Abstract
BackgroundClinical characteristics (taxonomy, virulence genes and antimicrobial resistance ) of Aeromonas in isolated from extra-intestinal and intestinal infections were investigated to describe epidemiology, associated virulence factors and optimal therapy options.MethodsClinical samples (n = 115) of Aeromonas were collected from a general hospital in Beijing between the period 2015 and 2017. Taxonomy was investigate by Multilocus phylogenetic analysis (MLPA), 10 putative virulence factors by use of polymerase chain reaction (PCR) and antimicrobial resistance to 15 antibiotics by use of the microbroth dilution method.ResultsThe most common species of Aeromonas detected in samples of intestinal tract included; A. caviae (43.9%), A. veronii (35.7%), and A. dhakensis (12.2%). Prevalent species of Aeromonas collected from extra-intestinal infections included; A. hydrophila (29.4%), A. caviae (29.4%), and A. dhakensis (23.5%). A. hydrophila were detected in 1% of stool samples and 29.4% (5/17) of extra-intestinal infections. A. hydrophila strains in extra-intestinal infections were related to malignancy. The most common medical conditions among patients with Aeromonas infections included malignancy and liver-transplant related cholecystitis. Multiple drug resistance (MDR) was prevalent in extra-intestinal isolates (82.3%, 14/17) and was greater than the prevalence in intestinal isolates (30.6%, 30/98) (P < 0.05). Resistant rates of extra-intestinal isolates were 70.6, 35.3, 23.5 and 5.9% for ceftriaxone, ciprofloxacin, gentamicin and imipenem, respectively, and were higher than found in previous studies. Despite differences in the number and type of virulence genes among samples of Aeromonas, no significant correlation was found between invasion and virulent genes in intestinal or extra-intestinal infections.ConclusionsOverall results of this study support a role for Aeromonas spp. as a potential causative infectious agent of gastroenteritis, and malignancy, liver cirrhosis, post liver transplantation in immunocompromised patients. A. hydrophila was more prevalent in samples of extra-intestinal infections when compared to samples of intestinal infections, and was especially prominent in samples of patients presenting with malignancy. Aeromonas isolates from extra-intestinal samples had high rates of drug resistance but 3rd generation cephalosporins, fluoroquinolones and aminoglycosides remain as options to treat severe diarrhea. However, increasing MDR of extra-intestinal infection samples warrants monitoring.
Highlights
Clinical characteristics of Aeromonas in isolated from extra-intestinal and intestinal infections were investigated to describe epidemiology, associated virulence factors and optimal therapy options
The genus Aeromonas is a common, gram-negative, facultative anaerobe, coccobacillary-to-bacillary bacteria that belongs to Aeromonadaceae [1].The genus Aeromonas is comprised of mesophiles and psychrophiles which can cause a number of diseases to warm and cold-blooded animals [2]
Aeromonas have a complex taxonomy and the genus is comprised of over 30 species, their identification has been limited by use of conventional biochemical identification methods such as matrix-assisted laser desorption/ ionization time of flight masss spectrometry (MALDI-TOF MS), and 16S ribosomal ribonucleic acid sequencing [5,6,7,8]
Summary
Clinical characteristics (taxonomy, virulence genes and antimicrobial resistance ) of Aeromonas in isolated from extra-intestinal and intestinal infections were investigated to describe epidemiology, associated virulence factors and optimal therapy options. Aeromonas have a complex taxonomy and the genus is comprised of over 30 species, their identification has been limited by use of conventional biochemical identification methods such as matrix-assisted laser desorption/ ionization time of flight masss spectrometry (MALDI-TOF MS), and 16S ribosomal ribonucleic acid (rRNA) sequencing [5,6,7,8]. To this end, the use of 5 or more housekeeping genes has been demonstrated as an effective approach for multilocus phylogenetic analysis (MLPA) and species identification of Aeromonas spp. Caution must be exercised as A. dhakensis can be misidentified as A. hydrophila by use of some phenotypic methods [12] and MLPA is suggeted for molecular subtyping [13, 14]
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