Identification of Listeria species and Multilocus Variable-Number Tandem Repeat Analysis (MLVA) Typing of Listeria innocua and Listeria monocytogenes Isolates from Cattle Farms and Beef and Beef-Based Products from Retail Outlets in Mpumalanga and North West Provinces, South Africa

Abstract

In this study, Listeria isolates (214) were characterized as follows: L. innocua (77.10%), L. monocytogenes (11.21%), L. welshimeri (5.61%), L. grayi (1.40%), L. seeligeri (0.93%), and L. species (3.73%) that were not identified at the species level, from beef and beef based products from retail and farms in Mpumalanga and North West provinces of South Africa. MLVA was further used to type Listeria innocua isolates (165) and Listeria monocytogenes isolates (24). The L. monocytogenes isolates were also serogrouped using PCR. The MLVA protocol for L. monocytogenes typing included six tandem repeat primer sets, and the MLVA protocol for L. innocua included the use of three tandem repeats primer sets. The L. monocytogenes serogroups were determined as follows: 4b-4d-4e (IVb) (37.50%), 1/2a-3a (IIa) (29.16%), 1/2b-3b (IIb) (12.50%), 1/2c-3c (IIc) (8.33%), and IVb-1 (4.16%). MLVA could cluster isolates belonging to each specie, L. monocytogenes, and L. innocua isolates, into MLVA-related strains. There were 34 and 10 MLVA types obtained from the MLVA typing of L. innocua and L. monocytogenes, respectively. MLVA clustered the L. monocytogenes isolates irrespective of sample category, serogroups, and geographical origin. Similarly, the L. innocua isolates clustered irrespective of meat category and geographical origin. MLVA was able to cluster isolates based on MLVA relatedness. The clustering of isolates from farms and retailers indicates transmission of Listeria spp. MLVA is an affordable, simple, and discriminatory method that can be used routinely to type L. monocytogenes and L. innocua isolates.

Genomic Characterization of Listeria innocua Isolates Recovered from Cattle Farms, Beef Abattoirs, and Retail Outlets in Gauteng Province, South Africa

“…Between 2017 and 2018, South Africa experienced the world’s largest outbreak of human listeriosis, caused by ‘polony’, a ready-to-eat (RTE) beef product [ 31 ], and L. monocytogenes ST6 was determined to be the etiological agent [ 21 ]. A few studies using polymerase chain reaction (PCR) have characterized L. monocytogenes strains recovered from meat and meat products across the country [ 32 ] and MLVA genotypes of Listeria monocytogenes and L. innocua isolated from farms, abattoirs, and retail in Gauteng province [ 33 ], Mpumalanga province, and North–West province [ 34 ]. To the best of our knowledge, there is a dearth of information on the genomic characteristics of L. innocua strains in the country.…”

Contamination of beef and beef products by Listeria spp. and molecular characterization of L. monocytogenes in Mpumalanga, South Africa

“…innocua (El‐Zowalaty et al, 2019; Makumbe, Tabit, & Dlamini, 2021), and L . welshimeri (Manqele, Gcebe, Pierneef, Moerane, & Adesiyun, 2023) have been documented as occurring in humans, foods and environmental sources in South Africa.…”

“…The genus Listeria currently includes 27 recognized species, but only two species, L. monocytogenes, and L. ivanovii, are considered pathogens (El Hag, El Zubeir, & Mustafa, 2021;Ledlod, Bunroddith, Areekit, Santiwatanakul, & Chansiri, 2020). To date, only L. monocytogenes (Gana, Gcebe, Pierneef, Moerane, & Adesiyun, 2022;Kayode & Okoh, 2022), L. innocua (El-Zowalaty et al, 2019;Makumbe, Tabit, & Dlamini, 2021), and L. welshimeri (Manqele, Gcebe, Pierneef, Moerane, & Adesiyun, 2023) have been documented as occurring in humans, foods and environmental sources in South Africa.…”

A review of the literature of Listeria monocytogenes in Africa highlights breast milk as an overlooked human source

“…To control food safety and prevent listeriosis infection or epidemics in African countries, studies have been conducted on several food products (ready-to-eat foods, cold cuts, dairy products, vegetables). LMO has been detected in meat products (beef, sheep and pork) in Nigeria ( Ikeh et al, 2010 ; Adetunji and Isola, 2011 ), South Africa ( Matle et al, 2019 , 2020 ; Thomas et al, 2020 ; Magqupu et al, 2023 ; Manqele et al, 2023 ), Egypt ( Yehia et al, 2016 ), Botswana ( Morobe, 2009 ), Ethiopia ( Gebretsadik et al, 2011 ), and Morocco ( Cohen et al, 2008 ). It has also been detected in poultry in Nigeria ( Okwori et al, 2011 ), Egypt ( Yehia et al, 2016 ), Ethiopia ( Gebretsadik et al, 2011 ) and South Africa ( van Nierop et al, 2005 ) as well as in ready-to-eat foods in South Africa ( Matle et al, 2019 ), Tunisia ( Hmaïed et al, 2014 ), Morocco ( Cohen et al, 2008 ) and Nigeria ( Kawo and Bello, 2016 ), leafy vegetables in Nigeria ( Mawak et al, 2009 ; Kawo and Bello, 2016 ; Nwaiwu, 2016 ; Miyebi et al, 2018 ) and Botswana ( Morobe, 2009 ), fish (smoked and processed) in Nigeria ( Chukwu et al, 2006 ) and Egypt ( Yehia et al, 2016 ), and in ice cream and cakes in Ethiopia ( Gebretsadik et al, 2011 ; Figure 3 ).…”