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Serotype analysis of group A human rotavirus related to acute gastroenteritis in winter in Gifu city.

A total of 348 fecal specimens collected from children with acute gastroenteritis in Gifu city over three consecutive winter seasons (from November 1986 to March 1989) were examined for group A human rotavirus (HRV) by either a commercial test kit or a sandwich enzyme-linked immunosorbent assay (sandwich ELISA). One hundred twelve of the 173 group A HRV-positive specimens were further subjected to serotype determination by ELISA with four serotype-specific monoclonal antibodies to VP7 (ELISA-serotyping). Ninety-one specimens (81.3%) were successfully serotyped: 41 (36.6%) were serotype 1, 13 (11.6%) serotype 2, 27 (24.1%) serotype 3, and 10 (8.9%) serotype 4. The serotypes of the remaining 21 (18.8%) could not be determined. The predominant serotype of HRV that prevailed in Gifu city changed every winter: serotype 3 (63.4%) was most prevalent in the 1st winter, serotype 4 (42.9%) in the 2nd winter, and serotype 1 (64%) in the 3rd winter.

Adolescent↗

Human rotavirus subgroups and serotypes in children with acute gastroenteritis in Saudi Arabia from 1988 to 1992.

Rotavirus infection was detected in 524 (42.2%) of the 1,242 stool specimens collected from infants and young children with acute gastroenteritis admitted to a major pediatric hospital in Jeddah, Saudi Arabia, between March 1988 and December 1992. Enzyme-linked immunosorbent assay (ELISA) and monoclonal antibodies specific for subgroup I and II were used to examine 80 rotavirus positive specimens. Subgroup I was detected in 21 (26.3%) and subgroup II in 49 (61.3%) specimens. Six specimens reacted with both subgroup I and II monoclonal antibodies and four specimens were untypeable. Serotyping of 355 rotavirus positive specimens using monoclonal antibodies specific for the human rotavirus serotypes 1 to 4 revealed a distribution profile of serotype 1, 53.5%; serotype 2, 6.8%; serotype 3, 5.9%; and serotype 4, 22.8%, along with mixed and untypeable specimens (11%). When the correlation between subgroup and serotype specificities was examined in 62 specimens, all subgroup I specimens were found to be serotype 2 or untypeable and all subgroup II specimens belonged predominantly to serotypes 1 (54.7%) and 4 (9.4%). Serotype 1, followed by, to a lesser extent, serotype 4, exhibited a temporal predominance in the 5-year investigation. A significant clustering of the various serotypes during the cooler months was evident almost throughout the study, particularly in 1989 and 1990.

Acute Disease↗

Serotype A and B strains of bean common mosaic virus are two distinct potyviruses.

The serological relationships among strains of bean common mosaic virus (BCMV) (genus Potyvirus, family Potyviridae) were investigated by testing 13 isolates of the 10 known BCMV pathotypes with two monoclonal antibodies and six antisera to BCMV strains. In addition, other properties of serologically distinct BCMV strains were compared. Two groups of BCMV strains were obtained by ELISA and Western blot serology: serotype A contained the BCMV strains NL3, NL5, and NL8 and serotype B contained the BCMV strains NL1, NL2, NL4, NL6, US4, NL7, NY15, and Fla. SDS polyacrylamide gel electrophoresis and Western blotting of freshly purified preparations, and of extracts from leaves infected with eleven BCMV strains showed that the apparent molecular mass of the capsid protein of the serotype A isolates NL3, NL5, and NL8 are lower (about M(r) 33,000) than those of the serotype B isolates (M(r) 34,500 to 35,000). The normal lengths of the particles of the serotype A isolates were shorter (810-818 nm) than those of most isolates (except NL6 and NY15) of serotype B (847-886 nm). All isolates studied induced cytoplasmic pinwheel and scroll inclusions. Cells infected with serotype A isolates contained a specific type of proliferated endoplasmic reticulum which was never found in cells infected with serotype B isolates. The capsid protein gene of a representative member of each serotype was cloned and sequenced. Molecular mass calculations based upon nucleotide sequence-derived amino acid sequences yielded M(r) of 29,662 and 32,489 for the capsid proteins of the serotype A isolate NL8 and the serotype B isolate NL4, respectively. Comparison of the coat-protein sequences showed considerable differences at the N-termini whereas the core regions and the C-termini appeared to be highly conserved. Marked differences were also observed within the 3' non-coding regions of cloned cDNAs of NL 4 and NL 8. The striking differences between the two serotypes of BCMV strongly suggest that they be classified as two distinct potyviruses which naturally infect Phaseolus beans.

