Category Archives: Antibiotic Resistance

Research – FAO and the Republic of Korea join forces to reduce foodborne antimicrobial resistance


The Food and Agriculture Organization of the United Nations (FAO) and the Republic of Korea, through its Ministry of Food and Drug Safety (MFDS), today signed a new Framework Arrangement which establishes overarching terms and conditions that will govern the cooperation through voluntary contributions and facilitate future negotiations between MFDS and FAO.

The Arrangement focuses on food safety and standard setting, and contains a Contribution Arrangement which will help to simplify the implementation of individual projects.

The Republic of Korea will provide $10 million to help implement and monitor Codex Alimentarius international food standards, with the goal of containing and reducing foodborne antimicrobial resistance (AMR). AMR not only poses a major threat to human and animal health, but also has serious implications for food safety, food security and the economic wellbeing of millions of farming households.

The first project under the Arrangement will be implemented by the Joint FAO/WHO Centre on CODEX Food Standards and Zoonotic Diseases the FAO Division on Food Systems and Food Safety, and will focus on implementing Codex standards to support containment and reduction of foodborne AMR in six countries: Cambodia, Mongolia, Pakistan, Nepal, Bolivia and Colombia.

Signing on behalf of FAO, Deputy Director-General, Beth Bechdol, praised the Republic of Korea’s continuous interest and effort to increase cooperation with FAO and its deep commitment for the development of international food standards and to the Codex Alimentarius. “The COVID-19 pandemic has shown us how important it is to boost international food safety standards to ensure our food keeps travelling safely across borders, safeguarding food and nutritional security. We must transform our agri-food systems to make them more resilient and inclusive if we are to ensure a better food future for all.”

Since joining FAO as a recipient country in 1949, the Republic of Korea has transformed into a major G-20 economy and a dedicated FAO resource partner. The country is a long-standing Member and strong supporter of the Codex Alimentarius Commission, which sets international and regional standards, guidelines and codes of practice. The broad scope of Codex, which covers areas such as contaminants, nutrition, food hygiene, additives, antimicrobial resistance and pesticide and veterinary drug residues, makes it an essential tool to achieve food security and end hunger.

Jinseok Kim, Vice Minister of the MFDS welcomed the new Arrangement as a way to streamline and enhance the long-lasting cooperation between FAO and the Republic of Korea, and, in the years to come, as a basis for both parties to increase interventions within their joint areas of interest.

“Without global collaboration, we cannot overcome the difficulties due to the pandemic and I believe this is why we are here today: to work together,” Vice Minister Kim affirmed. “It is our responsibility to support other countries, and the most effective way to do this is through FAO, the key player in food safety in the UN.  It is essential to continue to move forward, and as of today Korea would like to play a leading role in world food safety.”

The Republic of Korea currently hosts the Codex ad hoc Intergovernmental Task Force on Antimicrobial Resistance (TFAMR), which is charged with developing science-based guidance on the management of foodborne antimicrobial resistance. The TFAMR is expected to complete its work in 2021.

In addition to hosting the TFAMR and supporting international standard development, the Republic of Korea leads by example in its own efforts to minimize and contain AMR in the food chain, and has expressed a desire to assist other countries in addressing AMR, by supporting the transition from standard-setting to the implementation of Codex guidance, with the collaboration and support of FAO.

Research – Prevalence, Antibiogram and Genetic Characterization of Listeria monocytogenes from Food Products in Egypt


