Assessing the Contributions of the LiaS Histidine Kinase to the Innate Resistance of Listeria monocytogenes to Nisin, Cephalosporins, and Disinfectants

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>The<jats:named-content content-type="genus-species">Listeria monocytogenes</jats:named-content>LiaSR two-component system (2CS) encoded by<jats:italic>lmo1021</jats:italic>and<jats:italic>lmo1022</jats:italic>plays an important role in resistance to the food preservative nisin. A nonpolar deletion in the histidine kinase-encoding component (Δ<jats:italic>liaS</jats:italic>) resulted in a 4-fold increase in nisin resistance. In contrast, the Δ<jats:italic>liaS</jats:italic>strain exhibited increased sensitivity to a number of cephalosporin antibiotics (and was also altered with respect to its response to a variety of other antimicrobials, including the active agents of a number of disinfectants). This pattern of increased nisin resistance and reduced cephalosporin resistance in<jats:named-content content-type="genus-species">L. monocytogenes</jats:named-content>has previously been associated with mutation of a second histidine kinase, LisK, which is a predicted regulator of<jats:italic>liaS</jats:italic>and a penicillin binding protein encoded by<jats:italic>lmo2229</jats:italic>. We noted that<jats:italic>lmo2229</jats:italic>transcription is increased in the Δ<jats:italic>liaS</jats:italic>mutant and in a Δ<jats:italic>liaS</jats:italic>Δ<jats:italic>lisK</jats:italic>double mutant and that disruption of<jats:italic>lmo2229</jats:italic>in the Δ<jats:italic>liaS</jats:italic>Δ<jats:italic>lisK</jats:italic>mutant resulted in a dramatic sensitization to nisin but had a relatively minor impact on cephalosporin resistance. We anticipate that further efforts to unravel the complex mechanisms by which LiaSR impacts on the antimicrobial resistance of<jats:named-content content-type="genus-species">L. monocytogenes</jats:named-content>could facilitate the development of strategies to increase the susceptibility of the pathogen to these agents.</jats:p>

Lantibiotic Resistance

“…The role of LiaRS in L. monocytogenes has been investigated (59,143,144). LiaRS-mediated signal transduction is also negatively regulated by LiaF, in a fashion similar to that described for B. subtilis (143).…”

“…In L. monocytogenes, however, the expression of 27 genes (143), including a PBP gene (57) and telA, which encodes a protein involved in toxic ion resistance (145), is also regulated. Collins et al (144) reported that a ⌬liaS strain grew more successfully than the corresponding wild type in the presence of nisin. A mutant lacking another histidine kinase, the ⌬lisK mutant, which also has a nisin resistance phenotype, was previously reported to alter liaS and PBP expression.…”

“…With this in mind, the nisin resistances of 3 mutants, the ⌬liaS, ⌬liaS ⌬lisK, and ⌬lisK mutants, were compared, and it was discovered that the ⌬lisK mutant was 2-fold more resistant than the wild type and that the ⌬liaS and ⌬liaS ⌬lisK mutants were another 2-fold more resistant. On the basis of the nisin resistance phenotypes of these mutants, it was postulated that these phenotypes were attributable to the increased production of the corresponding PBP, whose expression was also increased in the ⌬liaS mutant (144). In contrast, mutation of the corresponding response regulator (⌬liaR mutation) in seven wild-type strains of L. monocytogenes resulted in an average decrease in cell density of 5.2 Ϯ 0.7 log 10 CFU ml Ϫ1 after 24 h for the 7 ⌬liaR strains compared to the wild type on exposure to nisin (146).…”

Synthesis and Evaluation of the Antimicrobial Activity of Dodecyl trimethyl ammonium and N-(N, N-dimethylamino) Propyl Glucosylamine

“…Furthermore, future effectiveness of antimicrobial therapy is somewhat in doubt since various microorganisms are becoming more resistant to the existing antimicrobial agents [1][2][3][4][5][6] . Therefore, it is the responsibility of scientists to work hard and to find out environment friendly active compounds which can be used in this struggling.…”

“…These harmful microorganisms can be major source of food toxi-infection leading to different human diseases. For instance Salmonella and Listeria species, very resistant mircroorganisms at different conditions used for food preservation, can lead to salmonellose and listeriose, two known human fatal diseases [1][2][3][4][5][6] .…”