Rapid Development of Acinetobacter baumannii Resistance to Tigecycline

• Published in: Pharmacotherapy 2007-08, Vol.27 (8), p.1198-1201
• Main Authors: Reid, Gail E., Grim, Shellee A., Aldeza, Christine A., Janda, William M., Clark, Nina M.
• Format: Article
• Language: English
• Subjects: Acinetobacter baumannii; Acinetobacter baumannii - drug effects; Acinetobacter Infections - drug therapy; Anti-Bacterial Agents - pharmacology; Biological and medical sciences; Drug Resistance, Bacterial; Female; Humans; Kidney Transplantation; Liver Transplantation; Medical sciences; Microbial Sensitivity Tests; Middle Aged; Minocycline - analogs & derivatives; Minocycline - pharmacology; Osteomyelitis - drug therapy; Osteomyelitis - microbiology; Pharmacology. Drug treatments; Pneumonia, Bacterial - drug therapy; Pneumonia, Bacterial - microbiology; resistance; Spinal Diseases - drug therapy; Spinal Diseases - microbiology; Tetracycline Resistance; tigecycline; Urinary Tract Infections - drug therapy; Urinary Tract Infections - microbiology
• ISSN: 0277-0008; 1875-9114
• DOI: 10.1592/phco.27.8.1198

A 53‐year‐old woman experienced a multidrug‐resistant (MDR) Acinetobacter baumannii urinary tract infection 5 months after undergoing kidney and liver transplantation. The tigecycline minimum inhibitory concentration (MIC) for her A. baumannii isolate was 1.5 μg/ml; the patient received 2 weeks of therapy with intravenous tigecycline as a 100‐mg loading dose followed by 50 mg every 12 hours, with no lapses in treatment and with resolution of the infection. Three weeks later, MDR A. baumannii was isolated from her sputum in the setting of clinical evidence of pneumonia, and tigecycline was restarted; the tigecycline MIC for the A. baumannii isolate was 2 μg/ml. At approximately the same time, the patient was found to have a paraspinal abscess and spinal osteomyelitis. Cultures of the abscess fluid grew A. baumannii with a tigecycline MIC of 24 μg/ml. A follow‐up sputum culture again yielded A. baumannii, but with a tigecycline MIC of 24 μg/ml. Urine culture at that time also grew A. baumannii with a tigecycline MIC of 24 μg/ml. Clinicians should be aware that tigecycline MICs for A. baumannii isolates may increase during therapy with tigecycline after only brief exposure to the drug. Patients receiving tigecycline for Acinetobacter should be monitored for the development of clinical resistance, and isolates should be monitored for evidence of microbiologic resistance.