First Report of Bacterial Spot of Peony Caused by a Xanthomonas sp. in the United States

In early May 2008 and 2009, peony samples (Paeonia spp.) with symptoms of leaf spot and blight were submitted to the Virginia Tech Plant Disease Clinic. The 2008 peony was an unknown cultivar from a northern Virginia landscape. The three cultivars (Dr. Alexander Fleming, Felix Crousse, and Karl Rosenfield) submitted in 2009 were from a commercial nursery in southwestern Virginia that was reporting leaf spot progressing to severe blight, which rendered plants unsalable, on 75% of a 1,219 m² block during a 10-day period of heavy rainfall. Bacterial streaming from spots was observed. On the basis of phenotypic and biochemical tests, the isolates were determined to be xanthomonads. Two isolates (one recovered from the 2008 sample and one from the 2009 sample) were used in the following work. Isolates were characterized by multilocus sequencing (MLST) (4). PCR reactions were prepared and cycled using 2X ImmoMix (Bioline, Tauton, MA) according to manufacturer's recommendations with an annealing temperature of 58°C. Template DNA was added by touching a single colony with a 20-μl pipette tip and placing the tip into the reaction mix for 1 min. Four bands of the expected size were visualized on an electrophoresis gel and cleaned products were sequenced in forward and reverse directions at the University of Chicago, Cancer Research Center DNA Sequencing Facility. Corresponding gene fragments of each isolate were identical. A consensus sequence (PAMDB Isolate ID No. 936) for each of the four gene fragments was constructed and compared with sequences in NCBI ( http://www.ncbi.nlm.nih.gov/nuccore/ ) and PAMDB ( http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl ) (1) databases using Blastn (2). No perfect match was found. Genetic distances between the peony isolates and all strains in PAMDB were determined by MegAlign (Lasergene; DNAStar, Madison, WI). The Xanthomonas strain most similar to the isolates recovered from the peony samples was Xanthomonas hortorum pv. hederae ICMP 1661 with a genetic distance of 0.023; this strongly suggests that the peony isolates belong to X. hortorum. For Koch's postulates, six surface-disinfested young leaflets from Paeonia lactiflora 'Karl Rosenfield' were inoculated by forcefully spraying a phosphate-buffered saline suspension of each bacterial isolate (~4.3 × 10⁹ CFU/ml) into the underside of the leaf until leaf tissue appeared water soaked. Controls were inoculated similarly with phosphate-buffered saline solution. Moist chambers with inoculated leaves were incubated at ambient temperature under two 48W fluorescent grow lights with 12 h of light and dark. Circular spots were observed on leaves inoculated with the 2009 and 2008 isolates in 18 and 20 days, respectively. No symptoms were observed on controls. Bacterial streaming from leaf spots was observed by phase-contrast microscopy; bacteria were isolated and confirmed to be identical to the original isolates by the methods described above. To our knowledge, this is the first report of a Xanthomonas sp. causing leaf spot and blight on peony. Although bacterial blight of peony has been attributed to a xanthomonad in recent years, the pathogen had not been further characterized (3). References: (1) N. F. Almeida et al. Phytopathology 100:208, 2010. (2) D. J. Altschul et al. J. Mol. Biol. 215:403, 1990. (3) M. L. Gleason et al. Diseases of Herbaceous Perennials. The American Phytopathological Society, St. Paul, MN. 2009. (4) J. M. Young et al. Syst. Appl. Microbiol. 31:366, 2008.

Patient safety on the otolaryngology service: the role of an established rapid response system

OBJECTIVE

To study the medical emergencies occurring on a tertiary otolaryngology service identified using a rapid response system (RRS).

DESIGN

Retrospective chart review of RRS activations during 21 months.

SETTING

Specialised otolaryngology care unit within the University of Pittsburgh Medical Center Presbyterian/Montefiore Hospital, a tertiary, academic, teaching hospital in the USA.

INTERVENTION(S)

None.

