Category Archives: Antimicrobials

Research – Predictive Mapping of Antimicrobial Resistance for Escherichia coli, Salmonella, and Campylobacter in Food-Producing Animals, Europe, 2000–2021

Posted on December 30, 2023 by | Leave a comment

cdc

Abstract

In Europe, systematic national surveillance of antimicrobial resistance (AMR) in food-producing animals has been conducted for decades; however, geographic distribution within countries remains unknown. To determine distribution within Europe, we combined 33,802 country-level AMR prevalence estimates with 2,849 local AMR prevalence estimates from 209 point prevalence surveys across 31 countries. We produced geospatial models of AMR prevalence in Escherichia coli, nontyphoidal Salmonella, and Campylobacter for cattle, pigs, and poultry. We summarized AMR trends by using the proportion of tested antimicrobial compounds with resistance >50% and generated predictive maps at 10 × 10 km resolution that disaggregated AMR prevalence. For E. coli, predicted prevalence rates were highest in southern Romania and southern/eastern Italy; for Salmonella, southern Hungary and central Poland; and for Campylobacter, throughout Spain. Our findings suggest that AMR distribution is heterogeneous within countries and that surveillance data from below the country level could help with prioritizing resources to reduce AMR.

Leave a comment

Posted in Antibacterial, Antibiotic Resistance, antifungal, antimicrobial resistance, Antimicrobials, Campylobacter, E.coli, Food Microbiology Research, Multi Drug Resistant, Research, Salmonella

Research -The Primary Mode of Action of Lippia graveolens Essential Oil on Salmonella enterica subsp. Enterica Serovar Typhimurium

Posted on December 10, 2023 by | Leave a comment

MDPI

Abstract

Essential oils are known to exhibit diverse antimicrobial properties, showing their value as a natural resource. Our work aimed to investigate the primary mode of action of Cuban Lippia graveolens (Kunth) essential oil (EO) against Salmonella enterica subsp. enterica serovar Typhimurium (S. enterica ser. Typhimurium). We assessed cell integrity through various assays, including time-kill bacteriolysis, loss of cell material with absorption at 260 and 280 nm, total protein leakage, and transmission electron microscopy (TEM). The impact of L. graveolens EO on membrane depolarization was monitored and levels of intracellular and extracellular ATP were measured by fluorescence intensity. The minimum inhibitory and bactericidal concentrations (MIC and MBC) of L. graveolens EO were 0.4 and 0.8 mg/mL, respectively. This EO exhibited notable bactericidal effects on treated cells within 15 min without lysis or leakage of cellular material. TEM showed distinct alterations in cellular ultrastructure, including membrane shrinkage and cytoplasmic content redistribution. We also observed disruption of the membrane potential along with reduced intracellular and extracellular ATP concentrations. These findings show that L. graveolens EO induces the death of S. enterica ser. Typhimurium, important information that can be used to combat this foodborne disease-causing agent.

Leave a comment

Posted in antimicrobial resistance, Antimicrobials, Food Microbiology Research, Research, Salmonella

Research – Sweet and sour synergy: exploring the antibacterial and antibiofilm activity of acetic acid and vinegar combined with medical-grade honeys

Posted on December 5, 2023 by | Leave a comment

Microbiology Society

ABSTRACT

, a combination of honey and vinegar, has been used as a remedy for wounds and infections in historical and traditional medical settings. While honey is now clinically used to treat infected wounds, this use of a complex, raw natural product (NP) mixture is unusual in modern western medicine. Research into the antimicrobial activity of NPs more usually focuses on finding a single active compound. The acetic acid in vinegar is known to have antibacterial activity at low concentrations and is in clinical use to treat burn wound infections. Here, we investigated the potential for synergistic activity of different compounds present in a complex ingredient used in historical medicine (vinegar) and in an ingredient mixture (). We conducted a systematic review to investigate published evidence for antimicrobial effects of vinegars against human pathogenic bacteria and fungi. No published studies have explicitly compared the activity of vinegar with that of a comparable concentration of acetic acid. We then characterized selected vinegars by HPLC and assessed the antibacterial and antibiofilm activity of the vinegars and acetic acid, alone and in combination with medical-grade honeys, against and . We found that some vinegars have antibacterial activity that exceeds that predicted by their acetic acid content alone, but that this depends on the bacterial species being investigated and the growth conditions (media type, planktonic vs. biofilm). Pomegranate vinegars may be particularly interesting candidates for further study. We also conclude that there is potential for acetic acid, and some vinegars, to show synergistic antibiofilm activity with manuka honey.

