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Development of a monoclonal antibody to a Ureaplasma urealyticum serotype 9 antigen.

We produced a monoclonal antibody (MAb) to Ureaplasma urealyticum Vancouver, the serotype 9 standard strain. By immunoblotting, this MAb showed a single, 85-kDa band with the homologous serotype and a minor, 100-kDa band with serotype 2 but did not react with any other serotype standard strain. Clinical isolates of U. urealyticum were tested with this MAb and with two sets of polyclonal antisera against the 14 serotype standard strains. The use of MAb 9-2H9 correctly identified certain serotype 9 strains but did not react with wild-type strains lacking the serotype 9 determinant.

Animals↗

Apodemus species mice are reservoir hosts of Borrelia garinii OspA serotype 4 in Switzerland.

Among Borrelia burgdorferi sensu lato isolates, seven outer surface protein A (OspA) serotypes have been described: serotypes 1 and 2 correspond to B. burgdorferi sensu stricto and Borrelia afzelii, respectively, and serotypes 3 to 7 correspond to Borrelia garinii. In Europe, serotype 4 has never been isolated from Ixodes ricinus ticks until recently, although this serotype has been frequently isolated from cerebrospinal fluid from patients. In Europe, B. afzelii and B. burgdorferi sensu stricto were found associated with rodents and B. garinii was found associated with birds. In this study, the reservoir role of Apodemus mice for B. garinii OspA serotype 4 was demonstrated by xenodiagnosis. Apodemus mice are the first identified reservoir hosts for B. garinii OspA serotype 4.

Animals↗

Genetic diversity of clinical and environmental strains of Salmonella enterica serotype Weltevreden isolated in Malaysia.

The incidence of food-borne salmonellosis due to Salmonella enterica serotype Weltevreden is reported to be on the increase in Malaysia. The pulsed-field gel electrophoresis (PFGE) subtyping method was used to assess the extent of genetic diversity and clonality of Salmonella serotype Weltevreden strains from humans and the environment. PFGE of XbaI-digested chromosomal DNA from 95 strains of Salmonella serotype Weltevreden gave 39 distinct profiles with a wide range of Dice coefficients (0.27 to 1.00), indicating that PFGE is very discriminative and that multiple clones of Salmonella serotype Weltevreden exist among clinical and environmental isolates. Strains of one dominant pulsotype (pulsotype X1/X2) appeared to be endemic in this region, as they were consistently recovered from humans with salmonellosis between 1996 and 2001 and from raw vegetables. In addition, the sharing of similar PFGE profiles among isolates from humans, vegetables, and beef provides indirect evidence of the possible transmission of salmonellosis from contaminated raw vegetables and meat to humans. Furthermore, the recurrence of PFGE profile X21 among isolates found in samples of vegetables from one wet market indicated the persistence of this clone. The environment in the wet markets may represent a major source of cross-contamination of vegetables with Salmonella serotype Weltevreden. Antibiotic sensitivity tests showed that the clinical isolates of Salmonella serotype Weltevreden remained drug sensitive but that the vegetable isolates were resistant to at least two antibiotics. To the best of our knowledge, this is the first study to compare clinical and environmental isolates of Salmonella serotype Weltevreden in Malaysia.

DNA, Bacterial↗

Listeria monocytogenes serotype identification by PCR.

Serotyping is a universally accepted subtyping method for Listeria monocytogenes. Identification of the strain serotype permits differentiation between important food-borne strains (1/2a, 1/2b, and 4b) and provides a "gold standard" for comparing isolates analyzed in different labs and with different techniques. Although an efficient enzyme-linked immunosorbent assay serotyping protocol was described recently, identification of PCR serotyping primers would further increase the ease and accessibility of this classification system. Serotyping PCR primers were designed from variable regions of the L. monocytogenes genome. Three primer sets were used in conjunction with a previously described Division III primer set in order to classify 122 L. monocytogenes strains into five serotype groups [1/2a(3a), 1/2b, 1/2c(3c), 4b(d,e), and 4a/c]. Results of the PCR method agreed with those of the conventional slide agglutination method for 97, 100, 94, and 91% of strains belonging to serotypes 1/2a, 1/2b, 1/2c, and 4b, respectively.

Animals↗

Evaluation of methodology for serotyping invasive and nasopharyngeal isolates of Haemophilus influenzae in the ongoing surveillance in Brazil.