World Health Organization classified Listeria monocytogenes as a major notable foodborne pathogen associated with high mortality and hospitalization. The study reports the prevalence, antibiogram, virulence determination and genetic characterization of L. monocytogenes from different food products. A total of 250 food samples, fifty samples each from raw milk, ice cream, minced meat, fish fillet and sausage were collected from the Menoufiya governorate in Egypt. L. monocytogenes was detected in 17 (6.8%) of the tested food samples including minced meat (14%), fish fillet (8%), sausage (6%) and raw milk (6%). The antimicrobial susceptibility assay of 17 L. monocytogenes isolates against seventeen antibiotics belonging to eight antibiotics classes revealed a high susceptibility to norfloxacin (82.3%), amoxicillin-clavulanic acid (76.4%), cefotaxime (70.5%), erythromycin (64.6%), amoxicillin (64.6%), gentamicin (58.7%) and vancomycin (58.7%). While, high resistance was observed against oxytetracycline (76.4%), trimethoprim-sulfamethoxazole (76.4%), chloramphenicol (70.5%), doxycycline (64.6%), levofloxacin (41.2%) and azithromycin (41.2%). Of note, all L. monocytogenes isolates were multidrug-resistant. The multiplex PCR successfully amplified L. monocytogenes in all tested isolates. Screening of the five virulence-related genes revealed the hlyA and iap as the most prevalent genes followed by actA gene, however, the inlA and prfA genes were not detected in any of the studied isolates. The partial 16S rRNA gene sequencing of three L. monocytogenes isolates showed a high nucleotide similarity (99.1–99.8%) between the study isolates and various global clones, and phylogenetic analysis clustered these L. monocytogenes strains with other Listeria species including L. welshimeriL. seeligeri and L. innocua. This study demonstrates the impact of L. monocytogenes as a major contaminant of various food products and suggests more attention to the awareness and hygienic measures in the food industry. View Full-Text

Research – Resistance levels still high in bacteria causing foodborne infections


A sizeable proportion of Salmonella and Campylobacter bacteria is still resistant to antibiotics commonly used in humans and animals, as in previous years, says a report released today by the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA).

In humans, high proportions of resistance to ciprofloxacin, an antibiotic commonly used to treat several types of infections, were reported in a specific Salmonella type known as S. Kentucky (82.1%). In recent years, S. Enteritidis resistant to nalidixic acid and/or ciprofloxacin has been increasingly reported in several countries. The increasing occurrence of fluoroquinolone and/or quinolone resistance in these types of Salmonella probably reflects the spread of particularly resistant strains.

In Campylobacter, resistance to ciprofloxacin is now so common in most countries that this antimicrobial has limited use in treatment of Campylobacter infections in humans.

However, the report also includes some positive findings. Over the period 2015-2019, a decline in resistance to ampicillin and tetracyclines has been observed in Salmonella isolates from humans in eight and eleven Member States respectively.

A decreasing trend has also been observed in the prevalence of extended-spectrum β-lactamase (ESBL)- producing E. coli in samples from food producing animals from 13 Member States between 2015 and 2019. This is an important finding as particular strains of ESBL-producing E. coli are responsible for serious infections in humans.

Combined resistance to two critically important antimicrobials – fluoroquinolones and third generation cephalosporines in Salmonella and fluoroquinolones and macrolides in Campylobacter – remains low. These critically important antimicrobials are commonly used to treat serious infections from Salmonella and Campylobacter in humans.

The rate of E. coli bacteria in samples from food producing animals that respond to all antimicrobials tested also increased. This was observed in nine Member States over the period 2014-2019.

The report was based on antimicrobial resistance monitoring data collected by Member States as part of their EU regulatory obligations and jointly analysed by EFSA and ECDC with the assistance of external contractors.

Research – Microbial Safety of Smoothie Drinks from Fresh Bars Collected in Slovakia


