Elsevier

Journal of Infection

Volume 70, Issue 6, June 2015, Pages 600-608
Journal of Infection

Distribution, virulence-associated genes and antimicrobial resistance of Aeromonas isolates from diarrheal patients and water, China

https://doi.org/10.1016/j.jinf.2014.11.004Get rights and content

Highlights

  • This is the first report of Aeromonas infection on a large scale of specimens in China.

  • The distribution of Aeromonas species in clinical and environmental samples is different.

  • The resistance to most of antibiotics was higher in strains from the water than those from stools.

  • Aquatic Aeromonas has acquired a wide of antibiotic resistance compared to clinical sources.

Summary

Objectives

To determine the prevalence of Aeromonas infections in diarrheal patients, the distribution of virulence-associated genes and antibiotic resistance among different Aeromonas species in China.

Methods

We conducted continual active surveillance aimed on Aeromonas from diarrheal patients and aquatic samples. Aeromonas strains were identified by biochemical tests, further confirmed to species level by a multilocus phylogenetic analysis. Potential virulence genes were detected by PCR. Antibiotics susceptibility testing was carried based on the minimal inhibitory concentration.

Results

From 5069 samples (stool specimens, n = 4529; water samples, n = 540) in China, 257 Aeromonas isolates [stools, n = 193 (4.3%); water, n = 64 (11.9%)] were identified by biochemical tests. The most common species from stools and water were Aeromonas veronii (42.5%) and Aeromonas caviae (37.5%), respectively. Distribution of five potential genes were significantly different between stool and water samples, two genes (ast and alt) were higher in stool than in water samples (P < 0.01). Meanwhile, three species (A. veronii, A. caviae and Aeromonas aquariorum) account for the six most prevalent combination patterns of potential genes. Furthermore, strains resistant to nine antibiotics was markedly higher in strains isolated from water than those from stools (P ≤ 0.003); in contrast, resistance to only two antibiotics was higher in strains isolated from stools compared to those from water. In addition, strains containing multiple antibiotic resistance (MAR) from stools (8.6%; 16/187) and water (30.2%; 19/63) were resistant to ten or more antibiotics.

Conclusion

Our study highlights the multiple factors involved in the pathogenesis of Aeromonas and reveals that environmental Aeromonas has acquired a wide range of MAR compared to those from clinical sources.

Section snippets

Active surveillance of Aeromonas

Stool specimens were collected from diarrheal patients admitted to sixteen hospitals in the city of Shanghai, China, from June 25, 2010 to Dec. 31, 2012. Patients age from 5 month to 82 years (mean age 42.1 ± 19.2). Specimens were collected by rectal swabs in Cary–Blair transport media and then transported to the laboratories of the Pudong District Center for Disease Prevention and Control (CDC), Shanghai, and the Shanghai Public Health Clinical Center, Fudan University. For the isolation of

Prevalence of Aeromonas and co-infection of active surveillance

We collected 5069 specimens in our active surveillance, including 4529 stool specimens from diarrheal patients and 540 aquatic samples. By traditional biochemical tests: oxidase positive, have facultative anaerobic metabolism, resistance to O/129 (150 μg) (Oxoid), and API-20E system (BioMérieux, France), 193 (4.3%) samples from diarrheal patients and 64 (11.9%) samples from the aquatic environment were identified as the genus level of Aeromonas strains.

For diarrheal patients, Aeromonas was

Discussion

Our active surveillance indicated the wide-spread distribution of Aeromonas species in aquatic environments, which were the major sources of contamination in acquired Aeromonas infections.1 The percentage of Aeromonas-positive samples from diarrheal patients was 4.5%, which is similar to the rate in other countries.3, 18 Here, we did not find proof of outbreaks caused by Aeromonas alone, so the role of Aeromonas as an etiologic agent of diarrhea is still to be a controversial issue,19 further

Acknowledgments

This work was supported by the Priority Project on Infectious Disease Control and Prevention (2008ZX10004-008, 201202006, 2012ZX10004215, 2012ZX10004-201 and 2013ZX10004221-004) from the Ministry of Health, China, Key discipline construction of health system in Pudong New Area, Shanghai, China (No. PWZxk2010-09).

References (37)

  • J.M. Janda et al.

    The genus Aeromonas: taxonomy, pathogenicity, and infection

    Clin Microbiol Rev

    (2010)
  • M.J. Figueras et al.

    Clinical relevance of the recently described species Aeromonas aquariorum

    J Clin Microbiol

    (2009)
  • M. Aravena-Roman et al.

    Aeromonas aquariorum is widely distributed in clinical and environmental specimens and can be misidentified as Aeromonas hydrophila

    J Clin Microbiol

    (2011)
  • H.X. Liu et al.

    Analysis of reported infectious diarrhea (other than cholera, dysentery, typhoid and paratyphoid) in China in 2011

    Zhonghua Yu Fang Yi Xue Za Zhi

    (2013)
  • R. Hao et al.

    Diversity of pathogens responsible for acute diarrheal disease in China

    Clin Infect Dis

    (2013)
  • H.B. Yu et al.

    A type III secretion system is required for Aeromonas hydrophila AH-1 pathogenesis

    Infect Immun

    (2004)
  • M.R. Chacon et al.

    Type III secretion system genes in clinical Aeromonas isolates

    J Clin Microbiol

    (2004)
  • Y. Gao et al.

    Clinical and molecular epidemiologic analyses of norovirus-associated sporadic gastroenteritis in adults from Beijing, China

    J Med Virol

    (2011)
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