Campylobacteriosis Agents in Meat Carcasses Collected from Two District Municipalities in the Eastern Cape Province, South Africa

Raw meats are sometimes contaminated with Campylobacter species from animal faeces, and meats have repeatedly been implicated in foodborne infections. This study evaluated the prevalence, virulence genes, antimicrobial susceptibility patterns, and resistance gene determinants in Campylobacter species isolated from retailed meat carcasses. A total of 248 raw meat samples were collected from butcheries, supermarkets, and open markets; processed for enrichment in Bolton broth; and incubated at 42 °C for 48 h in 10% CO2. Thereafter, the broths were streaked on modified charcoal cefoperazone deoxycholate agar (mCCDA) plates and incubated at the same conditions and for the same amount of time. After incubation, colonies were isolated and confirmed by Polymerase chain reaction using specific oligonucleotide sequences used for the identification of the genus Campylobacter, species, and their virulence markers. The patterns of antimicrobial resistance profiles of the identified isolates were studied by disk diffusion method against 12 antibiotics, and relevant resistance genes were assessed by PCR. From culture, 845 presumptive Campylobacter isolates were obtained, of which 240 (28.4%) were identified as genus Campylobacter. These were then characterised into four species, of which C. coli had the highest prevalence rate (22.08%), followed by C. jejuni (16.66%) and C. fetus (3.73%). The virulence genes detected included iam (43.14%), cadF (37.25%), cdtB (23.53%), flgR (18.63%), and flaA (1.96%), and some of the isolates co-harboured two to four virulence genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (100%), and the lowest level of resistance was observed against imipenem (23.33%). The frequency of resistance genes detected included catll (91.78%), tetA (68.82%), gyra (61.76%), ampC (55%), aac(3)-IIa (aacC2)a (40.98%), tetM (38.71%), ermB (18.29%), tetB (12.90%), and tetK (2.15%). There is a high incidence of Campylobacter species in meat carcasses, suggesting these to be a reservoir of campylobacteriosis agents in this community, and as such, consumption of undercooked meats in this community is a potential health risk to consumers.

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Occurrence, Virulence and Antimicrobial Resistance-Associated Markers in Campylobacter Species Isolated from Retail Fresh Milk and Water Samples in Two District Municipalities in the Eastern Cape Province, South Africa

Antibiotics ◽

10.3390/antibiotics9070426 ◽

2020 ◽

Vol 9 (7) ◽

pp. 426

Author(s):

Aboi Igwaran ◽

Anthony Ifeanyi Okoh

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Water Samples ◽

Agricultural Runoff ◽

Diffusion Method ◽

Eastern Cape Province ◽

Eastern Cape ◽

Phenotypic Resistance ◽

Milk Samples ◽

Campylobacter Species

Campylobacter species are among the major bacteria implicated in human gastrointestinal infections and are majorly found in faeces of domestic animals, sewage discharges and agricultural runoff. These pathogens have been implicated in diseases outbreaks through consumption of contaminated milk and water in some parts of the globe and reports on this is very scanty in the Eastern Cape Province. Hence, this study evaluated the occurrence as well as virulence and antimicrobial-associated makers of Campylobacter species recovered from milk and water samples. A total of 56 water samples and 72 raw milk samples were collected and the samples were processed for enrichment in Bolton broth and incubated for 48 h in 10% CO2 at 42 °C under microaerobic condition. Thereafter, the enriched cultures were further processed and purified. After which, presumptive Campylobacter colonies were isolated and later confirmed by PCR using specific primers for the detection of the genus Campylobacter, target species and virulence associated genes. Antimicrobial resistance profiles of the isolates were determined by disk diffusion method against a panel of 12 antibiotics and relevant genotypic resistance genes were assessed by PCR assay. A total of 438 presumptive Campylobacter isolates were obtained; from which, 162 were identified as belonging to the genus Campylobacter of which 36.92% were obtained from water samples and 37.11% from milk samples. The 162 confirmed isolates were further delineated into four species, of which, 7.41%, 27.16% and 8.64% were identified as C. fetus, C. jejuni and C. coli respectively. Among the virulence genes screened for, the iam (32.88%) was most prevalent, followed by flgR (26.87%) gene and cdtB and cadF (5.71% each) genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (95.68%), while the lowest was observed against imipenem (21.47%). Other high phenotypic resistance displayed by the isolates were against erythromycin (95.06%), followed by ceftriaxone (93.21%), doxycycline (87.65%), azithromycin and ampicillin (87.04% each), tetracycline (83.33%), chloramphenicol (78.27%), ciprofloxacin (77.78%), levofloxacin (59.88%) and gentamicin (56.17%). Relevant resistance genes were assessed in the isolates that showed high phenotypic resistance, and the highest resistance gene harbored by the isolates was catII (95%) gene while VIM, KPC, Ges, bla-OXA-48-like, tetC, tetD, tetK, IMI and catI genes were not detected. The occurrence of this pathogen and the detection of virulence and antimicrobial resistance-associated genes in Campylobacter isolates recovered from milk/water samples position them a risk to human health.

