Study of "group" expression of mRNA of the ion transporters ATP1B1, NHE1 and NKCC1, beta-actin, glycerophosphosphate dehydrogenase, proteins regulating proliferation and apoptosis of p53, Bcl-2, IL-2 and hSGK kinase at the prereplicative stage of human lymphocyte activation

Previously, we found no segregation in F2 obtained from crosses between two Dileptus anser clones differing (under the same culture conditions) in their serotypes, i.e. in their immobilization antigens (i-antigens); indeed, all the F2 clones had mixed, i.e. hybrid serotype, being immobilized simultaneously with both immune sera developed against either parental clone (Uspenskaya, Yudin, 2000). Presently, experiments were carried out to see if this unusual phenotype would be re-expressed after a temporary switching off. To switch off both expressed i-antigens, serotype transformation was induced in the F2 clones by shifting the culture temperature from 25 to 17 degrees C. Two weeks later, when the clones returned to the initial temperature conditions, each of them was seen to re-express both parental i-antigens. This result is discussed with reference to the role of i-antigens in regulation of their own expression as has been suggested by some authors.     

Mating types in the ciliate Dileptus anser. Shortening of maturation period after micrurgical bisection of exconjugant cells

In many ciliates, young exconjugant clones demonstrate sexual immaturity: they are not able to conjugate with mature cells of complementary mating types (MTs). After several scores of cell divisions, a short period of adolescence (partial maturity) commonly occurs followed by maturation, after which these cells are able to conjugate with cells of other, i.e. complementary, MTs again. Tavrovskaja (1981) reported a significant reduction in the maturity period in Dileptus anser clones, grown from exconjugant ciliates regenerated from small cell fragments. To verify this, in the present study exconjugant D. anser cells were bisected with glass needle after 3 to 4 cell divisions following conjugation. The same procedure was performed with survived and regenerated cells on the 2nd and 3rd days. The clones thus obtained were cultivated, and their ability to mate with each of the three standard clones of MT I, II and III was tested week by week. Indeed, in 22 F1 clones from cross N 7C (MT I) x N 2 (MT II) the immaturity period was reduced 1.4-3.4-fold (2.18 in average) after a threefold bisection, as compared with that in intact subclones. Similarly, in 27 F1 clones from cross N 20 (MT I) x N 14 (MT II) this period was shortened 1.6-3.0-fold (2.19 in average). 12 of these clones showed a 0.9-2.4-fold (1.53 in average) reduction after a single bisection, and 1.6-2.8 (2.12 in average) after a threefold operation. Thus, micrurgical fragmentation of young exconjugant cells can be used to accelerate maturation in D. anser.     

Mating types in the ciliate Dileptus anser. Inheritance and genetic determination

Hybridological analysis of mating types (MTs) has been first made for the lower ciliate Dileptus anser. Clones of an initially unknown genotype belonging to three MTs (MT I, MT II and MT III), characteristic of D. anser, were isolated from natural reservoirs and further used for crosses. In one group crosses, synclonal inheritance and typical Mendelian behaviour of the character were observed over sexual generations of ciliates. The results suggest that MTs in D. anser may be directly controlled by a single mat locus with three alleles showing peck-order dominance (mat1 > mat2 > mat3). In other words, cells with mat1/mat1, mat1/mat2 and mat1/mat3 genotypes belong to MT I, those with mat2/mat2 and mat2/mat3, and the mat3/mat3 belong to MT II and MT III, respectively. Sexually mature exconjugant clones stably retain their MTs corresponding to their genotypes on vegetative reproduction. The progeny of other group crosses showed various deviations from typical Mendelian behaviour of the character. In some cases, standard Mendelian ratios were more or less violated. Most typical was instability of differentiation for MT in maturing exconjugant clones. Shortly after their maturation, the majority of clones change their MT, rather frequently more than once, although the finally established MT is stably inherited afterwards, during vegetative reproduction. When unstable, exconjugant clones can successively express two or even three MTs characteristic of this species, including MTs that should not have been expected on the basis of parental genotypes available in a given cross. It looks likely that the mat locus in D. anser is complex and multipotential; it is inherited as a whole providing for expression of any MT characteristic of the species (in this respect bearing similarity with Tetrahymena thermophila). Other mechanisms, epigenetic in particular (Nanney, 1958), determine the final expression of one of the three MT potentialities by a given exconjugant clone. Stable, persistent functioning of these mechanisms ensures a stable differentiation for MT and Mendelian behaviour of the character in sexual generations and in crosses. Any disturbances in differentiation control may trigger MT instability in maturing exconjugant clones and violation of regular Mendelian behaviour.     

