Identity, virulence genes, and clonal relatedness of Aeromonas isolates from patients with diarrhea and drinking water

Pablos, M; Remacha, María Antonia; Rodríguez-Calleja, José M.; Santos, Jesús A.; Otero, Andrés; García-López, María-Luisa

doi:10.1007/s10096-010-0982-3

Cited by 58 publications

(60 citation statements)

References 44 publications

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“…One possible explanation is horizontal acquisition of stx by Aeromonas hydrophila, which has been reported (29). Alternatively, the Aeromonas-positive specimens may have been coinfected with a strain of STEC that could not be cultured, since mixed infections of Aeromonas with stool pathogens have been described (30). Because this possibility could not be excluded and the CDPH was able to confirm stx positivity, these samples were considered true-stx-positive samples.…”

Section: Discussionmentioning

confidence: 99%

A Sensitive Multiplex, Real-Time PCR Assay for Prospective Detection of Shiga Toxin-Producing Escherichia coli from Stool Samples Reveals Similar Incidences but Variable Severities of Non-O157 and O157 Infections in Northern California

et al. 2013

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dRapid and accurate detection of Shiga toxin-producing Escherichia coli (STEC) of all serotypes from patients with diarrhea is critical for medical management and for the prevention of ongoing transmission. In this prospective study, we assessed the performance of a multiplex, real-time PCR assay targeting stx 1 and stx 2 for the detection of O157 and non-O157 STEC in diarrheal stool samples enriched in Gram-negative broth. We show that the assay is 100% sensitive (95% confidence interval [CI], 89.1% to 100%) and 98.5% specific (95% CI, 90.6% to 99.9%) based on a panel of 40 known STEC-positive specimens and 65 known negative specimens. During a 2-year postvalidation period, the assay detected more positive samples from patients in northern California than did culture and PCR testing performed at a public health reference laboratory, with a positive predictive value of 95.6% (95% CI, 87.6% to 99.1%). Serotyping data showed an incidence rate of 51.2% for non-O157 STEC strains, with 5.8% of patients (1/17) with non-O157 strains and 42.9% (6/14) with O157 strains (P ‫؍‬ 0.03) developing hemolytic-uremic syndrome. The findings from this study underscore the recommendations of the CDC for laboratories to test all diarrheal stool samples from patients with acute community-acquired diarrhea for non-O157 STEC in addition to the O157 serotype by using a sensitive assay. Additionally, a survey of 17 clinical laboratories in northern California demonstrated that nearly 50% did not screen all stool specimens for the presence of Shiga toxins, indicating that many clinical microbiology laboratories still do not routinely screen all stool specimens for the presence of Shiga toxins as recommended in the 2009 CDC guidelines. Shiga toxin-producing Escherichia coli (STEC) infections are a major cause of bacterial gastroenteritis throughout the world and can be complicated by hemorrhagic colitis and hemolyticuremic syndrome (HUS) (1, 2). Although previously the majority of reported cases were attributed to E. coli O157:H7 and many recent studies indicate higher incidence rates of HUS associated with E. coli O157:H7 (3, 4), non-O157 STEC serotypes are emerging as important etiological agents of both sporadic cases and community outbreaks of diarrhea (3-8). Most notably, in May and June 2011, a large outbreak of E. coli O104:H4-associated diarrheal illness in Germany led to HUS in over 800 patients, many of whom were adults, and ultimately resulted in 54 deaths (5, 9). This outbreak and others have underscored the fact that severe disease and HUS can occur in cases related to non-O157 or O157 E. coli strains and that adults as well as children are susceptible to these complications (8-10). Timely laboratory identification of STEC has important implications for outbreak containment and patient management, including prompt parenteral hydration, monitoring for development of HUS, and avoidance of antibiotics and antidiarrheal agents, which can exacerbate disease (1). Importantly, a number of studies have shown that STECrelated illnesses...

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Section: Discussionmentioning

confidence: 99%

A Sensitive Multiplex, Real-Time PCR Assay for Prospective Detection of Shiga Toxin-Producing Escherichia coli from Stool Samples Reveals Similar Incidences but Variable Severities of Non-O157 and O157 Infections in Northern California

et al. 2013

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“…HlyA is a hemolysin like β-hemolytic Vibrio cholera [13]. In a previous study, Ottaviani et al [19] found the detection rate of the aerA gene to be 92.7% and 88% in food and clinical Aeromonas isolates, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of aerA, hlyA, alt, and ast genes encoding hemolytic, cytotoxic, cytotonic, and enterotoxic activities may contribute to diarrhealrelated virulence [13]. Cytotoxins (aerolysin, hemolysin and multifunctional repeat-in-toxin) produced by A. hydrophila, a node-like receptor family, trigger caspase-1 activation by means of pyrin domain containing 3 (NLRP 3 ) inflammasomes in macrophages, and this triggers pyroptosis as a form of proinflammatory necrosis in macrophages [20].…”

