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BMC Infectious Diseases Jun 2021Listeria monocytogenes (LM) has come to be a major public health issue of at-risk groups, causing high morbidity and mortality. Despite this data, studies are very...
BACKGROUND
Listeria monocytogenes (LM) has come to be a major public health issue of at-risk groups, causing high morbidity and mortality. Despite this data, studies are very limited in developing countries like Ethiopia. Thus, we aimed to isolate and characterize LM in terms of antibiogram and biofilm formation among pregnant women with fever, women with a history of spontaneous abortion, women with a history of fetal loss, and women with preterm delivery at Jimma University Medical Center (JUMC), southwest Ethiopia.
METHODS
A cross-sectional study was done among 144 women from June to August 2019. Isolates were tested for antibiotic susceptibility and biofilm formation using disc diffusion and microtiter plate method, respectively. Data were collected using a structured questionnaire, entered into Epidata 3.1 and logistic regression was done by SPSS v25.0.
RESULTS
LM was isolated in 8 (5.56%) of 144 screened women. The isolation rate of LM was relatively higher among women with a history of fetal loss (9.7%), followed by women with preterm delivery (6.25%). One of the six cord blood was positive for LM, indicating that the transplacental transmission rate at JUMC was 16.7%. More than 2% of women with an ongoing pregnancy were found to have LM septicemia, which could hurt their fetus. All of the isolates tested were susceptible to Ampicillin. However, all of the isolates were resistant to Penicillin and Meropenem and were biofilm producers.
CONCLUSIONS
The high magnitude of pregnancy-related listeriosis in the current study setting appears that implementation of educational programs targeting risk reduction and more studies to identify sources of LM are warranted. The choice of antibiotics should be after susceptibility testing.
Topics: Academic Medical Centers; Anti-Bacterial Agents; Cross-Sectional Studies; Ethiopia; Female; Humans; Listeria monocytogenes; Listeriosis; Microbial Sensitivity Tests; Pregnancy; Pregnancy Complications, Infectious
PubMed: 34118865
DOI: 10.1186/s12879-021-06254-w -
Journal of Bacteriology Jan 2021Lysozyme is an important component of the innate immune system. It functions by hydrolyzing the peptidoglycan (PG) layer of bacteria. The human pathogen is...
Lysozyme is an important component of the innate immune system. It functions by hydrolyzing the peptidoglycan (PG) layer of bacteria. The human pathogen is intrinsically lysozyme resistant. The peptidoglycan -deacetylase PgdA and -acetyltransferase OatA are two known factors contributing to its lysozyme resistance. Furthermore, it was shown that the absence of components of an ABC transporter, referred to here as EslABC, leads to reduced lysozyme resistance. How its activity is linked to lysozyme resistance is still unknown. To investigate this further, a strain with a deletion in , coding for a membrane component of the ABC transporter, was constructed in strain 10403S. The mutant showed a 40-fold reduction in the MIC to lysozyme. Analysis of the PG structure revealed that the mutant produced PG with reduced levels of -acetylation. Using growth and autolysis assays, we showed that the absence of EslB manifests in a growth defect in media containing high concentrations of sugars and increased endogenous cell lysis. A thinner PG layer produced by the mutant under these growth conditions might explain these phenotypes. Furthermore, the mutant had a noticeable cell division defect and formed elongated cells. Microscopy analysis revealed that an early cell division protein still localized in the mutant, indicating that a downstream process is perturbed. Based on our results, we hypothesize that EslB affects the biosynthesis and modification of the cell wall in and is thus important for the maintenance of cell wall integrity. The ABC transporter EslABC is associated with the intrinsic lysozyme resistance of However, the exact role of the transporter in this process and in the physiology of is unknown. Using different assays to characterize an deletion strain, we found that the absence of EslB affects not only lysozyme resistance but also endogenous cell lysis, cell wall biosynthesis, cell division, and the ability of the bacterium to grow in media containing high concentrations of sugars. Our results indicate that EslB is, by means of a yet-unknown mechanism, an important determinant for cell wall integrity in .