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Preliminary Results on the Prevalence of Salmonella Spp. in Marine Animals Stranded in Sicilian Coasts: Antibiotic Susceptibility Profile and ARGs Detection in the Isolated Strains

Pathogens ◽

10.3390/pathogens10080930 ◽

2021 ◽

Vol 10 (8) ◽

pp. 930

Author(s):

Delia Gambino ◽

Sonia Sciortino ◽

Sergio Migliore ◽

Lucia Galuppo ◽

Roberto Puleio ◽

...

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Antibiotic Susceptibility ◽

Antibiotic Resistance Genes ◽

Diffusion Method ◽

Salmonella Spp ◽

Marine Animals ◽

Disk Diffusion Method ◽

Phenotypic Resistance ◽

Low Prevalence

The presence of Salmonella spp. in marine animals is a consequence of contamination from terrestrial sources (human activities and animals). Bacteria present in marine environments, including Salmonella spp., can be antibiotic resistant or harbor resistance genes. In this study, Salmonella spp. detection was performed on 176 marine animals stranded in the Sicilian coasts (south Italy). Antibiotic susceptibility, by disk diffusion method and MIC determination, and antibiotic resistance genes, by molecular methods (PCR) of the Salmonella spp. strains, were evaluated. We isolated Salmonella spp. in three animals, though no pathological signs were detected. Our results showed a low prevalence of Salmonella spp. (1.7%) and a low incidence of phenotypic resistance in three Salmonella spp. strains isolated. Indeed, of the three strains, only Salmonella subsp. enterica serovar Typhimurium from S. coeruleoalba and M. mobular showed phenotypic resistance: the first to ampicillin, tetracycline, and sulphamethoxazole, while the latter only to sulphamethoxazole. However, all strains harbored resistance genes (blaTEM, blaOXA, tet(A), tet(D), tet(E), sulI, and sulII). Although the low prevalence of Salmonella spp. found in this study does not represent a relevant health issue, our data contribute to the collection of information on the spread of ARGs, elements involved in antibiotic resistance, now considered a zoonosis in a One Health approach.

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Phenotypic and molecular characterizations of multidrug-resistant diarrheagenic E. coli of calf origin

Animal Diseases ◽

10.1186/s44149-021-00019-3 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Shan Yue ◽

Zecai Zhang ◽

Yu Liu ◽

Yulong Zhou ◽

Chenhua Wu ◽

...

Keyword(s):

