microbiology chapters 19-22
Leprosy
(Hansen's disease) Disease caused by infection with Mycobacterium leprae that produces either a nonprogressive tuberculoid form or a progressive lepromatous form that destroys tissues, including facial features, digits, and other structures
Staphylokinase
(produced by S. aureus) dissolves fibrin threads in blood clots, allowing S. aureus to free itself from clots. Thus, Staphylococcus can escape the immune system by enclosing itself in a fibrin clot (via coagulase), and then, when space and nutrients become limiting, it can digest its way out of the clot with staphylokinase and spread to new locations.
Chloramphenicol
-Blocks peptidyltransferase at 50S ribosomal subunit. -Bacteriostatic. -Use: Meningitis (Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae) and Rocky Mountain spotted fever (Rickettsia rickettsii). Limited use owing to toxicities but often still used in developing countries because of low cost. -Toxicity: anemia (dose dependent), aplastic anemia (dose independent), gray baby syndrome (in premature infants because they lack liver UDP-glucuronyl transferase). -Resistance: plasmid-encoded acetyltransferase inactivates the drug.
Ehrlichia chaffeensis
-Ehrlichiosis -Ambylomma (Lone Star tick)
Chlamydophila psittaci
-Psittacosis -Parrots, other birds
What is the difference between the cell walls of Gram-positive bacteria and those of Gram-negative bacteria?
A Gram-positive bacterium has a thick layer of peptidoglycan and lacks an outer membrane.
blackhead
A blackhead is formed when a plug of dead and dying bacteria blocks the gland's pore
Enterobacteriaceaea have an outer membrane that contains lipopolysaccharide composed of three antigenic components:
A core polysaccharide, shared by all of the enteric bacteria and called common antigen. Lipid A, which, when released in a patient's blood, can trigger fever, vasodilation, inflammation, shock, and DIC Because of the presence of lipid A, most of the enteric bacteria can cause serious disease and death.
Who would most likely develop a C. difficile infection?
A patient that has been taking broad-spectrum antimicrobial drugs
Tuberculosis
A respiratory disease caused by infection with Mycobacterium tuberculosis; its disseminated form can result in wasting away of the body and death
shigellosis
A severe form of dysentery caused by any of four species of Shigella
Gonorrhea
A sexually transmitted disease caused by infection with Neisseria gonorrhoeae
strep throat
A sore throat caused by streptococci, commonly known as "strep throat," is a kind of pharyngitis inflammation of the pharynx—that is accompanied by fever, malaise, and headache. The back of the pharynx typically appears red, with swollen lymph nodes and purulent abscesses covering the tonsils
Cytolytic toxins
Alpha, beta, gamma, and delta toxins are proteins, coded by chromosomal genes, that disrupt the cytoplasmic membranes of a variety of cells, including leukocytes (white blood cells)
Which developmental stage of Ehrlichia and of Anaplasma (which cause ehrlichiosis and anaplasmosis respectively) is infective? (Which stage enters the body?)
An elementary body
In the case of gastrointestinal disease, how can an intoxication be distinguished from an infection?
An intoxication is usually apparent shortly after ingestion, while an infection takes longer.
Why is treatment of inhalational anthrax with antimicrobial drugs often not successful unless treatment starts very early?
Anthrax toxin would have been released already and it is not affected by antimicrobial drugs.
What type of flagella do spirochetes have?
Axial filaments composed of endoflagella
The endospore-forming genera
Bacillus and Clostridium.
Cellulitis
Bacteria, often GAS, entering breaks in the skin may invade deeper layers of the skin to cause red, painful, localized inflammation more common in the lower extremities, particularly in the immunocompromised, the obese, and diabetics who do not manage their condition well.
anaerobic opportunists are
Bacteroides and Prevotella.
Bartonella and Brucella in the class Alphaproteobacteria,
Bartonella a genus of aerobic bacilli are found in animals, but they are known to cause disease only in humans. Brucella a genus of small, nonmotile, aerobic coccobacilli that lack capsules but survive phagocytosis by preventing lysosomes from fusing with phagosomes containing the bacterium.
Why are women more likely to contract urinary tract infections than men?
Because the female urethra is shorter and the entrance is close to the anus
Protein A
Binds Fc region of IgG. Prevents opsonization and phagocytosis. Expressed by S. aureus.
eschar
Black, swollen, crusty, painless skin ulcer of anthrax
Bordetella and Burkholderia Betaproteobacteria
Bordetella pertussis: small, aerobic, non motile, Gram-negative coccobacillus that is responsible for the disease pertussis,commonly called whooping cough. Burkholderia cepacia: soil-dwelling, aerobic, and flagellated decomposes a broad range of organic molecules, making it a likely bacterium to assist in the cleanup of contaminated environmental sites.
Botulism effects
Botulism toxin blocks the fusion of the vesicles with the neuron's cytoplasmic membrane, thereby preventing secretion of the neurotransmitter into the synaptic cleft as a result, the muscle cell does not contract. prevent muscular contraction, resulting in a flaccid paralysis.
How does streptokinase facilitate virulence of Streptococcus pyogenes?
By breaking down blood clots, facilitating the spread of S. pyogenes through infected and damaged tissues
The most common pathogenic clostridia are
C. difficile C. botulinum C. tetani C. perfringens
Which of the Clostridium species causes a disease that is vaccine-preventable?
C. tetani
Chlamydophila pneumoniae
Causes pneumonia, bronchitis, and sinusitis
Orientia tsutsugamushi
Causes scrub typhus. Transmitted by mites. disease endemic to eastern Asia, Australia, and India.
Staphylococci enzymes
Cell-free coagulase Hyaluronidase Staphylokinase Lipases b-lactamase
Which of the following is the cause of the STD known as lymphogranuloma venereum? Group of answer choices
Chlamydia trachomatis
Three chlamydias cause disease in humans.
Chlamydia trachomatis Chlamydophila pneumoniae Chlamydophila psittaci
gas gangrene
Clostridium perfringens rapidly reproducing bacteria can spread into the surrounding tissue, causing the death of muscle and connective tissue that is typically accompanied by the production of abundant, foul-smelling, gaseous, bacterial waste products
Opsonins
Coating proteins that promote phagocytosis: IgG and C3b
Bound coagulase
Converts fibrinogen fibrin molecules Fibrin clots hide the bacteria from phagocytic cells
Phaeohyphomycosis
Cutaneous and subcutaneous disease characterized by lesions that can spread internally; caused by traumatic introduction of ascomycetes into the skin
Various strains of Staphylococcus aureus also possess several toxins that contribute to their pathogenicity
Cytolytic toxins Exfoliative toxins Toxic shock syndrome (TSS) toxin Enterotoxins
Pasteurellaceae
Definition:Family of gammaproteobacteria, two genera of which—Pasteurella and Haemophilus—are pathogenic
Serological classification
Developed by Rebecca Lancefield (1895-1981), that divides streptococci into serotype groups based on the bacteria's antigens
Clostridium
Domain Bacteria, phylum Firmicutes, class "Clostridia," order Clostridiales, family Clostridiaceae Cell morphology and arrangement: Endospore-forming bacillus Gram reaction: Positive Virulence factors: Endospore, botulism toxins A-G Diseases caused: Foodborne botulism, infant botulism, and wound botulism Treatment for diseases: Repeated washing of intestinal tract to remove Clostridium, administration of antitoxin (antibodies against the toxins), antimicrobial drugs used for cases of infant botulism and wound botulism; damage to nerve endings irreversible Prevention of disease: Proper canning to kill endospores; refrigeration to prevent endospores from germinating; heating to 80°C for 20 minutes to destroy toxin; refrain from feeding honey to infants an anaerobic, Gram-positive, endospore-forming bacillus that is ubiquitous in soil, water, sewage, and the gastrointestinal tracts of animals and humans.
