title: Gallium maltolate as an alternative to macrolides for treatment of presumed Rhodococcus equi pneumonia in foals.
abstract: BACKGROUND
  Macrolide-resistant isolates of Rhodococcus equi are emerging, prompting the search for clinically effective alternative antimicrobials.
  
  
  OBJECTIVE
  The proportion of foals with ultrasonographic evidence of pneumonia presumed to be caused by R. equi that had a successful outcome when administered gallium maltolate (GaM) PO would not be more than 10% inferior (ie, lower) than that of foals receiving standard treatment.
  
  
  METHODS
  Fifty-four foals with subclinical pulmonary abscesses among 509 foals at 6 breeding farms in Kentucky.
  
  
  METHODS
  Controlled, randomized, prospective noninferiority study. Foals with ultrasonographic lesions >1 cm in diameter (n = 54) were randomly allocated to receive per os either clarithromycin combined with rifampin (CLR+R) or GaM, and followed up for 28 days by daily physical inspections and weekly (n = 1 farm) or biweekly (n = 4 farms) thoracic ultrasound examinations by individuals unaware of treatment-group assignments. Treatment success was defined as resolution of ultrasonographically identified pulmonary abscesses within 28 days of initiating treatment. Noninferiority was defined as a 90% confidence interval for the observed difference in CLR+R minus GaM that was ≤10%.
  
  
  RESULTS
  The proportion of GaM-treated foals that resolved (70%; 14/20) was similar to that of foals treated with CLR+R (74%; 25/34), but we failed to demonstrate noninferiority for GaM relative to CLR+R; however, GaM was noninferior to CLR+R treatment when results from a noncompliant farm were excluded.
  
  
  CONCLUSIONS
  Gallium maltolate is not inferior to macrolides for treating foals with subclinical pneumonia. Use of GaM might reduce pressure for macrolide-resistance in R. equi.
authors: Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX.
authors: Noah D
authors: ND
authors: Cohen
authors: McGee Medicine Center, Hagyard Equine Medical Institute, Lexington, KY.
authors: Nathan M
authors: NM
authors: Slovis
authors: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA.
authors: Steeve
authors: S
authors: Giguère
authors: McGee Medicine Center, Hagyard Equine Medical Institute, Lexington, KY.
authors: Samantha
authors: S
authors: Baker
authors: Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX.
authors: M Keith
authors: MK
authors: Chaffin
authors: Terrametrix, Menlo Park, CA.
authors: Lawrence R
authors: LR
authors: Bernstein
mesh_terms: D000193:Actinomycetales Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D006734:Horse Diseases / Q000188:drug therapy* / Q000382:microbiology; D006736:Horses; D009942:Organometallic Compounds / Q000627:therapeutic use*; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D011753:Pyrones / Q000627:therapeutic use*; D016929:Rhodococcus equi / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D009942:Organometallic Compounds; D011753:Pyrones; C512662:gallium maltolate
keywords: Antibiotic choices; Antimicrobial resistance; Antimicrobials; Equivalency