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Bartonella quintana was isolated from 34 BACTEC nonradiometric aerobic resin blood cultures for 10 adults. Nine patients were initially diagnosed by routine acridine orange staining of routine cultures that had been incubated for 8 days. All subcultures grew on chocolate agar within 3 to 12 days (median, 6 days). The PLUS 26 high-volume aerobic resin medium, combined with acridine orange stain and subculture, is an effective system for detection and isolation of B. quintana from blood.

We report the demonstration of dimensional noncritical phase matching, a phase-matched interaction length exceeding 10 mm, and an internal conversion efficiency of 204%/W for second harmonic generation of 976 nm radiation in a periodically poled, annealed proton-exchanged LiNbO/sub 3/ waveguide. Using models for the linear and nonlinear optical properties of annealed proton-exchanged LiNbO/sub 3/ waveguides and the observed ferroelectric domain grating, the phase-matching wavelength was predicted to within several nm and the conversion efficiency to within /spl ap/20% of the measured values. Optimization of waveguide second harmonic generation devices is discussed. >

The crystalline structure of GaN epilayers on (0001) SiC substrates has been studied using x‐ray diffraction and transmission microscopy. The films were grown by metalorganic chemical vapor deposition, using AlN buffer layers. X‐ray diffraction measurements show negligible strain in the epilayer, and a long‐range variation in orientation. Transmission electron lattice images show that the AlN buffer layer consists of small crystallites. The nature of the buffer layer and its interfaces with the substrate and the GaN film is discussed. The defect structure of the GaN film away from the substrate consists mostly of threading dislocations with a density of ∼109 cm−2.

The crystalline structure near the substrate interface has been studied for AlGaN films grown on (0001) sapphire substrates by metalorganic chemical vapor deposition, using AlN buffer layers. Transmission electron lattice images show that the sapphire/AlN interface is coherent, with misfit dislocations separated by 2.0 nm, corresponding to relaxed bulk lattice parameters. The interface between the buffer layer and the AlGaN film is discussed. The defect structure of the epilayer near the substrate interface consists mostly of dislocations and stacking faults lying on basal planes.

Bacteremia with fever due to a novel subspecies of Bartonella vinsonii was found in a cattle rancher. The subspecies shared major characteristics of the genus Bartonella in terms of most biochemical features and cellular fatty acid profile, but it was distinguishable from other subspecies of B. vinsonii by good growth on heart infusion agar supplemented with X factor and by its pattern of enzymatic hydrolysis of peptide substrates. DNA relatedness studies verified that the isolate belonged to the genus Bartonella and that it was genotypically related to B. vinsonii. The highest level of relatedness was observed with recently characterized strains from naturally infected mice that were coinfected with Borrelia burgdorferi and Babesia microti. We propose the name Bartonella vinsonii subsp. arupensis subsp. nov. as the new subspecies to accommodate these human and murine isolates.

Low loss coupling and passive alignment of lasers to single mode fibers are key technologies for opto-electronic packaging. Single-mode fiber coupling of semiconductor lasers usually results in a significant insertion loss of several dB. This excess loss stems from the undesirable waveguide properties of laser diodes. A new design for 980 nm laser featuring low divergence (15°) and low ellipticity (1.5) is presented and shown to result in less than 1 dB coupling loss into a cleaved fiber. The active alignment cost of the singlemode fiber to the laser laser has a important impact on the the cost of photonic packages. We also report on a low-cost packaging technique based on passive alignment of a laser array to a Silica-on-Silicon waveguide array, with 36% coupling efficiency.

Extensive lifetesting is ongoing for single spatial mode 980 nm laser diodes suitable for pumping fiber amplifiers. Reliability estimates for commercially available lasers exceed the requirements for terrestrial deployment. Testing is currently being initiated on a new generation of devices that are expected to produce even better reliability at even higher powers that simplify amplifier design and reduce cost. New device designs, such as the master oscillator power amplifier (MOPA), have demonstrated radically higher single-mode fiber coupled powers and coupling efficiencies. Recently, coupling efficiencies into single-mode fiber of 68 % have been achieved with total fiber coupled power in excess of 800 mW. This represents more than an 8 fold increase over the maximum commercially available power of 90 mW, and should open new applications to fiber amplifiers. These fiber coupled powers are available at both 980 nm and 1017 nm.

We have demonstrated a 75 % coupling efficiency from a monolithically integrated master oscillator power amplifier (MOPA) diode laser source into a single-mode optical fiber. This was then used to pump a Pr3+-doped fiber amplifier. A net fiber gain of 19 dB was demonstrated and a 4 dB receiver enhancement was observed when the Pr3+-doped fiber was used as a preamplifier in a 2.5 Gbit NRZ transmission experiment.

