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Scientific Reports Sep 2021The lack of bacteriophages capable of infecting the Listeria species, Listeria grayi, is academically intriguing and presents an obstacle to the development of...
The lack of bacteriophages capable of infecting the Listeria species, Listeria grayi, is academically intriguing and presents an obstacle to the development of bacteriophage-based technologies for Listeria. We describe the isolation and engineering of a novel L. grayi bacteriophage, LPJP1, isolated from farm silage. With a genome over 200,000 base pairs, LPJP1 is the first and only reported jumbo bacteriophage infecting the Listeria genus. Similar to other Gram-positive jumbo phages, LPJP1 appeared to contain modified base pairs, which complicated initial attempts to obtain genomic sequence using standard methods. Following successful sequencing with a modified approach, a recombinant of LPJP1 encoding the NanoLuc luciferase was engineered using homologous recombination. This luciferase reporter bacteriophage successfully detected 100 stationary phase colony forming units of both subspecies of L. grayi in four hours. A single log phase colony forming unit was also sufficient for positive detection in the same time period. The recombinant demonstrated complete specificity for this particular Listeria species and did not infect 150 non-L. grayi Listeria strains nor any other bacterial genus. LPJP1 is believed to be the first reported lytic bacteriophage of L. grayi as well as the only jumbo bacteriophage to be successfully engineered into a luciferase reporter.
Topics: Bacteriophages; Environmental Monitoring; Food Safety; Genetic Engineering; Listeria; Luciferases; Silage
PubMed: 34556683
DOI: 10.1038/s41598-021-98134-1 -
Applied Microbiology and Biotechnology Jun 2016The genus Listeria is currently comprised of 17 species, including 9 Listeria species newly described since 2009. Genomic and phenotypic data clearly define a distinct... (Review)
Review
The genus Listeria is currently comprised of 17 species, including 9 Listeria species newly described since 2009. Genomic and phenotypic data clearly define a distinct group of six species (Listeria sensu strictu) that share common phenotypic characteristics (e.g., ability to grow at low temperature, flagellar motility); this group includes the pathogen Listeria monocytogenes. The other 11 species (Listeria sensu lato) represent three distinct monophyletic groups, which may warrant recognition as separate genera. These three proposed genera do not contain pathogens, are non-motile (except for Listeria grayi), are able to reduce nitrate (except for Listeria floridensis), and are negative for the Voges-Proskauer test (except for L. grayi). Unlike all other Listeria species, species in the proposed new genus Mesolisteria are not able to grow below 7 °C. While most new Listeria species have only been identified in a few countries, the availability of molecular tools for rapid characterization of putative Listeria isolates will likely lead to future identification of isolates representing these new species from different sources. Identification of Listeria sensu lato isolates has not only allowed for a better understanding of the evolution of Listeria and virulence characteristics in Listeria but also has practical implications as detection of Listeria species is often used by the food industry as a marker to detect conditions that allow for presence, growth, and persistence of L. monocytogenes. This review will provide a comprehensive critical summary of our current understanding of the characteristics and distribution of the new Listeria species with a focus on Listeria sensu lato.
Topics: Biological Evolution; Genome, Bacterial; Listeria; Listeria monocytogenes; Phylogeny; Species Specificity; Virulence
PubMed: 27129530
DOI: 10.1007/s00253-016-7552-2 -
Veterinary Medicine International 2022A cross-sectional study was conducted to estimate the prevalence and associated risk factors of species and assess the antibiogram of () isolated from milk and milk...
A cross-sectional study was conducted to estimate the prevalence and associated risk factors of species and assess the antibiogram of () isolated from milk and milk products from Holeta, Ambo, and Bako towns, Ethiopia. A total of 482 samples (384 milk, 35 cottage cheeses, 30 bulk tank milk, and 33 curdle milk) were collected using a systematic random sampling method and isolation and identification of species were done using standard microbiological techniques. An antimicrobial susceptibility test for was performed using the Kirby-Bauer disk diffusion technique. Descriptive statistics were used to summarize the prevalence of while the Chi-square test and logistic regression were used to determine the association between the prevalence of and the risk factors and the magnitude of association, respectively. The overall isolation rate of species from milk and milk products was 7.67% (37/482; 95% confidence interval (CI): 5.46, 10.42). The highest prevalence of species (15.15%; 95% CI: 5.11-31.90) was detected in bulk tank milk and the lowest prevalence of species (6.67%; 95% CI: 0.82-22.07) and (0.00; 95% CI: 0.00-1.15) was found in curdled milk. The other species isolated were 0.62% (3/482; 95% CI: 0.13-1.81), 1.04% (5/482; 95% CI: 0.33-2.40), 1.24%, (6/482; 95% CI: 0.45-2.68), and 2.49% (12/482; 95% CI: 5.46-10.42). Univariable logistic regression showed that study town, herd size, farm size, number of lactating cows, and management system were the factors significantly associated with the isolation of species at farm level, while the intensive management system was the independent predictor at cow level in the multivariable model (adjusted odds ratio = 3.38, =0.046). isolates showed the highest resistance against oxacillin (100%), amoxicillin (90.91%), and vancomycine (81.82%). showed a very high multidrug resistance (MDR) [81.82%]. In conclusion, the current study showed the widespread type of species MDR isolates in cow raw milk and milk products from Ambo, Holeta, and Bako towns, Oromia Regional State, Ethiopia.