Among the many consumers in Slovakia, smoothies are nowadays gaining popularity. Smoothie drinks are prepared from raw fruits and vegetables. Therefore, their microbiological safety depends on hygiene standards. The aim of this work was to monitor and quantify selected sensitive and antibiotic-resistant microorganisms present in collected smoothies. Twenty analyzed smoothie samples were collected from six food service establishments (fresh bars) in the capital city of Slovakia, Bratislava. Antibiotic-resistant bacteria were found in at least one of each fresh bar. Antibiotic-resistant coliform bacteria prevailed, especially in green smoothies or juices containing more vegetable ingredients. Resistance to ampicillin, ciprofloxacin, tetracycline, chloramphenicol, and gentamicin was observed in the case of coliform bacteria. More than half of the smoothie drink samples did not contain resistant enterococci. On the other hand, vancomycin-resistant enterococci were detected in 20% of samples. The most frequently isolated antibiotic-resistant strains belonged to the Enterobacter spp. or Klebsiella spp. genus. In the last part of the work, the pretreatment effect of smoothie components on the selected microorganisms’ counts in the final product was investigated. Washing ingredients with an aqueous solution of a biocide agent containing silver and hydrogen peroxide proved to be the most effective way to decrease bacterial counts. View Full-Text

Research – Garcinia mangostana extract inhibits the attachment of chicken isolates of Listeria monocytogenes to cultured colorectal cells potentially due to a high proanthocyanidin content

Wiley Online

Listeria monocytogenes are pathogenic microorganisms and of particular concern in the poultry industry. They are frequently isolated from raw chicken products due to their ability to attach to a wide variety of food and food‐contact surfaces. The application of synthetic antimicrobial agents is often limited by potential emergence of antimicrobial resistance and regulations associated to organic poultry products. Development of natural antimicrobial agents controlling Listeria monocytogenes contamination and pathogenesis represent an alternative approach. This study screened a range of plant extracts (including those from cranberry, mangosteen, persimmon, and roselle) for their ability to affect five Listeria monocytogenes strains with respect to their bacterial surface hydrophobicity, auto‐aggregation, and attachment to cultured human colorectal cells. Results show that mangosteen extracts showed significant inhibitory effects on the attachment of Listeria monocytogenes to the cell line, potentially due to a high level of proanthocyanidin content. In addition, the plant extracts influenced bacterial auto‐aggregation (increase in most of the cases) by increasing bacterial surface hydrophobicity. These results may support future development of alternative antimicrobial agents controlling the contamination and pathogenesis of Listeria monocytogenes.

Research – Bacteria Broadly-Resistant to Last Resort Antibiotics Detected in Commercial Chicken Farms


Resistance to last resort antibiotics in bacteria is an emerging threat to human and animal health. It is important to identify the source of these antimicrobial resistant (AMR) bacteria that are resistant to clinically important antibiotics and evaluate their potential transfer among bacteria. The objectives of this study were to (i) detect bacteria resistant to colistin, carbapenems, and β-lactams in commercial poultry farms, (ii) characterize phylogenetic and virulence markers of E. coli isolates to potentiate virulence risk, and (iii) assess potential transfer of AMR from these isolates via conjugation. Ceca contents from laying hens from conventional cage (CC) and cage-free (CF) farms at three maturity stages were randomly sampled and screened for extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, carbapenem-resistant Acinetobacter (CRA), and colistin resistant Escherichia coli (CRE) using CHROMagar™ selective media. We found a wide-spread abundance of CRE in both CC and CF hens across all three maturity stages. Extraintestinal pathogenic Escherichia coli phylogenetic groups B2 and D, as well as plasmidic virulence markers iss and iutA, were widely associated with AMR E. coli isolates. ESBL-producing Enterobacteriaceae were uniquely detected in the early lay period of both CC and CF, while multidrug resistant (MDR) Acinetobacter were found in peak and late lay periods of both CC and CF. CRA was detected in CF hens only. blaCMY was detected in ESBL-producing E. coli in CC and CF and MDR Acinetobacter spp. in CC. Finally, the blaCMY was shown to be transferrable via an IncK/B plasmid in CC. The presence of MDR to the last-resort antibiotics that are transferable between bacteria in food-producing animals is alarming and warrants studies to develop strategies for their mitigation in the environment. View Full-Text

Research – Prevalence, Concentration, and Antimicrobial Resistance Profiles of Salmonella Isolated from Florida Poultry Litter

