Repurposing Salicylamide for Combating Multidrug-Resistant Neisseria gonorrhoeae

ABSTRACT 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 to 32 μg/ml) with low frequency of resistance <2.4 × 10−9. Interestingly, salicylamide did not inhibit growth of bacterial species in the vaginal microflora involved in defense against gonococcal infections, such as Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus johnsonii, and Lactobacillus crispatus. A time-kill assay revealed that salicylamide is a rapidly bactericidal drug, as it eradicated a high inoculum of N. gonorrhoeae within 10 h. 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 proinflammatory cytokine interleukin 8 (IL-8) from endocervical cells infected with N. gonorrhoeae. A checkerboard assay revealed that salicylamide exhibited a synergistic interaction with tetracycline and additive relationships with azithromycin, 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 antigonorrheal activity. In conclusion, this study identified salicylamide as a promising candidate for further investigation as a novel treatment option for multidrug-resistant gonorrhea.

Download Full-text

Emergence of Multidrug-Resistant Campylobacter Species Isolates with a Horizontally Acquired rRNA Methylase

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03039-14 ◽

2014 ◽

Vol 58 (9) ◽

pp. 5405-5412 ◽

Cited By ~ 67

Author(s):

Yang Wang ◽

Maojun Zhang ◽

Fengru Deng ◽

Zhangqi Shen ◽

Congming Wu ◽

...

Keyword(s):

Molecular Typing ◽

Multidrug Resistant ◽

Genomic Islands ◽

Campylobacter Coli ◽

Antibiotic Resistant ◽

Content Type ◽

Drug Of Choice ◽

Methylase Gene ◽

High Level ◽

Level Resistance

ABSTRACTAntibiotic-resistantCampylobacterconstitutes a serious threat to public health, and resistance to macrolides is of particular concern, as this class of antibiotics is the drug of choice for clinical therapy of campylobacteriosis. Very recently, a horizontally transferrable macrolide resistance mediated by the rRNA methylase geneerm(B) was reported in aCampylobacter coliisolate, but little is known about the dissemination oferm(B) amongCampylobacterisolates and the association oferm(B)-carrying isolates with clinical disease. To address this question and facilitate the control of antibiotic-resistantCampylobacter, we determined the distribution oferm(B) in 1,554C. coliandCampylobacter jejuniisolates derived from food-producing animals and clinically confirmed human diarrheal cases. The results revealed that 58 of the examined isolates harborederm(B) and exhibited high-level resistance to macrolides, and most were recent isolates, derived in 2011-2012. In addition, theerm(B)-positive isolates were all resistant to fluoroquinolones, another clinically important antibiotic used for treating campylobacteriosis. Theerm(B) gene is found to be associated with chromosomal multidrug resistance genomic islands (MDRGIs) of Gram-positive origin or with plasmids of various sizes. All MDRGIs were transferrable to macrolide-susceptibleC. jejuniby natural transformation under laboratory conditions. Molecular typing of theerm(B)-carrying isolates by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) identified diverse genotypes and outbreak-associated diarrheal isolates. Molecular typing also suggested zoonotic transmission oferm(B)-positiveCampylobacter. These findings reveal an emerging and alarming trend of dissemination oferm(B) and MDRGIs inCampylobacterand underscore the need for heightened efforts to control their further spread.

Download Full-text

Prevalence of antibiotic-resistant Salmonella in retail organic chicken

British Food Journal ◽

10.1108/bfj-10-2019-0790 ◽

2020 ◽

Vol 122 (4) ◽

pp. 1238-1251

Author(s):

Husnu Sahan Guran ◽

Resat Ciftci ◽

Nafia Canan Gursoy ◽

Tuncer Ozekinci ◽

Walid Q. Alali

Keyword(s):