Amino Acid Sequence↗

Immunological and molecular comparison of fowl adenovirus serotypes 4 and 10.

Some discussion has centered on whether fowl adenovirus (FAV) serotypes 4 and 10 are distinct serotypes or in fact should be reclassified as a single serotype. We have undertaken a detailed characterisation of representatives of both serotypes in order to determine if types 4 and 10 should be grouped together or retained as distinct serotypes. Examination at the genomic level has revealed considerable similarities and few differences between these 2 serotypes. DNA cross-hybridization failed to distinguish between them and restriction enzyme analysis demonstrated limited sequence differences. In vivo studies demonstrated the cross-protection afforded by a natural route vaccination with serotype 4 FAV when chickens were challenged with serotype 10 FAV. On the basis of these studies it is suggested that these FAV serotypes be combined in future FAV classification. Physical maps for both serotype 4 and 10 have been constructed using the restriction enzymes Hpa I, Dra I, Nde I, Xba I and Not I for both serotypes and in addition Eco RI, Sfi I, Sma I and BglII for serotype 10.

Animals↗

Inter-serotype comparison of polysaccharides produced by extracellular enzymes from Streptococcus mutans.

The biochemical and morphological characteristics of polysaccharides synthesized from sucrose by extracellular enzymes from D-glucose-grown Streptococcus mutans representing serotypes a-g were compared. The polysaccharides synthesized by the enzymes from serotypes a, d, and g formed visible aggregates and firmly adhered to glass surfaces, whereas those formed by the enzymes from serotypes b, c, e, and f floated homogeneously and were poorly adherent. The enzymes of serotypes a, d, and g produced large amounts of water-insoluble polysaccharides (IPs, D-glucans), and those of serotypes b, c, e, and f water-soluble polysaccharides (SPs, D-glucans and D- fructans ). As compared with the IPs of serotypes b, c, e, and f, the IPs of serotypes a, d, and g (a) contained a higher proportion of (1----3)-alpha-D-glucosidic linkages and alpha-D-(1----3,6) branch linkages; (b) showed higher susceptibility to (1----3)-alpha-D-glucanase (serotype a excepted) and lower (1----6)-alpha-D-glucanase sensitivity; (c) contained larger amounts of high-molecular-weight fractions; (d) showed higher intrinsic viscosities (serotype b excepted); and (e) had lower S. mutans cell-agglutination activities. On electron-microscope observation, the IPs of all serotypes showed two fibrillar components; a double-stranded fibril, with short, fluffy protrusions extending out of its periphery, and a fine, single-stranded fibril. Thus, the serotypes could be divided into two major groups: a, d, and g; and b, c, e, and f. No similar grouping of serotypes was indicated by the chemical and morphological properties of SPs.

Polysaccharides↗

Bovine neutrophil activation by culture fluid from Pasteurella haemolytica serotypes A1 and A11.

Neutrophil activation has been thought to contribute to the pathogenesis of fibrinous pneumonia caused by Pasteurella haemolytica serotype A1. The activation of bovine neutrophils by culture fluid from the pathogenic P. haemolytica serotype A1 and the non-pathogenic serotype A11 was compared. Logarithmic-phase bacteria of each serotype were incubated in RPMI 1640-medium for 3 h at 37 degrees C. The culture fluid was collected by centrifugation and concentrated by ultrafiltration. The concentrated culture fluids were then tested for their ability to induce chemotaxis and respiratory burst in bovine neutrophils. Chemotactic activity was of similar magnitude in response to both serotypes. An early chemiluminescence response occurred at 5 min at 1:100 dilution and a late peak at 11 min at 1:500 dilution for serotype A1. The early peak was absent at all dilutions tested for serotype A11. Maximal chemiluminescence response was observed at 1:25 dilution with serotype A11 while maximal response was seen at 1:500 dilution with the culture fluid from serotype A1. Superoxide anion release was greater in response to culture fluid from A1 than A11 at all dilutions tested. Leukotoxin activity was 50-fold higher in culture fluid from serotype A1 than in culture fluid from serotype A11. In this study, the ability of P. haemolytica to attract and activate bovine neutrophils was not restricted to the pathogenic serotype A1.

