Characterization of TEM-1 β-Lactamase-Producing Kingella kingae Clinical Isolates

Kingella kingae is a human pathogen that causes pediatric osteoarticular infections and infective endocarditis in children and adults. The bacterium is usually susceptible to β-lactam antibiotics, although β-lactam resistance has been reported in rare isolates. This study was conducted to identify β-lactam-resistant strains and to characterize the resistance mechanism. Screening of a set of 90 K. kingae clinical isolates obtained from different geographic locations revealed high-level resistance to penicillins among 25% of the strains isolated from Minnesota and Iceland. These strains produced TEM-1 β-lactamase and were shown to contain additional ≥50-kb plasmids. Ion Torrent sequencing of extrachromosomal DNA from a β-lactamase-producing strain confirmed the plasmid location of the bla_TEM gene. An identical plasmid pattern was demonstrated by multiplex PCR in all β-lactamase producers. The porin gene''s fragments were analyzed to investigate the relatedness of bacterial strains. Phylogenetic analysis revealed 27 single-nucleotide polymorphisms (SNPs) in the por gene fragment, resulting in two major clusters with 11 allele types forming bacterial-strain subclusters. β-Lactamase producers were grouped together based on por genotyping. Our results suggest that the β-lactamase-producing strains likely originate from a single plasmid-bearing K. kingae isolate that traveled from Europe to the United States, or vice versa. This study highlights the prevalence of penicillin resistance among K. kingae strains in some regions and emphasizes the importance of surveillance for antibiotic resistance of the pathogen.     

Frequency of known gene rearrangements in endometrial stromal tumors

Translocations resulting in gene fusion are characteristic of endometrial stromal tumors (ESTs). Rearrangements of JAZF1, SUZ12, PHF1, and EPC1 have been reported in endometrial stromal nodules (ESNs), endometrial stromal sarcomas (ESSs), and rarely in undifferentiated endometrial sarcomas (UESs). Detection of JAZF1, SUZ12, EPC1, and PHF1 rearrangement by fluorescence in situ hybridization was performed on tissue microarrays consisting of 94 ESTs of classic and variant morphology (20 ESNs, 43 primary uterine ESSs, 15 metastatic uterine ESSs, 4 primary extrauterine ESSs, 7 primary uterine UESs, and 5 unclassified ESTs), 16 Müllerian adenosarcomas, 2 malignant mixed Müllerian tumors, 2 uterine tumors resembling ovarian sex-cord tumors, 2 highly cellular leiomyomas, 1 leiomyosarcoma, and 7 polypoid endometriosis. Rearrangements were detected in 42 of 78 (54%) uterine ESTs, with JAZF1-SUZ12 fusion found in 50% of ESNs and in 33% of ESSs and JAZF1-PHF1 and EPC1-PHF1 fusions found in 1% and <1% of ESSs, respectively. PHF1 and JAZF1 were rearranged with unknown partners in 8 uterine ESTs. JAZF1-SUZ12 fusion, EPC1-PHF1 fusion, and PHF1 rearrangement were found in 3 extrauterine ESSs, whereas no rearrangements were observed in UESs or in any other non-EST studied. Our data confirm that gene rearrangements are present in more than 50% of uterine ESTs, with JAZF1-SUZ12 fusion being the most common, followed by rare EPC1-PHF1 and JAZF1-PHF1 fusions. The presence of identical gene rearrangements in both uterine and extrauterine ESTs suggests a similar pathogenesis. The presence of detectable gene rearrangements in uterine ESS may predict better patient outcome.     

Medication beliefs and perceived barriers in adolescent renal transplant patients and their parents

Understanding patient beliefs about medications and perceived barriers is important for optimal medical management. Differentiating adolescent views from parents?? perceptions would enhance care by increasing communication about regimens and reducing obstacles. This study explored beliefs about medications and perceived barriers among 40 adolescent kidney transplant patients and their parents. Younger adolescents reported greater concern about medication harmfulness (t(38)?=?2.190, p?<?0.05) and more barriers, particularly for practical problems including forgetfulness, organization, and coordination (t(38)?=?2.049, p?<?0.05). Fathers with a lower education reported their children having greater challenges with medications due to taste and size (t(37)?=?2.933, p?<?0.01). Families with incomes in the low and high levels expressed that their children need more medication reminders (F (2, 35)?=?7.815, p?<?0.005), and adolescents from lower-income families perceived medication to be more harmful (F (2, 36)?=?3.815, p?<?0.05). Adolescents expressed challenges with practical aspects of medication taking, whereas parents were more focused on medications being necessary for their health. Adolescent renal patients experience challenges to medication management that may differ from their parents, findings that can help tailor interventions to improve medication management.     

