Food Safety & Disease

Cronobacter sakazakii: A Deadly Pathogen with a Complex History

By foodmicrobiologyacademyPosted on March 21, 2025Posted in Food Safety & DiseaseTagged food industry, food microbiology, Food safety, foodborne disease, pathogenNo Comments

This blog article was created with Perplexity.ai, using the following prompt. The initial draft was only about 1 000 words long. Perplexity was then asked to double the length and include information on case histories. It then increased the word count by approximately 50%, as per below. Create a 2000 word blog article on Cronobacter sakazakii. Include information on history, taxonomy, when it changed name from Enterobacter, natural sources of this species, prevalence around the world, some notable outbreaks that are not linked to infant formula, while infant formula is such a common vehicle of infection, some typical case histories to show the clinical presentation and mortality rate, ways it can be controlled and options for treating the disease along with vaccination. Include cited sources of information. Cronobacter sakazakii is a foodborne pathogen that has gained significant attention in recent years due to its association with severe infections, particularly in infants. This comprehensive article delves into the history, taxonomy, prevalence, and clinical significance of C. sakazakii, as well as strategies for control and treatment. Historical Background The story of C. sakazakii begins in 1950 when a strain of Enterobacteriaceae was isolated from a tin of dried milk and deposited in England’s National Collection of Type Cultures (NCTC). This strain, designated NCTC 8155, would later be identified as C. sakazakii biogroup 1 and represents the earliest documented isolate of Cronobacter from a food source7. The first strain isolated from a human clinical specimen was in 1953, but it wasn’t until 1958 that the first documented case of neonatal meningitis occurred7. In 1961, Urmenyi and Franklin reported the first Cronobacter infection, though at the time it was misidentified as a yellow-pigmented Enterobacter cloacae. It wasn’t until 1980 that John J. Farmer III proposed the name Enterobacter sakazakii for this organism, honoring Japanese bacteriologist Riichi Sakazaki. This marked the beginning of a new era in understanding this pathogen and its impact on human health. Taxonomy and Reclassification For nearly three decades, from 1980 to 2007, Enterobacter sakazakii was considered a single well-defined bacterial species with 15 biogroups. However, advances in molecular biology techniques led to a significant taxonomic revision in 2007. The use of 16S ribosomal RNA gene sequencing, hsp60 sequencing, and polyphasic analysis revealed that E. sakazakii isolates actually represented distinct species. DNA-DNA hybridization and phenotyping confirmed these findings, leading to the creation of the new genus Cronobacter. The genus Cronobacter was named after Cronos, the Titan of Greek mythology who devoured his children as they were born – a grim allusion to the organism’s impact on infants. C. sakazakii became the type species of this new genus. Current Taxonomy Today, the genus Cronobacter contains 10 different species: The clinically relevant species can be divided into two groups: The other six species are primarily environmental commensals and appear to be of little clinical significance. Natural Sources and Prevalence C. sakazakii is naturally found in the environment and is particularly adept at surviving in low-moisture, dry foods. Common sources include: A meta-analysis of prevalence studies revealed that Cronobacter spp. are more prevalent in plant-related sources (20.1%, 95% CI 0.168–0.238) compared to animal-originated sources (8%, 95% CI 0.066–0.096)1. Alarmingly, a recent survey in the United States found that approximately 26.9% of homes were contaminated with C. sakazakii, particularly in kitchen settings. Common sites of contamination include: This widespread presence in the domestic environment creates clear opportunities for contamination of food and infant formula, potentially leading to foodborne illnesses. Notable Outbreaks and Case Histories While Cronobacter infections are often associated with powdered infant formula, outbreaks have occurred in various settings and age groups. Here are some notable cases and outbreaks: The Netherlands, 1977-1981 One of the first large series of neonatal infections was reported in the Netherlands, comprising eight cases of meningitis and sepsis over a 4-year period1. Reykjavik, Iceland, 1986-1987 Three cases of C. sakazakii infections in neonates were reported in Reykjavik, Iceland1: Case 1: A male born on March 18, 1986, after 36 weeks of gestation, with a birth weight of 3 144 g. Initially healthy, he was fed breast milk and powdered infant formula. On day 5, his health deteriorated, and C. sakazakii was isolated from spinal fluid and blood. Despite treatment with multiple antibiotics, the patient suffered severe neurological impairment. Case 2: A male born December 14, 1986, with Down’s syndrome, developed a C. sakazakii infection after being fed reconstituted powdered infant formula. Despite treatment, the patient did not survive. Case 3: A male twin born on January 6, 1987, developed a fever on day 6. C. sakazakii was isolated from cerebrospinal fluid samples. Oklahoma City, Oklahoma, 1981 A five-week-old male was admitted to the hospital with fever, grunting, and fatigue. C. sakazakii was detected in cerebrospinal fluid, blood, and urine samples. The patient was treated with antibiotics and discharged in good condition after 14 days1. United States, 2021-2022 Two recent cases highlight the ongoing threat of C. sakazakii infections2: Case 1 (September 2021): A full-term male infant developed fever, irritability, and excessive crying at 14 days old. C. sakazakii was isolated from cerebrospinal fluid. The infant was treated with intravenous antibiotics for 21 days and made a full recovery. Case 2 (February 2022): A preterm male infant in the neonatal intensive care unit developed apneic and bradycardic episodes, temperature elevation, and seizures at 20 days old. Despite treatment, the patient died 13 days after illness onset. Egypt, 2017-2018 A study conducted in Egypt reported 12 cases of neonatal sepsis caused by C. sakazakii out of 100 cases examined. This marked the first reported cases of C. sakazakii-induced neonatal sepsis in Egypt3. Infant iormula as a vehicle of infection Powdered infant formula (PIF) has been a common vehicle for C. sakazakii infections in infants for several reasons: In the 2021 case mentioned earlier, whole genome sequencing (WGS) revealed that the C. sakazakii isolate from the patient was closely genetically related (0 SNPs apart) to an isolate from the powdered formula consumed by the infant2. Clinical Presentation and Mortality Rate C. sakazakii

