Staphylococcus and Related Organisms Ch 11, pg 539

1
Staphylococcus and Related Organisms Ch 11, pg
539

• Staphylococcus
• Micrococcus
• Rothia
• .

2
Preliminary Grouping of Gram Positive Cocci

• Gram Positive Coccus

Catalase
_

Streptococcus Group
Salt Tolerant
Yes
No
Rothia
Facultative
No
Yes
Staphylococcus
Micrococcus
3
General characteristics

• The Staphylococci belong to the family
  Micrococcocaceae (a.k.a. Staph group)
• Related bacteria encountered in human clinical
  specimens include Staphylococcus, Micrococcus,
  and Rothia mucilaginosus (formerly Stomatococcus
  mucilaginosus)
• At this time, there are 40 recognized species of
  the genus Staphylococcus
• There are only a few recognized species of
  Micrococcus and of Rothia

4
General characteristics

• The Staph group is comprised of Gram-positive
  cocci
• Based on planes of division they form various
  groupings which include clusters, tetrads, pairs,
  and even short chains
• When seen in pairs the longer axes are parallel
  rather than perpendicular (mutual)

5
General characteristics

• Species of the genus Staphylococcus divide in
  random planes and tend to form irregular clusters
  (Staphgrape-like clusters, coccusround)
• Micrococcus species first divide in parallel
  planes and them perpendicular to that resulting
  in predominance of tetrads
• Rothia species form short chains and small
  clusters. Here, the longer axes are
  perpendicular rather than rather than parallel.

6
Staph clusters
Micrococcus tetrads
Rothia
7
General characteristics

• Staphylococci have a thick multilayered
  peptidoglycan as the major component of their
  cell walls, the same as all Gram-positive
  bacteria
• Staphylococcus species contain teichoic
• acids in their cell walls
• Teichoic acids stabilize the cell wall, hold
  association with cell membrane, function in
  transport, etc.
• Cell walls of Micrococcus Rothia species do not
  contain teichoic acids

8
General characteristics

• Members of the staph group are mostly
  non-encapsulated and all clinically relevant ones
  are nonmotile
• All Staph group organisms that grow in air are
  catalase positive
• Rothia is catalase negative (or weakly positive).

9
General Clinical Significance

• Staphylococcus aureus is the most virulent
  pathogenic species in the group
• It is implicated in a variety of infections
  including skin, respiratory tract, post-op
  infections and other systemic infections such as
  TSS. S. aureus also causes food poisoning.
• All Staph group species, including S. aureus, can
  lead a commensal existence (as an opportunistic
  pathogen) in the skin and mucous membranes of
  humans and many other animals, including domestic
  pets and farm animals.

10
General Clinical Significance

• Staphylococcal infections are generally acute,
  often involve inflammation and suppuration (fluid
  product of inflammation)
• A small percentage of staphylococcal infections
  spread hematogenously to all regions of the body
  systemic bacteremia, and likely toxemia.

11
General Clinical Significancenot on test

• In addition to the coagulase positive S. aureus
  the most clinically significant species are
• S. epidermidis
• S. saprophyticus
• S. haemolyticus
• S. lugdunensis
• S. schleiferi
• S. intermedius
• S. hyicus

Coagulase negative
Coagulase positive
12
General Clinical Significance

• S. intermedius is most often an inhabitant of
  dogs and S. hyicus is an inhabitant of swine
• S. intermedius infections in humans are usually
  associated with dog bites (and are probably
  identified incorrectly as S. aureus since the
  human clinical laboratories rely primarily on the
  coagulase test)
• Micrococcus species and R. mucilaginous are
  rarely pathogenic but must be differentiated from
  phenotypically similar Staphylococcus species

13
General Growth Characteristics

• Staphylococcus species are generally
  nonfastidious
• They grow well on media without blood or other
  special supplements
• Micrococcus species and R. mucilaginosa are
  mildly fastidious and grow more slowly than
  Staphylococcus sp.

