<i>Neisseria gonorrhoeae</i>Strain with Reduced Susceptibilities to Extended-Spectrum Cephalosporins

Nguyen, Duylinh; Gose, Severin; Castro, Lina; Chung, Kathleen; Bernstein, Kyle T.; Samuel, Micheal; Bauer, Heidi M.; Pandori, Mark

doi:10.3201/eid2007.131396

Cited by 16 publications

(13 citation statements)

References 14 publications

(17 reference statements)

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“…gonorrhoeae was a major cause for concern in the US and abroad, and a recent study has described cephalosporin-resistant N . gonorrhoeae in the United States [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women

et al. 2015

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Gonorrhea is a highly prevalent disease resulting in significant morbidity worldwide, with an estimated 106 cases reported annually. Neisseria gonorrhoeae, the causative agent of gonorrhea, colonizes and infects the human genital tract and often evades host immune mechanisms until successful antibiotic treatment is used. The alarming increase in antibiotic-resistant strains of N. gonorrhoeae, the often asymptomatic nature of this disease in women and the lack of a vaccine directed at crucial virulence determinants have prompted us to perform transcriptome analysis to understand gonococcal gene expression patterns during natural infection. We sequenced RNA extracted from cervico-vaginal lavage samples collected from women recently exposed to infected male partners and determined the complete N. gonorrhoeae transcriptome during infection of the lower genital tract in women. On average, 3.19% of total RNA isolated from female samples aligned to the N. gonorrhoeae NCCP11945 genome and 1750 gonococcal ORFs (65% of all protein-coding genes) were transcribed. High expression in vivo was observed in genes encoding antimicrobial efflux pumps, iron response, phage production, pilin structure, outer membrane structures and hypothetical proteins. A parallel analysis was performed using the same strains grown in vitro in a chemically defined media (CDM). A total of 140 genes were increased in expression during natural infection compared to growth in CDM, and 165 genes were decreased in expression. Large differences were found in gene expression profiles under each condition, particularly with genes involved in DNA and RNA processing, iron, transposase, pilin and lipoproteins. We specifically interrogated genes encoding DNA binding regulators and iron-scavenging proteins, and identified increased expression of several iron-regulated genes, including tbpAB and fbpAB, during infection in women as compared to growth in vitro, suggesting that during infection of the genital tract in women, the gonococcus is exposed to an iron deplete environment. Collectively, we demonstrate that a large portion of the gonococcal genome is expressed and regulated during mucosal infection including genes involved in regulatory functions and iron scavenging.

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“…gonorrhoeae was a major cause for concern in the US and abroad, and a recent study has described cephalosporin-resistant N . gonorrhoeae in the United States [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women

et al. 2015

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“…Asymptomatic infection in women can be concerning, since these women do not seek treatment, which results in untreated gonococcal infection that can lead to several serious complications, including infertility and ectopic pregnancy (5,6) as well as the possibility of further spreading the disease, a public health concern. While the majority of gonococcal infections are easily treated with antibiotic intervention, strains of N. gonorrhoeae resistant to several of the antibiotics commonly used to treat this infection have begun to emerge worldwide (7)(8)(9)(10)(11). N. gonorrhoeae remains a significant STI worldwide, and new strategies are needed to combat this infection.…”

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confidence: 99%

Global Network Analysis of Neisseria gonorrhoeae Identifies Coordination between Pathways, Processes, and Regulators Expressed during Human Infection

et al. 2020

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Neisseria gonorrhoeae is a Gram-negative diplococcus that is responsible for the sexually transmitted infection gonorrhea, a high-morbidity disease in the United States and worldwide. Over the past several years, N. gonorrhoeae strains resistant to antibiotics used to treat this infection have begun to emerge across the globe. Thus, new treatment strategies are needed to combat this organism. Here, we utilized N. gonorrhoeae transcriptomic data sets, including those obtained from natural infection of the human genital tract, to infer the first global gene coexpression network of this pathogen. Interrogation of this network revealed genes central to the network that are likely critical for gonococcal growth, metabolism, and virulence, including genes encoding hypothetical proteins expressed during mucosal infection. In addition, network analysis revealed overlap in the response of N. gonorrhoeae to incubation with neutrophils and exposure to hydrogen peroxide stress in vitro. Network analysis also identified new targets of the gonococcal global regulatory protein Fur, while examination of the network neighborhood of genes allowed us to assign additional putative categories to several proteins. Collectively, the characterization of the first gene coexpression network for N. gonorrhoeae described here has revealed new regulatory pathways and new categories for proteins and has shown how processes important to gonococcal infection in both men and women are linked. This information fills a critical gap in our understanding of virulence strategies of this obligate human pathogen and will aid in the development of new treatment strategies for gonorrhea. IMPORTANCE Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection (STI) gonorrhea, a disease with high morbidity worldwide with an estimated 87 million cases annually. Current therapeutic and pharmacologic approaches to treat gonorrhea have been compromised by increased antibiotic resistance worldwide, including to the most recent FDA-approved antibiotic. New treatment strategies are urgently needed to combat this organism. In this study, we used network analysis to interrogate and define the coordination of pathways and processes in N. gonorrhoeae. An analysis of the gonococcal network was also used to assign categories to genes and to expand our understanding of regulatory strategies. Network analysis provides important insights into pathogenic mechanisms of this organism that will guide the design of new strategies for disease treatment.