Bacteriocins as Antibiofilm Agents: An Analysis of Feasibility

By foodmicrobiologyacademyPosted on February 28, 2025Posted in Food Safety & DiseaseTagged food industry, food microbiology, Food safety, food science, foodborne diseaseNo Comments

Biofilm formation is a significant challenge in the food manufacturing industry. These microbial communities, encased in a self-produced matrix of extracellular polymeric substances (EPS), are notoriously difficult to eliminate. They can adhere to food contact surfaces, leading to contamination and posing severe risks to food safety. Traditional cleaning and sanitising methods are often ineffective against biofilms, making it essential to explore novel strategies for their control. Among the emerging solutions, bacteriocins garnered considerable attention due to their potential as antibiofilm agents. Understanding Bacteriocins and Their Mechanism of Action Bacteriocins are produced by various bacterial species, primarily lactic acid bacteria (LAB), which are commonly found in fermented foods. These peptides exhibit a broad spectrum of antimicrobial activity against closely related bacterial strains and, in some cases, even against more distantly related bacteria. The primary mechanism by which bacteriocins exert their antibacterial effects is through pore formation in the target cell membrane, leading to cell lysis and death. However, the role of bacteriocins in disrupting biofilms goes beyond simple bacterial killing. Recent studies have demonstrated that bacteriocins can interfere with biofilm formation at multiple stages, including initial adhesion, maturation, and dispersion. This multifaceted mode of action makes bacteriocins promising candidates for biofilm control in food processing environments. Efficacy of Bacteriocins Against Foodborne Pathogen Biofilms Several studies have investigated the effectiveness of bacteriocins against biofilms formed by foodborne pathogens. For instance, bacteriocin-producing strains such as Lactobacillus plantarum have shown the ability to inhibit the biofilm formation of Listeria monocytogenes, a notorious foodborne pathogen. The bacteriocins produced by these strains were found to disrupt the EPS matrix, rendering the biofilm structure more susceptible to sanitizing agents (Pang et al., 2022). Similarly, nisin, one of the most well-characterized bacteriocins, has been extensively studied for its antibiofilm properties. Nisin has been shown to inhibit the growth of biofilms formed by Staphylococcus aureus and Escherichia coli, two pathogens commonly associated with foodborne illnesses. The peptide’s ability to penetrate the biofilm matrix and disrupt the membrane integrity of embedded cells makes it an effective tool for biofilm control (Simons et al., 2020). Challenges and Considerations in Implementing Bacteriocins in Food Manufacturing Despite the promising results, the application of bacteriocins as antibiofilm agents in food manufacturing is not without challenges. One of the primary concerns is the potential development of resistance among target bacteria. Just as with antibiotics, prolonged exposure to sub-lethal concentrations of bacteriocins could select for resistant strains, potentially undermining their efficacy. Moreover, the stability of bacteriocins under various food processing conditions, such as high temperatures and varying pH levels, needs to be carefully evaluated. While some bacteriocins are relatively stable, others may lose their activity when exposed to harsh processing environments. This variability in stability must be accounted for when designing bacteriocin-based interventions. Another critical factor is the regulatory landscape. The use of bacteriocins in food products is subject to strict regulations, which vary by region. Manufacturers must navigate these regulations to ensure that their use of bacteriocins complies with safety standards and does not pose risks to consumers. Future Directions and Conclusion The feasibility of using bacteriocins as antibiofilm agents in food manufacturing is supported by a growing body of evidence. These peptides offer a natural and potentially effective means of controlling biofilms, which could complement existing sanitation practices and enhance food safety. However, further research is needed to address the challenges associated with their application, including the risk of resistance development, stability under processing conditions, and regulatory compliance. As the food industry continues to seek innovative solutions to ensure the safety and quality of food products, bacteriocins represent a promising avenue for exploration. By leveraging the natural antimicrobial properties of these peptides, manufacturers can potentially reduce the incidence of biofilm-related contamination, ultimately protecting public health and preserving the integrity of the food supply chain. References:

