Accuracy and reproducibility of the Etest to detect drug-resistant Neisseria gonorrhoeae to contemporary treatment.

PURPOSE: Neisseria gonorrhoeae is a sexually transmitted bacterial pathogen that continues to evolve to become resistant to known antibiotics. In preparing for potential emergence, the Centers for Disease Control and Prevention recommends that clinical laboratories maintain or develop protocols to assess antibiotic susceptibly for this organism. This study examines the intra-laboratory variability of using the Etest method to provide consistent MIC values for N. gonorrhoeae and also compared the results of the Etest to known agar dilution MIC values. METHODOLOGY: Clinical N. gonorrhoeae isolates, 100 paired duplicates, were tested by eight laboratories for antibiotic susceptibility to ceftriaxone, cefixime and azithromycin using Etest strips.Results/Key findings. Overall, >80 % of the paired Etest MIC values were within one log2 dilution of the replicate. When compared to the agar dilution reference method, the cefixime Etest MIC values were consistently underreported by one dilution (seven laboratories) or two dilutions (one laboratory). The azithromycin Etest MIC values agreed 90.7 % with the agar dilution MIC values while the agreement with ceftriaxone was 90.9 %. CONCLUSION: Overall, the Etest method yielded reproducible MIC values within each laboratory with the azithromycin and ceftriaxone MIC results consistent to the reference agar dilution method while the cefixime result tended to provide a lower MIC value.

Cluster of Neisseria gonorrhoeae Isolates With High-level Azithromycin Resistance and Decreased Ceftriaxone Susceptibility, Hawaii, 2016.

BACKGROUND: The Centers for Disease Control and Prevention (CDC) currently recommends dual therapy with ceftriaxone and azithromycin for gonorrhea to ensure effective treatment and slow emergence of antimicrobial resistance. Since 2013, the prevalence of reduced azithromycin susceptibility increased in the United States; however, these strains were highly susceptible to cephalosporins. We identified a cluster of Neisseria gonorrhoeae isolates with high-level azithromycin resistance, several of which also demonstrated decreased ceftriaxone susceptibility. METHODS: Eight N. gonorrhoeae isolates collected from 7 patients on Oahu, Hawaii, seen 21 April 2016 through 10 May 2016 underwent routine Etest antimicrobial susceptibility testing by the Hawaii Department of Health. All demonstrated elevated azithromycin minimum inhibitory concentrations (MICs) >256 µg/mL and elevated ceftriaxone MICs (≥0.125 µg/mL). Isolates were sent to the University of Washington and CDC for confirmatory agar dilution testing; sequence data were sent to CDC for analysis. All patients were interviewed and treated, and when possible, partners were interviewed, tested, and treated. RESULTS: All isolates had azithromycin MICs >16 µg/mL and 5 had ceftriaxone MICs = 0.125 µg/mL by agar dilution. All isolates were ß-lactamase positive and were resistant to penicillin, tetracycline, and ciprofloxacin. Genomic analysis revealed genetic relatedness. No patients reported recent travel or antibiotic use, and no male patients reported male sex partners. All patients were successfully treated. CONCLUSIONS: This cluster of genetically related gonococcal isolates with decreased ceftriaxone susceptibility and high-level azithromycin resistance may bring the threat of treatment failure in the United States with the current recommended dual therapy one step closer.

Azithromycin Resistance and Decreased Ceftriaxone Susceptibility in Neisseria gonorrhoeae, Hawaii, USA.

During 2016, eight Neisseria gonorrhoeae isolates from 7 patients in Hawaii were resistant to azithromycin; 5 had decreased in vitro susceptibility to ceftriaxone. Genomic analysis demonstrated a distinct phylogenetic clade when compared with local contemporary strains. Continued evolution and widespread transmission of these strains might challenge the effectiveness of current therapeutic options.

Culture-negative prosthetic valve endocarditis with concomitant septicemia due to a nontoxigenic Corynebacterium diphtheriae biotype gravis isolate in a patient with multiple risk factors.

