Final Exam Review PDF

Final Exam Review Andrei Kouranov Beta hemolytic staphylococci & streptococci examples Another test for Strep infection: Rapid test for the presence of Streptolysin O Streptococcus pyogenes Streptoco...

Final Exam Review Andrei Kouranov Beta hemolytic staphylococci & streptococci examples Another test for Strep infection: Rapid test for the presence of Streptolysin O Streptococcus pyogenes Streptococcus agalactiae Staphylococcus aureus These pathogens produce enzyme beta-hemolyse which causes hemolysis of erythrocytes Blood agar test Staphylococcus aureus Streptococcal infection may cause pharyngitis. If untreated pharyngitis may transition to glomerulonephritis (kidney) or rheumatic fever (heart) Staphylococcus epidermisis Naked & Enveloped Viruses Copyright © McGraw-Hill Education. Permission required for reproduction or display. Spike Capsid Nucleic Nucleic acid acid Capsid Envelope Spike (a) Naked Virus (b) Enveloped Virus Other Parasitic Particles: Viroids and Prions Characteristics of Prions Proteinaceous infectious agents Cellular P r P Made by all mammals Normal, functional structure has α-helices Prion P r P Disease-causing form has β-pleated sheets Prion P r P causes cellular P r P to refold into prion P r P Skin Infections Fungal Skin Infections Recall that fungi are decomposers or saprophytes (detritivores) ; they gain their nutrition from dead and decaying tissues. Since skin has the superficial layer of stratum corneum, this is a layer of dead skin cells. Therefore, fungi are frequently seen in otherwise healthy individuals affecting the superficial skin. Pityriasis versicolor or tinea versicolor Caused by Malassezia furfur fungus. Has characteristic of more or less pigmentation of skin (hyperpigmented or hypopigmented skin); hence the name VERSIcolor because it has versatile coloration. GastroInfectious Diseases Affecting the Gastrointestinal Tract Norovirus and rotavirus are different viruses that cause stomach problems, like nausea, vomiting, and diarrhea. Norovirus is more common in adults, while rotavirus tends to affect infants and young children. There is a vaccine to prevent rotavirus, but there is no vaccine to prevent norovirus. Causative agents of food poisoning Bacillus cereus Traveler’s diarrhea: various enteric bacteria including E.coli, Salmonella, Shigella Traveler's diarrhea is a digestive tract disorder that commonly causes loose stools and abdominal cramps. It's caused by eating contaminated food or drinking contaminated water. Fortunately, traveler's diarrhea usually isn't serious in most people — it's just unpleasant. Escherichia coli 0157-H7 – hallmark symptom bloody diarrhea Produces shiga toxin: Shiga toxin seems to be responsible for more serious damage to the intestine and systemic effects. Shiga toxins act to inhibit protein synthesis within target cells by a mechanism similar to that of ricin Helicobacter pylori: causative agent of stomach ulcers & cancer  Infectious Diseases Affecting the Cardiovascular and Lymphatic Systems Septicemia Occurs when organisms are actively multiplying in the blood: Many different bacteria and viruses can cause this condition. MRSA is a common cause 10% are caused by fungal infections Signs and Symptoms: – Fever is a prominent feature. Patient is very ill and may have an altered mental state, shaking, chills, and gastrointestinal symptoms. – Increased breathing rate accompanied by respiratory alkalosis – Low blood pressure is a hallmark of this condition  Borrelia burgdorferi – gram-negative Systemic blood infections caused by Streptococcus mutans, spirochete causes Lyme disease Staphylococcus aureus can progress to endocarditis Spread by ticks Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans Examples of post infection sequela: Post-streptococcal glomerulonephritis (PSGN) is an immunologically-mediated sequela of pharyngitis or skin infections caused by nephritogenic strains of Streptococcus pyogenes. Chagas Disease caused by Trypanosoma cruzi (protozoan) Symptoms: Swelling at the infection site. Fever. Fatigue. Malaise Body aches. Headache. Loss of appetite. Present in the South-East of the US Infected people may develop fatal congestive heart 10-20 year after the onset of the initial symptoms HIV Infection and AIDS Signs and Symptoms: – A spectrum of clinical signs and symptoms is associated with human immunodeficiency virus – Symptoms of HIV are directly tied to two things: The levels of virus in the blood The levels of T cells in the blood – Initial symptoms: Fatigue, diarrhea, weight loss, and neurological changes Opportunistic infections or cancers HIV Infection and AIDS (cont’d) Causative Agent: HIV is a retrovirus in the genus Lentivirus: Retroviruses have the potential to cause cancer. They produce often fatal diseases and are capable of altering the host’s DNA. Contain reverse transcriptase (RT): Catalyzes the replication of double-stranded DNA from single- stranded RNA Retroviruses can permanently integrate viral genes into the host genome that is passed on to