1. Changes in serotype distribution of Haemophilus influenzae meningitis isolates identified through laboratory-based surveillance following routine childhood vaccination against H. influenzae type b in Brazil
Abstract
“Following routine childhood vaccination against Haemophilus influenzae type b (Hib) disease in Brazil in 1999, passive laboratory surveillance reported increasing numbers of non-b serotypes and nontypeable H. influenzae (NTHi) from meningitis cases. To characterize this increase, we analyzed data on 3910 H. influenzae isolated from cerebrospinal fluid or blood from meningitis cases that were sent to the national reference laboratory for serotyping from 1990 to 2008. Hib accounted for 98% of H. influenzae meningitis isolates received during 1990–1999 versus 59% during 2000–2008, while non-b serotypes increased from 1% to 19% and NTHi increased from 2% to 22% of H. influenzae isolates received during the two periods. Higher proportions of non-b serotypes and NTHi than Hib were isolated from blood rather than cerebrospinal fluid. Estimated incidence rates for H. influenzae meningitis for Sao Paulo state remained below 1 case per million population during 2000–2008, although annual incidence of NTHi meningitis (mean, 0.03 cases per 100,000 population) increased in several age groups. Changes in surveillance for H. influenzae following introduction of Hib conjugate vaccine likely contributed to increased numbers of non-b and nontypeable H. influenzae meningitis isolates received at the national reference laboratory”
Links
https://www.ncbi.nlm.nih.gov/pubmed/21945960
Citation
Zanella, Rosemeire C., SÃorgio Bokermann, Ana LÃcia S.s. Andrade, Brendan Flannery, and Maria Cristina De C. Brandileone. "Changes in Serotype Distribution of Haemophilus Influenzae Meningitis Isolates Identified through Laboratory-based Surveillance following Routine Childhood Vaccination against H. Influenzae Type B in Brazil." Vaccine 29.48 (2011): 8937-942.
“Following routine childhood vaccination against Haemophilus influenzae type b (Hib) disease in Brazil in 1999, passive laboratory surveillance reported increasing numbers of non-b serotypes and nontypeable H. influenzae (NTHi) from meningitis cases. To characterize this increase, we analyzed data on 3910 H. influenzae isolated from cerebrospinal fluid or blood from meningitis cases that were sent to the national reference laboratory for serotyping from 1990 to 2008. Hib accounted for 98% of H. influenzae meningitis isolates received during 1990–1999 versus 59% during 2000–2008, while non-b serotypes increased from 1% to 19% and NTHi increased from 2% to 22% of H. influenzae isolates received during the two periods. Higher proportions of non-b serotypes and NTHi than Hib were isolated from blood rather than cerebrospinal fluid. Estimated incidence rates for H. influenzae meningitis for Sao Paulo state remained below 1 case per million population during 2000–2008, although annual incidence of NTHi meningitis (mean, 0.03 cases per 100,000 population) increased in several age groups. Changes in surveillance for H. influenzae following introduction of Hib conjugate vaccine likely contributed to increased numbers of non-b and nontypeable H. influenzae meningitis isolates received at the national reference laboratory”
Links
https://www.ncbi.nlm.nih.gov/pubmed/21945960
Citation
Zanella, Rosemeire C., SÃorgio Bokermann, Ana LÃcia S.s. Andrade, Brendan Flannery, and Maria Cristina De C. Brandileone. "Changes in Serotype Distribution of Haemophilus Influenzae Meningitis Isolates Identified through Laboratory-based Surveillance following Routine Childhood Vaccination against H. Influenzae Type B in Brazil." Vaccine 29.48 (2011): 8937-942.
