Pathogenic Microbiology Commons^™

Pandemic Vibrio Cholerae Shuts Down Site-Specific Recombination To Retain An Interbacterial Defence Mechanism, Francis J. Santoriello, Lina Michel, Daniel Unterweger, Stefan Pukatzki

Publications and Research

Vibrio cholerae is an aquatic microbe that can be divided into three subtypes: harmless environmental strains, localised pathogenic strains, and pandemic strains causing global cholera outbreaks. Each type has a contact-dependent type VI secretion system (T6SS) that kills neighbouring competitors by translocating unique toxic effector proteins. Pandemic isolates possess identical effectors, indicating that T6SS effectors may affect pandemicity. Here, we show that one of the T6SS gene clusters (Aux3) exists in two states: a mobile, prophage-like element in a small subset of environmental strains, and a truncated Aux3 unique to and conserved in pandemic isolates. Environmental Aux3 can be readily …

Aspergillus Niger Decreases Bioavailability Of Arsenic(V) Via Biotransformation Of Manganese Oxide Into Biogenic Oxalate Minerals, Bence Farkas, Marek Kolenčík, Miroslav Hain, Edmund Dobročka, Gabriela Kratošová, Marek Bujdoš, Huan Feng, Yang Deng, Qian Yu, Ramakanth Illa, B. Ratna Sunil, Hyunjung Kim, Peter Matúš, Martin Urík

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The aim of this work was to evaluate the transformation of manganese oxide (hausmannite) by microscopic filamentous fungus Aspergillus niger and the effects of the transformation on mobility and bioavailability of arsenic. Our results showed that the A. niger strain CBS 140837 greatly affected the stability of hausmannite and induced its transformation into biogenic crystals of manganese oxalates—falottaite and lindbergite. The transformation was enabled by fungal acidolysis of hausmannite and subsequent release of manganese ions into the culture medium. While almost 45% of manganese was bioextracted, the arsenic content in manganese precipitates increased throughout the 25-day static cultivation of fungus. …

Carbapenem-Resistant Enterobacteriaceae (Cre): Epidemiology, Duration Of Carriage, And Progression To Infection In A Large Healthcare System In Miami, Fl, Adriana Jimenez

FIU Electronic Theses and Dissertations

Carbapenem-resistant Enterobacteriaceae (CRE) are multidrug-resistant organisms (MDRO) considered by the CDC as an urgent public health threat that is spreading globally. Little is known about the epidemiology of CRE in Miami, FL. The purpose of this dissertation was to 1) Evaluate trends in the epidemiology of CRE among patients admitted to the acute care facilities of the largest healthcare system in Miami, FL between 2012 and 2016, 2) Identify factors associated with progressing to infection among patients colonized with carbapenemase-producing Enterobacteriaceae (CPE), and 3) Determine the duration of CPE carriage and factors associated with long-term carriage in our cohort.

A …

Investigating Microbial And Host Factors That Modulate Severity Of Clostridioides Difficile Associated Disease, Armando Lerma

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Clostridioides difficile is recognized as one of the most important pathogens in hospital and community healthcare settings. The clinical outcome of infection of toxigenic C. difficile infection (CDI) ranges from asymptomatic colonization to fulminant pseudomembranous colitis and death. In recent studies, it has been suggested that a high proportion of nosocomial CDI cases are transmitted from asymptomatic carriers which might be acting as infection reservoirs. Understanding what causes the different responses to infection could lead to the development of novel prevention and treatment strategies. Although several explanations have been proposed to explain variations in susceptibility, understanding of the exact mechanisms …

Evaluation Of Semi-Quantitative Compared To Quantitative Cultures Of Tracheal Aspirates For The Yield Of Culturable Respiratory Pathogens - A Cross-Sectional Study, Salima Rattani, Joveria Farooqi, Ghazala Jabeen, Saeeda Chandio, Qaiser Kash, Aijaz Khan, Kauser Jabeen

Department of Pathology and Laboratory Medicine

Background: Diagnosis of lower respiratory tract infections (LRTI) depends on the presence of clinical, radiological and microbiological findings. Endotracheal suction aspirate (ETSA) is the commonest respiratory sample sent for culture from intubated patients. Very few studies have compared quantitative and semi-quantitative processing of ETSA cultures for LRTI diagnosis. We determined the diagnostic accuracy of quantitative and semi-quantitative ETSA culture for LRTI diagnosis, agreement between the quantitative and semi quantitative culture techniques and the yield of respiratory pathogens with both methods.
Methods: This was a cross-sectional study conducted at the Aga Khan University clinical laboratory, Karachi, Pakistan. One hundred and seventy-eight …

How Does Molecular Biology Help To Identify Plant Disease?, Madina Akramova

English Language Institute

This study examines a process of plant disease diagnostics in light of a particular method of molecular biology - polymerase chain reaction.

