Predicting Hospital Survival in Patients Admitted to ICU with Pulmonary Embolism.

OBJECTIVE: The Pulmonary Embolism Severity Index (PESI) and simplified PESI (sPESI) predict mortality for patients with PE. We compared PESI/sPESI to the Acute Physiology and Chronic Health Evaluation IV (APACHE-IV) in predicting mortality in patients with PE admitted to the intensive care unit (ICU). Additionally, we assessed the performance of a novel ICU-sPESI score created by adding three clinical variables associated with acuity of PE presentation (intubation, confusion [altered mental status], use of vasoactive infusions) to sPESI. MATERIALS AND METHODS: Using the eICU Collaborative Research Database from 2014 to 2015, we conducted a large retrospective cohort study of adult patients admitted to the ICU with a primary diagnosis of PE. We calculated APACHE-IV, PESI, sPESI, and ICU-sPESI scores and compared their performance for predicting in-hospital mortality using area under the receiver operating characteristic (AUROC) curve. Score thresholds for >99% negative predictive values (NPV) were calculated for each score. Survival was estimated using the Kaplan-Meier method. RESULTS: We included 1424 PE cases. In-hospital mortality was 6.3% [95% CI: 5.1%-7.6%]. AUROC for APACHE-IV, PESI, and sPESI were 0.870, 0.848, and 0.777, respectively. APACHE-IV and PESI outperformed sPESI (P < 0.01 for both comparisons), while APACHE-IV and PESI demonstrated similar performance (P = 0.322). The ICU-sPESI performance was similar to APACHE-IV and PESI (AUROC = 0.847; AUROC comparison: APACHE-IV vs ICU-sPESI: P = 0.396; PESI vs ICU-sPESI: P = 0.945). Hospital mortality for ICU-sPESI scores 0-2 was 1.1%, and for scores 3, 4, 5, 6, and ≥7 was 8.6%, 11.7%, 29.2%, 37.5%, and 76.9%, respectively. Score thresholds for >99% NPV were ≤48 for APACHE-IV, ≤115 for PESI, and 0 points for sPESI and ICU-sPESI. CONCLUSIONS: By accounting for severity of PE presentation, our newly proposed ICU-sPESI score provided improved PE mortality prediction compared to the original sPESI score and offered excellent discrimination of mortality risk.

Infections after kidney transplantation: A comparison of mTOR-Is and CNIs as basic immunosuppressants. A systematic review and meta-analysis.

BACKGROUND: Side effects of the immunosuppressive therapy after solid organ transplantation are well known. Recently, significant benefits were shown for mTOR-Is with respect to certain viral infections in comparison with CNIs. However, reported total incidences of infections under mTOR-Is vs CNIs are usually not different. This raises the question to additional differences between these immunosuppressants regarding development and incidence of infections. METHODS: The current literature was searched for prospective randomized controlled trials in renal transplantation. There were 954 trials screened of which 19 could be included (9861 pts.). The 1-year incidence of infections, patient and graft survival were assessed in meta-analyses. RESULTS: Meta-analysis on 1-year incidence of infections showed a significant benefit of an mTOR-I based therapy when combined with a CNI vs CNI-based therapy alone (OR 0.76). There was no difference between mTOR-I w/o CNI and CNI therapy (OR 0.97). For pneumonia, a significant disadvantage was seen only for mTOR-I monotherapy compared to CNI's (OR 2.09). The incidence of CMV infections was significantly reduced under mTOR-I therapy (combination with CNI: OR 0.30; mTOR w/o CNI: OR: 0.46). There was no significant difference between mTOR-I and CNI therapy with respect to patient survival (mTOR-I w/o CNI vs CNI: OR 1.22; mTOR-I with CNI vs CNI: OR 0.86). Graft survival was negatively affected by mTOR-I monotherapy (OR 1.52) but not when combined with a CNI (OR 0.97). CONCLUSION: Following renal transplantation the incidence of infections is lower when mTOR-Is are combined with a CNI compared to a standard CNI therapy. Pneumonia occurs more often under mTOR-I w/o CNI.

Diagnostic methods for identifying different Aeromonas species and examining their pathogenicity factors, their correlation to cytotoxicity and adherence to fish mucus.

