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A Fenoll

Publications and source records attributed to A Fenoll.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cloning, sequencing, and chromosomal location of a putative class-II aldolase gene from Streptococcus pneumoniae.

The nucleotide sequence of a 1620-bp chromosomal fragment from Streptococcus pneumoniae, containing a putative class-II aldolase gene, has been determined. The N-terminal amino acid (aa) sequence of S. pneumoniae class-II aldolase protein allowed us to determine the initiation site for the putative aldolase gene, and a molecular weight of 31,274 Da was predicted for the protein, after removal of the N-terminal methionine. Northern hybridization and primer extension analysis showed a 1100-nucleotide transcript with a transcription start site located 43 or 42 bp upstream of the start codon. Southern hybridization studies indicated that the putative class-II aldolase gene was in the ApaI fragment 6, SmaI fragment 9, and SacII fragment 12 or 13 of the physical map of S. pneumoniae chromosome. Southern hybridization analysis and partial sequencing performed in another eight streptococcus species, belonging to six different phylogenetic groups, suggested that a class-II aldolase gene with a considerable DNA homology to that of the S. pneumoniae, could exist in these streptococcal species.

Amino Acid Sequence↗
PubMed1999

Epidemiological study of Streptococcus pneumoniae carriers in healthy primary-school children.

To obtain information on the Streptococcus pneumoniae carrier state in Spanish children, 332 healthy 6-year-old children from nine primary schools in northern Spain were screened. Thirty-six percent of the children had positive cultures yielding 128 strains. Seventy-one strains belonged to 14 serogroup/serotypes, the most frequent being 19, 23, 3, 24 and 11. Fifty-seven strains were nontypeable. The identification of strains with equivocal results was confirmed at species level by means of hybridisation with a specific probe, pneumolysin-mediated agglutination and a pathogenicity test in mice. Sixty-four percent of strains showed resistance to penicillin, 22% of these also being resistant to cefotaxime. More than 40% of the strains were resistant to trimethoprim-sulfamethoxazole, tetracycline and erythromycin. Twenty percent of the erythromycin-resistant strains were susceptible to clindamycin. Two strains were resistant to rifampicin and one strain was resistant to ofloxacin. All strains were susceptible to vancomycin. Previous antibiotic administration and having siblings under the age of 2 years correlated with the carriage of pneumococcus. There was no correlation with the carriage of antibiotic-resistant strains, or a record of previous infections, previous hospital admissions or having relatives with chronic respiratory disease.

Animals↗
PubMed1999

The three major Spanish clones of penicillin-resistant Streptococcus pneumoniae are the most common clones recovered in recent cases of meningitis in Spain.

One hundred six isolates of Streptococcus pneumoniae recovered in Spain from patients with meningitis in 1997 and 1998 were characterized by multilocus sequence typing. A heterogeneous collection of genotypes was associated with meningitis in Spain: 65 different sequence types were resolved and, even at a genetic distance of 0.43, there were 37 distinct lineages. Thirty-eight percent of the isolates, including all isolates of serotypes 6B, 9V, 14, and 23F, were resistant to penicillin, and 24% of the isolates were members of the three major Spanish penicillin-resistant or multidrug-resistant clones of serotypes 6B, 9V, and 23F or serotype variants of these clones. These three clones (MICs, 1 to 2 microg of penicillin/ml) were the most common clones associated with pneumococcal meningitis in Spain during 1997 and 1998. Only two of the other clones associated with meningitis were penicillin resistant (MICs, 0.12 to 0.5 microg/ml). One of the two most prevalent penicillin-susceptible clones causing meningitis (serotype 3) has not been detected outside of Spain, whereas the other (serotype 18C) has been recovered from patients with meningitis in the United Kingdom, The Netherlands, and Denmark. The prevalence of meningitis caused by isolates of the three major Spanish penicillin-resistant or multiply antibiotic-resistant clones, which are now globally distributed, is disturbing and clearly establishes their ability to cause life-threatening disease.

Base Sequence↗
PubMed1998

Periodate oxidation of R36A pneumococci greatly enhances production of hybridomas secreting anti-protein antibodies.

