13-valent Conjugate Vaccine Research Articles

Serotype and Genotype Replacement among Macrolide-Resistant Invasive Pneumococci in Adults: Mechanisms of Resistance and Association with Different Transposons

The aim of this study was to analyze trends in adult invasive pneumococcal disease (IPD) due to macrolide-resistant strains and to study the evolution of serotypes, genotypes, and macrolide-resistant determinants of strains collected in a prospective study between 1999 and 2007 in Barcelona, Spain. IPD due to macrolide-resistant strains of serotypes included in the 7-valent conjugate vaccine (PCV7) decreased from 2.16/100,000 (pre-PCV7 period, 1999 to 2001) to 0.80/100,000 (late-PCV7 period, 2005 to 2007) (P = 0.001), whereas IPD due to macrolide-resistant strains of non-PCV7 serotypes increased from 1.08/100,000 to 2.83/100,000 (P < 0.001). These changes were related to a fall of clones of PCV7 serotypes (ST81 [P < 0.05], ST90, ST315, and ST17) and an increase in new clones of serotypes 19A and 24F (ST230) and 33F (ST717) in the late-PCV7 period. The most common phenotype was MLS(B) (90.9%), related to the erm(B) gene. The frequent association between MLS(B) phenotype and tetracycline resistance [tet(M) gene], was related to transposons of the Tn916-family such as Tn6002 or Tn3872. In conclusion, overall adult IPD rates due to macrolide-resistant pneumococci stabilized between 1999 and 2007 in Barcelona. The decrease in macrolide-resistant PCV7 pneumococci was balanced by the increase in macrolide-resistant non-PCV7 pneumococci.

Optimization and Application of a Multiplex Bead-Based Assay To Quantify Serotype-Specific IgG againstStreptococcus pneumoniaePolysaccharides: Response to the Booster Vaccine after Immunization with the Pneumococcal 7-Valent Conjugate Vaccine

We describe the optimization and application of a multiplex bead-based assay (Luminex) to quantify antibodies against polysaccharides of 13 pneumococcal serotypes. In the optimized multiplex immunoassay (MIA), intravenous immune globulin was introduced as an in-house reference serum, and nonspecific reacting antibodies were adsorbed with the commercial product pneumococcal C polysaccharides Multi. The antibody concentrations were assessed in 188 serum samples obtained pre- and post-booster vaccination at 11 months after administration of a primary series of the pneumococcal seven-valent conjugate vaccine (PCV-7) at 2, 3, and 4 months of age. The results of the MIA were compared with those of the ELISA for the serotypes included in the seven-valent conjugated polysaccharide vaccine and for a non-vaccine serotype, serotype 6A. The geometric mean concentrations of the antibodies determined by MIA were slightly higher than those determined by ELISA. The correlations between the assays were good, with R(2) values ranging from 0.84 to 0.91 for all serotypes except serotype 19F, for which R(2) was 0.70. The concentrations of antibody against serotype 6A increased after the administration of PCV-7 due to cross-reactivity with serotype 6B. The differences between the results obtained by ELISA and MIA suggest that the internationally established protective threshold of 0.35 microg/ml should be reevaluated for use in the MIA and may need to be amended separately for each serotype.

Increasing Importance of Multidrug-Resistant Serotype 6A Streptococcus pneumoniae Clones in Acute Otitis Media in Southern Israel

The major aim of this study was to establish the molecular epidemiology dynamics of Streptococcus pneumoniae serotype 6A in acute otitis media, before the introduction of the 7-valent pneumococcal conjugate vaccine. Acute otitis media in Jewish and Bedouin children <5 years old undergoing tympanocentesis during 1999 to 2006, were studied. Serotype 6A was identified by the Quellung reaction and by polymerase chain reaction (PCR) of the wciN gene, to differentiate between 6A and 6C. Antibiogram and molecular typing by pulsed field gel electrophoresis were performed on all 6A isolates. Multilocus sequence typing was performed on representative isolates of each clone. The 7-valent conjugate vaccine had not yet been licensed in Israel during the study period. Serotype 6A constituted 5.8% (254/4408) of all pneumococcal acute otitis media episodes. The yearly proportion of serotype 6A among the Jewish children showed no distinct trend, whereas among the Bedouin children serotype 6A exhibited a significant increase, from 3.0% in 1999 to 7.6% in 2006. Among the Jewish children a single penicillin-nonsusceptible and erythromycin-resistant clone, ST-473, constituted 73.6% of the strains and dominated throughout the study period. Among the Bedouin children, the proportions of the most common, penicillin-nonsusceptible clone, ST-1988, gradually decreased, from 44.1% in 1999 to 2000 to 21.4% in 2005 to 2006, concurrently with the expansion of a multidrug-resistant clone, ST-457, from 5.9% in 1999 to 2000 to 28.6% in 2005 to 2006. The expansion of multidrug-resistant serotype 6A clone occurred before the introduction of the vaccine. Continued surveillance following vaccine introduction is warranted to further investigate its efficacy on vaccine-related serotypes.

