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= A Few Bacteria to Know =

When identifying a bacterium, the first step is Gram stain, which can tell us whether it has a Gram-positive or Gram-negative cell wall, and can give us information about the size and shape (bacilli or cocci, usually). Everyone needs to know how to interpret a Gram-stain report, since it is still one of the first pieces of information we get about a bacterial infection.
When identifying a bacterium, the first step is Gram stain, which can tell us whether it has a Gram-positive or Gram-negative cell wall, and can give us information about the size and shape (bacilli or cocci, usually). Everyone needs to know how to interpret a Gram-stain report, since it is still one of the first pieces of information we get about a bacterial infection.


== Gram-positive Bacteria ==
= Gram-positive Bacteria =


=== Cocci ===
== Cocci ==


==== Clusters or Groups ====
== Clusters or Groups ==


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==== Pairs or Chains ====
== Pairs or Chains ==


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=== Bacilli ===
== Bacilli ==


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== Gram-negative Bacteria ==
= Gram-negative Bacteria =


=== Bacilli ===
== Bacilli ==


==== Enterobacteraceae (Poop!) ====
== Enterobacteraceae (Poop!) ==


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==== Others ====
== Others ==


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=== Cocci ===
== Cocci ==


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== Miscellaneous Bacteria ==
= Miscellaneous Bacteria =


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| Atypical pneumonia
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[[Category:Handouts]]

Revision as of 20:15, 13 August 2019

When identifying a bacterium, the first step is Gram stain, which can tell us whether it has a Gram-positive or Gram-negative cell wall, and can give us information about the size and shape (bacilli or cocci, usually). Everyone needs to know how to interpret a Gram-stain report, since it is still one of the first pieces of information we get about a bacterial infection.

Gram-positive Bacteria

Cocci

Clusters or Groups

Species Clinical Syndromes
Staphylococcus aureus Purulent skin and soft tissue infections, abscesses, endocarditis, HAP/VAP, food poisoning
Coagulase-negative Staphylococci Line infections, UTIs (S. saprophyticus)

Pairs or Chains

Species Clinical Syndromes
Streptococcus pyogenes/GAS Cellulitis
Other Lancefield-group Streptococci Cellulitis, UTIs, endocarditis
Streptococcus pneumoniae Pneumonia, meningitis
Enterococcus spp. UTIs, line infections, endocarditis

Bacilli

Species Clinical Syndromes
Clostridium difficile/tetani/botulinum/perfringens Diarrhea/tetanus/botulism/nec. fasc.
Bacillus cereus Food poisoning
Other Bacillus species Contaminant
Listeria monocytogenes Meningitis

Gram-negative Bacteria

Bacilli

Enterobacteraceae (Poop!)

Species Clinical Syndromes
Yersinia/Shigella/Salmonella/E.coli O157:H7/Campylobacter Infectious diarrhea/dysentery
Escherichia coli Intraabdominal infections, UTIs, HAP/VAP
Klebsiella spp. Intraabdominal infections, UTIs, HAP/VAP
Proteus spp. Intraabdominal infections, UTIs, HAP/VAP
SPICE bugs Very resistant, generally use carbapenems empirically

Others

Species Clinical Syndromes
Pseudomonas aeruginosa Otitis externa, hot-tub folliculitis, UTIs, pneumonias... very resistant to antibiotics

Cocci

Species Clinical Syndromes
Neisseria meningitidis Meningitis
Neisseria gonorrhoeae Urethritis, PID, disemminated gonococcal infection

Miscellaneous Bacteria

Feature Species Clinical Syndromes
Acid-fast bacilli Mycobacterium tuberculosis Pulmonary tuberculosis, extrapulmonary tuberculosis
Spirochete Treponema pallidum Syphilis (primary, secondary, tertiary)
Spirochete Borrelia burgdorferi Lyme disease
Intracellular Chlamydia trachomatis Urethritis, PID
Intracellular Chlamydia pneumophila Atypical pneumonia
No cell wall Mycoplasma pneumoniae Atypical pneumonia