14
General Growth Characteristics

• Staphylococcus and Micrococcus tolerate a high
  salt concentrations they grow on media
  containing 5-7.5 NaCl (e.g. Mannitol Salt Agar)
• Staphylococcus species are facultatively
  anaerobic, as is Rothia. Micrococcus is an
  obligate aerobe.
• Staphylococcus species produce a variety of
  hemolysins and other toxins

15
General Cultural Characteristics

• Some Staphylococcus species, most notably S.
  aureus, produce a hemolysin that completely
  lyses red blood cells of humans and some other
  mammals (sheep blood). This is referred to as
  beta hemolysis.
• None are alpha hemolytic (removal of potassium
  from RBCs) as is Streptococcus pneumoniae
• Morphology (color, shape, surface, etc) of staph
  colonies may change with age

16
General Cultural Characteristics

• Staphylococcus colonies have a convex profile and
  color ranges from white (ex S. epidermidis, S.
  saprophyticus) to yellowish brown (S. aureus)
• Micrococcus colonies are usually not as shiny as
  Staphylococci and have a high convex profile
• The most commonly isolated Micrococcus species,
  M. luteus, is yellow

17
General Cultural Characteristics

• Colonies of R. mucilaginosus are distinctly
  convex and gray-white
• They usually are not as shiny as Staphylococcus
• Colonies of R. mucilaginosus are described as
  having a gumdrop consistency they tend to
  adhere to an agar surface
• R. mucilaginosus is very difficult to emulsify
  when preparing smears for staining

18
General Cultural Characteristics

• Many strains of S. aureus have a golden color
  (aureusgolden) on certain media after prolonged
  incubation
• This pigmentation is usually more pronounced when
  the culture is kept at room temperature for
  several days
• This golden color is not unique to Staphylococcus
  aureus
• Additionally, many S. aureus isolates are white
• Pigmentation, except for the most common species
  of Micrococcus ( M. luteus), is therefore not a
  reliable criterion for identifying the
  Staphylococci

19
Biochemical characteristic

• Production of catalase is a defining
  characteristic of the Staphylococcus and
  Micrococcus species
• The catalase reaction of Rothia is weak or
  delayed and many are frankly catalase negative

20
Biochemical characteristic

• Staphylococcus species can be differentiated from
  Micrococcus species based upon oxygen
  requirements Staph is facultative and
  Micrococcus species are obligate aerobes
• Rothia can be differentiated from Staphylococcus
  and Micrococcus by its lack of growth on a
  high-salt medium, its negative catalase reaction,
  and its tendency to adhere firmly to an agar
  surface

21
Presumptive Genus Identificationtable not on test
6.5 Furazoli- Modified 0.04 U
Salt done oxidase
Bacitracin Micrococcus R
S Staphylococcus S -
R R. mucilaginosa - NT NT
NT Not included oxygen requirements
22
Coagulase

• Coagulase (staphylocoagulase) is a fibrinogen
  activating enzyme produced by some staph species
  - it has thrombin-like activity. In situ,
  coagulase combines with coagulase reacting
  factor (CRF) to catalyze the formation of fibrin
  clots around cells as a barrier to host immune
  components it is a virulence factor.
• Clinically significant staphylococci are usually
  divided into two groups those that produce
  coagulase and those that do not
• Coagulase positive species include S. aureus, S.
  intermedius and S. hyicus
• S. intermedius and S. hyicus mostly inhabit
  animals and are only rarely found as a cause of
  human infections

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Coagulase
Normal coagulation of plasma
Thrombin Fibrinogen

Fibrin (soluble )
(insoluble)
Staphylococcus aureus coagulation of plasma
Free staphylocoagulase
Fibrinogen CRF
Fibrin
EDTA Rabbit plasma is preferred for the free
or tube coagulase test because it contains a
large amount of CRF
24
Coagulase testing

• Since staphylocoagulase is synthesized and
  secreted into the medium in which it is
  growing, it is known as free coagulase (i.e. it
  is not bound to the cell that secreted it)
• The free coagulase test is performed by mixing a
  Staphylococcus colony or growth from a broth
  with a small amount of plasma in a test tube
• It is therefore usually referred to as the tube
  coagulase test (a free coagulase test and a
  tube coagulase test is the same thing)

25
Coagulase testing

• Rabbit plasma is preferred for the free (tube)
  coagulase test because it has more CRF than
  plasma from other species of animals including
  human plasma
• Cells of the test organism is mixed with rabbit
  plasma in a test tube and incubated at 35oC for
  up to 4 hours

26
Coagulase testing

• The tube is observed hourly during the four hour
  incubation period
• The formation of a fibrin clot or gel indicates
  a positive test