During a stay in the hospital, an accident victim develops symptoms of bacteremia. A blood sample shows the presence of Gram-positive cocci in pairs. Lab tests determine that the bacteria are nonhemolytic and bile salt tolerant. The bacteremia is likely due to
ENTEROCOCCUS
The skin lesions characteristic of cutaneous infections with Bacillus anthracis are
ESCHARS
botulism toxins
Each of the seven toxins is a quaternary protein composed of a single neurologically active polypeptide associated with one or more nontoxic polypeptides that prevent the inactivation of the toxin by stomach acids
Exfoliative toxins
Each of two distinct proteins causes the dissolution of epidermal desmosomes (intercellular bridge proteins that hold adjoining cytoplasmic membranes together), causing the patient's skin cells to separate from each other and slough off the body.
People living in the northeastern United States are more at risk for exposure to which of the following rickettsias?
Ehrlichia chaffeensis
What is the function of endospores?
Endospores are survival structures.
urease
Enzyme that changes urea into ammonia and carbon dioxide
Which of the following coliforms is the most common cause of non-nosocomial urinary tract infections
Escherichia coli
Hemolytic uremic syndrome is caused by
Escherichia coli O157:H7.
Most microbes that reside in the intestines are facultative or obligate anaerobes. Describe the growth of facultative anaerobes in the presence of and also in the absence of molecular oxygen.
Facultative anaerobes can grow without molecular oxygen, but grow faster in its presence.
pneumonic plague
Fever and severe respiratory distress caused by infection of the lungs with Yersinia pestis; fatal if untreated in nearly 100% of cases
Tertiary syphilis
Final phase of the sexually-transmitted disease caused by Treponema pallidum occurring years after the secondary phase and characterized by severe hyperimmune complications resulting in dementia, blindness, paralysis, heart failure, or rubbery, swollen lesions called gummas
h antigens
Flagellar antigens of bacteria
noninvasive disease
Food poisoning from the ingestion of enterotoxin-contaminated food The food must remain at room temperature or warmer for several hours for the bacteria to grow, reproduce, and secrete toxin. Warming or reheating inoculated food does not inactivate enterotoxins, which are heat stable, although heating does kill the bacteria
rickettsias
Four genera Rickettsia Orientia Ehrlichia Anaplasma are the main rickettsias that cause diseases in humans.
Which of the following genera contains the most virulent species?
Francisella
What clostridial disease can be treated with oxygen applied under pressure?
Gas gangrene
Proteus
Gram-negative, facultative anaerobe rod-shaped bacterium with a few polar flagella when cultured in broth but differentiates into an elongated cell that swarms by means of numerous peritrichous flagella when cultured on agar.
Group B Streptococcus: Streptococcus agalactiae
Gram-positive coccus has group-specific, polysaccharide cell wall antigens forms buttery colonies that are 2-3 mm in diameter have a small zone of beta-hemolysis after 24 hours of growth on blood agar it is bacitracin resistant forms capsules, antibodies target its capsular antigens, so the capsules don't provide the bacterium protection from the immune system. most pathogenic in newborns who have not yet formed type-specific antibodies normally colonize the lower gastrointestinal (GI), genital, and urinary tracts.
Propionibacteria
Gram-positive, anaerobic rods commonly found growing on the skin. they produce propionic acid as a by-product of the fermentation of carbohydrates. most commonly involved in infections of humans is Propionibacterium acnes which is the most common cause of acne
Enterococcus
Gram-positive, catalase-negative cocci so named because all enterococci are spherical and live in the intestinal tracts of animals. Enterococcus is unencapsulated, produces gas during fermentation of sugars, and is typically nonhemolytic Enterococci form short chains and pairs; they do not form capsules grow at temperatures up to 45°C, at pH as high as 9.6, and in 6.5% NaCl or 40% bile salt broths The two species that are significant pathogens of humans are E. faecalis and E. faecium
staphylococcus
Gram-positive, facultatively anaerobic prokaryotes spherical cells are typically clustered in grapelike arrangements non motile salt tolerant they are tolerant of desiccation, radiation, and heat (up to 60°C for 30 minutes) synthesizes catalase
Streptococcal Toxic Shock Syndrome
Group A streptococci can spread, albeit rarely, from an initial site of infection, particularly in patients infected with HIV or suffering with cancer, heart disease, pulmonary disease, or diabetes mellitus. Such spread leads to bacteremia and severe multisystem infections
Pasteurellaceae
Haemophilus, pasteurella G- bacilli
Infection with ________ may result in peptic ulcers and stomach cancer. Group of answer choices
Helicobacter pylori
What is the best way to prevent infection by Streptococcus pneumoniae?
Immunization
Elek test
Immunodiffusion assay used to detect the presence of diphtheria toxin in a fluid sample
How does the motility of Listeria monocytogenes in human cells differ from its motility in the environment?
In human cells, L. monocytogenes forms a "tail" from cell-derived actin filaments.
In people who develop tuberculosis, tubercles form in the lungs. What does the inside of a tubercle consist of?
Infected macrophages
Primary syphilis
Initial phase of the sexually-transmitted disease caused by Treponema pallidum characterized by a small, painless, red, hard lesion called a chancre
MDR-TB strains are resistant to which drugs at a minimum?
Isoniazid and rifampin
Actinomyces
It can become an opportunistic pathogen of the respiratory, gastrointestinal, urinary, and female genital tracts and the skin, and it sometimes causes dental caries (cavities).
What is the role of the capsule of Pseudomonas aeruginosa in patients with cystic fibrosis?
It facilitates formation of a biofilm and helps the bacterium evade phagocytosis.
What is the function of the type III secretion system in E. coli O157:H7
It introduces virulence proteins directly into host cells.
Which of the following statements about Bacillus anthracis is FALSE?
It is primarily a disease of humans.
Klebsiella
K. pneumoniae which causes pneumonia and may be involved in bacteremia, meningitis, wound infections, and UTIs. Pneumonia caused by K. pneumoniae often involves destruction of alveoli and the production of bloody sputum. Alcoholics and patients with compromised immunity are at greater risk of pulmonary disease because of their poor ability to clear aspirated oral secretions from their lower respiratory tracts.
