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1.
J Infect Dis ; 221(6): 1017-1024, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32031634

RESUMO

BACKGROUND: The basis of fluoroquinolone treatment failure for Mycoplasma genitalium is poorly understood. METHODS: To identify mutations associated with failure we sequenced key regions of the M. genitalium parC and gyrA genes for patients undergoing sequential therapy with doxycycline-moxifloxacin (201 patients, including 21 with failure) or doxycycline-sitafloxacin (126 patients, including 13 with failure). RESULTS: The parC G248T/S83I mutation was more common among patients with failed sequential doxycycline-moxifloxacin (present in 76.2% of failures vs 7.8% cures, P < .001) or doxycycline-sitafloxacin (50% vs 16.8%, respectively; P = .01) treatment. Doxycycline-sitafloxacin was more efficacious than doxycycline-moxifloxacin against infections carrying the parC mutation conferring S83I amino acid change. Treatment was more likely to fail in these infections if they had a concurrent gyrA mutation (M95I or D99N) (P = .07 for doxycycline-moxifloxacin group and P = .009 for doxycycline-sitafloxacin group), suggesting an additive effect. CONCLUSIONS: This study indicates that parC G248T/S83I mutations contribute to failure of moxifloxacin and sitafloxacin, and the findings will inform the development of quinolone resistance assays needed to ensure optimal selection of antimicrobials for M. genitalium.

2.
J Med Microbiol ; 69(2): 244-248, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31958047

RESUMO

Introduction. Mycoplasma genitalium is a sexually transmitted organism with high levels of resistance to the recommended first-line therapy, azithromycin. The ResistancePlus MG test concurrently detects M. genitalium, and the presence of macrolide-resistance mutations (MRM). European, UK and Australian guidelines recommend a diagnostic test that reports MRM to optimize treatment through resistance-guided therapy. Hence, for samples collected for use on other platforms, reflex testing using the ResistancePlus MG test would be beneficial.Aim. To validate the ResistancePlus MG assay using samples collected in Aptima buffer for testing on the Hologic Panther.Methodology. Positive (n=99) and negative (n=229) clinical samples collected in Aptima buffer were extracted on the MagNA Pure 96 (Roche Diagnostics), and tested with the ResistancePlus MG test on the LightCycler 480 II (Roche Diagnostics). Results were compared to matched samples collected using standard sample collection (urine or swab resuspended in PBS), with positive percent agreement (PPA), negative percent agreement (NPA) and Cohen's Kappa statistic.Results. The ResistancePlus MG test had high performance with a 200 µl input volume (PPA/NPA for M. genitalium detection, 92.9 % [95 % confidence interval (CI): 85.5-96.9]/100 % [95 % CI: 97.9-100], MRM detection, 96.9 % [95 % CI: 88.2-99.5]/85.7 % [95 % CI: 66.4-95.3]) and for 1 ml input volume (PPA/NPA for M. genitalium detection, 95.9%/96.6%, MRM detection, 98.4%/90.3%). Samples remained positive after storage at room temperature beyond the manufacturer-recommended storage of <60 days (mean storage time for 1 ml extraction: 129 days).Conclusion. Samples collected using Aptima collection kits are suitable for reflex testing using the ResistancePlus MG test, allowing detection of macrolide resistance.


Assuntos
Antibacterianos/farmacologia , Testes Diagnósticos de Rotina/métodos , Farmacorresistência Bacteriana , Infecções por Mycoplasma/microbiologia , Mycoplasma genitalium/efeitos dos fármacos , Mycoplasma genitalium/isolamento & purificação , Austrália , Testes Diagnósticos de Rotina/instrumentação , Humanos , Macrolídeos/farmacologia , Infecções por Mycoplasma/diagnóstico , Mycoplasma genitalium/genética , Kit de Reagentes para Diagnóstico , Manejo de Espécimes
3.
J Infect Dis ; 221(3): 454-463, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31544206

