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Genomic Epidemiology and Molecular Resistance Mechanisms of Azithromycin-Resistant Neisseria gonorrhoeae in Canada from 1997 to 2014. J Clin Microbiol 2016; 54:1304-13. [PMID: 26935729 DOI: 10.1128/jcm.03195-15] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/19/2016] [Indexed: 01/06/2023] Open
Abstract
The emergence of Neisseria gonorrhoeae strains with decreased susceptibility to cephalosporins and azithromycin (AZM) resistance (AZM(r)) represents a public health threat of untreatable gonorrhea infections. Genomic epidemiology through whole-genome sequencing was used to describe the emergence, dissemination, and spread of AZM(r) strains. The genomes of 213 AZM(r) and 23 AZM-susceptible N. gonorrhoeae isolates collected in Canada from 1989 to 2014 were sequenced. Core single nucleotide polymorphism (SNP) phylogenomic analysis resolved 246 isolates into 13 lineages. High-level AZM(r) (MICs ≥ 256 μg/ml) was found in 5 phylogenetically diverse isolates, all of which possessed the A2059G mutation (Escherichia coli numbering) in all four 23S rRNA alleles. One isolate with high-level AZM(r) collected in 2009 concurrently had decreased susceptibility to ceftriaxone (MIC = 0.125 μg/ml). An increase in the number of 23S rRNA alleles with the C2611T mutations (E. coli numbering) conferred low to moderate levels of AZM(r) (MICs = 2 to 4 and 8 to 32 μg/ml, respectively). Low-level AZM(r) was also associated with mtrR promoter mutations, including the -35A deletion and the presence of Neisseria meningitidis-like sequences. Geographic and temporal phylogenetic clustering indicates that emergent AZM(r) strains arise independently and can then rapidly expand clonally in a region through local sexual networks.
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52
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Failure of azithromycin 2.0 g in the treatment of gonococcal urethritis caused by high-level resistance in California. Sex Transm Dis 2015; 42:279-80. [PMID: 25868141 DOI: 10.1097/olq.0000000000000265] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report a treatment failure to azithromycin 2.0 g caused by a urethral Neisseria gonorrhoeae isolate with high-level azithromycin resistance in California. This report describes the epidemiological case investigation and phenotypic and genetic characterization of the treatment failure isolate.
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53
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Trembizki E, Buckley C, Donovan B, Chen M, Guy R, Kaldor J, Lahra MM, Regan DG, Smith H, Ward J, Whiley DM. Direct real-time PCR-based detection of Neisseria gonorrhoeae 23S rRNA mutations associated with azithromycin resistance. J Antimicrob Chemother 2015; 70:3244-9. [PMID: 26338048 DOI: 10.1093/jac/dkv274] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/10/2015] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Surveillance for Neisseria gonorrhoeae azithromycin resistance is of growing importance given increasing use of ceftriaxone and azithromycin dual therapy for gonorrhoea treatment. In this study, we developed two real-time PCR methods for direct detection of two key N. gonorrhoeae 23S rRNA mutations associated with azithromycin resistance. METHODS The real-time PCR assays, 2611-PCR and 2059-PCR, targeted the gonococcal 23S rRNA C2611T and A2059G mutations, respectively. A major design challenge was that gonococcal 23S rRNA sequences have high sequence homology with those of commensal Neisseria species. To limit the potential for cross-reaction, 'non-template' bases were utilized in primer sequences. The performance of the methods was initially assessed using a panel of gonococcal (n = 70) and non-gonococcal (n = 28) Neisseria species. Analytical specificity was further assessed by testing N. gonorrhoeae nucleic acid amplification test (NAAT)-negative clinical samples (n = 90), before being applied to N. gonorrhoeae NAAT-positive clinical samples (n = 306). RESULTS Cross-reactions with commensal Neisseria strains remained evident for both assays; however, cycle threshold (Ct) values were significantly delayed, indicating reduced sensitivity for non-gonococcal species. For the N. gonorrhoeae NAAT-negative clinical samples, 7/21 pharyngeal samples provided evidence of cross-reaction (Ct values >40 cycles); however, the remaining urogenital and rectal swab samples were negative. In total, the gonococcal 2611 and 2059 23S rRNA nucleotides were both successfully characterized in 266/306 (87%) of the N. gonorrhoeae NAAT-positive clinical specimens. CONCLUSIONS Real-time PCR detection of gonococcal 23S rRNA mutations directly from clinical samples is feasible and may enhance culture- and non-culture-based N. gonorrhoeae resistance surveillance.
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Affiliation(s)
- Ella Trembizki
- Queensland Paediatric Infectious Diseases (QPID) Laboratory, Queensland Children's Medical Research Institute, Brisbane, Queensland 4029, Australia UQ Child Health Research Centre, School of Medicine, The University of Queensland, Brisbane, Queensland 4029, Australia
| | - Cameron Buckley
- Queensland Paediatric Infectious Diseases (QPID) Laboratory, Queensland Children's Medical Research Institute, Brisbane, Queensland 4029, Australia UQ Child Health Research Centre, School of Medicine, The University of Queensland, Brisbane, Queensland 4029, Australia
| | - Basil Donovan
- Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia Sydney Sexual Health Centre, Sydney Hospital, Sydney, New South Wales 2000, Australia
| | - Marcus Chen
- Melbourne Sexual Health Centre, Alfred Health, Carlton, Victoria 3053, Australia Central Clinical School, Monash University, Melbourne, Victoria 3800, Australia
| | - Rebecca Guy
- Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - John Kaldor
- Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Monica M Lahra
- WHO Collaborating Centre for STD, Microbiology Department, South Eastern Area Laboratory Services, Prince of Wales Hospital, Sydney, New South Wales 2031, Australia
| | - David G Regan
- Kirby Institute, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Helen Smith
- Public Health Microbiology, Public and Environmental Health, Queensland Health Forensic and Scientific Services, Archerfield, Queensland 4107, Australia
| | - James Ward
- South Australian Health and Medical Research Institute, Adelaide, South Australia 5000, Australia
| | - David M Whiley
- Queensland Paediatric Infectious Diseases (QPID) Laboratory, Queensland Children's Medical Research Institute, Brisbane, Queensland 4029, Australia UQ Child Health Research Centre, School of Medicine, The University of Queensland, Brisbane, Queensland 4029, Australia
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Xue J, Ni C, Zhou H, Zhang C, van der Veen S. Occurrence of high-level azithromycin-resistant Neisseria gonorrhoeae isolates in China. J Antimicrob Chemother 2015; 70:3404-5. [PMID: 26316384 DOI: 10.1093/jac/dkv266] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Juan Xue
- Department of Microbiology and Parasitology, Research Center of Infection and Immunity, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Chunshan Ni
- Department of Microbiology and Parasitology, Research Center of Infection and Immunity, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Haiyong Zhou
- Urology Department, Zhejiang Xiaoshan Hospital, Hangzhou, China
| | - Chuanling Zhang
- Clinical Laboratory, Zhejiang Xiaoshan Hospital, Hangzhou, China
| | - Stijn van der Veen
- Department of Microbiology and Parasitology, Research Center of Infection and Immunity, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
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55
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Antimicrobial resistance in Neisseria gonorrhoeae in the 21st century: past, evolution, and future. Clin Microbiol Rev 2015; 27:587-613. [PMID: 24982323 DOI: 10.1128/cmr.00010-14] [Citation(s) in RCA: 764] [Impact Index Per Article: 84.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Neisseria gonorrhoeae is evolving into a superbug with resistance to previously and currently recommended antimicrobials for treatment of gonorrhea, which is a major public health concern globally. Given the global nature of gonorrhea, the high rate of usage of antimicrobials, suboptimal control and monitoring of antimicrobial resistance (AMR) and treatment failures, slow update of treatment guidelines in most geographical settings, and the extraordinary capacity of the gonococci to develop and retain AMR, it is likely that the global problem of gonococcal AMR will worsen in the foreseeable future and that the severe complications of gonorrhea will emerge as a silent epidemic. By understanding the evolution, emergence, and spread of AMR in N. gonorrhoeae, including its molecular and phenotypic mechanisms, resistance to antimicrobials used clinically can be anticipated, future methods for genetic testing for AMR might permit region-specific and tailor-made antimicrobial therapy, and the design of novel antimicrobials to circumvent the resistance problems can be undertaken more rationally. This review focuses on the history and evolution of gonorrhea treatment regimens and emerging resistance to them, on genetic and phenotypic determinants of gonococcal resistance to previously and currently recommended antimicrobials, including biological costs or benefits; and on crucial actions and future advances necessary to detect and treat resistant gonococcal strains and, ultimately, retain gonorrhea as a treatable infection.
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56
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Analysis of Neisseria gonorrhoeae azithromycin susceptibility in the United States by the Gonococcal Isolate Surveillance Project, 2005 to 2013. Antimicrob Agents Chemother 2014; 59:998-1003. [PMID: 25451056 DOI: 10.1128/aac.04337-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Azithromycin, administered with ceftriaxone, is recommended by the CDC for the treatment of gonorrhea. Many experts have expressed concern about the ease with which Neisseria gonorrhoeae can acquire macrolide resistance. We sought to describe gonococcal azithromycin susceptibility in the United States and to determine whether azithromycin susceptibility has changed over time. We analyzed data from 2005 to 2013 from the Gonococcal Isolate Surveillance Project, a CDC-supported sentinel surveillance network that monitors gonococcal antimicrobial susceptibility. A total of 44,144 N. gonorrhoeae isolates were tested for azithromycin susceptibility by agar dilution methods. The overall azithromycin MIC50 was 0.25 μg/ml, and the MIC90 was 0.5 μg/ml. There were no overall temporal trends in geometric means. Isolates from men who had sex with men had significantly higher geometric mean MICs than isolates from men who had sex exclusively with women. The overall prevalence of reduced azithromycin susceptibility (MIC, ≥2 μg/ml) was 0.4% and varied by year from 0.3% (2006 and 2009) to 0.6% (2013). We did not find a clear temporal trend in gonococcal azithromycin MICs in the United States, and the prevalence of reduced azithromycin susceptibility remains low. These findings support the continued use of azithromycin in a combination therapy regimen for gonorrhea.
