A child with a traumatic uriniferous perirenal pseudocyst was presented. The diagnosis was not made by routine radiological studies, but ultrasound examination demonstrated a perirenal fluid accumulation clearly. The usefulness of the ultrasound examination in the diagnosis of this condition was emphasized. The characteristic finding in ultrasonogram consists of a hydronephrotic kidney and its invagination into the echolucent mass. When perirenal cystic lesions are demonstrated by ultrasound, the junctional zone between the cyst and kidney should be carefully checked for signs of invagination of the kidney into the cyst.

Over a 14 year period, there were 20 patients who presented with staphylococcal empyema from whom methicillin‐resistant Staphylococcus aureus (MRSA) was isolated. Twelve cases were community‐acquired and 8 were hospital‐acquired infections. Patients were treated with penicillinase‐resistant penicillin, cephalosporin or carbapenem in combination with or without aminoglycoside. They were also treated with drainage or thoracentesis. However, they were refractory to treatment and 7 patients, 6 of whom were suffering from bacteremia, died. One bacteremic patient was treated with vancomycin and was cured. In an area of endemic MRSA, vancomycin may be the first choice in the initial treatment of staphylococcal empyema until antimicrobial susceptibility can be determined.

Quantitative fecal bacteriology was performed in eight immunocompromised children with septicemia. The most marked change observed was suppression of the anaerobic bacteria. In seven patients, the predominant organisms were aerobic gram‐negative bacilli (GNB), and in six of these were the same as the causative organism of the septicemia. Thus, overgrowth of GNB in the gastrointestinal tract may result in invasion of the blood stream and septicemia in immunocompromised patients. To prevent this complication it is necessary to allow the normal intestinal flora to be maintained in these patients as long as possible. Antibiotics should therefore be prescribed with caution. For the same reason, use of immunosuppressive drugs should be kept to a minimum. Bacteriological examination of the stool and pharynx is useful in the management of immunocompromised patients.

K1 antigens, serotypes and antibiotic susceptibilities of Escherichia coli isolates from neonates and infants were investigated. The presence of K1 antigen was tested by the K1‐specific phage method. The number of K1 positive strains was 27 (84%) of 32 isolates from cerebrospinal fluid, 11 (25%) of 44 from blood and 4 (22%) of 18 from other specimens. Fourteen (33%) of the K1 positive strains were serotyped as O16:H6, and 8, 7 and 5 were serotyped as O18ac:H7, O1:H7 and O7:H‐, respectively. One of 5 of the K1 negative strains were distributed into 30 different combinations of O and H antigens. The ampicillin resistance rates were 19% in K1 positive strains and 45% in K1 negative ones. The incidence of chloramphenicol resistance was the same in K1 positive and negative strains (21%). Ampicillin resistance was not noted in O16: H6 strains, but the incidence of antibiotic resistance was high (65% to ampicillin and 53% to chloramphenicol) in the rough‐type strains.