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Serotypes of red clover necrotic mosaic virus. III. Immunoelectrophoresis under different conditions.

The effects of 4 buffers at different pH and of different molarities was tested on the immunoelectrophoresis of representatives of three serotypes and their natural mixtures of red clover necrotic mosaic virus (RCNMV). No substantial differences were observed with buffers at pH 7.2, 8.0 and 8.6. The representatives of the three RCNMV serotypes showed different mobilities in 0.1 and 0.01 mol/l ionic buffers in the agarose gel from cathode to anode. In nonionic 0.01-0.1 mol/l N-2-hydroxyethylpiperazine-N'-ethanesulphonic acid (HEPES) buffer, the RCNMV isolates moved from the anode to the cathode. Isolate TpM48 (serotype B) moved the most rapidly, while isolates No. 6 (serotype C) and TpM34 (serotype A) showed lower mobilities distinct from one another. This made possible a reliable differentiation of serotype B from serotypes A and C as well as of serotype A from serotype C. Agarose gels in 0.001 mol/l buffers proved to be unsuitable for the immunoelectrophoresis of RCNMV.

Hydrogen-Ion Concentration↗

Serotypes of Pasteurella anatipestifer isolated from commercial White Pekin ducks in the United States.

Pasteurella anatipestifer isolates from commercially raised, clinically diseased White Pekin ducks were serotyped by agglutination and agar-gel precipitin methods. Plate agglutination was found to be the most suitable test for preliminary classification. Based on National Animal Disease Center (Ames, Iowa) nomenclature, six serotypes were classified as types 1, 2, 3, 5, 7, and 8. These were compared with strains held by Houghton Poultry Research Station (Houghton, Huntingdon, England), at present constituting 15 serotypes (A to O), isolated in England and other countries. Serotype 1 was found to be identical to serotype A, the strain most commonly associated with outbreaks of the disease in England. Serotype 3 was found to be identical to serotype L, which was isolated from an outbreak of the disease in swans in Tasmania. Types 5, 7, and 8 did not react with any of the typing sera available, but serotype 7 was found to be identical to a strain (type N) isolated subsequently in England. More than 95% of field isolations made from 1975 to 1979 belonged to serotypes 1, 2, and 5.

Agglutination Tests↗

Assay of neutralizing antibodies to animal rotavirus strains and human rotavirus serotype G8 by a modified method in the residents of Pune, India.

In the western literature, four G serotypes (G1-G4) of human rotaviruses have been found to be of a major epidemiological importance. During the analysis of rotavirus serotypes from faecal samples in Pune, over 50% of specimens could not be serotyped with the available monoclonal antibodies against G1-G4 serotypes. The results prompted to look for the prevalence of neutralizing antibodies against serotypes other than the major human serotypes (G1-G4) in adults. Neutralizing antibodies against animal rotavirus serotype, viz. G3, G6 and G10, and human rotavirus serotype G8 were determined in adult sera, by a modified technique, which is ELISA-based and mechanized. The results showed that, of the 68 sera tested at 1:100 dilution, 65 (95.58%) were reactive for G3 (SA-11), 52 (76.47%) for G6 (Bovine Lincoln), 6 (8.82%) for G10 (B223), and 40 (58.82%) for G8 (M69) serotypes. It appears that the prevalence of rotaviruses in India may be quite different from that in the developed countries.

Adult↗

A characterization of monoclonal antibodies prepared against Pasteurella haemolytica serotype 1 surface antigens.

