Immunogenicity of a 23-valent pneumococcal polysaccharide vaccine in Brazilian elderly.

Serum antibodies specific for the capsular polysaccharides of Streptococcus pneumoniae provide protection against invasive pneumococcal infection. In Brazil, this vaccine has been used for people over 65 years with clinical risk to develop pneumococcal infection since 1999. We evaluated the immune response of 102 elderly subjects (75.5% females and 24.5% males) with a mean age of 71 years, and 19 young healthy adults (63.2% females and 36.8% males) with a mean age of 27 years. The elderly study group consisted of outpatients who received follow-up care in the Geriatric Department of General Hospital, Faculty of Medicine, University of São Paulo. None had acute illness at the time of vaccination. Both groups were immunized with one intra-deltoid injection with 0.5 ml of a 23-valent pneumococcal polysaccharide vaccine. The total IgG specific antibody concentrations to capsular polysaccharides 1, 3, 5, 6B, 8, and 14 were determined against pre- and 1-month post-vaccination sera. All samples were analyzed according to the second-generation pneumococcal polysaccharide ELISA protocol. We observed that the pneumococcal polysaccharide vaccine evoked consistent antibody increase for serotypes 1, 5, 6B, 8, and 14 (geometric mean concentration increase of 2.46 in the elderly and 2.84 in the young adults). Otherwise, we observed no increase in antibody concentration for serotype 3 in both groups.

Evolution of Streptococcus pneumoniae serotypes and penicillin susceptibility in Latin America, Sireva-Vigía Group, 1993 to 1999. PAHO Sireva-Vigía Study Group. Pan American Health Organization.

BACKGROUND: Since 1993 the Pan American Health Organization has coordinated a surveillance network with the National Reference Laboratories of Argentina, Brazil, Chile, Colombia, Mexico and Uruguay aimed at monitoring capsular types and antimicrobial susceptibility of Streptococcus pneumoniae causing invasive disease in children <6 years of age. METHODS: The surveillance system included children 6 years of age and younger with invasive disease caused by S. pneumoniae. The identification, capsular typing and susceptibility to penicillin of the isolates were conducted using a common protocol, based on standard methodologies. RESULTS: By June, 1999, 4,105 invasive pneumococcal isolates had been collected mainly from pneumonia (44.1%) and meningitis (41.1%) cases. Thirteen capsular types accounting for 86.1% of the isolates (14, 6A/6B, 5, 1, 23F, 19F, 18C, 19A, 9V, 7F, 3, 9N and 4) remained the most common types during the surveillance period. Diminished susceptibility to penicillin was detected in 28.6% of the isolates, 17.3% with intermediate and 11.3% with high level resistance. Resistance varied among countries and increased during this period in Argentina, Colombia and Uruguay. Serotypes 14 and 23F accounted for 66.6% of the resistance. CONCLUSION: These surveillance data clearly demonstrate the potential impact of the introduction of a conjugate vaccine on pneumococcal disease and the need for more judicious use of antibiotics to slow or reverse the development of antimicrobial resistance.

Presence of international multiresistant clones of Streptococcus pneumoniae in Colombia.

