Second-line drug susceptibilities of multidrug-resistant tuberculosis strains isolated in Thailand: an update.

The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) and the emergence of extensively drug-resistant tuberculosis (XDR-TB) globally hamper the successful treatment and effective control of TB. Information on second-line drug susceptibility, which is of utmost importance for patient care, is still limited. This study demonstrates the susceptibilities of 1447 strains of MDR-TB, including 58 XDR-TB strains, isolated from Siriraj Hospital, Bangkok, Thailand, to aminoglycosides, fluoroquinolones, ethionamide (ETH), para-aminosalicylic acid (PAS) and linezolid. Results revealed that 93-94% of the MDR-TB strains were susceptible to aminoglycosides, 85-98% to fluoroquinolones, 78% to ETH, 85% to PAS and 99% to linezolid.

Development and evaluation of a one-tube seminested PCR assay for the detection and identification of Penicillium marneffei.

A one-tube seminested polymerase chain reaction (PCR) assay was developed to detect and identify Penicillium marneffei DNA coding for 18S rRNA both from purified DNA and from clinical samples. DNA from 120 strains of organisms and 19 blood samples from AIDS patients was amplified with F3, CPL1 and PM primers. Under optimized conditions, these primers detected 100% specifically amplified products of 251 and 331 bp from all P. marneffei DNA preparations (47 strains) and from two blood samples of AIDS patients suspected to suffer from penicilliosis marneffei. The assay was sensitive to detect as little as 10 pg purified DNA, which is equivalent to 250 cells. This PCR assay might be useful as an alternative test, if a rapid diagnosis of penicilliosis marneffei is needed.

An open, non comparative study of ofloxacin i.v. on the treatment of acute symptomatic urinary tract infection.

The clinical efficacy and the safety of ofloxacin i.v. in 35 acute symptomatic urinary tract patients were evaluated. The drug was intravenously administered, 400 mg starting dose then 200 mg once-daily for 3-5 days. The therapeutic success rate and eradication rate in UTI case were 100 per cent in all cases when evaluated immediately after completion of drug treatment, therapeutic success rate and eradication rate at the follow-up evaluation were 97.2 per cent and 91.6 per cent respectively. Also, 5 cases of acute bronchitis and 2 salmonellosis were also administered intravenously, 400 mg once-daily dose and 400 mg twice daily dose respectively. No serious side effects of ofloxacin i.v. therapy were observed in any of our patients.

Antifungal drug combinations for Cryptococcus neoformans and Prototheca spp.

Seventy-one isolates of Cryptococcus neoformans and 5 isolates of Prototheca spp. were tested for in vitro susceptibility against amphotericin B alone and against the combination of amphotericin B with each clinically relevant concentration of flucytosine (5-FC) and rifampin by broth dilution methods. The combinations of amphotericin B and rifampin produced greater effect on reduction of the minimal inhibition concentration (MIC) of amphotericin B than did either drug used individually. Flucytosine combined with amphotericin B produced little or no reduction of the MIC compared with amphotericin B alone.

In vitro activity and clinical evaluation of cefixime in urinary tract infection.

Thirty-five women with uncomplicated acute lower urinary tract infections proven by significant pre-treatment bacteriuria (> or = 10(5)CFU/ml) were treated with an oral dose of 100 mg cefixime twice a day for seven days. Thirty five patients included in this study were checked for response to treatment on the last day of therapy, 7-14 days and 4 weeks post therapy. The clinical response and bacterial eradication rate for cefixime were 91.4 per cent (32/35). The infecting organisms, E. coli and Proteus mirabilis, were inhibited at MIC90 = 0.5 and < or = 0.03 microgram/ml, and MBC = 1 and 0.06 microgram/ml respectively. No adverse events were found in this study.

Cefaclor therapy in uncomplicated cystitis.

Thirty patients with acute urinary tract infection were treated orally with 500 mg of cefaclor three times a day for 7 days. Urine cultures were made before treatment and after therapy. In 97 per cent (29/30) of these patients clinical success was achieved and in 90 per cent (27/30) of them, pathogens were eradicated. Our study showed that cefaclor was still active against most Enterobacteriaceae, such as Escherichia coli and Klebsiella species, the principle pathogens of urinary tract infection. No adverse effects of cefaclor were observed in this study.

Immunobiological diagnosis of tropical ocular diseases: Toxocara, Pythium insidiosum, Pseudomonas (Burkholderia) pseudomallei, Mycobacterium chelonei and Toxoplasma gondii.

Of the sera obtained from 18 patients with ocular diseases comprising ocular larva migrans (OLM), Toxoplasma gondii, Mycobacterium chelonei, Pythium insidiosum bacteria and tumour, 3 sera were positive for Toxocara antibody at the titre over 1/1600 ELISA. All 3 of these sera came from males with unilateral grayish fundi. We demonstrated the value of the direct immunofluorescent assay (DIFA) on vitreous specimens from 7 cases of Toxoplasma retinitis. One vitreous specimen under electronmicroscopic examination revealed bradyzoites of T. gondii. In addition, a few cases of keratoconjunctivitis/ corneal ulcer with endophthalmitis, due to P. insidiosum, Ps. pseudomallei and Mycobacterium chelonei, were also diagnosed.

Comparison of polymerase chain reaction and conventional culture for the detection of legionellas in hospital water samples.

