scholarly journals Whole Genome Analysis of Three Multi-Drug Resistant Listeria innocua and Genomic Insights Into Their Relatedness With Resistant Listeria monocytogenes

2021 ◽  
Vol 12 ◽  
Author(s):  
Menghan Li ◽  
Shaofei Yan ◽  
Séamus Fanning ◽  
Fengqin Li ◽  
Jin Xu
Keyword(s):  
Listeria Monocytogenes ◽  
Virulence Gene ◽  
Listeria Innocua ◽  
Ecological Niches ◽  
Drug Resistant ◽  
M Gene ◽  
Public Health Importance ◽  
Sequence Alignments ◽  
Whole Genome Analysis ◽  
Virulence Markers

Listeria innocua are Gram-positive rod-shaped bacteria, which are not generally infectious as opposed to Listeria monocytogenes. However, the comparatively high genomic similarity between both along with on occasion, their coexistence in similar ecological niches may present the opportunity for resistance or virulence gene transfer. In this study, three multi-drug resistant L. innocua originally cultured from food were put forward for long-read genome sequencing. Chromosome and plasmid genomes were assembled and annotated. Analysis demonstrated that the resistant phenotypes correlated well with genotypes. Three plasmids pLI42, pLI203, and pLI47-1 were identified which harbor resistance islands. Sequence alignments suggested that plasmids pLI42 and pLI203 were highly similar to a previously sequenced L. monocytogenes plasmid pLR1. Similarly, another three types of resistance gene islands were observed on chromosome, including tet(M) gene islands (transposon Tn916 orthologs), dfrG gene islands and optrA-erm(A) gene islands. All three L. innocua isolates possessed listeria pathogenicity island-4 (LIPI-4) which is linked to cases of mengitis. Further genome environment and phylogenic analysis of regions flanking LIPI-4 of L. innocua and L. monocytogenes showed that these may have common origins and with the potential to transmit from the former. Our findings raise the possible need to include both L. monocytogenes and L. innocua in food surveillance programs so as to further understand of the origins of antimicrobial resistance and virulence markers of public health importance in L. monocytogenes.

scholarly journals Genetic and phenotypic characterization of Listeria monocytogenes lineage III

Microbiology ◽  
2006 ◽  
Vol 152 (3) ◽  
pp. 685-693 ◽  
Author(s):  
Angela Roberts ◽  
Kendra Nightingale ◽  
Greg Jeffers ◽  
Esther Fortes ◽  
Jose Marcelino Kongo ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Phylogenetic Analyses ◽  
Plaque Assay ◽  
Virulence Gene ◽  
Phenotypic Characterization ◽  
Ecological Niches ◽  
Phenotypic Characteristics ◽  
Putative Virulence Gene ◽  
Clinical Cases

Listeria monocytogenes has been previously grouped into three evolutionary groups, termed lineages I, II and III. While lineages I and II are commonly isolated from various sources, lineage III isolates are rare and have several atypical and unique phenotypic characteristics. Relative to their prevalence in other sources, lineage III strains are overrepresented among isolates from food-production animals, and underrepresented among isolates from human clinical cases and foods. This work describes an extensive genotypic and phenotypic characterization of 46 lineage III isolates. Phylogenetic analyses of partial sigB and actA sequences showed that lineage III represents three distinct subgroups, which were termed IIIA, IIIB and IIIC. Each of these lineage III subgroups is characterized by differentiating genotypic and phenotypic characteristics. Unlike typical L. monocytogenes, all subgroup IIIB and IIIC isolates lack the ability to ferment rhamnose. While all IIIC and most IIIB isolates carry the putative virulence gene lmaA, the majority of subgroup IIIA isolates lack this gene. All three lineage III subgroups contain isolates from human clinical cases as well as isolates that are cytopathogenic in a cell culture plaque assay, indicating that lineage III isolates have the potential to cause human disease. The identification of specific genotypic and phenotypic characteristics among the three lineage III subgroups suggests that these subgroups may occupy different ecological niches and, therefore, may be transmitted by different pathways.

Phenotypic and Molecular Characteristics of Pseudomonas Aeruginosa Isolated from Burn Unit

2021 ◽  
Vol 30 (1) ◽  
pp. 19-28
Author(s):  
Yasser M. Ismail ◽  
Sahar M. Fayed ◽  
Fatma M. Elesawy ◽  
Nora Z Abd El-Halim ◽  
Ola S. El-Shimi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Antimicrobial Susceptibility ◽  
Virulence Gene ◽  
Molecular Characteristics ◽  
Drug Resistant ◽  
Burn Wound ◽  
Burn Wounds ◽  
Related Data ◽  
Genes Encoding

Background: The biggest concern for a burn team is a nosocomial infection in burn patients, which is a significant health issue. Pseudomonas aeruginosa is an extremely troublesome drug-resistant bacterium in the world today. We are now faced with rising P. aeruginosa pan-drug-resistant clones in hospital settings. Objectives: To evaluate the distribution of different virulence factors generated by P. aeruginosa isolated from burn wound infections, together with its antimicrobial susceptibility. Methodology: The isolates reported as P. aeruginosa were further tested for the presence of various phenotypic and genotypic virulence factors including (Biofilm formation, lipase, protease, gelatinase, DNase, bile esculin hydrolysis & hemolysin). Also, genes encoding (nan 1 and Exo A) were investigated by PCR using specific primers. All the isolates were tested for their antimicrobial susceptibility patterns. Results: The study reported that toxins and enzymes were expressed by the tested strains in varying proportions; (92.0%) were producing β-hemolysin, lipase (86%), and protease (86%). The formation of biofilm was observed in 84%. Exo A (70%) was the main virulence gene found in the tested strains. Nan 1 gene was identified in 30% of the samples. 82% of MDRPA isolates were found. There is indeed a relationship between biofilm production and drug resistance, as well as the presence of virulence genes (nan 1 and Exo A) were associated with certain patients and burn wounds characteristics as burn size, burn wound depth, length of hospital stays, and socioeconomic status. Conclusions: Correlation of Pseudomonas aeruginosa virulence profiles with burn wounds and patient-related data can be useful in establishing of an appropriate preventive protocol for hospitalized patients with P. aeruginosa burn serious infections. The targeting of these bacterial virulence arsenals is also a promising approach to developing alternative drugs, which act by attenuating the aggressiveness of the pathogen and reducing its potential to cause vigorous infection.

