Category Archives: Antibiotic Resistance

Research – Virulence Potential and Antibiotic Susceptibility of S. aureus Strains Isolated from Food Handlers

MDPI

Staphylococcus spp. are common members of the normal human flora. However, some Staphylococcus species are recognised as human pathogens due to the production of several virulence factors and enterotoxins that are particularly worrisome in food poisoning. Since many of Staphylococcal food poisoning outbreaks are typically associated with cross-contamination, the detection of S. aureus on food handlers was performed. Hand swabs from 167 food handlers were analysed for the presence of S. aureus. More than 11% of the samples were positive for S. aureus. All S. aureus strains were isolated and analysed for the presence of virulence and enterotoxin genes, namely, seasebsecsedsegseitsst-1 and pvl. The same strains were phenotypically characterised in terms of antibiotic susceptibility using the disc diffusion method and antimicrobial agents from 12 different classes. A low prevalence of antibiotic-resistant strains was found, with 55.6% of the strains being sensitive to all of the antimicrobial agents tested. However, a high prevalence of resistance to macrolides was found, with 44.4% of the strains showing resistance to erythromycin. At least one of the virulence or toxin genes was detected in 61.1% of the strains, and seg was the most prevalent toxin gene, being detected in 44.4% of the strains.

Research – Antimicrobial Resistance and Virulence Characterization of Listeria monocytogenes Strains Isolated from Food and Food Processing Environments

MDPI

Listeria monocytogenes is a particularly foodborne pathogen associated with listeriosis, which can be disseminated in food and food processing environments. This study aimed to determine the serotypes and characteristics of virulence factors and antibiotic resistance among 40 L. monocytogenes strains isolated from food (n = 27) purchased in Olsztyn (Warmia and Mazury region, Poland) and food processing environments in Poland (n = 13). Isolates were assigned to serotypes 1/2a, 1/2c, 3a, and 3c using polymerase chain reaction (PCR). The results showed that serotype 1/2a (66.7%) was the most prevalent among strains from food, and serotype 1/2c (53.8%) among strains from the food processing environments. Five different virulence factors (hlyA, prfA, inlB, luxS, sigB) were detected in all isolates from the food processing environments using PCR. The hlyA (100.0%), prfA (100.0%), and inlB (96.3%) were the most prevalent in food strains. Seven (25.9%) of the strains of food and ten (76.9%) strains from the food processing environments showed the ability to form biofilm. The tested isolates were subjected to antibiotic susceptibility testing against 12 antibiotics used in the mitigation of listeriosis, using the disk diffusion method. The most frequent were intermediate resistance and resistance to clindamycin. Twelve (92.3%) strains from the food processing environments, and twenty-three (85.2%) from food were non-susceptible to clindamycin. Generally, antibacterial resistance determinants (LdeaadBaac(3)-IIa(aacC2)apenAmefAlnuAlnuBsulI, sulII) were detected in sixteen (59.0%) strains from food and four (30.8%) from the food processing environments, by PCR. The most frequent were the mefA-lnuA (n = 7; 20.0%) and lnuA (n = 6; 17.1%) genotypes. From this research, we can conclude that virulent and antimicrobial-resistant strains of L. monocytogenes are present in food and the food processing environment in Poland, which may pose a potential health risk to consumers. Monitoring for the control of virulent and antimicrobial-resistant L. monocytogenes strains in the food system can contribute to effective planning and prevention of their spread.

Research – New NARMS report shows rising resistance in Salmonella, Campylobacter

CIDRAP

The findings come from the National Antimicrobial Resistance Monitoring Systems (NARMS) 2019 Integrated Summary, which combines data from the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the US Department of Agriculture (USDA). The report provides a snapshot of resistance patterns found in bacteria isolated from humans, animals, raw meats from retail outlets (chicken, ground turkey, ground beef, and pork chops), and meat and poultry product samples collected at slaughtering facilities.

In addition to Salmonella, which causes an estimated 1.35 million illnesses and 26,500 hospitalizations each year, the NARMS report also includes resistance data on Campylobacter (1.5 million illnesses and 19,500 hospitalizations), Escherichia coli, and Enterococcus. NARMS monitors these bacteria to detect emerging resistance patterns to the antibiotics that are most important to human medicine, multidrug resistance, and specific resistance genes.

