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PubMed1999

Serological characterization of Actinobacillus pleuropneumoniae serotype 2 strains by using polyclonal and monoclonal antibodies.

The antigenic differences between strains of serotype 2 of both biotypes I and II of Actinobacillus pleuropneumoniae were studied by using several serological techniques. Monoclonal antibodies (MAbs) against A. pleuropneumoniae biotype I serotype 2 were produced by fusion of spleen cells of BALb/c mice immunized with whole-cell (WC) suspension with SP2/O-Ag14 murine myeloma cells. Desirable MAbs were selected by enzyme-linked immunosorbent assay (ELISA) using WC as antigen. MAbs MK-7 and MK-10 identified multiple bands of lipopolysaccharide in Western-blot. Treatment of WC with proteinase K and sodium periodate indicated that both MAb binding sites were carbohydrates in nature. In both ELISA and Western-blot, MAbs MK-7 and MK-10 recognized only biotype I serotype 2 isolates. Neither MAb MK-7 nor MK-10 reacted with reference strains of remaining serotypes of A. pleuropneumoniae and other Gram-negative bacteria tested. The results obtained with various serological tests showed that strains of serotype 2 biotype I shared antigenic determinants with strain N-282 of serotype 2 biotype II, but not with strain N-273 of serotype 1 biotype II. It is suggested that data obtained from this study may be helpful in the development of specific serotyping and serodiagnostic reagents of A. pleuropneumoniae strains.

Actinobacillus pleuropneumoniae↗
PubMed1989

Electropherotyping of plasmid DNA of different serotypes of Shigella flexneri isolated in Bangladesh.

One hundred and twenty-five Shigella flexneri strains, isolated during January-December 1984, at the Dhaka treatment centre of the International Centre for Diarrhoeal Disease Research, Bangladesh, were serotyped using absorbed rabbit antisera specific for all type- and group-factor antigens, as well as a group of ten mouse and rat monoclonal antibodies. Electropherotypes of the plasmid deoxyribonucleic acid (DNA) were also determined. S. flexneri 2a was the predominant serotype followed by 3b, 1a, and 2b. The recently described E1037 antigen was also found in three strains of S. flexneri serotype 6. Electropherotyping of the plasmid DNA showed that three plasmids of approximately 140, 2.7, and 2 megadalton (MDa) were present, respectively, in 97, 97 and 94% of the 125 strains. Additional plasmids of various other sizes were also present in different serotypes except in serotype 2a. The additional plasmids again appeared to be specific for that particular serotype. For example, all 12 strains of S. flexneri 2b harboured an additional plasmid of approximately 1 MDa. Thus, electropherotyping of plasmid DNA of different serotypes of S. flexneri might be useful to differentiate S. flexneri from other species of Shigella and in identifying different serotypes of S. flexneri. Therefore, the common plasmids, plus the additional plasmids, could be used to identify epidemic, as well as sporadic, subclones of S. flexneri strains.

Bangladesh↗
PubMed2004

Blood invasiveness of Salmonella enterica as a function of age and serotype.

We explored the dual influence of the patient's age and the infecting serotype on the blood invasiveness patterns of non-Typhi Salmonella enterica (NTS). Blood invasiveness ratio (BIR) was calculated as the ratio between the number of blood and blood + stool isolates. Analysis of 14,951 NTS isolates showed that the BIR increased drastically above the age of 60 years, reaching levels 3.5-7 times higher compared to age group < 2 years. Different patterns of age-related invasiveness were observed for the five most common NTS serotypes (Enteritidis, Typhimurium, Virchow, Hadar, Infantis). Among children < 2 years, the BIR was highest for serotype Virchow and lowest for serotype Hadar, while in persons > or = 60 years it was highest for serotypes Enteritidis and lowest for serotype Infantis. The tendency of NTS serotypes to invade the bloodstream was significantly influenced by the patient's age, however the impact of age differed for various NTS serotypes.

Adolescent↗
PubMed1999

Serotype distribution and secretory acid proteinase activity of Candida albicans isolated from the oral mucosa of patients with denture stomatitis.