Leave a comment

Posted in Antibiotic Resistance, antimicrobial resistance, Antimicrobials, Biofilm, Food Microbiology Research, Pseudomonas aeruginosa, Research, Staphylococcal Toxin

Research – Chemical Composition and Antimicrobial Activity against the Listeria monocytogenes of Essential Oils from Seven Salvia Species

Posted on December 4, 2023 by | Leave a comment

MDPI

Abstract

In recent years, essential oils (EOs) have received interest due to their antibacterial properties. Accordingly, the present study aimed to investigate the effectiveness of the EOs obtained from seven species of Salvia on three strains of Listeria monocytogenes (two serotyped wild strains and one ATCC strain), a bacterium able to contaminate food products and cause foodborne disease in humans. The Salvia species analysed in the present study were cultivated at the Botanic Garden and Museum of the University of Pisa, and their air-dried aerial parts were subjected to hydrodistillation using a Clevenger apparatus. The obtained EOs were analysed via gas chromatography coupled with mass spectrometry for the evaluation of their chemical composition, and they were tested for their inhibitory and bactericidal activities by means of MIC and MBC. The tested Eos showed promising results, and the best outcomes were reached by S. chamaedryoides EO, showing an MIC of 1:256 and an MBC of 1:64. The predominant compounds of this EO were the sesquiterpenes caryophyllene oxide and β-caryophyllene, together with the monoterpenes bornyl acetate and borneol. These results suggest that these EOs may possibly be used in the food industry as preservatives of natural origins.

Leave a comment

Posted in Antibacterial, Antimicrobials, essential oils, Food Microbiology Research, Listeria, Listeria monocytogenes, Research

New Zealand Research – Superbugs: how you can help fight back

Posted on November 19, 2023 by | Leave a comment

MPI

New Zealand Food Safety is fighting back against superbugs – antimicrobial resistance (AMR) – and we need your help.

“The World Health Organization has identified AMR as one of the top 10 global health threats facing humanity,” says New Zealand Food Safety deputy director-general Vincent Arbuckle.

“World Antimicrobial Awareness Week, which begins tomorrow, recognises that this serious issue will need a global effort to manage. This year’s theme is ‘preventing antimicrobial resistance together’.”

AMR occurs when microbes, or germs, develop resistance to medicines, such as antibiotics. Antimicrobial medicines are critical to human, animal, and plant health, as well as the environment, but they lose effectiveness over time if they are not properly handled and disposed of.

“Antibiotic medicines are essential to the health of humans, animals, and plants. If they are not used properly, diseases can develop resistance, which makes the medicine less effective,” says Mr Arbuckle.

“Everyone has a role to play to ensure the appropriate use and disposal of antibiotics in their care to prevent the spread of AMR in humans, animals, plants, and the environment.

“New Zealand Food Safety works to reduce AMR risks in domestic animals, livestock and plants with a dedicated team that works with the New Zealand veterinary and primary industry sectors to promote careful use of antibiotics and encourage infection prevention strategies such as good hygiene and vaccination, and undertake surveillance for resistance in bacteria collected from animal samples.”

Here’s what pet owners and livestock farmers can do to help reduce the risk:

  • Take measures to keep animals healthy, such as keeping up them up to date with vaccinations and using good hygiene and biosecurity.
  • If antibiotics are needed, closely follow the instructions outlined by your veterinarian. Make sure you give the correct dose, at the right time of day, and for the prescribed duration.
  • Wash your hands after dosing and handling animals.
  • Make sure your animal completes the prescribed course. If for some reason you are unable to complete the course, let your veterinarian know so they can help you.
  • Never keep antibiotics for future use because each infection and animal need unique treatment.
  • Dispose of the empty containers appropriately to help keep the environment safe.

“In further good news, our 2022 Antibiotic agricultural compound sales analysis shows quantities of antibiotics used in animals have been declining for the last 5 years, with a 23% reduction. However we need to continue our efforts to preserve the effectiveness of lifesaving medicines,” says Mr Arbuckle.

Media release: Sales of antibiotics used in animals and plants down by nearly a quarter

New Zealand Food Safety takes a One Health approach to AMR, working closely with the Ministry of Health including on the joint New Zealand antimicrobial resistance action plan – with an updated plan due for publication in 2024.

