Figure - available from: Antimicrobial Agents and Chemotherapy
This content is subject to copyright. Terms and conditions apply.
Growth of Neisseria species are inhibited by DTZ. N. gonorrhoeae strain MS11 (A to C) and N. lactamica strain 49142 (D) were grown in an automatic plate reader for 14 to 16 h with DTZ of indicated concentrations either added 2 h into growth (mid-log-phase) (A and D), added 4.5 h into growth (late log phase) (B), or present throughout growth (C). Dotted vertical line indicates time of treatment, vehicle is 30% DMSO. All conditions were assessed in triplicate technical replicate wells, and each experiment was repeated a minimum of three times. Error bars represent means ± standard deviations (SD) from three replicate wells of a single representative experiment.
Source publication
The Gram-negative human pathogen Neisseria gonorrhoeae has progressively developed resistance to antibiotic monotherapies, and recent failures of dual-drug therapy have heightened concerns that strains resistant to all available antibiotics will begin circulating globally. Targeting bacterial cell wall assembly has historically been effective at tr...
Citations
... Effects on commensal bacteria. One of the disadvantages of the anti-gonococcal standard of care therapeutics is that they inhibit growth of both gonococci and commensal bacteria 35 . The vaginal microbiota are the primary defense line against N. gonorrhoeae infection. ...
Drug-resistant Neisseria gonorrhoeae represents a major threat to public health; without new effective antibiotics, untreatable gonococcal infections loom as a real possibility. In a previous drug-repurposing study, we reported that salicylic acid had good potency against azithromycin-resistant N. gonorrhoeae. We now report that the anti-gonococcal activity in this scaffold is easily lost by inopportune substitution, but that select substituted naphthyl analogs (3b, 3o and 3p) have superior activity to salicylic acid itself. Furthermore, these compounds retained potency against multiple ceftriaxone- and azithromycin-resistant strains, exhibited rapid bactericidal activity against N. gonorrhoeae, and showed high tolerability to mammalian cells (CC50 > 128 µg/mL). Promisingly, these compounds also show very weak growth inhibition of commensal vaginal bacteria.
... One of the disadvantages of the anti-gonococcal standard of care therapeutics is that they inhibit growth of both gonococci and commensal bacteria. 32 The vaginal microbiota are the primary defense line against N. gonorrhoeae infection. They compete with N. gonorrhoeae for adhesion to the genitourinary tract in addition to creating an acidic environment that prevents gonococcal colonization. ...
Drug-resistant Neisseria gonorrhoeae represents a major threat to public health; without new effective antibiotics, untreatable gonococcal infections loom as a real possibility. In a previous drug-repurposing study, we reported that salicylic acid had good potency against azithromycin-resistant N. gonorrhoeae . We now report that the anti-gonococcal activity in this scaffold is easily lost by inopportune substitution, but that select substituted naphthyl analogs ( 3b , o , p ) have superior activity to salicylic acid itself. Promisingly, these compounds also show very weak growth inhibition of commensal vaginal bacteria.
... In particular, probiotic therapy has bacterial interfering and immunomodulatory properties with potential medical benefits for treating and preventing various infections involving mucosal surfaces (Alvarez-Olmos and Oberhelman, 2001). Accordingly, there are many probiotic studies on pathogen infections such as Clostridium difficile (Biller et al., 1995), carbapenem-resistant Enterobacteriaceae (CRE) (Chen et al., 2019), Neisseria gonorrhoeae (Lenz et al., 2018), MDR Acinetobacter (Asahara et al., 2016), Campylobacter (Bhatia et al., 1989), Candida (Strus et al., 2005), extendedspectrum β-lactamase-producing Enterobacteriaceae (ESBLs) (Dey et al., 2019), vancomycin-resistant Enterococcus (VRE) (Crouzet et al., 2018), MDR Pseudomonas aeruginosa (Machairas et al., 2015), Salmonella (De Keersmaecker et al., 2006), Shigella (Nader de Macías et al., 1992), methicillin-resistant Staphylococcus aureus (MRSA) (Karska-Wysocki et al., 2010), Streptococcus pneumoniae (Racedo et al., 2006), and Streptococcus (Ho et al., 2016). As described above, many studies have suggested preventive and therapeutic effects of probiotics on infectious diseases. ...
