Page | 1 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman 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 MICROBIOLOGY microscopy, staining procedures, laboratory procedures, culture techniques People who Contributed to the Discovery of Microbiology A. Anthony Van Leeuwenhoek st - 1 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 Page | 2 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman 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] Phototrophic Bacteria 1. – produce own food – photosynthesis: green pigment - chlorophyll Gliding Bacteria 2. – flagella / cilia Sheathed Bacteria 3. – encloses organism : facultitively anaerobic a. Escherichia rods b. Salmonella c. Shigella d. Klebsiella e. Proteus Budding or Appendaged 4. – guides through budding [maturing] Spirochetes 5. Spiral and Curved 6. Gram-Negative Aerobic Rods and Cocci 7. a. Pseudomonas b. Azotobacter c. Rhizobium d. Halobacter e. Brucella f. Bordetella g. Francisella Gram-Negative Facultatively Anaerobic 8. 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 9. a. Bacteriodes b. Fusobacterium Gram-Negative Cocci and Coccobacilli 10. [aerobes] a. Neisseria b. Ecolli Gram-Negative Anaerobic Cocci 11. Gram-Negative Chemolithotrophic Bacteria 12. a. Nitrobacter b. Nitosomonas Methane-Producing 13. Gram-Positive Cocci 14. a. Staphylococcus b. Streptococcus c. Sarcina Endospore Forming Rods and Cocci 15. a. Bacillus Clostridium – Sporosarcina [rod shaped bacteria] - produce spore Gram-Positive 16. a. Lactobacilli Page | 3 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman Actinomycetes and related organisms 17. a. Coryneloacterium b. Actinomyces c. Breribacterium d. Mycobacterium e. Sterptomyces Ricketisias 18. – ricketisms Microplasmas 19. – 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 nonpathogenic bacteria ḯ PATHOGENICITY - 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 – clostridium petringens increases the virulence of organisms – gives the organisms its specific – immunologic nature Gram (+) positive capsule formers – 4. METACHROMATIC GRANULES enzymatically active – reserves of inorganic phosphates stored as – polymerized metaphosphate (volutin) Page | 4 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman may be arranged or located irregularly in the – bacterial cells � MYCOBACTERIUM TUBERCULOSIS 5. NUCLEUS contains the genetic codes that is pass from – generation to the next governing force for the bacterial cell in all – its vital activist 6. – – – – 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. 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 8. 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 Page | 5 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman 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 ● 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 - 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 development - 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 ✔ Light requirements: Red/Yellow – little bactericidal effect Green – less killing action Violet Ultraviolet Highly destructive to bacteria Blue Page | 6 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman 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. Bacterial Digestion - Hydrolases - Hydrolysis – addition to H20 2. Absorption - diffusion - active transport – physiologic pumps 3. Oxidation - preparing molecules for a possible bonding *oxidases / dehydrogenases / coenzymes cytochrome system *transfer to electrons 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 Medically Related Activities: A. Toxin Production – toxigenicity – toxicity – potency of toxins 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 Page | 7 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman Harmful metabolic products 1. Hemolysing – cause lysis / break up / destruction of RBC a. Filterable b. 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 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 Stapco aureus (gold) Pseudonas aeruginosa (blue-green) Halobacterium halobium (red) Serratia marcescens (red) 2. Heat production – example: heating of damp hay 3. Light production – biolumineneace : bacteria that live in water (salt) : light producers on non-pathogenic 4. 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 ● 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 1. ♋ 2. Skin staphylococci or fungi Respiratory Apparatus Page | 8 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman ♋ pulmonary tuberculosis or pneumonia or influenza ♋ viruses of measles or smallpox and German measles 3. Alimentary tract ♋ dysentery bacilli or cholera vibrios or amoebas of dysentery ♋ most often contacted thru food and drinks 4. Genitourinary system ♋ STD’s [gonorrhea or syphilis] 5. Placenta ♋ spirochete of syphilis or virus of smallpox 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 ° 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 1. FECES – salmonella, vibrio cholera, amoeba, shigella, viruses of poliomyelitis and type A hepatitis 2. URINE – pyelonephritis, TB of genitourinary tract and undulant fever 3. 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 5. BLOOD – protozoa of malaria, bacteria of tularemia, ricketisias of typhoid fever, virus of yellow fever 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 Page | 9 Twitter: @nursehooman Facebook: facebook.com/nurse.hooman 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 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 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 K. TOXEMIA – toxins liberated by bacteria enters the blood stream to cause disease - example: diphtheria L. SAPREMIA – saprophytic bacteria may grow in dead tissues and produce poison which might be absorbed by the body ⮚ 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 ▪ 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)]
