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PubMed1989

Serotype-related differences in production and type of heat-labile hemolysin and heat-labile cytotoxin of Actinobacillus (Haemophilus) pleuropneumoniae.

Reference strains of serotypes 1 to 12 of Actinobacillus (Haemophilus) pleuropneumoniae were cultured in Eagle minimal essential medium with 10% Serum Plus. Culture supernatants were examined for cytotoxicity to alveolar macrophages and for the ability to hemolyze sheep erythrocytes. All strains except the reference strain of serotype 6 produced cytotoxin, whereas only serotypes 1, 5, 9, 10, and 11 produced hemolysin. Both cytotoxin and hemolysin appeared to be heat labile. Antisera were raised against cytotoxin- and hemolysin-containing culture supernatants of serotypes 1 to 11. Cross-neutralization studies revealed that the hemolysins were serologically homogeneous. In contrast, four serologically different cytotoxins were distinguished. One cytotoxin was produced by serotypes 1, 5, 9, and 11, and a second was produced by serotypes 2, 3, 4, and 8. A third cytotoxin was produced by serotypes 7 and 12; this cytotoxin was related to the cytotoxins of serotypes 1, 2, 4, 5, 9, and 11. A fourth cytotoxin, produced by serotype 10, was related to the cytotoxin of serotypes 1, 5, 9, and 11. Seventy field strains belonging to serotypes 2, 3, 7, 8, 9, and 11 were also tested for production of cytotoxin and hemolysin. All strains belonging to serotypes 9 and 11 produced hemolysin and cytotoxin, whereas all strains of serotypes 2, 3, 7, and 8 produced only cytotoxin. Hemolysins and cytotoxins of both the field strains and the corresponding serotype reference strains were comparably neutralized. These findings strongly suggest that the observed differences in production and type of hemolysin and cytotoxin were related to serotype and not to strain.

Actinobacillus↗
PubMed1996

Assessment of commercial enzyme immunoassay for hepatitis C virus serotyping.

AIMS: To assess a commercial enzyme immunoassay (EIA) for the serotyping of hepatitis C virus (HCV) for routine use in a diagnostic laboratory setting, as well as for noting the serotype prevalence of selected specimens. METHODS: Seventy six serum specimens, submitted to the laboratory for routine hepatitis studies between May 1992 and February 1996 and stored at -20 degrees C, were evaluated. These specimens were categorised into specific hepatic, renal, and paediatric clinical conditions. The specimens all tested positive for HCV antibodies on a screening EIA, with confirmation on a recombinant immunoblot assay (RIBA). Certain specimens were also HCV RNA positive by the reverse transcription polymerase chain reaction (RT-PCR). All the specimens were serotyped using the newly developed serotyping EIA. RESULTS: Twenty seven (35.5%) specimens were typable. Type 5 predominated (56%), followed by type 1 (33%), types 1 and 6 (7%) and type 3 (4%). The serotype 5 specimens showed 85% and 90% reactivity with recombinant antigens c100-3 and c22-3c, respectively; serotype 1 specimens showed 75% and 100% reactivity with these antigens. All serotype 5 specimens reacted with the c33-c antigen, but only 60% of serotype 1 specimens reacted with this antigen. The differences in the reactivity of the serotype 5 and serotype 1 specimens for c33-c antigen in the RIBA were significant, but no significant differences in reactivity for antigens c-1-1, c100-3, and c22-3 were noted. Serotype 3 specimens showed equal reactivity with all four antigens used in the RIBA. CONCLUSION: The serotyping EIA was easy to use, rapid, and cost effective compared with molecular assays. This assay seems to be ideal for the routine diagnostic laboratory setting, but could not be used for certain clinical specimens. The demonstration of serotypes 5, 1, and 3 was not unexpected in this cohort. The occurrence of serotype 6, although concurrent and more likely to be a false cross reaction with serotype 1 peptides, requires confirmation by molecular genotyping before it can be claimed that this type is present in South Africa.

Adolescent↗
PubMedDate not supplied

[Frequency of serotype G rotavirus isolated from children with diarrhea in Mérida, Yucatán, Mexico].

