Characterization of Methicillin-resistant Staphylococcus aureus From Children at Hospital Admission: Experiences From a Hospital in a German Metropolitan Area

BACKGROUND

Since the 1990s, community-associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) are described as emerging independent of health care. CA-MRSA is associated with the colonization and infection of healthy, immunocompetent younger individuals. While skin and soft tissue infections (SSTI) are predominant, life-threatening syndromes can also occur.

METHODS

In this retrospective study, we investigated MRSA stains isolated from community-onset infections and from MRSA screening of children at admission to a tertiary-care hospital in 2012-2018. In total, 102 isolates were subjected to antibiotic susceptibility testing by broth microdilution, spa -typing, multilocus sequence typing, SCC mec typing and virulence/resistance gene detection by polymerase chain reaction.

RESULTS

The majority of isolates originated from community-onset infections (80/102), of these primarily from SSTI (70/80). Additional strains were isolated by MRSA screening (22/102). In total 61.8% of the MRSA carried the gene for the Panton-Valentine leukocidin ( lukPV ). Molecular characterization of isolates revealed various epidemic MRSA clones, circulating in both community and hospital settings. Most prevalent epidemic lineages were isolates of the "European CA-MRSA clone" (CC80-MRSA-IV), the "Bengal Bay clone" (ST772-MRSA-V), or the "USA300 NAE clone" (ST8-MRSA-IVa).

CONCLUSIONS

Our data highlight the importance of CA-MRSA causing SSTI in children. More frequent microbiological and molecular analysis of these strains is important for targeted treatment and can provide valuable data for molecular surveillance of the pathogen.

Alters- und geschlechtsbezogene Verteilung von Zuführung, Ersteinschätzung, Entlassart und Verweildauer in der zentralen Notaufnahme

Einleitung

Jährlich stellen sich bundesweit zahlreiche Patienten in zentralen Notaufnahmen vor. Ziel der vorliegenden Untersuchung war es, alters- und geschlechtsabhängig Zuführung, Ersteinschätzung, Entlassart und Verweildauer an einem universitären Standort zu analysieren.

Material und Methodik

In dieser retrospektiven Studie wurden alle Patientenkontakte der zentralen Notaufnahme des Universitätsklinikums Düsseldorf des Jahres 2019 erfasst und anhand der Prozesskriterien Zuführung, Ersteinschätzung, Entlassart und Verweildauer kategorisiert und deren Verteilung untersucht.

Ergebnisse

Vom 01.01. bis 31.12.2019 wurden insgesamt 43.821 Patientenkontakte erfasst. Das durchschnittliche Alter der Patienten betrug 47 ± 24 Jahre (Median: 47, Min.–Max.: 0–106). Der Anteil weiblicher Patienten betrug 48 %. Ein Alter ≤ 17 Jahren wiesen 10 % der Patienten (♀ vs. ♂: 4 vs. 6 %, p < 0,0001) und ein Alter ≥ 70 Jahre 24 % auf (♀ vs. ♂: 13 vs. 11 %, p < 0,0001). Für beide Geschlechter nahm der Anteil der Triagekategorien „blau“ und „grün“ über die aufsteigenden Altersgruppen stetig ab. Ab der Altersgruppe der 50- bis 59-Jährigen lag für beide Geschlechter führend eine höhere Dringlichkeit („gelb“ bis „rot“) vor. Während im Alter ≤ 17 Jahren mit 84–90 % vorwiegend eine ambulante Behandlung erfolgte, reduzierte sich dieser Anteil über die weiteren Altersgruppen bis auf 22 % bei Männern und 28 % bei Frauen in der Altersgruppe der ≥ 90-Jährigen. Für die drei Entlassarten „ambulant“, „prästationär“ und „stationär“ stieg die Verweildauer bei beiden Geschlechtern mit dem Alter kontinuierlich an.

Schlussfolgerung

Es finden sich deutliche und vor allem altersabhängige Unterschiede in den Prozesskriterien Zuführung, Ersteinschätzung, Entlassart und Verweildauer. Rund 15 % der Patienten sind kritisch krank oder verletzt („orange“ und „rot“). Mit steigendem Alter nimmt der Anteil dieser Triagekategorien zu. Bei rund 30 % der Patienten besteht eine stationäre Aufnahmeindikation, entsprechende Bettenkapazitäten müssen täglich eingeplant werden.

Conditional expression of N-myc in human neuroblastoma cells increases expression of alpha-prothymosin and ornithine decarboxylase and accelerates progression into S-phase early after mitogenic stimulation of quiescent cells

To elucidate the contribution of the N-Myc protein to neuroblastomas we have used a synthetic inducible expression system on the basis of the tetracycline repressor of E coli to reversibly express N-myc in a human neuroblastoma cell line in which expression of endogenous N-myc is barely detectable. Like the c-Myc protein, N-Myc up-regulates the expression of both alpha-prothymosin and ornithine decarboxylase. Induction of N-myc increases both the rate of DNA-synthesis and the proliferation rate, and shortens the G1 phase of the cell cycle. A comparison of cell populations in which the presence of N-Myc protein was restricted to different parts of G(zero)/G1 revealed that N-Myc is rate-limiting for cell cycle progression during the first 5 h after serum stimulation of quiescent cells providing direct evidence that Myc-proteins act early after mitogenic stimulation of quiescent cells.