Animals↗

Differentiation of the seven serotypes of foot-and-mouth disease virus by reverse transcriptase polymerase chain reaction.

A strategy for reverse transcriptase polymerase chain reaction (RT-PCR) using multiple primers was developed to detect and to differentiate the seven serotypes of foot-and-mouth disease virus (FMDV) simultaneously, quickly and accurately. The development of the test was carried out on virus isolates grown in tissue culture prior to cDNA synthesis and PCR using various sets of primers. Primers P33 and P32 were used for the consensus PCR to detect FMDV regardless of the serotype. Positive cDNA was assayed in two multi-primer PCR mixes containing type-specific primers capable of distinguishing between the seven serotypes. The serotype-specific primers were selected to correspond to regions of the genome coding for parts of the VP1 polypeptide that is responsible for the antigenic diversity of the virus group. Multi-primer mix P33-P(A-C-O-ASIA 1) gave products of 732, 596, 402, 292 bp for the A,C,O and ASIA 1 serotypes, respectively, and no target products for South African Territories serotypes (SAT 1, SAT 2 and SAT 3). The multi-primer mix P33-P(A-C-O-ASIA 1) was also capable of detecting a mixture of two different serotypes. Multi-primer mix P1-P(SAT 1-3-2) gave products of 246, 201 and 75 bp for the SAT 1, SAT 3 and SAT 2 serotypes, respectively, and no specific products for serotypes A, C, O and ASIA 1. This is the first PCR assay to be described that differentiates between the SAT serotypes of FMDV. The method has been applied to 25 cell-culture-derived isolates of the SAT serotypes of FMDV and the results were totally compatible with the standard techniques for FMDV detection and serotyping.

Animals↗

Actinobacillus actinomycetemcomitans serotype e--biotypes, genetic diversity and distribution in relation to periodontal status.

Actinobacillus actinomycetemcomitans isolates from 356 individuals were screened for identification of serotype e in order to investigate its distribution in relation to periodontal status. From subjects with serotype e, 1-6 isolates per subject (n = 61) were genotyped using arbitrarily primed-polymerase chain reaction (AP-PCR) and apaH gene polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis to determine the genetic heterogeneity within the serotype. Furthermore, one serotype e strain per subject was tested for fermentation of 8 carbohydrates for biotyping. Among patients with adult periodontitis (n = 219), localized juvenile periodontitis (n = 55) and other forms of early-onset periodontitis (n = 18) serotypes b, a and c, respectively, were the most frequently detected serotypes. Non-periodontitis subjects (n = 64) were predominantly colonized with serotype c. Serotype e was found in 30 (14%) adult periodontitis patients, 2 (11%) early-onset periodontitis patients and in 5 (8%) non-periodontitis individuals, but in none of the 55 localized juvenile periodontitis patients. AP-PCR distinguished 3 and apaH gene PCR-RFLP analysis 2 genotypes among the 61 A. actinomycetemcomitans serotype e isolates, one genotype per subject. The AP-PCR genotypes 1 and 3 represented the apaH genotype 1 and the AP-PCR genotype 2 the apaH genotype 2. On the basis of variable fermentation of galactose and xylose, 3 biotypes among A. actinomycetemcomitans serotype e were established. Contrary to the absence of A. actinomycetemcomitans serotype e in localized juvenile periodontitis patients, its detection frequency was comparable among other forms of periodontitis and periodontal health. Clinical serotype e isolates form at least 2 genetic types and 3 biotypes.

Adolescent↗

Serotyping and genotyping of hepatitis C virus in Taiwanese patients with type C chronic liver disease and uraemic patients on maintenance haemodialysis.