The production and characterization of monoclonal antibodies against Pasteurella haemolytica serotype 1 is described. Ten monoclonal antibodies were produced and divided, on the basis of their properties, into six different groups. One produced bacteria agglutination only of P. haemolytica serotype 1. Three antibodies bound with P. haemolytica serotypes 1, 5-8 and 12 and the antigen was identified in immunoblots as lipopolysaccharide. Two antibodies bound P. haemolytica serotypes 1, 2, 5-8 and 12 and P. multocida serotypes 1-7, 9, 12, 15 and 16, recognizing an epitope present on a 29 kDa outer membrane protein. One antibody bound all P. haemolytica and P. multocida serotypes. The antigen was a hexosamine less than 30 kDa which contained a formalin sensitive epitope. One antibody bound only to P. haemolytica serotype 1 and the antigen was identified as a 66 kDa outer membrane protein. Two antibodies bound P. haemolytica serotypes 1, 2, 5-9 and 12 and the antigen, while not identified, was localized on the outer membrane. This study identified antigens which contribute to the cross-reactions among P. haemolytica and P. multocida serotypes and the antibodies may be useful in investigating the pathogenesis of pneumonic pasteurellosis.

Animals↗

Production and characterization of monoclonal antibodies against Actinobacillus pleuropneumoniae serotype 1.

Three monoclonal antibodies (mAbs) against Actinobacillus pleuropneumoniae serotype 1, designated 4.2 A11 B5, 5.1 G8 F10 and 1.5 C5 F4 (IgG3, IgG2b and IgM respectively), were produced and characterized. mAbs 4.2 A11 B5 and 5.1 G8 F10 were directed against different epitopes located in the O chain of the LPS. Both clones also recognized reference strains of A. pleuropneumoniae serotypes 9 and 11. The mAb 1.5 C5 F4 reacted with the reference strain of A. pleuropneumoniae serotype 1, with the encapsulated strain 4045 (but not with its non-capsulated mutant) and with A. pleuropneumoniae serotype 1 purified capsular polysaccharides (CPS). The epitope was sensitive to periodate oxidation, heat-labile, and located in the capsular material of A. pleuropneumoniae serotype 1, as demonstrated by immunoblotting. Treatment of the CPS with 5% ammonium hydroxide eliminated the reaction, which may indicate that the epitope recognized by 1.5 C5 F4 mAb is a O-acetyl containing determinant. When different A. pleuropneumoniae field strains were tested, the percentage of strains recognized by the mAbs varied with the mAb and the test used. Cross-reactions associated with the LPS of some A. pleuropneumoniae serotype 5 field strains could be observed with the 4.2 A11 B5 mAb. Of the three mAbs characterized, 1.5 C5 F4 seemed to be the most suitable for A. pleuropneumoniae serotype 1 detection since it reacted with 99% of serotype 1 field strains and it did not recognize any of the strains belonging to other serotypes.

Actinobacillus pleuropneumoniae↗

Recombinant vesicular stomatitis (Indiana) virus expressing New Jersey and Indiana glycoproteins induces neutralizing antibodies to each serotype in swine, a natural host.

Vesicular stomatitis virus (VSV) is the most common cause of vesicular disease outbreaks in livestock throughout the Western Hemisphere. Two major serotypes, Indiana and New Jersey, cause epidemic disease in pigs, cattle, and horses. We generated recombinant viruses derived from the Indiana serotype genome that were engineered to contain and express: (1) a single copy of the glycoprotein gene from the Indiana serotype (VSIV-GI); (2) a single copy of the glycoprotein gene from the New Jersey serotype (VSIV-GNJ); or (3) two copies of the glycoprotein gene, one from each of the two major VSV serotypes (VSIV-GNJGI) [Martinez I, Rodriguez LL, Jimenez C, Pauszek SJ, Wertz GW. Vesicular stomatitis virus glycoprotein is a determinant of pathogenesis in swine, a natural host. J Virol 2003;77(14):8039-47]. These recombinant viruses and a highly pathogenic New Jersey field isolate (VSNJV), from which the GNJ gene was derived, were inoculated into swine, a natural host, and the induction of neutralizing antibodies to both serotypes was analyzed. The neutralizing antibody response induced by VSIV-GI, VSIV-GNJ and VSNJV was serotype-specific, according to the glycoprotein expressed. VSIV-GNJGI expressed both glycoproteins stably through multiple rounds of replication in swine and induced neutralizing antibodies against both VSV serotypes, with a dominance of the Indiana serotype in the serological response. Pigs immunized with VSIV-GI or VSIV-GNJ were protected against homologous high dose virus challenge. Pigs inoculated with VSIV-GNJGI were protected against challenge with VSIV-GI but three of four animals developed lesions after challenge with the highly pathogenic New Jersey field isolate.

