Nationwide Surveillance of Nasopharyngeal<i>Streptococcus pneumoniae</i>Isolates from Children with Respiratory Infection, Switzerland, 1998–1999

Mühlemann, Kathrin; Matter, Hans C.; Täuber, Martin G.

doi:10.1086/367994

Cited by 57 publications

(66 citation statements)

References 20 publications

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“…Serotype 3 isolates from a number of countries, including Taiwan, Japan, and Switzerland, have been shown to have lower rates of antimicrobial resistance (17,19,26). The majority of South African isolates displayed a similar trend by showing susceptibility to most of the antimicrobial agents tested.…”

Section: Discussionmentioning

confidence: 95%

An Unusual Pneumococcal Sequence Type Is the Predominant Cause of Serotype 3 Invasive Disease in South Africa

et al. 2010

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We reviewed pneumococcal serotype 3 cases reported from 2000 through 2005 to a laboratory-based surveillance system for invasive pneumococcal disease in South Africa. The prevalence of serotype 3 invasive isolates was compared to their prevalence in carriage isolates to determine the odds of invasiveness due to serotype 3 among South African children. Three groups of serotype 3 strains were characterized by pulsed-field gel electrophoresis (PFGE) or Box element PCR (BOX-PCR), randomly selected invasive isolates from one province, isolates from a carriage study involving children in the same province, and antimicrobial-resistant invasive isolates collected nationally. Examples of the PFGE types identified were further characterized by multilocus sequence typing.

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Section: Discussionmentioning

confidence: 95%

An Unusual Pneumococcal Sequence Type Is the Predominant Cause of Serotype 3 Invasive Disease in South Africa

et al. 2010

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“…The invasive strains of S. pneumoniae used (an invasive strain was defined as a culture from a sterile body site) originated from nationwide collection of all invasive isolates in 1998 and 1999 (23) and between March and December 2002 (24). S. pneumoniae was grown and identified and antibiotic susceptibility was determined as described previously (19). Bacteria were routinely grown on Columbia sheep blood agar (CSBA) plates at 37°C in a 5% CO 2 -enriched atmosphere or in brain heart infusion (BHI) broth containing 5% fetal calf serum (FCS) at 37°C in ambient air and were stored at Ϫ80°C by using Protect bacterial preservers (TSC, Heywood, United Kingdom).…”

Section: Methodsmentioning

confidence: 99%

A Homologue ofaliBIs Found in the Capsule Region of NonencapsulatedStreptococcus pneumoniae

et al. 2004

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The epidemiology, phylogeny, and biology of nonencapsulated Streptococcus pneumoniae are largely unknown. Increased colonization capacity and transformability are, however, intriguing features of these pneumococci and play an important role. Twenty-seven nonencapsulated pneumococci were identified in a nationwide collection of 1,980 nasopharyngeal samples and 215 blood samples obtained between 1998 and 2002. On the basis of multilocus sequence typing and capsule region analysis we divided the nonencapsulated pneumococci into two groups. Group I was closely related to encapsulated strains. Group II had a clonal population structure, including two geographically widespread clones able to cause epidemic conjunctivitis and invasive diseases. Group II strains also carried a 1,959-bp homologue of aliB (aliB-like ORF 2) in the capsule region, which was highly homologous to a sequence in the capsule region of Streptococcus mitis. In addition, strains of the two major clones in group II had an additional sequence, aliB-like ORF 1 (1,968 to 2,004 bp), upstream of aliB-like ORF 2. Expression of aliB-like ORF 1 was detected by reverse transcription-PCR, and the corresponding RNA was visualized by Northern blotting. A gene fragment homologous to capN of serotypes 33 and 37 suggests that group II strains were derived from encapsulated pneumococci some time ago. Therefore, loss of capsule expression in vivo was found to be associated with the importation of one or two aliB homologues in some nonencapsulated pneumococci.

