Aberrant Histoplasma capsulatum. Confirmation of identity by a chemiluminescence-labeled DNA probe

A cottony, light tan, filamentous fungus with pear-shaped microconidia and lacking tuberculated macroconidia was isolated from a bronchial lavage specimen. Subculture on several media at 37 degrees C failed to convert the fungus to a yeast form after several weeks; attempts at in vivo conversion in mice were also unsuccessful. Sera obtained several months apart showed M bands with Histoplasma capsulatum (HC) antigen by immunodiffusion and an increase in complement fixation titers with mycelial and yeast phase antigens of HC. Parallel identity was obtained on two occasions with exoantigen culture confirmation reagents for HC from Immuno-Mycologics as well as one of identity with Nolan reagents. Extracts from four Chrysosporium spp. strains had no identity reactions with HC with either kit. The fungus was identified as HC by the Accuprobe Histoplasma chemiluminescence-labeled DNA probe directed at ribosomal RNA, whereas all four Chrysosporium spp. isolates tested negative. DNA probes are a fast and accurate method to confirm the identity of aberrant fungal isolates.

In vitro comparison activity of OPC-17116, a new fluoroquinolone, against more than 5,000 recent clinical isolates from five medical centers

The in vitro activity of OPC-17116, a new fluoroquinolone, was compared with those of ciprofloxacin, ofloxacin and cefixime. A total of 5,231 fresh clinical isolates from five geographically separate US medical centers were tested. The primary results of this study are: 1. OPC-17116 is very active against Enterobacteriaceae [MIC90s, 0.015-1 microgram/ml, except Providencia rettgeri (MIC90, > 8 micrograms/ml)], 2. among nonenteric Gram-negative bacilli (e.g. Xanthomonas maltophilia, MIC90, 2 micrograms/ml) and Gram-positive cocci (e.g. oxacillin-susceptible staphylococci, MIC90s, 0.12-0.5 microgram/ml) OPC-17116 demonstrated higher activity than ciprofloxacin or ofloxacin, 3. the quinolones were more active than cefixime against most of the species tested, especially against Gram-positive and non-enteric Gram-negative organisms. The results of this study, associated with prior documented favorable qualities, support continued investigation of OPC-17116 for clinical use.

Controlled clinical comparison of two lysis-based blood culture systems, isolator and Septi-Chek Release, for detection of bloodstream infections

A controlled clinical comparison was made of the Isolator (Wampole Laboratories, Cranbury, N.J.) and the Septi-Chek Release bottle (Roche Diagnostics, Nutley, N.J.). From 6,345 blood culture sets fulfilling minimum criteria for volume of blood cultured, 840 strains were isolated, of which only 691 (82%) were considered to be representative of bloodstream infection according to Centers for Disease Control definitions. Statistically significant differences were found between the systems for the following organisms, which were all detected more frequently in the Isolator system: Staphylococcus aureus (P = 0.0001), Alcaligenes xylosoxidans (P = 0.008), Klebsiella pneumoniae (P = 0.05), Salmonella spp. (P = 0.03), and Candida albicans (P = 0.02). The Septi-Chek Release system required a longer period of time than the Isolator system for detection of the following organisms:S. aureus (P = 0.0001), Enterococcus spp. (P = 0.0001), Enterobacter cloacae (P = 0.03), Escherichia coli (P = 0.0001), Klebsiella oxytoca (P = 0.03), K. pneumoniae (P = 0.02), Pseudomonas aeruginosa (P = 0.002), and C. albicans (P = 0.005). There were 430 episodes of bloodstream infections identified in the study; of these episodes, only those due to S. aureus were detected significantly more frequently (P = 0.0001) by the Isolator system than by the Septi-Chek Release system. However, episodes of bloodstream infections due to S. aureus, Staphylococcus epidermidis, Enterococcus spp., and E. coli were detected significantly faster by the Isolator system.

