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1.
The Phene Plate system for typing Salmonella serotypes (PhP-S) is a simple automated typing method based on biochemical fingerprinting. It gives a quantitative value of the metabolism of various substrates by measuring the speed and intensity of each reaction. The ''biochemical fingerprint'' of each isolate is used to calculate similarities among the tested strains with a personal computer program. We used this system to examine a collection of 86 strains of Salmonella enteritidis isolated from human sporadic cases in Germany between 1980 and 1992. Twenty-three biochemical phenotypes (BPTs) consisting of 9 common (C) and 14 single (S) BPTs were identified. BPTs C2 and C4 containing 20 and 36 strains respectively accounted for 65% of the isolates. Strains of BPT C2 were found over a wide period of time whereas strains of BPT C4 were isolated during the period between 1988 and 1992. With phage typing, 11 discrete phage types (PTs) and 18 strains designated as non-specific type (NST) were identified. PTs 4 and 8 with 39 and 17 strains respectively were the dominant PTs. Strains of PT 8 were isolated over a wide period of time whereas all (except one) strains of PT 4 were isolated between 1988 and 1992. Combination of biochemical fingerprinting and phage typing divided the strains into 25 phenotypes (BPT:PTs). Whilst phenotype C2:8 was found over a number of different years, phenotype C4:4 was isolated only between 1988 and 1992. These findings indicate the presence of one persistent and one recently emerged phenotype among S. enteritidis strains in Germany.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

2.
The study aimed at specifying the value of two traditional methods of typing, using the collection of 241 strains of Salmonella Enteritidis isolated from people and animals in the Lublin area in 1994-1995 from the occasional cases of infections. There were 8 phage types identified among the examined strains. Phage types PT 6 (40.24% of strains) and PT 7 (29.46%) were the most numerous ones. Salmonella Enteritidis was numbered among 38 profiles on the basis of the analysis of resistance to 15 antimicrobial agents. It was found that nitrofurantoin had the lowest efficacy in vitro in relation to the examined collection of Salmonella isolates. High percentage of strains were characterized by lack of susceptibility to streptomycin, neomycin, cefixime, tetracycline and canamycine. While analyzing the profiles of resistance to chemiotherapeutics and the expression of phage type of the examined strains it was observed that only 14.1% of all strains showing resistance to nitrofurantoin represented at the same time phage type PT 6, whereas 10.8% of strains belonging to the same resistance profile indicated PT 7 phage type. In correlated analysis of resistance to chemiotherapeutics and phage type expression of the examined collection of 241 isolates of Salmonella Enteritidis, 18.3% of strains showed distinct and unique set of these two features, which can be used in epidemiological investigations for the preliminary characterization of the bacterial population.  相似文献   

3.
The comparison of two phage typing schemes for Salmonella enteritidis was performed. A total of 517 strains were phage-typed according to the schemes of Lalko [27] and Ward et al. [21]. Strains were isolated from food-poisoning outbreaks and other common sources in Poland, between 1986–1995. Above 99% of all strains tested were differentiated to the definitive phage type using the Lalko collection of typing phages. Phage types 1 and 7 (PTs 1, 7) were the most isolated. The typing phages of Ward enabled to assign 56.5% of all strains (a total of 14 phage types were presented), 37.1% – reacted with phages without showing any of the designated phage types and 6.4% were untypable. Phage type 8 (PT8) predominated. The majority of Salmonella enteritidis strains from one phage type outbreaks of Lalko presented different types of lytic reactions with the Ward phages. Only the correspondence of Salmonella enteritidis PT7 of Lalko with PT8 of Ward et al. [21] was observed.  相似文献   