Topics: Bacterial Proteins; Cell Wall; Gene Deletion; Gene Expression Regulation; Listeria monocytogenes; Muramidase; Peptidoglycan; Virulence
PubMed: 33229460
DOI: 10.1128/JB.00553-20 -
Molecular Microbiology Dec 2021Listeria monocytogenes is a food-borne bacterium that causes gastroenteritis, meningitis, or abortion. L. monocytogenes induces its internalization (entry) into human... (Review)
Review
Listeria monocytogenes is a food-borne bacterium that causes gastroenteritis, meningitis, or abortion. L. monocytogenes induces its internalization (entry) into human cells and either spreads laterally in tissues or transcytoses to traverse anatomical barriers. In this review, we discuss mechanisms by which five structurally related proteins of the "internalin" family of L. monocytogenes (InlA, InlB, InlC, InlF, and InlP) interact with distinct host receptors to promote infection of human cells and/or crossing of the intestinal, blood-brain, or placental barriers. We focus on recent results demonstrating that the internalin proteins InlA, InlB, and InlC exploit exocytic pathways to stimulate transcytosis, entry, or cell-to-cell spread, respectively. We also discuss evidence that InlA-mediated transcytosis contributes to traversal of the intestinal barrier, whereas InlF promotes entry into endothelial cells to breach the blood-brain barrier. InlB also facilitates the crossing of the blood-brain barrier, but does so by extending the longevity of infected monocytes that may subsequently act as a "Trojan horse" to transfer bacteria to the brain. InlA, InlB, and InlP each contribute to fetoplacental infection by targeting syncytiotrophoblast or cytotrophoblast layers of the placenta. This work highlights the diverse functions of internalins and the complex mechanisms by which these structurally related proteins contribute to disease.
Topics: Animals; Bacterial Proteins; Humans; Listeria monocytogenes; Listeriosis; Membrane Proteins; Transcytosis
PubMed: 34704304
DOI: 10.1111/mmi.14836 -
Toxins Jun 2020is among the best-characterized intracellular pathogens. Its virulence factors, and the way they interfere with host cells to hijack host functions and promote the...
is among the best-characterized intracellular pathogens. Its virulence factors, and the way they interfere with host cells to hijack host functions and promote the establishment and dissemination of the infection, have been the focus of multiple studies over the last 30 years. During cellular infection, was shown to induce host DNA damage and delay the host cell cycle to its own benefit. However, whether the cell cycle stage would interfere with the capacity of to infect human cultured cell lines was never assessed. We found here that preferentially infects cultured cells in G2/M phases. Inside G2/M cells, the bacteria lead to an increase in the overall mitosis duration by delaying the mitotic exit. We showed that infection causes a sustained activation of the spindle assembly checkpoint, which we correlated with the increase in the percentage of misaligned chromosomes detected in infected cells. Moreover, we demonstrated that chromosome misalignment in -infected cells required the function of two virulence factors, ActA and InlC. Our findings show the pleiotropic role of virulence factors and their cooperative action in successfully establishing the cellular infection.
Topics: Bacterial Proteins; Caco-2 Cells; Chromosome Segregation; G2 Phase Cell Cycle Checkpoints; Host-Pathogen Interactions; Humans; Listeria monocytogenes; Listeriosis; M Phase Cell Cycle Checkpoints; Membrane Proteins; Mitosis; Virulence; Virulence Factors
PubMed: 32575670
DOI: 10.3390/toxins12060411 -
Toxins May 2020During infection, the foodborne bacterial pathogen dynamically influences the gene expression profile of host cells. Infection-induced transcriptional changes are a... (Review)
Review
During infection, the foodborne bacterial pathogen dynamically influences the gene expression profile of host cells. Infection-induced transcriptional changes are a typical feature of the host-response to bacteria and contribute to the activation of protective genes such as inflammatory cytokines. However, by using specialized virulence factors, bacterial pathogens can target signaling pathways, transcription factors, and epigenetic mechanisms to alter host gene expression, thereby reprogramming the response to infection. Therefore, the transcriptional profile that is established in the host is delicately balanced between antibacterial responses and pathogenesis, where any change in host gene expression might significantly influence the outcome of infection. In this review, we discuss the known transcriptional and epigenetic processes that are engaged during infection, the virulence factors that can remodel them, and the impact these processes have on the outcome of infection.
Topics: Animals; Cellular Reprogramming; Epigenesis, Genetic; Host-Pathogen Interactions; Humans; Inflammation Mediators; Listeria monocytogenes; Listeriosis; Signal Transduction; Transcription Factors; Transcription, Genetic; Virulence; Virulence Factors
PubMed: 32380645
DOI: 10.3390/toxins12050294 -
FEMS Microbiology Letters Sep 2021Listeria monocytogenes is the causative agent of the highly fatal foodborne disease listeriosis and can persist in food production environments. Recent research...
