Possible missed diagnosis of Ureaplasma spp infection in a case of fatal hyperammonemia after repeat renal transplantation

•Ureaplasma spp are associated with complications among renal transplant patients. •Ureaplasma spp may have been the cause of fatal hyperammonemia. •Specific culture conditions or molecular methods are required to detect Ureaplasma. •Appropriate antimicrobial therapy can resolve symptoms of hyperammonemi

Role of ureaplasma spp in neonatal lung disease, activation of the complement system and molecular mechanisms of antibiotic resistance

Ureaplasmas are some of the smallest and simplest free-living organisms known. Little is understood regarding the effects of the complement system upon clearance of these pathogens, but when the immune system fails to control Ureaplasma colonization disease, such as chronic lung disease of prematurity (CLD), can occur. Treatment of such Ureaplasma infections, especially in neonates, is limited by pathogen and host factors. Treatment can be further compromised by antibiotic resistance. Firstly this thesis examines an in vitro system for determining the bactericidal capacity of a selection of human sera against four representative serovars of Ureaplasma parvum. Results showed that the classical activation pathway was essential for the killing of all U. parvum serovars, with little effect being attributed to the alternative or lectin pathways. Additionally serovar 3 was shown to be the most serum sensitive isolate. Secondly the association between presence of Ureaplasma and 16S rRNA with development of CLD was examined in a prospective cohort of 192 neonates. Data suggested that presence of Ureaplasma as well as 16S rRNA was significantly associated with development of CLD as well as increased levels of inflammatory mediators IL-6 and IL-8. Finally a retrospective cohort of 61 Ureaplasma isolates was examined for resistance to various antibiotics. High level macrolide resistance in isolate UHWO10 resulted from a two amino acid deletion within the L4 ribosomal protein (R66Q67). Tetracycline resistance in isolate HPA23 resulted from the presence of the tetM gene while a ciprofloxacin resistance in isolate HPA18 resulted from a D82N substitution within the ParC protein. No differences were found in the GyrA, GyrB or ParE proteins. Comparison of type II topoisomerase genes from all Ureaplasma serovars revealed that mutations previously associated with resistance where wrongly identified and were a result of species or serovar specific polymorphisms.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Role of ureaplasma spp in neonatal lung disease, activation of the complement system and molecular mechanisms of antibiotic resistance

Ureaplasmas are some of the smallest and simplest free-living organisms known. Little is understood regarding the effects of the complement system upon clearance of these pathogens, but when the immune system fails to control Ureaplasma colonization disease, such as chronic lung disease of prematurity (CLD), can occur. Treatment of such Ureaplasma infections, especially in neonates, is limited by pathogen and host factors. Treatment can be further compromised by antibiotic resistance. Firstly this thesis examines an in vitro system for determining the bactericidal capacity of a selection of human sera against four representative serovars of Ureaplasma parvum. Results showed that the classical activation pathway was essential for the killing of all U. parvum serovars, with little effect being attributed to the alternative or lectin pathways. Additionally serovar 3 was shown to be the most serum sensitive isolate. Secondly the association between presence of Ureaplasma and 16S rRNA with development of CLD was examined in a prospective cohort of 192 neonates. Data suggested that presence of Ureaplasma as well as 16S rRNA was significantly associated with development of CLD as well as increased levels of inflammatory mediators IL-6 and IL-8. Finally a retrospective cohort of 61 Ureaplasma isolates was examined for resistance to various antibiotics. High level macrolide resistance in isolate UHWO10 resulted from a two amino acid deletion within the L4 ribosomal protein (R66Q67). Tetracycline resistance in isolate HPA23 resulted from the presence of the tetM gene while a ciprofloxacin resistance in isolate HPA18 resulted from a D82N substitution within the ParC protein. No differences were found in the GyrA, GyrB or ParE proteins. Comparison of type II topoisomerase genes from all Ureaplasma serovars revealed that mutations previously associated with resistance where wrongly identified and were a result of species or serovar specific polymorphisms

The role of Ureaplasma spp. in the development of non-gonococcal urethritis and infertility among men

Ureaplasma spp. are a genus of bacteria for which two human associated species exist; Ureaplasma urealyticum and Ureaplasma parvum. Their definition as a pathogen in the context of non-gonococcal urethritis and infertility among males remains highly controversial, largely due to historically high isolation rates of these bacteria from the urethra of seemingly healthy men. This review summarises the emerging evidence suggesting a true pathogenic role of these bacteria under specific conditions, which we term as risk factors. We examine the historical, clinical and experimental studies which support a causal role for Ureaplasma spp in the development of NGU as well as some of the proposed mechanisms behind the association of Ureaplasma spp. and the development of infertility. Finally, we discuss the potential for developing a case-by-case risk-based approach towards the management of men who present with seemingly idiopathic NGU, but are positive for Ureaplasma spp