RESUMO

BACKGROUND: Gardnerella vaginalis is detected in women with and without bacterial vaginosis (BV). Identification of 4 G. vaginalis clades raised the possibility that pathogenic and commensal clades exist. We investigated the association of behavioral practices and Nugent Score with G. vaginalis clade distribution in women who have sex with women (WSW). METHODS: Longitudinal self-collected vaginal specimens were analyzed using established G. vaginalis species-specific and clade-typing polymerase chain reaction assays. Logistic regression assessed factors associated with detection of G. vaginalis clades, and multinomial regression assessed factors associated with number of clades. RESULTS: Clades 1, 2, and 3 and multiclade communities (<2 clades) were associated with Nugent-BV. Clade 1 (odds ratio [OR], 3.36; 95% confidence interval [CI], 1.65-6.84) and multiclade communities (relative risk ratio [RRR], 9.51; 95% CI, 4.36-20.73) were also associated with Lactobacillus-deficient vaginal microbiota. Clade 4 was neither associated with Nugent-BV nor Lactobacillus-deficient microbiota (OR, 1.49; 95% CI, 0.67-3.33). Specific clades were associated with differing behavioral practices. Clade 1 was associated with increasing number of recent sexual partners and smoking, whereas clade 2 was associated with penile-vaginal sex and sharing of sex toys with female partners. CONCLUSIONS: Our results suggest that G. vaginalis clades have varying levels of pathogenicity in WSW, with acquisition occurring through sexual activity. These findings suggest that partner treatment may be an appropriate strategy to improve BV cure.

4.
Sci Rep ; 9(1): 19749, 2019 12 24.
Artigo em Inglês | MEDLINE | ID: mdl-31874964

RESUMO

Women-who-have-sex-with-women (WSW) are at increased risk of bacterial vaginosis (BV). We investigated the impact of practices and past BV on the vaginal microbiota within a two-year longitudinal cohort of Australian WSW. Self-collected vaginal swabs were used to characterise the vaginal microbiota using 16S-rRNA gene sequencing. Hierarchical clustering defined community state types (CSTs). Bacterial diversity was calculated using the Shannon diversity index and instability of the vaginal microbiota was assessed by change of CST and Bray-Curtis dissimilarity. Sex with a new partner increased the bacterial diversity (adjusted-coefficient = 0.41, 95%CI: 0.21,0.60, p < 0.001) and instability of the vaginal microbiota, in terms of both change of CST (adjusted-odds-ratio = 2.65, 95%CI: 1.34,5.22, p = 0.005) and increased Bray-Curtis dissimilarity (adjusted-coefficient = 0.21, 95%CI: 0.11,0.31, p < 0.001). Women reporting sex with a new partner were more likely than women reporting no new partner to have a vaginal microbiota characterised by Gardnerella vaginalis (adjusted-relative-risk-ratio[aRRR] = 3.45, 95%CI: 1.42,8.41, p = 0.006) or anaerobic BV-associated bacteria (aRRR = 3.62, 95%CI: 1.43,9.14, p = 0.007) relative to a Lactobacillus crispatus dominated microbiota. Sex with a new partner altered the vaginal microbiota of WSW by increasing the diversity and abundance of BV-associated bacteria. These findings highlight the influence of practices on the development of a non-optimal vaginal microbiota and provide microbiological support for the sexual exchange of bacteria between women.

5.
Vaccine ; 37(43): 6271-6275, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31521414

RESUMO

The Victorian Government introduced a time-limited quadrivalent human papillomavirus (HPV) vaccination catch-up program targeting gay and bisexual men who have sex with men (MSM) aged up to 26 years in 2017. As of 2017, men aged ≥20 years were not eligible for the school-based HPV vaccination program. This study examined the prevalence of anal HPV among 496 MSM aged 20-26 years before they received the first dose of the HPV vaccine at the Melbourne Sexual Health Centre, Australia. More than half (56.5%) had any high-risk HPV genotypes detected in the anus. Almost half (43.1%) had at least one quadrivalent HPV vaccine-preventable genotype (6, 11, 16 or 18) and one-fifth (21.0%) had HPV 16 detected in the anus. These findings suggest that a targeted catch-up HPV vaccination program for MSM is still beneficial to protect against high-risk HPV genotypes associated with anal cancer, as well as low-risk HPV genotypes.