Repression Of Tick Microrna-133 Induces Organic Anion Transporting Polypeptide Expression Critical For Anaplasma Phagocytophilumsurvival In The Vector And Transmission To The Vertebrate Host, Ellango Ramasamy, Vikas Taank, John F. Anderson, Hameeda Sultana, Girish Neelakanta

Biological Sciences Faculty Publications

The microRNAs (miRNAs) are important regulators of gene expression. In this study, we provide evidence for the first time to show that rickettsial pathogen Anaplasma phagocytophilum infection results in the down-regulation of tick microRNA-133 (miR-133), to induce Ixodes scapularis organic anion transporting polypeptide (isoatp4056) gene expression critical for this bacterial survival in the vector and for its transmission to the vertebrate host. Transfection studies with recombinant constructs containing transcriptional fusions confirmed binding of miR-133 to isoatp4056 mRNA. Treatment with miR-133 inhibitor resulted in increased bacterial burden and isoatp4056 expression in ticks and tick cells. In contrast, treatment with …

Plant Defensin Antibacterial Mode Of Action Against Pseudomonas Species, Andrew E. Sathoff, Shawn Lewenza, Deborah A. Samac

Faculty Research & Publications

Background: Though many plant defensins exhibit antibacterial activity, little is known about their antibacterial mode of action (MOA). Antimicrobial peptides with a characterized MOA induce the expression of multiple bacterial outer membrane modifications, which are required for resistance to these membrane-targeting peptides. Mini-Tn5- lux mutant strains of Pseudomonas aeruginosa with Tn insertions disrupting outer membrane protective modifications were assessed for sensitivity against plant defensin peptides. These transcriptional lux reporter strains were also evaluated for lux gene expression in response to sublethal plant defensin exposure. Also, a plant pathogen, Pseudomonas syringae pv. syringae was modified through transposon mutagenesis to …

Contributions Of Gyra And Parc Mutations And Qnrs2 Acquisition To Ciprofloxacin Resistance In Aeromonas Veronii Hm21, Daniel J. Silverstein

Honors Scholar Theses

In recent years, ciprofloxacin resistant (CpR) Aeromonas veronii and A. hydrophila strains have been isolated from the wounds of patients receiving leech therapy. Genome comparisons of these CpR isolates revealed the presence of chromosomal mutations in gyrA and parC as well as the gain of qnrS2 on either a large, 34 kb, conjugatable, low-copy plasmid, pAv42, or on a small, 6.8 kb, high-copy plasmid, pAh1471. The minimum inhibitory concentration, MIC, for Cp of these clinical isolates ranged from 1 to ≥32 µg/mL and some harbored a qnrS2 containing plasmid. We wanted to assess the contributions of these factors in an …

Investigation Of Rapid Diagnostic Tests For Characterization Of Mycobacterium Avium Complex (Mac) From Various Isolates And Identification Of Virulence Factors Of Porcine Reproductive And Respiratory Syndrome Virus (Prrsv) In Vitro, Claudia Antonika

UCARE Research Products

Chapter 1

Mycobacterium avium complex (MAC) has become one of the major problems in public health and livestock. Members of MAC, such as M. avium subsp paratuberculosis (MAP) and M. avium subsp hominissuis (MAH), are responsible for many opportunistic infections and the loss of livestock. MAP is economically significant to the beef and dairy industries because it is the etiologic agent of Johnes’s disease, a chronic and fatal enteritis in ruminants. Tracing the infection sources of MAC could be difficult since it infects many types of hosts in the natural environment. Furthermore, there is less information known about MAP pathogenicity …

Microbiota Accessible Carbohydrates And Susceptibility To Clostridioides Difficile Infection, Keegan Schuchart, Jennifer Auchtung, Thomas Auchtung

UCARE Research Products

This experiment looked into the effects of dietary microbiota accessible carbohydrates (MACs)on the composition of human GI microbe colonies and their susceptibility to pathogen infection. Three different concentrations of MAC ingrained media were tested in mini bioreactor arrays, treated with antibiotics, infected with Clostridioides difficile, then allowed to recover. Microbe community was examined for strain composition and diversity before and after the antibiotic treatment and Clostridioides difficile infection. After the initial mini bioreactor run, individual isolates were investigated in their ability to respond to specific MACs Arabinoglactina, Inulin, and Soluble starch at experimental concentrations.

Biological Sex Influences Susceptibility To Acinetobacter Baumannii Pneumonia In Mice, Sílvia Pires, Adeline Peignier, Jeremy Seto, Davida S. Smyth, Dane Parker

Publications and Research

Acinetobacter baumannii (A. baumannii) is an extremely versatile multidrug-resistant pathogen with a very high mortality rate; therefore, it has become crucial to understand the host response during its infection. Given the importance of mice for modeling infection and their role in preclinical drug development, equal emphasis should be placed on the use of both sexes. Through our studies using a murine model of acute pneumonia with A. baumannii, we observed that female mice were more susceptible to infection. Likewise, treatment of male mice with estradiol increased their susceptibility to infection. Analysis of the airway compartment revealed enhanced inflammation and reduced …

Histidine-Triad Hydrolases Provide Resistance To Peptide-Nucleotide Antibiotics., Eldar Yagmurov, Darya Tsibulskaya, Alexey Livenskyi, Marina Serebryakova, Yury I Wolf, Sergei Borukhov, Konstantin Severinov, Svetlana Dubiley