In Colombia, penicillin resistance of Streptococcus pneumoniae invasive isolates recovered from children less than 5 years old has increased from 10% in 1994 to 49.4% in 1999, suggesting the circulation of international resistant clones in the country. A total of 167 S. pneumoniae invasive isolates with diminished susceptibility to penicillin (DSP) were studied. The techniques used were pulsed-field gel electrophoresis (PFGE) and restriction fragment length polymorphism (RFLP) of penicillin-binding proteins (PBPs) genes (2B, 2X, and 1A). Forty-nine serotype 23F isolates were grouped in two clusters: 15 (31%) multiresistant isolates showed PFGE pattern A and PBP I profile, thus making them indistinguishable from Spain23F-1 clone, and 34 (69%) with PFGE pattern C, PBP II profile, and intermediate level resistance (ILR) to penicillin and TMP-SMX, features unique to a Colombian clone. Fifty-five serotype 14 isolates were assigned to PFGE B pattern, PBP III profile, having high-level resistance to penicillin, and TMP-SMX, similar to the France9V variant 14. This same pattern was present in five capsular type 9V isolates. Four serotype 14 isolates were assigned to PFGE pattern F, and appeared to be similar to Slovakia(14)-10 PFGE pattern, although they had different PBP profiles. Nine capsular type 6B and one 6A isolates belonged to PFGE pattern M, similar to Spain6B-2, although they showed different PBP profiles. The remaining 44 isolates, corresponding to serotypes 14, 6B, 19F, and 34, showed variable PFGE and PBP patterns. These results show that as many as two international clones may be circulating in Colombia as well as a unique, widely distributed 23F clone with ILR to penicillin. Additionally, some Colombian isolates capsular type 14 and 6B might be related to Slovakia(14)-10 Spain6B-2 clones, respectively.

Distribution of capsular types and penicillin-resistance of strains of Streptococcus pneumoniae causing systemic infections in Argentinian children under 5 years of age. Streptococcus pneumoniae Working Group.

Streptococcus pneumoniae (SPN) is the most common cause of invasive infections in children, with high levels of mortality in developing countries. An increase in frequency of penicillin-resistant strains is reported in most parts of the world. A study was undertaken in Argentina and 5 other countries of the region, to determine the type distribution and penicillin resistance rate of SPN isolated from invasive infections in children less than 5 years old. Between June 1994 and March 1996, a total of 505 SPN isolated from sterile sites were collected from 15 hospitals located in 9 cities of different geographic areas. Clinical and epidemiological data from 443 children were analyzed. Sixty five percent SPN were isolated from children less than 2 years old. Pneumonia was the clinical diagnosis in 58% of the cases, meningitis in 22%, and sepsis in 10.6%. Isolates were recovered from blood (51.2%), pleural fluid (22.7%), CSF (20.7%), and other sterile sites (5.4%). Thirty different pneumococcal capsular types were identified and the 10 most frequent in descending order were: 14, 5, 1, 6A/6B, 7F, 9V, 19F, 19A, 16F y 23F, representing 89.3% of the total. Overall, 13.1% of isolates showed intermediate resistance to penicillin while 11.3% showed high resistance. Lethality was 8.8%, without correlation with penicillin-resistance and/or type. These result should be used in selecting the optimal combination of specific types for a conjugate vaccine, useful in children less than 2 years old and for considering therapeutic strategies for invasive pneumococcal infections.

Molecular epidemiologic characterization of penicillin-resistant Streptococcus pneumoniae invasive pediatric isolates recovered in six Latin-American countries: an overview. PAHO/Rockefeller University Workshop. Pan American Health Organization.

The Pan American Health Organization (PAHO) has conducted a study of Streptococcus pneumoniae in six Latin-American countries: Argentina, Brazil, Chile, Colombia, Mexico, and Uruguay. Sterile site isolates from children aged < or =5 years showing clinical symptoms of pneumonia (as defined by the clinical criteria of WHO), meningitis, sepsis or bacteremia (without infectious foci), arthritis, and peritonitis were the source of most of the invasive pneumococcal isolates collected between the end of 1993 and 1996 in the six participating countries. Partial characterization of these isolates (antibiotic resistance and serotyping) have already been described (Microbial Drug Resistance 3:(2):131-163, 1997). In the next phase of the study, 326 S. pneumoniae isolates with reduced penicillin susceptibility were transferred to the Laboratory of Microbiology at The Rockefeller University for molecular characterization, and a summary and overview of the findings is described in this article. Some of the most interesting findings were as follows: (1) There was a surprisingly high representation of two internationally spread clones, which made up >80% of the strains with penicillin MIC of 1 microg/ml or higher; most of these isolates were recovered in large cities, supporting the likelihood that the source of these clones is through international travel. (2) The frequency of resistance to trimethoprim/sulfamethoxazole was extremely high (present in 85% of all isolates with decreased penicillin susceptibility). (3) None of these isolates was resistant to ofloxacin, and macrolide resistance was rare (present in 6.4% of the isolates). (4) There was an apparent inverse relationship between level of penicillin resistance and genetic diversity. (5) There were striking differences in the "microbiologic profiles" of the six different Latin-American countries.