Multicenter comparison of in vitro activities of FK-037, cefepime, ceftriaxone, ceftazidime, and cefuroxime

In a multicenter study, the MICs of FK-037 for 90% of the strains tested (MIC90s) were < or = 1 microgram/ml for members of the family Enterobacteriaceae other than Citrobacter freundii, Enterobacter spp., and Serratia marcescens. Activity against Pseudomonas aeruginosa was variable, with a MIC50 and a MIC90 of 4 and 32 micrograms/ml, respectively. Relative to cefepime, however, FK-037 was less active against ceftazidime-resistant isolates of Enterobacter cloacae. The MIC90 of FK-037 for methicillin-resistant staphylococci was > 16 micrograms/ml.

In vitro activity of cefpodoxime compared with other oral cephalosporins tested against 5556 recent clinical isolates from five medical centers

A multicenter study was conducted in which the in vitro activity of cefpodoxime (the active metabolite of the prodrug ester cefpodoxime proxetil) was compared with those of cefixime, cefuroxime, cefaclor, cefadroxil, and clarithromycin against 5556 recent clinical isolates. Cefpodoxime demonstrated potent activity against members of the Enterobacteriaceae, in particular against species generally resistant to the established oral cephalosporins such as Proteus vulgaris [minimum inhibitory concentration (MIC)50, 0.12 microgram/ml], Providencia rettgeri (MIC50, 0.015 microgram/ml), and Serratia marcescens (MIC50, 2 micrograms/ml). Cefpodoxime was very effective against the fastidious organisms most frequently associated with respiratory infections, such as Streptococcus pneumoniae (MIC90, 0.12 microgram/ml), Haemophilus influenzae (MIC90, 0.12 microgram/ml), and Moraxella catarrhalis (MIC90, 1 microgram/ml). In contrast to other orally administrated third-generation cephalosporins (cefixime or ceftibuten), cefpodoxime demonstrated reasonable activity against oxacillin-susceptible staphylococci, with MIC50 ranging from 1 to 2 micrograms/ml. All cephalosporins tested demonstrated poor activity against Pseudomonas spp., Xanthomonas spp., Enterococcus spp., and oxacillin-resistant staphylococci. Cefpodoxime had the widest spectrum of activity of all tested oral cephalosporins.

Comparison of vidas Clostridium difficile toxin-A assay and premier C. difficile toxin-A assay to cytotoxin-B tissue culture assay for the detection of toxins of C. difficile

Damage to the intestinal mucosa by Clostridium difficile (CD) is toxin mediated. Two enzyme immunoassays (EIAs) for toxin-A detection, the automated Vitek immunodiagnostic assay system CDA (Vidas CDA), and the Premier toxin A (Premier) were tested for their ability to detect toxin A in 301 stool samples and compared with an in-house tissue culture assay for toxin B (TCA). Of these 301 samples, 49 were TCA positive and 252 were TCA negative. Agreement between Vidas CDA and TCA on the initial run was 85% (255 of 301) and increased to 94% (278 of 296) when discordant samples were retested from available frozen specimens. Corresponding levels of agreement for Premier were 91% (272 of 301) and 98% (284 of 288), respectively. If tissue culture positivity at any titer was used as the sole criterion for positivity of the specimen, agreement with positive TCA before and after repeat testing was 57% (26 of 49) and 74% (34 of 46) for Vidas CDA and 65% (32 of 49) and 95% (36 of 38) for Premier. Agreement with negative TCA titers was good: 90% for Vidas CDA and 95% for Premier, and 98% for Vidas CDA and 99% for Premier after repeat testing. Predictive values positive and negative after repeat testing were, respectively, 88% and 96% for Vidas CDA, and 95% and 99% for Premier. Results for the automated and manual EIA methods for detection of C. difficile toxin A were obtained in 2.5 h as compared with 36-48 h for tissue culture.

Ceftazidime resistance in Hafnia alvei

Two morphotypes of Hafnia alvei differed in their susceptibilities to beta-lactam antibiotics. Both produced an inducible Bush group 1 beta-lactamase. Hyperinducibility of this enzyme was associated with reduced susceptibility in one morphotype.

