Category Archives: Antimicrobials

Research – Using TRIS-Buffered Plasma-Activated Water to Reduce Pathogenic Microorganisms on Poultry Carcasses with Evaluation of Physicochemical and Sensory Parameters

Posted on March 11, 2023 by | Leave a comment

MDPI

Abstract

Foodborne diseases are mainly caused by the contamination of meat or meat products with pathogenic microorganisms. In this study, we first investigated the in vitro application of TRIS-buffered plasma-activated water (Tb-PAW) on Campylobacter (C.) jejuni and Escherichia (E.) coli, with a reduction of approx. 4.20 ± 0.68 and 5.12 ± 0.46 log10 CFU/mL. Furthermore, chicken and duck thighs (inoculated with C. jejuni or E. coli) and breasts (with natural microflora) with skin were sprayed with Tb-PAW. Samples were packed under a modified atmosphere and stored at 4 °C for 0, 7, and 14 days. The Tb-PAW could reduce C. jejuni on days 7 and 14 (chicken) and E. coli on day 14 (duck) significantly. In chicken, there were no significant differences in sensory, pH-value, color, and antioxidant activity, but %OxyMb levels decreased, whereas %MetMb and %DeoMb increased. In duck, we observed slight differences in pH-value, color, and myoglobin redox forms for the Tb-PAW, which were not perceived by the sensory test persons. With only slight differences in product quality, its application as a spray treatment may be a useful method to reduce C. jejuni and E. coli on chicken and duck carcasses.

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Posted in Antimicrobials, Campylobacter, Decontamination Microbial, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – The Role of Biofilms in the Pathogenesis of Animal Bacterial Infections

Posted on March 4, 2023 by | Leave a comment

MDPI

Abstract

Biofilms are bacterial aggregates embedded in a self-produced, protective matrix. The biofilm lifestyle offers resilience to external threats such as the immune system, antimicrobials, and other treatments. It is therefore not surprising that biofilms have been observed to be present in a number of bacterial infections. This review describes biofilm-associated bacterial infections in most body systems of husbandry animals, including fish, as well as in sport and companion animals. The biofilms have been observed in the auditory, cardiovascular, central nervous, digestive, integumentary, reproductive, respiratory, urinary, and visual system. A number of potential roles that biofilms can play in disease pathogenesis are also described. Biofilms can induce or regulate local inflammation. For some bacterial species, biofilms appear to facilitate intracellular invasion. Biofilms can also obstruct the healing process by acting as a physical barrier. The long-term protection of bacteria in biofilms can contribute to chronic subclinical infections, Furthermore, a biofilm already present may be used by other pathogens to avoid elimination by the immune system. This review shows the importance of acknowledging the role of biofilms in animal bacterial infections, as this influences both diagnostic procedures and treatment.

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Posted in Antibacterial, Antibiotic Resistance, antifungal, antimicrobial resistance, Antimicrobials, Biofilm, Decontamination Microbial, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – A Systematic Quantitative Determination of the Antimicrobial Efficacy of Grape Seed Extract against Foodborne Bacterial Pathogens

Posted on February 26, 2023 by | Leave a comment

MDPI

Abstract

Concerns regarding the role of antimicrobial resistance (AMR) in disease outbreaks are growing due to the excessive use of antibiotics. Moreover, consumers are demanding food products that are minimally processed and produced in a sustainable way, without the use of chemical preservatives or antibiotics. Grape seed extract (GSE) is isolated from wine industry waste and is an interesting source of natural antimicrobials, especially when aiming to increase sustainable processing. The aim of this study was to obtain a systematic understanding of the microbial inactivation efficacy/potential of GSE against Listeria monocytogenes (Gram-positive), Escherichia coli and Salmonella Typhimurium (Gram-negative) in an in vitro model system. More specifically, for L. monocytogenes, the effects of the initial inoculum concentration, bacterial growth phase and absence of the environmental stress response regulon (SigB) on the GSE microbial inactivation potential were investigated. In general, GSE was found to be highly effective at inactivating L. monocytogenes, with higher inactivation achieved for higher GSE concentrations and lower initial inoculum levels. Generally, stationary phase cells were more resistant/tolerant to GSE as compared to exponential phase cells (for the same inoculum level). Additionally, SigB appears to play an important role in the resistance of L. monocytogenes to GSE. The Gram-negative bacteria under study (E. coli and S. Typhimurium) were less susceptible to GSE as compared to L. monocytogenes. Our findings provide a quantitative and mechanistic understanding of the impact of GSE on the microbial dynamics of foodborne pathogens, assisting in the more systematic design of natural antimicrobial-based strategies for sustainable food safety.