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57
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Whole-genome phylogenomic heterogeneity of Neisseria gonorrhoeae isolates with decreased cephalosporin susceptibility collected in Canada between 1989 and 2013. J Clin Microbiol 2014; 53:191-200. [PMID: 25378573 DOI: 10.1128/jcm.02589-14] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A large-scale, whole-genome comparison of Canadian Neisseria gonorrhoeae isolates with high-level cephalosporin MICs was used to demonstrate a genomic epidemiology approach to investigate strain relatedness and dynamics. Although current typing methods have been very successful in tracing short-chain transmission of gonorrheal disease, investigating the temporal evolutionary relationships and geographical dissemination of highly clonal lineages requires enhanced resolution only available through whole-genome sequencing (WGS). Phylogenomic cluster analysis grouped 169 Canadian strains into 12 distinct clades. While some N. gonorrhoeae multiantigen sequence types (NG-MAST) agreed with specific phylogenomic clades or subclades, other sequence types (ST) and closely related groups of ST were widely distributed among clades. Decreased susceptibility to extended-spectrum cephalosporins (ESC-DS) emerged among a group of diverse strains in Canada during the 1990s with a variety of nonmosaic penA alleles, followed in 2000/2001 with the penA mosaic X allele and then in 2007 with ST1407 strains with the penA mosaic XXXIV allele. Five genetically distinct ESC-DS lineages were associated with penA mosaic X, XXXV, and XXXIV alleles and nonmosaic XII and XIII alleles. ESC-DS with coresistance to azithromycin was observed in 5 strains with 23S rRNA C2599T or A2143G mutations. As the costs associated with WGS decline and analysis tools are streamlined, WGS can provide a more thorough understanding of strain dynamics, facilitate epidemiological studies to better resolve social networks, and improve surveillance to optimize treatment for gonorrheal infections.
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58
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Rice PA. Editorial commentary: The shifting sands of gonococcal antimicrobial resistance. Clin Infect Dis 2014; 59:1092-4. [PMID: 25031290 DOI: 10.1093/cid/ciu526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Peter A Rice
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester
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59
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Trembizki E, Doyle C, Jennison A, Smith H, Bates J, Lahra M, Whiley D. A Neisseria gonorrhoeae strain with a meningococcal mtrR sequence. J Med Microbiol 2014; 63:1113-1115. [DOI: 10.1099/jmm.0.074286-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Ella Trembizki
- Queensland Children’s Medical Research Institute, The University of Queensland, Queensland, Australia
- Queensland Paediatric Infectious Diseases Laboratory, Queensland Children’s Health Services, Queensland, Australia
| | - Christine Doyle
- Public Health Microbiology, Queensland Health Forensic and Scientific Services, Archerfield, Queensland, Australia
| | - Amy Jennison
- Public Health Microbiology, Queensland Health Forensic and Scientific Services, Archerfield, Queensland, Australia
| | - Helen Smith
- Public Health Microbiology, Queensland Health Forensic and Scientific Services, Archerfield, Queensland, Australia
| | - John Bates
- Public Health Microbiology, Queensland Health Forensic and Scientific Services, Archerfield, Queensland, Australia
| | - Monica Lahra
- WHO Collaborating Centre for STD, Microbiology Department, South Eastern Area Laboratory Services, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - David Whiley
- Queensland Children’s Medical Research Institute, The University of Queensland, Queensland, Australia
- Queensland Paediatric Infectious Diseases Laboratory, Queensland Children’s Health Services, Queensland, Australia
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60
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Importance of multidrug efflux pumps in the antimicrobial resistance property of clinical multidrug-resistant isolates of Neisseria gonorrhoeae. Antimicrob Agents Chemother 2014; 58:3556-9. [PMID: 24733458 DOI: 10.1128/aac.00038-14] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The contribution of drug efflux pumps in clinical isolates of Neisseria gonorrhoeae that express extensively drug-resistant or multidrug-resistant phenotypes has heretofore not been examined. Accordingly, we assessed the effect on antimicrobial resistance of loss of the three gonococcal efflux pumps associated with a known capacity to export antimicrobials (MtrC-MtrD-MtrE, MacA-MacB, and NorM) in such clinical isolates. We report that the MIC of several antimicrobials, including seven previously and currently recommended for treatment was significantly impacted.
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61
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Chico RM, Hack BB, Newport MJ, Ngulube E, Chandramohan D. On the pathway to better birth outcomes? A systematic review of azithromycin and curable sexually transmitted infections. Expert Rev Anti Infect Ther 2013; 11:1303-32. [PMID: 24191955 PMCID: PMC3906303 DOI: 10.1586/14787210.2013.851601] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The WHO recommends the administration of sulfadoxine-pyrimethamine (SP) to all pregnant women living in areas of moderate (stable) to high malaria transmission during scheduled antenatal visits, beginning in the second trimester and continuing to delivery. Malaria parasites have lost sensitivity to SP in many endemic areas, prompting the investigation of alternatives that include azithromycin-based combination (ABC) therapies. Use of ABC therapies may also confer protection against curable sexually transmitted infections and reproductive tract infections (STIs/RTIs). The magnitude of protection at the population level would depend on the efficacy of the azithromycin-based regimen used and the underlying prevalence of curable STIs/RTIs among pregnant women who receive preventive treatment. This systematic review summarizes the efficacy data of azithromycin against curable STIs/RTIs.
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Affiliation(s)
- R Matthew Chico
- London School of Hygiene and Tropical Medicine Keppel Street, London, WC1E 7HT,UK
| | - Berkin B Hack
- Brighton and Sussex Medical School,Brighton, East Sussex, BN1 9PX,UK
| | - Melanie J Newport
- Brighton and Sussex Medical School,Brighton, East Sussex, BN1 9PX,UK
| | - Enesia Ngulube
- London School of Hygiene and Tropical Medicine Keppel Street, London, WC1E 7HT,UK
| | - Daniel Chandramohan
- London School of Hygiene and Tropical Medicine Keppel Street, London, WC1E 7HT,UK
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62
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First three Neisseria gonorrhoeae isolates with high-level resistance to azithromycin in Sweden: a threat to currently available dual-antimicrobial regimens for treatment of gonorrhea? Antimicrob Agents Chemother 2013; 58:624-5. [PMID: 24189248 DOI: 10.1128/aac.02093-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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63
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Unemo M, Nicholas RA. Emergence of multidrug-resistant, extensively drug-resistant and untreatable gonorrhea. Future Microbiol 2012; 7:1401-22. [PMID: 23231489 PMCID: PMC3629839 DOI: 10.2217/fmb.12.117] [Citation(s) in RCA: 313] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The new superbug Neisseria gonorrhoeae has retained resistance to antimicrobials previously recommended for first-line treatment and has now demonstrated its capacity to develop resistance to the extended-spectrum cephalosporin, ceftriaxone, the last remaining option for first-line empiric treatment of gonorrhea. An era of untreatable gonorrhea may be approaching, which represents an exceedingly serious public health problem. Herein, we review the evolution, origin and spread of antimicrobial resistance and resistance determinants (with a focus on extended-spectrum cephalosporins) in N. gonorrhoeae, detail the current situation regarding verified treatment failures with extended-spectrum cephalosporins and future treatment options, and highlight essential actions to meet the large public health challenge that arises with the possible emergence of untreatable gonorrhea. Essential actions include: implementing action/response plans globally and nationally; enhancing surveillance of gonococcal antimicrobial resistance, treatment failures and antimicrobial use/misuse; and improving prevention, early diagnosis and treatment of gonorrhea. Novel treatment strategies, antimicrobials (or other compounds) and, ideally, a vaccine must be developed.
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Affiliation(s)
- Magnus Unemo
- WHO Collaborating Centre for Gonorrhoea & Other STIs, National Reference Laboratory for Pathogenic Neisseria, Örebro University Hospital, SE-701 85 Örebro, Sweden.
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64
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Multiplex bead suspension array for screening Neisseria gonorrhoeae antibiotic resistance genetic determinants in noncultured clinical samples. J Mol Diagn 2012; 15:116-29. [PMID: 23159594 DOI: 10.1016/j.jmoldx.2012.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 08/15/2012] [Accepted: 08/24/2012] [Indexed: 11/22/2022] Open
Abstract
The increasing threat of antibiotic-resistant Neisseria gonorrhoeae highlights the need for new diagnostic options. A high-throughput multiplex bead suspension array assay was developed for profiling 29 N. gonorrhoeae genomic mutations and 2 plasmid genes conferring resistance to 6 antimicrobial agents: penicillin, ciprofloxacin, cefixime, tetracycline, azithromycin, and spectinomycin. The three steps of this assay include amplification of 12 N. gonorrhoeae chromosomal and plasmid loci, multiplex allele-specific primer extension reaction, and multiplex bead suspension array detection. Antibiotic resistance genetic determinants were identified successfully in 239 cervicovaginal N. gonorrhoeae-positive noncultured swab samples. This molecular assay can be used for detection of gonococci in clinical specimens, molecular typing, mutation profiling, and predictive assessment of N. gonorrhoeae susceptibility to antibiotics without the need for culture.
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65
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KOZHUSHNAYA OS, VASILIYEVA YEL, FRIGO NV, SOLOMKA VS. Mechanisms of the formation of Neisseria gonorrhoeae resistance to cephalosporins. VESTNIK DERMATOLOGII I VENEROLOGII 2012. [DOI: 10.25208/vdv729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The authors provide a review of the present-day literature data on the issues of studying the mechanisms of the formation of Neisseria gonorrhoeae resistance to third-generation cephalosporins. Studies in this field are needed in connection with the occurrence of strains resistant to third-generation cephalosporins as well as low-sensitivity strains. The authors emphasize the importance of mutations in porB, penA, mtrR, penB and ponA genes in the development of Neisseria gonorrhoeae resistance to β-lactam antibiotics and describe the prospects of studying the mosaic structure of the penA gene encoding the РВР2 protein as well as spatial structure of this protein.