Unpredictability of commercially available exoantigen culture confirmation tests in confirming the identity of five Blastomyces dermatitidis isolates

Colonial and microscopic features of five fungal isolates from three patients suggested Blastomyces dermatitidis. Extracts from the mold forms of all isolates were tested on several occasions with commercially available Exoantigen immunodiffusion culture-confirmation test reagents and Nolan reagents. All three isolates from patient 1 were negative on four separate attempts with Exoantigen reagents using conventional ("slant") and "broth" extraction methods, and were also negative on one attempt with the Nolan reagents. The isolate from patient 3 was negative on three attempts using both reagent kits. The isolate from patient 2 was negative on four of five attempts with Exoantigen test reagents and positive on one attempt with Nolan reagents. Commercially prepared chemiluminescence-labeled DNA probes (Gen-Probe, San Diego, CA) directed at ribosomal RNA from B. dermatitidis and Histoplasma capsulatum confirmed all five isolates as B. dermatitidis. The cost and labor of the exoantigen and DNA Probe culture confirmation tests were evaluated. New methods for confirming the identity of cultural isolates of B. dermatitidis that are sensitive, specific, and commercially available are greatly needed.

Access behaviors of children with specific language impairment

The verbal and nonverbal behaviors used by 5 children with specific language impairment (SLI) to attempt to gain access into established interactions were described and compared with those of chronological-age-mates and language-similar control subjects. Three of the children with SLI were unsuccessful. Two of the children with SLI achieved access but did so without using linguistic forms like those most normal-language children use. All of the children with normal language accessed, and most did so quickly and easily using an orderly and sequential set of indirect behaviors. The findings contribute to social-linguistic characterizations of SLI and clarify specific aspects of access described in the normal-language literature.

Selective bowel decontamination with quinolones and nystatin reduces gram-negative and fungal infections in orthotopic liver transplant recipients

Gram-negative and fungal infections are the most important cause of morbidity and mortality after liver transplantation, especially in the first postoperative month. From February 1989 to February 1990, all liver transplant recipients at The Cleveland Clinic Foundation, Cleveland, Ohio, were placed on a selective bowel decontamination regimen employing oral quinolones and nystatin beginning at the time they were put on the active waiting list for transplantation and continuing until the fourth postoperative week. The incidence of gram-negative and fungal infections for these patients was compared against a historical control group. Selective bowel decontamination was well tolerated and highly effective in reducing early serious gram-negative and fungal infections. This regimen may also reduce mortality.

An international multicenter study of blood culture practices. The International Collaborative Blood Culture Study Group

An international study was organized to review blood culture practices in 67 medical centers, most of which were teaching hospitals with a total of over 58,000 active hospital beds. The number of blood cultures per admission was generally greater than 0.5 in the USA and less than 0.5 in other countries. Criteria varied for defining a septic episode, as well as for ascribing clinical importance to isolates of coagulase-negative staphylococci; however, septicemia rates tended to be lower in centers in which clinical evaluation was included among these criteria. Staphylococci were ranked first or second among etiologic agents of septicemia in the USA, whereas Escherichia coli was most frequently ranked first among European and Asian centers. All USA centers recommended collection of two blood cultures per septic episode and all but one recommended a maximum number of blood cultures per septic episode, whereas similar recommendations were less common in Europe and Asia. Collection of more than 10 ml per blood culture was more common in the USA than in Europe or Asia. A variety of broth-based systems were used, often in combination with lysis-centrifugation for special (fungal, mycobacterial) or, on occasion, routine purposes.