Contribution of capsular and clonal types and beta-lactam resistance to the severity of experimental pneumococcal meningitis

We used a rabbit model to assess the effects of capsular serotype, genetic background and beta-lactam resistance on the course and severity of experimental meningitis. Meningitis was induced by five pneumococcal strains belonging to five different clones with known invasive potential: two serotype 3 strains (ST260(3) and Netherlands(3)-31 clones) and three serotype 23F strains with different beta-lactam susceptibility patterns (Spain(23F)-1 clone, Tennessee(23F)-4 clone and a double locus variant of the Tennessee(23F)-4 clone). Major differences in secondary bacteremia and mortality rates were observed between serotypes 3 and 23F, as were divergences in the CSF lactate, protein and lipoteichoic-teichoic acid concentrations. Minor differences in the CSF-induced inflammatory response were found among strains belonging to the same serotype. Our results suggest that capsular serotype might be the main factor determining the course and severity of pneumococcal meningitis and genetic background contributes to a lesser extent. The acquisition of beta-lactam resistance does not reduce the virulence of the invasive clones. Since five strains belonging to two serotypes were studied, our findings have to be confirmed with other pneumococcal serotypes.     

Single point mutations may affect the serotype reactivity of serotype G11 porcine rotavirus strains: a widening spectrum?

A panel of single and double neutralization-resistant escape mutants of serotype G11 porcine rotavirus strains A253 and YM, selected with G11 monotype- and serotype-specific neutralizing monoclonal antibodies (MAbs) to VP7, was tested in neutralization assays with hyperimmune sera raised against rotavirus strains of different serotypes. Escape mutants with an amino acid substitution in antigenic region A (amino acids [aa] 87 to 101) resulting in a residue identical or chemically similar to those present at the same positions in serotype G3 strains, at positions 87 for strain A253 and 96 for strain YM, were significantly more sensitive than the parental strains to neutralization with sera against some serotype G3 strains. Also, one YM antigenic variant (YM-5E6.1) acquired reactivity by enzyme-linked immunosorbent assay with MAbs 159, 57/8, and YO-1E2, which react with G3 strains, but not with the serotype G11 parental strain YM. Cross-adsorption studies suggested that the observed cross-neutralization by the G3-specific sera was due to the sera containing antibodies reactive with the parental strain plus antibodies reactive with the epitope(s) on the antigenic variant that mimick the serotype G3 specific one(s). Moreover, antibodies reactive with antigenic region F (aa 235 to 242) of VP7 might also be involved since cross-reactivity to serotype G3 was decreased in double mutants carrying an additional mutation, which creates a potential glycosylation site at position 238. Thus, single point mutations can affect the serotype reactivity of G11 porcine rotavirus strains with both monoclonal and polyclonal antibodies and may explain the origin of rotavirus strains with dual serotype specificity based on sequence divergence of VP7.     

Comparison of a Real-Time Multiplex PCR and Sequetyping Assay for Pneumococcal Serotyping

Background

Pneumococcal serotype identification is essential to monitor pneumococcal vaccine effectiveness and serotype replacement. Serotyping by conventional serological methods are costly, labour-intensive, and require significant technical expertise. We compared two different molecular methods to serotype pneumococci isolated from the nasopharynx of South African infants participating in a birth cohort study, the Drakenstein Child Health Study, in an area with high 13-valent pneumococcal conjugate vaccine (PCV13) coverage.

