Microbiology - Exam 4 - Chapters 21, 22, & 23
True or False: Gastritis and gastric ulcers result from stress and eating spicy food.
False
True or False: It is healthier to have 10 species of bacteria colonizing the gastrointestinal tract than 100 species.
False
True or False: The lower respiratory tract is sterile.
False
True or False: The oral cavity is free of microorganisms.
False
True or False: The stomach and esophagus are free of microorganisms.
False
True or False: The vaccine against influenza provides lifelong protection.
False
True or False: The vaccine against pertussis provides lifelong protection.
False
True or False: There is an effective vaccine available for the common cold.
False
True or False: IgG is a protective antibody found in the gastrointestinal system.
False (IgA would make it True)
_____ and _____ have a much higher fatality rate over shorter duration.
MDR-TB and XDR-TB
Identify the distinctive structure that forms with diphtheria infections that can obstruct breathing.
Pseudomembrane forms on the tonsils or pharynx that can completely block respiration.
True or False: 1/3 of the world's population is infected with TB.
True
True or False: Ground beef is more dangerous than steaks or other cuts of meat for transmission of E. coli O157:H7.
True
True or False: In order for disease to result, an individual has to ingest a high number of Salmonella.
True
True or False: Organisms considered "normal biota" in the respiratory tract can cause serious disease.
True
True or False: Sinusitis, otitis media, and pharyngitis can all be sequelae of the common cold.
True
True or False: The accessory organs are free of microorganisms.
True
True or False: The mouth is ons of the eight sections of the gastrointestinal system.
True
True or False: There is an effective vaccine available for diphtheria.
True
True or False: Tooth decay is the most common infectious disease of human beings.
True
True or False: Yeasts such as Candida are considered part of the normal biota of mucosal surfaces of the upper respiratory tract.
True
Saliva contains _____ and _____, which are both antibacterial.
lysozyme and lactoferrin
Normal biota performs the important role of _____ _____ in the upper respiratory tract.
microbial antagonism
Chronic otitis media is considered to be a _____ infection.
mixture / biofilm
Mycobacterium tuberculosis & mycobacterium avium complex (MAC) are possible causative agents for _____
tuberculosis
Identify the main characteristics of Helicobacter pylori.
* Gram negative *curved rods with flagella * produces urease to buffer stomach acid
Explain how the discovery of Helicobacter pylori has changed how gastric ulcers are treated.
* Now treated with antibiotics because it's a bacterial infection (clarithromycin) * Clarithromycin is resistant to gastric acid and penetrates in high concentrations into gastric tissue and mucus and shows excellent antimicrobial activity against H. pylori.
Discuss the reason for the increase of pertussis cases over the past three decades.
* Vaccine does not provide lifelong protection. 1. Immunity wanes a few years after childhood 2. Increasing incidence in adult patients 3. Disease can be passed to infants who are yet fully immunized.
Identify what regions of the body become inflamed; related to digestive and other (mumps)
* corroded salvatory glands * inflammation of the salivary glands producing gopherlike swelling of cheeks
Natural defenses present in the gastrointestinal tract:
* heavy load of microorganisms * layer of mucus * secretory IgA * peristalsis (keeps microbes moving) * saliva (lysozyme & lactoferrin (binds to iron)) * stomach (low pH) acid + bile * GALT (gut associated lymphoid tissue)
Functions of the normal gut biota:
* protective function * teach the immune system to react properly to microbial antigens * aid digestion & provide nutrients * a diverse gut microbiome is associated with health
Identify the serious complications that can occur if a streptococcal infection is not treated.
1. Scarlet fever 2. Rheumatic fever 3. Glomerulonephritis
List and describe three sequelae of streptococcal pharyngitis.
1. Scarlet fever - caused by stains producing Erythrogenic toxin. 2. Rheumatic fever - damage to heart valves due to cross reactivity of antibodies to the M protein. 3. Glomerulonephritis - antigen-antibody complexes caught in the kidneys resulting in damage
Identify 2 bacteria that can cause dangerous pharyngitis cases.
1. Streptococcus pyogenes 2. Corynebacterium diptheriae
Nonbacterial causes of acute diarrhea
1. cryptosporidum 2. rotavirus 3. norovirus (most common of food borne illness in U.S.)
List three important causes of serious community-acquired pneumonia.
