Molecular validation of clinical Pantoea isolates identified by MALDI-TOF

Abstract

The Enterobacterial genus Pantoea contains both free-living and host-associating species, with considerable debate as to whether documented reports of human infections by members of this species group are accurate. MALDI-TOF-based identification methods are commonly used in clinical laboratories as a rapid means of identification, but its reliability for identification of Pantoea species is unclear. In this study, we carried out cpn60-based molecular typing of 54 clinical isolates that had been identified as Pantoea using MALDI-TOF and other clinical typing methods. We found that 24% had been misidentified, and were actually strains of Citrobacter, Enterobacter, Kosakonia, Klebsiella, Pseudocitrobacter, members of the newly described Erwinia gerundensis, and even several unclassified members of the Enterobacteriaceae. The 40 clinical strains that were confirmed to be Pantoea were identified as Pantoea agglomerans, Pantoea allii, Pantoea dispersa, Pantoea eucalypti, and Pantoea septica as well as the proposed species group, Pantoea latae. Some species groups considered largely environmental or plant-associated, such as P. allii and P. eucalypti were also among clinical specimens. Our results indicate that MALDI-TOF-based identification methods may misidentify strains of the Enterobacteriaceae as Pantoea.

Pantoea Infections in the Neonatal Intensive Care Unit

“…They showed that 24% of clinical isolates were misidentified, with MALDI-TOF misidentifying one of every five strains. They found that P. agglomerans and P. septica are the two correctly identified species [33].…”

Coming from the Wild: Multidrug Resistant Opportunistic Pathogens Presenting a Primary, Not Human-Linked, Environmental Habitat

“…Another Gram-negative genus within the Enterobacteriaceae family is Pantoea , which includes 20 species isolated from different aquatic and terrestrial environments. Although many Pantoea isolates are misidentified, they have been described in association with plants and animals; mainly insects, but also birds, fish, bears, ruminants and importantly, humans [ 367 , 368 , 369 ]. The ability of this bacterial group to compete and survive in different niches has made it attractive for biotechnological uses.…”

“…As it happens with other pathogens with an environmental origin, clinical and environmental isolates are phylogenetically indistinguishable. Even more, Pantoea species considered primarily plant pathogens can be isolated from humans [ 367 , 369 ]. The most prevalent species infecting humans are Pantoea agglomerans and Pantoea septica [ 369 ].…”

“…Even more, Pantoea species considered primarily plant pathogens can be isolated from humans [ 367 , 369 ]. The most prevalent species infecting humans are Pantoea agglomerans and Pantoea septica [ 369 ]. Other clinically-relevant species include Pantoea dispersa , causing bacteraemia and neonatal sepsis [ 373 ], Pantoea brenneri and Pantoea conspicua , isolated from human sputum and blood, respectively [ 374 , 375 ].…”

First Report of Pathogenic Bacterium Kalamiella piersonii Isolated from Urine of a Kidney Stone Patient: Draft Genome and Evidence for Role in Struvite Crystallization

“…The other closely related genus Mixta also has species having association with humans, though the pathogenesis is still not well established [ 16 ]. Some studies also suggest that many clinical isolates of Pantoea are not identified properly; for example, Soutar et al [ 17 ] using MALDI-TOF based identification reclassified a clinical isolate of Pantoea as Mixta calida . Based on this information, we sequenced the genome of the strain YU22 and performed culture-dependant analysis to understand its clinical significance.…”