The DDX1 gene maps within 400 kbp 5' to MYCN and is frequently coamplified in human neuroblastoma

Human neuroblastoma cells frequently show amplification of the oncogene MYCN, which maps to 2p24. Previous studies have localized the DEAD box motif gene DDX1 to the same chromosome band and demonstrated coamplification of DDX1 and MYCN in two retinoblastoma cell lines. Recently, a high frequency of coamplification of DDX1 and MYCN has been shown in human neuroblastoma cells. We have determined the physical distance between the two genes by pulsed field gel electrophoresis in normal tissue and have found that DDX1 maps to a position at a maximum distance of 400 kbp 5' to MYCN. Two neuroblastoma cell lines with coamplification of DDX1/MYCN showed a similar topographic relationship of the two genes. In contrast, in two cell lines with high copy number, the DDX1 gene was not present in all amplified units recognized by MYCN and had changed its position in the amplified DNA relative to MYCN from 5' to 3', presumably by rearrangement during the amplification process. Our data show that the high frequency of DDX1 coamplification is due to its close physical distance to MYCN. Although amplification has resulted in an elevated expression of DDX1 the significance of overexpression for neuroblastoma remains unclear.

Vascularization of primary central nervous system tumors: detection with contrast-enhanced transcranial color-coded real-time sonography

PURPOSE

To study the potential of contrast material-enhanced transcranial color-coded real-time sonography (TCCS) in detection of primary intracranial tumor vascularization.

MATERIALS AND METHODS

Primary central nervous system (CNS) tumors in 28 patients were examined with TCCS before and during administration of a transpulmonary, stable, galactose, microparticle-based ultrasound (US) contrast agent. All patients underwent cranial computed tomography and magnetic resonance imaging; nine patients also underwent intraarterial digital subtraction angiography.

RESULTS

All lesions were hyperechoic on B-mode US scans except one grade 2 astrocytoma. The location and extent of hyperechoic lesions correlated well with findings on CT scans and MR images. After injection of contrast material, color Doppler flow signals were seen in nine of 14 low-grade lesions and 14 of 14 high-grade lesions. High-grade malignant tumors always had atypical arterial and venous Doppler spectra with irregular distribution of Doppler shift and signal intensities; these atypical flow patterns were also detected in some low-grade tumors.

CONCLUSION

In addition to depiction of primary CNS tumors in B-mode, contrast-enhanced TCCS enables evaluation of vascularization associated with tumor parenchyma.

Activation of gene transcription by the amino terminus of the N-Myc protein does not require association with the protein encoded by the retinoblastoma suppressor gene RB1

N-Myc encodes a nuclear phosphoprotein that contains a basic region (BR), a helix-loop-helix (HLH) and a leucine zipper (Zip). These motifs are hallmarks of certain transcription factors. In pursuit of the question if N-Myc can activate transcription, we have employed an experimental model involving the yeast transcription factor Gal4. We have first generated fusion proteins containing the Gal4 DNA-binding domain joined to portions of N-Myc. Subsequently we have analysed if chimeric proteins can transactivate the transcription of a reporter under the control of Gal4 binding sites. Here we show that the amino terminal portion of N-Myc activates transcription. Activation maps to a domain highly conserved among Myc-proteins and to other non-conserved sequences, suggesting functional redundancy. Previous studies had documented in vitro association of the RB1 protein with N-Myc (Rustig et al., 1991). We here confirm this observation and identify the region encompassing the transactivation domain as responsible for RB1 binding. Analyses of N-Myc transactivation in retinoblastoma cell line WERI lacking a function RB1 protein gave results similar to those with cell lines having an intact RB1 protein, showing that RB1 protein is not required for transactivation by N-Myc. The present findings leave open the question if deregulated expression of N-Myc contributes to tumorigenesis by transcriptional activation of as yet unidentified target genes or by functionally inactivating the protein encoded by the tumor suppressor gene RB1, or by a combination of both.

The N-Myc oncoprotein is associated in vivo with the phosphoprotein Max(p20/22) in human neuroblastoma cells

Proteins encoded by the proto-oncogenes c-myc, L-myc, and N-myc contain at their carboxy-terminus a tripartite segment comprising a basic DNA binding region (BR), a helix-loop-helix (HLH) and a leucine zipper motif (Zip), that are believed to be involved in DNA binding and protein-protein interaction. The N-Myc oncoprotein is overexpressed in certain human tumors that share neuroectodermal features due to amplification of the N-myc gene. Using a monoclonal antibody directed against an N-terminal epitope of the N-Myc protein in immunoprecipitations performed with extracts of neuroblastoma cells, two nuclear phosphoprotein, p20/22, forming a hetero-oligomeric complex with N-Myc are identified. Both proteins are phosphorylated by casein kinase II in vitro. By partial proteolytic maps we show that p20 and p22 are structurally related to each other and that p20 is identical with Max, a recently described in vitro binding partner of myc proteins. Time course experiments show the presence of the complex in cellular extracts immunoprecipitated within a 5 min interval after the preparation of the cell extract. While the expression of N-myc is restricted, expression of both Max(p20/22) and the murine homolog Myn(p20/22) was observed in cells of diverse human and murine embryonal lineages as detected by heterologous complex formation. By introduction of expression vectors containing the wild type N-myc gene or N-myc genes with in frame deletions or point mutations into recipient cells and subsequent immunoprecipitation of the resulting N-Myc proteins we show that the HLH-Zip region is essential to the formation of the N-Myc-p20/22 complex.