During a period of six years (1985-1990), rotavirus G serotypes were investigated in 104 fecal samples isolates according to an immune enzyme assay using specific monoclonal antibodies against serotypes 1, 2, 3, and 4 of the VP7. The serotypes were established in 65 samples (62.5%) and could not be determined in 39 samples. In the 65 classified serotypes, 7 (6.7%) were found to belong to serotype 1, 23 (22.1%) to serotype 2, 12 (11.5%) to serotype 3, and 23 (22.1%) to serotype 4. The occurrence of the four serotypes during the six years was: serotype 3 was present in three of the six years; serotype 2 was detected in two epidemic outbreaks (1989 and 1990); serotype 3 appeared in the second year and was seen in the remainder of the study; and serotype 4 was present in the six years. We conclude that the four serotypes occur in our population and that future efforts to test the efficacy of any vaccine against this virus should evaluate a protective response against the four serotypes.

Antibodies, Monoclonal↗
PubMed1996

Inter-relationships among subgroups, serotypes, and electropherotypes of rotaviruses isolated from humans.

In an epidemiological study of human rotavirus (HRV) infections in metro Jeddah, Saudi Arabia, the relationships among subgroups, serotypes, and RNA electropherotypes of the rotavirus isolates were investigated. Of the 523 rotavirus-positive stool specimens, 245 were examined for subgroup, serotype, and electropherotype. Of these, 84 isolates were analyzed for their subgroup and RNA electropherotype specificites, 12 (14.3%) were of subgroup 1, 69 (82.1%) were of subgroup II, and 3 (3.6%) were a mixture of subgroup I and II. Of the subgroup 1 specimens, 5 (41.7%) showed long electrophoretic migration patterns and 7 (58.3%) showed short patterns. In subgroup II specimens, 66 (95.7%) were of long patterns and 3 (4.3%) of short patterns. The relationship between HRVS serotypes and electropherotypes was also determined for the same 245 rotavirus specimens. Of these, 36 (14.7%) exhibited short RNA patterns and 209 (85.3%) exhibited long patterns. The short pattern specimens consisted of serotype 1 (8.3%), serotype 2 (63.9%), serotype 3 and serotype 4 (2.8%) each. The long pattern specimens consisted of serotype 1 (60.3%), serotype 2 (1.4%), serotype 3 (7.2%) and serotype 4 (17.7%). Among the previous 245 specimens, subgroup specificities were available for 51 specimens. All subgroup I were of serotype 2, and all subgroup II were of serotype 1, 3 or 4. RNAs of either subgroup showed both long and short electropherotypes. No relationship could be established between subgroups or serotypes and a particular electropherotype. It seems unlikely that electropherotyping of human rotavirus (HRV) can be used for identifying the subgroups or serotypes of strains.

Child, Preschool↗
PubMed1996

Immunogenicity, safety and protective efficacy of one dose of the rhesus rotavirus vaccine and serotype 1 and 2 human-rhesus rotavirus reassortants in children from Lima, Peru.

In a four cell trial, a single 10(4) plaque-forming unit dose of rhesus rotavirus (RRV) vaccine (serotype G3), a human rotavirus-rhesus rotavirus reassortant vaccine with serotype G1 specificity, a similar vaccine with serotype G2 specificity, or a placebo was administered with buffer orally at 2 months of age to 800 Peruvian infants. Only the RRV vaccine was associated with a febrile response (< 38 degrees C) that occurred in 9% of the infants on day 4 after vaccination. Diarrhea or other side-effects were not associated with administration of vaccine. Vaccine strains were shed by only 12-18% of the infants as determined by examination of a single stool specimen obtained on days 4 or 5 after vaccination. Fifty per cent of vaccines developed an IgA ELISA seroresponse; however, a serotype-specific seroresponse by plaque reduction neutralization was demonstrated in < 20% of the participants against each of the three candidate vaccine strains. Vaccine efficacy was evaluated by twice-weekly home surveillance for diarrheal diseases during 24 months post-immunization. Rotavirus diarrheal episodes were identified by ELISA. Only the RRV vaccine had a significant protective efficacy (29%, p = 0.03, chi-square test) against rotavirus diarrhea. Analysis of vaccine efficacy against rotavirus episodes of any severity in which no other enteropathogen was isolated showed a trend towards higher vaccine efficacy. In addition, a similar trend was observed in rotavirus-only episodes in which there was some degree of dehydration or when health services were utilized. Serotype G1 or G2 rotavirus strains were most prevalent during surveillance. Neither serotype G1 or serotype G2 vaccines were protective against serotype 1 or 2 rotavirus diarrhea, respectively. The serotype G2 vaccine was 84% protective against serotype 1 and 2 dehydrating rotavirus diarrhea in the small numbers of individuals evaluated. We conclude that one dose of 10(4) p.f.u. of the RRV, serotype G1, or serotype G2 rotavirus vaccine failed to induce either an adequate serotype-specific seroresponse or serotype-specific protection in children immunized at 2 months of age. Only the RRV vaccine induced a low level of protection against rotavirus diarrhea mainly of serotype G1 specificity. Future studies need to explore whether higher vaccine dose and/or more than one dose would increase the immunogenicity and efficacy of the rotavirus vaccine, especially in developing countries with a high level of baseline rotavirus antibodies.