The cardioprotective effect of uridine and uridine-5'-monophosphate: the role of the mitochondrial ATP-dependent potassium channel

The activity of mitochondrial ATP-dependent potassium channel (mitoKATP) of rat heart and liver mitochondria was shown to decrease during aging. This partially explains the increase of risk of ischemia at a mature age since mitoKATP activation provides cardioprotection. We demonstrated that uridine-5'-diphosphate (UDP) possesses the property to activate mitoKATP. At a concentration of 30 microM, it reactivated mitoKATP in mitochondria, and 5-hydroxydecanoate (5-HD) eliminated this effect. In experimental animals, UDP precursors uridine and uridine-5'-monophosphate (UMP) (both 30 mg/kg, administered intravenously 5 min before coronary occlusion) decreased the myocardium ischemic alteration index (1.9 and 3.5 times, respectively) and the T-wave amplitude within 60 min after occlusion. Both effects were inhibited by Glibenclamide (Glib) and 5-HD. UMP and uridine decreased the number of premature ventricular beats 5.6 and 1.9 times and the duration of ventricular tachycardia 9.4 and 4.1 times, respectively. Glib and 5-HD inhibited the anti-arrhythmic parameters, 5-HD being less effective. Uridine and UMP decreased the duration of fibrillation 10.8 and 3.6 times, respectively, and this effect was not abolished by Glib and 5-HD. Thus, uridine and UMP, which are the precursors of UDP in the cell, possess cardioprotective properties. MitoKATP prevents mainly ischemic injuries and partially rhythm disorders.     

Absence of a classically activated macrophage cytokine signature in peripheral spondylarthritis,including psoriatic arthritis

Objective

Peripheral spondylarthritis (SpA) is characterized by macrophages that express CD163, a marker of alternative activation (M2). The purpose of this study was to assess whether this differential infiltration with macrophage subsets was associated with a different local inflammatory milieu in SpA as compared with rheumatoid arthritis (RA).

Methods

The effect of SpA and RA synovial fluid (SF) on macrophage polarization was tested in vitro on normal peripheral blood monocytes. SF levels of classically activated macrophage (M1)–derived and alternatively activated macrophage (M2)–derived mediators were analyzed by enzyme‐linked immunosorbent assay and multiparameter Luminex bead assay in 47 patients with non‐psoriatic SpA, 55 with RA, and 15 with psoriatic arthritis (PsA). Paired synovial biopsy samples were analyzed histologically.

Results

SF from SpA patients promoted preferential expression of the M2 markers CD163 and CD200R in vitro, even if SF levels of the prototypical M2‐polarizing factors (interleukin‐4 [IL‐4], IL‐13, and IL‐10) were not increased as compared with those in RA SF. Despite a similar degree of overall joint inflammation in SpA and RA, SpA synovitis displayed strongly reduced SF levels of M1‐derived, but not M2‐derived, mediators, such as tumor necrosis factor α (TNFα), IL‐1β, IL‐12p70, and interferon‐γ–inducible protein 10. SF levels of M1‐derived mediators correlated well with peripheral joint inflammation in RA, but neither these mediators nor IL‐1α and IL‐17 did so in SpA. Of interest, the SF cytokine profile in PsA, a more destructive subtype of SpA, was similar to that in non‐psoriatic SpA.

Conclusion

The local inflammatory milieu is clearly different in SpA as compared with RA peripheral arthritis. Synovitis in SpA, including that in PsA, is characterized by a selective decrease in M1‐derived proinflammatory mediators, such as TNFα and IL‐1β.

     

Detection of paroxysmal nocturnal hemoglobinuria clones in patients with myelodysplastic syndromes and related bone marrow diseases, with emphasis on diagnostic pitfalls and caveats

Background

The presence of paroxysmal nocturnal hemoglobinuria clones in the setting of aplastic anemia or myelodysplastic syndrome has been shown to have prognostic and therapeutic implications. However, the status of paroxysmal nocturnal hemoglobinuria clones in various categories of myelodysplastic syndrome and in other bone marrow disorders is not well-studied.

Design and Methods

By using multiparameter flow cytometry immunophenotypic analysis with antibodies specific for four glycosylphosphatidylinositol-anchored proteins (CD55, CD59, CD16, CD66b) and performing an aerolysin lysis confirmatory test in representative cases, we assessed the paroxysmal nocturnal hemoglobinuria-phenotype granulocytes in 110 patients with myelodysplastic syndrome, 15 with myelodysplastic/myeloproliferative disease, 5 with idiopathic myelofibrosis and 6 with acute myeloid leukemia.

Results

Paroxysmal nocturnal hemoglobinuria-phenotype granulocytes were detected in nine patients with low grade myelodysplastic syndrome who showed clinicopathological features of bone marrow failure, similar to aplastic anemia. All paroxysmal nocturnal hemoglobinuria-positive cases demonstrated loss of the four glycosylphosphatidylinositol-anchored proteins, with CD16⁻CD66b⁻ clones being larger than those of CD55⁻CD59⁻ (p<0.05). Altered glycosylphosphatidylinositol-anchored protein expression secondary to granulocytic hypogranulation, immaturity, and/or immunophenotypic abnormalities was present in a substantial number of cases and diagnostically challenging.

Conclusions

These results show that routine screening for paroxysmal nocturnal hemoglobinuria clones in patients with an intrinsic bone marrow disease who show no clinical evidence of hemolysis has an appreciable yield in patients with low grade myelodysplastic syndromes. The recognition of diagnostic caveats and pitfalls associated with the underlying intrinsic bone marrow disease is essential in interpreting paroxysmal nocturnal hemoglobinuria testing correctly. In our experience, the CD16/CD66b antibody combination is superior to CD55/CD59 in screening for subclinical paroxysmal nocturnal hemoglobinuria because it detects a large clone size and is less subject to analytical interference.