The bla_TEM genes encode TEM-family β-lactamases (first identified as penicillinases); many TEM variants have mutations that extend their activity to third-generation cephalosporins (ESBLs). TEM-type ESBLs (e.g. TEM-3, TEM-10) confer resistance to cefotaxime, ceftazidime, etc. on plasmids or integrons. Detection of bla_TEM indicates a likely ESBL phenotype similar to bla_SHV, guiding clinicians to avoid cephalosporins and consider carbapenems or β-lactam/β-lactamase inhibitor combinations for therapy (Tzouvelekis et al. 2012, Liakopoulos et al. 2016).
Liakopoulos, A., Mevius, D., & Ceccarelli, D. (2016). A Review of SHV Extended-Spectrum β-Lactamases: Neglected Yet Ubiquitous. Frontiers in microbiology, 7, 1374. https://doi.org/10.3389/fmicb.2016.01374
Tzouvelekis, L. S., Markogiannakis, A., Psichogiou, M., Tassios, P. T., & Daikos, G. L. (2012). Carbapenemases in Klebsiella pneumoniae and other Enterobacteriaceae: an evolving crisis of global dimensions. Clinical Microbiology Reviews, 25(4), 682–707.
