Anaerobic Organisms: Spore and Non-Spore Formers PDF

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

Anaerobic Organisms: Spore and Non-Spore Formers by Heba Rashed  What are anaerobic organisms? Anaerobic organisms are living Instead, they obtain energy beings that can survive and thrive through different pathways, in environments lacking oxygen. such as fermentation or anaerobic respiration, using alternative electron acceptors. These organisms do not require They can be found in various oxygen for their metabolic environments, including soil, processes, unlike their aerobic water, and the human gut. counterparts.  Differences Between Aerobic and Anaerobic Organisms Oxygen Requirements Energy Production 1 2 Aerobes require oxygen for survival, Aerobes use oxygen to generate while anaerobes do not. energy, while anaerobes rely on other processes. 3 Metabolic Pathways 4 Sensitivity to Oxygen Aerobes use oxidative Anaerobes can be inhibited or even phosphorylation, while anaerobes use killed by the presence of oxygen. fermentation.  Non-Spore Forming Anaerobes Bacteroides Fusobacterium Peptostreptococcus These bacteria are These gram- This genus of found in the human negative anaerobic cocci is gut and are often also a frequent anaerobic bacilli associated with inhabitant of the are often infections related to human microbiome, implicated in the digestive system. particularly in the periodontal They are particularly gastrointestinal prevalent in the disease and other tract and oral cavity. mouth, colon, and infections involving the oral 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 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 bacteria that produce environmental conditions, return, spores germinate and dormant, highly resistant such as heat, desiccation, produce vegetative bacteria, structures called spores. and disinfectants. which can 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 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 ) 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 )  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 Anaerobic organisms are media, like GasPak jars, sensitive to oxygen, so maintain an anaerobic proper collection environment. 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 sensitive to oxygen, from deep tissue or body requiring careful handling fluid requires specialized to prevent 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 Overuse and misuse of antibiotics, as well as the commonly used antibiotics, making infections more inherent genetic properties of certain anaerobic difficult to treat. species, contribute to resistance development. This poses a significant challenge in healthcare settings, as effective treatment options become The widespread use of antibiotics in agriculture and limited. 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