Anaerobic Spore-Forming Gram-Positive Bacilli PDF

Anaerobic Organisms: Spore and Non-Spore Formers by Heba Rashed  What are anaerobic organisms? Anaerobic organisms are living beings that Instead, they obtain energy through can survive and thrive in environments different pathways, such as fermentation lacking oxygen....

Anaerobic Organisms: Spore and Non-Spore Formers by Heba Rashed  What are anaerobic organisms? Anaerobic organisms are living beings that Instead, they obtain energy through can survive and thrive in environments different pathways, such as fermentation lacking oxygen. or anaerobic respiration, using alternative electron acceptors. These organisms do not require oxygen for They can be found in various their metabolic processes, unlike their environments, including soil, water, and aerobic counterparts. the human gut.  Differences Between Aerobic and Anaerobic Organisms Oxygen Requirements Energy Production 1 2 Aerobes require oxygen for survival, while Aerobes use oxygen to generate energy, while anaerobes do not. anaerobes rely on other processes. 3 Metabolic Pathways 4 Sensitivity to Oxygen Aerobes use oxidative phosphorylation, while Anaerobes can be inhibited or even killed by anaerobes use fermentation. the presence of oxygen.  Non-Spore Forming Anaerobes Bacteroides Fusobacterium Peptostreptococcus These bacteria are found These gram- This genus of in the human gut and are negative anaerobic anaerobic cocci is also often associated with bacilli are often a frequent inhabitant of infections related to the the human implicated in digestive system. They microbiome, periodontal disease are particularly prevalent particularly in the and other infections in the mouth, colon, and gastrointestinal tract vagina. involving the oral and oral cavity. cavity. Bacteroides species Bacteroides species are gram-negative, anaerobic bacteria that are commonly found in the human gastrointestinal tract. These bacteria are typically commensal and play a role in maintaining gut health. However, certain Bacteroides species can become opportunistic pathogens, causing infections in various parts of the body. Actinomyces is a genus of Gram-positive filamanteous branching bacilli, non- spore forming Some species are anaerobic, while others are microaerophilic. The important species is Actinomyces israelii It cause actinomycosis : abscess The organism form mycelial masses that protrude from the sinus and are known as sulphur granules Sulphur granules visible in yellow color Sulphur granules are crushed between 2 slides to prepare Gram stain film that show gram positive mycelia Culture Sulphur granules are cultured on blood agar for10 days. Spider colonies are identified Spore-Forming Anaerobes Spore Formation Survival Mechanism Germination Spore-forming anaerobes are Spores can withstand harsh When favorable conditions return, bacteria that produce dormant, environmental conditions, such spores germinate and produce highly resistant structures called as heat, desiccation, and vegetative bacteria, which can spores. disinfectants. then cause infection.  Anaerobic Spore-forming Gram-positive Bacilli (Genus Clostridium) Clostridia are gram-positive spore forming anaerobic bacteria Natural habitat: –Intestinal tract of human and animals –saprophytic in soil and water Medically important Colstridia: Cl. tetani causing tetanus Cl. perfringens causing gas gangrene and food poisoning Cl. botulinum causing botulism Cl. difficile causing antibiotics associated diarrhea Tetanus Causative organism : Clostridium tetani Morphology: Gram positive bacilli Anaerobic Motile Non capsulated Have terminal spores – drumstick shape. Habitat Soil and intestinal tract of human and animals Culture characters Cl. tetani grows in cooked meat medium and produce thin film (when grow on blood agar ) The organism produce exotoxin Gram stained film demonstrating drum stick spores of Cl. tetani Laboratory diagnosis Specimen – wound exudate Direct smear shows Gram-positive bacilli with drum stick appearance Culture: culture the specimen on Robertson cooked meat medium , incubated overnight at 37 °C then subculture on blood agar and incubated anaerobically at 37 °C Cl. tetani produce thin film or swarming ; they are α hemolytic followed by β-haemolysis The colonies identified by motility test ( positive ) Slowly gelatin liquefication  Cl. tetani produce thin film or swarming ; they are α hemolytic followed by β-haemolysis The colonies identified by motility test ( positive ) Slowly gelatin liquefication Specimen Collection and Transport 1 Maintaining 2 Transport Media Anaerobiosis Specialized transport media, Anaerobic organisms are like GasPak jars, maintain an sensitive to oxygen, so anaerobic environment. proper collection techniques are crucial. 3 Rapid Delivery Prompt delivery of specimens to the laboratory is essential for accurate results. Difficulties in Specimen Collection 1 Oxygen Exposure 2 Sampling Techniques Anaerobic bacteria are Obtaining specimens from sensitive to oxygen, requiring deep tissue or body fluid careful handling to prevent requires specialized exposure. techniques. 3 Transport Conditions Specimens must be transported in anaerobic conditions, often with specialized containers and media. Antimicrobial Resistance Increasing Threat Contributing Factors Anaerobic bacteria can develop resistance to commonly used Overuse and misuse of antibiotics, as well as the inherent antibiotics, making infections more difficult to treat. genetic properties of certain anaerobic species, contribute to resistance development. This poses a significant challenge in healthcare settings, as effective treatment options become limited. The widespread use of antibiotics in agriculture and animal husbandry also contributes to the spread of resistant strains. In which environment are Clostridium species primarily found? A. Extreme cold environments B. Urban laboratories C. Freshwater ecosystems D. Soil and intestinal tract ANSWER: D Where are Bacteroides species predominantly found? A. In the human gastrointestinal tract B. In the soil and freshwater C. In the respiratory tract D. On the skin ANSWER: A What is the shape of Clostridium tetani spores as observed under a microscope? A. Rod-shaped B. Spindle-shaped C. Coccoid D. Drumstick-shaped ANSWER: D Sulphur granules from Actinomyces can be cultured on blood agar for 10 days. A. True B. False ANSWER: A Unlike aerobes, anaerobes rely on ______ or anaerobic respiration for energy production. These anaerobic bacilli are often implicated in infections related to the ______ system. Anaerobes can be inhibited or even killed by the presence of ______. ANSWER: fermentation ANSWER: digestive ANSWER: oxygen Clostridium tetani produce thin film or swarming on cultures grown in ______ meat medium. ANSWER: cooked