Microbiology Review Flashcards
6/13/19
Facultative anaerobe
Capable of making ATP by aerobic respiration if O2 is available, but also capable of making ATP via fermentation if O2 is not present
Most common type of staph infection
Skin
Often the cause of infection of prosthetic implants
S. epidermidis, can develop factors that facilitate attachment to plastic surfaces to act as virulence factors
Streptococci
-Gram positive cocci that are often facultative anaerobes
a hemolysis
Incomplete destruction of erythrocytes, resulting in green coloration
B hemolysis
Complete destruction of erythrocytes results in clear distinct zone around colonies
gamma hemlysis
no hemolysis on blood agar, no visible effect on agar
Impetigo
Contagious skin infection accompanied by pus, common in children
Pharyngitis
Strep throat, often caused by S pyogenes that produes streptokinase which breaks down fibrin clots and permits the organism to spread to other tissues, large lymph nodes with inflamed tissues and tonsils
Pharyngitis
Strep throat, often caused by S pyogenes that produes streptokinase which breaks down fibrin clots and permits the organism to spread to other tissues, large lymph nodes with inflamed tissues and tonsils
Examples of post infection diseases
-Acute glomerulonephritis (antibody to specific antigen buildup in kidney)
-Rheumatic fever (inflammation of heart tissues and around the joints producing rheumatoid arthritis)
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Examples of post infection diseases
- Acute glomerulonephritis (antibody to specific antigen buildup in kidney)
- Rheumatic fever (inflammation of heart tissues and around the joints producing rheumatoid arthritis)
Viridan’s streptococci causes….
…-dental caries, bacterial endocarditis
Enterococci
Formerly known as group D streptococci, are part of normal fecal flora, but can colonize oral mucosa membranes and skin, particularly in a hospital setting. Very resistant to environment, fairly common cause of nosocomial infections
VRE
Vancomycin resistant enterococci
N. gonorrhoeae
Does not produce a capsule, causees gonorrhea, transmitted by sexual contact, frequent cause of PID and sterility in females
N. Meningidis
um
Moraxella genus common infections
Respiratory system, middle ear, eye, CNS, and joints, most common to see in imunocompromised hosts
Genus acetinobacter
Liimited pathogenic potential because they cannot produce toxins, can infect virtually any site of the body, often resistant to many forms of antibiotics
Bacilli
Genus of large gram positive rods characterized by their ability to produce endospores that are resistant to heat and chemicals
Anthrax toxin effects
Septicemia, meningitis, death
5 types of C. perfringens
Types A, C, and D cause disease in humans, 80% of environmental isolates belong to this type
Gas gangrene
caused by exotoxin producing clostridium species mostly found in soil, also gut flora, and contaminated food
C. tetani
Etiologic agent of tetanus due to release of exotoxin
C. Botulinum
Etiologic agent of botulism due to release of neurotoxin, most often in contaminated food such as home canned, low acid vegetables (don’t eat the bulged can!)
C. difficile
Associated with broad spectrum antibiotic therapy resulting in C diff overgrowth and secretion of cytopathic exotoxins
Enterobacteriaceae members
- salmonella
- Klebsiella
- Proteus
- e. coli
Most common cause of UTI
E. coli in the bladder
Enterobacter species
Occur as indigenous intestinal flora, rarely cause of infection but frequently colonize hospitalized patients and can cause wound infection, respiratory tract infection, or UTI
Serratia species
Important cause of nosocomial UTI, can also infect the lower respiraotyr fact
Proteus species
Gram negative rods, extremely motile opportunistic pathogens, do not cause infection unless adhere to a place not normally found
Common cause of septicemia
S. choleraesius
S. enteridis
cause of gastroenteritis, particularly from undercooked chicken
Shigella species
Etiologic agents of bacillary dysentary, characterized by presence of inflammatory cells and occasionally blood in watery stools, non motile gram neg rods, humans are only reservoir of shigellae, acquiring by igesting contaminated food and water
Vibrio
Members are short, curved, gram negative rods, motile by means of polar flagella and closely rleated to enterobacteriaciae
Campylobacter and helicobacter
2 groups of gram neg organisms both curved and spiral shaped and are genetically related
Campylobacter
Curved, spiral, gram neg rods with single polar flagellum, may cause both intestinal and extraintestinal disease can cause acute enteritis following 1 to 7 days incubation, very preventable by fully cooking food
Helicobacter pylori
Gram negative microaerophilic bacterium found in stomach that produces urease, curved or spiral with rapid corscrew motility due to flagella, causes acute gastritis and duodenal and gastric ulcers, can colonize stomach
Bacteroides
Genus composed of obligate anaerobic gram neg rods that do not form spores, primarily inhabit the GI tract, may account for 99% of fecal flora, often seen in a mixed flora infection with other bacteria
Pseudomonads
Obligate aerobic gram negative rods, patients prone to infection are those receiving long term antibiotic therapy and UTI introduction from catheterization
Haemophilus species
Require components of blood for growth
H. ducreyi
Etiologic agent of conjunctivitis, forms chancre, sexually transmitted
Bordatella pertusis
Cause of whooping cough, 3 stage of disease, catarrhal stage, paroxymal stage, and convalescent stage
Zoonoses
Small gram negative rods that are etiologic agents of diseases in animals that can be transmitted to humans, include brucella species
Yersinia
Gram neg rod, cause of the plague (transmitted by rat flea), lymph node inflammation called bubonic plague, eventually becomes septicemic plague
Treponema species
Most important pathogen to humans is syphillis, transmitted during sexual contact (except in the case of congenital syphilis), if accelerated to tertiary phase can cause gumma formation which can cause CNS paralysis, aortic aneyrism
Borrelia burgdorferi
Lyme disease cause, causes bullseye rash on skin from tic bite
Mycobacteria
large lipids in their membrane make it hard to stain (acid fast), do not produce toxins but tissue damage due to local effects and host efforts, M. Tuberculosis is the key example, organisms inhaled as small droplet produced by individuals with active pulmonary infection, form tubercle (nodules on lung tissue) surrounded by macrophages and T lymphocytes
M. Leprae
Agent of leprosy/hansen’s disease, often seen in immigration to US, requires prolonged contact with individuals, cutaneous lepromas giving leonine appearance
Chlamydia
Obligate intracellular parasites (like viruses) have cell wall resembing gram neg bacteria, growth cycle takes place within host cells and differentiate into reticulate bodies
C. trachomatis
Cause of eye infecction worldwide distribution, most common form of neonatal conjuntivitis, rarely causes blindness, moreso seen in genital infections
C. psittaci
Psittacosis occurs naturally in a variety of wild and domestic birds, those who work around birds vulnurable
Rickettsia rickettsii
Causes rocky mountain spotted fever,
Mycoplasma pneumoniae
Causes micoplasma penumonia small bacteria that lack cell walls
Legionella pneumophila
Causes Legionnaire’s disease, exists where water collects and is airborne in wind gusts, erythromycin is used for therapy
Listeria monocytogenes
Small gram positive bacterium, can cause listeristic meningitis