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66
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Unemo M, Golparian D, Limnios A, Whiley D, Ohnishi M, Lahra MM, Tapsall JW. In vitro activity of ertapenem versus ceftriaxone against Neisseria gonorrhoeae isolates with highly diverse ceftriaxone MIC values and effects of ceftriaxone resistance determinants: ertapenem for treatment of gonorrhea? Antimicrob Agents Chemother 2012; 56:3603-9. [PMID: 22547617 PMCID: PMC3393402 DOI: 10.1128/aac.00326-12] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/23/2012] [Indexed: 12/24/2022] Open
Abstract
Clinical resistance to the currently recommended extended-spectrum cephalosporins (ESCs), the last remaining treatment options for gonorrhea, is being reported. Gonorrhea may become untreatable, and new treatment options are crucial. We investigated the in vitro activity of ertapenem, relative to ceftriaxone, against N. gonorrhoeae isolates and the effects of ESC resistance determinants on ertapenem. MICs were determined using agar dilution technique or Etest for international reference strains (n = 17) and clinical N. gonorrhoeae isolates (n = 257), which included the two extensively drug-resistant (XDR) strains H041 and F89 and additional isolates with high ESC MICs, clinical ESC resistance, and other types of clinical high-level and multidrug resistance (MDR). Genetic resistance determinants for ESCs (penA, mtrR, and penB) were sequenced. In general, the MICs of ertapenem (MIC(50) = 0.032 μg/ml; MIC(90) = 0.064 μg/ml) paralleled those of ceftriaxone (MIC(50) = 0.032 μg/ml; MIC(90) = 0.125 μg/ml). The ESC resistance determinants mainly increased the ertapenem MIC and ceftriaxone MIC at similar levels. However, the MIC ranges for ertapenem (0.002 to 0.125 μg/ml) and ceftriaxone (<0.002 to 4 μg/ml) differed, and the four (1.5%) ceftriaxone-resistant isolates (MIC = 0.5 to 4 μg/ml) had ertapenem MICs of 0.016 to 0.064 μg/ml. Accordingly, ertapenem had in vitro advantages over ceftriaxone for isolates with ceftriaxone resistance. These in vitro results suggest that ertapenem might be an effective treatment option for gonorrhea, particularly for the currently identified ESC-resistant cases and possibly in a dual antimicrobial therapy regimen. However, further knowledge regarding the genetic determinants (and their evolution) conferring resistance to both antimicrobials, and clear correlates between genetic and phenotypic laboratory parameters and clinical treatment outcomes, is essential.
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Affiliation(s)
- Magnus Unemo
- WHO Collaborating Centre for Gonorrhoea and Other STIs, National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Clinical Microbiology, Örebro University Hospital, Örebro, Sweden
| | - Daniel Golparian
- WHO Collaborating Centre for Gonorrhoea and Other STIs, National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Clinical Microbiology, Örebro University Hospital, Örebro, Sweden
| | - Athena Limnios
- WHO Collaborating Centre for STD, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - David Whiley
- Queensland Paediatric Infectious Diseases Laboratory, Queensland Children's Medical Research Institute, Children's Health Service District, Brisbane, Queensland, Australia
| | | | - Monica M. Lahra
- WHO Collaborating Centre for STD, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - John W. Tapsall
- WHO Collaborating Centre for STD, Prince of Wales Hospital, Sydney, New South Wales, Australia
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67
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Unemo M, Shafer WM. Antibiotic resistance in Neisseria gonorrhoeae: origin, evolution, and lessons learned for the future. Ann N Y Acad Sci 2012; 1230:E19-28. [PMID: 22239555 DOI: 10.1111/j.1749-6632.2011.06215.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The strict human pathogen Neisseria gonorrhoeae has caused gonorrhea for thousands of years, and currently gonorrhea is the second most prevalent bacterial sexually transmitted infection worldwide. Given the ancient nature of N. gonorrhoeae and its unique obligate relationship with humankind over the millennia, its remarkable ability to adapt to the host immune system and cause repeated infections, and its propensity to develop resistance to all clinically useful antibiotics, the gonococcus is an ideal pathogen on which to study the evolution of bacterial pathogenesis, including antimicrobial resistance, over the long term and within the host during infection. Recently, the first gonococcus displaying high-level resistance to ceftriaxone, identified in Japan, was characterized in detail. Ceftriaxone is the last remaining option for empirical first-line treatment, and N. gonorrhoeae now seems to be evolving into a true "superbug." In the near future, gonorrhea may become untreatable in certain circumstances. Herein, the history of antibiotics used for treatment of gonorrhea, the evolution of resistance emergence in N. gonorrhoeae, the linkage between resistance and biological fitness of N. gonorrhoeae, lessons learned, and future perspectives are reviewed and discussed.
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Affiliation(s)
- Magnus Unemo
- National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Microbiology, Örebro University Hospital, Örebro, Sweden.
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68
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High-level cefixime- and ceftriaxone-resistant Neisseria gonorrhoeae in France: novel penA mosaic allele in a successful international clone causes treatment failure. Antimicrob Agents Chemother 2011; 56:1273-80. [PMID: 22155830 DOI: 10.1128/aac.05760-11] [Citation(s) in RCA: 473] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Recently, the first Neisseria gonorrhoeae strain (H041) highly resistant to the expanded-spectrum cephalosporins (ESCs) ceftriaxone and cefixime, which are the last remaining options for first-line gonorrhea treatment, was isolated in Japan. Here, we confirm and characterize a second strain (F89) with high-level cefixime and ceftriaxone resistance which was isolated in France and most likely caused a treatment failure with cefixime. F89 was examined using six species-confirmatory tests, antibiograms (33 antimicrobials), porB sequencing, N. gonorrhoeae multiantigen sequence typing (NG-MAST), multilocus sequence typing (MLST), and sequencing of known gonococcal resistance determinants (penA, mtrR, penB, ponA, and pilQ). F89 was assigned to MLST sequence type 1901 (ST1901) and NG-MAST ST1407, which is a successful gonococcal clone that has spread globally. F89 has high-level resistance to cefixime (MIC = 4 μg/ml) and ceftriaxone (MIC = 1 to 2 μg/ml) and resistance to most other antimicrobials examined. A novel penA mosaic allele (penA-CI), which was penA-XXXIV with an additional A501P alteration in penicillin-binding protein 2, was the primary determinant for high-level ESC resistance, as determined by transformation into a set of recipient strains. N. gonorrhoeae appears to be emerging as a superbug, and in certain circumstances and settings, gonorrhea may become untreatable. Investigations of the biological fitness and enhanced understanding and monitoring of the ESC-resistant clones and their international transmission are required. Enhanced disease control activities, antimicrobial resistance control and surveillance worldwide, and public health response plans for global (and national) perspectives are also crucial. Nevertheless, new treatment strategies and/or drugs and, ideally, a vaccine are essential to develop for efficacious gonorrhea management.
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ClinicalNeisseria gonorrhoeaeIsolates in the United States with Resistance to Azithromycin Possess Mutations in All 23S rRNA Alleles and themtrRCoding Region. Microb Drug Resist 2011; 17:425-7. [DOI: 10.1089/mdr.2010.0199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Gonorrhea, a disease of public health importance, not only leads to high incidence of acute infections and complications but also plays a major role in facilitating human immunodeficiency virus (HIV) acquisition and transmission. One of the major public health needs for gonorrhea control is appropriate, effective treatment. However, treatment options for gonorrhea are diminishing as Neisseria gonorrhoeae have developed resistance to several antimicrobial drugs such as sulfonamides, penicillin, tetracyclines and quinolones. Antimicrobial resistance (AMR) surveillance of N. gonorrhoeae helps establish and maintain the efficacy of standard treatment regimens. AMR surveillance should be continuous to reveal the emergence of new resistant strains, monitor the changing patterns of resistance, and be able to update treatment recommendations so as to assist in disease control. Current treatment guidelines recommend the use of single dose injectable or oral cephalosporins. The emergence and spread of cephalosporin resistant and multi drug resistant N. gonorrhoeae strains, represents a worrying trend that requires monitoring and investigation. Routine clinical laboratories need to be vigilant for the detection of such strains such that strategies for control and prevention could be reviewed and revised from time to time. It will be important to elucidate the genetic mechanisms responsible for decreased susceptibility and future resistance. There is also an urgent need for research of safe, alternative anti-gonococcal compounds that can be administered orally and have effective potency, allowing high therapeutic efficacy (greater than 95.0% cure rate).
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Affiliation(s)
- Manju Bala
- Regional STD Teaching Training and Research Centre, Vardhman Mahavir Medical College and Safdarjang Hospital, New Delhi, India
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Frigo NV, Guchev IA, Sidorenko SV, Lesnaya IN, Solomka VS, Frigo NV, Guchev IA, Sidorenko SV, Lesnaya IN, Solomka VS. Cephalosporins of the third generation for the treatment of gonorrhea. VESTNIK DERMATOLOGII I VENEROLOGII 2011. [DOI: 10.25208/vdv1016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The article presents the data on antibiotic resistance and N. gonorrhoeae mechanisms for developing resistance to
antimicrobial drugs belonging to different pharmacologic groups and applied for causal treatment of gonorrhea. The
article proves the key problem related to the treatment of gonococcal infection in Russia lies in the prevalence of strains
being resistant to most of the antibacterial drugs that used to be applied in the clinical practice on a broad scale and
efficiently. So, cephalosporins of the third generation are presently the only drug type that N. gonorrhoeae remains
sensitive to. Their application ensures the maximum efficacy against the gonococcal infection. According to the presentday
international recommendations complying with the WHO criteria as well as accumulated experience, cefixime, a drug
belonging to cephalosporins of the third generation, can be a drug of choice for the antibacterial therapy of gonorrhea
along with ceftriaxon.