Listeria monocytogenes is the causative agent of the highly fatal foodborne disease listeriosis and can persist in food production environments. Recent research highlights the involvement of L. monocytogenes plasmids in different stress response mechanisms, which contribute to its survival in food production facilities. Ultraviolet (UV) light in the UVC spectrum (200-280 nm) is used in food production to control microbial contamination. Although plasmid-encoded UV resistance mechanisms have been described in other bacteria, no research indicates that L. monocytogenes plasmids contribute to the UV stress response. The plasmids of L. monocytogenes strains 6179, 4KSM and R479a are genetically distinct and were utilized to study the roles of plasmids in the UV response. Wild-type and plasmid-cured variant cells were grown to logarithmic or late-stationary phase, plated on agar plates and exposed to UVC for 60 or 90 s, and colony-forming units (CFUs) were determined. CFUs of 6179 and 4KSM, bearing pLM6179 and p4KSM, respectively, were significantly (P-value < 0.05) higher than those of the plasmid-cured strains in both logarithmic and stationary phases. No difference in survival was observed for the R479a strain. Our data show for the first time that certain L. monocytogenes plasmids contribute to the survival of UVC light stress.
Topics: Food Microbiology; Humans; Listeria monocytogenes; Listeriosis; Plasmids; Stress, Physiological; Ultraviolet Rays
PubMed: 34498664
DOI: 10.1093/femsle/fnab123 -
Molecular Microbiology Apr 2020CodY is a global transcriptional regulator that controls, directly or indirectly, the expression of dozens of genes and operons in Listeria monocytogenes. We used in...
CodY is a global transcriptional regulator that controls, directly or indirectly, the expression of dozens of genes and operons in Listeria monocytogenes. We used in vitro DNA affinity purification combined with massively parallel sequencing (IDAP-Seq) to identify genome-wide L. monocytogenes chromosomal DNA regions that CodY binds in vitro. The total number of CodY-binding regions exceeded 2,000, but they varied significantly in their strengths of binding at different CodY concentrations. The 388 strongest CodY-binding regions were chosen for further analysis. A strand-specific analysis of the data allowed pinpointing CodY-binding sites at close to single-nucleotide resolution. Gel shift and DNase I footprinting assays confirmed the presence and locations of several CodY-binding sites. Surprisingly, most of the sites were located within genes' coding regions. The binding site within the beginning of the coding sequence of the prfA gene, which encodes the master regulator of virulence genes, has been previously implicated in regulation of prfA, but this site was weaker in vitro than hundreds of other sites. The L. monocytogenes CodY protein was functionally similar to Bacillus subtilis CodY when expressed in B. subtilis cells. Based on the sequences of the CodY-binding sites, a model of CodY interaction with DNA is proposed.
Topics: Bacterial Proteins; Binding Sites; DNA, Bacterial; DNA-Binding Proteins; Gene Expression Regulation, Bacterial; Listeria monocytogenes; Protein Binding; Transcription Factors; Virulence Factors
PubMed: 31944451
DOI: 10.1111/mmi.14449 -
BMC Microbiology Jun 2019Ready-to-eat (RTE) vegetables have become increasingly popular along with the trend of moving towards a healthy lifestyle. However, RTE vegetables are at a higher risk...
BACKGROUND
Ready-to-eat (RTE) vegetables have become increasingly popular along with the trend of moving towards a healthy lifestyle. However, RTE vegetables are at a higher risk of containing pathogens, maybe owing to lack of rigorous sanitization procedures. To understand the prevalence and potential risk of Listeria monocytogenes in RTE vegetables, we investigated the contamination level and characteristics of L. monocytogenes isolated from fresh vegetables.
RESULTS
Twenty-three (5.49%) of the 419 vegetables samples were positive for L. monocytogenes. Phylogenetic group I.1 (1/2a-3a) and II.2 (1/2b-3b-7) strains were predominant in 30 isolates, which accounted for 33.3 and 50.0%, respectively. Multilocus sequence typing of the 30 isolates grouped them into nine sequence types (STs). The most common STs were ST87 (36.7%) and ST8 (26.7%). Virulence analysis showed that all 30 isolates harbored eight classical virulence genes, 10.0% isolates harbored the llsX gene (ST3 and ST1 strains), and 36.7% carried the ptsA gene and belonged to ST87. Approximately 83.3% isolates carried full-length inlA, whereas five isolates had premature stop codons in inlA, three of which belonged to ST9 and two to ST8. Antibiotic susceptibility showed the isolates were varyingly resistant to 13 antibiotics, 26.7% of the isolates were multi-drug resistant.
