MICROBIOLOGY AND PARASITOLOGY MICROBIOLOGY and PARASITOLOGY CHAPTER 1 - advance course in biology dealing with small living organisms or microbes - UBIQUITOUS – virtually everywhere since viruses are ACELLULAR [not composed of cells] they are often referred to as “infectious agents” or “infectious particles” rather than microorganisms Microbiology Includes the Study of… BACTERIA – BACTERIOLOGY FUNGI – MYCOLOGY VIRUSES – VIROLOGY ALGAE – PHYCOLOGY PROTOZOAN OR PROTOZOA’S – PROTOZOOLOGY Reasons for Studying Microbiology - to get to know the indigenous micro flora [beneficial bacteria] ▪ Lactobacilli – digestive tract ▪ Ecoli [non-pathogenic] – prevent other pathogenic microorganisms to get into our system - develop awareness on the presence of opportunistic pathogens or opportunists - to know that photosynthetic algae and bacteria [cyanobacteria] releases oxygen into the atmosphere Importance of Microbes - Microbes are important as decomposers or saprophytes since they aid in fertilization by returning inorganic nutrients into the soil - Microbes are used in bioremediation to clean up or decompose industrial wastes like oil spills - Microorganisms are involved in elemental cycles [carbon, nitrogen, oxygen, sulfur and phosphorus] - Microbes serve as food for smaller animals; important part of the food chain - Microbes aid in food digestion and some produces beneficial substances or solutions - Microbes are used in various industries such as food, beverage, chemical and antibiotic industries It is known as BIOTECHNOLOGY [examples are yogurt, yakult drink, wine and cheese] ḯ small bacteria and fungi produce antibiotics - Microbes are used in genetic engineering - Microbes are used as cell models - Microbes cause either infection diseases or intoxication Historical Background microscopy, staining procedures, MICROBIOLOGY laboratory procedures, culture techniques People who Contributed to the Discovery of Microbiology A. Anthony Van Leeuwenhoek - 1st to see bacteria [bacterium] and protozoa [field of lenses] - lens maker and in one of his production he saw microorganisms B. Louis Pasteur - Fermentation [eliminating bacteria] Pasteurization - discovered anaerobes - discovered infectious agents causing silkworm diseases - contributed to the germ theory of disease - championed changes in hospital practices to minimize the spread of by pathogens - developed vaccines to prevent chicken cholera, anthrax and swine erysipelas [skin disease] C. Robert Koch - discovered the germ theory of disease [Koch’s postulates] - Bacillus anthracis produces spores capable of resisting adverse conditions - developed method of fixing, staining and photographing bacteria - developed methods of cultivating bacteria on solid media - discovered mycobacterium tuberculosis and vibrio cholerae - worked on tuberculin which led to the development of a skin test valuable in diagnosing tuberculosis Careers in Microbiology Microbiology : Microbiologist Bacteriology : Bacteriologist Virology : Virologist Phycology : Phycologist Mycology : Mycologist Protozoolgy : Protozoologist Applied Microbiology [biotechnology, medical and clinical microbiology] ḯ Medical Microbiology – the study of pathogens, the disease they cause and the body’s defenses against disease concerned with epidemiology Classification of Bacteria based on DR. BERGEY - Morphology - Staining reactions - Cultural characteristics - Biochemical or Physiologic Behavior - Genetic analyses - Animal inoculations - Immunologic differences BERGEY’S MANUAL of determining BACTERIOLOGY [19 categories] 1. Phototrophic Bacteria – produce own food – photosynthesis: green pigment chlorophyll 2. Gliding Bacteria – flagella / cilia 3. Sheathed Bacteria – encloses organism : facultitively anaerobic a. Escherichia rods b. Salmonella c. Shigella d. Klebsiella e. Proteus 4. Budding or Appendaged – guides through budding [maturing] 5. Spirochetes MICROBIOLOGY AND PARASITOLOGY 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. Spiral and Curved Gram-Negative Aerobic Rods and Cocci a. Pseudomonas b. Azotobacter c. Rhizobium d. Halobacter e. Brucella f. Bordetella g. Francisella Gram-Negative Facultatively Anaerobic Rods a. Escherichia b. Salmonella c. Shigella d. Vibrio e. Klebsiella f. Enterobacter g. Pasteurella h. Serratia i. Proteur j. Yersinia k. Haemophilus Gram-Negative Anaerobic Bacteria a. Bacteriodes