spp. are a genus of bacteria for which two human-associated species exist:
and
Their definition as a pathogen in the context of nongonococcal urethritis (NGU) and infertility among males remains ...highly controversial, largely due to historically high rates of isolation of these bacteria from the urethra of seemingly healthy men. This review summarizes the emerging evidence suggesting a true pathogenic role of these bacteria under specific conditions, which we term risk factors. We examine the historical, clinical, and experimental studies which support a causal role for
spp. in the development of NGU as well as some of the proposed mechanisms behind the association of
spp. and the development of infertility. Finally, we discuss the potential for developing a case-by-case risk-based approach toward the management of men who present with seemingly idiopathic NGU but who are positive for
spp.
Biofilm-related bacterial infections pose a significant problem, as they are generally more tolerant to antibiotics and the immune system. Development of novel compounds with antibiofilm activity is ...therefore paramount. In this study we have analysed metal complexes of the general structure M(IL)(AL)2+ (where IL represents functionalised 1,10-phenanthrolines and AL represents 1S,2S- or 1R,2R-diaminocyclohexane) and Cu(IL)32+. Antimicrobial activity was tested on a number of bacterial strains, showing that copper(II) compounds were active against both Gram-positive and Gram-negative bacteria, albeit that activity was generally higher for the former. The antibiofilm activity was then determined against a clinical isolate of meticillin-resistant Staphylococcus aureus (MRSA). Strikingly, the copper complexes tested showed significant activity against biofilms, and were better in the removal of biofilms than vancomycin, an antibiotic that is currently used in the treatment of MRSA infections.
The compound Cu(56Me2phen)(SS-dachCl2 demonstrates effective biofilm killing and removal capabilities against 24h MRSA biofilms. Left panel shows an untreated biofilm and right panel shows a biofilm treated with the Cu(II) compound (live cells stain green; dead cells stain red). Display omitted
Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can ...also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates. In contrast, P. asymbiotica must necessarily be able to replicate at 37°C or above. Many well-studied mammalian pathogens use the elevated temperature of their host as a signal to regulate the necessary changes in gene expression required for infection. Here we use RNA-seq, proteomics and phenotype microarrays to examine temperature dependent differences in transcription, translation and phenotype of P. asymbiotica at 28°C versus 37°C, relevant to the insect or human hosts respectively. Our findings reveal relatively few temperature dependant differences in gene expression. There is however a striking difference in metabolism at 37°C, with a significant reduction in the range of carbon and nitrogen sources that otherwise support respiration at 28°C. We propose that the key adaptation that enables P. asymbiotica to infect humans is to aggressively acquire amino acids, peptides and other nutrients from the human host, employing a so called "nutritional virulence" strategy. This would simultaneously cripple the host immune response while providing nutrients sufficient for reproduction. This might explain the severity of ulcerated lesions observed in clinical cases of Photorhabdosis. Furthermore, while P. asymbiotica can invade mammalian cells they must also resist immediate killing by humoral immunity components in serum. We observed an increase in the production of the insect Phenol-oxidase inhibitor Rhabduscin normally deployed to inhibit the melanisation immune cascade. Crucially we demonstrated this molecule also facilitates protection against killing by the alternative human complement pathway.
Highlights • 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 hyperammonemia.
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.
Abstract
Objectives
To determine the phenotypic and genotypic antibiotic susceptibility of Mycoplasma amphoriforme isolates recovered from patients in the UK and Denmark.
Methods
Seven isolates of M. ...amphoriforme were examined for antimicrobial susceptibility to seven antibiotics using the microbroth dilution assay in line with the CLSI guidelines for mycoplasmas. Each isolate was additionally subjected to WGS to identify resistance-associated mutations. Based on the consensus sequences from the genomic data, PCR primers were designed, and tested, for the amplification of the QRDR within the parC gene.
