Evaluation of the DiversiLab System for Detection of Hospital Outbreaks of Infections by Different Bacterial Species

Abstract

Many bacterial typing methods are specific for one species only, time-consuming, or poorly reproducible. DiversiLab (DL; bioMérieux) potentially overcomes these limitations. In this study, we evaluated the DL system for the identification of hospital outbreaks of a number bacterial species. Appropriately typed clinical isolates were tested with DL. DL typing agreed with pulsed-field gel electrophoresis (PFGE) for Acinetobacter (n ‫؍‬ 26) and Stenotrophomonas maltophilia (n ‫؍‬ 13) isolates. With two exceptions, DL typing of Klebsiella isolates (n ‫؍‬ 23) also correlated with PFGE, and in addition, PFGE-nontypeable (PFGE-NT) isolates could be typed. Enterobacter (n ‫؍‬ 28) results also correlated with PFGE results; also, PFGE-NT isolates could be clustered. In a larger study (n ‫؍‬ 270), a cluster of 30 isolates was observed that could be subdivided by PFGE. The results for Escherichia coli (n ‫؍‬ 38) correlated less well with an experimental multilocus variable number of tandem repeats analysis (MLVA) scheme. Pseudomonas aeruginosa (n ‫؍‬ 52) showed only a limited number of amplification products for most isolates. When multiple Pseudomonas isolates were assigned to a single type in DL, all except one showed multiple multilocus sequence types. Methicillin-resistant Staphylococcus aureus generally also showed a limited number of amplification products. Isolates that belonged to different outbreaks by other typing methods, including PFGE, spa typing, and MLVA, were grouped together in a number of cases. For Enterococcus faecium, the limited variability of the amplification products obtained made interpretation difficult and correlation with MLVA and esp gene typing was poor. All of the results are reflected in Simpson's index of diversity and adjusted Rand's and Wallace's coefficients. DL is a useful tool to help identify hospital outbreaks of Acinetobacter spp., S. maltophilia, the Enterobacter cloacae complex, Klebsiella spp., and, to a somewhat lesser extent, E. coli. In our study, DL was inadequate for P. aeruginosa, E. faecium, and MRSA. However, it should be noted that for the identification of outbreaks, epidemiological data should be combined with typing results.

Overview of molecular typing methods for outbreak detection and epidemiological surveillance

“…The view that DiversiLab can be insufficiently discriminative for typing some bacterial species, including MRSA, in outbreak settings was confirmed by Babouee et al [27]. The results obtained by Overdevest and colleagues [26], who evaluated the performance of DiversiLab, were also in line with the findings reported by Fluit et al [25], except for the conclusions regarding P. aeruginosa. Deplano and colleagues [24] have demonstrated excellent epidemiological concordance of the results produced by DiversiLab by correctly linking all outbreak-related isolates of vancomycinresistant E. faecium (VREF), Klebsiella pneumoniae, Acinetobacter baumannii, and P. aeruginosa.…”

“…The resulting data are automatically collected, normalised and analysed by the DiversiLab software. A number of studies have evaluated the usefulness of DiversiLab by comparing its performance with current standard typing methods using well-characterised collections of outbreak-related and epidemiologically unrelated bacterial isolates [24][25][26]. These studies have shown that the DiversiLab system is simple, easy to perform, rapid, reproducible, endowed with full typeability and applicable to a wide range of microorganisms.…”

“…The authors concluded that for most bacterial species, in case of a suspected outbreak in hospital settings, DiversiLab is useful especially in first-line outbreak detection. In particular, Fluit and colleagues [25] have shown that DiversiLab is a useful tool for identification of hospital outbreaks of Acinetobacter spp., Stenotrophomonas maltophilia, Enterobacter cloacae, Klebsiella spp., and Escherichia coli, but that it is inadequate for Pseudomonas aeruginosa, Enterococcus faecium, and methicillin-resistant Staphylococcus aureus (MRSA). The view that DiversiLab can be insufficiently discriminative for typing some bacterial species, including MRSA, in outbreak settings was confirmed by Babouee et al [27].…”

Genetic relatedness of clinical and environmental Acinetobacter baumanii isolates from an intensive care unit outbreak

“…In this study we have utilized the semiautomated DiversiLab repPCR system which is a rapid and reproducible system that has been shown to be very useful for the identification of clonal relationship particularly during an outbreak. Its discriminating power has been compared with other genotyping methods for different pathogens and found to be comparable and higher in some instances [24]. The combination of the rep-PCR method with epidemiological investigation provides data on understanding the dynamics of the outbreak.…”

Genotyping Techniques for Determining the Diversity of Microorganisms

“…DL is a useful tool to help identify hospital outbreaks of Acinetobacter spp., S. maltophilia, the Enterobacter cloacae complex, Klebsiella spp., and, to a somewhat lesser extent, E. coli. DL was inadequate for P. aeruginosa, Enterococcus faecium, and MRSA (Fluit et al, 2010).…”