Development of a real-time PCR method for the genoserotyping of Salmonella Paratyphi B variant Java.

Discriminating between D-tartrate fermenting and non-fermenting strains of Salmonella enterica subsp. enterica serotype Paratyphi B is of major importance as these two variants have different pathogenic profiles. While D-tartrate non-fermenting S. Paratyphi B isolates are the causative agent of typhoid-like fever, D-tartrate fermenting isolates (also called variant Java) of the same serotype trigger the less dangerous gastroenteritis. The determination of S. Paratyphi B variants requires a time-consuming process and complex biochemical tests. Therefore, a quadruplex real-time PCR method, based on the allelic discrimination of molecular markers selected from the scientific literature and from whole genome sequencing data produced in-house, was developed in this study, to be applied to Salmonella isolates. This method was validated with the analysis of 178 S. Paratyphi B (D-tartrate fermenting and non-fermenting) and other serotypes reaching an accuracy, compared with the classical methods, of 98% for serotyping by slide agglutination and 100% for replacement of the biochemical test. The developed real-time PCR permits to save time and to obtain an accurate identification of a S. Paratyphi B serotype and its D-tartrate fermenting profile, which is needed in routine laboratories for fast and efficient diagnostics.

Multistate outbreak of Salmonella Paratyphi B variant L(+) tartrate(+) and Salmonella Weltevreden infections linked to imported frozen raw tuna: USA, March-July 2015.

Foodborne non-typhoidal salmonellosis causes approximately 1 million illnesses annually in the USA. In April 2015, we investigated a multistate outbreak of 65 Salmonella Paratyphi B variant L(+) tartrate(+) infections associated with frozen raw tuna imported from Indonesia, which was consumed raw in sushi. Forty-six (92%) of 50 case-patients interviewed ate sushi during the week before illness onset, and 44 (98%) of 45 who specified ate sushi containing raw tuna. Two outbreak strains were isolated from the samples of frozen raw tuna. Traceback identified a single importer as a common source of tuna consumed by case-patients; this importer issued three voluntary recalls of tuna sourced from one Indonesian processor. Four Salmonella Weltevreden infections were also linked to this outbreak. Whole-genome sequencing was useful in establishing a link between Salmonella isolated from ill people and tuna. This outbreak highlights the continuing foodborne illness risk associated with raw seafood consumption, the importance of processing seafood in a manner that minimises contamination with pathogenic microorganisms and the continuing need to ensure imported foods are safe to eat. People at higher risk for foodborne illness should not consume undercooked animal products, such as raw seafood.

What's in a Name? Species-Wide Whole-Genome Sequencing Resolves Invasive and Noninvasive Lineages of Salmonella enterica Serotype Paratyphi B.

UNLABELLED: For 100 years, it has been obvious that Salmonella enterica strains sharing the serotype with the formula 1,4,[5],12:b:1,2-now known as Paratyphi B-can cause diseases ranging from serious systemic infections to self-limiting gastroenteritis. Despite considerable predicted diversity between strains carrying the common Paratyphi B serotype, there remain few methods that subdivide the group into groups that are congruent with their disease phenotypes. Paratyphi B therefore represents one of the canonical examples in Salmonella where serotyping combined with classical microbiological tests fails to provide clinically informative information. Here, we use genomics to provide the first high-resolution view of this serotype, placing it into a wider genomic context of the Salmonella enterica species. These analyses reveal why it has been impossible to subdivide this serotype based upon phenotypic and limited molecular approaches. By examining the genomic data in detail, we are able to identify common features that correlate with strains of clinical importance. The results presented here provide new diagnostic targets, as well as posing important new questions about the basis for the invasive disease phenotype observed in a subset of strains. IMPORTANCE: Salmonella enterica strains carrying the serotype Paratyphi B have long been known to possess Jekyll and Hyde characteristics; some cause gastroenteritis, while others cause serious invasive disease. Understanding what makes up the population of strains carrying this serotype, as well as the source of their invasive disease, is a 100-year-old puzzle that we address here using genomics. Our analysis provides the first high-resolution view of this serotype, placing strains carrying serotype Paratyphi B into the wider genomic context of the Salmonella enterica species. This work reveals a history of disease dating back to the middle ages, caused by a group of distinct lineages with various abilities to cause invasive disease. By quantifying the key genomic differences between the invasive and noninvasive populations, we are able to identify key virulence-related targets that can form the basis of simple, rapid, point-of-care tests.