Beef Cattle ◽

Dairy Cattle ◽

Resistance Genes ◽

Virulence Genes ◽

Interaction Mechanism ◽

Multidrug Resistant ◽

Resistance Rate ◽

Diffusion Method ◽

Disk Diffusion Method ◽

E Coli

AbstractEscherichia coli has become one of the most important causes of calf diarrhea. The aim of this study is to determine the patterns of antimicrobial resistance of E. coli isolates from six cattle farms and to identify prominent resistance genes and virulence genes among the strains isolated from the diarrhea of calves. Antimicrobial susceptibility tests were performed using the disk diffusion method, and PCR was used to detect resistance and virulence genes. The prevalence of multidrug resistant (MDR) E. coli was 77.8% in dairy cattle and 63.6% in beef cattle. There were high resistance rates to penicillin (100%, 100%) and ampicillin (96.3%, 86.4%) in E. coli from dairy cattle and beef cattle. Interestingly, resistance rate to antimicrobials and distribution of resistance genes in E. coli isolated from dairy cattle were higher than those in beef cattle. Further analysis showed that the most prevalent resistance genes were blaTEM and aadA1 in dairy cattle and beef cattle, respectively. Moreover, seven diarrheagenic virulence genes (irp2, fyuA, Stx1, eaeA, F41, K99 and STa) were present in the isolates from dairy cattle, with a prevalence ranging from 3.7% to 22.22%. Six diarrheagenic virulence genes (irp2, fyuA, Stx1, eaeA, hylA and F41) were identified in the isolates from beef cattle, with a prevalence ranging from 2.27% to 63.64%. Our results provide important evidence for better exploring their interaction mechanism. Further studies are also needed to understand the origin and transmission route of E. coli in cattle to reduce its prevalence.

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Antimicrobial Resistance of EntericSalmonellain Bangui, Central African Republic

Journal of Tropical Medicine ◽

10.1155/2015/483974 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

Christian Diamant Mossoro-Kpinde ◽

Alexandre Manirakiza ◽

Jean-Robert Mbecko ◽

Pembé Misatou ◽

Alain Le Faou ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Salmonella Enterica ◽

Central African Republic ◽

Disk Diffusion ◽

Diffusion Method ◽

Clinical Samples ◽

Disk Diffusion Method ◽

Phenotypic Resistance ◽

Multiple Antibiotics

Introduction. The number ofSalmonellaisolated from clinical samples that are resistant to multiple antibiotics has increased worldwide. The aim of this study was to determine the prevalence of resistantSalmonella entericaisolated in Bangui.Methods. All entericSalmonellastrains isolated from patients in 2008 were identified and serotyped, and the phenotypes of resistance were determined by using the disk diffusion method. Nine resistance-associated genes,blaTEM,blaOXA,blaSHV,tetA,aadA1,catA1,dhfrA1,sul I, andsul II, were sought by genic amplification in sevenS.e. Typhimurium strains.Results. The 94 strains isolated consisted of 47S.e.Typhimurium (50%), 21S.e.Stanleyville (22%), 18S.e.Enteritidis (19%), 4S.e.Dublin (4%), 4S.e.Hadar (4%), and 1S.e.Papuana (1%). Twenty-five (28%) were multiresistant, including 20 of the Typhimurium serovar (80%). Two main phenotypes of resistance were found: four antibiotics (56%) and to five antibiotics (40%). OneS.e.Typhimurium isolate produced an extended-spectrumβ-lactamase (ESBL). Only seven strains ofS.e.Typhimurium could be amplified genically. Only phenotypic resistance to tetracycline and aminosides was found.Conclusion.S.Typhimurium is the predominant serovar of entericS. entericaand is the most widely resistant. The search for resistance genes showed heterogeneity of the circulating strains.

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Multidrug-Resistant Listeria Species Shows Abundance in Environmental Waters of a Key District Municipality in South Africa

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18020481 ◽

2021 ◽

Vol 18 (2) ◽

pp. 481

Author(s):

Liyabona Mpondo ◽

Kingsley Ehi Ebomah ◽

Anthony Ifeanyi Okoh

Keyword(s):

South Africa ◽

Surface Waters ◽

Multidrug Resistant ◽

Eastern Cape ◽

Environmental Waters ◽

Potential Health ◽

Phenotypic Resistance ◽

Listeria Species ◽

Polymerase Chain ◽

Identification And Characterization

The prevalence of bacteria with multidrug-resistance (MDR) is a significant threat to public health globally. Listeria spp. are naturally ubiquitous, with L. monocytogenes particularly being ranked as important foodborne disease-causing microorganisms. This study aimed to evaluate the incidence and determine the antimicrobial resistance (AMR) profiles of multidrug-resistant Listeria spp. (MDRL) isolated from different environmental samples (river and irrigation water) in the Sarah Baartman District Municipality (SBDM), Eastern Cape Province (ECP), South Africa. Molecular identification and characterization were carried out using polymerase chain reaction (PCR) and isolates that exhibited phenotypic resistance were further screened for relevant antimicrobial-resistant genes (ARGs). Findings revealed a total of 124 presumptive Listeria isolates; 69 were molecularly confirmed Listeria species. Out of the confirmed species, 41 isolates (59%) were classified as L. monocytogenes while 9 (13%) were classified as L. welshimeri. All Listeria spp. exhibited phenotypic resistance against ampicillin, penicillin, and trimethoprim-sulphamethoxazole and further screening revealed ARGs in the following proportions: sulI (71%), blaTEM (66%), tetA (63%), and blaCIT (33%). Results confirmed the occurrence of ARGs among Listeria inhabiting surface waters of ECP. The present study indicates that the river water samples collected from SBDM are highly contaminated with MDRL, hence, constituting a potential health risk.

