Burkholderia pseudomallei: abscess in an unusual site.

Melioidosis is an infection caused by Burkholderia pseudomallei. It is an important human pathogen in tropical area. The clinical manifestations are protean and multisystem involvement. We report an unusual case of melioidosis with abscess at root of mesentery in an elderly, non-insulin dependent diabetic Thai women. She presented with prolonged fever and chronic abdominal pain. The early clinical diagnosis was carcinomatous mass with peritonitis. Diagnosis of melioidosis arose from the surgical finding and pus culture. Treatment with surgical drainage and ceftazidime followed by co-trimoxazole plus doxycycline had a good clinical outcome.

Risk factors for penicillin-resistant Streptococcus pneumoniae acquisition in patients in Bangkok.

To identify risk factors for acquisition of penicillin-resistant Streptococcus pneumoniae (PRSP) in patients in Bangkok, using a case-control study, the study included patients with clinical specimens which grew S. pneumoniae during January to December 1997, treated at a teaching hospital in Bangkok. Penicillin susceptibility was determined by E-test and strains with MIC of > 0.1 microg/ml were considered resistant. Cases were the patients who had PRSP, and patients who had penicillin-susceptible S. pneumoniae (PSSP) were controls. The study variables included age 15 years or younger, immunocompromised status, ventilatory support, and antibiotic use or hospitalization within the previous 3 months. There were 73 cases and 51 controls. Their ages were 0 to 87 years, with median age of cases 4 and controls 49 years. Pneumonia was the most common type of infection, being 47% in cases and 45% in controls. Univariate analysis revealed significant association of PRSP acquisition with previous antibiotic use (p<0.0001), age < or = 15 years (p=0.001) and previous hospitalization (p=0.002). Logistic regression analysis in order to adjust for confounding effects showed that the only significant risk factor was previous antibiotic use (OR 18.4; 95% CI 6.2-54.6). The major risk factor for acquisition of PRSP in this study population is recent antibiotic use. Decreased antibiotic use would reduce risk of acquisition of PRSP.

Salmonella krefeld in Thailand: II. Molecular biology of drug resistance.

Human salmonellosis due to Salmonella krefeld is very rare. During 1976-1978, a large outbreak of S. krefeld gastroenteritis occurred in Thailand, mainly in children. The majority of strains were multiply drug resistant with high minimum inhibitory concentration (MIC). The MIC for these drugs were ampicillin (Ap) 256-4096 mg/l, chloramphenicol (Cm) 256-512 mg/l, kanamycin (Km) 512- greater than 4096 mg/l, streptomycin (Sm) greater than 1024 mg/l, sulfamethoxazole (Su) 4096- greater than 8192 mg/l, tetracycline (Tc) 64-128 mg/l and trimethoprim (Tp) 64-256 mg/l. Resistance to Su and Tp declined after the period of the epidemic. The resistance genes were found to be highly transferable at a rate of 10(-2) to 10(-4). All strains with more than five resistance markers had large molecular weight plasmids of 120-140 megadaltons. The restriction profile analysis of plasmids from isolates collected from various regions of the country showed similarity of DNA fragment pattern. These isolates were resistant to Ap, Cm, Km, Sm, Su and Tc.

Salmonella krefeld in Thailand: I. Epidemiology, infection and drug resistance.

Information from the National Salmonella Shigella Center (NSSC), Thailand indicated that the most frequently isolated Salmonella serotype from humans during 1974-1975 was Salmonella typhi (33.1%), during 1976-1982 was S. krefeld (26.6%) and during 1983-1987 was S. derby (12.6%). Antimicrobial susceptibility study of various Salmonella serotypes indicated that S. krefeld was the serotype with multiple drug resistance persisting for the longest period of time. Human salmonellosis due to S. krefeld is very rare. During 1976-1978, a large outbreak of S. krefeld gastroenteritis occurred in Thailand, mainly in children. The outbreak spread countrywide and is currently endemic. Gastrointestinal symptoms are severe in young infants. Systemic invasion with bacteremia, meningitis and pneumonitis were reported. The antimicrobial susceptibility pattern of isolates varied from sensitive to multiply drug resistant. The common antibiotic resistances were to ampicillin (75-92%), chloramphenicol (33-75%), kanamycin (67-90%) and sulfamethoxazole-trimethoprim (15-52%). Resistance to gentamicin and sulfamethoxazole-trimethoprim declined after the period of the epidemic. Antimicrobial resistance patterns of 150 S. krefeld strains isolated in Thailand during 1978-1987 showed multiple drug resistance with up to seven drugs. The most common patterns were ApCmKmSuTp and ApCmKmSmSuTc.

