Recommendation of an Appropriate Medium for In Vitro Drug Susceptibility Testing of the Fish Pathogen
            <i>Tenacibaculum maritimum</i>

Avendaño‐Herrera, Rubén; Irgang, Rute; Núñez, Soledad; Romalde, Jesús L.; Toranzo, Alicia E.

doi:10.1128/aac.49.1.82-87.2005

Cited by 15 publications

(15 citation statements)

References 30 publications

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“…The MIC was determined using the broth microdilution testing method as described in NCCLS standard M31-A2 (2002), with some modification in the medium composition, incubation time, and temperature as required for T. maritimum (Avendaño-Herrera et al 2005). One hundred strains of T. maritimum were evaluated in duplicate (Table 1).…”

Section: Estimation Of Enrofloxacin Micmentioning

confidence: 99%

“…Antimicrobial susceptibility testing Sensitivity to antimicrobial agents was evaluated by disk diffusion susceptibility testing on FMM plates, which was prepared using seawater as diluent according to the original descriptions (Pazos et al 1996), and due to the known strict halophilic nature of this bacterium (Avendaño-Herrera et al 2005). Eight chemotherapeutic agents used for the treatment of bacterial diseases in fish were selected.…”

Section: Bacterial Isolatesmentioning

confidence: 99%

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Evolution of drug resistance and minimum inhibitory concentration to enrofloxacin in Tenacibaculum maritimum strains isolated in fish farms

et al. 2007

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The in vitro susceptibility of 63 isolates of Tenacibaculum maritimum from four fish farms to eight chemotherapeutic agents used for the treatment of bacterial diseases in fish were assessed. The results indicated that all strains were resistant to oxolinic acid and susceptible to amoxicillin, nitrofurantoin, florfenicol, oxytetracycline and trimethoprim-sulphamethoxazole. However, some isolates presented resistance to enrofloxacin and flumequine, ranging from 10 to 30%, and from 25 to 60%, respectively, depending on the farm sampled. These data were used in an attempt to predict whether the resistance to enrofloxacin was static or evolved during the time of sampling from 2003 to 2004. A relationship between the use of enrofloxacin and levels of resistance was detected in the studied farm, increasing significantly from no resistant isolates in 2003 to 44.8% resistant strains in 2004, the year in which this drug was commonly employed. This result was accompanied by a marked decline of about 29.2% of the inhibition zone sizes for the T. maritimum strains in comparison to the initial values (average 21.5 mm). Minimum inhibitory concentration (MIC) of enrofloxacin for 100 T. maritimum strains was determined by the microdilution method. Twenty isolates were resistant to enrofloxacin (> 256 mg ml À1 ), while the remaining strains showed a bimodal distribution, which ranged from 0.5 to 32 mg ml À1 . Our interpretation of the enrofloxacin MIC data suggests that the breakpoint for T. maritimum should be 4 mg ml À1 . However, similar studies in other laboratories are necessary to validate this breakpoint value.

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Section: Estimation Of Enrofloxacin Micmentioning

confidence: 99%

Section: Bacterial Isolatesmentioning

confidence: 99%

Evolution of drug resistance and minimum inhibitory concentration to enrofloxacin in Tenacibaculum maritimum strains isolated in fish farms

et al. 2007

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“…The ability of the T. maritimum strains to grow in the presence of the nonassimilable iron chelator ethylenediamine-di-(o-hydroxyphenyl-acetic acid) (EDDHA; Sigma) was determined by using FMM broth as a basal medium due to the known strict halophilic nature of this bacterium (7). MICs were obtained by adding increasing concentrations of EDDHA and were defined as the lowest concentration at which no bacterial growth was observed.…”