Denture stomatitis is the most common form of oral Candida infection in humans. In the current study, the distribution of Candida albicans serotype A and B as well as the activity of the secreted acid proteinase were determined in clinical isolates from patients with denture stomatitis. It was found that 70% of individuals with clinical signs of denture stomatitis exhibited fungal growth, with C. albicans representing the most frequently isolated species (75%). Of the C. albicans isolates, 75% were serotype A and 25% were serotype B, representing a significant increase of serotype B compared to a control group of non-denture-wearing HIV-seronegative individuals with oral candidiasis, but no significant difference compared with isolates from HIV-seropositive patients, who also exhibited a high percentage of serotype B. The mean secretory acid proteinase activity of C. albicans isolates from denture stomatitis patients (2796 +/- 819 U/l) was statistically not different from the mean secretory acid proteinase activity in non-denture-wearing HIV-seronegative individuals (2324 +/- 1487 U/l). Both values were significantly lower than the mean secretory acid proteinase activity of C. albicans from HIV-seropositive individuals (4256 +/- 2372 U/l). No correlation exists between the C. albicans serotype and the amount of secreted acid proteinase, indicating that serotype and secretory acid proteinase expression are two independent pathogenetic factors in oral candidiasis. These results indicate that there seems to be strain selection for C. albicans serotype B in denture stomatitis. These results further indicate that increased secretion of the acid proteinase seems to be of pathogenetic significance in the candidiasis of HIV-seropositive patients but not in denture stomatitis. Nevertheless, the secretory acid proteinase is likely to be an important pathogenetic factor also in denture stomatitis, where an increased secretion of the acid proteinase may not be required because of decreased salivary flow and a low pH under the denture, which will result in a high enzymatic activity.

Adult↗
PubMed2002

A potential new serotype of Riemerella anatipestifer isolated from ducks in Thailand.

Eighty isolates of Riemerella anatipestifer representing 71 outbreaks of riemerellosis in Thailand between 1994 and 1999 were serotyped using the gel diffusion precipitin test. Based on the precipitation patterns, 25 serological profiles containing one to three antigenic determinants were recognized. Heat-stable antigens of the organism reacted with antisera raised against 16 known serotypes and an untypable strain 698/95. The most prevalent serotype appeared to be serotype 7, followed by serotypes 5, 10, 21 and 1. Further study demonstrated that the untypable strain probably represents a new serotype. Analysis of the polymerase chain reaction-amplified rrs genes for restriction fragment length polymorphisms verified the inclusion of strain 698/95 within the species R. anatipestifer and supported earlier work excluding strain 670/89, which had originally been designated the reference strain of serotype 20. Therefore, it is suggested that the strain 698/95 could be adopted as a replacement for the reference strain of serotype 20. Attention should be paid to strains with multiple antigenic factors as they may be useful for the preparation of vaccines.

Animals↗
PubMed2001

Isolation of a Cryptococcus neoformans serotype A MATa strain from the Italian environment.

Cryptococcus neoformans is a heterothallic basidiomycete which possesses a bipolar mating system based on two mating type alleles, MATa and MATalpha. In the type variety, C. neoformans var. neoformans, both mating types have been found among strains of one serotype, serotype D, whereas only MATalpha was identified after extensive survey of serotype A strains. Serotype A MA Ta appeared to be extinct or to exist only in a vestigial, non-functional form. We report the isolation of a C. n. var. neoformans serotype A MATa strain from the Italian environment. The strain was serotyped by slide agglutination test, genotyped by polymerase chain reaction (PCR) fingerprinting using the (GACA)4 primer, and its haploid state was determined by flow cytometry. The mating type was identified by PCR amplification of the pheromone a gene. In addition, the amplification of the four STE20 alleles, specific for the mating type of serotypes A and D, showed that the strain contains only the MATa locus. By crossing experiments the strain was found to be fertile. The interest in the finding of this fertile isolate is related to the possibility to construct a congenic pair of serotype A MATa/MATalpha strains to be used in genetic and pathogenesis studies.

