Table 2. Quality assessment of the studies included in meta-analysis.

Study number	First author, year	Locationa	Isolates collection periodb	Populationc	Isolates identificationd	NO. isolatese	NO. of NG isolates≥100f	Control strainsg
1	Fekete T, 1991	+	−	+	+	+	−	−
2	Kohl PK, 1995	+	+	−	+	+	+	−
3	Lewis DA, 1995	+	−	−	+	+	+	+
4	Tapsall JW, 1995	+	+	−	−	+	+	−
5	Lewis DA, 1996	+	+	−	+	+	+	+
6	Nissinen A, 1997	+	+	+	+	+	+	−
7	Fox KK, 1997	+	+	−	−	+	+	+
8	Komeda H, 2004	+	+	+	−	+	+	−
9	Shigemura K, 2004	+	+	+	−	+	−	+
10	Kagami Y, 2005	+	+	+	−	+	+	−
11	Donegan EA, 2006	+	+	+	+	+	+	+
12	Zarakolu P, 2006	+	−	+	+	+	−	+
13	De Jongh, 2007	+	+	+	+	+	+	+
14	Wang S, 2007	+	+	+	−	+	+	+
15	Palmer HM, 2008	+	+	−	−	+	+	−
16	Apalata T, 2009	+	+	−	+	+	−	+
17	Tanaka M, 2011	+	+	+	+	+	+	+
18	Martin I, 2011	+	+	−	−	+	+	+
19	Lee H, 2011	+	+	+	−	+	+	+
20	Endo K, 2011	+	+	+	+	+	+	+
21	Tanaka M, 2011	+	+	−	−	+	+	−
22	Allen VG, 2011	+	+	−	+	+	+	+
23	Carannante A, 2012	+	+	+	−	+	+	+
24	Takahashi S, 2012	+	−	+	+	+	−	+
25	Mehta S, 2012	+	+	+	+	+	+	−

^a“+” means the study specifying the location where NG isolates were collected; “−” stands for this information missing from the study.

^b“+” means the study specifying isolates collection period; “−” stands for this information missing from the study.

^c“+” means the study describing the population from whom NG isolates were obtained; “−” stands for this information missing from the study.

^d“+” means the study describing the method of identifying NG isolates; “−” stands for this information missing from the study.

^e“+” means the study indicating the number of tested NG isolates; “−” stands for this information missing from the study.

^f“+” means the study including at least 100 tested NG isolates; “−” stands for the study failing to do it.

^g“+” means the study utilizing control strains recommended by WHO in determining MICs with agar dilution method; “−” stands for the study failing to do it.