Relatively penicillin-resistant pneumococci have caused 10% of invasive pneumococcal disease in central Oklahoma during the last decade, but almost no high-level penicillin or other antibiotic resistance has been described. This study evaluated antibiotic susceptibility and serotype distribution in invasive pneumococcal disease in the Oklahoma City metropolitan area (1990 population 848,000). A total of 144 cases of invasive infection was collected in 1 year (17 with meningitis, 120 with other bacteremic infections, and 7 with other invasive infections), for a rate of 16.9/100,000 (95% confidence interval [CI], 14.0-19.5). For the population agedor = 60, invasive pneumococcal disease rates were higher among nursing home residents (352/100,000) than among nonresidents (25.6/100,000; relative risk, 13.7; 95% CI, 7.7-24.7). Antibiotic-resistant organisms caused 19.4% of the cases: relative penicillin resistance, 7.6%; high-level penicillin resistance, 1.4% (2 cases), and 11% resistance to erythromycin, trimethoprim-sulfamethoxazole, or both, with 5% sharing both resistances plus a MIC of penicillin of 0.06 microgram/mL.

Two closely related species of Rochalimaea, Rochalimaea quintana and Rochalimaea henselae, are nutritionally fastidious but can be cultivated on bacteriologic media from the blood of patients with diverse clinical presentations. We report a case of culture-proven R. henselae bacteremia in a child with persistent fever. Serologic evidence of infection by R. henselae was ascertained by testing sera at two intervals for immunoglobulin G or immunoglobulin M antibodies by enzyme immunoassay and immunoblot. The case isolate and a collection of other strains (R. henselae, R. quintana, and related organisms) were used to test commercial identification systems for their comparative utility in the identification of Rochalimaea spp. on a practical basis. Of six systems designed for testing of either fastidious or anaerobic isolates of bacteria, the MicroScan Rapid Anaerobe Panel was the only system that distinguished R. henselae from R. quintana. Four of five others gave reactions that were unique within their data bases but did not distinguish Rochalimaea isolates at the species level.

Restriction endonuclease analysis of a polymerase chain reaction-amplified DNA fragment which included the spacer region between the genes coding for 16S and 23S rRNAs and a portion of the gene coding for 23S rRNA (spacer + 23S) was done on 10 previously characterized clinical isolates of Rochalimaea henselae, one clinical isolate of Rochalimaea quintana, and the type strains of R. henselae, R. quintana, Rochalimaea vinsonii, and Bartonella bacilliformis. Brucella abortus DNA was not amplified by the primer set used. The clinical isolates of Rochalimaea were obtained from blood or tissue from patients with and without preexisting disease. The amplicon from each strain was digested with five endonucleases (AluI, HaeIII, TaqI, HinfI, and MseI). AluI and HaeIII were useful in species differentiation and subtyping of R. henselae. R. henselae isolates showed six different restriction patterns with AluI and four patterns with HaeIII. TaqI, HinfI, and MseI were useful only in species differentiation. These observations indicate that PCR amplification of the spacer + 23S region of the ribosomal DNA of Rochalimaea spp., along with restriction endonuclease analysis, allows differentiation of Rochalimaea spp. from closely related genera, differentiation among the species within Rochalimaea, and differentiation of strains within R. henselae. The subtyping potential of this method may be useful for further clinical and epidemiologic studies of the spectrum of diseases caused by R. henselae.

Rochalimaea quintana and Rochalimaea henselae are closely related, fastidious, gram-negative rickettsiae. Thus far, the spectrum of human Rochalimaea sp. infections has not included endocarditis. We describe a 50-year-old human immunodeficiency virus-positive man who developed endocarditis caused by R. quintana. DNA relatedness studies, which compared our patient's blood culture isolate with known Rochalimaea species, identified the organism as R. quintana. Our report expands the spectrum of Rochalimaea sp. infections and identifies a new infectious cause of endocarditis.

The properties and low pressure organometallic vapor phase epitaxy of Gaxln1-xP/(AlGa)0.5ln0.5P quantum well (QW) laser diode heterostructures with Al0.5ln0.5P cladding layers, and having wavelength 614 660 nm), threshold current densities under 200 A/cm2 and efficiencies greater than 75% result from a biaxially-compressed GalnP QW active region. Although short wavelength laser performance is diminished by the poor electron confinement afforded by AlGalnP heterostructures, good 630 nm band performance, and extension into the 610 nm band, is achieved with strained, single QW active regions.