scholarly journals Thermal inactivation and growth potential of Listeria monocytogenes in smoked tench

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Raffaella Branciari ◽  
Andrea Valiani ◽  
Raffaella Franceschini ◽  
David Ranucci ◽  
Alessia Lupattelli ◽  
...  
Keyword(s):  
Experimental Study ◽  
Listeria Monocytogenes ◽  
Thermal Inactivation ◽  
Challenge Test ◽  
Listeria Innocua ◽  
Growth Potential ◽  
Post Processing ◽  
Colony Forming Unit ◽  
Post Process ◽  
Hygiene Measures

An experimental study for the evaluation of <em>Listeria monocytogenes</em> inactivation during a hot smoking process in tench was performed using <em>Listeria innocua</em> strains. Furthermore, the survival of <em>L. monocytogenes</em> in smoked tench was determined after post-processing in contaminated samples, evaluating the growth potential during storage. <em>L. innocua</em> was not detected after the smoking process. In the challenge test, the growth potential of <em>L. monocytogenes</em> was 5.68 log colony forming unit g<sup>−1</sup>. The results showed that hot smoking at an inner temperature around 72°C is able to eliminate the microorganism. Nevertheless, the product is able to support the growth of the pathogen if post-process contamination occurs, as the food is suitable for <em>Listeria</em> multiplication. Product recontamination should be prevented by means of appropriate application of hygiene measures.

scholarly journals Klebsiella virus UPM2146 lyses multiple drug-resistant Klebsiella pneumoniae in vitro and in vivo

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245354
Author(s):  
Omar Assafiri ◽  
Adelene Ai-Lian Song ◽  
Geok Hun Tan ◽  
Irwan Hanish ◽  
Amalia Mohd Hashim ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Multiple Drug ◽  
Drug Resistant ◽  
Zebrafish Model ◽  
Whole Genome Analysis ◽  
Narrow Host Range ◽  
Opportunistic Bacteria ◽  
Multiple Drug Resistant

Klebsiella pneumoniae are opportunistic bacteria found in the gut. In recent years they have been associated with nosocomial infections. The increased incidence of multiple drug-resistant K. pneumoniae makes it necessary to find new alternatives to treat the disease. In this study, phage UPM2146 was isolated from a polluted lake which can lyse its host K. pneumoniae ATCC BAA-2146. Observation from TEM shows that UPM2146 belongs to Caudoviriales (Order) based on morphological appearance. Whole genome analysis of UPM2146 showed that its genome comprises 160,795 bp encoding for 214 putative open reading frames (ORFs). Phylogenetic analysis revealed that the phage belongs to Ackermannviridae (Family) under the Caudoviriales. UPM2146 produces clear plaques with high titers of 1010 PFU/ml. The phage has an adsorption period of 4 min, latent period of 20 min, rise period of 5 min, and releases approximately 20 PFU/ bacteria at Multiplicity of Infection (MOI) of 0.001. UPM2146 has a narrow host-range and can lyse 5 out of 22 K. pneumoniae isolates (22.72%) based on spot test and efficiency of plating (EOP). The zebrafish larvae model was used to test the efficacy of UPM2146 in lysing its host. Based on colony forming unit counts, UPM2146 was able to completely lyse its host at 10 hours onwards. Moreover, we show that the phage is safe to be used in the treatment against K. pneumoniae infections in the zebrafish model.

scholarly journals Antibacterial activity of plant extracts against Listeria monocytogenes isolated from ready-to-eat salads

2020 ◽  
Vol 13 (1) ◽  
pp. 131-143
Author(s):  
É. György ◽  
É. Laslo ◽  
E. Csató
Keyword(s):  
Listeria Monocytogenes ◽  
Essential Oils ◽  
Antibacterial Effect ◽  
Storage Conditions ◽  
Inhibitory Effect ◽  
Listeria Innocua ◽  
Foodborne Diseases ◽  
Bacterial Strains ◽  
Antibacterial Effects ◽  
Growth Environment

Abstract Ready-to-eat salads are becoming more and more popular. However, due to their ingredients, they represent a suitable growth environment for different microbes. In the prevention of foodborne diseases, hygienic food preparation and appropriate storage conditions are very important. During this study, ten different ready-to-eat salads were analysed for the presence of Listeria monocytogenes. Five different selective agar mediums were used for the enumeration and isolation of Listeria monocytogenes. The isolated bacterial strains were subjected to morphological and biochemical confirmation tests. The antibacterial effects of five different freshly squeezed vegetable juices (carrots, celery, beets, horseradish, and onions) and of five essential oils (dill, thyme, oregano, lemongrass, and sage) were determined against Listeria monocytogenes, Listeria innocua, and L. monocytogenes strains isolated from ready-to-eat salads. Based on the results obtained from fresh vegetable juices, carrot juice exerted the highest antibacterial effect, while the others showed no or slight inhibitory effect (horseradish, beets, onions) against Listeria species. Among the essential oils, thyme, lemongrass, and oregano showed the strongest antibacterial effect against the studied Listeria species.

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