Cryptococcus neoformans↗
PubMed1995

A single nine-amino acid peptide induces virus-specific, CD8+ human cytotoxic T lymphocyte clones of heterogeneous serotype specificities.

It is generally accepted that virus-specific CD8+ cytotoxic T lymphocytes (CTLs) recognize nine-amino acid peptides in conjunction with HLA class I molecules. We recently reported that dengue virus-specific CD8+ CTLs of two different serotype specificities, which were established by stimulation with dengue virus, recognize a single nine-amino acid peptide of the nonstructural protein NS3 of dengue virus type 4 (D4V) in an HLA-B35-restricted fashion. To further analyze the relationships between the serotype specificities of T cells and the amino acid sequence of the recognized peptides, we examined the ability of this viral peptide D4.NS3.500-508 (TPEGIIPTL) to stimulate T lymphocytes of an HLA-B35-positive, dengue virus type 4-immune donor. Peptide stimulation of the PBMC generated dengue virus-specific, HLA-B-35-restricted CD8+ CTL clones. These clones lysed dengue virus-infected autologous cells, as well as autologous target cells pulsed with this peptide. Four patterns of dengue virus serotype specificities were demonstrated on target cells infected with dengue-vaccinia recombinant viruses or pulsed with synthetic peptides corresponding to amino acid sequences of four dengue virus serotypes. Two serotype-specific clones recognized only D4V. Three dengue virus subcomplex-specific clones recognized D1V, D3V, and D4V, and one subcomplex-specific clone recognized D2V and D4V. Three dengue virus serotype-cross-reactive clones recognized D1V-D4V. Thus, a single nine-amino acid peptide induces proliferation of a heterogeneous panel of dengue virus-specific CD8+ CTL clones that are all restricted by HLA-B35 but have a variety of serotype specificities. Peptides that contain a single amino acid substitution at each position of D4.NS3.500-508 were recognized differently by the T cell clones. These results indicate that a single epitope can be recognized by multiple CD8+ CTLs that have a variety of serotype specificities, but the manner of recognition by these multiple CTLs is heterogeneous.

Amino Acid Sequence↗
PubMed2002

Seroepidemiologic studies of serotype VIII group B Streptococcus in Japan.

Levels of antibody to serotype VIII group B Streptococcus (GBS) were surveyed in serum samples from 583 pregnant women, from 461 neonates born to these women, and from 4 mother-and-neonate pairs with early-onset serotype VIII sepsis. Colonization by serotype VIII GBS was associated with significantly higher serum concentrations of serotype-specific antibodies (geometric mean [GM], 5.53 micro g/mL), compared with both noncolonization (1.53 micro g/mL) and colonization with other serotypes (2.19 micro g/mL). There was excellent correlation between antibody levels in mothers and those in their neonates. The prevalence of positive antibody levels, when arbitrarily defined, according to antibody levels in neonatal sepsis (GM, 0.49 micro g/mL) as >1.0 micro g/mL, was 58% of all pregnant women and 85% of the women colonized by serotype VIII. This high serotype prevalence may explain, at least in part, why serotype VIII causes early-onset neonatal disease at rates lower than those which would be expected on the basis of its prevalence in mothers in Japan who are colonized by GBS.

Adult↗
PubMed2003

Clonal relationships between invasive and carriage Streptococcus pneumoniae and serotype- and clone-specific differences in invasive disease potential.

By use of multilocus sequence typing, Streptococcus pneumoniae isolates causing invasive disease (n=150) were compared with those from nasopharyngeal carriage (n=351) among children in Oxford. The prevalence of individual clones (sequence types) and serotypes among isolates from invasive disease was related to their prevalence in carriage, and an odds ratio (OR) for invasive disease was calculated for the major clones and serotypes. All major carried clones and serotypes caused invasive disease, although their ability to do so varied greatly. Thus, 2 serotype 14 clones were approximately 10-fold overrepresented among disease isolates, compared with carriage isolates, whereas a serotype 3 clone was approximately 10-fold underrepresented. The lack of heterogeneity between the ORs of different clones of the same serotype, and analysis of isolates of the same genotype, but different serotype, suggested that capsular serotype may be more important than genotype in the ability of pneumococci to cause invasive disease.