Aeromonas spp. are ubiquitous in the aquatic environment, acting as facultative or obligate pathogens for fish. Identifying Aeromonas spp. is important for pathogenesis and prognosis in diagnostic cases but can be difficult because of their close relationship. Forty-four already characterized isolates of Aeromonas spp. were analysed by 16S rRNA gene sequencing, by gyrase B sequencing, by analysing their fatty acid profiles, by biochemical reactions and by MALDI-TOF MS. To determine their pathogenicity, cytotoxicity, adhesion to mucus and the expression of 12 virulence factors were tested. The susceptibility of the isolates towards 13 different antibiotics was determined. MALDI-TOF MS was found to be an acceptable identification method for Aeromonas spp. Although the method does not detect all species correctly, it is time-effective and entails relatively low costs and no other methods achieved better results. A high prevalence of virulence-related gene fragments was detected in almost all examined Aeromonas spp., especially in A. hydrophila and A. salmonicida, and most isolates exhibited a cytotoxic effect. Single isolates of A. hydrophila and A. salmonicida showed multiple resistance to antibiotics. These results might indicate the potentially pathogenic capacity of Aeromonas spp., suggesting a risk for aquatic animals and even humans, given their ubiquitous nature.

Comparison of pathogenic and non-pathogenic Enterococcus cecorum strains from different animal species.

BACKGROUND: Enterococcus cecorum (EC) infection currently is one of the most important bacterial diseases of modern broiler chickens but can also affect ducks or other avian species. However, little is known concerning pathogenesis of EC and most studies concentrate on examinations of EC strains from broilers only. The objective of this study was to compare pathogenic and commensal EC strains from different animal species concerning different phenotypic and genotypic traits. RESULTS: Pathogenic and commensal EC strains were not clearly separated from each other in a phylogenetic tree based on partial sequences of the 16S-rRNA-gene and also based on the fatty acid profile determined with gas chromatography. C12:0, C14:0, C15:0, C16:0, C17:0, C18:0, C18:1 w7c, C18:1 w9c and C20:4 w6,9,12,15c were detected as the major fatty acids. None of the 21 pathogenic EC strains was able to utilize mannitol, while 9 of 29 commensal strains were mannitol positive. In a dendrogram based on MALDI-TOF MS data, pathogenic strains were not clearly separated from commensal isolates. However, significant differences concerning the prevalence of several mass peaks were confirmed between the two groups. Two different antisera were produced but none of the serotypes was predominantly found in the pathogenic or commensal EC isolates. Enterococcal virulence factors gelE, esp, asa1, ccf, hyl and efaAfs were only detected in single isolates via PCR. No virulence factor was found significantly more often in the pathogenic isolates. The chicken embryo lethality of the examined EC isolates varied from 0 up to 100%. The mean embryo lethality in the pathogenic EC isolates was 39.7%, which was significantly higher than the lethality of the commensal strains, which was 18.9%. Additionally, five of the commensal isolates showed small colony variant growth, which was never reported for EC before. CONCLUSIONS: Pathogenic and commensal EC isolates from different animal species varied in chicken embryo lethality, in their ability to metabolize mannitol and probably showed divergent mass peak patterns with MALDI-TOF MS. These differences may be explained by a separate evolution of pathogenic EC isolates. Furthermore, different serotypes of EC were demonstrated for the first time.

Mycoplasma gallisepticum modifies the pathogenesis of influenza A virus in the avian tracheal epithelium.

Multiple respiratory infections have a significant impact on health and economy. Pathogenesis of co-infecting viruses and bacteria and their interaction with mucosal surfaces are poorly characterized. In this study we established a co-infection model based on pre-incubation of tracheal organ cultures (TOC) with Mycoplasma (M.) gallisepticum and a subsequent infection with avian influenza virus (AIV). Mycoplasma gallisepticum modified the pathogenesis of AIV as demonstrated in TOC of two different avian species (chickens and turkeys). Co-infection promoted bacterial growth in tracheal epithelium. Depending on the interaction time of M. gallisepticum with the host cells, AIV replication was either promoted or suppressed. M. gallisepticum inhibited the antiviral gene expression and affected AIV attachment to the host cell by desialylation of α-2,3 linked sialic acids. Ultrastructural analysis of co-infected TOC suggests that both pathogens may attach to and possibly infect the same epithelial cell. The obtained results contribute to better understanding of the interaction dynamics between M. gallisepticum and AIV. They highlight the importance of the time interval between infections as well as the biological properties of the involved pathogens as influencing factors in the outcome of respiratory infections.