Research – Occurrence and Multidrug Resistance of Campylobacter in Chicken Meat from Different Production Systems

MDPI

Campylobacter kswfoodworld

Campylobacter is the leading bacterial cause of diarrheal disease worldwide and poultry remains the primary vehicle of its transmission to humans. Due to the rapid increase in antibiotic resistance among Campylobacter strains, the World Health Organization (WHO) added Campylobacter fluoroquinolone resistance to the WHO list of antibiotic-resistant “priority pathogens”. This study aimed to investigate the occurrence and antibiotic resistance of Campylobacter spp. in meat samples from chickens reared in different production systems: (a) conventional, (b) free-range and (c) backyard farming. Campylobacter spp. was detected in all samples from conventionally reared and free-range broilers and in 72.7% of backyard chicken samples. Levels of contamination were on average 2.7 × 103 colony forming units (CFU)/g, 4.4 × 102 CFU/g and 4.2 × 104 CFU/g in conventionally reared, free-range and backyard chickens, respectively. Campylobacter jejuni and Campylobacter coli were the only species isolated. Distribution of these species does not seem to be affected by the production system. The overall prevalence of Campylobacter isolates exhibiting resistance to at least one antimicrobial was 98.4%. All the C. coli isolates showed resistance to ciprofloxacin and to nalidixic acid, and 79.5 and 97.4% to ampicillin and tetracycline, respectively. In total, 96.2% of C. jejuni isolates displayed a resistant phenotype to ciprofloxacin and to nalidixic acid, and 92.3% to ampicillin and tetracycline. Of the 130 Campylobacter isolates tested, 97.7% were classified as multidrug resistant (MDR).

EU – Multi-country outbreak of monophasic Salmonella Typhimurium sequence type 34 linked to chocolate products – first update

EFSA

Abstract

On 17 February 2022, the United Kingdom (UK) reported a cluster of cases with monophasic Salmonella Typhimurium sequence type 34 infection. As of 18 May 2022, 324 cases had been reported in 12 EU/EEA countries and the UK, including two distinct strains. Most cases are below ten years of age and 41% of all cases have been hospitalised. The two strains are multidrug-resistant and some tested isolates also carry resistance to disinfectants that are based on quaternary ammonium compounds and hydrogen peroxide, but remain susceptible to azithromycin, ciprofloxacin, meropenem, and third generation cephalosporins. Epidemiological investigations suggested specific chocolate products of Brand A, produced by Company A in Processing Plant B in Belgium, as likely vehicles of infection.

Two strains of monophasic Salmonella Typhimurium matching the outbreak strains were identified in the buttermilk line at Plant B between December 2021 and January 2022. The buttermilk was provided by an Italian supplier where Salmonella was not detected. The Italian supplier delivered the buttermilk to other plants of Company A where, based on the available evidence, Salmonella was not detected.

On 8 April 2022, based on official controls, the food safety authority in Belgium decided to withdraw the authorisation for production of the Plant B due to lack of transparency and insufficient guarantees for safe production. Company A globally recalled all products of Brand A produced at Plant B. Public warnings were issued by the competent national authorities in different countries.

This outbreak has evolved rapidly, with children most at risk for severe infection. The closure of Plant B and the global recall of all their products have reduced the risk of exposure. However, eight cases cannot be explained by consumption of chocolate products such as those manufactured at Plant B, suggesting that there may also be other sources of infection.

Research – New NARMS report shows rising resistance in Salmonella, Campylobacter

CIDRAP

The latest data from a national surveillance system that monitors foodborne bacterial pathogens for antimicrobial resistance (AMR) shows some concerning changes in resistance patterns among serotypes of Salmonella.

The findings come from the National Antimicrobial Resistance Monitoring Systems (NARMS) 2019 Integrated Summary, which combines data from the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the US Department of Agriculture (USDA). The report provides a snapshot of resistance patterns found in bacteria isolated from humans, animals, raw meats from retail outlets (chicken, ground turkey, ground beef, and pork chops), and meat and poultry product samples collected at slaughtering facilities.

In addition to Salmonella, which causes an estimated 1.35 million illnesses and 26,500 hospitalizations each year, the NARMS report also includes resistance data on Campylobacter (1.5 million illnesses and 19,500 hospitalizations), Escherichia coli, and Enterococcus. NARMS monitors these bacteria to detect emerging resistance patterns to the antibiotics that are most important to human medicine, multidrug resistance, and specific resistance genes.

