CN1: Integumentary System (Bacterial infections) Flashcards
1
Q
Honey-colored, thin, friable crust spreading peripherally with central clearing
A
Staphylococcus aureus infxn
2
Q
Predisposition to infection:
A
- Chronic S. aureus carrier state (nares, axilla, perineum, vagina)
- Warm weather/climate, high humidity
- Skin disease, especially atopic dermatitis, familial pemphigus
- Social situation: poor hygiene, crowded living conditions, neglected minor trauma
- Chronic disease: obesity, diabetes mellitus, HIV/AIDS
- Immune deficiency: cancer, chemotherapy
- Pre existing tissue injury or inflammation (surgical wound, burn, trauma, retained foreign body)
3
Q
What is a nonmotile coccus, 0.8 to 1.0 um in diameter, that divides into three planes?
A
Staphylococcus aureus
- irregular clusters or in short chains
4
Q
What are found characteristically in smears from cultures grown on solid media, whereas in broth cultures short chains and diplococcal forms are common?
A
Staphylococcus aureus
5
Q
In a few strains of S. aureus, what enhances the virulence of the organisms?
A
capsule or slime layer
6
Q
The cell wall of S. aureus consists of three major components:
A
- peptidoglycan
- teichoic acids
- protein A
7
Q
What is a facultative anaerobic but growth is more abundant under aerobic conditions?
A
S. aureus
8
Q
Growth occurs over a wide temperature range from 6.5C to 46C, with an optimum for S. aureus of _______.
A
30C to 37C
optimum temperature
9
Q
What is the pH optimum of S. aureus with growth occurring over a range of pH 4.2 to 9.3?
A
7.0 to 7.5
optimum pH
10
Q
Staphylococci grow well on most routine laboratory media such as
A
nutrient agar or trypticase soy agar
11
Q
For primary isolation from clinical materials, what is recommended?
A
Sheep blood agar
12
Q
On agar plates colonies, Staphylococcus aureus are:
A
smooth, opaque, round, low-convex, 1 to 4mm in diameter
on primary isolation: golden yellow colonies
13
Q
The color can be attributed to _________________
A
Carotenoid pigments
extremely variable ranging from deep orange to pale yellow
14
Q
What is the most convenient and reliable property for diagnostic purposes?
A
Coagulase - test tube method
an enzyme that cause the coagulation of plasma
15
Q
What is useful for screening purposes and usually, correlating well with test tube results, detects a clumping factor in the surface of an organism that is distinct from the free coagulase?
A
Slide test
16
Q
What is less reliable than the test tube method?
A
Slide test
17
Q
What is a crucial factor in determining the initiation and the outcome of
staphylococcal infections?
A
Phagocytic response
18
Q
Major determinants
A
In this process of host recognition and immunity, the cellular antigens of the staphylococcal cells, especially the surface ones
19
Q
Antigenic structures and virulence factors of S. aureus:
A
- Teichoic Acid
- Protein A
- Peptidoglycan
- Clumping Factor
- Capsular Polysaccharide
- Polysaccharides
- Hyaluronidase
- Staphylokinase (Fibrinolysin)
- Nuclease
- Cytolytic Toxins
- Protein Receptors
- Enterotoxins
20
Q
A major antigenic determinant of all strains of S. aureus is the group-specific ____ of the cell wall
A
Ribitol Teichoic Acid
21
Q
What is the serologic determinant of this polysaccharide (teichoic acid)?
A
N-acetylglucosamine
22
Q
What is not found in S. epidermis, which contains instead glycerol teichoic acid?
A
Ribitol teichoic acid
23
Q
In the CW, TA is associated with peptidoglycan in an insoluble state, and requires ________ for its release.
A
Lytic enzymes
24
Q
Most adults have a this type of reaction to teichoic acid, and low levels of precipitating antibodies are found in their sera.