Botulism: A Rare but Deadly Disease

By foodmicrobiologyacademyPosted on February 19, 2025Posted in Food Safety & DiseaseTagged food microbiology, Food safety, foodborne disease, microbiologyNo Comments

Botulism is a rare but highly serious illness that can be fatal if not properly and promptly treated. This disease is caused by a neurotoxin that is produced by the Clostridium botulinum bacteria. There are three main types of botulism: foodborne botulism, wound botulism and infant botulism. To prevent botulism, it is important to first understand the bacterium causing the disease. This article provides an overview on the bacterium Clostridiumbotulinum, the causes and symptoms of botulism, along with useful information on treatment and prevention strategies. The Clostridium botulinum bacteria Clostridium botulinum is a Gram positive bacterium that has a rod shaped (bacillus) cell morphology. It is a type of anaerobic bacteria that can undergo sporulation and also has the ability to produce a type of neurotoxin known as the botulinum toxin. This botulinum toxin is typically produced by Clostridium botulinum during low oxygen conditions and released into their environment. Causes and Transmission of botulism As mentioned previously, anaerobic conditions trigger Clostridium botulinum to produce the botulinum neurotoxin. This neurotoxin is the main cause for the onset of symptoms seen in a person infected with the bacteria. Transmission routes vary depending on the specific type of botulism. For example, ingestion of contaminated foods, such as improperly canned foods, can cause a person to become infected with the bacteria and they may then go on to infect others around them. It can also be spread through wound contamination or ingestion of spores by an infant. Some commonly used methods to diagnose botulism include clinical evaluation, along with detection of the botulinum toxin in serum or stool samples. Symptoms of Botulism There are multiple symptoms of botulism that can be observed in an infected person. These may include blurred or reduced vision, difficulty in swallowing and speech, along with muscle weakness. Paralysis may also occur in more severe cases of botulism. The onset of botulism also depends on the type of botulism. Notably, it should be highlighted that foodborne botulism infections normally have a more rapid onset. The reason for this is due to the ingestion of botulinum toxins that are already previously produced and secreted by the bacterium. This can be compared with infant and wound botulism, which have a more gradual onset. This is because they are a result of the ingestion or contamination of bacterial spores, which require time to germinate before producing the toxins locally, either within the gastrointestinal tract or the infected wound area. Treatment for botulism Treatment approaches are currently available, but they typically require early detection and diagnosis. An example of an effective treatment that may be used to target botulism is the administration of botulism antitoxins. These are helpful as they mainly act to neutralise circulating toxins in the body of an infected person. A range of supportive care measures can also be taken for more severe cases of botulism, such as providing respiratory support and feeding assistance to infected patients. Prevention strategies against botulism One of the major preventive measures for botulism is ensuring proper home canning techniques for different foods. This is especially the case to prevent foodborne botulism. As for wound botulism, it is important to practise appropriate wound cleaning and care following injuries. Another lesser known, but highly important measure to prevent botulism in infants is to avoid feeding infants that are under one year of age with honey. The main reason for this is because the bacterium Clostridium botulinum may be found in honey and related food products. Furthermore, general public health measures such as active surveillance, prompt investigation of botulism outbreaks, and proper education on safe food handling practices are also highly crucial in order to prevent future botulism outbreaks within a community or population. Conclusion There is much ongoing research efforts that are being done on Cholera and the bacterium Clostridium botulinum. These include the development of more effective vaccine treatments and other antitoxins to specifically target Clostridium botulinum. As this is a potentially fatal disease that can be prevented, it is paramount to have a good understanding of the bacteria that is involved in this disease. This article hopes to reinforce the public’s awareness on this disease, along with highlighting the importance of making necessary interventions and taking preventive measures against it in order to stop the spread of botulism disease.