To assess the magnitude of discrepant results obtained by routine Haemophilus influenzae serotyping, 258 isolates, collected by the epidemiological surveillance system in Brazil from individuals with invasive diseases or carriage, were evaluated by two slide agglutination (SlAg) methods: SlAg method 1, by which strains were initially screened with a serotype b-specific antiserum, and SlAg method 2, by which strains were tested against all serotype-specific antisera in parallel. Investigators comparing results of the two SlAg methods with those obtained by capsule type-specific PCR were blinded to the method used. The serotype prevalence rates found by the three methods were significantly different, involving discrepancies mainly between serotype b and noncapsulated (NC) isolates. For invasive isolates (n = 131), the overall agreement rate between SlAg method 1 or 2 and PCR was 68.0 or 88.3%, respectively, whereas for colonizing isolates (n = 127) the corresponding rate was 46.5 or 94.2%, respectively. SlAg method 2 improved the ascertainment of serotypes over that obtained with SlAg method 1, demonstrating good correlation with PCR. Use of the polyvalent antiserum as a screening reagent for SlAg for invasive and colonizing isolates showed poor discriminatory power, with a sensitivity of 65.8% and a specificity of 91.7%. We stress the importance of using a well-standardized SlAg methodology and suggest that reference laboratories should utilize PCR routinely to confirm SlAg results and to check all nonspecific SlAg reactions and apparent NC isolates by SlAg in order to provide reliable data on the prevalence of H. influenzae serotypes in the H. influenzae type b vaccine era.

Brazil↗

SHV-12-like extended-spectrum-beta-lactamase-producing strains of Salmonella enterica serotypes Babelsberg and Enteritidis isolated in France among infants adopted from Mali.

From December 2002 to June 2003, 14 cultures of Salmonella enterica serotype Babelsberg and 6 cultures of serotype Enteritidis, isolated in France from internationally adopted children, were identified at the French National Reference Center for Salmonella. All serotype Babelsberg isolates were related, as determined by pulsed-field gel electrophoresis, and all serotype Enteritidis strains displayed the same phage type. All serotype Enteritidis and seven serotype Babelsberg isolates produced an SHV-12-like extended-spectrum beta-lactamase as determined by sequencing of PCR products and by isoelectrofocusing. Some serotype Enteritidis isolates exhibited additional antimicrobial resistance (aminoglycosides, tetracycline, chloramphenicol, sulfonamides, and trimethoprim). Our investigation indicated that these Salmonella isolates were certainly acquired in the same orphanage in Bamako, Mali, before the children were adopted by French families. An inappropriate use of ceftriaxone was probably the cause of the emergence of such strains. There is an urgent need to determine the origin of the contamination and to introduce adequate antibiotic protocols into this orphanage to prevent further transmission and dissemination. Screening for infections and follow-up, adapted to the origin of the internationally adopted children, should be recommended.

Adoption↗

Rapid detection and differentiation of dengue virus serotypes by a real-time reverse transcription-loop-mediated isothermal amplification assay.

The development and validation of a one-step, real-time, and quantitative dengue virus serotype-specific reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay targeting the 3' noncoding region for the rapid detection and differentiation of dengue virus serotypes are reported. The RT-LAMP assay is very simple and rapid, wherein the amplification can be obtained in 30 min under isothermal conditions at 63 degrees C by employing a set of four serotype-specific primer mixtures through real-time monitoring in an inexpensive turbidimeter. The evaluation of the RT-LAMP assay for use for clinical diagnosis with a limited number of patient serum samples, confirmed to be infected with each serotype, revealed a higher sensitivity by picking up 100% samples as positive, whereas 87% and 81% of the samples were positive by reverse transcription-PCR and virus isolation, respectively. The sensitivity and specificity of the RT-LAMP assay for the detection of viral RNA in patient serum samples with reference to virus isolation were 100% and 93%, respectively. The optimal assay conditions with zero background and no cross-reaction with other closely related members of the Flavivirus family (Japanese encephalitis, West Nile, and St. Louis encephalitis viruses) as well as within the four serotypes of dengue virus were established. None of the serum samples from healthy individuals screened in this study showed any cross-reaction with the four dengue virus serotype-specific RT-LAMP assay primers. These findings demonstrate that RT-LAMP assay has the potential clinical application for detection and differentiation of dengue virus serotypes, especially in developing countries.

Dengue↗

Isolation of an atypical strain of Actinobacillus pleuropneumoniae serotype 1 with a truncated lipopolysaccharide outer core and no O-antigen.

