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S Berrón

Publications and source records attributed to S Berrón.

At least 19 recordsLinked to original sources
PubMed2001

Association between asymptomatic carriage and sporadic (endemic) meningococcal disease in an open community.

We analysed a strain collection representative of the overall Neisseria meningitidis population circulating in an open community (46,000 inhabitants, Spain) during an endemic period (30 isolates from patients and 191 from throat cultures of healthy individuals) by both phenotypic and molecular techniques. Almost all patient isolates were assigned to three hyper-virulent lineages (ET-5 complex, ET-37 complex and cluster A4) by both multilocus enzyme electrophoresis (MEE) and pulsed-field gel electrophoresis (PFGE). In contrast, MEE and PFGE assigned 20% and 15% respectively of carrier isolates to the hyper-virulent clones (4% for both methods together). There was also a higher correlation between PFGE and phenotypes associated with virulent clones. These notable differences between the two molecular methods were further observed in more than half the carrier isolates, suggesting that the associations between these strains were distorted by recombination events. However, almost one-third of total endemic strains from symptom-free carriers and almost all patient strains belonged to clones defined by MEE and PFGE, with no known epidemiological connection. These data indicate low transmission and a weak clonal structure for N. meningitidis.

Carrier State↗
PubMed2000

Ex vivo bactericidal activity against group C Neisseria meningitidis in seronegative subjects.

BACKGROUND: To determine the anti-meningococcal C immunological activity by adding functional tests (opsonophagocytosis) to the classical serology techniques. SUBJECTS AND METHODS: 42 adult volunteers were screened using serological methods (determination of total and bactericidal antibodies). Seronegative subjects were tested by opsonophagocytosis. RESULTS: 24 subjects (57%) showed serological evidence of previous contact with Neisseria meningitidis group C antigens: 19 subjects had both total and bactericidal antibodies, two subjects had only total antibodies and three subjects had only bactericidal antibodies. Of the 18 seronegative subjects, five showed ex vivo activity in killing curves with or without polymorphonuclear cells: two subjects exhibited only complement-mediated bactericidal activity, one subject only opsonophagocytosis, and two subjects exhibited both activities. CONCLUSION: The addition of functional tests to the classical serological determination increases the evidence of previous contact with N. meningitidis antigens by 12%.

Adult↗
PubMed2000

Investigation for a more virulent variant among the c:2b:P1.2,5 Spanish meningococcal epidemic strains by molecular epidemiology.

A rise in the incidence of meningococcal disease has occurred in Spain in recent years, especially in some regions in the north-west of the country. Most cases have been caused by meningococci characterised as Neisseria meningitidis C:2b:P1.2,5. A total of 107 C:2b:P1.2,5 meningococcal isolates (60 from patients and 47 from carriers) and 12 isolates showing related antigenic combinations (C:2b:NST, C:2b:P1.2, C:2b:P1.5, C:NT:P1.2,5) was analysed by pulsed-field gel electrophoresis to determine the genetic variability of the epidemic and related strains. Endonucleases BglII and NheI were used to cut chromosomal DNA. When BglII was used, most of the C:2b:P1.2,5 isolates showed the same pulsotype regardless of whether they were from clinical cases or carriers. Isolates showing the principal profile after digestion with endonuclease BglII were analysed with NheI. Four pulsotypes were identified, of which two were found in only one isolate each. The major profiles (1 and 2) showed differential distribution among clinical and carrier isolates; pulsotype 1 was the most frequent among clinical isolates. However, the proportions of isolates showing profiles 1 and 2 were similar among carrier isolates. This could indicate that there are two variants of the C:2b:P1.2,5 strain with differing pathogenicity.

Carrier State↗
PubMed2000

Streptococcus pneumoniae in children in Spain: 1990-1999.

UNLABELLED: This study analyses the serogroups/types (SGTs) and resistance to penicillin and erythromycin of 3921 strains isolated from 1990 to 1999 in children aged 0-14 y in Spanish hospitals of all the autonomous communities. Based on the age of the children, strains have been divided into five groups: 0-6 mo, > 6-1 y, > 1-2 y, > 2-5 y and > 5 y. While only eight SGTs were responsible for 80% of the infections in children from 6 mo to 2 y of age, this number increased to 11 and 16 for the groups > 2-5 y and > 5-14 y, respectively. SGTs 6, 14 and 19 were prevalent in blood and otic exudates. SGTs 1, 4, 5, 12 and 18 were more frequent in invasive disease but serotype 3 was clearly associated with otitis. Serotypes I and 5 were quite significant in children of over 2 y of age, and this should be taken into account in future vaccine formulations. CONCLUSION: Although high, the rate of penicillin resistance in the paediatric population has remained stable in recent years. Conversely, erythromycin resistance is still increasing in our country. Coverage by the 7-valent vaccine was 78 and 81% for blood and otic isolates, respectively. These coverage levels would be increased by 9% and 3% if 9-valent (plus 1 + 5 serotypes) were used and by an additional 2.6% and 7.6% using the 11-valent (plus 3 + 7) formulation.

