Study Set Content:
An anaerobic, spore-forming, Grampositive bacillus; it can colonize the intestinal tract, where overgrowth (superinfection) commonly occurs after ingestion of oral antibiotics; this organism produces two toxins—an enterotoxin that causes antibiotic associated diarrhea (AAD) and a cytotoxin that causes pseudomembranous colitis (PMC); a common cause of healthcare-associated infections
Clostridium difficile
An anaerobic, spore-forming, Grampositive bacillus; common in feces and soil; the most common cause of gas gangrene (myonecrosis); produces an enterotoxin that produces a relatively mild type of food poisoning.
Clostridium perfringens
An anaerobic, spore-forming, Gram-positive bacillus; common in soil; produces a neurotoxin called tetanospasmin, which causes tetanus.
Clostridium tetani
A pleomorphic, Gram-positive bacillus; toxigenic (toxinproducing) strains cause diphtheria, whereas nontoxigenic strains do not.
Corynebacterium diphtheriae (
Grampositive cocci; common members of the indigenous microflora of the gastrointestinal tract; opportunistic pathogens; a fairly common cause of cystitis and healthcare-associated infections; some strains, called vancomycinresistant enterococci (VRE), are multidrug resistant.
Enterococcus
A member of the family Enterobacteriaceae; a Gram-negative bacillus; a facultative anaerobe; a very common member of the indigenous microflora of the colon; an opportunistic pathogen; the most common cause of septicemia and urinary tract and healthcareassociated infections; some serotypes (called the enterovirulent E. coli) are always pathogens
Escherichia col
. A Gram-negative bacillus; the causative agent of tularemia; may enter the body by inhalation, ingestion, tick bite, or penetration of broken or unbroken skin; tularemia frequently follows contact with infected animals (e.g., rabbits)
Francisella tularensis
Anaerobic, Gram-negative bacilli; common members of the indigenous microflora of the oral cavity, gastrointestinal tract, and vagina; opportunistic pathogens that cause various infections, including oral and respiratory infections.
Fusobacterium
A fastidious, Gram-negative bacillus; a facultative anaerobe; encapsulated; found in low numbers as indigenous microflora of the upper respiratory tract; an opportunistic pathogen; a cause of bacterial meningitis, ear infections, and respiratory infections, but is not the cause of influenza (which is caused by influenza viruses); some strains are ampicillin resistant.
Haemophilus influenzae
Acurved, Gram-negative bacillus; capable of colonizing the stomach; a common cause of stomach and duodenal ulcers.
Helicobacter pylor
A member of the family Enterobacteriaceae; a Gramnegative bacillus; a facultative anaerobe; a common member of the indigenous microflora of the colon; an opportunistic pathogen; a fairly common cause of pneumonia and cystitis.
Klebsiella pneumoniae
Grampositivebacilli; some species are found in foods (e.g., yogurt,cheese); other species are common members of the indigenous microflora of the vagina and gastrointestinal tract; rarely pathogenic
Lactobacillus
An aerobic, Gram-negative bacillus; common in soil and water; the causative agent of legionellosis (a type of pneumonia); can contaminate water tanks and pipes; has caused epidemics in hotels, hospitals, and cruise ships.
Legionella pneumophila
A Gram-positive bacillus; the causative agent of listeriosis; can cause meningitis, encephalitis, septicemia, endocarditis, abortion, and abscesses; enters the body via ingestion of contaminated foods (e.g., cheese).
Listeria monocytogenes
An aerobic, acid-fast, Gramvariable bacillus; referred to as the leprosy bacillus or Hansen’s bacillus; the causative agent of leprosy (Hansen’s disease); transmitted from person to person; has been found in wild armadillos, which are now used as laboratory animals to propagate this organism.
Mycobacterium leprae
An acid-fast, Gramvariable bacillus; causes tuberculosis; many strains are multidrug resistant
Mycobacterium tuberculosis
A small, pleomorphic, Gramnegative bacterium; lacks a cell wall; the causative agent of atypical pneumonia.
Mycoplasma pneumoniae
Also known as gonococcus or GC; a fastidious, Gramnegative diplococcus; microaerophilic and capnophilic; always a pathogen; causes gonorrhea; many strains are penicillin resistant
Neisseria gonorrhoeae
Also known as meningococcus; an aerobic, Gram-negative diplococcus; found as indigenous microflora of the upper respiratory tract of some people (referred to as carriers); a common cause of bacterial meningitis; also causes respiratory infections
Neisseria meningitidi
Aerobic, acid-fast, Gram-positive bacilli; the causative agents of nocardiosis (a respiratory disease) and mycetoma (a tumorlike disease, most often involving the feet).
Nocardia