6.
J Clin Microbiol ; 57(11)2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31434719

RESUMO

Mycoplasma genitalium causes a common sexually transmitted infection with a marked propensity to develop antimicrobial resistance. As few treatment options exist, this poses significant challenges to clinicians. Recent diagnostic advances have resulted in tests that report the simultaneous detection of M. genitalium and any resistance to macrolides, the first-line treatment. This allows for therapy to be tailored to the individual, thereby optimizing treatment outcomes. However, resistance to fluoroquinolones, the second-line treatment, is increasing in M. genitalium In this study, we describe a new assay, MG+parC (beta), which simultaneously reports the detection of M. genitalium and five parC mutations that have been associated with resistance to fluoroquinolones. These mutations affect the amino acid sequence of ParC at residues S83R (A247C), S83I (G248T), D87N (G259A), D87Y (G259T), and D87H (G259C). The study tested the MG+parC (beta) assay with 202 M. genitalium-positive clinical samples from Australia (n = 141) and Spain (n = 61). Compared to Sanger sequencing, the assay performed with a kappa value of 0.985 (95% confidence interval [CI], 0.955 to 1.000), with a mutation detection sensitivity of 97.6% (95% CI, 87.4 to 99.9), and specificity of 100.0% (95% CI, 97.7 to 100.0). Fluoroquinolone resistance-associated mutations in parC targeted by the assay were more prevalent among the Australian cohort (23.4% [95% CI,16.3 to 31.8]) compared to the Spanish population (8.8% [95% CI, 2.9% to 19.3%]) (P = 0.019). The MG+parC (beta) kit is a simple and reliable method for simultaneous detection of M. genitalium and fluoroquinolone resistance-associated mutations in clinical settings. This novel diagnostic tool may extend the utility of the second line of antimicrobial therapies in M. genitalium infection.

7.
J Clin Microbiol ; 57(9)2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31243085

RESUMO

Mycoplasma genitalium is a common sexually transmitted infection with a propensity to acquire resistance to commonly used antimicrobial therapies. Bacterial load has been linked to patient symptoms and the success of treatment. In this study, we demonstrate methodology to estimate load from routine diagnostic assays using the ResistancePlus MG test (SpeeDx Pty Ltd., Australia). The method gave comparable quantitation to an M. genitalium-specific 16S rRNA quantitative PCR (qPCR; Spearman r = 0.94) for the samples analyzed (n = 499, including urine and swab types as detailed below) and was, therefore, employed to analyze typical load levels for samples in a diagnostic laboratory (total of 1,012 tests). When stratified by sample type, female urine (median, 826 genomes/ml) had the lowest load. This was significantly lower than median loads for all other sample types (male urine [6.91 × 103 genomes/ml], anal swabs [5.50 × 103], cervical swabs [8.15 × 103], endocervical swabs [3.97 × 103], and vaginal swabs [6.95 × 103]) (P < 0.0001). There were no significant differences in load estimates between the other sample types. Reproducibility of load estimates conducted on the same samples was high (r > 0.85). In conclusion, this methodology to provide load estimates for M. genitalium can be easily integrated into routine diagnostic laboratory workflow. Given the association between organism load, symptoms, and treatment success, load assessment has future diagnostic potential.

8.
Emerg Infect Dis ; 25(4): 719-727, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30882306

RESUMO

During 2016-2017, we tested asymptomatic men who have sex with men (MSM) in Melbourne, Australia, for Mycoplasma genitalium and macrolide resistance mutations in urine and anorectal swab specimens by using PCR. We compared M. genitalium detection rates for those asymptomatic men to those for MSM with proctitis and nongonococcal urethritis (NGU) over the same period. Of 1,001 asymptomatic MSM, 95 had M. genitalium; 84.2% were macrolide resistant, and 17% were co-infected with Neisseria gonorrhoeae or Chlamydia trachomatis. Rectal positivity for M. genitalium was 7.0% and urine positivity was 2.7%. M. genitalium was not more commonly detected in the rectums of MSM (n = 355, 5.6%) with symptoms of proctitis over the same period but was more commonly detected in MSM (n = 1,019, 8.1%) with NGU. M. genitalium is common and predominantly macrolide-resistant in asymptomatic MSM. M. genitalium is not associated with proctitis in this population.