Animals↗

The emergence in Taiwan of fluoroquinolone resistance in Salmonella enterica serotype choleraesuis.

BACKGROUND: Salmonella enterica serotype choleraesuis is a cause of serious systemic infections. Because fluoroquinolones are the drug of choice for the treatment of severe salmonella infections, the emergence and dissemination of fluoroquinolone-resistant S. enterica serotype choleraesuis have clinical consequences. METHODS: In Taiwan, a hospital-based surveillance system has been in place since 1987 to monitor the incidence of S. enterica serotype choleraesuis infections and the antimicrobial susceptibility of the isolates. We investigated the rapid emergence of fluoroquinolone resistance in this serotype in 2000 and 2001. Pigs in Taiwan were evaluated as a potential source of the resistant salmonella. RESULTS: A total of 501 clinical isolates of S. enterica serotype choleraesuis were recovered in our hospital from 1987 through 2000. The proportion of total salmonella isolates made up by S. enterica serotype choleraesuis decreased from an average of 8.4 percent before 1995 to 2.7 percent in 1996 through 1998. During 1999 and 2000, this proportion increased significantly, to an average of 5.0 percent. Ciprofloxacin resistance in S. enterica serotype choleraesuis has been observed since 2000. In the third quarter of 2001, 60 percent of isolates were resistant to ciprofloxacin. Molecular typing indicated that the primary source of S. enterica serotype choleraesuis isolates was herds of swine. All the resistant isolates from humans and swine had mutations that led to the substitution of phenylalanine for serine at position 83 and asparagine for aspartic acid at position 87 in the gene for DNA gyrase A. CONCLUSIONS: This investigation in Taiwan indicates that fluoroquinolone-resistant S. enterica serotype choleraesuis can spread from swine to humans. The use of fluoroquinolones in food animals should be prohibited.

Animals↗

Site-specific disease potential of individual Streptococcus pneumoniae serotypes in pediatric invasive disease, acute otitis media and acute conjunctivitis.

BACKGROUND: Recent studies have shown that some Streptococcus pneumoniae serotypes possess a higher potential to cause invasive disease than others. However, it is unknown whether disease potential for specific serotypes is similar for mucosal disease. Our objective was to assess the disease potential of individual S. pneumoniae serotypes causing invasive pneumococcal disease (IPD), acute otitis media (AOM) and acute conjunctivitis (AC) in children. METHODS: Serotypes of pneumococcal isolates from children with IPD, AOM and AC were compared with those carried by healthy children aged <3 years. All children resided in the same area and were studied during the same period. Odds ratios for disease were calculated for each diagnosis following multivariate analysis, including gender, age, ethnic group, previous antibiotic treatment and year variability. RESULTS: A total of 5,500 isolates were collected: 189 from blood or cerebrospinal fluid, 3,200 from middle ear fluid, 348 from conjunctiva and 1,763 from nasopharynx of healthy children. A significant positive association with IPD was demonstrated for serotypes 1, 5 and 12F; with AOM for serotypes 1, 3, 5, 12F, 19A and 19F; and with AC for serotype 3 and nontypeable S. pneumoniae. A significant negative association with IPD was demonstrated for nontypeable S. pneumoniae and with AOM for serotypes 6A, 6B, 15A and nontypeable S. pneumoniae. CONCLUSIONS: Our results reflect the importance of the polysaccharide capsule in site-specific disease potential and provide useful information regarding disease potential of nonvaccine serotypes shown to be involved in carriage replacement after vaccination with the 7-valent conjugate vaccine.