Listeria monocytogenes
Listeria is a low G + C, Gram-positive, non-endospore-forming, rod-shaped bacterium with end-over-end, tumbling motility outside the body. It is found in soil, water, and animals, including insects. It enters the body through consumption of contaminated drink or food, typically deli meats, hot dogs, soft cheeses, and yogurt. tolerant of cold temperatures, so it can grow in refrigerated food antimicrobial drugs, primarily ampicillin, inhibit Listeria
Describe two structures in Streptococcus pyogenes that enable this organism to survive the body's defenses.
M protein. A membrane protein called M protein destabilizes complement, thereby interfering with opsonization and lysis. Hyaluronic acid capsule. Because hyaluronic acid is normally found in the body, white blood cells may ignore bacteria "camouflaged" by this type of capsule.
two important pathogenic mycoplasmas
M. pneumoniae: Ureaplasma: does hydrolyze urea to form ammonia.
mycobacterial diseases in humans are caused by two species
M. tuberculosis M. leprae which cause tuberculosis and leprosy,
How can members of the Enterobacteriaceae and Pasteurellaceae be distinguished from each other?
Members of Enterobacteriaceae are oxidase negative, while those of Pasteurellaceae are oxidase positive.
How is gonorrhea experienced differently in men and women?
Men experience painful urination and pus discharge, while women are often asymptomatic
The viridans streptococci, a group in the alpha-hemolytic streptococci, include members that inhabit which of the following areas in the human body?
Mouth and pharynx
Mycobacterium spp. have cell walls with mycolic acids. Which characteristics does the mycolic acid confer?
Mycolic acid protects Mycobacterium spp. from drying out.
What is the difference between Gram-positive bacteria and mycoplasmas?
Mycoplasmas do not have cell walls.
Nocardia
N. asteroides is an opportunistic bacterial pathogen that infects numerous sites, including the lungs, skin, and central nervous system. In the lungs, Nocardia causes pneumonia accompanied by signs and symptoms typical of pulmonary infections—cough, shortness of breath, and fever. Cutaneous infections may produce mycetoma, a painless, long-lasting infection characterized by swelling, pus production, and draining sores
Two species of Neisseria are pathogenic to humans
N. gonorrhoeae which causes gonorrhea, meningococcus, N. meningitidis which causes a type of meningitis.
The cerebrospinal fluid from a patient was obtained and a Gram stain revealed Gram-negative diplococci. Which of the following organisms is the patient likely infected with?
Neisseria meningitis
Considering the fact that Pseudomonas aeruginosa has so many virulence factors, why is it not a more common source of infection in the general public, rather than only an opportunistic pathogen?
P. aeruginosa cannot penetrate the skin and mucous membranes or evade the body's other defenses.P. aeruginosa cannot penetrate the skin and mucous membranes or evade the body's other defenses.
Ehrlichiosis and Anaplasmosis
PATHOGEN: Ehrlichia spp. and Anaplasma spp. SYMPTOMS: Flulike RESERVOIR: Deer MOT: Ixodes ticks TREATMENT: Tetracycline
Escherichia coli
Pathogenic strains of E. coli are named for the conditions they cause, such as enterohemorrhagic E. coli (EHEC, life-threatening bloody diarrhea), uropathogenic E. coli (UPEC, urinary tract infections), and enteroinvasive E. coli (EIEC, severe diarrhea with high fever). E. coli is responsible for a number of diseases, including septicemia, neonatal meningitis, pneumonia, gastroenteritis, and urinary tract infections (UTIs).
drugs effective against S. pyogenes.
Penicillin is usually effective Erythromycin or cephalosporin is used to treat penicillin-sensitive patients. S. pyogenes is also susceptible to the topical antimicrobial bacitracin
drugs that work against group B Streptococcus
Penicillin or ampicillin
treatment for Streptococcus pneumoniae
Penicillin, cephalosporin, macrolide, fluoroquinolone
Pertussis toxins
Pertussis toxin a portion of which interferes with the ciliated epithelial cell's metabolism, resulting in increased mucus production.Adenylate cyclase toxin which triggers increased mucus production and inhibits leukocyte movement, endocytosis, and killing. Dermonecrotic toxin which causes localized constriction and hemorrhage of blood vessels, resulting in cell death and tissue destruction. Tracheal cytotoxin which at low concentrations inhibits the movement of cilia on ciliated respiratory cells, and at high concentrations causes the expulsion of the cells from the lining of the trachea.
Group A Streptococcal Diseases
Pharyngitis
diseases caused by Streptococcus pneumoniae
Pneumococcal pneumonia community-acquired pneumonia (CAP) sinusitis otitis media bacteremia endocarditis pneumococcal meningitis
Pneumococcal meningitis
Pneumococci can spread to the meninges via bacteremia, during sinusitis or otitis media, or following head or neck surgery or trauma that opens a passage between the pharynx and the subarachnoid space of the meninges.
Streptococcus pneumoniae Virulence factors
Polysaccharide capsule, phosphorylcholine, protein adhesin, pneumolysin
Which diseases associated with Streptococcus pyogenes result from an adaptive immune response to bacterial antigens?
Press enter after select an option to check the answer Rheumatic fever and glomerulonephritis
What is the most significant risk factor associated with pseudomembranous colitis
Prolonged use of broad-spectrum antimicrobial drugs
Noncoliform Opportunistic Enterobacteriaceae
Proteus, Morganella, Providencia, and Edwardsiella. cannot ferment lactose
Gammaproteobacteria pseudomonads
Pseudomonads are Gram-negative, aerobic bacilli in the class Gammaproteobacteria. Pseudomonas, Moraxella Acinetobacter Francisella Legionella Coxiella.
Your patient is developing a blue-green infection in one of his wounds caused by a severe burn. Which organism would likely be responsible for this infection?
Pseudomonas
A cystic fibrosis patient develops a severe respiratory infection that resists treatment with standard antibiotics. A specimen from the lungs is greenish in color and contains aerobic motile Gram-negative bacilli. The patient is probably infected with
Pseudomonas aeruginosa.
Paracoccidioidomycosis
Pulmonary disease found from southern Mexico to South America caused by infection with Paracoccidioides brasiliensis
histoplasmosis
Pulmonary, cutaneous, ocular, or systemic disease found in the Ohio River valley and caused by infection with Histoplasma capsulatum
Pseudomonas infections in burn wounds
Pyocyanin pigment produces a blue-green pus Produce a grape-like, fruity odor
After Gram staining, Pneumococci are identified by the
Quellung reaction, in which anticapsular antibodies cause the capsule that the organism produces to swell.
deoxyribonucleases
Reduce the firmness of pus Facilitate the spread of Streptococcus
3 rickettsias that cause forms of typhus
Rickettsia prowazekii R. typhi Orientia tsutsugamushi.
Which bacterium causes Rocky Mountain spotted fever?
