Molecular characterization and resistance profile of Salmonella Enteritidis PT4 and PT9 strains isolated in Brazil

Abstract

A total of 41 Salmonella Enteritidis strains, including phago-types (PTs) PT4 and PT9, were characterized by antimicrobial resistance profiles and PFGE. Of these strains, 34 were isolated from patients and foods, and 7 were of poultry origin. All strains were susceptible to ampicillin, chloramphenicol, cefotaxime, ciprofloxacin and trimethoprim/sulfamethoxazole, and 41.5 % (n517) were resistant to nalidixic acid. PFGE analysis using XbaI and SpeI restriction enzymes resulted in X1S1 as the prevalent pattern, which was present in 48.8 % (n520) of epidemic strains and in one strain isolated from discarded hatching eggs. Distinct patterns were found for the other strains isolated from poultry (X3S1, X8S8, X11S12, X11S13, X16S1 and X13S15). The S. Enteritidis PT9 strains associated with outbreaks of salmonellosis were highly similar (¢0.90), suggesting clonality. The PFGE genotypes were related to the PTs, and it was possible to differentiate strains isolated from patients with salmonellosis from other strains of non-epidemic origin. The PFGE results suggested that the S. Enteritidis strains of poultry origin were a possible source of human salmonellosis during the study period. INTRODUCTIONSalmonella species are associated with food-borne diseases worldwide. Foods of animal origin, such as poultry meat, eggs and their products, are frequently implicated in outbreaks (Clavijo et al., 2006). In the period 1999-2008, Salmonella species were responsible for 1408 (23.2 %) of the 6062 outbreaks investigated in Brazil, and Salmonella species were responsible for 267 (43. According to epidemiological data from the Central Laboratory of Parana State (LACEN), egg products were associated with 45.0 % of the salmonellosis outbreaks occurring from 1999 to 2008, and Salmonella enterica subsp. enterica serovar Enteritidis was the predominant serovar found in patient samples (87.8 %) and foods (80.6 %) .Phenotypic methods, such as phago-typing, antimicrobial resistance profiling and molecular methods, including analysis of the macrorestriction pattern of chromosomal DNA after PFGE, have been used to characterize S. Enteritidis strains. PFGE has been widely utilized in the molecular characterization of Salmonella species due to the stability of patterns, reproducibility and excellent discriminatory power (Ribot et al., 2002;Peters et al., 2003;Woo, 2005;Zou et al., 2010).Salmonella strains isolated from different sources in the same temporal period and from the same geographical location are likely to be epidemiologically related and to have an identical PFGE restriction pattern independent of the restriction enzyme employed (Tenover et al., 1995). PFGE is capable of discriminating strains of Salmonella of the same serovar and phago-type (PT) (Ahmed et al., 2000; Liebana et al., 2001).The aim of the present study was to characterize S. Enteritidis PT4 and PT9 strains of poultry origin or isolated from patients and foods involved in salmonellosis outbreaks by antimicrobial resistance profiles and PFGE patterns. An epidemiological co...

Lipids, pH, and Their Interaction Affect the Inhibitory Effects of Carvacrol against Salmonella Typhimurium PT4 and Escherichia coli O157:H7

“…Salmonella enterica serovar Typhimurium phage-type (PT) 4 ( S. Typhimurium PT4) isolated from chicken meat involved in outbreak occurred in the South of Brazil ( Kottwitz et al, 2011 ) and E. coli O157:H7 isolated from food sample (kindly provided by Prof. Anderson de Souza Sant’Ana, Quantitative Food Microbiology Laboratory, Food Engineering Faculty, São Paulo, Brazil) were used as test strains. Stocks were maintained in cryovials at -20°C in BHIB containing glycerol (20 mL/100 mL).…”

Comparison of four molecular methods to typeSalmonellaEnteritidis strains

“…Enteritidis strains, complementing the phenotypic assays. However, some studies have presented variable results related to the ability of specific techniques to differentiate the relatively genetically homogeneous serovar Enteritidis .…”

Molecular characterisation ofSalmonellastrains isolated from outbreaks and sporadic cases of diarrhoea occurred in Paraná State, South of Brazil

“…1) were associated with seven of eight outbreaks caused by Salmonella Enteritidis. There is still few studies on molecular typing of Salmonella isolates in Brazil [35][36][37][38] but apparently the same PFGE profile was also the most common among Salmonella Enteritidis strains associated with foodborne outbreaks occurred in Rio Grande do Sul State, southern Brazil [24], suggesting the propagation of one clone of the bacteria in the south of the country. Interestingly, most Salmonella Enteritidis isolated from sporadic cases in Taiwan presented the PFGE profile apparently identical to PA found in this study [39].…”