Immune response to the 23-valent polysaccharide pneumococcal vaccine after the 7-valent conjugate vaccine in allogeneic stem cell transplant recipients: Results from the EBMT IDWP01 trial

The current recommendations for active immunization after stem cell transplant (SCT) include 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7) from 3 months after transplant, followed by a 23-valent polysaccharide pneumococcal vaccine (PPV23). However, until now, the immune response to PPV23 after PCV7 has not been assessed after SCT. In the EBMT IDWP01 trial, 101 patients received 1 dose of PPV23 at 12 or 18 months, both after 3 doses of PCV7. The efficacy of PPV23 was assessed 1 month later and at 24 months after transplant by the pneumococcal serotype 1 and 5 antibody levels. Serotype 1 and 5 are not included in PCV7. Although the geometric mean concentrations were significantly higher 1 month after PPV23, for both antigens, the response rates (≥0.15 μg/mL), in the range of 68–94%, were not different between groups independent of the assessment date. One PPV23 dose after 3 PCV7 doses, already known to increase the response to PCV7, also extends the serotype coverage given 12 or 18 months after transplant.

Huge impact of assumptions on indirect effects on the cost-effectiveness of routine infant vaccination with 7-valent conjugate vaccine (Prevnar ®)

Several recently published European cost-effectiveness studies on the 7-valent pneumococcal conjugate vaccine (PCV-7: Prevnar ®) have included net-indirect vaccine benefits for non-vaccine protected groups into their studies, which might be too optimistic an approach given recent data. Net-indirect effects result from herd protection minus serotype replacement effects. In this study we analyze the impact of net-indirect effects in non-vaccine protected groups of 5 years of age and older with updated assumptions regarding epidemiologic data and health care unit costs. Without net-indirect benefits for non-vaccine protected groups included the cost-effectiveness ratio is estimated at €72,360 per QALY. In order to obtain cost-effectiveness ratios below the threshold of €50,000 per QALY – which is in the middle of the range that is often referred to in the Netherlands – the net-indirect protective effect should at least be 16% of which has been observed in the USA after the introduction of PCV-7.

CDC Issues Recommendations for a New Pneumococcal Conjugate Vaccine

Target Population: Infectious diseases specialists, as well as physicians, nurses, and public health workers who care for children Sponsoring Organization: CDC Type: Recommendations of the Advisory Committee on Immunization Practices. This report is consistent with recommendations by the American Academy of Pediatrics Committee on Infectious Diseases. Key Points: In February 2000, a 7-valent pneumococcal polysaccharide-protein conjugate vaccine (Prevnar [PCV7]) was licensed for infants and young children in the U.S. Subsequently, the rates of pneumococcal sepsis and meningitis in children fell, but infections caused by nonvaccine serotypes have persisted, and the prevalence of nonvaccine serotypes may be increasing. On February 24, 2010, a 13-valent pneumococcal polysaccharide-protein conjugate vaccine …

Sustained Reductions in Invasive Pneumococcal Disease in the Era of Conjugate Vaccine

Changes in invasive pneumococcal disease (IPD) incidence were evaluated after 7 years of 7-valent pneumococcal conjugate vaccine (PCV7) use in US children. Laboratory-confirmed IPD cases were identified during 1998-2007 by 8 active population-based surveillance sites. We compared overall, age group-specific, syndrome-specific, and serotype group-specific IPD incidence in 2007 with that in 1998-1999 (before PCV7) and assessed potential serotype coverage of new conjugate vaccine formulations. Overall and PCV7-type IPD incidence declined by 45% (from 24.4 to 13.5 cases per 100,000 population) and 94% (from 15.5 to 1.0 cases per 100,000 population), respectively (P< .01 all age groups). The incidence of IPD caused by serotype 19A and other non-PCV7 types increased from 0.8 to 2.7 cases per 100,000 population and from 6.1 to 7.9 cases per 100,000 population, respectively (P< .01 for all age groups). The rates of meningitis and invasive pneumonia caused by non-PCV7 types increased for all age groups (P< .05), whereas the rates of primary bacteremia caused by these serotypes did not change. In 2006-2007, PCV7 types caused 2% of IPD cases, and the 6 additional serotypes included in an investigational 13-valent conjugate vaccine caused 63% of IPD cases among children <5 years-old. Dramatic reductions in IPD after PCV7 introduction in the United States remain evident 7 years later. IPD rates caused by serotype 19A and other non-PCV7 types have increased but remain low relative to decreases in PCV7-type IPD.

