S. M. Hussain Qadri

Controlled study of fluconazole in the prevention of fungal infections in neutropenic patients with haematological malignancies and bone marrow transplant recipients

The efficacy and safety of oral fluconazole versus a polyene regimen in preventing mycoses in neutropenic patients was compared. Patients with haematological malignancy or bone marrow transplantation received as antifungal prophylaxis either fluconazole 200 mg daily or a regimen consisting of clotrimazole trouches 10 mg twice daily with mycostatin, 500,000 i.u. four times daily, benadryl and cepacol mouthwash. Ninety patients at risk for fungus infection were evaluable. Four of 42 patients (9.5 %; confidence interval 2 %–23 %) on fluconazole and 17 of 48 patients (35.4 %; confidence interval 22 %–52 %) (p<0.01) on the clotrimazole regimen developed a clinically significant fungal infection, including 3 (7.1 %) and 11 (22.9 %) patients respectively who had severe fungal infection, mainly pulmonary aspergillosis. Death directly due to a fungal infection within 100 days of the start of prophylaxis occurred in 2 of 42 patients (4.8 %) and 9 of 48 patients (18.8 %) respectively (p<0.06). Kaplan-Meier analysis showed that the chance of survival on fluconazole was statistically greater than for the clotrimazole regimen (p<0.04). A decrease of candidal colonisation of the gastrointestinal and genitourinary tracts occurred only in patients receiving fluconazole. No significant toxicity occurred. A 200 mg daily dose of fluconazole given to these patients thus appears to be well tolerated and to provide a protective effect against the development of fungal infection and death from severe fungal disease.

Evaluation of a modified dye pour-plate auxanographic method for the rapid identification of clinically significant yeasts. Comparison with two commercial systems.

A modified dye pour-plate auxanographic (DPPA) method for the presumptive identification of medically important yeasts was evaluated, in a comparative study with a conventional procedure, the API 20C clinical yeast system (Analytab Products Inc.), and the Uni-Yeast-Tek (UYT) system. The 174 coded clinical isolates were members of the generaCandida, Cryptococcus, Rhodotorula, Saccharomyces, Torulopsis, andTrichosporon. The identification accuracies with DPPA, API, and UYT were 95%, 93%, and 99% respectively. DPPA and API required more time to inoculate but gave rapid identification profiles. UYT was simple to inoculate and both UYT and DPPA were easy to read. Cost analysis of the three rapid methods demonstrated DPPA to be the most economical making it a feasible alternative for small clinical laboratories as well as large laboratories possessing the facilities to make their own media.

Tube carbohydrate assimilation method for the rapid identification of clinically significant yeasts

Yeasts have gained greater recognition in the past several years as being the cause of significant infections. We modified and evaluated a carbohydrate assimilation test to identify yeast isolates rapidly and accurately. The 192 clinical isolates used in this study included 20 species of the generaCandida, Cryptoccoccus, Saccharomyces, Torulopsis, Trichosporon, Rhodotorula, andGeotrichum. The method achieved 95% agreement with standard Wickerham assimilation results, and 97% of the isolates were correctly identified with the aid of a few auxilliary tests. The method is rapid, reliable, and versatile in its use.

Comparative activity of the new fluoroquinolone rufloxacin (MF 934) against clinical isolates of gram-negative and gram-positive bacteria

The antibacterial activity of the new fluoroquinolone rufloxacin (MF 934) was evaluated against 1095 clinical isolates and compared with that of other quinolones and various commonly used antibiotics. Rufloxacin was highly effective against members of theEnterobacteriaceae, inhibiting 98 % of the isolates at a concentration of 1 mg/l. Ninety-two percent ofAeromonas hydrophila and 65 %Acinetobacter strains tested were inhibited by 1 mg/l of rufloxacin, whereas 98 % of methicillin-susceptible and 87 % of methicillin-resistantStaphylococcus aureus strains and 76 % of coagulase-negative staphylococci strains required 4 mg/l for growth inhibition. The MIC values of rufloxacin for most bacteria were 4–16 times higher than those of ciprofloxacin and norfloxacin. Rufloxacin had little activity against xanthomonads, pseudomonads and enterococci. Approximately 95–96 % of isolates ofPseudomonas aeruginosa were inhibited by 2 mg/l of ciprofloxacin and norfloxacin as compared to 29 % inhibited by rufloxacin at this concentration.