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Prevalence of Virulence Genes and Drug Resistance Profiles of Pseudomonas aeruginosa Isolated From Clinical Specimens

Jundishapur Journal of Microbiology ◽

10.5812/jjm.118452 ◽

2021 ◽

Vol 14 (8) ◽

Author(s):

Seyed Ali Bazghandi ◽

Mohsen Arzanlou ◽

Hadi Peeridogaheh ◽

Hamid Vaez ◽

Amirhossein Sahebkar ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Drug Resistance ◽

Antibiotic Resistance ◽

Virulence Genes ◽

Virulence Gene ◽

Clinical Isolates ◽

Diffusion Method ◽

Disk Diffusion Method ◽

Clinical Specimens ◽

Resistance Rates

Background: Drug resistance and virulence genes are two key factors for the colonization of Pseudomonas aeruginosa in settings with high antibiotic pressure, such as hospitals, and the development of hospital-acquired infections. Objectives: The objective of this study was to investigate the prevalence of drug resistance and virulence gene profiles in clinical isolates of P. aeruginosa in Ardabil, Iran. Methods: A total of 84 P. aeruginosa isolates were collected from clinical specimens of Ardabil hospitals and confirmed using laboratory standard tests. The disk diffusion method was used for antibiotic susceptibility testing and polymerase chain reaction (PCR) for the identification of P. aeruginosa virulence genes. Results: The highest and the lowest antibiotic resistance rates of P. aeruginosa strains were against ticarcillin-clavulanate (94%) and doripenem (33.3%), respectively. In addition, the frequency of multidrug-resistant (MDR) P. aeruginosa was 55.9%. The prevalence of virulence factor genes was as follows: algD 84.5%, lasB 86.9%, plcH 86.9%, plcN 86.9%, exoU 56%, exoS 51.2%, toxA 81%, nan1 13.1%, and pilB 33.3%. A significant association was observed between resistance to some antibiotics and the prevalence of virulence genes in P. aeruginosa. Conclusions: Our results revealed a high prevalence of antibiotic resistance, especially MDR, and virulence-associated genes in clinical isolates of P. aeruginosa in Ardabil hospitals. Owing to the low resistance rates against doripenem, gentamicin, and tobramycin, these antibiotics are recommended for the treatment of infections caused by highly resistant and virulent P. aeruginosa strains.

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Virulence Gene Profile, Antimicrobial Resistance and Multilocus Sequence Typing of Salmonella enterica Subsp. enterica Serovar Enteritidis from Chickens and Chicken Products

Animals ◽

10.3390/ani12010097 ◽

2022 ◽

Vol 12 (1) ◽

pp. 97

Author(s):

Zunita Zakaria ◽

Latiffah Hassan ◽

Zawiyah Sharif ◽

Norazah Ahmad ◽

Rohaya Mohd Ali ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Multilocus Sequence Typing ◽