27
Coagulase testing

• S. aureus is the only coagulase positive species
  found in human clinical specimens with any
  frequency (see previous discussion)
• In addition to staphylocoagulase some strains of
  S. aureus will produce staphylokinase
  (fibrinolysin)
• This enzyme will dissolve a fibrin clot (i.e.
  will have the opposite effect of coagulase)

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Coagulase testing

• This could be a cause of false negative
  coagulase tests if tubes are not examined
  regularly over the four hour period
• If the plasma gels before 4 hours the test is
  read as positive and discarded
• Only catalase positive Gram positive cocci should
  be tested for tube coagulase as some other
  organisms such as Enterobacter Klebsiella can
  give false positive results.

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Coagulase testing

• Using rabbit plasma containing EDTA as
  anticoagulant will avoid the false positive tube
  coagulase tests caused by citrate consuming
  bacteria
• This will not be a problem if only catalase
  positive Gram-positive cocci are tested for
  coagulase

30
Clumping Factor

• 95 of S.aureus isolates produce a separate
  enzyme that catalyzes the formation of fibrin
  from fibrinogen
• This enzyme is referred to as bound coagulase
  because it is an integral part of the cell wall
  of S. aureus
• Bound coagulase is not secreted into the
  surrounding medium
• Unlike free coagulase this enzyme does not
  require CRF in the plasma substrate

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Clumping Factor

• It is also called slide coagulase or the
  clumping factor test. A clumping factor
  test, a bound coagulase test, and a slide
  coagulase test are synonymous.
• This is because the test is performed on a slide
  and the end point is the clumping of a heavy
  water or saline suspension of bacteria taken from
  an agar culture
• A loopful of plasma is thoroughly mixed with the
  heavy bacterial suspension on a slide and
  observed for clumping

32
Clumping Factor

• Clumping of the suspension within 10 seconds
  indicates a positive test
• Human plasma is preferable to rabbit plasma for
  the slide coagulase test because it yields more
  consistent results.
• Note Your textbook indicates that rabbit plasma
  is used for both coagulase test this is contrary
  to the Staphylococcus chapter in the bible (The
  Manual of Clinical Microbiology published by The
  American Society for Microbiology)

33
Clumping Factor

• The heavy cell suspension is first made in water
  or saline
• If clumping occurs prior to the addition of
  plasma this invalidates the test (false
  positive). Such strains are termed
  autoagglutinable and must be tested by the tube
  method.
• Since 5 of S.aureus produce free coagulase but
  not bound coagulase, an organism giving a
  negative clumping factor test must still be
  tested by the tube test

34
Protein A

• Protein A is unique to, and is an integral part
  of the cell wall surface of S. aureus. Protein A
  has an anti-phagocytic property (a virulence
  factor).
• Protein A also has the unusual ability to bind
  specifically to Fc fragments of IgG (a sort of
  antigen-antibody reaction) from several species
  of animals, including Homo sapiens. This makes
  it well adapted for another test

35
Protein A clumping test

• A diagnostic tool utilizes IgG adsorbed to some
  visible inert particle (such as latex beads)
  forming the basis of another clumping test for
  identifying S. aureus called the protein A
  clumping test. If you remember from Micro, this
  is an example of what we called an
  agglutination-type test.
• IgG coated particles are mixed with cells taken
  from an agar culture. The complex forms within
  10 seconds in the presence of S. aureus appearing
  as large granular-firm (not stringy) clumps
• This test is claimed to be about 99 specific and
  sensitive for S. aureus

36
Protein A Latex Test
L
S
L

IgG
S
L
S
S
S
L
Fc
L
S
SS.aureus with Protein A LLatex particle
S
Protein A
S
37
Protein A/Clumping factor

• Some reports in the literature indicate that an
  occasional methicillin resistant S. aureus (MRSA)
  will give a negative protein A/clumping factor
  test
• Authors of these reports recommend that isolates
  that resemble colonies of S. aureus giving a
  negative protein A/clumping factor test and are
  also resistant to methicillin be tested by the
  tube coagulase method
• The Protein A test should only be used on
  isolates that presumptively ID (morphology,
  catalase, salt tollerance, mannitol fermentation,
  etc) as S. aureus since some organisms give a
  false positive reaction (Enterococcus,
  Micrococcus and rare strains of Staphylococcus
  saprophyticus). These false positive reactions
  are slower to develop, with clumps that are
  smaller and have a stringy consistency.
• A tube coagulase test should be ran on all
  presumptive S. aureus that give a negative
  Protein A test.