Health Risk ◽

Genetic Relatedness ◽

Multidrug Resistant ◽

Class I ◽

Online Retailer ◽

Potential Health ◽

Antibiotic Resistant ◽

Content Type ◽

Drug Of Choice ◽

Southeast Anatolia

PurposeThe objective of this study was to determine Salmonella prevalence, antimicrobial-resistant phenotypes, and their genetic relatedness in frozen organic chicken collected at retail level in Turkey.Design/methodology/approachRetail packs (n = 348) of cut-up chicken parts (breast, leg quarter and drumstick) and whole chicken carcasses were purchased from a central hypermarket in Diyarbakir (Southeast Anatolia Region in Turkey) and from a large online retailer in Turkey. The retail packs were paired by part type, brand, production date, and sell-by date. The chicken samples were analyzed for the presence of Salmonella spp., and then isolates were screened for antibiotic susceptibility, class I integron, and genetic similarity.FindingsSalmonella prevalence in retail frozen organic chicken samples was 6.3 percent; however, the prevalence by parts, leg quarter, drumstick, breast, and whole chicken was 2.1 percent, 10.4 percent, 10.4 percent, and 0 percent, respectively. Salmonella prevalence was significantly higher in samples obtained from the hypermarket (9.2 percent) compared to online retailer (3.8 percent). All the isolates were serotype Infantis, genetically similar (highly clonal), and 68.2 percent harbored class I integron. All isolates were resistant to ciprofloxacin (drug of choice to treat salmonellosis in human), and 86.3 percent of the isolates were multidrug-resistant.Originality/valueSalmonella prevalence in organic chicken meat, regardless of the retail market source in Turkey, may pose a health risk to consumers especially with the high prevalence of multi-drug resistant phenotypes. Findings inform researchers and the public about the safety of organically produced chicken and the potential health risk to consumers.

Download Full-text

Antiviral Resistance and Phage Counter Adaptation to Antibiotic-Resistant Extraintestinal Pathogenic Escherichia coli

mBio ◽

10.1128/mbio.00211-21 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Keiko C. Salazar ◽

Li Ma ◽

Sabrina I. Green ◽

Jacob J. Zulk ◽

Barbara W. Trautner ◽

...

Keyword(s):

Escherichia Coli ◽

Bacterial Resistance ◽

Phage Therapy ◽

Systemic Infection ◽

The United States ◽

Multidrug Resistant ◽

Antibiotic Resistant ◽

Content Type ◽

E Coli ◽

Systemic Infections

ABSTRACT Extraintestinal pathogenic Escherichia coli (ExPEC), often multidrug resistant (MDR), is a leading cause of urinary tract and systemic infections. The crisis of emergent MDR pathogens has led some to propose bacteriophages as a therapeutic. However, bacterial resistance to phage is a concerning issue that threatens to undermine phage therapy. Here, we demonstrate that E. coli sequence type 131, a circulating pandemic strain of ExPEC, rapidly develops resistance to a well-studied and therapeutically active phage (ϕHP3). Whole-genome sequencing of the resisters revealed truncations in genes involved in lipopolysaccharide (LPS) biosynthesis, the outer membrane transporter ompA, or both, implicating them as phage receptors. We found ExPEC resistance to phage is associated with a loss of fitness in host microenvironments and attenuation in a murine model of systemic infection. Furthermore, we constructed a novel phage-bacterium bioreactor to generate an evolved phage isolate with restored infectivity to all LPS-truncated ExPEC resisters. This study suggests that although the resistance of pandemic E. coli to phage is frequent, it is associated with attenuation of virulence and susceptibility to new phage variants that arise by directed evolution. IMPORTANCE In response to the rising crisis of antimicrobial resistance, bacteriophage (phage) therapy has gained traction. In the United States, there have been over 10 cases of largely successful compassionate-use phage therapy to date. The resilience of pathogens allowing their broad antibiotic resistance means we must also consider resistance to therapeutic phages. This work fills gaps in knowledge regarding development of phage resisters in a model of infection and finds critical fitness losses in those resisters. We also found that the phage was able to rapidly readapt to these resisters.

