Po-Lin Chen1, Pei-Jane Tsai2, Chang-Shi Chen3, Ying-Chuan Lu4, Hung-Mo Chen4, Nan-Yao Lee5, Ching-Chi Lee5, Chia-Wen Li5, Ming-Chi Li5, Chi-Jung Wu6, Wen-Chien Ko7. 1. Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Graduate Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan. 2. Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan; Research Center of Infectious Disease and Signaling, National Cheng Kung University, Tainan, Taiwan. 3. Department of Biochemistry and Molecular Biology, National Cheng Kung University, Tainan, Taiwan. 4. Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan. 5. Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan. 6. National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan. Electronic address: wu.chijung@msa.hinet.net. 7. Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Department of Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan. Electronic address: winston3415@gmail.com.
Abstract
BACKGROUND: Although aeromonads are important pathogens causing invasive infections in southern Taiwan, Aeromonas-associated intestinal infections have been rarely mentioned. PURPOSE: The aim of this study was to understand the frequency of isolation and clinical significance of aeromonads recovered from adult stool samples in southern Taiwan. METHODS: During a 15-month study period, 514 adults with diarrhea and 167 asymptomatic controls were prospectively screened for the presence of aeromonads in stools. The identity of Aeromonas species was determined by the rpoD sequencing. Clinical information was retrieved from medical records, and in vitro cytotoxicity assay and polymerase chain reaction detection of putative virulent genes were performed. RESULTS: Thirteen (2.5 %) of 514 diarrheal patients and six (3.6%) of 167 asymptomatic controls had Aeromonas isolates in their stools. Of 11 diarrheal patients with available clinical information, Aeromonas veronii, the predominant species, was noted in six patients, and another potential enteropathogen was present in four patients. The cytotoxicity of A. veronii isolates to the HT-29 cell line was more potent in the isolates from diarrheal patients than those from asymptomatic controls (p = 0.015). The cytotoxicity of A. veronii isolates was more potent than that of A. caviae from symptomatic patients (p = 0.001). Putative virulence markers, including AHCYTONE, ascV, ascF-ascG, and aexT, were detected exclusively in A. veronii. The presence of the ascV gene was associated with cytotoxicity in A. veronii isolates. All Aeromonas isolates were susceptible to varied antimicrobial agents, except ampicillin/sulbactam. CONCLUSION: A. veronii is the predominant species in stools from individuals with or without diarrhea in southern Taiwan.
BACKGROUND: Although aeromonads are important pathogens causing invasive infections in southern Taiwan, Aeromonas-associated intestinal infections have been rarely mentioned. PURPOSE: The aim of this study was to understand the frequency of isolation and clinical significance of aeromonads recovered from adult stool samples in southern Taiwan. METHODS: During a 15-month study period, 514 adults with diarrhea and 167 asymptomatic controls were prospectively screened for the presence of aeromonads in stools. The identity of Aeromonas species was determined by the rpoD sequencing. Clinical information was retrieved from medical records, and in vitro cytotoxicity assay and polymerase chain reaction detection of putative virulent genes were performed. RESULTS: Thirteen (2.5 %) of 514 diarrhealpatients and six (3.6%) of 167 asymptomatic controls had Aeromonas isolates in their stools. Of 11 diarrhealpatients with available clinical information, Aeromonas veronii, the predominant species, was noted in six patients, and another potential enteropathogen was present in four patients. The cytotoxicity of A. veronii isolates to the HT-29 cell line was more potent in the isolates from diarrhealpatients than those from asymptomatic controls (p = 0.015). The cytotoxicity of A. veronii isolates was more potent than that of A. caviae from symptomatic patients (p = 0.001). Putative virulence markers, including AHCYTONE, ascV, ascF-ascG, and aexT, were detected exclusively in A. veronii. The presence of the ascV gene was associated with cytotoxicity in A. veronii isolates. All Aeromonas isolates were susceptible to varied antimicrobial agents, except ampicillin/sulbactam. CONCLUSION:A. veronii is the predominant species in stools from individuals with or without diarrhea in southern Taiwan.