Carrier State↗
PubMed2004

Association of clinical signs and symptoms with pneumococcal acute otitis media by serotype--implications for vaccine effect.

BACKGROUND: Clinical symptoms and signs in acute otitis media (AOM) may differ depending on the various pneumococcal serotypes causing the disease. Alteration in clinical presentation of AOM could be expected after wide-scale pneumococcal vaccinations if there were considerable differences between vaccine serotypes and nonvaccine serotypes. METHODS: In this study, data from 831 children in the control arm of the Finnish Otitis Media Vaccine Trial were used. The children were followed up prospectively in 8 study clinics from 2 to 24 months of age. If AOM was diagnosed, myringotomy was done, and middle ear fluid was aspirated for bacterial culture. Clinical symptoms and signs of AOM were routinely recorded on structured case report forms. RESULTS: Consistent with previous studies, 60% of pneumococcal episodes were caused by vaccine serotypes. There were no major differences between the clinical presentations of AOM due to different serotypes or serotype categories. However, earache was more often associated with AOM caused by vaccine and cross-reactive serotypes, compared with AOM caused by non-vaccine-related serotypes (42% vs. 29%; odds ratio, 1.66; 95% confidence interval, 1.02-2.70). CONCLUSIONS: Introduction of the currently available pneumococcal conjugate vaccine is unlikely to result in a remarkable alteration in the clinical presentation of pneumococcal AOM in infants.

Acute Disease↗
PubMed2004

Antimicrobial resistance and serotype prevalence of Salmonella isolated from dairy cattle in the southwestern United States.

Mature dairy cattle were sampled over a 2-year period (2001-2002) on six farms in New Mexico and Texas. Fecal samples (n = 1560) were collected via rectal palpation and cultured for Salmonella, and one isolate from each positive sample was serotyped. Three isolates of each serotype, with the exception of Salmonella Newport (n = 12), were examined for susceptibility to 17 antimicrobial agents. Twenty-two different serotypes were identified from a total of 393 Salmonella isolates. Montevideo was the predominant serotype (27%) followed by Mbandaka (15%), Senftenberg (11.4%), Newport (6.4%), Anatum (4.8%), and Give (4.8%). Salmonella Typhimurium and Dublin, two frequently reported serotypes, accounted for only 1% of the observed serotypes in this study. Sixty-four percent of the serotypes were susceptible to all 17 antimicrobials, 14% were resistant to a single agent, and 22% were multiresistant (2-11 types of resistance). All isolates tested were susceptible to amikacin, apramycin, imipenem, ceftriaxone, nalidixic acid, and ciprofloxacin. The most frequent types of resistance were to sulfamethoxazole, tetracycline, streptomycin, kanamycin, chloramphenicol, and ampicillin (ranging from 8.9 to 22.4%). Serotypes demonstrating multiple resistance included Dublin and Give (resistant to three or more antibiotics), Typhimurium (resistant to five antibiotics), and Newport (four and two isolates resistant to six and nine antibiotics, respectively). Class 1 integrons were present in only two Salmonella Dublin isolates and one Salmonella Newport isolate. The most prevalent resistance patterns observed in this study were toward antimicrobial agents commonly used in cattle, while all Salmonella isolates were susceptible to ceftriaxone and ciprofloxacin, antibiotics used in human medicine.

Animals↗
PubMed1979

Heterogenity of serotypes of Neisseria meningitidis that cause endemic disease.

Three collections of strains of Neisseria meningitidis that caused meningococcal disease during nonepidemic periods were serotyped to determine whether serotypes that cause endemic disease are more heterogeneous than those responsible for epidemic disease. Thirty-four strains isolated from pediatric patients in Houston, Texas, from February 1977 to March 1978 were of three separate serogroups and 11 serotypes; 27 contemporary (1977-1978) strains from predominantly military populations, obtained nationwide, were of six serogroups and six serotypes, while 11 strains isolated at military posts in the southwest United States from 1970 through 1976 were of four serogroups and five serotypes. Between 9% and 20% of the strains were nontypable, while type II strains which were responsible for the epidemics in the Northern and Western Hemispheres earlier in the 1970's, accounted for only 20%-44% of the strains. In contast to epidemics, which appear to be caused by a single serotype, endemic meningococcal disease appears to be caused by a broad, heterogeneous distribution of serotypes. Thus, development of a serotype-specific vaccine may have limited application to the prevention of endemic meningococcal disease.