Prediction of mortality in patients with secondary pulmonary embolism based on primary admission indication: A short communication.

We evaluated the prediction of mortality in patients admitted to the intensive care unit (ICU) who subsequently developed a pulmonary embolism (PE) (i.e., secondary PE) using three PE-specific scores, the Pulmonary Embolism Severity Index (PESI), simplified PESI (sPESI), and modified sPESI (ICU-sPESI) and compared them to the gold standard for the assessment of ICU all-cause mortality, the Acute Physiology and Chronic Health Evaluation-IV (APACHE-IV). All critical care admission indications were grouped into four major categories: post-operative, cardiovascular, infectious (sepsis), and other. The APACHE-IV displayed better discriminative ability to predict in-hospital mortality than the PESI and ICU-sPESI, but these two scores still performed fair for the ICU admissions related to postoperative, cardiovascular, and other admission types. Meanwhile, the sPESI displayed poor predictive performance across all four admission categories. Notably, discriminatory performance for patients with an infection-related admission was consistently low regardless of which score was used.

Validity of mortality risk prediction scores in critically ill patients with secondary pulmonary embolism.

Pulmonary embolism (PE) is a feared complication in the ICU, significantly impacting morbidity and mortality of the patients affected. Herein, we assess the use of the Acute Physiology and Chronic Health Evaluation-IV (APACHE-IV) and PE-specific risk scores to predict mortality among intensive care unit (ICU) patients who developed secondary PE. This retrospective cohort study used information from 208 United States critical care units recorded in the eICU Collaborative Research Database during 2014 and 2015. We calculated APACHE-IV, Pulmonary Embolism Severity Index (PESI), simplified PESI (sPESI), and ICU-sPESI scores and compared their predicting performance using the area under the receiver operating characteristic (AUROC) curve. Of 812 patients included in our study, 150 died (mortality, 18.5% [95% CI, 15.8%-21.1%]). Compared to survivors, non-survivors had higher APACHE-IV (86 vs 52, P<0.001), PESI (170 vs 129, P<0.001), sPESI (2 vs 2, P<0.001), and ICU-sPESI (4 vs 2, P<0.001) scores. AUROCs were 0.790 (APACHE-IV); 0.737 (PESI); 0.726 (ICU-sPESI); and 0.620 (sPESI). APACHE-IV performed significantly better than all 3 PE-specific mortality scores (APACHE-IV vs PESI, P=0.041; APACHE-IV vs sPESI, P=0.001; and APACHE-IV vs ICU-sPESI, P=0.021). Both the PESI and ICU-sPESI outperformed the sPESI (PESI vs sPESI, P=0.001; ICU-sPESI vs sPESI, P<0.001). APACHE-IV score was found to be the best instrument for predicting mortality risk, but PESI and ICU-sPESI scores may be used when APACHE-IV is unavailable. sPESI AUROC suggests absence of sufficient discriminative value to be used as a predictor of mortality in patients with secondary PE.

Description of Riemerella columbipharyngis sp. nov., isolated from the pharynx of healthy domestic pigeons (Columba livia f. domestica), and emended descriptions of the genus Riemerella, Riemerella anatipestifer and Riemerella columbina.

A group of 11 bacterial strains was isolated during microbiological investigations of pharyngeal swabs collected from domestic pigeons (Columba livia f. domestica). Phenotypic properties of the isolates closely resembled those of members of the genus Riemerella within the family Flavobacteriaceae. The genus presently contains two species, Riemerella anatipestifer and Riemerella columbina. The pigeon isolates differed from R. columbina by their lack of pigment production and negative CAMP co-haemolysis reaction. They grew more slowly at 37 °C under microaerobic conditions and showed reduced viability during storage under aerobic conditions at different temperatures, compared with both Riemerella species. Comparisons of protein profiles with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS analysis allowed differentiation between the new pigeon isolates and both R. anatipestifer and R. columbina. Phylogenetic analysis based on 16S rRNA gene and rpoB gene (encoding RNA polymerase beta subunit) sequences supported the affiliation of the 11 strains to a novel species within the genus Riemerella, for which we propose the name Riemerella columbipharyngis sp. nov. The type strain is 8151(T) (=DSM 24015(T) = LMG 26094(T)). Emended descriptions of the genus Riemerella and of its species Riemerella anatipestifer and Riemerella columbina are also presented.