A
cutaneous hypersensitivity reaction of the immediate type
25
Elevated levels of teichoic acid antibodies can result from:
staphylococcal disease, such as *endocarditis* or *bacteremia*
| with metastatic foci of abscesses in which **drainage or antibiotic ther
26
What are infrequent in transient staphylococcal bacteremia?
Increases in teichoic acid antibodies
27
What is responsible for the rapid consumption of early-reacting complement components up to and including C5 in human serum?
Extracellular teichoic acid
28
What occurs as a consequence of *immune complex formation* between the antigen and specific human IgG antibodies?
Complement activation
29
What is found in the cell wall covalently linked to the peptidoglycan?
Protein A
| is a group-specific antigen unique to S. aureus strains.
30
By induction of abortive, complement-consuming reactions, what ***protects*** staphylococci from complement-dependent opsonization?
Teichoic acid
31
```
Virtually all healthy donors have antibodies to the __________ in their serum. They are primarily of the IgG class and can cross the placenta.
```
peptidoglycan
32
What elicits both *humoral* and *cellular* immune responses?
Staphylococcal peptidoglycan
33
Peptidoglycan are primarily of what immunoglobulin class?
IgG
34
What can cross the placenta?
IgG
35
What *increases the antipeptidoglycan IgG* level especially when accompanied by a **bacteremic phase**?
S. aureus infections
36
What are potentially beneficial because of their opsonizing capacity, increased levels may predispose some patients to immune complex disorders?
Ab
37
The component on the cell wall of S. aureus that results in the clumping of whole staphylococci in the *presence of plasma* is referred to as the
Clumping factor
| S. aureus expresses surface receptors for ***fibrinogen***
38
Clumping factor binds ____ and differs from free coagulase in both its mechanism of action and its antigenic properties.
human fibrinogen
39
What is found almost exclusively in strains that produce the extracellular coagulase?
Cellular fibrinogen – binding component
40
What can give a negative clumping reaction, presumably because the clumping factor is covered by extracellular polysaccharides?
Encapsulated strains
41
When tested with ____, most strains isolated from clinical material are found to carry immunologically significant polysaccharide surface antigens.
monospecific antisera
42
What is a characteristic of a capsular polysaccharide?
Antiphagocytic
43
They interfere with the interaction between the underlying teichoic acid – peptidoglycan complex and complement, which is activated primarily through the ***alternative pathway***.
Capsular Polysaccharide
| these antigens are antiphagocytic
44
What encodes proteins involved in antibiotic resistance and other virulent factors?
Plasmids
45
S. aureus expresses surface receptors and uses these molecules as a bridge to bind to host endothelial cells:
- Fibrinogen (called
clumping factor)
- Fibronectin
- Vitronectin
46
What has a polysaccharide capsule that allows them to attach to the artificial materials and to resist host cell phagocytosis?
Staphylococci infecting *prosthetic valves
and catheters*
47
What degrades lipids on the skin surface, and its expression is correlated with the ability of the bacteria to produce ***skin abscesses***?
Lipase of S. aureus
48
Staphylococci also have *protein A* on their surface which binds in what portion of the Ig?
Fc
49
What is the pore-forming protein that intercalates into the plasma membrane or host cells and depolarizes them?
a-toxin
| - a damaging hemolytic toxin
50
What is a sphingomyelinase?
B-toxin
51
What is a detergent-like peptide?
delta-toxin
52
Toxin on: Erythrocytes
Staphylococcal gamma-toxin
53
Toxin on: Phagocytic cells
Leukocidin
54
What is produced by S. aureus are *serine proteases* that split the skin by cleaving the protein **desmoglein 1** which is part of the desmosomes that hold epidermal cells tightly together?
Exfoliative toxins
55
What can cause the superficial epidermis to split away from the deeper skin, making the patient vulnerable to secondary infections?
Exfoliative toxins
56
Exfoliation can occur at the site of what?
Staphylococcal skin infection (bullous impetigo)
57
What can be widespread when secreted toxin from a localized infection causes disseminated loss of the superficial epidermis?
