Franklin P. Koontz

Multicenter comparison of the high volume (10 ml) NR BACTEC PLUS system and the standard (5 ml) NR BACTEC system

This multicenter study was designed to compare the new BACTEC PLUS system (nonradiometric), which utilizes an 8- to 10-ml blood inoculum in a resin-containing medium, to the standard BACTEC (nonradiometric) without resins and 5-ml blood inoculum. There were 12,341 compliant sets studied, yielding 1331 positives, with 1099 sets deemed clinically significant. Overall the BACTEC PLUS showed an enhanced recovery of 33% (p less than 0.001) over its standard counterpart, with significant yield increased in the staphylococci (p less than 0.001), streptococci (p less than 0.002), pseudomonads (p less than 0.002), Enterobacteriaceae (p less than 0.001), and other aerobic Gram negatives (p less than 0.02). The enhanced performance increased to 53% if the patient was receiving any antibiotics at the time the blood was cultured. In patients known to be free of antibiotics at the time of blood draw, there was still an increased yield of 18%. The new system detected positivity at least one reading sooner than twice as often as the converse, and confirmed septic episodes significantly more often (21% overall) (41% on antibiotics) (15% no antibiotics). The BACTEC PLUS has distinct advantages over its low blood volume, nonresin counterpart.

Cefdinir (FK482), an orally administered cephalosporin in vitro activity comparison against recent clinical isolates from five medical centers and determination of MIC quality control guidelines

Cefdinir, a new oral cephalosporin, was compared to cefaclor, cefadroxil, cefixime, and cefuroxime against greater than 5000 recent aerobic clinical isolates. This multicenter study revealed broad-spectrum cefdinir activity against all Enterobacteriaceae (MIC50s, 0.06-2 micrograms/ml) except Enterobacter cloacae, Morganella morganii, Proteus vulgaris, and Serratia marcescens (MIC50s, greater than or equal to 4 micrograms/ml). Oxacillin-susceptible staphylococci (MIC90s, 0.5-2 micrograms/ml), beta-hemolytic Streptococcus group B (MIC90, 0.06 micrograms/ml), and Acinetobacter lwoffii were also susceptible to cefdinir. The activity of cefdinir was similar to that of cefixime and cefuroxime against Gram-negative organisms and superior to all tested oral cephems when tested against Gram-positive cocci. None of the cephalosporins were active against oxacillin-resistant Staphylococcus spp., enterococci, Pseudomonas spp., or Xanthomonas maltophilia. MIC quality control range guidelines were established for the strains recommended by the National Committee for Clinical Laboratory Standards documents.

Toxic Shock Syndrome: A Retrospective Study of 25 Cases from Iowa

We reviewed retrospectively the clinical records of 25 women ages 13 to 41 years who had diagnosed illnesses compatible with toxic shock syndrome (TSS). Cases occurred between January 1976 and October 1980. Fourteen confirmed TSS cases and 11 probable TSS cases were identified.In each case initial symptoms occurred in association with menstrual bleeding and tampon use. All patients were febrile. Hypotension occurred in 20 cases, but five patients with milder illness remained normotensive. An erythematous rash occurred in 20 cases. Desquamation occurred in convalescence in all but two cases. Complications included delirium or coma, acute renal failure, and respiratory distress syndrome. Thirteen patients had recurrences of TSS. S. aureus was isolated from the vagina or cervix in 75% of cases. There is a spectrum of severity associated with TSS. Strict diagnostic criteria established heretofore for epidemiologic studies of TSS may not be met by all cases of TSS.