Download Full-text

Repurposing Fenamic Acid Drugs To Combat Multidrug-Resistant Neisseria gonorrhoeae

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02206-19 ◽

2020 ◽

Vol 64 (7) ◽

Author(s):

Young Jin Seong ◽

Marwa Alhashimi ◽

Abdelrahman Mayhoub ◽

Haroon Mohammad ◽

Mohamed N. Seleem

Keyword(s):

Neisseria Gonorrhoeae ◽

Anthranilic Acid ◽

Limit Of Detection ◽

Low Frequency ◽

Drug Repurposing ◽

Multidrug Resistant ◽

Tolfenamic Acid ◽

New Drugs ◽

Flufenamic Acid ◽

Content Type

ABSTRACT The rise of extensively drug-resistant 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 require more time than can be spared until gonococcal infections become difficult 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 antigonococcal activity, inhibiting 50% of the strains (MIC50) from 4 to 16 μg/ml. Furthermore, tolfenamic acid showed 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 h and exhibited a low frequency of resistance. Interestingly, the fenamic acids did not inhibit the 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 proinflammatory 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 antigonorrheal scaffold. This SAR study will pave the road to repositioning more potent fenamic acids analogues against N. gonorrhoeae.

Download Full-text

Diagnostic tests for detecting Chlamydia trachomatis and Neisseria gonorrhoeae in rectal and pharyngeal specimens

Journal of Clinical Microbiology ◽

10.1128/jcm.00211-21 ◽

2021 ◽

Author(s):

Paul C. Adamson ◽

Jeffrey D. Klausner

Keyword(s):

Chlamydia Trachomatis ◽

Neisseria Gonorrhoeae ◽

Bacterial Infections ◽

Point Of Care ◽

High Sensitivity ◽

Population Level ◽

The United States ◽

Nucleic Acid Amplification ◽

Point Of Care Test ◽

Control And Prevention

Chlamydia trachomatis and Neisseria gonorrhoeae are two of the most often reported bacterial infections in the United States. The rectum and oropharynx are important anatomic sites of infection and can contribute to ongoing transmission. Nucleic acid amplification tests (NAATs) are the mainstays for the detection of C. trachomatis and N. gonorrhoeae infections owing to their high sensitivity and specificity. Several NAATs have been evaluated for testing in rectal and pharyngeal infections. A few assays recently received clearance by the Food and Drug Administration, including one point-of-care test. Those assays can be used for testing in symptomatic individuals, as well as for asymptomatic screening in certain patient populations. Routine screening for C. trachomatis in pharyngeal specimens is not recommended by the Centers for Disease Control and Prevention, though is often performed due to the use of multiplex assays. While expanding the types of settings for screening and using self-collected rectal and pharyngeal specimens can help to increase access and uptake of testing, additional research is needed to determine the potential benefits and costs associated with increased screening for rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections on a population level.

Download Full-text

Corrected Genome Sequence of Acinetobacter baumannii Strain AB0057, an Antibiotic-Resistant Isolate from Lineage 1 of Global Clone 1

Genome Announcements ◽

10.1128/genomea.00836-17 ◽

2017 ◽

Vol 5 (35) ◽

Cited By ~ 7

Author(s):

Mohammad Hamidian ◽

Pratap Venepally ◽

Ruth M. Hall ◽

Mark D. Adams

Keyword(s):

United States ◽

Acinetobacter Baumannii ◽

Genome Sequence ◽

The United States ◽

Targeted Sequencing ◽

Resistant Isolate ◽

Illumina Hiseq ◽

Antibiotic Resistant ◽

Content Type ◽

Pcr Products

ABSTRACT Extensively antibiotic-resistant Acinetobacter baumannii isolate AB0057 recovered in the United States in 2004 was one of the first global clone 1 isolates to be completely sequenced. Here, the complete 4.05-Mb genome sequence (chromosome and one plasmid) has been revised using Illumina HiSeq data and targeted sequencing of PCR products.

Download Full-text

Disseminated Gonococcal Infections in Patients Receiving Eculizumab: A Case Series

Clinical Infectious Diseases ◽

10.1093/cid/ciy958 ◽

2018 ◽

Vol 69 (4) ◽

pp. 596-600 ◽

Cited By ~ 15

Author(s):

Page E Crew ◽

Winston E Abara ◽

Lynda McCulley ◽

Peter E Waldron ◽

Robert D Kirkcaldy ◽

...