Relationship between IgG titers and opsonocytophagocytic activity of anti-pneumococcal antibodies after immunization with the 7-valent conjugate vaccine in allogeneic stem cell transplant

The European Group for Blood and Marrow Transplantation has recently run a prospective, randomized trial comparing an early (3 months) vs a late (9 months) immunization program after allo-SCT with three doses of the conjugate 7-valent pneumococcal vaccine. This trial has shown that the response rate assessed 1 month after the third dose of conjugate vaccine was not inferior after an early vaccination vs a late vaccination. Part of the responder cohort of these patients (n=28) were chosen to assess the functionality of the anti-pneumococcal antibodies through an opsonophagocytic assay, 1 month after the third dose of conjugate vaccine. We have assessed the relationship between IgG titers measured by the pneumococcal ELISA and functional titers measured by opsonophagocytic assay of anti-pneumococcal antibodies. We found a significant correlation between titers for both assays, and conclude that the response to PCV7 after SCT induces functional antibodies.

Prevalência de sorotipos e resistência antimicrobiana de cepas invasivas do pneumococo em crianças: análise de 9 anos

OBJECTIVE: To determine the prevalence of serotypes and antimicrobial susceptibility of strains of pneumococcus in children and to evaluate the implications for vaccine formulation. METHODS: Strains of pneumococcus obtained from children admitted with invasive diseases were isolated at Hospital de Clinicas of Universidade Federal de Uberlândia, Uberlândia, Brazil, and sent to Instituto Adolfo Lutz, Sao Paulo, Brazil, for further identification, serotyping, and determination of antimicrobial susceptibility. RESULTS: From April 1999 to December 2008, 142 strains of pneumococcus, obtained from children under 5 years of age, were analyzed. Seventy-five (52.8%) patients were male, and the age ranged from 1 to 60 months (mean age = 19±15.4 months; median = 15 months). The most common diagnoses were pneumonia [92 cases (64.8%)] and meningitis [33 cases (23.2%)]. The strains were mostly isolated from blood [61 samples (43%)], pleural fluid [52 samples (36.6%)], and cerebrospinal fluid [28 samples (19.7%)]. The most common serotypes were 14, 5, 6B, 1, 6A, 18C, 19A, 3, 9V, 19F, 23F, 9N, and 10A. There were 14 [9.9%] penicillin-resistant strains, which was detected only in the following serotypes: 14, 6B, 19F, 19A, and 23F, being predominant from 2004 to 2008 (p = 0.000). There was reduced susceptibility to co-trimoxazole (79.5%), erythromycin and clindamycin (11.3% each), and ceftriaxone (5.6%). CONCLUSIONS: Penicillin resistance was detected in 9.9% of the strains, being predominant from 2004 to 2008. Twenty different pneumococcal serotypes were identified, and 71.9% of the serotypes were represented in the 7-valent conjugate vaccine (PN CRM7) currently available.

Prevalence of serotypes and antimicrobial resistance of invasive strains of pneumococcus in children: analysis of 9 years

To determine the prevalence of serotypes and antimicrobial susceptibility of strains of pneumococcus in children and to evaluate the implications for vaccine formulation. Strains of pneumococcus obtained from children admitted with invasive diseases were isolated at Hospital de Clínicas of Universidade Federal de Uberlândia, Uberlândia, Brazil, and sent to Instituto Adolfo Lutz, São Paulo, Brazil, for further identification, serotyping, and determination of antimicrobial susceptibility. From April 1999 to December 2008, 142 strains of pneumococcus, obtained from children under 5 years of age, were analyzed. Seventy-five (52.8%) patients were male, and the age ranged from 1 to 60 months (mean age = 19+/-15.4 months; median = 15 months). The most common diagnoses were pneumonia [92 cases (64.8%)] and meningitis [33 cases (23.2%)]. The strains were mostly isolated from blood [61 samples (43%)], pleural fluid [52 samples (36.6%)], and cerebrospinal fluid [28 samples (19.7%)]. The most common serotypes were 14, 5, 6B, 1, 6A, 18C, 19A, 3, 9V, 19F, 23F, 9N, and 10A. There were 14 [9.9%] penicillin-resistant strains, which was detected only in the following serotypes: 14, 6B, 19F, 19A, and 23F, being predominant from 2004 to 2008 (p = 0.000). There was reduced susceptibility to co-trimoxazole (79.5%), erythromycin and clindamycin (11.3% each), and ceftriaxone (5.6%). Penicillin resistance was detected in 9.9% of the strains, being predominant from 2004 to 2008. Twenty different pneumococcal serotypes were identified, and 71.9% of the serotypes were represented in the 7-valent conjugate vaccine (PN CRM7) currently available.