Most hybridomas derived from mice immunized with non-capsulated Streptococcus pneumoniae strains secrete antibodies to C-polysaccharide epitopes and very rarely against cell wall proteins. Mild periodate oxidation of the non-capsulated R36A pneumococcal strain destroys C-polysaccharide antigenicity without a noticeable loss in the immunizing capacity for proteins. Following immunization of BALB/c mice with periodate-treated R36A cells, most hybridomas obtained (87.5%) secreted anti-pneumococcal protein antibodies. This strategy can be exploited for the development of MAb to pneumococcal polypeptides which, in turn, will be of use in the analysis of pneumococcal cell wall protein antigens.

Animals↗
PubMed1998

Nucleotide sequence and chromosomal location of L-lactate dehydrogenase gene from Streptococcus pneumoniae.

We report here the 1244-bp sequence of a Streptococcus pneumoniae chromosomal fragment that contains the putative promoter and protein-coding region of the lactate dehydrogenase gene (ldh). The nucleotide sequence predicts a protein of 327 aa with a molecular weight of 35,202 daltons, after removal of the N-terminal methionine residue. The ldh gene is located on the ApaI fragment 1 and SmaI fragment 2 of the previously reported physical map of S. pneumoniae chromosome.

Amino Acid Sequence↗
PubMed1998

Serotype 19A variants of the Spanish serotype 23F multiresistant clone of Streptococcus pneumoniae.

Multiply-antibiotic-resistant isolates of serogroup 19 Streptococcus pneumoniae, possessing altered penicillin-binding protein (PBP) 1A, 2B, and 2X genes that are indistinguishable from those of the Spanish multiresistant serogroup 23F clone, are now commonly encountered in Spain. Those isolates that have been serotyped express type 19F capsular polysaccharide. Serotyping of further isolates, and hybridization using a serotype 19F-specific probe, has shown that some of them are serotype 19A, rather than 19F. The Spanish multiresistant serotype 19A, 19F, and 23F multiresistant strains were all shown to be very closely related in overall genotype, as they were indistinguishable by REP-PCR and by the sequencing of internal fragments of three house-keeping genes. The serotype 19A multiresistant strains, like the serotype 19F multiresistant strains, therefore appear to be a serotype variant of the Spanish multiresistant serotype 23F clone, which presumably has arisen by recombination at the capsular locus.

Bacterial Capsules↗
PubMed1998

Description of two new isolates of Streptococcus pneumoniae in spain that are highly resistant to cefotaxime.

Two strains of Streptococcus pneumoniae isolated from sputum and bronchoalveolar samples with high-level resistance to cefotaxime (MIC = 8 to 16 microg/ml) are described. One of them, belonging to serogroup 19, was also highly resistant to penicillin (MIC = 16 microg/ml), while the other, of serogroup 14, was intermediate in its resistance to penicillin (MIC = 0.25 microg/ml). To our knowledge, these are the first two strains to be isolated in Spain with such high levels of resistance to cefotaxime.

Adult↗
PubMed1997

Molecular bases of three characteristic phenotypes of pneumococcus: optochin-sensitivity, coumarin-sensitivity, and quinolone-resistance.

Streptococcus pneumoniae is uniquely sensitive to amino alcohol antimalarials in the erythro configuration, such as optochin, quinine, and quinidine. The protein responsible for the optochin (quinine)-sensitive (Opts, Qins) phenotype of pneumococcus is the proteolipid c subunit of the FzeroF1 H(+)-ATPase. OptR/QinR isolates arose by point mutations in the atpC gene and produce different amino acid changes in one of the two transmembrane alpha-helices of the c subunit. In addition, comparison of the sequence of the atpCAB genes of S. pneumoniae R6 (Opts) and M222 (an OptR strain produced by interspecies recombination between pneumococcus and S. oralis), and S. oralis (OptR) revealed that, in M222, an interchange of atpC and atpA had occurred. We also demonstrate that optochin, quinine, and related compounds specifically inhibited the membrane-bound ATPase activity. Equivalent differences between Opts/Qins and OptR/QinR strains, both in growth inhibition and in membrane ATPase resistance, were found. Pneumococci also show a characteristic sensitivity to coumarin drugs, and a relatively high level of resistance to most quinolones. We have cloned and sequenced the gyrB gene, and characterized novobiocin resistant mutants. The same amino acid substitution (Ser-127 to Leu) confers novobiocin resistance on four isolates. This residue position is equivalent to Val-120 of Escherichia coli ryGB, a residue that lies inside the ATP-binding domain but is not involved in novobiocin binding in E. coli, as revealed by crystallographic data. In addition, the genes encoding the ParC and ParE subunits of topoisomerase IV, together with the region encoding amino acids 46 to 172 (residue numbers as in E. coli) of the pneumococcal ryGA subunit, were characterized in respect to fluoroquinolone resistance. The gyrA gene maps to a physical location distant from the gyrB and parEC loci on the chromosome. Ciprofloxacin-resistant (CpR) clinical isolates had mutations affecting amino acid residues of the quinolone resistance-determining region of ParC (low-level CpR), or in both resistance-determining regions of ParC and GyrA (high-level CpR). Mutations were found in residue positions equivalent to Ser-83 and Asp-87 of the E. coli GyrA subunit. Transformation experiments demonstrated that topoisomerase IV is the primary target of ciprofloxacin, DNA gyrase being a secondary one.