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Other S. aureus Characteristics

• Mannitol fermentation is another useful
  characteristic it is unique to, and consistent
  among S. aureus strains. Virtually all strains
  of S. aureus ferment mannitol.
• Bright yellow colonies on a yellow background
  indicates mannitol fermentation on mannitol salt
  agar.

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Other S. aureus Characteristics

• Another characteristic of most S. aureus cultures
  is the production of a heat stable enzyme that
  hydrolyzes RNA or DNA - a nuclease.
• Nucleases are heat stable, able to withstand 15
  minutes of boiling water. Testing to see if the
  boiled growth medium contains an active enzyme
  that hydrolyzes DNA or RNA is called a
  thermonuclease test
• Nucleases that may be produced by most
  Staphylococcus species other that S. aureus are
  not stable after boiling (if they do produce a
  nuclease it is not resistant to heat)

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S. aureus diagnosis - summary

• Clinical samples rarely contain pure cultures -
  should be assumed mixed. For this reason,
  culture on a selective medium for Gram positive
  bacteria such as Mannitol salt agar (MSA) or
  Colistin-Nalidixic Acid Agar (CNA).
• MSA notice growth and agar turns yellow around
  colonies.
• Also conduct primary culture on sheep blood agar
  (SBA). See colonies that progress from small,
  covex and off-white to larger flatter opaque
  porcelain golden yellow colonies. Notice beta
  hemolysis.
• Innoculate plate by rolling swab (if culture is
  on swab) on surface of agar in the first
  quadrant, then streak the remaining quadrants for
  isolation with loop. Incubate 35oC for 24 hours.
• Preliminary ID catalase positive, gram-positive
  coccus in tetrads and clusters.
• Additional characteristic behavior on media and
  positive coagulase test. Can also use automated
  ID system and serological methods.

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Pathology - predisposing factors

• This list is virtually true for all pathogens
• Immune system suppressed or otherwise
  compromised. Specifically
• Skin injuries (e.g. burns, surgical incisions,
  cuts, etc)
• Presence of foreign bodies (e.g intravenous
  lines, prosthetic devices, sutures, tampons-TSS)
• Pre-existing infections
• Chronic underlying conditions (e.g. auto-immune
  conditions, malignancies, alcoholism, heart
  disease, etc.)
• Compromised microbiota via antimicrobial therapy
• Infants susceptible oral, skin impetigo,
  scalded skin, respiratory, other

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S. aureus is a problem

• S. aureus has been generally considered the 1
  human pathogen since the 1980s.
• Why
• It is everywhere
• Nosocomial big problem in hospitals
• Antibiotic resistance 25 increase in MRSA
  isolates from 87-97 ONLY resistant to
  vancomycin
• Lots of toxins
• Good at immune evasion, rapid growth spread
  bacteremia
• Numerous types of infections

43
Upper respiratory tract

• Many bacterial species and viruses alike cause
  some manner of upper respiratory tract (URT)
  infection.
• S. aureus URT infection is fairly common with
  strep throat-like symptoms. Can co-reside with
  S. pyogenes or respiratory viruses such as
  influenza or RSV. Often causes secondary
  infections following respiratory viral infection.
• Uncommon cause of accute sinusitis and otitis
  media

44
Lower respiratory tract

• S. aureus is an uncommon cause of community
  acquired pneumonia (both primary and secondary)
  which is a lower respiratory tract (LRT)
  condition, although nosocomial cases are not
  uncommon. In fact, a CDC study in 1990 said S.
  aureus was the 1 cause of nosocomial pneumonia!
  
