Limited performance of MALDI‐TOF for identification of fish <i>Aeromonas</i> isolates at species level

Cerda, Ignacio Alejandro; Fernández-Bravo, Ana; Domı́nguez, Lucas; Figueras, María José; Fernández‐Garayzábal, J. F.; Vela, A. I.

doi:10.1111/jfd.12837

Cited by 29 publications

(21 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main limitation of the latter method is the need to update the database to include the many missing Aeromonas species, such as A. dhakensis or the new species (A. intestinalis, A. crassostreae, A. enterica, and A. aquatilis). A recent study that used MALDI-TOF MS for the characterization of Aeromonas strains isolated from fish [70] demonstrated that the number of correct identifications increased after the addition of 14 new spectra in the MALDI-TOF Biotyper database.…”

Section: Techniques Based On the 16s Rrna Genementioning

confidence: 99%

An Update on the Genus Aeromonas: Taxonomy, Epidemiology, and Pathogenicity

2020

View full text Add to dashboard Cite

The genus Aeromonas belongs to the Aeromonadaceae family and comprises a group of Gram-negative bacteria widely distributed in aquatic environments, with some species able to cause disease in humans, fish, and other aquatic animals. However, bacteria of this genus are isolated from many other habitats, environments, and food products. The taxonomy of this genus is complex when phenotypic identification methods are used because such methods might not correctly identify all the species. On the other hand, molecular methods have proven very reliable, such as using the sequences of concatenated housekeeping genes like gyrB and rpoD or comparing the genomes with the type strains using a genomic index, such as the average nucleotide identity (ANI) or in silico DNA–DNA hybridization (isDDH). So far, 36 species have been described in the genus Aeromonas of which at least 19 are considered emerging pathogens to humans, causing a broad spectrum of infections. Having said that, when classifying 1852 strains that have been reported in various recent clinical cases, 95.4% were identified as only four species: Aeromonas caviae (37.26%), Aeromonas dhakensis (23.49%), Aeromonas veronii (21.54%), and Aeromonas hydrophila (13.07%). Since aeromonads were first associated with human disease, gastroenteritis, bacteremia, and wound infections have dominated. The literature shows that the pathogenic potential of Aeromonas is considered multifactorial and the presence of several virulence factors allows these bacteria to adhere, invade, and destroy the host cells, overcoming the immune host response. Based on current information about the ecology, epidemiology, and pathogenicity of the genus Aeromonas, we should assume that the infections these bacteria produce will remain a great health problem in the future. The ubiquitous distribution of these bacteria and the increasing elderly population, to whom these bacteria are an opportunistic pathogen, will facilitate this problem. In addition, using data from outbreak studies, it has been recognized that in cases of diarrhea, the infective dose of Aeromonas is relatively low. These poorly known bacteria should therefore be considered similarly as enteropathogens like Salmonella and Campylobacter.

show abstract

Section: Techniques Based On the 16s Rrna Genementioning

confidence: 99%

An Update on the Genus Aeromonas: Taxonomy, Epidemiology, and Pathogenicity

2020

View full text Add to dashboard Cite

show abstract

“…Although small differences in intensity and some minor mass variation were observed from different strains, the highly similar spectra hamper a rapid and straightforward identification and misidentification, occurring frequently in routine diagnostic laboratories. In addition, other strains are difficult to completely distinguish by MALDI‐TOF MS including the Burkholderiacepacia complex , 38 the Acinetobacter baumanni group, 39 Streptococcus pneumoniae and Streptococcus mitis/oralis , 40 the Raoultella spp , 41 and so on 42–44 . In this study, Bacillus subtilis was misidentified as Bacillus mojavensis , and on the contrary, in Huang's study, Bacillus mojavensis was misidentified as Bacillus subtilis 45 .…”

Section: Discussionmentioning

confidence: 62%

Evaluation of three sample preparation methods for the identification of clinical strains by using two MALDI‐TOF MS systems

