The prevalence and epidemiology of plasmid-mediated penicillin and tetracycline resistance among Neisseria gonorrhoeae isolates in Guangzhou, China, 2002-2012

Whole-genome sequence analysis of high-level penicillin-resistant strains and antimicrobial susceptibility of Neisseria gonorrhoeae clinical isolates from Thailand

Background

The increasing rate of antimicrobial-resistant Neisseria gonorrhoeae poses a considerable public health threat due to the difficulty in treating gonococcal infections. This study examined antimicrobial resistance (AMR) to drugs recommended for gonorrhea treatment between 2015 and 2017, and the AMR determinants and genetic compositions of plasmids in 3 gonococcal strains with high-level penicillin resistance.

Methods

We collected 117 N. gonorrhoeae isolates from patients with gonococcal infections who attended Siriraj Hospital, Bangkok, Thailand, between 2015 and 2017. Minimum inhibitory concentrations (MICs) of penicillin, tetracycline, ciprofloxacin, azithromycin, spectinomycin, cefixime, and ceftriaxone were determined by the agar dilution method. PCR amplification and sequencing of 23S rRNA and mtrR (a negative regulator of MtrCDE efflux pump) were performed. Whole genomes of 3 PPNG strains with high-level penicillin resistance (MIC ≥ 128 μg/ml) were sequenced using Illumina and Nanopore sequencing platforms.

Results

The proportions of N. gonorrhoeae isolates with resistance were 84.6% for penicillin, 91.5% for tetracycline, and 96.6% for ciprofloxacin. All isolates were susceptible to spectinomycin, azithromycin, cefixime, and ceftriaxone. An adenine deletion within a 13 bp inverted repeat sequence in the mtrR promoter and an H105Y mutation in the mtrR coding region were found in the N. gonorrhoeae isolate with the highest azithromycin MIC value (1 μg/ml). Three high-level penicillin-resistant isolates contained nonmosaic type II penA and had mutations in penB and the mtrR coding region. All isolates with high-level penicillin resistance carried the conjugative plasmids with or without the Dutch type tetM determinant, the beta-lactamase plasmid (Rio/Toronto), and the cryptic plasmid.

Conclusions

The gonococcal population in Thailand showed high susceptibility to ceftriaxone and azithromycin, current dual therapy recommended for gonorrhea treatment. As elevated MIC of azithromycin has been observed in 1 strain of N. gonorrhoeae, expanded and enhanced surveillance of antimicrobial susceptibility and study of genetic resistance determinants are essential to improve treatment guidelines.

Tracking Antimicrobial Resistance in Neisseria gonorrhoeae from the Molecular Level Using Endocervical Swabs

OBJECTIVE

The global emergence of drug resistance in Neisseria gonorrhoeae has resulted in the use of a range of antibiotics and is now a public health concern because this pathogen may become untreatable in the future. This study aimed to detect antimicrobial-resistant determinants in N. gonorrhoeae directly from endocervical specimens.

METHODS

Three hundred seven pregnant women were enrolled in this study. Endocervical swabs were collected from consenting women and used for the detection of N. gonorrhoeae. Molecular indicators associated with penicillin, tetracycline, ciprofloxacin, azithromycin, spectinomycin, cefixime, and ceftriaxone resistance were detected by polymerase chain reaction.

RESULTS

Of the 307 women, 24 (7.8%) tested positive for N. gonorrhoeae. The tetM gene carried on the American-type plasmid was shown to be present in all the specimens. Approximately 87.5% of the specimens carried the penicillinase-producing African-type plasmid, and the gyrase A gene carrying the Ser-91 mutation was shown to be present in 37.5% of the specimens. Mutations associated with azithromycin, spectinomycin, cefixime, and ceftriaxone resistance were not detected in the study specimens.

CONCLUSION

The detection of resistance determinants without the need for culture may prove to be more feasible for future epidemiological investigations focused on tracking antimicrobial susceptibility patterns in N. gonorrhoeae.

Neisseria gonorrhoeae Antimicrobial Resistance: Past to Present to Future

Neisseria gonorrhoeae (gonococcus) is a Gram-negative bacterium that causes gonorrhoea-a sexually transmitted disease. This gonococcus has progressively developed resistance to most of the available antimicrobials. Only a few countries around the world have been able to run extensive surveillance programmes on gonococcal infection and antimicrobial resistance, raising a global concern. Thus, this review focuses on the mechanisms of resistance to recommended antimicrobials in the past and present time. The approaches by the scientific community in the development of novel technologies such as whole-genome sequencing to predict antimicrobial resistance, track gonococcal transmission, as well as, introduce new therapeutics like Solithromycin, Zoliflodacin, and Gepotidacin were also discussed.