Acute Disease↗

Elevated serum IgG titer and avidity to Actinobacillus actinomycetemcomitans serotype c in Japanese periodontitis patients.

AIM: The purpose of this study was to characterize serum antibody responses to different serotypes of Actinobacillus actinomycetemcomitans strains in various forms of periodontitis and to determine whether any specific type of A. actinomycetemcomitans was associated with any specific form of periodontitis in a Japanese population. METHODS: Sonicated whole cell and autoclaved serotype antigens of A. actinomycetemcomitans were used. Serum IgG titer and avidity to A. actinomycetemcomitans were measured by enzyme-linked immunoabsorbant assay (ELISA) and ammonium thiocyanate-dissociation ELISA, respectively, in 46 aggressive periodontitis patients (8 localized, 38 generalized), 28 chronic periodontitis patients, and 18 periodontally healthy subjects. The presence of A. actinomycetemcomitans in plaque and saliva samples was determined using polymerase chain reaction. RESULTS: Generalized aggressive and chronic periodontitis patients exhibited significantly higher IgG titers than healthy subjects to both sonicated and autoclaved antigens of serotype c strains, while IgG titer to serotype b (Y4) was significantly higher in localized aggressive periodontitis patients compared to healthy subjects. No A. actinomycetemcomitans was detected in localized aggressive periodontitis patients. A. actinomycetemcomitans-positive patients exhibited significantly higher IgG titer and avidity to serotype c than A. actinomycetemcomitans-negative patients. In A. actinomycetemcomitans-positive patients, a significantly positive correlation was observed between antibody titer and avidity to serotype c. A. actinomycetemcomitans-positive patients with generalized aggressive periodontitis showed lower IgG avidities to serotype c than those with chronic periodontitis, though no statistically significant difference was found. CONCLUSION: A. actinomycetemcomitans serotype c may play a significant role in chronic and generalized aggressive periodontitis, while A. actinomycetemcomitans serotype b may be associated with localized aggressive periodontitis in a Japanese population.

Actinobacillus Infections↗

Genomic distribution of a serotype 1-specific antigen-coding DNA fragment of Pasteurella haemolytica.

A genomic fragment of Pasteurella haemolytica biotype A coding for a serotype 1-specific agglutinating antigen was used as a probe in a series of hybridization experiments to determine distribution of the fragment in various P. haemolytica serotypes as well as other bacteria. Results showed presence of the fragment in seven out of the 12 serotypes tested, all of which belonged to biotype A. Two other serotypes belonging to biotype A, all three serotypes belonging to biotype T, two Pasteurella multocida isolates and Escherichia coli did not have the fragment in their genome. Thus the expression of the P. haemolytica biotype A serotype 1-specific agglutinating antigen (PHA1SAA) seems to be due to serotype-specific regulation of protein expression rather than to genetic deletion. Differences in methylation of the PHA1SAA-coding fragment was also noted in DpnI and Sau3AI genomic DNA digests from the various serotypes analyzed by Southern blot. However, no apparent correlation was observed between methylation and PHA1SAA expression. E. coli with a recombinant plasmid containing a homologous genomic fragment derived from P. haemolytica serotype 2 also expressed PHA1SAA.

Animals↗

Assignment of weight-based antibody units for 13 serotypes to a human antipneumococcal standard reference serum, lot 89-S(f).