Molecular characterization of Salmonella paratyphi B dT+ and Salmonella Heidelberg from poultry and retail chicken meat in Colombia by pulsed-field gel electrophoresis.

Salmonella Paratyphi B dT+ variant (also termed Salmonella Java) and Salmonella Heidelberg are pathogens of public health importance that are frequently isolated from poultry. As a step toward implementing the Colombian Integrated Program for Antimicrobial Resistant Surveillance, this study characterized molecular patterns of Salmonella Paratyphi B dT+ and Salmonella Heidelberg isolated from poultry farms, fecal samples, and retail chicken meat using pulsed-field gel electrophoresis (PFGE). The objective of this study was to determine the genetic relationship among isolates and to determine potential geographically predominant genotypes. Based on PFGE analysis, both serovars exhibited high heterogeneity: the chromosomal DNA fingerprints of 82 Salmonella Paratyphi B dT+ isolates revealed 42 PFGE patterns, whereas the 21 isolates of Salmonella Heidelberg revealed 10 patterns. Similar genotypes of both serovars were demonstrated to be present on farms and in retail outlets. For Salmonella Paratyphi B dT+, closely genetically related strains were found among isolates coming from different farms and different integrated poultry companies within two departments (Santander and Cundinamarca) and also from farms located in the two geographically distant departments. For Salmonella Heidelberg, there were fewer farms with genetically related isolates than for Salmonella Paratyphi B dT+. A possible dissemination of similar genotypes of both serovars along the poultry production chain is hypothesized, and some facilitating factors existing in Colombia are reviewed.

[Molecular epidemiology, antimicrobial resistance and characterization of extended-spectrum beta-lactamases of Salmonella enterica serotype Paratyphi B clinical isolates]. / Salmonella enterica serotip Paratyphi B klinik izolatlarinin moleküler epidemiyolojisi, antimikrobiyal direnci ve genislemis spektrumlu beta-laktamazlarinin karakterizasyonu.

Although Salmonella enterica serotype Paratyphi B is the less frequently isolated serotype worldwide and in Turkey, it is the most common serotype in our hospital, with a marked increase in 2007. The purpose of this study was to investigate the antibiotic susceptibility and the extended spectrum beta-lactamase (ESBL) profile, and molecular epidemiology of S. Paratyphi B isolates detected in our hospital microbiology laboratory. Seventy isolates identified as S. Paratyphi B from 109 Salmonella isolates obtained from clinical specimens from different patients between October 2005 and December 2012, were included in the study. In addition to conventional methods, isolates were identified using the Phoenix automated microbiology system (Becton Dickinson, USA). Serotyping of the isolates was performed on the basis of slide agglutination and the Kauffmann-White scheme. The antibiotic susceptibility of the isolates was determined using the BD Phoenix' automated system and disk diffusion test. ESBL enzymes were investigated using the combined disk test, isoelectric focusing, polymerase chain reaction (PCR) and sequence analysis. The molecular epidemiology of the 51 isolates obtained between October 2005 and August 2008 was examined with pulsed-field gel electrophoresis (PFGE) using the XbaI enzyme. S. Paratyphi B isolates were obtained from 70 specimens (46 blood, 16 fecal, 4 bone marrow, 2 urine and 2 wound) each from different patients. Resistance to nalidixic acid was determined in 18.6%, resistance to ampicillin, cefotaxime and cefepime in 2.9% and to ceftazidime and co-trimoxazole in 1.4% of the isolates. ESBL production was detected only in two isolates; in one TEM-1 was accompanied by CTX-M-15 and in the other isolate CTX-M-3 was found. Forty-six of the 51 isolates (90%) were found to be genetically related by PFGE and were placed in cluster A. The distribution of the isolates in cluster A revealed six subtypes as A1 (n= 7), A2 (n= 11), A3 (n= 7), A4 (n= 18), A5 (n= 2) and A6 (n= 1). Three different patterns not related to the cluster A were determined in the remaining five isolates (two were B, one of each was C, D and E). In conclusion, although the rate of antibiotic resistance was low in the S. Paratyphi B isolates in our hospital, rare types of ESBLs such as CTX-M-3 and CTX-M-15 were detected in Salmonellae. As far as the current literature is considered, this is the first report in Turkey of blaCTX-M-15 in Salmonella spp. and blaCTX-M-3 genes in S. Paratyphi B. The results may indicate a possible future threat to the treatment of Salmonella infections. Since most of the isolates were genetically related, this might suggest an epidemic in our region.

