Azithromycin Susceptibility Among Neisseria gonorrhoeae Isolates and Seasonal Macrolide Use.
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ABSTRACT:
SUBMITTER: Olesen SW
PROVIDER: S-EPMC6350947 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Neisseria gonorrhoeae multilocus sequence type (ST) 9363 core-genogroup isolates have been associated with reduced azithromycin susceptibility (AZMrs) and show evidence of clonal expansion in the United States. Here, we analyze a global collection of ST-9363 core-genogroup genomes to shed light on the emergence and dissemination of this strain. The global population structure of ST-9363 core-genogroup falls into three lineages: Basal, European, and North American; with 32 clades within all lineages. Although, ST-9363 core-genogroup is inferred to have originated from Asia in the mid-19th century; we estimate the three modern lineages emerged from Europe in the late 1970s to early 1980s. The European lineage appears to have emerged and expanded from around 1986 to 1998, spreading into North America and Oceania in the mid-2000s with multiple introductions, along with multiple secondary reintroductions into Europe. Our results suggest two separate acquisition events of mosaic mtrR and mtrR promoter alleles: first during 2009-2011 and again during the 2012-2013 time, facilitating the clonal expansion of this core-genogroup with AZMrs in the United States. By tracking phylodynamic evolutionary trajectories of clades that share distinct demography as well as population-based genomic statistics, we demonstrate how recombination and selective pressures in the mtrCDE efflux operon granted a fitness advantage to establish ST-9363 as a successful gonococcal lineage in the United States and elsewhere. Although it is difficult to pinpoint the exact timing and emergence of this young core-genogroup, it remains critically important to continue monitoring it, as it could acquire additional resistance markers.
| S-EPMC8778598 | biostudies-literature
Project description:During 2016, eight Neisseria gonorrhoeae isolates from 7 patients in Hawaii were resistant to azithromycin; 5 had decreased in vitro susceptibility to ceftriaxone. Genomic analysis demonstrated a distinct phylogenetic clade when compared with local contemporary strains. Continued evolution and widespread transmission of these strains might challenge the effectiveness of current therapeutic options.
| S-EPMC5403062 | biostudies-literature
Project description:In 2016, the proportion of Neisseria gonorrhoeae isolates with reduced susceptibility to azithromycin rose to 3.6%. A phylogenetic analysis of 334 N. gonorrhoeae isolates collected in 2016 revealed a single, geographically diverse lineage of isolates with MICs of 2 to 16??g/ml that carried a mosaic-like mtr locus, whereas the majority of isolates with MICs of??16??g/ml appeared sporadically and carried 23S rRNA mutations. Continued molecular surveillance of N. gonorrhoeae isolates will identify new resistance mechanisms.
| S-EPMC7179607 | biostudies-literature
Project description:Background:The number of cases of gonorrhoea in the USA and worldwide caused by Neisseria gonorrhoeae is increasing (555 608 reported US cases in 2017, and 87 million cases worldwide in 2016). Many countries report declining in vitro susceptibility of azithromycin, which is a concern because azithromycin and ceftriaxone are the recommended dual treatment in many countries. We aimed to identify strain types associated with decreased susceptibility to azithromycin. Methods:We did a genomic analysis of N gonorrhoeae isolates obtained by the US Gonococcal Isolate Surveillance Project. Isolates were whole-genome sequenced based on decreased susceptibility to azithromycin (minimal inhibitory concentration [MIC] ?2 ?g/mL, using agar dilution antibiotic susceptibility testing) and geographical representation. Bioinformatic analyses established genomic diversity, strain population dynamics, and antimicrobial resistance profiles. Findings:410 isolates were sorted into more than 20 unique phylogenetic clades. One predominant persistent clade (consisting of 97 isolates) included the most isolates with azithromycin MICs of 2 ?g/mL or higher (61 of 97 [63%] vs 59 of 311 [19%]; p<0·0001) and carried a mosaic mtr (multiple transferable resistance) locus (68 of 97 [70%] vs two of 313 [1%]; p<0·0001). Of the remaining 313 isolates, 57 (18%) had decreased susceptibility to azithromycin (MIC ?4 ?g/mL), which was attributed to 23S rRNA variants (56 of 57 [98%]) and formed phylogenetically diverse clades, showing various levels of clonal expansion. Interpretation:Reduced azithromycin susceptibility was associated with expanding and persistent clades harbouring two well described resistance mechanisms, mosaic mtr locus and 23S rRNA variants. Understanding the role of recombination, particularly within the mtr locus, on the fitness and expansion of strains with decreased susceptibility has important implications for the public health response to minimise gonorrhoea transmission. Funding:US Centers for Disease Control and Prevention (CDC), CDC Combating Antibiotic Resistant Bacteria initiative, Oak Ridge Institute for Science Education, US Department of Energy/CDC/Emory University, National Institutes of Health, and Biomedical Laboratory Research and Development Service of the US Department of Veterans Affairs.