Staphylococcal scalded-skin syndrome
58
What are the enzymes facilitating establishment of the organism on the skin and mucous membranes of the host?
Proteases
Lipases
Esterases
Lyases
59
By protecting the organisms from the complement-mediated attack of polymorphonuclear leukocytes, *encapsulated staphylococci* are able to what?
Spread rapidly through tissues
60
For colonization to occur, however, and the infectious process to be sustained, what is the essential initiating event?
***Adhesion*** of the organisms to a biosurface
61
What enzyme hydrolyzes the hyaluronic acid present in the intracellular ground substance of connective tissue, thereby facilitating the spread of the infection?
Hyaluronidase
| 90% in S. aureus
62
The determinant for staphylokinase/fibrinolysin production is dependent on what?
A phage genome
| and is expressed during *lysogeny*
63
In the dissolution of clots by the staphylococcal enzyme, what proenzyme is converted to the fibrinolytic enzyme plasmin?
Plasminogen
64
The enzyme, which is present in, at, or near the cell surface, is a ***compact globular protein***
consisting of a *single polypeptide chain*.
Nuclease
65
What is among the best defined of the cytolytic toxins, a group of toxins that also includes streptolysin O and S and various toxins of Clostridium?
Hemolysins and leukocidin
66
What are produced by S. aureus, although strains may vary in the levels that they express?
Four distinct hemolytic toxins (a-, B-, d-, y-hemolysins)
67
These receptors provide the organism with an *adhesion* mechanism by which infective foci become established.
Protein Receptors
68
What are the plasma proteins that bind specifically to S. aureus?
fibronectin, fibrinogen, IgG, and C1q
69
Staphylococci also bind to components of what matrix?
```
Extracellular matrix (e.g., laminin, collagen, and
fibronectin)
```
70
What exotoxins are members of a large group of pyrogenic protein toxins that mediate a spectrum of diseases with similar clinical manifestations and organ involvements?
Enterotoxins
| 1/3 S. aureus isolates produce exotoxins
71
What are the causes and manifestations of Staph infection?
- Respiratory infection
- Wound infxn
- Impetigo
- Focal skin infxns (abscess, furuncle, carbuncle)
- Endocarditis
- Food poisoning
- Toxic shock syndrome
72
Presumptive test/evidence of staphylococci:
typical irregular clusters of G (+) cocci on direct exam of purulent material
73
Staph infection: Definitive identification requires laboratory isolation of what?
*pus, purulent fluids* should be streaked directly on a *blood agar plate* and inoculated into a tube of *thioglycollate broth*
74
What are small to medium; translucent, gray-white colonies, most colonies nonhemolytic?
| on 5% sheep blood agar
Staphylococcus epidermidis
75
What have slime-producing strains are extremely sticky and adhere to agar surface?
Staphylococcus epidermidis
76
What enhances organism adhesion and provides mechanical barrier to antibiotics and host defense mechanism?
Production of exopolysaccharide “slime” or biofilm
77
What are normal flora of human skin and mucous membranes; distributed widely, often in large numbers over body surface?
Staphylococcus epidermidis
78
What are the key determinants of S. aureus when you distinguish them from S. epidermidis based on biochemical properties?
S. aureus in Coagulase, Anaerobic growth and fermentation of glucose, Mannitol – acid anaerobically, a-toxin, Heat resistant endonucleases, Ribitol, and Protein A are ALL POSITIVE.
S. au is NEGATIVE in Biotin required for growth and Glycerol
79
What are the differences key determinants of S. epidermidis when you distinguish them from S. aureus based on biochemical properties?
S. epidermidis in Anaerobic growth and fermentation, Biotin required for growth, and Glycerol are ALL POSITIVE.
S. epi is NEGATIVE in Coagulase, Mannitol – acid anaerobically, a-toxin, Heat resistant endonucleases, Ribitol, and Protein A.
