Exploring bacterial diversity in hospital environments by GS-FLX Titanium pyrosequencing

Area of Science:

• Microbiology
• Hospital Epidemiology
• Environmental Health

Background:

• Hospital-acquired infections (HAIs) are a growing concern, particularly in intensive care units (ICUs).
• Understanding the microbial ecology of hospital environments is vital for infection control.
• Inanimate surfaces act as reservoirs for microbial pathogens.

Purpose of the Study:

• To explore and compare bacterial diversity on inanimate surfaces in an ICU ward versus a hospital entrance hall.
• To identify bacterial populations associated with specific hospital microenvironments.
• To investigate the impact of selective pressures on microbial communities within ICUs.

Main Methods:

• Surface swab sampling from ICU and entrance hall locations at the University Hospital A Coruña.
• Amplification of the bacterial 16S rRNA gene hypervariable region.
• High-throughput sequencing using Roche 454 GS-FLX Titanium platform.
• Bioinformatic analysis including OTU clustering and taxonomic classification.

Main Results:

• A total of 16 bacterial phyla were detected across both locations.
• Firmicutes and Actinobacteria were over-represented in the ICU, while Proteobacteria were abundant in both.
• The entrance hall showed higher relative abundance of Proteobacteria, Bacteroidetes, Deinococcus-Thermus, and Cyanobacteria.
• Bacterial diversity was reduced in the ICU compared to the entrance hall.

Conclusions:

• Significant differences in bacterial diversity exist between ICU wards and hospital entrance halls.
• The confined nature and antimicrobial selective pressure in ICUs contribute to reduced microbial diversity.
• This study highlights the utility of deep sequencing for characterizing hospital microbial ecosystems.