Vibrio cholerae antimicrobial drug resistance, Papua New Guinea, 2009–2011

Cholera is an acute infectious disease caused by Vibrio cholerae . The disease occurs in a variety of forms ranging from sporadic cases to outbreaks that may transition to endemic disease. While cholera case management focuses on early, rapid rehydration, antimicrobial therapy can reduce the volume of diarrhoea, duration of carriage and symptoms and is frequently recommended for patients with severe dehydration.

Distinct synergistic action of piperacillin and methylglyoxal against Pseudomonas aeruginosa.

The dicarbonyl compound methylglyoxal is a natural constituent of Manuka honey produced from Manuka flowers in New Zealand. It is known to possess both anticancer and antibacterial activity. Such observations prompted to investigate the ability of methylglyoxal as a potent drug against multidrug resistant Pseudomonas aeruginosa. A total of 12 test P. aeruginosa strains isolated from various hospitals were tested for their resistances against many antibiotics, most of which are applied in the treatment of P. aeruginosa infections. Results revealed that the strains were resistant to many drugs at high levels, only piperacillin, carbenicillin, amikacin and ciprofloxacin showed resistances at comparatively lower levels. Following multiple experimentations it was observed that methylglyoxal was also antimicrobic against all the strains at comparable levels. Distinct and statistically significant synergism was observed between methylglyoxal and piperacillin by disc diffusion tests when compared with their individual effects. The fractional inhibitory concentration index of this combination evaluated by checkerboard analysis, was 0.5, which confirmed synergism between the pair. Synergism was also noted when methylglyoxal was combined with carbenicillin and amikacin.

Uridine 5'-diphosphate glucose 4-epimerase from Ehrlich ascites carcinoma cells.

Uridine 5'-diphosphate glucose 4-epimerase (EC 5.1.3.2) from Ehrlich ascites carcinoma cells was purified to apparent homogeneity using conventional procedures and NAD-hexane-agarose affinity chromatography. The protein had a molecular weight of 96,000. The ascites enzyme had an absolute requirement for exogenously added NAD (10 μM) for stability. This appears to be a unique feature of ascites epimerase since epimerase from other mammalian sources did not exhibit such a dependence. Exogenously added NAD was also needed for catalysis with an apparent Km value of 2·5 μM. NADH was a very potent competitive inhibitor (K i = 0·11 μM with respect to NAD) of the enzyme activity at pH values close to intracellular pH. The dependence of the enzyme on NAD for stability and its inhibition by NADH may have some potential significance in tumor metabolism.