Geographic distribution of penicillin resistance of Streptococcus pneumoniae in Brazil: genetic relatedness.

From January 1993 through December 1996, 1,252 Streptococcus pneumoniae strains from different geographic regions of Brazil were studied for penicillin (Pen) susceptibility. All pneumococci were isolated from normally sterile fluids from patients, newborns to 88 years old. Pen resistance (R) had a mean rate of 15.1%, with 14.5% of strains showing intermediate level Pen-R and 0.6% showing high-level Pen-R. Similar Pen-R rates were observed in different regions of the country, in the range of 9.5% to 17.1%. A Pen-R increase was noted from 9.6% in 1993 to 20.6% in 1996. Pen-R was mostly associated to serotypes 6B, 14, 19A, and 23F (89%). Chromosomal DNA relatedness of Pen-R strains was determined by pulsed field gel electrophoresis (PFGE). High genetic diversity was identified, being represented by 27 patterns among the 92 strains. Two important features were observed: the predominance of relatively low-level Pen MIC (range 0.1-0.5 mg/L) in 86 of the 92 strains, and the presence of 60.8% as four major PFGE clusters unique to Brazil. Another feature was the geographic spread of these clusters over large distances in the country. The city of São Paulo seems to be a Pen-R focus (18.4%) in Brazil. Only two strains representing the international clone B widely spread in France, Portugal, and Spain, belonging to serotype 14, were found.

Haemophilus influenzae resistance in Latin America: systematic review of surveillance data.

Haemophilus influenzae is a relevant cause of morbidity and mortality among children under 5 years of age in the developing world. In Latin America, H. influenzae type b (Hib) conjugate vaccine and surveillance of H. influenzae antimicrobial susceptibility have been implemented in recent years. We have undertaken a systematic review and a pooled analysis on H. influenzae antimicrobial resistance, including reports of 15 Latin America countries over a 10-year period (1990-2000). We have found that 450 (21.4%) of 2,100 invasive isolates were beta-lactamase producers compared to 145 (14.5%) of 998 isolates of noninvasive isolates (p < 0.05). Ampicillin resistance was detected among 783 (21.9%) of 3,577 invasive isolates compared to 111 (17.2%) of 646 noninvasive strains (p < 0.05). In contrast, 568 (41.9%) of 1,355 noninvasive strains were trimethoprim-sulfamethoxazole (TMP-SMX) resistance against 241 (26.9%) of 897 invasive ones (p < 0.05). Therefore, TMP-SMX resistance was more common in nonsterile fluids than in sterile fluids. Over time, rates of beta-lactamase-producing strains were stable in Brazil and Mexico, whereas rates of TMP-SMX resistance were increasing in Brazil. It is predictable that following the Hib immunization, Latin America countries will be faced with increased nontypeable H. influenzae infection. Although standing by the nontypeable H. influenzae vaccine, in this novel epidemiological scenario of post-Hib vaccination in Latin America settings there is a need to improve H. influenzae resistance monitoring to guide clinicians to choose efficacious antimicrobial therapy.

Antimicrobial susceptibilities and capsular types of invasive Streptococcus pneumoniae isolated in children in Mexico City.

As part of the Sistema Regional de Vacunas (SIREVA) initiative, we conducted a surveillance study to determine the relative prevalence of capsular types of Streptococcus pneumoniae and antimicrobial susceptibility of invasive isolates in children less than 5 years old. We collected 220 isolates and found 33 of the 90 known types, with type 23F as the most common followed by types 6A+B, 14, 19F, and 19A. High penicillin resistance was found in 49 strains (22.2%), 31 belonging to type 23F. Twenty-nine (13.1%) were resistant to erythromycin, 95 (43.1%) were resistant to chloramphenicol, and 24 (10.9%) were resistant to cefotaxime. No strains were resistant to vancomycin.