Epidemiological investigations on the role of clinically healthy racing pigeons as a reservoir for avian paramyxovirus-1 and avian influenza virus.

Clinically healthy racing pigeons may harbour notifiable pathogens and serve as an unnoticed reservoir. Thus, 3480 healthy racing pigeons from 172 different lofts were monitored over a period of 2 years for the presence of avian influenza virus (AIV) and avian paramyxovirus-1 (APMV-1). Pharyngeal and cloacal swabs as well as blood samples were collected from juvenile and adult pigeons. Pools of five pharyngeal swabs per loft and age group were initially screened by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). Pharyngeal and cloacal samples from lofts that were positive or suspect in the AIV rRT-PCR or the APMV-1 rRT-PCR were inoculated into embryonated chicken eggs for virus isolation. In addition, sera were examined for antibodies against AIV by enzyme-linked immunosorbent assay. The antibody levels after vaccination against APMV-1 were determined by haemagglutination inhibition assay. Of the investigated lofts, 0.0 to 1.4% were positive by rRT-PCR for APMV-1 and 0.0 to 6.7% for AIV during this 2-year period with a total of four samplings. No sample yielded replicating virus in egg culture. No antibodies against AIV were detected. Haemagglutination inhibition test of vaccinated racing pigeons indicated age-dependent APMV-1 titres. The results suggest that the examined racing pigeons may have had contact with AIV, but virus replication may have been too low to induce detectable circulating antibody levels. Only a low percentage of samples were positive for APMV-1, but two outbreaks were observed in monitored flocks, indicating ongoing circulation of APMV-1 in the racing pigeon population. These observations highlight the relevance of APMV-1 vaccination and indicate the importance of flock immunity.

Evaluation of different diagnostic tools for the detection and identification of Riemerella anatipestifer.

Riemerella anatipestifer (RA) is an important avian pathogen with considerable impact on poultry production worldwide. However, the diagnosis of RA infections may be difficult, mainly due to problems with unequivocal differentiation of RA from other Flavobacteriaceae and a lack of standardized methods and reagents. The aim of the present study was therefore to complement the routine diagnostic strategies for RA by design and evaluation of alternative diagnostic tools. We designed and validated a new RA-specific polymerase chain reaction assay, which proved to be a valuable tool for the identification of RA isolates as well as for rapid and sensitive RA detection directly from diagnostic samples. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry fingerprinting of whole bacterial cells was also demonstrated to identify RA isolates efficiently. Furthermore, this method may also provide opportunities for RA subtyping. In our study, a stable subcluster was formed by the mass spectroscopy profiles of a group of RA isolates originating from turkey flocks in northern Germany, suggesting an epidemiological relationship of these isolates. Serotyping is a further important measure to characterize RA isolates. We tested a set of commercially available anti-RA sera with RA serotype reference strains and field isolates to allow comparison between these sera and reference sera. In summary, this report contributes to the improvement of present microbiological and molecular strategies for the diagnosis of RA infections by providing new tools as well as enhanced knowledge on existing methods.

Epidemiological investigations on the possible risk of distribution of zoonotic bacteria through apparently healthy homing pigeons.