Results
Of the seven isolates investigated, four (57%) were resistant to moxifloxacin (0.5–1 mg/L) and levofloxacin (1–2 mg/L), compared with those that were susceptible (0.03–0.06 and 0.006 mg/L, respectively). Isolate H29 was resistant to five of the seven antibiotics tested: moxifloxacin, 0.5 mg/L; levofloxacin, 2 mg/L; azithromycin, 64 mg/L; erythromycin, 128 mg/L; and clindamycin, 64 mg/L. All isolates were susceptible to tetracycline (0.06 mg/L) and lefamulin (0.001–0.004 mg/L). Mutations from genomic data confirmed the presence of an S89F mutation within the ParC protein among all fluoroquinolone-resistant isolates and an A2059G mutation in the 23S rRNA gene in the macrolide- and lincosamide-resistant isolate H29.
Conclusions
To the best of our knowledge, this is the first time where phenotypic and genotypic resistance data have been paired for M. amphoriforme confirming a correlation between the two. These data suggest the need for focused testing and resistance determination of isolates from high-risk patients given the backdrop of a high prevalence of antimicrobial resistance.
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.
is a Gram-positive intracellular pathogen that can cause listeriosis, an invasive disease affecting pregnant women, neonates, the elderly, and immunocompromised individuals. Principally foodborne, ...the pathogen is transmitted typically through contaminated foods. As a result, food manufacturers exert considerable efforts to eliminate
from foodstuffs and the environment through food processing and disinfection. However,
demonstrates a range of environmental stress tolerances, resulting in persistent colonies that act as reservoirs for the reintroduction of
to food contact surfaces and food. Novel technologies for the rapid detection of
and disinfection of food manufacturing industries have been developed to overcome these obstacles to minimise the risk of outbreaks and sporadic cases of listeriosis. This review is aimed at exploring
in the UK, providing a summary of outbreaks, current routine microbiological testing and the increasing awareness of biocide tolerances. Recommendations for future research in the UK are made, pertaining to expanding the understanding of
dissemination in the UK food industry and the continuation of novel technological developments for disinfection of food and the food manufacturing environment.
Understanding chronic wound infection is key for successful treatment and requires accurate laboratory models. We describe a modified biofilm flow device that effectively mimics the chronic wound ...environment, including simulated wound fluid, a collagen-based 3D biofilm matrix, and a five-species mixture of clinically relevant bacteria (
,
,
,
, and
). Mixed biofilms were cultured for between 3 and 14 days with consistent numbers of bacteria that exhibited reduced metabolic activity, which increased with a high dose of glucose.
was recovered from biofilms as a small colony variant, but as a normal colony variant if
was excluded from the system. Bacteria within the biofilm did not co-aggregate but formed discrete, species-specific clusters. Biofilms demonstrated differential tolerance to the topical antimicrobials Neosporin and HOCl, consistent with protection due to the biofilm lifestyle. The characteristics exhibited within this model match those of real-world wound biofilms, reflecting the clinical scenario and yielding a powerful in vitro tool that is versatile, inexpensive, and pivotal for understanding chronic wound infection.
To determine the presence and genotypic macrolide susceptibility of Mycoplasma amphoriforme, and the presence of Ureaplasma spp. and Mycoplasma fermentans among clinical samples from England ...previously investigated for Mycoplasma pneumoniae.
Quantitative and conventional PCR methods were used to retrospectively screen a collection of 160 clinical samples previously submitted to Public Health England (PHE) for the detection of M. pneumoniae between October 2016 and December 2017. Samples which were positive for M. amphoriforme DNA were further investigated for mutations associated with genotypic macrolide resistance by sequencing domain V of the 23s rRNA.
M. amphoriforme was detected in 10/160 samples (6.3%), Ureaplasma parvum was detected in 4/160 samples (2.5%), and M. fermentans was not detected in any samples (0/160). Of the nine individuals (two samples were from the same patient) in which M. amphoriforme was detected, eight were male (age range 10–60 years) and one was female (age range 30–40 years). One individual with cystic fibrosis was positive for both M. amphoriforme and U. parvum. All M. amphoriforme DNA was genotypically susceptible to macrolides.
Mycoplasma amphoriforme was found in clinical samples, including lower respiratory tract samples of patients with pneumonia. In the absence of other respiratory pathogens, these data suggest a potential role for this organism in human disease, with no evidence of acquired macrolide resistance. Ureaplasma parvum was detected in cerebrospinal fluid and respiratory tract samples. These data suggest that there is a need to consider these atypical respiratory pathogens in future diagnostic investigations.
PDF
