gram-positive cocci:
PURPLE=POSITIVE COLOR on Gram-stain
arrangements of cocci:
Coccus/Cocci (Plural): Single cocci, which is spherical or round (occasionally ovoid or elongated)
Diplococci: Pairs of spherical cocci, which may or may not be elongated and may or may not contain a capsule ("Diplo" means 2)
Staphylococci: Clusters or clumps of spherical/round cocci that may be irregular, grape-like, or in packets of 4 or 8, which divide along double axes
Sarcinae: Staphylococci in the process of dividing, found in packets of 8
Tetrad: Staphylococci in the process of dividing, found in packets of 4 (3D)
Streptococci: Round/spherical cocci in chains, which divide along a single axis
Diplococci: Pairs of spherical cocci, which may or may not be elongated and may or may not contain a capsule ("Diplo" means 2)
Staphylococci: Clusters or clumps of spherical/round cocci that may be irregular, grape-like, or in packets of 4 or 8, which divide along double axes
Sarcinae: Staphylococci in the process of dividing, found in packets of 8
Tetrad: Staphylococci in the process of dividing, found in packets of 4 (3D)
Streptococci: Round/spherical cocci in chains, which divide along a single axis
staphylococcus: overall grape-like clusters, tetrads or sarcinae (packets of 8) of Gpcs, which may be in the process of dividing and consists of >40 species
*NOTE: there may be broken off short pairs and chains in the process of staphylococcal division but overall there will be more grape-like clusters seen; Sometimes, large singular cocci may be seen as well (Ex: Micrococcus)
Staphylococcus aureus group: Staphylococcus aureus, S. simiae, S. aureus anaerobius
Staphylococcus auricularis
Staphylococcus carnosis group: S. carnosis, S. carnosis utilis
Staphylococcus epidermidis group: S. epidermidis, S. capitis, S. capitis urealyticus, S. saccharolyticus, S. caprae
Staphylococcus haemolyticus group: S. haemolyticus, S. hominis, S. hominis novobiosepticus, S. hominis novobiosepticus, S. devriesei (S. hominis and subspp are novobiocin-resistant)
Staphylococcus hyicus-intermedius group: S. chromogenes, S. felis, S. delphini, S. hyicus, S. intermedius, S. lutrae, S. microti, S. muscae, S. pseudointermedius, S. rostri, S. schleiferi, S. schleiferi coagulans,
Staphylococcus lugdunensis group: S. lugdunensis
Staphylococcus saprophyticus group: S. saprophyticus, S. saprophyticus bovis, S. xylosis, S. succinus, S. nepalensis, S. leei, S. kloosii, S. gallinarum, S. equorum, S. cohnii, S. cohnii urealyticus, S. arlettae
Staphylococcus sciuri group: S. sciuri, S. sciuri rodentium, S. sciuri carnaticus, S. fleurettii, S. lentus, S. vitulinus, S.stepanovicii (*Most of this group are oxidase +, the only group of staphylococci to possess this gene and cytochrome c oxidase enzyme)
Staphylococcus simulans group: S. simulans
Staphylococcus warneri group: S. warneri, S. pasteuri
Staphylococcus caseolyticus
Staphylococcus auricularis
Staphylococcus carnosis group: S. carnosis, S. carnosis utilis
Staphylococcus epidermidis group: S. epidermidis, S. capitis, S. capitis urealyticus, S. saccharolyticus, S. caprae
Staphylococcus haemolyticus group: S. haemolyticus, S. hominis, S. hominis novobiosepticus, S. hominis novobiosepticus, S. devriesei (S. hominis and subspp are novobiocin-resistant)
Staphylococcus hyicus-intermedius group: S. chromogenes, S. felis, S. delphini, S. hyicus, S. intermedius, S. lutrae, S. microti, S. muscae, S. pseudointermedius, S. rostri, S. schleiferi, S. schleiferi coagulans,
Staphylococcus lugdunensis group: S. lugdunensis
Staphylococcus saprophyticus group: S. saprophyticus, S. saprophyticus bovis, S. xylosis, S. succinus, S. nepalensis, S. leei, S. kloosii, S. gallinarum, S. equorum, S. cohnii, S. cohnii urealyticus, S. arlettae
Staphylococcus sciuri group: S. sciuri, S. sciuri rodentium, S. sciuri carnaticus, S. fleurettii, S. lentus, S. vitulinus, S.stepanovicii (*Most of this group are oxidase +, the only group of staphylococci to possess this gene and cytochrome c oxidase enzyme)
Staphylococcus simulans group: S. simulans
Staphylococcus warneri group: S. warneri, S. pasteuri
Staphylococcus caseolyticus
OTHER FACTS ABOUT STAPHYLOCOCCI:
- Catalase +
- Some are Coagulase +
- Others are Coagulase -
- Facultative anaerobes
- Grow in the presence of bile salts
- Growth may occur in 3.5% NaCl
- Bacitracin-resistant
- Furazolidone-susceptible
- Forms clumps/clusters of bacteria, due to its division along 2 axes rather than 1
- Cause many types of infections (opportunistic) in every part of the body: enteritis (food-poisoning), catheter, wound, eye, ear, respiratory, urinary, CNS, soft-tissue, deep, arthritis, bloodstream, nosocomial, etc...)