The discrimination of d-tartrate positive and d-tartrate negative S. enterica subsp. enterica serovar Paratyphi B isolated in Malaysia by phenotypic and genotypic methods.

Serotyping is not sufficient to differentiate between Salmonella species that cause paratyphoid fever from the strains that cause milder gastroenteritis as these organisms share the same serotype Salmonella Paratyphi B (S. Paratyphi B). Strains causing paratyphoid fever do not ferment d-tartrate and this key feature was used in this study to determine the prevalence of these strains among the collection of S. Paratyphi B strains isolated from patients in Malaysia. A total of 105 isolates of S. Paratyphi B were discriminated into d-tartrate positive (dT+) and d-tartrate negative (dT) variants by two lead acetate test protocols and multiplex PCR. The lead acetate test protocol 1 differed from protocol 2 by a lower inoculum size and different incubation conditions while the multiplex PCR utilized 2 sets of primers targeting the ATG start codon of the gene STM3356. Lead acetate protocol 1 discriminated 97.1% of the isolates as S. Paratyphi B dT+ and 2.9% as dT while test protocol 2 discriminated all the isolates as S. Paratyphi B dT+. The multiplex PCR test identified all 105 isolates as S. Paratyphi B dT+ strains. The concordance of the lead acetate test relative to that of multiplex PCR was 97.7% and 100% for protocol 1 and 2 respectively. This study showed that S. Paratyphi B dT+ is a common causative agent of gastroenteritis in Malaysia while paratyphoid fever appears to be relatively uncommon. Multiplex PCR was shown to be a simpler, more rapid and reliable method to discriminate S. Paratyphi B than the phenotypic lead acetate test.

Human infections attributable to the D-tartrate-fermenting variant of Salmonella enterica serovar Paratyphi B in Germany originate in reptiles and, on rare occasions, poultry.

In this study, the population structure, incidence, and potential sources of human infection caused by the d-tartrate-fermenting variant of Salmonella enterica serovar Paratyphi B [S. Paratyphi B (dT+)] was investigated. In Germany, the serovar is frequently isolated from broilers. Therefore, a selection of 108 epidemiologically unrelated S. enterica serovar Paratyphi B (dT+) strains isolated in Germany between 2002 and 2010 especially from humans, poultry/poultry meat, and reptiles was investigated by phenotypic and genotypic methods. Strains isolated from poultry and products thereof were strongly associated with multilocus sequence type ST28 and showed antimicrobial multiresistance profiles. Pulsed-field gel electrophoresis XbaI profiles were highly homogeneous, with only a few minor XbaI profile variants. All strains isolated from reptiles, except one, were strongly associated with ST88, another distantly related type. Most of the strains were susceptible to antimicrobial agents, and XbaI profiles were heterogeneous. Strains isolated from humans yielded seven sequence types (STs) clustering in three distantly related lineages. The first lineage, comprising five STs, represented mainly strains belonging to ST43 and ST149. The other two lineages were represented only by one ST each, ST28 and ST88. The relatedness of strains based on the pathogenicity gene repertoire (102 markers tested) was mostly in agreement with the multilocus sequence type. Because ST28 was frequently isolated from poultry but rarely in humans over the 9-year period investigated, overall, this study indicates that in Germany S. enterica serovar Paratyphi B (dT+) poses a health risk preferentially by contact with reptiles and, to a less extent, by exposure to poultry or poultry meat.

Genotypic and phenotypic differentiation of Salmonella enterica serovar Paratyphi B in Malaysia.

