2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Supplementary Classification Of Factors Influencing Health Status And Contact With Health Services V01-V85 > Persons With Potential Health Hazards Related To Communicable Diseases V01-V09 > Infection With Drug-Resistant Microorganisms V09.* > 2006 ICD-9-CM Diagnosis V09.91 Infection with drug-resistant microorganisms unspecified with multiple drug resistance View the most recent version of ICD-9-CM V09.91 Adaptation of tumor cells to anticancer drugs in ways that make the drugs less effective. Simultaneous resistance to a spectrum of unrelated drugs following exposure to a single agent. It may result from overexpression of the integral plasma membrane protein, P-glycoprotein. This adaptation of tumor cells to anticancer drugs, mediated by inactivation of the drug or removing it from the target tumor cells, tends to make the drugs less effective. Simultaneous resistance to several structurally and functionally distinct drugs. V09.91 is a specific code that can be used to specify a diagnosis V09.91 contains 2 index entries View the ICD-9-CM Volume 1 V09.* hierarchy Alternate Terminology Multiple drug resistance NOS  Index entries containing V09.91: Resistance, resistant (to) drugs by microorganisms V09.90 MDRO (multiple drug resistant organisms ) NOS V09.91 multiple drug resistant organisms NOS V09.91