Analysis of mutations within multiple genes associated with resistance in clinical isolate of Neisseria gonorrhoeae with reduced ceftriaxone susceptibility that shows a multidrug-resistance phenotype Masatoshi Tanaka, Hiroshi Nakayama, Kozaburo Huruya, Ichiro Konomi, Shinichiro Irie, Akiko Kanayama, Takeshi Saika, Intetsu Kobayashi

Introduction to antimicrobial resistance Since the development of Penicillin in 1920, some disease producing bacteria have been developing resistance to many antibiotics and other treatments This problem has greatly increased in profundity beginning in the late 1980’s Evolutionarily, there are at least three main ways that bacteria become less susceptible or resistant to drug treatment: mutation, conjugation, and transposition (Thompson, Bert. 1994)

(Prof. Robinson, 2004)

Paper Specific Recently found a strain of N. gonorrhoeae that is resistant to ceftriaxone treatment. This strain is also resistant to multiple other drug treatments. Research has shown that resistance of other drug treatments are likely due to mutations at penA, mtrR, and penB loci. This study was aimed at discovery of molecular basis for resistance of ceftriaxone

Methods 398 clinical isolates were collected for the study and screened for antimicrobial susceptibility. The testing included susceptibility analysis of penicillin G, tetracycline, ceftriaxone, cefixime, ciprofloxicin, azithromycin and spectinomycin. Guidelines set by the National Committee for Clinical Laboratory Standards (NCCLS) were followed After the testing five isolates were further identified as GP853, GP984, GP986, GP998 and A69W.

methods continued… Polymerase Chain Reaction (PCR) amplification and DNA sequencing were performed to the loci penA, ponA, mtrR, penB and gyrA and parC using various primers.

Results The strain GP853 was found to have reduced susceptibility to ceftriaxone, as well as penicillin, tetracycline, azithromycin and ciprofloxacin. At the penA gene, mutations were found that coded for resistance to penicillin. Mutations at the mtrR gene were found to be where reduced susceptibility to ceftriaxone was coded for. Looking at the penB gene, mutations coding for reduced permeability of penicillins and tetracyclines were found

results continued… At the gyrA and parC genes, mutations and amino acid substitutions were found that resist ciprofloxacin. In the domain of penA, the horizontal gene transfer of antimicrobial resistant material from other Neisseria species is suggested to be the form of evolution causing resistance to cephalosporins in the GP853 strain.

World Application Increased public knowledge on the proper use of antibiotics and treatments. Reduced use of antibacterials More research on a molecular level of the logistics about resistance and ways to beat it. (Antimicrobial resistance, 1997) Surveillance by hospitals, researchers and private doctors should be conducted on which drugs are resistant to antimicrobials. (Antimicrobial resistance, 1997)

Works Cited Tanaka M, Nakayama H, Huruya K, Konomi I, et al. Analysis of mutations within multiple genes associated with resistance in a clinical isolate of Neisseria gonorrhoeae with reduced ceftriaxone susceptibility that shows a multidrug-resistant phenotype. Antimicrobial Agents 2006, 20-26 Prof. Robinson. “History of antibiotic resistance.” Antibacterial resistance and Mycobacterium tuberculosis. Dec. 10, 2006. UCLA. Winter, 2004. http://ftaylor.bol.ucla.edu/history.html Gray-Owen, Scott D. “Host cellular response to the pathogenic Neisseria.” Dec. 10, 2006. The University of Toronto. http://www.utoronto.ca/medicalgenetics/Pls/Gray-Owen.htm “Antimicrobial resistance.” National Foundation for Infectious Diseases. Dec. 11, 2006. April 1997. http://www.nfid.org/factsheets/antimicrobial.html Thompson, Bert. “Bacterial Antibiotic resistance and Evolution.” Dec. 9, 2006. Reason and Revelation, 1994 14(8): 61-63