Rickettsia rickettsia
bacteremia
S. aureus is a common cause the presence of bacteria in the blood. After staphylococci enter the blood from a site of infection, they travel to other organs of the body, which may become infected. Furuncles, vaginal infections, infected surgical wounds, and contaminated medical devices such as intravascular catheters have all been implicated in cases of bacteremia.
endocarditis
S. aureus may attack the lining of the heart (including its valves) Typically, patients with endocarditis have nonspecific, flu like symptoms, but their condition quickly deteriorates as the amount of blood pumped from the heart drops precipitously.
sinusitis and otitis media
S. pneumoniae can also invade the sinuses and middle ear, where it causes sinusitis: inflammation of the nasal sinuses Otitis media: inflammation of the middle ear Pus production and inflammation in these cavities create pressure and pain.
Secondary syphilis
Second phase of the sexually-transmitted disease caused by Treponema pallidum characterized by sore throat, headache, mild fever, malaise, diseased lymph nodes, and a widespread rash
Lymphogranuloma venereum
Sexually transmitted disease caused by infection with Chlamydia trachomatis and leading in some cases to proctitis or, in women, pelvic inflammatory disease
impetigo
Small, flattened, red patches on the face and limbs, particularly of children whose immune systems are not fully developed, characterize S. aureus acting alone causes about 80% of impetigo cases; about 20% of cases also involve streptococci.
The genus _________ may include pathogenic species that are responsible for causing diseases such as botulism, gas gangrene, and tetanus.
Staphylococcus aureus
Two species are commonly associated with staphylococcal diseases in humans
Staphylococcus aureus is the more virulent, producing a variety of disease conditions and symptoms depending on the site of infection. Staphylococcus epidermidis as its name suggests, is a part of the normal microbiota of human skin, but it is an opportunistic pathogen in immunocompromised patients or when introduced into the body via intravenous catheters or on prosthetic devices, such as artificial heart valves. Both species also grow in the upper respiratory, gastrointestinal, and urogenital tracts of humans Both bacteria are transmitted through direct contact between individuals as well as via fomites such as contaminated clothing, bedsheets, and medical instruments;
Methicillin-resistant Staphylococcus aureus (MRSA)
Staphylococcus aureus (MRSA) has emerged as a major problem, initially in health care settings, where it's known as healthcare-associated MRSA, MRSA is also resistant to many other common antimicrobial drugs, including penicillin, macrolides, aminoglycosides, and cephalosporin; vancomycin has been used to treat MRSA infections
systemic diseases
Staphylococcus aureus and, to a lesser extent, S. epidermidis cause a wide variety of potentially fatal systemic infections when they are introduced into deeper tissues of the body, including the blood, heart, lungs, and bones.
cutaneous disease
Staphylococcus aureus causes localized pyogenic lesions. Various skin conditions Scalded skin syndrome, impetigo, folliculitis
How are infections that are caused by Staphylococcus aureus distinguished from other staphylococcal infections?
Staphylococcus aureus is coagulase positive.
pneumonia
Staphylococcus in the blood can invade the lungs, causing inflammation of the lungs in which the alveoli (air sacs) and bronchioles (smallest airways) become filled with fluid.
Osteomyelitis
Staphylococcus invades a bone, either through a traumatic wound or via the blood during bacteremia, causes inflammation of the bone marrow and the surrounding bone.
gram positive pathogens
Staphylococcus, Streptococcus, Bacillus, and Clostridium
vancomycin has been used to treat MRSA infections
Staphylokinase
Bacteremia and endocarditis
Streptococcus pneumoniae can enter the blood either through lacerations (as might result from vigorous tooth brushing, chewing hard foods, or dental procedures) or as a result of tissue damage in the lungs during pneumonia.
The bacterium Streptococcus mutans has a major role in the development of dental plaque and caries.
TRUE
Aspergillosis
Term for several localized and invasive diseases caused by infection with Aspergillus species
Streptococcus pneumoniae
The bacterium is a Gram-positive coccus round, mucoid, unpigmented, and dimpled in the middle a normal member of the pharyngeal microbiota that can colonize the lungs, sinuses, and middle ear. surrounded by a polysaccharide capsule, which protects them from digestion after endocytosis.
Why can cutaneous anthrax be lethal in as much as 20% of cases if left untreated?
The bacterium secretes toxin into the blood.
Pneumococcal pneumonia
The disease results when pneumococci are inhaled from the pharynx into lungs damaged either by a previous viral disease, such as influenza or measles, or by other conditions, such as alcoholism, congestive heart failure, or diabetes mellitus.
Lipid A
The lipid component of lipopolysaccharide, which is released from dead Gram-negative bacterial cells and can trigger shock and other symptoms in human hosts. Lipid A triggers fever, vasodilation, inflammation, shock, and disseminated intravascular coagulation (DIC)
What is the difference between a mechanical and a biological vector of a disease?
The microbe that causes the disease must complete part of its life cycle in a biological vector.
Coliforms
The most common of the opportunistic coliform pathogens are bacteria in the genera Escherichia, Klebsiella, Serratia, Enterobacter, Hafnia, and Citrobacter. which rapidly ferment lactose, are part of the normal microbiota and may be opportunistic pathogens.
Which of the following statements about Escherichia coli are incorrect?
The organism is non-motile and forms capsules.
Which sign is characteristic of diphtheria?
The presence of a pseudomembrane in the back of the throat
A lab report on a respiratory patient's sample contains the notation MDR-TB. What does this mean
The two standard drugs for TB, isoniazid and rifampin, are not effective.
Why can't scrub typhus be transmitted directly from one person to another by an arthropod vector?
The vector only takes one blood meal in its life.
How is impetigo distinguished from staphylococcal scalded skin syndrome?
The vesicles of impetigo are filled with pus, while those of staphylococcal scalded skin syndrome are filled with clear fluid.
Enterotoxins
These five proteins (designated A through E) stimulate the intestinal muscle contractions, nausea, and intense vomiting associated with staphylococcal food poisoning. Enterotoxins are heat stable, remaining active at 100°C for up to 30 minutes.
Based on genetic analysis, Mycoplasma spp. are classified as Gram-positive bacteria. Why were they classified as Gram-negative bacteria in the past?
They appear pink when a Gram stain is performed.
How do the structural characteristics of pathogenic Neisseria species contribute to their ability to cause disease
They facilitate attachment to human cells.
How do the structural characteristics of pathogenic Neisseria species contribute to their ability to cause disease?
They facilitate attachment to human cells.
Members of the Enterobactericeae produce siderophores. What function do siderophores perform?
They facilitate bacterial replication by obtaining iron from host cells.