• These cases have a high mortality rate due to the
  immune compromised status of the patient, and
  high degree of antibiotic resistance of strains
  in the hospital. Comments made above about S.
  aureus co-residing and secondary infections apply
  here as well.
• Over 50 of community acquired typical
  bacterial pneumonias are caused Streptococcus
  pneumoniae - 1 cause

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Lower respiratory tract

• It is sometimes difficult to establish the cause
  of an LRT without the use of an invasive
  procedure because so many species of bacteria are
  picked up from the URT.
• Non-bacterial LRTs
• viruses are not an infrequent cause of LRTs
• fungal pathogens, especially Aspergillus sp,, and
  Pneumocystis carinii are found in
  immuno-compromised patients

46
Integument / wounds

• S. aureus is a common resident of the skin and
  exposed mucus membranes respiratory,
  genitourinary gastrointestinal.
• S aureus is the most common cause of pathogenic
  integument infection in humans.
• S. aureus is the 1 cause of post-operative
  infection, whether it be introduced during the
  course of the operation or afterward. These
  initial infections often become systemic and have
  high mortality rates

47
Integument / wounds

• Less severe integumentary cases include styes,
  pimples, folliculitis, and other localized
  absecces.
• Folliculitis (infected hair follicles) can become
  more deep seated causing a furuncle (a.k.a.
  boil). Multiple furuncles coalesce into a
  carbuncle. In severe, case S. aureus can spread
  hematogenously from here to any body site.
• S. aureus S. pyogenes cause impetigo, the most
  common skin infection in children highly
  contagious
• Also causes scalded-skin syndrome (Ritters
  syndrome) in infants via production of an
  exfoliating toxin fairly rare, at least in US

48
Food poisoning

• S. aureus is the 1 most common cause of food
  poisoning although it is comparatively mild in
  most cases.
• Symptoms include nausea, vomiting, diarrhea,
  abdominal cramping and mild fever.
• Symptom onset can be within minutes or hours of
  ingestion, with similar duration
• Foods handled foods wet, sugary or salty,
  handled after some preparation cooked, mixed,
  then served cold, at least initially

49
S. aureus other pathology

• S. aureus is the classic cause of toxic shock
  syndrome, a highly acute and highly toxigenic
  condition super-infection super-antigens
  result in organ destruction, shock, hypotension
  and death
• Acute or chronic osteomylitis, mainly in children
  
• Endocarditis
• Septic arthritis
• Mastitis
• Meningitis
• Phlebitis / thrombophlebitis (clotting)

50
Virulence Factors of S. aureus

• S. aureus possesses many properties that
  contribute to its ability to cause disease
• Not all strains of S. aureus possess all of these
  virulence factors but most possess several
• Capsule Like many strains of S. epidermidis, S.
  aureus produces a slime layer that adheres firmly
  to plastic prosthetic devices like catheters,
  shunts, and plastics bags used for continuous
  ambulatory peritoneal dialysis (CAPD). Capsules
  are also anti-phagocytic

51
Virulence Factors of S. aureus

• Protein A because protein A binds to the Fc
  fragment of IgG, this can interfere with IgGs
  ability to function as an opsonin (initiate
  phagocytosis) ie protein A is also
  anti-phagocytic
• Protein A also prevents IgG from activating
  complement thus preventing its various
  antimicrobial activities (e.g. complement
  mediates cytolysis, immune adherence, and
  initiation of inflammation)
• Teichoic acids in the cell wall of S. aureus also
  inhibits complement activation

52
Virulence Factors of S. aureus

• Enzymes/toxins contribute to its virulence
• Beta hemolysin
• Coagulase hide
• Staphylokinse (fibrinolysin) escape
• Leukocidin destroy PMNs
• Hyaluronidase get between cells
• Nucleases, phospolipases, proteases
• Antibiotic-ases
• ex. Penicillinase
• and more..

53
VF more enzymes / toxins

• Various other S. aureus exotoxins
• Enterotoxins work mainly on small intestine
  result in active transport of ions diarrhea
• TSST-1 also called superantigen, is pyrogenic
  and results in release of cytokines that are
  strongly vasoactive vessel damage leaking
  dramatic BP drop organ failure
• Exfoliating toxins
• others

54
Antimicrobial Susceptibility

• Penicillin resistance (possession of
  penicillnase) is coded on a plasmid the enzyme
  is also known as beta-lactamase inactivates the
  beta-lactam ring of penicillins and other
  beta-lactam antibiotics such as the
  cephalosporins
• Semi-synthetic drugs (modified penicillins) such
  as methicillin and oxacillin were developed for
  treating beta lactamase positive S. aureus
  infections
• Some strains are now resistant to these drugs
  MRSA, etc. A recent survey indicated that as
  many as 34 of S. aureus isolates were MSRA.