Assuntos
Homossexualidade Masculina , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/microbiologia , Mycoplasma genitalium , Doenças Bacterianas Sexualmente Transmissíveis/diagnóstico , Doenças Bacterianas Sexualmente Transmissíveis/microbiologia , Antibacterianos/farmacologia , Austrália/epidemiologia , Coinfecção , Estudos Transversais , Farmacorresistência Bacteriana , Humanos , Masculino , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/transmissão , Mycoplasma genitalium/efeitos dos fármacos , Razão de Chances , Prevalência , Vigilância em Saúde Pública , Doenças Bacterianas Sexualmente Transmissíveis/epidemiologia , Doenças Bacterianas Sexualmente Transmissíveis/transmissão , Avaliação de Sintomas
9.
Clin Infect Dis ; 68(4): 554-560, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29873691

RESUMO

Background: Rising macrolide and quinolone resistance in Mycoplasma genitalium necessitate new treatment approaches. We evaluated outcomes of sequential antimicrobial therapy for M. genitalium guided by a macrolide-resistance assay. Methods: In mid-2016, Melbourne Sexual Health Centre switched from azithromycin to doxycycline (100 mg twice daily for 7 days) for nongonococcal urethritis, cervicitis, and proctitis. Cases were tested for M. genitalium and macrolide-resistance mutations (MRMs) by polymerase chain reaction. Directly after doxycycline, MRM-negative infections received 2.5 g azithromycin (1 g, then 500 mg daily for 3 days), and MRM-positive infections received sitafloxacin (100 mg twice daily for 7 days). Assessment of test of cure and reinfection risk occurred 14-90 days after the second antibiotic. Results: Of 244 evaluable M. genitalium infections (52 women, 68 heterosexual men, 124 men who have sex with men) diagnosed from 20 June 2016 to 15 May 2017, MRMs were detected in 167 (68.4% [95% confidence interval {CI}, 62.2%-74.2%]). Treatment with doxycycline decreased bacterial load by a mean 2.60 log10 (n = 56; P < .0001). Microbiologic cure occurred in 73 of 77 MRM-negative infections (94.8% [95% CI, 87.2%-98.6%]) and in 154 of 167 MRM-positive infections (92.2% [95% CI, 87.1%-95.8%]). Selection of macrolide resistance occurred in only 2 of 76 (2.6% [95% CI, .3%-9.2%]) macrolide-susceptible infections. Conclusions: In the context of high levels of antimicrobial resistance, switching from azithromycin to doxycycline for presumptive treatment of M. genitalium, followed by resistance-guided therapy, cured ≥92% of infections, with infrequent selection of macrolide resistance.

10.
BMC Microbiol ; 18(1): 184, 2018 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-30424728

RESUMO

BACKGROUND: The ProPrems trial, a multi-center, double-blind, placebo-controlled randomized trial, previously reported a 54% reduction in necrotizing enterocolitis (NEC) of Bell stage 2 or more from 4.4 to 2.0% in 1099 infants born before 32 completed weeks' gestation and weighing < 1500 g, receiving probiotic supplementation (with Bifidobacterium longum subsp. infantis BB-02, Streptococcus thermophilus TH-4 and Bifidobacterium animalis subsp. lactis BB-12). This sub-study investigated the effect of probiotic supplementation on the gut microbiota in a cohort of very preterm infants in ProPrems. RESULTS: Bifidobacterium was found in higher abundance in infants who received the probiotics (AOR 17.22; 95% CI, 3.49-84.99, p < 0.001) as compared to the placebo group, and Enterococcus was reduced in infants receiving the probiotic during the supplementation period (AOR 0.27; 95% CI, 0.09-0.82, p = 0.02). CONCLUSION: Probiotic supplementation with BB-02, TH-4 and BB-12 from soon after birth increased the abundance of Bifidobacterium in the gut microbiota of very preterm infants. Increased abundance of Bifidobacterium soon after birth may be associated with reducing the risk of NEC in very preterm infants.