| S-EPMC7527259 | biostudies-literature
Project description:Azithromycin-nonsusceptible Neisseria gonorrhoeae strains are an emerging global public health threat. During 2015-2018, the prevalence of azithromycin-nonsusceptible gonococcal infection increased significantly in Argentina. To investigate the genomic epidemiology and resistance mechanisms of these strains, we sequenced 96 nonsusceptible isolates collected in Argentina during 2005-2019. Phylogenomic analysis revealed 2 main clades, which were characterized by a limited geographic distribution, circulating during January 2015-November 2019. These clades included the internationally spreading multilocus sequence types (STs) 1580 and 9363. The ST1580 isolates, which had MICs of 2-4 μg/mL, had mutations in the 23S rRNA. The ST9363 isolates, which had MICs of 2-4 or >256 μg/mL, had mutations in the 23S rRNA, a mosaic mtr locus, or both. Identifying the geographic dissemination and characteristics of these predominant clones will guide public health policies to control the spread of azithromycin-nonsusceptible N. gonorrhoeae in Argentina.
| S-EPMC8386799 | biostudies-literature
Project description: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 ?g/ml, and the MIC90 was 0.5 ?g/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 ?g/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.
| S-EPMC4335827 | biostudies-other
Project description:The growing multidrug-resistant Neisseria gonorrhoeae is a serious global threat to gonococcal therapy. During 2017-2018, we identified a rare multidrug-resistant (ceftriaxone and azithromycin) strain (GC250) and four strains (GC185, GC195, GC196 and GC249) with both resistance to ceftriaxone and decreased susceptibility to azithromycin. All strains belonged to NG-STAR ST1143, including the mosaic penA-60.001, which is closely related to ceftriaxone resistance. The characterization of antimicrobial resistance (AMR) determinants and phylogenetic analysis showed these five strains were closely related to internationally spreading ceftriaxone-resistant N. gonorrhoeae FC428, but with higher azithromycin MIC. Findings here demonstrated that this clone not only initiated clonal expansion in China, but acquired azithromycin resistance.
| S-EPMC6830194 | biostudies-literature
Project description:Fifty-six azithromycin-resistant (MICs, 2.0 to 4.0 micro g/ml) Neisseria gonorrhoeae strains with cross-resistance to erythromycin (MICs, 2.0 to 64.0 micro g/ml), isolated in Canada between 1997 and 1999, were characterized, and their mechanisms of azithromycin resistance were determined. Most (58.9%) of them belonged to auxotype-serotype class NR/IB-03, with a 2.6-mDa plasmid. Based on resistance to crystal violet (MICs >or= 1 micro g/ml), 96.4% of these macrolide-resistant strains appeared to have increased efflux. Nine of the eleven strains selected for further characterization were found to have a promoter region mtrR mutation, a single-base-pair (A) deletion in the 13-bp inverted repeat, which is believed to cause overexpression of the mtrCDE-encoded efflux pump. The two remaining macrolide-resistant strains (erythromycin MIC, 64.0 micro g/ml; azithromycin MIC, 4.0 micro g/ml), which did not have the mutation in the mtrR promoter region, were found to have a C2611T mutation (Escherichia coli numbering) in the peptidyltransferase loop in domain V of the 23S rRNA alleles. Although mutations in domain V of 23S rRNA alleles had been reported in other bacteria, including E. coli, Streptococcus pneumoniae, and Helicobacter pylori, this is the first observation of these mutations associated with macrolide resistance in N. gonorrhoeae.