Methods

A real-time multiplex PCR (rmPCR) assay detecting 21 different serotypes/-groups and a sequetyping assay, based on the sequence of the wzh gene within the pneumococcal capsular locus, were compared. Forty pneumococcal control isolates, with serotypes determined by the Quellung reaction, were tested. In addition, 135 pneumococcal isolates obtained from the nasopharynx of healthy children were tested by both serotyping assays and confirmed by Quellung testing. Discordant results were further investigated by whole genome sequencing of four isolates.

Results

Of the 40 control isolates tested, 25 had a serotype covered by the rmPCR assay. These were all correctly serotyped/-grouped. Sequetyping PCR failed in 7/40 (18%) isolates. For the remaining isolates, sequetyping assigned the correct serotype/-group to 29/33 (88%) control isolates. Of the 132/135 (98%) nasopharyngeal pneumococcal isolates that could be typed, 69/132 (52%) and 112/132 (85%) were assigned the correct serotype/-group by rmPCR and sequetyping respectively. The serotypes of 63/132 (48%) isolates were not included in the rmPCR panel. All except three isolates (serotype 25A and 38) were theoretically amplified and differentiated into the correct serotype/-group with some strains giving ambigous results (serotype 13/20, 17F/33C, and 11A/D/1818F). Of the pneumococcal serotypes detected in this study, 69/91 (76%) were not included in the current PCV13. The most frequently identified serotypes were 11A, 13, 15B/15C, 16F and 10A.

Conclusion

The rmPCR assay performed well for the 21 serotypes/-groups included in the assay. However, in our study setting, a large proportion of serotypes were not detected by rmPCR. The sequetyping assay performed well, but did misassign specific serotypes. It may be useful for regions where vaccine serotypes are less common, however confirmatory testing is advisable.     

Determination of Pneumococcal Serotypes in Meningitis Cases in Niger, 2003–2011

Background

The epidemiology of pneumococcal meningitis in the African ‘meningitis belt’ is poorly studied. In order to ensure an effective vaccination strategy and post-vaccination surveillance, we examined the serotype distribution patterns of pneumococcal meningitis in Niger over the period 2003–2011.

Methods

Cerebrospinal fluid (CSF) samples were collected from different health facilities throughout Niger in the frame of the national microbiological surveillance of meningitis. Determination of the serotype of CSF positive for pneumococci was performed using a sequential multiplex PCR method (SM-PCR) adapted with a national algorithm in which 32 different serotypes were covered and grouped into eight consecutive PCR.

Results

The SM-PCR assay could predict the Sp serotype for 779 CSF (88.7%), 98 CSF (11.3%) were not-typeable in our national-adapted algorithm. In total, 26 different serotypes were identified. Serotype 1 (n = 393) was the most prevalent and accounted for 45.3% of infections, followed by serogroups/serotypes 12F/(12A)/(44)/(46) (7.3%), 6/(6A/6B/6C/6D) (5.4%), 14 (5.2%), 5 (4.6%), 23F (4.2%), 45 (3.6%), 2 (3.1%), 18/(18A/18B/18C/18F) (2.9%) and 17 others serotypes with a prevalence of less than 2%. The proportion of serotype 1 in infants(<2 years old) represented only 4.3% of the cases affected by this serotype. In contrast, serotypes 5, 6, 14, 19A and 23F were only detected in very young children.

Conclusions

The proportion of serotype 1 in the pneumococcal meningitis cases and the theoretical vaccine coverage across all age groups advocates for the introduction of a conjugate vaccine (PCV10 or 13) into the Expanded Programme on Immunization (EPI) in Niger. Post-vaccine introduction surveillance supported by molecular approaches will be essential to provide a comprehensive picture of the impact of the vaccine on the burden reduction of pneumococcal meningitis and on pneumococcal serotype distribution.     

Intranasal immunization of the combined lipooligosaccharide conjugates protects mice from the challenges with three serotypes of Moraxella catarrhalis

Background

There are no licensed vaccines available against Moraxella catarrhalis, a significant human respiratory pathogen. Lipooligosaccharide (LOS) based conjugate vaccines derived from individual serotype M. catarrhalis only showed partial protection coverage. A vaccine combining LOS conjugates of two or three serotypes might provide a broader protection.