- Colonizes the skin of humans and some spp colonize various animals or birds
- An individual may be colonized with MRSA, which may cause opportunistic infections due to trauma
micrococcus: clusters of gpcs, mostly in tetrads
|
TYPES OF COAGULASE NEGATIVE STAPHYLOCOCCI:
Part of the transient skin flora of mammals and avian spp, CNS has been linked to occasional wound/skin or soft-tissue infections, endocarditis, or peritonitis. It harbors the methicillin-resistnat gene mecA, like S. aureus. It produces many virulence factors, including the ability to form biofilms, clumping, exotoxins, DNAse, and proteolytic activities. |
Kocuria kristinae (formerly known as Micrococcus kristinae) is a type of Micrococcus (GPC) in clusters, aerobic, that normally colonizes the skin. It has been implicated in IV catheter infections, in the formation of gallstones (acute cholecystitis), and urinary tract infections. It often produces an orange or yellow pigment on blood agar. Microscopically, it is seen in clusters, tetrads, sarcinae (packet of 8), and is a strict aerobe.
leuconostoc
FACTS ABOUT LEUCONOSTOC:
- Leuconostocaceae
- Ovoid cocci
- Seen in clusters and/or chains
- Catalase-negative
- Resistant to Vancomycin
- Slime-forming
- Lactic-acid producer
- Fermenter of cabbage, making it sauerkraut
- Involved in fermentation of kefir
- Some spp capable of causing human infection
Streptococcus in chains of gpcs
MEDICALLY RELEVANT STREPTOCOCCI:
- S. pyogenes-Group A, pharyngitis, some skin infections, invasive (sepsis, bacteremia), necrotizing fasciitis (rare)
- S. agalactiae-Group B, neonatal meningitis, sepsis
- S. equi-endocarditis, bacteremia and sepsis, respiratory and pneumonia, meningitis
- S. bovis-UTI, biliary infection, endocarditis
- S. anginosus-respiratory, meningitis, abscess
- S. sanguinis-endocarditis, oral and dental cavities
- S. suis-meningitis
- S. mitis-endocarditis, catheter
- S. mutans-oral and dental, endocarditis
- S. pneumoniae-pneumonia (May chain or be in pairs that are "lancet-shaped")
Enterococcus: short chains and pairs
FACTS ABOUT ENTEROCOCCUS:
- Some strains are resistant to Vancomycin, Gentamicin,
- Group D streptococci
- Tend to be elongated, ovoid-shaped cocci in short chains, pairs
- Normal flora of the GI and biliary tract, vaginal and male urethras (E. faecalis and E. faecium)
- Large resistance patterns (penicillin, cephalosporins, aminoglycoside, vancomycin)
- 2nd most common cause of nosocomial urinary tract infections and wound infections
- 3rd most common cause of nosocomial bacteremia (opportunistic)
- May cause a superinfection
- Other infections caused by this organism: endocarditis, meningitis, diverticulitis
- 90% possess the Lancefield Group D lipotechonic antigen in their cell wall
- E. faecalis (some high-level Vancomycin-resistant strains), E. faecium (some high-level Vancomycin-resistant strains), E. casseliflavus (inherent, low-level resistance to Vancomycin), E. gallinarum (inherent, low-level resistance to Vancomycin), E. raffinosus
- Some produce a yellow pigment, but most are tan-to-buff in color and are gamma-hemolytic (no hemolysis)
- Motile
- Have been recovered from plants, soil, and even chicken feces
- Facultative anaerobe
- Vancomycin resistance is due to plasmids or transposons that carry and encode genes which lead to the resistance to Vancomycin (Van-A, Van-B, Van-C, Van-D, Van-E, Van-F)
- Colonization and risk for infection with VRE may occur in patients treated with the Cephalosporins, especially heavy doses or long-term doses
- Able to form biofilm
- Treatment for infections: Nitrofurantoin, linezolid, daptomycin, ampicillin
Enterococcus faecalis and Enterococcus faecium are associated with urinary tract infections, bacteremia, endocarditis, and wound infections. Root canal infections, endocarditis, meningitis, and diverticulitis are other infections that may be caused by this organism. It is nonmotile, catalase negative, a facultative anaerobe, ferments lactose, does not produce gas