80
The only same biochemical properties that both S. aureus & S. epidermidis are positive:
Anaerobic growth and fermentation of glucose
81
What are less virulent than S. aureus and are *opportunistic*?
Staphylococcus epidermidis
82
What is S. epidermidis in coagulase test?
Negative
83
What include nosocomial bacteremia associated with *indwelling vascular catheter*: **endocarditis** involving *prosthetic cardiac valves*?
Staphylococcus epidermidis
84
Tend to be non – hemolytic; and cause disease in immunosuppressed persons
Staphylococcus epidermidis
85
The sequence of spread of S. aureus is from
*nose to normal skin* (about 11 days later) and *skin lesions* (after another 11 days)
86
What are spherical to ovoid organisms, 0.5 to 1.0 um in diameter?
S. pyogenes (group A B-Hemolytic Strep.)
| G (+) cocci, pairs or chains
87
What is the preferred culture media for primary isolation of Group A streptococci?
Sheep blood agar (or with blood products)
88
Why is it recommended that agar be slashed by the loop at the primary site of inoculation?
To ensure **subsurface** growth
| since hemolysis is enhanced under ***anaerobic*** conditions
89
S. pyogenes catalase test
Negative
90
What is the optimal pH or growth for Group A streptococci?
7.4 to 7.6 at 37C
91
What are gram positive and catalase negative?
Streptococci
92
This is specific to the species, and is composed of a branched polymer of *L-rhamnose and
N-acetyl-Dglucosamine* in **2:1** ratio, the latter being the antigenic determinant:
C-polysaccharide
93
What is linked by the phosphate-containing bridges to the peptidoglycan, which consists of N-acetlyl-D glucosamine, N-acetyl-D-muramic acid, D-glutamin acid, L-lysine, and D- and L-alanine?
C-polysaccharide
94
What does Group A streptococci produce which are two major classes of protein antigens that are responsible for type specificity in the group?
M and T antigens
| both are suff stable and immunologically distinct to provide Sero typing
95
What is resistant to heat and acid but is destroyed by trypsin?
M antigen
96
What is heat and acid stable but are resistant to trypsin?
T antigens
97
What is performed by **capillary tube precipitin tests using a hydrochloric acid** extract to harvested cells as an antigen against absorbed rabbit type-specific hyperimmune sera?
Routine M typing
98
For its expression, organisms should be grown on *media containing peptides*
M protein
99
To avoid destruction of the M protein by proteinase activity, the pH should **not** be allowed to fall below what?
Below 6.5
100
What is an *antiphagocytic fibrillar* molecule located on the surface of group A organisms?
Streptococcal M protein
101
What is a surface protein that prevents bacteria from being phagocytosed?
M protein
| expressed by S. pyogenes
102
What degrades this chemotactic peptide?
C5a peptidase
103
What is probably an autoimmune disease caused by antistreptococcal M protein antibodies that cross-react with *cardiac myosin*?
Poststreptococcal acute rheumatic fever
104
What has been referred to as *flesh-eating bacteria* because they cause a **rapidly progressive
necrotizing fasciitis**?
Virulent S. pyogenes
105
What is a cytosolic bacterial protein released on disruption of S. pneumoniae?
Pneumolysin
106
What inserts into target cell membranes and lyses them, greatly increasing tissue damage?
Pneumolysin
| activates the classical comp pathway, reducing the comp available for opso
107
What can secrete a phage-encoded pyrogenic exotoxin that causes *fever
and rash* in **scarlet fever**?
Streptococci
108
What produces *caries* by metabolizing **sucrose to lactic acid** (which causes demineralization of tooth enamel) and by secreting high-molecular-weight glucans that promote aggregation of bacteria and plaque formation?
