Factors influencing environmental sampling recovery of healthcare pathogens from non-porous surfaces with cellulose sponges

PLoS One. 2022 Jan 13;17(1):e0261588. doi: 10.1371/journal.pone.0261588. eCollection 2022.

Abstract

Results from sampling healthcare surfaces for pathogens are difficult to interpret without understanding the factors that influence pathogen detection. We investigated the recovery of four healthcare-associated pathogens from three common surface materials, and how a body fluid simulant (artificial test soil, ATS), deposition method, and contamination levels influence the percent of organisms recovered (%R). Known quantities of carbapenemase-producing KPC+ Klebsiella pneumoniae (KPC), Acinetobacter baumannii, vancomycin-resistant Enterococcus faecalis, and Clostridioides difficile spores (CD) were suspended in Butterfield's buffer or ATS, deposited on 323cm2 steel, plastic, and laminate surfaces, allowed to dry 1h, then sampled with a cellulose sponge wipe. Bacteria were eluted, cultured, CFU counted and %R determined relative to the inoculum. The %R varied by organism, from <1% (KPC) to almost 60% (CD) and was more dependent upon the organism's characteristics and presence of ATS than on surface type. KPC persistence as determined by culture also declined by >1 log10 within the 60 min drying time. For all organisms, the %R was significantly greater if suspended in ATS than if suspended in Butterfield's buffer (p<0.05), and for most organisms the %R was not significantly different when sampled from any of the three surfaces. Organisms deposited in multiple droplets were recovered at equal or higher %R than if spread evenly on the surface. This work assists in interpreting data collected while investigating a healthcare infection outbreak or while conducting infection intervention studies.

MeSH terms

  • Acinetobacter baumannii / isolation & purification
  • Bacteria / isolation & purification*
  • Bandages / microbiology*
  • Cellulose / chemistry*
  • Clostridioides difficile / isolation & purification
  • Humans
  • Klebsiella pneumoniae / isolation & purification
  • Plastics / chemistry
  • Specimen Handling / methods*
  • Steel / chemistry
  • Surface Properties
  • Vancomycin-Resistant Enterococci / isolation & purification

Substances

  • Plastics
  • Steel
  • Cellulose

Grants and funding

the authors received no specific funding for this work.