BACKGROUND: To evaluate a recombinant immunoblot hepatitis C virus (HCV) serotyping assay, which determines HCV serotypes 1, 2, and 3 by detecting type-specific antibodies to core-and NS-4-derived peptides. METHODS: Immunoreactivity of type-specific antibodies among 173 chronic hepatitis C patients and 43 haemodialysis patients in Taiwan was examined and the serotyping results were compared with genotyping by Okamoto's method. Serial specimens from 29 patients undergoing interferon-alpha therapy were also evaluated. RESULTS: Of the 205 specimens for which genotyping data were available, 51.2% were of serotype 1, 31.7% of serotype 2, 1.0% of serotype 3, 2.4% of either serotype 1 or 3, and the remaining 13.7% were untypable. The serotypable rate was significantly lower in haemodialysis patients than in chronic hepatitis C patients (70.0% vs 94.9%; P < 0.001). Serotyping of genotype 2b specimens was significantly more dependent on core peptide bands than other genotypes. Using genotyping as the reference, the overall sensitivity, specificity and concordance of the recombinant immunoblot HCV serotyping assay were 86.3%, 97.2% and 83.9%, respectively. However, the serotyping assay had significantly lower sensitivity (69.2%), specificity (77.8%) and concordance (53.8%) for genotype 2b specimens. Of nine HCV complete responders, one lost type-specific antibodies 6 months after the cessation of interferon-alpha treatment. CONCLUSIONS: These results suggest that, except for less than optimal performance with immunocompromised or genotype 2b patients, the HCV serotyping assay is a practical and useful method for HCV typing in the clinical setting in Taiwan.

Female↗

Difference in the structural features of streptococcal M proteins from nephritogenic and rheumatogenic serotypes.

The association of only certain M protein serotypes of group A streptococci with acute glomerulonephritis is very well recognized. Structural information on the M protein, a dimeric alpha-helical coiled-coil molecule, has come so far from three rheumatogenic serotypes, 5, 6, and 24. However, M proteins from the nephritogenic serotypes have not been well characterized. In the present study, we have isolated a biologically active 20,000 Mr pepsin fragment of type 49 M protein (PepM49), a nephritogenic serotype, and purified it to homogeneity using DEAE-Sephadex and gel filtration. The amino acid composition of PepM49 is similar to those of the rheumatogenic M protein serotypes PepM5, PepM6, and PepM24. However, the sequence of the NH2-terminal 60 residues of PepM49 shows little homology to any of these M protein serotypes, although the latter have significant homology among themselves. Nevertheless, PepM49 exhibits a strong heptad periodicity in its nonpolar residues, suggesting its overall conformational similarity with the other M molecules. During the course of the present studies, Moravek et al. (17) reported the NH2-terminal sequence of another M protein serotype, PepM1, which also does not exhibit much homology with the PepM5, PepM6, and PepM24 proteins. Our analysis of this sequence revealed that the PepM1 protein also exhibits a heptad periodicity of the nonpolar amino acids. A closer examination has revealed that the pattern of heptad periodicity in PepM49 and PepM1 proteins is more regular and more similar to each other than has been previously seen for the PepM5, PepM6, and PepM24 proteins. PepM1 is also a nephritogenic serotype. Taken together, these findings indicate an underlying conservation of the tertiary structure of the various M protein serotypes, despite the complexity in their antigenic variation and suggest that the nephritogenic M protein serotypes M1 and M49 may be further apart evolutionarily from the rheumatogenic serotypes 5, 6, and 24. The distinct differences in the structural features of the PepM1 and PepM49 proteins relative to the PepM5, PepM6, and PepM24 proteins are also suggestive of a correlation with the earlier broader classification of the group A streptococci into rheumatogenic and nephritogenic serotypes.

Amino Acid Sequence↗

HIV disease progression and V3 serotypes in Brazil: is B different from B-Br?