S. mutans
109
It has been shown that adherence to ***buccal epithelial cells*** is mediated by
Lipoteichoic Acid
110
What is an is amphipathic, highly cytotoxic, and amphoteric molecule? Also forms a complex network with M protein and binds via its lipid moiety to fibronectin on epithelial cells
Lipoteichoic Acid
111
Able to resist phagocytosis by killing leukocytes proliferate and begin to invade local tissues:
Organisms rich in M protein
112
The CW of group A streptococci have been shown to react with ________ in a nonimmune manner similar to that of staphylococcal protein A.
IgG
113
What has been attributed to the inhibition of complement, mediated by the binding of **factor H**, the serum control protein of the *alternative complement pathway*?
The antiphagocytic activity of streptococcal M protein
114
What is located on the cell surface, destroys chemotactic signals by removing a six-amino-acid peptide from the carboxyterminus of the complement component C5a?
C5a peptidase
115
What is the major virulence factor of group A streptococci and renders the
organisms **resistant to phagocytosis**?
M protein
116
What happens when there is the absence of type-specific Ab?
Streptococci producing M protein persists in infected tissues until Ab appear.
117
The antiphagocytic activity of M protein is attributed to an interference with the deposition of what?
Complement component C3b onto the streptococcal cell surface
118
What does many group A streptococci produce which mimics the ground substance of animal tissue?
Diffuse hyaluronic acid capsule
119
What is responsible for the clear zones of Beta-hemolysis around the colonies in BA media?
Hemolysins
120
What is an immunogenic single-chain protein (ca 60 kDa) released into the culture medium during growth?
STREPTOLYSIN O
121
It is the prototype of a group of **oxygen-labile** or ***thiol-activated*** bacterial cytolytic protein toxins produced by diverse species of Streptococcus, Bacillus, Clostridium, and Listeria.
STREPTOLYSIN O
122
Their toxins are inactivated irreversibly by cholesterol and structurally related sterols.
STREPTOLYSIN O
| G (+) and are immunologically cross-reactive
## Footnote
- their biologic and lethal effects are rapidly *lost* by **oxidation**
- but are completely *restored* by **thiols** or other reducing agents
123
The toxins SLO are inactivated irreversibly by:
**Cholesterol** also structurally related sterols
124
The toxins (SLO) bind to the membrane and oligomerize in the membrane to form:
Large arc- and ring- shape structures composed of 25-100 toxin monomers
125
What is an *oxygen-stable*, *nonantigenic* toxin that is extractable from streptococcal cells only when a carrier or inducer is added to the culture or to resting cell suspension?
STREPTOLYSIN S
126
SLS is ____ for RBC and WBC and also for wall-less forms (protoplasts and L-forms) from various species.
lytic
| lytic effects are inhibited by **phospholipids**, has cytolytic involvement
127
What is responsible for the *surface hemolysis* seen on blood agar plates?
STREPTOLYSIN S.
| occasional strains that lack SLS may appear nonhemolytic on surface growth
128
There are at least three different serotypes (A, B, and C), which have molecular weights of:
A: 8 kDa
B: 17.5 kDa
C: 13.2 kDa
129
What are *heat labile* but are **stable** to **acid, alkali, and pepsin**?
Pyrogenic Exotoxins (Erythrogenic Toxins)
| 90% of all grp A streptococci produce this
130
The structural gene for pyrogenic exotoxins in the case w diphtheria toxin, is carried by a:
Temperate bacteriophage
131
What causes **increased permeability of the blood-brain barrier** to endotoxin and bacteria and exerts its pyretic effect by direct action on the *hypothalamus*?
Type C toxin
132
What VF in S. pyo assist in the liquefaction of pus and preseumably help to generate substrates for growth?
Nucleases
| has 4 (A, B, C, D)
- all strains of S. pyo produce at least 1 nuclease,
133
Nucleases A and C have only what activity?
DNase activity
134
B and D also possess what?
RNase activity
135
After *18 to 24 hours* of growth on agar, their colonies are **0.5mm** in diameter, *doomed, grayish to opalescent*, and surrounded by a zone of B hemolysis several times greater than the diameter of the colony.
