Efficiency of Laboratory Testing for Antibiotic Resistance. A recent proficiency testing survey conducted by the American Proficiency Institute (API) assessed the ability of laboratories to detect low-level penicillin resistance in a strain of S. pneumoniae. Results revealed that antimicrobial susceptibility testing practices are suboptimal in many laboratories, particularly those using disk diffusion methods which lack adequate procedures for screening for and confirming reduced susceptibility to penicillin. Additionally it was found that unapproved antimicrobial agents were used frequently for testing against S. pneumoniae. These findings underline the importance of continued educational initiatives, as well as studies to discover the reasons why laboratories fail to follow published standards, and enforcement of the use of standards by regulatory and credentialing agencies. Edson et al. Diag. Microbio. & Inf. Dis. 2006 (In Press).
Impact of PCV7 on Invasive Pneumococcal Disease. A recent study aimed to determine the rates of invasive pneumococcal disease (IPD) in young infants aged 0 to 90 days before and after PCV7 incorporation into the childhood immunization schedule in June 2000. A prospective, population-based study was conducted on infants who resided in 8 US states with active laboratory surveillance for invasive S. pneumoniae infections from July 1, 1997 to June 30, 2004. Results from this study showed that since PCV7 introduction, rates of IPD in young infants have declined significantly. Immunizing children aged 2 to 23 months has led to changes in pneumococcal carriage in infants too young to receive PCV7, indicating that this population is benefiting from the effects of herd immunity. Additionally it was found that the racial differences in the rates of IPD between white and black infants aged 0 to 90 days had been eliminated following PCV7 introduction. Continued surveillance of IPD in this and other age groups is critical to monitor this trend as well as the emergence of potential serotypes not included in PCV7. Poehling et al. JAMA. 2006 Apr; 295(14): 1668-1674.
Outcome of Pneumococcal Vaccination in Adults. A recent study investigated the impact of prior pneumococcal vaccination on in-hospital mortality and the probability of respiratory failure among hospitalized adults with community-acquired pneumonia. Individuals diagnosed with community-acquired pneumonia at 109 community and teaching hospitals in the US were identified. Immunization status, comorbidities, and outcomes were abstracted by case managers concurrently with patient care. Associations between vaccination, survival, and respiratory failure were defined using multivariable logistic regression models. Results showed that prior vaccination against pneumococcus is associated with improved survival, decreased change of respiratory failure or other complications, and decreased length of stay among hospitalized patients with community-acquired pneumonia. These observations reinforce current efforts to improve compliance with existing pneumococcal vaccination recommendations for adults. Fisman et al. Clin. Inf. Dis. 2006 Apr; 42: 1093-1101.