2. Changing epidemiology of invasive Haemophilus influenzae in Ontario, Canada: Evidence for herd effects and strain replacement due to Hib vaccination
Abstract
“The epidemiology of invasive Haemophilus influenzae infections was evaluated in Ontario between 1989 and 2007 to assess the impact of the introduction of the conjugate H. influenzae serotype b (Hib) vaccine in the early 1990s on Hib and non-Hib serotypes in both vaccinated and unvaccinated cohorts as well as the possibility of “strain replacement” with non-vaccine H. influenzae strains. Data were collected by the provincial Public Health Laboratories-Toronto, Ontario Agency for Health Protection and Promotion, which performed almost all serotyping on invasive (blood, CSF, other sterile sites) H. influenzae strains isolated in the province during the study period. Temporal trends for Hib, other typeable strains, and nontypeable H. influenzae were evaluated by Poisson regression, controlling for the specimen submissions. Prior to infant Hib vaccination, the most commonly observed serotype was serotype b (64.9%). Subsequently, 70.3%, 13.6%, and 9.4% of isolates were non-typeable, serotype f, and serotype b, respectively. Infant Hib vaccination resulted in a decrease in Hib incidence in all age groups (pooled IRR 0.432) and marked increases of non-typeable and serotype f H. influenzae in children aged”
Links
https://www.ncbi.nlm.nih.gov/pubmed/20398617
Citation
Adam, H.j., S.e. Richardson, F.b. Jamieson, P. Rawte, D.e. Low, and D.n. Fisman. "Changing Epidemiology of Invasive Haemophilus Influenzae in Ontario, Canada: Evidence for Herd Effects and Strain Replacement Due to Hib Vaccination." Vaccine 28.24 (2010): 4073-078
“The epidemiology of invasive Haemophilus influenzae infections was evaluated in Ontario between 1989 and 2007 to assess the impact of the introduction of the conjugate H. influenzae serotype b (Hib) vaccine in the early 1990s on Hib and non-Hib serotypes in both vaccinated and unvaccinated cohorts as well as the possibility of “strain replacement” with non-vaccine H. influenzae strains. Data were collected by the provincial Public Health Laboratories-Toronto, Ontario Agency for Health Protection and Promotion, which performed almost all serotyping on invasive (blood, CSF, other sterile sites) H. influenzae strains isolated in the province during the study period. Temporal trends for Hib, other typeable strains, and nontypeable H. influenzae were evaluated by Poisson regression, controlling for the specimen submissions. Prior to infant Hib vaccination, the most commonly observed serotype was serotype b (64.9%). Subsequently, 70.3%, 13.6%, and 9.4% of isolates were non-typeable, serotype f, and serotype b, respectively. Infant Hib vaccination resulted in a decrease in Hib incidence in all age groups (pooled IRR 0.432) and marked increases of non-typeable and serotype f H. influenzae in children aged”
Links
https://www.ncbi.nlm.nih.gov/pubmed/20398617
Citation
Adam, H.j., S.e. Richardson, F.b. Jamieson, P. Rawte, D.e. Low, and D.n. Fisman. "Changing Epidemiology of Invasive Haemophilus Influenzae in Ontario, Canada: Evidence for Herd Effects and Strain Replacement Due to Hib Vaccination." Vaccine 28.24 (2010): 4073-078
3. Emergence of non-serotype b encapsulated Haemophilus influenzae as a cause of pediatric meningitis in northwestern Ontario
Abstract
“Before the introduction of the conjugate vaccine, Haemophilus influenzae serotype b (Hib) was the leading cause of bacterial meningitis in children. Although successful in reducing Hib cases, the vaccine confers no protection against other serotypes of H influenzae, such as a (Hia), or f (Hif). The emergence of invasive disease caused by non-Hib in northwestern Ontario (38 cases between 2002 and 2008) with predominance of Hia was previously reported by the authors. At that time, no cases of pediatric meningitis caused by H influenzae were recorded in the region. Continued surveillance identified 12 new cases of invasive non-Hib between January 2009 and July 2011. Among these cases, three young children developed meningitis with severe complications caused by Hia or Hif. The present article describes these cases along with the characteristics of recent H influenzae isolates from the region, (ie, their genetic background and antibiotic sensitivity). The findings point to the clonal nature of circulating Hia strains as well as to an increase in frequency and severity of pediatric invasive H influenzae infections in northwestern Ontario. Avant l’adoption du vaccin conjugué, l’Haemophilus influenzae de sérotype b (Hib) était la principale cause de méningite bactérienne chez les enfants. Le vaccin a réussi à réduire les cas de Hib, mais il ne confère aucune protection contre les autres sérotypes du H influenzae, tels que le sérotype a (Hia) ou le sérotype