Two lab workers in three months hospitalised with ‘rare’ typhoid infections caught at work

In just three months, two lab workers – in different labs and different cities – were hospitalised with typhoid caught from samples they handled.

Experts have told The Post lab-related infections should be very rare, raising the question of whether the incidents point to broader safety issues in diagnostic laboratories, which scientists say are under “extraordinary pressure”.

Typhoid fever is a potentially fatal bacterial disease. In 2022, there were 46 cases nationwide.

Caused by the Salmonella typhi bacteria, typhoid is normally spread by food or water contaminated with infected faeces. Most cases picked up in New Zealand originate overseas.

The first typhoid lab infection happened in Auckland in March, at a lab owned by private nationwide provider, Awanui Group. Group quality and safety manager, Saad Mansour, said workplace infections were “incredibly rare” and this was the company’s only case in the past five years.

An investigation concluded the infection was caused by “an isolated case of an employee failing to follow PPE [personal protective equipment] procedures”, Mansour said. While the lab had “robust procedures” to prevent infections, the incident had prompted increased monitoring and education.

The lab worker has fully recovered and returned to work.

The second infection was at Canterbury Health Laboratories, in May. A lab technician suffered intestinal bleeding after being infected with typhoid from a sample she handled in April.

A review into that case could not pinpoint the infection’s source. However, it found that handling concentrated suspensions of bacteria outside of a biosafety cabinet was a contributing factor.

The fact staff were not vaccinated against Salmonella typhi also contributed.

The review also noted that the gloves used did not properly cover lab coat cuffs, hand hygiene was not routinely audited, alcohol-based sanitiser was only available outside the lab, and recommendations following a 2019 lab-related infection – from the shigella bacteria – had not been fully implemented.

The review made 17 recommendations, including offering staff free vaccinations against Salmonella typhi, reviewing safety practices, introducing hand hygiene audits, banning phone use and sourcing longer gloves.

Te Whatu Ora’s interim Canterbury general manager of pathology and laboratories, Gloria Crossley, said they took health and safety very seriously, and multiple procedures were already in place to stop staff getting infected from samples they handled.

However, the lab had now ditched one riskier test involving high concentrations of bacteria, and the remaining review recommendations were being implemented.

“Our staff member is recovering, and we continue to support them during this time. We believe the changes we have made will further reduce the risk of this type of incident happening again.”

While lab-related infections have to be reported to WorkSafe, Stuff could not find any national statistics documenting how often they happen. WorkSafe could not extract its data in time.

ACC found seven workplace claims from 2000-2023 that possibly involved lab-caught infections.

The two typhoid cases were the only known lab-related infections in publicly-run labs in the past 12 months.

Institute of Medical Laboratory Science president Terry Taylor said labs were struggling with short staffing and a workload “going through the roof”.

However, he did not believe that was causing a lapse in infection prevention standards.

“We are certainly not in a situation where we would ever compromise our practitioner safety…Our labs are under extraordinary pressure at the moment, but I don’t think this is related at all.

“It just highlights what the risks are with working in a diagnostic laboratory these days. Our labs are basically the most controlled environments in the medical field, but occasionally things do slip through.”