Wang

Cai

et al. 2021

J Mass Spectrom

View full text Add to dashboard Cite

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) has revolutionized the microbial identification, especially in the clinical microbiology laboratories. However, although numerous studies on the identification of microorganisms by MALDI‐TOF MS have been reported previously, few studies focused on the effect of pretreatment on identification. Due to the sensitivity of MALDI‐TOF MS, different preparation methods will lead to changes in microbial protein fingerprints. In this study, for evaluating a more appropriate preparation method for the clinical microbiology identification, we analyzed the performance of three sample preparation methods on two different MALDI‐TOF MS systems. A total of 321 clinical isolates, 127 species, were employed in the comparative study of three different sample preparation methods including the direct colony transfer method (DCTM), the on‐target extraction method (OTEM), and the in‐tube extraction method (ITEM) compatible with MALDI‐TOF MS. All isolates were tested on the Microflex LT and Autof ms1000 devices. The spectra were analyzed using the Bruker biotyper and the Autof ms1000 systems. The results were confirmed by 16/18S rRNA sequencing. Results reveal that the accuracies of isolates identification by Bruker biotyper successfully identified 83.8%, 96.0%, and 95.3% after performing the DCTM, OTEM, and ITEM, respectively, while the Autof ms1000 identified 97.5%, 100%, and 99.7%. These data suggested that the identification rates are comparable among the three preparation methods using the Autof ms1000 and Bruker microflex LT systems but the OTEM is more suitable and necessary for clinical application, owing to its key advantages of simplicity and accuracy.

show abstract

“…The MALDI-TOF is a fast and useful tool employed in many hospitals for the fast identification of bacteria, including those of the genus Aeromonas and it was shown to be more precise than the phenotypic methods [21,22]. The validation of MALDI-TOF was carried out by comparing the obtained results with those of molecular reference methods for the Aeromonas identification, such as the sequences of housekeeping genes [21,22]. The fact that the Biotyper database has few representatives of just a single representative of each species can hinder the correct identification of the species [21,22].…”

Section: Discussionmentioning

confidence: 99%

A Case of Aeromonas trota in an Immunocompromised Patient with Diarrhea

et al. 2020

View full text Add to dashboard Cite

According to recent literature, 95.4% of the Aeromonas strains associated with human clinical cases correspond to four species: Aeromonas caviae, Aeromonas dhakensis, Aeromonas veronii and Aeromonas hydrophila. However, other less prevalent species such as Aeromonas trota, are also described from clinical samples. Based on its low incidence, the latter species can be regarded as rare and it is the only Aeromonas species susceptible to ampicillin. From the taxonomic point of view, A. trota is considered a synonym of the species Aeromonas enteropelogenes. The objective of this study is to present a new clinical case associated with A. trota in order to increase the knowledge about this species. The strain was recovered from the feces of a 69-year-old patient with a diarrheal syndrome and peritoneal psammocarcinoma. The preliminary identification as Aeromonas sp. was obtained with the API 20E, but it was characterized as Aeromonas jandei and also as Aeromonas enteropelogenes with different scores with the matrix-assisted laser desorption ionization time of flight (MALDI-TOF). Based on the sequence of the rpoD gene, it was confirmed to be A. trota. The antimicrobial resistance pattern showed that the strain was susceptible to ampicillin, penicillins in combination with beta-lactamase inhibitors, quinolones, carbapenems, aminoglycosides and cephalosporins, except cephalothin. In conclusion, the recognition of an Aeromonas strain susceptible to ampicillin should alert the clinical microbiologist of the possible involvement of this rare species. Furthermore, the MALDI-TOF database should be updated indicating that the species A. enteropelogenes, is a synonym of A. trota.

show abstract

Limited performance of MALDI‐TOF for identification of fish Aeromonas isolates at species level

Cited by 29 publications

References 34 publications

An Update on the Genus Aeromonas: Taxonomy, Epidemiology, and Pathogenicity

An Update on the Genus Aeromonas: Taxonomy, Epidemiology, and Pathogenicity

Evaluation of three sample preparation methods for the identification of clinical strains by using two MALDI‐TOF MS systems

A Case of Aeromonas trota in an Immunocompromised Patient with Diarrhea

Contact Info

Product

Resources

About