HIV-1 serotype B-Br (GWGR) is rare in the United States but predominates in Brazil. Differences in prognosis for patients infected with serotype B-Br or serotype B (GPGR) have not been addressed previously. In this prospective cohort study, we compared the rate of disease progression between patients infected with the HIV-1 V3 serotype B or B-Br in Brazil. Progression to AIDS or death was studied by the Kaplan-Meier and Cox proportional hazard methods. Among 445 HIV-infected patients who were tested with a specific enzyme immune assay, 204 (46%) had serotype B-Br infection and 127 (28%) had serotype B infection. Both groups were similar with regard to baseline CD4+ cell count, serum HIV RNA viral load, initial clinical stage, and the proportions who were treated with antiretroviral drugs. Patients with serotype B infection were significantly younger (p = 0.005) and tended to report homosexual behavior more frequently (p = 0.08). Mean follow-up was 30 +/- 13.5 months. During the study period, 41 (32%) patients infected with serotype B and 44 (22%) infected with serotype B-Br developed AIDS (p = 0.03). In a regression model adjusted for age and risk factor for HIV infection, progression to AIDS was faster in patients infected with serotype B (hazard ratio [HR] 1.59; 95% CI, 1.03-2.43; p = 0.03). A similar trend was observed in a model that considered AIDS or death as the outcome (HR, 1.43; 95% CI, 0.95-2.0; p = 0.09). These results suggest that patients infected with closely related HIV-1 serotypes may differ in the rate of progression to AIDS and indicate that serotype should be taken into account in HIV vaccine studies in Brazil.

Acquired Immunodeficiency Syndrome↗

Identification by monoclonal antibodies of serotype D strains of Pasteurella multocida representing various geographic origins and host species.

Two outer-membrane proteins (OMPs) of Pasteurella multocida serotype D, designated H and W, possess potentially important serotype D-specific antigens. Antigenicity as well as toxigenicity of 55 strains of P. multocida representing various serotypes, geographic origins and host species were studied by SDS-PAGE, enzyme-linked immunosorbent assay (ELISA), immunoblot and polymerase chain reaction (PCR) assays. Based on the electrophoretic mobility of protein H, different OMP patterns were observed within different capsular serotypes. Three monoclonal antibodies (MAbs) designated MT1, MT2 and MT3 were produced against H and W proteins of P. multocida in BALB/c mice. MAbs MT2 and MT3 reacted with two distinct epitopes on W protein of serotype D in competitive ELISA. MAb MT1 reacted with all serotype D-I strains but not with D-II strains, whereas MAb MT2 reacted with both serotype D-I and D-II strains in dot-ELISA and immunoblot assay. MAb MT3 reacted with all P. multocida strains belonging to different capsular serotypes in dot-ELISA. None of the MAbs reacted with other gram-negative bacteria tested, indicating that protein H has a serotype D-I specific epitope and protein W has both serotype and species-specific epitopes. PCR assay was used to identify toxigenic strains of P. multocida; 92% of P. multocida strains possess both toxA gene and MAb MT2 reacting epitope, suggesting a strong association between MAb MT2 reacting epitopes and toxA gene. Rapid dot-ELISA with MAb was found to be specific, sensitive and easy to perform and thus suitable for routine serotyping of P. multocida serotype D strains which might be potentially pathogenic.

Animals↗

PCR-based assays for detection of Streptococcus pneumoniae serotypes 3, 14, 19F and 23F in respiratory specimens.

Current culture-based assays are insensitive for detection of simultaneous respiratory tract colonization by more than one pneumococcal serotype. Separate single-tube, nested PCR-based assays have been developed to detect Streptococcus pneumoniae serotypes 3, 14, 19F and 23F by amplifying unique DNA sequences in the capsular polysaccharide gene cluster of each serotype. Pairs of 27-32-base outer primers and 20-21-base inner primers and a 20-22-base probe were designed to amplify and detect a 200-221-base sequence by dot blotting using the labelled probe. Sensitivity of the assays was 0.01-10 fg using chromosomal DNA and < or = 1 viable cell using DNA extracted from exponential-phase bacteria. Each serotype-specific assay detected chromosomal DNA from all of five to ten clinical isolates of the homologous type and did not detect DNA sequences from any of 190-204 strains from 51-52 different serotypes or 28 non-pneumococcal bacterial strains. Sixteen throat swabs from children that had been cultured for S. pneumoniae were tested in PCR assays following DNA extraction. All of six that grew S. pneumoniae serotype 3, 14, 19F or 23F were positive in the PCR assay for the homologous serotype (and in a PCR assay for sequences in lytA, present in all pneumococci) and were negative in assays for other serotypes. Of eight culture-negative specimens in children not receiving antimicrobials, three were positive for both the lytA assay and an assay for one of the four serotypes, suggesting true positive results; in three others all five PCR assays were negative and, in the remaining two, the lytA assay was positive but each of the four assays for individual serotypes was negative, suggesting either false-positive results or presence of DNA sequences from an S. pneumoniae serotype other than 3, 14, 19F or 23F. These preliminary clinical data suggest that these PCR-based assays are sensitive and specific for detection of individual serotypes of pneumococci and may be used with respiratory tract specimens.

