Comparison of molecular typing methods for the analyses of Acinetobacter baumannii from ICU patients

Abstract

Acinetobacter baumannii has emerged as an important cause of healthcare-associated infections causing great morbidity and mortality. Despite its clinical importance, it is still unknown which molecular typing method is the best to determine or confirm institutional outbreaks as well as to identify epidemiologically related isolates from different geographical areas. To determine the most discriminatory molecular typing method, we isolated A. baumannii from perianal swabs collected from intensive care unit (ICU) patients in a cohort study during 2002 and 2008. Strains from each year were analyzed by pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and multi-locus variable-number tandem repeat analysis (MLVA). Genetic relatedness of the isolates was consistent between PFGE and MLST as well as between analyses of loci containing MLVA and MLST. Our data show that PFGE and MLVA are similar when discriminating between isolates and are both good methods to use when questioning whether two isolates are indistinguishable.

Genetic relatedness of serial rectal isolates of Acinetobacter baumannii in an adult intensive care unit of a tertiary hospital in Kuwait

“…In addition, there were singletons: ST1980 and those representing the six new STs. Our findings are supported by previous studies that have shown that PFGE typing is more discriminatory than MLST typing or eBURST analysis [37].…”

High prevalence and clonal dissemination of OXA-72-producing Acinetobacter baumannii in a Chinese hospital: a cross sectional study

“…There are some limitations for this study. The first is the inclusion criteria of Acb complex strains, it has been demonstrated that a single patient may have more than one genetic type of Acinetobacter [ 42 , 43 ]. To avoid the problem of duplicate data, this study adopted a simple inclusion method of allowing only a single isolate per patient.…”

Significant spread of extensively drug-resistant Acinetobacter baumannii genotypes of clonal complex 92 among intensive care unit patients in a university hospital in southern Iran

“…These discrepancies may be due to minor differences in the MLVA protocol employed, but may also be explained by the knowledge that individual VNTR loci can evolve rapidly. We used gel electrophoresis in our study, a method that inherently includes a manual reading and is thus associated with greater variation in the results compared to the high precision offered by capillary electrophoresis [38].…”