We report the immunocytochemical identification of Rochalimaea henselae, a newly recognized fastidious, Gram-negative, Warthin-Starry-positive organism, as the common pathogen in bacillary angiomatosis (BA), bacillary peliosis (BP) of the liver and spleen, and persistent fever with bacteremia in immunocompromised patients. Immunogenic proteins of the R. henselae strain isolated from the blood of a febrile immunocompromised patient with BP of the liver were used to produce primary immune serum in rabbits. Using immunocytochemical procedures, the polyclonal antiserum reacted strongly not only with the immunizing strain of the bacteria, but also with other blood isolates of R. henselae (five cases) from both immunocompromised and immunocompetent patients and with the organisms present in the tissue lesions of cutaneous BA (five cases) and BP of the liver (two cases) and spleen (one case). The blood isolates and BA and BP tissue samples were obtained from widely separated geographic areas. The antiserum was weakly cross-reactive with cultures of Rochalimaea quintana, an organism closely related to R. henselae, but this reactivity was eliminated by specific adsorption. The antiserum did not cross-react with the Warthin-Starry-positive organisms associated with cat scratch disease (Afipia felis), syphilis (Treponema pallidum), Lyme disease (Borrelia burgdorferi) or chronic active gastritis (Helicobacter pylori). Likewise, the antiserum did not identify organisms in eight cases of Kaposi's sarcoma, a disorder of immunocompromised patients that is clinically similar to BA. Further studies are needed to determine the prevalence of this newly recognized organism as well as its possible involvement in other angioproliferative diseases.

Recent studies have demonstrated that a newly described agent of persistent bacteremia, Rochalimaea henselae, and the agent of bacillary angiomatosis are both closely related to Rochalimaea quintana. Bacillary peliosis hepatis seemed likely to have the same etiologic agent as bacillary angiomatosis. We sought these pathologic changes in patients from whom R henselae was cultivated.For two patients whose histopathologic findings we reviewed, additional light and electron microscopy were performed. Their bacterial isolates were compared by electrophoretic patterns of outer membrane proteins, restriction endonuclease digestion patterns of DNA, and reaction with murine antiserum.A previously reported human immunodeficiency virus-infected man with persistent bacteremia due to R henselae was found to have bacillary peliosis hepatis. Rochalimaea henselae was also isolated from the spleen of a woman receiving immunosuppressive therapy after allogeneic renal transplantation. She had developed fever, liver and spleen nodules, and periaortic lymphadenopathy. Bacillary peliosis of her liver and spleen, as well as bacillary angiomatosis of liver, spleen, and a lymph node, were found. The bacterial isolates had comparable electrophoretic patterns of outer membrane proteins and of restriction endonuclease-digested DNA, which differed from the respective patterns of R quintana. Murine antisera raised to the first isolate reacted strongly with the second by means of immunoblot and immunofluorescence techniques, while reacting only weakly with R quintana.Rochalimaea henselae, recently recognized to cause persistent fever and bacteremia in immunocompetent and immunocompromised persons, also causes bacillary angiomatosis and parenchymal bacillary peliosis.

More than ever, new technology is having an impact on the tools of clinical microbiologists. The analysis of cellular fatty acids by gas-liquid chromatography (GLC) has become markedly more practical with the advent of the fused-silica capillary column, computer-controlled chromatography and data analysis, simplified sample preparation, and a commercially available GLC system dedicated to microbiological applications. Experience with applications in diagnostic microbiology ranges from substantial success in work with mycobacteria, legionellae, and nonfermentative gram-negative bacilli to minimal involvement with fungi and other nonbacterial agents. GLC is a good alternative to other means for the identification of mycobacteria or legionellae because it is rapid, specific, and independent of other specialized testing, e.g., DNA hybridization. Nonfermenters show features in their cellular fatty acid content that are useful in identifying species and, in some cases, subspecies. Less frequently encountered nonfermenters, including those belonging to unclassified groups, can ideally be characterized by GLC. Information is just beginning to materialize on the usefulness of cellular fatty acids for the identification of gram-positive bacteria and anaerobes, despite the traditional role of GLC in detecting metabolic products as an aid to identification of anaerobes. When species identification of coagulase-negative staphylococci is called for, GLC may offer an alternative to biochemical testing. Methods for direct analysis of clinical material have been developed, but in practical and economic terms they are not yet ready for use in the clinical laboratory. Direct analysis holds promise for detecting markers of infection due to an uncultivable agent or in clinical specimens that presently require cultures and prolonged incubation to yield an etiologic agent.

