The bacteriostatic properties of ear tubes made of absorbable polylactic acid.
OBJECTIVE
Tympanostomy tube placement remains the most common reason children are brought to the operating room. Of the known complications, transient, recurrent, and chronic otorrhea represent the most common and challenging sequelae of tube insertion. This study was performed to determine if the acidic nature of the polymer of lactic acid (PLA), a possible material for the construction of ear tubes, would have bacteriostatic properties.


METHODS
Experimental PLA tubes and control fluoroplastic tubes were inoculated with a broth of Pseudomonas aeruginosa or Staphylococcus aureus and incubated. Fluid recovered from the tubes was plated and incubated again. Colony counts were recorded at 24 and 48 h. Two separate trials were conducted for each organism. Repeated measures analysis of variance (ANOVA) models were used to assess the effects of the type of tube, the experimental run, and the tube by run interaction on colony counts.


RESULTS
In the Pseudomonas experiments, the mean colony count of the PLA tube group (Run 1: 1.0; Run 2: 26.6) was significantly lower than the mean colony count in the fluoroplastic tube group (Run 1: 132.6; Run 2: 122.2; p=0.0150). Similarly, in the S. aureus experiments, the mean colony count of the PLA tube group (Run 1: 88.2; Run 2: 92.6) was significantly lower than the mean colony count in the fluoroplastic tube group (Run 1: 335.0; Run 2: 325.8; p<0.0001).


CONCLUSIONS
PLA has many properties including an apparent bacteriostatic quality, which may make it an attractive material for the construction of tympanostomy tubes.
Ludwick
James J
JJ
Bobby R. Alford Department of Otolaryngology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA.
Rossmann
Susan N
SN
Johnson
Marcella M
MM
Edmonds
Joseph L
JL
D020341:Absorbable Implants / Q000382:microbiology; D000890:Anti-Infective Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D002648:Child; D006801:Humans; D019344:Lactic Acid / Q000494:pharmacology* / Q000627:therapeutic use*; D008876:Middle Ear Ventilation; D010034:Otitis Media with Effusion / Q000382:microbiology*; D011091:Polyesters; D011108:Polymers / Q000494:pharmacology* / Q000627:therapeutic use*; D011552:Pseudomonas Infections / Q000517:prevention & control; D011550:Pseudomonas aeruginosa; D013203:Staphylococcal Infections / Q000517:prevention & control; D013211:Staphylococcus aureus
D000890:Anti-Infective Agents; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)