Assuntos
Suplementos Nutricionais/análise , Enterocolite Necrosante/prevenção & controle , Microbioma Gastrointestinal , Lactente Extremamente Prematuro/crescimento & desenvolvimento , Probióticos/administração & dosagem , Bifidobacterium/genética , Bifidobacterium/isolamento & purificação , Bifidobacterium/efeitos da radiação , Estudos de Coortes , Método Duplo-Cego , Enterocolite Necrosante/microbiologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Streptococcus thermophilus/genética , Streptococcus thermophilus/isolamento & purificação , Streptococcus thermophilus/fisiologia
11.
Vet Microbiol ; 223: 47-50, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30173751

RESUMO

A previously-described live, attenuated vaccine (M1352, serovar Manilae, serogroup Pyrogenes) was tested in the hamster model of infection for cross-protective immunity. The vaccine elicited strong, significant cross-protection against lethal infection by strains representing four serologically distinct leptospiral serovars (Grippotyphosa, Australis, Canicola, and Autumnalis). Combined with our previously reported protection against serovars Pomona and Manilae, this work demonstrates unequivocal proof of concept for cross-protective immunity in leptospirosis.


Assuntos
Vacinas Bacterianas/imunologia , Leptospira/imunologia , Leptospirose/prevenção & controle , Animais , Cricetinae , Proteção Cruzada , Modelos Animais de Doenças , Leptospirose/microbiologia , Sorogrupo , Vacinas Atenuadas/imunologia
12.
PLoS One ; 13(1): e0190199, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29293559

RESUMO

OBJECTIVES: Recurrence following recommended treatment for bacterial vaginosis is unacceptably high. While the pathogenesis of recurrence is not well understood, recent evidence indicates re-infection from sexual partners is likely to play a role. The aim of this study was to assess the acceptability and tolerability of topical and oral antimicrobial therapy in male partners of women with bacterial vaginosis (BV), and to investigate the impact of dual-partner treatment on the vaginal and penile microbiota. METHODS: Women with symptomatic BV (Nugent Score of 4-10 and ≥3 Amsel criteria) and their regular male sexual partner were recruited from Melbourne Sexual Health Centre, Melbourne, Australia. Women received oral metronidazole 400mg twice daily (or intra-vaginal 2% clindamycin cream, if contraindicated) for 7-days. Male partners received oral metronidazole 400mg twice daily and 2% clindamycin cream topically to the penile skin twice daily for 7-days. Couples provided self-collected genital specimens and completed questionnaires at enrolment and then weekly for 4-weeks. Genital microbiota composition was determined by 16S rRNA gene sequencing. Changes in genital microbiota composition were assessed by Bray-Curtis index. Bacterial diversity was measured by the Shannon Diversity Index. RESULTS: Twenty-two couples were recruited. Sixteen couples (76%) completed all study procedures. Adherence was high; most participants took >90% of prescribed medication. Medication, and particularly topical clindamycin in males, was well tolerated. Dual-partner treatment had an immediate and sustained effect on the composition of vaginal microbiota (median Bray-Curtis score day 0 versus day 8 = 0.03 [IQR 0-0.15], day 0 vs day 28 = 0.03 [0.02-0.11]). We observed a reduction in bacterial diversity of the vaginal microbiota and a decrease in the prevalence and abundance of BV-associated bacteria following treatment. Treatment had an immediate effect on the composition of the cutaneous penile microbiota (median Bray-Curtis score day 0 vs day 8 = 0.09 [0.04-0.17]), however this was not as pronounced at day 28 (median Bray-Curtis score day 0 vs day 28 = 0.38 [0.11-0.59]). A decrease in the prevalence and abundance of BV-associated bacteria in the cutaneous penile microbiota was observed immediately following treatment at day 8. CONCLUSION: Combined oral and topical treatment of male partners of women with BV is acceptable and well tolerated. The combined acceptability and microbiological data presented in this paper supports the need for larger studies with longer follow up to characterize the sustained effect of dual partner treatment on the genital microbiota of couples and assess the impact on BV recurrence.