A field isolate of Actinobacillus pleuropneumoniae, the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia, was sent to the diagnostic laboratory for serotyping. The isolate presented a clear reaction, with both polyclonal antibodies against serotype 1 and monoclonal antibodies against the capsular polysaccharide of serotype 1. It also exhibited a PCR profile of Apx toxins expected for serotype 1. The isolate, however, failed to react with monoclonal antibodies against the O-antigen of serotype 1 lipopolysaccharide (LPS), suggesting a rough phenotype. The lipid A-core region of the isolate migrated faster than the corresponding region of the serotype 1 reference strain S4074 by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting the presence of a truncated core. Sugar analysis and mass spectrometry analysis of the O-deacylated LPS from the field isolate were consistent with the absence of O-antigen and truncation of the outer core compared to the wild-type reference strain. Experimental infection of pigs confirmed the virulence of the isolate. This is the first report of an isolate of A. pleuropneumoniae serotype 1 with a truncated outer core and a rough LPS phenotype. Veterinary diagnostic laboratories should be vigilant, since infections caused by such an isolate will not be detected by serological tests based on LPS O-antigen.

Actinobacillus Infections↗

Listeria monocytogenes serotype 4b strains belonging to lineages I and III possess distinct molecular features.

A collection of Listeria monocytogenes serotype 4b strains belonging to lineages I and III were examined by PCR and Southern blot analysis using species-, virulence-, and serotype-specific primers and probes. Whereas four serotype 4b lineage I strains reacted in PCR with the serotype 4b-, 4d-, and 4e-specific ORF2110 and virulence-specific lmo1134 and lmo2821 primers, all nine serotype 4b lineage III strains were negative by ORF2110 and lmo1134 primers. In addition, the nine serotype 4b lineage III strains formed two separate groups through their reactions in PCR with virulence-specific lmo2821 primers. Southern blot analysis using species-specific lmo0733 and virulence-specific lmo2821 gene probes largely confirmed the PCR results. These findings indicate that L. monocytogenes serotype 4b strains belonging to lineages I and III possess distinct molecular features.

Animals↗

Pre- and postvaccination clonal compositions of invasive pneumococcal serotypes for isolates collected in the United States in 1999, 2001, and 2002.

Monitoring of serotypes and their clonal associations is critical as pneumococci adapt to the selective pressures exerted by the pneumococcal seven-valent conjugate vaccine (PCV7). We genotyped 1,476 invasive isolates from the Active Bacterial Core surveillance (705 [89.8%] of the isolates were obtained from children <5 years of age, and 771 [18.4%] of the isolates were obtained from individuals >5 years of age) in 2001 and 2002 (after the introduction of PCV7). The data were compared to the results for 1,168 invasive isolates (855 [83.9%] of the isolates were from children <5 years of age) collected in 1999. Among children <5 years of age, the incidence of invasive disease due to non-PCV7 serogroups together with serogroup 19A increased (P < 0.001). Eighty-three clonal sets, representing 177 multilocus sequence types (STs), were compiled from the 3-year isolate set. Among the non-PCV7 serogroups, newly emerging clones were uncommon; and a significant expansion of already established clones occurred for serotypes 3 (ST180), 7F (ST191), 15BCF (ST199), 19A (ST199), 22F (ST433), 33F (ST662), and 38 (ST393). However, additional minor clonal types within serotypes 1, 6A, 6B, 7C, 9N, 10A, 12F, 14, 15B/C, 17F, 19A, 19F, 20, 22F, and 33F that were absent in 1999 were found during 2001 and 2002. Although 23 clonal sets exhibited multiple serotypes, for most serotypes there were either no changes or modest changes in clonal compositions since the introduction of PCV7. The only example of an identical ST shared between non-PCV7 and PCV7 or PCV7-related serotypes was ST199; however, ST199 was prevalent within serotypes 15B/C and 19A before and after PCV7 introduction. Continued genotypic surveillance is warranted, since certain clones not targeted by PCV7 are expanding, and their emergence as significant pathogens could occur with maintained vaccine pressure.

Adult↗

Use of a serotype-specific DNA microarray for identification of group B Streptococcus (Streptococcus agalactiae).

Group B Streptococcus (GBS; Streptococcus agalactiae) is an important cause of sepsis and meningitis. Nine GBS serotypes, based on capsular polysaccharide (CPS) antigens, have been described. Their distribution varies worldwide and needs to be monitored to understand the epidemiology of GBS disease and inform the development of vaccines. In this study, we sequenced cpsH of GBS serotype II (cpsHII) and compared it with that of the other eight serotypes to identify serotype-specific regions. We then developed a DNA microarray based on the cpsH gene and used it to test 88 GBS isolates-9 serotype reference strains and 79 clinical isolates-and 7 other bacterial and fungal species which are commonly present in the vagina flora. The microarray was shown to be specific and reproducible. This is the first report of a microarray which can identify the nine GBS serotypes. The use of a microarray has advantages over traditional serotyping methods and will be of practical value in both reference and diagnostic laboratories.

