Antimicrobial susceptibilities of strains of Neisseria gonorrhoeae in Bangkok, Thailand: 1994-1995.

BACKGROUND AND OBJECTIVES: Failure of uncomplicated gonococcal infections acquired in the Far East to respond to doses of ciprofloxacin and ofloxacin recommended by the Centers for Disease Control and Prevention have been identified in Australia, the United Kingdom, and the United States. In the Republic of the Philippines, 54.3% of strains exhibited decreased susceptibility to fluoroquinolones; 12% of strains were resistant to ciprofloxacin. This study was undertaken to compare the antimicrobial susceptibilities of gonococcal isolates in Bangkok, Thailand, with those in the Republic of the Philippines. GOAL: To determine the frequency and diversity of antimicrobial resistance, particularly to fluoroquinolones, in gonococcal strains in Bangkok, Thailand. STUDY DESIGN: Strains of Neisseria gonorrhoeae isolated from 101 patients with uncomplicated gonorrhea in Bangkok, Thailand, in July, 1994 (46 strains) and November, 1994 to July, 1995 (55 strains), were characterized by auxotype/serovar class, antimicrobial susceptibilities, and plasmid profile. Susceptibilities were determined to penicillin G, tetracycline, ceftriaxone, cefixime, cefoxitin, ciprofloxacin, ofloxacin, norfloxacin, erythromycin, kanamycin, and thiamphenicol. RESULTS: Of 101 strains, 89.1% (90/101) were resistant to penicillin or tetracycline. Plasmid-mediated resistance to penicillin or tetracycline was identified in 33.7% (34/101) of the isolates: penicillinase-producing Neisseria gonorrhoeae (17.8%; 18/101), tetracycline-resistant Neisseria gonorrhoeae (7.9%; 8/101), and penicillinase-producing/tetracycline-resistant Neisseria gonorrhoeae (7.9%; 8/101). Most penicillinase-producing strains (96.2%; 25/26) possessed the 4.4-megadalton (Md) beta-lactamase plasmid; one strain possessed the 3.2-Md beta-lactamase plasmid. Chromosomally mediated resistance to penicillin and tetracycline was exhibited by 51.5% (52/101) of strains, and 4.0% (4/101) were tetracycline resistant. All strains were susceptible to spectinomycin. Of 21.8% (22/101) strains exhibiting decreased susceptibility to ciprofloxacin (minimal inhibitory concentration [MIC] > or = 0.125 microgram/ml), one strain (ciprofloxacin MIC, 0.5 microgram/ml; ciprofloxacin inhibition zone diameter of 23 mm) had MICs of 2.0 and 8.0 micrograms/ml for ofloxacin and norfloxacin, respectively, indicating resistance to these agents. Decreased susceptibility to ciprofloxacin was identified in strains with chromosomally mediated resistance to penicillin or tetracycline and in penicillinase-producing strains. CONCLUSIONS: In Bangkok, Thailand, gonococcal isolates exhibit resistance to penicillin, tetracycline, kanamycin, and thiamphenicol. Decreased susceptibility to fluoroquinolones is emerging in a variety of strains of N. gonorrhoeae. Thus, all gonococcal infections should be treated with antimicrobial therapies known to be active against all gonococcal strains to reduce the spread of strains exhibiting decreased susceptibilities to fluoroquinolones.

PIP: To assess the frequency and diversity of antimicrobial resistant strains of Neisseria gonorrhoeae in Thailand, endocervical or urethral strains were isolated from 101 patients at a Bangkok sexually transmitted disease clinic. Of the 101 strains, 90 (89.1%) were resistant to penicillin or tetracycline. Plasmid-mediated resistance to penicillin or tetracycline was found in 33.7% of isolates; this included penicillinase-producing N gonorrhoeae (17.8%), tetracycline-resistant N gonorrhoeae (7.9%), and penicillinase-producing/tetracycline-resistant N gonorrhoeae (7.9%). Moreover, 51.5% of all strains exhibited chromosomally mediated resistance to penicillin and tetracycline. All strains were susceptible to spectinomycin. 22 strains (21.8%) showed decreased susceptibility to ciprofloxacin, while another fifth demonstrated resistance to both fluoroquinolones and norfloxacin. Finally, more than 75% of strains exhibited decreased susceptibility to kanamycin and thiamphenicol. The penicillin/tetracycline resistance phenotypes identified in Bangkok were more similar to those of isolates in the US than in the Philippines, where decreased susceptibility to fluoroquinolones predominates. Given evidence of antimicrobial resistance to penicillin, tetracycline, kanamycin, thiamphenicol, and fluoroquinolones in Thailand, the choice of agents for the treatment of uncomplicated gonococcal infection should be considered carefully and periodic surveillance of antimicrobial resistance is recommended to permit timely revision of treatment protocols.