4.
The plasmid pOG670, a 54 kb, conjugative plasmid that specifies resistance to ampicillin and kanamycin and belonging to the incompatibility group X (IncX), was transferred into 10 isolates of Salmonella enterica serotype Enteritidis belonging to 10 different phage types (PT1, 2, 3, 4, 8, 9, 9b, 10, 11 and 13). Acquisition of the plasmid by these strains did not result in the loss of any resident plasmids but resulted in phage type conversion in 8 of the 10 strains (PT1, 2, 4, 8, 9, 9b, 10 and 11). The observed changes in phage type were found to result from the loss of sensitivity to 3 of the 10 typing phages used (phages 3, 5 and 7). Where the conversion resulted in a change to a defined phage type, both the new and original PTs belonged to the same, previously described, evolutionary lines. Enteritidis PTs 1, 4 and 8, commonly associated with poultry world-wide, were converted to PTs 21, 6 and 13a respectively. The results indicate a different route for phage type conversion Enteritidis from others reported in the literature and, although IncX plasmids are not normally present in PT8 or PT13a, may suggest a possible mechanism/link connecting these phage types.  相似文献   

5.
Mouse virulence and the ability to adhere to, and invade cultured MDCK cells were investigated in 38 phage type reference strains of Salmonella enterica serotype Enteritidis and correlated with genomic lineage. The genomic lineage of 11 of the strains was determined in the present study; one IS200 and one ribotype pattern that had not been reported previously were observed. Log c.f.u. in the spleen 10 days post intraperitoneal (i.p.) infection with 3x10(3) bacteria (logVC10) varied between 2.9 and 8.7. The reference strains of PT7 and PT23 were found to be semi-rough and were of low virulence. All other strains possessed smooth LPS. Within each of the two major clonal lines, as well as among phage types outside these, both highly virulent and moderate to low virulent strains were present. While all strains of PT1, PT2 and PT8 were highly virulent, low virulent strains were detected in PT4 and PT13. The ability to adhere to, and invade MDCK cells varied between phage types (adherence between 13 and 61% of the inocula and invasion between 4 and 151% of the adherent cells). The results of the cell culture experiments did not correlate with the results of mouse virulence tests. No correlation between clonal lineage and virulence was found within S. Enteritidis. It seems most likely that some strains have lost some of the essential factors enabling this serotype to cause successful systemic infection.  相似文献   

6.
Phage typing of 741 isolates of Salmonella enterica serotype Enteritidis from the slovak Republic in 1995 has been carried out using the scheme of Ward and colleagues (1987). 202 strains (51 isolated from food) were from 9 outbreaks, 536 isolates were from sporadic cases and 3 isolates were from nosocomial infections of new-born babies. 704 isolates (95%) from all sources were typeable and belonged to 7 different phage types (PTs). PT8 was the phage type most frequently identified (72.6%). Other epidemiologically relevant phage types were PT2 (8.5%), 4 (7.9%) and 1 (4.2%). With an incidence of 1.3--0.1% isolates of PTs 21, 6, 9 were found. 26 (3.5%) isolates were designated RDNC and 11 (1.5%) were untypeable.  相似文献   

7.
Argentina has a high incidence of hemolytic uremic syndrome (HUS); 12.2 cases per 100,000 children younger than 5 years old were reported in 2002. Shiga toxin (Stx)-producing Escherichia coli (STEC) is the primary etiologic agent of HUS, and STEC O157 is the predominant serogroup isolated. The main objective of the present work was to establish the phenotypic and genotypic characteristics of the STEC strains in general isolated from Argentine children during a prospective study and the clonal relatedness of STEC O157:H7 strains using subtyping techniques. One hundred and three STEC strains isolated from 99 children were included. The phenotypic and genotypic features were established, and a polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) was performed to determine stx2 variants. The clonal relatedness of E. coli O157 isolates was established by phage typing and pulsed-field gel electrophoresis (PFGE). The 103 STEC strains belonged to 18 different serotypes, and 59% were of serotype O157:H7. Stx2 was identified in 90.3%, and stx1 in 9.7%. Among the 61 STEC O157 strains, 93.4% harbored the stx2/stx2vh-a genes; PT4 (39.3%) and PT2 (29.5%) were the predominant phage types. Using PFGE with the enzyme XbaI, a total of 41 patterns with at least 80% similarity were identified, and seven clusters with identical profiles were established. Some of the clusters were further split by PFGE using BlnI as the second enzyme. Isolates with indistinguishable PFGE patterns were with one exception also indistinguishable by phage typing and stx genotyping. These findings confirmed that some isolates were genetically related. However, no epidemiological linkages were identified. STEC strains with different genotypes and belonging to diverse serotypes were isolated in Argentina. Some STEC O157 strains could not be distinguished by applying subtyping techniques such as PFGE and phage typing.  相似文献   