Bacterial Capsules↗

Demonstration of dual rhinovirus infection in humans by isolation of different serotypes in human heteroploid (HeLa) and human diploid fibroblast cell cultures.

The ability to isolate rhinoviruses in human heteroploid cell cultures was investigated by inoculating HeLa cells (HeLa M) with specimens previously shown to be positive in human diploid cell cultures. The 135 positive specimens selected were representative of 22 different rhinovirus types, and 4 to 9 specimens were available for each serotype. Specimens were inoculated into human diploid fetal tonsil fibroblasts (FT), HeLa cells with 30 mM Mg2+, and HeLa cells without increased Mg2+. One hundred twelve rhinovirus strains (83%) were reisolated in FT cells, whereas 76 rhinovirus strains (56%) were recovered in HeLa cells with 30 mM Mg2+. All strains recovered in FT were the same serotype as that originally recovered in diploid cells, but five of the HeLa cell isolates (3.7% of total specimens) were different serotypes, indicating dual rhinovirus infections. Four rhinovirus serotypes, (3, 42, 48, and 70) were recovered in HeLa but not in diploid cells; these serotypes were rare in our previous studies. Isolation of rhinovirus in FT cells was usually accomplished at first passage, whereas rhinovirus cytopathic effects in HeLa cells were not observed at first passage, but required one, two, or (rarely) three blind passages. Only 28 rhinoviruses (21%) were recovered in HeLa cells without increased Mg2+; however, three serotypes, types 16, 36, and 58, were recovered as effectively in HeLa cells, with or without added Mg2+, as they were in FT cells. In general, rhinoviruses were less efficiently recovered in HeLa cells; however, certain serotypes may be detected better by HeLa cells.

Cell Line↗

In vitro RNA transcription by the New Jersey serotype of vesicular stomatitis virus. I. Characterization of the mRNA species.

The in vitro RNA synthesis by the virion-associated RNA polymerase of vesicular stomatitis virus (VSV), New Jersey serotype, was compared with that of the serologically distinct Indiana serotype of VSV. The New Jersey serotype of VSV synthesized five distinct mRNA species in vitro, three of which were smaller than the corresponding species synthesized by the Indiana serotype of VSV. These included the mRNA's coding for the G, M, and NS proteins. By hybridization experiments, virtually no sequence homology was detected between the mRNA's of the two serotypes. Despite this lack of overall homology, the 12 to 18S mRNA species of both serotype contained a common 5'-terminal hexanucleotide sequence, G(5')ppp(5')A-A-C-A-G. The signicance of this finding in light of specific interactions between the two serotypes of VSV in vivo is discussed.

Base Sequence↗

Comparison of the major antigenic determinants of different serotypes of foot-and-mouth disease virus.

Complete nucleotide sequences which code for the capsid protein VP1 of two foot-and-mouth disease virus serotypes, O1Campos/Brazil/58 and C3Indaial/Brazil/71, have been determined. Ten available VP1 sequences (three serotype O, three serotype C, and four serotype A) were aligned and compared. Our evidence suggests that O1BFS/Britain/68 and O1K/Germany/66 are closely related to O1Campos/Brazil/58. Significant variations were observed between the nucleotide sequences of C3Indaial determined by two different laboratories. These differences are probably the result of virus adaptation and propagation in different laboratories. In one of the isolates (C3Biogen), a 13-base-pair stem and 13-base-pair loop structure is located in the 134-158 amino acid variable region. Isolates of different serotypes differ at two highly variable regions, amino acid positions 42-60 and 134-158, but isolates of the same serotype show major differences only in the variable region between amino acids 134 and 158. Since the remaining amino acid sequence of VP1 is highly conserved, we conclude that the 134-158 amino acid variable region is involved in subtype specificity, whereas both variable regions contribute to serotype differences.

Amino Acid Sequence↗

Frequency of Candida albicans serotypes in patients with denture-induced stomatitis and in normal denture wearers.

A comparison has been made between the serotypes of oral Candida albicans taken from patients with denture-induced stomatitis and from a group of age and sex-matched controls. C albicans isolates were obtained from the fitting surface of the denture, the palatal mucosa supporting the denture, and the buccal mucosa. Twenty-nine of the 30 patients samples in the group affected by denture-induced stomatitis had only C albicans serotype A on their palatal mucosa and denture surface, while mixtures of serotypes were obtained from the buccal mucosa of these patients. Only one patient had serotype B isolates from the palatal mucosa and denture surface. In contrast, the control group had mixture of A and B serotypes from both the denture surface and the palatal mucosa, as well as from the buccal sites sampled. It would appear from these results that denture-induced stomatitis is associated with the proliferation of a single C albicans serotype, usually serotype A.