[Clinical comparative study of local anesthetics. Random double blind study with four commercial preparations]

In a randomized double blind study effects and tolerability of the local anesthetics Prilocaine 3% with Felypressin, Articaine 4% with Epinephrine 1/200,000 and 1/100,000, and Lidocaine 2% with Epinephrine 1/100,000 were tested. There was no significant difference between the four agents as far as effect on blood pressure, pulse, and tissue rehabilitation are concerned. Prilocaine can be used for extractions and surgical tooth removal. It can not be recommended for apicoectomy or implantation. The better results of Articaine 4% compared to Lidocaine 2% were statistically not significant.

Multiple interactions between nuclear proteins of Zea mays and the promoter of the Shrunken gene

Nuclear proteins were extracted from isolated nuclei of immature maize kernels. The promoter region (1.5 kb) of the Shrunken gene, which is highly transcribed in the developing endosperm of the kernel, was scanned for protein-DNA interactions. Several promoter fragments showed protein-DNA complex formation in gel retardation experiments. Two different nucleo-protein complexes (MNP1 and MNP2) have been distinguished in competition and DNase I footprinting experiments. Both nuclear DNA-binding activities are able to recognize multiple sites distributed over a 1.5 kb upstream region of the Shrunken gene. Some of the binding sites established in the in vitro reconstitution experiments are located near to DNase I hypersensitive sites found in the promoter of the Shrunken gene (Frommer and Starlinger 1988).

[Severe hereditary protein C deficiency in a newborn infant with fulminant purpura--successful treatment with phenprocoumon]

A newborn baby was born with scrotal hematoma and a diagnosis of testicular torsion was made. This diagnosis proved false, when the hematoma was resorbed after a few days and other hematomas developed instead (abdomen, elbow, foot, scalp). A total of nine hemorrhagic episodes were observed, most of them occurring on the scalp. All lesions were sharply delineated, started with red to purple discoloration and then turned to bluish-black indicating gangrene. Histology revealed extensive bleeding into the corium, fibrin thrombi within the capillaries, and complement and IgG in the small arterial walls. Each bleeding was associated with hypofibrinogenemia and thrombocytopenia. A diagnosis of hereditary protein C deficiency was made. Blood levels were consistent with heterozygosity of both the parents and homozygosity of the child. Bleedings were controlled by Cohn fraction I and heparin. It was impossible, however, to prevent further hemorrhage by continuous i.v. heparin. In addition aprotinin, epsilon-aminocaproic acid, AT III, and prednisone were ineffective. Continuous remission finally could be sustained with oral phenprocoumon.

Hereditary hypofibrinogenemia with fibrinogen storage in the liver

A family with hereditary autosomal dominant hypofibrinogenemia is described. The outstanding feature is massive deposition of fibrinogen/fibrin within hepatocytes, faintly visible in routine microscopic sections, but clearly demonstrable by immunohistologic techniques. Circulating fibrinogen shows normal electrophoretic mobility of A alpha-, B beta-, and gamma-chains. We assume that the hereditary defect in this family interferes with fibrinogen release from hepatocytes. Clinically there are fluctuating slight elevations of serum transaminase levels. Hemostasis and wound healing are undisturbed.

[Creatine kinase isoenzymes: idiopathic occurrence of creatine kinase BB activities in patient serum (author's transl)]

By differentiation of creatine kinase isoenzyme activities in sera using immunological methods the published data about occurrence of creatine kinase BB activities in patients with different diseases or after surgical treatment, respectively, cannot be verified in general. With a frequency in the order of magnitude of 1 : 1000 in the serum of old patients (age 57 to 85 years with one exception), however, creatine kinase BB activities can be measured. The range of activities is 15 to 234 U/1, or 19 to 94% of total creatine kinase activities, respectively. At the present time there is no possibility to correlate this phenomenon to any specific disease. These cases are detected by abnormally high results of CK-MB activity measurements with the immunoinhibition test (range 60 to 202% of total creatine kinase activities) which lead to a repeated analysis using immunoprecipitation. The results of all CK-BB patients investigated till now are presented and discussed.

[Elaboration of a method for the quantitative determination of proetins by laser nephelometry in the clinical routine laboratory (author's transl)]

The reaction conditions for the quantitative determination of IgC, IgA and IgM in the laser nephelometer were investigated. An easy working scheme was devised. The method was compared with radial immunodiffusion, and it was statistically evaluated.