Bacterial Capsules↗

The relative frequencies of G serotypes of rotaviruses recovered from hospitalized children with diarrhea: A 10-year survey (1987-1996) in Japan with a review of globally collected data.

Since rotavirus vaccines aim to protect children from severe diarrhea, knowledge of the prevailing G serotypes among rotaviruses from hospitalized children is essential. Thus, we determined the G serotypes of rotaviruses collected from children with acute diarrhea in a local referral hospital in Akita, Japan, over the 10-year period between January 1987 and December 1996. Based on the assumption that rotaviruses with an identical electropherotype possess the same G serotype, the G serotypes of 488 rotavirus-positive specimens that were classified into 63 electropherotypes were determined by enzyme-linked immunosorbent assay with a supplementary use of G typing by reverse transcription-PCR. The relative frequencies over the 10-year period were 77.0 (G1), 14.5 (G2), 2.7 (G3) and 5.3% (G4), leaving the possibility that only 0.4% had G serotypes uncommon to human rotaviruses. Of 24,050 rotaviruses extracted by reviewing 63 serotyping studies in literature, the relative frequencies of the four major G serotypes were 50.6 (G1), 9.3 (G2), 7.2 (G3) and 11.6% (G4). As to uncommon G serotypes, only 0.9% were described as serotypes other than G1-4, and our estimate for potential uncommon serotypes were at most 8.1%. Thus, both this long-term study focusing on the rotaviruses only from severe cases in a single hospital in Japan and the global review of G serotypes published to date indicate that the primary target of any rotavirus vaccines should be rotaviruses possessing serotypes G1-4.

Child↗

Frequency and stability of mono- or poly-infection by Actinobacillus actinomycetemcomitans serotypes a, b, c, d or e.

The aims of the study were to determine the prevalence of simultaneously multiple Actinobacillus actinomycetemcomitans serotypes in one individual, stability of infection by the same serotype and the occurrence of previously not described serotypes of A. actinomycetemcomitans. The serotypes of 515 clinical isolates of A. actinomycetemcomitans from 91 Finnish, Caucasian subjects, including 321 follow-up samples from 51 subjects, were determined with immunodiffusion assay. Most subjects (n = 86, 95%) were infected with one serotype only; 466 (91%) isolates from 80 subjects belonged to serotype a (25% of isolates/25 subjects), b (25% of isolates/27 subjects) or c (41% of isolates/30 subjects). Fifteen isolates from 4 subjects reacted with the antiserum raised against previously untypable clinical strain IDH 781 (serotype d) and 18 isolates from 5 subjects with the antiserum raised against strain IDH 1705 or IDH 3096 (serotype e). Sixteen (3%) isolates from 5 subjects remained untypable. The same infecting A. actinomycetemcomitans serotype(s) persisted for the 1-6 years of follow-up. In conclusion, the study indicates a rare simultaneous occurrence of multiple oral A. actinomycetemcomitans serotypes, the stability of infection by the same serotype(s) and the existence of serotypes of A. actinomycetemcomitans not previously described.

Actinobacillus Infections↗

In vitro antimicrobial susceptibility of different serotypes of Actinobacillus actinomycetemcomitans.

