was 38.9%. It was slightly lower than that in 1979 (45.6%) and in 1984/85 (48.5%).
In provinces, municipalities and regions: The proportions of re-treated bacteriological positive patients in provinces, municipalities and regions were 21.2-48.2% (mean 34.8%); the proportions of re-treated somear positive patients were 21.2-58.6% (mean 38.9%). Xizhuang, Neimeng, Hainan and Sichuan had lower proportion of re-treated bacteriological positive and smear positive patients; the former were 21.2%, 21.6%, 23.9% and 20.0% respectively; the later were 21.2%, 21.4%, 25.0% and 26.6% respectively. Heilogjiang, Qinghai, Zhejiang and Liaonig had higher proportion of re-treated bacteriological positive and smear positive patients; the former were 48.2%, 47.1%, 46.8% and 43.2% respectively; the later were 58.6%, 50.0%, 56.5% and 50.8% respectively.
Age group: In this survey, 0-14 age group had the lowest proportion (3.3%) of re-treated smear positive patients and the age group above 60 years old followed (29.5%). 30-44 age group had the highest proportion (51.2%) of re-treated smear positive patients. The above character was basically similar in three surveys; but the proportion of re-treated smear positive patients in all age groups except age group above 60 years of age in this survey were lower than that of 1979 and 1984/85 survey.
In city and countryside: The proportions of re-treated smear positive patients in city, town and countryside in 1984/85 survey were 57.8%, 68.4% and 46.4% respectively; they were 46.7%, 43.0% and 38.2% respectively in 1990 survey. In these five years, the proportions in city, town and countryside showed a 11.1%, 25.4% and 8.2% decrease respectively. In 1984/85 survey, the proportion of re-treated smear positive patients in countryside was 11.4% lower than that of city; it was 8.5% in 1990 survey.
(3) Proportion of Re-treated Smear Positive Patients
In whole country: In this survey, the proportion (75.9%) of re-treated smear positive patients was lower that in 1979 (82.2%) and in 1984/85 (86.4%).
In provinces, municipalities and regions: Zixhuang, Beijing, Hainan and Fujian had lower proportion of re-treated known smear positive patients; they were 46.7%, 50.0%, 57.6% and 57.9% respectively. Shanghai, Zhejiang, Guangdong and Guizhou had higher proportion of re-treated known smear positive patients; they were 100.0%, 96/3%, 94.4% and 92.3% respectively. In comparison with the results in 1979, Beijing, Neimeng and Ningxia showed a significant decrease of the proportion of re-treated cases; The percentages of decrese were 41.3%, 38.2% and 37.5% respectively. Guizhou, Xingjiang and Hebei showed a significant increase; the percentages of increase were 29.8%, 24.0% and 18.5% respectively.
Although the proportions of re-treated smear positive patients in this survey in the country and some provinces, municipalities and regions were lower than in the past two surveys, but it still amounted to 3/4 of total smear positive patients in the country. The fact indicated that majority of the detected infectious sources became re-treated patients owing to the poor effect of initial chemotherapy.
? EXAMINATION OF DRUG RESISTANCE AMONG PULMONARY TUBERCULOSIS PATIENTS
The examination of drug resistance among pulmonary tuberculosis patients were carried out in 25 provinces, municipalities and regions in this survey; there were only 8 provinces and municipalities who carried out drug resistance test in 1979 and it increased to 14 in 1984/85. Six anti-tuberculosis drugs i.e. streptomycin (SM), isoniazid (INH), Paraamino salicylic acid (PAS), Rifampicin (RFP), ethambutol (EMB) and thioacetazone (TB1) were selected for drug resistance test.
In accordance with the history of chemotherapy on tuberculosis patient, initial drug resistance or secondary drug resistance were defined. Initial resistance: the patient has never been treated with any anti-tuberculosis drugs in the past before examination (the patient denied having history of chemotherapy). Secondary resistance: the patient had received anti-tuberculosis chemotherapy in the past and drug resistance was detected in this survey.
1. Number of Patients Examined for Drug Resistance test
A total of 1,595 cases who had a positive culture results for tubercle bacilli were examined for drug resistance testing in 25 provinces, municipalities and regions. 48.9% of examined patients had been treated with ant-tuberculosis drugs and 51.1% had never been treated before.
2. Rate of Drug Resistance
The criteria for drug resistance is that 20 or more colonies were grown on the culture media containing anti-tuberculosis drugs and the number of colonies is similar to that in control tubes.
In whole country: Drug resistance was encountered in 637 cases among 1,595 pulmonary tuberculosis patients. The drug resistance rate was 39.9%.
The rates of initial and secondary drug resistance were 28.1% and 41.1% respectively.
In city and countryside: The initial drug resistance rate in city (30.0%) and countryside (31.5%) was close to the average rate of the country (31.7%); the rate in town was slightly higher than the former two. Regarding the secondary drug resistance, city had the highest rate (56.1%); the rates in town and countryside were 51.2% and 47.1% respectively.
In comparison with the results in 1984/85: The criteria of drug resistance in 1984/85 survey was based on 10 colonies. Based on this criteria, the rates of drug resistance in 1984/85 and 1990 were 56.1% (516/919) and 46.4% (740/1,595) respectively; the rates of initial resistance were 47.8% (213/446) and 37.4% (291/779) respectively.