Abstract. Salmonella enterica serovar Paratyphi B is known to cause either paratyphoid fever or gastroenteritis. Differentiation of Salmonella ser. Paratyphi B into biotype Java (d-tartrate fermenting, dT+) and biotype Paratyphi B (d-tartrate non-fermenting, dT) is important for Salmonella epidemiology. This study applied a PCR approach to differentiate the two biotypes to augment the conventional biochemical method and to determine the antibiograms and genomic diversity of Malaysian S. Paratyphi B. Among 100 strains tested (clinical, 86; non-humans, 14), only two clinical strains were confirmed as biotype Paratyphi B as indicated by both lead acetate test and PCR. Antibiotic resistance rates were as follows: streptomycin 18%, sulphonamides 13%, ampicillin 10%, chloramphenicol 4%, tetracycline 3%, cefotaxime 2%, cefpodoxime 2%, ceftazidime 2%, gentamicin 1% and trimethoprim 1%. None showed resistance towards amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, nalidixic acid and trimethoprim-sulphamethoxazole. Seven strains showed multidrug resistance towards 3 or more classes of antimicrobial agents. REP-PCR and PFGE generated 32 and 76 different profiles, respectively. PFGE (D = 0.99) was more discriminative than REP-PCR (D = 0.93) and antimicrobial susceptibility test (D = 0.48) in subtyping the strains. Strains isolated 18 years apart (1982 - 2008) from different localities in Malaysia were clonally related as demonstrated by REP-PCR and PFGE, indicating that these strains were stable and widely distributed. In some clusters, strains isolated from different sources (clinical, food and animal) were grouped together. Thus, biotype Java was the most common biotype of Salmonella ser. Paratyphi B in Malaysia. The PCR approach is highly recommended due to its simplicity, specificity and ease of operation. The level of antimicrobial resistance among Salmonella ser. Paratyphi B remained relatively low in Malaysia but the emergence of resistance to cephalosporins is a cause for concern.

[Molecular biological and phenotypical characterization of human isolates of Salmonella enterica serovar Paratyphi B dT+ or Salmonella java]. / Molekulárno-biologická a fenotypová charakterizácia humánnych izolátov Salmonella enterica serovar Paratyphi B dT+, alebo Salmonella java.

OBJECTIVE: Salmonella Paratyphi B dT+ (or Salmonella Java) is an emerging public health problem. The study objective was to characterize phenotypically and genotypically 13 human isolates from sporadic cases of infection. MATERIAL AND METHODS: Phenotypic characteristics of 13 human isolates were determined by phage typing, disk diffusion method for testing antimicrobial susceptibility to 11 antibiotics and screening for selected virulence markers, i.e bacterial adherence to xylene, motility and biofilm formation. Genotypic characteristics of the study isolates were determined by PCR with primers for the detection of class 1 integrons, plasmid profile analysis and PFGE for the study of genetic diversity. RESULTS: The study isolates were classified into different phage types, with 3aI or 3aI variant being the most common (61.5%). All study isolates were resistant to streptomycin and sulfisoxazole, two of them were multiresistant (to streptomycin, sulfisoxazole, ampicillin and nalidixic acid). The study isolates showed low hydrophobicity, except for one isolate (2/08), and 5 isolates exhibited motility of > or = 50 mm. High biofilm formation was detected in 5 isolates. Class 1 integrons were not detected in any isolate and plasmid profile analysis revealed the presence of a 90-kb plasmid in 8 isolates. XbaI PFGE analysis differentiated the isolates into 6 pulsotypes (X1, X2, X2a, X3, X4,X5). CONCLUSION: Although the study set of S. Paratyphi B dT+ (S. Java) was small, the increasing emergence of this serovar in the human population in Slovakia is noteworthy. The results of gene analysis in PFGE suggest clonal diversity as well as a clonal link between strains of the predominant phage type. In view of possible increase in antimicrobial resistance and the spread of certain clones, continuous surveillance of strains of S. Paratyphi B dT+ is needed.

Characterization of pathogenic and resistant genome repertoire reveals two clonal lines in Salmonella enterica subsp. enterica serovar Paratyphi B (+)-tartrate positive.

