TABLE 3.

Comparison of geometric mean MICs according to anatomic site of infection

Antimicrobial and MIC type	Geometric mean MIC (μg/ml)a			Ratio of geometric mean MICs (95% CI)
	Pharyngeal (n = 205)	Rectal (n = 261)	Urethral (n = 976)	Pharyngeal vs urethral	Rectal vs urethral	Rectal vs pharyngeal
Azithromycin
Geometric mean MIC	0.3129	0.3034	0.3035	1.03 (0.90–1.19)	1.00 (0.87–1.15)	0.97 (0.81–1.16)
City-adjusted geometric mean MIC	0.3369	0.3166	0.2954	1.14 (0.98–1.33)	1.07 (0.94–1.23)	0.94 (0.78–1.12)
Cefixime
Geometric mean MIC	0.0270	0.0325	0.0292	0.92 (0.82–1.04)	1.11 (0.98–1.26)	1.20 (1.03–1.40)b
City-adjusted geometric mean MIC	0.0275	0.0323	0.0287	0.96 (0.85–1.09)	1.13 (0.99–1.28)	1.17 (1.01–1.37)b
Ceftriaxone
Geometric mean MIC	0.0155	0.0161	0.0154	1.00 (0.88–1.14)	1.05 (0.93–1.18)	1.04 (0.89–1.22)
City-adjusted geometric mean MIC	0.0153	0.0157	0.0150	1.02 (0.90–1.17)	1.05 (0.93–1.19)	1.03 (0.88–1.20)
Ciprofloxacin
Geometric mean MIC	0.1241	0.1759	0.1160	1.07 (0.62–1.84)	1.52 (0.92–2.51)	1.41 (0.73–2.77)
City-adjusted geometric mean MIC	0.1053	0.1599	0.1132	0.93 (0.54–1.60)	1.41 (0.85–2.34)	1.52 (0.78–2.95)
Penicillin
Geometric mean MIC	0.6229	0.7080	0.7911	0.79 (0.67–0.93)b	0.90 (0.76–1.05)	1.14 (0.93–1.39)
City-adjusted geometric mean MIC	0.6660	0.7492	0.7813	0.85 (0.72–1.00)	0.96 (0.82–1.12)	1.13 (0.93–1.37)
Tetracycline
Geometric mean MIC	1.2974	1.5214	1.5367	0.84 (0.71–1.01)	0.99 (0.83–1.18)	1.17 (0.94–1.46)
City-adjusted geometric mean MIC	1.3684	1.5763	1.5187	0.90 (0.75–1.08)	1.04 (0.87–1.24)	1.15 (0.93–1.43)

^aGeometric mean MICs, ratios of geometric mean MICs, and 95% confidence intervals (CIs) were calculated by employing generalized linear models.

^bP < 0.05 (CI does not contain 1).