New Zealand antimicrobial resistance action plan [PDF, 836KB] 

Find out more

For further information and general enquiries, call MPI on 0800 00 83 33 or email info@mpi.govt.nz

Leave a comment

Posted in Antibiotic Resistance, antimicrobial resistance, Antimicrobials, Food Microbiology Research, Research, Superbugs

Research – Prevalence of Multidrug-Resistant Pseudomonas aeruginosa Isolated from Dairy Cattle, Milk, Environment, and Workers’ Hands

Posted on November 15, 2023 by | Leave a comment

MDPI

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen causing severe infection in animals and humans. This study aimed to determine the ecological distribution and prevalence of multidrug-resistant (MDR) P. aeruginosa isolated from dairy cattle, the environment, and workers’ hand swabs. Samples (n = 440) were collected from farms and households (n = 3, each). Rectal swabs, udder skin swabs, milk, workers’ hand swabs, feed, water, water sources, and beddings were collected. Samples were subjected to the bacterial identification of P. aeruginosa via 16S rRNA. Antimicrobial resistance (AMR) was detected either phenotypically using an antibiotic susceptibility test or genotypically with AMR resistance genes (ARGs) such as drfA, sul1, and ermB. P. aeruginosa was detected on dairy farms and households (10.3–57.5%, respectively), with an average of 23.2%. The resistance of dairy farm strains was observed against sulfamethoxazole, imipenem, cefepime, piperacillin–tazobactam, and gentamycin (100%, 72.7%, 72.7%, 68.8%, and 63.3%, respectively). Meanwhile, the resistance of household strains was observed against sulfamethoxazole, imipenem, amoxicillin, gentamicin, cefepime, and erythromycin by 91.3%, 82.6%, 75.4%, 75.4%, 68.1%, and 63.8%, respectively. The susceptibility of farm strains was detected against norfloxacin, ciprofloxacin, and levofloxacin (90.9%, 84.8%, and 72.7%, respectively). Meanwhile, the susceptibility of household strains was detected against ciprofloxacin, amikacin, and norfloxacin (100%, 84.1%, and 72.5%, respectively). About 81.4% of P. aeruginosa strains were MDR. ARGs (drfA, sul1, and ermB) were detected in farm strains (48.5%, 72.7%, and 24.4%, respectively) and household strains (50.7%, 72.5%, and 47.8%, respectively). Almost all P. aeruginosa had MAR over 0.2, indicating repeated application of antibiotics. P. aeruginosa prevalence was fivefold higher in households than on farms. MDR strains were higher amongst household strains than farm strains.

Leave a comment

Posted in Antibiotic Resistance, antimicrobial resistance, Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Microbiological Risk Assessment, Pseudomonas, Pseudomonas aeruginosa, Research

Research – Survival of Foodborne Pathogens in Low and Nonalcoholic Craft Beer

Posted on November 4, 2023 by | Leave a comment

Science Direct

Abstract

Breweries and beverage companies have recently been interested in creating innovative beer varieties that deviate from traditional beer styles, with either low-alcohol content <2.5% alcohol by volume (ABV) or the absence of alcohol altogether (<0.5% ABV). Traditional beers (up to 10% ABV) contain numerous intrinsic and extrinsic factors preventing pathogens from proliferation or propagation. Physiochemical properties such as a low pH, presence of ethanol and hop acids, limited oxygen, and specific processing techniques, including wort boiling, pasteurization, filtration, cold storage, and handling, all contribute to microbial stability and safety. The potential change or absence in one or more of these antimicrobial hurdles can render the final product susceptible to pathogen survival and growth. In this study, the effect of pH, storage temperature, and ethanol concentration on the growth or die-off of foodborne pathogens in low and nonalcoholic beers was evaluated. pH and ethanol concentrations were adjusted from their initial values of 3.65 and <0.50% ABV to pHs 4.20, 4.60, and 4.80; and 3.20 ABV, respectively. The samples were inoculated with individual five-strain cocktails of E. coli O157:H7, S. enterica, and L. monocytogenes, then stored at two different temperatures (4 and 14°C) for 63 days. Microbial enumeration was performed using selective agar with incubation at 35°C. Results showed that nonalcoholic beers allowed for pathogen growth and survival, as opposed to the low-alcoholic ones. E. coli O157:H7 and S. enterica grew approximately 2.00 log  at 14°C, but no growth was observed at 4°C. L. monocytogenes was more susceptible and fell at, or below, the detection limit rapidly in all the conditions tested. The results show that storage temperature is critical in preventing the growth of pathogens. pH did not appear to have a significant effect on the survival of pathogens (p < 0.05). This challenge study demonstrates the need for beverage manufacturers to prioritize and maintain food safety plans along with practices specific to low- and nonalcoholic beer manufacturers.