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Is Neisseria gonorrhoeae initiating a future era of untreatable gonorrhea?: detailed characterization of the first strain with high-level resistance to ceftriaxone. Antimicrob Agents Chemother 2011; 55:3538-45. [PMID: 21576437 DOI: 10.1128/aac.00325-11] [Citation(s) in RCA: 491] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recently, the first Neisseria gonorrhoeae strain (H041) that is highly resistant to the extended-spectrum cephalosporin (ESC) ceftriaxone, the last remaining option for empirical first-line treatment, was isolated. We performed a detailed characterization of H041, phenotypically and genetically, to confirm the finding, examine its antimicrobial resistance (AMR), and elucidate the resistance mechanisms. H041 was examined using seven species-confirmatory tests, antibiograms (30 antimicrobials), porB sequencing, N. gonorrhoeae multiantigen sequence typing (NG-MAST), multilocus sequence typing (MLST), and sequencing of ESC resistance determinants (penA, mtrR, penB, ponA, and pilQ). Transformation, using appropriate recipient strains, was performed to confirm the ESC resistance determinants. H041 was assigned to serovar Bpyust, MLST sequence type (ST) ST7363, and the new NG-MAST ST4220. H041 proved highly resistant to ceftriaxone (2 to 4 μg/ml, which is 4- to 8-fold higher than any previously described isolate) and all other cephalosporins, as well as most other antimicrobials tested. A new penA mosaic allele caused the ceftriaxone resistance. In conclusion, N. gonorrhoeae has now shown its ability to also develop ceftriaxone resistance. Although the biological fitness of ceftriaxone resistance in N. gonorrhoeae remains unknown, N. gonorrhoeae may soon become a true superbug, causing untreatable gonorrhea. A reduction in the global gonorrhea burden by enhanced disease control activities, combined with wider strategies for general AMR control and enhanced understanding of the mechanisms of emergence and spread of AMR, which need to be monitored globally, and public health response plans for global (and national) perspectives are important. Ultimately, the development of new drugs for efficacious gonorrhea treatment is necessary.
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Off-target gene regulation mediated by transcriptional repressors of antimicrobial efflux pump genes in Neisseria gonorrhoeae. Antimicrob Agents Chemother 2011; 55:2559-65. [PMID: 21422217 DOI: 10.1128/aac.00010-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNA-binding proteins that control expression of drug efflux pump genes have been termed "local regulators" as their encoding gene is often located adjacent to the gene(s) that they regulate. However, results from recent studies indicate that they can control genes outside efflux pump-encoding loci, which we term as being "off target." For example, the MtrR repressor was initially recognized for its ability to repress transcription of the mtrCDE-encoded efflux pump operon in the strict human pathogen Neisseria gonorrhoeae, but recent results from genetic and microarray studies have shown that it can control expression of nearly 70 genes scattered throughout the chromosome. One of the off-target MtrR-repressed genes is glnA, which encodes glutamine synthetase. Herein, we confirm the capacity of MtrR to repress glnA expression and provide evidence that such repression is due to its ability to negatively influence the binding of a second DNA-binding protein (FarR), which activates glnA. FarR was previously recognized as a transcriptional repressor of the farAB-encoded efflux pump operon. Thus, two DNA-binding proteins previously characterized as repressors of genes encoding efflux pumps that contribute to gonococcal resistance to antimicrobials can act in an opposing manner to modulate expression of a gene involved in basic metabolism.
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Barabote RD, Thekkiniath J, Strauss RE, Vediyappan G, Fralick JA, San Francisco MJ. Xenobiotic efflux in bacteria and fungi: a genomics update. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2011; 77:237-306. [PMID: 21692371 DOI: 10.1002/9780470920541.ch6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Ravi D Barabote
- Department of Plant Sciences, University of California, Davis, California, USA
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Allen VG, Farrell DJ, Rebbapragada A, Tan J, Tijet N, Perusini SJ, Towns L, Lo S, Low DE, Melano RG. Molecular analysis of antimicrobial resistance mechanisms in Neisseria gonorrhoeae isolates from Ontario, Canada. Antimicrob Agents Chemother 2011; 55:703-12. [PMID: 21098249 PMCID: PMC3028768 DOI: 10.1128/aac.00788-10] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 08/06/2010] [Accepted: 11/12/2010] [Indexed: 12/15/2022] Open
Abstract
Surveillance of gonococcal antimicrobial resistance and the molecular characterization of the mechanisms underlying these resistance phenotypes are essential in order to establish correct empirical therapies, as well as to describe the emergence of new mechanisms in local bacterial populations. To address these goals, 149 isolates were collected over a 1-month period (October-November 2008) at the Ontario Public Health Laboratory, Toronto, Canada, and susceptibility profiles (8 antibiotics) were examined. Mutations in previously identified targets or the presence of some enzymes related to resistance (r), nonsusceptibility (ns) (resistant plus intermediate categories), or reduced susceptibility (rs) to the antibiotics tested were also studied. A significant proportion of nonsusceptibility to penicillin (PEN) (89.2%), tetracycline (TET) (72.3%), ciprofloxacin (CIP) (29%), and macrolides (erythromycin [ERY] and azithromycin; 22.3%) was found in these strains. Multidrug resistance was observed in 18.8% of the collection. Although all the strains were susceptible to spectinomycin and extended-spectrum cephalosporins (ESC) (ceftriaxone and cefixime), 9.4% of them displayed reduced susceptibility to extended-spectrum cephalosporins. PBP 2 mosaic structures were found in all of these ESC(rs) isolates. Alterations in the mtrR promoter, MtrR repressor (TET(r), PEN(ns), ESC(rs), and ERY(ns)), porin PIB (TET(r) and PEN(ns)), and ribosomal protein S10 (TET(r)) and double mutations in gyrA and parC quinolone resistance-determining regions (QRDRs) (CIP(r)) were associated with and presumably responsible for the resistance phenotypes observed. This is the first description of ESC(rs) in Canada. The detection of this phenotype indicates a change in the epidemiology of this resistance and highlights the importance of continued surveillance to preserve the last antimicrobial options available.
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Affiliation(s)
- Vanessa G. Allen
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - David J. Farrell
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Anuradha Rebbapragada
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Jingyuan Tan
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Nathalie Tijet
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Stephen J. Perusini
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Lynn Towns
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Stephen Lo
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Donald E. Low
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Roberto G. Melano
- Ontario Agency for Health Protection and Promotion, Public Health Laboratory—Toronto, Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada
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High-level azithromycin resistance occurs in Neisseria gonorrhoeae as a result of a single point mutation in the 23S rRNA genes. Antimicrob Agents Chemother 2010; 54:3812-6. [PMID: 20585125 DOI: 10.1128/aac.00309-10] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High-level azithromycin resistance (AZM-HR), defined as a MIC of > or = 256 mg/liter, emerged in Neisseria gonorrhoeae in the United Kingdom in 2004. To determine the mechanism of this novel phenotype, isolates from the United Kingdom that were AZM-HR (n, 19), moderately AZM resistant (MICs, 2 to 8 mg/liter) (n, 26), or sensitive (MICs, 0.12 to 0.25 mg/liter) (n, 4) were screened for methylase (erm) genes and for mutations in the mtrR promoter region, associated with efflux pump upregulation. All AZM-resistant isolates and 12 sensitive isolates were screened for mutations in domain V of each 23S rRNA allele. All AZM-HR isolates contained the A2059G mutation (Escherichia coli numbering) in three (3 isolates) or four (16 isolates) 23S rRNA alleles. Most (22/26) moderately AZM resistant isolates contained the C2611T mutation in at least 3/4 alleles. The remainder contained four wild-type alleles, as did 8/12 sensitive isolates, while one allele was mutated in the remaining four sensitive isolates. Serial passage of AZM-sensitive colonies on an erythromycin-containing medium selected AZM-HR if the parent strain already contained mutation A2059G in one 23S rRNA allele. The resultant AZM-HR strains contained four mutated alleles. Eight isolates (five moderately AZM resistant and three AZM-HR) contained mutations in the mtrR promoter. No methylase genes were detected. This is the first evidence that AZM-HR in gonococci may result from a single point mutation (A2059G) in the peptidyltransferase loop in domain V of the 23S rRNA gene. Mutation of a single allele is insufficient to confer AZM-HR, but AZM-HR can develop under selection pressure. The description of a novel resistance mechanism will aid in screening for the AZM-HR phenotype.
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Chen PL, Lee HC, Yan JJ, Hsieh YH, Lee NY, Ko NY, Lin CW, Chang CM, Wu CJ, Lee CC, Ko WC. High Prevalence of Mutations in Quinolone-resistance-determining Regions and mtrR Loci in Polyclonal Neisseria gonorrhoeae Isolates at a Tertiary Hospital in Southern Taiwan. J Formos Med Assoc 2010; 109:120-7. [DOI: 10.1016/s0929-6646(10)60032-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 03/06/2009] [Accepted: 06/08/2009] [Indexed: 10/19/2022] Open
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Bishburg E, Bishburg K. Minocycline--an old drug for a new century: emphasis on methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii. Int J Antimicrob Agents 2009; 34:395-401. [PMID: 19665876 DOI: 10.1016/j.ijantimicag.2009.06.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 06/04/2009] [Accepted: 06/23/2009] [Indexed: 10/20/2022]
Abstract
The epidemiology of nosocomial and community-acquired infections has changed in recent years. Methicillin-resistant Staphylococcus aureus (MRSA), especially community-associated MRSA (CA-MRSA), has emerged as a gram-positive organism with an increasing impact in clinical practice. Infections with Acinetobacter baumannii have become a major cause of morbidity and mortality. Minocycline has significant in vitro activity against MRSA and A. baumannii that is comparable with agents currently used against these organisms. The absence of an intravenous (i.v.) minocycline formulation in recent years has limited its use in seriously ill patients infected with these organisms. However, minocycline i.v. has recently been reintroduced to the US market. The objective of this study was to review available information on the chemistry, mechanism of action, in vitro activity, resistance mechanisms, pharmacokinetics, tolerability and efficacy of minocycline against MRSA and A. baumannii. This article provides suggestions for future studies and potential uses of minocycline and is designed to trigger interest in systematic clinical evaluation of minocycline for patients infected with these organisms. In conclusion, minocycline is an old drug that has the potential to become an important part of the armamentarium against emerging infections such as CA-MRSA and A. baumannii. Owing to its promising profile against these clinically important pathogens as well as excellent pharmacokinetic properties, minocycline merits evaluation in serious infections.
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Affiliation(s)
- Eliahu Bishburg
- Division of Infectious Diseases, Beth Israel Medical Center, 201 Lyons Avenue G3, Newark, NJ 07112, USA.