Diarrhea, Infantile↗
PubMed2005

Host restriction of Salmonella enterica serotype Typhi is not caused by functional alteration of SipA, SopB, or SopD.

Salmonella enterica serotype Typhi is a strictly human adapted pathogen that does not cause disease in nonprimate vertebrate hosts, while Salmonella enterica serotype Typhimurium is a broad-host-range pathogen. Serotype Typhi lacks some of the proteins (effectors) exported by the invasion-associated type III secretion system that are required by serotype Typhimurium for eliciting fluid secretion and inflammation in bovine ligated ileal loops. We investigated whether the remaining serotype Typhi effectors implicated in enteropathogenicity (SipA, SopB, and SopD) are functionally exchangeable with their serotype Typhimurium homologues. Serotype Typhi elicited fluid accumulation in bovine ligated ileal loops at levels similar to those elicited by a noninvasive serotype Typhimurium strain (the sipA sopABDE2 mutant) or by sterile culture medium. However, introduction of the cloned serotype Typhi sipA, sopB, and sopD genes complemented the ability of a serotype Typhimurium sipA sopABDE2 mutant to elicit fluid secretion in bovine ligated ileal loops. Introduction of the cloned serotype Typhi sipA, sopB, and sopD genes increased the invasiveness of a serotype Typhimurium sipA sopABDE2 mutant for human colon carcinoma epithelial (HT-29 and T84) cells and bovine kidney (MDBK) cells. Translational fusions between the mature TEM-1 beta-lactamase reporter and SipA or SopD demonstrated that serotype Typhi translocates these effectors into host cells. We conclude that the inability of serotype Typhi to cause fluid accumulation in bovine ligated ileal loops is not caused by a functional alteration of its SipA, SopB, and SopD effector proteins with respect to their serotype Typhimurium homologues.

Animals↗
PubMed1995

Epizootic hemorrhagic disease virus and bluetongue virus serotype distribution in white-tailed deer in Georgia.

Serum samples collected from 1,396 white-tailed deer (Odocoileus virginianus) in five areas of Georgia (USA) from 1989 to 1991 were tested for precipitating and serum neutralizing (SN) antibodies to the enzootic North American epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV) serotypes. Precipitating antibodies to the EHDV or BTV serogroups, as detected by agar gel immunodiffusion (AGID) tests, were present in 35%, 29%, and 39% of deer sampled in 1989, 1990, and 1991, respectively. Significant differences (P < 0.05) in precipitating antibody prevalence were detected between physiographic regions during all years. Antibody prevalence consistently was highest in deer sampled from the Coastal Plain (77%), followed by the Piedmont (33%), Ridge and Valley (29%), Barrier Island (5%), and Blue Ridge (2%) regions. All AGID-positive samples were tested by SN tests for antibodies against all North American EHDV and BTV serotypes (EHDV serotypes 1 and 2, BTV serotypes 2, 10, 11, 13, and 17). Criteria for previous exposure to a specific serotype were either detection of monospecific results or clusters of positive results against that serotype. Serologic evidence of previous exposure to EHDV serotypes 1 and 2, and BTV serotypes 11 and 13 was detected during all years. Predominant serotypes varied among years. In general, evidence of exposure to EHDV serotype 2 appeared annually while exposure to BTV serotype 13 and EHDV serotype 1 decreased and increased, respectively. To determine serotype diversity prior to 1989, 134 AGID-positive white-tailed deer serum samples collected from 1967 to 1988 also were tested by SN. Evidence of exposure to EHDV serotypes 1 and 2 and BTV serotypes 11, 13, and 17 was detected.