Amino Acid Sequence↗
PubMed1997

Dot blot assay for the serotyping of pneumococci.

To simplify the serotyping of Streptococcus pneumoniae, a dot bot assay has been developed and compared with the standard quellung reaction in 1,082 isolates. The technique has been demonstrated to be sensitive, specific, easy to perform, and inexpensive. The dot blot assay could be useful when large numbers of pneumococci have to be studied.

Antibodies, Bacterial↗
PubMed1996

Serogroup-specific epidemiology of Streptococcus pneumoniae: associations with age, sex, and geography in 7,000 episodes of invasive disease.

A study sample of 7,010 episodes of invasive Streptococcus pneumoniae disease was obtained by combining 13 existing datasets. Disease episodes due to each of 12 pneumococcal serogroups (1, 3-9, 14, 18, 19, and 23) were then compared with episodes in a constant internal control group to describe serogroup-specific variations in disease frequency by age, sex, and geographic origin. The results are presented as odds ratios (with 95% confidence intervals) derived by logistic regression, with adjustment for the major confounders, including dataset of origin. Variation in the male:female ratios between serogroups is small, suggesting that capsular characteristics are an unlikely explanation for the male preference of S. pneumoniae. Serogroups associated with higher nasopharyngeal prevalence (e.g., 19 and 24) are relatively more common in Europe and North American, while the invasive serotypes 1 and 5 are much more common in South America. The custom of reporting serogroup frequencies in two age groups, children and adults, conceals much of the variation in the age distributions across the whole span of life. The reduction of risk associated with serogroups 6, 14, 18, 19, and 23 beyond childhood follows different gradients, being most abrupt in serogroups 14 and most gradual in serogroup 18. The relative risk of disease with serotype 1 declines steadily throughout life, while with serotypes 3 and 8 it increases over middle age. Serogroups 7 and 23 are found unusually frequently in the third decade of life. Because of the wide differences in the epidemiology of individual serogroups of S. pneumoniae, it is questionable whether pneumococcal infection should continue to be classified as a single disease entity.

Adolescent↗
PubMed1996

Multiply antibiotic-resistant Streptococcus pneumoniae recovered from Spanish hospitals (1988-1994): novel major clones of serotypes 14, 19F and 15F.

We analysed a collection of 95 multiply antibiotic-resistant pneumococci, recovered since 1988 from 14 Spanish hospitals, that have MICs > or = 0.25 microgram benzylpenicillin ml-1. The majority of the isolates were of serogroups 14, 23, 6, 19 and 15, which are currently the serogroups mainly associated with multiresistance in Spain. All of the serogroup 23 isolates were members of the major Spanish serotype 23F multiresistant clone. Similarly, most of the serogroup 6 isolates were members of the major multiresistant serotype 6B clone, or variants of this clone. Eighteen of the 24 isolates of serogroup 19 were members of a highly penicillin-resistant clone that appears to be a serotype 19F variant of the major Spanish serotype 23F multiresistant clone. Eighteen of the 25 isolates of serotype 14 were members of a previously uncharacterized highly penicillin-resistant clone. Thirteen of the 16 isolates of serogroup 15 were members of a single previously unreported clone of serotype 15F that had moderate levels of resistance to penicillin. Approximately 65% of the multiresistant pneumococci that are currently circulating in Spain were members of the three new clones of serotype 14, 15F and 19F that we describe here, or the previously described serotype 6B and 23F clones. The other 35% of isolates were minor variants of the major clones, unrelated minor clones, and unique isolates, many of which appeared to have arisen by horizontal gene transfer events.

Bacterial Proteins↗
PubMed1995

Potential interventions for the prevention of childhood pneumonia: geographic and temporal differences in serotype and serogroup distribution of sterile site pneumococcal isolates from children--implications for vaccine strategies.