A 54-year-old female with a prosthetic mitral valve presented with a 3-day history of dizziness, subjective fever, and chills. Blood cultures were positive for a pleomorphic Gram-positive rod. Initial phenotypic testing could only support the identification of a Corynebacterium species. Nucleic acid sequencing (16S rRNA) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) were conclusive for Corynebacterium diphtheriae. Definitive phenotypic testing classified the strain as nontoxigenic C. diphtheriae biotype Gravis.

Gonococcal susceptibility to cephalosporins--Hawaii, 2003 to 2011.

Among gonococcal isolates examined at the Hawaii State Laboratory Division from 2003 to 2011, the prevalence of elevated cefixime minimum inhibitory concentrations (MICs; ≥0.064 µg/mL) and elevated cefpodoxime MICs (≥0.19 µg/mL) increased over time. In contrast, few isolates exhibited elevated ceftriaxone MICs (≥0.094 µg/mL), and the prevalence of elevated ceftriaxone MICs did not change.

Fluoroquinolone resistance among Neisseria gonorrhoeae isolates in Hawaii, 1990-2000: role of foreign importation and increasing endemic spread.

OBJECTIVES: In 1999, an increase in ciprofloxacin-resistant Neisseria gonorrhoeae isolates was identified in Hawaii, prompting initiation of investigative studies. GOALS: The goal of this study was epidemiologic evaluation of this increase. STUDY: The authors conducted a review of laboratory data; case-series and case-control studies based on medical record review; and a prospective case-control study based on patient interviews. RESULTS: A total of 10.4% (21 of 201) of gonococcal isolates from Hawaii in 2000 were ciprofloxacin-resistant compared with <1.5% per year from 1990 to 1997. From medical record review for patients diagnosed with ciprofloxacin-resistant N. gonorrhoeae infection from 1990 to 1999, 59% were Asian/Pacific Islanders and 91% were heterosexual. From review of 1998 and 1999 sexually transmitted disease (STD) clinic medical records, patients with ciprofloxacin-resistant N. gonorrhoeae were more likely to report recent foreign travel or a sex partner with recent foreign travel than patients with ciprofloxacin-susceptible N. gonorrhoeae (6 of 12 vs. 10 of 117, P <0.001), but 50% (6 of 12) acquired a ciprofloxacin-resistant strain locally from a partner with no recent travel. In 2000, 70% (7 of 10) of STD clinic patients with ciprofloxacin-resistant N. gonorrhoeae acquired their infection locally from partners with no reported recent travel. CONCLUSIONS: Infections with ciprofloxacin-resistant N. gonorrhoeae are increasing and evolving in Hawaii.

The epidemiology of fluoroquinolone-resistant Neisseria gonorrhoeae in Hawaii, 2001.

Increases in the number of infections with fluoroquinolone-resistant Neisseria gonorrhoeae in Asia and the United States threaten the efficacy of fluoroquinolones as inexpensive, single-dose, orally administered treatments for gonorrhea. This report describes the findings of a field investigation of an increase in the number of infections with ciprofloxacin-resistant N. gonorrhoeae (CipRGC) in Hawaii in 2001. We conducted a case review of 53 patients with CipRGC, who constituted 20% of the 267 patients with cultures positive for N. gonorrhoeae during this period. Nearly one-half of patients with CipRGC were seen by clinicians in private practice, one-third were seen by clinicians at a sexually transmitted diseases (STD) clinic, and only 2% were seen by clinicians in the military. Among the 117 patients with culture-confirmed gonorrhea who attended the public STD clinic, we found a prevalence of infection with CipRGC of 17%. The demographic and clinical characteristics of patients with CipRGC were similar to those of patients with gonorrhea that was not resistant to ciprofloxacin, suggesting that fluoroquinolone-resistant gonorrhea has become endemic in Hawaii.

Multidrug-resistant Neisseria gonorrhoeae with decreased susceptibility to cefixime-Hawaii, 2001.

We report 4 urogenital Neisseria gonorrhoeae isolates recovered from 3 patients that demonstrated resistance to penicillin, tetracycline, and ciprofloxacin and reduced susceptibility to cefixime. This report of the first 3 patients in the United States identified with this multidrug-resistant strain may portend an emerging problem for clinicians and public health officials.