Comparison between adenosine triphosphate bioluminescence and aerobic colony count to assess surface sanitation in the hospital environment

Background: Adenosine triphosphate bioluminescence produced by the firefly luciferase has been successfullyintroduced to verify cleaning procedures in the food industry according to the Hazard Analysis Critical Control Pointprogram.Our aim was to evaluate the reliability of bioluminescence as a tool to monitor the effectiveness of sanitation in healthcaresettings, in comparison with the microbiological gold standard.Methods: 614 surfaces of various material were randomly sampled in Policlinico University Hospital units in Palermo,Italy, to detect adenosine triphosphate bioluminescence and aerobic colony count. Linear regression model andPearson correlation coefficient were used to estimate the relationship between the two variables of the study.Results: Aerobic colony count median was 1.71 colony forming units/cm2 (interquartile range = 3.8), whereasadenosine triphosphate median was 59.9 relative light units/cm2 (interquartile range = 128.3). Pearson coefficientR2 was 0.09. Sensitivity and specificity of bioluminescence test with respect to microbiology were 46% and 71%,whereas positive predictive value and negative predictive value were 53% and 65%, respectively.Conclusion: According to our results, there seemed to be no linear correlation between aerobic colony countand adenosine triphosphate values, suggesting that current bioluminescence technology has not any proportionalrelationships with culturable microbes contaminating environmental surfaces in health-care settings

Air microbial contamination in dental clinics: comparison between active and passive methods

The aim of this study was to evaluate the correlation between the microbial air contamination values obtained by active sampling (colony-forming units per cubic metre, CFU/m3) and by passive sampling (Index of microbial air contamination, IMA) and to calculate the corresponding equations. Air sampling was performed in ten dental clinics (DC), before (T0), during (T1) and after (T2) the clinical activity, for five consecutive days, once a month for a period of three months, for a total of 450 air samplings. The correlation was evaluated using the Spearman test, and a p value below 0.05 was considered statistically significant. A statistically significant correlation was found considering both the results obtained from the total observations and from the single sampling times, T0, T1 and T2. Different correlation patterns were observed stratifying by DC. Both methods were able to evaluate the microbial air quality and highlight critical situations; therefore, both can be used with this aim. However, in particular during the activity, passive sampling resulted more sensitive, and for its simplicity, economy and standardization by IMA, as suggested by several authors, can be suggested for routine monitoring

Antimicrobial Resistance in Salmonella Enteritidis, Southern Italy, 1990-1998

During 1990 to 1998, we identified multidrug-resistant isolates of Salmonella Enteritidis in southern Italy. Plasmids containing class I integrons and codifying for synthesis of extended-spectrum ß-lactamases were detected. Active surveillance for resistance to antimicrobial agents is needed to guard against the possible spread of resistant clones

Dispersal of methicillin resistant Staphylococcus aureus (MRSA) in a burn intensive care unit

Methicillin resistant Staphylococcus aureus (MRSA) is a pathogen of special concern in intensive care units (ICUs). The burn units are a very susceptible habitat to colonization and infection events by this organism. In this paper isolation of MRSA from a sepsis case and from samples of the care unit air is described, along with simultaneous circulation of two clones of MRSA. Some peculiar epidemiological features of MRSA in burn intensive care wards are confirmed

Can technical, functional and structural characteristics of dental units predict Legionella pneumophila and Pseudomonas aeruginosa contamination?

Legionella pneumophila and Pseudomonas aeruginosa are common colonizers of water environments, particularly dental unit waterlines. The aim of this study was to assess whether the technical, functional and structural characteristics of dental units can influence the presence and the levels of opportunistic pathogens. Overall, 42 water samples were collected from dental units in a teaching hospital in Palermo, Italy, including 21 samples from the 21 taps supplied by the municipal water distribution system and 21 samples from oral rinsing cups at 21 dental units. L. pneumophila was present in 16 out of 21 water samples (76.2%) from dental units, and the median concentration was higher in samples from oral rinsing cups than in those from taps (P < 0.001). P. aeruginosa was equally distributed in water samples collected from oral rinsing cups and from taps. Some characteristics of dental units (age, number of chairs per room, number of patients per day and water temperature) were slightly associated with the presence of P. aeruginosa, but not with contamination by L. pneumophila. Our experience suggests that L. pneumophila is frequently detected in dental units, as reported in previous studies, whereas P. aeruginosa is not a frequent contaminant. As a consequence, microbiological control of water quality should be routinely performed, and should include the detection of opportunistic pathogens when bacterial contamination is expected