The utilization of exogenous nicotinamide adenine dinucleotide (NAD) by Haemophilus parainfluenzae was studied in suspensions of whole cells using radiolabelled NAD, nicotinamide mononucleotide (NMN), and nicotinamide ribonucleoside (NR). The utilization of these compounds by H. parainfluenzae has the following characteristics. (1) NAD is not taken up intact, but rather is degraded to NMN or NR prior to internalization. (2) Uptake is carrier-mediated and energy-dependent with saturation kinetics. (3) There is specificity for the beta-configuration of the glycopyridine linkage. (4) An intact carboxamide groups is required on the pyridine ring. The intracellular metabolism of NAD was studied in crude cell extracts and in whole cells using carbonyl-14C-labelled NR, NMN, NAD, nicotinamide, and nicotinic acid as substrates in separate experiments. A synthetic pathway from NR through NMN to NAD that requires Mg2+ and ATP was demonstrated. Nicotinamide was found as an end-product of NAD degradation. Nicotinic acid mononucleotide and nicotinic acid adenine dinucleotide were not found as intermediates. The NAD synthetic pathway in H. parainfluenzae differs from the Preiss-Handler pathway and the pyridine nucleotide cycles described in other bacteria.

The in-vitro activity of a beta-lactamase inhibitor (clavulanic acid, sulbactam, BL-P2013 or BL-P2090) in combination with ampicillin against 13 isolates of Mycobacterium tuberculosis was determined by broth dilution. The agents were tested in 1:1 molar ratio of ampicillin to beta-lactamase inhibitor. The beta-lactamase inhibitors alone did not inhibit growth at the highest concentration tested. The MIC90 for ampicillin alone was greater than 32 mg/l. Clavulanic acid plus ampicillin was the most active combination with an MIC90 of 11 microM (4 mg/l of ampicillin). The MIC90 of ampicillin in combination with sulbactam, BL-P2013 or BL-P2090 was 23 microM (8 mg/l of ampicillin). A 1:1 ratio of ampicillin to inhibitor was more active than was a 2:1 ratio. The addition of a beta-lactamase inhibitor to ampicillin greatly improves its in-vitro activity against M. tuberculosis.

It is probable that foscarnet contributed to the electrolyte disorders and symptomatology in this patient. Electrolytes must be monitored frequently during foscarnet therapy. Also, concomitant therapy with antianxiety medications that may mask the symptoms of electrolyte disorders should be undertaken with caution.

The addition of FD&C blue dye to enteral feeds is a common practice in hospitals to detect aspiration. However, the degree of systemic absorption and safety of this dye in critically ill patients has not been studied. A patient with sepsis who died after systemic absorption of FD&C blue dye No1 is described.

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