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.

Systemic nontyphoidal Salmonella infection in normal infants in Thailand.

BACKGROUND: The relative paucity of information about systemic nontyphoidal Salmonella (NTS) infection in infants without an underlying disease prompted this study. METHODS: Infants without an underlying disease, who had positive cultures for NTS from their normally sterile sites during 1978 through 1998, were included. Their medical records were reviewed. RESULTS: The study included 75 eligible infants; 68 (91%) had positive blood cultures. The spectrum of disease included transient bacteremia (5), bacteremia without localized infection (37), bone and joint infection (5) and meningitis (28); 53 and 88% of infants were < or =3 and < or =6 months old, respectively. All infants with localized infection were < or =7 months old, and infants with meningitis were 3.35+/-1.87 (mean +/- SD) months old. In bacteremic infants risks for localized infection and meningitis were 30 and 24%, respectively. Abnormal neurologic findings were the only predictor for meningitis. Relapse of meningitis occurred in two infants despite treatment with cefotaxime for 4 and 6 weeks. Severe neurologic deficit occurred in 21% of infants with meningitis. Of 11 infants with meningitis who received early treatment at this tertiary care center, 1 died but none had severe neurologic deficits; whereas of 17 referred cases, 2 died and 6 had severe neurologic abnormalities. No death occurred in infants without meningitis. CONCLUSION: Systemic NTS infection in normal infants has a variable disease spectrum. Infants 0 to 6 months of age are at high risk for localized infection, especially meningitis.

Antimicrobial resistance in Burkholderia pseudomallei.

Four strains of Burkholderia pseudomallei were used to determine the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill curves with 13 single antimicrobial agents: ceftazidime, piperacillin, imipenem, amoxicillin/clavulanic acid, doxycycline, cotrimoxazole, kanamycin, rifampicin, ciprofloxacin, trovafloxacin, clarithromycin, azithromycin and meropenem. The time-kill studies were also performed with 33 pairs of combinations of the above antimicrobial agents: 15 combinations which would be expected to be used for acute therapy and 18 combinations for maintenance therapy. The results show that the single and combination antimicrobial agents with bactericidal effects against the four strains of B. pseudomallei which should be used for clinical trials in acute melioidosis are: imipenem, meropenem, and imipenem + azithromycin. The combination antimicrobial agents which should be further studied for the ability to eliminate biofilm and intracellular killing effect are ciprofloxacin + clarithromycin, ciprofloxacin + azithromycin, and imipenem + azithromycin.

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.

Electron microscopy study of the mode of growth of Pseudomonas pseudomallei in vitro and in vivo.

The mode of growth of Pseudomonas pseudomallei in culture media and in the lung tissue of infected humans and animals was studied using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). In culture media, P. pseudomallei cells were seen to be entrapped in microcolonies within large amounts of intercellular fibrous material. The lung tissue of infected humans and animals showed that bacterial cells growing in lung tissue were surrounded by radially arranged fibres that constitute a very well defined glycocalyx structure. In the infected areas of the animal lung tissue, bacterial cell could be seen to have formed glycocalyx enclosed microcolonies that displaced host cell components, e.g. the nucleus of a phagocyte. The presence of bacteria in unusual locations indicated that effective phagocytosis was not occurring. The demonstration that cells of P. pseudomallei produce exopolysaccharide glycocalyces and form glycocalyx enclosed microcolonies in laboratory media and in lung tissue of infected humans and animals and the presence of bacteria in unusual locations contribute to a new understanding of the mechanism whereby this organism can cause persistent chronic infections.

Resistance of Pseudomonas pseudomallei growing as a biofilm on silastic discs to ceftazidime and co-trimoxazole.

We have examined the resistance of Pseudomonas pseudomallei biofilm cells to ceftazidime and cotrimoxazole. A large number of these biofilm cells remained viable at 12 and at 24 h, except in the biofilm treated with 200 times the MIC of ceftazidime. The inherent resistance of P. pseudomallei biofilms to conventional antibiotics may explain the lack of success in the treatment of the chronic manifestations of this bacterial infection.

An outbreak of Salmonella urbana infection in neonatal nurseries.

An outbreak of neonatal infection with Salmonella urbana in three neonatal wards of a teaching hospital in Bangkok, Thailand is described. The outbreak lasted for 5 days. Fifty-seven neonates had gastrointestinal infection, 37 had diarrhoea, and three had bacteraemia. The attack rates were 43% for infection, 29% for diarrhoea, and 2.3% for bacteraemia. Epidemiological evaluation suggested that a contaminated wash basin in the labour nursery was the source of infection. Delay in controlling this outbreak occurred because the staff assumed that person-to-person transmission was the mode of spread, thus ignoring epidemiological data that would have led to the identification of the source of infection.

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.

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.

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.

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.

Increasing resistance to trimethoprim-sulfamethoxazole among isolates of Escherichia coli in developing countries.

Resistance of Escherichia coli to trimethoprim (TMP)-sulfamethoxazole remains at 3%-8% at many medical centers within the United States. In this study a 44% resistance rate was observed among E. coli isolated at a pediatric hospital in Santiago, Chile, and a 40% resistance rate at a general teaching hospital in Bangkok, Thailand. Most isolates were from urinary tract infections and showed high-level resistance (minimal inhibitory concentration of TMP greater than 1,000 micrograms/ml). Nineteen of 35 isolates tested transferred resistance to TMP; most cotransferred resistance to streptomycin and sulfonamides. Dihydrofolate reductase type I was detected by gene probing in 14 of 35 strains. Subsequent investigations in Brazil, Honduras, and Costa Rica revealed that this high rate of resistance was not an isolated phenomenon.

Epididymo-orchitis due to Pseudomonas pseudomallei.

We report the first case of epididymo-orchitis caused by Pseudomonas pseudomallei. The diagnosis was made by isolation of the organism from testicle pus and urine. Treatment was successful with chloramphenicol and co-trimoxazole.

Penicillin concentrations in cerebrospinal fluid after different treatment regimens for syphilis.

The concentrations of penicillin in the cerebrospinal fluid (CSF) were compared simultaneously with those in the serum in 17 patients with syphilis. The antibiotic concentrations were measured by the agar well diffusion method. There were no detectable concentrations of penicillin in the CSF after administration of benzathine penicillin 2.4 megaunits, benzathine penicillin 7.2 megaunits, procaine penicillin in aluminium monostearate (PAM) 12 megaunits, or aqueous procaine penicillin G 2.4 megaunits. Only after high doses of aqueous penicillin G 24 megaunits daily or aqueous penicillin G 2 megaunits daily together with oral probenecid 2 g daily was penicillin detectable in the CSF. The concentrations after the latter regimen were the highest and much higher than the minimum inhibitory concentration for Treponema pallidum.

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.