食源性疾病的重要性

By foodmicrobiologyacademyPosted on February 13, 2025Posted in Food Safety & DiseaseTagged food microbiology, Food safety, food science, foodborne disease, microbiologyNo Comments

1. 全球影响每年，全球有数亿人因食源性疾病而受到影响。根据世界卫生组织（WHO）的数据，每年大约有6亿人患上食源性疾病，其中约有42万人因此死亡。这些疾病包括细菌、病毒、寄生虫和化学物质引起的广泛感染，如沙门氏菌、诺如病毒、弯曲杆菌、李斯特菌等。食源性疾病不仅影响发展中国家，在发达国家也同样存在严重问题。 Estimating the burden of foodborne diseases (who.int) 2. 经济负担食源性疾病带来的经济损失是巨大的。医疗费用、失去的生产力、食品产业的损失以及贸易限制等都是由食源性疾病引起的直接经济影响。例如，美国疾病控制与预防中心（CDC）估计，美国每年因食源性疾病导致的经济损失达数百亿美元。发展中国家的情况更为严峻，由于医疗资源有限，食源性疾病往往导致更高的病死率和更严重的经济影响。 Economic burden from health losses due to foodborne illness in the United States – PubMed (nih.gov) 3. 公共卫生系统的挑战食源性疾病的频繁暴发揭示了公共卫生系统在监测、预防和响应方面的不足。加强食品安全监管、改进疾病监测系统和增加公共卫生投入是应对这些挑战的关键。许多国家已经采取行动，例如欧盟实施了严格的食品安全法规，美国推出了《食品安全现代化法案》（FSMA），旨在防止食品污染和保障消费者安全。 4. 预防与控制预防和控制食源性疾病需要全面而系统的策略： Food Safety Strategies: The One Health Approach to Global Challenges and China’s Actions – PMC (nih.gov) 结论食源性疾病的重要性不仅体现在对个人健康的直接影响，还包括其对全球经济、社会和文化的广泛影响。通过加强食品安全监管、提高公众意识、改进公共卫生系统以及国际合作，我们可以有效减少食源性疾病的风险，保护全球公共卫生安全。这一任务需要全球各国政府、食品行业和消费者的共同努力，以确保未来的食品供应链更加安全可靠，保障全球公民的健康和福祉。

Bacteriocins as Antibiofilm Agents: The Mode of Actions

By foodmicrobiologyacademyPosted on February 10, 2025Posted in Food Safety & DiseaseTagged food industry, food microbiology, Food safety, food science, foodborne disease, microbiologyNo Comments

