Use of Ceftazidime Resistance Pattern as a Potential Biological Marker to Predict the Presence of the bla _(TEM-1) Gene in Clinical Isolates of the Acinetobacter calcoaceticus-baumannii Complex

The Acinetobacter calcoaceticus-baumannii complex (ABC) is considered a major infectious pathogen in Taiwan. The aim of this study was to investigate whether the ceftazidime (CAZ) resistance pattern can be used as a biological marker to predict the presence of the bla _(TEM-1) gene in clinical ABC isolates. A cross-sectional, prospective study was conducted at a hospital between April 1, 2008 and March 31, 2009. A total of 413 clinical ABC isolates were collected. The bla _(TEM-1) gene was detected using polymerase chain reactions. We divided the 413 clinical isolates into three clusters and 32 subgroups by the finite mixture method based on the antibiotics resistance patterns. In our study, 31.2% (10/32) of the ABCs carried the bla _(TEM-1) gene and 100% (10/10) of the bla _(TEM-1)-positive isolates were CAZ-resistant (p = 0.001). The performance of the CAZ phenotype in terms of predicting the presence of the bla _(TEM-1) gene was as follows: sensitivity = 90.9%, specificity = 61.9%, false positive = 9.1%, false negative = 38.1%, positive predictive value = 55.6%, and negative predictive value = 92.9%. We concluded that the CAZ resistance phenotype could be a potential biomarker for the bla _(TEM-1) gene in ABC. Further experiments are necessary to confirm this finding.