Listeria monocytogenes strains (n ‫؍‬ 117) were screened for the presence of stress survival islet 1 (SSI-1). SSI-1؉ strains (32.5%) belonged mainly to serotypes 1/2c, 3b, and 3c. All sequence type 121 (ST-121) strains included (n ‫؍‬ 7) possessed homologues to Listeria innocua genes lin0464 and lin0465 instead of SSI-1.The genus Listeria comprises eight species:and the newly described L. rocourtiae and L. marthii (7,11,18). From a human perspective, the food-borne pathogen L. monocytogenes is the most important species of this genus. Recently, a stress survival islet (stress survival islet 1 [SSI-1]) has been identified in L. monocytogenes (29). Deletion mutants showed impaired growth at low pH and high salt concentrations. The islet was present in about 50% of tested L. monocytogenes strains, mainly those not belonging to serogroup 4. According to the sequence of L. monocytogenes EGD-e (serotype 1/2a), the islet contains five genes, lmo0444, lmo0445, lmo0446 (pva), lmo0447 (gadD1), and lmo0448 (gadT1), positioned between two genes highly conserved across different Listeria spp. An open reading frame (ORF) transcribed in the opposite direction is present at this location in L. monocytogenes strains without the islet (e.g., strain F2365, serotype 4b), and in L. innocua CLIP 11262, two genes transcribed in opposite directions (lin0464 and lin0465) are present at the same location (29). L. welshimeri SLCC 5334 does not contain any genes at this position. In L. seeligeri SLCC 3954, this region was similar to that in L. welshimeri SLCC 5334, with no open reading frame and with small differences in the lengths of the intergenic region, i.e., 281 bp (L. welshimeri FN557490) and 166 bp (L. seeligeri AM263198). There was 63% identity between a 46-bp stretch at the 5Ј end in L. welshimeri and that in L. seeligeri, both of which were followed by an L. welshimerispecific portion of 112 bp and a 123-bp stretch at the 3Ј end with 73.2% identity.In the present study, a collection of 117 L. monocytogenes strains, including isolates from cheese dairies, meat and meat products, fish, and veterinary and human infections, was screened by PCR for the presence of SSI-1 (Table 1; also see Table S1 in the supplemental material) (29). Serotypes were determined by classical serotyping and by a multiplex PCR method for grouping strains into four major serotype-related groups (9, 31). The predicted 9.7-kbp (SSI-1 ϩ ) and 1.1-kbp (SSI-1 Ϫ ) fragments were observed in 32.5% and 61.5% of strains, respectively ( Fig. 1; Table 2). SSI-1 was present in the majority of 1/2c, 3b, and 3c strains tested but in only one strain each of serotypes 4a and 4b. A single serotype 4c strain was included in the survey, and it contained SSI-1. The majority of serotype 4b, 1/2a, and 4a strains, as well as all strains with ambiguous serotype 4d or 4e, lacked SSI-1. Earlier findings suggest that SSI-1 is more prevalent in non-serogroup 4 strains, which was confirmed by our results: 50% of non-serogroup 4 strains but only 7.5% of serogroup 4 strains contained SS...

BackgroundSymptoms of mental stress are a hallmark of the COVID-19 pandemic. We hypothesized that just testing for COVID-19 could act as an effective stressor for persisting symptoms of mental distress including posttraumatic stress disorder. Our study aimed to determine whether personal beliefs on individual control and competence (locus of control, LoC) correlate with symptoms of mental distress and positive screening for post-traumatic stress disorder during a 9-month observational period.MethodsBetween March and December 2021, we applied online versions of the Questionnaire on Competence and Control Expectations (FKK), the Depression, Anxiety, and Stress Score (DASS), the Short Screening Scale for DSM-IV Posttraumatic Stress Disorder (PTSD), and a medical history questionnaire for COVID-19 symptoms (visit 1). 48 hours after negative COVID-19 testing, DASS was repeated to address relief effects on mental distress (visit 2). Following 90 days (visit 3), development of mental distress was addressed by a combination of DASS and PTSD, while the possible long-term manifestation of PTSD was evaluated 9 months later (visit 4).ResultsAt visit 1, 7.4 percent of the total sample (n = 867) demonstrated a positive screening for PTSD, while after nine months (at visit 4), 8.9 percent of the remaining sample (n = 204) had positive screening results. The mean age was 36.2 years; 60.8% were women, 39.2% men. In contrast to individuals with negative PTSD screening, these participants demonstrated a significantly different LoC personality profile. This was confirmed by the results of both DASS and the COVID-19 medical history questionnaire.ConclusionFollowing testing for COVID-19, individuals with positive long-term PTSD screening present with significantly different personality traits than those w/o suggesting that self-confidence and effective control over one’s own actions serve as a protective function against mental distress.