Both Optimal Matching and Procedure Duration Influence Survival of Patients after Unrelated Donor Hematopoietic Stem Cell Transplantation

Eighty-six patients suffering from hematological malignancies, immunodeficiencies, and aplastic anemias received alloHSCT from unrelated donors. Donors were selected from the BMDW files and further matching was performed according to the confirmatory typing procedure with the use of PCR SSP and that based on sequencing. The time from the clinical request of the donor search to the final decision of clinicians accepting the donor was from 0.3 to 17.8 months (median 1.6). Matching was analyzed at the allele level, and 50, 27, and 9 donor-recipient pairs were 10/10 matched, mismatched in one or more alleles, respectively. In an univariate analysis we found better survival if patients were transplanted: (i) from donors matched 10/10 (P=0.025), (ii) not from female donor to male recipient (P=0.037), (iii) in female donation from those with ≤1 pregnancy than multiparous (P=0.075). Notably, it became apparent that duration of the confirmatory typing process affected the survival (HR = 1.138, P=0.013). In multivariate analysis only the level of matching and the duration of the matching procedure significantly affected the survival. In conclusion, the duration of the matching procedure in addition to the level of matching should be considered as an independent risk factor of survival.

Identification of the Major Spanish Clones of Penicillin-Resistant Pneumococci via the Internet Using Multilocus Sequence Typing

Multilocus sequence typing was used to characterize isolates of the major Spanish clones of penicillin-resistant and multiple-antibiotic-resistant Streptococcus pneumoniae. Isolates of the multidrug-resistant Spanish serotype 23F clone and serotype variants of this clone either had identical allelic profiles or their allelic profiles differed from this typical allelic profile at only one of the seven housekeeping loci. Similarly, isolates of the Spanish serotype 6B and 14 clones and the penicillin-resistant serotype 9V clone (and serotype variants of this clone) each had the same allelic profiles or profiles that differed at a single locus. Multilocus sequence typing therefore allows resistant pneumococci to be assigned to the Spanish clones if they have the typical allelic profile of the clone or if their profiles differ from that profile at a single locus. A few resistant isolates that had allelic profiles typical of that of a Spanish clone or whose profiles differed from that of the typical profile at only a single locus possessed penicillin-binding protein pbp1a, pbp2b, or pbp2xgenes that differed from those that are characteristic of the clone. In most cases these isolates could be assigned as variant members of the clone. Since almost all serotype 9V isolates have very similar genotypes, independently emerging penicillin-resistant clones of this serotype will inevitably appear to be similar by molecular typing procedures. Analysis of the pbp genes, in addition to multilocus sequence typing (or any other molecular typing procedure), is therefore required to assign isolates unambiguously to the penicillin-resistant Spanish serotype 9V clone.

Identification of Three Major Clones of Multiply Antibiotic-Resistant Streptococcus pneumoniae in Taiwanese Hospitals by Multilocus Sequence Typing

In this paper we demonstrate the advantages of a new molecular typing procedure, multilocus sequence typing, for the unambiguous characterization of penicillin-resistant pneumococci. The sequences of ∼450-bp fragments of seven housekeeping genes were determined for 74 penicillin-resistant Taiwanese isolates of Streptococcus pneumoniae (MIC of penicillin > 0.5 μg/ml). The combination of alleles at the seven loci defined an allelic profile for each strain, and a dendrogram, based on the pairwise mismatches in allelic profiles, grouped 86% of the isolates into one of three penicillin-resistant clones for which the MICs of penicillin were 1 to 2 μg/ml. Isolates within each clone had identical alleles at all seven loci or differed at only a single locus, and the fingerprints of their pbp1A, pbp2B, and pbp2X genes were uniform. Isolates of the Taiwan-19F clone and the Taiwan-23F clone were resistant to penicillin, tetracycline, and erythromycin but were susceptible to chloramphenicol. A second serotype 23F clone and serotype 19F variants of this clone were resistant to penicillin, tetracycline, chloramphenicol, and, in some cases, erythromycin. Comparisons of the allelic profiles of the three major clones with those of reference isolates of the known penicillin-resistant clones showed that the Taiwan-19F and Taiwan-23F clones were previously undescribed, whereas the second serotype 23F clone was indistinguishable from the Spanish multidrug-resistant serotype 23F clone. Single isolates of the Spanish penicillin-resistant serotype 9V clone and the Spanish multidrug-resistant serotype 6B clone were also identified in the collection.