f (Hif). Les auteurs ont déjà signalé l’émergence d’une maladie invasive de sérotype non-b au nord-ouest de l’Ontario (38 cas entre 2002 et 2008), à prédominance de Hia. À l’époque, aucun cas de méningite pédiatrique causée par le H influenzae n’avait été déclaré dans la région. La surveillance continue a permis de dépister 12 nouveaux cas de H influenzae invasif de sérotype non-b entre janvier 2009 et juillet 2011. Parmi ces cas, trois jeunes enfants ont contracté une méningite accompagnée de graves complications causées par le Hia ou le Hif. Le présent article décrit ces cas ainsi que les caractéristiques des récents isolats de H influenzae dans la région (c’est-à-dire leurs antécédents génétiques et leur sensibilité aux antibiotiques). Les observations font croire à la nature clonale des souches de Hia en circulation ainsi qu’à une augmentation de la fréquence et de la gravité des infections invasives à H influenzae en pédiatrie au nordouest de l’Ontario”
Links
https://www.ncbi.nlm.nih.gov/pubmed/24421786
Citation
Emergence of Non-serotype B Encapsulated Haemophilus Influenzae as a Cause of Pediatric Meningitis in Northwestern Ontario." The Canadian Journal of Infectious Diseases & Medical Microbiology Journal Canadien Des Maladies Infectieuses Et De La Microbiologie Medicale. U.S. National Library of Medicine
“Before the introduction of the conjugate vaccine, Haemophilus influenzae serotype b (Hib) was the leading cause of bacterial meningitis in children. Although successful in reducing Hib cases, the vaccine confers no protection against other serotypes of H influenzae, such as a (Hia), or f (Hif). The emergence of invasive disease caused by non-Hib in northwestern Ontario (38 cases between 2002 and 2008) with predominance of Hia was previously reported by the authors. At that time, no cases of pediatric meningitis caused by H influenzae were recorded in the region. Continued surveillance identified 12 new cases of invasive non-Hib between January 2009 and July 2011. Among these cases, three young children developed meningitis with severe complications caused by Hia or Hif. The present article describes these cases along with the characteristics of recent H influenzae isolates from the region, (ie, their genetic background and antibiotic sensitivity). The findings point to the clonal nature of circulating Hia strains as well as to an increase in frequency and severity of pediatric invasive H influenzae infections in northwestern Ontario. Avant l’adoption du vaccin conjugué, l’Haemophilus influenzae de sérotype b (Hib) était la principale cause de méningite bactérienne chez les enfants. Le vaccin a réussi à réduire les cas de Hib, mais il ne confère aucune protection contre les autres sérotypes du H influenzae, tels que le sérotype a (Hia) ou le sérotype f (Hif). Les auteurs ont déjà signalé l’émergence d’une maladie invasive de sérotype non-b au nord-ouest de l’Ontario (38 cas entre 2002 et 2008), à prédominance de Hia. À l’époque, aucun cas de méningite pédiatrique causée par le H influenzae n’avait été déclaré dans la région. La surveillance continue a permis de dépister 12 nouveaux cas de H influenzae invasif de sérotype non-b entre janvier 2009 et juillet 2011. Parmi ces cas, trois jeunes enfants ont contracté une méningite accompagnée de graves complications causées par le Hia ou le Hif. Le présent article décrit ces cas ainsi que les caractéristiques des récents isolats de H influenzae dans la région (c’est-à-dire leurs antécédents génétiques et leur sensibilité aux antibiotiques). Les observations font croire à la nature clonale des souches de Hia en circulation ainsi qu’à une augmentation de la fréquence et de la gravité des infections invasives à H influenzae en pédiatrie au nordouest de l’Ontario”
Links
https://www.ncbi.nlm.nih.gov/pubmed/24421786
Citation
Emergence of Non-serotype B Encapsulated Haemophilus Influenzae as a Cause of Pediatric Meningitis in Northwestern Ontario." The Canadian Journal of Infectious Diseases & Medical Microbiology Journal Canadien Des Maladies Infectieuses Et De La Microbiologie Medicale. U.S. National Library of Medicine
4. Increasing Incidence of Invasive Haemophilus infl uenzae Disease in Adults, Utah, USA
Abstract
“Since the introduction of the Haemophilus infl uenzae type b vaccine, the incidence of invasive H. infl uenzae type b disease among children has fallen dramatically, but the effect on invasive H. infl uenzae disease among adults may be more complex. In this population-based study we examined the epidemiology and outcomes of invasive disease caused by typeable and nontypeable H. infl uenzae among Utah adults during 1998–2008. The overall incidence increased over the study period from 0.14/100,000 person-years in 1998 to 1.61/100,000 person-years in 2008. The average incidence in persons >65 years old was 2.74/100,000 personyears, accounting for 51% of cases and 67% of deaths. The incidence was highest for nontypeable H. infl uenzae (0.23/100,000 person-years), followed by H. infl uenzae type f (0.14/100,000 person-years). The case-fatality rate was 22%. The incidence of invasive H. infl uenzae infection in Utah adults appears to be increasing. Invasive H. infl uenzae disproportionately affected the elderly and was associated with a high mortality rate”