Assuntos
Antibacterianos/uso terapêutico , Pênis/microbiologia , Parceiros Sexuais , Vagina/microbiologia , Vaginose Bacteriana/tratamento farmacológico , Administração Oral , Administração Tópica , Adulto , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Feminino , Humanos , Masculino , Microbiota , Projetos Piloto , Pele/microbiologia
13.
Emerg Infect Dis ; 24(2): 328-335, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29350154

RESUMO

High levels of macrolide resistance and increasing fluoroquinolone resistance are found in Mycoplasma genitalium in many countries. We evaluated pristinamycin for macrolide-resistant M. genitalium in a sexual health center in Australia. Microbiologic cure was determined by M. genitalium-specific 16S PCR 14-90 days after treatment began. Of 114 persons treated with pristinamycin, infection was cured in 85 (75%). This percentage did not change when pristinamycin was given at daily doses of 2 g or 4 g or at 3 g combined with 200 mg doxycycline. In infections with higher pretreatment bacterial load, treatment was twice as likely to fail for each 1 log10 increase in bacterial load. Gastrointestinal side effects occurred in 7% of patients. Pristinamycin at maximum oral dose, or combined with doxycycline, cured 75% of macrolide-resistant M. genitalium infections. Pristinamycin is well-tolerated and remains an option where fluoroquinolones have failed or cannot be used.


Assuntos
Antibacterianos/farmacologia , Macrolídeos/farmacologia , Infecções por Mycoplasma/tratamento farmacológico , Mycoplasma genitalium/efeitos dos fármacos , Pristinamicina/uso terapêutico , Adulto , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Masculino , Infecções por Mycoplasma/microbiologia , Mycoplasma genitalium/genética
15.
Bioorg Med Chem ; 25(24): 6267-6272, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29032931

RESUMO

With multidrug resistant bacteria on the rise, novel antibiotics are becoming highly sought after. In 2008, eleven compounds were identified by high throughput screening as inhibitors of BasE, a key enzyme of the non-ribosomal peptide synthetase pathway found in Acinetobacter baumannii. Herein, we describe the preparation of four structurally similar heterocyclic lead compounds from that study, including one 1,2,5-oxadiazole. A further library of 30 analogues containing the oxadiazole moiety was then generated. All compounds were screened against Acinetobacter baumannii and their minimum inhibitory concentration data is reported, with (E)-3-(2-hydroxyphenyl)-N-(4-methyl-1,2,5-oxadiazol-3-yl)acrylamide 32 found to have an MIC of 0.5mM. This work provides the foundation for further investigation of 1,2,5-oxadizoles as novel inhibitors of A. baumannii.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Oxidiazóis/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oxidiazóis/síntese química , Oxidiazóis/química , Relação Estrutura-Atividade
16.
Emerg Infect Dis ; 23(5): 809-812, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28418319

RESUMO

Escalating resistance to azithromycin and moxifloxacin is being reported for Mycoplasma genitalium in the Asia-Pacific region. Analyzing 140 infections, we found pretreatment fluoroquinolone-resistance mutations in parC (13.6%) and gyrA (5%). ParC S83 changes were associated with moxifloxacin failure. Combined macrolide/fluoroquinolone-resistance mutations were in 8.6% of specimens, for which recommended therapies would be ineffective.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Fluoroquinolonas/farmacologia , Macrolídeos/farmacologia , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/microbiologia , Mycoplasma genitalium/efeitos dos fármacos , Austrália/epidemiologia , Feminino , Genes Bacterianos , Humanos , Masculino , Mycoplasma genitalium/genética , Polimorfismo de Nucleotídeo Único
17.
J Infect Dis ; 215(suppl_1): S52-S57, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28375520