Association of Neisseria gonorrhoeae Plasmids With Distinct Lineages and The Economic Status of Their Country of Origin

Plasmids are vehicles for horizontal gene transfer between bacteria, and in Neisseria gonorrhoeae plasmids can mediate high-level antimicrobial resistance (AMR). Using genomic and phylogenetic analyses, we show that plasmids are widespread in a collection of 3724 gonococcal isolates from 56 countries, and characterized the conjugative, β-lactamase and cryptic plasmids. We found that variants of the conjugative plasmid (which can mediate tetracycline resistance) and the β-lactamase plasmid expressing TEM-135 are associated with distinct gonococcal lineages. Furthermore, AMR plasmids are significantly more prevalent in gonococci from less wealthy countries, highlighting the need for further studies. More than 94% of gonococci possess the cryptic plasmid, with its absence correlated with the presence of a novel chromosomal type IV secretion system. Our results reveal the extent of plasmid-mediated AMR in the gonococcus, particularly in less wealthy countries, where diagnostic and therapeutic options can be limited, and highlight the risk of their global spread.

Changing antimicrobial susceptibility and molecular characterisation of Neisseria gonorrhoeae isolates in Guangdong, China: in a background of rapidly rising epidemic

The prevalence of Neisseria gonorrhoeae infections has increased rapidly since 2015 in China. Antimicrobial resistance and molecular mobilisation in N. gonorrhoeae are two important factors driving this increasing prevalence. This study explored changes in antimicrobial susceptibility and molecular characteristics of N. gonorrhoeae collected in Guangdong, China (2013-2017). A total of 704 isolates were collected in two cities in Guangdong. MICs of major antimicrobials were determined. Penicillinase-producing N. gonorrhoeae (PPNG) and tetracycline-resistant N. gonorrhoeae (TRNG) were characterised, and N. gonorrhoeae multiantigen sequence typing (NG-MAST) was performed. High resistance to penicillin (68.2%), tetracycline (85.7%) and ciprofloxacin (98.2%) was observed. Spectinomycin, ceftriaxone and azithromycin appeared effective, with susceptibilities of 100%, 96.4% and 90.7%, respectively. Resistance to penicillin decreased significantly from 78.4% to 73.6% and to azithromycin from 11.9% to 3.7%. Total prevalence of PPNG, TRNG and PPNG/TRNG was 25.4%, 33.1% and 13.4%, respectively. Rates of PPNG decreased significantly from 37.3% to 23.9%, TRNG from 50.0% to 31.3%, and PPNG/TRNG from 23.5% to 11.7%. However, the ratio of African-type PPNG increased significantly (18.4% to 64.1%) compared with decreasing Asian-type PPNG (81.6% to 33.3%), and the ratio of American-type TRNG increased significantly (0% to 13.7%) compared with decreasing Dutch-type TRNG (100% to 86.3%). A total of 271 sequence types (STs) were identified by NG-MAST from 380 isolates collected in 2013, 2014 and 2017, with 145 novel STs. African-type PPNG is increasing and replacing Asian-type, and novel STs have emerged. Gonococcal isolates with new genotypes might contribute to the rising gonorrhoea epidemic in this area.

Trends in Antimicrobial Resistance Patterns in Neisseria Gonorrhoeae in Australia and New Zealand: A Meta-analysis and Systematic Review

(1) Background: The widespread development of resistance among Neisseria gonorrhoeae (NG) clinical isolates has been reported by surveillance systems around the world. This meta-analysis estimated the changes in susceptibility patterns among antibiotics under surveillance in Australia and New Zealand. (2) Methods: Articles published in English from 1980-2018, from Australia or New Zealand, that met the selection criteria were included. The meta-analysis was carried out using the R statistical software. (3) Results: In Australia, there has been decreasing susceptibility of gonococcal isolates to selected antimicrobials over time. Azithromycin (Odds Ratio (OR): 0.73; 95% Confidence Interval (CI) 0.64-0.82) and ceftriaxone (OR: 0.69; 95% CI 0.59-0.80) showed decreasing levels of susceptibility each year. Western Australia (OR: 0.76; 95% CI 0.60-0.96) and Victoria (OR: 0.74; 95% CI 0.60-0.90) also had decreasing levels of susceptibility to ceftriaxone over time compared with other states and territories. (4) Conclusions: The results highlight the need for the development of new approaches for managing cases of gonorrhoea. Improved antimicrobial stewardship, enhanced surveillance and contact tracing are needed to identify and respond to changes in antibiotic resistance in a timely manner. Increasing awareness and public health follow-up of cases can help to interrupt the cycle of infection and limit transmission.