Age Distribution↗
PubMed1994

Determinants of serotype specificity in transcription of vesicular stomatitis virus synthetic nucleocapsids.

Transcription of the nucleocapsid template of vesicular stomatitis virus (VSV) is serotype specific, since the viral RNA polymerase of the VSV Indiana (Ind) serotype transcribes the Ind nucleocapsid but not the nucleocapsid of the VSV New Jersey (NJ) serotype and, similarly, the NJ RNA polymerase transcribes only the NJ nucleocapsid. We have prepared synthetic nucleocapsid templates from various combinations of purified leader gene RNA and N protein of these two VSV serotypes for analysis of serotype specificity in vitro. In agreement with previous observations, in vitro transcription of synthetic homologous nucleocapsids with the 3' terminal leader RNA gene of either the (+) or (-) strand sense and the N protein of the same serotype is also serotype specific. We show with chimeric nucleocapsids, where the RNA and N protein are of different serotypes, that both components of the template are important for specificity, although the specifics depend on the serotype from which the RNA polymerase is derived. The Ind RNA polymerase will transcribe only the homologous nucleocapsids where both the RNA and N protein are of the Ind serotype, and not the chimeric nucleocapsids. In contrast, the NJ RNA polymerase is active not only on the homologous synthetic nucleocapsid, but also gives significant levels of transcription as long as one of the nucleocapsid components (N protein or RNA) is of the NJ serotype. The divergent RNA sequence of the distal portion of the leader gene (nt22 to 50/51) seems to be a major determinant for specificity, since transcription of synthetic nucleocapsids containing just the conserved proximal 1-22 nucleotides is significantly less serotype-restricted. Restriction appears to occur at the level of elongation of the product rather than initiation of RNA synthesis, since synthesis of template-length RNA, but not reiterated small initiation products, is inhibited. In addition, the serotype of the P protein subunit of the RNA polymerase also contributes to the serotype specificity of transcription, since the NJ P protein can bind equally to NJ and Ind nucleocapsids, while Ind P protein binds preferentially to Ind nucleocapsids.

Animals↗
PubMed1989

Rotavirus serotypes causing acute diarrhoea in hospitalized children in Yogyakarta, Indonesia during 1978-1979.

Rotavirus strains in stool specimens from 111 children aged 3-24 months admitted to hospital in Yogyakarta, Indonesia for treatment of acute diarrhoea were serotyped using VP7 serotype specific monoclonal antibodies in a double sandwich enzyme immunoassay. A serotype could be assigned to 59 of 111 specimens (53%). Inability to assign a serotype to 47% of specimens was probably due to loss of the outer capsid during transport of specimens from Indonesia to Australia. All four major human rotavirus serotypes were detected during the 15 month survey from June 1978 to August 1979, including one serotype 1, 5 serotype 2, 31 serotype 3, and 21 serotype 4 strains. One additional strain reacted with serotype 3 and 4 Mabs. Serotype 3 strains showed intratypic variation. The relative frequency of serotypes 2, 3, and 4 varied during the 15 months and appeared to be influenced by climatic changes associated with dry and wet seasons. Vaccine strategies must take account of comparatively rapid changes of predominant serotypes in a community and are only likely to be successful if comprehensive immunity can be established simultaneously against the four major human serotypes.

Acute Disease↗
PubMed2004

Multi-analyte single-membrane biosensor for the serotype-specific detection of Dengue virus.

