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New Pneumococcal Serotype 15D

2021; American Society for Microbiology; Volume: 59; Issue: 5 Linguagem: Inglês

10.1128/jcm.00329-21

1098-660X

Fabiana Cristina Pimenta, Benild Moiane, Robert E. Gertz, Sopio Chochua, Paula M. Snippes Vagnone, Ruth Lynfield, Betuel Sigaúque, María da Gloria Carvalho, Bernard Beall,

Pneumocystis jirovecii pneumonia detection and treatment

The pneumococcal serogroup 15 comprises four capsular polysaccharide serotypes (15A, 15B, 15C, 15F) that collectively account for an impactful disease burden (1, 2). These four serotypes are defined by Quellung reaction typing, employing specific serologic factor sera to visualize the capsule (3) (Table 1). Each of these four serotypes shares an identical pentasaccharide repeat unit that forms an identical linear structure in types 15A and 15F, and a distinct branched structure in types 15B and 15C (4). The two distinct repeat oligosaccharide polymerase genes, wzy15BC and wzy15AF (4), provide the basic structural difference between these two pairs of highly related serotypes (Fig. 1). The difference between serotypes 15B and 15C is dictated by O-acetylation of the polysaccharide in serotype 15B by the wciZ-encoded enzyme, with the two serotypes frequently interconverting due to reversible frameshifting of a TA repeat within wciZ (5). Similarly, the wciZ gene in serotype 15A contains multiple inactivating mutations compared to its functional counterpart in serotype 15F (4, 6). At the end of the cps15F operon is another putative O-acetyltransferase gene, wcjE (4), that potentially contributes to the serologic difference between 15A and 15F strains. The wzy primary target, combined with the wciZ secondary target, distinguishes these four serotypes in our whole-genome sequence-based pneumococcal bioinformatic pipeline (1). Note that the incomplete rhamnose biosynthetic apparatus (rmlB and rmlD) and the glf gene that encodes UDP-galactopyranose serve no apparent functions in serotype 15F (Fig. 1), since serogroup 15 capsules do not contain rhamnose or galactofuranose (7, 8).