Section: Discussionmentioning

confidence: 99%

“…The pathogenicity of Aeromonas spp. is multifactorial and complex and may include products of a number of different genes acting individually or collectively.The presence of aerA, hlyA, alt, and ast genes could contribute to diarrhea-related virulence [13]. Shiga toxins (STX1 and STX2) coded by stx1 and stx2 genes are important virulence factors in the pathogenesis of gastroenteritis, hemorrhagic colitis, and hemolyticuremic syndrome (HUS) [14], and the ascF genecoded putative type III secretion system also plays important role in pathogenicity [15].…”

Section: Introductionmentioning

confidence: 99%

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Detection of putative virulence genes in Aeromonas isolates from humans and animals

Körkoca

Alan

Bozari

et al. 2014

J Infect Dev Ctries

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Introduction: Aeromonas are food-and water-borne bacteria that are considered to be zoonotic human pathogens. This study aimed to investigate the presence of genes associated with virulence in human and animal Aeromonas isolates and the potential role of animal isolates with regards to human Aeromonas infections. Methodology: The presence of aerA, hlyA, alt, ast, laf, ascF-G, stx1 and stx2 putative virulence genes in 40 human and animal Aeromonas isolates (16 human and 24 animal isolates) were examined by polymerase chain reaction (PCR). DNA fragments of expected sizes were purified and sequenced. BLAST in the NCBI was used to verify any amplified products. Results: PCR screening showed that hlyA, alt, and laf genes were determined at ratios of 6.25%, 50%, and 6.25%, respectively, in human isolates. The ratios of hlyA, alt, ascF-G, laf, stx2, and stx1 genes in animal isolates were 58.3%, 20.83%, 33.3%, 20.83%, 8.33%, and 4.17%, respectively. Neither aerA nor ast genes were detected in any isolates. Any one of eight putative virulence genes was not detected in seven human and eight animal isolates in the study. Conclusions: The current study is the first to investigate the presence of the virulence gene in gull Aeromonas isolates. The manifestation of the presence of the virulence gene and gene combinations was considerable, especially in fish and gull isolates when compared with clinical human isolates. The current study demonstrates the potential importance of fish and gulls in terms of human Aeromonas infections.

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“…Recently, several studies have investigated the role of Aeromonas species in human infections (34,43,64,61) and the role of the involved virulence factors (6,15,49,62). Several recent studies reported the involved virulence factors in fish infections (11,17,36).…”

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confidence: 99%

Determination of Microbial Diversity of Aeromonas Strains on the Basis of Multilocus Sequence Typing, Phenotype, and Presence of Putative Virulence Genes

Martino

Fasolato

Montemurro

et al. 2011

Appl Environ Microbiol

107

110

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The genus Aeromonas has been described as comprising several species associated with the aquatic environment, which represents their principal reservoir. Aeromonas spp. are commonly isolated from diseased and healthy fish, but the involvement of such bacteria in human infection and gastroenteritis has frequently been reported. The primary challenge in establishing an unequivocal link between the Aeromonas genus and pathogenesis in humans is the extremely complicated taxonomy. With the aim of clarifying taxonomic relationships among the strains and phenotypes, a multilocus sequencing approach was developed and applied to characterize 23 type and reference strains of Aeromonas spp. and a collection of 77 field strains isolated from fish, crustaceans, and mollusks. All strains were also screened for putative determinants of virulence by PCR (ast, ahh1, act, asa1, eno, ascV, and aexT) and the production of acylated homoserine lactones (AHLs). In addition, the phenotypic fingerprinting obtained from 29 biochemical tests was submitted to the nonparametric combination (NPC) test methodology to define the statistical differences among the identified genetic clusters. Multilocus sequence typing (MLST) achieved precise strain genotyping, and the phylogenetic analysis of concatenated sequences delineated the relationship among the taxa belonging to the genus Aeromonas, providing a powerful tool for outbreak traceability, host range diffusion, and ecological studies. The NPC test showed the feasibility of phenotypic differentiation among the majority of the MLST clusters by using a selection of tests or the entire biochemical fingerprinting. A Web-based MLST sequence database (http: //pubmlst.org/aeromonas) specific for the Aeromonas genus was developed and implemented with all the results.

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Identity, virulence genes, and clonal relatedness of Aeromonas isolates from patients with diarrhea and drinking water

Cited by 58 publications

References 44 publications

A Sensitive Multiplex, Real-Time PCR Assay for Prospective Detection of Shiga Toxin-Producing Escherichia coli from Stool Samples Reveals Similar Incidences but Variable Severities of Non-O157 and O157 Infections in Northern California

A Sensitive Multiplex, Real-Time PCR Assay for Prospective Detection of Shiga Toxin-Producing Escherichia coli from Stool Samples Reveals Similar Incidences but Variable Severities of Non-O157 and O157 Infections in Northern California

Detection of putative virulence genes in Aeromonas isolates from humans and animals

Determination of Microbial Diversity of Aeromonas Strains on the Basis of Multilocus Sequence Typing, Phenotype, and Presence of Putative Virulence Genes

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