The occurrence and the antibiogram signatures of Listeria monocytogenes (Lm) recovered from 65 milk samples and its products within the Eastern Cape province were examined. The EN ISO 11290:2017 procedures Parts 1 and 2 described by the International Organization for Standardization for the enumeration and isolation of Lm was adopted for the study. Lm was detected in 18.46% of all the samples examined, and the strains recovered from the samples belong to serotypes 4b and 1/2b. The virulence determinants including prfA, plcA, plcB, inlA, inlC, hly, mpl, actA, inlJ and inlB were detected in all the isolates. About 95.24% of the studied Lm isolates demonstrated potential capacity for biofilm formation. The antibiogram profile revealed high resistance against sulfamethoxazole (71.43%), trimethoprim (52.86%); erythromycin, cefotetan and oxytetracycline (42.86% respectively). About 85.71% exhibited multiple antibiotic resistance phenotypes against the test antibiotics. The resistance determinants encoding resistance against the β-lactamase antibiotics [such as the bla_TEM, bla_SHV, bla_TEM variants (TEM-1 and TEM-2) and the bla_Z], the tetracycline resistance genes (including tetA, tetD, tetG and tetM and tetK) were detected among resistant isolates. In addition, the aminoglycoside resistance gene aph (3)-IIa (aphA2)^a was detected only in one isolate. Finally, the sulfonamide resistance genes including the sul2 and the sul1 genes were the most frequently observed among Lm isolates. Generally, 71.43% of all Lm isolates recovered from the samples investigated harboured one or more resistance genes encoding resistance against various antibiotics. The antibiogram signatures of Lm isolates observed in this study is an indication that empirical treatment of listeriosis may be challenging in the future as the pathogen may obliterate the success of antibiotics. We, therefore, advocate for the recognition of the One Health approach to ensuring food safety and curbing the spread of antimicrobial resistance in food.

The occurrence and antibiogram profiles ofListeria monocytogenesin environmental waters in the Eastern Cape Province, South Africa, were investigated. Seventy-eight samples from rivers, wastewater, and irrigation water were collected at different geographical locations within the province from February to September 2019. The procedure of the International Organization for Standardization EN ISO 11290:2017 part 1 and 2 was adopted for the isolation of Lm. The counts of presumptive Lm ranged from 2.0 × 10³ CFU/100 ml to 3.6 × 10⁵ CFU/100 ml. About 39.74% of the samples were positive for Lm, and the isolates were confirmed as serotype 1/2a (78.95%) and serotype 4b (21.05%). About 68.42% of the isolates demonstrated biofilm-forming potentials. Ten virulence determinants including theplcA, inlA, andinlBwere detected in all the isolates; however,inlC(85.97%),inlJ(80.70%),actA(59.65%),prfA(92.98%),plcB(89.47%),hly(80.70%), andmpl(73.68%) were less prevalent. The antibiogram profiles of confirmed Lm isolates revealed high susceptibilities (>50%) to all antibiotics ranging from 52.63% (cefotetan) to 100% (ampicillin) except for sulfamethoxazole (35.09%), erythromycin (26.32%), streptomycin (38.60%), oxytetracycline (45.61%), and amoxicillin (49.12%). Conversely, high resistance rates against sulfamethoxazole (63.16%), oxytetracycline (54.39%), and amoxicillin (50.88%) were observed. Isolates exhibited 52 resistance patterns against 22 antibiotics tested ranging from 1 to 15 antibiotics, and 82.46% showed multidrug-resistance phenotypes against the antibiotics. The antibiotic resistance index (ARI) of river water (0.18) was less than the permissible (0.2) Krumperman threshold, whereas that of irrigation and wastewater were higher than the Krumperman threshold. The multiple/antibiotic resistance index ((M)ARI) of each of the isolates ranged from 0.05–0.68. Resistance determinants (21) encoding resistance against sulphonamides, β-lactamase, phenicols, aminoglycosides, and tetracyclines were detected among the phenotypically resistant Lm isolates investigated which justifies the phenotypic resistance observed in this study. The abundance of resistance determinants in Lm recovered from environmental waters in this study suggests that the aquatic environments may serve as a channel for the dissemination of antimicrobial-resistant Lm to other niches including the food chain.

Listeriosis is rarely reported in the Southern African Hemispheres in spite of the increasing rate ofListeriain several foodborne outbreaks reported in advanced countries. This paper reviews the emerging trends in the spread, distribution, and epidemiology ofListeriaspecies in foods, water, human, animals, and different environments in Southern Africa based on the appraisal of scholarly articles. In this regard, information obtained from literatures from various online databases revealed thatListeriaspecies are commonly recovered from food, water, and human samples. Fewer articles provided information onListeriarecovered from animals (ruminants) and soil samples. Generally, reports of studies were more focused onListeria monocytogenesamong otherListeriaspecies. To this end, reports obtained from literature on the method of identification ofListeriawere mostly based on serological, classical biochemical methods and the principle of aesculin hydrolysis, usually characterized by black coloration on selective media forListeria. These methods may not be reliable, as they could sometimes give a false positive report. Therefore, molecular methods are more reliable, accurate, could show the genetic relationship between isolates, and at the same time capable of enabling tracking the source of this pathogen should be embraced as a better substitute for the identification ofListeriain Southern African sub‐region.