Candidiasis, Oral↗

Serotyping of Mannheimia (Pasteurella) haemolytica isolates from the upper Midwest United States.

Mannheimia (Pasteurella) haemolytica biotype A serotype1 (A1) is the primary bacterial agent responsible for the clinical signs and pathophysiologic events in bovine pneumonic pasteurellosis. The goal of this study was to determine the prevalence of other serotypes of M. haemolytica biotype A organisms obtained from the upper Midwest diagnostic laboratories. A total of 147 M. haemolytica isolates were collected from Minnesota, South Dakota, and Michigan. Isolates were tested against M. haemolytica antisera obtained from the National Animal Disease Center, Ames, Iowa. Results indicated that M. haemolytica serotype 1 represented approximately 60%, serotype 6 represented 26%, and serotype 2 represented 7% of the total examined isolates. In addition, 7% of the isolates were serotype 9, 11, or untypable. This finding suggests that M. haemolytica serotypes other than serotype 1 can be isolated from the lung lesions of diseased cattle and seem to be capable of causing the pathologic changes observed in the lung with pneumonic pasteurellosis.

Animals↗

The molecular epidemiology of foot-and-mouth disease virus serotypes A and O from 1998 to 2004 in Turkey.

BACKGROUND: Foot-and-Mouth Disease (FMD) causes significant economic losses in Turkish livestock. We have analysed the genetic diversity of the 1D sequences, encoding the hypervariable surface protein VP1, of Turkish isolates of serotype A and O collected from 1998 to 2004 in order to obtain epidemiological and immunological information. RESULTS: The 1D coding region of 33 serotype O and 20 serotype A isolates, obtained from outbreaks of FMD between 1998 and 2004, was sequenced. For serotype A, we confirmed the occurrence of the two subtypes IRN99 and IRN96. These subtypes are most divergent within the region encoding the immuno-dominant GH-loop. Also a close relationship to Foot-and-Mouth Disease virus (FMDV) serotype A isolates obtained from outbreaks in Iraq and Iran were detected and a clustering of isolates collected during the same period of time were found. The analysis of the deduced amino-acid sequences of these subtypes revealed evidence of positive selection in one site and one deletion, both within the GH-loop region. By inferring the ancestral history of the positively selected codon, two potential precursors were found. Furthermore, the structural alignment of IRN99 and IRN96 revealed differences between the tertiary structures of these subtypes. The similarity plot of the serotype O isolates suggested a more homogeneous group than the serotype A isolates. However, phylogenetic analysis revealed two major groups, each further divided in subgroups, of which some only consisted of Turkish isolates. Positively selected sites and structural differences of the Turkish isolates analysed, were not found. CONCLUSION: The sequence and structural analysis of the IRN99 strains is indicative of positive selection suggesting an immunological advantage compared to IRN96. However, results of antigenic comparison reported elsewhere do not substantiate such a conclusion. There is evidence that IRN99 was introduced to Turkey, in all probability from Iran. Since, a member of the IRN96 lineage was included as a component of the FMDV vaccine produced since 2000, the outbreaks caused by IRN96 strains in 2004 could be due to incomplete vaccine coverage. The Turkish type O strains, all with a VP1 structure similar to the O1/Manisa/69 vaccine, appear in several sublineages. Whether these sublineages reflect multiple samplings from a limited number of outbreaks, or if they reflect cross-boundary introductions is not clear.

Amino Acid Sequence↗

[Utility of AAV vectors derived from novel serotypes].

AAV vector is derived from nonpathogenic virus and has a number of attractive features as a vector for human gene transfer including safety, broad tissue specificity, and low immunogenicity following gene transfer. Moreover, persistent transgene expression (for years) was demonstrated in multiple animal experiments. For these reasons, applications to a wide spectrum of diseases are expected, and several clinical trials have been conducted. Although it is too early to conclude the outcome, the efficacy of treatment was not sufficiently substantiated in most of the trials despite confirming the safety of the vector. These results are primarily due to low levels of transgene expression. One of the approaches to improve this situation is the use of alternative serotypes of AAV. Traditionally, serotype 2 was considered to be a prototype of AAV, and the majority of studies including human clinical trials have been conducted using this serotype. On the other hand, there are five "classical" serotypes, and several have been additionally discovered from tissues of primates including humans. These serotypes are considered to be valuable resources for vector development to overcome the shortcomings of serotype 2. This review focuses on the difference in expression levels and tissue specificity of various serotype-derived vectors and summarizes current status in the treatment of candidate diseases.

Animals↗