Journal of Food Protection


For over a decade, Salmonella contamination has increasingly led to outbreaks of foodborne illness associated with fresh produce. The use of untreated animal manures, or biological soil amendments of animal origin, to amend agricultural soils holds a risk of contamination from foodborne pathogens, such as Salmonella. This study was conducted to determine the prevalence, concentration, serotypes, and antimicrobial resistance profiles of Salmonella in poultry litter from Florida farms. Litter pH, total Kjeldahl nitrogen, total ammonia nitrogen, total phosphorus (P2O5), total potassium (K2O), moisture content, total solids, total ash, organic matter, and aerobic plate count (APC) were also measured. Litter samples (n = 54) were collected from 18 broiler farms across three seasons (spring, summer, and winter). Salmonella concentrations were enumerated using a most-probable-number (MPN) method, and antimicrobial susceptibility testing was performed. The prevalence of Salmonella in litter samples was 61.1%, with a geometric mean of 0.21 ± 20.7 MPN/g. Across all seasons, Salmonella concentrations were not influenced by the chemical, physical, or microbial properties measured. Recovered Salmonella isolates (n = 290) were grouped into serogroups O:4 (43.1%), O:7 (26.9%), O:8 (11.0%), O:1,3,10,19 (7.9%), and O:9,46 (7.2%). Serotyping Salmonella isolates (n = 47) resulted in 12 serotypes, with the most common being Typhimurium (27.7%), Kentucky (17.0%), Enteritidis (14.9%), and Mbandaka (14.9%). Antimicrobial resistance to tetracycline (29.8%), sulfisoxazole (23.4%), and streptomycin (14.9%) was observed. No isolates were resistant to more than two antimicrobial agents. This study provides valuable information for future risk assessments for the use of poultry litter as an untreated biological soil amendment of animal origin.

  • Prevalence and concentration of Salmonella in Florida poultry litter were examined.
  • Serovars Typhimurium, Kentucky, Enteritidis, and Mbandaka were most common.
  • Antimicrobial resistance to tetracycline, sulfisoxazole, and streptomycin was seen.
  • Multidrug-resistant Salmonella isolates were not observed.

Research – Prevalence of Antibiotic-Resistant Escherichia coli Isolates from Local and Imported Retail Chicken Carcasses

Journal of Food Protection


The spread of antibiotic resistance among bacterial strains has been associated with consumption of food contaminated with both pathogenic and nonpathogenic bacteria. The objective of this study was to determine the prevalence of antibiotic resistant Escherichia coli isolates in local and imported retail raw chicken meat in Qatar. A total of 270 locally produced (chilled) and imported (chilled or frozen) whole chicken carcasses were obtained from three Hypermarket stores in Qatar. The 216 E. coli isolates recovered from the chicken samples were subjected to antibiotic susceptibility testing with the disk diffusion method. Extended-spectrum β-lactamase (ESBL) production was evaluated with the double disk synergy test. Isolates harboring colistin resistance were identified with a multiplex PCR assay and DNA sequencing. Nearly 89% (192) of the 216 isolates were resistant to at least one of the 18 antibiotics tested. Isolates from local and imported chicken carcasses had relatively higher resistance to sulfamethoxazole (62% of isolates), tetracycline (59.7%), ampicillin and trimethoprim (52.3% each), ciprofloxacin (47.7%), cephalothin (45.4%), and colistin (31.9%). Less resistance was found to amoxicillin–clavulanic acid (6%), ceftriaxone (5.1%), nitrofurantoin (4.2%), piperacillin-tazobactam (4.2%), cefepime (2.3%), meropenem (1.4%), ertapenem (0.9%), and amikacin (0.9%). Nine isolates (4.2%) were ESBL producers, and 137 (63.4%) were multidrug resistant. The percentages of multidrug-resistant, ESBL-producing, and colistin resistant isolates were significantly higher among isolates from local chilled than from imported chilled and frozen chicken samples. Our findings indicate the high prevalence of antibiotic-resistant E. coli in chicken meat sold at retail in Qatar.