Streptococcus pneumoniae is a leading cause of fatal bacterial pneumonia in young children. Pneumococcal polysaccharide vaccines have not been promoted for use in young children because many constituent serotypes are not immunogenic in children < 2 years old. Conjugating pneumococcal polysaccharide epitopes to a protein carrier would likely increase vaccine immunogenicity in children. We reviewed published and unpublished pneumococcal serotype and serogroup data from 16 countries on 6 continents to determine geographic and temporal differences in serotype and serogroup distribution of sterile site pneumococcal isolates among children and to estimate coverage of proposed and potential pneumococcal conjugate vaccine formulas. The most common pneumococcal serotypes or groups from developed countries were, in descending order, 14, 6, 19, 18, 9, 23, 7, 4, 1 and 15. In developing countries the order was 6, 14, 8, 5, 1, 19, 9, 23, 18, 15 and 7. Development of customized heptavalent vaccine formulas, one for use in all developed countries and one for use in all developing countries, would not provide substantially better coverage against invasive pneumococcal disease than two currently proposed heptavalent formulas. An optimal nanovalent vaccine for global use would include serotypes 1, 5, 6B, 7F, 9V, 14, 18C, 19F and 23F. Geographic and temporal variation in pneumococcal serotypes demonstrates the need for a species-wide pneumococcal vaccine.

Age Distribution↗
PubMed1994

Molecular basis of the optochin-sensitive phenotype of pneumococcus: characterization of the genes encoding the F0 complex of the Streptococcus pneumoniae and Streptococcus oralis H(+)-ATPases.

The gene responsible for the optochin-sensitive (OptS) phenotype of Streptococcus pneumoniae has been characterized. Sequence comparisons indicated that the genes involved encoded the subunits of the F0 complex of an H(+)-ATPase. Sequence analysis and transformation experiments showed that the atpC gene is responsible for the optochin-sensitive resistant (OptS/OptR) phenotype. Our results also show that natural as well as laboratory OptR isolates have arisen by point mutations that produce different amino acid changes at positions 48, 49 or 50 of the ATPase c subunit. The nucleotide sequence of the F0 complex of the Streptococcus oralis ATPase has also been determined. In addition, comparison of the sequence of the atpCAB genes of S. pneumoniae R6 (OptS) and M222 (an OptR strain produced by interspecies recombination between pneumococcus and S. oralis), and S. oralis revealed that, in M222, an interchange of atpC and atpA had occurred. We also demonstrate that optochin specifically inhibited the membrane-bound ATPase activity of the S. pneumoniae wild-type (OptS) strains, and found a 100-fold difference between OptS and OptR strains, both in growth inhibition and in membrane ATPase resistance.

Amino Acid Sequence↗
PubMed1992

Comparative in-vitro activity of four peptide antibiotics against penicillin-resistant Streptococcus pneumoniae isolated from cerebrospinal fluid (CSF).

The in-vitro activity of four peptide antibiotics against 43 penicillin-resistant Streptococcus pneumoniae isolated from cerebrospinal fluid (CSF) was evaluated. The activity of SKF104662 was slightly greater to that of vancomycin, teicoplanin and daptomycin (MICs for 90% of the isolates tested 0.06, 0.25, 0.12 and 0.25 mg/L, respectively) and superior to the other 15 drugs tested. The serotype of these penicillin-resistant strains was also determined. The strains that belonged to the predominant serotype 9 were resistant only to penicillin. All six erythromycin- and clindamycin-resistant strains belonged to serotype 6 and three of them were also resistant to chloramphenicol and tetracycline (plus penicillin).

Anti-Bacterial Agents↗
PubMed1990

Identification of atypical strains of Streptococcus pneumoniae by a specific DNA probe.

A specific DNA probe containing a 0.65 Kb fragment coding for the aminoterminal region of the major pneumococcal autolysin (amidase) was constructed, deleting the region involved in the specific recognition of cell wall choline residues. The high specificity of this probe was demonstrated in tests with Streptococcus pneumoniae related species including Streptococcus oralis, which contains choline in its cell wall. The probe was used to characterize pneumococcal isolates showing atypical responses in conventional identification tests. The hybridization obtained with 27 atypical pneumococci and 11 of 17 isolates presumptively identified as viridans streptococci confirmed that the probe is suitable for diagnostic use.

DNA Probes↗