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Posted in Antimicrobials, Decontamination Microbial, escherichia coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, Food Safety Management, Food Safety Regulations, food safety training, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella

Research – Foodborne Pathogen Biofilms: Development, Detection, Control, and Antimicrobial Resistance

Posted on February 26, 2023 by | Leave a comment

MDPI

Bacteria can grow either as planktonic cells or as communities within biofilms. The biofilm growth mode is the dominant lifestyle of most bacterial species and 40–80% of microorganisms are associated with biofilms [1]. Biofilm is a sessile community that is irreversibly attached to a substratum or interface or to other members of the community [2]. It is surrounded by extracellular polymeric substances (EPS) that include extracellular polysaccharides, extracellular DNA, lipids, proteins, and other elements [3]. Biofilm formation is a complex but well-regulated process that can be classified into five distinct stages [4]. In the first stage, planktonic bacteria attach to a surface. Salmonella species, Listeria monocytogenes, Campylobacter jejuni, or Escherichia coli have specific structures on the surface of the bacteria, such as flagella, curli, fimbriae, and pili, which help the bacteria attach [5].
The second stage is the adhesion step, which includes an initial reversible adhesion resulting in loose adhesion and a subsequent irreversible adhesion resulting in more stable adhesion. The third stage is to secrete EPS and form microcolonies. This is followed by biofilm maturation, which produces large amounts of EPS to grow in size and build three-dimensional structures. The final stage is the stage in which the biofilm is dispersed, releasing the planktonic cells and initiating the formation of a new biofilm at another location.
Microbial cells living within biofilms are protected from various environmental stresses such as desiccation, osmotic changes, oxidative stress, metal toxicity, radiation, antibiotics, disinfectants, and the host immune system [6]. Biofilms are much less sensitive to antimicrobial agents than planktonic cells, and several mechanisms contribute to their resistance to antimicrobials [7]. The exopolysaccharide matrix prevents the entry of antimicrobial agents by reducing diffusion and acting as a primary barrier [8]. Most antimicrobial agents kill rapidly dividing cells more effectively, but slow growth of biofilms leads to resistance [9]. Changes in metabolic activity within biofilms, genetic changes of antimicrobial resistant determinants in target cells, extrusion of antimicrobial agents using efflux pumps, and the presence of persistent cells also contribute to antimicrobial resistance [10].

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Posted in antimicrobial resistance, Antimicrobials, Biofilm, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – Evaluation of antibiotic efficacy of Ocimum gratissimum L. essential oil against Staphylococcus aureus and Pseudomonas aeruginosa

Posted on February 20, 2023 by | Leave a comment

Academic Journals

Abstract

Ocimum gratissimum essential oil (EOGT) has been evaluated for its antibacterial efficacy, and its combinational therapy with antibiotics may enhance the therapeutic efficiency against infection-causing bacteria. Herein, we evaluated the chemical composition of EOGT and its antibiotic efficacy against Staphylococcus aureus and Pseudomonas aeruginosa. GC-MS and GC-FID analyzed EOGT. The antibiotic efficacy was determined by the agar diffusion method, microdilution, minimum inhibitory concentration (MIC), and fractional inhibitory concentration index (FICI). Eugenol (74.2%) was the main component of OGT. Using the agar diffusion method, the action of rifampicin, ciprofloxacin, and tetracycline was evaluated against S. aureus, while the action of cefepime and ciprofloxacin was evaluated against P. aeruginosa. FICI showed a reduced MIC of ciprofloxacin and tetracycline associated with EOGT. In the presence of EOGT, MIC of ciprofloxacin reduced from 0.6 to 0.0006 μg/mL and of tetracycline decreased from 0.028 to 0.0018 μg/mL against S. aureus and from 4 to 0.12 μg/mL against P. aeruginosa. EOGT enhanced the antibacterial efficacy of the antibiotics suggesting a synergistic effect, thereby enhancing the efficacy in treating infection against S. aureus and P. aeruginosa.