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Simple, rapid, and inexpensive detection of Neisseria gonorrhoeae resistance mechanisms using heat-denatured isolates and SYBR green-based real-time PCR. Antimicrob Agents Chemother 2009; 53:4211-6. [PMID: 19528267 DOI: 10.1128/aac.00385-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria gonorrhoeae has developed resistance to multiple classes of antimicrobials. There is now growing concern that without the availability of appropriate public health strategies to combat this problem, gonorrhea could become untreatable. For this reason, surveillance for gonococcal antimicrobial resistance must be optimal both in terms of obtaining a representative sample of gonococcal isolates and in terms of having the appropriate tools to identify resistance. To aid with this surveillance, molecular tools are increasingly being used. In the present study, we investigated the use of a simple heat denaturation protocol for isolate DNA preparation combined with SYBR green-based real-time PCR for the identification of mutations associated with N. gonorrhoeae antimicrobial resistance. A total of 109 clinical gonococcal isolates were tested by high-resolution melting (HRM) curve analysis for chromosomal mutations associated with gonococcal resistance to beta-lactam antibiotics: a penA 345A insertion, ponA L421P, mtrR G45D, substitutions at positions 120 and 121 in porB1b, and an adenine deletion in the mtrR promoter. An allele-specific PCR assay was also investigated for its ability to detect the adenine deletion in the mtrR promoter. The results were compared to those obtained by DNA sequencing. Our HRM assays provided the accurate discrimination of heat-treated isolates in which the sequence types differed in GC content, including isolates with the penA 345A insertion and the ponA L421P and mtrR G45D mutations. The allele-specific PCR assay accurately identified isolates with the adenine deletion in the mtrR promoter. Heat-denatured DNA combined with SYBR green-based real-time PCR offers a simple, rapid, and inexpensive means of detecting gonococcal resistance mechanisms. These methods may have broader application in the detection of polymorphisms associated with phenotypes of interest.
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Unemo M, Fasth O, Fredlund H, Limnios A, Tapsall J. Phenotypic and genetic characterization of the 2008 WHO Neisseria gonorrhoeae reference strain panel intended for global quality assurance and quality control of gonococcal antimicrobial resistance surveillance for public health purposes. J Antimicrob Chemother 2009; 63:1142-51. [PMID: 19318360 DOI: 10.1093/jac/dkp098] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Emergence and spread of antimicrobial resistance (AMR) in Neisseria gonorrhoeae remain a major global problem and expanded, but valid, AMR surveillance is crucial for public health purposes. The World Health Organization (WHO) Collaborating Centre in Sydney, Australia, continually evaluates N. gonorrhoeae strains used in quality control and assurance aspects of the national, WHO regional and international programmes for AMR surveillance it conducts. Here we phenotypically and genetically characterized the 2008 WHO N. gonorrhoeae reference panel, widely used under existing WHO AMR surveillance protocols. MATERIALS AND METHODS The eight N. gonorrhoeae WHO reference strains were phenotypically characterized by antibiogram, auxotype, serovar and prolyliminopeptidase screening; and genetically with regard to resistance plasmid types, polymorphisms in divergent genetic resistance-mediating loci (n = 9), porB sequencing and N. gonorrhoeae multi-antigen sequence typing. RESULTS The 2008 WHO reference strains represented all the important susceptible and resistant phenotypes, including corresponding resistance genotypes, and the range of resistances currently seen for relevant antimicrobials. Several pertinent additional phenotypic and genotypic markers, for example, epidemiological markers, were also determined. CONCLUSIONS The 2008 WHO N. gonorrhoeae reference strain panel was extensively characterized, which is crucial for the expansion of gonococcal AMR surveillance nationally and internationally. The panel is available through WHO sources for quality assurance and quality control aspects of current phenotypic testing protocols, to allow valid comparison of AMR data derived by divergent methods, and also for the control of present and future molecular assays for AMR detection. Additional WHO reference strains can be included as required by the emergence of additional resistant phenotypes and/or genotypes.
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Affiliation(s)
- Magnus Unemo
- Department of Clinical Microbiology, Orebro University Hospital, Sweden.
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Antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in 2004-2006 in Bangui, Central African Republic; Yaoundé, Cameroon; Antananarivo, Madagascar; and Ho Chi Minh Ville and Nha Trang, Vietnam. Sex Transm Dis 2008; 35:941-5. [PMID: 18724270 DOI: 10.1097/olq.0b013e31818318d8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
GOAL To investigate the in vitro antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in 2004 and 2005 in Bangui, Central African Republic; Yaoundé, Cameroon; Antananarivo, Madagascar; and Ho Chi Minh Ville and Nha Trang, Vietnam. STUDY DESIGN Antimicrobial susceptibility testing was performed by both disk diffusion and agar dilution methods according to Clinical and Laboratory Standards Institute (CLSI) recommendations. Minimum inhibitory concentrations (MICs) to 5 antimicrobials (penicillin G, ceftriaxone, ciprofloxacin, spectinomycin, and tetracycline) were determined when feasible. Penicillinase-producing N. gonorrhoeae (PPNG) was analyzed by the paper acidometric method (nitrocefin test). RESULTS Thirty N. gonorrhoeae isolates from Bangui could be studied, 79 from Yaoundé, 126 from Antananarivo, 56 from Nha Trang, and 126 from Ho Chi Minh Ville in 2004 and 2005. Unfortunately, because of problems of electricity supply, no strains could be recovered for the determination of MICs in Yaoundé, and only 68 strains could be tested in Antananarivo and 121 in Ho Chi Minh Ville. Patterns of resistance were similar in Antananarivo, Bangui, and Yaoundé but different from those observed in Vietnam. Ciprofloxacin was highly effective in Africa, but nearly all strains in Vietnam were resistant to this drug. Overall, ceftriaxon and spectinomycin were the best antibiotics, with one strain resistant to spectinomycin in Antananrivo and one strain resistant to ceftriaxon in Ho Chi Minh Ville. CONCLUSIONS Ciprofloxacin remains highly efficient in Madagascar and Central Africa, ceftriaxone and spectinomycin should be used as the first-line antimicrobial agents in treating gonorrhea in Vietnam.
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MtrR modulates rpoH expression and levels of antimicrobial resistance in Neisseria gonorrhoeae. J Bacteriol 2008; 191:287-97. [PMID: 18978065 DOI: 10.1128/jb.01165-08] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The MtrR transcriptional-regulatory protein is known to repress transcription of the mtrCDE operon, which encodes a multidrug efflux pump possessed by Neisseria gonorrhoeae that is important in the ability of gonococci to resist certain hydrophobic antibiotics, detergents, dyes, and host-derived antimicrobials. In order to determine whether MtrR can exert regulatory action on other gonococcal genes, we performed a whole-genome microarray analysis using total RNA extracted from actively growing broth cultures of isogenic MtrR-positive and MtrR-negative gonococci. We determined that, at a minimum, 69 genes are directly or indirectly subject to MtrR control, with 47 being MtrR repressed and 22 being MtrR activated. rpoH, which encodes the general stress response sigma factor RpoH (sigma 32), was found by DNA-binding studies to be directly repressed by MtrR, as it was found to bind to a DNA sequence upstream of rpoH that included sites within the rpoH promoter. MtrR also repressed the expression of certain RpoH-regulated genes, but this regulation was likely indirect and a reflection of MtrR control of rpoH expression. Inducible expression of MtrR was found to repress rpoH expression and to increase gonococcal susceptibility to hydrogen peroxide (H(2)O(2)) and an antibiotic (erythromycin) recognized by the MtrC-MtrD-MtrE efflux pump system. We propose that, apart from its ability to control the expression of the mtrCDE-encoded efflux pump operon and, as a consequence, levels of gonococcal resistance to host antimicrobials (e.g., antimicrobial peptides) recognized by the efflux pump, the ability of MtrR to regulate the expression levels of rpoH and RpoH-regulated genes also modulates levels of gonococcal susceptibility to H(2)O(2).
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Vernel-Pauillac F, Nandi S, Nicholas RA, Goarant C. Genotyping as a tool for antibiotic resistance surveillance of Neisseria gonorrhoeae in New Caledonia: evidence of a novel genotype associated with reduced penicillin susceptibility. Antimicrob Agents Chemother 2008; 52:3293-300. [PMID: 18591264 PMCID: PMC2533457 DOI: 10.1128/aac.00020-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 02/04/2008] [Accepted: 06/11/2008] [Indexed: 11/20/2022] Open
Abstract
Antibiotic resistance in Neisseria gonorrhoeae continues to be a major concern in public health. Resistance of N. gonorrhoeae bacteria to penicillin G is widespread in most developed countries, which has necessitated a change to newer drugs for treatment of gonococcal infections. Recent reports indicate that resistance to these newer drugs is increasing, highlighting the need for accurate therapeutic recommendations. In some countries or communities, however, N. gonorrhoeae isolates are still susceptible to penicillin, so the use of this antibiotic for single-dose treatments of medically under-resourced patients is beneficial. In order to evaluate the adequacy and sustainability of this treatment approach, we explored the presence and prevalence of chromosomally mediated resistance determinants in N. gonorrhoeae isolates collected from 2005 to 2007 in New Caledonia. We developed two new real-time PCR assays targeting the penB and mtrR determinants, to be used together with a previously described duplex assay targeting the penA and ponA determinants. The results of this study provided evidence that neither the most-common mtrR determinants nor the most-resistance-associated penB alleles are currently circulating in New Caledonia, suggesting that penicillin should still be considered a valuable treatment strategy. Additionally, using our genotyping assay, we observed an unexpected penB genotype at a relatively high frequency that was associated with a decreased susceptibility to penicillin (average MIC, 0.15 mug/ml). Sequencing revealed that this genotype corresponded to an A102S mutation in the penB gene. The molecular tools developed in this study can be used successfully for prospective epidemiological monitoring and surveillance of penicillin susceptibility.