1. old age 2. season 3. underlying viral respiratory disease 4. diabetes 5. chronic abuse of alcohol or narcotics
Bacterial causes of acute diarrhea
1. salmonella 2. shigella 3. shiga toxin-producing E. coli 4. Other E. coli 5. campylobacter (most common in the U.S.) 6. clostridioides difficle 7. vibrio cholera 8. non-cholera vibrio species
Explain why someone would maybe think mump infections could cause sterility in males.
20%-30% of young adult males, the virus localizes in the epididymis and testes, but does not cause sterility
_____ _____ refers to the virus's ability to constantly mutate its glycoproteins. These glycoproteins which are on the viral envelope determine which host the virus can bind to and also lower the effectiveness of the host's immune response.
Antigenic drift
_____ _____ occurs when different genes or strands within the genes of the genome of the virus switch with a gene from a different strain of the virus. This generally occurs when two strains of the virus infect the same host, then the packaging step can switch which gene belongs to which host. This switching mechanism is very beneficial for the virus as it makes it a very difficult target for vaccines or drugs from a human perspective.
Antigenic shift
_____ _____ is the most common bacterial cause of diarrhea in the U.S.
Campylobacter
Identify the genus of yeast that are normal biota.
Candida
Whooping cough phases: Bacteria in the respiratory tract causes cold symptoms
Catarrhal phase
Identify the features of Shigella infections.
Gram-negative, straight
Identify the virulence factors that leads to the "rice-water-stool" seen with Vibrio cholera infections.
Cholera toxin (CT)
Causative Organism: approximately 200 viruses (rhinoviruses (most common), adenoviruses, and coronaviruses) Most Common Mode of Transmission: Indirect contact, droplet contact Virulence Factors: attachment proteins; most symptoms induced by host response Culture / Diagnosis: not necessary Prevention: hygiene practices Treatment: for symptoms only Epidemiological Features: highest incidence among preschool & elementary school children, with average of 3-8 colds per year; adults & adolescents: 2-4 colds per year
Common Cold
Whooping cough phase: Bacteria are decreasing, but ciliated epithelia have been damaged, requiring weeks to months of recovery.
Convalescent phase
Identify the most common infectious disease of humans.
Dental Caries (AKA cavities)
Explain the connect between carbohydrate consumption and acid production by the bacteria.
Dissolution of the tooth surface due to the metabolic action of bacteria results in minor to complete disruption of enamel streptococcus mutans and S. sobrinus are the main causes incidence varies according to carbohydrate consumption, oral hygiene, and genetic factors.
Influenza A, B, and C viruses are causative agents for _____
Influenza
Explain ID50 as it relates to Salmonella infections.
It has a high ID50-infectious dose for 50% of the population.
Identify the region of the GI tract that has the largest population of normal biota.
Large Intestine
The gastrointestinal tract; Eight main segments:
Mouth Pharynx Esophagus Stomach Small Intestine Large Intestine Rectum Anus
Causative Organism: Haemophilus influenzae Most Common Mode of Transmission: Endogenous (follows upper respiratory tract infection) **infection gets to the middle ear by way of eustachian (auditory) tubes Virulence Factors: capsule, fimbriae Culture / Diagnosis: None Prevention: Hib vaccine (only effective for one subtype) Treatment: wait for resolution; if needed, amoxicillin (higher rates of resistance) or amoxicillin + clavulanate or cefuroxime; antibiotic usage recommended for babies less than 6 months old Distinctive Features: N/A Epidemiological Features: 30% of cases in the U.S.
Otitis media
Causative Organism: Streptococcus pneumoniae Most Common Mode of Transmission: Endogenous (may follow upper respiratory tract infection by S. pneumoniae or other microorganisms) **infection gets to the middle ear by way of eustachian (auditory) tubes Virulence Factors: capsule, hemolysin Culture / Diagnosis: usually relies on clinical symptoms and failure to resolve within 72 hours. Prevention: pneumococcal conjugate vaccine (PCV13) Treatment: wait for resolution; if needed, amoxicillin (higher rates of resistance) or amoxicillin + clavulanate or cefuroxime; antibiotic usage recommended for babies less than 6 months old Distinctive Features: N/A Epidemiological Features: 30% of cases in the U.S.
Otitis media
Causative Organism: other bacteria/viruses/fungi Most Common Mode of Transmission: Endogenous **infection gets to the middle ear by way of eustachian (auditory) tubes Culture / Diagnosis: None Prevention: None Treatment: wait for resolution; if needed, a broad-spectrum antibiotic (azithromycin) might be used in absence of etiologic diagnosis.... (broad-spectrum bc the infecting agent is likely unknown) Distinctive Features: suspect if fully vaccinated against other two
Otitis media
Whooping cough phases: Uncontrollable coughing accompanied by a "whoop" sound. Can result in broken blood vessels in the eyes, vomiting, or even hemorrhages in the brain.