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“…In addition to the prediction of ciprofloxacin susceptibility, our real-time PCR method could potentially be adapted to detect other mutations that may confer antimicrobial resistance. A recent study reported the presence of mosaic penA allele XXXIV in all N. gonorrhoeae isolates from major population centers in California with elevated MICs to ceftriaxone or cefixime (19), suggesting that this mosaic allele could serve as an appropriate target for prediction of increased extended-spectrum cephalosporin MICs in our local population. We found that the gyrA RT-PCR fit well into our current molecular diagnostic workflow; in particular, the use of remnant DNA extracted from the Cobas 4800 system allows a shorter turnaround time for producing gyrA genotype results-an approach demonstrated by others, in a recent report (20).…”

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confidence: 77%

Performance and Verification of a Real-Time PCR Assay Targeting the gyrA Gene for Prediction of Ciprofloxacin Resistance in Neisseria gonorrhoeae

et al. 2016

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cIn the United States, 19.2% of Neisseria gonorrhoeae isolates are resistant to ciprofloxacin. We evaluated a real-time PCR assay to predict ciprofloxacin susceptibility using residual DNA from the Roche Cobas 4800 CT/NG assay. The results of the assay were 100% concordant with agar dilution susceptibility test results for 100 clinical isolates. Among 76 clinical urine and swab specimens positive for N. gonorrhoeae by the Cobas assay, 71% could be genotyped. The test took 1.5 h to perform, allowing the physician to receive results in time to make informed clinical decisions. The sexually transmitted disease gonorrhea is the second most commonly reported notifiable disease in the United States, with 350,062 cases reported in 2014 (1). The etiologic agent of the disease, Neisseria gonorrhoeae, has become a major concern worldwide due to the high prevalence of resistance to antimicrobials that were at one time part of the standard treatment for the disease, including the sulfonamides, penicillins, narrow-spectrum cephalosporins, tetracyclines, macrolides, and fluoroquinolones (2). In the United States, multidrug-resistant N. gonorrhoeae is categorized as an urgent threat to public health by the Centers for Disease Control and Prevention (CDC) (3). As a result of emerging resistance, the CDC has issued several changes to the treatment guidelines for gonococcal infections, which included the removal of single-dose oral cephalosporins from the 2012 recommendations due to a significant decline in cefixime susceptibility among the gonococci (4). The current CDC treatment guideline now recommends the use of two drugs: a single intramuscular injection of ceftriaxone followed by a single dose of azithromycin administered orally (5).In the United States, the prevalence of fluoroquinolone-resistant gonococci has declined from its peak in 2007, when the CDC ceased recommending ciprofloxacin as empirical treatment for gonococcal infections (6). For example, the prevalence of ciprofloxacin-resistant N. gonorrhoeae isolates in San Francisco decreased dramatically from 44% in 2006 to 9.6% in 2009 (7), which coincided with these changes to national treatment guidelines. Currently, the proportion of U.S. isolates resistant to ciprofloxacin (MIC, Ն1.0 g/ml) is at 19.2% (CDC, unpublished data), suggesting that ciprofloxacin may still be a viable option in some cases for treatment of infections, the majority of which are caused by ciprofloxacin-susceptible isolates. However, as few laboratories routinely perform culture and susceptibility testing for N. gonorrhoeae, a molecular assay is needed to differentiate patients infected with a susceptible strain from those infected with a resistant strain. Resistance to ciprofloxacin is conferred by mutation in the Ser91 codon of the gyrA gene in Ͼ99% of all resistant isolates investigated to date, making this mutation an attractive target for prediction of ciprofloxacin susceptibility (8). In this study, we evaluated a real-time (RT)-PCR assay of the gyrA gene that was coupled with high-resol...

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Neisseria gonorrhoeaeStrain with Reduced Susceptibilities to Extended-Spectrum Cephalosporins

Cited by 16 publications

References 14 publications

The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women

The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women

Global Network Analysis of Neisseria gonorrhoeae Identifies Coordination between Pathways, Processes, and Regulators Expressed during Human Infection

Performance and Verification of a Real-Time PCR Assay Targeting the gyrA Gene for Prediction of Ciprofloxacin Resistance in Neisseria gonorrhoeae

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