Electrospun Zein/PCL Fibrous Matrices Release Tetracycline in a Controlled Manner, Killing Staphylococcus aureus Both in Biofilms and Ex Vivo on Pig Skin, and are Compatible with Human Skin Cells

PURPOSE: To investigate the destruction of clinically-relevant bacteria within biofilms via the sustained release of the antibiotic tetracycline from zein-based electrospun polymeric fibrous matrices and to demonstrate the compatibility of such wound dressing matrices with human skin cells. METHODS: Zein/PCL triple layered fibrous dressings with entrapped tetracycline were electrospun. The successful entrapment of tetracycline in these dressings was validated. The successful release of bioactive tetracycline, the destruction of preformed biofilms, and the viability of fibroblast (FEK4) cells were investigated. RESULTS: The sustained release of tetracycline from these matrices led to the efficient destruction of preformed biofilms from Staphylococcus aureus MRSA252 in vitro, and of MRSA252 and ATCC 25923 bacteria in an ex vivo pig skin model using 1 × 1 cm square matrices containing tetracycline (30 μg). Human FEK4 cells grew normally in the presence of these matrices. CONCLUSIONS: The ability of the zein-based matrices to destroy bacteria within increasingly complex in vitro biofilm models was clearly established. An ex vivo pig skin assay showed that these matrices, with entrapped tetracycline, efficiently kill bacteria and this, combined with their compatibility with a human skin cell line suggest these matrices are well suited for applications in wound healing and infection control

Relationship of Proteinases and Proteinase Inhibitors with Microbial Presence in Chronic Lung Disease of Prematurity

Background: A proteolytic imbalance has been implicated in the development of “classical” chronic lung disease of prematurity (CLD). However, in “new” CLD this pattern has changed. This study examines the longitudinal relationship between neutrophil proteinases and their inhibitors in ventilated preterm infants and their relationship to microbial colonisation. Methods: Serial bronchoalveolar lavage fluid was obtained from ventilated newborn preterm infants. Neutrophil elastase (NE) activity, cell counts, metalloproteinase (MMP)-9, MMP-9/TIMP-1 complex, SerpinB1 concentration and percentage of SerpinB1 and α1-antitrypsin (AAT) in complex with elastase were measured. The presence of microbial genes was examined using PCR for 16S rRNA genes. Results: Statistically more infants who developed CLD had NE activity in at least one sample (10/20) compared with infants with resolved respiratory distress syndrome (RDS) (2/17). However, NE activity was present in a minority of samples, occurring as episodic peaks. Peak levels of MMP-9, MMP-9/TIMP-1 complex, percentage of AAT and SerpinB1 in complex and cell counts were all statistically greater in infants developing CLD than in infants with resolved RDS. Peak values frequently occurred as episodic spikes and strong temporal relationships were noted between all markers. The peak values for all variables were significantly correlated to each other. The presence of bacterial 16S rRNA genes was associated with the development of CLD and with elevated elastase and MMP-9. Conclusion: NE activity and MMP-9 appear to be important in the development of “new” CLD with both proteinase and inhibitor concentrations increasing episodically, possibly in response to postnatal infection

Antibiotic resistance among clinical Ureaplasma Isolates Recovered from Neonates in England and Wales between 2007 and 2013

Ureaplasma spp. are associated with numerous clinical sequelae with treatment options being limited due to patient and pathogen factors. This report examines the prevalence and mechanisms of antibiotic resistance among clinical strains isolated from 95 neonates, 32 women attending a sexual health clinic, and 3 patients under investigation for immunological disorders, between 2007 and 2013 in England and Wales. MICs were determined by using broth microdilution assays, and a subset of isolates were compared using the broth microdilution method and the Mycoplasma IST2 assay. The underlying molecular mechanisms for resistance were determined for all resistant isolates. Three isolates carried the tet(M) tetracycline resistance gene (2.3%; confidence interval [CI], 0.49 to 6.86%); two isolates were ciprofloxacin resistant (1.5%; CI, 0.07 to 5.79%) but sensitive to levofloxacin and moxifloxacin, while no resistance was seen to any macrolides tested. The MIC values for chloramphenicol were universally low (2 μg/ml), while inherently high-level MIC values for gentamicin were seen (44 to 66 μg/ml). The Mycoplasma IST2 assay identified a number of false positives for ciprofloxacin resistance, as the method does not conform to international testing guidelines. While antibiotic resistance among Ureaplasma isolates remains low, continued surveillance is essential to monitor trends and threats from importation of resistant clones