Keyword(s):

Neisseria Gonorrhoeae ◽

Medical Literature ◽

Treatment Guidelines ◽

Antimicrobial Prophylaxis ◽

Case Series ◽

The United States ◽

Underlying Disease ◽

Sexually Transmitted ◽

Control And Prevention ◽

Terminal Complement

Abstract Background Gonorrhea is the second most commonly reported notifiable condition in the United States. Infrequently, Neisseria gonorrhoeae can cause disseminated gonococcal infection (DGI). Eculizumab, a monoclonal antibody, inhibits terminal complement activation, which impairs the ability of the immune system to respond effectively to Neisseria infections. This series describes cases of N. gonorrhoeae infection among patients receiving eculizumab. Methods Pre- and postmarketing safety reports of N. gonorrhoeae infection in patients receiving eculizumab worldwide were obtained from US Food and Drug Administration safety databases and the medical literature, including reports from the start of pivotal clinical trials in 2004 through 31 December 2017. Included patients had at least 1 eculizumab dose within the 3 months prior to N. gonorrhoeae infection. Results Nine cases of N. gonorrhoeae infection were identified; 8 were classified as disseminated (89%). Of the disseminated cases, 8 patients required hospitalization, 7 had positive blood cultures, and 2 required vasopressor support. One patient required mechanical ventilation. Neisseria gonorrhoeae may have contributed to complications prior to death in 1 patient; however, the fatality was attributed to underlying disease per the reporter. Conclusions Patients receiving eculizumab may be at higher risk for DGI than the general population. Prescribers are encouraged to educate patients receiving eculizumab on their risk for serious gonococcal infections and perform screening for sexually transmitted diseases (STDs) per the Centers for Disease Control and Prevention STD treatment guidelines or in suspected cases. If antimicrobial prophylaxis is used during eculizumab therapy, prescribers should consider trends in gonococcal antimicrobial susceptibility due to emerging resistance concerns.

Download Full-text

The Lst Sialyltransferase of Neisseria gonorrhoeae Can Transfer Keto-Deoxyoctanoate as the Terminal Sugar of Lipooligosaccharide: a Glyco-Achilles Heel That Provides a New Strategy for Vaccines to Prevent Gonorrhea

mBio ◽

10.1128/mbio.03666-20 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Freda E.-C. Jen ◽

Margaret R. Ketterer ◽

Evgeny A. Semchenko ◽

Christopher J. Day ◽

Kate L. Seib ◽

...

Keyword(s):

Monoclonal Antibody ◽

Neisseria Gonorrhoeae ◽

Phase Variation ◽

Multidrug Resistant ◽

Content Type ◽

Acetylneuraminic Acid ◽

New Strategy ◽

Opsonophagocytic Killing ◽

Further Development

ABSTRACT The lipooligosaccharide (LOS) of Neisseria gonorrhoeae plays key roles in pathogenesis and is composed of multiple possible glycoforms. These glycoforms are generated by the process of phase variation and by differences in the glycosyltransferase gene content of particular strains. LOS glycoforms of N. gonorrhoeae can be terminated with an N-acetylneuraminic acid (Neu5Ac), which imparts resistance to the bactericidal activity of serum. However, N. gonorrhoeae cannot synthesize the CMP-Neu5Ac required for LOS biosynthesis and must acquire it from the host. In contrast, Neisseria meningitidis can synthesize endogenous CMP-Neu5Ac, the donor molecule for Neu5Ac, which is a component of some meningococcal capsule structures. Both species have an almost identical LOS sialyltransferase, Lst, that transfers Neu5Ac from CMP-Neu5Ac to the terminus of LOS. Lst is homologous to the LsgB sialyltransferase of nontypeable Haemophilus influenzae (NTHi). Studies in NTHi have demonstrated that LsgB can transfer keto-deoxyoctanoate (KDO) from CMP-KDO to the terminus of LOS in place of Neu5Ac. Here, we show that Lst can also transfer KDO to LOS in place of Neu5Ac in both N. gonorrhoeae and N. meningitidis. Consistent with access to the pool of CMP-KDO in the cytoplasm, we present data indicating that Lst is localized in the cytoplasm. Lst has previously been reported to be localized on the outer membrane. We also demonstrate that KDO is expressed as a terminal LOS structure in vivo in samples from infected women and further show that the anti-KDO monoclonal antibody 6E4 can mediate opsonophagocytic killing of N. gonorrhoeae. Taken together, these studies indicate that KDO expressed on gonococcal LOS represents a new antigen for the development of vaccines against gonorrhea. IMPORTANCE The emergence of multidrug-resistant N. gonorrhoeae strains that are resistant to available antimicrobials is a current health emergency, and no vaccine is available to prevent gonococcal infection. Lipooligosaccharide (LOS) is one of the major virulence factors of N. gonorrhoeae. The sialic acid N-acetylneuraminic acid (Neu5Ac) is present as the terminal glycan on LOS in N. gonorrhoeae. In this study, we made an unexpected discovery that KDO can be incorporated as the terminal glycan on LOS of N. gonorrhoeae by the alpha-2,3-sialyltransferase Lst. We showed that N. gonorrhoeae express KDO on LOS in vivo and that the KDO-specific monoclonal antibody 6E4 can direct opsonophagocytic killing of N. gonorrhoeae. These data support further development of KDO-LOS structures as vaccine antigens for the prevention of infection by N. gonorrhoeae.