Incidence of invasive pneumococcal disease among children after introduction of a 7-valent pneumococcal conjugate vaccine: a population-based study in Olmsted County, Minnesota.

To examine the effect of the 7-valent pneumococcal conjugate vaccine in a well-characterized population in Olmsted County, Minnesota, with a combination of urban and rural residents likely to have a relatively low risk of invasive pneumococcal disease (IPD). This population-based study analyzed data from children younger than 5 years to determine the incidence of IPD from January 1, 1995, to December 31, 2007. From 1995 through 2007, 29 cases of IPD were identified in the study population, but 2 patients denied research authorization; thus, 27 cases were available for review. From 1995-1999 to 2001-2003, the incidence of IPD decreased from 33.5 (95% confidence interval [CI], 16.6-50.5) to 10.8 (95% CI, 0.0-23.0) cases per 100,000 person-years (68% decrease; P=.046). The incidence subsequently increased to 15.2 (95% CI, 3.0-27.4) cases per 100,000 person-years from 2004 through 2007; however this change was not significant (P=.62). All cases of IPD with available serotype data from 2002 through 2007 (n=5) were due to non-7-valent conjugate vaccine serotypes. Although the baseline incidence of IPD was much lower than that reported in other populations, the overall incidence of IPD decreased significantly in children younger than 5 years after introduction of a 7-valent conjugate vaccine.

Population-Based Surveillance for Invasive Pneumococcal Disease in Homeless Adults in Toronto

BackgroundIdentification of high-risk populations for serious infection due to S. pneumoniae will permit appropriately targeted prevention programs.MethodsWe conducted prospective, population-based surveillance for invasive pneumococcal disease and laboratory confirmed pneumococcal pneumonia in homeless adults in Toronto, a Canadian city with a total population of 2.5 M, from January 1, 2002 to December 31, 2006.ResultsWe identified 69 cases of invasive pneumococcal disease and 27 cases of laboratory confirmed pneumococcal pneumonia in an estimated population of 5050 homeless adults. The incidence of invasive pneumococcal disease in homeless adults was 273 infections per 100,000 persons per year, compared to 9 per 100,000 persons per year in the general adult population. Homeless persons with invasive pneumococcal disease were younger than other adults (median age 46 years vs 67 years, P<.001), and more likely than other adults to be smokers (95% vs. 31%, P<.001), to abuse alcohol (62% vs 15%, P<.001), and to use intravenous drugs (42% vs 4%, P<.001). Relative to age matched controls, they were more likely to have underlying lung disease (12/69, 17% vs 17/272, 6%, P = .006), but not more likely to be HIV infected (17/69, 25% vs 58/282, 21%, P = .73). The proportion of patients with recurrent disease was five fold higher for homeless than other adults (7/58, 12% vs. 24/943, 2.5%, P<.001). In homeless adults, 28 (32%) of pneumococcal isolates were of serotypes included in the 7-valent conjugate vaccine, 42 (48%) of serotypes included in the 13-valent conjugate vaccine, and 72 (83%) of serotypes included in the 23-valent polysaccharide vaccine. Although no outbreaks of disease were identified in shelters, there was evidence of clustering of serotypes suggestive of transmission of pathogenic strains within the homeless population.ConclusionsHomeless persons are at high risk of serious pneumococcal infection. Vaccination, physical structure changes or other program to reduce transmission in shelters, harm reduction programs to reduce rates of smoking, alcohol abuse and infection with bloodborne pathogens, and improved treatment programs for HIV infection may all be effective in reducing the risk.

