Search

Mycoplasma genitalium is an emerging global health threat, due to an alarming rise in antimicrobial resistance. Although individualised treatment approaches have been successfully adopted for macrolides, treatment is complicated by rising rates of fluoroquinolone resistance and by the scarcity of alternative treatment options. In this Personal View, we discuss the available data within the literature and highlight issues surrounding individualised treatment using fluoroquinolones, including the hesitation to focus on inclusion of ParC fluoroquinolone resistance mutations for guiding antimicrobial treatments. We propose that there is a clear role for diagnostics that focus on the absence of resistance mutations (ie, wild-type sequences and antimicrobial susceptibility) to inform microbial cure following fluoroquinolone antimicrobials, with Australian data strongly supporting this approach. The development of molecular tests that incorporate markers to detect both wild-type and only the most common ParC mutation, Ser83Ile, could greatly improve first-line antimicrobial selection and stewardship, individualise tests of cure, and be extremely useful in the care of patients with M genitalium infection. [ABSTRACT FROM AUTHOR]

Abstract A new capsular polysaccharide (CPS) biosynthesis gene cluster, KL16, was found in the genome sequence of a clinical Acinetobacter baumannii ST25 isolate, D4. The variable part of KL16 contains a module of genes for synthesis of 5,7-diacetamido-3,5,7,9-tetradeoxy- l - glycero - l - manno -non-2-ulosonic acid (5,7-di- N -acetylpseudaminic acid, Pse5Ac7Ac), a gene encoding ItrA3 that initiates the CPS synthesis with d -Glc p NAc, and two glycosyltransferase (Gtr) genes. The K16 CPS was studied by sugar analysis and Smith degradation along with 1D and 2D 1H and 13C NMR spectroscopy, and shown to be built up of linear trisaccharide repeats containing d -galactose (d -Gal), N -acetyl- d -glucosamine (d -GlcNAc), and Pse5Ac7Ac. The d -Gal p residue is linked to the d -Glc p NAc initiating sugar via a β-(1 → 3) linkage evidently formed by a Gtr5 variant, Gtr5 K16 , encoded in KL16. This reveals an altered or relaxed substrate specificity of this variant as the majority of Gtr5-type glycosyltransferases have previously been shown to form a β- d -Gal p -(1 → 3)- d -Gal p NAc linkage. The β-Pse p 5Ac7Ac-(2 → 4)- d -Gal p linkage is predicted to be formed by the other glycosyltransferase, Gtr37, which does not match members of any known glycosyltransferase family. [ABSTRACT FROM AUTHOR]

Background: Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality and is not uncommonly associated with chorioamnionitis. We recently have demonstrated that the placenta harbors a unique microbiome with similar flora to the oral community. We also have shown an association of these placental microbiota with PTB, history of antenatal infection, and excess maternal weight gain. On the basis of these previous observations, we hypothesized that the placental membranes would retain a microbiome community that would vary in association with preterm birth and chorioamnionitis.Objective: In the current study, we aimed to examine the differences in the placental membrane microbiome in association with PTB in both the presence and absence of chorioamnionitis and/or funisitis using state-of-the-science whole-genome shotgun metagenomics.Study Design: This was a cross-sectional analysis with 6 nested spontaneous birth cohorts (n = 9-15 subjects/cohort): Term gestations without chorioamnionitis, term with chorioamnionitis, preterm without chorioamnionitis, preterm with mild chorioamnionitis, preterm with severe chorioamnionitis, and preterm with chorioamnionitis and funisitis. Histologic analysis was performed with Redline's criteria, and inflammatory cytokines were analyzed in the cord blood. DNA from placental membranes was extracted from sterile swabs collected at delivery, and whole-genome shotgun sequencing was performed on the Illumina HiSeq platform. Filtered microbial DNA sequences were annotated and analyzed with MG-RAST (ie, Metagenomic Rapid Annotations using Subsystems Technology) and R.Results: Subjects were assigned to cohorts on the basis of gestational age at delivery and independent scoring of histologic chorioamnionitis. We found that preterm subjects with severe chorioamnionitis and funisitis had increases in cord blood inflammatory cytokines. Of interest, although the placental membrane microbiome was altered in association with severity of histologic chorioamnionitis (permutational multivariate analysis of variance P = .005), there was no observable impact with either betamethasone or antibiotic treatment. In preterm subjects with chorioamnionitis, we found a high abundance of both urogenital and oral commensal bacteria. These alterations in the microbiome were accompanied by significant variation (P < .05) in microbial metabolic pathways important in the glucose-fed pentose phosphate pathway (term subjects), or glycerophopholipid metabolism, and the biosynthesis of the siderophore group nonribosomal peptides (preterm subjects).Conclusion: Consistent with ours and others previous findings, women who experienced spontaneous PTB harbor placental microbiota that further differed by severity of chorioamnionitis. Integrative metagenomic analysis revealed significant variation in distinct bacterial metabolic pathways, which we speculate may contribute to risk of preterm birth with and without severe chorioamnionitis. [ABSTRACT FROM AUTHOR]