Recently, promising results have been obtained from a monolithically integrated master-oscillator power amplifier (M-MOPA) composed of a single-mode distributed Bragg-reflector (DBR) oscillator and linear chain of amplifiers and surface-emitting output couplers.1 The oscillator output is successively amplified in index-guided amplifiers and is coupled upwards from the wafer surface via detuned second-order DBR's. Coherent output power from this structure is nearly 0.5 W, in contrast to < 100 mW from coupled arrays of grating-surface-emitting oscillators.

The photoluminescence spectra were measured from 4 to 90 K for single-quantum-well structures of (Ga,In)As/(Al, In)As with well widths ${L}_{z}$=14.5 and 19.3 A\r{}. The optical transitions were observed from n=1 electrons in the conduction-band well to n=1 heavy holes (hh) and light holes (lh) in the valence-band well. Using the observed energy separation between hh and lh subbands, the well depth \ensuremath{\Delta}${E}_{v}$=120 meV for holes in the valence band and the corresponding well depth \ensuremath{\Delta}${E}_{c}$=740 meV for electrons in the conduction band were determined. This gives the relation of \ensuremath{\Delta}${E}_{c}$=0.85\ensuremath{\Delta}${E}_{g}$ which agrees with Dingle's rule for GaAs/(Al,Ga)As system.

The cellular fatty acid compositions were determined for 42 strains of Pseudomonas cepacia from five cystic fibrosis centers in North America. All isolates contained significant (20%) amounts of hexadecanoic (C16:0), and cis-9 hexadecenoic (C16:1 cis9) acids and an isomer of octadecenoic acid (C18:1). None had hydroxy acids containing fewer than 14 carbon atoms. The quantitative data from the fatty acid analysis were highly reproducible and provided a basis for numerical analysis. Five subgroups comprising all the strains were obtained by cluster analysis and further characterized by principal-component analysis. With minor exceptions, the predominant subgroup identified in each center was different from that identified in other centers and accounted for one-half of the isolates within each center. Cellular fatty acid composition is a useful adjunct to biochemical characterization for the identification of P. cepacia isolated from cystic fibrosis patients. Numerical analysis of the fatty acid data can separate P. cepacia into subgroups, which may provide useful epidemiologic information or a basis for further analysis by more complex techniques such as DNA probe analysis.

Indole spot tests using isolated, nonhemolytic colonies of Haemophilus species were positive for 90 of 151 (60%) respiratory isolates of Haemophilus influenzae, whereas 67 to 72 (93%) isolates of H. influenzae from cerebrospinal fluid and blood specimens were indole positive. Only 4 of 117 (3%) Haemophilus parainfluenzae isolates were positive for indole spot tests. Thus, indole-positive, nonhemolytic Haemophilus isolates in respiratory cultures can be presumptively identified as H. influenzae.

Phenolphthalein diphosphate was incorporated into a primary blood agar medium for use in performing quantitative urine cultures. Phosphatase-negative staphylococci, such as Staphylococcus saprophyticus, were differentiated from phosphatase-positive species, such as Staphylococcus epidermidis, by spot testing colonies on filter paper saturated with 1 N NaOH. Phosphatase-positive colonies turned pink within seconds, and phosphatase-negative colonies showed no color. None of 55 S. saprophyticus isolates showed production of phosphatase on this medium. Of 193 consecutive coagulase-negative staphylococci isolated from the urine of 190 adolescent female patients, 84% were phosphatase positive, non-S. saprophyticus species; 16% were phosphatase-negative and indicated S. saprophyticus (22), Staphylococcus haemolyticus (4), Staphylococcus simulans (2), Staphylococcus warneri (1), and Staphylococcus hominis (1). Phosphatase activity was variable in the other flora encountered in the urine cultures. Mixtures of phosphatase-positive and -negative organisms did not cause false-positive reactions.

During a 1-year period, the prevalence of thymidine-dependent (TD) Staphylococcus aureus in patients at two geographically distinct cystic fibrosis (CF) centers was determined. Of 200 CF patients who had their respiratory secretions cultured, 95 harbored S. aureus, and 20 (21%) had TD S. aureus as their predominant staphylococcal isolate. All 20 TD S. aureus-positive patients had received trimethoprim-sulfamethoxazole for an average of 30.9 months. It was also observed that TD S. aureus exhibited aberrant colony morphologies or did not grow on media commonly used in CF centers for S. aureus isolation, suggesting that this organism could be missed by routine culture methods. In contrast, all 20 isolates had typical staphylococcal morphology on mannitol salt agar after 48 h of incubation. Mannitol salt agar is recommended for primary isolation of TD S. aureus.