Effects of passivators on antibiotic resistance genes and related mechanisms during composting of copper-enriched pig manure

Due to the intensive use of feed additives in livestock farming, animal manure has become a hotspot for antibiotics, heavy metals, and antibiotic resistance genes (ARGs). Unlike antibiotics, heavy metals cannot be degraded during composting and thus could pose a persistent co-selective pressure in the proliferation of antibiotic resistance. Passivators are commonly applied to immobilize metals and improve the safety of compost. However, little is known about the effects of various passivators on ARGs and mobile genetic elements (MGEs) during composting and the underlying mechanisms involved. Thus, three typical passivators (biochar, fly ash, and zeolite) were applied during the composting of copper-enriched pig manure, and their effects on ARGs, copper resistance genes, MGEs, and the bacterial communities were examined. Compared to the control, all passivator treatments reduced the abundances of at least six ARGs (tetC, tetG, tetQ, tetX, sul1, and ermB) by 0.23-1.09 logs and of two MGEs (intI1 and ISCR1) by 26-85% after composting. Biochar and fly ash also significantly reduced the abundances of intI2 and Tn914/1545. In contrast, abundances of copper resistance genes were not reduced by passivators, implying that the decreased co-selective pressure may not be a major contributor to ARG reductions in this study. Procrustes analysis and redundancy analysis demonstrated that shifts in the bacterial community determined the changes in the abundances of ARGs, and the variation in MGEs and DTPA-Cu can also partially explain the ARG variance. Overall, all of three passivators can be used to reduce the health risks associated with ARGs in livestock manure, and biochar performed the best at reducing ARGs and MGEs.

High prevalence of TEM-135 expression from the Asian plasmid in penicillinase-producing Neisseria gonorrhoeae from Hangzhou, China

Penicillinase-producing Neisseria gonorrhoeae (PPNG) expressing the TEM β-lactamase variant TEM-135 are a global public-health concern as this variant requires only a single amino acid substitution to develop into an extended-spectrum β-lactamase. The aim of this study was to investigate the epidemiology of bla_TEM-135 in 505 N. gonorrhoeae isolates from Hangzhou, China, during the periods 2011-2012 and 2015-2017. Investigation by nitrocefin test and mismatch amplification PCR showed that 41.0% (207/505) of the isolates were PPNG, of which 37.2% (77/207) contained the bla_TEM-135 gene. Further PCR-based plasmid typing showed that bla_TEM-135 was predominantly expressed from the Asian plasmid (94%). PPNG isolates consisted of three major clusters, namely Asian plasmid/bla_TEM-135 (34.8%), Asian plasmid/bla_TEM-1 (32.4%) and African plasmid/bla_TEM-1 (28.0%), which showed significant differences in penicillin minimum inhibitory concentrations (MICs) determined by the agar dilution method. Representative isolates were investigated by quantitative real-time PCR (plasmid copy number and bla_TEM gene expression), western blot analysis (TEM levels and TEM stability) and in vivo β-lactamase activity assays to elucidate the cause of the observed differences in penicillin MIC. Overall, isolates of the Asian plasmid/bla_TEM-135 cluster showed the highest β-lactamase activity, which was explained by higher bla_TEM gene expression (Asian versus African plasmid) and higher TEM stability (TEM-135 versus TEM-1). In conclusion, the bla_TEM-135 gene is commonly present on the Asian plasmid in PPNG isolates from Hangzhou. The PPNG isolate cluster containing the Asian plasmid and bla_TEM-135 showed the highest penicillin MICs, which might explain its abundance in the Hangzhou population.

Molecular Antimicrobial Resistance of Neisseria gonorrhoeae in a Moroccan Area

Objectives

To identify the prevalence and the types of Neisseria gonorrhoeae (NG) resistance plasmids-mediated penicillin (PPNG) and tetracycline (TRNG), the ciprofloxacin resistance (CRNG), and related risk factors of each types of resistance.

Methods

The beta-lactamase-producing plasmid types (Africa, Asia, and Toronto), tetM tetracycline resistance plasmid types (America and Dutch), and the determination of the Ser-91 mutation of GyrA were detected by specifics PCRs on 149 diagnosed NG positives samples followed by Hinf1 digestion for tetM and gyrA mutation.

