Evolution of an International External Quality Assurance Model To Support Laboratory Investigation of Streptococcus pneumoniae , Developed for the SIREVA Project in Latin America, from 1993 to 2005

Abstract

In 1993 the Pan American Health Organization initiated a laboratory-based surveillance system, called the SIREVA project, to learn about Streptococcus pneumoniae invasive disease in Latin American children. In 1994, National Laboratories in six countries were trained to perform serotyping and antibiotic susceptibility testing using broth microdilution to determine the MIC for specified antibiotics. An international External Quality Assurance (EQA) program was developed to monitor and support ongoing laboratory performance. The EQA program was coordinated by the National Centre for Streptococcus (NCS), Edmonton, Canada, and included external proficiency testing (EPT) and a validation process requiring regular submission of a sample of isolates from each laboratory to the NCS for verification of the serotype and MIC. In 1999, the EQA program was decentralized to use three of the original laboratories as regional quality control centers to address operational concerns and to accommodate the growth of the laboratory network to more than 20 countries including the Caribbean region. The overall EPT serotyping accuracies for phase I (1993 to 1998) and phase II (1999 to 2005) were 88.0 and 93.8%, respectively; the MIC correlations within ؎1 log 2 dilution of the expected result were 83.0 and 91.0% and the interpretive category agreements were 89.1 and 95.3%. Overall, the validation process serotyping accuracies for phases I and II were 81.9 and 88.1%, respectively, 80.4 and 90.5% for MIC agreement, and 85.8 and 94.3% for category agreement. These results indicate a high level of testing accuracy in participating National Laboratories and a sustained increase in EQA participation in Latin America and the Caribbean.The impact of childhood pneumonia caused by Streptococcus pneumoniae in the developing world is well recognized; however, until recently, the epidemiology of invasive pneumococcal disease in Latin America was poorly documented (3, 4, 8). The growing rates of antibiotic-resistant S. pneumoniae worldwide, combined with the promise of new conjugate pneumococcal vaccines, prompted the Pan American Health Organization/World Health Organization (PAHO/WHO) to initiate an international laboratory-based surveillance network that would provide prospective regional serotype prevalence data, antibiotic resistance rates, and epidemiology of invasive pneumococcal disease in Latin American children. In 1993, with significant funding from the Canadian International Development Agency, the National Centre for Streptococcus (NCS), Edmonton, Alberta, Canada, and the Laboratory Centre for Disease Control, Ottawa, Ontario, Canada, were recruited to provide laboratory and epidemiological support for this new project (3,4,8). As part of the PAHO/WHO Sistema Regional de Vacunas, the project became known as SIREVA (8).The establishment of specific goals to guide the SIREVA project was integral to successful development of the quality program: (i) to produce study data accepted as valid by the international community; (ii) to create an ...

The International Circumpolar Surveillance Interlaboratory Quality Control Program for Streptococcus pneumoniae , 1999 to 2008

“…Konradsen et al (8) evaluated the quality of serotyping of pneumococci among 11 reference laboratories in Europe and found a serotype concordance of 95%. An international EQA program developed to monitor and support ongoing laboratory performance of serotyping and antibiotic susceptibility testing for S. pneumoniae in Latin America found overall rates of serotype concordance of 88% and 93.8% for phase I (1994 to 1998) and phase II (1999 to 2005) of the program, respectively (9). These results are comparable to the overall serotyping concordance of 95.8% that we identified in the ICS QC program.…”

“…Similar results for erythromycin (68.7%) were reported in the Latin American study (9). The wide variation in MICs was most likely due to the CO 2 environment required for testing of S. pneumoniae with the Etest.…”

“…The ICS QC program did not report results for oxacillin disk diffusion screening; however, the rates of modal MIC and categorical concordance were 100% and 99%, respectively, for penicillin, regardless of test method. Similar high levels of concordance were noted in phase II of a Latin American study, where the rates of MIC and categorical concordance for penicillin were 93.3% and 93.6%, respectively, (9). In another large international quality assurance exercise distributed by the United Kingdom National External Quality Assurance Scheme to the European Antimicrobial Resistance Surveillance System (EARSS) laboratories, concordance for penicillin-nonsusceptible isolates using the MIC method was 94%, whereas it was 79% for non-MIC-based methods (3).…”

“…Reports describing programs that evaluate pneumococcal serotyping are limited (8,9). Konradsen et al (8) evaluated the quality of serotyping of pneumococci among 11 reference laboratories in Europe and found a serotype concordance of 95%.…”

Capsular Serotyping of <em>Streptococcus pneumoniae</em> Using the Quellung Reaction

“…A high degree of concordance has been found between laboratories, and between the Quellung reaction and other serotyping methods [11][12][13] . There are several variations of the Quellung reaction 10,[14][15][16] .…”