8.
Spread of multidrug-resistant strains of Salmonella enterica serotype Typhimurium (S. typhimurium) is increasingly reported worldwide. The presence of a pattern of resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline (ACSSuT), in some cases associated to trimethoprim and infrequently to quinolones, is of particular concern. This resistance pattern appears to be chromosomally encoded and, in most epidemiological studies, closely related to definitive type 104 (DT104).In southern Italy multidrug-resistant isolates of S. typhimurium had been identified since 1980, but only during 1992 S. typhimurium strains with chromosomally encoded drug resistance were first isolated from domestic animals.One hundred fifty-five isolates – 52.5% of the multidrug-resistant strains identified in the years 1992–1997 – were submitted to phage typing and plasmid profile analysis. Ribotyping was also performed in comparison with a random sample of 150 strains susceptible or resistant to three or less antibiotics identified in the same interval of time.Four ribotypes (RTs) -1, 5, 8, and 48 – included approximately 90% of the multiresistant strains, RT8 accounting for 61.2%. Phage type (PT) 193 is the most prevalent phage type.Phage typing and ribotyping suggest that few bacterial clones are involved in spread of multi- drug-resistant S. typhimurium strains in southern Italy.  相似文献   

9.
Shiga toxin-producing Escherichia coli (STEC) cause nonbloody (NBD) and bloody diarrhea (BD), and hemolytic uremic syndrome (HUS). Cattle have been described as their main reservoir. STEC O157:H7 is recognized as the predominant serotype in clinical infections, but much less is known about the dominant subtypes in humans and animals or their genetic relatedness. The aims of this study were to compare the STEC O157 subtypes found in sporadic human infections with those in the bovine reservoir using stx-genotyping, phage typing, and XbaI-pulsed-field gel electrophoresis (PFGE), and correlate the subtypes with the severity of clinical manifestations. The 280 STEC O157:H7 strains collected included in this study were isolated from HUS (n=122), BD (n=69), and NBD (n=30) cases, and healthy carriers (n=5), and from bovines (n=54) in the abattoirs. The stx-genotyping showed that stx?/stx(2c(vh-a)) was predominant in human (76.1%) and in bovine strains (55.5%), whereas the second more important genotype was stx? (20.8%) in human and stx(2c(vh-a)) (16.7%) in cattle strains. In human strains, PT4 (37.6%), PT49 (24.3%), and PT2 (18.6%) were the most frequent PTs (80.5%). In bovine isolates, PT2 (26%), PT39 (16.7%), and PT4 and PT49 (11.1% each) were predominant. By XbaI-PFGE, all 280 strains yielded 148 patterns with 75% similarity, and 169 strains were grouped in 37 clusters. Identical PT-PFGE-stx profile combinations were detected in strains of both origins: PT4-AREXH01.0011-stx?/stx(2c(vh-a)) (12 humans and one bovine), PT4-AREXH01.0543-stx?/stx(2c(vh-a)) (one human and four bovines), PT2-AREXH01.0076-stx?/stx(2c(vh-a)) (one human and four bovines), PT49-AREXH01.0175-stx?/stx(2c(vh-a)) (seven humans and one bovine), and PT49-AREXH01.0022-stx?/stx(2c(vh-a)) (seven humans and one bovine). No correlation was found among the stx-genotypes, the phage type, and the clinical symptoms.  相似文献   