Results

135 (90.1%) samples showed a profile of molecular resistance to at least one antibiotic with predominance of ciprofloxacin resistance. In fact, 36 (24.2%) and 69 (46.3%) cases harbored PPNG and TRNG, respectively, and 116 (77.9%) cases showed the mutation Ser-91 of GyrA (CRNG). From a total of 36 PPNG isolates, the Toronto, Asian, and Toronto/Asian types were detected in 13 (36.1%), 10 (27.8%), and 13 (36.1%) cases, respectively, whereas the African type was not detected. In addition, the American type of TRNG was detected in 92.8% (64/69) of cases, while the Dutch type was detected in 7.2% (5/69) of cases. The association of demographics and clinical variables with NG resistance to ciprofloxacin, penicillin, and tetracycline was studied and the risk factors have been determined.

Conclusion

Resistance to penicillin, tetracycline, and ciprofloxacin among NG samples positives remained at high levels in Morocco as determined by molecular profile. So, the use of molecular tools for NG antimicrobial resistance detection can help in the management and spread limitation of this infection.

Identification of Novel Neisseria gonorrhoeae Lineages Harboring Resistance Plasmids in Coastal Kenya

Background

Africa has the highest incidence of gonorrhea in the world. However, little is known about gonococcal populations in this continent or mechanisms of antimicrobial resistance (AMR).

Methods

Whole-genome sequence data were analyzed from 103 Neisseria gonorrhoeae isolates from 73 patients, mainly men who have sex with men, from coastal Kenya. We annotated loci, defined the core genome, defined mechanisms of AMR, and performed phylogenetic analysis. For patients with multiple episodes of gonorrhea, we determined whether infections occurred with related strains.

Results

We identified 3 clusters of isolates that are phylogenetically distinct from isolates found elsewhere. Plasmids were virtually ubiquitous: pTetM and pblaTEM were found in 97%, and 55% of isolates, respectively. This was associated with high doxycycline use for undiagnosed sexually transmitted infections. Twenty-three percent of multiple episodes of gonorrhea in the same individual were caused by a related strain, suggesting inadequate treatment or reinfection.

Conclusions

The prevalence of plasmid-mediated AMR in Kenyan gonococci contrasts with that in wealthy countries, where AMR is largely chromosomally mediated. Antimicrobials have a profound effect on the maintenance of lineages harboring plasmids. Doxycycline can select for tetracycline and penicillin resistance, through plasmid cooperation. Understanding the mechanisms of AMR in high-risk groups is required to inform treatment strategies.

Determining the in vitro susceptibility of Neisseria gonorrhoeae isolates from 8 cities in Guangdong Province through an improved microdilution method

A microdilution method for the antibiotic susceptibility testing of Neisseria gonorrhoeae was established and improved, and the antibiotic resistance of N. gonorrhoeae samples isolated from 8 cities of Guangdong in 2016 was determined. The improved microdilution method was compared with the agar dilution method recommend by the World Health Organization (WHO) Western Pacific Region by testing the susceptibility of 100 clinical N. gonorrhoeae isolates. The essential agreement (EA), categorical agreement (CA), very major error (VME), major error (ME), and minor error (MIE) levels of the two methods were analyzed; the acceptable performance rates were measured as follows: ≥90% for EA or CA, ≤3% for VME or ME, and ≤7% for MIE. The EA, CA, VME, ME, and MIE of each method for 7 antibiotics, penicillin, tetracycline, ciprofloxacin, spectinomycin, ceftriaxone, cefixime, and azithromycin, were 96%-100%, 94%-100%, 0%-3%, 0%-2%, and 0%-6%, respectively. The Wilcoxon signed-rank test results indicated 94%-100% agreement between the 2 methods after excluding off-scale values (P > 0.05). The susceptibility of 634 N. gonorrhoeae strains to the 7 antibiotics above were tested through the microdilution method. The resistant rates of the isolates against ciprofloxacin, tetracycline, penicillin, and azithromycin were 99.8%, 88.3%, 53.8%, and 11%, and the percentages of the isolates with decreased susceptibility to ceftriaxone (minimum inhibitory concentration [MIC] ≥0.125 μg/mL) and cefixime (MIC ≥0.25 μg/mL) were 2.1% and 12%, respectively, in Guangdong. Among 8 cities, Shenzhen had the highest rates of resistance against penicillin (77.8%) and decreased susceptibility against ceftriaxone (5.6%). Zhuhai had the highest rates of decreased susceptibility against cefixime (30.1%), and Jiangmen had the highest azithromycin-resistant isolates (16.8%). The findings from this study indicated that the improved microdilution method is an alternative for testing the antimicrobial susceptibility of N. gonorrhoeae. The resistance rates of N. gonorrhoeae against penicillin, tetracycline, and ciprofloxacin were high. While ceftriaxone, cefixime, and spectinomycin remained effective against N. gonorrhoeae, their effectiveness seemed to be decreasing over time. Azithromycin therapy requires timely susceptibility test results.