Links
https://www.ncbi.nlm.nih.gov/pubmed/21888789
Citation
Rubacj, Matthew. "Increasing Incidence of Invasive Haemophilus Influenzae Disease in Adults, Utah, USA." Emerging Infectious Diseases 17.9 (2011): 1645-650
“Since the introduction of the Haemophilus infl uenzae type b vaccine, the incidence of invasive H. infl uenzae type b disease among children has fallen dramatically, but the effect on invasive H. infl uenzae disease among adults may be more complex. In this population-based study we examined the epidemiology and outcomes of invasive disease caused by typeable and nontypeable H. infl uenzae among Utah adults during 1998–2008. The overall incidence increased over the study period from 0.14/100,000 person-years in 1998 to 1.61/100,000 person-years in 2008. The average incidence in persons >65 years old was 2.74/100,000 personyears, accounting for 51% of cases and 67% of deaths. The incidence was highest for nontypeable H. infl uenzae (0.23/100,000 person-years), followed by H. infl uenzae type f (0.14/100,000 person-years). The case-fatality rate was 22%. The incidence of invasive H. infl uenzae infection in Utah adults appears to be increasing. Invasive H. infl uenzae disproportionately affected the elderly and was associated with a high mortality rate”
Links
https://www.ncbi.nlm.nih.gov/pubmed/21888789
Citation
Rubacj, Matthew. "Increasing Incidence of Invasive Haemophilus Influenzae Disease in Adults, Utah, USA." Emerging Infectious Diseases 17.9 (2011): 1645-650
5. Invasive Haemophilus influenzae in British Columbia: non-Hib and non-typeable strains causing disease in children and adults
Abstract
“Objectives:
To characterize invasive Haemophilus influenzae and to examine the population at risk for invasive H. influenzae disease in British Columbia, Canada, 2008–2009.
Methods:
H. influenzae recovered from individual patients were characterized by serotyping, biotyping, multilocus sequence typing (MLST), and antibiotic susceptibility testing. Age information was recorded from specimen requisition forms.
Results:
Of the 98 cases, 66% were caused by non-typeable strains, followed by serotypes b (12%), a (10%), f (10%), and e (1%). Cases caused by serotypes b and f and non-typeable strains were mainly in adults over 18 years of age, while cases due to serotype a were mainly in children under the age of 2 years. Different sequence types were found in encapsulated strains according to their serotypes, and non-typeable strains had their own unique sequence types. No capsule switching was documented. Antibiotic resistance was common among non-typeable strains, with 31% identified as genotypic b-lactamasenegative ampicillin-resistant (BLNAR) strains.
Conclusion:
Invasive H. influenzae disease in a population vaccinated against Hib was age-dependent and involved both non-typeable and encapsulated strains. Adults were susceptible to invasive diseases due to non-typeable and serotype b and f strains, while in children, most diseases were due to serotype a bacteria.”
Links
https://www.ncbi.nlm.nih.gov/pubmed/21134777
Citation
Shuel, Michelle, Linda Hoang, Dennis K.s. Law, and Raymond Tsang. "Invasive Haemophilus Influenzae in British Columbia: Non-Hib and Non-typeable Strains Causing Disease in Children and Adults." International Journal of Infectious Diseases 15.3 (2011)
“Objectives:
To characterize invasive Haemophilus influenzae and to examine the population at risk for invasive H. influenzae disease in British Columbia, Canada, 2008–2009.
Methods:
H. influenzae recovered from individual patients were characterized by serotyping, biotyping, multilocus sequence typing (MLST), and antibiotic susceptibility testing. Age information was recorded from specimen requisition forms.
Results:
Of the 98 cases, 66% were caused by non-typeable strains, followed by serotypes b (12%), a (10%), f (10%), and e (1%). Cases caused by serotypes b and f and non-typeable strains were mainly in adults over 18 years of age, while cases due to serotype a were mainly in children under the age of 2 years. Different sequence types were found in encapsulated strains according to their serotypes, and non-typeable strains had their own unique sequence types. No capsule switching was documented. Antibiotic resistance was common among non-typeable strains, with 31% identified as genotypic b-lactamasenegative ampicillin-resistant (BLNAR) strains.