In vitro susceptibility of Actinobacillus actinomycetemcomitans (A.a.) serotypes to selected antimicrobial agents was investigated by the agar dilution method on supplemented Mueller-Hinton test medium. Eighty-three A.a. strains, 80 recent isolates from 40 periodontally healthy or diseased subjects, and three type strains were included in the study. Serotype a represented 20, serotype b 32, serotype c 17, and serotype e 7 and nontypable 4 of the tested strains. The most effective drugs against all A.a. serotypes in vitro were cefaclor, cefuroxime, tetracycline hydrochloride, doxycycline, trimethoprim-sulfamethoxazole (cotrimoxazole), and ciprofloxacin, which inhibited 100% of the strains at 4.0 micrograms/ml, 4.0 micrograms/ml, 1.0 microgram/ml, 2.0 micrograms/ml, 0.06 microgram/ml, and 0.015 microgram/ml, respectively. Serotypes a and e were more susceptible to cefaclor and cefuroxime than were serotypes b and c; 100% of the first two groups were inhibited at 2.0 micrograms/ml and 1.0 microgram/ml. Ampicillin inhibited 92% of the tested strains at 1.0 microgram/ml. Serotype b was always susceptible to ampicillin. Metronidazole exhibited the best activity against serotype a strains. The lowest minimal inhibitory concentration values for benzylpenicillin, ampicillin, erythromycin, doxycycline, and metronidazole were encountered among serotype b isolates. The results of the present study indicate minor differences in the in vitro antimicrobial susceptibility patterns of different A.a. serotypes, except to metronidazole. Also, the new oral cephalosporins and cotrimoxazole, rare antimicrobial agents in periodontology, showed promising efficacy against all A.a. strains.

Aggregatibacter actinomycetemcomitans↗

Relationship of Actinobacillus actinomycetemcomitans serotypes to periodontal condition: prevalence and proportions in subgingival plaque.

No study available has utilized the new classification scheme (the consensus report of the American Academy of Periodontology 1999) to determine the prevalence of Actinobacillus actinomycetemcomitans in different periodontal conditions. The purpose of this study was to investigate prevalence and proportions of A. actinomycetemcomitans serotypes in subgingival plaque samples from a young Taiwanese population with aggressive periodontitis, chronic periodontitis and no periodontal disease. A total of 221 subgingival plaque samples from 171 diseased subjects (70 had aggressive periodontitis, and 101 had chronic periodontitis) (mean age 25.0 +/- 8.2 yr) and 50 periodontally healthy subjects (mean age 18.4 +/- 9.5 yr) were screened for A. actinomycetemcomitans. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523 (serotype a), ATCC 43728 (serotype b) and ATCC 33384 (serotype c). Prevalence (% of positive samples) of A. actinomycetemcomitans was 84.3% in aggressive periodontitis, 60.4% in chronic periodontitis, and 64.0% in periodontally healthy subjects. Proportions of A. actinomycetemcomitans (mean percentage per total bacteria) in periodontally healthy subjects were significantly lower than in aggressive periodontitis subjects. The proportion of serotype b in subjects with aggressive periodontitis and subjects with chronic periodontitis were significantly greater than that in periodontally healthy subjects. The proportion of serotype c in periodontally healthy subjects was much higher than that in chronic periodontitis subjects. The results of this study suggest that prevalence and proportions of A. actinomycetemcomitans are significantly greater in patients with aggressive periodontitis than in those with chronic periodontitis. Serotype b is the predominant serotype of A. actinomycetemcomitans in patients with diseased periodontal conditions. Serotype c is a more common serotype detected in periodontally healthy subjects.

Actinobacillus Infections↗

Prevalence of Actinobacillus actinomycetemcomitans serotypes in Japanese patients with periodontitis.

Oral Actinobacillus actinomycetemcomitans strains are serologically classified into 5 distinct groups, a to e. We examined the distribution of A. actinomycetemcomitans serotypes in Japanese patients with periodontitis. A total of 157 A. actinomycetemcomitans clinical isolates from diseased sites of 39 patients with periodontitis were serotyped by using serotype-specific rabbit antisera against A. actinomycetemcomitans serotypes a, b, c, d and e strains. In the immunodiffusion assay, autoclaved extracts of 42, 6, 39, 9 and 41 A. actinomycetemcomitans clinical isolates reacted with serotypes a, b, c, d and e antisera, respectively. Although 37 patients were infected with a serotype strain, 2 patients harbored 2 different serotype strains, b/e and b/untypeable. To establish a correlation between serotype and genotype of A. actinomycetemcomitans clinical isolates from 2 patients who had different serotype strains, we used arbitrarily primed polymerase chain reaction (AP-PCR) to fingerprint clinical isolates of different serotypes. The AP-PCR genotypes among 4 clinical isolates (b/e and b/untypeable) were identical to that of A. actinomycetemcomitans Y4 (serotype b), indicating the presence of multiple A. actinomycetemcomitans serotypes which are genetically homogeneous in the periodontally diseased sites of patients with periodontitis.

Actinobacillus Infections↗