Qualidade higiênico-sanitária e ocorrência de Aeromonas sp. e Escherichia coli em tilápias comercializadas no varejo

Pós-graduação em Aquicultura - FCAV

Prevalence, distribution and drug resistance of motile aeromonads in freshwater ornamental fishes

The objective of the present study was to assess the prevalence of various motile aeromonads in freshwater ornamental fishes and to elucidate the antibiogram and beta hemolytic activity among the isolates. A total of 120 ornamental fish samples were screened and analyzed for Aeromonas spp. Motile aeromonads were isolated from 37.5% of the ornamental fish samples. Various species of motile aeromonads such as Aeromonas caviae, Aeromonas hydrophila, Aeromonas jandaei, Aeromonas schubertii, Aeromonas sobria, Aeromonas trota and Aeromonas veronii were detected. All the isolates were sensitive to ceftazidime, chloramphenicol, ciprofloxacin and gentamicin. Multiple antibiotic resistance was observed in 58% of the isolates.

Aeromonas spp. isolated from oysters (Crassostrea rhizophorea) from a natural oyster bed, Ceará, Brazil

Between April and October 2002, thirty fortnightly collections of oysters (Crassostrea rhizophorea) from a natural oyster bed at the Cocó River estuary in the Sabiaguaba region (Fortaleza, Ceará, Brazil) were carried out, aiming to isolate Aeromonas spp. strains. Oyster samples were submitted to the direct plating (DP) and the presence/absence (P/A) methods. Aeromonas were identified in 15 (50%) samples analyzed by the DP method and in 13 (43%) analyzed by the P/A method. A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii and Aeromonas sp. were isolated. The predominant species was A. veronii (both biovars), which was identified in 13 (43%) samples, followed by A. media in 11 (37%) and A. caviae in seven (23%). From the 59 strains identified, 28 (48%) presented resistance to at least one of the eight antibiotics tested.

Aeromonas spp. e Plesiomonas shigelloides isoladas a partir de mexilhões (Perna perna) in natura e pré-cozidos no Rio de Janeiro, RJ

O ecossistema aquático é o habitat de mexilhões (Perna perna), animais filtradores que refletem a qualidade ambiental através de análise microbiológica de sua carne. No presente trabalho avaliou-se a presença de patógenos emergentes (Aeromonas hydrophila e Plesiomonas shigelloides), em mexilhões in natura e pré-cozidos coletados por pescadores da Estação Experimental de Cultivo de Mexilhões situada em Jurujuba, Niterói, Rio de Janeiro. Foram analisadas 86 amostras de mexilhões (43 in natura e 43 pré-cozidos) as quais foram submetidas a enriquecimento em Água Peptonada Alcalina (APA) acrescida de 1 e 3% de Cloreto de Sódio (NaCl) e em solução Salina de Butterfield, incubadas a 37ºC por 24 horas. Em seguida, foram semeadas em Ágar Seletivo para Pseudomonas-Aeromonas (GSP), Ágar Tiossulfato Citrato Bile Sacarose (TCBS) e Ágar Inositol Bile Verde Brilhante (IBB). A análise geral dos resultados permitiu a identificação de Areomonas spp e Plesiomonas shigelloides em 86% das amostras de mexilhões in natura e pré-cozidas avaliadas. A posterior caracterização bioquímica permitiu a identificação das espécies Aeromonas media (37,10%), A. hydrophila (15,50%), A. caviae (14,80%), A. veronii biogrupo veronii (11,60%), Aeromonas sp. (7,36%), A. sobria (4,20%), A. trota (4,20%), A. schubertii (1,31%), A. jandaei (1,31%), A. veronii biogrupo sobria (0,52%) e Plesiomonas shigelloides (2,10%). A relevância epidemiológica desses microrganismos em casos de gastrenterite humana, após consumo de mexilhões crus ou parcialmente cozidos, revela a importância de alertar as autoridades de Saúde Pública no Brasil, sobre a presença desses patógenos na cadeia alimentar e seus riscos para a saúde humana.