Conclusion:
Invasive H. influenzae disease in a population vaccinated against Hib was age-dependent and involved both non-typeable and encapsulated strains. Adults were susceptible to invasive diseases due to non-typeable and serotype b and f strains, while in children, most diseases were due to serotype a bacteria.”
Links
https://www.ncbi.nlm.nih.gov/pubmed/21134777
Citation
Shuel, Michelle, Linda Hoang, Dennis K.s. Law, and Raymond Tsang. "Invasive Haemophilus Influenzae in British Columbia: Non-Hib and Non-typeable Strains Causing Disease in Children and Adults." International Journal of Infectious Diseases 15.3 (2011)
6. Prevention of Haemophilus influenzae Type b (Hib) Meningitis and Emergence of Serotype Replacement with Type a Strains after Introduction of Hib Immunization in Brazil
Abstract
“Surveillance for Haemophilus influenzae meningitis cases was performed in Salvador, Brazil, before and after introduction of H. influenzae type b (Hib) immunization. The incidence of Hib meningitis decreased 69% during the 1-year period after initiation of Hib immunization (from 2.62 to 0.81 cases/100,000 person-years; P<.001). In contrast, the incidence for H. influenzae type a meningitis increased 8-fold (from 0.02 to 0.16 cases/100,000 person-years; P=.008). Pulsed-field gel electrophoretic analysis demonstrated that H. influenzae type a isolates belonged to 2 clonally related groups, both of which were found before Hib immunization commenced. Therefore, Hib immunization contributed to an increased risk for H. influenzae type a meningitis through selection of circulating H. influenzae type a clones. The risk attributable to serotype replacement is small in comparison to the large reduction in Hib meningitis due to immunization. However, these findings highlight the need to maintain surveillance as the use of conjugate vaccines expands worldwide.”
Links
https://www.ncbi.nlm.nih.gov/pubmed/12508153
Citation
Ribeiro, Guilherme S., Joice N. Reis, Soraia M. Cordeiro, Josilene B. T. Lima, Edilane L. Gouveia, Maya Petersen, Kátia Salgado, Hagamenon R. Silva, Rosemeire Cobo Zanella, Samanta C. Grassi Almeida, Maria Cristina Brandileone, Mitermayer G. Reis, and Albert I. Ko. "Prevention OfHaemophilus InfluenzaeType B (Hib) Meningitis and Emergence of Serotype Replacement with Type a Strains after Introduction of Hib Immunization in Brazil." The Journal of Infectious Diseases 187.1 (2003)
“Surveillance for Haemophilus influenzae meningitis cases was performed in Salvador, Brazil, before and after introduction of H. influenzae type b (Hib) immunization. The incidence of Hib meningitis decreased 69% during the 1-year period after initiation of Hib immunization (from 2.62 to 0.81 cases/100,000 person-years; P<.001). In contrast, the incidence for H. influenzae type a meningitis increased 8-fold (from 0.02 to 0.16 cases/100,000 person-years; P=.008). Pulsed-field gel electrophoretic analysis demonstrated that H. influenzae type a isolates belonged to 2 clonally related groups, both of which were found before Hib immunization commenced. Therefore, Hib immunization contributed to an increased risk for H. influenzae type a meningitis through selection of circulating H. influenzae type a clones. The risk attributable to serotype replacement is small in comparison to the large reduction in Hib meningitis due to immunization. However, these findings highlight the need to maintain surveillance as the use of conjugate vaccines expands worldwide.”
Links
https://www.ncbi.nlm.nih.gov/pubmed/12508153
Citation
Ribeiro, Guilherme S., Joice N. Reis, Soraia M. Cordeiro, Josilene B. T. Lima, Edilane L. Gouveia, Maya Petersen, Kátia Salgado, Hagamenon R. Silva, Rosemeire Cobo Zanella, Samanta C. Grassi Almeida, Maria Cristina Brandileone, Mitermayer G. Reis, and Albert I. Ko. "Prevention OfHaemophilus InfluenzaeType B (Hib) Meningitis and Emergence of Serotype Replacement with Type a Strains after Introduction of Hib Immunization in Brazil." The Journal of Infectious Diseases 187.1 (2003)