Evidence for the Introduction of a Multiresistant Clone of Serotype 6B Streptococcus pneumoniae from Spain to Iceland in the Late 1980s

Abstract

Almost all of the multiresistant pneumococci that appeared suddenly in clinical specimens in Iceland between 1989 and 1992 belonged to serogroup 6. Fifty-seven of these isolates were analyzed for serotype, penicillin-binding protein pattern, multilocus enzyme genotype, and fragmentation pattern obtained by pulsed-field electrophoretic separation of restriction enzyme digests of chromosomal DNA. All isolates were of serotype 6B and had similar or identical patterns in each molecular test. The Icelandic isolates were indistinguishable from a subgroup of multiresistant serotype 6B pneumococci that has been present with high incidence in Spain during the past two decades. The data suggest the import to Iceland of a single multiresistant clone of pneumococcus, most likely from Spain.

Factors in the Emergence of Infectious Diseases

“…Other evidence indicates that cholera was only one of many organisms to travel in ballast water; dozens, perhaps hundreds, of species have been exchanged between distant places through this means of transport alone. New bacterial strains, such as the recently identified Vibrio cholerae O139, or an epidemic strain of Neisseria meningitidis (34,35) (also examples of microbial adaptation and change) have disseminated rapidly along routes of trade and travel, as have antibiotic-resistant bacteria (5,36).…”

“…The emergence of antibiotic-resistant bacteria as a result of the ubiquity of antimicrobials in the environment is an evolutionary lesson on microbial adaptation, as well as a demonstration of the power of natural selection. Selection for antibiotic-resistant bacteria (5,36) and drug-resistant parasites has become frequent, driven by the wide and sometimes inappropriate use of antimicrobial drugs in a variety of applications (27,45,46). Pathogens can also acquire new antibiotic resistance genes from other, often nonpathogenic, species in the environment (36), selected or perhaps even driven by the selection pressure of antibiotics.…”

“…Factors that promote one or both of these steps will, therefore, tend to precipitate disease emergence. Most emerging infections, and even antibiotic-resistant strains of common bacterial pathogens, usually originate in one geographic location and then disseminate to new places (5).…”

Clonal success of piliated penicillin nonsusceptible pneumococci

“…The dissemination of the Spain 6B -2 clone was the reason for the increased resistance rates observed among pneumococci between 1989 and the early to mid-1990s in Iceland (4). The Spain 9V -3 clone [sequence type (ST)156], known to be resistant to penicillin and trimethoprim-sulfametoxazole and common among pneumococci nonsusceptible to penicillin (PNSP), has been reported to spread to most countries in Europe and to be present on all continents worldwide (5).…”

Meeting the challenge: prevention of pneumococcal disease with conjugate vaccines

“…The first process is the importation and spread of a small number of resistant clones, with advantages over local strains, in an environment in which antibiotics are often misused. [53][54][55] The second is the in vivo selection of indigenous strains with modified penicillin-binding proteins (pbp), 56 either by replacement of part of pbp genes by interspecies or homologous recombinational events, or by the acquisition of point mutations in pbp genes. 52,57,58 Different non-pbp resistance mechanisms have been described for antimicrobial resistance of pneumococci, 59,60 and others that are under investigation that might play an important role in the dissemination of antimicrobial resistance, with severe clinical consequences.…”