A total of 36 contemporary human, animal, and environmental (+)-tartrate-fermenting (dT+) Salmonella enterica serovar Paratyphi B isolates, formerly called Salmonella serovar Java, and five related monophasic S. enterica serovar 4,5,12:b:- isolates from Belgium, Germany, the Netherlands, and the United Kingdom were investigated for clonality and antimicrobial resistance profiles, as well as their virulence and resistance gene repertoire. Two major clonal lines, which could be phenotypically differentiated by the expression of the O:5 antigen, were identified. All O:5 antigen negative strains were multidrug resistant and originated (with two exceptions) from Belgian, Dutch, or German poultry. Strains exhibiting the O:5 antigen encoded by the oafA gene revealed a more heterogeneous group including multidrug-resistant and susceptible strains. Compared to O:5 antigen negative isolates, Salmonella Paratyphi B dT+ O:5 positive strains possessed additional virulence determinants. The Salmonella genomic island 1 was only found in O:5 positive strains. Five monophasic Salmonella 4,5,12:b:- lacking the phase-2 flagellar antigen were assigned to Salmonella Paratyphi B dT+ isolates of the O:5 positive group. The conclusion of the analysis is that Salmonella Paratyphi B dT+ O:5 negative and O:5 positive isolates evolved from a different lineage. Salmonella Paratyphi B dT+ O:5 positive strains possess additional fimbrial and virulence genes that probably enable this clone to interact with a broader range of hosts and the environment. Salmonella Paratyphi B dT+ O:5 negative continuously persists in poultry across Western Europe, especially Belgium, the Netherlands, and Germany.

Isolation of Salmonella enterica subspecies enterica serovar Paratyphi B dT+, or Salmonella Java, from Indonesia and alteration of the d-tartrate fermentation phenotype by disrupting the ORF STM 3356.

Salmonella enterica subspecies enterica serovar Paratyphi B [O1,4,(5),12 : Hb : 1,2] can cause either an enteric fever (paratyphoid fever) or self-limiting gastroenteritis in humans. The d-tartrate non-fermenting variant S. enterica subsp. enterica serovar Paratyphi B dT- (S. Paratyphi B) is the causative agent of paratyphoid fever, and the d-tartrate fermenting variant S. enterica subsp. enterica serovar Paratyphi B dT+ (S. Paratyphi B dT+; formerly called Salmonella Java) causes gastroenteritis. S. Java is currently recognized as an emerging problem worldwide. Twelve dT+ S. Java isolates were collected in Indonesia between 2000 and 2002. One-third of them contained Salmonella genomic island 1 (SGI1), which gives the multidrug-resistant phenotype to the bacteria. In this study, a PCR-based method to detect a single nucleotide difference responsible for the inability to ferment d-tartrate, reported elsewhere, was validated. The d-tartrate fermenting phenotype of S. Java was converted to the non-fermenting phenotype by the disruption of the ORF STM 3356, and the d-tartrate non-fermenting phenotype of the ORF STM 3356-disrupted strain and the dT- reference strain was changed to the dT+ phenotype by complementing ORF STM 3356 in trans. The results show that the dT+ phenotype requires a functional product encoded by STM 3356, and support the use of the PCR-based discrimination method for S. Paratyphi B and S. Java as the standard differentiation method.

Phenotypic and genotypic characterization of Salmonella enterica serotype paratyphi B isolates from environmental and human sources in Galicia, Spain.

Salmonella serotype Paratyphi B isolates obtained from shellfish and human infections in Galicia (northwest Spain) from 1998 were investigated by different phenotypic and genetic methods to evaluate their systemic or enteric nature. Isolates were investigated for D-tartrate fermentation, presence of genes encoding the effector proteins sopE1 and avrA, pulsed-field gel electrophoresis profile, and antimicrobial susceptibility. Systemic variant strains (dT-) were the dominant among the marine environment isolates. All dT- isolates were sopE1 positive and avrA negative, presented an indistinguishable electrophoresis profile, and were grouped in a single cluster. More electrophoresis heterogeneity was observed among dT+ isolates. Only two isolates showed resistance to any of the 16 antibiotics included in our panel. The present study identified the marine environment as a potential natural source of systemic variant isolates of Salmonella Paratyphi B. The presence of systemic variant isolates of Salmonella Paratyphi B in the marine environment is of notable public health significance as a result of the potential risk of acquiring enteric fever linked to the consumption of raw shellfish.

