Genomics of the Argentinian cholera epidemic elucidate the contrasting dynamics of epidemic and endemic Vibrio cholerae.

In order to control and eradicate epidemic cholera, we need to understand how epidemics begin, how they spread, and how they decline and eventually end. This requires extensive sampling of epidemic disease over time, alongside the background of endemic disease that may exist concurrently with the epidemic. The unique circumstances surrounding the Argentinian cholera epidemic of 1992-1998 presented an opportunity to do this. Here, we use 490 Argentinian V. cholerae genome sequences to characterise the variation within, and between, epidemic and endemic V. cholerae. We show that, during the 1992-1998 cholera epidemic, the invariant epidemic clone co-existed alongside highly diverse members of the Vibrio cholerae species in Argentina, and we contrast the clonality of epidemic V. cholerae with the background diversity of local endemic bacteria. Our findings refine and add nuance to our genomic definitions of epidemic and endemic cholera, and are of direct relevance to controlling current and future cholera epidemics.

Isolation of Salmonella spp. from yacare caiman (Caiman yacare) and broad-snouted caiman (Caiman latirostris) from the Argentine Chaco.

Presence of Salmonella spp. was evaluated in yacare caiman (Caiman yacare) and broad-snouted caiman (Caiman latirostris) from a ranching facility in the Argentine Chaco. Crocodilian ranching programs are based on captive breeding of wild-harvested eggs and release of excess hatchlings into the wild. Samples for bacterial isolation were collected from 102 captive (35 C. yacare and 67 C. latirostris) and seven free-ranging caiman (four C. yacare and three C. latirositris) between 2001 and 2005 and from three artificially incubated C. yacare wild eggs. Two Salmonella spp. of known zoonotic potential, S. infantis and S. nottingham, were isolated from captive caiman in 2001 and 2002, respectively. This is the first report for S. nottingham in reptiles and of S. infantis in caiman. Salmonella spp. prevalence varied significantly between years, with a 77% prevalence peak in 2002. Although the cause of this increase was not confirmed, we found no correlation with the type of enclosure, caiman species, or body weight. Deteriorated physical condition of caiman hatchlings due to dietary changes in 2002 could have influenced Salmonella spp. shedding. However, external sources such as food, water, or enclosures could not be ruled out. Pathogenic Salmonella spp. present a risk for human infection. Inadvertent introduction of Salmonella spp. or other bacteria into the environment when caiman are released could pose a threat to wild caiman populations. Prophylactic measures to detect and decrease Salmonella spp. presence in caiman ranching facilities are recommended to reduce risk to humans and make caiman-ranching a sound conservation strategy for crocodilian species.

Salmonelosis extraintestinal: clínica, epidemiología y resistencia antimicrobiana / Salmonella extraintestinal infection: clinic features, epidemiology and antimicrobial resistance

Se evaluaron retrospectivamente las características clínicas de 59 pacientes con aislamientos extraintestinales de Salmonella enterica no Typhi y la resistencia antibiótica entre 1988 y 2004. En el 95% de los casos se conocieron las condiciones de base del huésped que consistieron en: enfermedad oncohematológica (15), lupus eritematoso sistémico (11), síndrome de inmuno deficiencia adquirida (10), pacientes internados en neonatología (8), colecistitis (4) y otras (7). Las formas clínicas halladas fueron: bacteriemias primarias (26), bacteriemias secundarias a gastroenteritis (15), artritis séptica (7), infección urinaria (12), infección intraabdominal (5), meningitis (1) y pericarditis (1). En 29 pacientes se aisló Salmonella enterica no Typhi en más de una localización. El 15,8% y el 21,0% de 59 aislamientos presentaron resistencia a cefalosporinas de 3ª generación y a ampicilina, respectivamente. Salmonella Agona causó un brote epidémico en la sala de cuidados intensivos de neonatología, aislándose de sangre en 5 pacientes y en uno también de LCR. Este serotipo fue multirresistente. Imipenem, trimetroprima-sulfometoxazol y ciprofloxacina fueron los antibióticos más activos (CIM 50: 0,5; 0,5 y 0,002 µg/mL, respectivamente).