10.
Salmonella enterica serotype Enteritidis isolates of phage types (PTs) PT1, PT4, PT13a and PT22 derived from sporadic cases and outbreaks of food poisoning in Japan during 1994 and 1995 were analysed by pulsed-field gel electrophoresis (PFGE). While PT1 strains from 5 different outbreaks showed 14 PFGE patterns, 5 PFGE patterns were observed among PT4 isolates from 5 different outbreaks and 6 independent isolates from imported chicken. Interestingly, 8 out of 9 PT4 strains associated with foreign travel to Southeast Asia were indistinguishable in PFGE pattern from 5 independent isolates of imported chicken from England. Although both PT13a and PT22 were first reported in Japan in 1994, PT22 showed various PFGE patterns compared to PT13a which had the same pattern within an outbreak, unlike PT1. These results could indicate that multiple clonal lines of PT1 and PT22 had already spread while relatively fewer clonal lines of PT4 and PT13a might exist in Japan.  相似文献   

11.
After an upward trend paralleling that occurring in most European countries, including Italy, since October 2002 Salmonella enterica serotype Enteritidis (S. Enteritidis) has again gained the first position among outbreak and sporadic human isolates of Salmonella in Sicily. Because phage typing of S. Enteritidis has many technical and epidemiological limitations and molecular methods have proved to be poorly discriminative for this organism, multiple typing, using phage typing together with pulsed field gel electrophoresis (PFGE) and plasmid profiling on a sample of fifty human and poultry isolates identified during the period October 2002 to May 2003 in Sicily, was chosen as the most valuable strategy to explore key features of this new epidemic wave. Although the limited number of strains imposes a cautious interpretation of the results, an apparently increasing phage type heterogeneity has emerged with rise in PT6 as the more striking event. While PFGE has confirmed the findings by other authors about the close genetic homogeneity between PT4 and PT6, plasmid profiling has provided discriminative patterns for PT6 strains. Combined phenotypic and genotypic profiles are necessary for epidemiological studies and public health investigations on S. enteritidis.  相似文献   

12.
Campylobacter is the most commonly reported cause of gastro-intestinal infection in England and Wales, with over 50,000 reported cases in 1997. The majority of human campylobacter isolates in England and Wales are C. jejuni (c. 90%) with most of the remainder being C. coli. We describe the use of phage typing as an extension to serotyping for more detailed characterization within these two species. The scheme was piloted during a study of 2407 C. jejuni and 182 C. coli strains isolated in Wales between April 1996 and March 1997. Fifty-seven C. jejuni phage types were identified, with the ten most prevalent phage types accounting for 60% of isolates tested; 16% of isolates were untypable. The most common phage type was PT 1 which represented c. 20% of isolates. A further 7% of isolates reacted with the phages but did not conform to a designated type (RDNC). Only 12 phage types were identified among C. coli, with the two most common types, PT 2 and PT 7 accounting for 75.2% of isolates. When used in conjunction with serotyping, the ability of phage typing to identify between 6 and 29 subtypes within each of the predominant HS types has enabled a further level of discrimination to be achieved that enhances the epidemiological typing of C. jejuni and C. coli.  相似文献   

13.
Since 1994 an extensive epidemic of infections with Salmonella enteritidis (S. enteritidis) has affected Chile. In order to understand the diversity of infective sources, the possible origin of the epidemic, and the epidemiological relationships between clinical, food, and poultry isolates, we carried out phage typing of three groups of samples: 1) 310 S. enteritidis clinical samples collected between 1975 and 1996, 2) 47 food isolates obtained during S. enteritidis outbreaks, and 3) 27 strains isolated in surveillance studies of poultry-raising establishments. With the clinical samples, a total of 13 phage types were identified, 2 isolates could not be typed, and 1 was considered atypical. The phage types that were identified most frequently were 1 (56.8%) and 4 (31.3%), trailed by type 8 (4.8%) and type 28 (1.9%). Over time and in different regions of the country there were major changes in the distribution of the phage types. In the first years of collection the only phage types registered were 8 and 28, which disappeared around 1980 and then began reappearing sporadically in 1996. With the gradual S. enteritidis expansion that started in 1988, in the central and southern areas of the country phage type 4 began to appear; that type had not been found before in Chile. In 1991 in the northern area of the country phage type 1 began to predominate; it was another type that had not been reported before in Chile. In the food isolates the only phage types identified were 1 and 4, which were also the most common in the poultry isolates. Phage typing of S. enteritidis has proved to be useful in guiding the epidemiological analysis of the infections caused by this pathogen.  相似文献   