CONCLUSIONS
The fresh vegetables contain some potential hypervirulent L. monocytogenes (ST1 and ST87) in the Chinese markets. In addition, the high rate of L. monocytogenes isolates was multi-drug resistant. Fresh raw vegetables may be a possible transmission route for L. monocytogenes infection in consumers. Therefore, sanitization of raw fresh vegetables should be strengthened to ensure their microbiological safety when used as RTE vegetables.
Topics: Bacterial Proteins; Bacterial Typing Techniques; China; Codon, Terminator; Drug Resistance, Multiple, Bacterial; Food Microbiology; Listeria monocytogenes; Multilocus Sequence Typing; Phylogeny; Prevalence; Vegetables; Virulence Factors
PubMed: 31159734
DOI: 10.1186/s12866-019-1488-5 -
Frontiers in Immunology 2020is a Gram-positive foodborne bacterial pathogen capable of interacting and crossing the intestinal barrier, blood-brain barrier, and placental barrier to cause deadly... (Review)
Review
is a Gram-positive foodborne bacterial pathogen capable of interacting and crossing the intestinal barrier, blood-brain barrier, and placental barrier to cause deadly infection with high mortality. is an intracellular pathogen characterized by its ability to enter non-phagocytic cells. Expression of the cytolysin listeriolysin O has been shown to be the main virulence determinant and in mouse models. can also perform cell-to-cell spreading using actin-rich membrane protrusions to infect neighboring cells, which also constitutes an important strategy for infection. These events including entry into host cells, interaction between listeriolysin O and host plasma membrane, and bacterial cell-to-cell spreading have been demonstrated to implicate the cholesterol-rich lipid rafts or molecules in these microdomains in the host plasma membrane with tissue culture models. Here we review the contribution of lipid rafts on plasma membrane to infection.
Topics: Animals; Bacterial Toxins; Heat-Shock Proteins; Hemolysin Proteins; Host-Pathogen Interactions; Humans; Listeria monocytogenes; Listeriosis; Membrane Microdomains; Virulence
PubMed: 32849575
DOI: 10.3389/fimmu.2020.01666 -
Food Microbiology May 2020Dry dairy powder is a commonly used ingredient for ready-to-eat foods. It has been implicated in multiple foodborne outbreaks. Listeria monocytogenes can survive in...
Dry dairy powder is a commonly used ingredient for ready-to-eat foods. It has been implicated in multiple foodborne outbreaks. Listeria monocytogenes can survive in low-moisture conditions for a long duration. However, there is no information on Listeria survival in dry milk powder during storage and thermal treatments. The objectives of this study were to examine the stability of L. monocytogenes in non-fat dry milk (NFDM) during extended storage and further analyze thermal resistance of L. monocytogenes in NFDM under different water activities (a) and its thermal stability after 1-year storage. We observed approximately 1.75 and 2.93 log CFU/g reduction of L. monocytogenes in a 0.25 NFDM over 1-year storage at 4 and 22 °C, respectively. Thermal resistance of L. monocytogenes was inversely related to a, and the inactivation kinetic curves of L. monocytogenes in NFDM at target a showed a log-linear trend under all tested conditions. For a 0.25, 0.30, and 0.45 NFDM, the ranges of D-values, were 66.2-21.3, 33.5-9.4, and 14.6-4.3 min at 70, 75 and 80 °C, respectively. The z-values for L. monocytogenes in NFDM at a 0.25-0.45 were 14.6-16.0 C°. Furthermore, the thermal stability of L. monocytogenes in a 0.25 NFDM post 6-month or 12-month storage under refrigerated or ambient temperature did not deviate much from that in NFDM prior to the storage. Data indicated that a 60-min heat treatment at 80 °C resulted in ~ 5-log reduction of L. monocytogenes in NFDM of a 0.30. This provides a promising intervention strategy to enhance bactericidal efficacy of thermal treatment while maintaining the quality of milk powder.
Topics: Animals; Cattle; Colony Count, Microbial; Food Storage; Hot Temperature; Listeria monocytogenes; Milk; Powders; Temperature; Water
PubMed: 31948617
DOI: 10.1016/j.fm.2019.103376