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.

     

Elevated tryptase levels are associated with greater bone density in a cohort of patients with mastocytosis

BACKGROUND: Mastocytosis is associated with a pathological increase in tissue mast cells. Associated skeletal problems include a decrease in bone density and pathological fractures. METHODS: In order to explore the relationship between bone density and the severity of mastocytosis, 21 patients with mastocytosis who underwent dual-energy X-ray absorptiometry were entered into this study. Correlation coefficients were computed between Z-scores and demographic, clinical and laboratory data. Femoral neck Z-scores correlated with serum tryptase levels when all the patients were considered (p=0.029). RESULTS AND CONCLUSION: Patients with less severe disease had significantly lower values at the L1-L4 spine (p=0.046) and femoral neck (p=0.029) Z-scores compared to patients with more severe disease. Most patients who had low Z-scores (between -1 and -2.5) were under 50 years of age, had less severe disease and had lower serum tryptase levels. A history of gastroesophageal reflux disease and a history of hypotensive episodes correlated with lower L1-L4 spine Z-scores (p<0.05). Thus, patients with less severe disease and lower serum tryptase levels should in particular have their bone density determined with treatment appropriate to the findings.     

Strain differences in allele and expression levels of CD72 on B-lymphocytes from NOD, AKR, NON and C57BL/6 mice

The B-lymphocyte marker CD72 has multiple alleles and serves crucial and nonredundant roles in B-cell development and activation. B-lymphocytes play an important role in development of autoimmune diabetes in NOD mice, therefore we examined the patterns of expression of CD72 and its alloantigens on splenic lymphocytes from 4-week-old NOD/LtJ mice. Comparisons of CD72 expression were made between NOD mice and three non-diabetic strains, NON/LtJ mice, C57BL/6J and AKR/J. Use of allele-specific monoclonal antibodies revealed that the previously uncharacterized NON strain expresses either the a or d allele, whereas NOD and AKR mice were confirmed to express the rare c allele. Flow cytometric analysis revealed differential expression between the strains. Whereas NON, C57BL/6 and AKR mice expressed CD72 on 98, 94 and 92% of their B-lymphocytes (CD19+ cells), the NOD mice only expressed this regulatory marker on 78% of their B-lymphocytes. Furthermore, CD72 expression levels on CD72 positive cells were lower in NOD mice than in other three non-diabetic strains. The presence of the CD72c allele, as well as its low level of expression in NOD mice at 4 weeks of age, may be associated with B-lymphocyte hyper-responsiveness and resistance to activation-induced cell death.     

Progestin-based contraceptive suppresses cellular immune responses in SHIV-infected rhesus macaques

Nine rhesus macaques in groups of three received a single dose of the injectable progestin-based contraceptive Depo-Provera 5 weeks prior to challenge intravaginally with varying doses of a mixture of the pathogenic CXCR4 (X4)-SHIV(SF33A) and CCR5 (R5)-SHIV(SF162P3) isolates. As controls, seven Depo-naive animals were inoculated once with a high-dose of the mixed inoculum. Irrespective of inoculum dose, acute viremia was higher in the Depo-treated than in the Depo-naive animals. Further, genetic complexity of the replicating virus was greater and replication of the X4 virus was favored in dually infected animals treated with Depo-Provera. Analysis of cellular immune responses revealed slower response rates in virus-specific IFN-gamma production to SIV Gag in the Depo-treated macaques. The immunosuppressive effect of Depo-Provera on mounting an antiviral cellular immune response may account for the increase viral burden and diversity, and the predominance of X4 virus replication in SHIV infected macaques that were administered the progestin-based contraceptive.