PubMed: 35465403
DOI: 10.1155/2022/5643478 -
Veterinary World Feb 2020This study was undertaken to isolate (.) species from raw meats sold in markets in Enugu State, Southeast Nigeria, and to determine the antibacterial resistance profile.
AIM
This study was undertaken to isolate (.) species from raw meats sold in markets in Enugu State, Southeast Nigeria, and to determine the antibacterial resistance profile.
MATERIALS AND METHODS
Twenty-five grams of beef (n=144), chicken meat (n=144), and pork (n=144) were collected randomly from supermarkets and general markets in Enugu State. Isolation of was done using half and full Fraser broths, and polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol agar. Identification of isolates was done using an analytical profile index kit specific for . Confirmation of the genus was done by a polymerase chain reaction. The resistance of the isolates was determined using the disk diffusion method.
RESULTS
was isolated from 39/144 (27.1%) chicken meat, 19/144 (13.2%) pork, and 66/144 (45.8%) beef samples cultured. was the predominant species in chicken meat (52.6%) and beef (81.8%) samples. , , and were also isolated from the beef and chicken meat samples. More than 65% of the isolates were resistant to penicillin, rifampicin, ciprofloxacin, sulfamethoxazole-trimethoprim, and cephalothin. All the isolates from beef and pork samples and 23 (92%) from chicken meat samples, were resistant to ≥3 classes of antibacterial agents. Mean multiple antibiotic resistance index (MARI) was 0.77 (range=0.42-1.00), 0.58 (range=0.25-0.83), and 0.79 (range=0.58-0.92) for the isolates from beef, chicken meat, and pork samples, respectively. All the isolates had MARI >0.2.
CONCLUSION
Multidrug-resistant strains contaminate raw beef, pork, and chicken meats marketed in Enugu State, Southeast Nigeria.
PubMed: 32255974
DOI: 10.14202/vetworld.2020.317-325 -
Infection and Drug Resistance 2021Listeriosis is one of the globally distributed foodborne diseases with the highest fatality rate. The objectives of this study were to isolate and identify species,...
PURPOSE
Listeriosis is one of the globally distributed foodborne diseases with the highest fatality rate. The objectives of this study were to isolate and identify species, assess factors for contamination of beef, and antibiogram of in Ambo and Holeta towns, Central Ethiopia.
MATERIALS AND METHODS
A total of 450 meat samples were collected from abattoirs (n=150), butchers (n=150), and restaurants (n=150) for isolation and identification of species. Logistic regression analysis was used to assess the association between the occurrence of species in meat and potential risk factors. The antimicrobial susceptibility test was done using the Kirby Bauer test.
RESULTS
The overall occurrence of species in Ambo and Holeta towns was 28.4% (128/450; 95% confidence interval [CI]: 24.3-32.9%). The isolation rate of was 4.4%, 2.2%, 1.8%, 3.8%, 6.2%, and 10.2%. The probability of contamination of meat in butchers and restaurants was higher in Holeta than Ambo [OR=3.4; 95%; p=0.001], in dry than wet season [OR=5.2; p=0.009], and where the hygiene of cutting boards was poor (OR=7.7; p=0.008). Of the 20 isolates, 80%, 70%, 60%, and 55% were resistant to oxacillin, amikacin, and nalidixic acid, chloramphenicol, and tetracycline, respectively. The isolates were 95%, 90%, and 85% susceptible to amoxicillin, vancomycin, and clindamycin, respectively. About 95% of isolates were multidrug-resistant. One isolate (5%) had developed resistance to 10 classes of antimicrobial drugs.
CONCLUSION
species are widespread and study towns, season, and hygiene of cutting boards are independent predictors of isolation of species. Multidrug resistance among was very high. Therefore, adequate cooking of meat, regular training of beef handlers, prudent use of drugs, and further molecular studies on species are important.