Secretory IgA protease
This S. pneumoniae virulence factor destroys IgA antibodies bound to epithelial cells, which would normally prevent it from reaching the lower airways:
phosphorylcholine
This chemical secreted by S. pneumoniae encourages the immune system to engulf it, but as it is immune to digestion it can use the leukocyte to spread:
Toxic shock syndrome (TSS) toxin
This protein causes toxic shock syndrome When strains of Staphylococcus that produce TSS toxin grow in a wound or in an abraded vagina, the toxin can be absorbed into the blood and cause toxic shock syndrome, non-streptococcal (TSS), characterized by fever, vomiting, red rash, extremely low blood pressure, and loss of sheets of skin
How is Neisseria meningitidis transmitted?
Through respiratory droplets
Which toxin of Bordetella pertussis inhibits cells that line the trachea?
Tracheal cytotoxin
Bartonella quintana
Trench fever, spread by lice
Treponema pallidum can be transmitted
Treponema pallidum can be transmitted Group of answer choices
consumption
Tuberculosis; refers to wasting away of a body affected with TB at several sites
VRSA
Vancomycin-resistant Staphylococcus aureus
alpha-hemolytic streptococci
Viridans group many of them produce a green pigment when grown on blood media. Abiotrophia S. mitis S. mutans S. sanguis Members of the group are alpha-hemolytic and susceptible to penicillin. normally inhabit the mouth, pharynx, GI tract, genital tract, and urinary tract of humans. hey are one cause of dental caries
Which streptococcus usually causes dental caries?
Viridans streptococcus
What characteristic do all coliform bacteria share?
What characteristic do all coliform bacteria share?
Erysipelas
When a streptococcal infection also involves surrounding superficial lymphatic tissue and triggers pain and inflammation
What is the characteristic lesion of Yersinia pestis
a bubo
Tetanospasmin (tetanus toxin)
a potent neurotoxin released by C. tetani cells when they die. blocks the inhibitory neurotransmitter. With inhibition blocked, excitatory activity is unregulated, and muscles are signaled to contract simultaneously The result is that muscles on both sides of joints contract and do not relax. Opposing contractions can be so severe that they break bones.
tetanus
a sustained muscular contraction resulting from a rapid series of nerve impulses
Buboes
a swollen, inflamed lymph node in the armpit or groin.
Resistance of Pseudomonas to a wide range of antibacterial agents is partly due to its
ability to metabolize many drugs.
Disseminated Intravascular Coagulation (DIC)
abnormal activation of the proteins involved in blood coagulation, causing small blood clots to form in vessels and cutting off the supply of oxygen to distal tissues
disseminated intravascular coagulation (DIC)
abnormal activation of the proteins involved in blood coagulation, causing small blood clots to form in vessels and cutting off the supply of oxygen to distal tissues
empyema
accumulation of pus in the pleural cavity In 10% of patients with staphylococcal pneumonia, infection spreads to the space between a lung and the chest wall where pus builds up
microbiome
all of the microorganisms that live in a particular environment, such as a human body
Clostridium botulinum
an anaerobic, endospore-forming, Gram-positive bacillus that is common in soil and water worldwide. Its endospores survive improper canning of food, germinating to produce vegetative cells that grow and release into the jar or can a powerful neurotoxin that causes botulism
Bacteroides
anaerobes that live as part of the normal microbiota of the intestinal tract and the upper respiratory tract. Being Gram-negative, they have an outer wall membrane containing lipopolysaccharide.
pyoderma
any acute, inflammatory, pus-forming bacterial skin infection such as impetigo
chlamydias
are cellular and possess DNA, RNA, and functional 70S ribosomes. Each chlamydial cell is surrounded by two membranes, similar to a typical Gram-negative bacterium but without peptidoglycan between the membranes—chlamydias lack cell walls.
Streptococcus equisimilis and S. anginosus
are the only other pathogenic beta-hemolytic streptococci. S. equisimilis causes pharyngitis (and occasionally glomerulonephritis), but, unlike group A streptococci, these cases of pharyngitis never lead to rheumatic fever. S. anginosus causes pharyngitis. Penicillin is effective against both species.
The cells of S. aureus
are uniformly coated with a protein, called protein A, that interferes with antibody immune responses by binding to the stems of class G antibodies (IgG). The outer surfaces contain bound coagulase, an enzyme that converts the soluble blood protein fibrinogen into long, insoluble fibrin molecules, slime layer catalase Hyaluronidase staphylokinase lipase b lactamase
Mycoplasma pneumoniae causes respiratory disease by
attaching to and ultimately killing the ciliated epithelial cells of the trachea.
Serratia
bacteria associated with Red pigmentation can grow on catheters, in saline solutions, and on other hospital supplies and that it is a potentially life-threatening opportunistic pathogen in the urinary and respiratory tracts of immunocompromised patients frequently resistant to antimicrobial drugs.
furuncle
boil, is a large, painful, raised nodular extension of folliculitis into surrounding tissue. When several furuncles coalesce, they form a carbuncle which extends deeper into the tissues, triggering the fever and chills that are characteristic of innate immunity.
Hyaluronidase
breaks down hyaluronic acid, which is a major component of the matrix between cells. Hyaluronidase, found in 90% of S. aureus strains, enables the bacteria to spread between cells throughout the body.
Brucella melitensis
brucellosis though they can cause sterility or abortion. Historically named Brucella melitensis infects goats and sheep; Humans become infected either by consuming unpasteurized contaminated dairy products or through contact with animal blood, urine, or placentas in workplaces such as slaughterhouses, veterinary clinics, and feedlots. The bacterium enters the body through breaks in mucous membranes of the digestive and respiratory tracts.
E. coli in the blood
can colonize the lining of the heart, triggering inflammation and the destruction of heart valves (endocarditis).
K antigens
capsular antigens
Bartonella henselae
cat scratch disease when the bacterium is introduced into humans through cat scratches and bites. Fleas may also transmit the bacterium from cats to people.
The presence of ________ can be used to distinguish Staphylococcus from other Gram-positive cocci.
catalase enzyme
Bordetella pertussis
causes disease by interfering with the action of ciliated epithelial cells of the trachea. Various adhesins and toxins mediate the disease. The bacterium attaches to certain lipids in the cytoplasmic membranes of tracheal cells via two adhesins: filamentous hemagglutinin and pertussis toxin
Rickettsia typhi
causes murine typhus the major reservoir for the bacterium is rodents.
necrotizing fasciitis
characterized by redness, intense pain, and swelling at the site of infection. Initially, the pain does not seem proportionate to the appearance of the infected area. As the bacterium digests muscle fascia-the connective tissue surrounding muscles-and fat tissue, the overlying skin becomes distended and discolored. Patients develop fever, nausea, and malaise, and they may become mentally confused as their blood pressure drops severely.
Trachoma
chronic, contagious form of conjunctivitis that typically leads to blindness
To culture members of the Enterobacteriaceae from clinical specimens
clinicians use selective and differential media such as eosin methylene blue (EMB) agar and MacConkey agar.
Type III secretion system
common in pathogenic bacteria; secreted protein translocated directly into host
Enterobacteriaceae and Pasteurellaceae
contain most of the Gram-negative pathogens of humans.
Providencia
contains a plasmid that codes for urease and thus may trigger the formation of kidney stones.