Multiple-antibiotic resistance in Salmonella enterica serotype Paratyphi B isolates collected in France between 2000 and 2003 is due mainly to strains harboring Salmonella genomic islands 1, 1-B, and 1-C.

This study was conducted to investigate the occurrence of multiple-antibiotic resistance among 261 clinical isolates of Salmonella enterica serotype Paratyphi B strains collected between 2000 and 2003 through the network of the French National Reference Center for Salmonella. The 47 multidrug-resistant (MDR) isolates identified (18%), were characterized on the basis of the presence of several resistance genes (bla(TEM), bla(PSE-1), bla(CTX-M), floR, aadA2, qacEdelta1, and sul1), the presence of Salmonella genomic island 1 (SGI1) by PCR mapping and hybridization, and the clonality of these isolates by several molecular (ribotyping, IS200 profiling, and pulsed-field gel electrophoresis [PFGE]) and phage typing methods. The results of PCR and Southern blot experiments indicated that 39 (83%) of the 47 S. enterica serotype Paratyphi B biotype Java MDR isolates possessed the SGI1 cluster (MDR/SGI1). Among these 39 MDR/SGI1 isolates, only 3 contained variations in SGI1, SGI1-B (n = 1) and SGI1-C (n = 2). The 39 MDR/SGI1 isolates showed the same specific PstI-IS200 profile 1, which contained seven copies from 2.6 to 18 kb. Two PstI ribotypes were found in MDR/SGI1 isolates, RP1 (n = 38) and RP6 (n = 1). Ribotype RP1 was also found in two susceptible strains. Analysis by PFGE using XbaI revealed that all the MDR/SGI1 isolates were grouped in two related clusters, with a similarity percentage of 82%. Isolation of MDR/SGI1 isolates in France was observed mainly between the second quarter of 2001 and the end of 2002. The source of the contamination has not been identified to date. A single isolate possessing the extended-spectrum beta-lactamase bla(CTX-M-15) gene was also identified during the study.

Emergence of multidrug-resistant Salmonella Paratyphi B dT+, Canada.

We document an increase in the number of multidrug-resistant Salmonella enterica serovar Paratyphi B dT+ identified in Canada. Most of these strains harbor Salmonella genomic island 1 (SGI1). Further studies are needed to determine factors contributing to the observed emergence of this multidrug-resistant strain.

DNA fingerprinting of human isolates of Salmonella enterica serotype Paratyphi B in Malaysia.

AIMS: DNA fingerprinting of Salmonella enterica serotype Paratyphi B isolated in Malaysia during 1982-83, 1992 and 1996-2002 was carried out by pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility tests and D-tartrate utilization tests to assess the extent of genetic diversity of these isolates in Malaysia. METHODS AND RESULTS: Eighty-six human isolates and one food isolate of Salm. Paratyphi B were analysed by PFGE, antimicrobial susceptibility tests and D-tartrate utilization tests. Sixty-five strains were D-tartrate-negative (dT-) while 22 strains were D-tartrate-positive (dT+). Thirty-seven per cent of the Salm. Paratyphi B strains were resistant to one or more antimicrobial agents. PFGE analysis clearly distinguished the dT- and dT+ strains into two clusters based on the unweighted pair group average method (UPGMA). Twenty-two XbaI-pulsotypes were observed among the 65 dT- strains while 17 XbaI-pulsotypes were observed among the 22 isolates of Salm. Paratyphi B dT+. CONCLUSIONS: The present study showed that PFGE was very discriminative with 33.7% of the strains yielding distinct fingerprints. Paratyphoid fever in Malaysia is probably caused by one predominant, endemic clone of Salm. Paratyphi B dT- with various subtypes. There was no association between the pulsotypes and the severity of the disease indicating that the severity of the disease is probably multifactorial. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of the present study verify the usefulness of PFGE in characterizing strains of Salm. Paratyphi B. This is the first report on the application of PFGE on a large collection of Salm. Paratyphi B in Malaysia.

