Kinetics of Bacterial Growth in Simple Intravenous Solutions and Admixtures

Abstract

The growth of bacteria in intravenous solutions and admixtures has been studied under stationary conditions of incubation. All the solutions were inoculated with 100 organisms/ml, incubated at room temperature (27 degrees C) or (37 degrees C), with samples withdrawn at specified time intervals, and plated in quadruplicates. The simple intravenous (i.v.) solutions did not support significant growth (P greater than 0.05) of any of the micro-organisms. Growth in i.v. solutions containing 1% blood was very significant (P greater than 0.05), as demonstrated by the high apparent growth rate constants (K). The ratio of K for beta-lactamase producing bacteria (beta-lac+) over that for non-beta-lactamase producing bacteria (beta-lac-) was significant (P less than 0.05) at 37 degrees C compared to that at 27 degrees C. The higher K values for B. cereus in benzylpenicillin and cefuroxime solutions, respectively, compared to those in antibiotic-free solutions, may be attributable to hydrolysis of the drugs, while the low K values for B. subtilis in the same solutions may be attributed to the inhibitory effects of the drugs. In conclusion, minute quantities of blood in i.v. solution tend to cause bacteria to multiply rapidly. The presence of beta-lactamase producing species might, in addition, hydrolyse susceptible beta-lactam antibiotics which are common additives to i.v. fluids.

Central Venous Catheter Infection

“…The ability of an organism to grow in an infusion fluid is dependent upon the pH, osmolality and nutrient availability of the solution (Akpan et al 1989) and temperature, inoculum size and the physiological state of the bacterium (Hoffman et al 1982). All three organisms examined were mesophilic, and able to grow at temperatures of 20 -40°C with an optimum of 37°C.…”

How should we handle epidural solutions? One view

“…Several studies have shown that IV solutions and drugs are at least bacteriostatic 13,14 and, often, bactericidal over time 15 for a wide variety of microorganisms, essentially because they lack the nutrients the bacteria need to survive. One study has shown that refrigerated solutions remain sterile for several months.…”

Επιβίωση Και Πολλαπλασιασμός Μικροβίων Στα Κοινά Ενδοφλέβια Υγρά Και Τα Υγρά Παρεντερικής Διατροφής

“…1) Κοινά βασικά ενδοφλέβια υγρά ή οροί: NaCI 0,9%, γλυκόζη 5% και μικτά Αυτά παρασκευάζονται με αυστηρές προδιαγραφές από ιδιωτικούς συνήθως φορείς, υφίστανται το νόμιμο έλεγχο ποιότητας και διοχετεύονται στο εμπόριο διατηρούμενα σε θερμοκρασία δωματίου. Παρ' όλα αυτά τα μέτρα, δεν είναι λίγες οι περιπτώσεις επιδημιών σηψαιμιών και ενδοτοξικού shock από μολυσμένους ορούς(Akpon et al, 1989). Στα υγρά αυτά, που διατηρούνται σε θερμοκρασία δωματίου, μπορεί να αναπτυχθούν και να πολλαπλασιασθούν τα ελάχιστα μικρόβια που τυχόν διέφυγαν την καταστρεπτική δράση της τελικής αποστείρωσης και να φτάσουν σε υψηλούς αριθμούς cfu/ml.…”