Methods

Mice were immunized intranasally with the combined conjugates consisting of LOS from serotype A and B or serotype A, B, and C followed by challenge with different M. catarrhalis strains of three serotypes. Mouse lungs, nasal washes, and sera were collected after each challenge for bacterial counts, histological evaluation, cytokine profiles, antibody level and binding activity determinations.

Results

Intranasal administration of the combined LOS conjugates not only enhanced pulmonary bacterial clearance of all three serotypes of M. catarrhalis strains in vaccinated mice, but also elevated serotype-specific anti-LOS immunoglobulin (Ig)A and IgG titers in nasal wash and serum respectively. Mice vaccinated with the combined LOS conjugates also showed increased interferon (IFN)-γ, interleukin (IL)-12, and IL-4 in the lungs after challenges. Compared to the control group, mice immunized with the combined LOS conjugates also showed reduced lung inflammation after M. catarrhalis infections. The hyperimmune sera induced by the combined conjugates exhibited a broad cross-reactivity toward all three serotypes of M. catarrhalis under transmission electron microscopy.

Conclusions

The combined vaccine of serotype A and B LOS conjugates provides protection against most M. catarrhalis strains by eliciting humoral and cellular immune responses.     

Isolation and characterisation of the phospholipase B gene of Cryptococcus neoformans var. gattii

Cryptococcus neoformans var. gattii (serotypes B and C) is a human pathogen, ecologically, biochemically, clinically and genetically different from C. neoformans var. grubii (serotype A) and C. neoformans var. neoformans (serotype D). The phospholipase B (PLB1) gene from serotypes B and C was isolated and characterised. It resembled the serotype A and D genes, with an overall sequence homology of more than 85%. The respective open reading frames were 2236 bp (serotype B) and 2239 bp (serotype C) in length. Each contained six introns and encoded a 68-kDa protein destined for secretion. PLB1 was located on the second smallest chromosome in both serotypes. Gene expression, measured as mRNA, was not regulated by temperature, pH or exogenous nutrients.     

Stability of isoenzyme and kinetoplast DNA (k-DNA) patterns in successively cloned Trypanosoma cruzi populations.

Four Trypanosoma cruzi strains from zymodemes A, B, C and D were successively cloned on BHI-LIT-agar-blood (BLAB). Twenty clones from the first generation (F1), 10 from the second (F2) and 4 from the third (F3) from the strains A138, B147 and C231 were isolated. The D150 strain provided 29 F1 and 23 F2 clones. The strains and clones had their isoenzyme and k-DNA patterns determined. The clones from A138, B147 and C231 strains presented isoenzyme and k-DNA patterns identical between themselves and their respective parental strains. Therefore showing the homogeneity and stability of isoenzyme and k-DNA patterns after successive cloning. The D150 strain from zymodeme D (ZD) showed heterogeneity. Twenty-eight out of 29 clones of the first generation were of zymodeme A and only one was of zymodeme C, confirming previous reports that ZD strains consisted of ZA and ZC parasite populations. The only D150 strain clone of zymodeme C showed a k-DNA pattern identical to its parental strain. The remaining clones although similar among themselves were different from the parental strain. Thus the T. cruzi strains had either homonogeneus or heterogeneous populations. The clones produced by successive cloning provided genetically homogeneous populations. Their experimental use will make future results more reliable and reproducible.     

Delayed hypersensitivity in mice infected with reovirus. I. Identification of host and viral gene products responsible for the immune response

Delayed-type hypersensitivity (DTH) can be demonstrated in mice infected with reovirus by challenging primed animals in the footpad with virus. Maximal responses occur 7 days after immunization with as little as 10(5) viral particles. DTH to reovirus is transferable by lymph node cells and is mediated by T cells as the transfer of reactivity can be abrogated by treatment of cells with anti-Thy 1.2 plus complement. DTH to reovirus is serotype specific, animals infected with reovirus type 1 or 3 only develop DTH responses when challenged with the same serotype with which they were infected. Using recombinant viral clones containing genes from both parental serotypes, we have demonstrated that the S1 gene, the gene encoding the viral hemagglutinin, determines serotype specificity. Furthermore, in adoptive transfer experiments between mice of varying histocompatibility backgrounds, it was found that D or K, IA-IB region identity was required for the transfer of reactivity. These studies demonstrate that specific host and viral genes determine the in vivo cellular immune response to reovirus and should allow a more precise definition of the host cellular immune response to viral antigens.     

