Fourth generation fluoroquinolones: new weapons in the arsenal of ophthalmic antibiotics.
OBJECTIVE
Fourth generation fluoroquinolones (FQs) will soon be introduced to ophthalmology. In this in vitro study, differences in the susceptibility patterns and the potencies of fourth generation FQs (gatifloxacin-GAT and moxifloxacin-MOX) were compared with third generation (levofloxacin-LEV) and second generation FQs (ciprofloxacin-CIP and ofloxacin-OFX).


METHODS
Experimental laboratory investigation.


METHODS
In retrospect, the minimum inhibitory concentrations (MICs) of 93 bacterial endophthalmitis isolates were determined to CIP, OFX, LEV, GAT, and MOX using E-tests. The National Committee of Clinical Laboratory Standards (NCCLS) susceptibility patterns and the potencies of the MICs were statistically compared.


RESULTS
With in vitro tests, Staphylococcus aureus isolates that were resistant to CIP and OFX were statistically most susceptible (P =.01) to MOX. Coagulase negative Staphylococci that were resistant to CIP and OFX were statistically most susceptible (P =.02) to MOX and GAT. Streptococcus viridans were more susceptible (P =.02) to MOX, GAT, and LEV than CIP and OFX. Streptococcus pneumoniae was least susceptible (P =.01) to OFX compared with the other FQs. Susceptibilities were equivalent (P =.11) for all other bacterial groups. In general, MOX was the most potent FQ for gram-positive bacteria (P =.05) while CIP, MOX, GAT, and LEV demonstrated equivalent potencies to gram-negative bacteria.


CONCLUSIONS
This in vitro study indicated that fourth generation FQs appear to cover bacterial resistance to the second and third generation FQs, were more potent than the second and third generation FQs for gram-positive bacteria, and are equally potent for gram-negative bacteria. Clinical studies will need to confirm these results.
Mather
Rookaya
R
Charles T. Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Karenchak
Lisa M
LM
Romanowski
Eric G
EG
Kowalski
Regis P
RP
D000890:Anti-Infective Agents / Q000494:pharmacology*; D001372:Aza Compounds; D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D002939:Ciprofloxacin / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D009877:Endophthalmitis / Q000382:microbiology; D015818:Eye Infections, Bacterial / Q000382:microbiology; D024841:Fluoroquinolones; D000077734:Gatifloxacin; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D015242:Ofloxacin / Q000494:pharmacology; D011804:Quinolines; D012189:Retrospective Studies
D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin; D000077734:Gatifloxacin; D000077266:Moxifloxacin