Tuberculosis, an infectious disease, is caused by Mycobacterium tuberculosis. It remains a significant public health issue around the globe, causing about 1.8 million deaths every year. Drug-resistant M. tuberculosis, including multi-drug-resistant (MDR), extremely-drug-resistant (XDR), and totally drug-resistant (TDR) M. tuberculosis, continues to be a threat to public health. In the case of antibiotic-resistant tuberculosis, the treatment effect of conventional antibiotics is low. Side effects caused by high doses over a long period are causing severe problems. To overcome these problems, there is an urgent need to develop a new anti-tuberculosis drug that is different from the existing compound-based antibiotics. Probiotics are defined as live microorganisms conferring health benefits. They can be potential therapeutic agents in this context as the effectiveness of probiotics against different infectious diseases has been well established. Here, we report that Lactobacillus crispatus PMC201 shows a promising effect on tuberculosis isolated from vaginal fluids of healthy Korean women. Lactobacillus crispatus PMC201 reduced M. tuberculosis H37Rv under co-culture conditions in broth and reduced M. tuberculosis H37Rv and XDR M. tuberculosis in macrophages. Lactobacillus crispatus PMC201 was not toxic to a guinea pig model and did not induce dysbiosis in a human intestinal microbial ecosystem simulator. Taken together, these results indicate that L. crispatus PMC201 can be a promising alternative drug candidate in the current tuberculosis drug regime. Further study is warranted to assess the in vivo efficacy and confirm the mode of action of L. crispatus PMC201.
... Given the promising in vitro results for the three fenamic acids against N. gonorrhoeae, we strove to investigate if N. gonorrhoeae is able to develop resistance rapidly to these drugs. We utilized a single-step resistance assay to determine the frequency of spontaneous mutation to each fenamic acid tested against three different clinical N. gonorrhoeae strains, as previously described (20). No mutants were isolated when N. gonorrhoeae was exposed to either tolfenamic acid or flufenamic acid at a concentration of 10ϫ MIC, resulting in a low frequency of mutation of Ͻ2.4 ϫ 10 Ϫ10 (Tables 6 and 7). ...
... Cytokine production in infected endocervical cells. To investigate whether fenamic acids have any anti-inflammatory activity on cytokine production, IL-8, IL-6, and IL- (key cytokines that are associated with gonococcal infection) were detected in the supernatants of N. gonorrhoeae-infected human endocervical cells that were exposed to either meclofenamic acid, flufenamic acid, tolfenamic acid, or ceftriaxone, as described in a previous study (20). Briefly, endocervical cells were infected with N. gonorrhoeae strain 194 for 2 h, followed by treatment with 0.5ϫ MIC of each fenamic acid or ceftriaxone (in quadruplicates) for 8 h at 37°C with 5% CO 2 . ...
The rise of extensive and multidrug-resistant strains of Neisseria gonorrhoeae has occurred in parallel with the increasing demand for new drugs. However, the current methods of drug discovery are burdened with rigorous assessments and requires more time than can be spared until gonococcal infections become hard to control. To address this urgency, we utilized a drug repurposing strategy and identified three clinically-approved anthranilic acid drugs (tolfenamic acid, flufenamic acid, and meclofenamic acid) with potent anti-gonococcal activity, inhibiting 50% of the strains (MIC 50 ) from 4 to 16 μg/mL. Furthermore, tolfenamic acid showed an indifferent activity with antibiotics of choice for gonococcal infections, azithromycin and ceftriaxone, in checkerboard assays with a fractional inhibitory concentration index ranging from 0.75 to 1.5. Fenamic acids reduced a high inoculum of N. gonorrhoeae below the limit of detection within 12 hours and exhibited a low frequency of resistance. Interestingly, the fenamic acids did not inhibit growth of commensal Lactobacillus spp. that comprise the healthy female genital microbiota. Fenamic acids were also superior to ceftriaxone in reducing the burden of intracellular N. gonorrhoeae within infected endocervical cells by 99%. Furthermore, all three fenamic acids significantly reduced the expression of the porinflammatory cytokines by infected endocervical cells. Finally, fenamic acids and other structurally-related anthranilic acid derivatives were evaluated to ascertain a more in-depth structure activity relationship (SAR) that revealed N -phenylanthranilic acid as a novel anti-gonorrheal scaffold. This SAR study will pave the road to reposition more potent fenamic acids analogues against N. gonorrhoeae .