Adolescent↗
PubMed2000

In vitro susceptibilities of 400 Spanish isolates of Neisseria gonorrhoeae to gemifloxacin and 11 other antimicrobial agents.

The in vitro activity of gemifloxacin versus those of 11 other antimicrobial agents against 400 strains of Neisseria gonorrhoeae was determined by microdilution with supplemented GC agar. A total of 37.5% of the strains were beta-lactamase positive. A total of 70 and 6.4% of the beta-lactamase-negative strains exhibited intermediate and high-level penicillin resistance, respectively. Ceftriaxone and gemifloxacin were the most active drugs (MICs at which 90% of isolates are inhibited, 0.01 versus 0.007 microg/ml, respectively), with 100% of strains inhibited by 0.12 microg/ml.

Anti-Bacterial Agents↗
PubMed1999

Carriage of a new epidemic strain of Neisseria meningitidis and its relationship with the incidence of meningococcal disease in Galicia, Spain.

In Galicia, Spain, a dramatic increase in the incidence of meningococcal disease was seen in the 1995-6. The annual incidence rose to 11 per 10(5) inhabitants, and 80% of identified strains were C:2b:P1.2,5. This led to the implementation of an intensive A+C vaccination campaign for the population aged 18 months to 19 years. During this campaign the prevalence of carriage in areas with high and low incidence was studied. Nasopharyngeal swabs were taken from 9796 subjects immediately before the administration of meningococcal vaccine, plated onto Thayer-Martin plates, incubated and sent for analysis to the Reference Laboratory for Neisseria in Spain. The prevalence of the C:2b: P1.2,5 strains was 0.6% (95% CI 0.29-0.88) in the high incidence area, and 0.41% (95 % CI 0.00-1.04) in the low incidence area, and that of serogroup C (all strains) 1.36% (95% CI 0.80-1.80) and 0.89% (95% CI 0.09-1.69) respectively. The prevalence of N. meningitidis (all strains) was almost the same in both areas (8%). Carriers of the epidemic strain were not found in the 2-4 year age group, that most affected by the disease. Our data showed a wide distribution but a low carriage rate of the epidemic strain C:2b:P1.2,5 in the high and low disease incidence areas studied; the difference in the carriage rates between the two areas was not statistically significant.

Adolescent↗
PubMed1998

Increasing incidence of meningococcal disease in Spain associated with a new variant of serogroup C.

Serogroup B has been the main cause of meningococcal disease in Spain since at least 1979, but in recent years an increase in the prevalence of infection due to serogroup C meningococci has been detected. In 1996, for the first time, most cases of meningococcal disease were caused by serogroup C strains. The sero/subtype of all serogroup C meningococci received from 1993 to June 1996 was determined, and the results showed that C:2b:P1.2,5, the most common phenotype in 1995 and 1996 (63% and 65%, respectively), represented only 4.8% of strains in 1993. The C:2b: P1.2,5 epidemic strains appear to be responsible for the high prevalence of serogroup C in Spain. One hundred fifty-one randomly selected serogroup C strains were analyzed by multilocus enzyme electrophoresis, ribotyping, and pulsed-field gel electrophoresis. Pulsed-field gel electrophoresis provided the most accurate information: more than 80% of the C:2b:P1.2,5 and C:2b:P1.2 isolates exhibited one of two very closely related profiles, while most of the C:2b:NST and C:2b:P1.5 strains had a pattern located at a genetic distance of 0.24 from those two profiles. The results show that C:2b:P1.2,5 strains represent a subclone or a genetic variant of the previously identified Spanish epidemic clone C:2b:non-subtypable strains.

Bacterial Typing Techniques↗
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↗
PubMed1997

[A clone of Neisseria meningitidis serogroup C was responsible in 1994 of an unusual high rate of strains with a moderate resistance to penicillin in Caracas (Venezuela)].