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Affiliation(s)
- Frédérique Vernel-Pauillac
- Institut Pasteur de Nouvelle-Calédonie, Laboratoire de Recherche en Bactériologie, Nouméa Cedex, New Caledonia
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Warner DM, Shafer WM, Jerse AE. Clinically relevant mutations that cause derepression of the Neisseria gonorrhoeae MtrC-MtrD-MtrE Efflux pump system confer different levels of antimicrobial resistance and in vivo fitness. Mol Microbiol 2008; 70:462-78. [PMID: 18761689 DOI: 10.1111/j.1365-2958.2008.06424.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The MtrC-MtrD-MtrE efflux pump system confers resistance to macrolide antibiotics and antimicrobial substances of the host innate defence. Clinical isolates with increased resistance to erythromycin and azithromycin frequently harbour mutations in the mtrR structural gene, which encodes a repressor of the mtrCDE operon, or the mtrR promoter region. The MtrC-MtrD-MtrE system is important for gonococcal survival in the murine genital tract, and derepression of the mtrCDE operon via deletion of mtrR confers increased fitness in vivo. Here we compared isogenic strains with naturally occurring mtrR locus mutations for differences in mtrCDE expression and pump-related phenotypes. Mutations upstream of mtrC, including those within the MtrR binding region and a novel mutation that increases mtrC RNA stability conferred the highest levels of derepression as measured by mtrCDE transcription and resistance to antibiotics, progesterone and antimicrobial peptides. In contrast, mutations within the mtrR coding sequence conferred low to intermediate levels of derepression. In vivo, the mtr mutants were more fit than the wild-type strain, the degree to which paralleled in vitro resistance gradients. These studies establish a hierarchy of mtrR locus mutations with regard to regulation of pump efflux, and suggest selection for more derepressed mutants may occur during mixed infections.
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Affiliation(s)
- Douglas M Warner
- Department of Microbiology and Immunology, F. Edward Hèbert School of Medicine, Uniformed Services University, Bethesda, MD, USA
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85
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Phenotypic and genotypic analyses of Neisseria gonorrhoeae isolates that express frequently recovered PorB PIA variable region types suggest that certain P1a porin sequences confer a selective advantage for urogenital tract infection. Infect Immun 2008; 76:3700-9. [PMID: 18541655 DOI: 10.1128/iai.00265-08] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Typing of the porB variable region (VR) is an epidemiological tool that classifies gonococcal strains based on sequence differences in regions of the porB gene that encode surface-exposed loops. The frequent isolation of certain porB VR types suggests that some porin sequences confer a selective advantage during infection and/or transmission. Alternatively, certain porin types may be markers of strains that are successful due to factors unrelated to porin. In support of the first hypothesis, here we show urogenital tract isolates representing the most common PIA VR types identified in an urban clinic in Baltimore, MD, over a 10-year period belonged to several different clonal types, as determined by pulsed-field gel electrophoresis (PFGE). Serum resistance, which was confirmed by factor H and C4b-binding protein binding studies, was more often associated with gonococcal the most common VR types. In contrast, three porin-independent phenotypes, namely, lactoferrin utilization, beta-lactamase production, and multiple transferable resistance (Mtr), were segregated with the PFGE cluster and not with the VR type. Data combined with another PIA strain collection showed a strong correlation between serum resistance and the most common VR types. A comparison of VR typing hybridization patterns and nucleotide sequences of 12 porB1a genes suggests that certain porin loop 1, 3, 6, and/or 7 sequences may play a role in the serum resistance phenotype. We conclude that some PorB PIA sequences confer a survival or transmission advantage in the urogenital tract, perhaps via increased resistance to complement-mediated killing. The capacity of some porin types to evade a porin-specific adaptive immune response must also be considered.
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86
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Analysis of amino acid sequences of penicillin-binding protein 2 in clinical isolates of Neisseria gonorrhoeae with reduced susceptibility to cefixime and ceftriaxone. J Infect Chemother 2008; 14:195-203. [DOI: 10.1007/s10156-008-0610-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Accepted: 03/04/2008] [Indexed: 10/21/2022]
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87
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Lindberg R, Fredlund H, Nicholas R, Unemo M. Neisseria gonorrhoeae isolates with reduced susceptibility to cefixime and ceftriaxone: association with genetic polymorphisms in penA, mtrR, porB1b, and ponA. Antimicrob Agents Chemother 2007; 51:2117-22. [PMID: 17420216 PMCID: PMC1891421 DOI: 10.1128/aac.01604-06] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 01/15/2007] [Accepted: 03/23/2007] [Indexed: 11/20/2022] Open
Abstract
The recent emergence and transmission of Neisseria gonorrhoeae isolates with reduced susceptibility to expanded-spectrum cephalosporins such as cefixime and ceftriaxone have been reported. The aim of this study was to determine the correlation of different polymorphisms in the penA, mtrR, porB1b (penB), and ponA genes of N. gonorrhoeae with reduced susceptibility to cefixime and ceftriaxone. Eighteen gonococcal isolates with reduced cefixime and ceftriaxone susceptibility (Cef(i)) and two susceptible isolates were characterized using serovar determination, antibiograms, N. gonorrhoeae multiantigen sequence typing (NG-MAST), and sequencing of penA, mtrR, porB1b, and ponA alleles. For the Cef(i) isolates (n = 18), the MICs of cefixime and ceftriaxone ranged between 0.032 to 0.38 mug/ml and 0.064 to 0.125 mug/ml, respectively. These isolates were assigned five different serovars and six divergent NG-MAST sequence types. Eleven isolates (61%) with higher MICs of cefixime and ceftriaxone contained a nearly identical penA mosaic allele and previously described polymorphisms in mtrR (a single nucleotide [A] deletion in the promoter), penB (mutations in porB1b encoding loop 3 of PorB1b), and ponA (ponA1 polymorphism). The remaining seven Cef(i) isolates (39%), which had somewhat lower MICs of cefixime and ceftriaxone, contained an aspartic acid insertion (Asp-345a) in PBP 2 in conjunction with alterations of 4 to 10 amino acid residues in the C-terminal region of the transpeptidase domain of penA. In conclusion, an unambiguous association between penA mosaic alleles, in conjunction with genetic polymorphisms in mtrR, porB1b, and ponA, and greater reduced susceptibility to cefixime and ceftriaxone was identified.
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Affiliation(s)
- Robert Lindberg
- Department of Clinical Microbiology, Orebro University Hospital, SE-701 85 Orebro, Sweden
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88
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Folster JP, Dhulipala V, Nicholas RA, Shafer WM. Differential regulation of ponA and pilMNOPQ expression by the MtrR transcriptional regulatory protein in Neisseria gonorrhoeae. J Bacteriol 2007; 189:4569-77. [PMID: 17483228 PMCID: PMC1913451 DOI: 10.1128/jb.00286-07] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria gonorrhoeae utilizes the mtrCDE-encoded efflux pump system to resist not only host-derived, hydrophobic antimicrobials that bathe mucosal surfaces, which likely aids in its ability to colonize and infect numerous sites within the human host, but also antibiotics that have been used clinically to treat infections. Recently, overexpression of the MtrC-MtrD-MtrE efflux pump was shown to be critically involved in the capacity of gonococci to develop chromosomally mediated resistance to penicillin G, which for over 40 years was used to treat gonococcal infections. Mutations in either the promoter or the coding sequence of the mtrR gene, which encodes a repressor of the efflux pump operon, decrease gonococcal susceptibility to penicillin. We now describe the capacity of MtrR to directly or indirectly influence the expression of two other loci that are involved in gonococcal susceptibility to penicillin: ponA, which encodes penicillin-binding protein 1 (PBP 1), and the pilMNOPQ operon, which encodes components of the type IV pilus secretion system, with PilQ acting as a channel for entry for penicillin. We determined that MtrR increases the expression of ponA directly or indirectly, resulting in increased levels of PBP 1, while repressing the expression of the divergently transcribed pilM gene, the first gene in the pilMNOPQ operon. Taken together with other studies, the results presented herein indicate that transcriptional regulation of gonococcal genes by MtrR is centrally involved in determining levels of gonococcal susceptibility to penicillin and provides a framework for understanding how resistance developed over the years.
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Affiliation(s)
- Jason P Folster
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
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89
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Newman LM, Moran JS, Workowski KA. Update on the management of gonorrhea in adults in the United States. Clin Infect Dis 2007; 44 Suppl 3:S84-101. [PMID: 17342672 DOI: 10.1086/511422] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Gonorrhea, the second most commonly reported notifiable disease, is an important cause of cervicitis, urethritis, and pelvic inflammatory disease. The selection of appropriate therapy for gonorrhea (i.e., safe, highly effective, single dose, and affordable) is complicated by the ability of Neisseria gonorrhoeae to develop resistance to antimicrobial therapies. This article reviews the key questions and data that informed the 2006 gonorrhea treatment recommendations of the Centers for Disease Control and Prevention. Key areas addressed include the criteria used to select effective treatment for gonorrhea, the level of antimicrobial resistance at which changing treatment regimens is recommended, the epidemiology of resistance, and the use of quinolones, cephalosporins, and other classes of antimicrobials for the treatment of uncomplicated gonorrhea.
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Affiliation(s)
- Lori M Newman
- Division of STD Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention (proposed), Atlanta, GA 30333, USA.
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90
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Dillon JAR, Ruben M, Li H, Borthagaray G, Márquez C, Fiorito S, Galarza P, Portilla JL, León L, Agudelo CI, Sanabria OM, Maldonado A, Prabhakar P. Challenges in the control of gonorrhea in South America and the Caribbean: monitoring the development of resistance to antibiotics. Sex Transm Dis 2006; 33:87-95. [PMID: 16432479 DOI: 10.1097/01.olq.0000187231.28812.29] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE : The objective of this study was to ascertain the antimicrobial susceptibility of Neisseria gonorrhoeae isolates from 6 South American and 13 Caribbean countries participating in the Gonococcal Antimicrobial Surveillance Program (GASP) from 1990 to 1999. STUDY : A GASP network of laboratories was launched in the Americas and the Caribbean during the 1990s. Standardized methods and interpretative criteria were established for the isolation of N. gonorrhoeae, strain identification, and determination, and quality control of antimicrobial susceptibility. RESULTS : Two countries (Argentina and Uruguay) maintained continuous surveillance during the study period. Some countries gathered data periodically and several others were unable to initiate antimicrobial surveillance as a result of lack of resources. The percentage of penicillin-resistant N. gonorrhoeae isolated in the region over the decade varied considerably (1.0-11.9% carried chromosomal resistance and 17.9-38.8% produced beta-lactamase) with an overall trend to declining numbers of penicillin-resistant isolates. For tetracycline, 7.4% to 36.3% carried chromosomal resistance, whereas 12.0% to 27.4% carried plasmid-mediated resistance. There were no reports of ciprofloxacin-resistant isolates, although N. gonorrhoeae with decreased susceptibility to ciprofloxacin and azithromycin as well as spectinomycin-resistant isolates were identified in some countries.
