Identification and antibiotic susceptibility of coagulase negative staphylococci isolated in corneal/external infections.
OBJECTIVE
To identify and determine antibiotic susceptibility of coagulase negative staphylococci (CoNS) isolated from patients with chronic blepharitis, purulent conjunctivitis, and suppurative keratitis.


METHODS
A retrospective review of all culture positive cases of chronic blepharitis, purulent conjunctivitis, and suppurative keratitis between July 1995 and December 1996 was performed. Cases in which CoNS were the sole isolates were analysed. Species identification was performed by using a commercially available standardised biochemical test system. Antibiotic susceptibility to penicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, and teicoplanin was determined by agar disc diffusion (Kirby-Bauer method). Teicoplanin resistance was confirmed by agar dilution.


RESULTS
42 Staphylococcus epidermidis, four S warneri, three S capitis, two S hominis, one each of S xylosus, S simulans, S equorum, and S lugdunensis were identified. 37 CoNS were penicillin resistant, 12 gentamicin resistant, 28 tetracycline resistant, 18 erythromycin resistant, four ciprofloxacin resistant, and one teicoplanin resistant (MIC, 32 microg/ml). In total, 16 strains were resistant to three or more antibiotics.


CONCLUSIONS
Species of CoNS apart from S epidermidis may be isolated from patients with corneal and external infection. Antibiotic susceptibility of CoNS is unpredictable and multiresistant strains are common. As a result, antibiotic susceptibility testing should be performed in all cases of clinically significant ocular infections caused by CoNS.
Pinna
A
A
Institute of Ophthalmology, University of Sassari, Sassari, Italy.
Zanetti
S
S
Sotgiu
M
M
Sechi
L A
LA
Fadda
G
G
Carta
F
F
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001762:Blepharitis / Q000188:drug therapy / Q000382:microbiology; D003234:Conjunctivitis, Bacterial / Q000188:drug therapy; D004352:Drug Resistance, Microbial; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000382:microbiology; D005839:Gentamicins / Q000627:therapeutic use; D006801:Humans; D007634:Keratitis / Q000188:drug therapy / Q000382:microbiology; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013753:Tetracycline Resistance
D000900:Anti-Bacterial Agents; D005839:Gentamicins