Occurrence Of Listeria Species Research Articles

Epidemiology and antibiogram of listeria species from retail raw frozen atlantic mackerel fish (Scomber scombrus) in Nigeria

This study was undertaken to determine the epidemiology and antibiogram of Listeria species isolated from raw frozen Atlantic Mackerel (Scomber Scombrus) fish sold in Enugu State Southeastern Nigeria. Twentyfive grams each of raw fish gut and skin were collected from 800 raw fish sold in 8 major markets randomly selected from the study area. Isolation of Listeria was done using half and full fraser broths, and polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol (PALCAM) agar. Confirmation of the genus Listeria was done by a polymerase chain reaction. Identification of species was done using an analytic profile index (API) kit specific for Listeria. The antibiotic resistance of the isolates was determined using disc diffusion method. Out of the 800 fish samples, 38 (4.75%) were positive for Listeria species. Enugu North (6.50%) had significantly (P<0.05) higher prevalence than Enugu East (3.0%). Five Listeria species were identified. Listeria innocua (71.1%) predominated, followed by Listeria welshimeri (10.5%), Listeria ivanovii (7.9%), Listeria grayi (5.3%) and Listeria monocytogenes (5.3%). All the isolates were susceptible to the tested antibacterial agents. The occurrence of Listeria species in raw frozen Atlantic mackerel fish, poses a threat, when consumed raw or lightly cooked, to people especially the immunocomprormised persons whose population is increasing as a result of improvement in medical technology. Also, the possibility of cross contamination in the kitchen or food service establishments is also a concern. Since all the Listeria species got in this study showed 100% susceptibility to all the antimicrobials tested, therefore, there is no fear of acquiring and transferring antibiotic resistance genes from raw frozen Atlantic mackerel fish to the general human population.

Listeria Species Occurrence and Associated Factors and Antibiogram of Listeria monocytogenes in Beef at Abattoirs, Butchers, and Restaurants in Ambo and Holeta in Ethiopia.

PurposeListeriosis is one of the globally distributed foodborne diseases with the highest fatality rate. The objectives of this study were to isolate and identify Listeria species, assess factors for contamination of beef, and antibiogram of Listeria monocytogenes in Ambo and Holeta towns, Central Ethiopia.Materials and MethodsA total of 450 meat samples were collected from abattoirs (n=150), butchers (n=150), and restaurants (n=150) for isolation and identification of Listeria species. Logistic regression analysis was used to assess the association between the occurrence of Listeria species in meat and potential risk factors. The antimicrobial susceptibility test was done using the Kirby Bauer test.ResultsThe overall occurrence of Listeria species in Ambo and Holeta towns was 28.4% (128/450; 95% confidence interval [CI]: 24.3–32.9%). The isolation rate of Listeria monocytogenes was 4.4%, Listeria ivanovii 2.2%, Listeria seeligeri 1.8%, Listeria welshimeri 3.8%, Listeria innocua 6.2%, and Listeria grayi 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 Listeria monocytogenes isolates, 80%, 70%, 60%, and 55% were resistant to oxacillin, amikacin, and nalidixic acid, chloramphenicol, and tetracycline, respectively. The Listeria monocytogenes isolates were 95%, 90%, and 85% susceptible to amoxicillin, vancomycin, and clindamycin, respectively. About 95% of Listeria monocytogenes isolates were multidrug-resistant. One isolate (5%) had developed resistance to 10 classes of antimicrobial drugs.ConclusionListeria species are widespread and study towns, season, and hygiene of cutting boards are independent predictors of isolation of Listeria species. Multidrug resistance among Listeria monocytogenes was very high. Therefore, adequate cooking of meat, regular training of beef handlers, prudent use of drugs, and further molecular studies on Listeria species are important.

Occurrence of Multi-Drug Resistant <i>Listeria species</i> in Faecal Samples of Poultry Chickens in Rural Farms in Lagos State, Nigeria