S. pyogenes
136
What is distinguished from *B-hemolytic* streptococci by a variety of
techniques such as **Lancefield extraction and precipitation, fluorescent antibody or coagglutination**?
Group A streptococci
| MoT: direct contact
137
Pathophysiology of the Infectious Process (Transient Stage)
1. S. aureus (most common) & group A beta-hemolytic strep.
2. Immunocompromised, Traumatized, Poor hygiene, Malnourished
3. Transient stage
4. Disruption of the integrity of epidermis (skin barrier) e.g. Alcohol spraying, insect bites, abrasion, maceration, shaving, chronic wounds
5. Pathogens invades skin
6. Produce infxn w vesicopustule formation just beneath the stratum corneum
138
The development and evaluation of bacterial infection involve three major factors:
1. The portal of entry
2. The host defenses and inflammatory response to microbial invasion – natural resistance of the skin
3. The pathogenic properties of the organism
138
What colonizes the skin shortly after birth?
Coagulase negative staphylococci
139
What is always caused by coagulase-positive S. aureus, group A Beta hemolytic streptococcus (GABHS) are implicated in the development of some lesion?
Bullous impetigo
140
Staphylococci generally spread from **nose to normal skin then infect the skin**.
In contrast, the skin becomes colonized with *GABHS an average of **10 days** *before development of ***impetigo***, GABHS then colonize the **nasopharynx** and average of ________ wks after the *appearance of lesions of impetigo*.
2-3 weeks
| skin - serves as a sources of acquisition of GABHS in the respi tract
## Footnote
also the probable primary source of spread of **impetigo**
141
Flat (Non palpable)
MACULE
PATCH
142
*various* sized, flat, even with the surface level of the skin, *circumscribed, is a change in the skin color without elevation or depression.*
MACULE
143
> 1cm, like a macule, flat area on skin or mucous membrane with a different color from surrounding areas.
-PATCH
144
Raised (Palpable)
PAPULE
PLAQUE
NODULE
145
Circumscribed, solid elevations w *no* visible fluid varying in size from *pinhead to 1 cm*
PAPULE
146
*Broad* papule (or confluence of papules) *1cm or > in diameter*, generally flat but maybe centrally depressed
PLAQUE
147
Is a palpable lesion greater than 1 cm with domed, spherical or ovoid shape. May be solid or cystic.
Have 5 main types:
1. Epidermal
2. Epidermal-dermal
3. Dermal
4. Dermal-sub-dermal
5. Subcutaneous
-NODULE
148
Fluid filled
VESICLES (Blisters)
BULLAE
PUSTULES
149
1-10mm well circumscribed fluid filled lesions, epidermal elevations. May have pale or yellow (from serous exudates) or red (serum + blood)
The wall is thin and translucent enough to visualize the contents, which may be clear, serous or hemorrhagic.
VESICLES (Blisters)
150
> 1cm Rounded or irregular shaped blisters containing serous or seropurulent fluid and larger than vesicles.
BULLAE
151
Well circumscribed, raised pus filled lesion arising from the epidermis or infundibulum. The *purulent exudate* may be white or yellow, composed of leukocytes with or without cellular debris, may contain organisms or may be sterile.
| 1-10mm
PUSTULES
152
SECONDARY CHANGES (Epidermal or surface change)
SCALES
CRUST (Scabs)
LICHENIFICATION
FISSURE
153
Macroscopic finding indicating a change in the epidermis. *Dry or greasy laminated
masses of keratin*, with varying sizes, may be *thick, fine, brawny, delicate*, greasy, micaceous.
SCALES
154
**Dried fluid** on the skins surface due to serum, *blood*, *pus* or a
combination.
