The present study describes the first internationally reported gonococcal AMR data in nearly four decades and the first molecular characterization of N. gonorrhoeae isolates in Poland. Despite the global concern of multidrug-resistant and possibly future untreatable gonorrhoea , the last published AMR data, with exception of β-lactamase production [36, 37], for gonococcal isolates from Poland are from the mid-to late-1970s and only published in Polish [34, 35, 38]. Furthermore, the susceptibility to internationally frequently used antimicrobials such as ceftriaxone, cefixime, spectinomycin, ciprofloxacin, and azithromycin has never been assessed. Overall, high prevalence of resistance, including multidrug resistance, was observed for internationally previously recommended antimicrobials such as ciprofloxacin (60.5%), tetracycline (43.0%), and penicillin G (22.4%), and the latter remains nationally recommended for treatment of gonorrhoea in Poland [32, 33]. Five per cent (range: 2.2%-21.4% during 2010-2012) of the gonococcal isolates in Poland were β-lactamase producing, which is substantially higher than the previously reported prevalence of 0.8% (range: 0-1.1%) during 2006-2009 . The prevalence of resistance to azithromycin was also relatively high (8.8%). Similar levels of resistance to ciprofloxacin, tetracycline, penicillin G and azithromycin have been described from many other countries in Europe and basically worldwide [3–6, 20–22, 45, 46], and none of these antimicrobials should be recommended for empiric first-line antimicrobial monotherapy in Poland or in many other countries globally. Accordingly, it is essential to promptly revise and strictly implement an up-to-date treatment guideline for gonorrhoea in Poland. The results of the present study provide a strong evidence base for this revision of the Polish treatment guidelines, which has been initiated. No isolates with resistance (MIC > 0.125 mg/L) to ceftriaxone or cefixime were found. However, worryingly the proportion of isolates displaying decreased susceptibility to ESCs (MIC = 0.125 mg/L), which have previously resulted in gonorrhoea ESC treatment failures [13, 15, 16, 44], rapidly increased from none in 2010, to 7.6% in 2011, and 13.9% in 2012. Ninety-three per cent of these isolates contained a mosaic penA allele, which has been associated with decreased susceptibility or resistance to ESCs in many countries [3, 5, 9–19, 24–30]. It is crucial to continuously follow the spread of gonococcal strains with multidrug resistance and decreased susceptibility or future resistance to ESCs in Poland. Accordingly, gonococcal AMR (ideally also treatment failures) will be surveyed annually in Poland (isolates are prospectively collected) and preparations for joining the European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) [46,47], which acts in the EU/EEA, have been initiated.
Using NG-MAST, the present study identified a diversified gonococcal population in Poland during 2010-2012, with 66 different NG-MAST STs among the 228 isolates. ST1407 (25.4% of all isolates) was the most frequent ST and also significantly increased from 2010 (0%) to 2012 (42.6%). Of the ST1407 isolates, 15.5% displayed decreased susceptibility to ceftriaxone and 41.4% to cefixime, and all contained a mosaic penA allele. NG-MAST ST1407 has been previously shown to account for most of the decreased susceptibility or resistance to ESCs in Europe and to be responsible for treatment failures with cefixime in Norway , Austria , France  and Canada , as well as with ceftriaxone in Slovenia . The high number of unique STs (n = 38) and novel STs (n = 34), which were identified in Poland, may be associated with suboptimal diagnostics (only random gonorrhoea patients and/or isolates are identified), contact tracing (sexual contacts having the identical ST are not traced) and epidemiological surveillance (sexual transmission chains spreading a single ST are not identified or followed-up), locally evolved STs (novel STs because no NG-MAST studies have been previously performed in the country) or STs imported from abroad. However, some main ST clusters caused by clonal spread of, e.g., ST1407 (n = 58), ST 2992 (n = 17), ST1405 (n = 12), and ST1861 (n = 10) were identified, which indicate some larger sexual transmission chains.
The reported incidences of gonorrhoea in Poland (<2 cases per 100,000 inhabitants annually during last decade) have been substantially lower than in neighbouring countries/regions, for example, in 2011 in Belarus (33.4), Kaliningrad Oblast (27.5), Ukraine (20.1), Lithuania (6.7), Czech Republic (6.7) and Slovakia (3.6) [2, 47]. The gonorrhoea incidence in Poland is likely underestimated, due to suboptimal diagnostics (more sensitive methods such as NAATs and/or culture need to be more frequently used), access to appropriate diagnostics and lack of screening of asymptomatic patients, and incomplete case reporting (particularly among private health care providers) as well as epidemiological surveillance.