General guidelines for clinical bacteriology. Infectious Diseases Society of America and the Food and Drug Administration

This guideline summarizes recommendations for (1) developing cogent procedures for diagnosis and antimicrobial susceptibility testing; (2) developing quality-control parameters for the microbiological components of clinical trials; (3) continually updating U.S. Food and Drug Administration (FDA) guidelines; (4) reviewing microbiological recommendations from other groups, such as Microbiology Subcommittees of the National Committee for Clinical Laboratory Standards; and (5) improving the microbiological aspects of FDA package inserts for antimicrobial drugs. Sensitive and specific methods for isolation and identification of pathogens are essential to the proper conduct of clinical trials. Susceptibility tests should be performed in an accurate and reproducible fashion. Verification of results in a reference laboratory is encouraged to monitor quality control.

Evaluation of a chemiluminescent probe assay for identification of Histoplasma capsulatum isolates

Fifty-three of 54 isolates of fungi were correctly identified with an acridinium ester-labelled probe for Histoplasma capsulatum (Accuprobe; Gen-Probe, San Diego, Calif.). One isolate of Aspergillus niger was incorrectly identified as H. capsulatum. Age of the culture, medium for isolation, and morphologic state did not affect the results.

Cefmetazole and trospectomycin in vitro susceptibility testing interpretive criteria and quality control guidelines for Neisseria gonorrheae

Cefmetazole and trospectomycin were tested in a multilaboratory trial to establish Neisseria gonorrhoeae susceptibility testing criteria and quality control (QC) guidelines. Cefmetazole was active against the penicillinase-producing isolates and has an MIC90 of 16 micrograms/ml, the breakpoint MIC previously used for nonfastidious species. However, a single-dose gonorrhea regimen (1 g i.m.) would require a lower less than or equal to 2 micrograms/ml breakpoint with a correlate zone (greater than or equal to 33 mm) consistent with similarly used cephamycins (cefoxitin and cefotetan). An intermediate category was proposed for MICs greater than 2-4 micrograms/m (28-32 mm) pending more clinical experience with higher and/or prolonged cefmetazole dosing regimens. Trospectomycin was active (MIC90, 8 micrograms/ml) against all spectinomycin-susceptible gonococci. A susceptible breakpoint MIC of less than or equal to 16 micrograms trospectomycin per milliliter was proposed with a correlate zone diameter of greater than or equal to 17 mm. An intermediate category was also suggested for trospectomycin at 32 micrograms/ml (14-16 mm). QC guidelines were established for 30-micrograms cefmetazole and 30-micrograms trospectomycin disk diffusion tests and the GC agar base MICs using a multilaboratory study design consistent with National Committee for Clinical Laboratory Standards (NCCLS) M23-T guidelines. Both drugs were stable in GC agar plates for 21 days stored at 2 degrees-5 degrees C.

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.

Proposed interpretive criteria and quality control parameters for testing susceptibility of Neisseria gonorrhoeae to beta-lactam-clavulanate combinations

To support future clinical studies, in vitro susceptibility tests were examined to determine whether Neisseria gonorrhoeae could be tested reliably against two beta-lactam-clavulanate combinations. All isolates that were tested appeared to be susceptible to amoxicillin and ticarcillin in combination with clavulanic acid. In the absence of resistant isolates, only a breakpoint for a susceptible category could be defined for agar dilution tests with amoxicillin-clavulanic acid (MIC of less than or equal to 2.0/1.0 micrograms/ml is tentatively proposed). For disk diffusion tests, a corresponding breakpoint zone diameter of greater than or equal to 28 mm is suggested. The validity of the breakpoints for penicillinase-negative penicillin-resistant strains awaits clinical data. Proposed quality control limits for testing amoxicillin-clavulanic acid by agar dilution and disk diffusion methods are a MIC of 0.25/0.125 to 1.0/0.5 micrograms/ml and zones of 30 to 40 mm in diameter for N. gonorrhoeae ATCC 49226, a MIC of 0.125/0.06 to 0.5/0.25 micrograms/ml for Staphylococcus aureus ATCC 29213, and zones of 30 to 38 mm for S. aureus ATCC 25923. Ticarcillin-clavulanate is currently tested against other species by preparing doubling dilutions of ticarcillin with a constant 2 micrograms of clavulanate per ml. By that method, all gonococci were susceptible to low concentrations. However, the amount of clavulanic acid that is included (2 micrograms/ml) will, by itself, inhibit many strains of N. gonorrhoeae. Consequently, the role of ticarcillin in the combination cannot be determined, and such tests are not recommended.