Section: Methodsmentioning

confidence: 99%

Iron Uptake Mechanisms in the Fish Pathogen Tenacibaculum maritimum

Avendaño‐Herrera

Toranzo

Romalde

et al. 2005

Appl Environ Microbiol

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We present here the first evidence of the presence of iron uptake mechanisms in the bacterial fish pathogen Tenacibaculum maritimum. Representative strains of this species, with different serotypes and origins, were examined. All of them were able to grow in the presence of the chelating agent ethylenediamine-di-(o-hydroxyphenyl acetic acid) (EDDHA) and also produced siderophores. Cross-feeding assays suggest that the siderophores produced are closely related. In addition, all T. maritimum strains utilized transferrin, hemin, hemoglobin, and ferric ammonic citrate as iron sources when added to iron-deficient media. Whole cells of all T. maritimum strains, grown under iron-supplemented or iron-restricted conditions, were able to bind hemin, indicating the existence of constitutive binding components located at the T. maritimum cell surface. This was confirmed by the observation that isolated total and outer membrane proteins from all of the strains, regardless of the iron levels of the media, were able to bind hemin, with the outer membranes showing the strongest binding. proteinase K treatment of whole cells did not affect the hemin binding, indicating that, in addition to proteins, some protease-resistant components could also bind hemin. At least three outer membrane proteins were induced in iron-limiting conditions, and all strains, regardless of their serotype, showed a similar pattern of induced proteins. The results of the present study suggest that T. maritimum possesses at least two different systems of iron acquisition: one involving the synthesis of siderophores and another that allows the utilization of heme groups as iron sources by direct binding. Tenacibaculum maritimum (formerly Flexibacter maritimus)(48) is the etiological agent of an ulcerative disease known as marine flexibacteriosis or tenacibaculosis, which affects a large number of marine fish in the world and thus has considerable economic significance to aquaculture producers. The infection has diverse clinical manifestations depending on the species and age of fish, the most significant symptom being the presence of gross lesions on the body surface (11,16).Although the phenotypic, antigenic, and molecular characteristics of T. maritimum have been examined by several authors (for a review, see reference 49), the actual factors determining the virulence of this pathogen have not yet been elucidated. Some synergistic interactions of the toxins contained in extracellular products and a hemolysin might be involved in T. maritimum infections (8). Moreover, pathological properties of the bacterium, such as a strong adherence to the skin mucus of different fish species and the capacity to resist its bactericidal activity (31), have been pointed out as possible virulence factors.It is well known that the ability to take up iron during infection is an essential factor in the pathogenicity of several bacteria, being necessary for the pathogen multiplication. However, the levels of free iron in the biological fluids within the animal host is often v...

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“…In vitro studies on the susceptibility of Tenacibaculum maritimum to various chemotherapeutic agents indicate that bacterial strains isolated from different host species and geographical regions exhibit a similar pattern, with respect to susceptibility to nitrofurans, penicillins, erythromycin, tetracyclines, chloramphenicol, trimethoprim, potentiated sulfonamides and fluoroquinolones, and resistance to colistin, kanamicyn, neomicyn and the quinolones, oxolinic acid and flumequine (Baxa et al 1988c, Alsina & Blanch 1993, Pazos et al 1993, Chen et al 1995, Soltani et al 1995, Avendaño-Herrera et al 2004b, 2005a. However, field results were not always similar even if the isolated bacteria were highly sensitive (in vitro) to the drug used for treating the condition (Cepeda & Santos 2002).…”

Section: Treatment and Prevention Of Tenacibaculosis Chemotherapymentioning

confidence: 99%

“…T. maritimum seems to grow better on this medium in comparison to heterotrophic halophilic bacteria such as Vibrio, Pseudomonas and Alteromonas spp., which are usually present in skin samples. This medium, as well as FMM prepared with commercial sea salts instead of seawater, has also been recommended for use in the routine drug susceptibility testing of this demanding pathogen (Avendaño-Herrera et al 2005a). The incubation on most media is usually carried out at 20 to 25°C for 48 to 72 h. In addition, it is important to note that only on FMM and AOA do the colonies exhibit the typical features described for this species -flat, pale-yellow with uneven edges and strongly adherent to the mediumwhereas on marine agar, colonies are round and show yellow pigment (Pazos et al 1996).…”