Lipases
digest lipids, allowing staphylococci to grow on the surface of the skin and in cutaneous oil glands. All staphylococci produce lipases
Corynebacterium
diphtheria bacteria divide via a type of binary fission called snapping division`
gonococci
diplococci that invades the reproductive organs causing gonorrhea, a sexually transmitted disease
Lipid A triggers fever, vasodilation, inflammation, shock, and
disseminated intravascular coagulation (DIC
Which of the following is the correct sequence for stages of Ehrlichia development in infected host cells?
elementary body, initial body, morula
Which systemic disease caused by Staphylococcus aureus involves the buildup of pus between the lungs and the chest wall?
empyema
Bacillus Gram-positive bacilli (rod-shaped cells)
endospore-forming and non-endospore-forming
Chlamydia trachomatis
enters a human body through abrasions and lacerations and infects a limited array of cells those that have receptors for elementary bodies, including cells of the conjunctiva and cells lining the mucous membranes of the trachea, bronchi, urethra, uterus, uterine (Fallopian) tubes, anus, and rectum. Reinfection in the same site by the same or a similar strain triggers a vigorous hypersensitive immune response that can result in blindness, sterility, or sexual dysfunction.
Streptokinase(Streptase)
enzyme that breaks down blood clots
C5a peptidase
enzyme that breaks down complement enzyme
Rickettsia prowazekii
epidemic typhus, which is also called louse-borne typhus because it is vectored by the human body louse, Pediculis humanus it has humans as its primary host, and the bacterium fills a host cell until the host cell breaks open, releasing the rickettsias. treated with doxycycline or chloramphenicol
GROUP A STREPTOCOCCUS secretes three distinct pyrogenic toxins that stimulate macrophages and helper T lymphocytes to release cytokines that in turn stimulate fever, a widespread rash, and shock.
erythrogenic toxins The genes for these toxins are carried on temperate bacteriophages, so only lysogenized bacteria—bacteria in which a virus has become part of the bacterial chromosome—secrete the toxins.
Clostridium botulinum releases an exotoxin (neurotoxin) that, when ingested, may cause
flaccid paralysis
peritrichous flagella
flagella that cover the surface of a cell
three manifestations of botulism
foodborne botulism pediatric wound botulism
Neisseria gonorrhoeae
gonorrhea
Neisseria
gonorrhea gram negative cocci nonmotile and typically arranged as diplococci aerobic bacteria oxidase positive
What is the best way to prevent healthcare-associated infections (HAIs) by members of the Enterobacteriaceae?
good hand washing hygiene
Acinetobacter
gram negative bacilli
Moraxella
gram negative cocci
Propionibacterium acnes
grows in the oil glands of the skin Excessive production of oil—called sebum—is triggered by the hormones of adolescence, particularly testosterone in males. The excess oil stimulates the growth and reproduction of the bacterium, which secretes chemicals that attract leukocytes. The leukocytes phagocytize the bacteria and release chemicals that stimulate local inflammation. . The leukocytes phagocytize the bacteria and release chemicals that stimulate local inflammation.
Gram-positive bacteria
have a thick layer of peptidoglycan anchored to the cytoplasmic membrane by lipoteichoic acid Gram-positive bacteria stain purple when Gram stained and generally fall within the phylum Firmicutes.
Gram-negative bacteria
have a thin layer of peptidoglycan in a periplasmic space between their cytoplasmic membrane and an outer membrane
Actinomycosis
hen it enters breaks in the mucous membranes resulting from trauma, surgery, or infection by other pathogens. Actinomycosis is characterized by the formation of multiple abscesses connected by channels in the skin or mucous membranes
Mycobacterium
high G + C, aerobic, Gram-positive bacillus (rod). Virulent strains produce cord factor, a cell wall component that produces strands of daughter cells that remain attached to one another in parallel alignments. Cord factor also inhibits migration of neutrophils and is toxic to mammalian cells. non-endospore-forming pathogen have cell walls containing an abundance of waxlike lipids, called mycolic acids Grow slowly Are protected from lysis Are capable of intracellular growth. Are protected from desiccation. They can remain viable in dried aerosol droplets for eight months. Are resistant to Gram staining, detergents, and many common antimicrobial drugs.
rapid strep test
identifies the presence of group A streptococcal antigens.
ELISA
identify group B streptococcal infections by means
Quellung reaction
in which anticapsular antibodies cause the capsule to swell. Antibodies against particular strains trigger Quellung reactions only against those strains.
community associated MRSA
increasing in day care centers, high school locker rooms, and prisons, where it's called community-associated MRSA
Tuberculosis (TB) (consumption)
infectious disease caused by Mycobacterium tuberculosis; lungs usually are involved, but any organ in the body may be affected can live and multiply within macrophages, where many antimicrobial drugs have little effect. The currently recommended treatment is a combination of four antimicrobials: isoniazid (INH), rifampin ethambutol or streptomycin and pyrazinamide for eight weeks, followed by isoniazid and rifampin for an additional eighteen weeks.
rheumatic fever
inflammation leads to damage of heart valves and muscle. Rheumatic fever is most common in five- to fifteen-year-old children.
glomerulonephritis
inflammation of the glomeruli and nephrons—which obstructs blood flow through the kidneys and leads to hypertension (high blood pressure) and low urine output.
pharyngitis
inflammation of the pharynx
How is pneumonic plague transmitted
inhalation of respiratory aerosols from a person infected with Yersinia pestis
Bartonella bacilliformis
invades and weakens erythrocytes, causing bartonellosis an often fatal disease characterized by fever, severe anemia, headache, muscle and joint pain, and chronic skin infections. Very small bloodsucking sand flies of the genus Phlebotomus transmit the bacterium, so the disease is endemic only in Peru, Ecuador, and Colombia, where such flies live
Genus Streptococcus
is a diverse assemblage of Gram-positive cocci arranged in pairs or chains. are catalase negative synthesize peroxidase and thus are facultatively anaerobic.
Leukocidin
is a fifth cytolytic toxin that lyses leukocytes specifically, providing Staphylococcus with some protection against phagocytosis
Staphylococcal Scalded Skin Syndrome
is a reddening of the skin that typically begins near the mouth, spreads over the entire body, and is followed by large blisters that contain clear fluid lacking bacteria or white blood cells. the syndrome is caused by a toxin released by bacteria growing on the skin rather than in the body. Within two days, the affected outer layer of skin (epidermis) peels off in sheets, as if it had been dipped into boiling water
Inhalation anthrax
is also rare in humans, as it requires inhalation of airborne endospores. After endospores germinate in the lungs, they secrete toxins that are absorbed into the bloodstream, producing toxemia.
Folliculitis
is an infection of a hair follicle in which the base of the follicle becomes red, swollen, and pus filled. When this condition occurs at the base of an eyelid, it is called a sty
Prevotella
is involved with other Gram-negative bacteria in about half of all sinus and ear infections and in almost all periodontal infections. cause gynecological infections such as pelvic inflammatory disease, pelvic abscesses, and endometriosis; brain abscesses; and abdominal infections. Treatment of Prevotella infections involves surgical removal of infected tissue and the use of intravenous carbapenem.