A multi-analyte biosensor based on nucleic acid hybridization and liposome signal amplification was developed for the rapid serotype-specific detection of Dengue virus. After RNA amplification, detection of Dengue virus specific serotypes can be accomplished using a single analysis within 25 min. The multi-analyte biosensor is based on single-analyte assays (see Baeumner et al (2002) Anal Chem 74:1442-1448) developed earlier in which four analyses were required for specific serotype identification of Dengue virus samples. The multi-analyte biosensor employs generic and serotype-specific DNA probes, which hybridize with Dengue RNA that is amplified by the isothermal nucleic acid sequence based amplification (NASBA) reaction. The generic probe (reporter probe) is coupled to dye-entrapping liposomes and can hybridize to all four Dengue serotypes, while the serotype-specific probes (capture probes) are immobilized through biotin-streptavidin interaction on the surface of a polyethersulfone membrane strip in separate locations. A mixture of amplified Dengue virus RNA sequences and liposomes is applied to the membrane and allowed to migrate up along the test strip. After the liposome-target sequence complexes hybridize to the specific probes immobilized in the capture zones of the membrane strip, the Dengue serotype present in the sample can be determined. The amount of liposomes immobilized in the various capture zones directly correlates to the amount of viral RNA in the sample and can be quantified by a portable reflectometer. The specific arrangement of the capture zones and the use of unlabeled oligonucleotides (cold probes) enabled us to dramatically reduce the cross-reactivity of Dengue virus serotypes. Therefore, a single biosensor can be used to detect the exact Dengue serotype present in the sample. In addition, the biosensor can simultaneously detect two serotypes and so it is useful for the identification of possible concurrent infections found in clinical samples. The various biosensor components have been optimized with respect to specificity and sensitivity, and the system has been ultimately tested using blind coded samples. The biosensor demonstrated 92% reliability in Dengue serotype determination. Following isothermal amplification of the target sequences, the biosensor had a detection limit of 50 RNA molecules for serotype 2, 500 RNA molecules for serotypes 3 and 4, and 50,000 molecules for serotype 1. The multi-analyte biosensor is portable, inexpensive, and very easy to use and represents an alternative to current detection methods coupled with nucleic acid amplification reactions such as electrochemiluminescence, or those based on more expensive and time consuming methods such as ELISA or tissue culture.

Biosensing Techniques↗
PubMed1995

Prevalence of neutralizing antibodies to 9 rotavirus strains representing 7 G-serotypes in sheep sera.

Neutralizing antibodies to 9 rotavirus strains representing serotypes G1, G3, G5, G6, G8, G9, and G10 were investigated in 212 ovine serum samples from 3 age groups, 1-week-old lambs, 2- to 3-months-old lambs and adult sheep. All sera from 1-week-old lambs had neutralizing antibodies to all 9 rotavirus strains. Both neutralizing antibody titers and prevalences to all 9 strains markedly decreased in the 2- to 3-months-old lamb group and increased again in the adult sheep group. Also, adult sheep sera neutralized a larger number of rotavirus strains than 2- to 3-months-old lamb sera. The highest neutralizing antibody titers and prevalences were found to strains B223 and K923, representing serotype G10, to strain RRV, representing serotype G3, and to strain NCDV, representing serotype G6, indicating that these could be the predominant 3 rotavirus serotypes in Spanish sheep. The rotavirus serotypes infecting sheep observed by us differ from those described for cattle, where G6 is the most prevalent serotype followed by G10, and G3 has been seldom found. Very low prevalences were observed for strains WA and OSU representing serotypes G1 and G5 respectively, suggesting that they probably do not infect sheep and neutralizing antibodies found are derived from heterotypic responses to other serotypes. Intermediate prevalences and titers were found to strains UK (serotype G6), 69M (serotype G8) and WI61 (serotype G9). Neutralizing antibodies distinguished between different strains sharing their VP7 specificity: B223 and K923, a bovine and an ovine serotype G10 strains, and NCDV and UK, two serotype G6 bovine rotavirus strains with different VP4 antigen.

Aging↗
PubMed1997

[Role of group B streptococcus serotype V in materno-fetal infections].

BACKGROUND: The classification of serogroup B streptococci in serotype is based on the structural differences of capsular polysaccharides and on presence or absence of a protein c antigen. They are classified as Ia, Ia/c, Ib/c, II, II/c, III, IV and V. The serotype V, unknown in 1970, seems emerging, and is placed in third position of frequency in some American studies. We have therefore decided to evaluate its frequency in Paris. POPULATION AND METHODS: In a population of 137 pregnant women and 60 neonates carrying streptococcus of serogroup B, the serotype was systematically determined using the test "Group B streptococcus serotyping test" (Dako, Danemark). RESULTS: In the pregnant women population, 12% of the isolated strains were of serotype V, 26% of serotype III, 15% of serotype II, 14% of serotype Ia, and 21% could not be typed. In neonates, it represented 15% of the isolates and took place after the serotype Ia (20%), the serotype III (18%) and the serotype II (15%). None of the neonates had early- or late-onset disease. They were only colonized. Only one mother exhibited, during the per-partum, a positive blood culture with a streptococcus group B of serotype V. CONCLUSION: These results confirm, in Paris, the importance of this serotype previously observed in foreign studies. It represents 11 to 15% of the isolated streptococcus group B in the neonates and can cause early or late-onset disease. However, larger studies are needed to evaluate the exact risk of pathology for the serotype V and its significance in neonatal infectious disease.

