A study of 245 infected surgical wounds in Singapore.

The aims of the study were to correlate the laboratory detection rate of wound infections with the actual wound infection rate, and to analyse the bacteriology of these wounds to provide a rationale for antibiotic usage in prophylaxis and treatment of surgical wound infections. The wound infection rate in a general surgical unit was determined using the most comprehensive surveillance available to us and was correlated with the laboratory detection rate. A correlation coefficient of 0.8 was obtained, allowing a reasonable estimation of the actual wound infection rate from laboratory data. Review of the bacteriology of consecutive infected surgical wounds over a 4 year period in a university hospital, revealed that the commonest organisms cultured were Staphylococcus aureus, Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, enterococci and beta-haemolytic streptococci. Methicillin-resistant S. aureus (MRSA) caused 50% of all staphylococcal wound infections. All MRSA isolates were sensitive to fusidic acid and vancomycin. All the non-MRSA isolates of S. aureus were sensitive to cephalexin. Some 89% of E. coli were sensitive to gentamicin, with 93% and 100% sensitive to cefuroxime and ceftriaxone respectively. Klebsiella isolates have shown an increased resistance to aminoglycosides, with a new strain from one patient, isolated in 1990, resistant to penicillins, aminoglycosides and third generation cephalosporins. Pseudomonas spp., enterococci and beta-haemolytic streptococci did not show a change in resistance patterns over the same time period.

Ca-channel blockers and the electrophysiology of synaptic transmission of the guinea-pig olfactory cortex.

Slices of guinea-pig olfactory cortex have been used to compare the potency of various Ca-blockers on the electrophysiology of synaptic transmission. Listed in the order of potency, the divalent cations Cd2+, Ni2+, Mn2+, Co2+, La3+ and Mg2+ depressed synaptic transmission. The organic Ca-blockers, nifedipine or nimodipine or verapamil and diltiazem were ineffective up to 0.01 mmol/l. Verapamil, D600 or diltiazem (0.1-0.3 mmol/l) depressed both synaptic transmission and the sodium-mediated presynaptic action potential. These results reaffirm the idea that 'organic Ca-antagonist' do not block all Ca-channels in brain and the high Cd2+ sensitivity suggests the Ca-channels in post- and presynaptic membranes have dissimilar pharmacological profiles.