Comparison of Selected Phenotypic Features of Persistent and Sporadic Strains of Listeria monocytogenes Sampled from Fish Processing Plants

(1) Background: The main source of transmission of Listeria monocytogenes is contaminated food, e.g., fish and meat products and raw fruit and vegetables. The bacteria can remain for 13 years on machines in food processing plants, including fish plants. (2) Methods: A total of 720 swabs were collected from a salmon filleting line. The research material consisted of 62 (8.6%) L. monocytogenes isolates. Pulsed Field Gel Electrophoresis (PFGE) allowed detecting a pool of persistent strains. All persistent strains (n = 6) and a parallel group of strains collected sporadically (n = 6) were characterized by their ability to invade HT-29 cells, biofilm formation ability, and minimum bactericidal concentrations (MBC) of selected disinfectants. (3) Results: Among the obtained isolates, 38 genetically different strains were found, including 6 (15.8%) persistent strains. The serogroup 1/2a-3a represented 28 strains (73.7%), including the persistent ones. There were no significant differences in invasiveness between the persistent and sporadic strains. The persistent strains tolerated higher concentrations of the tested disinfectants, except for iodine-based compounds. The persistent strains initiated the biofilm formation process faster and formed it more intensively. (4) Conclusions: The presence of persistent strains in the food processing environment is a great challenge for producers to ensure consumer safety. This study attempts to elucidate the phenotypic characteristics of persistent L. monocytogenes strains

Effect of intimate hygiene fluids on the number of Listeria monocytogenes isolated from women

Introduction. Listeria monocytogenes is an etiological factor of listeriosis, widespread in the environment. The consequence of fetal infection in the second trimester of pregnancy in most cases is the death of the fetus or stillbirth.Material and methods. In this study, 7 strains of L. monocytogenes isolated from the vagina of women and the reference strain L. monocytogenes ATCC 19111 were used. The examined strains were treated with five commercially available intimate hygiene washes. The efficacy of the wash fluids used was based on the induced decrease in the number of bacteria expressed as a logarithmic colony-forming unit (CFU) × ml-1.Results. The study showed that probiotic fluid (pH = 3.5) decreased the number of bacteria by an average of 4.56 log CFU × ml-1, while wash fluid intended for pregnant and puerperal women (pH = 4.0) reduced the number of L. monocytogenes by an average of 1.55 log CFU × ml-1. Lower bactericidal efficacy was observed in the case of wash fluids intended for everyday use. The fluid containing marigold extract and the liquid with the addition of rice proteins and arnica extract decreased the number of L. monocytogenes by an average of 1.11 log CFU × ml-1, and the fluid with silver and copper nanoparticles by 1.14 log CFU × ml-1. Conclusions. Everyday use of intimate hygiene washes reduces the risk of urogenital infections in women and supports their treatment. Prevention with the use of probiotic wash solutions may reduce the number of vaginal infections caused by L. monocytogenes, which is especially important in the case of pregnant women because the number of patients diagnosed with listeriosis has increased

Effect of Lactobacillus spp. strains on the population of Listeria monocytogenes isolated from the human vagina

Introduction: The normal vaginal microbiota (mainly Lactobacillus spp.) affects the health of these areas. Bacterial vaginosis is a serious health problem among many women, especially dangerous for pregnant women. The study aimed to assess the impact of Lactobacillus spp. strains on the population of Listeria monocytogenes isolated from women. Materials and methods: The research material consisted of reference strains of Lactobacillus spp.: L. acidophilus (LAC), L. fermentum (LFE), L. gasseri (LGA), L. plantarum (LPL), the strain L. monocytogenes ATCC 19111 and 7 L. monocytogenes strains isolated from the vagina. Results: The highest antagonistic activity was shown for the mixed culture of all Lactobacillus strains (LACTO MIX) used in the experiment. Among the individual strains of Lactobacillus spp. strains, L. plantarum turned out to most effectively reduce L. monocytogenes number (reduction of 5.74 log CFU × ml-1). The least effective in inhibiting the growth of L. monocytogenes was the L. acidophilus strain (reduction of L. monocytogenes of a number of 2.21 log CFU × ml-1). Conclusions: The presence of Lactobacillus spp. in the genital tract limits the development of bacterial infections, which is an important aspect especially for pregnant women

Efficacy of Radiant Catalytic Ionization in Reduction of Enterococcus spp., Clostridioides difficile and Staphylococcus aureus in Indoor Air

(1) Background: An aerogenic way is one of main rout of spreading microorganisms (including antibiotic resistant), that cause healthcare-associated infections. The source of microorganisms in the air can be patients, personnel, visitors, outdoor air, hospital surfaces and equipment, and even sink drains. (2) Methods: The standardized suspensions (0.5 McFarland) of the examined strains (Enterococcus spp., Clostridioides difficile, Staphylococcus aureus) were nebulized in sterile chamber. Then the Induct 750 (ActivTek) device, generating RCI (radiant catalytic ionization) phenomenon, was used for 20 min. Next, the number of bacteria in the air was calculated using collision method. The percentage of reduction coefficient (R) was calculated. (3) Results: In case of enterococci, the R value was >90% and there are no statistically significant differences among tested strains. For C. difficile strains the R value range from 64–95%. The R value calculated for hypervirulent, antibiotic resistant CDI PCR 27 strain was statistically significantly lower than for other examined strains. For S. aureus non-MRSA the R value was 99.87% and for S. aurues MRSA the R value was 95.61%. (4) Conclusions: The obtained results indicate that the use of RCI may contribute to reducing the occurrence of dangerous pathogens in the air, and perhaps transmission and persistence in the hospital buildings environment