Female↗
PubMed1993

Distinct yearly change of serotype distribution of human rotavirus in Thailand as determined by ELISA and PCR.

A total of 241 group A rotavirus-positive stool samples collected from diarrhoeic patients in Thailand between July 1988 and June 1991 were characterized for their serotypes by enzyme-linked immunosorbent assay (ELISA) using serotype-specific monoclonal antibodies and by a polymerase chain reaction (PCR). In July 1988-June 1989, serotype 1 was the most prevalent (63.4%), followed by serotype 4 (11.0%) and serotype 2 (8.5%). In July 1989-June 1990, 59.8% were serotype 1, 24.3% were serotype 2, and 6.1% were serotype 3. In contrast, in July 1990-June 1991, serotype 3 was detected in the highest frequency (40.5%), 29.9% were serotype 1, and 27.3% were serotype 2. Thus, a distinct yearly change of serotype distribution of rotavirus in Thailand was observed in the three consecutive years. In particular, it was of note that the prevalence of serotype 3 greatly increased, in contrast to the previous studies in which almost no serotype 3 rotaviruses were detected in the years 1983-8 in Thailand.

DNA, Viral↗
PubMed1997

Vaccination against colonizing bacteria with multiple serotypes.

Conjugate vaccines protect vaccinated individuals against both disease from and nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae. Protection is specific to the capsular serotype(s) included in the vaccine. This specificity has raised concern that vaccination against particular ("targeted") serotypes may cause an increase in carriage of (and diseases attributable to) nontargeted serotypes. I analyzed a mathematical model designed to predict the factors affecting, and the expected extent of, such replacement in the host population. The conditions for competitive exclusion and coexistence of serotypes under mass vaccination are derived, and the equilibrium carriage of target and nontarget serotypes is determined under various ecological and epidemiological conditions. The eradication threshold for a target serotype in the presence of competing, nontarget serotypes is always lower for serotype-specific than for bivalent vaccines. In a two-serotype model, the increase in the prevalence of any single nontargeted serotype due to vaccination will not exceed the total reduction in prevalence of a targeted serotype. However, if three or more serotypes interact epidemiologically, vaccination against one type may increase carriage of a second more than it decreases carriage of the first. Carriage of a second serotype against which the vaccine offers only partial protection may initially increase and then decrease as a function of vaccine coverage. I discuss the extent to which these theoretical results can account for existing data on serotype replacement after vaccination against H. influenzae and their implications for vaccine policy.

Bacterial Vaccines↗
PubMed2004

Emergence of penicillin-nonsusceptible Streptococcus pneumoniae clones expressing serotypes not present in the antipneumococcal conjugate vaccine.

BACKGROUND: Penicillin-nonsusceptible Streptococcus pneumoniae isolates are confined mainly to a few serogroups. Capsular transformation may serve as a mechanism for spreading antibiotic resistance to new serotypes. METHODS: Antibiogram and molecular typing, by pulsed-field gel electrophoresis (PFGE), were performed on 46 nasopharyngeal and middle ear fluid (MEF) isolates expressing serotype 11A, 45 MEF isolates expressing serotype 15B/C (recovered during 1998-2003 from Israeli children <5 years old), and 57 MEF isolates expressing serotype 19F (recovered during 1998-2001 from Costa Rican children <7.5 years old). RESULTS: PFGE patterns showed that 49 (86%) of 57 serotype 19F isolates and 19 (41%) of 46 serotype 15B/C isolates were closely related. The vast majority of these isolates (80% of serotype 19F and 100% of serotype 15B/C isolates) were nonsusceptible to penicillin. Multilocus sequence typing (MLST) data show that the serotype 15B/C isolates belonged to the ST346 cluster, whereas the serotype 19F isolates were a single-locus variant of ST346. For serotype 11A isolates, PFGE patterns and MLST analysis showed that 8 (80%) of the 10 penicillin-nonsusceptible isolates belonged to a single clone--namely, ST156--which was identical to the international Spain9V-3 clone. CONCLUSIONS: Penicillin-nonsusceptible pneumococcal clones of serotypes not related to those included in the 11-valent conjugate vaccines may derive from capsular transformation of vaccine-related serotypes. Of particular concern was the detection of serotype 11A variants of the successful international Spain9V-3 clone. This phenomenon, although seemingly rare at present, can have implications for the long-term effectiveness of the conjugate vaccines.