Background: Listeriosis is a common zoonotic disease caused by a foodborne pathogen, Listeria monocytogenes. Poultry meat and products have been established as vehicles of transmission of pathogenic Listeria strains to humans. This study evaluates the occurrence of Listeria species in faeces of poultry chicken in Lagos. Methods: One hundred and fourteen pooled fresh faecal samples from cage-reared broiler chickens were collected from 12 farms in three rural areas in Lagos State from May to August 2019. All samples were analysed for Listeria species detection according to ISO11290-1 standard and confirmed using PCR assay. Susceptibility testing was performed using the Kirby-Bauer disc diffusion technique. Results: Twenty-eight (24.6%) Listeria species were detected from 114 faecal samples. The isolated Listeria species were L. monocytogenes 8 (7.0%), L. ivanovii 9 (7.9%), L. grayi 7 (6.1%) and L. innocua 4 (3.5%). There was no significant difference in the frequency of occurrence of Listeria species across the different locations (X2 = 4.98, p = 0.08). The listeria species were susceptible to Augmentin (96.4%), vancomycin (85.7%) and co-trimoxazole (82.1%), but resistant to ceftazidime (100%), tetracycline (75.0%) and ciprofloxacin (71.4%). Conclusion: This study reveals high occurrence of multi-drug resistant Listeria species in faecal samples of poultry chickens in Lagos state which may be an important vector in the contamination of the environment and transmission of antibiotic resistant Listeria species to consumers.

Listeria valentina sp. nov., isolated from a water trough and the faeces of healthy sheep.

In the context of a study on the occurrence of Listeria species in an animal farm environment in Valencia, Spain, six Listeria-like isolates could not be assigned to any known species. Phylogenetic analysis based on the 16S rRNA gene and on 231 Listeria core genes grouped these isolates in a monophyletic clade within the genus Listeria, with highest similarity to Listeria thailandensis. Whole-genome sequence analyses based on in silico DNA-DNA hybridization, the average nucleotide blast and the pairwise amino acid identities against all currently known Listeria species confirmed that these isolates constituted a new taxon within the genus Listeria. Phenotypically, these isolates differed from other Listeria species mainly by the production of acid from inositol, the absence of acidification in presence of methyl α-d-glucoside, and the absence of α-mannosidase and nitrate reductase activities. The name Listeria valentina sp. nov. is proposed for this novel species, and the type strain is CLIP 2019/00642T (=CIP 111799T=DSM 110544T).

Zoonotic and Molecular Aspects of Listeria Species Isolated From Some Farm Animals at Dakahlia Province in Egypt.

This study was performed in Dakahlia province, Egypt to investigate zoonotic and molecular aspects of Listeria species recovered from some farm animals and human. For this purpose, a total of 272 samples were collected from animals (146), milk (60) and man (66). Of which 146 fecal samples were collected from cattle (95), buffaloes (25), sheep (16) and goats (10). Meantime, 60 milk samples were taken from cattle (27), buffaloes (3) and sheep (30). Regarding human, 66 samples were included 54 stool samples from 30 adult, 9 previously aborted women and 15 preterm. Moreover, 12 vaginal swabs were collected from aborted women from patients admitted to Mansoura University hospitals and some private clinical laboratories. The results revealed that the occurrence of Listeria species was 17.1% in animal feces, 16.6% in milk samples. While, in human samples, it was 15.1%. Sheep feces showed higher occurrence (43.7%), buffalo’s milk was highest contamination rate (33.3%). The frequency distribution of Listeria species in stool of women, preterm, adults and vaginal swabs were 11.1%, 6.6%, 20.0% and 16.6%, respectively. Different Listeria species have been identified from animals, milk and humans, L. monocytogenes was the most identified strains (44.4%). Multiplex polymerase chain reaction (m. PCR) was used to detect the virulence genes (iap, hylA and actA) of 12 biochemically identified L. monocytogenes strains recovered from different sources using specific primers. The molecular characterization proved that m. PCR successfully amplified iap, hylA and actA virulence genes at specific base pair 131, 456 and 839 respectively. In conclusion, Listeria species were detected in the examined farm animals, its milk and humans, reflecting the zoonotic impact of such animals and its milk, moreover, same genotypes prevalent in farm animals, milk and humans suggesting that genotypes are transmissible between farm animals and man in the examined area, Egypt.

Comparison of Conventional Culture Method and Fluorescent In Situ Hybridization Technique for Detection of Listeria spp. in Ground Beef, Turkey, and Chicken Breast Fillets in İzmir, Turkey

The occurrence of Listeria species in refrigerated fresh chicken breast fillet, turkey breast fillet, and ground beef was evaluated, comparing the conventional culture method and fluorescent in situ hybridization (FISH). FISH uses hybridization of a nucleic acid sequence target of a microorganism with a specific DNA probe labeled with a fluorochrome and imaging by a fluorescence microscope. First, Listeria was inoculated in chicken breast fillet, turkey breast fillet, or ground beef, and the applicability of the FISH method was evaluated. Second, Listeria was detected in fresh chicken breast fillet, turkey breast fillet, and ground beef by culture and FISH methods. Listeria was isolated from 27 (37.4%) of 216 samples by the standard culture method, whereas FISH detected 25 (24.7%) preenriched samples. Of these isolates, 17 (63%) were L. innocua, 6 (22%) L. welshimeri, and 4 (14.8%) L. seeligeri. Overall, the prevalences of Listeria spp. found with the conventional culture method in chicken breast fillet, turkey breast fillet, and ground beef were 9.7, 6.9, and 20.8%, whereas with the FISH technique these values were 11.1, 6.9, and 16.7%, respectively. The molecular FISH technique appears to be a cheap, sensitive, and time-efficient procedure that could be used for routine detection of Listeria spp. in meat. This study showed that retail raw meats are potentially contaminated with Listeria spp. and are, thus, vehicles for transmitting diseases caused by foodborne pathogens, underlining the need for increased precautions, such as implementation of hazard analysis and critical control points and consumer food safety education.