Predominance of the multiresistant 23F international clone of Streptococcus pneumoniae among isolates from Mexico.

During a surveillance study to determine the relative prevalence of capsular types of Streptococcus pneumoniae and antimicrobial susceptibility of invasive isolates in children <5 years old in Mexico City, 220 isolates were collected. The serotype 23F was the most common found, followed by types 6A + B, 14, 19F, and 19A. Diminished susceptibility to penicillin was detected in 106 isolates (48.2%), and high penicillin resistance was found in 49 strains (22.2%), 31 belonging to type 23F. Resistance was also observed to erythromycin (13.1%), to chloramphenicol (43.1%), and to cefotaxime (10.9%). No strains were resistant to ofloxacin or vancomycin. Forty-four of the highly penicillin resistant isolates (penicillin MIC > or =2.0 microg/ml) were examined with molecular fingerprinting techniques; 29 (65.9%) of these isolates (all except two strains) were serotype 23F and shared subtype variants of PFGE type A characteristic of the internationally spread Spanish/USA clone of S. pneumoniae. These strains were also resistant to trimethoprim/sulfametoxasole (TMP/SMX), chloramphenicol, and tetracycline, and most of them were susceptible to erythromycin. Another 6 of the highly penicillin-resistant strains (serogroups 9 and 14) showed PFGE fingerprints and antimicrobial susceptibility pattern characteristic of a second internationally spread clone (French/Spanish clone) and carried resistance to penicillin and TMP/SMX. The rest of the 9 penicillin-resistant isolates were represented by 7 distinct additional PFGE types. The findings suggest that almost 80% of all highly penicillin resistant strains may have been "imported" into Mexico.

Antibiotic resistance in Streptococcus pneumoniae in six Latin American countries: 1993-1999 surveillance.

The impact of invasive pneumococcal invasive disease is increased by the emergence of antibiotic resistance. We report regional and temporal variations in antibiotic resistance for 4,105 invasive Streptococcus pneumoniae isolates collected from Latin American children <5 years, between 1993 and 1999. Reduced susceptibility to penicillin was detected in 1,182 isolates (28.8%); 36% of these were resistant (> or = 2 microg/ml), including 12.6% with MIC > or = 4 microg/ml, occurring primarily in serotypes 14 and 23F. Reduced susceptibility to third-generation cephalosporins was detected in 12.1% of the collection. Mexico had the highest proportion of reduced susceptibility to penicillin (51.6%) and to third-generation cephalosporins (22%), whereas Brazil had the lowest at 20.9% and 0.7%, respectively. Isolates cultured from patients with pneumonia were more likely to have reduced susceptibility to third-generation cephalosporins than isolates from patients with meningitis (p < 0.0001). Susceptibility to trimethoprim-sulfamethoxazole, chloramphenicol, erythromycin, and vancomycin was tested by disk diffusion for 2.899 isolates. Reduced susceptibility was observed for 45.6%, 11.5%, 6.9%, and 0%, respectively. Thirty-one percent of the strains were resistant to > or = 2 drugs. High levels of antibiotic resistance in Latin America emphasize the need for the development of and adherence to rational antibiotic use guidelines. On-going surveillance will monitor the impact of these programs.

Prevalence of serotypes and antimicrobial resistance of streptococcus pneumoniae strains isolated from Brazilian children with invasive infections. Pneumococcal Study Group in Brazil for the SIREVA Project. Regional System for Vaccines in Latin America.