Comparative sequence analysis of the hexon gene in the entire spectrum of human adenovirus serotypes: phylogenetic, taxonomic, and clinical implications

The adenovirus (AdV) hexon constitutes the major virus capsid protein. The epitopes located on the hexon protein are targets of neutralizing antibodies in vivo, serve in the recognition by cytotoxic T cells, and provide the basis for the classification of adenoviruses into the 51 serotypes known to date. We have sequenced the entire hexon gene from human serotypes with incomplete or no sequence information available (n = 34) and performed a comparative analysis of all sequences. The overall sequence divergence between the 51 human serotypes ranged from 0.7 to 25.4% at the protein level. The sequence information has been exploited to assess the phylogeny of the adenovirus family, and protein distances between the six AdV species (A to F) and among individual serotypes within each species were calculated. The analysis revealed that the differences among serotypes within individual species range from 0.3 to 5.4% in the conserved regions (765 amino acids [aa]) and from 1.5 to 59.6% in the variable regions (154 to 221 aa). Serotypes of different species showed an expectedly greater divergence both in the conserved (5.9 to 12.3%) and variable (49.0 to 74.7%) regions. Construction of a phylogenetic tree revealed three major clades comprising the species B+D+E, A+F, and C, respectively. For serotypes 50 and 51, the original assignment to species B and D, respectively, is not in accordance with the hexon DNA and protein sequence data, which placed serotype 50 within species D and serotype 51 within species B. Moreover, the hexon gene of serotype 16, a member of species B, was identified as the product of recombination between sequences of species B and E. In addition to providing a basis for improved molecular diagnostics and classification, the elucidation of the complete hexon gene sequence in all AdV serotypes yields information on putative epitopes for virus recognition, which may have important implications for future treatment strategies permitting efficient targeting of any AdV serotype.     

Serotypes and mating types of clinical strains ofCryptococcus neoformans isolated in Taiwan

Twenty-one strains ofCryptococcus neoformans isolated from patients in Taiwan were characterized for serotypes and mating types. Slide agglutination test was performed with 8 factor-specific sera (Iatron Company, Japan) to determine the serotypes. Wheat bran agar (WBA) and malt extract agar (MEA, Wickerham) media were used for the mating tests. Twenty of the isolates were of serotype A, and one was serotype B. Except for 2 strains of serotype A, all of the serotype A strains mated withFilobasidiella neoformans var.neoformans, mating type a. The only serotype B strain mated withF. neoformans var.bacillispora mating type a in MEA medium. These data revealed the low prevalence (1/21; 4.8%) ofC. neoformans var.gattii in Taiwan, a subtropically located island.     

Humoral response to selected antigens of Yersinia enterocolitica and Yersinia pseudotuberculosis in the course of yersiniosis in humans. IV. Specificity of antigens

The specificity of the lipopolisacharydes and released proteins (Yop) of Yersinia was tested using the sera of rabbits immunised with pathogenic and non-pathogenic strain of Y. enterocolitica and Y. pseudotuberculosis as well as selected sera of patients. The results of this study showed a cross-reactions between the different serotypes of Y. enterocolitica with the strongest reactions between the pathogenic serotypes O:3 and O:9 and pathogenic serotype O:5,27 and non-pathogenic serotype O:5. Sera positive for B. burgdorferi and from patients with Graves' disease showed a slight cross-reactivity with Yop proteins of Yersinia. However, the higher cross-reactivity was observed between the LPS of Yersinia and Salmonella spp. Due to the evidence of cross-reactivity the results of serological investigations should be interpreted with caution.     