Child↗
PubMed1998

Serotype distribution of invasive group B streptococcal isolates in Maryland: implications for vaccine formulation. Maryland Emerging Infections Program.

Invasive group B streptococcal (GBS) infection is a major health problem among infants and adults. The formulation of GBS vaccines depends on knowledge of the GBS serotype distribution. Serotype V GBS infection appears to have recently emerged, suggesting that the serotype distribution changes over time. GBS isolates from 210 pediatric patients, 23 pregnant women, and 314 nonpregnant adults with invasive infection in Maryland were studied. The predominant serotypes from infants with early-onset disease were as follows: serotype III, 38% of isolates; serotype Ia, 36%; serotype V, 13%; and serotype II, 11%. Although the majority (60%) of isolates among infants with late-onset infection were serotype III, serotype Ia (23%) was also common. The predominant serotype among isolates from nonpregnant adult patients was serotype V, accounting for 29% of the isolates. The serotype distribution differs between pediatric patients and adults and is changing over time. The inclusion of a relatively small number of serotypes in a GBS vaccine could provide protection against the vast majority of isolates.

Adult↗
PubMed1998

Serotyping of HIV type 1 infections: definition, relationship to viral genetic subtypes, and assay evaluation. UNAIDS Network for HIV-1 Isolation and Characterization.

V3 serotyping refers to a system based on binding of antibody in patient sera to V3-loop peptides derived from HIV-1 env genetic subtypes. The V3x serotype represents reactivity of serum from an HIV-1-infected patient (regardless of viral genetic subtype), which reacts preferentially to a V3 peptide derived from the X subtype sequence. We have classified HIV-1 serotypes, determined the relationship between the HIV-1 V3 serotypes and viral genetic subtypes in a large study (n = 125), and evaluated the performance of three different V3 peptide-binding assays. Seven HIV-1 V3 serotypes were identified: A, B, B-Br, B-Th, C, D, and E. Serotypes B-Br and B-Th represent sera that react specifically to peptides derived from Brazilian B (B-Br, GWGR) and Thai B (B-Th, GPGQ) strains. The HIV-1 V3 B, C, and E serotypes correlated closely with their viral env genetic subtypes; 19-26 of 32 B sera (59-79%), 3-4 of 4 C sera (75-100%), and 19-22 of 23 E sera (83-96%) were identified as serotypes B, C, and E, respectively. In contrast, two major V3 serotypes were classified in A sera: A (14-18 of 36 [40-50%]) and C (12-19 of 36 [33-54%]). Similarly, two major V3 serotypes were classified in D sera: B (6-10 of 20 [30-50%]) and D (9-12 of 20 [45-60%]). Serotyping of subtype E sera showed the best concordance with genetic subtypes by all assays. Overall, HIV-1 V3 serotyping produced consistent results among three laboratories. However, HIV-1 V3 serotypes do not distinguish all HIV-1 genetic subtypes. The relative biological significance of the V3 serotypes remains to be elucidated.

Amino Acid Sequence↗
PubMed1997

Prevalence of serotype D in Cryptococcus neoformans isolates from HIV positive and HIV negative patients in Italy.

Cryptococcus neoformans strains isolated from 207 HIV positive and HIV negative patients hospitalized in Northern Italy were serotyped by slide agglutination. One Brazilian HIV negative woman was infected by var. gattii serotype B and all the other patients by var. neoformans, serotype D in 71%, serotype A in 24.6% and serotype AD in 3.4%. No difference was observed between subjects with serotypes A and D in HIV coinfection, exposure categories for AIDS, age, sex, and CD4 count of HIV positive patients. Meningeal and respiratory tract involvements and prostatic reservoir occurred with comparable frequency in AIDS patients infected by serotypes A and D. Skin lesions were observed only in serotype D infections, occurring in 12.6% of HIV positive and 58.3% of HIV negative patients infected by this serotype. Serotype A was found less susceptible to fluconazole than serotype D: 53.7% of serotype A strains had a MIC > or = 25 micrograms ml-1 compared to 17.7% of the serotype D isolates. On the other hand, both serotypes were highly susceptible to itraconazole.

Adolescent↗