... To investigate the anti-inflammatory activity of the gold compounds, IL-8, a pro-inflammatory cytokine, was detected in the supernatants of N. gonorrhoeae infected End1/E6E7 -human endocervix cells (ATCC CRL-2615) exposed to either the gold-containing drugs or ceftriaxone, as previously described 42,48 . In brief, N. gonorrhoeae strain 194 was allowed to infect the endocervical cells for two hours at 37°C with 5% CO 2 before initiating treatment with 0.5 × MIC of ceftriaxone, auranofin, sodium aurothiomalate, or aurothioglucose (tested in triplicates) and left for four hours. ...
Neisseria gonorrhoeae represents an urgent public health threat due to the rapid emergence of resistance to current antibiotics and the limited number of anti-gonococcal agents currently in clinical trials. This study utilized a drug repositioning strategy to investigate FDA-approved gold-containing drugs against N. gonorrhoeae. Auranofin, sodium aurothiomalate and aurothioglucose inhibited 48 clinical isolates of N. gonorrhoeae including multidrug-resistant strains at a concentration as low as 0.03 µg/mL. A time-kill assay revealed that auranofin exhibited rapid bactericidal activity against N. gonorrhoeae. Moreover, both sodium aurothiomalate and aurothioglucose did not inhibit growth of vaginal protective commensal lactobacilli. Auranofin, in combination with azithromycin, ceftriaxone, cefixime or tetracycline showed an additive effect against four N. gonorrhoeae strains, suggesting the possibility of using auranofin in dual therapy. Moreover, auranofin reduced the burden of intracellular N. gonorrhoeae by over 99% outperforming the drug of choice ceftriaxone. Auranofin was found superior to ceftriaxone in reducing the secretion of the pro-inflammatory cytokine IL-8 by endocervical cells infected with N. gonorrhoeae. Furthermore, auranofin exhibited a prolonged post-antibiotic effect over 10 h, as well as inability to generate resistant mutants. Overall, the current study suggests that repurposing gold-containing drugs, like auranofin, for treatment of gonorrhea warrants further investigation.
... Lactobacilli are Gram-positive bacteria, in contrast to N. gonorrhoeae. One of the disadvantages of the first-line drugs used to treat N. gonorrhoeae infections is that they are nonspecific and inhibit growth of both gonococci and commensal bacteria indiscriminately (35). In contrast to the current first-line treatments, which inhibited both N. gonorrhoeae and Lactobacillus species equally (MIC values ranged from 1 to 4 g/ml), salicylamide did not inhibit growth of Lactobacillus strains tested at concentrations up to 256 g/ml. ...
... To investigate the anti-inflammatory activity of salicylamide, the proinflammatory cytokine IL-8 was detected in supernatants of N. gonorrhoeae-infected human endocervical cells exposed to either salicylamide or ceftriaxone, as described in a previous study (35). Briefly, cells were infected with N. gonorrhoeae strain 194 for 2 h followed by treatment with 0.5ϫ MIC of ceftriaxone or salicylamide (in triplicates) for 4 h. ...
The U.S. Centers for Disease Control and Prevention (CDC) lists Neisseria gonorrhoeae as one of the most urgent antibiotic-resistant threats in the United States. This is due to the emergence of clinical isolates that have developed resistance to nearly every antibiotic used to treat gonorrhea and highlights the critical need to find new therapeutics. The present study discovered salicylamide, an analgesic and antipyretic drug, has antibacterial activity against 40 different antibiotic-resistant strains of N. gonorrhoeae (MIC 8-32 μg/ml) with low frequency of resistance <2.4x10 ⁻⁹ . Interestingly, salicylamide did not inhibit growth of bacterial species in the vaginal microflora involved in defense against gonococcal infections, such as Lactobacillus gasseri, L. jensenii, L. johnsonii, and L. crispatus . A time-kill assay revealed that salicylamide is a rapidly bactericidal drug as it eradicated a high inoculum of N. gonorrhoeae within 10 hours. Salicylamide was superior to the drug of choice, ceftriaxone, in reducing the burden of intracellular N. gonorrhoeae by 97% in infected endocervical cells. Furthermore, salicylamide outperformed ceftriaxone in reducing expression of the pro-inflammatory cytokine IL-8 from endocervical cells infected with N. gonorrhoeae . A checkerboard assay revealed that salicylamide exhibited a synergistic interaction with tetracycline and an additive relationship with azithromycin and ciprofloxacin, and ceftriaxone. A more in-depth investigation of the structure-activity-relationship of derivatives of salicylamide revealed the amide and hydroxyl groups are important for anti-gonorrheal activity. In conclusion, this study identified salicylamide as a promising candidate for further investigation as a novel treatment option for multidrug-resistant gonorrhea.