Prevalence of Listeria Species in Environment and Milk Samples

The previous notion that infection by pathogenic Listeria (listeriosis) is not an important health problem in India starts to be revised now, mainly due to changing habits of the production, distribution and storage of food, favoring the multiplication and spread of cold–tolerant bacteria like Listeria. Despite this altering scenario, data on the prevalence of Listeria on the Indian subcontinent are still rather sporadic. We investigated the occurrence of Listeria species in environmental and raw milk samples from Mysore city (moderately hot, semi–arid climate). Environmental samples included cow dung from cowshed, grazing pasture and soil samples from vegetable–cultivation land. Cold enrichment was used to recover Listeria species from raw cow milk (from individual animals) (n=130), cow dung (collected from individual animals) (n=130) and soil (n=100) samples. 10 g sample in case of cowdung and soil and 10mL in case of milk were transferred to 90 mL BHI broth and incubated at 4oC for two weeks. Aliquots from the enriched broth were streaked on Oxford and PALCAM plates, at weekly intervals. Listeria isolates were subjected to phenotypic and genotypic characterization. Phenotypic characterization included standard biochemical tests such as catalase test, motility at 25 °C and 37 °C, acid production from the canonical panel of carbohydrates, nitrate reduction, esculin hydrolysis, methyl red and Voges Proskauer reaction. Genus– and species–specific primers were used for PCR differentiation of the isolates. L. ivanovii was isolated from 1% of the soil samples, L. seeligeri from 0.76% of the cowdung samples and L. innocua from 0.76% of the raw milk samples tested. Strategies to reduce the incidence of Listeria in environment and milk samples should be implemented.

Occurrence of Listeria species in meat, chicken products and human stools in Assiut city, Egypt with PCR use for rapid identification of Listeria monocytogenes

The present research was conducted to check the presence of Listeria spp. in some meat and chicken products purchased from retail supermarkets in Assiut (Egypt). A total of 100 samples including 25 samples each of minced frozen beef, luncheon, frozen chicken legs and frozen chicken breast fillets were collected over a 7-month period between January and July 2009 and analyzed for the presence of Listeria spp. In addition, 28 stool cultures examined for Listeria spp. from hospitalized children resident in Assiut Pediatric University Hospital with diarrhea or fever. Out of the total 100 meat samples examined, Listeria spp. were detected in 8 (32%) of minced frozen beef, 8 (32%) of luncheon, 13 (52%) of frozen chicken leg and 14 (56%) of frozen chicken fillet samples analyzed, respectively. Regarding the examined 28 stool cultures from hospitalized children with underlying disease in Assiut Univ. hospital, 2 (7.14%) were found positive for Listeria spp. For identification of L. monocytogenes using polymerase chain reaction (PCR), two primers were selected to detect 217-pb fragment ofthe prfA (transcriptional activator of the virulence factor) gene for L. monocytogenes. 13 selected Listeria isolates displayed beta-haemolysis on sheep blood agar and positive CAMP test were further identified using PCR. PCR results showed that L. monocytogenes were confirmed in one of minced imported frozen meat examined, two of luncheon samples and two of frozen chicken legs with the total incidence of 5 isolates (5%) from the total 100 examined food samples. This suggests the presence of a significant public health hazard linked to the consumption of these meat and chicken products sold in Assiut city contaminated with L. monocytogenes. The public health significance of these pathogens as well as recommended sanitary measures was discussed.