Download Full-text

Emergence of a Competence-Reducing Filamentous Phage from the Genome of Acinetobacter baylyi ADP1

Journal of Bacteriology ◽

10.1128/jb.00424-16 ◽

2016 ◽

Vol 198 (23) ◽

pp. 3209-3219 ◽

Cited By ~ 12

Author(s):

Brian A. Renda ◽

Cindy Chan ◽

Kristin N. Parent ◽

Jeffrey E. Barrick

Keyword(s):

Acinetobacter Baumannii ◽

Vibrio Cholerae ◽

Bacterial Species ◽

Normal Growth ◽

Multidrug Resistant ◽

Filamentous Phage ◽

Acinetobacter Baylyi ◽

Laboratory Evolution ◽

Content Type ◽

Evolution Experiment

ABSTRACTBacterial genomes commonly contain prophage sequences as a result of past infections with lysogenic phages. Many of these integrated viral sequences are believed to be cryptic, but prophage genes are sometimes coopted by the host, and some prophages may be reactivated to form infectious particles when cells are stressed or mutate. We found that a previously uncharacterized filamentous phage emerged from the genome ofAcinetobacter baylyiADP1 during a laboratory evolution experiment. This phage has a genetic organization similar to that of theVibrio choleraeCTXϕ phage. The emergence of the ADP1 phage was associated with the evolution of reduced transformability in our experimental populations, so we named it thecompetence-reducingacinetobacter phage (CRAϕ). Knocking out ADP1 genes required for competence leads to resistance to CRAϕ infection. Although filamentous bacteriophages are known to target type IV pili, this is the first report of a phage that apparently uses a competence pilus as a receptor.A. baylyimay be especially susceptible to this route of infection because every cell is competent during normal growth, whereas competence is induced only under certain environmental conditions or in a subpopulation of cells in other bacterial species. It is possible that CRAϕ-like phages restrict horizontal gene transfer in nature by inhibiting the growth of naturally transformable strains. We also found that prophages with homology to CRAϕ exist in several strains ofAcinetobacter baumannii. These CRAϕ-likeA. baumanniiprophages encode toxins similar to CTXϕ that might contribute to the virulence of this opportunistic multidrug-resistant pathogen.IMPORTANCEWe observed the emergence of a novel filamentous phage (CRAϕ) from the genome ofAcinetobacter baylyiADP1 during a long-term laboratory evolution experiment. CRAϕ is the first bacteriophage reported to require the molecular machinery involved in the uptake of environmental DNA for infection. Reactivation and evolution of CRAϕ reduced the potential for horizontal transfer of genes via natural transformation in our experiment. Risk of infection by similar phages may limit the expression and maintenance of bacterial competence in nature. The closest studied relative of CRAϕ is theVibrio choleraeCTXϕ phage. Variants of CRAϕ are found in the genomes ofAcinetobacter baumanniistrains, and it is possible that phage-encoded toxins contribute to the virulence of this opportunistic multidrug-resistant pathogen.

Download Full-text