Effect of sulfur hexafluoride gas on antibacterial activity of antibiotics in vitro against agents causing endophthalmitis.
BACKGROUND
We conducted a study to evaluate the effect of sulfur hexafluoride gas (SF(6)) on the antibacterial activity of antibiotics in vitro against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, which are common endophthalmitis-causing agents.


METHODS
In this experimental study, antibiotic susceptibility tests were prepared according to the National Committee for Clinical Laboratory Standards macrobroth dilution method. Müller-Hinton broth was the test medium. Standard P. aeruginosa (ATCC 27853), S. epidermidis (ATCC 12228) and S. aureus (ATCC 29213) strains were studied. For P. aeruginosa ceftazidime, ofloxacin and tobramycin dilutions, and for S. epidermidis and S. aureus, cefazolin, ofloxacin and tobramycin dilutions were prepared identically in two sets of tubes. One set of tubes, into which pure SF(6) was injected, was defined as the SF(6) group. The other set of tubes, into which no SF(6) was injected, was taken as the control group. To determine the minimal bactericidal concentrations of the antibiotics, subcultures were made onto Müller-Hinton agar, and the colonies were counted after 18 h of incubation at 37 degrees C.


RESULTS
The minimal inhibitory concentrations of the antibiotics in the SF(6) group were found to be identical with those of the control group. However, the minimal bactericidal concentrations of the antibiotics were found to be at least two dilutions lower in the SF(6) group than in the control group, except for the minimal bactericidal concentration of cefazolin for S. aureus, which was found to be one dilution lower in the SF(6) group.


CONCLUSIONS
SF(6) was found to potentiate the in vitro antibacterial activity of ofloxacin and tobramycin against S. aureus, S. epidermidis and P. aeruginosa, ceftazidime against P. aeruginosa, and cefazolin against S. epidermidis. Experimental animal studies are required to determine the role of SF(6) in the management of endophthalmitis.
Yanyali
A
A
Department of Ophthalmology, Kocaeli University, School of Medicine, Izmit, Turkey. ayanyali@hotmail.com
Cetin
S
S
Talu
H
H
Vahaboglu
H
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002437:Cefazolin / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology*; D004357:Drug Synergism; D009877:Endophthalmitis / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013212:Staphylococcus epidermidis / Q000187:drug effects*; D013459:Sulfur Hexafluoride / Q000494:pharmacology*; D014031:Tobramycin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D002511:Cephalosporins; D002442:Ceftazidime; D015242:Ofloxacin; D002437:Cefazolin; D014031:Tobramycin; D013459:Sulfur Hexafluoride