Evaluation of culture conditions for sewage-based surveillance of antibiotic resistance in Klebsiella pneumoniae

Julián Bobis Camacho; Johanna Nilsson; Dan Göran Joakim Larsson; Carl-Fredrik Flach

doi:10.1016/j.jgar.2024.03.005

Evaluation of culture conditions for sewage-based surveillance of antibiotic resistance in Klebsiella pneumoniae

J Glob Antimicrob Resist. 2024 Mar 27:37:122-128. doi: 10.1016/j.jgar.2024.03.005. Online ahead of print.

Authors

Julián Bobis Camacho¹, Johanna Nilsson¹, Dan Göran Joakim Larsson¹, Carl-Fredrik Flach²

Affiliations

¹ Centre for Antibiotic Resistance Research in Gothenburg (CARe), University of Gothenburg, Gothenburg, Sweden; Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
² Centre for Antibiotic Resistance Research in Gothenburg (CARe), University of Gothenburg, Gothenburg, Sweden; Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden. Electronic address: carl-fredrik.flach@microbio.gu.se.

PMID: 38552871
DOI: 10.1016/j.jgar.2024.03.005

Abstract

Background: Recent studies have shown promise in predicting clinical antibiotic resistance rates from sewage data. Few have focused on Klebsiella pneumoniae, despite its virulence and importance as carrier of antibiotic resistance. Several media have been suggested for the isolation of K. pneumoniae from complex samples. However, comprehensive evaluations of culture protocols for isolation of K. pneumoniae from sewage are lacking.

Methods: Here, influent samples from a major Swedish sewage treatment plant were used to evaluate ten culture conditions in parallel: cultivation on Brilliant green containing Inositol-Nitrate-Deoxycholate agar (BIND), Bruce agar, Klebsiella ChromoSelect Selective agar®, MacConkey-Inositol-Carbenicillin, or Simmons Citrate Agar with Inositol (SCAI) incubated at either 37°C or 42°C for 44 h. The culture conditions were compared based on colony counts of presumed K. pneumoniae and identification precision assessed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Results: The sensitivity was lowest for BIND, whereas it was similar for the other media irrespective of incubation temperature. For four media, a better precision was observed after incubation at 42°C compared to 37°C, to a large extent explained by a lower frequency of captured Klebsiella oxytoca. SCAI incubated at 42°C showed the highest precision (84.4%). By combining this protocol with subsequent antibiotic resistance screening of collected isolates, low resistance rates in sewage K. pneumoniae were revealed, potentially reflecting the local resistance landscape.

Conclusion: When combined with downstream analyses, SCAI incubated at 42°C could be a valuable culture protocol for sewage-based studies on various aspects of K. pneumoniae epidemiology including antibiotic resistance prevalence.

Keywords: Comparison; Culture protocol; SCAI; Temperature; Wastewater; Wastewater-based epidemiology.