BACKGROUND: Because pneumococcal serotype 6C was previously not distinguished from serotype 6A, the impact of the 7-valent pneumococcal conjugate vaccine (PCV7) on the carriage of serotype 6C is unknown. METHODS: The nasopharyngeal (NP) prevalence of the 6C serotype was determined using 1326 pneumococcal isolates collected from 7 cohorts of Massachusetts children between 1994 and 2007. Initially, the isolates were serotyped using the quellung reaction; subsequently, stored specimens of all putative 6A isolates were tested for 6C using monoclonal antibodies. The opsonophagocytic and antibiotic susceptibilities of the isolates were determined. RESULTS: The prevalence of 6A was 9.6% (33/343) before 2001, 8.0% (18/226) in 2004, and 2.9% (12/416) in 2007. In contrast, the prevalence of 6C was 0.6% (2/343) before 2001, 2.2% (5/226) in 2004, and 8.7% (36/416) in 2007 (P<.001 for 2/343 vs. 36/416). 6C isolates from 2007 were more susceptible to antibiotics than were 6A isolates. PCV7 induced a low ability to opsonize different isolates of 6C. CONCLUSIONS: Among NP isolates, the prevalence of 6C isolates has increased and the prevalence of 6A isolates has decreased since the introduction of PCV7 in Massachusetts in 2000. The observed increase in serotype 6C prevalence may be explained by the induction by PCV7 of low amounts of functional anti-6C antibody, compared with anti-6A and anti-6B antibodies.
BACKGROUND: Because pneumococcal serotype 6C was previously not distinguished from serotype 6A, the impact of the 7-valent pneumococcal conjugate vaccine (PCV7) on the carriage of serotype 6C is unknown. METHODS: The nasopharyngeal (NP) prevalence of the 6C serotype was determined using 1326 pneumococcal isolates collected from 7 cohorts of Massachusetts children between 1994 and 2007. Initially, the isolates were serotyped using the quellung reaction; subsequently, stored specimens of all putative 6A isolates were tested for 6C using monoclonal antibodies. The opsonophagocytic and antibiotic susceptibilities of the isolates were determined. RESULTS: The prevalence of 6A was 9.6% (33/343) before 2001, 8.0% (18/226) in 2004, and 2.9% (12/416) in 2007. In contrast, the prevalence of 6C was 0.6% (2/343) before 2001, 2.2% (5/226) in 2004, and 8.7% (36/416) in 2007 (P<.001 for 2/343 vs. 36/416). 6C isolates from 2007 were more susceptible to antibiotics than were 6A isolates. PCV7 induced a low ability to opsonize different isolates of 6C. CONCLUSIONS: Among NP isolates, the prevalence of 6C isolates has increased and the prevalence of 6A isolates has decreased since the introduction of PCV7 in Massachusetts in 2000. The observed increase in serotype 6C prevalence may be explained by the induction by PCV7 of low amounts of functional anti-6C antibody, compared with anti-6A and anti-6B antibodies.
Authors: S Black; H Shinefield; B Fireman; E Lewis; P Ray; J R Hansen; L Elvin; K M Ensor; J Hackell; G Siber; F Malinoski; D Madore; I Chang; R Kohberger; W Watson; R Austrian; K Edwards Journal: Pediatr Infect Dis J Date: 2000-03 Impact factor: 2.129
Authors: Susan S Huang; Richard Platt; Sheryl L Rifas-Shiman; Stephen I Pelton; Donald Goldmann; Jonathan A Finkelstein Journal: Pediatrics Date: 2005-09 Impact factor: 7.124
Authors: R Dagan; R Melamed; M Muallem; L Piglansky; D Greenberg; O Abramson; P M Mendelman; N Bohidar; P Yagupsky Journal: J Infect Dis Date: 1996-12 Impact factor: 5.226
Authors: In H Park; Matthew R Moore; John J Treanor; Stephen I Pelton; Tamara Pilishvili; Bernard Beall; Mark A Shelly; Barbara E Mahon; Moon H Nahm Journal: J Infect Dis Date: 2008-12-15 Impact factor: 5.226
Authors: Catherine Satzke; Belinda D Ortika; Shahin Oftadeh; Fiona M Russell; Roy M Robins-Browne; E Kim Mulholland; Gwendolyn L Gilbert Journal: J Clin Microbiol Date: 2010-09-01 Impact factor: 5.948
Authors: William P Hanage; Jonathan A Finkelstein; Susan S Huang; Stephen I Pelton; Abbie E Stevenson; Ken Kleinman; Virginia L Hinrichsen; Christophe Fraser Journal: Epidemics Date: 2010-06 Impact factor: 4.396
Authors: Michael R Jacobs; Ron Dagan; Saralee Bajaksouzian; Anne R Windau; Nurith Porat Journal: J Clin Microbiol Date: 2010-02-17 Impact factor: 5.948
Authors: Stephen I Pelton; Melinda M Pettigrew; Stephen J Barenkamp; Fabrice Godfroid; Carlos G Grijalva; Amanda Leach; Janak Patel; Timothy F Murphy; Sanja Selak; Lauren O Bakaletz Journal: Otolaryngol Head Neck Surg Date: 2013-04 Impact factor: 3.497