A Population-Based Assessment of the Impact of 7- and 13-Valent Pneumococcal Conjugate Vaccines on Macrolide-Resistant Invasive Pneumococcal Disease: Emergence and Decline of Streptococcus pneumoniae Serotype 19A (CC320) With Dual Macrolide Resistance Mechanisms.

BACKGROUND: Macrolide efflux encoded by mef(E)/mel and ribosomal methylation encoded by erm(B) confer most macrolide resistance in Streptococcus pneumoniae. Introduction of the heptavalent pneumococcal conjugate vaccine (PCV7) in 2000 reduced macrolide-resistant invasive pneumococcal disease (MR-IPD) due to PCV7 serotypes (6B, 9V, 14, 19F, and 23F). METHODS: In this study, the impact of PCV7 and PCV13 on MR-IPD was prospectively assessed. A 20-year study of IPD performed in metropolitan Atlanta, Georgia, using active, population-based surveillance formed the basis for this study. Genetic determinants of macrolide resistance were evaluated using established techniques. RESULTS: During the decade of PCV7 use (2000-2009), MR-IPD decreased rapidly until 2002 and subsequently stabilized until the introduction of PCV13 in 2010 when MR-IPD incidence decreased further from 3.71 to 2.45/100000 population. In 2003, serotype 19A CC320 isolates containing both mef(E)/mel and erm(B) were observed and rapidly expanded in 2005-2009, peaking in 2010 (incidence 1.38/100000 population), accounting for 36.1% of MR-IPD and 11.7% of all IPD isolates. Following PCV13 introduction, dual macrolide-resistant IPD decreased 74.1% (incidence 0.32/100000 in 2013). However, other macrolide-resistant serotypes (eg, 15A and 35B) not currently represented in PCV formulations increased modestly. CONCLUSIONS: The selective pressures of widespread macrolide use and PCV7 and PCV13 introductions on S. pneumoniae were associated with changes in macrolide resistance and the molecular basis over time in our population. Durable surveillance and programs that emphasize the judicious use of antibiotics need to continue to be a focus of public health strategies directed at S. pneumoniae.

Predictors of first follow-up HIV testing for couples' voluntary HIV counseling and testing in Ndola, Zambia.

INTRODUCTION: We describe predictors of first follow-up testing for concordant negative and discordant couples seeking joint voluntary HIV counseling and testing in Ndola, Zambia, where cohabiting couples account for an estimated two-thirds of incident HIV infections. METHODS: Demographic and serostatus data were collected from couples' voluntary HIV testing and counseling and follow-up testing services implemented in government clinics. We calculated follow-up testing rates by serostatus and compared rates before and after the introduction of a Good Health Package (GHP). RESULTS: The follow-up testing rate from May 2011 to December 2012 was 12.2% for concordant negative (M-F-) couples and 24.5% for discordant (M+F- or M-F+) couples. Significant predictors of follow-up testing in multivariate analyses included increasing age of the man [adjusted odds ratio (aOR) = 1.02 per year] and the woman (aOR = 1.02 per year), and either partner being HIV+ (aOR = 2.57 for HIV+ man, aOR = 1.89 for HIV+ woman). The man (aOR = 1.29) and the couple (aOR = 1.22) having been previously tested for HIV were predictive of follow-up testing among concordant negative couples. Introduction of a GHP increased follow-up testing among discordant (aOR = 2.93) and concordant negative (aOR = 2.06) couples. CONCLUSIONS: A low-cost GHP, including prevention, screening, and treatment for common causes of morbidity and mortality resulted in increased follow-up testing rates among HIV discordant and concordant negative couples. Overall follow-up testing rates remain low, and efforts to increase these rates are necessary to ensure linkage to combination prevention, reduce HIV transmission within couples, and identify seroconversions promptly. Further investigation of low-cost sustainable incentives and other factors influencing follow-up HIV testing for couples is needed.