Paroxysmal phase
Explain the relationship between the BCG vaccine and the tuberculin skin test.
People who were previously vaccinated with BCG may receive a TB skin test to test for TB infection. Vaccination with BCG may cause a false positive reaction to a TB skin test. A positive reaction to a TB skin test may be due to the BCG vaccine itself or due to infection with TB bacteria.
Causative Organism: Fusobacterium necrophorum Most Common Mode of Transmission: usually endogenous Virulence Factors: invasiveness, endotoxin Culture / Diagnosis: culture anaerobically; CT scan for abscess Prevention: ? Treatment: penicillin Distinctive Features: can lead to Lemierre's syndrome Epidemiological Features: causes up to 15% of acute pharyngitis in teens/young adults
Pharyngitis
Causative Organism: Streptococcus pyogenes Most Common Mode of Transmission: droplet or direct contact Virulence Factors: LTA, M protein, hyaluronic acid capsule, SLS and SLO, superantigens, induction of autoimmunity Culture / Diagnosis: beta-hemolytic on blood agar, sensitive to bacitracin, rapid antigen tests Prevention: hygiene practices Treatment: penicillin, cephalexin in penicillin-allergic Distinctive Features: generally more severe than viral pharyngitis Epidemiological Features: U.S.: 10% to 20% of all cases of pharyngitis
Pharyngitis
Causative Organism: Viruses Most Common Mode of Transmission: all forms of contact Culture / Diagnosis: goal is to rule out S. pyogenes (and F. necrophorum); further diagnosis usually not performed Prevention: hygiene practices Treatment: symptom relief only Distinctive Features: hoarseness frequently accompanies viral pharyngitis Epidemiological Features: ubiquitous; responsible for 40% to 60% of all pharyngitis
Pharyngitis
Explain why so many diverse microorganisms can cause the condition of pneumonia.
Pneumonia is an inflammatory condition of the lung in which fluid fills the alveoli. * Can be caused by a wide variety of microorganisms * Must be able to avoid phagocytosis *Or avoid killed once inside macrophages
Respiratory syncytial virus and Respiratory picornavirus are causative agents for _____
RSV
The gastrointestinal tract; Four accessory organs:
Salivary Glands (in mouth) Liver (makes bile) Gallbladder (stores bile) Pancreas ** Accessory organisms are free of resident microorganisms.
Identify the premise behind using fecal transplants as a treatment for Clostridium difficile infections.
Samples of stool are taken from individuals who live in the same household as the patient because they are thought to have the same biota. Introducing healthy biota back into the patient will help the gut re-establish their healthy biota.
Identify the toxin that distinguishes E. coli O157:H7 from other stains of E. coli.
Shiga toxin
Causative Organism: Various bacteria, often mixed infection Most Common Mode of Transmission: endogenous (most common) (opportunism) Culture / Diagnosis: culture not usually performed; diagnosis based on clinical presentation, occasionally x-rays or other imaging technique used Prevention: N/A Treatment: recommendation is for no antibiotics unless it remains unresolved for some weeks Distinctive Features: viral & bacterial much more common than fungal Epidemiological Features: United States: affects 1 of 7 adults; between 12 and 30 million diagnoses per year
Sinusitis (Bacterial)
Causative Organism: various fungi Most Common Mode of Transmission: introduction by trauma or opportunistic overgrowth Culture / Diagnosis: culture not usually performed; diagnosis based on clinical presentation, occasionally x-rays or other imaging technique used Prevention: N/A Treatment: physical removal of fungus; in severe cases, antifungals used Distinctive Features: suspect in immunocompromised patients Epidemiological Features: Fungal sinusitis varies with geography; in the U.S.: more common in SE & SW; internationally: more common in India, North Africa, Middle East
Sinusitis (Fungal)
Causative Organism: Viruses Most Common Mode of Transmission: direct contact, indirect contact Culture / Diagnosis: culture not usually performed; diagnosis based on clinical presentation Prevention: hygiene practices Treatment: none Distinctive Features: viral & bacterial much more common than fungal Epidemiological Features: commonly follows the common cold
Sinusitis (Viral)
Identify what causes scarlet fever.