Adult↗
PubMed1982

Lipopolysaccharide and high-molecular-weight polysaccharide serotypes of Pseudomonas aeruginosa.

The serotype distribution of bacteremic and nonbacteremic clinical isolates of Pseudomonas aeruginosa in relation to the Fisher immunotyping scheme, the International Antigenic Typing System (IATS), and high-molecular-weight polysaccharide determinants was investigated. Of 281 bacteremic isolates, 273 (97.2%) were serotyped by one of the seven IATS specificities that correspond to a Fisher lipopolysaccharide/high-molecular-weight polysaccharide specificity. In contrast, these seven serotypes accounted for only 68.5% of the 124 nonbacteremic clinical isolates. Review of the reported serotype distribution of P. aeruginosa isolates in Europe further supported the finding of a limited serotype distribution among bacteremic clinical isolates. Fifteen of the 17 IATS serotypes were found among all of the strains of P. aeruginosa serotyped, an indication that most of the IATS serotypes are present in the United States. Thus, only certain lipopolysaccharide immunotypes of P. aeruginosa occur as clinical bacteremic isolates, and a multivalent, high-molecular-weight polysaccharide vaccine directed at the lipopolysaccharide type determinants of P. aeruginosa has potential usefulness.

Agglutination Tests↗
PubMed1984

Serotypic similarity and diversity of rotaviruses of mammalian and avian origin as studied by plaque-reduction neutralization.

A total of 16 different strains of rotavirus derived from seven mammalian species (four each from human and porcine species, two each from equine and simian species, and one each from canine and bovine species) and two avian species (one each from turkeys and chickens) were examined in plaque-reduction neutralization tests. Seven antigenically distinct serotypes were established on the basis of a greater than or equal to 20-fold difference between titers of homologous and heterologous reciprocal neutralizing antibodies. Serotypes 1 (strain Wa) and 2 (strain DS-1) were recovered only from humans. Serotype 3 included human rotavirus strain WALK 57/14, rhesus monkey rotavirus strain MMU18006 , vervet monkey rotavirus strain SA-11, dog rotavirus strain CU-1, and horse rotavirus strain H-2. The newly established serotype 4 was identified in both humans (strain St. Thomas no. 4) and pigs (strains Gottfried , SB-1A, and SB-2). Porcine (strain OSU ) and equine (strain H-1) rotaviruses made up a possible fifth serotype. Bovine rotavirus (strain NCDV) constituted a sixth serotype, and chicken rotavirus (strain Ch 2), which had a prime-strain relation with turkey rotavirus (strain Ty 1), was designated serotype 7. A surprising observation that emerged from this study was the existence of a rotavirus (porcine strain SB-1A) bridging serotypes 4 and 5.

Animals↗
PubMed1996

Invasive group B streptococcal disease: the emergence of serotype V.

Group B streptococci (GBS) cause invasive disease in neonates, pregnant adults, and nonpregnant adults with underlying or chronic disease. Previous studies found capsular serotypes Ia, Ib, II, and III cause invasive disease. Prospective population-based surveillance of invasive GBS disease was done from June 1992 to June 1993 in metropolitan Atlanta: 279 patients had invasive disease. Of these, 43% were < or = 6 months old, and 57% were adults. The incidence among all adults was 7.7/100,000/year, 33% higher than in 1989-1990 (P < .01). The incidence in nonpregnant adults was 5.9/100,000/year, 37% higher than in 1989-1990 (P < .02). Serotyping of 178 patient isolates revealed that 34% had GBS serotype Ia or Ia/c, 8% had Ib/c, 6% had II or II/c, 29% had III, 0% had IV, 21% had V, and 2% were nontypeable. Serotype V was recovered from all groups and was the most common serotype from nonpregnant adults. Serotype V isolates appeared to be highly related genetically. The increasing incidence of GBS disease in adults, the changing distribution of serotypes, and the emergence of serotype V will impact vaccine strategies.

