AIMS: Listeria monocytogenes nisin resistance increases when first exposed to NaCl and other stresses, such as low pH. In addition to environmental stressors, specific genomic elements can confer nisin resistance, such as the stress survival islet (SSI-1). As SSI-1 is variably present among L. monocytogenes strains, we wanted to determine if SSI-1 was associated with salt-induced nisin resistance. METHODS AND RESULTS: The presence of SSI-1 was determined using PCR for 48 strains of L. monocytogenes. When combined with multilocus sequence typing data, we found that the distribution of SSI-1 is clonal, where strains from clonal complexes (CC) 2, 6 and 11 do not have SSI-1, while strains from CCs 3, 5, 7 and 9 contain SSI-1. The impact of SSI-1 on salt-induced nisin resistance was dependent on CC. The average log decrease after 24 h of exposure to nisin at 7°C under salt-inducing conditions was 2·6 ± 1·1 for CC 9 strains and 2·3 ± 0·7 for CC 11 strains, which had significantly lower survival compared to the other CCs, such as 1·3 ± 0·3 for CC 6. Deletion of SSI-1 from a CC 7 strain demonstrated the role SSI-1 plays in salt-induced nisin resistance, as the deletion mutant had lower resistance compared to the parent strain. CONCLUSIONS: These data suggest that inducible nisin resistance in L. monocytogenes can be influenced by environmental conditions as well as the genetic composition of the strain, which should be considered when selecting control measures for ready-to-eat foods. SIGNIFICANCE AND IMPACT OF THE STUDY: The foodborne pathogen L. monocytogenes can grow in suboptimal conditions, including low temperature and high osmolarity, which makes it a safety concern for ready-to-eat foods. When using antimicrobial peptide inhibitors such as nisin, it is important to understand how food components can impact antimicrobial resistance across the genetic diversity of L. monocytogenes.
AIMS: Listeria monocytogenes nisin resistance increases when first exposed to NaCl and other stresses, such as low pH. In addition to environmental stressors, specific genomic elements can confer nisin resistance, such as the stress survival islet (SSI-1). As SSI-1 is variably present among L. monocytogenes strains, we wanted to determine if SSI-1 was associated with salt-induced nisin resistance. METHODS AND RESULTS: The presence of SSI-1 was determined using PCR for 48 strains of L. monocytogenes. When combined with multilocus sequence typing data, we found that the distribution of SSI-1 is clonal, where strains from clonal complexes (CC) 2, 6 and 11 do not have SSI-1, while strains from CCs 3, 5, 7 and 9 contain SSI-1. The impact of SSI-1 on salt-induced nisin resistance was dependent on CC. The average log decrease after 24 h of exposure to nisin at 7°C under salt-inducing conditions was 2·6 ± 1·1 for CC 9 strains and 2·3 ± 0·7 for CC 11 strains, which had significantly lower survival compared to the other CCs, such as 1·3 ± 0·3 for CC 6. Deletion of SSI-1 from a CC 7 strain demonstrated the role SSI-1 plays in salt-induced nisin resistance, as the deletion mutant had lower resistance compared to the parent strain. CONCLUSIONS: These data suggest that inducible nisin resistance in L. monocytogenes can be influenced by environmental conditions as well as the genetic composition of the strain, which should be considered when selecting control measures for ready-to-eat foods. SIGNIFICANCE AND IMPACT OF THE STUDY: The foodborne pathogen L. monocytogenes can grow in suboptimal conditions, including low temperature and high osmolarity, which makes it a safety concern for ready-to-eat foods. When using antimicrobial peptide inhibitors such as nisin, it is important to understand how food components can impact antimicrobial resistance across the genetic diversity of L. monocytogenes.
Authors: Paolo Stincone; Flávio Fonseca Veras; Giuseppe Micalizzi; Danilo Donnarumma; Gaetano Vitale Celano; Daniel Petras; Maria de Angelis; Luigi Mondello; Adriano Brandelli Journal: Cell Mol Life Sci Date: 2022-04-28 Impact factor: 9.261
Authors: Susanne Raschle; Roger Stephan; Marc J A Stevens; Nicole Cernela; Katrin Zurfluh; Francis Muchaamba; Magdalena Nüesch-Inderbinen Journal: Sci Rep Date: 2021-04-27 Impact factor: 4.379
Authors: Anna Sophia Harrand; Balamurugan Jagadeesan; Leen Baert; Martin Wiedmann; Renato H Orsi Journal: Appl Environ Microbiol Date: 2020-03-02 Impact factor: 4.792