A selective and differential medium, OFPBL (oxidation-fermentation base supplemented with agar, lactose, and two antimicrobial agents), for the isolation of Pseudomonas cepacia from respiratory specimens of patients with cystic fibrosis was developed and tested. Among 725 specimens submitted from seven centers over a 4- to 6-month period, 58 (8%) yielded P. cepacia on OFPBL; only 19 of these were recovered on MacConkey or sheep blood agar (P less than 0.001). No isolate was recovered on MacConkey or sheep blood agar alone. Ranges of recovery rates among centers were 0 to 15% on OFPBL and 0 to 10% on MacConkey or sheep blood agar. Ninety percent of P. cepacia isolates were detected on OFPBL in less than or equal to 3 days. Other nonfermenters and yeasts isolated on OFPBL were distinguished from P. cepacia by failure to acidify the medium. The new medium was clearly superior to MacConkey and sheep blood agars for the isolation of P. cepacia from the respiratory secretions of patients with cystic fibrosis.

Cefoperazone agar dilution minimal inhibitory concentration (MIC) susceptibility results were compared with zones of inhibition produced by disk diffusion susceptibility testing. Disks containing 30, 50, 75, and 100 micrograms of cefoperazone were tested for purposes of regression line comparisons and error rate-bounded analysis. Results suggest that if the MIC equivalent of susceptibility is 32 micrograms/ml, either a 50-micrograms disk with zone sizes of susceptibility (S) greater than or equal to 15 mm and resistance (R) less than or equal to 12 mm or a 75-micrograms disk with zone sizes of S greater than or equal to 17 mm and R less than or equal to 14 mm may be appropriate. If the MIC equivalent of susceptibility is 64 micrograms/ml, this would dictate use of a 75-micrograms disk with zone sizes of S greater than or equal to 17 mm and R less than or equal to 12 mm. Disks containing either less than or equal to 30 or greater than or equal to 100 micrograms of cefoperazone did not adequately discriminate among susceptible and resistant bacterial strains at either the 32- or 64-micrograms/ml MIC equivalent.

Photoluminescence studies at 4 K on Ga0.47In0.53As/ Al0.48In0.52As single quantum wells exhibit emission ranging from 1.318 eV for a 15‐A well to 0.82 eV for thick wells. The emission energy of each single quantum well is compared to theoretical curves which are generated from a finite potential square well model. The closest agreement between the experimental curves and the theoretical curves occurs when the conduction band discontinuity is taken to be 70% of the band‐gap discontinuity or 0.52 eV.

High external power efficiencies of 36% are obtained from 5‐μm mesa isolated graded‐index separate‐confinement heterostructure single quantum well lasers grown by organometallic vapor phase epitaxy. Threshold currents of 21 mA are reported for a 5×96 μm cavity laser with differential quantum efficiencies of as high as 80% at 6 mW/facet. In addition, high facet power densities of 13 mW/μm are reported giving single ended output powers of 65 mW from 5‐μm uncoated facets. Even higher power densities of 20 mW/μm are observed for 1‐μm mesa stripe lasers before probe damage occurred.

GaInAs/AlInAs single quantum wells have been grown lattice matched to InP substrates by molecular beam epitaxy. The quantum well thicknesses ranged from 15 to more than 100 A. The low‐temperature photoluminescence exhibited a monotonically increasing spectral linewidth with decreasing well thickness. Of the several possible broadening mechanisms of the quantum well photoluminescence, two mechanisms were found to dominate: one mechanism for thin wells and one for thick wells. Quantum wells thicker than 50 A were found to have their low‐temperature photoluminescence spectra broadened primarily by a transfer of electrons from the AlInAs cladding layers into the GaInAs quantum well. Wells thinner than 50 A had their photoluminescence broadened mainly by interface roughness.

The photoluminescence linewidth (4 K) of Al0.48In0.52As was reduced to 15 meV and its dependence was determined to be a strong function of the substrate temperature and As4 overpressure. Raman spectroscopy correlates the luminescence broadening to the crystallinity of the AlInAs. The ratio of the allowed longitudinal optical phonon to forbidden transverse optical phonon Raman peak heights is 10:1.

