The brush problem

Date: 12.10.26
Company: Nanosonics
Reception score: 23 of 30

A technician still cleans the inside of every endoscope with a brush pushed by hand. Nanosonics has built CORIS to do that step by machine, and its first machine, trophon, shows how long a change like this takes and what it waits for.

A Lens specimen render in cypress and lime

Reception score	23 of 30 CORIS on its own scores 19 of 30
Cash	A$155.2m, no debt
Our prediction	CORIS will be in use at 20 to 30 customer sites by June 2027 Checked at the full-year result, August 2027

A colonoscope used at nine in the morning has often been inside another patient at eight. Between the two procedures a technician pushes a small brush by hand through the scope's internal channels, each a few millimetres wide and about as long as a person is tall, and repeats the job dozens of times a day in a sterilising department that is often short of staff. Nanosonics, the Sydney company that has built a machine to take over the job, calls it "the one step in endoscope reprocessing that has remained manual, variable and unverified".

What Nanosonics does

Hospitals reuse ultrasound probes and endoscopes on patient after patient, and each one has to be cleaned properly in between. Nanosonics sells machines that do that cleaning the same way every time and keep a record of it.

The first of those machines was trophon, which disinfects the ultrasound probes used for internal scans in a closed chamber with a hydrogen peroxide mist, in hospitals where staff once soaked or wiped each probe by hand. Nanosonics now has 39,230 trophon units installed around the world, and each cycle uses a Nanosonics cartridge, so every installed machine keeps earning after the sale in the way a printer earns through its ink. Recurring revenue made up A$149.2m of the A$203.9m Nanosonics took in during the last financial year.

The second machine, CORIS, does the brushing inside an endoscope by machine, at about 10 cleaning cycles a day for each device (company estimate).

Why the brush matters

The brushing decides whether the rest of the cleaning works, because a disinfecting machine handles the scope afterwards and disinfectant cannot reach through residue the brush left behind. Between 2012 and 2015 duodenoscopes, the scopes used to reach the bile ducts through the gut, were linked to at least 25 outbreaks of drug-resistant infection and at least 250 infected patients worldwide. The duodenoscope design carried part of the blame, and the outbreaks also showed how hard these instruments are to clean.

A hand brush depends on the person holding it and on the time that person has before the next scope arrives, while a machine cleans every channel the same way each time and records that it has done so.

What has to change

Nanosonics has seen this change once before, because trophon took roughly a decade to become the norm for ultrasound probes and guidelines pushed hospitals towards it. A guideline gives a hospital a reason to create a budget line, and a budget line turns a sensible machine into a routine purchase.

CORIS is at the start of the same road, and the US Food and Drug Administration authorised it in 2025 for a single Olympus colonoscope. Each scope model has its own channel layout, so each model needs separate testing and clearance, and the FDA cleared a first batch of additional models in March 2026. CORIS is now in controlled release with its first hospital customers, and Nanosonics plans a wider launch through the 2027 financial year. The company's filings describe no new checking work for staff, and the first customer sites will show whether any appears.

The people who do the brushing want the machine, and the people who pay for it have not yet been given a reason to buy it. Each CORIS cycle costs 4 to 6 times a trophon cycle (company estimate), no insurer pays for it, and hospitals have no budget line for it. The pressures that could create one are building, as hygiene standards for scopes tighten, sterilising departments struggle to hire and keep technicians, and disposable scopes cost a great deal per procedure while adding to plastic waste, and a guideline or standard that expects automated cleaning would turn those pressures into a budget.

Nanosonics can afford to wait for that guideline, because trophon earned about A$50.6m in operating profit last financial year and pays for the CORIS launch, and the company holds A$155.2m in cash with no debt. Management expects operating costs to rise 10% to 15% this financial year, so the costs of the launch arrive before CORIS sales do.

We give Nanosonics a reception score of 23 out of 30 and give CORIS on its own 19 out of 30.

What could slow it

No standard requires automated cleaning yet, and the main US standard asks hospitals to verify that cleaning worked.
The evidence so far is a laboratory study, with no published study of patient infection rates.
Approval comes one scope model at a time, and a hospital will hold off buying a machine that cleans only some of its scopes, so CORIS needs the best-selling models from Olympus, Pentax and Fujifilm cleared before it becomes an easy purchase.
Disposable scopes have caught on for some lung procedures, though they still cost far more than reusable scopes for most other work.
Olympus makes most of the world's endoscopes and could build a competing system.
trophon pays for CORIS, so trophon has to keep growing against hand soaks and wipes (Tristel, CS Medical) and UV devices (Germitec) in a probe disinfection market worth about US$555m in 2023, of which we estimate Nanosonics holds roughly a quarter. A hospital that has built its routines around trophon cartridges has good reason to stay, and a hospital without trophon has less reason to start.
If CORIS stalls and Nanosonics keeps spending on it, trophon carries the cost for longer.

What to watch

We predict CORIS will be in use at 20 to 30 customer sites by June 2027, and the full-year result in August 2027 will show whether it is.
The number of scope models the FDA clears matters, and so does whether they include the models hospitals use most.
Published data on technician time saved would strengthen the case, and a study of infection rates would strengthen it further.
A professional body recommending automated cleaning would be the strongest single signal.
North American trophon upgrades reached a record last year, up 32%, and trophon's growth is what pays for the wait.

What would change our view

We would lower the score if CORIS falls well short of 20 to 30 sites while trophon growth stalls, or if Olympus launches its own system. We would raise the CORIS score if a professional body or standard came to expect automated cleaning.