Tracing lineage by phenotypic and genotypic markers in Salmonella enterica subsp. enterica serovar 1,4,[5],12:i: - and Salmonella Typhimurium isolated in state of São Paulo, Brazil

Fifty-three Salmonella 1,4,[5],12:i:- and 45 Salmonella Typhimurium strains were characterised using phage typing, plasmid profiles and pulsed-field gel electrophoresis (PFGE) for comparison. The majority of the strains were subdivided into definitive type (DT) 41 (22.6 percent) and DT 193 (18 percent) and the 60-MDa plasmid was detected in 94.3 percent and 84.4 percent of strains, respectively. Genetic diversity was observed among all strains and 90 percent presented a > 70 percent similarity through PFGE analysis. These results suggest a close relationship between Salmonella 1,4,[5],12:i:- and Salmonella Typhimurium at the serotype level.

Salmonella serovars isolated from humans in São Paulo State, Brazil, 1996-2003 / Sorovares de Salmonella isolados de humanos no Estado de São Paulo, Brasil, 1996-2003

Salmonellosis remains an important cause of diarrheal illness in humans in São Paulo State, Brazil. In this study were identified 3554 Salmonella isolates from human infections, during the period 1996-2003. Among 68 different serovars determined, S. Enteritidis was the most frequent one in gastrointestinal and extra-intestinal infections accounting for 67.4 percent of all isolates. S. Typhimurium and S. enterica subsp. enterica (4,5,12:i:-) were most frequently isolated from children aged < 1-4 year-old, in contrast, people with S. Enteritidis infections were most likely to be 20-50 year-old. In our geographic area the continued laboratorial surveillance of salmonellosis, including serotyping, has showed the trends in Salmonella serovars causing infections in humans throughout the time.

A salmonelose permanece uma importante causa de doença diarréica em humanos no Estado de São Paulo, Brasil. Nesse estudo foram identificados 3554 isolados de Salmonella de infecções humanas, durante o período 1996-2003. Entre os 68 diferentes sorovares determinados, S. Enteritidis foi predominante em infecções gastrointestinais e extra-intestinais, responsável por 67.4 por cento de todos os isolados. S. Typhimurium e S. enterica subsp. enterica (4,5,12:i:-) foram mais freqüentemente isolados de crianças com idade de < 1 a 4 anos, em contraste, infecções por S. Enteritidis foram predominantes em pessoas entre 20 e 50 anos. A contínua vigilância laboratorial das salmoneloses, incluindo a sorotipagem, tem evidenciado os sorovares de Salmonella causando infecções humanas em nossa área geográfica ao longo do tempo.

Multiplex PCR identification of the atypical and monophasic Salmonella enterica subsp. enterica serotype 1,4,[5],12:i:- in São Paulo State, Brazil: frequency and antibiotic resistance patterns

Salmonella spp. é o agente etiológico da salmonelose, zoonose mundialmente distribuída e responsável por surtos de doenças transmitidas por alimentos e doenças clínicas. Sorologicamente, Salmonella enterica subsp. enterica sorotipo 1,4,[5],12:i:- correspondeu a 8,8 por cento e 1,6 por cento das cepas de Salmonella de origem humana e não-humana, respectivamente, isoladas no Estado de São Paulo, no decênio 1991-2000. Aproximadamente 28,6 por cento destas cepas amplificaram o fragmento correspondente a H:1,2 (fase flagelar dois) em testes de PCR e foram, então, identificadas como S. Typhimurium. Das 369 cepas negativas em PCR, 36,3 por cento apresentou resistência antimicrobiana, incluindo multirresistência a ampicilina, cloranfenicol, sulfonamidas, tetraciclina e estreptomicina.

