The vehicle used to prepare the calcium hydroxide paste might contribute to its antibacterial action. Chlorhexidine gluconate gel used alone, and camphorated p-monochlorophenol and camphorated p-monochlorophenol-propylene glycol as vehicles of calcium hydroxide, could be recommended, in an antimicrobial sense.

No abstract

Aims:  To determine the presence of Vibrio cholerae in different areas of Argentina in three sample types, to determine the composition of planktonic communities in areas at which this pathogen was detected and to characterize the virulence properties and antimicrobial resistance of the recovered environmental isolates. Methods and Results:  Water and plankton samples were collected in marine, brackish and freshwater environments. Vibrio cholerae non‐O1, non‐O139 was isolated in 36·1% of the samples analysed. The micro‐organism was detected in freshwater but not in marine or brackish samples. No relationship was found between isolation of V. cholerae and presence of any species of plankton. All the isolates presented very similar virulence profiles by PCR, lacking ctxA and tcpA El Tor and containing hlyA (98·7%), rtxA (99·0%), toxR (98·7%) and stn‐sto (1·9%). Resistance to ampicillin was found in both Tucumán (21%) and Buenos Aires isolates (45%). Conclusions:  We identified two geographic areas in Argentina where V. cholerae was present: freshwaters of the rivers from Tucumán and the Río de la Plata. Significance and Impact of the Study:  The identification of V. cholerae strains in the environment, carrying both virulence factors and resistance to antimicrobial agents, highlight the need for a continuous and active surveillance of this pathogen.

RESUMEN.Vibrio cholerae reside habitualmente en aguas marinas y continentales. Según las condiciones ambientales y los recursos le sean "favorables" o "desfavorables", se generan estados viables cultivables (VC) o viables no cultivables (VNC) respectivamente y, bajo esta última forma sobrevive. Para abordar la problemática del cólera en la Cuenca del Río Salí (Tucumán, Argentina), se realizaron muestreos durante los años 2003-2005 donde se consideraron aspectos fisicos, químicos, biológicos y sanitarios. Para evaluar los probables reservorios del patógeno, se analizó el zooplancton del Río Salí (Canal Norte y Banda Río Salí) y Río Lules. La mayor representatividad taxonómica la registraron los copépodos, especialmente Eucyclops neumani (Pesta, 1927), junto a Acanthocyclops robustus (Sars, 1863), Metacyclops sp., Paracyclops chiltoni y Notodiaptomus incompositus (Brian, 1925), además de algunos rotíferos y cladóceros como (Lecane sp.), y (Brachionus sp., Moina sp. y Leydigia sp.). La frecuencia de ocurrencia fue baja y no superó el 25%. El Canal Norte fue ambiente más propicio por la riqueza específica, abundancia y constancia de la comunidad. Las variables fisicas y químicas asociadas al zooplancton coincidirían con los valores que por nuestros registros y los antecedentes, se conocen para el desarrollo del patógeno. En el período estival hubo coincidencia entre la presencia de la forma VNC de V. cholerae O1 (inmunofluorescencia con anticuerpos anti O1) y el desarrollo del zooplancton. Se observaron formas VNC sobre apéndices o estructuras de copépodos ciclopoideos y cladóceros quidóridos, reflejando probablemente afinidad con sustratos quitinosos.

Ampicillin was selected to further study the effect of this antibiotic on the colonization capability of S. pneumoniae and L. fermentum intranasally inoculated in a mice experimental model. The sensitivity of S. pneumoniae and L. fermentum to antibiotics was evaluated by different "in vitro" techniques. The results showed that both microorganisms have a typical pattern of sensitivity to antibiotics in these assays. The "in vivo" experiments showed that the treatment with Ampicillin increased the number of lactobacilli and neumococci in the groups of mice treated only with one of the microorganisms. In those mice treated with Lactobacillus, challenged later with neumococci and treated with Ampicillin, the pathogen in lung decreased on the 4th day, disappearing completely after on. The histological studies showed that the antibiotic treatment decreased the inflammatory response produced by the pathogen at the lung and trachea levels.