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Posted in Antimicrobials, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pseudomonas aeruginosa, Staphylococcus aureus

Research – Antimicrobial Effect of Moringa oleifera Leaves Extract on Foodborne Pathogens in Ground Beef

Posted on February 18, 2023 by | Leave a comment

MDPI

Abstract

Consumers nowadays are becoming more aware of the importance of using only meat products containing safe and natural additives. Hence, using natural food additives for extending the shelf life of meat along with delaying microbial growth has become an urgent issue. Given the increasingly popular view of Moringa oleifera leaves as a traditional remedy and also the scarcity of published data concerning its antimicrobial effect against foodborne pathogens in meat and meat products, we designed the present study to investigate the antimicrobial effect of Moringa oleifera leaves aqueous extract (0.5%, 1%, and 2%) on ground beef during refrigerated storage at 4 °C for 18 days. MLE revealed potent antimicrobial properties against spoilage bacteria, such as aerobic plate count and Enterobacteriaceae count. MLE 2% showed a significant (p < 0.01) reduction in the counts of E. coli O157:H7, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus artificially inoculated to ground beef by 6.54, 5.35, and 5.40 log10 CFU/g, respectively, compared to control, by the 18th day of storage. Moringa leaves extract (MLE) had no adverse effect on the overall acceptability and other sensory attributes; moreover, it induced a slight improvement in the tenderness and juiciness of treated ground beef, compared to the control. Therefore, MLE can be used as a healthy, natural, and safe preservative to increase meat products’ safety, quality, and shelf stability during cold storage. A promising approach for using natural food additives rather than chemical preservatives could begin new frontiers in the food industry, as they are more safe and do not constitute health risks to consumers.

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Posted in Antibacterial, Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella, Staphylococcus aureus

Research – Zoonoses, foodborne outbreaks and antimicrobial resistance guidance for reporting 2022 data

Posted on January 30, 2023 by | Leave a comment

EFSA

Abstract

This technical report of the European Food Safety Authority (EFSA) presents the guidance to reporting European Union (EU) Member States and non‐Member States in data transmission using extensible markup language (XML) data transfer covering the reporting of isolate‐based quantitative antimicrobial resistance data, as well as reporting of prevalence data on zoonoses and microbiological agents and contaminants in food, foodborne outbreak data, animal population data and disease status data. For data collection purposes, EFSA has created the Data Collection Framework (DCF) application. The present report provides data dictionaries to guide the reporting of information deriving from 2022 under the framework of Directive 2003/99/EC, Regulation (EU) 2017/625, Commission Implementing Regulation (EU) 2019/627 and Commission Implementing Decision (EU) 2020/1729. The objective is to explain in detail the individual data elements that are included in the EFSA data models to be used for XML data transmission through the DCF. In particular, the data elements to be reported are explained, including information about the data type, a reference to the list of allowed terms and any additional business rule or requirement that may apply.

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Posted in antimicrobial resistance, Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – Manual for reporting on zoonoses and zoonotic agents, within the framework of Directive 2003/99/EC, and on some other pathogenic microbiological agents for information derived from the year 2022

Posted on January 30, 2023 by | Leave a comment

EFSA

Abstract

This reporting manual provides guidance to European Union (EU) Member States (MSs) for reporting on zoonoses and zoonotic agents in animals, food and feed under the framework of Directive 2003/99/EC, Regulation (EU) 2017/625, Commission Implementing Regulation (EU) 2019/627 and of Commission Delegated Regulation (EU) 2018/772 and also on the reporting of other pathogenic microbiological agents or contaminants in food. The objective of this manual is to harmonise and streamline reporting by MSs to ensure that the data collected are relevant and comparable for analysis at the EU level. This manual covers all the zoonoses and zoonotic agents included under the current data collection system run by the European Food Safety Authority (EFSA). Detailed instructions are provided on the reporting of data in tables and information in text forms. The instructions given relate to the description of the sampling and monitoring schemes applied by the MSs, as well as the monitoring results. Special reference is made to data elements which allow trend watching over time and the analysis of sources of zoonotic agents at the EU level. This manual is specifically aimed at guiding the reporting of information deriving from the year 2022.