Bactérias do gênero Aeromonas em abatedouro de frangos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo epidemiológico do gênero Aeromonas, por meio de técnicas moleculares, em diversas etapas do abate bovino

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aeromonas presence in drinking water from collective reservoirs and wells in peri-urban area in Brazil

Aeromonas genus is considered an emerging pathogen and its presence in drinking water supplies is a reason to public health concern. This study investigated the occurrence of Aeromonas in samples from collective reservoirs and wells used as drinking water sources in a peri-urban area. A total of 35 water samples were collected from collective reservoirs and 32 from wells bimonthly, from September 2007 to September 2008. Aeromonas spp determination was carried out using a Multiple-Tube Technique. Samples were inoculated into alkaline peptone water and the superficial film formed was transferred to blood agar plates amended with ampicillin. Typical Aeromonas colonies were submitted to a biochemical screening and then to biochemical tests for species differentiation. Aeromonas was detected in 13 (19%) of the 69 samples examined (6 from collective reservoirs and 7 from wells). Concentrations of Aeromonas in collective reservoirs ranged from <0.3 to 1.2 x10²MPN/100mL and, in wells, from <0.3 to 2.4 x10²MPN/100mL. The most frequent specie in the collective reservoir samples was Aeromonas spp (68%), followed by A. encheleia (14%) and A. allosaccharophila (8%) and A. hydrophila (8%). Aeromonas spp (87%) was the most frequent specie isolated from well samples, followed by A. allosacchariphila (8%), A. encheleia (2%) and A. jandaei (5%). These data show the presence and diversity of Aeromonas genus in the samples analyzed and highlight that its presence in drinking water poses a significant public health concern.

Aeromonas detection and their toxins from drinking water form reservoirs and drinking fountains

Aeromonads are inhabitants of aquatic ecosystems and are described as being involved in intestinal disturbances and other infections. A total of 200 drinking water samples from domestic and public reservoirs and drinking fountains located in São Paulo (Brazil), were analyzed for the presence of Aeromonas. Samples were concentrated by membrane filtration and enriched in APW. ADA medium was used for Aeromonas isolation and colonies were confirmed by biochemical characterization. Strains isolated were tested for hemolysin and toxin production. Aeromonas was detected in 12 samples (6.0%). Aeromonas strains (96) were isolated and identified as: A. caviae (41.7%), A. hydrophila (15.7%), A.allosacharophila (10.4%), A. schubertii (1.0%) and Aeromonas spp. (31.2%).The results revealed that 70% of A. caviae, 66.7% of A. hydrophila, 80% of A. allosacharophila and 46.6% of Aeromonas spp. were hemolytic. The assay for checking production of toxins showed that 17.5% of A. caviae, 73.3% of A. hydrophila, 60% of A. allosacharophila, 100% of A. schubertii, and 33.3% of Aeromonas spp. were able to produce toxins. The results demonstrated the pathogenic potential of Aeromonas, indicating that the presence of this emerging pathogen in water systems is a public health concern

Detection of metallo-'beta'-lactamases-encoding genes in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei

Aims: To determine the prevalence and expression of metallo-beta-lactamases (MBL)-encoding genes in Aeromonas species recovered from natural water reservoirs in southeastern Brazil. Methods and Results: Eighty-seven Aeromonas isolates belonging to Aeromonas hydrophila (n = 41) and Aer. jandaei (n = 46) species were tested for MBL production by the combined disk test using imipenem and meropenem disks as substrates and EDTA or thioglycolic acid as inhibitors. The presence of MBL genes was investigated by PCR and sequencing using new consensus primer pairs designed in this study. The cphA gene was found in 97.6% and 100% of Aer. hydrophila and Aer. jandaei isolates, respectively, whereas the acquired MBL genes bla(IMP), bla(VIM) and bla(SPM-1) were not detected. On the other hand, production of MBL activity was detectable in 87.8% and 10.9% of the cphA-positive Aer. hydrophila and Aer. jandaei isolates respectively. Conclusions: Our results indicate that cphA seems to be intrinsic in the environmental isolates of Aer. hydrophila and Aer. jandaei in southeastern Brazil, although, based on the combined disk test, not all of them are apparently able to express the enzymatic activity. Significance and Impact of the Study: These data confirm the presence of MBL-producing Aeromonas species in natural water reservoirs. Risk of water-borne diseases owing to domestic and industrial uses of freshwater should be re-examined from the increase of bacterial resistance point of view

Presence of 'BLA IND. TEM-116' gene in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei from Brazil

It is known that Aeromonas spp. possess different chromosomal beta-lactamase genes. Presence and phenotypic expression of bla(TEM), bla(SHV), and bla(CTX-M) ESBL-encoding genes were investigated in environmental water isolates of Aeromonas hydrophila and Aeromonas jandaei. Presence of blaSHV and blaCTX-M genes was not observed, and blaTEM gene was verified in 91% of the isolates. Sequencing of 10 fragments showed the occurrence of bla(TEM-116)

The identification of the transcriptional regulator CRP in Aeromonas hydrophila JMP636 and its involvement in amylase production and the 'acidic toxicity' effect