A gain‐guided coupled‐stripe GaAs/GaAlAs diode laser array in an external cavity configuration consisting of a graded refractive index lens and a 25‐μm stripe apertured mirror was studied. Output power of almost 500 mW was obtained from the cavity under pulsed operation. A centered, single‐lobed far‐field radiation pattern which did not steer with the drive current was observed up to 4.1Ith. At 2Ith approximately 94% of the 102‐mW output power is contained in the 0.8° full width half‐maximum central lobe.

Ga0.47In0.53As/Al0.48In0.52As single quantum wells grown by molecular beam epitaxy have exhibited photoluminescence emission from 9668 A to the 1.55‐μm bulk emission at 4 K. The emission at 9668 A is 0.474 eV above the band gap of GaInAs. The single quantum well (SQW) is 15 A wide which is the narrowest SQW reported in any III‐V compound. The effect of varying the buffer layer of the SQW on the photoluminescence intensity of a 65‐A single quantum well is studied.

Streak camera observation of the time evolution of the near-field radiation pattern of flared Y-coupled diode laser arrays is reported. The arrays exhibit sustained self-pulsation at frequencies up to 4 GHz In CW operating conditions.

A new era of ever increasing optical output power, efficiency, and reliability has been achieved for GaAlAs quantum well lasers over the past several years. Beginning in 1982 quantum well laser diode arrays were demonstrated to be capable of achieving CW room temperature operation" Since that time higher output powers, higher efficiency, and greater reliability lasers have been demonstrated.

In vitro studies were performed to examine the potential usefulness of two new drugs, moxalactam and cefoperazone, for the treatment of infections caused by Streptococcus pneumoniae. 34 isolates of S. pneumoniae with differing susceptibilities to penicillin were examined by disk diffusion, agar and microbroth dilution methods. Isolates highly resistant to penicillin (MIC greater then 1 microgram/ml) were also resistant to moxalactam (MIC = 128 micrograms/ml) but were sensitive to cefoperazone (MIC = 2--4 micrograms/ml). All isolates relatively resistant to penicillin (MIC 0.25--0.5 micrograms/ml) were sensitive to cefoperazone (MIC 0.25--1 microgram/ml) and had moxalactam MICs of 4--16 micrograms/ml for 10/12 isolates. The disk diffusion test was unreliable for detecting strain relatively resistant to moxalactam. These studies showed that cefoperazone is more active than moxalactam in vitro against S. pneumoniae regardless of the penicillin susceptibility of these bacteria.

A five-center collaborative study was undertaken to determine the suitability of the Phadebact CSF test kit and the Phadebact group B Streptococcus reagent for routine use by clinical laboratories to detect antigens of common organisms causing bacterial meningitis. The kits employ staphylococcal protein A coagglutination to detect the antigens of Haemophilus influenzae types a, b, c, d, e, and f, Neisseria meningitidis groups A, B, C, Y, and W135, Streptococcus pneumoniae (83 serotypes), and group B Streptococcus. A total of 2,817 individual tests were performed on 577 cerebrospinal fluid specimens. The percent positive specimens detected by coagglutination was as follows: overall, 84%; H. influenzae, 97%; group B Streptococcus, 75%; S. pneumoniae, 71%; and N. meningitidis, 58%. Eighty-five of the specimens were also tested by counterimmunoelectrophoresis. Coagglutination was more sensitive than counterimmunoelectrophoresis because it detected 74% of the positive specimens, whereas counterimmunoelectrophoresis detected only 65%. No false-positive results were obtained with coagglutination. The Phadebact CSF test kit is recommended for routine use in screening cerebrospinal fluid samples for antigens of the common organisms causing bacterial meningitis along with the Gram stain and culture for delayed confirmation of the rapid results.

The inhibitory and bactericidal effects of sodium polyanetholesulfonate on Neisseria meningitidis were neutralized by blood lysis which occurs within the pediatric Isolator 1.5 Microbial tube (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.). Lysed blood was more effective than 2.5% gelatin in preventing the inhibitory effect. All but 1 of 16 N. meningitidis strains were killed by 0.06% sodium polyanetholesulfonate in the absence of lysed blood, whereas none were killed by 1.0% sodium polyanetholesulfonate when lysed blood was present. The possible clinical relevance of these results was reflected in the improved detection of meningococcemia in children when the Isolator 1.5 Microbial tube was compared with a conventional broth system.

