Prevalence of Bacterial Pathogens and Susceptibility Patterns from clinical sources in Trinidad

During a 12-month period (January-December, 1997), bacterial isolates of specimens from in-patients and out-patients of the Eric Wiliams Sciences Complex (EWMSC) were reviewed. A total of 3,513 specimens were processed, 43.1 percent from in-patients and 56.9 percent from out-patients. Of the 3,513 specimens, 1,129 (32.1 percent) yielded positive cultures. Micro-organisms from wounds, sputum and genital tract accounted for 90.2 percent, 51.5 percent and 31.8 percent, respectively, of all isolates. E coli (17.4 percent) and Enterococci (12.2percent) were the predominant isolates and were also the major pathogens from blood stream infections, 25.8 percent and 18.2 percent, respectively, followed by P aeruginosa, 15.2 percent. High levels of resistance were seen to ampicillin, augmentin (amoxicillin-clavulanic acid) and tetracycline. The most effective antibiotics were ceftazidime (no resistance in E coli Citrobacter spp, non-typhoidal Salmonella and Group B streptococci, 63.2 percent resistance in Acinetobacter spp, 15.2 percent in Enterobacter spp, 17.4 percent in Klebsiella spp.], erythromycin (no resistance in Enterobacter and Citrobacter spp, and 89.5 percent in Acinetobacter (spp), erythromycin (no resistance in Groups A and B streptococci, 85.1 percent in S aurens and S pneumoniae). The spectrum of isolates will provide clinicians with data on which to base their "best guess" aetiologic agent and choice of antibiotics when faced with infectious diseases in areas where laboratory assistance is not readily available.(Au)

Pharmacoeconomics of intravenous antibiotic use in serious infection - abstract

A pharmacoeconomic study of 15 antibiotics available in Barbados was performed. The antibiotics studied were amoxycillin/clavulanate, ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, ceftazidime, ceftriaxone, clindamycin, cloxacillin, co-trimoxazole, gentamicin, irnipenem, metronidazole, piperacillin, piperacillin/tazobactam, and vancomycin. The costs of use of these compounds using a formula comprising eight categories: antibiotic purchase cost, maintenance of IV access, drug delivery cost, drug monitoring cost, dose readjustment, general monitoring cost, sharps disposal cost and adverse effects. The costs of adverse effects were not included in this study due to lack of accurate data. The total costs of antibiotic use (in Barbados dollars) ranged from $85.04 to $927.46 per five-day course. Generic compounds were less expensive ($85.04 - $236.02) than brand-name compounds ($212.25 - $927.46). Antibiotic purchase costs accounted for proportions of total costs ranging from 7 per cent to 93 per cent. Non-drug costs represented a much greater proportion of total costs of generic compounds. For most compounds the non-drug costs were related to the frequency of dosing, but for gentamicin the non-drug costs were relatively higher because of the need for monitoring serum gentamicin levels. Efficacy and freedom from side-effects will remain the most important determinants in the choice of antibiotic therapy. However, pharmacoeconomic analyses can provide clinicians with the information required to make cost-effective choices for treatment of their patients (AU)

In vitro activity of ceftazidime and other antipseudomonal antibiotics against mucoid strains of pseudomonas aeruginosa

The minimum inhibitory concentration of ceftazidime, was determined for 132 mucoid strains of pseudomonas aeruginosa (MPA) isolated from patients with cystic fibrosis (CF), using an agar tube dilution method. Using strains collected over a ten-year period, we found that 98 percent were susceptible to achievable serum concentrations with MIC50 and MIC90 of 1.2 and 3.1 ug/ml, respectively. Susceptibility of 60 of these strains was also determined for cefoperazone (100 percent susceptible), tobramycin (97 percent), and carbenicillin (83 percent). Susceptibility of stored strains was similar to that of fresh isolates. We have shown that strains of MPA in a U.S. population were more susceptible to ceftazidime than those currently reported from Europe where this antibiotic was introduced earlier. Cefoperazone, another third generation cephalosporin which has received less attention in the treatment of patients with CF, is as active as ceftazidime in vitro. These data provide a basis for determining the future impact of these agents on pseudomonas susceptibility (AU)