14.
The diversity among 1354 strains of Salmonella enterica subsp. enterica, serotype Enteritidis (n = 847) and Typhimurium (n = 507) isolated in Finland in 1991-2002 (n = 608) and in 2003 (n = 746) were studied. The former strains were studied retrospectively by phage typing and pulsed-field gel electrophoresis (PFGE) harmonized in the European Salm-gene project. The latter strains were studied prospectively, and the results correlated to their antimicrobial susceptibility and association with travel to popular tourist destinations. During both periods, S. Enteritidis phage types (PTs) PT1 and PT4, and S. Typhimurium definite types (DTs) DT1 and DT104 were the major phenotypes. SENTXB.0001 was the dominating single PFGE type among S. Enteritidis strains (40% in 1991-2002; 57% in 2003), and accounted correspondingly for 23% and 63% of the PT1 strains, and 81% and 88% of the PT4 strains. No PFGE types dominated among the S. Typhimurium strains but a correlation was found between certain phage and PFGE types: among DT1 strains, STYMXB.0098 accounted for 66% (1991-2002) and 98% (2003) and among the DT104 strains STYMXB.0001 accounted for 84% and 97% in the two time periods, respectively. Of the S. Enteritidis strains isolated in 2003, 91% were associated with travel, most commonly to Spain, Greece, and Bulgaria. SENTXB.0001 was the major Salmonella PFGE type in these countries. In contrast, most (55%) S. Typhimurium strains were of domestic origin. While only 1.3% of the S. Enteritidis strains were multiresistant and 24% were resistant to nalidixic acid only, 30% of the S. Typhimurium strains were multiresistant. Among the multiresistant S. Typhimurium strains, R-type ACSSuT and PFGE type STYMXB.0001 of the DT104 complex dominated.  相似文献   

15.
A culture taken from a nursing home resident as part of a S. enteritidis outbreak was found to have a mixed infection due to three different strains of S. enteritidis. One of the three strains belonged to phage type (PT) 4, one to PT6 and one reacted with phages but did not conform to any typing scheme (RDNC). All three strains had the 38.9 megadaltons (MDa) plasmid found in the isolates from the outbreak-related cases, in addition the PT6 and RDNC strains harboured a 69.9 MDa plasmid. The importance of phage typing and plasmid analysis for S. enteritidis strain characterization and their epidemiologic and bacterial significance are discussed.  相似文献   

16.
During 2002-2003 increased numbers of notified salmonellosis due to S. enterica serovar Agona were observed in Germany. In order to understand the recent spread of this serovar and to trace the route of infection to its source, a new phage-typing scheme and pulsed field gel electrophoresis (PFGE) were used to analyse these isolates. By using 14 bacteriophages, 52 phage types were distinguished among the S. Agona strains. PFGE also differentiated 52 different patterns. A combination of both methods generated 94 clonal types among 165 S. Agona strains originating from Germany and other countries including the United States, United Arab Emirates, Turkey, India, Austria and Finland, indicating a great biological diversity within this serovar. However, 36 recent S. Agona isolates from infantile gastroenteritis in Germany, from an untreated batch of aniseed imported from Turkey and from fennel-aniseed-caraway infusion (packed in tea bags) revealed clonal identity indicating their epidemiological relatedness as a new source of infection. It is suggested that strains of S. Agona will continue to be of public health concern, and that phage typing together with PFGE typing should be applied as reliable and rapid tools for epidemiological subtyping and future monitoring.  相似文献   