Twenty-one cystic fibrosis patients under 3 years of age were enrolled in an open multicenter study to assess the feasibility of the study design and to compare selected pharmacologic features of cephalexin or dicloxacillin administered orally for 2 months. Patient tolerance and compliance were significantly less for dicloxacillin (p less than .01 and p less than .001, respectively). Superficial Candida infections were more common in the cephalexin group (p = 0.02), however increased stool frequency and nonspecific diaper rashes were more prevalent in patients receiving dicloxacillin (p less than .05). Staphylococcus aureus was isolated from respiratory secretions after 2 months from two dicloxacillin and no cephalexin patients. Areas under the curve and peak serum concentrations were higher for cephalexin (p less than .05 and p = .02), but antistaphylococcal activity in serum was higher for dicloxacillin (p less than .05) due to a lower mean MIC compared to cephalexin. Deep pharyngeal plus routine throat culture yielded more pathogens than either method alone. Express mail and central processing of respiratory specimens was efficient for most organisms, however there was some loss of Streptococcus pneumoniae and Haemophilus influenzae. Cephalexin was associated with better patient acceptance and compliance despite higher rates of superficial fungal infections as compared to dicloxacillin. Cephalexin, routine bacteriologic throat swabs processed locally or centrally, mail-in urine compliance assessment and a multicenter design are feasible components for a long-term prospective evaluation of antibiotic prophylaxis in patients with cystic fibrosis.

In vitro susceptibility to 17 antimicrobial agents was determined for Aeromonas caviae, A. hydrophila, and A. sobria isolated from feces of patients with diarrhea. The three Aeromonas species shared a similar susceptibility pattern, except to cephalothin. Of the oral antimicrobial agents, the quinolones, followed by chloramphenicol, were most active; trimethoprim-sulfamethoxazole and tetracycline had good but variable activity.

Listeria monocytogenes was examined for superoxide dismutase(SOD) activity. Two catalase-negative strains possessed at least twofold greater SOD activities than the catalase-positive L. monocytogenes strains examined. Growth conditions such as aeration and iron concentration influenced the specific activity of SOD obtained from cells cultured in defined media. L. monocytogenes SOD from crude extracts and after partial purification was analyzed by polyacrylamide gel electrophoresis. Iron was associated with the single band of SOD activity detected in the gels. SOD activity appeared to be primarily extracytoplasmic. Survival of organisms in a superoxide-generating medium was studied, with photoactivation of riboflavin used as the source of free radical formation. Virulent, catalase-positive L. monocytogenes strains were relatively resistant to killing in a pH 7 superoxide-containing medium. An intact-cell assay for SOD was developed, which used the superoxide-generating system and employed the superoxide-dependent oxidation of sulfite, added to the medium, and inhibition of this oxidation by SOD. Maximal SOD activites of intact cells were observed when 100 to 400 micrograms (dry weight) of viable Listeria cells per ml was added to the medium. A possible role for SOD in the pathogenesis of listeric infection is discussed.

Bacterial antigens representing 14 of the most common clinical isolates requiring serological confirmation for identification were prepared. These antigens were stable for periods in excess of 5 months, readily available, and sero-specific. Use of these antigens for quality control of bacterial typing antisera increased the accuracy, reduced the technician time, and obviated the delay which otherwise occurred while stock isolates were subcultured to provide a sero-specific control for this procedure.

Killing curves were employed to determine the in vitro bactericidal activity of cefoperazone against several aerobic bacterial species of clinical origin. Cefoperazone was bactericidal at concentrations equal to, or greater than, the minimal inhibitory concentration (MIC) but allowed regrowth of the organisms after four to six hours when tested in concentrations of one-fourth or one-half the MIC. Comparative studies with gentamicin, LY127935 (moxalactam), piperacillin, cefamandole, and cephalothin indicate that, in general, cefoperazone demonstrated similar killing activity as other beta-lactam compounds, with some strain differences noted. Gentamicin, as the representative aminoglycoside, demonstrated a greater rate of bactericidal activity than the beta-lactam compounds studied.

Pseudomonas gladioli was isolated from 11 patients with cystic fibrosis. It resembled Pseudomonas cepacia on the selective and differential medium OFPBL, producing yellow colonies after 48 to 72 h of incubation. Isolates were characterized biochemically, by DNA hybridization, and by cellular fatty acid analysis. A review of the clinical status of selected patients colonized by P. gladioli did not reveal any apparent association of this organism with infectious complications of cystic fibrosis. Thus, the clinical implications may differ depending on which of these two closely related species is reported by laboratories. Determination of the fatty acid profile of isolates by gas chromatography may be a useful adjunct to biochemical characterization as a means of identification. In contrast to P. cepacia, most isolates of P. gladioli contained 3-OH C10:0 fatty acid under the growth conditions used.