RESULTS

1171 unit admissions. Unit mortality was 5.1/1000 admissions. 53 patients were involved in 67 RRS activations (4/53 deaths). 32 of 67 events were due to respiratory derangements, most commonly pneumonia. 18 of 67 events were due to cardiovascular abnormalities, most commonly hypertension and myocardial infarction. 11 of 67 events were secondary to mental status changes, several of which were related to adverse drug events. 6 of 67 events were secondary to acute bleeding. 23 of 67 events occurred within 24 h of patient transfer/admission, 14 of those after operations. RRS activation was a marker for in-hospital death (RR 42.2, 95% CI 7.9 to 225.2) compared with that in patients not activating the RRS.

CONCLUSIONS

Although otolaryngology care units attempt to prevent adverse events, emergencies still occur. RRSs identify deteriorating otolaryngology patients who are at increased risk for mortality. RRSs are an efficient mechanism of intervention during a medical emergency. RRSs provide a convenient method of identifying medical/system errors and educational opportunities.

Anatomic communications between the three retroperitoneal spaces: determination by CT-guided injections of contrast material in cadavers

OBJECTIVE

A variety of retroperitoneal diseases such as pancreatitis, infection, and trauma may cause fluid collections in the three major retroperitoneal spaces. The purpose of our study was to elucidate flow patterns of fluid between the various compartments to assist the clinical-radiologic assessment and treatment of various retroperitoneal diseases.

MATERIALS AND METHODS

In eight cadavers, CT guidance was used to selectively inject 35-1000 ml of contrast medium by hand or power injector into five perirenal, two posterior pararenal, and two anterior pararenal spaces. After the injections, CT of the entire abdomen and pelvis was done with 10-mm-thick sections at intervals of 10-40 mm. All images were reviewed in detail by a group of experienced body imagers to assess the pathways of flow of contrast material between the three major retroperitoneal spaces.

RESULTS

The caudal cone of perirenal fascia was uniformly patent. A narrow channel connected the two perirenal spaces in the midline; the posterior border of this channel abutted the anterior margins of the abdominal aorta and the inferior vena cava. The perirenal, anterior pararenal, and posterior pararenal spaces all communicated with the infrarenal space, which in turn connected with the extraperitoneal spaces in the pelvis. When large quantities of contrast medium are injected in the perirenal or pararenal spaces and the infrarenal space is filled, the infrarenal space may then serve as a conduit across the midline of the abdomen. The anterior pararenal space crossed the midline and had a distinct retrorenal extension but no intraperitoneal connection. The slender posterior pararenal space had an anterolateral extension en route to the prevesical space.

CONCLUSION

Our findings show pathways and extensions of the perirenal, anterior pararenal, and posterior pararenal spaces that should be considered when assessing a variety of retroperitoneal diseases. Perinephric collections, such as hematomas and urinomas, have at least a potential conduit across the midline or into the pelvis. Our study explains how blood from a ruptured abdominal aortic aneurysm may enter either perinephric space. Anterior pararenal processes, such as pancreatitis or appendicitis, can extend into the pelvis or cross the midline, and posterior pararenal blood from trauma can also flow into the pelvis.

In vitro translation of messenger RNA in a rabbit reticulocyte lysate cell-free system

The identification of specific messenger RNA molecules and the characterization of the proteins encoded by them, has been greatly assisted by the development of in vitro translation systems. These cell-free extracts comprise the cellular components necessary for protein synthesis, i.e., ribosomes, tRNA, rRNA, amino acids, initiation, elongation and termination factors, and the energy-generating system (1). Heterologous mRNAs are faithfully and efficiently translated in extracts of HeLa cells (2), Krebs II ascites tumor cells (2), mouse L cells (2), rat and mouse liver cells (3), Chinese hamster ovary (CHO) cells (2), and rabbit reticulocyte lysates (2,4), in addition to those of rye embryo (5) and wheat germ (6). Translation in cell-free systems is simpler and more rapid (60 min vs 24 h) than the in vivo translation system using Xenopus oocytes.