In recent decades, there has been an increase in the reports of antimicrobial resistance of Listeria monocytogenes (Lm) constituting a serious threat to the therapeutic management of listeriosis infection. Our study profiled the antibiogram fingerprint of Lm isolates (n = 194) recovered from common South African ready-to-eat (RTE) foods. Lm isolates recovered from foods were tested against a panel of 22 antibiotics using the disc diffusion techniques. Antimicrobial resistance (> 50 %) against ceftriaxone (53.1 %), trimethoprim (56.2 %), streptomycin, cefotetan (59.3 %), sulfamethoxazole (61.9 %), vancomycin and oxytetracyclines (62.9 %) were observed. Thirty of the isolates (15.5 %) were resistant against only one or two antibiotics, while 162 (83.5 %) exhibited phenotypic multiple antibiotic resistance. Only two (n = 2, 1 %) of the isolates did not exhibit phenotypic resistance against any antibiotics screened. Multiple antibiotic phenotypes (MARPs) revealed high resistance patterns and the multiple antibiotic indices were greater than the Krumperman permissible (> 0.2) benchmark. Twenty-two (22) antimicrobial resistance genes (ARGs) were detected among RTE food isolates including resistance determinants that encode sulfonamides (n = 125, 64.4%), beta-lactams (n = 86, 44.3 %), phenicols (n = 25, 12.9), aminoglycosides (n = 93, 47.9 %) resistance out of the 44 genes screened. We conclude that the presence of resistant Lm isolates harbouring corresponding ARGs in foods could compromise safety and constitute severe health consequences if consumed. ?

Antimicrobial resistance is an existential threat to the health sector, with far-reaching consequences in managing microbial infections. In this study, one hundred and ninety-four Listeria monocytogenes isolates were profiled for susceptibility using disc diffusion techniques. Possible foodborne listeriosis risk associated with ready-to-eat (RTE) foods (RTEF) and the risk of empirical treatment (EMPT) of L. monocytogenes infections, using multiple antimicrobial resistance indices (MARI) and antimicrobial resistance indices (ARI), respectively, were investigated. Twelve European Committee on Antimicrobial Susceptibility Testing (EUCAST) prescribed/recommended antimicrobials (EPAS) for the treatment of listeriosis and ten non-prescribed antimicrobials (non-PAS)] were evaluated. Antimicrobial resistance > 50% against PAs including sulfamethoxazole (61.86%), trimethoprim (56.19%), amoxicillin (42.27%), penicillin (41.24%), and erythromycin (40.21%) was observed. Resistance > 50% against non-PAS, including oxytetracycline (60.89%), cefotetan (59.28%), ceftriaxone (53.09%), and streptomycin (40.21%) was also observed. About 55.67% and 65.46% of the isolates had MARI scores ranging from 0.25–0.92 and 0.30–0.70 for EPAs and non-PAs, respectively. There was a significant difference (p < 0.01) between the MARI scores of the isolates for EPAs and non-PAs (means of 0.27 ± 0.21 and 0.31 ± 0.14, respectively). MARI/ARI scores above the Krumperman permissible threshold (>0.2) suggested a high risk/level of antimicrobial-resistant L. monocytogenes. The MARI risks of the non-success of empirical treatment (EMPT) attributed to EPAs and non-PAs were generally high (55.67% and 65.463%, respectively) due to the antimicrobial resistance of the isolates. MARI-based estimated success and non-success of EMPT if EUCAST-prescribed antimicrobials were administered for the treatment of listeriosis were 44.329% and 55.67%, respectively. The EMPT if non-prescribed antimicrobials were administered for the treatment of listeriosis was 34.53% and 65.46%, respectively. This indicates a potentially high risk with PAs and non-PAs for the treatment of L. monocytogenes infection. Furthermore, ARI scores ≤ 0.2 for EPAs were observed in polony, potato chips, muffins, and assorted sandwiches, whereas ARI scores for non-PAs were >0.2 across all the RTE food types. The ARI-based estimate identified potential risks associated with some RTE foods, including fried fish, red Vienna sausage, Russian sausage, fruit salad, bread, meat pies, fried chicken, cupcakes, and vetkoek. This investigation identified a high risk of EMPT due to the presence of antimicrobial-resistant L. monocytogenes in RTE foods, which could result in severe health consequences.

The outbreak of the 2019 coronavirus pandemic caught the world by surprise in late 2019 and has held it hostage for months with an increasing number of infections and deaths. Although coronavirus was first discovered in the 1960s and was known to cause respiratory infection in humans, no information was available about the epidemic pattern of the virus until the past two decades. This review addresses the pathogenesis, transmission dynamics, diagnosis, management strategies, the pattern of the past and present events, and the possibility of future outbreaks of the endemic human coronaviruses. Several studies have described bats as presumptive natural reservoirs of coronaviruses. In essence, the identification of a diverse group of similar SARS coronaviruses in bats suggests the possibility of a future epidemic due to severe acute respiratory syndrome (SARS-like) coronaviruses originating from different reservoir hosts. The study also identified a lack of vaccines to prevent human coronavirus infections in humans in the past, however, the recent breakthrough in vaccine discovery and approval for emergency use for the treatment of Severe Acute Respiratory Syndrome Coronavirus 2 is commendable. The high rates of genomic substitution and recombination due to errors in RNA replication and the potential for independent species crossing suggest the chances of an entirely new strain evolving. Therefore, rapid research efforts should be deployed for vaccination to combat the COVID-19 pandemic and prevent a possible future outbreak. More sensitization and enlightenment on the need to adopt good personal hygiene practices, social distancing, and scientific evaluation of existing medications with promising antiviral effects against SARS-CoV-2 is required. In addition, intensive investigations to unravel and validate the possible reservoirs, the intermediate host, as well as insight into the ability of the virus to break the species barrier are needed to prevent future viral spillover and possible outbreaks.