Rosane Salete Friedrich

Aeromonas Hydrophila Isolated from Cases of Bovine Seminal Vesiculitis in South Brazil

Preliminary studies on pathologic conditions in the testis, epididymis, and the accessory sex glands of cattle have demonstrated that vesiculitis is the most common inflammatory condition in the genitals of Danish bulls.5 Occasionally, this condition has an acute onset that produces clinical signs and then becomes a chronic disease.18 Four-polled Hereford bulls approximatedly 1 year of age (1–2 years old) from a farm in southern Brazil were examined by rectal palpation. During this procedure, enlargement of the seminal vesicles was detected. The animals were slaughtered, and samples were collected for bacteriologic and histopathologic examination. Macroscopically, the seminal vesicles were enlarged and firm and contained foci of yellow exudate. The histopathologic examination revealed interstitial seminal vesiculitis with areas of lymphocytic and plasma cell infiltration surrounding alveoli containing suppurative exudate. Varying degrees of fibrosis were found in the glands. Samples of a selected group of organs were available for sectioning. For bacteriologic examination, fragments of seminal vesicles were inoculated asseptically onto 5% (w/v) sheep blood agar and incubated aerobically at 37 C for 24–48 hours. Microorganisms from all seminal vesicles were isolated in pure culture. The colonies were beta-hemolytic, smooth, small, and white and had characteristics of the genus Aeromonas (gram-negative rods, oxidase positive, fermentative metabolism, and resistant to vibriostatic agent 2,4,diamino6,7-diisopropylpteridine, O/129, 150 mg). According to the biochemical profile the Aeromonas isolates were classified as Aeromonas hydrophila (Table 1).14 There have been no previous reports of seminal vesiculitis in bulls associated with Aeromonas spp. However, in a previous report of the isolation of A. hydrophila from feces of healthy cattle, this species was suggested as an occasional host to Aeromonas.1 Aeromonas hydrophila isolated from the genital tract of cows was associated with abortion.28 Nonetheless, bovine seminal vesiculitis associated with other microrganisms such as Actinomyces pyogenes,4,5,8 Escherichia coli,3 Brucella abortus,24 Mycoplasma bovigenitalium,2,13 Haemophilus somnus,12 and Pseudomonas aeruginosa4 have also been described. Although, some authors consider it unlikely that any bac-

Antimicrobial action of root canal filling pastes used in deciduous teeth

Purpose: This study assessed the antimicrobial effectiveness of an iodoform-based paste (Guedes-Pinto Paste, GPP) and a paste modified by the addition of a 2% chlorhexidine gluconate gel (CHX) to replace the camphorated parachlorophenol component of the original GPP. Methods: The antimicrobial action was tested against the following microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus oralis, Enterococcus faecalis, Escherichia coli and Bacillus subtilis. In the agar diffusion test, 18 Petri plates with 20 mL of BHIA were inoculated with 0.1 mL of the microbial suspensions. Paper disks were immersed in the experimental solutions for 1 min and were then placed over the BHIA surface in each agar plate. The plates were maintained for 1 h at room temperature and then incubated at 37oC for 48 h. The diameters of the microbial inhibition halos were measured around the paper disks containing the substances. Data were analyzed using the Mann-Whitney U-test (α=0.05). Results: Antimicrobial action was observed for the GPP and CHX pastes, which presented absence of turbidity for almost all microorganisms. No statistically significant difference in the antimicrobial action was found between GPP and CHX. Conclusion: Both pastes present similar antimicrobial effectiveness against several microorganisms commonly found in endodontic infections in deciduous teeth.

Bacteriocin-like substance of Aeromonas hydrophila.

The genus Aeromonas comprises Gram negative rods found mainly in aquatical environments that may infect humans and animals (JM Janda 1991 Clin Microbiol Rev 4: 397-410). In humans, some Aeromonas species have been associated with intestinal and extraintestinal infections and enterotoxins, cytotoxins as well as invasive mechanisms have been incriminated in the development of illness in the host (Janda loc. cit.). Bacteriocin-like substances (BLS) are protein compounds produced by some bacteria (G Ivanovics 1962 Bacteriol Rev 26: 108-118) showing antagonic activity against their own species (isoinhibitory activity IA) or other non-related species (heteroinhibitory activity HA). The use of the expression BLS is recommended to nominate bacterial products showing antagonic activity though not characterized (K Sandhu et al. 1983 J Clin Microbiol 17: 511-515). These substances have been widespread utilized in epidemiological studies as specific marker properties of bacteria, in the regulation of population dynamics in bacterial ecosystems and clinical treatment (V Fantinato & F Zelante 1991 Rev Microbiol 22: 49-51). As BLS have not been currently described in Aeromonas species, the purpose of this study was to investigate their production in strains isolated from animal, clinical and environmental sources. The assays for the production of BLS were performed according to Sandhu et al. (loc. cit.). The strains used as BLS producers and BLS indicators are listed in Table. Our results showed that among 32 Aeromonas strains, the BLS could be only demonstrated in a strain of A. hydrophila isolated from a water tank containing alligators. This strain demonstrated heteroinhibitory activity against four Staphylococcus aureus strains (one ATCC 6538 and three methicillin-resistant MRSA). The heteroinhibitory activity was demonstrated after an incubation of 48 hr at 37°C and not at 25°C, conditions also observed for the BLS production in Serratia, Pseudomonas, Leuconostoc and Enterococcus strains (JD Foulds & D Shemin 1969 J Bacteriol 99: 655-660, JRW Govan & G Harris 1985 J Clin Microbiol 22: 490-494, F Mathleu et al. 1993 J Appl Bacteriol 74: 372-379, F Villani 1993 J Appl Bacteriol 74: 380-387). The heteroinhibitory activity was demonstrated by inhibitory zones ranging from 17 to 27mm. JR Govan (1986 Scand J Infec Dis 49: 31-37) proposed that different inhibition zone diameters may depend on the potency either of BLS action or they may be correlated with the number of receptors for BLS in the bacterial surface. In spite of these results, further research is necessary to better understand the bacteriocin-like activity in Aeromonas species as well as to investigate the chemical nature of this substance and its pharmacological usefulness.