55
Antimicrobial Susceptibility

• MRSA is not only resistant to methicillin and
  most other penicillins and cephalosporins, but
  they are often resistant to almost all other
  antibiotics except vancomycin
• Although vancomycin is the drug of choice for
  treating MRSA infections, there are now
  vancomycin resistant (VRSA) S. aureus strains.
  The first VRSA strain was identified in Japan in
  1997, and 8 cases were confirmed in the US in
  2002.

56
Antimicrobial Susceptibility

• A high percentage of CoNS are also resistant to
  methicillin. Even though these isolates may be
  responsible for a variety of infections,
  methicillin resistant varieties are no more
  likely to be associated with nosocomial
  infections than are methicillin sensitive
  isolates.
• Hospital and nursing home epidemiological
  surveillance programs are routinely conducted for
  MRSA but NOT for methicillin resistant coagulase
  negative staphylococci

57
Coagulase Negative Staphylococcus

• Coagulase negative staphylococci (CoNS) are
  generally less virulent that S. aureus
• CoNS are inherently difficult to speciate even
  using modern clinical products and methods
• Unless a CoNS isolate is cultured repeatedly from
  a normally sterile body site (e.g.blood, CSF),
  identification to species level is usually not
  attempted
• Isolates that must be definitively identified to
  species level are sent to reference labs

58
CoNS S. epidermidis

• The most common CoNS species in clinical samples
  is S. epidermidis, comprising 50-80 of these
  isolates.
• S. epidermidis can be presumptively
  differentiated from other Staph species on the
  basis of the following observations
• It does not ferment mannitol or trehalose
• Coagulase negative
• It is sensitive to novobiocin
• It is resistant to polymyxin B
• Pathology of S. epidermidis is alsmost
  exclusively associated with skin penetration in
  the hospital setting

59
CoNS S. epidermidis

• S. epidermidis produces a capsule that adheres to
  plastic devices such as intravenous catheters,
  prosthetic heart valves, and shunts
• S. epidermidis and other CoNS are cause of native
  valve endocarditis

60
CoNS S. saprophyticus

• Staphylococcus saprophyticus is a CoNS associated
  with urinary tract infections, mostly in
  females, especially college age women
• S. saprophyticus is one of the few frequently
  isolated CoNS that is resistant to Novobiocin
• Novobiocin resistant staphylococci causing
  significant bacteruria can be presumptively
  identified as S. saprophyticus

61
Coagulase Negative Staphylococcus

• Following S. epidermidis and S. saprophyticus, S.
  hemolyticus, S. schleifferi and S. lugdunensis
  are the next most commonly isolated clinically
  significant CoNS ????
• The PYRase test is a test that can aid in
  differentiating S. hemolyticus, S. schleifferi
  and S. lugdunensis (PYRase positive) from other
  staphylococci.

62
Micrococcus species

• Micrococcus colonies are highly convex, yellow,
  not as glistening as Staph, and usually not as
  large as those of Staph
• Microscopically individual Micrococcus cells are
  somewhat larger than staphylococci and the
  predominant spatial arrangement is tetrads
• Tetrads and pairs of cells can set adjacent to
  form right angle geometric patterns like dominos

63
Micrococcus species

• Refer to slide 21 of this Power Point for a few
  tests used in differentiating the three genera of
  the Micrococcaceae.
• Being obligate aerobes, Micrococcus species
  produce acid only in the open tube (O tube O
  reaction) of the Oxidation/Fermentation test
  medium.

64
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65
Rothia mucilaginosus

• Rothia mucilaginosus is most abundant in the oral
  cavity
• Microscopically Rothia species form short chains
  and small clusters. Here, the longer axes are
  perpendicular rather than parallel
• The texture of R. mucilagenosus colonies is
  unique
• When pressure is applied using a loop, needle, or
  wooden applicator stick, R. mucilagenosus adheres
  tenaciously to the agar surface
• When further pressure is applied the upper
  portion of the colony peels off leaving the
  bottom portion sticking to the agar surface
• The most reliable test for differentiating R.
  mucilaginosus from staph and micrococci is strict
  salt sensitivity on salt agar (e.g.5-7.5 NaCl)
  such as mannitol salt agar. Micrococcus doesnt
  grow well, but it grows a little bit.

66
Presumptive Genus Identificationtable not on test
6.5 Furazoli- Modified 0.04 U
Salt done oxidase
Bacitracin Micrococcus R
S Staphylococcus S -
R R. mucilaginosa - NT NT
NT