Salmonella Enteritidis ◽

Molecular Subtypes ◽

Actin Binding ◽

Diffusion Method ◽

Genetic Characteristics ◽

Meat Samples ◽

Sequence Types

This study was undertaken to determine the virulence, antimicrobial resistance and molecular subtypes of Salmonella in the Central Region of Peninsular Malaysia. A total of 45 Salmonella Enteritidis were detected from live chicken (cloacal swab), and chicken products (fresh and ready-to-eat meat) samples upon cultural isolation and serotyping. Similarly, an antimicrobial susceptibility test based on the Kirby Bauer disk diffusion method as well as antimicrobial resistance AMR genes, virulence determinants and multilocus sequence typing (MLST) typing were conducted after the Whole Genome Sequencing and analysis of the isolates. The results indicate that sequence types ST1925 (63.7%), and ST11 (26.5%) were the predominant out of the seven sequence types identified (ST292, ST329, ST365, ST423 and ST2132). The phenotypic antimicrobial profile corresponds to the genotypic characterization in that the majority of the isolates that exhibited tetracycline, gentamycin and aminoglycoside resistance; they also possessed the tetC and blaTEM β-Lactam resistance genes. However, isolates from cloacal swabs showed the highest number of resistance genes compared to the chicken products (fresh and ready-to-eat meat) samples. Furthermore, most of the virulence genes were found to cluster in the Salmonella pathogenicity island (SPI). In this study, all the isolates were found to possess SPI-1, which codes for the type III secretion system, which functions as actin-binding proteins (SptP and SopE). The virulence plasmid (VP) genes (spvB, spvC) were present in all genotypes except ST365. The findings of this study, particularly with regard to the molecular subtypes and AMR profiles of the Salmonella Enteritidis serotype shows multidrug-resistance features as well as genetic characteristics indicative of high pathogenicity.

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Prevalence and Antibiograms of Salmonella in Commercially Produced Crocodile meat in Zimbabwe

Tanzania Veterinary Journal ◽

10.4314/tvj.v36i1.1 ◽

2021 ◽

Vol 36 (1) ◽

pp. 1-14

Author(s):

A.Z. Nhidza ◽

C. Gufe ◽

J. Marumure ◽

Z. Makuvara ◽

T. Chisango ◽

...

Keyword(s):

Hazard Analysis ◽

Control Point ◽

Penicillin G ◽

Diffusion Method ◽

Biochemical Tests ◽

Disk Diffusion Method ◽

Critical Control Point ◽

Meat Samples ◽

Low Prevalence ◽

Susceptibility Profiles

The presence of Salmonella in food products and emergence of antibiotic resistance are the major challenges facing public health policies. A total of 2749 crocodile meat samples obtained from the Central Veterinary Laboratories in Zimbabwe were screened for Salmonella specieswere collected from three Zimbabwean commercial farms between the year 2012 and 2019 for a retrospective observational study to determine the prevalence and magnitude of antibiotics resistant Salmonella species in crocodile meat. The isolation of Salmonella was in accordance with the ISO 6579:2002 and the antibiotic susceptibility testing was carried out based on Clinical and Laboratory Standard Institute’s recommendations by means of the Kirby-Bauer disk diffusion method. SILAB Database was used to determine the prevalence of Salmonella species. Prevalence was stratified by year and farms. Twenty Salmonella isolates were identified using biochemical tests, and 15 were confirmed by polymerase chain reaction (PCR). Antimicrobial susceptibility profiles of the confirmed Salmonella isolates were examined using 14 antibiotics. The overall prevalence of Salmonella species in crocodile meat samples was 0.5%. The prevalence of Salmonella species ranged from 0.04% to 0.44% in the crocodile meat samples and annual prevalence ranged from 0.01% to 1%. The highest prevalence of Salmonella (4.4%) was recorded in the year 2012. Salmonella isolates from one of the three tested farms were resistant to Erythromycin (73.33%), Ampicillin (80%), and Penicillin G (100%). Generally, Salmonella isolates displayed lower resistance to Cefepime, Ceftriaxone, Amikacin, Tetracycline, Ertapenem, Florfenicol, and Erythromycin (0-53.33%) whereas all Salmonella isolates showed susceptibility to Cefepime, Ceftriaxone, Ertapenem, and Florfenicol. Although the study indicates low prevalence of Salmonella species in crocodile meat, there is a need for strict implementation of Hazard Analysis Critical Control Point (HACCP) to reduce contamination rates in meat and its products

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Emerging MDR-Pseudomonas aeruginosa in fish commonly harbor oprL and toxA virulence genes and blaTEM, blaCTX-M, and tetA antibiotic-resistance genes

Scientific Reports ◽

10.1038/s41598-020-72264-4 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 4

Author(s):

Abdelazeem M. Algammal ◽

Mahmoud Mabrok ◽

Elayaraja Sivaramasamy ◽

Fatma M. Youssef ◽

Mona H. Atwa ◽

...