Increase in multidrug-resistant Salmonella serotype

Overall, the NARMS report shows that more than three fourths of the Salmonella isolates (78%) from humans were not resistant to any of the antibiotics tested, and that the overall level of resistance in humans remains relatively unchanged since 2018. However, the report also found rising resistance to ciprofloxacin—one of the three antibiotics used to treat severe Salmonella infections.

From 2018 to 2019, Salmonella with decreased susceptibility to ciprofloxacin increased from 9% to 11% in humans, from 18% to 31% in retail chicken, from 20% to 30% in chicken product samples, from 26% to 32% in chicken cecal content samples, and from 0% to 14% in retail pork samples.

The increase in resistance to ciprofloxacin among poultry isolates was primarily due to the increase in Salmonella Infantis, a multidrug-resistant (MDR) serotype that emerged in 2014.

The rise in Salmonella Infantis isolates was also behind an increase in MDR isolates found in retail chicken (from 20% to 32%) and in chicken product samples (22% to 29%). Up to 10 antimicrobial resistance (AMR) genes were found in some of the Salmonella Infantis isolates.

In addition, the NARMS report shows an increase in another MDR Salmonella serotype, I 4,[5],12:i:-, which is linked to pigs and has become an increasing public health concern in Europe and the United States. The percentage of MDR isolates from humans that are of the I 4,[5],12:i:- serotype rose from 7% in 2010 to 26% in 2019, and from 7% to 35% in swine samples.

NARMS data also show rising fluoroquinolone resistance in Campylobacter isolates. In humans, the proportion of ciprofloxacin-resistant Campylobacter isolates rose from 29% in 2018 to 34% in 2019 for Campylobacter jejuni and from 41% to 45% in C coli. Ciprofloxacin-resistant C jejuni isolated from chicken cecal contents (21% in 2018 to 26% in 2019) and chicken retail samples (20% to 22%) also rose.

Analysis of E coli isolates found increases in ceftriaxone resistance in sow cecal samples (3% in 2018 to 7% in 2019) and in retail pork (4% to 7%). Whole-genome sequencing of Salmonella and E coli from animals, animal products, and retail meats found that none harbored any of the MCR-1 through MCR-8 colistin-resistance genes.

Research – Salmonella and Campylobacter continue to show high levels of antibiotic resistance

EFSA

Antibiotic resistance in Salmonella and Campylobacter bacteria is still high, says a report released today by the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA).

Campylobacteriosis was the most reported zoonosis in the EU in 2020 and the most frequently reported cause of foodborne illness. Campylobacter bacteria from humans and poultry continues to show very high resistance to ciprofloxacin, a fluoroquinolone antibiotic, that is commonly used to treat some types of bacterial human infection.

Increasing trends of resistance against the fluoroquinolone class of antibiotics has been observed in humans and broilers for Campylobacter jejuni. In Salmonella Enteritidis, the most common type of Salmonella in humans, increasing trends of resistance to the quinolone/fluoroquinolone class of antibiotics were observed. In animals, resistance to these antibiotics in Campylobacter jejuni and Salmonella Enteritidis were generally moderate to high.

However, despite the increasing trends of resistance against certain antibiotics, simultaneous resistance to two critically important antibiotics – remains low for E. coliSalmonella and Campylobacter in bacteria from both humans and food-producing animals.

A decline in resistance to tetracyclines and ampicillin in Salmonella from humans was observed in nine and ten countries, respectively, over the period 2016-2020, and this was particularly evident in Salmonella Typhimurium. Despite the decline, resistance to these antibiotics still remains high in bacteria from both humans and animals.

Furthermore, in more than half of the European Union countries, a statistically significant decreasing trend in the prevalence of extended-spectrum β-lactamase (ESBL)-producing E. coli was observed in food-producing animals. This is an important finding as particular strains of ESBL-producing E. coli are responsible for serious infections in humans.

Carbapenem resistance remains extremely rare in E. coli and Salmonella from food-producing animals. Carbapenems are a class of last resort antibiotics and any findings showing resistance to these in zoonotic bacteria are concerning.

Although findings and trends are consistent with data reported in previous years, the COVID-19 pandemic had an impact on the amount of data reported, particularly with regards to public health.

