Bacteria now producing spores

[Guest guest]

INDEPTH: HOSPITAL INFECTIONS

Clostridium difficile FAQs

CBC News Online | March 21, 2005

It seemed to come out of nowhere a virulent strain of bacteria called

Clostridium difficile. It picked up that name because when it was

first discovered, it was difficult to grow in the lab.

C. difficile is not an uncommon bacterium but it had some infectious

disease specialists worrying that it has become the most dangerous

superbug to hit North American hospitals in a decade. In October 2004,

researchers found that 7,000 people had been infected with C.

difficile in Montreal since 2003, and at least 600 of them died.

Hospitals in Ottawa and Calgary have also experienced periodic outbreaks.

C. difficile is a very interesting organism, because it produces

spores, which can remain viable for months. There's a famous study

done by the University of Michigan, by Bob Fekety and his colleagues.

Essentially, they had a room of a patient with C. difficile. The room

was in an area of the hospital that was being renovated, so they

sealed the room for six months, then came back six months later and

were able to recover the organism from that room.

It lived there so well because of the spores, which are structures

that microorganisms make that allow them to survive in very hostile

environments. Not all microorganisms produce spores, but Clostridium

do. They're soil organisms; that's probably where they first came

from. In soil, there's tremendous competition among the microorganisms

for nutrients, so if there aren't sufficient nutrients, there are

certain signals sent to the organism saying, `There's not enough stuff

to eat; we need to go into our survival mode,' which is making spores.

When the environment is favorable again, these spores germinate and

become viable bacteria again. It's not hibernation, because there is

no metabolic activity; spores are metabolically inert. They're

protected from drying and heat and from many disinfectants, so that's

what makes them so problematic, Gilligan adds.

These spores can remain viable on any variety of surfaces that someone

who has this disease touches, especially if they haven't done a good

job of washing their hands. Spores are resistant to alcohol, so if

you're trying to control infection with C. difficile, it's important

that when caregivers come in contact with people with this disease,

they wash their hands with old-fashioned soap and water, he says.

Studies show that C. difficile is mainly found in the bathroom, but it

can be found on bedrails, on bedside tables, on the telephone, states

Gilligan. It's an organism that we have a lot of respect for, because

it can cause very severe diarrheal disease, and actually can cause

pseudomembranous colitis, which can result in the death of patients.

One of the things that we've seen recently is there are

`super-strains' that seem to cause more severe disease and have higher

mortality associated with them.

C. difficile can be found in the GI tracts of some patients, but it is

likely they carry it in spore form. When a patient is given

antibiotics, which disturbs the normal gut flora, the positive

organisms that typically keep C. difficile in check may be killed off,

allowing the spores to vegetate and produce toxin.

Gilligan observes that the main bugs that concern him are the

aforementioned water bugs, mainly because they're often resistant to

many different antibiotics. VRE is found in hospital environment in

the same types of places you find C. difficile. It's not going to

survive for months at a time, but if people with this organism in

their GI tract don't wash their hands, or if their bedpans are not

cleaned up as carefully as might be, the organism can remain viable in

the environment for some period of time.

A hallway setting, in contrast to patient rooms, may be host to fungi

rather than bacteria. Many hospitals no longer allow windows to be

opened for fear of mold spores entering the environment.

Moreover, patients with compromised immune systems should not receive

flowers or plants, because Pseudomonas which can affect them is found

all over the surface of flowers and in the water. If you send them

plants, it's in the soil, so people who are immuno-suppressed should

only be sent artificial flowers without water. Also, people who are

immuno-suppressed can't have salads, because salads have Pseudomonas

on their surface. It's very difficult to get soil off the lettuce in

such a way that the microorganisms in the soil are eliminated, so raw

vegetables, especially lettuce, are problematic, Gilligan emphasizes.

Our immune systems are miracles, he says. Microorganisms are

everywhere. We walk through a soup of microorganisms every day. We are

exposed to microorganisms that in the hospital kill people, and we are

exposed to them every day with no ill effect.