Occurrence and persistence of Listeria spp. in the environment of ewe and cow's milk cheese dairies in Portugal unveiled by an integrated analysis of identification, typing and spatial–temporal mapping along production cycle

Eight dairies, located in two distant geographic regions of Portugal, were screened along the production cycle in order to evaluate the presence and distribution of Listeria spp. in their environment. Three dairies in each region were positive for the presence of listeriae and 213 isolates were obtained. Based on an integrated analysis of RAPD fingerprints with three primers, molecular identification and genomic typing of isolates was performed followed by spatial and temporal mapping on dairy plants. The occurrence of Listeria species by region was noticeable different. Listeria monocytogenes prevailed in South Portugal dairies and L. innocua presented the highest occurrence in Azores, whereas L. seeligeri and L. ivanovii were detected in distinct regions. Dairies were at risk of contamination, from more than one source, whatever the stage in the production cycle and the surface materials used. For the three prevalent species, most of the genomic types were dairy and sampling time specific. Nonetheless, more than one type could be found in each dairy at a particular site and, in a few cases, even for different species. Some dairies also shared types, mainly for L. innocua and usually at the same stage of the production cycle. For L. monocytogenes, PCR serotyping was applied and 52% of genomic types were serotype 4b. An equal frequency of genomic types (24%) was found for serotypes 1/2b or 3b and 1/2a or 3a. The global pattern of types within a dairy is not constant, suggesting cycles of elimination and recontamination along the production cycle.

The occurrence of Listeria species and antibodies against listeriolysin-O in naturally infected goats

The occurrence of Listeria spp. in bacteriological samples, and antibodies against listeriolysin-O (ALLO) in sera of those aborted, mastitic and apparently healthy goats were studied. Isolation of the organism was attempted from the samples by selective enrichment in University of Vermont Medium and plating onto Dominguez–Rodriguez isolation agar. Pathogenicity of the isolates was tested by Christie, Atkins, Munch Petersen test, chick embryo inoculation and mice inoculation test. Listeria ivanovii was isolated from 7.5, 5.56 and 14.52% goats of those aborted, mastitic and apparently healthy, respectively. Out of the 120 samples each of feacal, nasal and vaginal swabs 5, 1.67 and 2.5% were positive for L. ivanovii. L. ivanovii was also isolated from 0.83% each of 120 milk and blood samples. L. seeligeri was isolated from 1.67% feacal samples from apparently healthy goats. A total of 120 serum samples were tested by listeriolysin-O (LLO) based indirect ELISA of which 19.16% turned out to be seropositive. The percentage of seropositivity was higher in goats those aborted.

Occurrence of Listeria species in raw milk in farms on the outskirts of Mexico city

Listerosis may be transmitted by direct contact with infected animals or by consumption of contaminated vegetables or meat and milk products. In Mexico, raw milk is widely consumed and the incidence of milkborne disease is unknown. A total of 1300 raw milk samples were obtained from 20 l bulk tanks at four different dairy farms in southeast of Mexico City from June 1998 to June 1999. The samples were enriched for 48 h at 30°C and plated onto McBride's Modified Agar (MMA). Suspect colonies were biochemically tested to confirm identity. Overall, 23% of all raw milk samples examined tested positive forListeria species; 13% were positive for L. monocytogenes (45·6% were serotype-4b and 54·4% were serotype 1); 6% for L. ivanovii; 4% for L. seeligeri and 1% forL. innocua. L. monocytogenes contamination was more frequent during the spring and summer months as isolation rates were 12·2% from June to October 1998 and 17% from March to June 1999. Serotype-4b isolates were not pathogenic for the mouse, while for serotype-1, strains DL50ranged from 1·8×106to 4×107CFU ml−1. Additional studies are needed to assess the public health impact of contaminated milk in Mexico.

Occurrence of Listeria species in retail poultry meat and comparison of a cultural/immunoassay for their detection

The prevalence of Listeria spp. on the skin of a hundred fresh chicken carcasses purchased from 20 retail stores in León was investigated using the routine test procedure recommended by the United States Department of Agriculture (USDA). PALCAM and Modified Oxford agar (MOX) were used for isolation. Listeria spp., Listeria monocytogenes, L. innocua, L. welshimeri, L. grayi and L. ivanovii were present in 95%, 32%, 66%, 7%, 4% and 2% of the samples, respectively. Next, an immunoassay test ( Listeria Rapid Test; Oxoid, Unipath) and the routine test procedure (USDA) were compared for their ability to detect Listeria spp. on 40 chicken carcasses. When we used MOX for the isolations, the sensitivity of the immunoassay test was 100% and the specificity 85.7%. When we used PALCAM medium the sensitivity and specificity of the test was 94.29% and 80%, respectively.