b. Fusobacterium Gram-Negative Cocci and Coccobacilli [aerobes] a. Neisseria b. Ecolli Gram-Negative Anaerobic Cocci Gram-Negative Chemolithotrophic Bacteria a. Nitrobacter b. Nitosomonas Methane-Producing Gram-Positive Cocci a. Staphylococcus b. Streptococcus c. Sarcina Endospore Forming Rods and Cocci a. Bacillus Clostridium – Sporosarcina [rod shaped bacteria] - produce spore Gram-Positive a. Lactobacilli Actinomycetes and related organisms a. Coryneloacterium b. Actinomyces c. Breribacterium d. Mycobacterium e. Sterptomyces Ricketisias – ricketisms Microplasmas – mycoplasmas ADAPTATION - variations that represent physiologic adjustment to the environment ATTENUATION - important form of adaptation and also important in immunology MUTATION - sudden changes in the chemical constituent of bacteria due to error in replication by the DNA strand CHAPTER 2 CELL - PROKARYOTIC [undefined nucleus; primitive; structures vary; have several functions] - EUKARYOTIC [organelles (little organs) in plants and animals] Distribution - widespread in the bodies of living organisms [skin/alimentary tract] - food, water, air, soil - adopted to every conceivable habitat [several thousand species] - about 100 species are pathogenic to man - 1:30,000 ratio of disease-producer to non-pathogenic bacteria ḯ PATHOGENICY - those that produce disease in man and lower animals - those that attack lower animals alone - those that attack only plants - those that attack lower animals and transferable to man Structural Components 1. CELL WALL – rigid; made up of peptidoglycan [nurein/mucopeptide] – made up of alternating amino sugars Gram + bacteria = peptidoglycan layer in 3 dimensions Gram – bacteria = peptidoglycan layer forming 2 dimensional monolayer Gram + cell walls = large amounts of teichoic acids Gram – cell walls = no teichoic acids 2. – – – – – – PLASMA MEMBRANE made up of phospholipids and proteins site of important enzyme systems assume function of mitochondria aided by respiratory enzymes regulates passage of food or materials and metabolic by-products blocks entry of toxic substances catalyzes transport of substances 3. – CAPSULE made up of complex polysaccharides a. slime layer – when the mucilaginous envelope is indistinct b. capsule – well-developed mucilaginous envelope [protein/mucin] – streptococcus pneumonia MICROBIOLOGY AND PARASITOLOGY clostridium petringens – – – 4. – – – increases the virulence of organisms gives the organisms its specific immunologic nature Gram (+) positive capsule formers METACHROMATIC GRANULES enzymatically active reserves of inorganic phosphates stored as polymerized metaphosphate (volutin) may be arranged or located irregularly in the bacterial cells 5. – – 6. – – – – MYCOBACTERIUM TUBERCULOSIS NUCLEUS contains the genetic codes that is pass from generation to the next governing force for the bacterial cell in all its vital activist MOTILITY [FLAGELLA] true motility seldom observed in cocci Bacilli spirilla – generally motile presence of hair like appendages Types of Motility - monotrichou – 1 flag - peritrichous – several Salmonella typhi - lophotrichous – few to many flag arranged in a tuft like shape Proteus vulgaris 7. – – 8. – – – – – – – – PILI [HAIRS] hair-like structures; surface projection found in gram (-) negative bacteria called fimbriae – made of a polymerized protein molecules called pili cell in conjugation ENDOSPORES protective mechanisms resistant to adverse condition common in bacilli except in gram (+) positive cocci sporosarcina 150 species of spore formers belonging to bacilli and clostridium cause tetanus [clostridium tetani], gas gangrene [perfringins], botulism [botulinum] and anthrax [bacillus anthracis] spore formation is affected by temperature Phases in Spore formers a. vegetative phase – phase where endospores are not forming b. sporulating phase – phase where spores are forming spores are resistant to heat chemicals and drying Bacterial Reproduction - Asexual process – simple transverse division (binary fission) - example: staphyloco - staphylococ Steps - replication of nuclear chromosome - active membrane synthesis at the periphery - transverse membrane moves into the bacterium - constriction of membrane along its short axis - formation of 2 daughter cells formed by deepening constrictions - separated cell elongates to full size and in turn 2 dividers - 20 – 