A pathogen acquires an extended-spectrum beta-lactamase (ESBL) gene via plasmid transfer in a hospital ward. Which immediate epidemiological patterns would you expect to observe, and why?

• A. A sudden global extinction of that bacterial species caused by plasmid acquisition, because plasmids always impose lethal metabolic costs that result in immediate extinction of host bacteria.
• B. An immediate drop in all infection rates across the hospital as the plasmid converts bacteria into harmless commensals, which eliminates the need for infection control measures.
• C. A switch from bacterial to viral transmission dynamics within 24 hours because ESBL genes convert bacterial genomes into viral genomes and change host range instantly.
• D. An increase in treatment failures for beta‑lactam antibiotics and potential clustering of resistant infections among patients with prior antibiotic exposure or indwelling devices, because plasmid-mediated ESBL confers enzymatic resistance that spreads clonally and horizontally.

Answer: (D)