Stains producing erythrogenic toxins.
_____ _____ is the bacterium responsible for 40% of all cases of community-acquired pneumonia.
Streptococcus pneumoniae
List the main genera of normal biota presently known to occupy the respiratory tract.
Streptococcus pyogenes Haemophilus influenzae Streptococcus pneumoniae Neisseria meningitidis Staphylococcus aureus
Identify the type of virulence factor that makes Streptococcus pyogenes and Corynebacterium diptheriae so dangerous.
They are both exotoxins.
Epidemiological patterns vary with the living conditions of a community or area of the world. _______ is an infection of poverty.: Inadequate nutrition Debilitation of the immune system Poor access to medical care Lung damage Genetics
Tuberculosis (TB)
Nasal Hairs, Ciliated Epithelium of Trachea & Bronchi, Mucus, Coughing, Sneezing, and Swallowing are _____ defenses in the respiratory tract.
anatomical
Rhino viruses, Streptococcus pneumonaie, and mycoplasma pneumonaie are possible causative agents for ______
community-acquired pneumonia
Antimicrobial ________, ________and ________ in the lungs are chemical defenses against invading pathogens.
complement, antimicrobial peptides, secretory IgA
Streptococcus mutans & S. sobrinus (main causes) and a polymicrobial mixture of acid-producing bacteria are causative agents for __________ ___________ in the GI tract.
dental caries
Antigenic _____ refers to minor changes in viral antigens and antigenic _____ is the result of gene swapping between different strains of virus.
drift; shift
Identify the features of Clostridium difficile infections.
enterotoxins A and B which cause necrosis in all of the intestine. They present as gram-positive, endospore forming rods found as normal biota of the intestine.
In _____ tuberculosis, the lymph nodes, kidneys, long bones, and other organs can become involved.
extra-pulmonary
Helicobacter pylori, Vibrio cholera, Staphyloccocus aureus, Escherichia coli O157:H7 are causative agents for _____ _____ in the GI tract.
gastric ulcers
Respiratory syncytial virus infects the respiratory tract and produces ______ _____ _____.
giant multinucleated cells
Hantavirus is a possible causative agent for _____
hantavirus pulmonary syndrome
Patients requiring mechanical ventilation or who have tracheostomy tubes are more susceptible to _____ associated pneumonia.
health care
Pseudomonas aeruginosa Acinetobacter baumannii Klebsiella pneumoniae Enterobacter Escherichia coli Staphylococcus aureus (usually MRSA) These are all possible causative agents for ____
healthcare-associated pneumonia
Explain how syncytia formation helps the virus evade our immune system.
it can invade other organs
Alveoli can be found in the _____ respiratory tract.
lower
The trachea, within the lungs, bronchi, bronchioles, and alveoli are part of the _____ ______ tract.
lower respiratory
Mumps virus (genus paramyxovirus) is the causative agent for _____ in the GI tract.
mumps
Identify the causative agent of mumps.
mumps virus (genus paramyxovirus)
Two anatomical methods for trapping bacteria in the respiratory tract are _____ & _____.
nasal hairs; mucus
Respiratory syncytial virus is most serious in _____ babies.
newborn
Identify the most immediate and important treatment needed to prevent death in cholera victims.
oral rehydration therapy
Polymicrobial community including some or all of tanneralla forsythia Aggregatibacter actinomycetemcomitans, prophymonas gingivalis, others are causative agents for _____ _____ in the GI tract.
periodontal diseases
With _____ _____ _____, mortality is highest among premature infants, those with congenital disease or immunodeficiency.
respiratory syncytial virus (RSV)
The four accessory organs are _____, _____, _____, and _____.
salivary glands, liver, gallbladder, pancreas
The following are _____ & _____ defenses. 1. Complement action in the lungs 2. Increased levels of cytokines & antimicrobial peptides 3. Macrophages in the alveoli of the lungs & the clusters of lymphoid tissue in the tonsils 4. Secretory IgA
second; third
The larynx is part of the _____ respiratory tract.
upper
The mouth, nose, nasal cavity, sinuses, throat (pharynx), epiglottis, larynx are part of the _____ _____ tract.
upper respiratory
Bordetella pertussis and Bordetella parapertussis are causative agents for _____
whooping cough
The chain of transmission of the causative agent of hantavirus pulmonary syndrome.
•Airborne virus via dust contaminated with urine, feces, or saliva of infected rodents •Deer mice or other rodents harbor one or more of the multiple strains of hantavirus