Occurrence of Listeria Species in Broilers Pre- and Post-Chilling in Chlorinated Water at Two Slaughterhouses

Altogether 323 pooled samples of neck skins from 1615 broilers from 2 processing plants (A and B) were examined for the presence of Listeria species. The broilers were sampled pre-chilling-after leaving the final rinser but before entering the chiller with chlorinated water-and post-chilling-immediately upon leaving the chiller. Free available chlorine in the chilling water varied from 2 to 15 ppm in plant A and was about 10 ppm in plant B. Listeria monocytogenes was only isolated from broilers in plant A sampled post-chilling (58% of 62 samples). L. innocua was isolated from 19% and 39% of broilers sampled pre-chilling in plants A and B, respectively. Post-chilling, L. innocua was isolated from 3% and 6% of samples from plants A and B, respectively.

Occurrence of Listeria Species in an Abattoir for Cattle and Pigs in Bosnia and Hercegovina

Altogether 496 samples of meat, lymph nodes, process water and swabs from different places in the abattoir were examined for the presence of Listeria spp. L. monocytogenes was isolated from 31 (6%) and other Listeria spp. from 65 (13%) samples L. monocytogenes was isolated from 2 of 10 beef meat samples, 4 of 50 pig meat samples and 1 of 21 lymph nodes of pigs. No Listeria bacteria were isolated from lymph nodes of cattle. The highest percentage of Listeria was recovered from the unclean sections (cattle 22% and pigs 27%) and the highest frequency was observed during the winter months.

Occurrence of Listeria species in raw milk and dairy products produced in Northern Ireland.

The overall incidence of Listeria spp. in raw milk samples surveyed was found to be 25.0% (Listeria monocytogenes 15.3%), with the incidence in samples from processing centres 54.0% (L. monocytogenes 33.3%); this was higher than that in samples from dairy farms (Listeria spp. 8.8%; L. monocytogenes 5.3%). The FDA enrichment procedure was much more productive than cold enrichment and Oxford agar was superior to modified McBride agar for isolation of Listeria. Listeria monocytogenes was never isolated by direct plating of raw milk samples on Oxford agar at a detection level of 1.0 cfu/ml. Listeria spp. were isolated from 1 of 95 pasteurized milk samples (L. monocytogenes) and 1 of 33 soft cheese samples (L. seeligeri). Restriction fragment length polymorphism was more useful than sero- or phage-typing for typing of L. monocytogenes strains, and results suggest that specific L. monocytogenes strains may persist in both farm and processing environments.

Occurrence of Listeria Species in Fresh Seafood

In order to clarify the status of contamination with Listeria spp. in commercial fresh seafood, a total of 683 samples were collected from wholesale and retail shops in the Tokyo metropolitan area and examined. Listeria spp. were detected in 68 (10.0%) of the 683 samples, and the detection rate tended to be higher in samples with a larger standard plate count. In most instances the Listeria species count was less than 10/g. The most frequently found Listeria species was L. innocua, from 51 samples (7.5%). L. monocytogenes was isolated from 12 samples (1.8%). The serotype of L. monocytogenes which was most frequently found was 4b, followed by 1/2a, 1/2b and 3b.

The occurrence of Listeria species in milk and dairy products: a national survey in England and Wales

A total of 4172 samples of milk, cheese and other dairy products were examined over a 1-year period for the presence of Listeria species. Strains of Listeria were found most frequently in soft, ripened cows milk cheese; 63 out of 769 (8.2%) samples contained Listeria monocytogenes, 25 samples contained species other than L. monocytogenes, and 18 samples contained both L. monocytogenes and other Listeria spp. Eleven samples of pasteurized cows milk (1.1%) from four dairies contained L. monocytogenes, and other Listeria spp. were isolated from a further five samples. Goats and ewes milk and their products, yoghourt, cream and ice cream also occasionally contained Listeria spp. Levels of Listeria were usually low, but 20 samples of cheese contained more than 1000 cfu/g. Most strains of L. monocytogenes belonged to serotype 1 2 (58%) or serotype 4b (33%).

Occurrence of Listeria Species in Food and Environmental Samples in Alberta

A total of 598 samples of food products and environmental swabs were analysed for Listeriaorganisms. Four percent of farm bulk raw milk samples contained Listeriaspp. and 1.6% yielded L. monocytogenes. The incidence of L. monocytogenes was much higher (26.6%) in raw milk from dairy plant silo tanks. All 11 raw ground meat samples tested yielded Listeria Seven of the ground meats had L. monocytogenes, three yielded L. innocua and one had L. welshimeri. Two thirds of the raw meat cuts harboured Listeria spp. with 44.4% (eight samples) containing L. monocytogenes. Two out of seven poultry samples yielded Listeria.Listeria were not isolated from cooked meats and raw vegetables. However, a large proportion (14.9%) of the processed packaged meat samples were found to be contaminated with L. monocytogenes.