<i>Listeria monocytogenes</i> isolates from Western Cape, South Africa exhibit resistance to multiple antibiotics and contradicts certain global resistance patterns

Abstract

Food-borne disease outbreaks are common and offer valuable insights into the causes, impacts, and mechanisms underlying food pathogens. This also serves as a good foundation to validate the performance of current best practice control methods, for example antibiotics, that are used in the fight against food pathogens. Listeriosis outbreaks, caused by Listeria monocytogenes , is no exception. In 2018, South Africa experienced the largest global listeriosis outbreak recorded to date. However, despite the scale of this outbreak, information on the bacterium and its resistance towards antibiotics is still severely lacking. Furthermore, until now it remained to be determined whether L. monocytogenes antibiotic resistance patterns in South Africa mirror resistance patterns elsewhere in the world. The aim of this study was therefore to evaluate the efficacy of antibiotics that are currently used against L. monocytogenes . Using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disc diffusion method, L. monocytogenes isolates (n = 177) from diverse origins in the Western Cape, South Africa (clinical, food, and environment) were tested for susceptibility against five different antibiotics, namely ampicillin, erythromycin, chloramphenicol, gentamicin, and tetracycline. Isolates were collected over a period of two years (2017–2019). All isolates were susceptible to ampicillin, the currently recommended antibiotic, while a large number of isolates were resistant to chloramphenicol, erythromycin, and tetracycline. Also, patterns of resistance observed here are different to patterns observed elsewhere. The findings of this study demonstrate that it is imperative to continuously monitor the efficacy of currently recommended antibiotics, since resistance patterns can quickly develop when such antibiotics are overutilized, and secondly, that it is crucial to assess local antibiotic resistance patterns in conjunction with global patterns, since the latter is not necessarily generalizable to local scales.

Antimicrobial Resistance of Listeria monocytogenes Strains Isolated from Humans, Animals, and Food Products in Russia in 1950–1980, 2000–2005, and 2018–2021

“…MAR strains described in this work were isolated in 2005-2019 suggesting that the spread of multidrug resistance in Russia has similar or even slower dynamics as in other countries (Table 3). The noticeable increase in the spread of antibiotic determinants was observed by some authors with the incidence of MAR strains reaching 30% or more in the last 10 years especially among environmental, animal and food isolates [43][44][45]. Our results on MAR strains' occurrence in food products and clinical cases in 2018-2021 do not support this observation for L. monocytogenes isolated in Russia.…”

Occurrence of Multidrug-Resistant Listeria monocytogenes in Environmental Waters: A Menace of Environmental and Public Health Concern

“…Susceptibilities to imipenem and vancomycin in our study were lower compared to the report of Manjur et al (2018). Lm isolates showed varying percentages of resistance against all antibiotics tested except ampicillin for which no resistance was recorded similar to the report by Keet and Rip, (2021). High resistance rates against sulfamethoxazole (63.16%), oxytetracycline (54.39%), and amoxicillin (50.88%) were observed.…”

Probing antimicrobial resistance and sanitizer tolerance themes and their implications for the food industry through the Listeria monocytogenes lens

“…Food and environmental L. monocytogenes studies frequently report susceptibility of isolates to antibiotics used in listeriosis treatment; however, cases of intermediate and resistant phenotypes to a number of clinically relevant antibiotics continue to be seen globally. Common examples of resistant phenotypes among food chain L. monocytogenes include isolates resistant to chloramphenicol, ciprofloxacin, clindamycin, penicillin, and tetracyclines (Table 4; Jorgensen et al., 2021; Keet & Rip, 2021; Kovacevic et al., 2013; Noll et al., 2018; Roedel et al., 2019), while resistance to erythromycin, gentamicin, and rifampicin is less commonly reported (Keet & Rip, 2021; Roedel et al., 2019; Wilson et al., 2018).…”

“…While prevalence alone provides important insight into persistence and contamination events, evaluation of antibiotic resistance through antibiogram characterization within these isolates aids in understanding the public health risk associated with L. monocytogenes collected from the farm-tofork continuum. Food and environmental Kovacevic et al, 2013;Noll et al, 2018;Roedel et al, 2019), while resistance to erythromycin, gentamicin, and rifampicin is less commonly reported (Keet & Rip, 2021;Roedel et al, 2019;Wilson et al, 2018).…”

“…resistant phenotypes to a number of clinically relevant antibiotics continue to be seen globally. Common examples of resistant phenotypes among food chain L. monocytogenes include isolates resistant to chloramphenicol, ciprofloxacin, clindamycin, penicillin, and tetracyclines (Table4;Jorgensen et al, 2021;Keet & Rip, 2021; …”