A laboratory surveillance study was developed in Brazil in 1993 to determine capsular types and antimicrobial susceptibility of Streptococcus pneumoniae strains. By studying 360 strains isolated from children with invasive infections in three different cities, 8 out of 34 types were identified as being the most prevalent and considered as the reference group for further analyses. This group comprised 77.7% of all strains studied, and includes the types 1, 5, 6A/B, 9V, 14, 19F, 19A, and 23F. The prevalence of this reference group was significantly higher among strains isolated from children with pneumonia than meningitis. Similarly, this group was more prevalent among strains isolated from children 3 to 6 years of age than from children under 2 years of age. Most strains (78.6%) were found to be susceptible to penicillin and only 1.4% showed high resistance to this antibiotic. However, intermediate resistance to penicillin was detected in 20% of the strains. This laboratory surveillance will be maintained and extended to other cities of Brazil to better define and monitor the trends of pneumococcal infections for proper control and prevention.

Distribution of capsular types and antimicrobial susceptibility of invasive isolates of Streptococcus pneumoniae in Colombian children. Pneumococcal Study Group in Colombia.

Streptococcus pneumoniae is the leading bacterial cause of childhood pneumonia in the developing world. This study describes the type distribution and antimicrobial susceptibility of invasive pneumococcal isolates from Colombian children and is part of the Sistema Regional de Vacunas (SIREVA), a PAHO regional initiative designed to determine the ideal serotype composition of a protein polysaccharide pneumococcal conjugate vaccine for use in children less than 5 years old in Latin America. In Colombia, during the study period, centres in Bogota, Medellin, and Cali collected 324 S. pneumoniae isolates from invasive diseases, 238 (73.5%) from children under the age of 2. Pneumonia was the clinical diagnosis in 41.3% cases, meningitis in 41%, and sepsis in 11.2%. The seven most frequent types included 14(21.9%), 5(10.5%), 23F(9.6%), 1(9%), 6B(9%), 19F(7.1%), and 6A(6.2%). The frequency of diminished susceptibility to penicillin (DSP) was 12%, with 8.9% of isolates showing intermediate level resistance and 3.1% showing high level resistance. Among DSP isolates, 23% were also resistant to cefotaxime, 33.3% to erythromycin, 48.7% to chloramphenicol, and 74.3% to trimethoprim/sulfamethoxazole. Multiple resistance was detected in 59% of the isolates that have DSP. Penicillin resistance was associated with types 23F (53.8%) and 14 (25.6%). These data provides information on capsular types prevalent in Colombia that will not only allow the formulation of an ideal vaccine for the region but also reinforce the need for ongoing regional surveillance.

Characterization of the common antigenic lipopolysaccharide O-chains produced by Bordetella bronchiseptica and Bordetella parapertussis.

Representative strains of Bordetella bronchiseptica and B. parapertussis were found to produce smooth lipopolysaccharides (LPS) having identical antigenic O-polysaccharide components composed of linear unbranched polymers of 1,4-linked 2,3-diacetamido-2,3-dideoxy-alpha-L-galacto-pyranosyluronic acid residues. These LPSs differed from the LPS of B. pertussis which produces only rough-type LPS, devoid of O-polysaccharide. While B. bronchiseptica and B. parapertussis had chemically and immunologically identical O-polysaccharide structures, their core oligosaccharide components differed. The core oligosaccharide of B. parapertussis was chemically distinct from the core of B. bronchiseptica which appeared to be structurally and immunologically similar to a core oligosaccharide of B. pertussis.

The capsular polysaccharide of Klebsiella serotype K60; a novel, structural pattern.

Non-linear capsular polysaccharides of Klebsiella bacteria usually have a single side-chain per repeating unit, or, less commonly, two side-chains attached to the same unit. The capsular polysaccharide from Klebsiella serotype K60 is unique in having three side-chains in the heptasaccharide repeating-unit shown. The structure, including the configuration of the glycosidic linkages, was established mainly by characterization of the oligosaccharides obtained by partial hydrolysis of both the original, capsular polysaccharide and the polymer resulting from the removal, by Smith degradation, of the side chains (Formula, see text).

Structure of the lipopolysaccharide antigenic O-chain produced by Salmonella ohio (O:6,7).