A detection system for Legionella spp. based on the polymerase chain reaction (PCR) was used to assess the diagnostic value of PCR for the surveillance of contamination of man-made water systems by legionellas. A previously-published primer system was chosen to amplify a fragment of the 5S-ribosomal gene of Legionella spp. A total of 78 water samples from various sources were examined by PCR and culture on MWY Legionella selective agar. Fifty-seven of 78 water samples were positive by both test systems (73%), nine were positive by PCR only (11.5%), another nine were positive by culture but negative by PCR (11.5%), and three were negative by both techniques (3.8%). The PCR was inhibited when large amounts of rust were present in the samples. Culture failed to detect legionellas in samples that contained large numbers of other bacteria capable of overgrowing the legionellas. These results show that PCR is a rapid and sensitive technique for the detection of legionella contamination in water samples and that PCR and culture complement each other in monitoring of environmental water samples.

Immunodiffusion test for diagnosing basidiobolomycosis.

An immunodiffusion test was developed for the diagnosis of basidiobolomycosis. When culture filtrate antigen (CFA) from Basidiobolus ranarum was reacted against two human patient and two rabbit antisera, 2 precipitin bands, inner (N) and outer (Y), were revealed for both patient and rabbit antisera. A line of identity was also observed between precipitin bands obtained with patient and rabbit sera. When CFA from B. ranarum (B CFA) was reacted against rabbit sera which contained antibody to Conidiobolus coronatus and Pythium insidiosum, 1 precipitin band corresponding to inner band (N) was observed. This finding showed that B. ranarum, C. coronatus and P. insidiosum shared at least one common antigen. After B CFA was absorbed with Pythium rabbit antiserum, the inner precipitin line that occurred between B CFA and rabbit antisera of Pythium and Conidiobolus disappeared. However, with Basidiobolus rabbit antiserum, the result did not change. The antigens which could be demonstrated by inner (N) and outer (Y) precipitin bands were heat stable at 56 degrees C for 30 min. The titer of the antibodies specific to these antigens decreased as the lesions subsided. When B. ranarum CFA was reacted against sera from 20 apparently normal persons, 20 diabetes mellitus patients, 5 aspergillosis patients, 2 candidosis patients and 3 pythiosis patients, no precipitin band was found. B. ranarum CFA was also treated with each rabbit antiserum specific to Candida albicans, Malassezia furfur and Aspergillus fumigatus. No precipitin bands occurred with any of these antisera. Thus, this test was found to be practical, sensitive and specific, and can be used to monitor patients infected with Basidiobolus ranarum.

Diagnosis of systemic candidosis by immunodiffusion test with locally prepared antigen.

Locally-made C. albicans, C. tropicalis, C. krusei antigens and antisera were made and compared with reference C. albicans and C. krusei antigens and antisera from the Center for Disease Control (CDC), Atlanta, Georgia, U.S.A., and the Provincial Laboratory of Public Health, University of Alberta, Edmonton, Alberta, Canada, respectively. The local antigens and antisera showed 3 precipitin bands when reacted with locally-made and reference antisera. When tested with human sera from 171 normal persons (aged 17-24 years), 30 Candida vaginitis, 30 Candida balanitis, 30 mucocutaneous candidosis, 30 pityriasis versicolor and 10 aspergillosis patients revealed no precipitin band. When tested with cryptococcosis, 2 out of 6 sera showed a precipitin band but only at 1:1 dilution. Four candidosis sera offered by CDC showed precipitin bands at dilutions up to 1:4. Three Thai candidosis sera also showed precipitin bands at dilutions up to 1:2. Therefore, we judged the baseline titer for Thai population to be 1:2.

Immunodiffusion test for diagnosing human pythiosis.

An immunodiffusion test was developed for diagnosing subcutaneous and systemic pythiosis in humans. When culture filtrate antigen (CFA) from P. insidiosum was reacted against patient and rabbit antisera, 1-5 precipitin bands occurred both in patient and rabbit antisera, and a line of identity also occurred between patient and rabbit sera. When control P. insidiosum CFA was reacted with 30 apparently normal persons, 20 Thalassemia patients, 2 candidosis and 5 aspergillosis patients, no precipitin bands were found. P. insidiosum CFA also tested with rabbit antibodies to B. dermatitidis, C. immitis, H. capsulatum, P. brasiliensis, C. albicans, M. furfur and A. fumigatus revealed no cross reactions. This test is practical, sensitive and specific.

A study of pityriasis versicolor in Bangkok (Thailand)

A total of 410 cases of pityriasis versicolor were studied in the Division of Dermatology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, during January to December 1987. These comprised 1% of all skin disorders, while infection caused by fungus comprised 17%. Most persons infected with pityriasis versicolor were 12-21 years old (mean age 20 years) and 47% were male and 53% were female. The common sites of infection were back, arms, face and trunk. The colors of lesions found were white (83%), brown (7%), pink (6%) and ashy (4%). Both forms of M. furfur were isolated, the ovale form in 97% and the orbiculare form in 3% of cases. The colors of the lesions did not depend on the form of the organism. Mycological and immunological studies confirmed that the two forms were different stages in the complex developmental cycle of a single species.

In vitro and clinical evaluation of ofloxacin in urinary tract infection and enteric fever.

During 1984 to 1988, 35 patients with urinary tract infection (UTI) and 37 patients with enteric fever were treated successfully with 400 mg ofloxacin twice a day for 7 to 10 days. Clinical cure or improvement was observed in 31 of the 35 patients with UTI; 32 patients were bacteriologically assessed and eradication was achieved in all of them. Ofloxacin was particularly effective in the treatment of enteric fever in 35 patients; eradication was achieved in all of them; 34 patients were clinically cured within 4 days, however, one patient with bacteraemia due to Salmonella paratyphi A subsequently died, due to his underlying disorder. The MIC90 of the Enterobacteriaceae including Salmonella was less than 0.12 micrograms/ml. Interestingly, beta-lactamase-producing strains of Salmonella and other Enterobacteriaceae in the present study were 28% and 29%, respectively. Ofloxacin therefore offers an effective b.i.d. dosage schedule for enteric fever and UTI due to beta-lactamase-producing bacteria.