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Posted in antimicrobial resistance, Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Zoonosis

Research – Protective Bacterial Culture Could Target Foodborne Superbugs

Posted on January 16, 2023 by | Leave a comment

Laboratory Equipment

Key points:

  • Researchers examined the ability of a protective culture—Hafnia alvei B16—in the prevention of infection by Salmonella.
  • According to the findings, Hafnia alvei B16 reduced Salmonella’s ability to invade human intestinal cells by nearly 90%.
  • The study also found differences in gene expression and how the two serovars responded to the protective culture in milk.

A new study published by University of Connecticut researchers builds upon our understanding of the ability of a protective culture called Hafnia alvei B16 to prevent infection by two Salmonella serovars, a grouping within the Salmonella enterica species. The serovars studied are common culprits in foodborne illness outbreaks and are resistant to multiple antibiotics.

Presently, most of the protective cultures on the market target gram-positive bacteria rather than gram-negative ones. gram-positive protective cultures are most effective against gram-positive pathogens, meaning there is a need for effective protective cultures against gram-negative pathogens, like E.coli and Salmonella.

In the study, published in Food Microbiology, the team found the Hafnia alvei worked differently than other protective cultures. Most cultures produce antimicrobial metabolites that stop the growth of competing bacteria. Meanwhile, when Hafnia alvei’s metabolites were added to a pathogenic culture, it didn’t stop their growth as expected. But, when the entire Hafnia alvei bacterium was in the presence of E. coli or Salmonella, it did. This told the team it was inhibiting the pathogen’s growth through some other mechanism.

D’Amico’s lab found that growth in the presence of Hafnia alvei decreased the expression of virulence genes in Salmonella and reduced the pathogen’s ability to invade human intestinal cells by nearly 90%.

The same study found differences in how the serovars responded to the protective culture in milk, which may impede the culture’s ability on a global level.

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Posted in Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Hafnia alvei, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella

Research – Study on bacterial infection in older individuals

Posted on January 14, 2023 by | Leave a comment

News Medical

The older population is prone to microbial infections, which can lead to death. Hence, it is important to understand why this group is vulnerable to microbial infection, especially bacterial infection. A recent Scientific Reports study linked data from two sources to understand the determining factors for microbial infection in the older population in the UK.

The prevalence of bacterial infection significantly increases with age. According to English surveillance data, the incidence of Escherichia coli (E. coli) bacteria is around ten times more in men who are between 45 and 64 years of age and around 100 times more in men above 75 years of age, compared to the younger age group, i.e., those between 15 and 44 years of age. Similar trends were observed with Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes bacteria.

Currently, there is no clear explanation for why older individuals are more vulnerable to microbial infections. Nevertheless, environmental risk factors, such as nutrition, lifestyle, and housing, have been deemed possible contributing factors. In addition, the levels of C reactive proteins (CRP) could contribute to individual infection risk.

Serological studies have indicated that aging is associated with a gradual decrease in adaptive immunity, i.e., T-cell responses and antibody levels, which leads to an increase in pneumococcal pneumonia and herpes zoster infections.

In addition to radiological imaging, microbiological sampling (e.g., blood, urine, sputum, peritoneal fluid, and cerebrospinal fluid) can also be used to diagnose an infection by identifying the causal organism of the infection. In England, microbiological specimens are typically processed in hospital laboratories under the National Health Service.

About the Study

The current study used a large-scale population cohort, namely the UK Biobank (UKB), to understand the determining factors of bacterial infection and how it influences subsequent health-related problems.

UKB is a prospective cohort that contains information on around 500,000 men and women aged between 40 and 69 between 2006 and 2010. Initially, this cohort was designed to evaluate the environmental and genetic determinants that lead to common life-threatening diseases.

Public Health England (PHE) has established a second-generation surveillance system (SGSS) to monitor and improve public health. The SGSS dataset contains regularly updated information on human pathogens, such as Campylobacter, Salmonella, and other foodborne pathogens. Additionally, it contains antimicrobial test reports against important pathogens.

The current study demonstrated the possibility of linking UKB prospective cohort data with a national dataset containing information on microbial culture in England (SGSS).

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Posted in antimicrobial resistance, Antimicrobials, Bacterial Infections, Campylobacter, E.coli, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella