Clostridium difficile infections in Finland, 2008-2015: trends, diagnostics and ribotypes

Area of Science:

• Clinical microbiology
• Infectious disease epidemiology

Background:

• Clostridium difficile infection (CDI) diagnosis and surveillance are critical for public health.
• Regional variations in diagnostic practices can impact reported incidence rates.

Purpose of the Study:

• To evaluate Clostridium difficile (CD) diagnostic methods and activity in Finnish laboratories from 2006-2015.
• To correlate diagnostic trends with surveillance and molecular typing data.
• To assess the impact of diagnostic method changes on CDI incidence.

Main Methods:

• Analysis of diagnostic activity and method usage (culture, EIA, NAAT) in Finnish clinical microbiology laboratories.
• Comparison with National Infectious Disease Register (NIDR) surveillance data.
• Polymerase chain reaction (PCR) ribotyping of CD isolates.

Main Results:

• Significant regional variation in CD diagnostic activity and positivity rates observed.
• Nucleic acid amplification testing (NAAT) users tested more patients and identified more cases.
• Transition to NAAT did not lead to a significant increase in observed CDI incidence.
• PCR ribotyping identified 146 distinct profiles, with decreasing prevalence of RT027 and increasing RT078.

Conclusions:

• Persistent regional differences in diagnostic strategies complicate CDI epidemiology comparisons.
• The adoption of NAAT has increased case detection but not significantly altered overall CDI incidence trends.
• Continued monitoring and standardization of diagnostic approaches are essential.