Section: Isolation and Phenotypic Characterizationmentioning

confidence: 99%

Tenacibaculosis infection in marine fish caused by Tenacibaculum maritimum: a review

2006

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Tenacibaculum maritimum is the aetiological agent of an ulcerative disease known as tenacibaculosis, which affects a large number of marine fish species in the world and is of considerable economic significance to aquaculture producers. Problems associated with epizootics include high mortality rates, increased susceptibility to other pathogens, high labour costs of treatment and enormous expenditures on chemotherapy. In the present article we review current knowledge on this bacterial pathogen, focusing on important aspects such as the phenotypic, serologic and genetic characterization of the bacterium, its geographical distribution and the host species affected. The epizootiology of the disease, the routes of transmission and the putative reservoirs of T. maritimum are also discussed. We include a summary of molecular diagnostic procedures, the current status of prevention and control strategies, the main virulence mechanisms of the pathogen, and we attempt to highlight fruitful areas for continued research. TAXONOMYThe taxonomy of Tenacibaculum maritimum was a matter of controversy and confusion for decades, and it has only recently been clarified by Suzuki et al. (2001). Masumura & Wakabayashi (1977) isolated a gliding bacterium that had caused mass mortalities among certain cultured marine fish. These strains were characterized by Hikida et al. (1979), who announced their intention to make a separate formal proposal of the name Flexibacter marinus. Since the epithet marinus had already been used in the name Vibrio marinus, the authors changed their mind on the use of this epithet, and the eventual formal proposal was a taxon called Flexibacter maritimus (Wakabayashi et al. 1986, Holmes 1992. Reichenbach (1989) listed the pathogen as Cytophaga marina, but the priority of the name Flexibacter maritimus was later recognized (Holmes 1992). These results were confirmed by Bernardet & Grimont (1989), who also validated the name Flexibacter maritimus based on DNA-DNA hybridisation methods.However, the resolution of phenotypic characterization and 16S ribosomal RNA (rRNA) sequence analysis is insufficient to distinguish closely related organisms. Thus, Suzuki et al. (2001), based on the nucleotide sequence of the gyrB, proposed that Flexibacter maritimus should be transferred to the new genus Tenacibaculum, in which 7 members are currently included. Table 1 shows the main differential characteristics of the described species of the genus Tenacibaculum. GEOGRAPHICAL DISTRIBUTION AND HOST SPECIESThe geographical distribution of Tenacibaculum maritimum in wild and farmed fish is shown in Table 2. 256 Characteristic T. maritimum T. ovolyticum T. mesophilum T. amilotyticum T. skagerrakense T. lutimarisOrigin Diseased red sea Halibut egg, Sponge and Macroalgae, Pelagic, Tidal flat, bream fingerling, Japan Norway macroalgae, Japan Japan Denmark Korea Cells size (µm) 2-30 × 0.5 2-20 × 0.5 1.5-10 × 0.5 2-4 × 0.4 2-15 × 0.5 2-10 × 0. Percentage of NaCl in the medium Table 1. Differential phenotypic characteris...

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Recommendation of an Appropriate Medium for In Vitro Drug Susceptibility Testing of the Fish Pathogen Tenacibaculum maritimum

Cited by 15 publications

References 30 publications

Evolution of drug resistance and minimum inhibitory concentration to enrofloxacin in Tenacibaculum maritimum strains isolated in fish farms

Evolution of drug resistance and minimum inhibitory concentration to enrofloxacin in Tenacibaculum maritimum strains isolated in fish farms

Iron Uptake Mechanisms in the Fish Pathogen Tenacibaculum maritimum

Tenacibaculosis infection in marine fish caused by Tenacibaculum maritimum: a review

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