CI-960 (PD127391 or AM-1091), sparfloxacin, WIN 57273, and isepamicin activity against clinical isolates of Mycobacterium avium-intracellularae complex, M. chelonae, and M. fortuitum

A 7H9 broth microdilution method against CI-960, sparfloxacin, WIN57273, ciprofloxacin, norfloxacin, isepamicin, amikacin, kanamycin, ethambutol, isoniazid, and rifampin was used to test 35 Mycobacterium avium-intracellulare complex (MAI) and five M. chelonae-fortuitum strains. The majority of MAI isolates were inhibited by all tested compounds, with sparfloxacin (MIC90, 0.5 micrograms/ml) being the most active among the fluoroquinolones; isepamicin (MIC90, 4 micrograms/ml), the most potent aminoglycoside; and isoniazid, rifampin, and ethambutol also demonstrating some degree of activity. Mycobacterium chelonae strains were resistant to all drugs except ciprofloxacin (MIC50, 1 microgram/ml). Mycobacterium fortuitum isolates were generally susceptible, especially to the newer fluoroquinolones.

Improved urine screening using a combination of leukocyte esterase and the lumac system

Three rapid urine screening tests, leukocyte esterase, nitrite, and the Lumac System for detection of bacterial ATP, were evaluated alone and in combination to determine their utility in screening urine specimens from male patients for bacteruria. The combination of leukocyte esterase and Lumac testing resulted in significant improvement in the sensitivity of urine screening over each test individually and the combination of leukocyte esterase and nitrite. The leukocyte esterase/Lumac combination detected 98% of those specimens with greater than or equal to 10(5) CFU/ml and had a negative predictive value of 99%. The results obtained from this type of testing can be used with confidence to minimize the number of urine specimens cultured and to provide rapid reporting of negative results.

793 EVALUATION OF QUANTITATIVE CULTURES OF SPUTUM FROM CHILDREN WITH CYSTIC FIBROSIS

Eighty-three sputa were obtained from 41 children with cystic fibrosis and maintained on ice until culture within 20 minutes. Quantitative cultures (QNC) were made by inoculating serial 10-fold dilutions of the sputum, homogenized with N-acetyl cysteine, onto blood, chocolate, and eosin methylene blue agar plates. The same sputum samples were then cultured qualitatively (QLC) on the same types of agar. An average of 3.9 bacterial species per sample in a concentration of ≥ 104 CFU/ml were recovered by QNC. Organisms which might be considered “normal flora” were recovered from 57 QNC and 80 QLC. Potential pathogens were recovered from 80 QNC and from 74 QLC. S. aureus, present in QNC in a mean concentration of 3.2 × 107/ml, was recovered from 31 sputum pairs and additionally from 1 QNC and 2 QLC. Ps. aeruginosa, present in QNC in an average concentration of 1.9 × 108/ml,was recovered by both methods 55 times, 3 additional times each by QNC and QLC. H. influenzae was present in QNC in a mean concentration of 3.4 × 108/ml and was recovered by both culture techniques 9 times. It was recovered 26 additional times by QNC and 2 additional times by QLC. In 24 of 24 instances, the H. influenzae recovered by QNC was not typable by counter immunoelectropheresis. Routine qualitative sputum cultures underestimate the frequency with which H. influenzae may be recovered from children with cystic fibrosis.

Antimicrobial activity of RU29246 (HR916 metabolite) compared with four other oral beta-lactams tested against more than 5000 clinical isolates

The activity of RU29246, the active metabolite of the oral cephalosporin ester HR916, was compared in a multicenter study with that of the four oral beta-lactam antibiotics cephalexin, cefaclor, cefixime and amoxicillin/clavulanate (amoxicillin/CA). RU29246 was generally 2- to 8-fold more active than the other oral cephalosporins and comparable to amoxicillin/CA against staphylococci, and was the most active cephalosporin against group B streptococci. All four cephalosporins were ineffective against enterococci. RU29246 was the only cephalosporin consistently active againstAcinetobacter, but all beta-lactam antibiotics had poor activity againstPseudomonas spp. andXanthomonas maltophilia. RU29246 was comparable to cefixime and more active than the other cephalosporins against members of the familyEnterobacteriaceae. However, all of the antibiotics had poor activity againstEnterobacter cloacae andSerratia marcescens. Quality control reference ranges for the quality control organismsStaphylococcus aureus ATCC 29213 andEscherichia coli ATCC 25922 are proposed for the broth dilution method based on data derived from this multicenter study.