Saliva-based HIV-antibody testing in Thailand.

OBJECTIVE: To determine whether saliva could serve as an alternative to serum for HIV-antibody testing in an ongoing sentinel surveillance program in Thailand. METHODS: Serum and saliva specimens were collected from 1955 individuals in four of the 73 sentinel sites of the national surveillance program in Thailand. Intravenous drug users, female prostitutes, and men attending sexually transmitted disease clinics were included as participants. All specimens were collected and tested anonymously. Saliva was gathered with the Omni-Sal collection device and analyzed for the presence of HIV antibodies using the immunoglobulin G antibody-capture enzyme-linked immunosorbent assay (GACELISA) laboratory test, specially designed for low concentration body fluids. Our gold standard was serum, collected and analyzed independently from the saliva specimens, using an ELISA test for screening and Western blot for confirmation. Linkage between serum and saliva was blind to the laboratory. A set of HIV-positive and HIV-negative quality assurance samples for both serum and saliva were also analyzed blind. RESULTS: Findings are presented as observed in the field, and as quality assurance samples after the correction of various field and laboratory errors. The sensitivity of the GACELISA with saliva was 98.0% in the field (298 HIV-positive specimens), 100% after correction of errors (300 HIV-positive specimens), and 100% among the quality assurance samples (95 HIV-positive specimens). The specificity of the GACELISA was 99.4% in the field (1653 HIV-negative specimens), 99.6% after correction of errors (1654 HIV-negative specimens), and 100% among the quality assurance samples (96 HIV-negative specimens). CONCLUSION: Our findings support other published studies that also featured the GACELISA. We conclude that saliva is comparable to serum for assessing HIV antibodies in individuals for surveillance and screening purposes.

Treatment of acute gonococcal infections in Bangkok with a dose range of the new cephalosporin, cefodizime.

In this randomized dose range study conducted in Bangkok, 326 patients with presumed acute uncomplicated gonorrhoea were treated with a single intramuscular dose of either 0.25 g, 0.5 g, or 1.0 g of a new aminothiazole cephalosporin, cefodizime. One hundred and eighty men and 110 women were evaluable for efficacy. Pathogens were eliminated in all but 4 of these patients resulting in a cure rate of 99%, irrespective of dose, sex, or multiplicity of infected sites. A high percentage of the 290 strains of Neisseria gonorrhoeae isolated from the evaluable patients showed resistance to penicillin, and 40% were penicillinase producing (PPNG). The minimum inhibitory concentration of cefodizime for 90% of the PPNG strains was less than 0.04 mg/l. No clinically relevant adverse drug reactions were reported. This study demonstrates that a single 0.25 g dose of cefodizime is effective against both PPNG and non-PPNG strains in a geographic region characterized by high endemic antibiotic resistance.

Clinical and microbiological efficacy of a single dose of norfloxacin in the treatment of chancroid.

Forty-one men with a clinically and bacteriologically verified diagnosis of chancroid were given a single dose of 800 mg of norfloxacin and were examined clinically and bacteriologically four, seven and 14 days after treatment. Five patients were excluded from evaluation of efficacy due to concomitant infections or incomplete follow-up. Of the remaining 36 patients, 34 were cured and culture negative at follow-up controls. Another 15 men with culture-negative ulcers treated with 800 mg of norfloxacin as a single dose, were all cured clinically. The high cure rate and the good tolerability make norfloxacin a convenient and cheap alternative to intramuscular single dose therapy of chancroid.

Efficacy and safety of a single dose therapy of a 500 mg ciprofloxacin tablet in chancroid patients.

A single dose therapy of 500 mg ciprofloxacin was sufficient to cure 15 of 18 chancroid patients within six days and the remaining three within 7, 11 and 20 days respectively. The drug was well tolerated, and no serious side effects were observed. The MICs of ciprofloxacin for the isolated Haemophilus ducreyi strains ranged from 0.0015 to 0.02 mg/l (mean 0.01 mg/l). It may therefore be concluded from our study that the oral administration of ciprofloxacin to chancroid patients with or without buboes is highly effective and free from side effects.

AIDS and prevalence of antibody to human immunodeficiency virus (HIV) in high risk groups in Thailand.