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Affiliation(s)
- Jo-Anne R Dillon
- Gonococcal Antimicrobial Surveillance Program (GASP) in the Americas and the Caribbean, Ottawa, Canada.
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91
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Tanaka M, Nakayama H, Huruya K, Konomi I, Irie S, Kanayama A, Saika T, Kobayashi I. 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. Int J Antimicrob Agents 2006; 27:20-6. [PMID: 16318912 DOI: 10.1016/j.ijantimicag.2005.08.021] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Accepted: 08/27/2005] [Indexed: 10/25/2022]
Abstract
A Neisseria gonorrhoeae strain with a reduced susceptibility to ceftriaxone (minimum inhibitory concentration (MIC) = 0.5 microg/mL) was isolated among 398 clinical isolates obtained from 2000-2001 in Fukuoka City, Japan. The N. gonorrhoeae strain was negative for penicillinase production but it showed multidrug resistance against penicillin (MIC = 8 microg/mL), tetracycline (MIC = 4 microg/mL), azithromycin (MIC = 0.5 microg/mL) and ciprofloxacin (MIC = 16 microg/mL). The molecular mechanisms of the multidrug-resistant phenotype in this strain were analysed. Polymerase chain reaction and direct DNA sequencing were performed to identify mutations within the penA, ponA, mtrR, penB, gyrA and parC genes of the gonococcal strain, which thus explain the multidrug-resistant phenotype. The N. gonorrhoeae strain contained a significantly different sequence of the penA gene from that of the ceftriaxone-susceptible strains. Some regions of the transpeptidase domain within this penA gene were closely similar to those found in other Neisseria species such as Neisseria subflava, Neisseria flavescens or Neisseria perflava/sicca. This strain also included a ponA mutation that is associated with high-level resistance to penicillin, mtrR mutations that mediate overexpression of the MtrCDE efflux pump responsible for resistance to hydrophobic agents such as azithromycin, and penB mutations that reduce porin permeability to hydrophilic agents such as tetracycline. Moreover, this strain contained gyrA and parC mutations that confer high-level resistance to ciprofloxacin. These results indicate the emergence of a N. gonorrhoeae strain with reduced susceptibility to ceftriaxone, which also showed a multidrug-resistant phenotype that can be explained by the presence of multiple loci mutations associated with antibiotic resistance.
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Affiliation(s)
- Masatoshi Tanaka
- Department of Urology, School of Medicine, Fukuoka University, Jonan-ku, Japan.
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92
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Rouquette-Loughlin CE, Balthazar JT, Shafer WM. Characterization of the MacA–MacB efflux system in Neisseria gonorrhoeae. J Antimicrob Chemother 2005; 56:856-60. [PMID: 16162665 DOI: 10.1093/jac/dki333] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES A homologue of the MacA-MacB ABC transporter of Escherichia coli, which recognizes and exports macrolides, was identified in Neisseria gonorrhoeae. This study was undertaken to determine whether gonococci could use the MacA-MacB homologue to express decreased susceptibility to macrolides. METHODS Techniques of DNA sequencing, gene cloning and expression of recombinant proteins in E. coli, gene mutation construction, transcriptional analysis and antimicrobial susceptibility testing were used in the study. RESULTS Although the gonococcal MacA-MacB efflux pump enhanced bacterial resistance to macrolides when overexpressed in an E. coli background, its loss in a gonococcal clinical isolate only slightly decreased bacterial resistance to azithromycin and erythromycin. However, a mutation in the -10 sequence of the promoter used in macAB expression enhanced the macrolide resistance of gonococci that produced a defective MtrC-MtrD-MtrE pump, which also recognizes macrolides. CONCLUSIONS The results from this study indicate that gonococci can employ both the MacA-MacB and MtrC-MtrD-MtrE efflux pumps to develop resistance to macrolides, particularly if mutations develop in the promoter that drives transcription of macAB.
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93
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Rouquette-Loughlin CE, Balthazar JT, Hill SA, Shafer WM. Modulation of the mtrCDE-encoded efflux pump gene complex of Neisseria meningitidis due to a Correia element insertion sequence. Mol Microbiol 2005; 54:731-41. [PMID: 15491363 DOI: 10.1111/j.1365-2958.2004.04299.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mtr (multiple transferable resistance) gene complex in Neisseria gonorrhoeae encodes an energy-dependent efflux pump system that is responsible for export of anti-bacterial hydrophobic agents. Expression of the mtrCDE operon in gonococci is negatively regulated by the MtrR protein. Hydrophobic agent resistance mediated by the mtr system is also inducible, which results from an AraC-like protein termed MtrA. In this work, we identified and characterized a pump similar to the gonococcal mtr system in various strains of Neisseria meningitidis. Unlike the situation with gonococci, the mtr system in meningococci is not subject to the MtrR or MtrA regulatory schemes. An analysis of the promoter region of the mtrCDE operon in a panel of meningococcal strains revealed the presence of one or two classes of insertion sequence elements. A 155-159 bp insertion sequence element known as the Correia element, previously identified elsewhere in the gonococcal and meningococcal genomes, was present in the mtrCDE promoter region of all meningococcal strains tested. In addition to the Correia element, a minority of strains had a tandemly linked, intact copy of IS1301. As described previously, a binding site for the integration host factor (IHF) was present at the centre of the Correia element upstream of mtrCDE genes. IHF was found to bind specifically to this site and deletion of the IHF binding site enhanced mtrC transcription. We also identified a post-transcriptional regulation of the mtrCDE transcript by cleavage in the inverted repeat of the Correia element, as previously described by Mazzone et al. [Gene278: 211-222 (2001)] and De Gregorio et al. [Biochim Biophys Acta 1576: 39-44 (2002)]for other Correia element. We conclude that the mtr efflux system in meningococci is subject to transcriptional regulation by IHF and post-transcriptional regulation by cleavage in the inverted repeat of the Correia element.
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94
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Folster JP, Shafer WM. Regulation of mtrF expression in Neisseria gonorrhoeae and its role in high-level antimicrobial resistance. J Bacteriol 2005; 187:3713-20. [PMID: 15901695 PMCID: PMC1112036 DOI: 10.1128/jb.187.11.3713-3720.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 03/02/2005] [Indexed: 11/20/2022] Open
Abstract
The obligate human pathogen Neisseria gonorrhoeae uses the MtrC-MtrD-MtrE efflux pump to resist structurally diverse hydrophobic antimicrobial agents (HAs), some of which bathe mucosal surfaces that become infected during transmission of gonococci. Constitutive high-level HA resistance occurs by the loss of a repressor (MtrR) that negatively controls transcription of the mtrCDE operon. This high-level HA resistance also requires the product of the mtrF gene, which is located downstream and transcriptionally divergent from mtrCDE. MtrF is a putative inner membrane protein, but its role in HA resistance mediated by the MtrC-MtrD-MtrE efflux pump remains to be determined. High-level HA resistance can also be mediated through an induction process that requires enhanced transcription of mtrCDE when gonococci are grown in the presence of a sublethal concentration of Triton X-100. We now report that inactivation of mtrF results in a significant reduction in the induction of HA resistance and that the expression of mtrF is enhanced when gonococci are grown under inducing conditions. However, no effect was observed on the induction of mtrCDE expression in an MtrF-negative strain. The expression of mtrF was repressed by MtrR, the major repressor of mtrCDE expression. In addition to MtrR, another repressor (MpeR) can downregulate the expression of mtrF. Repression of mtrF by MtrR and MpeR was additive, demonstrating that the repressive effects mediated by these regulators are independent processes.
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Affiliation(s)
- Jason P Folster
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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95
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Ramos JL, Martínez-Bueno M, Molina-Henares AJ, Terán W, Watanabe K, Zhang X, Gallegos MT, Brennan R, Tobes R. The TetR family of transcriptional repressors. Microbiol Mol Biol Rev 2005; 69:326-56. [PMID: 15944459 PMCID: PMC1197418 DOI: 10.1128/mmbr.69.2.326-356.2005] [Citation(s) in RCA: 832] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have developed a general profile for the proteins of the TetR family of repressors. The stretch that best defines the profile of this family is made up of 47 amino acid residues that correspond to the helix-turn-helix DNA binding motif and adjacent regions in the three-dimensional structures of TetR, QacR, CprB, and EthR, four family members for which the function and three-dimensional structure are known. We have detected a set of 2,353 nonredundant proteins belonging to this family by screening genome and protein databases with the TetR profile. Proteins of the TetR family have been found in 115 genera of gram-positive, alpha-, beta-, and gamma-proteobacteria, cyanobacteria, and archaea. The set of genes they regulate is known for 85 out of the 2,353 members of the family. These proteins are involved in the transcriptional control of multidrug efflux pumps, pathways for the biosynthesis of antibiotics, response to osmotic stress and toxic chemicals, control of catabolic pathways, differentiation processes, and pathogenicity. The regulatory network in which the family member is involved can be simple, as in TetR (i.e., TetR bound to the target operator represses tetA transcription and is released in the presence of tetracycline), or more complex, involving a series of regulatory cascades in which either the expression of the TetR family member is modulated by another regulator or the TetR family member triggers a cell response to react to environmental insults. Based on what has been learned from the cocrystals of TetR and QacR with their target operators and from their three-dimensional structures in the absence and in the presence of ligands, and based on multialignment analyses of the conserved stretch of 47 amino acids in the 2,353 TetR family members, two groups of residues have been identified. One group includes highly conserved positions involved in the proper orientation of the helix-turn-helix motif and hence seems to play a structural role. The other set of less conserved residues are involved in establishing contacts with the phosphate backbone and target bases in the operator. Information related to the TetR family of regulators has been updated in a database that can be accessed at www.bactregulators.org.
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Affiliation(s)
- Juan L Ramos
- Department of Plant Biochemistry and Molecular and Cellular Biology, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Cientificas, Granada, Spain.