Weight-based immunoglobulin G (IgG), IgM, IgA, and total Ig antibody assignments were made to human antipneumococcal standard reference serum lot 89-S, also known as lot 89-SF, for Streptococcus pneumoniae capsular polysaccharide (PnPs) serotypes 2, 6A, 8, 9N, 10A, 11A, 12F, 15B, 19A, 17F, 20, 22F, and 33F, as well as for C-polysaccharide (C-Ps), extending the standard's usefulness for pneumococcal vaccine evaluation beyond the original serotype 1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F assignments (S. A. Quataert, C. S. Kirch, L. J. Quackenbush Wiedl, D. C. Phipps, S. Strohmeyer, C. O. Cimino, J. Skuse, and D. V. Madore, Clin. Diagn. Lab. Immunol. 2:590-597, 1995). The additional 14 assignments were determined using an equivalence of absorbance method with an anti-PnPs serotype 6B reference enzyme-linked immunosorbent assay (EIA). To assure accuracy, anti-PnPs EIA for serotype 14 antibodies, a previously assigned serotype, was performed concurrently. This method assures consistency of the new microgram-per-microliter assignments with previous antiserotype assignments to lot 89-S. The sum of the experimentally derived isotype assignments for anti-PnPs serotypes in lot 89-S agrees well with the separately determined total Ig assignment for each serotype. The lot 89-S assignments for serotypes 1, 5, 6B, 14, 18C, 19F, and 23F were used for pneumococcal conjugate vaccine clinical trial evaluation and to generate data in efficacy trials where serological correlates for protection have been proposed. The assignment of antibody concentrations to additional pneumococcal serotypes in this reference reagent facilitates the consistent and accurate comparison of serum antibody concentrations across clinical trials.

Antibodies, Bacterial↗

Evidence that the serotype b antigenic determinant of Actinobacillus actinomycetemcomitans Y4 resides in the polysaccharide moiety of lipopolysaccharide.

A high-molecular-weight polysaccharide-containing antigen was isolated from a phenol-water extract of Actinobacillus actinomycetemcomitans ATCC 43718 (formerly Y4) by gel permeation chromatography in lipopolysaccharide (LPS)-disaggregating buffer. The polysaccharide antigen formed a precipitin band with rabbit serotype b-specific antiserum but not with rabbit antisera to serotype a or c. Electroblotted serotype b antigen was probed with serum from a patient with localized juvenile periodontitis (LJP), resulting in a diffuse "smear" in the upper region of the lane. By utilizing an enzyme-linked immunosorbent assay, it was demonstrated that the geometric mean immunoglobulin G antibody titer to the serotype b polysaccharide was significantly higher in sera from LJP patients than in sera from periodontally healthy individuals. Moreover, LJP antibody titers to the serotype b polysaccharide exhibited age-dependent variation. Double immunodiffusion analysis revealed that the serotype b antigen formed a line of identity with low-molecular-weight LPS following reaction with serotype b-specific antiserum. Incubation of LJP serum in the presence of a lipid-free polysaccharide moiety obtained by mild acid hydrolysis of LPS from A. actinomycetemcomitans Y4 markedly reduced immunoglobulin G titer to the serotype b antigen. In contrast, solubilized lipid A was only weakly inhibitory. The results of this study indicate that the serotype b-specific determinant of A. actinomycetemcomitans resides in the polysaccharide moiety of LPS and represents a major target for immunoglobulin G antibody in serum of LJP subjects colonized by this organism.

Actinobacillus↗

The Vi capsular antigen of Salmonella enterica serotype Typhi reduces Toll-like receptor-dependent interleukin-8 expression in the intestinal mucosa.

Human infections with nontyphoidal Salmonella serotypes, such as S. enterica serotype Typhimurium, are characterized by a massive neutrophil influx in the colon and terminal ileum. In contrast, neutrophils are scarce in intestinal infiltrates of typhoid fever patients. Here, we show that in S. enterica serotype Typhi, the causative agent of typhoid fever, expression of the Vi capsular antigen reduced expression of the neutrophil chemoattractant interleukin-8 (IL-8) in host cells. Capsulated bacteria elicited IL-8 expression in polarized human epithelial cells (T84) and human macrophage-like cells (THP-1) in vitro at significantly reduced levels compared to noncapsulated bacteria. Experiments with a human cell line (HEK293) transfected with human Toll-like receptors (TLRs) demonstrated that in the presence of TLR5 or TLR4/MD2/CD14, a noncapsulated serotype Typhi mutant was able to induce the expression of IL-8, while this host response was significantly reduced when cells were infected with the capsulated serotype Typhi wild type. The relevance of these in vitro observations for the interaction of serotype Typhi with its human host was further studied ex vivo using human colonic tissue explants. Expression of IL-8 was detected in human colonic tissue explants infected with serotype Typhimurium or a noncapsulated serotype Typhi mutant. In contrast, infection with the serotype Typhi wild type did not elicit IL-8 expression in colonic tissue explants. Collectively, these data suggest that the scarcity of neutrophils in intestinal infiltrates of typhoid fever patients is due to a capsule-mediated reduction of TLR-dependent IL-8 production in the intestinal mucosa.