PubMed: 33907427
DOI: 10.2147/IDR.S304871 -
Parasites & Vectors Dec 2014Ixodes scapularis is the most common tick species in North America and a vector of important pathogens that cause diseases in humans and animals including Lyme disease,...
BACKGROUND
Ixodes scapularis is the most common tick species in North America and a vector of important pathogens that cause diseases in humans and animals including Lyme disease, anaplasmosis and babesiosis. Tick defensins have been identified as a new source of antimicrobial agents with putative medical applications due to their wide-ranging antimicrobial activities. Two multigene families of defensins were previously reported in I. scapularis. The objective of the present study was to characterise the potential antimicrobial activity of two defensins from I. scapularis with emphasis on human pathogenic bacterial strains and important phytopathogenic fungi.
METHODS
Scapularisin-3 and Scapularisin-6 mature peptides were chemically synthesised. In vitro antimicrobial assays were performed to test the activity of these two defensins against species of different bacterial genera including Gram-positive bacteria Staphylococcus aureus, Staphylococcus epidermidis, and Listeria spp. as well as Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa along with two plant-pathogenic fungi from the genus Fusarium. In addition, the tissue-specific expression patterns of Scapularisin-3 and Scapularisin-6 in I. scapularis midgut, salivary glands and embryo-derived cell lines were determined using PCR. Finally, tertiary structures of the two defensins were predicted and structural analyses were conducted.
RESULTS
Scapularisin-6 efficiently killed L. grayi, and both Scapularisin-3 and Scapularisin-6 caused strong inhibition (IC50 value: ~1 μM) of the germination of plant-pathogenic fungi Fusarium culmorum and Fusarium graminearum. Scapularisin-6 gene expression was observed in I. scapularis salivary glands and midgut. However, Scapularisin-3 gene expression was only detected in the salivary glands. Transcripts from the two defensins were not found in the I. scapularis tick cell lines ISE6 and ISE18.
CONCLUSION
Our results have two main implications. Firstly, the anti-Listeria and antifungal activities of Scapularisin-3 and Scapularisin-6 suggest that these peptides may be useful for (i) treatment of antibiotic-resistant L. grayi in humans and (ii) plant protection. Secondly, the antimicrobial properties of the two defensins described in this study may pave the way for further studies regarding pathogen invasion and innate immunity in I. scapularis.
Topics: Animals; Anti-Infective Agents; Defensins; Fusarium; Guinea Pigs; Humans; Ixodes; Listeria; Microbial Sensitivity Tests; Models, Molecular; Protein Conformation; Staphylococcus epidermidis
PubMed: 25443032
DOI: 10.1186/s13071-014-0554-y -
Journal of Food Protection Mar 2022Reference methods developed for detection of Listeria monocytogenes are commonly used for detection of Listeria at the genus level. Improved method performance data are...
Assessment of Reference Method Selective Broth and Plating Media with 19 Listeria Species Highlights the Importance of Including Diverse Species in Listeria Method Evaluations.
ABSTRACT
Reference methods developed for detection of Listeria monocytogenes are commonly used for detection of Listeria at the genus level. Improved method performance data are needed because this genus has expanded from 6 to 26 species and now includes several Listeria sensu lato species, which can have phenotypes distinct from those of Listeria sensu stricto. We evaluated growth of 19 Listeria species, including 12 recently described Listeria sensu lato species, using the media specified by (i) the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual, (ii) the U.S. Department of Agriculture (USDA) Microbiology Laboratory Guidebook, and (iii) the International Organization for Standardization (ISO). The FDA broth enrichment procedure allowed all species to grow to detectable levels (≥4 log CFU/mL), yielded the highest mean growth (7.58 log CFU/mL), and was the only procedure with which no Listeria sensu lato species yielded significantly higher growth than did a comparison Listeria sensu stricto species. With the USDA and ISO broth enrichment procedures, several Listeria sensu lato species yielded significantly higher growth than did either Listeria seeligeri or Listeria ivanovii, suggesting that these two Listeria sensu stricto species could be outgrown by Listeria sensu lato species. On selective and differential agar media, L. seeligeri, L. ivanovii, and Listeria grayi produced colonies with atypical morphology and/or growth of these species was inhibited (which may lead to incorrect classification of a sample as negative), whereas several newly described Listeria sensu lato species grew to high levels and produced colonies with typical morphology. Overall, our study results indicate that the ability to detect various Listeria species can be impacted by the specific broth and selective and differential agar used. Our data can help guide selection of appropriate media and detection methods for environmental Listeria monitoring programs and methods that are most likely to detect the targeted Listeria groups (e.g., Listeria sensu stricto, which appear to be the most appropriate index organisms for the pathogen L. monocytogenes).