Leave a comment

Posted in antimicrobial resistance, Antimicrobials, E.coli O157, E.coli O157:H7, Food Microbiology Research, Food Technology, Listeria, Listeria monocytogenes, Research, Salmonella, Technology

Research – Resistant Salmonella infections linked to worse outcomes

Posted on October 19, 2023 by | Leave a comment

CIDRAP

kswfoodworld Salmonella

Infections caused by Salmonella with any antibiotic resistance are associated with more severe clinical outcomes, including hospitalization and death, Centers for Disease Control and Prevention (CDC) researchers reported yesterday in Clinical Infectious Diseases.

Using epidemiologic data from the Foodborne Diseases Active Surveillance Network (FoodNet) and antimicrobial resistance data from the National Antimicrobial Resistance Monitoring System (NARMS), researchers from the CDC’s Division of Foodborne, Waterborne, and Environmental Diseases examined outcomes in patients with nontyphoidal Salmonella infections from 2004 through 2018. They compared outcomes for resistant Salmonella infections with those caused by non-resistant Salmonella before and after adjusting for age, state, race/ethnicity, international travel, outbreak association, and isolate serotype or source.

Leave a comment

Posted in Animal Feed, Antibacterial, Antibiotic Resistance, antimicrobial resistance, Antimicrobials, CDC, Food Microbiology Research, Research, Salmonella

Research – Natural Antimicrobials: A Reservoir to Contrast Listeria monocytogenes

Posted on October 19, 2023 by | Leave a comment

MDPI

Abstract

Natural environments possess a reservoir of compounds exerting antimicrobial activity that are forms of defence for some organisms against others. Recently, they have become more and more attractive in the food sector due to the increasing demand for natural compounds that have the capacity to protect food from pathogenic microorganisms. Among foodborne pathogens, Listeria monocytogenes can contaminate food during production, distribution, or storage, and its presence is especially detected in fresh, raw food and ready-to-eat products. The interest in this microorganism is related to listeriosis, a severe disease with a high mortality rate that can occur after its ingestion. Starting from this premise, the present review aims to investigate plant extract and fermented plant matrices, as well as the compounds or mixtures of compounds produced during microbial fermentation processes that have anti-listeria activity.

Leave a comment

Posted in antimicrobial resistance, Antimicrobials, Food Microbiology Research, Listeria, Listeria monocytogenes, Research

Research – Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance

Posted on October 8, 2023 by | Leave a comment

MDPI

Abstract

Antimicrobial resistance is now commonly observed in bacterial isolates from multiple settings, compromising the efficacy of current antimicrobial agents. Therefore, there is an urgent requirement for efficacious novel antimicrobials to be used as therapeutics, prophylactically or as preservatives. One promising source of novel antimicrobial chemicals is phytochemicals, which are secondary metabolites produced by plants for numerous purposes, including antimicrobial defence. In this report, we compare the bioactivity of a range of phytochemical compounds, testing their ability to directly inhibit growth or to potentiate other antimicrobials against Salmonella enterica Typhimurium, Pseudomonas aeruginosa, Listeria monocytogenes, and Staphylococcus aureus. We found that nine compounds displayed consistent bioactivity either as direct antimicrobials or as potentiators. Thymol at 0.5 mg/mL showed the greatest antimicrobial effect and significantly reduced the growth of all species, reducing viable cell populations by 66.8%, 43.2%, 29.5%, and 70.2% against S. enterica Typhimurium, S. aureus, P. aeruginosa, and L. monocytogenes, respectively. Selection of mutants with decreased susceptibility to thymol was possible for three of the pathogens, at a calculated rate of 3.77 × 10−8, and characterisation of S. enterica Typhimurium mutants showed a low-level MDR phenotype due to over-expression of the major efflux system AcrAB-TolC. These data show that phytochemicals can have strong antimicrobial activity, but emergence of resistance should be evaluated in any further development.

Leave a comment

Posted in Antibacterial, Antibiotic Resistance, antifungal, antimicrobial resistance, Antimicrobials, Drug Resistance, Food Microbiology Research, Food Pathogen, Pathogen, pathogenic, Research