An interactive data visualisation tool shows resistance levels in humans, animals and food, country-by-country in 2019 and 2020.

Additionally, the human food and waterborne antibiotic resistance data is published in ECDC’s Surveillance Atlas of Infectious Diseases (under the diseases campylobacteriosis, salmonellosis and shigellosis, respectively).

France – Report on surveillance of Campylobacter infections in France in 2020.

Sante Publique

Key points

In 2020, surveillance of Campylobacter infections confirmed the epidemiological and biological trends already observed in recent years: 

  • a predominance of the species C. jejuni ;
  • higher number of cases and incidence in children;
  • a predominance of infections in men, except in people aged 30 to 39;
  • a seasonal peak during the summer period;
  • high resistance to fluoroquinolones and tetracyclines, which has remained stable in recent years;
  • no notable increase in the resistance rates of the six antibiotics tested routinely;
  • the consumption of poultry as the first food (incriminated or suspected) source of contamination in episodes of collective food poisoning.

The number of Campylobacter strains listed by the CNR has been increasing since 2013, the year in which the network’s laboratories introduced online data entry. This increase could be a reflection of an increase in Campylobacter infections in France. However, this increase in the number of strains must be considered within the framework of the specificities of the surveillance system. Several factors, such as an increase in the activity of the network’s laboratories or prescriptions for stool cultures, could cause an increase in the number of isolations and notifications over time. The implementation of multiplex PCR in many laboratories has also facilitated the detection of Campylobacter sp in stool samples.

The health context linked to the COVID-19 pandemic does not seem to have had an impact on the surveillance data. A decrease in the number of strains compared to previous years was observed only in March-April 2020, corresponding to the period of the first confinement. This reduction seems to reflect less recourse to care (medical consultation, biological analyses) during this period, but could also indicate a reduction in the incidence linked to health restrictions.

Research – Multidrug resistance of Escherichia coli in fish supply chain: A preliminary investigation

Wiley Online

Abstract

Ninety-five Escherichia coli isolates recovered from different supply points of freshwater fish namely fish pond (W1, n = 16), wholesale fish market (W2, n = 14), retail fish market (R1, n = 29), street fish vending unit (R2, n = 30), and modern fish vending unit (R3, n = 6) were investigated for antimicrobial-resistant profile and prevalence of antibiotic-resistant genes. Overall, multidrug-resistant (MDR) E. coli in the fish supply chain was 21% with higher MDR incidence in the downstream fish supply points. MDR was relatively higher in the tertiary fish supply points viz., retail fish market (45%), street fish vending unit (30%), and modern fish vending unit (15%) compared to the secondary fish supply point, that is, wholesale fish market (5%) and primary fish supply point, that is, fish pond (5%). All the ampicillin-resistant isolates carried ampC gene, whereas only 21% of the β-lactam resistant isolates carried blaCTX-M-gp1. The tetracycline resistance determinant, tetA (89%) was predominant in the tetracycline-resistant isolates compared to tetB and tetD (11%). The trimethoprim resistance gene, dfrA and sulfonamide-resistance gene, Sul1 were detected in 9% of the trimethoprim-resistant isolates and 9% of the sulfonamide-resistant isolates, respectively. Enterobacterial repetitive intergeneric consensus-PCR has delineated the MDR isolates from the different fish supply points into three major clusters but all the MDR isolates from the street fish vending point are grouped into a single cluster. The results indicate an increase in the proportion of MDR E. coli and the occurrence of diverse MDR profiles in the downstream points of the fish supply chain that needs to be addressed to avoid fish-food-borne antimicrobial resistance.

Research – UC-Santa Cruz undergraduates win award for system that fights E. coli

Food Safety News

A team of undergraduates at the University of California-Santa Cruz has developed a system called Progenie that’s designed to target and eliminate a toxic gene found in Shiga toxin-producing E. coli.

The team’s method provides an alternative to antibiotics commonly used in agriculture. This new method is designed in part to stop the rise of drug-resistant bacteria.

The team’s project won a gold medal at the International Genetically Engineered Machine (iGEM) Jamboree, an annual competition that brings together student teams from around the world to present synthetic biology projects that aim to address pressing global issues.

At the jamboree, teams are judged on their virtual project posters, wiki pages, and video presentations. Teams are awarded gold medals if they demonstrate excellence across multiple categories.