Anthrax
is primarily a disease of herbivores; humans contract the disease from infected animals. Anthrax is not normally transmitted from human to human. It can invade via one of three routes: inhalation of endospores, inoculation of endospores into the body through a break in the skin, or ingestion of endospores.
Cutaneous anthrax
is the most common in humans. It begins when a painless, solid, raised nodule forms on the skin at the site of infection. Cells in the affected area die, and the nodule spreads to form a painless, swollen, black, crusty ulcer called an eschar
Corynebacterium diphtheriae
is transmitted from person to person via respiratory droplets or skin contact. inhibits synthesis of polypeptides in eukaryotes. the action of the toxin is enzymatic, a single molecule of toxin can completely block all polypeptide synthesis, resulting in cell death. one of the more potent toxins known. signs and symptoms of diphtheria :fever, pharyngitis, and the oozing of a fluid composed of intracellular fluid, blood-clotting factors, leukocytes, bacteria, and the remains of dead cells of the throat. The fluid thickens into a pseudomembrane that can adhere tightly to the underlying tissues, completely occluding the respiratory passages and resulting in death by suffocation.
gastrointestinal anthrax
is very rare in humans but is common in animals; it results in intestinal hemorrhaging and eventually death
. What part of the body is infected in patients with pyelonephritis
kidneys
Mycobacterium leprae
leprosy which is also called by the less dreaded name Hansen's disease tuberculoid leprosy. lepromatous leprosy Leprosy is transmitted via person-to-person contact. infection presumably occurs via inhalation of respiratory droplets. Diagnosis is confirmed by a positive skin test with leprosy antigen (similar to the tuberculin skin test) or through direct observation of acid-fast bacilli (AFBs) in tissue samples or nasal secretions (in the case of lepromatous leprosy). therapy consists of administering multiple drugs, such as clofazimine, rifampin, or dapsone, for 12 months, though treatment can be lifelong for some patients.
Which component of a Gram-negative cell wall can cause fever, vasodilation, inflammation, shock, and blood clotting?
lipid a
Which of the following structures is only found in Gram-negative organisms?
lipid a
mycoplasmas
low gram positive Lack cell walls Sterols in plasma membrane are pleomorphic the smallest free-living microbes—that is, those that can grow and reproduce independently of other cells contain both functional RNA and DNA, and they divide by binary fission—traits that viruses lack.
Burkholderia pseudomallei
melioidosis, which is an Asian and Australian tropical disease that is emerging as a threat in other locales
Noncoliform
members of the normal microbiota do not ferment lactose but can be opportunistic pathogens.
semisynthetic form of penicillin
methicillin, which is not inactivated by b-lactamase
What is the antimicrobial agent of choice for treating Bacteroides infections?
metronidazole
Entner-Doudoroff pathway
most notably in Gram-negative bacteria, certain Gram-positive bacteria and archaea. Glucose is the starting product in the ED pathway and through a series of enzyme assisted chemical reactions it is catabolized into pyruvate.
Enterobacter, Hafnia, and Citrobacter
motile coliforms that can be opportunistic pathogens ferment lactose and reside in the digestive tracts of animals and humans as well as in soil, water, decaying vegetation, and sewage. All three genera are involved in healthcare-associated infections of the blood, wounds, surgical incisions, and urinary tracts of immunocompromised patients.
Clostridium difficile
motile, anaerobic intestinal bacterium produces two toxins (called toxins A and B) and the enzyme hyaluronidase. form oval, subterminal endospores. a common member of the intestinal microbiota, it can be an opportunistic pathogen in patients treated with broad-spectrum antimicrobial drugs, such as penicillin and cephalosporin. produces life-threatening pseudomembranous colitis Clostridium difficile can spread from asymptomatic carriers via airborne endospores that can survive five months or longer
Salmonella and Shigella, both causes of diarrhea, can be distinguished by which of the following tests?
motility
The cell wall found in the genus Mycobacterium contains
mycolic acids which makes them resistant to Gram staining.
Which of the following genera cannot be stained with the Gram stain?
nocardia
Staphylococcal syndromes and diseases can be categorized as
noninvasive, cutaneous, and systemic diseases.
Rickettsia
nonmotile, aerobic, intracellular parasites that live in the cytosol of their host cells. They possess an outer membrane of lipopolysaccharide with endotoxin activity. A loosely organized slime layer surrounds each cell. lives in ticks, fleas, and mice
Streptococcus pyogenes causes disease only when
normal competing microbiota are depleted when a large inoculum enables the streptococci to gain a rapid foothold before antibodies are formed against them when adaptive immunity is impaired
Foodborne botulism
not an infection but instead an intoxication (poisoning) caused by botulism toxin. following the consumption of toxin in home-canned foods or preserved fish. Antimicrobial drugs are not effective in treating foodborne botulism
B-lactamase (penicillinase)
now present in over 90% of S. aureus strains, breaks down penicillin. it does allow the bacteria to survive treatment with beta-lactam antimicrobial drugs, such as penicillin and cephalosporin.
Francisella tularensis
one of the more infectious of all bacteria: Infection requires as few as 10 organisms when transmitted by a biting arthropod or through unbroken skin or mucous membranes. intramuscular gentamicin is recommended for use against Francisella.
Enterobacteriaceae
oxidase negative members of the intestinal microbiota of most animals and humans. Those members that are motile have peritrichous flagella. All members of the family reduce nitrate to nitrite and ferment glucose anaerobically, though most of them grow better in aerobic environments.
scientists distinguish between members of the Enterobacteriaceae and Pasteurellaceae by performing an
oxidase test
Bacillary peliosis hepatis
patients develop blood-filled cavities in their livers.
Which of the following antimicrobials would not be a good treatment choice to treat a patient diagnosed with walking pneumonia?
penicillin
B. fragilis
pleomorphic bacillus that produces a number of virulence factors. It attaches to host cells via fimbriae and a polysaccharide capsule, the latter of which also inhibits phagocytosis. Should the bacteria become phagocytized, short-chain fatty acids produced during anaerobic metabolism inhibit the activity of lysosomes, enabling the bacteria to survive within phagocytes.
Pneumococcal Diseases
pneumococcal pneumonia sinusitis and otitis media bacteremia and endocarditis pneumococcal meningitis
M. pneumoniae
primary atypical pneumonia, or walking pneumonia. pleomorphic bacterium interrupts the normal removal of mucus from the respiratory tract, allowing colonization by other bacteria and causing a buildup of mucus that irritates the upper respiratory tract.