30 minutes regeneration period variation in microbes - deviation from the parent form in bacteria of the same species - caused by external or internal influences (inherent) - type of culture medium - length of time grown artificially -exposure to chemicals, radiation (x-rays) - affects cell biologic properties colonial characteristic and physiologic - may be temporary or permanent Pathogenic Clostridium tetani Clostridium botulinum Clostridium pertriogins - tetanus - food poisoning - gas gangrene Biologic Attributes of Bacteria 1. Sufficient food of the proper kind 2. Moisture – provider of body fluids 3. Temperature suitable for the species 4. Proper degree of alkalinity or acidity - Best pH for bacteria – slightly alkaline [8.0 or 8.5] 5. Oxygen requirements 6. Light availability 7. Control of by-products of bacterial growth Nutritional Requirements: Proteins – 50% of bacterial cell Fats Carbohydrates – determine important traits of organism Nitrogen – 10% Carbon Growth Factors Mineral Salts [Calcium, P, Fe, Mg, K, Na] Source of Energy Kinds of Organisms according to where nourishment is obtained Saprophytes – from non-living organic matter Parasites – depend on living matter for sustenance Facultative Saprophytes – usually obtains nourishment from living matter but may obtain it from dead organic matter MICROBIOLOGY AND PARASITOLOGY Facultative Parasites – usually obtain nourishment from dead organic matter but may obtain it from living matter Heterotrophs / Organotrophs – obtain their nourishment by breaking down organic matter into simpler chemical substances Autotrophs / Lithotrophs – obtain nutrients by building the organic compounds in the protoplasm from simpler inorganic substances Moisture: - 75-80% of bacterial cell is water - needed to dissolve food materials in the environment for them to be absorbed - DRYING – detrimental to bacterial growth Temperature: Optimum – best temp for growth Minimum – lowest temp at which the species will grow Maximum – highest temp; at which growth is still more possible. - 20° C – lowest temp. of which they can multiply - 42 – 45° C – highest temp. where bacteria can multiply [mesophiles] Thermophiles [heat-loving species] – grow at temp. above 45° C or even higher Psychrophiles / Cryophiles [cold-loving species] – grow at temp. just above the freezing point [20° C or less] Cold Retards or stops bacterial growth thus employed in the process of refrigeration in order to prolong the spoilage of food. pH / Hydrogen Ion Concentration: - bacteria prefer a slightly alkaline medium for growth - Oxygen requirements: Aerobes – grow in the presence of free atmospheric oxygen Anaerobes – obtain there oxygen from oxygen-containing compounds Obligate aerobes – cannot develop in the absence of free oxygen Obligate anaerobes – cannot develop in the absence or free oxygen : intermediate Facultative organisms – adaptable either to the presence or absence of atmospheric oxygen Microaerophiles – organisms that can grow even in lowered oxygen content in the air : normal content – 16% lower Caprophiles – need 3-10% increase in oxygen content in the air to initiate developmen - Light requirements: Red/Yellow – little bactericidal effect Green – less killing action Violet Ultraviolet Highly destructive to Blue bacteria Some saprophytic species use light autotrophic activity BY-PRODUCTS OF BACTERIAL GROWTH: - Bacterial metabolism – deplete food supply & release products that inhibit further bacterial growth \Ex.: production of organic acids as in the pickling industry ELECTRICITY & RADIANT ENERGY: Electricity – heat Electric light – inhibits bacterial growth UV light roentgen rays – harmful to bacteria Chemicals: - destroy - inhibits growth - attract/repel -positive or negative chemo taxis Osmotic Pressure: - most bacteria persist small changes in osmotic pressure - killed / inhibited by high concentration of salt and sugar - employed in food preservation - Osmophiles – prefer high salt content classified as Halophiles (salt lovers) - can tolerate high concentration of salt Bacterial Interrelations 1. Symbiosis – bacteria growing well together; both parties are benefited - Synergistic relationship between staphylococci and Influenza bacilli - Legumes and Nitrogen – fixing bacteria - Nitrosumonas - Nitrobacter 2. Antagonism – presence of organisms that inhibits other major metabolic activities or it produces toxic materials that will kill organism Major Metabolic Activities ° Enzymes - 2,000 to 3,000 enzymes - under the control of the DNA apparatus / controls activity of the cell ° Chemosynthesis – processing of energy is produced through chemical alteration of some Substances 1. 