Browsing by Author "Stephens, David S."

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    Antibiotic Susceptibility Profile for the US Neisseria meningitidis Urethritis Clade
    (Oxford University Press, 2022-12-12) Bazan, Jose A.; Tzeng, Yih-Ling; Bischof, Katarina M.; Satola, Sarah W.; Stephens, David S.; Edwards, Jennifer L.; Carter, Alexandria; Snyder, Brandon; Norris Turner, Abigail; Microbiology and Immunology, School of Medicine
    The US Neisseria meningitidis urethritis clade (US_NmUC) harbors gonococcal deoxyribonucleic acid alleles and causes gonorrhea-like urogenital tract disease. A large convenience sample of US_NmUC isolates (N = 122) collected between January 2015 and December 2019 in Columbus, Ohio demonstrated uniform susceptibility to antibiotics recommended for gonorrhea treatment and meningococcal chemoprophylaxis.
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    Emergence of a new Neisseria meningitidis clonal complex 11 lineage 11.2 clade as an effective urogenital pathogen
    (Proceedings of the National Academy of Sciences, 2017-04-18) Tzeng, Yih-Ling; Bazan, Jose A.; Turner, Abigail Norris; Wang, Xin; Retchless, Adam C.; Read, Timothy D.; Toh, Evelyn; Nelson, David E.; Del Rio, Carlos; Stephens, David S.; Department of Microbiology and Immunology, School of Medicine
    Neisseria meningitidis (Nm) clonal complex 11 (cc11) lineage is a hypervirulent pathogen responsible for outbreaks of invasive meningococcal disease, including among men who have sex with men, and is increasingly associated with urogenital infections. Recently, clusters of Nm urethritis have emerged primarily among heterosexual males in the United States. We determined that nonencapsulated meningococcal isolates from an ongoing Nm urethritis outbreak among epidemiologically unrelated men in Columbus, Ohio, are linked to increased Nm urethritis cases in multiple US cities, including Atlanta and Indianapolis, and that they form a unique clade (the US Nm urethritis clade, US_NmUC). The isolates belonged to the cc11 lineage 11.2/ET-15 with fine type of PorA P1.5-1, 10-8; FetA F3-6; PorB 2-2 and express a unique FHbp allele. A common molecular fingerprint of US_NmUC isolates was an IS1301 element in the intergenic region separating the capsule ctr-css operons and adjacent deletion of cssA/B/C and a part of csc, encoding the serogroup C capsule polymerase. This resulted in the loss of encapsulation and intrinsic lipooligosaccharide sialylation that may promote adherence to mucosal surfaces. Furthermore, we detected an IS1301-mediated inversion of an ∼20-kb sequence near the cps locus. Surprisingly, these isolates had acquired by gene conversion the complete gonococcal denitrification norB-aniA gene cassette, and strains grow well anaerobically. The cc11 US_NmUC isolates causing urethritis clusters in the United States may have adapted to a urogenital environment by loss of capsule and gene conversion of the Neisseria gonorrheae norB-aniA cassette promoting anaerobic growth.
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    Heteroresistance to the model antimicrobial peptide polymyxin B in the emerging Neisseria meningitidis lineage 11.2 urethritis clade: mutations in the pilMNOPQ operon
    (Wiley, 2018) Tzeng, Yih-Ling; Berman, Zachary; Toh, Evelyn; Bazan, Jose A.; Turner, Abigail Norris; Retchless, Adam C.; Wang, Xin; Nelson, David E.; Stephens, David S.; Microbiology and Immunology, School of Medicine
    Clusters of Neisseria meningitidis (Nm) urethritis among primarily heterosexual males in multiple US cities have been attributed to a unique non‐encapsulated meningococcal clade (the US Nm urethritis clade, US_NmUC) within the hypervirulent clonal complex 11. Resistance to antimicrobial peptides (AMPs) is a key feature of urogenital pathogenesis of the closely related species, Neisseria gonorrhoeae. The US_NmUC isolates were found to be highly resistant to the model AMP, polymyxin B (PmB, MICs 64–256 µg ml–1). The isolates also demonstrated stable subpopulations of heteroresistant colonies that showed near total resistant to PmB (MICs 384–1024 µg ml–1) and colistin (MIC 256 µg ml–1) as well as enhanced LL‐37 resistance. This is the first observation of heteroresistance in N. meningitidis. Consistent with previous findings, overall PmB resistance in US_NmUC isolates was due to active Mtr efflux and LptA‐mediated lipid A modification. However, whole genome sequencing, variant analyses and directed mutagenesis revealed that the heteroresistance phenotypes and very high‐level AMP resistance were the result of point mutations and IS1655 element movement in the pilMNOPQ operon, encoding the type IV pilin biogenesis apparatus. Cross‐resistance to other classes of antibiotics was also observed in the heteroresistant colonies. High‐level resistance to AMPs may contribute to the pathogenesis of US_NmUC.
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    Heteroresistance to the model antimicrobial peptide polymyxin B in the emerging Neisseria meningitidis lineage 11.2 urethritis clade: mutations in the pilMNOPQ operon
    (Wiley, 2019-01) Tzeng, Yih-Ling; Berman, Zachary; Toh, Evelyn; Bazan, Jose A.; Turner, Abigail Norris; Retchless, Adam C.; Wang, Xin; Nelson, David E.; Stephens, David S.; Microbiology and Immunology, School of Medicine
    Clusters of Neisseria meningitidis (Nm) urethritis among primarily heterosexual males in multiple US cities have been attributed to a unique non‐encapsulated meningococcal clade (the US Nm urethritis clade, US_NmUC) within the hypervirulent clonal complex 11. Resistance to antimicrobial peptides (AMPs) is a key feature of urogenital pathogenesis of the closely related species, Neisseria gonorrhoeae. The US_NmUC isolates were found to be highly resistant to the model AMP, polymyxin B (PmB, MICs 64–256 µg ml–1). The isolates also demonstrated stable subpopulations of heteroresistant colonies that showed near total resistant to PmB (MICs 384–1024 µg ml–1) and colistin (MIC 256 µg ml–1) as well as enhanced LL‐37 resistance. This is the first observation of heteroresistance in N. meningitidis. Consistent with previous findings, overall PmB resistance in US_NmUC isolates was due to active Mtr efflux and LptA‐mediated lipid A modification. However, whole genome sequencing, variant analyses and directed mutagenesis revealed that the heteroresistance phenotypes and very high‐level AMP resistance were the result of point mutations and IS1655 element movement in the pilMNOPQ operon, encoding the type IV pilin biogenesis apparatus. Cross‐resistance to other classes of antibiotics was also observed in the heteroresistant colonies. High‐level resistance to AMPs may contribute to the pathogenesis of US_NmUC.