Transcription Regulator YgeK Affects the Virulence of Avian Pathogenic Escherichia coli

Avian pathogenic Escherichia coli (APEC) is the responsible pathogen for colibacillosis in poultry, and is a potential gene source for human extraintestinal pathogenic Escherichia coli. Escherichia coli type III secretion system 2 (ETT2) is widely distributed in human and animal ExPEC isolates, and is crucial for the virulence of ExPEC. Transcriptional regulator YgeK, located in the ETT2 gene cluster, was identified as an important regulator of gene expression in enterohemorrhagic E. coli (EHEC). However, the role of YgeK in APEC has not been reported. In this study, we performed amino acid alignment analysis of YgeK among different E. coli strains and generated ygeK mutant strain AE81ΔygeK from clinical APEC strain AE81. Flagellar formation, bacterial motility, serum sensitivity, adhesion, and virulence were all significantly reduced following the inactivation of YgeK in APEC. Then, we performed transcriptome sequencing to analyze the functional pathways involved in the biological processes. Results suggested that ETT2 transcriptional regulator YgeK plays a crucial role in APEC virulence. These findings thus contribute to our understanding of the function of the ETT2 cluster, and clarify the pathogenic mechanism of APEC.

CT findings of COVID-19 pneumonia in ICU-patients

Background: In December 2019, a cluster of unknown etiology pneumonia cases occurred in Wuhan, China leading to identification of the responsible pathogen as SARS-coV-2. Since then, the coronavirus disease 2019 (COVID-19) has spread to the entire world. Computed Tomography (CT) is frequently used to assess severity and complications of COVID-19 pneumonia. The purpose of this study is to compare the CT patterns and clinical characteristics in intensive care unit (ICU) and non-ICU patients with COVID-19 pneumonia.Design and Methods: This retrospective study included 218 consecutive patients (136 males; 82 females; mean age 63±15 years) with laboratory-confirmed SARS-coV-2. Patients were categorized in two different groups: (a) ICU patients and (b) non-ICU inpatients. We assessed the type and extent of pulmonary opacities on chest CT exams and recorded the information on comorbidities and laboratory values for all patients.Results: Of the 218 patients, 23 (20 males: 3 females; mean age 60 years) required ICU admission, 195 (118 males: 77 females, mean age 64 years) were admitted to a clinical ward. Compared with non-ICU patients, ICU patients were predominantly males (60% versus 83% p=0.03), had more comorbidities, a positive CRP (p=0.04) and higher LDH values (p=0.008). ICU patients’ chest CT demonstrated higher incidence of consolidation (p=0.03), mixed lesions (p=0.01), bilateral opacities (p<0.01) and overall greater lung involvement by consolidation (p=0.02) and GGO (p=0.001).Conclusions: CT imaging features of ICU patients affected by COVID-19 are significantly different compared with non-ICU patients. Identification of CT features could assist in a stratification of the disease severity and supportive treatment.

Cerebrovascular complications in patients with SARS-CoV-2 infection: Case series

Background: Italy is one of the most affected countries by the Coronavirus disease 2019 (COVID-19). The responsible pathogen is named Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). The clinical spectrum ranges from asymptomatic infection to severe pneumonia leading to intensive care unit admission. Evidence of cerebrovascular complications associated with SARS-CoV-2 is limited. We herein report 6 patients who developed acute stroke during COVID-19 infection. Methods: Retrospective case series of patients diagnosed with COVID-19 using reverse-transcriptase–polymerase-chain-reaction (RT-PCR) on nasopharyngeal swabs, who developed clinical and neuroimaging evidence of acute stroke during SARS-CoV-2 infection.Results: Six patients were identified (5 men); median age was 69 years (range: 57-82). Stroke subtypes were ischemic (4, 67%) and hemorrhagic (2, 33%). All patients but 1 had pre-existing vascular risk factors. One patient developed encephalopathy prior to stroke, characterized by focal seizures and behavioral abnormalities. COVID-19-related pneumonia was severe (i.e. requiring critical care support) in 5/6 cases (83%). Liver enzyme alteration and lactate dehydrogenase (LDH) elevation was registered in all cases. Four patients (67%) manifested acute kidney failure prior to stroke. Four patients (67%) had abnormal coagulation tests. Outcome was poor in the majority of the patients: 4 died (67%), 1 is still in coma (20%) and the remaining 1 remains severely neurologically affected (mRS: 4).Conclusions: Acute stroke can complicate the course of COVI-19 infection. In our series, stroke developed mostly in patients with severe pneumonia and multi organ failure, liver enzymes and LDH were markedly increased in all cases, and the outcome was poor.

Submandibular lymphadenitis due to Mycobacterium malmoense: first reported case from Greece

An 8-year-old girl with subacute submandibular lymphadenitis and no other complaints is described. After failure of parenteral antistaphylococcal therapy, she underwent incision and drainage of the involved lymph node. The responsible pathogen was identified as Mycobacterium malmoense by GenoType CM assay and sequencing of the 16S ribosomalRNA (rRNA) gene. The patient remains healthy, 11 months after surgery, even though it took approximately 4 months for the surgical incision to heal completely. While M. malmoense is a relatively common cause of non-tuberculous mycobacteria (NTM) lymphadenitis in Northern Europe, this is the first reported case from Greece. We conclude that in a young child with lymphadenitis without systemic symptoms, the microbiology laboratory should be notified in advance in order to extend the duration of mycobacterial cultures. Application of molecular methods will increase the number of reported cases of rare NTM in the future.