BACKGROUND: The aim of the study was to analyse meningococcal strains isolated from patients in Caracas (Venezuela) with epidemiological markers and to determine their susceptibility to antimicrobial agents. METHODS: We analyzed 29 meningococcal clinical strains isolated during 1994 in Caracas by serogrouping, serotyping and subserotyping, multilocus enzyme analysis (MEE), ribotyping and pulse field electrophoresis (PFGE) profile. We also determined the Minimal Inhibitory Concentration (MIC) to 5 antimicrobial agents. RESULTS: Twenty four (82.7%) were group C meningococcal strains. All group C meningococci were characterized as C: 2b: P1.5, belonging to the same electrophoretic type (ET) by MEE and showing the same profile by PFGE by using Bg/II endonuclease restriction enzyme. These group C meningococci showed two different patterns by ribotyping, with only one band difference. All Group C and one group B N. meningitidis isolates were moderately resistant to penicillin (MIC > or = 0.12 mg/l). CONCLUSIONS: During 1994 an unusual high incidence of meningococcal strains moderately resistant to penicillin (PenMR) was detected in Caracas (Venezuela). A clone of C: 2b: P1.5 meningococci seem to be responsable for this high incidence of PenMR isolates.

Cross Infection↗
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

Interspecies recombination in nature: a meningococcus that has acquired a gonococcal PIB porin.

A vaginal isolate of Neisseria has been reported to resemble Neisseria meningitidis in biochemical characteristics but to react with serological reagents that are specific to the PI porin from Neisseria gonorrhoeae. We have confirmed that this isolate has the biochemical attributes of a meningococcus and have shown that it clusters among meningococcal isolates on a dendrogram based on isoenzyme variation within housekeeping enzymes from populations of N. meningitidis and N. gonorrhoeae. Furthermore, the sequences of the fbp and adk genes were typical of those of N. meningitidis and were distinct from those of N. gonorrhoeae. However, the porB gene was very similar to the por genes of N. gonorrhoeae isolates that express the PIB class of outer-membrane porin (differing from one gonococcal por allele at only a single nucleotide site), and was clearly distinct from the porB genes of N. meningitidis. The isolate therefore appears to be a typical meningococcus, except that its porB gene has been replaced with the por gene from a gonococcus.

Adenylate Kinase↗
PubMed1994

Increase in moderate penicillin resistance and serogroup C in meningococcal strains isolated in Spain. Is there any relationship?

Serogroup B Neisseria meningitidis is the main cause of meningococcal disease in Spain, but in recent years we have detected an increase in the prevalence of infection due to serogroup C meningococci. At the same time, the frequency of moderately penicillin-resistant (PenR) clinical isolates, which include greater numbers of serogroup C meningococci than do penicillin-susceptible (PenS) strains, has also been increasing. When we analyzed the prevalence of serogroups B and C in PenR and PenS meningococcal strains, we found a simultaneous increase in serogroup C strains and a decrease in serogroup B meningococci affecting both PenR and PenS isolates. To analyze this epidemiological change in Spain, we have applied serotyping, subtyping, and multilocus enzyme electrophoresis to serogroup C (PenR and PenS) strains. The two major serotypes were 2b and 2a in both groups (PenR and PenS), but our results suggested an association between serotype 2b and PenR strains. However, multilocus enzyme electrophoresis showed that 75% of the major serotypes belonged to the same electrophoretic type. It does not appear that a new clone distinct from those already established is contributing to the increase in serogroup C meningococci in Spain.

Bacterial Typing Techniques↗
PubMed1992

Epidemiology and molecular basis of penicillin-resistant Neisseria meningitidis in Spain: a 5-year history (1985-1989).

Penicillin-resistant (penr) clinical isolates of Neisseria meningitidis, which do not produce beta-lactamase, were first identified in Spain in 1985; the frequency of their recovery, which has been increasing in the past few years, reached 20% in 1989. Serogrouping, determination of serotypes and subtypes, and multilocus enzyme electrophoresis of the penr strains showed an extensive diversity. Resistance is due, at least in part, to a decreased affinity of penicillin-binding protein (PBP) 2 for penicillin. Similar low-affinity forms of PBP 2 are also found in penr isolates of Neisseria lactamica, Neisseria polysaccharea, and Neisseria gonorrhoeae. Genetic transformation of an N. meningitidis type strain to low-level penicillin resistance with DNA from resistant meningococci and other Neisseria species resulted in transformants that possessed low-affinity forms of PBP 2. These altered forms of PBP 2 have been shown to arise from recombinational events that replace parts of the PBP 2 gene with the corresponding regions from the PBP 2 genes of commensal Neisseria species.

Bacterial Proteins↗