Invasive pneumococcal disease in hospitalised children from Lima, Peru before and after introduction of the 7-valent conjugated vaccine.

The objective of this study was to determine the serotype distribution and antibiotic resistance of invasive pneumococcal disease (IPD) strains in children from Lima, Peru, before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7), which was introduced in the national immunisation program on 2009. We conducted a prospective, multicentre, passive surveillance IPD study during 2006-2008 and 2009-2011, before and right after the introduction of PCV7 in Peru. The study was performed in 11 hospitals and five private laboratories in Lima, Peru, in patients <18 years old, with sterile site cultures yielding Streptococcus pneumoniae. In total 159 S. pneumoniae isolates were recovered. There was a decrease in the incidence of IPD in children <2 years old after the introduction of PCV7 (18.4/100 000 vs. 5.1/100 000, P = 0.004). Meningitis cases decreased significantly in the second period (P = 0.036) as well as the overall case fatality rate (P = 0.025), including a decreased case fatality rate of pneumonia (16.3% to 0%, P = 0.04). PCV7 serotypes showed a downward trend. Vaccine-preventable serotypes caused 78.9% of IPD cases, mainly 14, 6B, 5, 19F and 23F. A non-significant increase in erythromycin resistance was reported. Our findings suggest that the introduction of PCV7 led to a significant decrease of IPD in children under 2 years old and in the overall case fatality rate.

Multiplex real-time PCR for detection of Campylobacter, Salmonella, and Shigella.

Infectious diarrhea can be classified based on its clinical presentation as noninflammatory or inflammatory disease. In developing countries, among inflammatory diarrhea cases, Shigella is the most common cause, followed by Campylobacter and Salmonella. Because the time frame in which treatment choices must be made is short and conventional stool cultures lack good sensitivity, there is a need for a rapid, sensitive, and inexpensive detection technique. The purpose of our study was to develop a multiplex real-time PCR procedure to simultaneously identify Campylobacter spp., Salmonella spp., and Shigella spp. Primers were designed to amplify the invA, ipaH, and 16S rRNA genes simultaneously in a single reaction to detect Salmonella, Shigella, and Campylobacter, respectively. Using this approach, we correctly identified 102 of 103 strains of the targeted enteropathogens and 34 of 34 other pathogens. The melting temperatures were 82.96 ± 0.05 °C for invA, 85.56 ± 0.28 °C for ipaH, and 89.21 ± 0.24 °C for 16S rRNA. The limit of accurate quantification for the assay in stool samples was 10(4) CFU g(-1); however, the limit of detection was 10(3) CFU g(-1). This assay is a simple, rapid, inexpensive, and reliable system for the practical detection of these three enteropathogens in clinical specimens.