Molecular Characterization of Penicillinase-Producing Neisseria gonorrhoeae Isolated in Two Time Periods, 2003-2004 and 2014-2015, in Italy

The emergence of antibiotic resistant strains poses a great concern for gonorrhea treatment. The aim of this study was to characterize penicillinase-producing Neisseria gonorrhoeae (PPNG) isolates collected in Italy in two time frames, 2003-2004 and 2014-2015. A total of 80 PPNG were characterized for the bla_TEM gene variant and the plasmid type. Furthermore, gonococci were typed using Neisseria gonorrhoeae multiantigen sequence typing. Antibiotic susceptibility assay was performed for penicillin, ciprofloxacin, ceftriaxone, and spectinomycin by Etest and minimum inhibitory concentration (MIC) test strip methods. The β-lactamase production was detected using nitrocefin test. Among PPNG isolates, four bla_TEM alleles were identified as follows: bla_TEM-1, bla_TEM-228, bla_TEMP14S, and bla_TEM-135. The African plasmid possessed the bla_TEM-1, bla_TEM-228, and bla_TEMP14S, whereas bla_TEM-135 was identified in Toronto/Rio and Asian plasmids. The percentage of isolates with the bla_TEM-1-carrying African plasmid increased from 42.5% in 2003-2004 to 55% in 2014-2015; conversely, the isolates with bla_TEM-135-carrying Toronto/Rio plasmid decreased from 57.5% to 35%. Among the isolates carrying the Toronto/Rio plasmids possessing bla_TEM-135, sequence type (ST)661 and ST5624 were found to be the predominant STs in both periods 2003-2004 and 2014-2015, respectively. More than half of the PPNG isolates were resistant to ciprofloxacin. Increase in the isolates carrying the African plasmid possessing bla_TEM-1 and a parallel decrease of the bla_TEM-135-carrying Toronto/Rio plasmid was observed. Moreover, PPNG isolate harbored Toronto/Rio plasmid with bla_TEM-135 belonged mainly to two major STs (ST661 and ST5624). Given the possible role of a mutated bla_TEM gene as an additional mechanism to extended spectrum β-lactamase resistance, it is crucial to monitor gonococci carrying these resistance genes.

Surveillance of Antibiotic Susceptibility Patterns of Neisseria gonorrhoeae from 2013 to 2015 in Guangxi Province, China

Neisseria gonorrhoeae is a sexually transmitted pathogen highly prevalent worldwide with an increasing trend of resistance to antimicrobial treatment. We conducted this study to trace the susceptibility of N. gonorrhoeae to penicillin (PC), spectinomycin (SPCM), ciprofloxacin (CPFX), azithromycin (AZM), cefixime (CFIX), and ceftriaxone (CTRX) in Guangxi province. In total, 303 N. gonorrhoeae isolates were obtained from patients infected with N. gonorrhoeae in 6 cities in Guangxi during 2013-2015, and the antibiotic susceptibility patterns were analyzed by an agar dilution assay. The results showed that N. gonorrhoeae was susceptible to treatment with cephalosporins, including CTRX (99.7% of isolates), CFIX (99%), SPCM (100%), and AZM (96.4%), and this is the first report of antibiotic susceptibility for AZM surveillance of N. gonorrhoeae in Guangxi. Penicillinase-producing N. gonorrhoeae (PPNG) isolates increased in prevalence from 37% in 2013 to 64% in 2015 (P = 0.068), and tetracycline-resistant N. gonorrhoeae (TRNG) prevalence increased from 23% in 2013 to 44% in 2015 (P = 0.071). High resistance of N. gonorrhoeae to PC was associated with infection in patients at ages 25 to 30 years (P ＜ 0.05), whereas PPNG positivity (P ＜ 0.01), and TRNG positivity were risk factors for CPFX resistance (P = 0.0407). Our study provides plausible evidence for therapeutic strategies and N. gonorrhoeae infection control and prevention in Guangxi, China.

Draft Genome Sequence of Neisseria gonorrhoeae Strain NG_869 with Penicillin, Tetracycline and Ciprofloxacin Resistance Determinants Isolated from Malaysia

Gonorrhea is a sexually transmitted infection caused by Neisseria gonorrhoeae and the increasing reports of multidrug-resistant gonococcal isolates are a global public health care concern. Herein, we report the genome sequence of N. gonorrhoeae strain NG_869 isolated from Malaysia which may provide insights into the drug resistance determinants in gonococcal bacteria.