Download Ocular Antibiotics and Anti-infectives

Ocular Antibiotics
and Anti-Infectives
Regis P. Kowalski, MS, M(ASCP)
Research Professor of Ophthalmology
Executive Director of The Charles T
Campbell Laboratory
University of Pittsburgh, Pittsburgh, PA
The Charles T. Campbell
Ophthalmic Microbiology
Laboratory
Areas of Infection
Normal Flora
Streptococcus
Coagulase-negative staphylococcus
Diphtheroids
Staphylococcus aureus
Gram negatives
No growth
60
Percent Incidence
50
40
30
20
10
0
Newborns
Children
Adults
Distribution of Bacteria Isolated from Endophthalmitis
(1993-2010) (N=518)
Gram-positives = 92.5%
Gram-negatives = 7.5%
Coagulase Negative
Staphylococcus
57.7% (299)
Streptococcus
species - 19.5% (101)
Other Gram
Negatives - 7.5% (39)
Other Gram
Positives - 4.8% (25)
Staphylococcus aureus - 10.5% (54)
Treatment Administration

Topical – Most common (conjunctivitis,
keratitis, blepharitis, prophylaxis)

Intra-vitreal injection – endophthalmitis

Systemic – not commonly used

Subconjunctival – used to provide a
constant flow of anti-infective to ocular
surface.
Antibacterials



Antibiotics – No Topical Standards for
Interpreting Susceptibility
Use Serum Systemic Susceptibility Standards But we must assume that “The antibiotic
concentrations reached in the ocular tissue by
topical therapy is equal to or greater than the
concentration of antibiotic in the blood serum”.
Ocular antibiotics are developed from systemic
antibiotics for conjunctivitis, keratitis
Antibiotics Parameters





Concentration–dependent
fluoroquinolones, aminoglycosides
Time-dependent
vancomycin, cefazolin
Bactericidal – kill
FQs, vancomycin,
Bacteristatic – inhibit
erythromycin, azithromycin, sulfa
Antiseptics – PI – kill immediately
Susceptibility Parameters
Death and NO mutations
MPC
Death but possible mutations
MBC
No growth but viable
MIC
Growth
Nature of Resistance of Bacteria




A function of the anti-infective
mechanism,
Target bacteria,
The ocular tissue, and
The treatment regimen.
Problem with Resistance



Organism acquires resistance to an
antibiotic.
Resistance spreads to other patients
No antibiotic to cover resistance
Class
Mode of Action
Fluoroquinolones
DNA synthesis
(ciprofloxacin, ofloxacin, bactericidal
levofloxacin, gatifloxacin,
moxifloxacin) besifloxacin
Primary Indication
besides conjunctivitis
keratitis, surgical prophylaxis
Broad-spectrum coverage
Aminoglycosides
(gentamicin, tobramycin,
amikacin)
protein synthesis keratitis, endophthalmitis
cell wall
surgical prophylaxis
bactericidal
Broad-spectrum coverage
Cephalosporins
(cefazolin, ceftazidime)
cell wall
bactericidal
keratitis, endophthalmitis
Gram-positive coverage
Glycopeptides
(vancomycin)
cell wall
bactericidal
keratitis, endophthalmitis
MRSA prophylaxis
Gram-positive coverage
Macrolides
(erythromycin, azithro)
protein synthesis blepharitis
bacteristatic
Gram-positive coverage
Peptides
(bacitracin, polymycin B)
cell wall
bactericidal
Sulfa drugs
(sulfacetamide)
enzyme inhibitor keratitis, 2nd – line MRSA
bacteristatic
Broad-spectrum coverage
blepharitis, keratitis
Bac – GMpos PB – GMneg
Anti-Infective Test Batteries
Keratitis
bacitracin
vancomycin
ciprofloxacin
ofloxacin
polymyxin B
cefazolin
tobramycin
sulfisoxazole
cefoxitin
gentamicin
gatifloxacin
moxifloxacin
Endophthalmitis
vancomycin
gentamicin
ciprofloxacin
ofloxacin
cefazolin
amikacin
ceftazidime
cefoxitin
ampicillin
clindamycin
gatifloxacin
moxifloxacin
Conjunctivitis
bacitracin
erythromycin
gentamicin
ciprofloxacin
ofloxacin
trimethoprim
polymyxin B
tobramycin
sulfisoxazole
azithromycin
gatifloxacin
moxifloxacin
Antifungal Drugs
Acanthamoeba Drugs


Cationic Antiseptics (Chlorhexidine
and PHMB)
Aromatic diamides (propamidine)
Thank You !!