Topics: Culture Media; Food Microbiology; Listeria; Listeria monocytogenes
PubMed: 34855940
DOI: 10.4315/JFP-21-293 -
MBio Feb 2024Since 2010, the genus has had the addition of 22 new species that more than tripled the number of species identified until 2010. Sixteen of these 22 new species are... (Review)
Review
Since 2010, the genus has had the addition of 22 new species that more than tripled the number of species identified until 2010. Sixteen of these 22 new species are distantly related to the type species, , and several of these present phenotypes that distinguish them from classical species (, , , , and ). These 22 newly described species also show that is more genetically diverse than previously estimated. While future studies and surveys are needed to clarify the distribution of these species, at least some of these species may not be widely spread, while other species may be frequently found spread to human-related settings (e.g., farms and processing facilities), and others may be adapted to specific environmental habitats. Here, we review the taxonomic, phylogenetic, and ecological characteristics of these new species identified since 2010 and re-iterate the suggestion of re-classification of some species into three new genera: , , and . We also provide a review of current detection issues and the relevance to food safety related to the identification of these new species. For example, several new non-pathogenic species could be misidentified as the pathogen , based on methods that do not target -specific virulence genes/factors, leading to unnecessary product recalls. Moreover, eight species in the proposed new genus are not good indicators of environmental conditions that could allow to grow since species are unable to grow at low temperatures.
Topics: Humans; Phylogeny; Listeria; Listeria monocytogenes; Virulence Factors; Food Safety
PubMed: 38126771
DOI: 10.1128/mbio.00938-23 -
Journal of Food Protection Jan 2020Hass avocados may become contaminated with and at the farm and the packing facility or later during transportation and at retail. In Mexico, avocados are frequently...
Hass avocados may become contaminated with and at the farm and the packing facility or later during transportation and at retail. In Mexico, avocados are frequently sold in bulk at retail markets, where they are stored at room temperature for several hours or days and exposed to potential sources of microorganisms. These conditions may favor the entry, adhesion, survival, and biofilm formation of and . The aim of this study was to determine the occurrence of and other species and the levels of indicator microorganisms on the surface of avocados sold at retail markets. A total of 450 samples ( var. Hass) were acquired from retail markets located in Guadalajara, Mexico. One group of 225 samples was evaluated for the presence of and for enumeration of aerobic plate counts, yeasts and molds, coliforms, and . The other 225 samples were processed for isolation of and other species. Microbial counts (log CFU per avocado) were 4.3 to 9.0 for aerobic plate counts, 3.3 to 7.1 for yeasts and molds, 3.3 to 8.2 for 3.3 to 8.4 for coliforms, and 3.3 to 6.2 for . Eight samples (3.5%) were positive for spp. and were detected in 31 (13.8%) and 18 (8.0%) of 225 samples, respectively. and were isolated from 7.6, 1.3, and 0.9% of samples. These results indicate that avocados may carry countable levels of microorganisms and could be a vehicle for transmission of and .
Topics: Colony Count, Microbial; Escherichia coli; Food Contamination; Food Microbiology; Fruit; Listeria; Listeria monocytogenes; Mexico; Persea; Salmonella
PubMed: 31851548
DOI: 10.4315/0362-028X.JFP-19-273 -
Prevalence and contamination levels of Listeria monocytogenes in smoked fish and pâté sold in Spain.Journal of Food Protection Dec 2001From March to November 2000, 170 samples of smoked fish and 182 samples of pâté for sale in retail outlets and supermarkets in the nine provinces of Castilla and León...
From March to November 2000, 170 samples of smoked fish and 182 samples of pâté for sale in retail outlets and supermarkets in the nine provinces of Castilla and León (Spain) were analyzed for the prevalence of Listeria monocytogenes and other Listeria spp. L. monocytogenes was isolated from 38 (22.3%) of the 170 samples of smoked fish analyzed. Twenty of these positive samples contained L. monocytogenes at >100 CFU/g. Other Listeria spp., such as Listeria innocua (26 isolates), Listeria grayi (9), Listeria welshimeri (3), Listeria seeligeri (3), and Listeria ivanovii (2), were also detected. L. monocytogenes was isolated from 5.4% of the 182 samples of pâté. Only 1 of the 10 positive samples harbored >100 L. monocytogenes CFU/g. Two other species of Listeria were observed in pâté: L. innocua (12 isolates) and L. grayi (2).
Topics: Animals; Colony Count, Microbial; Fishes; Food Contamination; Food Microbiology; Listeria; Listeria monocytogenes; Prevalence; Smoke; Spain
PubMed: 11770642
DOI: 10.4315/0362-028x-64.12.2075