Salmonella ohio, which belong to Group C1 (0:6,7) of the Kauffmann-White classification system, produces a smooth lipopolysaccharide which by glycose analysis, methylation, deamination, and 1H-n.m.r. studies was shown to have an O-polysaccharide chain composed of a repeating hexasaccharide unit having the structure [----2)-[alpha-D-Glcp-(1----3)]-alpha-D-Manp-(1----2)-alpha-D-M anp- (1----2)-beta-D-Manp-(1----3)-beta-D-GlcpNAc-(1----2)-beta-D-Ma np-(1----]n.

Preparation of a branched heptasaccharide by bacteriophage depolymerization of Klebsiella K60 capsular polysaccharide.

Bacteriophage phi 60 possesses an endoglucosidase that depolymerizes the capsular polysaccharide of Klebsiella K60 into a heptasaccharide having two single beta-D-glucopyranosyl side-chains. This bulky oligosaccharide may be used as a probe to examine the combining sites of immunoglobulins. The 1H- and 13C-n.m.r.-spectral data of the oligosaccharide are reported.

Structure of the major lipopolysaccharide antigenic O-chain produced by Salmonella carrau (O:6, 14, 24).

Salmonella carrau, which belongs to group H (O:6, 14, 24) of the Kauffmann-White classification system, produced a major (90%) smooth lipopolysaccharide which by SDS-PAGE, glycose analysis, methylation, periodate oxidation, deamination, and 1H- and 13C-n.m.r. studies was shown to have an O-polysaccharide moiety composed of a repeating pentasaccharide having the structure: (formula: see text).

Novel oligosaccharides obtained by bacteriophage degradation of the polysaccharide from Klebsiella serotype K26.

Bacteriophage phi 26 was used to depolymerize the polysaccharide of Klebsiella K26, yielding three oligosaccharides. The major product was the heptasaccharide repeating unit, with one of the minor products being the fourteen-sugar oligosaccharide corresponding to two repeating units. The other minor product was unusual since it was a hexasaccharide devoid of the terminal, pyruvate-containing galactose unit present in the side chain of the normal repeating unit. Phage phi 26 was shown to act as a beta-galactosidase, and hence it may have the ability to remove the terminal beta-galactose residue in the side chain.

Characterization of infectious bronchitis viruses isolated from outbreaks of disease in commercial flocks in Brazil.

Fifteen isolations of infectious bronchitis (IB) virus were made from a total of 126 Brazilian poultry flocks of all ages that were examined. These flocks (14 chicken and 1 quail) were experiencing a variety of IB-like conditions including respiratory disease, digestive and kidney problems, and drops in egg production. One of the isolates was of the Massachusetts serotype. The remainder were examined by means of cross-neutralization tests in tracheal organ cultures and were shown to belong to at least four antigenic groups, all different from ones described previously in other countries. Some, but not all, of the flocks from which they were isolated had been vaccinated against IB with vaccines of the Massachusetts serotype. In vivo protection studies showed that the MA5 vaccine (of the Massachusetts serotype) protected well against challenge with four of these isolates, representing the different serotypes reported in this study.

Adoption of three Rs alternatives for regulatory testing of vaccines in the developing world: possibilities and barriers.

Animals have been widely used in the development, production and quality control of vaccines. The availability of newer vaccines consisting of well-defined, purified antigens has facilitated the use of in vitro techniques for establishing vaccine potency. At the same time, increased awareness and social concern has lead to attempts to reduce the use of animals, refining animal-based methodologies to decrease distress and/or replacing animal tests by alternatives. Substitute procedures for "potency testing" of diphtheria and tetanus toxoid-containing vaccines have been developed that require fewer animals and preclude the use of lethal challenge. The Pan American Health Organization has been working together with RIVM to assist countries in the Region of the Americas to implement these procedures in their regulatory quality control activities. There have been important advances in this programme. Although difficulties may arise in the implementation process, due to the perception that these alternatives may be costlier, the use of "Good Practices for the Use of Animals" may show this idea to be incorrect. The final decision for implementation will be taken on the basis of common sense and application of the best science available.