Analysis of the sex ratio of reported gonorrhoea incidence in Shenzhen, China

Xiong, Mingzhou; Lan, Lina; Feng, Tiejian; Zhao, Guanglu; Wang, Feng; Hong, Fuchang; Wu, Xiaobing; Zhang, Chunlai; Wen, Lizhang; Liu, Aizhong; Best, John McCulloch; Tang, Weiming

Timely and standardised treatment is needed to prevent the transmission of 'superbugs'. As Liu et al 21 found in Hefei city (the capital of Anhui province, China), 82% of patients with gonorrhoea could be identified by clinic laboratories, which was much higher than that in our research. Maybe the different study site and research design have led to the difference in results. Laboratory testing for NG is the key point to find new gonorrhoea cases, especially for asymptomatic infections. Cases reported to CISDCP should be detected positive for gonorrhoea. NG test should be conducted for asymptomatic patients. The current 'Diagnostic criteria for gonorrhea' of China, which were implemented from 15 October 2007 and recommended microscopy and culture to test NG, have a large impact on the appearance of gender difference. Compared to culture, microscopy is quick and the result can be obtained in minutes. On the other hand, culture methods usually require 2-7 days (depending on the hospital) to obtain results. 22 A large number of female patients are unwilling to take such a long time to get an NG test result. Therefore, when female patients present with mild symptoms or non-specific symptoms and seek medical service in a hospital, physicians may opt for empirical antibiotic treatment instead of an NG test. By then, many female patients lost the opportunity to be detected, which explains why female patients have a higher untested rate in our study. Besides that, Gram stain has a relatively low sensitivity (around 70% in China), while NG culture has a relative high sensitivity (80-95% in China). 23 However, culture methods have a high potential for human error. When collecting the sample, NG specimens are easily contaminated by other bacteria and die after separation from the host, 24 leading to many false negatives. These differences in laboratory and clinical diagnosis of gonorrhoea are likely to have contributed to the underestimation of male and female cases and an inflated male-to-female ratio. Moreover, the inadequate responsibility of the physician and ability of laboratory personnel also have a negative impact on the accuracy of gender difference of reported gonorrhoea incidence.