RESUMO

Background: Acinetobacter baumannii is a pathogen of major importance in intensive care units worldwide, with the potential to cause problematic outbreaks and acquire high-level resistance to antibiotics. There is an urgent need to understand the mechanisms of A. baumannii pathogenesis for the future development of novel targeted therapies. In this study we performed an in vivo transcriptomic analysis of A. baumannii isolated from a mammalian host with bacteremia. Methods: Mice were infected with A. baumannii American Type Culture Collection 17978 using an intraperitoneal injection, and blood was extracted at 8 hours to purify bacterial RNA for RNA-Seq with an Illumina platform. Results: Approximately one-quarter of A. baumannii protein coding genes were differentially expressed in vivo compared with in vitro (false discovery rate, ≤0.001; 2-fold change) with 557 showing decreased and 329 showing increased expression. Gene groups with functions relating to translation and RNA processing were overrepresented in genes with increased expression, and those relating to chaperone and protein turnover were overrepresented in the genes with decreased expression. The most strongly up-regulated genes corresponded to the 3 recognized siderophore iron uptake clusters, reflecting the iron-restrictive environment in vivo. Metabolic changes in vivo included reduced expression of genes involved in amino acid and fatty acid transport and catabolism, indicating metabolic adaptation to a different nutritional environment. Genes encoding types I and IV pili, quorum sensing components, and proteins involved in biofilm formation all showed reduced expression. Many genes that have been reported as essential for virulence showed reduced or unchanged expression in vivo. Conclusion: This study provides the first insight into A. baumannii gene expression profiles during a life-threatening mammalian infection. Analysis of differentially regulated genes highlights numerous potential targets for the design of novel therapeutics.


Assuntos
Infecções por Acinetobacter/sangue , Acinetobacter baumannii/genética , Bacteriemia/sangue , Proteínas de Bactérias/genética , Transcriptoma , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/sangue , Farmacorresistência Bacteriana Múltipla/genética , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Camundongos , Camundongos Endogâmicos BALB C , Percepção de Quorum , RNA Bacteriano/isolamento & purificação , Análise de Sequência de RNA , Fatores de Virulência/genética
18.
PLoS One ; 12(2): e0172973, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28245231

RESUMO

Leptospirosis is one of the most widespread zoonoses in the world, and its most severe form in humans, "Weil's disease," may lead to jaundice, hemorrhage, renal failure, pulmonary hemorrhage syndrome, and sometimes,fatal multiple organ failure. Although the mechanisms underlying jaundice in leptospirosis have been gradually unraveled, the pathophysiology and distribution of leptospires during the early stage of infection are not well understood. Therefore, we investigated the hamster leptospirosis model, which is the accepted animal model of human Weil's disease, by using an in vivo imaging system to observe the whole bodies of animals infected with Leptospira interrogans and to identify the colonization and growth sites of the leptospires during the early phase of infection. Hamsters, infected subcutaneously with 104 bioluminescent leptospires, were analyzed by in vivo imaging, organ culture, and microscopy. The results showed that the luminescence from the leptospires spread through each hamster's body sequentially. The luminescence was first detected at the injection site only, and finally spread to the central abdomen, in the liver area. Additionally, the luminescence observed in the adipose tissue was the earliest detectable compared with the other organs, indicating that the leptospires colonized the adipose tissue at the early stage of leptospirosis. Adipose tissue cultures of the leptospires became positive earlier than the blood cultures. Microscopic analysis revealed that the leptospires colonized the inner walls of the blood vessels in the adipose tissue. In conclusion, this is the first study to report that adipose tissue is an important colonization site for leptospires, as demonstrated by microscopy and culture analyses of adipose tissue in the hamster model of Weil's disease.


Assuntos
Tecido Adiposo/parasitologia , Leptospira interrogans/patogenicidade , Leptospirose/patologia , Leptospirose/parasitologia , Animais , Cricetinae , Modelos Animais de Doenças , Feminino , Medições Luminescentes , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Doença de Weil/parasitologia
19.
Proc Natl Acad Sci U S A ; 113(34): 9599-604, 2016 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-27506797

