The Threat of Antibiotic Resistance (image) Washington University in St. Louis Share Print E-Mail Caption A CDC microbiologist holds up a plate used to identify resistance in bacteria known as Enterobacteriaceae. Bacteria that are resistant to carbapenems, considered 'last resort' antibiotics, produce a distinctive clover-leaf shape on the plate. Credit Centers for Disease Control Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.