Since September 1984, six cases of acquired immune deficiency syndrome (AIDS) and 11 cases of AIDS related complex (ARC) have been reported in Thailand. All people with AIDS were homosexual or bisexual men; two were Thai and the rest were European or American. Nine of the 11 people with ARC were homosexual or bisexual men, one was the female sexual partner of a man with AIDS, and one was a Thai man who had lived in the United States of America for several years, but denied having had any homosexual contact. Nine of the 11 people with ARC were Thai. In a survey in April 1985 at a resort area near Bangkok, antibodies to human immunodeficiency virus (HIV) (confirmed by western blot) were detected in 2.4% of 127 homosexual men and none of 77 female prostitutes. In a more extensive survey in October 1985, antibodies were detected in 0.8% of 720 homosexual men, but none of 2880 female prostitutes or 309 sexually active heterosexual men. HIV has been introduced into Thailand primarily by homosexual transmission. The public health policy of Thailand concerning AIDS is discussed.

PIP: Since September 1984, there have been 6 cases of acquired immunodeficiency syndrome (AIDS) diagnosed in Thailand, all of which involved homosexual or bisexual males. 2 of the AIDS patients were Americans, 2 were Europeans, and 2 were Thais. In addition, there have been 11 cases of AIDS-related complex (ARC), 9 involving homosexual or bisexual men. To gain more information on the prevalence of antibodies to human immunodeficiency virus (HIV) in high-risk groups in THailand, serum samples were collected in April 1985 from 127 asymptomatic Thai homosexuals and 77 female prostitutes from a beach resort near Bangkok. At this point, only 3 (2%) of the homosexual men and none of the prostitutes were HIV-positive. A 2nd, more extensive survey involving 3909 homosexual male prostitutes, female prostitutes, and heterosexual men from both the same beach resort and Bangkok was conducted in October 1985-January 1986. In this survey, homosexual male prostitutes in the beach resort were the only group with Western-blot-confirmed HIV- positive serostatus; 6 (2.5%) of the 244 members of this risk group screened were HIV-positive. Sexual contact with US or European homosexual men appears to be the major risk factor for HIV infection among Thais. To screen homosexual men for HIV, the Government of Thailand has set up a special sexually transmitted disease clinic in Bangkok and implemented HIV testing in government hospitals. Since May 1985, AIDS had been a disease notifiable to the Ministry of Health. The Ministry of Health has proposed that all patients with AIDS should be quarantined.

Efficacy of ofloxacin in uncomplicated gonorrhoea.

A randomised double blind trial comparing single oral dose therapy with 200 mg and 400 mg of ofloxacin, respectively was conducted at the Bangrak Hospital, Bangkok during the period December 6, 1985 to January 24, 1986. We treated 234 male patients diagnosed as having uncomplicated gonococcal urethritis with ofloxacin. Ofloxacin, at a single dose of 200 mg or 400 mg, was given to each of them. Fourteen patients were excluded for efficacy assessment. There were 223 patients left for safety assessment. The cure rates were 100% in both groups. Among 233 isolates tested, 48.5% were penicillinase producing Neisseria gonorrhoeae. The range of minimum inhibitory concentrations of ofloxacin was 0.008 to 0.063 mg/l. No adverse drug experiences were reported.

Rapid identification of penicillinase-producing Neisseria gonorrhoeae by detection of beta-lactamase in urethral exudates.

The production of fluorescent end-products with ampicillin as substrate can be used to detect beta-lactamase activity in biological fluids. A fluorescent spot test was evaluated as a rapid method of detecting beta-lactamase in the urethral exudates of men infected with Neisseria gonorrhoeae in Thailand. Among 208 men with culture-proven gonococcal urethritis, the fluorescent spot test was positive in 92 of 101 men from whom penicillinase-producing N gonorrhoeae (PPNG) were isolated and in 4 of 107 men from whom non-PPNG were isolated. The fluorescent spot test is a rapid, inexpensive, and sensitive method to detect PPNG and may be valuable in determining appropriate treatment for patients with gonococcal urethritis.

Randomised comparative study of ceftriaxone and spectinomycin in gonorrhoea.

From 26 April to 30 June 1983 a total of 200 men with uncomplicated gonococcal urethritis were randomly treated with either 2 g spectinomycin or 250 mg ceftriaxone, both administered intramuscularly. Of 197 isolates tested for the presence of the enzyme beta lactamase, 91 (46.2%) were positive (PPNG) and 106 (53.8%) were non-PPNG strains. All 93 patients treated with spectinomycin and followed up and 97 treated with ceftriaxone and followed up were cured. Ceftriaxone 250 mg administered by intramuscular injection is highly effective in treating gonococcal infections caused by both PPNG and non-PPNG strains and is an appropriate alternative to spectinomycin.