Multiplex PCR method for the detection of human norovirus, Salmonella spp., Shigella spp., and shiga toxin producing Escherichia coli in blackberry, coriander, lettuce and strawberry

A study of imported unprepared whole lettuces sampled from supermarkets, greengrocers, shops, and market stalls found that all were of acceptable microbiological quality. Twenty-seven out of 151 (18%) imported lettuce samples had Enterobacteriaceae levels of 104 CFU/g or more. However, these bacteria that constitute part of the natural microflora of unprepared vegetables may also be derived from the soil and/or by poor handling. The pathogens, Salmonella spp., Shigella spp., Campylobacter spp., Escherichia coli O157:H7, Vibrio cholerae, Listeria monocytogenes, and also Escherichia coli, an indicator of fecal contamination, were not detected in any imported lettuces, indicating that hygiene, harvesting, and production practices were good. Imported lettuces with Enterobacteriaceae levels of 104 CFU/g or more varied with type of retail premises and the temperature at which the lettuces were displayed. Samples from greengrocers, shops, and market stalls were more likely to contain Enterobacteriaceae at levels in excess of 104 CFU/g than those from supermarkets.

Download Full-text

Low Prevalence of Salmonella and Shiga Toxin–Producing Escherichia coli in Lymph Nodes of Australian Beef Cattle

Journal of Food Protection ◽

10.4315/0362-028x.jfp-17-180 ◽

2017 ◽

Vol 80 (12) ◽

pp. 2105-2111 ◽

Cited By ~ 3

Author(s):

Gavin Bailey ◽

Long Huynh ◽

Lachlan Govenlock ◽

David Jordan ◽

Ian Jenson

Keyword(s):

Escherichia Coli ◽

Lymph Nodes ◽

Shiga Toxin ◽

Limit Of Detection ◽

Ground Beef ◽

Plate Count ◽

Salmonella Spp ◽

Live Animal ◽

E Coli ◽

Low Prevalence

ABSTRACT Salmonella contamination of ground beef has been viewed as originating from the surface of carcasses. Recent studies have identified lymph nodes as a potential source of Salmonella contamination because these tissues play an active role in containment of pathogens in the live animal and because some lymph nodes are unavoidably present in manufacturing beef trimmings or primal cuts that may be incorporated into ground beef. A survey was conducted of the microbiological status of lymph nodes from Australian cattle at the time of slaughter to determine the prevalence of microbiological contamination. Sets of lymph nodes (n = 197), consisting of the superficial cervical (prescapular), prepectoral, axillary, presternal, popliteal, ischiatic, subiliac (precrural), coxalis, and iliofemoralis (deep inguinal), were collected from five geographically separated Australian abattoirs over a period of 14 months. Samples were tested for the presence of Salmonella spp. and Shiga toxin–producing Escherichia coli by BAX PCR assay. Aerobic plate count, E. coli, and coliforms were enumerated with a lower limit of detection of 80 CFU per node. The observed prevalence of Salmonella within peripheral lymph nodes was 0.48% (7 of 1,464). Two of the seven lymph nodes in which Salmonella organisms were detected came from the same animal. Grass-fed, grain-fed, and cull dairy cattle were all found to have detectable Salmonella in lymph nodes. All Salmonella detections occurred during cooler months of the year. No Shiga toxin–producing E. coli were detected. Aerobic microorganisms were detected above the limit of quantification in 3.2% of nodes (median count 2.24 log per node), and E. coli was detected in 0.8% of nodes (median count 3.05 log per node). The low prevalence of Salmonella and low concentration of aerobic microorganisms in Salmonella-positive lymph nodes of Australian cattle at the time of slaughter suggest that the likelihood of lymph nodes contributing significantly to the presence of Salmonella in ground beef is low.

Download Full-text

Implementation of multiplex PCR diagnostics for gastrointestinal pathogens linked to increase of notified Shiga toxin-producing Escherichia coli cases in Norway, 2007–2017

European Journal of Clinical Microbiology & Infectious Diseases ◽

10.1007/s10096-019-03475-5 ◽

2019 ◽

Vol 38 (4) ◽

pp. 801-809 ◽

Cited By ~ 6

Author(s):

Gaute Reier Jenssen ◽

Lamprini Veneti ◽

Heidi Lange ◽

Line Vold ◽

Umaer Naseer ◽

...

Keyword(s):

Escherichia Coli ◽

Multiplex Pcr ◽

Shiga Toxin ◽

Gastrointestinal Pathogens ◽

Pcr Diagnostics

Download Full-text

Molecular Strategies for the Detection, Identification, and Differentiation between Enteroinvasive Escherichia coli and Shigella spp.

Journal of Food Protection ◽

10.4315/0362-028x-68.2.239 ◽

2005 ◽

Vol 68 (2) ◽

pp. 239-245 ◽

Cited By ~ 29

Author(s):

CESAR I. BIN KINGOMBE ◽

MARIA-LUCIA CERQUEIRA-CAMPOS ◽

JEFFREY M. FARBER

Keyword(s):

Escherichia Coli ◽

Multiplex Pcr ◽

Shigella Flexneri ◽

Shigella Dysenteriae ◽

Shigella Boydii ◽

Epidemiological Tool ◽

Pcr Rflp ◽

Shigella Spp

A strategy for the detection, identification, and differentiation of enteroinvasive Escherichia coli (EIEC) and Shigella spp. has been developed. The strategy includes (i) a multiplex PCR for the amplification of two virulence genes, i.e., iuc (222 bp) and ipaH (629 bp); (ii) amplification of the ial gene (a 1,038-bp amplicon) located within a large plasmid; and (iii) restriction fragment length polymorphism (RFLP) of the ial gene amplicon. The multiplex PCR provided three patterns. Pattern 1 (iuc−/ipaH+) was found in 10 (67%) of 15 EIEC strains tested, pattern 2 (iuc+/ipaH−) in only 2 (4.4%) of 46 non-EIEC isolates, whereas pattern 3 (iuc+/ipaH+) was observed in all Shigella spp. and also in 5 (33%) of 15 EIEC strains tested. The pattern 3 EIEC strains were all positive for the ial gene. The PCR-RFLP of the ial gene amplicon using the endonuclease AclI was used to differentiate Shigella spp. from the EIEC strains that belonged to pattern 3. The ial gene was present in 21 (38%) of 56 and 6 (40%) of 15 Shigella spp. and EIEC strains tested, respectively. The PCR-RFLP of the ial gene amplicon divided the strains in two types. Type 1 did not contain the restriction enzyme site and was found in 6 (100%) of 6 EIEC strains, 4 (80%) of 5 Shigella boydii, and 4 (100%) of 4 Shigella dysenteriae strains tested. Type 2, which gave two fragments of 286 and 752 bp, was observed in 5 (83%) of 6 Shigella flexneri strains and 6 (100%) of 6 Shigella sonnei strains. Detection, identification, and differentiation of Shigella spp. and EIEC were achieved by analyses of the PCR patterns and RFLP types. To our knowledge, this is the first study to demonstrate a simple and rapid method for detecting, identifying, and differentiating, at the molecular level, Shigella spp. and EIEC strains. This method will have tremendous utility as an epidemiological tool and in helping to develop policies, risk assessments, and national and international methods for Shigella spp.

Download Full-text