THE OCCURRENCE OF BACTERIA ON HOSPITAL WALLS

Reyes Murrieta , Laura Y. Sifuentes, Kelly R. Bright

THE OCCURRENCE OF BACTERIA ON HOSPITAL WALLS

Information on the occurrence of bacteria on walls in health care settings is extremely limited. Opportunistic bacterial pathogens (disease-causing organisms) are the major cause of nosocomial (hospital-acquired) infections. Therefore, the control of bacterial numbers in such environments is important in limiting exposure to patients. The primary objective of this research was to determine the concentrations of bacteria on typical walls in a hospital adult care ward. In addition, the areas that were more likely to be contaminated with bacterial pathogens were determined. Sampling was performed using a sponge stick to recover the bacteria from a 100-cm2 area. Overall bacterial numbers in addition to the nosocomial pathogens methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Streptococcus were determined by culture on agar media and confirmation using biochemical tests. Five sampling locations were chosen (2 adult care patient rooms, 2 waiting rooms, 1 adult care ward hallway). Samples (n=172) were collected from 16 sites in each location bi-weekly for 6 months. The geometric mean for the bacteria recovered from all locations was 223 colony forming units/100 cm2. In general, the bacterial contamination increased with proximity to the floor. Communal areas had higher overall bacterial numbers than the patient rooms (324 vs. 122); nevertheless, 6 pathogenic species were isolated from the patient rooms during the study, whereas only 2 were isolated from the communal areas. Based on our findings, routine cleaning of hospital walls with disinfectants should help to decrease contamination by these pathogens and to reduce the incidence of nosocomial infections.   

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