MIC and disk diffusion quality control guidelines for Neisseria gonorrhoeae susceptibility tests of cefdinir, cefetamet, CI-960, fleroxacin, lomefloxacin, and temafloxacin

Cefdinir (FK482), cefetamet (Ro 15-8074), CI-960, fleroxacin, lomefloxacin, and temafloxacin have potent activities against Neisseria gonorrhoeae. They were tested in a multilaboratory study to establish quality control guidelines. Quality control ranges for N. gonorrhoeae ATCC 49226 were determined by using multiple GC agar lots, three disk lots, and a number of test replicates consistent with the M23-T guidelines of the National Committee for Clinical Laboratory Standards. The MIC ranges included 2 to 4 log2 dilution steps. The recommended inhibition zone diameter ranges were generally 7 to 8 mm and included greater than or equal to 91.3% of all recorded study results.

Interpretive criteria and quality control limits for testing susceptibility of Neisseria gonorrhoeae to enoxacin

For testing the susceptibility of Neisseria gonorrhoeae to enoxacin, a proposed susceptibility category includes strains for which MICs are less than or equal to 0.5 micrograms/ml and zones of inhibition are greater than or equal to 32 mm in diameter. Because of the sparcity of resistant gonococci, a resistance category was not defined, but laboratory-selected resistant mutants were appropriately categorized by the proposed criteria. A review of clinical data confirmed the utility of a single 400-mg oral dose of enoxacin for treating gonorrhea caused by strains judged to be susceptible by the proposed criteria. For quality control purposes, for N. gonorrhoeae ATCC 49226 MICs should be 0.016 to 0.06 micrograms/ml and zones of inhibition should be 43 to 51 mm in diameter.

Proposed interpretive criteria and quality control parameters for ofloxacin susceptibility testing of Neisseria gonorrhoeae

A multilaboratory study designed to determine the in vitro susceptibility criteria and quality control parameters for ofloxacin against Neisseria gonorrhoeae was conducted according to the guidelines of the National Committee for Clinical Laboratory Standards. Proposed susceptibility breakpoints are MICs of less than or equal to 0.25 microgram/ml for the agar dilution test and greater than or equal to 31 mm for the disk diffusion test. A category for resistance could not be defined. Proposed acceptable quality control MICs for N. gonorrhoeae ATCC 49226 and Staphylococcus aureus ATCC 29213 range from 0.004 to 0.03 microgram/ml and 0.25 to 1.0 microgram/ml, respectively. With 5-micrograms ofloxacin disks, acceptable inhibitory zone diameters for S. aureus ATCC 25923 and the N. gonorrhoeae control strains range from 22 to 27 mm and 43 to 51 mm, respectively.

Multicenter evaluation of the use of Haemophilus test medium for broth microdilution antimicrobial susceptibility testing of Streptococcus pneumoniae and development of quality control limits

A five-laboratory collaborative study was undertaken to determine the precision and accuracy of broth microdilution susceptibility tests of Streptococcus pneumoniae isolates performed with Haemophilus test medium (HTM) compared with tests performed with lysed horse blood-supplemented Mueller-Hinton broth (LHB). The intra-and interlaboratory reproducibilities of MICs of 10 antimicrobial agents determined with the two media were found to be quite similar and highly reproducible in both media. On the basis of favorable performance in this study, S. pneumoniae ATCC 49619 is recommended as a quality control strain to assess the performance of HTM when this medium is used for testing of pneumococci. Testing of 293 unique clinical isolates of S. pneumoniae with both media in the respective participant laboratories allowed a direct comparison of MIC results and a calculation of interpretive error rates. Although there were some slight differences between MICs determined with HTM and MICs determined with LHB, few very major or major errors resulted from testing the clinical isolates against the 10 antimicrobial agents. However, MIC-interpretive criteria specific for S. pneumoniae should be developed and promulgated through a national consensus mechanism.