Cost-effectiveness of a 3-dose pneumococcal conjugate vaccine program in the province of Quebec, Canada

In the province of Quebec, Canada, the pneumococcal 7-valent conjugate vaccine (PCV-7) was licensed in 2001 and a publicly funded program was implemented in 2004, recommending 3 doses for healthy children. An economic analysis was performed both from a health care and societal perspective. Outcomes possibly prevented by PCV-7 and observed in 2006–2007 were compared to expected frequencies based on rates measured before PCV-7 use. Annual program costs were close to $21 M for the health system and $23 M for society. Approximately 20 000 infections were prevented annually and estimated economic benefits were $5 M for the health system and $23 M for society, using a 3% per annum discounting rate. The incremental cost-effectiveness ratio was $18 000 per QALY gained for the health system and the program was close to the break-even threshold in a societal perspective.

Effect of PCV-7 on Nasopharyngeal Carriage

Prevnar, the vaccine to prevent pneumococcal infections in infants and children, is a 7-valent conjugate vaccine (PCV-7). In the U.S. and some other

Regional differences in serotype distribution, pneumococcal vaccine coverage, and antimicrobial resistance of invasive pneumococcal disease among German federal states

Continuous nationwide surveillance of invasive pneumococcal disease has been conducted in Germany for more than 15 years. In this study, 3724 isolates were included. A total of 2065 isolates were obtained from children under 16 years of age from 1997 to 2006, and 1659 isolates were obtained from adults aged 16 years and older between 2002 and 2006. Results were classified to federal states, and supra-regional trends were illustrated by classifying the federal states into the regions ‘North-West’, ‘North-East’ and ‘South’. Among childhood isolates, the most common serotypes were 14 (26.4%), 6B (7.7%), 23F (7.4%), 19F (7.1%), 1 (7.0%), 18C (6.2%), and 7F (5.6%). Serotype coverage for the 7-valent conjugate vaccine was 62.3%. For the 10-valent and 13-valent vaccines (both in development) the coverage was 75.5% and 84.8%, respectively. The 23-valent polysaccharide vaccine had a coverage of 87.3%. The coverage varies considerably among the federal states. Penicillin G resistance was observed in 7.4% of meningitis cases. In the non-meningitis group, no intermediate resistant or resistant strains were detected. Among adults, the most common serotypes were 14 (16.9%), 3 (9.2%), 4 (7.8%), 7F (7.5%), 1 (6.8%), and 9V (6.1%). Serotype coverage for the 7-valent conjugate vaccine was 46.5%. For the pneumococcal conjugate vaccines in development, the coverage was 61.1% (10-valent) and 76.3% (13-valent). The 23-valent polysaccharide vaccine had a coverage of 88.7%. Penicillin G resistance was observed in 6.4% of meningitis cases. Among these, considerably higher rates of resistance were observed in the North-East region (13.0%) than in the North-West (7.1%) and South (1.8%) regions.

Multiplex PCR reveals a high rate of nasopharyngeal pneumococcal 7-valent conjugate vaccine serotypes co-colonizing indigenous Warao children in Venezuela

Knowledge of co-colonization with multiple pneumococcal serotypes is becoming very important in the light of both serotype replacement and switching as a result of vaccination. Co-colonization has been reported to occur in up to 30% of carriers, especially in populations with high Streptococcus pneumoniae carriage rates. For the determination of co-colonization, single colonies of nasopharyngeal specimens are serotyped with the Quellung method, a costly method with a low sensitivity. Here we explore the use of a multiplex PCR to identify simultaneous carriage of the capsular serotypes targeted by the 7-valent conjugate vaccine. We applied this multiplex PCR to 50 primary cultures from the nasopharyngeal swabs of healthy Warao Amerindian children, a population with a high pneumococcal carriage rate, most of them with vaccine serotypes, and we identified a second serotype in 20% (n=10) of the pneumococci carriers. These results were confirmed by detailed serotyping of multiple colonies isolated from the primary culture with the Quellung method. We conclude that the multiplex PCR is a sensitive, simple and cost-effective method for detecting multiple serotypes in nasopharyngeal cultures, and thus might be useful for the monitoring of pneumococcal colonization over time, especially in the surveillance of nasopharyngeal colonization after conjugate vaccination.