CRUST (Scabs)
155
Is a thickening and accentuation of the skin lines that results from
repeated rubbing or scratching of the skin
-LICHENIFICATION
156
Is a linear loss of continuity of the skins surface or mucosa that results
from excessive tension
-FISSURE
157
= History of recent exposure to offending allergic agent
| = Affected area involved exposed to offending agent
Allergic contact dermatitis
158
= History of drug intake or recent herpes simplex infection prior to the appearance of lesions
= “Target lesions” – edematous looking, pale, erythematous macules
with a vesicle or erosion in the center surrounded by concentric rings
Erythema Multiforme
159
= History of recent burns
Thermal burns
160
= Involves primarily the feet
| = (+) fungal spores/hyphae on KOH
Bullous tinea pedis
161
= involves the head, beard, face and hands
| = (+) fungal spores/hyphae on KOH
Fungal – Tinea corporis – for non-bullous impetigo
162
S. aureus isolates from *impetigo, ecthyma and folliculitis* are more frequently caused by
methicillin-sensitive S. aureus
163
Systemic - Penicillinase resistant penicillin is the drug of choice because they are effective against penicillinase – producing Staphylococcus aureus.
Dicloxacillin, Cloxacillin, Oxacillin, Methicillin and Nafcillin
| Topical: Mupirocin ointment/cream
164
(adults: 300 to 450 mg 3 to 4 times a day;
| children: 20 to 40 mg/kg/day in 3-4 divided doses
Clindamycin
165
If CA-MRSA is suspected as the causative organism,
______ (Adults: 100 mg twice daily; Children: not
recommended for children younger than age 8 years),
______ (adults: 500 mg orally 4 times a day;
children 50 to 100 mg/kg/day divided 3 to 4 times
per day) is recommended.
Doxycycline
| Cephalexin
166
For patients allergic to penicillin or B-lactams, _________ could serve as a substitute (adults: 250 to 500 mg orally 4 times
a day; children: 40 mg/kg/day divided 3 to
4 times per day).
Erythromycin
167
Topical
1. Mupirocin 2% topical ointment
2. Retapamulin 1% ointment BID for 5-7 days or
3. Fusidic acid cream BID 5-7 days
168
Bactericidal drug.
It acts to *inhibit cell wall synthesis and growth*.
**Dicloxacillin** is the most active and most strains of S. aureus are inhibited by concentration of 0.05 to 0.8 ug / ml.
Pharmacodynamics
169
Rapidly but incompletely (30% to 40%) is absorbed from the gastrointestinal tract.
Absorption is more efficient when taken in an empty stomach and preferably when administered one hour or two hours after meals or ensure better absorption.
Oral dose of Dicloxacillin yields peak plasma concentration of **15 ug/mL by one hour**.
It is rapidly excreted by the kidneys.
The drug is excreted in the urine in the **first 6 hours** after a conventional oral dose.
Pharmacokinetics
170
Untoward effects
1. Hypersensitivity reactions are the most common adverse effects noted
with penicillins. The most serious hypersensitivity reactions produced by
penicillins are ***angioedema*** and ***anaphylaxis***.
Others include serum sickness, vasculitis of the skin, fever maybe the only
evidence of a hypersensitivity reaction to penicillins, eosinophilia is an
occasional accompaniment of other allergic reactions to penicillin.
2. Gastrointestinal disturbances such as nausea and diarrhea may occur
with oral penicllin.
171
Other effective alternative therapies (Systemic – 2nd line).
Erythromycin in the penicillin allergic patient
Amoxicillin plus clavulanic acid – for impetigo caused by erythromycin resistant
S. aureus
Cephalexin
Ceproxil
Clindamycin
Azithromycin
172
infection deeply penetrating the epidermis producing a shallow crusted ulcer
Ecthyma
173
Acute spreading inflammation involving deeper subcutaneous tissue
Cellulitis
174
Inflammatory condition involving subcutaneous lymphatic channels
Lymphangitis
175
Major serious sequelae 1
Acute poststreptococcal glomerulonephritis
| Secondary BI: ECLA, Bacteremia, Septicemia, Osteomyelitis, Pnemonitis