| S-EPMC127397 | biostudies-literature
Project description:Antimicrobial resistance (AMR) and genetic determinants of resistance of N. gonorrhoeae isolates from Hefei, China, were characterized adding a breadth of information to the molecular epidemiology of gonococcal resistance in China.126 N. gonorrhoeae isolates from a hospital clinic in Hefei, were collected between January, 2014, and November, 2015. The minimum inhibitory concentration (MIC) of N. gonorrhoeae isolates for seven antimicrobials were determined by the agar dilution method. Isolates were tested for mutations in penA and mtrR genes and 23S rRNA, and also genotyped using N. gonorrhoeae multi-antigen sequence typing (NG-MAST).All N. gonorrhoeae isolates were resistant to ciprofloxacin; 81.7% (103/126) to tetracycline and 73.8% (93/126) to penicillin. 39.7% (50/126) of isolates were penicillinase producing N. gonorrhoeae (PPNG), 31.7% (40/126) were tetracycline resistant N. gonorrhoeae (TRNG) and 28.6% (36/126) were resistant to azithromycin. While not fully resistant to extended spectrum cephalosporins (ESCs), a total of 14 isolates (11.1%) displayed decreased susceptibility to ceftriaxone (MIC ? 0.125 mg/L, n = 10), cefixime (MIC ? 0. 25 mg/L, n = 1) or to both ESCs (n = 3). penA mosaic alleles XXXV were found in all isolates that harbored decreased susceptibility to cefixime, except for one. Four mutations were found in mtrR genes and mutations A2143G and C2599T were identified in 23S rRNA. No isolates were resistant to spectinomycin. Gonococcal isolates were distributed into diverse NG-MAST sequence types (STs); 86 separate STs were identified.N. gonorrhoeae isolates from Hefei during 2014-2015, displayed high levels of resistance to antimicrobials that had been recommended previously for treatment of gonorrhea, e.g., penicillin, tetracycline and ciprofloxacin. The prevalence of resistance to azithromycin was also high (28.6%). No isolates were found to be fully resistant to spectinomycin, ceftriaxone or cefixime; however, 11.1% isolates, overall, had decreased susceptibility to ESCs.
| S-EPMC5445337 | biostudies-literature
Project description:With the aim to elucidate gonococcal antimicrobial resistance (AMR)-risk factors, we undertook a retrospective analysis of the molecular epidemiology and AMR of 104 Neisseria gonorrhoeae isolates from clinical samples (urethra, rectum, pharynx and cervix) of 94 individuals attending a sexually transmitted infection clinic in Madrid (Spain) from July to October 2016, and explored potential links with socio-demographic, behavioural and clinical factors of patients. Antimicrobial susceptibility was determined by E-tests, and isolates were characterised by N. gonorrhoeae multi-antigen sequence typing. Penicillin resistance was recorded for 15.4% of isolates, and most were susceptible to tetracycline, cefixime and azithromycin; a high incidence of ciprofloxacin resistance (~40%) was found. Isolates were grouped into 51 different sequence types (STs) and 10 genogroups (G), with G2400, ST5441, ST2318, ST12547 and G2992 being the most prevalent. A significant association (P = 0.015) was evident between HIV-positive MSM individuals and having a ciprofloxacin-resistant strain. Likewise, a strong association (P = 0.047) was found between patient age of MSM and carriage of isolates expressing decreased susceptibility to azithromycin. A decrease in the incidence of AMR gonococcal strains and a change in the strain populations previously reported from other parts of Spain were observed. Of note, the prevalent multi-drug resistant genogroup G1407 was represented by only three strains in our study, while the pan-susceptible clones such as ST5441, and ST2318, associated with extragenital body sites were the most prevalent.
| S-EPMC6805738 | biostudies-literature