RESUMO

Innate cellular immune responses are a critical first-line defense against invading bacterial pathogens. Leukocyte migration from the bloodstream to a site of infection is mediated by chemotactic factors that are often host-derived. More recently, there has been a greater appreciation of the importance of bacterial factors driving neutrophil movement during infection. Here, we describe the development of a zebrafish infection model to study Acinetobacter baumannii pathogenesis. By using isogenic A. baumannii mutants lacking expression of virulence effector proteins, we demonstrated that bacterial drivers of disease severity are conserved between zebrafish and mammals. By using transgenic zebrafish with fluorescent phagocytes, we showed that a mutation of an established A. baumannii global virulence regulator led to marked changes in neutrophil behavior involving rapid neutrophil influx to a localized site of infection, followed by prolonged neutrophil dwelling. This neutrophilic response augmented bacterial clearance and was secondary to an impaired A. baumannii phenylacetic acid catabolism pathway, which led to accumulation of phenylacetate. Purified phenylacetate was confirmed to be a neutrophil chemoattractant. These data identify a previously unknown mechanism of bacterial-guided neutrophil chemotaxis in vivo, providing insight into the role of bacterial metabolism in host innate immune evasion. Furthermore, the work provides a potentially new therapeutic paradigm of targeting a bacterial metabolic pathway to augment host innate immune responses and attenuate disease.


Assuntos
Infecções por Acinetobacter/imunologia , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Quimiotaxia/efeitos dos fármacos , Fenilacetatos/metabolismo , Fatores de Transcrição/genética , Fatores de Virulência/genética , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/patologia , Acinetobacter baumannii/imunologia , Acinetobacter baumannii/metabolismo , Acinetobacter baumannii/patogenicidade , Animais , Animais Geneticamente Modificados , Quimiotaxia/imunologia , Embrião não Mamífero , Feminino , Expressão Gênica , Imunidade Inata , Redes e Vias Metabólicas/genética , Camundongos , Camundongos Endogâmicos BALB C , Infiltração de Neutrófilos , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Neutrófilos/microbiologia , Fenilacetatos/farmacologia , Fatores de Transcrição/deficiência , Virulência , Fatores de Virulência/deficiência , Peixe-Zebra
20.
Antimicrob Agents Chemother ; 60(1): 161-7, 2016 01.
Artigo em Inglês | MEDLINE | ID: mdl-26482299

RESUMO

Multidrug-resistant (MDR) Acinetobacter baumannii is an opportunistic human pathogen that has become highly problematic in the clinical environment. Novel therapies are desperately required. To assist in identifying new therapeutic targets, the antagonistic interactions between A. baumannii and the most common human fungal pathogen, Candida albicans, were studied. We have observed that the C. albicans quorum-sensing molecule, farnesol, has cross-kingdom interactions, affecting the viability of A. baumannii. To gain an understanding of its mechanism, the transcriptional profile of A. baumannii exposed to farnesol was examined. Farnesol caused dysregulation of a large number of genes involved in cell membrane biogenesis, multidrug efflux pumps (AcrAB-like and AdeIJK-like), and A. baumannii virulence traits such as biofilm formation (csuA, csuB, and ompA) and motility (pilZ and pilH). We also observed a strong induction in genes involved in cell division (minD, minE, ftsK, ftsB, and ftsL). These transcriptional data were supported by functional assays showing that farnesol disrupts A. baumannii cell membrane integrity, alters cell morphology, and impairs virulence characteristics such as biofilm formation and twitching motility. Moreover, we showed that A. baumannii uses efflux pumps as a defense mechanism against this eukaryotic signaling molecule. Owing to its effects on membrane integrity, farnesol was tested to see if it potentiated the activity of the membrane-acting polymyxin antibiotic colistin. When coadministered, farnesol increased sensitivity to colistin for otherwise resistant strains. These data provide mechanistic understanding of the antagonistic interactions between diverse pathogens and may provide important insights into novel therapeutic strategies.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Candida albicans/patogenicidade , Farneseno Álcool/farmacologia , Regulação Bacteriana da Expressão Gênica , Transcriptoma/efeitos dos fármacos , Acinetobacter baumannii/genética , Acinetobacter baumannii/metabolismo , Antibacterianos/farmacologia , Antibiose , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Membrana Celular/efeitos dos fármacos , Colistina/farmacologia , Sinergismo Farmacológico , Farneseno Álcool/metabolismo , Genes MDR , Percepção de Quorum
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