Keyboard Contamination in Intensive Care Unit: Is Cleaning Enough? Prospective Research of In Situ Effectiveness of a Tea Tree Oil (KTEO) Film

After the SARS-CoV-2 pandemic, disinfection practices and microbial load reduction have become even more important and rigorous. To determine the contamination of keyboard surface and the relative risk to transfer healthcare-associated pathogens to susceptible patients, as it frequently happens in Intensive Care Unit (ICU), a standard keyboard (SK), a cleanable keyless keyboard (KK) with smooth surface and a standard keyboard coated with a 3M Tegaderm film added with active essential oil (tea tree oil) (KTEO) were tested. S. aureus, including MRSA strains, were detected in ICU, with values ranging from 15% to 57%. Gram negative strains belonging to the Enterobacteriaceae family were also found with values ranging from 14% to 71%. Similar Gram positive and Gram negative strains were found on all surfaces, but with low percentage, and only environmental bacteria were detected using the settling plates method. The Microbial Challenge Test performed on KTEO showed high rates of decrease for all the pathogens with statistical significance both at 24 and 48h (p=0.003* and p=0.040*, respectively). Our results suggest that the use of KTEO may be a feasible strategy for reducing the transmission of pathogens in health care setting and may be complementary to surface cleaning protocols

The effect of Clostridium Difficile toxins A and B on ligated rabbit ileal loop and cultured cell line BK

Abstract: Clostridium difficile has been recognized as the major cause of pseudomembranous colitis. This bacterium produces two toxins (An enterotoxin-cytotoxin and a potent cytotoxin called toxin A and toxin B respectively). These toxins have implicated in pathogenesis of the disease. However, histopathological effects of their molecular mass less than 100KDa have been essayed. In the present study, we examined the dose response and time course of these toxins in ligated rabbit ileal loop and cell culture line BK (Bovine kidney). The 1-10 µg/ml toxin A, with molecular weight of 52 KDa, in ligated rabbit ileal loop (6 rabbits with maximum of 15 loopes in each animal) showed a series of histopathological changes leading to inflammation, fluid or bloody fluid accumulation, mucous and villi disraption in lamina properia. Different concentration of toxin B (MW=60KDa) had no effect on fluid accumulation in striped rabbit ileal loop but caused driness and necrosis intensively. Cultured cells exposed to 1 µg/ml toxin B showed a series of cytopathologic changes leading to cell retraction and rounding accompanied by the marginalization of the cell membrane. Enhancement of toxin concentration caused increament of cytopathic effects. Keywords: Clostridium difficile, Pseudomembranous colitis, Toxin A and B, Rabbit ligated ileal loop, Cell cultur

Specific PCR Assay for Rapid and Direct Detection of Neisseria meningitidis in Cerebrospinal Fluid Specimens

Background: Neisseria meninigitidis is one of the most frequently encountered microorganisms associated with central nervous system infections. The aim of this study was to evaluate a PCR-based assay for specific and rapid detection of N. meninigitidis in CSF specimens.  Methods: Since April 2002 to July 2006, 130 CSF specimens were collected from patients suspected of having bacterial meningitis. Bacterial isolation and identification was carried out according to the standard bacteriological methods.  The PCR was used to amplify a 101bp fragment of capsular transport gene A (ctrA) of N. meningitidis. Results: PCR yielded an amplified product with the expected size of 101 base pair fragment. Sensitivity test proved 500 ng of N. meningitidis DNA as the final detection limit and specificity test revealed no cross-reaction for a wide range of res­pira­tory pathogenic organisms. Conclusion: The PCR assay was more sensitive than the bacterial culturing. It might be possible to apply this procedure for rapid diagnosis of meningococci in clinical samples