Clinically healthy homing pigeons may serve as an unnoticed reservoir for zoonotic bacteria. Hence, healthy pigeons from 172 different racing pigeon lofts were examined for Salmonella serovars, Campylobacter spp. and Chlamydophila (Chlamydia) psittaci. Two samplings were performed during the racing season in summer (1242 adult and 1164 juvenile pigeons) and two during winter (1074 adult pigeons). Each sampling was accompanied by a questionnaire to identify risk factors for positive lofts. Between 0.9 and 3.7%, 13.1 and 23.7%, and 12.8 and 42.6% of lofts were tested positive by cultural methods or polymerase chain reaction for Salmonella Typhimurium var. Copenhagen, Campylobacter jejuni and C. psittaci, respectively. The detection rate of C. psittaci was twice as high in samples from juvenile pigeons (29.1%) compared with samples from adult pigeons (15.0%, P <0.001). No other influence of age or season was detected. For the first time, pigeon-derived C. jejuni isolates (n=15) were characterized for their ability to invade human enterocytes in vitro. All isolates were invasive with an invasion index between 0.4 and 34.1 (human reference strain: average 11.3). Of 50 C. jejuni isolates tested for antimicrobial susceptibility, 46.0% were resistant to ciprofloxacin. All isolates were sensitive to erythromycin and tetracycline. The analysis of risk factors in association with the infection status of lofts for C. jejuni and C. psittaci suggested that biosecurity measures reduce the risk of infection. This study indicated a zoonotic potential of pigeon-derived C. jejuni. However, clinically healthy homing pigeons pose only a low risk for transmission of the investigated pathogens to humans.

The cathepsin-S/protease-activated receptor-(PAR)-2 axis drives chronic allograft vasculopathy and is a molecular target for therapeutic intervention.

BACKGROUND: Cathepsin S (CatS) and proteinase-activated receptor (PAR)-2 are involved in the remodelling of vascular walls and neointima formation as well as in alloantigen presentation and T-cell priming. Therefore, we hypothesized that CatS/PAR-2 inhibition/deficiency would attenuate chronic allograft vasculopathy. METHODS: Heterotopic aortic murine transplantation was performed from C57BL/6J donors to C57BL/6J recipients (syngeneic control group), Balb/c to C57BL/6J without treatment (allogenic control group), Balb/c to C57BL/6J with twice daily oral CatS inhibitor (allogenic treatment group) and Balb/c to Par2-/- C57BL/6J (allogenic knockout group). The recipients were sacrificed on day 28 and the grafts were harvested for histological analysis and RT-qPCR. RESULTS: After 28 days, mice of the allogenic control group exhibited significant neointima formation and massive CD8 T-cell infiltration into the neointima while the syngeneic control group showed negligible allograft vasculopathy. The mRNA expression level of CatS in allografts was 5-fold of those in syngeneic grafts. Neointima formation and therefore intima/media-ratio were significantly decreased in the treatment and knockout group in comparison to the allogenic control group. Mice in treatment group also displayed significantly fewer CD8 T cells in the neointima compared with allogeneic controls. Additionally, treatment with the CatS inhibitor and PAR2-deficiency decreased mRNA-levels of interleukins and cytokines. CONCLUSION: In conclusion, our data indicate that inhibiting CatS and PAR-2 deficiency led to a marked reduction of neointima formation and associated inflammation in a murine heterotopic model for allograft vasculopathy.

Effect of Sirolimus vs. Everolimus on CMV-Infections after Kidney Transplantation-A Network Meta-Analysis.

(1) Background: Following renal transplantation, infection with cytomegalovirus (CMV) is a common and feared complication. mTOR-inhibitor (mTOR-I) treatment, either alone or in combination with calcineurininhibitors (CNIs), significantly reduces the CMV incidence after organ transplantation. As of now, there is no information on which mTOR-I, sirolimus (SIR) or everolimus (ERL), has a stronger anti-CMV effect. (2) Methods: The current literature was searched for prospective randomized controlled trials in renal transplantation. There were 1164 trials screened, of which 27 could be included (11,655 pts.). We performed a network meta-analysis to analyze the relative risk of different types of mTOR-I treatment on CMV infection 12 months after transplantation compared to CNI treatment. (3) Results: Four different types of mTOR-I treatment were analyzed in network meta-analyses­SIR mono, ERL mono, SIR with CNI, ERL with CNI. The mTOR-I treatment with the strongest anti-CMV effect compared to a regular CNI treatment was ERL in combination with a CNI (relative risk (RR) 0.27, confidence interval (CI) 0.22−0.32, p < 0.0001). The other mTOR-I therapy groups showed a slightly decreased anti-CMV efficacy (SIR monotherapy (mono): RR 0.35, CI 0.22−0.57, p < 0.001; SIR with CNI: RR 0.43, CI 0.29−0.64, p < 0.0001; ERL mono: RR 0.46, CI 0.22−0.93, p = 0.031). (4) Conclusions: The anti-CMV effect of both mTOR-Is (SRL and ERL) is highly effective, irrespective of the combination with other immunosuppressive drugs. Certain differences with respect to the potency against the CMV could be found between SRL and ERL. Data gained from this analysis seem to support that a combination of ERL and CNI has the most potent anti-CMV efficacy.