Etiology of nosocomial infections and the susceptibility of nosocomial pathogens to imipenem and other antimicrobial agents at a tertiary care referral hospital

Abstract Medical care has changed substantially in the last few decades: todays care often includes aggressive surgical interventions, new instrumentations, catheterizations, organ transplants, and immunosuppressive, irradiation, and chemotherapeutic treatments. These advances have not come without a price. One such cost is an increase in the incidence of nosocomial infections, especially in tertiary care referral and teaching hospitals. This problem is compounded by nosocomial pathogens that acquire resistance to many of the therapeutic agents used to eradicate them. In Saudi Arabia, as in other developing countries, bacterial pathogens are significantly more resistant to commonly used antimicrobial agents than are pathogens found in the western hemisphere. Consequently, we looked at the susceptibility patterns of 585 nosocomial pathogens from 497 patients at a tertiary care center in Riyadh, Saudi Arabia. Imipenem was found to be the most active antimicrobial agent against gram-negative bacteria, followed closely by third-generation cephalosporins, ciprofloxacin, and aminoglycosides. The in vitro activity of imipenem was almost as good as that of vancomycin against gram-positive nosocomial isolates.

Cytomegalovirus detection by biotinylated DNA probes

Clinical specimens from 317 patients suspected of cytomeglovirus infection were examined by immunofluorescence (IF) using monoclonal antibodies and by a biotinylated DNA probe kit after cell culture isolation. Of the 317 samples, 68 were positive by culture isolation. Of these 67 were IF positive when the cytopathic effect (CPE) was 1+ or less, whereas 56 gave positive results with DNA probes when the CPE was 2+. A further 83 specimens were examined directly by immunoperoxidase histopathology (IHP), IF and the DNA probe kit: 26 of these were positive by IHP examination, 25 by IF and only 6 by DNA probes. The sensitivity of the DNA probe kit was not satisfactory when the clinical tissue specimens were directly examined. However, the sensitivity improved considerably to 82% if the specimens were propagated first in cell culture. The IF method detected the virus before and after cell culture isolation equally well (96%–98.5%). Compared to the IF method, the DNA probe kit is costly and requires more labor and time.

Comparative In Vitro Evaluation of Cefepime, an Aminothiazolyl Methoxyamino Cephem

SummaryThe in vitro activity of cefepime, a new aminothiazolyl methoxyamino cephem, was compared with other commonly used antimicrobial agents against 425 strains of Enterobacteriaceae, 138 isolates of other Gram-negative bacilli and 334 strains of Gram-positive cocci. The minimum inhibitory concentrations (MICs) of cefepime were between < 0.03 and 0.5 mg/L for 90% of the Enterobacteriaceae isolates tested, and all 60 isolates of Enterobacter cloacae and Serratia marcescens were inhibited by < 0.03 to 4.0 mg/L of this cephem. Cefepime was the most effective of the drugs tested against Aeromonas hydrophila; its activity against Pseudomonas aeruginosa, Xanthomonas maltophilia and Acinetobacter was comparable to that of ceftazidime and ceftriaxone. All the isolates of methicillin-susceptible Staphylococcus aureus were inhibited by a concentration of cefepime 0.5 to 8.0 mg/L. Cefepime inhibited all 176 isolates of Streptococcus pyogenes, S. agalactiae and S. pneumoniae at concentrations of < 0.015 to 1.0 mg/L. Like other members of its class, it had little or no activity against Xanthomonas, methicillin-resistant S. aureus and enterococci.

Comparative Evaluation of GR 69153, a Catechol-Substituted Cephalosporin

SummaryThe in vitro activity of GR 69153, a new catechol-containing cephalosporin, was compared with other commonly used antibacterial agents against 651 isolates of Enterobacteriaceae, 204 isolates of other Gram-negative bacilli, and 435 isolates of Gram-positive cocci. The minimum inhibitory concentrations of GR 69153 against 90% of tested strains (MIC90s) of Enterobacteriaceae, including the notoriously resistant Serratia marcescens, were between < 0.03 and 1.0 mg/L. It was the most effective of the drugs tested against Pseudomonas aeruginosa. All 170 isolates of methicillin-susceptible Staphylococcus aureus were inhibited at a GR 69153 concentration of 1.0 mg/L. Like other members of its class, it had little or no activity against Xantho-monas, methicillin-resistant S. aureus and enterococci.