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“…For establishment and validation of the test, clinical isolates of S. pneumoniae were selected from two nationwide surveillance programs collecting nasopharyngeal and invasive isolates (16,23). They represented prevalent serotypes (1, 4, 6A, 6B, 9V, 14, 15, 18C, 19F, and 23F).…”

Section: Methodsmentioning

confidence: 99%

“…A total of 287 consecutive nasopharyngeal swabs were collected between December 2004 and February 2005, together with epidemiological information, within one of the above-mentioned surveillance programs (23). Swabs were streaked out onto CSBA (Columbia sheep blood agar) plates and were then put into a 1.5-ml polypropylene tube (Sarstedt, Sevelen, Switzerland) filled with 800 l of transport medium for chlamydia and viruses (TMCV) and vortexed for 30 s at maximum speed.…”

Section: Methodsmentioning

confidence: 99%

Detection of Streptococcus pneumoniae Strain Cocolonization in the Nasopharynx

2009

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Colonization with more than one distinct strain of the same species, also termed cocolonization, is a prerequisite for horizontal gene transfer between pneumococcal strains that may lead to change of the capsular serotype. Capsule switch has become an important issue since the introduction of conjugated pneumococcal polysaccharide vaccines. There is, however, a lack of techniques to detect multiple colonization by S. pneumoniae strains directly in nasopharyngeal samples. Two hundred eighty-seven nasopharyngeal swabs collected during the prevaccine era within a nationwide surveillance program were analyzed by a novel technique for the detection of cocolonization, based on PCR amplification of a noncoding region adjacent to the pneumolysin gene (plyNCR) and restriction fragment length polymorphism (RFLP) analysis. The numbers of strains and their relative abundance in cocolonized samples were determined by terminal RFLP. The pneumococcal carriage rate found by PCR was 51.6%, compared to 40.0% found by culture. Cocolonization was present in 9.5% (10/105) of samples, most (9/10) of which contained two strains in a ratio of between 1:1 and 17:1. Five of the 10 cocolonized samples showed combinations of vaccine types only (n ‫؍‬ 2) or combinations of nonvaccine types only (n ‫؍‬ 3). Carriers of multiple pneumococcal strains had received recent antibiotic treatment more often than those colonized with a single strain (33% versus 9%, P ‫؍‬ 0.025). This new technique allows for the rapid and economical study of pneumococcal cocolonization in nasopharyngeal swabs. It will be valuable for the surveillance of S. pneumoniae epidemiology under vaccine selection pressure.Streptococcus pneumoniae is among the most important of human pathogens and is responsible for bacterial meningitis, sepsis, pneumonia, and acute otitis media. The habitat of the pneumococcus is the mucosa of the human nasopharynx. Colonization of the nasopharynx occurs early in life, with a prevalence of about 40% in infants and 15% in adults (depending on the local epidemiology). A single strain can persist in the nasopharynx for weeks or months, to then be replaced by other strains. Colonization is the starting point for all relevant aspects of this pathogen, such as invasive disease, exchange of genetic material, genetic recombination, and transmission. By the age of two, more than 95% of children have been colonized with up to six different serotypes (8). Sometimes more than one pneumococcal strain colonizes the nasopharynx at the same time. This phenomenon is known as cocolonization, or multiple colonization with more than one distinct strain of the same species. Cocolonization is probably required for horizontal gene transfer between different pneumococcal strains. Such genetic exchange has been shown to occur for the capsule gene locus and has been observed in the past for dominant international multiresistant pneumococcal clones (5). There are few data on rates of multiple colonization, but existing estimates range from 1.3% (13) up to 20% (9, 26). No...

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Nationwide Surveillance of NasopharyngealStreptococcus pneumoniaeIsolates from Children with Respiratory Infection, Switzerland, 1998–1999

Cited by 57 publications

References 20 publications

An Unusual Pneumococcal Sequence Type Is the Predominant Cause of Serotype 3 Invasive Disease in South Africa

An Unusual Pneumococcal Sequence Type Is the Predominant Cause of Serotype 3 Invasive Disease in South Africa

A Homologue ofaliBIs Found in the Capsule Region of NonencapsulatedStreptococcus pneumoniae

Detection of Streptococcus pneumoniae Strain Cocolonization in the Nasopharynx

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