The clinical and antimicrobial resistance of 59 patients with extraintestinal infection by nontyphi Salmonella was retrospectively evaluated from 1988 to 2004. In 95% of the patients there were underlying diseases, which included: oncohematologic disease (15), systemic lupus erythematosus (11), acquired immunodeficiency disease (AIDS) (10), patients of neonatal units (8), colecistitis (4), and other disorders (7). The clinical manifestation were primary bacteremias (26), bacteremias secondary to gastroenteritis (15), arthritis (7), urinary tract infections (12), abdominal infections (5), meningitis (1) and pericarditis (1). In 29 patients Salmonella enterica no Typhi was isolated in more than one site. Resistance to third generation cephalosporins was observed in 15,8 % of these isolates, and resistance to ampicillin in 21,0%. Salmonella Agona was isolated from an outbreak in neonatal ICU; the organism was recovered from blood samples of five neonates and in one patient also isolated from CSF. These isolates showed multiresistance. Imipenem, trimetoprim-sulfametoxazol and ciprofloxacin were the three most active antimicrobial agents (MIC 50: 0.5, 0.5 and 0.002 µg/mL, respectively).

Importancia de la Salmonella enteritidis en brotes de enfermedades transmitidas por alimentos en Argentina, años 1986 - 1988 / Significance of Salmonella enteritidis in outbreaks of diseases transmitted by foods in Argentina, 1986 - 1988

La presente comunicación informa los brotes de enfermedades transmitidas por alimentos producidos por Salmonella Enteritidis, que ocurrieron en la Argentina entre 1986 y 1988. Del total de 39 episodios registrados, se estudiaron 210 cepas aisladas de heces humanas (28 brotes) y 59 de alimentos (23 brotes). Fueron afectadas más de 2.500 personas en distintas provincias, caracterizándose el cuadro clínicos por la gravedad de los síntomas (fiebre, vómitos, diarreas y gran deshidratación). La principal fuente de infección se relacionó con huevos crudos, consumidos en forma de mayonesa artesanal. Se consdiera necesario realizar un efectivo control de los productos aviarios, así como una permanente vigilancia de la salmonellosis

Serovariedades de Salmonella em águas superficiais em San Luís, Argentina / Salmonella serotypes from surface waters in San Luis, Argentina

Resumo: Foi investigada a presença de Smonella em amostras de água colhidas pela técnica de Moore, em rios e açudes, durante um ano. Realizau-se um pré-enriquecimento em água peptomada tamponada e um enriquecimento em caldo tetrationato-verde brilhante com caldo Rappaport. Isolou-se em 0gar verde brilhantre com desoxicolato de sódio a 0,25 (por cento) e em ágar sulfito de bismuto. As colônias suspeitas foram estrudadas mediante provas bioqu1micas clássicas e sorológicas. Recuperou-se Salmonella em 6,66 (por cento) das amostras. Isolou-se S. panama, S. newport, S. sandiego e Salmonella sub-espécie IV, 40: Z4, Z23: esta última serovariedade constitui o primeiro isolamento na Argentina. Determinou-se o antibiograma pelo método de Kirby-Bauer. As 15 cepas isoladas foram sensíveis a trimetroprima-sulfametoxazol, gentamicina, tetraciclina, cloranfenicol, kamamicina e ácido nalidíxico, quanto à carbenicilina, 6 cepas foram resistentes, 7 mostraram sensibilidade intermediária e só 2 foram sensíveis. -Foram determinados perfis plasmídicos pela técnica de Birnboin e dOLY. Os pesos moleculares (PM) dos plasmídeos em megadaltons (MDa) foram determinados por comparaçäo com plasmídeos de PM conhecidos. Foram detectados plasmídeos de PM 40 MDa em S. newpot e de PM 17 MDa em S. sandiego. Seria de interesse a determinaçäo sistemática de marcadores epidemiológicos em surtos e casos esporádicos de salmonelose com o fim de estabelecer sua distribuiçäo geográfica na zona estudada da província de San Luis, assim como também a necessidade de uma vigilância microbiológica das águas superficiais e a implementaçäo de tratamentos de depuraçäo de águas cloacais adequadois antes de serem despejadas nos cursos de água (au)