ocular antibiotics and anti-infectives regis p. kowalski, ms, m(ascp) research professor of...
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Ocular Antibiotics Ocular Antibiotics and Anti-Infectivesand 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 The Charles T. Campbell Ophthalmic Microbiology Ophthalmic Microbiology LaboratoryLaboratory
Areas of Infection
Per
cent
Inc
iden
ce
0
10
20
30
40
50
60
Newborns Children Adults
No growth
StreptococcusCoagulase-negative staphylococcusDiphtheroidsStaphylococcus aureusGram negatives
Normal Flora
Distribution of Bacteria Isolated from Endophthalmitis (1993-2010) (N=518)
Staphylococcus aureus - 10.5% (54)
Other GramPositives - 4.8% (25)
Streptococcusspecies - 19.5% (101)
Coagulase NegativeStaphylococcus 57.7% (299)
Other GramNegatives - 7.5% (39)
Gram-positives = 92.5%Gram-negatives = 7.5%
Treatment AdministrationTreatment Administration
Topical Topical – Most common (conjunctivitis, – Most common (conjunctivitis, keratitis, blepharitis, prophylaxis)keratitis, blepharitis, prophylaxis)
Intra-vitreal injectionIntra-vitreal injection – endophthalmitis – endophthalmitis
SystemicSystemic – not commonly used – not commonly used
SubconjunctivalSubconjunctival – used to provide a – used to provide a constant flow of anti-infective to ocular constant flow of anti-infective to ocular surface.surface.
AntibacterialsAntibacterials
Antibiotics – No Topical Standards for Interpreting Antibiotics – No Topical Standards for Interpreting SusceptibilitySusceptibility
Use Serum Systemic Susceptibility Standards - Use Serum Systemic Susceptibility Standards - But we must assume that But we must assume that “The antibiotic “The antibiotic concentrations reached in the ocular tissue by concentrations reached in the ocular tissue by topical therapy is equal to or greater than the topical therapy is equal to or greater than the concentration of antibiotic in the blood serum”.concentration of antibiotic in the blood serum”.
Ocular antibiotics are developed from systemic Ocular antibiotics are developed from systemic antibiotics for conjunctivitis, keratitisantibiotics for conjunctivitis, keratitis
Antibiotics ParametersAntibiotics Parameters
Concentration–dependentConcentration–dependent
fluoroquinolones, aminoglycosidesfluoroquinolones, aminoglycosides Time-dependentTime-dependent
vancomycin, cefazolinvancomycin, cefazolin Bactericidal – killBactericidal – kill
FQs, vancomycin,FQs, vancomycin, BacteristaticBacteristatic – inhibit – inhibit
erythromycin, azithromycin, sulfaerythromycin, azithromycin, sulfa AntisepticsAntiseptics – PI – kill immediately – PI – kill immediately
MIC
MBC
MPC
Growth
No growth but viable
Death but possible mutations
Death and NO mutations
Susceptibility Parameters
Nature of Resistance of BacteriaNature of Resistance of Bacteria
A function of the anti-infective A function of the anti-infective mechanism,mechanism,
Target bacteria,Target bacteria, The ocular tissue, and The ocular tissue, and The treatment regimen.The treatment regimen.
Problem with ResistanceProblem with Resistance
Organism acquires resistance to an Organism acquires resistance to an antibiotic.antibiotic.
Resistance spreads to other patientsResistance spreads to other patients No antibiotic to cover resistanceNo antibiotic to cover resistance
Class Mode of Action Primary Indicationbesides conjunctivitis
Fluoroquinolones DNA synthesis keratitis, surgical prophylaxis(ciprofloxacin, ofloxacin, bactericidal Broad-spectrum coveragelevofloxacin, gatifloxacin,moxifloxacin) besifloxacin
Aminoglycosides protein synthesis keratitis, endophthalmitis(gentamicin, tobramycin, cell wall surgical prophylaxisamikacin) bactericidal Broad-spectrum coverage
Cephalosporins cell wall keratitis, endophthalmitis(cefazolin, ceftazidime) bactericidal Gram-positive coverage
Glycopeptides cell wall keratitis, endophthalmitis(vancomycin) bactericidal MRSA prophylaxis
Gram-positive coverage
Macrolides protein synthesis blepharitis(erythromycin, azithro) bacteristatic Gram-positive coverage
Peptides cell wall blepharitis, keratitis(bacitracin, polymycin B) bactericidal Bac – GMpos PB – GMneg
Sulfa drugs enzyme inhibitor keratitis, 2nd – line MRSA(sulfacetamide) bacteristatic Broad-spectrum coverage
Anti-Infective Test BatteriesAnti-Infective Test Batteries
KeratitisKeratitis EndophthalmitisEndophthalmitis ConjunctivitisConjunctivitisbacitracinbacitracin vancomycinvancomycin bacitracinbacitracinvancomycinvancomycin gentamicingentamicin erythromycinerythromycinciprofloxacinciprofloxacin ciprofloxacinciprofloxacin gentamicingentamicinofloxacinofloxacin ofloxacinofloxacin ciprofloxacinciprofloxacinpolymyxin Bpolymyxin B cefazolincefazolin ofloxacinofloxacincefazolincefazolin amikacinamikacin trimethoprimtrimethoprimtobramycintobramycin ceftazidimeceftazidime polymyxin Bpolymyxin Bsulfisoxazolesulfisoxazole cefoxitincefoxitin tobramycintobramycincefoxitincefoxitin ampicillinampicillin sulfisoxazolesulfisoxazolegentamicingentamicin clindamycinclindamycin azithromycinazithromycingatifloxacingatifloxacin gatifloxacingatifloxacin gatifloxacingatifloxacinmoxifloxacinmoxifloxacin moxifloxacinmoxifloxacin moxifloxacinmoxifloxacin
Antifungal DrugsAntifungal Drugs
Acanthamoeba DrugsAcanthamoeba Drugs Cationic Antiseptics (Chlorhexidine Cationic Antiseptics (Chlorhexidine
and PHMB)and PHMB) Aromatic diamides (propamidine)Aromatic diamides (propamidine)
Thank You !!