Detecting residual chronic Salmonella Typhi carriers on the road to typhoid elimination in Santiago, Chile, 2017-2019.

OBJECTIVES: In Santiago, Chile, where typhoid had been hyperendemic (1977-1991), we investigated whether residual chronic carriers could be detected among household contacts of non-travel-related typhoid cases occurring 2017-2019. METHODS: Culture-confirmed cases were classified as "autochthonous" (domestically-acquired) versus "travel/immigration-related". Household contacts of cases had stool cultures and serum Vi antibody measurements to detect chronic Salmonella Typhi carriers. Whole genome sequences of acute cases and their epidemiologically-linked chronic carrier isolates were compared. RESULTS: Five of 16 autochthonous typhoid cases (31.3%) were linked to four chronic carriers in case households; two cases (onsets 23 months apart) were linked to the same carrier. Carriers were women aged 69-79 years with gallbladder dysfunction and Typhi fecal excretion; three had highly elevated serum anti-Vi titers. Genomic analyses revealed close identity (≤11 core genome SNP [Single Nucleotide Polymorphism] differences) between case and epidemiologically-linked carrier isolates; all were genotypes prevalent in 1980s Santiago. A cluster of four additional autochthonous cases un-linked to a carrier was identified based on genomic identity (0-1 SNPs). Travel/immigration isolate genotypes were typical for the countries of travel/immigration. CONCLUSIONS: Although autochthonous typhoid cases in Santiago are currently rare, 5/16 such cases (31.3%) were linked to elderly chronic carriers identified among household contacts of cases.

Whole genome sequence analysis of Salmonella Typhi provides evidence of phylogenetic linkage between cases of typhoid fever in Santiago, Chile in the 1980s and 2010-2016.

Typhoid fever epidemiology was investigated rigorously in Santiago, Chile during the 1980s, when Salmonella enterica serovar Typhi (S. Typhi) caused seasonal, hyperendemic disease. Targeted interventions reduced the annual typhoid incidence rates from 128-220 cases/105 population occurring between 1977-1984 to <8 cases/105 from 1992 onwards. As such, Santiago represents a contemporary example of the epidemiologic transition of an industrialized city from amplified hyperendemic typhoid fever to a period when typhoid is no longer endemic. We used whole genome sequencing (WGS) and phylogenetic analysis to compare the genotypes of S. Typhi cultured from acute cases of typhoid fever occurring in Santiago during the hyperendemic period of the 1980s (n = 74) versus the nonendemic 2010s (n = 80) when typhoid fever was rare. The genotype distribution between "historical" (1980s) isolates and "modern" (2011-2016) isolates was similar, with genotypes 3.5 and 2 comprising the majority of isolations, and 73/80 (91.3%) of modern isolates matching a genotype detected in the 1980s. Additionally, phylogenomically 'ancient' genotypes 1.1 and 1.2.1, uncommon in the global collections, were also detected in both eras, with a notable rise amongst the modern isolates. Thus, genotypes of S. Typhi causing acute illness in the modern nonendemic era match the genotypes circulating during the hyperendemic 1980s. The persistence of historical genotypes may be explained by chronic typhoid carriers originally infected during or before the 1980s.

Multiple Introductions of Salmonella enterica Serovar Typhi H58 with Reduced Fluoroquinolone Susceptibility into Chile.

Salmonella enterica serovar Typhi H58, an antimicrobial-resistant lineage, is globally disseminated but has not been reported in Latin America. Genomic analysis revealed 3 independent introductions of Salmonella Typhi H58 with reduced fluoroquinolone susceptibility into Chile. Our findings highlight the utility of enhanced genomic surveillance for typhoid fever in this region.

[Salmonella spp. gastroenteritis associated to pet turtles in three infants]. / Gastroenteritis por Salmonella spp. en tres lactantes asociada a contacto con tortugas acuáticas.

Non-typhoidal salmonellosis is an important cause of acute diarrhea in children. Generally they are acquired by consumption of contaminated food, but contact with reptiles is an increasing cause of this zoonoses. We describe three pediatric cases of gastroenteritis by Salmonella (Montevideo, Newport and Pomona), related to having turtles as pets. In two cases, the bacteria were isolated from the patient's stools and the turtle's droppings. The same genetic subtype by PFGE was obtained in both isolates. All the children recovered. Information and public health measures should be undertaken to control this zoonoses which affects young children.

