# MDRO Management > MDRO management for MBBS Microbiology: MDR XDR definitions, MRSA VRE CRE precautions, drug-resistant TB regimens and stewardship. - Canonical URL: https://prepelephant.com/topics/mbbs/microbiology/mdro-management-micro - Exam / course: MBBS · Subject: Microbiology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "MDRO Management", PrepElephant, https://prepelephant.com/topics/mbbs/microbiology/mdro-management-micro ## Direct answer MDRO — the multidrug-resistant organism — is as much a ward-level problem as a laboratory label, and managing it means running infection control and antibiotic stewardship in parallel. The working definitions: MDR is acquired resistance to at least one agent in three or more antimicrobial classes; XDR is MDR plus susceptibility remaining to only one or two classes; pandrug-resistant means no tested agent works. The roster Indian hospitals actually face includes MRSA, vancomycin-resistant Enterococcus, ESBL and carbapenemase-producing Enterobacteriaceae, carbapenem-resistant Acinetobacter baumannii and Pseudomonas, Candida auris colonising ICU surfaces, and within the national TB programme the MDR, pre-XDR and XDR tuberculosis categories. Every one of these is managed with the same bundle: screen or surveil, isolate or cohort, enforce hand hygiene, clean the environment, remove devices early, and prescribe the narrowest effective therapy with scheduled review. ## What you must remember - **Definitions to quote:** MDR — non-susceptibility to at least one agent in three or more classes; XDR — MDR with remaining susceptibility to at most two classes; PDR — none; these standard definitions sit beside ICMR surveillance categories that Indian laboratories report. - **The priority organisms:** MRSA (mecA/PBP2a, cefoxitin screen), VRE (vanA in Enterococcus faecium), ESBL and carbapenem-resistant Enterobacteriaceae (NDM, KPC, OXA-48), carbapenem-resistant Acinetobacter baumannii — the signature Indian ICU pathogen — and Candida auris, first described in 2009 and now persistent on Indian hospital surfaces. - **Tuberculosis grading:** MDR-TB is resistance to isoniazid and rifampicin; pre-XDR adds any fluoroquinolone resistance; XDR-TB, per current WHO definitions, adds resistance to bedaquiline or linezolid — the NTEP basis for regimen choice and for molecular DR testing. - **Isolation practice:** contact precautions with gloves and gown, single room or cohorting of same-organism patients, dedicated equipment, and terminal cleaning after discharge — with chlorhexidine bathing and mupirocin decolonisation used selectively for MRSA carriers undergoing surgery. - **Hand hygiene:** the WHO five moments, alcohol rub as default unless spores (C. difficile) or norovirus demand soap and water — the single highest-yield intervention in every exam answer. - **Device stewardship:** review central lines, urinary catheters and endotracheal tubes daily with removal criteria, because biofilms convert brief colonisation into sustained bacteraemia. - **Stewardship pair:** empiric therapy de-escalated on culture reports, with an antibiotic policy and prescription audit; hospital infection control committees make these enforceable, and NABH accreditation checks the paperwork. ## The first 48 hours after one CRE admission A blood culture flags carbapenem-resistant Klebsiella on a surgical ward. The first hour is communication and placement: the patient moves to a single room or joins a CRE cohort, contact-precaution signage goes up, and dedicated stethoscope and thermometer arrive. Screening follows — groin and rectal swabs of roommates, because colonisation precedes infection and tells you whether this is importation or an established ward reservoir. The environment gets its share: daily chlorine-based cleaning of high-touch surfaces, and after discharge a terminal clean, with hydrogen peroxide vapour where available, since Acinetobacter and Candida auris survive dry surfaces for weeks. On the therapy side, the team re-justifies every line and catheter, confirms the isolate's carbapenemase mechanism if the laboratory can, and locks in a defined treatment endpoint. Finally, the discharge letter travels the organism forward — transfer calls to the receiving ward, so precautions restart on arrival instead of after the next positive culture. Across the hospital, the same admission feeds the AMR surveillance register: one more denominator in the ICMR data that eventually redirects the empiric antibiotic policy for everyone else. ## Where the exam sets traps The commonest scenario mistake is treating colonisation. A Candida auris isolate from a surveillance swab, or a carbapenem-resistant Klebsiella from a catheter specimen in a patient without fever or pyuria, needs precautions and device removal — not antifungals or colistin. Distinguish colonisation from infection explicitly in every answer. Second trap: the definitions drift — writing "MDR means resistant to three drugs" loses the mark; it is three or more classes, not agents. Third, students prescribe vancomycin for VRE or linezolid reflexively; the exam wants the susceptibility-guided choice (daptomycin or linezolid per source and susceptibility) plus the recognition that VRE mostly infects the already-hospitalised. For tuberculosis, quote the current ladder correctly — MDR, then pre-XDR with fluoroquinolone resistance, then XDR with additional bedaquiline or linezolid resistance — because older definitions (which required injectable resistance) still circulate in outdated guides and are deliberately used as distractors. ## Frequently asked questions ### What defines an organism as XDR rather than MDR? XDR isolates remain susceptible to only one or two antimicrobial classes, whereas MDR denotes non-susceptibility to at least one agent in three or more classes. ### Which precautions apply to a patient colonised with CRE? Contact precautions — gown and gloves, single room or cohorting, dedicated equipment, hand hygiene at WHO's five moments — plus screening of contacts and terminal environmental cleaning. ### How is XDR tuberculosis defined under current WHO criteria? Tuberculosis resistant to isoniazid and rifampicin, plus any fluoroquinolone, plus bedaquiline or linezolid — the NTEP category determining longer individualised regimens. ### Why is Candida auris an infection-control emergency? It colonises skin persistently, survives on dry surfaces for weeks, withstands common disinfectants and resists multiple antifungals, producing sustained ICU outbreaks. ### What is antimicrobial de-escalation in practice? Narrowing or stopping empiric broad-spectrum therapy once culture and susceptibility results return, paired with daily review of indications, doses and durations to limit resistance selection.