progeny cells. Infectious Diseases Affecting the Respiratory System Influenza Causative Agents: Influenza A, B and C viruses Orthomyxoviridae Lipoprotein envelope Glycoprotein spikes Hemagglutinin (H) Neuraminidase (N) Ion channels ssRNA genome 10 genes on 8 RNA strands Influenza (cont’d) Pathogenesis and Virulence Factors: – Virus binds ciliated cells of the respiratory mucosa – Severe inflammation, irritation in lungs due to “cytokine storm” – Hemagglutinin (H) binding to host cell receptors – Neuraminidase (N) breaks down mucous of the respiratory tract, assists in viral budding/release – 2009 H1N1 “Swine flu”: variants bound lower, more efficiently, in respiratory tract causing massive cytokine storm; not all patients had a fever, many patients had gastrointestinal distress, or developed multiorgan system failure Viral receptors that bind to host mucosal cell surfaces Bacterial Diseases of the Lower Respiratory System (11 of 19) Tuberculosis The leading disease killer in the world Incidence has declined in the industrialized world Signs and symptoms Initially limited to minor cough and mild fever Symptoms are not always apparent Pathogen and virulence factors Caused by Mycobacterium tuberculosis Presence of mycolic acid gives bacteria unique features Slow growth Protection from phagocytic lysis by macrophages Intracellular growth Resistance to many antimicrobial drugs Mycoplasma pneumoniae: A very small bacterium without the cell wall; causative agent of walking pneumonia. Sometimes called ventilator-associated pneumonia Bacterial membrane mimics cell surface composition. This characteristics makes it very resistant to immune system Infectious Diseases Affecting the Genitourinary System Urinary Tract Infections Causative Agents: We must distinguish between UTIs that are acquired in health care facilities and those acquired outside the health care setting: Catheter-associated UTIs (CA-UTIs) 95% of UTIs are caused by normal biota of the gastrointestinal tract: Escherichia coli is responsible for 80% of these. Staphylococcus saprophyticus and Enterococcus  Syphilis: Genital Ulcer Disease Causative Agent: Treponema pallidum: Spirochete: thin, regularly coiled cell Gram-negative cell wall Strict parasite with complex growth requirements that necessitate cultivating it in living host cells Syphilis Marked by clinical stages designated as: - Primary syphilis - Secondary syphilis - Tertiary syphilis Also has latent periods of varying duration during which it is quiescent Spirochete appears in the lesions and blood cultures during the primary and secondary stages, and is transmissible at these times: - Also transmissible during the early latency period between secondary and tertiary syphilis - Largely nontransmissible during the “late latent” and tertiary stages Match the animal association with the disease. Answers Match the disease/organism with the organism type. are used only once, not all answers are used. S. Pneumoniae gram positive bacteria Mosquito malaria Hepatitis virus Cow brucellosis Trichomoniasis protozoan Human mononucleosis E. Vermicularis multicellular parasite Rabies bat T. pallidum gram negative bacteria Tularemia rabbit Match the disease with the sign or symptom description Match the disease with its description. histoplasmosis fungal pneumonia Pertussis barking cough Schistosomiasis itchy skin lesion Ebola internal hemorrhage pertussis barking cough Mumps salivary gland swelling mumps parotid gland swelling Cholera dysentery Match the sign/symptom with the disease. German measles congenital malformations saber shin tibia congenital syphilis Chancre primary syphilis Jaundice viral hepatitis abdominal cramping food poisoning extreme itching of vagina candidias Match the disease with how it is spread. Use each Match the disease with the description of the type of person most likely to answer only once. get that disease or most associated with the disease. Farmer anthrax Shigellosis fecal-oral Athlete tinea pedis Mononucleosis salivary secretions premature baby respiratory syncytial virus Tuberculosis respiratory droplets AIDS patient fungal pneumonia hepatitis B blood products hospital patient pseudomembranous colitis Botulism honey Match the disease with the hallmark characteristic. Match the sign or symptom with the organism. slapped cheek fifths disease bloody diarrhea E. coli 0157-H7 bulls-eye rash lyme disease bloody sputum M. tuberculosis muscle aches influenza Pseudomembrane C. difficile purulent exudate from male urethra gonorrhea rice water stool V. cholera grossly enlarged lymph node plague Chancre T. pallidum Some terms: agammaglobulinemia primary immunodeficiency atopy type I hypersensitivity: IgE mediated response AIDS secondary immunodeficiency binomial nomenclature method of identifying cellular organisms Lancefield classification system for Streptococcus organisms prodrome non-specific signs and symptoms incubation post exposure interval Convalescence disease is gone acute worst point of illness or disease state sequela residual effects of illness