Use of elemental iodine for shunt infection prophylaxis.
OBJECTIVE
Elemental iodine (I(2)) can kill a broad spectrum of organisms, including bacteria, fungi, and viruses. Furthermore, it is inexpensive, bacterial resistance is unknown, and allergic reactions are rare. Because of these properties, we wanted to determine the concentration of I(2) that would kill Staphylococcus epidermidis and Staphylococcus aureus without causing injury to the central nervous system, in an attempt to further reduce the rates of shunt infections.


METHODS
Bacterial kill studies using S. epidermidis and S. aureus were performed by using Ringer's lactate solution alone or solution containing I(2) at a concentration of 5, 10, 20, 50, 100, or 1000 parts per million (ppm), cefazolin at 1 mg/ml, or bacitracin at 100 units/ml. Twenty-one adult male Wistar rats, in seven groups, underwent a frontoparietal craniectomy. The surfaces of their brains were irrigated for 1 hour with Ringer's lactate solution alone or solution containing I(2) (at the concentrations noted above). After 72 hours of observation, the animals were killed. Their brains were then fixed in formalin, stained with hematoxylin/eosin, and examined.


RESULTS
Even with exposure of only 15 seconds to an I(2) solution of 20 ppm, no growth was detected with an inoculum of either bacteria of 100 million. In contrast, the two antibiotics were not nearly as effective as I(2), with kill rates ranging from 19 to 93%. Examination of the rat brains demonstrated no histological changes after subarachnoid exposure to solutions containing 5, 10, 20, or 50 ppm; however, necrosis was observed with concentrations of 100 and 1000 ppm.


CONCLUSIONS
I(2) can be added to irrigation solutions in sufficient concentrations to be bactericidal without causing any central nervous system injury.
Choi
SooHo
S
Division of Neurosurgery, Childrens Hospital of Los Angeles, CA 90027, USA.
McComb
J Gordon
JG
Levy
Michael L
ML
Gonzalez-Gomez
Ignacio
I
Bayston
Roger
R
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001414:Bacitracin / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000473:pathology; D002557:Cerebrospinal Fluid Shunts; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007455:Iodine / Q000494:pharmacology*; D007552:Isotonic Solutions / Q000494:pharmacology; D008297:Male; D008826:Microbial Sensitivity Tests; D051381:Rats; D017208:Rats, Wistar; D000077325:Ringer's Lactate; D013203:Staphylococcal Infections / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013212:Staphylococcus epidermidis / Q000187:drug effects*; D013530:Surgical Wound Infection / Q000473:pathology / Q000517:prevention & control*
D000900:Anti-Bacterial Agents; D007552:Isotonic Solutions; D000077325:Ringer's Lactate; D001414:Bacitracin; D007455:Iodine