Tularemia and once-daily gentamicin

Abstract

Tularemia and Once-Daily GentamicinTularemia has been a subject of interest over the last few years, as it can be used as a biological weapon (2).An aminoglycoside such as streptomycin has been the accepted treatment of choice and can achieve a 100% cure rate.Gentamicin administered three times a day has been used as an alternative (5).The use of once-daily dosing has been recommended, but few data regarding its success rate against this infection are available.We report two cases of glandular tularemia successfully treated with once-daily gentamicin.Case 1.A 23-year-old white male sustained a bite on his index finger while petting a kitten.Within 5 days, he developed fever, painful axillary lymph nodes, myalgia, and headache.He was treated with ceftriaxone for 2 days and then with amoxicillin-clavulanate for 14 days with some improvement.However, symptoms recurred after he finished the antibiotic course.He was referred for further workup and management.A tularemia agglutination test result was 1:320.He was started on intravenous (i.v.) gentamicin at 5 mg/kg of body weight daily as outpatient therapy, which was adjusted to maintain a trough serum concentration of 0.5 to 1.5 g/ml and a peak serum concentration of 8 to 10 g/ml.His serum creatinine level before the initiation of therapy was 0.8 mg/dl.His condition improved significantly within 48 h.On day 7 of treatment, he underwent incision and drainage of an axillary lymph node, as it was large and fluctuant.The culture was sterile.The patient finished 10 days of treatment.His serum creatinine level at the end of therapy was 0.8 mg/dl.Case 2. A 28-year-old male, a brother of the first patient, was bitten by the same kitten and within three days developed generalized muscle aches and painful axillary lymph nodes.He was treated with ceftriaxone for 1 day followed by azithromycin for 5 days, with improvement.His symptoms recurred after the cessation of therapy.He was subsequently treated with ceftriaxone for 2 days and then with amoxicillin-clavulanate for 10 days, with some improvement.Upon referral, a tularemia agglutination test result was 1:160.The serum creatinine level was 0.7 mg/dl.He was treated with i.v.gentamicin 5 mg/kg daily for 7 days to keep peak and trough serum concentrations in the same range as for the first patient, with complete resolution of symptoms.The posttherapy serum creatinine level was 0.8 mg/ dl.Neither patient experienced side effects or relapse after 5 months.Discussion.Francisella tularensis is a gram-negative pathogen primarily of animals and occasionally of humans.Tulare-

Part of CIRS Nexus · Curated by Lauren Lowenstein, The Biotoxin Lady