Streptococcus mutans
produce acids that dissolve tooth enamel
Shiga-like toxin
produced by E.Coli are identical in structure to Shigella Toxin, work by inhibiting 60S subunit of ribosomal protein and thus preventing protein synthesis
Clostridium perfringens
produces 11 toxins that lyse erythrocytes and leukocytes, increase vascular permeability, reduce blood pressure, and kill muscle cells, resulting in irreversible damage. commonly grows in the digestive tracts of animals and humans traumatic events such as a surgical incision, a puncture, a gunshot wound, crushing trauma, or a compound fracture introduces endospores into the body, they can germinate in the anaerobic environment of deep tissues.
The genus is the most common pathogen to cause acne
propionibacterium
Group B streptococci produce enzymes
proteases (that catabolize protein) hemolysins (that lyse red blood cells) deoxyribonuclease hyaluronidase
You have isolated an unknown pathogen from a patient suffering from a UTI. The organism is Gram negative, urease positive, and positive for hydrogen sulfide production. Which genus are you likely working with?
proteus
Pseudomonas produces a blue-green pigment called
pyocyanin
listeria
rarely pathogenic in healthy adults; infection in pregnant women, fetuses, newborns, the elderly, and immunocompromised patients can result in meningitis.
People spread S. pyogenes among themselves via
respiratory droplets, especially under crowded conditions, such as those in classrooms and day care centers.
Wound botulism
results from growth of C. botulinum in wounds
pediatric (infant) botulism
results from the ingestion of endospores, which then germinate and colonize the infant's gastrointestinal (GI) tract. crying, constipation, and "failure to thrive. pediatric botulism is often associated with the consumption of honey, parents are advised not to feed honey to infants under age one their intestinal microbiota are not sufficiently developed to inhibit the germination of C. botulinum endospores
Bacillus anthracis
rod-shaped, facultatively anaerobic, endospore-forming bacterium that normally dwells in soil. The tough external coat and the internal chemicals of endospores make these structures resistant to harsh environmental conditions, enabling Bacillus to survive in the environment for centuries or perhaps even longer.
scarlet fever
scarlatina often accompanies streptococcal pharyngitis when the infection involves a lysogenized strain of S. pyogenes.
Researchers differentiate species of Streptococcus using several different, overlapping schemes,
serological classification based on the reactions of antibodies to specific bacterial antigens type of hemolysis (alpha, beta, or gamma cell arrangement physiological properties as revealed by biochemical tests, and genetic analysis.
Which of the coliform bacteria may produce a red pigment at room temperature
serratia
Rickettsias and Chlamydias
small Gram negative, obligately intracellular bacteria
Clostridium tetani
small, motile, obligate anaerobe that produces a terminal endospore, giving the cell a distinctive lollipop appearance its endospores survive for years. Its toxin causes the disease tetanus.
The genus Corynebacterium reproduces via a special form of binary fission called
snapping division
Enterococcal infections may be difficult to treat because
strains resistant to frequently used antimicrobials—lactams, aminoglycosides, and vancomycin—are relatively common.
__________ streptococci normally colonize the lower gastrointestinal, genital, and urinary tracts.
strep b
Mycoplasma pneumoniae
strictly aerobic
The pathogenicity of Staphylococcus results from at least three features
structures that enable it to evade phagocytosis the production of enzymes the production of toxins.
petechiae
subcutaneous hemorrhages
Lymphogranuloma venereum
swelling of the inguinal lymph nodes and scarring of genital tissues The second stage of the disease involves the development of buboes (swollen lymph nodes) associated with lymphatic vessels draining the site of infection
Group A Streptococcus
synonymously known as S. pyogenes is a coccus that forms white colonies 1-2 mm in diameter surrounded by a large zone of beta-hemolysis after 24 hours on blood agar plates Pathogenic strains of this species often form capsules. S. pyogenes decreases the movement of white blood cells into a site of infection.
Both S. aureus and S. epidermidis also evade the body's defenses by
synthesizing loosely organized polysaccharide slime layers (sometimes called capsules) that inhibit chemotaxis of and endocytosis by leukocytes, particularly neutrophils. The slime layer also facilitates attachment of Staphylococcus to artificial surfaces, such as catheters, shunts, artificial heart valves, and synthetic joints.
Group B diseases
the bacterium is most often associated with neonatal bacteremia meningitis pneumonia
Proteus mirabilis
the most common species of Proteus associated with disease in humans, particularly with UTIs in patients with long-term urinary catheters.
high G+C Gram-positive bacteria
the rod-shaped genera Corynebacterium, Mycobacterium, and Propionibacterium and the filamentous, fungus-like Nocardia and Actinomyces.
How does the toxin from Clostridium tetani produce its action
the smaller polypeptide of its toxin can block the release of inhibitory neurotransmitters by inhibitory neurons in the central nervous system.
Physicians categorize rickettsial human infections into two main categories
the spotted fever group, which causes spotted fever rickettsioses, the typhus group, which causes different forms of typhus.
If staphylococci isolated from an infection are able to clot blood
then they are coagulase-positive S. aureus.
E. faecalis and E. faecium
they do have the ability to adhere to human epithelial cells, and they secrete bacteriocins, which are chemicals that inhibit the growth of other bacteria. cause serious disease if they are introduced into other parts of the body, such as the lungs, urinary tract, or bloodstream, via poor personal hygiene or intestinal laceration.
Low G+C Gram-positive bacteria
three genera of pathogenic spherical cells (cocci): Staphylococcus, Streptococcus, and Enterococcus; three genera of pathogenic rod-shaped cells (bacilli): Bacillus, Clostridium, and Listeria and the mycoplasmas, a group of bacteria that lack cell walls.
Cell-free coagulase
triggers blood clotting. Cell-free coagulase does not act on fibrin directly but instead combines with a blood protein before becoming enzymatic and converting fibrinogen to fibrin threads. Only S. aureus synthesizes coagulase; S. epidermidis and other species of Staphylococcus are coagulase negative.
A pregnant woman should avoid deli meats and unpasteurized cheeses due to possible contamination with Listeria monocytogenes.
true
Which of the following diseases can be prevented by vaccination?
typhoid fever
Pseudomonas aeruginosa
typically infects the lungs of cystic fibrosis patients, forming a biofilm that protects the bacteria from phagocytes.
Brucellosis in humans
undulant fever—and chills, sweating, headache, myalgia, and weight loss. Bang's disease Malta fever, rock fever of Gibraltar fever of Crete
Which of the following antimicrobial agents has become the drug of choice for treating MRSA infections?
vancomycin
Bacillary angiomatosis
vascular infection in AIDS
Which of the following streptococci is associated with dental caries?
viridans streptococci
filamentous hemagglutinin
virulence factor on surface of B. pertussis, an adhesin; promotes binding to ciliated cells which is important for colonization in an airway
S. pyogenes also produces two different, membrane-bound proteins, called streptolysins
which lyse red blood cells, white blood cells, and platelets; thus, these proteins interfere with the oxygen-carrying capacity of the blood, immunity, and blood clotting.
The "p" in the vaccine known as DTap will protect against which of the following diseases?
whooping cough
The disease pertussis is also commonly known as
whooping cough