  • A high prevalence of antibiotic resistant E. coli was found in retail chicken in Qatar.
  • Multidrug resistance was observed in 63.4% of the E. coli isolates.
  • Colistin resistance was observed in 31.9% of the E. coli isolates.
  • Contamination of chicken meat with antibiotic-resistant E. coli is a public health concern.

Research – Antibiotic Resistance and Biofilm-Forming Ability in Enterococcal Isolates from Red Meat and Poultry Preparations


kswfoodworld biofilm

This study investigated the resistance to antibiotics and the capacity to form a biofilm of 200 isolates of enterococci isolated from raw preparations of beef (51 strains), pork (47), chicken (50), and turkey (52) acquired in north-western Spain. Fifteen antimicrobials of clinical importance were tested by the disc diffusion method. The average number of resistances per strain was 4.48 ± 1.59. If resistant strains were taken together with those showing reduced susceptibility, the total number of resistances per strain was 6.97 ± 2.02. Two isolates (1.0% of strains) were resistant to a single antibiotic, twenty-two isolates (11.0%) presented resistance to two, one strain (0.5%) was resistant to three, and 175 isolates (87.5%) showed a multiple drug-resistant phenotype (MDR; defined as no susceptibility to at least one agent from each of three or more antimicrobial categories). The prevalence of resistance varied between 0.5% (gentamicin) and 100% (kanamycin). All strains produced biofilm on polystyrene microwell plates, determined using crystal violet assay. Isolates were classified as having a weak (51 strains; average optical density at 580 nanometers -OD580– = 0.206 ± 0.033), moderate (78 strains; average OD580 = 0.374 ± 0.068), or strong (71 strains; average OD580 = 1.167 ± 0.621) ability to produce biofilm (p < 0.05). Isolates from beef preparations produced the most substantial (p < 0.05) biofilms. The results of this study indicate that meat and poultry preparations are major reservoirs of antibiotic-resistant enterococcal strains capable of forming a biofilm. In order for food-borne infections to be prevented, the importance of careful handling of these foodstuffs during preparation, avoiding cross-contamination, and ensuring thorough cooking, is stressed.

Research – Variation of antibiotic resistance in Salmonella Enteritidis, Escherichia coli O157 :H7 , and Listeria monocytogenes after exposure to acid, salt, and cold stress

Wiley Online


Bacteria with antibiotic‐resistant could seriously threaten to human health, increasing the treatment cost for infections and negatively affecting treatment outcomes. Stress adaptation is one possible mechanism for the acquisition or enhancement of antibiotic resistance in bacteria as a result of cross‐protection. In this study, the effects of acid, salt, and cold stress on the antibiotic resistance of Salmonella Enteritidis, Listeria monocytogenes , and Escherichia coli O157:H7 were investigated using the disc diffusion method. For S. Enteritidis, acidic growth conditions increased resistance to ciprofloxacin and erythromycin ( < .05), and addition of 4% NaCl to growth media decreased resistance to chloramphenicol ( < .05). Irrespective of pH and the NaCl concentration of the growth medium, refrigerated E. coli O157:H7 showed increased resistance to amoxycillin, ciprofloxacin, gentamicin, streptomycin, and erythromycin ( < .05). Acid‐adapted L. monocytogenes showed decreased the resistance to amoxycillin, ampicillin, chloramphenicol, ciprofloxacin, erythromycin, gentamicin, streptomycin, and tetracycline ( < .05). In conclusion, prolonged exposure of foodborne pathogens to acid, salt, and cold stress alters their antibiotic resistance. However, the effect of acid, salt, and cold stress on bacterial antibiotic resistance depend on both the bacterial species and the specific antibiotic. Therefore, multiple factors need to be considered for a foodborne antimicrobial resistant risk assessment.