Leptospirosis Seroconversion Surveillance Among US Marines Assigned to Japan, 2011–2015

Introduction: Leptospirosis is a global zoonotic disease spread through contact with contaminated water/soil. The US soldiers at the military bases in these countries are extremely vulnerable, as most of them are immunologically naïve to the responsible pathogen. No recent sero-epidemiological data of leptospirosis among US Marines stationed in Japan were available. Materials and Methods: In this study, we analyzed the presence of leptospirosis in US Marines stationed in Japan. One thousand posttour sera samples were analyzed by enzyme-linked immunosorbent assay for Leptospira-specific Immunoglobulin G. Results: Among these 1,000 posttour samples, 85 of them were positive and corresponding pretour samples were analyzed by enzyme-linked immunosorbent assay also. Seroconversion occurred for 35 (3.5%) Marines during their assignment to Japan. These results also indicate that 50 Marine personnels were exposed to leptospires before their assignment to Japan, perhaps because of previous exposure to leptospires at home. Conclusion: The 5% rate of seroconversion in 2013 and 2014 suggests that leptospirosis is a potential threat for Marines in the endemic region in Japan.

Dual RNA-seq provides insight into the biology of the neglected intracellular human pathogen Orientia tsutsugamushi

SummaryEmerging and neglected diseases pose challenges as their biology is frequently poorly understood, and genetic tools often do not exist to manipulate the responsible pathogen. Organism agnostic sequencing technologies offer a promising approach to understand the molecular processes underlying these diseases. Here we apply dual RNA-seq to Orientia tsutsugamushi (Ot), an obligate intracellular bacterium and the causative agent of the vector-borne human disease scrub typhus. Half the Ot genome is composed of repetitive DNA, and there is minimal collinearity in gene order between strains. Integrating RNA-seq, comparative genomics, proteomics, and machine learning, we investigated the transcriptional architecture of Ot, including operon structure and non-coding RNAs, and found evidence for wide-spread post-transcriptional antisense regulation. We compared the host response to two clinical isolates and identified distinct immune response networks that are up-regulated in response to each strain, leading to predictions of relative virulence which were confirmed in a mouse infection model. Thus, dual RNA-seq can provide insight into the biology and host-pathogen interactions of a poorly characterized and genetically intractable organism such as Ot.

A case of Lemierre-like Syndrome: internal jugular vein thrombosis secondary to Staphylococcus aureus sternoclavicular joint septic arthritis

Lemierre syndrome is the internal jugular vein (IJV) suppurative thrombophlebitis, usually secondary to oropharyngeal infection. Staphylococcus aureus is an emerging responsible pathogen. We report a unique case of IJV thrombosis secondary to methicillin-susceptible S. aureus sternoclavicular joint septic arthritis. We review the existing literature on Lemierre syndrome: its various manifestations, causative pathogens, treatment and management.

Phytophthora palmivora: A New Pathogen of Olive Trees in Morocco

In spring of 2012, olive-trees with crown dieback, root rot and defoliation were observed in two years old olive tree in commercial plantations of tree nurseries in Sidi Taibi and in twenty to fifty years old field trees in Souk El Arbaa olive crops in Northwest of Morocco (Gharb area). The objective of this study was to isolate the responsible pathogen of the observed symptoms to the olive trees, to demonstrate its pathogenicity and fulfill the Koch´s postulate. Phytophthora palmivora was consistently isolated from roots (56%) and stems (73.6%) of the young olive trees and 85% from stems of field trees. Koch’s postulate was completed using two isolates of Phytophthora palmivora on 2-year old plants of Dahbia and Haouzia varieties grafted onto wild olive-trees. The affected branches percentages (Pab%) of the inoculated olive plants with the isolate 1 were higher (81.8% for Dahbia and 68% for Haouzia) than those what were inoculated with the isolate 2 (43% for Dahbia and 32% for Haouzia). The reisolation percentages (Pr%) of isolate 1 (84%) and isolate 2 (76%) in the roots of Dahbia variety were higher than isolate 1 (48%) and isolate 2 (55%) in roots of Haouzia variety. The reisolation percentage of isolate 1 in the stem of Dahbia (64%) was higher than that in the stem of Haouzia (41.33%). No significant difference was observed between the Reisolation percentages of isolate 2 in stem of Dahbia olive plants (38%) and in stem of Haouzia olive plants (33%). The pathogenicity of P. palmivora was demonstrated in the olive plants and this was the first report of this pathogen in Moroccan olive trees.

Laboratory Diagnosis of Infections in Cancer Patients: Challenges and Opportunities

Infections remain a significant cause of morbidity and mortality in cancer patients. The differential diagnosis for these patients is often wide, and the timely selection of the right clinical tests can have a significant impact on their survival. However, laboratory findings with current methodologies are often negative, challenging clinicians and laboratorians to continue the search for the responsible pathogen. Novel methodologies are providing increased sensitivity and rapid turnaround time to results but also challenging our interpretation of what is a clinically significant pathogen in cancer patients. This minireview provides an overview of the most common infections in cancer patients and discusses some of the challenges and opportunities for the clinical microbiologist supporting the care of cancer patients.