Pathogenesis of Riemerella anatipestifer in turkeys after experimental mono-infection via respiratory routes or dual infection together with the avian metapneumovirus.

Riemerella anatipestifer (RA) is the causative agent of septicaemic and exudative diseases in a variety of bird species. Despite numerous outbreaks, little is known about the pathogenicity of RA for turkeys. We investigated the development of RA-induced disease in commercial turkey poults following RA inoculation via different respiratory routes. Inoculation by aerosol or injection into the abdominal air sac led to systemic infection and mild gross lesions, including pericarditis, epicarditis and airsacculitis, which were less pronounced compared with field outbreaks. It was speculated, that viral pathogens, such as the avian metapneumovirus (aMPV), may exacerbate RA pathogenesis under field conditions. We inoculated turkey poults with virulent aMPV. Subsequently, aMPV-infected and virus-free birds were exposed 3 to 5 days later to a high dose of RA by aerosol (>10(10) colony-forming units/ml in 8 ml aerosol per 11 or 12 birds) or were inoculated 4 days later with a low RA dose (10(4.9) colony-forming units per bird) via the intranasal route. Intranasal RA inoculation with the low bacterial dose led to a respiratory and systemic RA infection in aMPV-infected birds, while virus-free birds remained RA-negative. Following exposure to a high RA dose by aerosol, aMPV-infected groups showed slightly enhanced incidences of gross lesions and RA re-isolation. The present study clearly confirms that RA is pathogenic for turkeys after experimental inoculation via respiratory routes, which are speculated to be the natural route of infection. However, experimental models in this study did not reproduce the severity of RA-related disease as observed under field conditions, which emphasizes the importance of other contributing factors. aMPV-induced respiratory lesions may serve as a predisposing factor for the establishment of RA infection, since they favour colonization of the bacterium.

Murine Cervical Aortic Transplantation Model using a Modified Non-Suture Cuff Technique.

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. However, only minor improvement in the long-term results of transplanted solid organs could be observed over the past decades. In this context, chronic allograft vasculopathy (CAV) still represents the leading cause of late organ failure in cardiac, renal and pulmonary transplantation. Thus far, the underlying pathogenesis of CAV development remains unclear, explaining why effective treatment strategies are presently missing and emphasizing a need for relevant experimental models in order to study the underlying pathophysiology leading to CAV formation. The following protocol describes a murine heterotopic cervical aortic transplantation model using a modified non-suture cuff technique. In this technique, a segment of the thoracic aorta is interpositioned in the right common carotid artery. With the use of the non-suture cuff technique, an easy to learn and reproducible model can be established, minimizing the possible heterogeneity of sutured vascular micro anastomoses.

Draft Genome Sequence of Riemerella anatipestifer Isolate 17CS0503.

Riemerella anatipestifer is a Gram-negative bacterium belonging to the family Flavobacteriaceae It is primarily associated with acute septicemia in younger birds. The R. anatipestifer isolate 17CS0503 described here was isolated from a Peking duck (Anas platyrhynchos domesticus) in Hannover, Germany, in 1999.

Fatty acid composition of Yersinia ruckeri isolates from aquaculture ponds in northwestern Germany.

Enteric Redmouth Disease (ERM), caused by Yersinia (Y.) ruckeri is one of the most important diseases in salmonid aquaculture. Outbreaks of ERM were controlled by vaccines directed against motile strains of the bacterium, until recently nonmotile vaccine-resistant strains evolved and caused severe outbreaks. Non-motile isolates were found widespread in aquaculture populations in north-western Germany. In the present study, 82 Y. ruckeri isolates were isolated from trout hatcheries in North Rhine Westfalia, Lower Saxony and Hessen and only 20% of them were motile. In order to further characterise the Y. ruckeri isolates from fish aquaculture populations in north-western Germany, the fatty acid compositions of 82 Y. ruckeri field isolates from this area and of the Y. ruckeri reference strain DSM 18506 were analysed by gas chromatography. All Y. ruckeri isolates exhibited 15 major fatty acids, including 12:0, 13:0, 13.957 (equivalent chain length, ECL unknown), 14:0, 14.502 (ECL unknown), 15:0, 16:1omega5c, 16:0, 17:1omega8c, 17:0 CYCLO, 17:0, 16:1 2OH, 18:1omega9c, 18:1omega7c and 18:0. From a dendrogram, all isolates were close to one another, clustering together; while slight differences were detected among the isolates and the reference strain DSM 18506. Compared to their epidemiological and biochemical characteristics, there was no relationship found between the fatty acid profiles, API 20E profiles, motility and geographic distribution. Our results show that the fatty acid composition of Y. ruckeri isolates from north-western Germany is highly homogenous.

