Let’s say hypothetically one day you come across this Gram stained slide of a positive blood culture from a patient on the haematology unit.
Yup, it is a mould. Those are hyphae. We don’t often see moulds in blood cultures but there is one that typically infects haematology patients. Fusarium spp. OK, these are immunocompromised patients who are more susceptible to fungal infections, fungi are everywhere, especially in the tropics, bad things happen.
Over the next 3 weeks you get another 2 cases of Fusarium fungaemia. All 3 patients are on the same unit. You check that they were not admitted with the infection-they weren’t. Now this is a bit more disconcerting. Intuitively you know that this is more than what you would expect. However to be sure you extract data for all Fusarium spp. isolated from blood cultures in the last 8 years as recorded in the Laboratory Information System. Up to the previous month there have been only 3 additional cases, and none in the last 3 years.
Time to contact the infection control team. What is the likely source? Fusarium spp. are readily found in the environment (has there been any renovation work performed around the ward? Was there a contaminated product in common use?), but are particularly a pathogen of plants (has someone been bringing cut flowers into the unit?-surely not). But we also know from experience that Fusarium spp. are also readily found in the wet environment. A large outbreak of F. solani complex keratitis in 2005-2006 was thought to be due to contact lens solution bottles being contaminated in the patient’s home bathroom environment.
In the meantime you do a Pubmed search for outbreaks of Fusarium spp.
There aren’t many!
In Greece, a Fusarium verticillioides outbreak among immuncompetent patients was associated with reconstruction works. Environmental samples were negative, though water sources were not very thoroughly investigated. (Georgiadou SP, 2014).
There have been a number of small defined outbreaks described in Brazilian haem-oncology units. One (Litvinov N, 2015) found invasive F. soloni and F. oxysporon associated with positive cultures in the taps, showers, drains and room air, whereas another (Carlesse F et al, 2017) could find no environmental source.
A much earlier study from a Texas Medical Center (Anaissie EJ, 2001) had in fact already investigated the risk posed by the hospital water distribution system, though this was not in the context of a defined outbreak. They noticed that there were molecular matches between patient and environmental isolates, and concluded that the water distribution system of a hospital could be a reservoir for Fusarium spp. (and other pathogens).
Fusarium species was recovered from 57% of water system samples. 88% of sink drains grew F. solani; 16% of sink faucet aerators and 8% of shower heads yielded F. oxysporum. F. solani was isolated from the hospital water tank. Aerosolization of Fusarium species was documented after running the showers.
On the basis of their findings, the authors recommended that hospitals with cases of fusariosis (not of community-onset) should consider testing their water supply for the presence of opportunistic moulds. If such fungi were recovered from the water system, policies to avoid or minimize exposure of immunosuppressed patients to tap water from any source should be implemented (e.g. by providing boiled water for drinking). In addition, patients should avoid showering during severe immunosuppression because of the risk of acquiring the organisms through aerosolization of contaminated water. They recommend that bed baths with sterile disposable sponges be performed instead.
So is it in fact possible to isolate Fusarium spp from a shower head?
Can’t actually detach the shower head plate in this case, so sampling can only be performed where the head is detached from the hose at the handle.
Looks fairly clean as you would expect. Just water, no gunk or visible biofilm.
Acknowledgment: Thanks to the Department of Infection Prevention and Control, SGH for assistance with the shower photos.
Georgiadou SP, Velegraki A, Arabatzis M, Neonakis I, Chatzipanagiotou S,Dalekos GN, Petinaki E. Cluster of Fusarium verticillioides bloodstreaminfections among immunocompetent patients in an internal medicine department after reconstruction works in Larissa, Central Greece. J Hosp Infect. 2014 Apr;86(4):267-71. doi: 10.1016/j.jhin.2014.01.011. Epub 2014 Feb 27. PubMed PMID: 24650721. (no free access)
Litvinov N, da Silva MT, van der Heijden IM, Graça MG, Marques de Oliveira L, Fu L, Giudice M, Zilda de Aquino M, Odone-Filho V, Marques HH, Costa SF, Levin AS. An outbreak of invasive fusariosis in a children’s cancer hospital. Clin
Microbiol Infect. 2015 Mar;21(3):268.e1-7. doi: 10.1016/j.cmi.2014.09.004. Epub 2014 Oct 12. PubMed PMID: 25658562. (free access)
Carlesse F, Amaral AC, Gonçalves SS, Xafranski H, Lee MM, Zecchin V, Petrilli AS, Al-Hatmi AM, Hagen F, Meis JF, Colombo AL. Outbreak of Fusarium oxysporum infections in children with cancer: an experience with 7 episodes of
catheter-related fungemia. Antimicrob Resist Infect Control. 2017 Sep 7;6:93.
doi: 10.1186/s13756-017-0247-3. eCollection 2017. PubMed PMID: 28912948; PubMed Central PMCID: PMC5588724. (free access)
Anaissie EJ, Kuchar RT, Rex JH, Francesconi A, Kasai M, Müller FM, Lozano-Chiu M, Summerbell RC, Dignani MC, Chanock SJ, Walsh TJ. Fusariosis associated with pathogenic fusarium species colonization of a hospital water system: a new paradigm for the epidemiology of opportunistic mold infections. Clin Infect Dis. 2001 Dec 1;33(11):1871-8. Epub 2001 Oct 24. PubMed PMID: 11692299. (free access)