Adolescent↗
PubMed2002

Antimicrobial susceptibility and pneumococcal serotypes.

The increase in antibiotic resistance and the possible changes in serotype prevalence as a consequence of a new conjugated vaccine have contributed to renewed interest in the study of pneumococcal serotypes and their antibiotic resistances. Spain still has one of the highest penicillin resistance rates, but in the past 4-5 years a slight decrease has been observed. The level of resistance has not increased either, 12.7% of the 11 165 isolates studied showed high-level penicillin resistance but 94% of these had an MIC of only 2 mg/L. Serotypes 6, 9, 14, 19 and 23 included 83% of the penicillin-resistant pneumococci; the remaining 17% belonged to 18 different serotypes. We analysed these minor penicillin-resistant serotypes in view of their potential increase following a possible child vaccination programme. Four of these serotypes (11, 15, 21 and 35) were the most prevalent, and among them serotype 15 was particularly frequent with >50% of its strains resistant. The effective control of these minor penicillin-resistant serotypes should be based on continuous surveillance of pneumococcal epidemiology.

Drug Resistance, Bacterial↗
PubMed1976

The dynamics of streptococcal infections in a defined population of children: serotypes associated with skin and respiratory infections.

Serial observations including cultures of the upper respiratory tract and of infected skin lesions and streptococcal antibody determinations were made over a two-year period in a semi-closed population of children between 10 months and 15 years of age. There was a high prevalence of group A streptococci in nose and throat cultures and of skin lesions containing these organisms. Almost 90% of the study population developed streptococcal impetigo during the study period. A slightly higher proportion of males than females developed skin infection but there was no relationship to age. Impetigo was observed throughout the calendar year, exceeding 12% of child-visits in one winter month, but was generally more common in the summer and fall. Conversely, group A streptococci were more often isolated from nose and throat cultures in the winter months. The increase in recovery of streptococci from nose and throat cultures lagged behind the increase in streptococcal impetigo and continued into the winter months, when the prevalence of impetigo had declined. Calculation of ratios for individual streptococcal serotypes isolated from different body sites revealed a clear cut distinction between "respiratory" and "impetigo" serotypes, with respect to both prevalence and acquisition rates. Respiratory serotypes were more commonly isolated in the winter and impetigo serotypes in the summer and fall. Significant antibody responses to extracellular antigens of the streptococcus were documented for pharyngeal acquisitions of both impetigo and respiratory serotypes and for skin lesions associated with impetigo serotypes. Group A streptococcal serotypes may be divided into three categories on the basis of their human pathogenicity for body sites: some with the potential for respiratory infection, others with the potential for skin infection and a few unusual serotypes with the potential for infecting both sites.

Age Factors↗
PubMed1995

Adenoviral ocular isolates demonstrate serotype-dependent differences in in vitro infectivity titers and clinical course.

The purpose of this study was to evaluate clinical ocular adenoviral isolates for differences among and within serotypes with respect to in vitro infectivity titers and clinical course. The study design included a retrospective chart review and the determination of in vitro infectivity titers (TCID90s) of 90 clinical ocular isolates of various adenoviral serotypes. Adenovirus serotype 8 (AD8) was recovered in significantly greater numbers of patients in the second week of infection compared to all other serotypes (p < 0.002). AD3 and AD4 presented with the highest infectivity titers during the first week of acute infection. Up to 4 logs of variation was demonstrated in TCID90s among isolates of the same serotype. Among the clinical parameters studied, eyelid edema was significantly more common among AD8-infected patients as compared to all other serotypes (p < 0.04). For the first time, specific, but limited serotype differences with respect to infectivity titers and clinical course were demonstrated for adenoviral ocular isolates. Important variations in isolate virulence within a given serotype were also observed.

Adenovirus Infections, Human↗