Isolation and characterization of atypical Riemerella columbina strains from pigeons and their differentiation from Riemerella anatipestifer.

Riemerella columbina (RC) and Riemerella anatipestifer (RA) belong to the genus Riemerella within the family Flavobacteriaceae. While RA is a well-described pathogen of waterfowl and other avian species, only little is known about RC. Previous work reporting the isolation of RC from internal organs of clinically diseased pigeons suggested a potential pathogenic role in this avian species. In this study we examined pharyngeal swabs collected from pigeons and found RC to be widely distributed also among healthy birds. Further characterization of 81 RC-isolates revealed several atypical strains, which differed from all previously described RC-isolates by the lack of aesculin-hydrolysis activity (17 isolates) or by expression of yellow or orange pigmentation (6 isolates). Sequence analysis of the 16S rRNA and outer membrane protein A (ompA) gene supported the affiliation of these strains to the species RC. Aesculin-hydrolysis negative isolates were found to be biochemically indistinguishable from RA. We demonstrated that bacterial fingerprinting using matrix assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) analysis is useful for the identification and differentiation of RC and RA.

Virulence of Mycoplasma synoviae strains in experimentally infected broiler chickens.

Seven field isolates of German origin and the type strain WVU 1853 of Mycoplasma synoviae (MS) were experimentally investigated for their virulence in mycoplasma-free broiler chickens. Two groups of birds were inoculated at 6 days of age with each isolate, one group into the thoracic air sac and the other group intravenously and all surviving birds were examined at necropsy 17 days post inoculation (pi). Groups of negative control birds received sterile Frey's broth medium by intravenous and intra-air sac inoculation, respectively. Variation in virulence was evaluated on the basis of significant differences in incidence, severity and extend of MS-induced airsacculitis and synovitis as well as isolation rates of MS especially from parenchymous organs. All the strains tested were pathogenic but varied in their virulence for broiler chickens. Based on differences of the virulence, the isolates were classified to the categories: (1.) highly virulent, (2.) virulent, (3.) moderately virulent and (4.) slightly virulent. (1) Strains WVU 1853 and 246-91 induced a systemic disease associated with multiple synovitis and bilateral airsacculitis (2) Strains 93-92 and 151-77 induced bilateral airsacculitis similar to WVU 1853 and 246-91 but rarely a systemic disease after exposure by intra-thoracic airsac inoculation. (3) In comparison, strains 27-79, 76-93 and 513-83 caused less frequently airsacculitis and even if, then only at the side of intra-airsac exposure. (4) Strain 91-93 has been found to differ significantly from all the other isolates in its capacity to produce disease independently from the inoculation route. After intravenous inoculation, findings gave no indications for strains with selective tropism to the epithelial membranes of the lower respiratory tract or to those of the joints, tendon sheaths and bursae. However, the presented data of the experiments suggest that the MS strains tested differ in their potential capacity to invade systemically and produce acute septicaemia.

[Isolation and differentiation of a cytochrome oxidase-negative strain of Ornithobacterium rhinotracheale from turkeys]. / Isolierung und Differenzierung eines Cytochromoxidase-negativen Ornithobacterium-rhinotracheale-Stamms aus Puten.

The present study describes the first isolation and identification of a cytochrome oxidase-negative strain of Ornithobacterium rhinotracheale. This strain was isolated from 19-week-old turkeys with severe respiratory signs and was identified using biochemical, cytochemical and serological test methods. These findings indicate that cytochrome oxidase-negative Ornithobacterium rhinotracheale strains become probably also an important rule as a causative agent.