17.
Investigations were performed by the Laboratory of Enteric Pathogens on Vero cytotoxin-producing Escherichia coli (VTEC) in England and Wales from 1992-4. Bacterial isolates, faeces and sera obtained from patients with diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome were examined. Using serotyping, Vero cytotoxin gene probing and serodiagnostic tests for E. coli O157, evidence of infection was detected in 543, 434 and 491 individuals in 1992, 1993 and 1994 respectively; VTEC of serogroup O157 were isolated from 470, 385 and 411 cases. The O157 VTEC strains belonged to at least 19 different phage types (PT) although 84% belonged to PT2, PT49, PT8, PT1 or PT4. Antibodies to E. coli O157 lipopolysaccharide were detected in 13% of the cases. The average annual rate of infection with O157 VTEC was 0.83/100000 and 12% of the 1458 individuals with evidence of infection with VTEC or E. coli O157 developed haemolytic uraemic syndrome. There were at least 18 general outbreaks and many family outbreaks.  相似文献   

18.
Salmonella enterica serovar Infantis (Salmonella Infantis) is consistently isolated from broiler chickens, pigs, and humans worldwide. This study investigated 93 epidemiologically unrelated Salmonella Infantis strains isolated in Germany between 2005 and 2008 in respect to their transmission along the food chain. Various phenotypic and genotypic methods were applied, and the pathogenicity and resistance gene repertoire was determined. Phenotypically, 66% of the strains were susceptible to all 17 antimicrobials tested, while the others were almost all multidrug-resistant (two or more antimicrobial resistances), with different resistance profiles and preferentially isolated from broiler chickens. A number of phage types (PTs) were shared by strains from pigs, broiler chickens, and humans (predominated by PT 29). One, PT 1, was only detected in strains from pigs/pork and humans. Pulsed-field gel electrophoresis (PFGE) subdivided strains in seven different clusters, named A-G, consisting of 35 various XbaI profiles with coefficient of similarity values of 0.73-0.97. The majority of XbaI profiles were assigned to clusters A and C, and two predominant XbaI profiles were common in strains isolated from all sources investigated. Multi-locus sequence typing (MLST) analysis of selected strains representing the seven PFGE clusters revealed that they all belonged to ST32. The pathogenicity gene repertoire of 37 representative Salmonella Infantis strains analyzed by microarray was also identical. The resistance gene repertoire correlated perfectly with the phenotypic antimicrobial resistance profiles, and multidrug-resistant strains were associated with class 1 integrons. Overall, this study showed that two major closely related genotypes of Salmonella Infantis can transmit in Germany to humans through contaminated broiler meat or pork, and consequently presents a hazard for human health.  相似文献   

19.
A model system for the study of phage conversion of Salmonella enterica serotype Enteritidis is reported. Temperate phages 1,2,3 and 6 from the phage typing scheme were used to convert several individually recognized phage types into others. Phage type 4 was converted to PT8, PT6a to PT4, PT6a to PT7, PT13 to PT13a and PT15 to PT11; some new phage lysis patterns were also detected. This model was used to examine the relationships between phage types within a previously defined clonal lineage, SECLIII, to establish whether or not Enteritidis like Salmonella enterica serotype Typhi and Salmonella enterica serotype Paratyphi B possessed type determining phages. We were able to convert PT1 to PT20, and PT15 to PT11.  相似文献   

20.
Salmonella infections in Antarctic wildlife were first reported in 1970 and in a search for evidence linking isolations with exposure to human activities, a comparison was made of serovars reported from marine fauna in the Antarctic region from 1982-2004 with those from marine mammals in the Northern hemisphere. This revealed that 10 (83%) Salmonella enterica serovars isolated from Antarctic penguins and seals were classifiable in high-frequency (HF) quotients for serovars prevalent in humans and domesticated animals. In Australia, 16 (90%) HF serovars were isolated from marine birds and mammals compared with 12 (86%) HF serovars reported from marine mammals in the Northern hemisphere. In Western Australia, HF serovars from marine species were also recorded in humans, livestock, mussels, effluents and island populations of wildlife in urban coastal areas. Low-frequency S. enterica serovars were rarely detected in humans and not detected in seagulls or marine species. The isolation of S. Enteritidis phage type 4 (PT4), PT8 and PT23 strains from Adélie penguins and a diversity of HF serovars reported from marine fauna in the Antarctic region and coastal areas of Australia, signal the possibility of transient serovars and endemic Salmonella strains recycling back to humans from southern latitudes in marine foodstuffs and feed ingredients.  相似文献   

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