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Virulence Genes ◽

Antibiotic Resistance Genes ◽

Health Concern ◽

Diffusion Method ◽

Multi Drug Resistance ◽

Fish Farms ◽

M Gene ◽

Total Prevalence

Abstract This study aimed to investigate the prevalence, antibiogram of Pseudomonasaeruginosa (P.aeruginosa), and the distribution of virulence genes (oprL,exoS, phzM, and toxA) and the antibiotic-resistance genes (blaTEM, tetA, and blaCTX-M). A total of 285 fish (165 Oreochromisniloticus and 120 Clariasgariepinus) were collected randomly from private fish farms in Ismailia Governorate, Egypt. The collected specimens were examined bacteriologically. P. aeruginosa was isolated from 90 examined fish (31.57%), and the liver was the most prominent infected organ. The antibiogram of the isolated strains was determined using a disc diffusion method, where the tested strains exhibited multi-drug resistance (MDR) to amoxicillin, cefotaxime, tetracycline, and gentamicin. The PCR results revealed that all the examined strains harbored (oprL and toxA) virulence genes, while only 22.2% were positive for the phzM gene. On the contrary, none of the tested strains were positive for the exoS gene. Concerning the distribution of the antibiotic resistance genes, the examined strains harbored blaTEM, blaCTX-M, and tetA genes with a total prevalence of 83.3%, 77.7%, and 75.6%, respectively. Experimentally infected fish with P.aeruginosa displayed high mortalities in direct proportion to the encoded virulence genes and showed similar signs of septicemia found in the naturally infected one. In conclusion, P.aeruginosa is a major pathogen of O.niloticus and C.gariepinus.oprL and toxA genes are the most predominant virulence genes associated with P.aeruginosa infection. The blaCTX-M,blaTEM, and tetA genes are the main antibiotic-resistance genes that induce resistance patterns to cefotaxime, amoxicillin, and tetracycline, highlighting MDR P.aeruginosa strains of potential public health concern.

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Prevalence and antimicrobial resistance of Listeria species and molecular characterization of Listeria monocytogenes isolated from retail ready-to-eat foods

FEMS Microbiology Letters ◽

10.1093/femsle/fnaa006 ◽

2020 ◽

Vol 367 (4) ◽

Author(s):

Seza Arslan ◽

Fatma Özdemir

Keyword(s):

Antimicrobial Resistance ◽

Genetic Relatedness ◽

Fragment Length Polymorphism ◽

Food Samples ◽

Diffusion Method ◽

Consumer Health ◽

Disk Diffusion Method ◽

Listeria Species ◽

Virulence Markers

ABSTRACT A wide variety of foods can be contaminated with Listeria species, especially L. monocytogenes. Ready-to-eat (RTE) foods are predominantly associated with human listeriosis caused by L. monocytogenes. Therefore, this study aimed to assess the presence of Listeria species in RTE foods and to characterize L. monocytogenes isolates by means of detection of virulence markers, serotypes and genetic relatedness. Of the 300 RTE food samples, 59 (19.7%) were positive for Listeria species: L. innocua (13.3%), L. monocytogenes (5%), L. welshimerii (2.3%), L. grayi subsp. murrayi (1.3%), L. grayi (1%), L. ivanovii (1%) and L. ivanovi subsp. londoniensis (0.3%). All L. monocytogenes isolates identified were positive for the actA, iap, inlA, inlB, inlC, inlJ, plcA and prfA virulence genes and biofilm. The isolates were serotyped as 1/2c (33.3%), 4b (26.7%), 1/2a (26.7%), 1/2b (6.7%) and 3c (6.7%) by the multiplex-PCR and agglutination methods. PCR-restriction fragment length polymorphism with AluI and MluCI resulted in three and two profiles, respectively. Pulsed-field gel electrophoresis differentiated the L. monocytogenes isolates into 15 ApaI and 12 AscI patterns. Antimicrobial resistance of all Listeria isolates was determined by the disk diffusion method. Most L. monocytogenes isolates were sensitive to antimicrobials used in the treatment of listeriosis. This study shows the presence of potential pathogenic and antimicrobial-resistant L. monocytogenes in RTE foods that may lead to consumer health risks.

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