Diversity of laccase among Cryptococcus neoformans serotypes

The pathogenic yeast C. neoformans is classified into three varieties with five serotypes; var. grubii (serotype A), var. neoformans (serotype D), var. gattii (serotypes B and C), and serotype AD. Melanin is a virulence factor in the species, and its biosynthesis is catalyzed by laccase, encoded by the LAC1 gene. In order to estimate the natural variability of the LAC1 gene among Cryptococcus serotypes, the laccase protein sequence from 55 strains was determined and the phylogenetic relationships between cryptococcal and related fungal laccases revealed. The deduced laccase proteins consisted of 624 amino acid residues in serotypes A, D and AD, and 613 to 615 residues in serotypes B and C. Intra-serotype amino acid variation was marginal within serotypes A and D, and none was found within serotypes AD and C. Maximum amino acid replacement occurred in two serotype B strains. The similarity in the deduced sequence ranged from 80 to 96% between serotypes. The sequence in the copper-binding regions was strongly conserved in the five serotypes. The laccases of the five serotypes were grouped together in the same clade of the phylogenetic tree reconstructed from different fungal laccases, suggesting a monophyletic clade.     

Nuclear differentiation for mating types in the ciliate Dileptus anser: a hypothesis

We have obtained the first data on inheritance and genetic determination of mating types (MTs) in the lower ciliate Dileptus anser (=D. margaritifer). Observation of MT instability in young, just matured exconjugant clones obtained from some (not all) crosses appears to be the key finding in our study. In a clone of this kind, the states of maturity and immaturity (or adolescence) often alternate and/or one MT changes to another, sometimes repeatedly, during the period of several weeks after the clone's maturation. On occasion, all three MTs found in this species can be expressed consecutively. All cells of the culture are synchronously involved in such changes of their sexual state--no spontaneous selfing (intraclonal conjugation) was ever observed in such cultures. These observations suggest that the mat locus in dilepti is a compound integral one; it is inherited as a whole and can specify expression of any one of possible MTs (much as it occurs in Tetrahymena thermophila). Some other mechanisms, supposedly epigenetic ones among them, control what MT will be expressed in a given exconjugant clone in particular. Steady functioning of these mechanisms provides stable, unambiguous differentiation of the compound mat locus to one and only one MT and subsequent Mendelian behavior of the character over sexual generations. If, for some still unknown reasons the control of such differentiation is disturbed, MT expressed in a given exconjugant clone becomes unstable and its Mendelian behavior can be violated.     

Alpha-fetoprotein synthesis during liver regeneration in adult mice of different strains]

Alpha-fetoprotein (AFP) concentration was estimated by radial immunodiffusion in agar technique in the sera of adult mice of 12 inbred strains and F1 hybrids (SWR X B10D2 and B10D2 X SWR) during liver regeneration after CCl4 poisoning. Statistically significant difference in the AFP concentration was found in the male and female sera in 6 of 10 mouse strains studied. The following inter-strain differences were also revealed: the AFP mean levels in the sera of C57BL/6 and B10D2 strains were found to be significantly lower than the corresponding levels in the sera of the majority of the strains tested. F1 hybrids showed to occupy an intermediate position by the AFP content between the parental strains. Small, but statistically significant, differences were revealed between the groups of male F1 hybrids from the direct reciprocal crossings. It is suggested that the control of induction of the AFP synthesis during the liver regeneration in adult mice was realized on the polygene basis.     