2. Bacterial Digestion - Hydrolases - Hydrolysis – addition to H20 Absorption - diffusion - active transport – physiologic pumps MICROBIOLOGY AND PARASITOLOGY 3. Oxidation - preparing molecules for a possible bonding *oxidases / dehydrogenases / coenzymes cytochrome system *transfer to electrons F. Bacteriocins – bacterial protein G. Colicins – produced by the family enterobacteriaceae - act on the bacterial membrane Other effects: 1. Pigment production – important in identification of organisms not related to disease production Classes of Biologic Oxidation: Aerobic – ultimate H2 acceptor is molecular oxygen Anaerobic – H2 acceptor is inorganic nitrate, sulfate O2 carbonate Fermentation – H2 acceptor is an organic compound - uses organic compounds as both donor & electron acceptors Stapco aureus (gold) Pseudonas aeruginosa (blue-green) Halobacterium halobium (red) Serratia marcescens (red) 2. Medically Related Activities: A. Toxin Production – toxigenicity – toxicity – potency of toxins 3. Characteristics of exotoxins - protein in nature - antigenic produce antitoxin - specific cause 1 disease / nothing else Anatoxins / Toxoids – modified toxins that can still procedure immunity to the disease Endotoxins - complex lipopolysaccharides - do not promote antitoxin formation - non-specific - can’t be converted into toxoids Ex: Salmonella typhi : Neisseria meningitides 4. Harmful metabolic products 1. Hemolysing – cause lysis / break up / destruction of RBC Types: a. b. Filterable Those that are demonstrated about the bacterial colones on a culture medium containing RBC. * Hemolysis are named after the bacteria that give rise to them Ex: staphylolysin: steptolysin B. Leukocidins – destroy polynorphonuclear neutrophilic leukocytes - formed by pneumococci, streptococci and prophylococci C. Coagulase – accelerate coagulation of blood - exemplified by staphylococci - Coagulase Test – used to differentiate pathogenic from non-pathogenic bacteria D. Bacterial Kinases – act on certain components of blood to liquefy fibrin Ex: streptokinase / fibronolysin E. Hyaluronidase – make tissues more permeable to the bacteria elaborating it produced by pneumococci and streptococci Heat production – example: heating of damp hay Light production – biolumineneace : bacteria that live in water (salt) : light producers on non-pathogenic Odors – due to decomposition of material where bacteria is growing CHAPTER 3 Role in Disease INFECTION – microbes enter the human body or any plant or animal multiply in the host and produces a reaction 1. CONTAMINATION – mere presence of infectious material or constitutes normal flora of the body Infectious Diseases may be COMMUNICABLE or NONCOMMUNICABLE [based on the manner in which the causative agent reaches the body] COMMUNICABLE – causative agent directly or indirectly transmitted from host to host - example: diphtheria, tuberculosis, A(H1N1) NONCOMMUNICABLE – agent normally inhibits the body; produces the disease only when introduced into the body - example: tetanus – not communicable but infectious CONTAGIOUS – applied to diseases that are easily spread from person to person INFECTIOUS DISEASES MAY BE: EXOGENOUS – causative agent comes from outside and enters the body thru one of the portable of entry ENDOGENOUS – caused by organisms normally present in the body - occurs when defensive power of host are weakened or increased virulence of the organisms Portals of Entry 1. Skin 2. Respiratory Apparatus pulmonary tuberculosis or pneumonia or influenza viruses of measles or smallpox and German measles staphylococci or fungi MICROBIOLOGY AND PARASITOLOGY 3. Alimentary tract dysentery bacilli or cholera vibrios or amoebas of dysentery most often contacted thru food and drinks 1. FECES – salmonella, vibrio cholera, amoeba, shigella, viruses of poliomyelitis and type A hepatitis 2. 4. Genitourinary system STD’s [gonorrhea or syphilis] URINE – pyelonephritis, TB of genitourinary tract and undulant fever 3. 