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Background Neisseria gonorrhoeae antibiotic resistance surveillance is important to maintain adequate treatment. We analysed 2007-15 data from the Gonococcal Resistance to Antimicrobials Surveillance (GRAS), which currently includes 19 of 25 sexually transmitted infection (STI) centres in the Netherlands. Methods : From each patient with a gonorrhoea culture, the minimum inhibitory concentration (MIC) for several antibiotics was determined. Time trends were assessed by geometric means and linear regression of logarithmic MIC. Determinants for decreased susceptibility to ceftriaxone (MIC > 0.032 mg/L) and resistance to cefotaxime (MIC > 0.125 mg/L) and azithromycin (MIC > 0.5 mg/L) were assessed using stratified logistic regression. Results : 11,768 isolates were analysed. No ceftriaxone resistance was found. In 2015, 27 of 1,425 isolates (1.9%) were resistant to cefotaxime and 176 of 1,623 (10.9%) to azithromycin. Ceftriaxone susceptibility showed no trend (p = 0.96) during the study period, but cefotaxime MIC decreased (p < 0.0001) and azithromycin MIC increased (p < 0.0001) significantly. Concerning ceftriaxone, isolates of men who have sex with men (MSM) from 2013 (p = 0.0005) and 2014 (p = 0.0004) were significantly associated with decreased susceptibility. Significant determinants for cefotaxime resistance were having ≥ 6 partners for women (p = 0.0006). For azithromycin, isolates from MSM collected in 2012 (p = 0.0035), 2013 (p = 0.012), and 2014 (p = 0.013), or from non-Dutch (p < 0.0001) or older (≥ 35 years; p = 0.01) MSM were significantly associated with susceptibility. Resistance in heterosexual men was significantly associated with being ≥ 25 years-old (p = 0.0049) or having 3-5 partners (p = 0.01). Conclusions: No ceftriaxone resistance was found, but azithromycin MIC increased in 2007-15. Resistance determinants could help with focused intervention strategies.

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the scientific impact and the possibility of detecting outbreaks may be amplified by merging the AMR surveillance database with databases from selected pathogen-based surveillance programmes containing patient data and genotypic typing data.

Background: In response to the rising threat of resistance to first-line antibiotics for gonorrhea, international guidelines recommend dual antimicrobial therapy. However, some countries continue to recommend monotherapy. We assess the cost-effectiveness of dual therapy with ceftriaxone and azithromycin compared with monotherapy with ceftriaxone, for control of gonorrhea among men who have sex with men in the Netherlands., Methods: We developed a transmission model and calculated the numbers of new gonorrhea infections, consultations at health care specialists, tests, and antibiotic doses. With these numbers, we calculated costs and quality-adjusted life-years (QALY) with each treatment; and the incremental cost-effectiveness ratio (ICER) of dual therapy compared to monotherapy. The impact of gonorrhea on human immunodeficiency virus transmission was not included in the model., Results: In the absence of initial resistance, dual therapy can delay the spread of ceftriaxone resistance by at least 15 years, compared to monotherapy. In the beginning, when there is no resistance, dual therapy results in high additional costs, without any QALY gains. When resistance spreads over time, the additional costs of dual therapy decline, the gained QALYs increase, the ICER drops off and, after 50 years, falls below &OV0556;20,000 per QALY gained. If azithromycin resistance is initially prevalent, resistance to the first-line treatment rises almost equally fast with both treatment strategies and the ICER remains extremely high., Conclusions: Compared with ceftriaxone monotherapy, dual therapy with ceftriaxone and azithromycin can considerably delay the spread of ceftriaxone resistance, but may only be cost-effective in the long run and in the absence of initial resistance.

Gonorrhoea is one of the most common sexually transmitted infections. The control of gonorrhoea is extremely challenging because of the repeated development of resistance to the antibiotics used for its treatment. We explored different strategies to control the spread of antimicrobial resistance and prevent increases in gonorrhoea prevalence. We used a mathematical model that describes gonorrhoea transmission among men who have sex with men and distinguishes gonorrhoea strains sensitive or resistant to three antibiotics. We investigated the impact of combination therapy, switching first-line antibiotics according to resistance thresholds, and other control efforts (reduced sexual risk behaviour, increased treatment rate). Combination therapy can delay the spread of resistance better than using the 5% resistance threshold. Increased treatment rates, expected to enhance gonorrhoea control, may reduce gonorrhoea prevalence only in the short term, but could lead to more resistance and higher prevalence in the long term. Re-treatment of resistant cases with alternative antibiotics can substantially delay the spread of resistance. In conclusion, combination therapy and re-treatment of resistant cases with alternative antibiotics could be the most effective strategies to prevent increases in gonorrhoea prevalence due to antimicrobial resistance.