Characterization of monoclonal antibodies that recognize common epitopes located on O antigen of lipopolysaccharide of serotypes 1, 9 and 11 of Actinobacillus pleuropneumoniae

Abstract Seven murine monoclonal antibodies (mAbs) against serotype 1 of Actinobacillus (Haemophilus) pleuropneumoniae (reference strain Shope 4074) were produced and characterized. All hybridomas secreting mAbs were reactive with whole-cell antigens from reference strains of serotypes 1, 9 and 11, except for mAb 5D6 that failed to recognize serotype 9. They did not react with other taxonomically related Gram-negative organisms tested. The predominant isotype was immunoglobulin (Ig) M, although IgG_2a, IgG_2b, and IgG₃ were also obtained. The epitopes identified by these mAbs were resistant to proteinase K treatment and boiling in the presence of sodium dodecyl sulfate and reducing conditions; however, they were sensitive to sodium periodate treatment. Enhanced chemiluminescence-immunodetection assay showed that mAbs could be divided in two groups according to the patterns of immunoreaction observed. Group I (mAbs 3E10, 4B7, 9H5 and 11C3) recognized a ladder-like banding profile consistent with the O antigen of lipopolysaccharide (LPS) from smooth strains. Group II (mAbs 3B10 and 9H1) recognized a long smear of high molecular weight which ranged from 60 to 200 kDa. The mAbs were tested against 96 field isolates belonging to serotypes 1, 5, 9, 11 and 12, which had previously been classified by a combination of serological techniques based on polyclonal rabbit sera (counterimmunoelectrophoresis, immunodiffusion and coagglutination). The panel of mAbs identified all isolates of serotypes 9 and 11, but only 66% of those belonging to serotype 1. This may suggest the existence of antigenic heterogeneity among isolates of A. pleuropneumoniae serotype 1. These mAbs reacted with epitopes common to serotypes 1, 9 and 11 of Actinobacillus pleuropneumoniae which were located on the O antigen of LPS.     

Genome sequence of the Bacteroides fragilis phage ATCC 51477-B1

Background

Co-circulation of multiple dengue virus serotypes has been reported from many parts of the world including India, however concurrent infection with more than one serotype of dengue viruses in the same individual is rarely documented. An outbreak of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) occurred in and around Delhi in 2006. This is the first report from India with high percentage of concurrent infections with different dengue virus serotypes circulating during one outbreak.

Results

Acute phase sera from patients were tested for the presence of dengue virus RNA by RT-PCR assay. Of the 69 samples tested for dengue virus RNA, 48 (69.5%) were found to be positive. All the four dengue virus serotypes were found to be co-circulating in this outbreak with DENV-3 being the predominant serotype. In addition in 9 of 48 (19%) dengue virus positive samples, concurrent infection with more than one dengue virus serotype were identified.

Conclusion

This is the first report in which concurrent infections with different dengue virus serotypes is being reported during an outbreak from India. Delhi is now truly hyperendemic for dengue.     

Population Snapshot of Streptococcus pneumoniae Causing Invasive Disease in South Africa Prior to Introduction of Pneumococcal Conjugate Vaccines

We determined the sequence types of isolates that caused invasive pneumococcal disease (IPD) prior to routine use of pneumococcal conjugate vaccines (PCV) in South Africa. PCV-13 serotypes and 6C isolates collected in 2007 (1 461/2 437, 60%) from patients of all ages as part of on-going, national, laboratory-based surveillance for IPD, were selected for genetic characterization. In addition, all 134 non-PCV isolates from children <2 years were selected for characterization. Sequence type diversity by serotype and age category (children <5 years vs. individuals ≥5 years) was assessed for PCV serotypes using Simpson’s index of diversity. Similar genotypes circulated among isolates from children and adults and the majority of serotypes were heterogeneous. While globally disseminated clones were common among some serotypes (e.g., serotype 1 [clonal complex (CC) 217, 98% of all serotype 1] and 14 [CC230, 43%)]), some were represented mainly by clonal complexes rarely reported elsewhere (e.g., serotype 3 [CC458, 60%] and 19A [CC2062, 83%]). In children <2 years, serotype 15B and 8 were the most common serotypes among non-PCV isolates (16% [22/134] and 15% [20/134] isolates, respectively). Sequence type 7052 and 53 were most common among serotypes 15B and 8 isolates and accounted for 58% (7/12) and 64% (9/14) of the isolates, respectively. Serotype 19F, 14, 19A and 15B had the highest proportions of penicillin non-susceptible isolates. Genotypes rarely reported in other parts of the world but common among some of our serotypes highlight the importance of our data as these genotypes may emerge post PCV introduction.