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The Escherichia coli microcin C (McC) and related compounds are potent Trojan horse peptide-nucleotide antibiotics. The peptide part facilitates transport into sensitive cells. Inside the cell, the peptide part is degraded by nonspecific peptidases releasing an aspartamide-adenylate containing a phosphoramide bond. This nonhydrolyzable compound inhibits aspartyl-tRNA synthetase. In addition to the efficient export of McC outside the producing cells, special mechanisms have evolved to avoid self-toxicity caused by the degradation of the peptide part inside the producers. Here, we report that histidine-triad (HIT) hydrolases encoded in biosynthetic clusters of some McC homologs or by standalone genes confer resistance to McC-like …

Fungicide Sensitivity Of Sclerotinia Sclerotiorum Isolates Selected From Five Different States That Use Different Fungicide Treatments, Cristian Wulkop Gil

UCARE Research Products

Sclerotinia sclerotiorum is a plant pathogenic fungus that causes a disease called white mold that can infect more than 450 plant species including soybeans, dry beans, green beans, canola, and sunflower. This pathogen is capable of up to $252M in losses every year (U.S. Canola Association, 2014). Fungicides are widely used in developed agricultural systems to control disease. However, resistance to the most effective fungicides has emerged and spread in pathogen populations and there have been multiple reports of S. sclerotiorum isolates becoming resistant to certain fungicides. Since different fields in different states use different fungicide treatments on plants and …

On The Inadequacy Of Species Distribution Models For Modelling The Spread Of Sars-Cov-2: Response To Araújo And Naimi, Joseph D. Chipperfield, Blas M. Benito, Robert B. O'Hara, Richard J. Telford, Colin J. Carlson

Public Health Resources

The ongoing pandemic of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing significant damage to public health and economic livelihoods, and is putting significant strains on healthcare services globally. This unfolding emergency has prompted the preparation and dissemination of the article “Spread of SARS-CoV-2 Coronavirus likely to be constrained by climate” by Araújo and Naimi (2020). The authors present the results of an ensemble forecast made from a suite of species distribution models (SDMs), where they attempt to predict the suitability of the climate for the spread of SARS-CoV-2 over the coming months. They argue that climate is …

Listeria Monocytogenes Response To Anaerobic Environments, Brandy N. Roberts, Damayanti Chakravarty, J.C. Gardner Iii, Steven C. Ricke, Janet R. Donaldson

Faculty Publications

Listeria monocytogenes is a Gram-positive facultative anaerobic bacterium that is responsible for the disease, listeriosis. It is particularly lethal in pregnant women, the fetus, the elderly and the immunocompromised. The pathogen survives and replicates over a wide range of temperatures (4 to 42 °C), pH, salt and oxygen concentrations. Because it can withstand various environments, L. monocytogenes is a major concern in food processing industries, especially in dairy products and ready-to-eat fruits, vegetables and deli meats. The environment in which the pathogen is exposed can influence the expression of virulence genes. For instance, studies have shown that variations in oxygen …

A High-Fat/High-Protein, Atkins-Type Diet Exacerbates Clostridioides (Clostridium) Difficile Infection In Mice, Whereas A High-Carbohydrate Diet Protects, Chrisabelle C. Mefferd, Shrikant S. Bhute, Jacqueline R. Phan, Jacob V. Villarama, Dung M. Do, Stephanie Alarcia, Ernesto Abel-Santos, Brian P. Hedlund

Chemistry and Biochemistry Faculty Research

Clostridioides difficile (formerly Clostridium difficile) infection (CDI) can result from the disruption of the resident gut microbiota. Western diets and popular weight-loss diets drive large changes in the gut microbiome; however, the literature is conflicted with regard to the effect of diet on CDI. Using the hypervirulent strain C. difficile R20291 (RT027) in a mouse model of antibiotic-induced CDI, we assessed disease outcome and microbial community dynamics in mice fed two high-fat diets in comparison with a high-carbohydrate diet and a standard rodent diet. The two high-fat diets exacerbated CDI, with a high-fat/high-protein, Atkins-like diet leading to severe CDI and …

Neurodevelopment Outcome Of Neonates Treated With Intraventricular Colistin For Ventriculitis Caused By Multiple Drug-Resistant Pathogens-A Case Series, Kashif Hussain, Muhammad Sohail Salat, Gul Ambreen, Javaid Iqbal

Department of Biological & Biomedical Sciences

Background: Multiple-drug-resistant Gram-negative bacteria (MDR-GNB)-associated neonatal ventriculitis is a life-threatening complication that needs timely diagnosis and effective treatment with broad-spectrum antimicrobials in critical-care settings. Inadequate penetration of antibiotics through the blood-brain barrier also demands an intraventricular (IVT) route of administration. This study reports mortality and neurodevelopmental sequelae of neonates till 18 months of age, who received IVT-colistin for treating MDR-GNB associated ventriculitis.
Methods: In a case series of seven neonates with ventriculitis due to MDR-GNB at NICU of Aga Khan University Hospital, Pakistan, between June 2015 and 2018, we reviewed IVT-colistin therapy in critically ill neonates. Treatment outcomes were assessed …