Wyeth's pneumococcal 7-valent CRM197 conjugate vaccine [Prevenar] has been added to Saudi Arabia's national immunisation programme

Wyeth's pneumococcal 7-valent CRM197 conjugate vaccine [Prevenar] has been added to Saudi Arabia's national immunisation programme

Emergence of a Multiresistant Serotype 19A Pneumococcal Strain Not Included in the 7-Valent Conjugate Vaccine as an Otopathogen in Children

Emergence of a Multiresistant Serotype 19A Pneumococcal Strain Not Included in the 7-Valent Conjugate Vaccine as an Otopathogen in Children

Differential Effects of Pneumococcal Vaccines against Serotypes 6A and 6C

Because classic pneumococcal serotyping methods cannot distinguish between serotypes 6A and 6C, the effects of pneumococcal vaccines against serotype 6C are unknown. Pneumococcal vaccines contain serotype 6B but not serotypes 6A and 6C. We used a phagocytic killing assay to estimate the immunogenicity of the 7-valent conjugate vaccine (PCV7) in children and the 23-valent polysaccharide vaccine (PPV23) in adults against serotypes 6A and 6C. We evaluated trends in invasive pneumococcal disease (IPD) caused by serotypes 6A and 6C in the United States, using active surveillance. Serum specimens from PCV7-immunized children had median opsonization indices of 150 and < 20 for serotypes 6A and 6C, respectively. Similarly, only 52% of adults (25 of 48) vaccinated with PPV23 showed opsonic indices of > 20 against serotype 6C. During 1999--2006, the incidence of serotype 6A IPD decreased by 91% (from 4.9 to 0.46 cases per 100,000 persons; P < .05) among individuals aged < 5 years and by 58% (from 0.86 to 0.36 cases per 100,000 persons; P < .05) among those aged > or = 5 years. Although the incidence of 6C IPD showed no consistent trend (range, 0-0.6 cases per 100,000 persons) among individuals aged < 5 years, it increased from 0.25 to 0.62 cases per 100,000 persons (P < .05) among those aged > or = 5 years. PCV7 introduction has led to reductions in serotype 6A IPD but not serotype 6C IPD in the United States.

Rapid Consumption of Vancomycin in the Presence of Beta-Lactam Antibiotics Causes Beta-Lactam Antibiotic-Induced Vancomycin-Resistance in Methicillin-resistant Staphylococcus aureus

order to predict the efficacy of the vaccine in the Malaysian population. Methods: A total of 217 strains of S. pneumoniae obtained from invasive (blood, CSF, pleural fluid) and non-invasive sites (respiratory sites) of both pediatric and adult patients were serotyped by the method of Pai et al (2006). Strains were identified by standard methods and their antibiotic resistance profile determined by agar dilution method (PEN, ERY, CRO, CTX, CXM, CIP, GAT, MOX, LVX) and disk diffusion (PEN, ERY, CRO, CXM, AMC, AMP, VAN, SXT, CL, CN10, DA, OX, CIP). Seven different multiplex PCRs were used to determine the following serotypes/serogroups: 1, 2, 3, 4, 5, 8, 13, 14, 20, 21, 31, 34, 37, 38, 39, 40, 44, 46, 6A, 7A, 7B, 7C, 7F, 9A, 9N, 9L, 9L, 10A, 10F, 11A, 11D, 11F, 12A, 12B, 12F, 15A, 15B, 15C, 15F, 16A, 16F, 17F, 33A,35B, 35F, 35A, 35C, and 47F. The cps operon was used as the internal positive control. Results: Of the 217 strains, there were 22.6% PRSP, 27.7% PISP and 49.8% PSSP strains based on their susceptibility to penicillin. Serotypes detected were the 19F, 18C, 15B/C, 23F, 6A/B, 10A, 12A/F, 3, 14, 11A/D, 34, 19A, 16F, 35F/47F, and 7F/A. The most predominant serotype was 19F and it was also predominant in isolates obtained from invasive sites. Serotype 19F and 23F were observed to be common among the PRSP strains, with 35/49 strains serotyped as 19F while 13/49 strains were serotyped as 23F. Only one PRSP strain was serotyped as 34. Serotype 19F was also predominant among the PISP strains. Other serotypes detected among the PISP strains were 6A/B, 11A/D, 23F and 14. However, the distribution of these serotypes were rare. The PSSP strains showed to have other serotypes such as 18C, 15B/C, 6A/B, 10A, 19A, 3, 14, 16F, & 7B/C, 7F and 35F/47F. The distribution of serotype 19F and 23F was rare among this group of isolates. Conclusion: In conclusion, we observe serotype 19F and 23F to be prevalent among the penicillin resistant strains, which has been included in the 7-valent conjugate vaccine. Therefore, the efficacy of this vaccine should be effective in our population. However, it is not possible to predict serotypes that might become predominant in the future.