Resistance to antibiotics at pathog...

Resistance to antibiotics at pathogens is an increasingly serious point to be solved [i]or[/i] settled worldwide. By 1999, approximately 25 percent of isolates from invasive infections caused by the agency of Streptococcus pneumoniae in the United States and many other countries were resistant to macrolides. This rapid increase followed the introduction of the recent macrolides azithromycin (Zithromax) and clarithromycin (Biaxin). Macrolide resistance was predominantly reported in pneumococcal serotype 14 19F 19A, 6B 6A, and 23F Four of these subtype (6B 14 23F and 19F) were targeted in the 7-valent pneumococcal conjugate vaccine (Prevnar) introduced for use in young children in the United States in 2000 Stephens and colleagues studied the impact of the vaccine upon macrolide resistance in invasive pneumococcal disease.

The authors used data from prospective, population-based surveillance hypothesiss that provided information about patient characteristics and the pneumococcal organisms involved in all invasive pneumococcal disease in the Atlanta metropolitan area since 1994 The thought included all samples in which pneumococci were grown from normally sterile sites as it was as blood or cerebrospinal fluid (CSF) Data onward invasive pneumococcal disease were correlated with information forward coverage of pneumococcal immunization obtained from national surveys

Between 1994 and 2002 researchers identified 6695 invasive pneumococcal infections. The proportion of isolates available for testing ranged from 77 to 87 percent returning episodes of infection in the same patient were judgeed as separate infections. Blood accounted for 95 percent of isolates, with 35 percent from CSF or CSF and posterity and 1.5 percent from joints, pleural fluid, and other sites. The mean annual incidence of invasive pneumococcal disease decreased from 302 infections for 100,000 persons from 1994 to 1999 to 131 infections through 100,000 persons in 2002. The decline was principally evident in children younger than couple years. In this age cluster the incidence of invasive pneumococcal disease decreased 82 percent from the mean annual incidence of 278 infections through 100,000 persons from 1994 to 1999 to 50 infections by means of 100,000 persons in 2002. In children pair to four years of age, there was a 71 percent decrease. Adults had decreases of 54 percent in patients 20 to 39 years of age, 25 percent in patients 40 to 64 years of age, and 39 percent in patients 65 years and older The incidence of invasive pneumococcal disease decreased according to 63 percent in blacks and 54 percent in whites. Substantial decreases were documented for vaccine serotype 14 (92 percent) 6B (53 percent) 19F (84 percent) and 23F (76 percent)

Three years after the pneumococcal vaccination was introduced in the United States, an estimated 80 percent of U children 19 to 35 month of age had received sum of two units doses, but less than 30 percent received the cloyed four-dose series. In the six years before the vaccine was introduced (1994 to 1999) the incidence of macrolide-resistant disease grew rapidly to 93 by 100,000. By 2002, the incidence of macrolide-resistant disease decreased to 29 by means of 100,000. The change was most numerous dramatic in children younger than sum of two units years of age, in whom a decrease of 85 percent was noted. Significant decreases also were reported in other age clumps and in blacks and whites.

The authors end that the introduction of pneumococcal vaccination was associated with dramatic decreases in the incidence of invasive pneumococcal disease, particularly in the targeted population collections and in disease caused from the vaccine serotypes. They attribute the changes in antibiotic resistance to the vaccination by means of direct and indirect (i.e., herd immunity) validitys The decline is predominantly a flow of decreased incidence in the serotype commonly associated with macrolide and other antibiotic resistance. Nevertheless, selective urgency for macrolide resistance persists in the serotype not affected according to the vaccine and in different mechanisms on which the organism develops and spreads resistance. newly come monitoring shows increasing resistance in serotype 14 9A, and 33 The authors call for greater efforts to increase vaccination coverage and for continued monitoring of resistance patterns in the pneumococcal organism.

Stephens D et al. Incidence of macrolide resistance in Streptococcus pneumoniae after introduction of the pneumococcal conjugate vaccine: population-based assessment. Lancet March 5 2005;365:855-63

ANNE D WALLING, MD

COPYRIGHT 2005 American Academy of Family Physicians

COPYRIGHT 2006 Gale Group