Purpose: Understanding which pathogens are associated with clinical manifestation of community-acquired pneumonia (CAP) is important to optimise treatment. We performed a study on the aetiology of CAP and assessed possible implications for patient management in the Netherlands., Methods: Patients with CAP attending the emergency department of a general hospital were invited to participate in the study. We used an extensive combination of microbiological techniques to determine recent infection with respiratory pathogens. Furthermore, we collected data on clinical parameters and potential risk factors., Results: From November 2007 through January 2010, 339 patients were included. Single bacterial infection was found in 39% of these patients, single viral infection in 12%, and mixed bacterial-viral infection in 11%. Streptococcus pneumoniae was the most frequently identified pathogen (22%; n=74). Infection with atypical bacteria was detected in 69 (20%) of the patients., Conclusion: Initial empirical antibiotics should be effective against S. pneumoniae, the most common pathogen identified in CAP patients. The large proportion of patients with infection with atypical bacteria points to the need for improved diagnostic algorithms including atypical bacteria, especially since these atypical bacteria are not covered by the first-choice antibiotic treatment according to the recently revised Dutch guidelines on the management of CAP.

Seventeen laboratories participated in a cooperative study to validate the regional susceptibility testing of Neisseria gonorrhoeae in The Netherlands. International reference strains were distributed. Each laboratory determined the MICs of ciprofloxacin, penicillin, and tetracycline, for each strain by Etest. To explore a more transparent assessment of quality and comparability, a statistical regression model was fitted to the data that accounted for the censoring of the MICs. The mean MICs found by all of the laboratories except three were closer than one 2-fold dilution step to the overall mean, and the mean MICs of each antimicrobial agent were close to the MICs for the international reference strains. This approach provided an efficient tool to analyze the performance of the Dutch decentralized gonococcal resistance monitoring system and confirmed good and comparable standards.

Current test-of-cure practice in patients with Chlamydia trachomatis (Ct) infection is to confirm cure with a single test taken at least 3 weeks after treatment. Effectiveness of single-time-point testing however lacks a scientific evidence basis and the high sensitivity of laboratory assays nowadays in use for this purpose may compromise the clinical significance of their results. Prospectively following 59 treated Ct infections, administering care as usual, the presence of Ct plasmid DNA and rRNA was systematically assessed by multiple time-sequential measurements, i.e. on 18 samples taken per patient during 8 weeks following treatment with a single dose of 1000 mg Azythromycin. A high proportion (42%) of Ct infections tested positive on at least one of the samples taken after 3 weeks. Patients' test results showed substantial inter-individual and intra-individual variation over time and by type of NAAT used. We demonstrated frequent intermittent positive patterns in Ct test results over time, and strongly argue against current test-of-cure practice.

Introduction: Rapid development of Neisseria gonorrhoeae resistance to several antibiotics in recent years threatens treatment and prevention. Targeted surveillance of new resistance patterns and insight into networks and determinants are essential to control this trend., Methods: Since the Gonococcal Resistance to Antimicrobials Surveillance (GRAS) project was implemented within the Dutch national sexually transmitted infection (STI) surveillance network in July 2006, participating STI centres have collected a culture from each gonorrhoea patient. Isolates were tested for susceptibility to penicillin, tetracycline, ciprofloxacin and cefotaxime using Etest. Logistic regression was used to determine risk factors for ciprofloxacin resistance., Results: Between July 2006 and July 2008, prevalence of resistance to penicillin was 10%, to tetracycline 22% and to ciprofloxacin 42%. Resistance to cefotaxime was not found, although minimum inhibitory concentrations higher than 0.125 mg/l drifted upward (p<0.05). Ciprofloxacin resistance rose from 35% in 2006 to 46% in 2008 (p<0.05), despite 2003 guidelines naming cefotaxime as first-choice therapy. In men, ciprofloxacin resistance was higher in men having sex with men (MSM) than in heterosexual men (adjusted OR 2.0, 95% CI : 1.5 to 2.6). In women, it was higher in commercial sex workers (adjusted OR 25.0, 95% CI 7.7 to 78.2) and women aged over 35 years (adjusted OR 8.2, 95% CI 3.0 to 22.7) than in other women., Conclusion: Ciprofloxacin resistance in The Netherlands is increasing, and is particularly found in MSM, older women, and female sex workers. No resistance to current first-choice therapy was found, but alertness to potential clinical failures is essential. By merging epidemiological and microbiological data in GRAS, specific high-risk transmission groups can be identified and policy adjusted when needed.