5. Placenta spirochete of syphilis or virus of smallpox DISCHARGES FROM MOUTH, NOSE AND RESPIRATORY PASSAGES – tuberculin, whooping cough, epidemic meningitis [pneumonia], viruses of measles [scarlet fever], small pox, mumps, polio, influenza and epidemic encephalitis 4. SALIVA – viruses of rabies Factors Influencing Occupance of Infection 1. portal of entry organisms may fail to produce a disease when introduced into the body by some other route or pathway typhoid bacilli – to be swallowed to cause infection - produces inflammation only when rubbed on the skin streptococci 2. virulence of the organisms ability of the microbes to produce the disease by overcoming the defensive powers of the host microbes are most violent when freshly discharged from an ailing person 3. number of microbes crucial to infection 4. defensive powers of the host How Microbes causes Disease ° mechanical means - occlusion of vital organs or areas ° production of biochemical effects like toxin production ELECTIVE LOCALIZATION - favored part of the body for infections dysentery bacilli – large bowel pneumococci – lungs maningo cocci – leptomeninges [brain] tissue affinity - toxins of tetanus – act on central nervous system - toxins of diphtheria – affect heart and central nervous system LOCAL EFFECTS - inflammation body’s answer to injury; designed to halt the invasion and destroy the invaders - pain, water restoration, reddening GENERAL EFFECTS - fever – tachycardia increased pulse rate - increased metabolic rate Signs of Toxicity - ANEMIA – results from prolonged and severe infections - INFECTIONS – LEUKOCYTOSIS – increased white blood cells - LEUKOPHENIA – decreased white blood cells Portals of Exit 5. BLOOD – protozoa of malaria, bacteria of tularemia, ricketisias of typhoid fever, virus of yellow fever Patterns of Infection 1. INCUBATION PERIOD – infection is received to the appearance of disease - affected by the following factors: a. nature of the agent b. virulence of host c. resistance of host d. Resistance from the site of entrance to the focus of action e. number of infectious agents invading the body 2. PRODROMAL PERIOD – short interval that follows the period of incubation - with headache and malaise 3. INVASION PERIOD – disease reaching its full development and maximum intensity regions and chills and fever - skin is pale and dry - decreased heat loss 4. FASTIGIUM or ACME – disease at its height or peak 5. DEFERVESCENCE OR DECLINE – phase where manifestations of disease subside - profuse sweating - heat loss in exceeding heat production 6. SELF-LIMITING INFECTIONS Types of Infection: A. LOCALIZED – microbes remain confined to a particular part of the body - example: boils, abscesses B. GENERALIZED – microorganisms and their products are spread generally over the body by the blood or lymphatic’s C. MIXED – caused by 2 or more organisms [primary infection + secondary infection] D. FOCAL – confined to a restricted area from which infectious material spreads to other parts of the body [infections of teeth, sinuses, prostate glands] E. INAPPARENT / SUBCLINICAL – doesn’t cause any detectable manifestations MICROBIOLOGY AND PARASITOLOGY F. LATENT – infection held in check by the defensive forces of the body but activated when body’s resistance is reduced G. INOCULATION INFECTION – infection caused by accidental or surgical penetration of the skin or mucous membranes H. BACTERMIA – bacteria enters the blood but do not multiply I. SEPTICEMIA – bacteria enters the blood and multiply causing infection of the blood [blood poisoning] J. PYEMIA – pyrogenic bacteria pus formers in blood spreads to different parts of the body and focus on a new form of disease TOXEMIA – toxins liberated by bacteria enters the blood stream to cause disease - example: diphtheria SAPREMIA – saprophytic bacteria may grow in dead tissues and produce poison which might be absorbed by the body K. L. Terminal – chronic wasting diseases Sporadic – occurring occasionally in a community Endemic – constantly present in a community Epidemic – disease attacking a large number of people in the community in a short time SPREAD OF INFECTION DIRECT CONTACT - droplet infection, placental transmission, bodily contacts [STD’s, blood transfusions from person to person in close association] INDIRECT CONTACT - spread indirectly using conveyers like milk, food, water, air, contaminated hands, inanimate objects [formites], filth, insects [mechanically or biologically (insect bites)]