Phenotypic and molecular characterization of Salmonella Enteritidis strains isolated in São Paulo, Brazil

In São Paulo State, Brazil, the epidemic increase in isolation of Salmonella Enteritidis has been observed since 1994. A total of 105 S. Enteritidis strains (72 from human and 33 from non-human sources) isolated during the period 1975-1995, previously characterized by phage typing, was analyzed by antimicrobial susceptibility, plasmid profile, and ribotyping. Over 70 percent of the strains were susceptible to all antimicrobial agents tested, however, multiple resistance to antimicrobials was observed among the studied strains, mainly those from hospitalized patients. Phage type 8 (PT-8) was predominant among the strains isolated during the period of 1975-1992, but in the following years, PT-4 was the most frequent phage type identified. Seven different plasmid profiles were detected and 96 percent of the isolates harbored a plasmid of approximately 36 MDa. Ribotyping discriminated fourteen ribotypes (R1 to R14) among the strains examined. By analysis of dendrogram the strains were included in three groups with similarity level of 60 percent. The obtained results indicate that, a single ribotype (R11), determined for PT-4 strains isolated from 1993, characterizes the epidemic clone of S. Enteritidis in our region

Salmonella: sorotipos identificados na regiäo de Säo José do Rio Preto/SP, no período de 1990-1999 / Salmonella: serotypes identified in the Säo José do Rio Preto area, SP, during the period of 1990-1999

No período de janeiro de 1990 a dezembro de 1999, no Instituto Adolfo Lutz - Lab. I de Säo José do Rio Preto-SP, foram isoladas 324 cepas de salmonella, sendo 155 de infecçöes humanas e 169 de alimentos destinados ao consumo humano. Dos 17 diferentes sorotipos identificados a partir de infecçöes humanas, S. enterica subsp. enterica sorotipo enteritidis (S. enteritidis) foi o predominante 75,0(por cento). O material fecal representou a principal fonte de isolamento das cepas, principalmente pela ocorrência dos vários surtos de doenças veiculadas por alimentos (DVA). A partir dos alimentos, 26,6(por cento) deles envolvidos em surtos de DVA, foram identificados 30 diferentes sorotipos, também com a predominância de S. enteritidis 56,2(por cento). Os alimentos apresentando maior número de isolamentos de cepas de Salmonella foram a carne e seus derivados 59,7(por cento), seguidos por ovos e seus derivados 16,0(por cento), nos quais, S. enteritidis foi o sorotipo mais prevalente 57,4(por cento) e 81,5(por cento) respectivamente. Estes resultados demonstram que S. enteritidis permanece o sorotipo mais frequentemente isolado, tanto em infecçöes humanas quanto em alimento. Os alimentos mais comumente implicados em DVA ainda säo as carnes de aves e ovos, bem como os seus derivados, quando consumidos crus ou mal cozidos. (AU)

From January 1990 to December 1999, 324 Salmonella strains were isolated at InstitutoAdolfo Lutz ­ São José do Rio Preto­SP Lab. I, 155 from human infections and 169 from food for humanconsumption. S. enterica subsp. Enterica serotype enteritidis (S. enteritidis) was the most prevalentserotype (75.0%) among the 17 different ones identified in human infections. Fecal material representedthe main human source of the isolated strains, due to several foodborne outbreaks occurring in the periodunder study. Thirty different serotypes were identified in food, S. enteritidis being the prevailing one.About 26.6% of the analyzed foods were linked to foodborne outbreaks. Foods presenting the highest rateof isolated strains were meat and its products (59.7%), followed by eggs and egg products (16.0%). Theseresults show that S. enteritidis still remains as the most common serotype isolated from human sourcesand foods. Foods frequently implicated in foodborne outbreaks are chicken meat and eggs, as well as theirproducts, particularly raw and undercooked ones. (AU)

Characterization of lactose-fermenting Salmonella agona strains isolated in a pediatric unit

Eight lactose-fermenting Salmonella agona strains isolated in a pediatric unit were characterized by classic and molecular methods. The strains were classified as biotypes 1a, corresponding to the most frequen one in Brazil. None of the strains produced colicin. Multiple resistence to antimicrobials was observed among the strains studied, It was demonstrated that the lactose-fermenting character was encoded by a plasmid with spontaneous segregaton at a frequency of 1 percer center. This plasmid was transferable by conjugation at a frequency between 4x10(-8) and 5x10(-10). The lac+ plasmid, which molecular weight was approximately 90 MDa, encoded both lactose fermentation and multiple resistance to antimicrobials. Replicon typing showed that this plasmid did not belong to the known types, suggesting the present of a new replicon type. Classic methods showed that the studied strains had the same characteristics as the clone widely occurring in our area, differing only by lactose-fermenting ability. This conclusion was supported by the results of ribotyping study.