C. difficile Resisted Disinfection in Hospital Outbreak

Clostridium difficile

Even years after hospital workers believed they had disinfected all contaminated surfaces following an outbreak of (C. difficile) the organisms were found, Costa Rican researchers reported.

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In a study published in The American Journal of Infection Control, a research team reported that contamination that surged during the outbreak and persisted in lesser concentration two years later.

In an article called “Molecular detection of Clostridium difficile on inert surfaces from a Costa Rican hospital during and after an outbreak” Luisa Morales and colleagues analyzed the relative frequency inert hospital surfaces tested positive for the nonaerobic bacillus while the hospital was in the midst of an infection outbreak and again two years after it had passed. The researchers are from the Centro de Investigación en Enfermedades Tropicales and Facultad de Microbiología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, SJ, Costa Rica.

All 75 environmental samples collected from bed rails, walls, and exam tables in general medical and surgical wards were tested for the bacteria.

Using molecular sequencing DNA analysis the team identified C. difficile on 40% of the sampled surfaces. In the outbreak 71% outbreak samples had tested positive. Overall the number of samples showing C. difficile was nearly 2.5 times higher during the outbreak. This 2.5× ratio was maintained when the comparison was restricted to the wards that were sampled both during and after the outbreak (72% vs 35%, P = .016).

While C. difficile was detected in only 28% of post-outbreak samples researchers recognized some of the very organisms present during the outbreak two years earlier.

The study illustrates the fact that C. difficile, which the Centers for Disease Control (CDC) cites in 15% to 25% of antibiotic-associated diarrhea cases, can shield itself from harsh environments with a protective outer spore.

Researchers noted that some of the sample locations chosen were off the beaten path for cleaning staff, and the detection rate of the bacteria in wards where patients were not experiencing diarrhea points to intra-hospital transmission.

They concluded that “Our results show that environmental surfaces in the hospital analyzed are continuously being contaminated with C. difficile DNA and that their level of contamination is higher during an outbreak than after it.”

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