Haemophilus influenzae and Streptococcus pneumoniae in children with acute respiratory infection.

The incidence of Haemophilus influenzae and Streptococcus pneumoniae in children with acute respiratory infection (ARI) under 5 years was carried out by throat swab culture, blood culture, body fluid or tissue culture in 688 patients from a community, 744 patients from a teaching hospital in Bangkok, 766 normal children from the community and 303 children from a hospital well baby clinic. H. influenzae was found in the throats of 15-20% of patients and in the throats of 4-6% of normal children (p less than 0.001 for both hospital and community patients). Only 12/332 strains (3.6%) of H. influenzae were type b. The rest of H. influenzae were non type b. The most common biotype of H. influenzae non type b was biotype II. S. pneumoniae was found in hospital patients in highly significant numbers compared to the controls (12% vs 4%). No significant difference was observed in strains from the community patients.

Drug resistance of Haemophilus ducreyi.

Chancroid, the disease caused by H. ducreyi is one of the common sexually transmitted diseases (STD) in Thailand and other tropical countries. In Thailand, the diagnosis of chancroid is still based on clinical appearance which may be confused with other STD manifested by genital ulcers. In recent years the increasing resistance strains of H. ducreyi to these antimicrobial agents has been reported so that cultivation and antimicrobial susceptibility tests of this organism have become more important. This study showed that MBV is the best medium for isolation with a success rate of 48%. All strains tested from isolates of this study were resistant to ampicillin, due to production of beta-lactamase. Approximately 99% of the strains were resistant to tetracycline 92% of strains were resistant to sulfamethoxazole and 32% were resistant to trimethoprim. All isolates were susceptible to chloramphenicol, ceftriaxone, erythromycin and the fluorinated quinolones ciprofloxacin, norfloxacin, ofloxacin and pefloxacin. Beta-lactamase enzymes produced by 37 strains of H. ducreyi were determined for their isoelectric point (pI). All had pI of 5.4, indicative of plasmid-mediated beta-lactamase type TEM-1.

Aetiologic agents of septic sore throat in Thai children.

A bacteriological study of children with respiratory infections in Bangkok during January to November 1976 revealed that 37% of the patients had symptoms and sign of bacterial pharyngotonsillitis. Twenty-six per cent of these children harboured Streptococcus pyogenes in their throats. The numbers of streptococci other than group A and Staphylococcus aureus were increased in the children with respiratory infections. However, Staph. aureus was found as the sole organism in children with exudate more often than in the children with only URI. The possible role of Staph. aureus in bacterial pharyngitis should not be ignored. Penicillin remains a drug of choice for the treatment of streptococcal pharyngitis. If penicillin is contraindicated, erythromycin should be preferred over lincomycin as a second choice of drug in order to avoid treatment failure if lincomycin resistant streptococci are present.

Pseudomonas pseudomallei: II. Laboratory and experimental studies in animals.

The cultural, biochemical characteristics and antibiotic sensitivity of strains of Pseudomonas pseudomallei isolated from four cases of melioidosis admitted to Ramathibodi Hospital are described. The organisms were gram-negative bacilli often with bipolar staining. The colonies were wrinkled when incubated for long periods. The characteristic non-specific uptake of dye from media into the colonies and their musty or earthy odour rendered them easily distinguishable from other organisms. All strains were sensitive to chloramphenicol and all but one were sensitive to tetracycline. All strains were resistant to colimycin and gentamicin. The pathogenicity of the strain isolated from a fatal case of peritonitis was studied in guinea pigs. The findings showed that following a large inoculation intraperitoneally, the animal developed acute septicaemia and died shortly afterwards. Only a few micro-abscesses were found on the surface of the liver. Chronic infection of longer duration occurred when a small number of organisms were introduced through a cutaneous abrasion. The lesions included pneumonitis and multiple abscesses of various organs including subcutaneous tissue, liver, spleen and mediastinum.