Antigens, Bacterial↗

Nucleotide sequence of a cDNA clone encoding the entire glycoprotein from the New Jersey serotype of vesicular stomatitis virus.

The nucleotide sequence of the mRNA encoding the glycoprotein from the New Jersey serotype of vesicular stomatitis virus (VSV) was determined from a cDNA clone containing the entire coding region. The sequence of 12 5'-terminal noncoding nucleotides present in the mRNA but not in the cDNA clone was determined from a primer extended to the 5' terminus of the mRNA. The mRNA is 1,573 nucleotides long (excluding polyadenylic acid) and encodes a protein of 517 amino acids. Only six nucleotides occur between the translation termination codon and the polyadenylic acid. Short homologies between the untranslated termini of this mRNA and the mRNAs of the Indiana serotype were found. The predicted protein sequence was compared with that of the glycoprotein of the Indiana serotype of VSV and with the glycoprotein of rabies virus, using a computer program which determines optimal alignment. An amino acid identity of 50.9% was found for the two VSV serotypes. Approximately 20% identity was found between the rabies virus and VSV New Jersey glycoproteins. The positions and sizes of the transmembrane domains, the signal sequences, and the glycosylation sites are identical in both VSV serotypes. Two of five serine residues which were possible esterification sites for palmitate in the glycoprotein from the Indiana serotype are changed to glycine residues in the glycoprotein from the New Jersey serotype. Because the glycoprotein of the New Jersey serotype does not contain esterified palmitate, we suggest that one or both of these residues are the probable esterification sites in the glycoprotein from the Indiana serotype.

Base Sequence↗

Actinobacillus actinomycetemcomitans serotype-specific genotypes and periodontal status in Brazilian subjects.

Periodontitis is associated with members of the oral microbiota, such as Actinobacillus actinomycetemcomitans. To our knowledge, this is the first study to evaluate, by PCR, the occurrence of the six known bacterium serotypes that included subjects with and without periodontitis. Our group comprised 49 Brazilian subjects. We studied 146 bacterial isolates from 23 patients with aggressive or chronic periodontitis and 26 subgingival specimens from subjects with or without periodontitis, all originating in our collection. Serotypes b and c were observed in similar frequencies, and no subject harboured d, e, or f serotype strains. Around 78% subjects had single-serotype infection. Mixed infection was seen only in aggressive periodontitis patients. An association between serotype b and healthy periodontium and between serotype c and chronic periodontitis was observed. Our results diverge from those previously reported, which may be explained by specific distribution patterns in distinct populations. The association of different serotypes with the same periodontal status or conversely of a serotype with different periodontal conditions indicates that organism serotyping should not be used as a sole reliable marker for predicting the outcome of the infection. Evaluation of factors involved in human oral cavity colonization by subsets of A. actinomycetemcomitans is essential for elucidating organism-host-environment relationships.

Adolescent↗

Comparison of Streptococcus pneumoniae serotypes causing acute otitis media & invasive disease in young children in the Czech Republic.