Gastroenteritis por Salmonella spp. en tres lactantes asociada a contacto con tortugas acuáticas / Salmonella spp. gastroenteritis associated to pet turtles in three infants

Non-typhoidal salmonellosis is an important cause of acute diarrhea in children. Generally they are acquired by consumption of contaminated food, but contact with reptiles is an increasing cause of this zoonoses. We describe three pediatric cases of gastroenteritis by Salmonella (Montevideo, Newport and Pomona), related to having turtles as pets. In two cases, the bacteria were isolated from the patient’s stools and the turtle’s droppings. The same genetic subtype by PFGE was obtained in both isolates. All the children recovered. Information and public health measures should be undertaken to control this zoonoses which affects young children.

Las infecciones por Salmonella no tíficas, son una importante causa de diarrea aguda en niños. Generalmente adquiridas por alimentos contaminados, el contacto con animales, especialmente reptiles, también es responsable de esta zoonosis. Describimos tres casos de lactantes con gastroenteritis por Salmonella (S. Montevideo, S. Newport y S. Pomona), relacionados a contacto con tortugas mascotas. En dos de los casos se aisló Salmonella en las deposiciones de los niños y de las tortugas. En todos hubo proximidad entre los niños y los acuarios y/o tortugas, siendo probable la contaminación en la preparación de alimentos. El estudio de clonalidad por electroforesis de campo pulsado demostró el mismo subtipo genético en el aislado correspondiente al paciente y en el procedente de la mascota, lo cual confirmó la fuente zoonótica de los casos. Esta zoonosis debe ser abordada por las autoridades de salud y las sociedades científicas, ya que representa un importante riesgo para la salud, especialmente de niños pequeños.

Identification of diverse Salmonella serotypes, virulotypes, and antimicrobial resistance phenotypes in waterfowl from Chile.

Salmonella enterica is a pathogen with a wide host-range that presents great concern in developed and developing countries. To determine and characterize Salmonella strains found in Chile's waterfowl, we sampled 758 birds along 2000 km of the Chilean coast. In this sample, 46 isolates from 10 serotypes were detected, several with multidrug resistance phenotypes and different combinations of virulence-associated genes (virulotypes). These results suggest that Salmonella infection in waterfowl in Chile could have impacts on public and animal health.

[Report of four clinical cases of Hafnia alvei bacteremia in a pediatric cardiac surgery unit]. / Reporte de cuatro casos clínicos de bacteriemia por Hafnia alvei en una unidad cardio-quirúrgica pediátrica.

INTRODUCTION: The gram-negative bacillus Hafnia alvei is the only species of the genus Hafnia, family Enterobacteriaceae. It occasionally behaves as an opportunistic pathogen in humans, causing intestinal and respiratory infection and sepsis. It rarely causes bacteremia, usually of unknown focus. OBJECTIVE: To describe a nosocomial outbreak of four pediatric patients with bacteremia by Hafnia alvei. METHODS: Descriptive study using clinical records of pediatric patients diagnosed with Hafnia alvei bacteremia in a pediatric cardio surgical unit, in October 2008. RESULTS: The attack rate was 4/8 (50%), lethality rate 2/4 (50%) and mortality 2/8 (25%). The microbiological study and pulsed-field gel electrophoresis confirmed the same clonal bacterial strain. DISCUSSION: The source of bacteremia was identified only in two patients and was associated with central venous catheters. The other two cases had no known infectious source. Epidemiological surveillance of emerging agents must be maintained.

Analysis of molecular epidemiology of Chilean Salmonella enterica serotype enteritidis isolates by pulsed-field gel electrophoresis and bacteriophage typing.

Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype Enteritidis subtypes were associated with epidemic changes.

Salmonella enteritidis, un patógeno entérico ligado a la industria de los alimentos / Salmonella enteritidis, an enteric pathogen related to the industry of foods

Chile ha experimentado un cambio epidemiológico en la última década con la desaparición progresiva de la fiebre tifoidea, causada mayoritariamente por Salmonella Typhi y la emergencia epidémica de Salmonella Enteritidis, un agente de diarrea sin tratamiento antibiótico eficaz y ligado estrechamente a productos avícolas contaminados e inadecuadamente preparados. La fiebre tifoidea ha disminuido su importancia debido al desarrollo humano experimentado en Chile con un alto grado de cobertura de agua potable y de manejo de excretas que, en conjunto con un mayor nivel de educación, han limitado la contaminación del ambiente por este agente y la adquisición de él por huéspedes susceptibles. A pesar de este notable avance, un nuevo serotipo de Salmonella ha irrumpido en Chile, denominado Enteritidis, que ha logrado aprovechar el nuevo escenario obtenido con la industrialización avícola donde miles de aves convivenen pequeños espacios, facilitando la infección cruzada entre ellas. La contaminación intermitente de huevos, ya sea por vía transovárica o superficial, ha permitido la llegada de este agente en forma errática, pero persistente al ser humano. Este nuevo panorama obliga a que nuestro país adopte estrategias de prevención que involucran a productores, distribuidores y consumidores de productos avícolas