxacin reduced the biofilm biomass; however, the response to antibiotic combinations with rifampicin was different between planktonic cells and biofilms. WGS revealed that the isolates belonged to ST309 and serotype O11. blaPER-1 and qnrVC6 were associated with a tandem of ISCR1 as part of a complex class one integron, with aac(6′)-Il and ltrA as gene cassettes. The structure was associated upstream and downstream with Tn4662 and flanked by direct repeats, suggesting its horizontal mobilization capability as a composite transposon. ST309 is considered an emerging high-risk clone that should be monitored in the Americas.

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