Molecular properties of Salmonella enterica serotype paratyphi B distinguish between its systemic and its enteric pathovars.

Salmonella enterica serotype O1,4,5,12:Hb:1,2, designated according to the current Kauffmann-White scheme as S. enterica serotype Paratyphi B, is a very diverse serotype with respect to its clinical and microbiological properties. PCR and blot techniques, which identify the presence, polymorphism, and expression of various effector protein genes, help to distinguish between strains with systemic and enteric outcomes of disease. All serotype Paratyphi B strains from systemic infections have been found to be somewhat genetically related with respect to the pattern of their virulence genes sopB, sopD, sopE1, avrA, and sptP as well as other molecular properties (multilocus enzyme electrophoresis type, pulsed-field gel electrophoresis [PFGE] type, ribotype, and IS200 type). They have been classified as members of the systemic pathovar (SPV). All these SPV strains possess a new sopE1-carrying bacteriophage (designated PhiSopE309) with high SopE1 protein expression but lack the commonly occurring avrA determinant. They exhibit normal SopB protein expression but lack SopD protein production. In contrast, strains from enteric infections classified as belonging to the enteric pathovar possess various combinations of the respective virulence genes, PFGE pattern, and ribotypes. We propose that the PCR technique for testing for the presence of the virulence genes sopE1 and avrA be used as a diagnostic tool for identifying both pathovars of S. enterica serotype Paratyphi B. This will be of great public health importance, since strains of serotype Paratyphi B have recently reemerged worldwide.

Explosive increase of Salmonella Java in poultry in the Netherlands: consequences for public health.

In the Netherlands Salmonella Paratyphi B variant Java increased in poultry from less than 2% of all isolates before 1996 to 60% in 2002. Despite exposure to contaminated meat is high, human patients with Java infection are rare (0.3% of all isolates). However, 50% of the human isolates showed PFGE profiles identical to the poultry clone. Resistance to flumequin in S. Java increased from 3% between 1996-2000 to 19% in 2001, and 39% in 2002, while that of other serotypes in poultry remained at about 7%. S. Java is also fast becoming less sensitive to ciprofloxacin.

Investigation of human infections with Salmonella enterica serovar Java in Scotland and possible association with imported poultry.

PFGE analysis of S. Java strains (29 from humans, 30 from poultry meat) showed two major clusters. All isolates from poultry imported from the Netherlands belonged to Cluster A, which also comprised 10 human isolates. Thirty-one of the 37 isolates in this cluster had an identical JavX1 pattern, similar to the X8 profile of a particular S. Java clone predominant in poultry production in several European countries. Cluster B comprised 19 human isolates and two poultry isolates of unknown origin. These results combined with epidemiological data and information on the origins of poultry meat strongly suggested that imported poultry meat is an important source of Java infections in humans in Scotland.

Molecular epidemiological study of Salmonella enterica serovar paratyphi B infections imported from Turkey to Western Norway.

During the summer of 1999, several Norwegian tourists returning from Turkey became ill as a result of Salmonella enterica serovar paratyphi B (S. paratyphi B) infection. We examined the S. paratyphi B isolates from 14 of these patients (10 from blood cultures, 4 from stool specimens) who were admitted to 2 hospitals in Bergen, Norway during August and September 1999. Moreover, during the same period, a laboratory technician working at 1 of these hospitals was admitted with S. paratyphi B septicemia and was included in the study. Using repetitive-sequence-based PCR (rep-PCR) with 2 primer pairs (ERIC and REP), pulsed-field gel electrophoresis and phage typing we found that the laboratory technician was infected with the same S. paratyphi B clone as the 14 tourists. The discriminatory capacity of the rep-PCR method and pulsed-field gel electrophoresis was examined using S. paratyphi B strains from the outbreak and from other geographical locations. We conclude that a combination of rep-PCR with the ERIC primer pair and phage typing was useful in discriminating between the epidemic isolates and epidemiologically unrelated isolates from S. paratyphi B infections and that the laboratory technician was most likely infected while handling patient samples or bacterial cultures from the Turkish tourists.