Aims: The physiological examination of amylase production by Aeromonas hydrophila JMP636 and identification of the mechanism of regulation. Methods and Results: Aeromonas hydrophila JMP636 was grown with single, then dual carbon sources; the growth cycle was followed and amylase activity throughout was monitored. The levels of cAMP, a known secondary messenger for the regulatory gene crp, were also examined. Amylase activity was regulated by catabolite repression. Physiological studies revealed that JMP636 exhibited both diauxic growth, with two carbon sources, and the 'acid toxicity' effect on glucose. The crp gene was cloned, expressed and inactivated from the JMP636 chromosome. Catabolite repression of amylase production and the 'acid toxicity' effect both require crp and were linked to cAMP levels. Conclusions: Regulation of amylase production was predicted to follow the model CRP-mediated cAMP-dependent Escherichia coli catabolite regulation system. Significance and Impact of the Study: This work provides an understanding of the physiology of the opportunistic pathogen Aer. hydrophila through identification of the mechanism of catabolite repression of amylase production and the existence of crp within this cell. It also provides a broader knowledge of global gene regulation and suggests regulatory mechanisms of other Aer. hydrophila gene/s.

Molecular characterization of Aeromonas spp. and Vibrio cholerae O1 isolated during a diarrhea outbreak

This work aimed to assess pathogenic potential and clonal relatedness of Aeromonas sp. and Vibrio cholerae isolates recovered during a diarrhea outbreak in Brazil. Clinical and environmental isolates were investigated for the presence of known pathogenic genes and clonal relatedness was assessed by intergenic spacer region (ISR) 16S-23S amplification. Four Aeromonas genes (lip, exu, gcat, flaA/B) were found at high overall frequency in both clinical and environmental isolates although the lip gene was specifically absent from selected species. A fifth gene, aerA, was rarely found in A. caviae, the most abundant species. The ISR profile revealed high heterogeneity among the Aeromonas isolates and no correlation with species identification. In contrast, in all the V. cholerae isolates the four genes investigated (ctxA, tcpA, zot and ace) were amplified and revealed homogeneous ISR and RAPD profiles. Although Aeromonas isolates were the major enteric pathogen recovered, their ISR profiles are not compatible with a unique cause for the diarrhea events, while the clonal relationship clearly implicates V. cholerae in those cases from which it was isolated. These results reinforce the need for a better definition of the role of aeromonads in diarrhea and whether they benefit from co-infection with V. cholerae.

DIARRHEA OUTBREAK IN PERNAMBUCO, BRAZIL, ASSOCIATED WITH A HEAT-STABLE CYTOTOXIC ENTEROTOXIN PRODUCED BY Aeromonas caviae

SUMMARY In the present study enterotoxic and cytotoxic activities of twenty Aeromonas caviaestrains were examined. They originated from fecal specimens of patients with acute diarrhea during an outbreak in Brazil in 2004. Culture supernatants of fourteen strains (70%) caused fluid accumulation in rabbit ileal intestinal loops and in suckling mice assays, and also showed a cytotoxic activity in Vero and Caco-2 cells. The enterotoxic and cytotoxic factors were heat-stable after culture supernatants treatment at 100 ºC. The results revealed that A. caviaestrains produce a putative diarrheagenic virulence factor, a heat-stable cytotoxic enterotoxin that could be linked to the diarrhea outbreak that took place in Brazil.

Prevalência de Aeromonas ssp em fezes diarréicas de crianças menores de 5 anos de idade na cidade de Goiânia, Goiás, no biênio 1995 - 1996

Foram analisadas 163 amostras de fezes de crianças com idade abaixo de 5 anos no período de 1995 a 1996, sendo 91 de fezes diarréicas e 72 de fezes não diarréicas. O material foi coletado em meio para transporte e submetido ao processo de enriquecimento a 4oC por 7 dias. Para o isolamento primário foi utilizado ágar amido ampicilina e incubado a 35oC por 18 a 24 horas. Foram isoladas 20 (21,9%) das seguintes espécies: Aeromonas A. caviae (7,7%), A. salmonicida salmonicida (6,6%), A. sobria (4,3%), A. hydrophila (2,2%) e Salmonicida achromogenes (1,1%). Nenhuma Aeromonas spp foi isolada dos 72 pacientes-controles. A susceptibilidade das amostras de Aeromonas spp aos antimicrobianos foi maior com a ciprofloxacina, diminuindo gradativamente com cloranfenicol, gentamicina, ampicilina e eritromicina.