Neisseria gonorrhoeae and extended-spectrum cephalosporins in California: surveillance and molecular detection of mosaic penA

BMC Infectious Diseases

Research Article

Daniella Lowenberg¹  Severin Gose²  Duylinh Nguyen²  Mark Pandori²  Heidi Bauer³  Michael Samuel³ 

[1] California Polytechnic State University at San Luis Obispo, 1 Grand Ave, 93405, San Luis Obispo, CA, USA;Currently at PharmGKB, Standford University, CA, Stanford University 1501 California Avenue, 94304, Palo Alto, CA, USA;San Francisco Department of Public Health, 101 Grove St. Rm. 419, 94102, San Francisco, CA, USA;Sexually Transmitted Disease Control Branch, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health, 850 Marina Bay Pkwy, 94804, Richmond, CA, USA;

关键词: Neisseria gonorrhoeae;    Antimicrobial resistance;    Extended-spectrum cephalosporin;    penA;    Real-time polymerase chain reaction;   

DOI  :  10.1186/1471-2334-13-570

 received in 2013-09-12, accepted in 2013-11-28,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe spread of Neisseria gonorrhoeae strains with mosaic penA alleles and reduced susceptibility to extended-spectrum cephalosporins is a major public health problem. While much work has been performed internationally, little is known about the genetics or molecular epidemiology of N. gonorrhoeae isolates with reduced susceptibility to extended-spectrum cephalosporins in the United States. The majority of N. gonorrhoeae infections are diagnosed without a live culture. Molecular tools capable of detecting markers of extended-spectrum cephalosporin resistance are needed.MethodsUrethral N. gonorrhoeae isolates were collected from 684 men at public health clinics in California in 2011. Minimum inhibitory concentrations (MICs) to ceftriaxone, cefixime, cefpodoxime and azithromycin were determined by Etest and categorized according to the U.S. Centers for Disease Control 2010 alert value breakpoints. 684 isolates were screened for mosaic penA alleles using real-time PCR (RTPCR) and 59 reactive isolates were subjected to DNA sequencing of their penA alleles and Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST). To increase the specificity of the screening RTPCR in detecting isolates with alert value extended-spectrum cephalosporin MICs, the primers were modified to selectively amplify the mosaic XXXIV penA allele.ResultsThree mosaic penA alleles were detected including two previously described alleles (XXXIV, XXXVIII) and one novel allele (LA-A). Of the 29 isolates with an alert value extended-spectrum cephalosporin MIC, all possessed the mosaic XXXIV penA allele and 18 were sequence type 1407, an internationally successful strain associated with multi-drug resistance. The modified RTPCR detected the mosaic XXXIV penA allele in urethral isolates and urine specimens and displayed no amplification of the other penA alleles detected in this study.ConclusionN. gonorrhoeae isolates with mosaic penA alleles and reduced susceptibility to extended-spectrum cephalosporins are currently circulating in California. Isolates with the same NG-MAST ST, penA allele and extended-spectrum cephalosporin MICs have caused treatment failures elsewhere. The RTPCR assay presented here may be useful for the detection of N. gonorrheoae isolates and clinical specimens with reduced extended-spectrum cephalosporin MICs in settings where antimicrobial susceptibility testing is unavailable. In an era of increasing antimicrobial resistance and decreasing culture capacity, molecular assays capable of detecting extended-spectrum cephalosporin of resistance are essential to public health.

【 授权许可】

CC BY   
© Gose et al.; licensee BioMed Central Ltd. 2013