under the microscope
By Rodney E . Rohde , PhD , MS , SM ( ASCP ) CMSV CM , MBCM , FACSc
Gonorrhea : Not Your Usual STI Anymore
Antimicrobial resistance ( AMR ) happens when microbes such as viruses ( e . g ., HIV ), bacteria ( e . g ., Neisseria gonorrhea and fungi ( e . g ., Candida auris ) develop the ability to resist , and even defeat , the antimicrobial drugs designed to kill them . Unfortunately , AMR has been a threat to our collective and global health since the first antibiotic , penicillin , was found and utilized . To put it plainly , AMR means the germs are not killed and continue to grow . Many pathogenic microbes have become dangerously close to the pre-antimicrobial era with some only have one class or a single antimicrobial available to clinicians for treatment . Gonorrhea has developed resistance to nearly all the antibiotics used for its treatment . Currently , there is one last recommended and effective class of antibiotics , cephalosporins , to treat this common infection . This is an urgent public health threat because gonorrhea control in the United States largely relies on our ability to successfully treat the infection .
Microbes , like N . gonorrhea and others , are built to evolve in a diabolical way to outsmart the antibiotics and other antimicrobial drugs used to kill eliminate deadly infections . Due to this global problem , we must continuously monitor for resistance in not only humans , but also in animal and environmental settings to encourage the research and development of new drugs for gonorrhea treatment . Likewise , we must all work toward better stewardship of our antimicrobial drugs via accurate and appropriate medical laboratory testing that informs pharmaceutical accuracy and reduces empirical selection of a drug .
An Update : Neisseria gonorrhea
On Jan . 19 , 2023 , health officials in Massachusetts reported the detection of a novel strain of gonorrhea with resistance or reduced susceptibility to the antibiotics used for treatment of the sexually transmitted infection ( STI ). It ’ s the first detection of the strain in the United States .
The case first presented to primary care with urethritis . The individual reported no known exposure to gonococcal infection or initial disclosure of risk factors . The infection likely initiated in Massachusetts , with no recent travel history reported , however , recent travel by sex partners could not be ruled out . Successful treatment of the patient occurred with ceftriaxone 500 mg IM , the currently recommended treatment for gonorrhea , followed by documented subsequent negative testing at urethral , pharyngeal , and rectal sites . Reduced in vitro susceptibility by the isolate to cephalosporins ( ceftriaxone , cefixime , cefoxitin ) and azithromycin was demonstrated ; and resistance to ciprofloxacin , penicillin and tetracycline , via E-test and agar dilution methods .
The isolate is of a multilocus sequence type ( ST ), MLST 8123 , which was originally identified in the Asia-Pacific region . Sequencing of the isolate confirmed the presence of a mosaic penA60 allele which confers reduced ceftriaxone susceptibility . In the United Kingdom , eight cases with the identical MLST 8123 ST , also exhibited reduced ceftriaxone susceptibility , between December 2021 and June 2022 . All UK individuals were successfully treated with ceftriaxone . However , emergence of this strain indicates N . gonorrhoeae ’ s ongoing evolution for development of resistance to AMR treatment .
Gonorrhea is the second-most-reported STI in the United States . In Massachusetts , laboratory-confirmed cases more than quadrupled since a nadir of 1,976 in 2009 , to 8,133 in 2021 . With rising case numbers , Massachusetts Department of Public Health officials reported this particular strain was found in two residents of the state , both of whom were cured . An alert to clinicians in the state has been issued for a heightened lookout for the new strain with a warning that the two cases are an urgent sign that gonorrhea is becoming less responsive to treatment .
Diagnosis
The CDC and U . S . Preventive Services Task Force recommend routine gonorrhea screening for sexually active women younger than 24 years and women 25 years or older who are at increased risk . Screening is also recommended for sexually active men who have sex with men , at least annually but up to every three months if at increased risk . Screening recommendations should be adapted based on anatomy and reported sites of sexual exposure .
Culture and / or nucleic acid amplification testing ( NAAT ) are available for detecting urogenital ( urine , urethral , vaginal , cervical ) and extragenital ( rectal , oropharyngeal , conjunctival ) infection with N . gonorrhoeae . NAAT sensitivity and specificity for detecting N . gonorrhoeae from urogenital and extragenital anatomic sites are superior to culture but vary by NAAT type . However , NAAT is not approved for sequencing or antimicrobial susceptibility testing for clinical purposes . Because N . gonorrhoeae has demanding laboratory growth requirements , optimal culture recovery rates are achieved when swab specimens are inoculated directly and when growth medium is promptly incubated in a carbon dioxide ( CO2 ) -enriched environment . Non-nutritive swab transport systems ( e . g ., Amies agar gel ) that may maintain gonococcal viability for less than 24 hours in ambient temperatures , are available for sample transport to clinical microbiology laboratories .
Important Reminders
The CDC named gonorrhea as one of the three most urgent threats posed by antibiotic-resistant bacteria 10 years ago . Both U . S . and world health authorities created public health programs to reduce new cases of gonorrhea in hopes of controlling the bacteria until vaccines and new treatments arrive .
The Massachusetts cases bring strong reminders of the ongoing dangerous AMR threat globally . The cases are the first laboratory confirmed gonorrhea isolates to evolve and sidestep six of the seven drugs tracked by public health and healthcare for potential resistance . The isolates carry a gene mutation ( penA60 allele ) linked to previous ceftriaxone-resistant cases in Nevada , the United Kingdom , and Asia .
Rodney E . Rohde , PhD , MS , SM ( ASCP ) CM SVCM , MBCM , FACSc , serves as chair and professor of the Clinical Laboratory Science Program at Texas State University . Follow him on Twitter @ RodneyRohde / @ TXST _ CLS , or on his website : http :// rodneyerohde . wp . txstate . edu /