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

Antibiotic resistance among Ureaplasma spp isolates: cause for concern?

There is growing global concern regarding the rise of antibiotic-resistant organisms. Many of these reports have focused on various Gram-positive and Gram-negative pathogens, with little attention to the genus Ureaplasma. Ureaplasma spp. are associated with numerous infectious diseases affecting pregnant women, neonates and the immunocompromised. Treatment options are extremely limited due to high levels of intrinsic resistance resulting from the unique physiology of these organisms and further restricted in cases of the developing fetus or neonate, often limiting therapeutic options to predominantly macrolides or rarely fluoroquinolones. The increasing presence of macrolide- and fluoroquinolone-resistant strains among neonatal infections may result in pan-drug resistance and potentially untreatable conditions. Here, we review the requirements for accurate measurement of antimicrobial susceptibility, provide a comprehensive review of the antimicrobial resistance (AMR) for Ureaplasma species in the literature and contextualize these results relative to some investigators' reliance on commercial kits that are not CLSI compliant when determining AMR. The dramatic variation in the resistance patterns and impact of high levels of AMR amongst neonatal populations suggests the need for continued surveillance. Commercial kits represent an excellent tool for initial antibiotic susceptibility determination and screening. However, AMR reporting must utilize internationally standardized methods, as high-titre samples, or Mycoplasma hominis-contaminated samples routinely give false AMR results. Furthermore, there is a requirement for future reports to determine the underlying AMR mechanisms and determine whether expanding AMR is due to spontaneous mutation, transmission of resistance genes on mobile elements or selection and expansion of resistant clones

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

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

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