Evaluation of biochemical and molecular techniques in the diagnosis of urinary isolates of Enterobacter cloacae

Enterobacter spp. belongs to the family of Enterobacteriaceae and has a variety of phenotypic and genotypic profiles. Within Enterobacter cloacae complex, six genetically related and phenotypically similar species have been merged and strains belonging to these species are encountered among the most common strains able to cause severe opportunistic infections in hospitalized patients. Sequence analyzing a segment of hsp60 gene belong to this complex have demonstrated 13other genetic clusters. Since this complex is rarely identified in Iran, therefore, we aimed to evaluate the efficiency of phenotypic (commercial routine kit) and molecular methods for detecting this complex in urinary isolates. In this study 74 Enterobacter cloacae urinary isolates, collected from 6 large hospitals in Tehran, were characterized by API20E kit and for final approval of diagnosis, hsp60 gene sequencing was performed. Using API20E kit for detecting Enterobacter cloacae in comparison to hsp60 sequencing, as gold standard for determining the species, sub-species and genotypes in Enterobacter cloacae complex, have demonstrated sensitivity and specialty about 88% and 60%, respectively in bacteria detection. Considering the importance and particular role of Enterobacter cloacae complex in causing hospital-acquired and opportunist infections and according to limited capability of API20E kit in providing precise analytic data, performance of complimentary tests or molecular methods, such as hsp60 sequencing, with high accuracy and validity, are highly suggested.