BACKGROUND & OBJECTIVES: The availability of a type-specific pneumococcal vaccine for children is a worldwide problem. It is necessary to study the serotypes prevalent in a country before introducing a type-specific vaccine. The objective of the present study was to analyse the prevalence of Streptococcus pneumoniae serotypes in children suffering from acute otitis media or invasive pneumococcal disease and to compare a coverage of serotypes by individual pneumococcal vaccines. METHODS: Children suffering from acute otitis media and invasive pneumococcal disease were analysed in the Czech Republic from October 1999 to November 2000. Serotyping was performed by the quellung technique using antisera from Statens Serum Institute (Denmark). RESULTS: The most frequent serotypes in patients with acute otitis media were 3, 19F, 23F, 14, 9V, 1, 6B, 11A and 28F. Vaccine coverage for the identified serotypes in acute otitis media patients was 52.1 per cent for the 7-valent vaccine, 57.8 per cent for the 9-valent vaccine and 75.7 per cent for the 11-valent form of the vaccine. In 108 patients with invasive pneumococcal disease, the most frequent serotypes were 6B, 9V, 14, 19F, 3 and 23F. Vaccine coverage for the identified serotypes in patients with invasive pneumococcal disease was 62 per cent for the 7-valent vaccine, 66.4 per cent for the 9-valent vaccine and 77.5 per cent for the 11-valent form of the vaccine. INTERPRETATION & CONCLUSION: Vaccine coverage for the identified serotypes for the 11-valent pneumococcal vaccine was better than the other two vaccines.

Acute Disease↗

Serotypes and antimicrobial resistance of Campylobacter jejuni isolated from humans and animals in Thailand.

We investigated the serotypes, distributions, and antimicrobial resistance of Campylobacter jejuni isolates from humans and animals as a source of infection in poultry between 2002 and 2003. A total of 50 C. jejuni isolates from humans and 29 C. jejuni isolates from poultry were studied for serotype using the Penner serotyping scheme and the drug susceptibilities of the isolates which were determined for 7 antimicrobial drugs using the disk diffusion method. Serotype B (10%), serotype E (8%) and serotype R (8%) were found in humans isolates, while serotype A (27%) was most freguently isolated from poultry, followed by serotype K (21%) and serotype C (13%). Resistance in human isolates to cephalothin was high (100%). Resistance to trimethoprim/sulfamethoxazole, ciprofloxacin, and nalidixic acid were observed in 90, 82 and 78% of isolates, respectively. Most of the isolates (88%) were susceptible to erythromycin. High levels of resistance to drugs (ciprofloxacin and nalidixic acid) were observed in the isolates from poultry. These results indicate the importance of poultry as a reservoir of C. jejuni infection in Thailand is limited. In addition, a high proportion of the isolates were resistant to antimicrobial drugs, particularly the quinolone group.

Animals↗

Rapid detection of Streptococcus suis serotype 2 in weaned pigs.

A survey to detect Streptococcus suis serotype 2 in 1,716 weaned pigs was done in Quebec. Forty-nine sow herds were included in this survey: in 26 herds, S suis serotype 2 had been isolated during the preceding 12 months and in 23 herds (control), the organism had not been detected during a previous study. Swab specimens of the nasal cavity and tonsils of pigs were obtained for bacteriologic culture, and S suis serotype 2 was easily detected by the use of brain-heart infusion agar containing a Streptococcus-selective supplement and 5% goat antiserum raised against S suis serotype 2. After measurement of the diameter of the precipitation zone of 539 isolates, a slide agglutination test was performed to identify the S suis serotype 2 isolates. The mean precipitation zone diameter obtained for group S suis serotype 2 was larger (P less than 0.001) than that for the group designated as "others". With slide agglutination test results as reference and on the basis of discriminant analysis to stimulate detection of S suis serotype 2, 93.1% of all isolates were correctly classified, using the precipitation zone diameter as unique classification criterion. Relative specificity was 94.5% and relative sensitivity was 88.7%. Use of the precipitation zone diameter on a quantitative basis led to the proposal of a simple and reliable technique to screen swine herds for S suis serotype 2 in weaned pigs. Nasal and tonsillar swab specimens were obtained and analyzed concurrently for S suis serotype 2. The organism was found in both sites in only 20.4% of 103 carrier pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