Behavior of antibiotics during human necrotizing pancreatitis.

The aim of the study was to verify whether antibiotics excreted by the normal pancreas are also excreted in human necrotizing pancreatitis, reaching the tissue sites of the infection. Twelve patients suffering from acute necrotizing pancreatitis were treated with imipenem-cilastatin (0.5 g), mezlocillin (2 g), gentamicin (0.08 g), amikacin (0.5 g), pefloxacin (0.4 g), and metronidazole (0.5 g). Serum and necrotic samples were collected simultaneously at different time intervals after parenteral drug administration by computed tomography-guided needle aspiration, intraoperatively, and from surgical drainages placed during surgery. Drug concentrations were determined by microbiological and high-performance liquid chromatography assays. All antibiotics reached the necrotic tissues, but with varying degrees of penetration, this being low for aminoglycosides (13%) and high in the case of pefloxacin (89%) and metronidazole (99%). The concentrations of pefloxacin (13.0 to 23 micrograms/g) and metronidazole (8.4 micrograms/g) in the necrotic samples were distinctly higher than the MICs for the organisms most commonly isolated in this disease; the concentrations in tissue of imipenem (3.35 micrograms/g) and mezlocillin (8.0 and 15.0 micrograms/g) did not always exceed the MICs for 90% of strains tested, whereas the aminoglycoside concentrations in necrotic tissue (0.5 microgram/g) were inadequate. Repeated administration of drugs (for 3, 7, 17, and 20 days) seems to enhance penetration of pefloxacin, imipenem, and metronidazole into necrotic pancreatic tissue. The choice of antibiotics in preventing infected necrosis during necrotizing pancreatitis should be based on their antimicrobial activity, penetration rate, persistence, and therapeutic concentrations in the necrotic pancreatic area. These requisites are provided by pefloxacin and metronidazole and to a variable extent by imipenem and mezlocillin.

A simplified method for the evaluation of human faecal flora in clinical practice.

Qualitative and quantitative evaluation of aerobic and anaerobic faecal flora was determined by a new and easy method. 10 microliter of 12 ten-fold dilutions in saline of samples of faeces were plated on the surface of culture media solidified in wells of sterile virology plexiglass plates (diameter 16 mm; 0.5 ml culture media) and incubated at 37 degrees C for 24 h. The same dilutions and the same plexiglass plates were used under anaerobic conditions for analysis of anaerobic flora (under atmosphere of N2 85%, CO2 10%, H2 5%, negative pressure, at 37 degrees C for 48 h). The analysis was performed on 35 healthy breast-fed newborn infants, 1--6 days old. After birth, the meconium in sterile; already at 25 h of life some bacterial species (Lactobacilli, Bifidobacteria, Bacteroides) show the maximal concentration in faeces and do not grow afterwards; other bacterial species (Coliforms, aerobic and anaerobic Streptococci) increase gradually during the first week of life. This method gives the same results as the conventional techniques (i.e. Petri dishes), but in an easier and quicker way; therefore it seems useful in clinical practice.