A counterimmunoelectrophoresis (CIE) technique which reacted positively with culture filtrates of Clostridium difficile was developed and compared with a cytotoxicity assay in human embryonic lung cell cultures. CIE, employing C. sordellii antitoxin, detected 17 of 17 C. difficile strains. Of those positive by CIE, 13 were cytotoxic in cell culture. Fourteen Clostridium species other than C. difficile, C. sordellii, and C. bifermentans were negative by CIE. C. sordellii and C. bifermentans gave positive CIE results but were not cytotoxic. Similar sensitivity of toxin detection was observed for both methods. Optimal conditions for performing CIE included use of 48-h chopped meat-glucose broth cultures as the antigen source, use of a 10x-concentrated U.S. Standard C. sordillii antitoxin, and electrophoresis for 1.5 h in 0.05 M tris(hydroxymethyl)aminomethane-barbital-sodium barbital, pH 8.8, at a constant current of 6 mA/slide. CIE appears to be a suitable alternative to the cytotoxicity assay and may serve as a means for presumptive identification of C. difficile.

Latex agglutination and coagglutination tests are commercially available as Bactogen and the Phadebact Haemophilus Test, respectively. We evaluated both for the detection of Haemophilus influenzae type b in cerebrospinal fluids. Both tests were positive in all of 51 culture-positive cases of meningitis caused by H. influenzae. Both were more sensitive than counterimmunoelectrophoresis. Antigen was also detected by Bactogen in seven of seven additional cerebrospinal fluid specimens (compared with four of seven by Phadebact) after 1 to 15 days of antimicrobial therapy. The cerebrospinal fluid of infants with meningitis owing to other common causative agents did not react with Bactogen or Phadebact. However, the cerebrospinal fluid of one patient with overwhelming infection owing to Proteus mirabilis reacted positively with Bactogen. Cost analysis revealed that Phadebact was less expensive to perform than Bactogen.

Phase-locked semiconductor diode laser arrays are capable of emitting light at high power in low divergence beams. Moreover, because of their small size and high electrical-to-optical conversion efficiency, these devices have many applications. The presentation begins with a review of semiconductor diode lasers and the principles of phased arrays. Various experiments relating to the lasers themselves and to their operation in external cavities are reviewed and the theory of their operation and conditions needed to favor lasing in a desired array mode (supermode) is discussed. The talk concludes with recent results concerning reliability.

Many applications of laser diode arrays, such as optical recording and point-to-point communications, require a stable, near diffraction limited beam. Recently phased array lasers have been demonstrated in which the emitters are locked in-phase but the far field pattern is multi-lobed due to the relative emitter widths and spacing1,2. In this paper we present data on "Y" coupled laser arrays which include flared waveguide at the facet to enlarge the near field spot size of the individual emitters. The near field "fill factor" is greater than 80% resulting in a predominantly single lobe radiation pattern. Such a laser is reported to emit a stable beam up to 150 mW cw.

Diode laser pumps for solid state lasers are reviewed with special emphasis on current and future capabilities.

Single quantum well laser diode arrays with emitting apertures of 200 um have operated up to 8 W cw. Monolithic multi-element arrays with emitting apertures of 1 cm are capable of cw operation up to 76 W cw. Devices fabricated using MOCVD epitaxial growth techniques and highly efficient single quantum well active region structures have exhibited high cw power and high efficiency. Catastrophic power limits of 8 W cw have been demonstrated by a 20 emitter multistripe laser diode with emitting aperture of 200 um. Similar structures consisting of 10 emitters in a 100 um aperture have operated to 6 W cw. (Fig. 1)

Gram-stained smears of specimens submitted for sputum cultures were compared with direct wet mounts examined by Nomarski interference contrast microscopy (NIM) for enumeration of squamous epithelial cells (EPC) and leukocytes (WBC). The results obtained by the two methods were comparable, but specimens were more rapidly screened and cell types were more readily differentiated by NIM. Specimens submitted for sputum culture over a 3-month period were examined for EPC and WBC by NIM. Twenty-two percent of the specimens had greater than 25 EPC/field or a predominance of EPC (class I), 30% had greater than 25 EPC and greater than 25 WBC/field (class II), and 48% had greater than 25 WBC/field or a predominance of WBC (class III). The clinical relevance of the culture results was determined by reviewing the records of patients whose specimens were included in the study. Class I specimens provided only 30% clinically relevant culture results. Specimens in class II provided useful culture results in 63% of the patients, and 96% of those in class III provided clinically relevant information. The results confirm the value of sputum screening and demonstrate that NIM provides a rapid, simple, and accurate method for sputum screening.