ABSTRACT
We report a relapsed case of a 25 year-old man with multi-drug resistant Salmonella serovar Typhi (MDRST) bacteremia who had recently returned from travel in India. Due to unresponsiveness to ciprofloxacin and ceftriaxone, we examined the strain's resistance to quinolones and extended-spectrum beta-lactamases (ESBLs). The strain had a single gyrA mutation at codon 83 (Ser83Phe), which explains its decreased susceptibility to fluoroquinolone and resistance to nalidixic acid. In the screening tests of ESBLs, TEM-1 was positive, which is beta-lactamase but not ESBL. The patient was finally successfully treated with meropenem and aztreonam. In the presence of clinical unresponsiveness despite favorable sensitivity tests, further laboratory evaluations are needed, which should include studies of genes related to antibiotic resistance and ESBLs. In addition, further prospective trials should be done about the possible inclusion of antibiotics not yet mentioned in the current guidelines. With MDRST on the rise worldwide, the most optimal and effective line of antibiotic defense needs to be devised.
Subject(s)
Adult , Humans , Male , Anti-Bacterial Agents/administration & dosage , Aztreonam/administration & dosage , Bacteremia/drug therapy , Drug Resistance, Bacterial/genetics , Drug Resistance, Multiple/genetics , Drug Therapy, Combination , Salmonella typhi/drug effects , Thienamycins/administration & dosage , Typhoid Fever/drug therapyABSTRACT
Aztreonam belongs to the monobactam group of naturally occurring antibiotic compounds characterized by a monocycling ring structure. Aztreonam is the first monobactam that has been approved for use in pediatric medicine by US FDA in the year 1998.