Revision of standards for adjusting the cation content of Mueller-Hinton broth for testing susceptibility of Pseudomonas aeruginosa to aminoglycosides

A multilaboratory study was undertaken to reassess the amount of calcium and magnesium that should be added to Mueller-Hinton broth when testing Pseudomonas aeruginosa against amikacin, gentamicin, isepamicin, netilmicin, and tobramycin. To achieve parity with agar dilution tests, cation-adjusted broth should contain 20 to 25 mg of calcium and 10 to 12.5 mg of magnesium per liter rather than the 50- and 25-mg/liter supplements recommended previously. For quality control of tests with contemporary media, MIC control limits should be adjusted by lowering the current MIC limits by at least 1 doubling-dilution interval.

Cytogenetic abnormalities in an ossifying fibroma from a patient with bilateral retinoblastoma

Cytogenetic analysis of a cemento-ossifying fibroma from a patient with nonfamilial bilateral multicentric retinoblastoma revealed three reciprocal translocations with the karyotype 46,XY,t(1;18)(q21;q21.3),t(3;10)(p13;q22),t(6;11)(p22;p15). Routine and high-resolution cytogenetic analysis of peripheral blood leukocytes showed an apparently normal, 46,XY chromosome pattern with no deletion of chromosome 13. Molecular analysis demonstrated no gross differences in the retinoblastoma gene or the TP53 gene between constitutional and tumor DNA. This is the first cytogenetic analysis of a cemento-ossifying fibroma and the first report of this tumor in a retinoblastoma patient. The data may be added to the small, but growing literature on cytogenetic aberrations in benign tumors and may lend insight into genes involved in cell proliferation and neoplastic transformation.

Disk diffusion quality control guidelines for Haemophilus susceptibility tests using cefdinir, CI-960, fleroxacin, temafloxacin, and trospectomycin

A multilaboratory study to determine disk diffusion quality control ranges for Haemophilus influenzae ATCC 49247 and five investigational drugs was performed. Multiple lots of Haemophilus Test Medium and antibiotic disks were used for replicate testing in conformance with the recommendations of the National Committee for Clinical Laboratory Standards. Quality control disk zone diameter ranges were proposed for cefdinir, CI-960, fleroxacin, temafloxacin, and trospectomycin.

Interpretive criteria and quality control guidelines for lomefloxacin and meropenem in susceptibility tests of Haemophilus influenzae using Haemophilus test medium

Lomefloxacin and meropenem were tested in a multilaboratory study to establish susceptibility testing interpretive criteria and quality control (QC) guidelines for Haemophilus influenzae using Haemophilus test medium (HTM). Interpretive criteria were established by using triplicate testing of 102 representative H. influenzae strains. Only a susceptible category was proposed for lomefloxacin (greater than or equal to 22 mm and less than or equal to 2 micrograms/ml) and meropenem (greater than or equal to 13 mm and less than or equal to 4 micrograms/ml) due to the lack of resistant isolates. QC range for H. Influenzae ATCC 49247 were established using multiple HTM agar and broth base lots, three disk lots for each drug, and a number of test replicates consistent with the National Committee for Clinical Laboratory Standards M23-T guideline.

Comparison of the E test and microdilution for detection of beta-lactam-resistant mutants that are stably derepressed for type I beta-lactamase

The activities of cefotaxime, ceftazidime, piperacillin, and aztreonam were compared in the E test and broth microdilution test against 30 gram-negative bacterial mutants derepressed for type I beta-lactamases. The results demonstrated complete agreement between 24-h MICs of 80 to 83% and essential agreement between 24-h MICs of 90 to 97%. When sufficient growth was present for the E test to be read at 6 h, the essential agreement between 6- and 24-h E-test MICs was 100% for ceftazidime, piperacillin, and aztreonam and 85% for cefotaxime.