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96
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Abstract
Antibiotic resistance continues to plague antimicrobial chemotherapy of infectious disease. And while true biocide resistance is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are common and the history of antibiotic resistance should not be ignored in the development and use of biocidal agents. Efflux mechanisms of resistance, both drug specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials, with some accommodating both antibiotics and biocides. This latter raises the spectre (as yet generally unrealized) of biocide selection of multiple antibiotic-resistant organisms. Multidrug efflux mechanisms are broadly conserved in bacteria, are almost invariably chromosome-encoded and their expression in many instances results from mutations in regulatory genes. In contrast, drug-specific efflux mechanisms are generally encoded by plasmids and/or other mobile genetic elements (transposons, integrons) that carry additional resistance genes, and so their ready acquisition is compounded by their association with multidrug resistance. While there is some support for the latter efflux systems arising from efflux determinants of self-protection in antibiotic-producing Streptomyces spp. and, thus, intended as drug exporters, increasingly, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, appear not to be intended as drug exporters but as exporters with, perhaps, a variety of other roles in bacterial cells. Still, given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents, for example, less impacted by efflux and in targeting efflux directly with efflux inhibitors.
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Affiliation(s)
- Keith Poole
- Department of Microbiology & Immunology, Queen's University, Kingston, ON, Canada.
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97
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McLean CA, Wang SA, Hoff GL, Dennis LY, Trees DL, Knapp JS, Markowitz LE, Levine WC. The Emergence of Neisseria gonorrhoeae With Decreased Susceptibility to Azithromycin in Kansas City, Missouri, 1999 to 2000. Sex Transm Dis 2004; 31:73-8. [PMID: 14743069 DOI: 10.1097/01.olq.0000109514.91508.fc] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES We describe the first cluster of persons with Neisseria gonorrhoeae with decreased susceptibility to azithromycin (AziDS; minimum inhibitory concentration >/=1.0 microg/mL) in the United States. GOAL The goal of this study was to identify risk factors for AziDS N. gonorrhoeae and to describe isolate microbiology. STUDY DESIGN Persons with AziDS N. gonorrhoeae (cases) were identified in Kansas City, Missouri, through the Gonococcal Isolate Surveillance Project (GISP) in 1999 and expanded surveillance, January 2000 to June 2001. A case-control study using 1999 GISP participants was conducted; control subjects had azithromycin-susceptible N. gonorrhoeae. RESULTS Thirty-three persons with AziDS N. gonorrhoeae were identified. Case patients were older than control patients (median age, 33 years vs. 23 years; P <0.001). Fifty percent of cases and 13% of control subjects had a history of sex with a female commercial sex worker (odds ratio, 7.0; 95% confidence interval, 1.3-36.0); 50% of cases and 4% of control subjects met sex partners on street A (P <0.01). AziDS N. gonorrhoeae isolates were phenotypically and genotypically similar and contained an mtrR gene mutation. CONCLUSIONS With few treatment options remaining, surveillance for antimicrobial-resistant N. gonorrhoeae is increasingly important, especially among persons at high risk.
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Affiliation(s)
- Catherine A McLean
- Division of STD Prevention, Division of AIDS, STD, and TB Laboratory Research Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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98
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Ng LK, Martin I, Lau A. Trends of Chromosomally Mediated Antimicrobial Resistance in Neisseria gonorrhoeae in Canada: 1994–1999. Sex Transm Dis 2003; 30:896-900. [PMID: 14646637 DOI: 10.1097/01.olq.0000099560.11350.1a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES We monitored the trends of chromosomally mediated resistant Neisseria gonorrhoeae (CMRNG) in Canada. Chromosomally resistant N. gonorrhoeae (CMRNG) were defined as having resistance to 3 antibiotics: penicillin (minimum inhibitory concentration [MIC] > or =2.0 mg/L), tetracycline (MIC > or =2.0 mg/L and < or =8.0 mg/L), and erythromycin (MIC > or =2.0 mg/L). GOAL The goal was to provide surveillance data for public health interventions for the control of gonococcal infections. STUDY DESIGN Antibiotic susceptibility tests were performed on N. gonorrhoeae isolates obtained from 1994 to 1999 in Canada. Strains were further characterized by auxotype (A), serovar (S), and plasmid profile (P). RESULTS Between 1994 and 1999, 19.2% of strains were CMRNG, 12.9% had a combined resistance to tetracycline and erythromycin, and 4.7% were resistant to tetracycline. The incidence of ciprofloxacin resistance and azithromycin resistance was 2.3% and 0.8%, respectively. CONCLUSION This survey of N. gonorrhoeae provides strain characterization data and temporal trends of strains in the Canadian population. CMRNG strains are on the rise, and the continual monitoring and characterization of these strains is important for the evaluation of current recommended antibiotic therapies used in Canada.
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Affiliation(s)
- Lai-King Ng
- National Microbial Laboratory, Population and Public Health Branch, Health Canada, Winnipeg, Manitoba, Canada.
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Jerse AE, Sharma ND, Simms AN, Crow ET, Snyder LA, Shafer WM. A gonococcal efflux pump system enhances bacterial survival in a female mouse model of genital tract infection. Infect Immun 2003; 71:5576-82. [PMID: 14500476 PMCID: PMC201053 DOI: 10.1128/iai.71.10.5576-5582.2003] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Active efflux of antimicrobial substances is likely to be an important bacterial defense against inhibitory host factors inherent to different body sites. Two well-characterized multidrug resistance efflux systems (MtrCDE and FarAB-MtrE) exist in Neisseria gonorrhoeae, a bacterial pathogen of the human genital mucosae. In vitro studies suggest that the MtrCDE and FarAB-MtrE efflux systems protect the gonococcus from hydrophobic antimicrobial substances that are likely to be present on mucosal surfaces. Here we report that a functional MtrCDE efflux system, but not a functional FarAB-MtrE system, enhances experimental gonococcal genital tract infection in female mice. Specifically, the recovery of mtrD and mtrE mutants, but not a farB mutant, from mice inoculated with mutant or wild-type gonococci was reduced compared with that of the wild-type strain. Competitive-infection experiments confirmed the survival disadvantage of MtrCDE-deficient gonococci. This report is the first direct evidence that a multidrug resistance efflux system enhances survival of a bacterial pathogen in the genital tract. Additionally, experiments using ovariectomized mice showed that MtrCDE-deficient gonococci were more rapidly cleared from mice that were capable of secreting gonadal hormones. MtrCDE-deficient gonococci were more sensitive to nonphysiological concentrations of progesterone in vitro than were wild-type or FarAB-MtrE-deficient gonococci. These results suggest that progesterone may play an inhibitory role in vivo. However, hormonally regulated factors rather than progesterone itself may be responsible for the more rapid clearance of mtr-deficient gonococci from intact mice.
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Affiliation(s)
- Ann E Jerse
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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Sosa J, Ramirez-Arcos S, Ruben M, Li H, Llanes R, Llop A, Dillon JAR. High percentages of resistance to tetracycline and penicillin and reduced susceptibility to azithromycin characterize the majority of strain types of Neisseria gonorrhoeae isolates in Cuba, 1995-1998. Sex Transm Dis 2003; 30:443-8. [PMID: 12916137 DOI: 10.1097/00007435-200305000-00012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND In many regions the susceptibility of Neisseria gonorrhoeae isolates to antimicrobial agents is rarely tested. The Gonococcal Antimicrobial Surveillance Program (GASP) in Cuba was established as part of a larger regional GASP program to facilitate the collection and reporting of antimicrobial susceptibility data for N gonorrhoeae isolates. GOAL The goal was to retrospectively determine the antimicrobial susceptibility and molecular epidemiology of 91 isolates of N gonorrhoeae isolated from 11 centers in Cuba. STUDY DESIGN Isolates of N gonorrhoeae were collected and presumptively identified from 11 Cuban provincial health centers. They were then forwarded to the National Laboratory of Pathogenic Neisseria Havana for confirmatory identification and were subsequently analyzed at the Center for GASP in Ottawa. Isolates were tested for susceptibility to penicillin, tetracycline, spectinomycin, ceftriaxone, ciprofloxacin, and azithromycin by the agar dilution method. To establish baseline data for molecular epidemiologic profiles, the auxotype (A), serovar (S), plasmid content (P), and TetM type of the isolates were determined. Certain A/S/P classes were further analyzed by pulsed field gel electrophoresis (PFGE). RESULTS High percentages of the 91 N gonorrhoeae isolates were resistant to penicillin (68%) and tetracycline (83.5%), with 56% being penicillinase-producing (PPNG) and 64% carrying plasmid-mediated tetracycline resistance (TRNG; 50% were PP/TRNG). An additional 14% of the isolates carried chromosomal resistance (CMRNG) to either tetracycline or penicillin or both antibiotics. All isolates were susceptible to spectinomycin, ceftriaxone, and ciprofloxacin. However, nine isolates were resistant to azithromycin (MIC, > or = 1.0 microgram/ml), and 43 other isolates displayed reduced susceptibility to this antibiotic (MIC, 0.25-0.5 microgram/ml). Although a total of 21 different A/S classes were identified, most of the isolates (61) belonged to three A/S classes: NR/IA-6 (35 isolates), NR/IB-1 (15 isolates), and P/IA-6 (11 isolates). Thirty-two of 45 PP/TRNG were A/S class NR/IA-6, and nine of the P/IA-6 isolates were TRNG. By contrast, most of A/S class NR/IB-1 (8) were CMRNG. PFGE analysis following digestion with NheI or SpeI further clustered the isolates into separate groups. CONCLUSIONS This study demonstrates high percentages of N gonorrhoeae isolates with penicillin and tetracycline resistance in Cuba. As has been noted in other studies in the Caribbean region and Latin America, resistance and reduced susceptibility to azithromycin are developing as emerging problems. Since penicillin and tetracycline continue to be widely used for the treatment of gonococcal infections in Cuba, this study indicates the importance of antimicrobial susceptibility surveillance so that effective antibiotics may be recommended for treatment of gonococcal infections.
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Affiliation(s)
- Jorge Sosa
- Instituto de Medicina Tropical Pedro Kourí, Havana, Cuba
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