Aerobic Bacteria and Fungi on the Surfaces of a Tertiary Assistance Hospital from Northern Brazil

Background and Objectives: It is very common that hospital environment is colonised by microorganisms. This colonisation is a potential threat for hospitalised patients, especially in high-risk services. Quantification of microorganisms from surfaces is an important strategy to control the hospital infection.

Materials and Methods: Total 70 samples were collected and seeded in the Mueller Hinton and Sabouraud Agar culture media. Media cultures in Petri dishes were incubated and microbial growth was quantified (CFU/cm2). Bacteria cultures were characterised by Gram stain. Fungal cultures were submitted for micromorphological evaluation and CHROMagar™ incubation.

Results: Bacterial population higher than 250 CFU/cm2 was found in 11 out of 70 samples. Fungi were found in 3 out of 70 samples. Common manipulation surfaces as water drinking unit, shelf and water tap presented the highest contamination rates. Bacterial cultures (n= 95) showed mostly the presence of Gram-negative bacteria (81%). In addition, regarding the fungal cultures (n= 129) mostly filamentous fungi (72%), from Aspergillus genera were obtained.

Conclusion: Most of the investigated hospital surfaces presented low contamination (< 5 CFU/cm2). However, microbiological studies should be regular in critical areas in order to reinforce measures to control and prevent hospital infection.