Biofilms, complex communities of microorganisms encased in a self-produced extracellular polymeric substance (EPS), pose significant challenges in various industries, including food safety. These biofilms confer enhanced resistance to antibiotics and other antimicrobial agents, making them a persistent problem. In recent years, bacteriocins, a group of antimicrobial peptides produced by bacteria, have garnered attention for their potential to disrupt and prevent biofilm formation. This article delves into the mechanisms by which bacteriocins act as antibiofilm agents, based on insights from recent research. Understanding Biofilms Biofilms are structured communities of microbial cells that adhere to surfaces and are embedded in a protective EPS matrix. This matrix not only shields the bacteria from environmental stresses but also facilitates communication and nutrient exchange among the cells. Biofilms can form on both biotic and abiotic surfaces, including medical devices, food processing equipment, and natural environments. The inherent resistance of biofilms to conventional antibiotics and disinfectants is a major concern, particularly in clinical and food safety settings. Mechanisms of Antibiofilm Action Bacteriocins utilise multiple strategies to combat biofilms, targeting different stages of biofilm development: 1. Inhibition of Initial Adhesion Bacteriocins can prevent the initial attachment of bacterial cells to surfaces, a critical first step in biofilm formation. By interfering with cell surface structures and reducing surface hydrophobicity, bacteriocins hinder the ability of bacteria to adhere to surfaces. 2. Disruption of EPS Matrix The EPS matrix is essential for biofilm stability and protection. Bacteriocins can degrade components of the EPS, such as polysaccharides and proteins, thereby weakening the biofilm structure and making the embedded bacteria more susceptible to antimicrobial agents. 3. Pore Formation in Cell Membranes Many bacteriocins, such as nisin, exert their antimicrobial effects by forming pores in the bacterial cell membrane. This leads to the leakage of cellular contents, disruption of membrane potential, and ultimately cell death. This mechanism is particularly effective against biofilm cells, which are often in a dormant state and resistant to other antimicrobials. 4. Interference with Quorum Sensing: Quorum sensing is a cell-to-cell communication mechanism that regulates biofilm formation and maintenance. Bacteriocins can interfere with quorum sensing signals, disrupting the coordination required for biofilm development and maintenance. 5. Synergistic Effects with Other Antimicrobials: Bacteriocins can enhance the efficacy of other antimicrobial agents when used in combination. This synergistic effect can help overcome the resistance of biofilm-associated bacteria, making it a promising strategy for biofilm control. Applications in Food Safety In the food industry, biofilms can lead to contamination and spoilage, posing significant health risks. The use of bacteriocins as natural preservatives and biofilm control agents offers a promising solution. For instance, nisin-coated surfaces have been shown to effectively reduce biofilm formation by Listeria monocytogenes and Staphylococcus aureus on food processing equipment. Additionally, bacteriocins can be incorporated into packaging materials to extend the shelf life of food products by preventing biofilm formation. To explore more about how bacteriocins contribute to food safety and their broader applications in the industry, check out our related articles: Conclusion Bacteriocins represent a potent and versatile tool in the fight against biofilms. Their ability to target multiple stages of biofilm development and their synergistic effects with other antimicrobials make them valuable in both clinical and food safety applications. Continued research into the mechanisms of action and the development of novel bacteriocins will further enhance our ability to control biofilms and improve public health outcomes. By leveraging the natural antimicrobial properties of bacteriocins, we can develop more effective strategies to combat biofilm-related issues, ensuring safer food production and processing environments. Stay Ahead in Biofilm Control and Food Safety Bacteriocins are proving to be powerful tools in tackling biofilms, but their full potential is still being explored. As industries continue to adopt innovative antimicrobial strategies, staying informed is crucial. Want to keep up with the latest advancements in food microbiology and biofilm control? Subscribe to our newsletter or follow us for more research insights and practical applications in food safety. Let’s work towards safer and more sustainable food production—one breakthrough at a time!

Cronobacter sakazakii: A Deadly Pathogen with a Complex History

Bacteriocins as Antibiofilm Agents: An Analysis of Feasibility

Botulism: A Rare but Deadly Disease

食源性疾病的重要性

Bacteriocins as Antibiofilm Agents: The Mode of Actions

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