Antibiogram of environmental isolates of Acinetobacter calcoaceticus from Nkonkobe Municipality, South Africa

Abstract

The antibiogram of Acinetobacter isolates from freshwater and soil samples in Alice and Fort Beaufort towns in Nkonkobe Municipality, South Africa were assessed for their extended betalactamase (ESBL) spectrum. Eighty-six Acinetobacter isolates were obtained from the 50 samples of soil and 50 samples of water (25 in each location) analysed. The resistance of the Acinetobacter isolates ranged between 30-100% against penicillin G, ceftriazone, nitrofurantoin, erythromycin and augmentin, while 9% showed intermediate response to minocycline, and 10% were resistant to oxytetracycline. Both Tet B and Tet 39 were detected in 66.7 % of the tetracycline resistant Acinetobacter isolates and in 44.4 % of the intermediately tetracycline resistant Acinetobacter isolates. An observation of 9.3% phenotypic expression of ESBLs was made while 3.5% were carrying the blaCTX-M-1 gene; all of which were susceptible to the fluoroquinolone. The multiple antibiotic resistance (MAR) index of > 0.2 indicates that the isolates emerged from high-risk sources, in line with conventional standards. Commensal Acinetobacter spp in the environment have proven to be one of reservoirs for antibiotic resistance genes.