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Bed pushing during patient transfer is one of the most physically demanding and yet common tasks in the hospital setting. Powered bed movers have been increasingly introduced to hospitals to reduce physiological strains on the users. This study introduces and quantifies the manpower efficiency and health benefits of a novel robotic-assisted omni-directional hospital bed transporter (SESTO Bed Mover) in comparison with a conventional manual transport stretcher (Stryker Trauma Stretcher 1037) and a powered transport stretcher (HOSPIMEK HMPT 740), which has a fifth powered wheel providing power assistance only in the forward direction. A total of 14 subjects were recruited (7 porters and 7 students) and were tasked to complete a course within a controlled lab environment. It is concluded that the robotic bed mover is able to halve the required manpower to push hospital beds as compared to conventional bed pushing without any additional physiological strain, potentially improving efficiency by two-fold. Electromyography (EMG) patterns showed that users relied on the shoulder and back muscles in a fashion similar to conventional pushing, further confirming the intuitive drive of the robotic bed mover. Overall, the robotic bed mover shows reduced physical demands, less manpower required for patient transport and reduced back muscle activities, which strongly suggest health benefits for workers in the hospital., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

P3a and P3b event-related brain potentials (ERPs) were elicited with an auditory three-stimulus (target, distracter, and standard) discrimination task in which subjects responded only to the target. Distracter stimuli consisted of white noise or novel sounds with stimulus characteristics perceptually matched. Target/standard discrimination difficulty was manipulated by varying target/standard pitch differences to produce relatively easy, medium, and hard tasks. Error rate and response time increased with increases in task difficulty. P3a was larger for the white noise compared to novel sounds, maximum over the central/parietal recording sites, and did not differ in size across difficulty levels. P3b was unaffected by distracter type, decreased as task difficulty increased, and maximum over the parietal recording sites. The findings indicate that P3a from white noise is robust and should be useful for applied studies as it removes stimulus novelty variability. Theoretical perspectives are discussed., (Copyright © 2012 Elsevier B.V. All rights reserved.)

We evaluated the use of peptone-yeast extract (PY) medium, different strains of Hartmannella vermiformis, and gentamicin in a coculture system to improve the discrimination of virulent and avirulent strains of Legionella pneumophila. H. vermiformis ATCC 50256 was unique among four strains of H. vermiformis, in that it multiplied equally well in Medium 1034 and PY medium (Medium 1034 without fetal calf serum, folic acid, hemin, and yeast nucleic acid and with a 50% reduction of peptone). However, both a virulent strain of L. pneumophila and its avirulent derivative strain multiplied in cocultures when PY medium was used. The multiplication of this avirulent strain was greatly reduced by incorporating gentamicin (1 (mu)g/ml) into the cocultivation system. Five virulent-avirulent sets of L. pneumophila strains were then tested for multiplication in cocultures with H. vermiformis ATCC 50256 and the gentamicin-containing PY medium. Only the virulent strains multiplied. The modified cocultivation system can discriminate between virulent and avirulent strains of L. pneumophila.

Hartmannella vermiformis, a common amoebal inhabitant of potable-water systems, supports intracellular multiplication of Legionella pneumophila and is probably important in the transportation and amplification of legionellae within these systems. To provide a practical guide for decontamination of potable-water systems, we assessed the chlorine and heat resistance of H. vermiformis. H. vermiformis cysts and trophozoites were treated independently with chlorine at concentrations of 2.0 to 10.0 ppm for 30 min and then cocultured with L. pneumophila. Both cysts and trophozoites were sensitive to concentrations between 2.0 and 4.0 ppm and above (trophozoites somewhat more so than cysts), and 10.0 ppm was lethal to both forms. Hartmannellae treated with chlorine up to a concentration of 4.0 ppm supported the growth of legionellae. To determine whether heat would be an effective addendum to chlorine treatment of amoebae, hartmannellae were subjected to temperatures of 55 and 60 degrees C for 30 min and alternatively to 50 degrees C followed by treatment with chlorine at a concentration of 2 ppm. Fewer than 0.05% of the amoebae survived treatment at 55 degrees C, and there were no survivors at 60 degrees C. Pretreatment at 50 degrees C appeared to make hartmannella cysts more susceptible to chlorine but did not further reduce the concentration of trophozoites.

A model was developed to study the multiplication of various Legionella spp. in tap water containing Hartmannella vermiformis. Tap water cultures prepared with the following components were suitable for the multiplication studies: Legionella spp., 10(3) CFU/ml; H. vermiformis, 10(4.4) cysts per ml; and killed Pseudomonas paucimobilis, 10(9) cells per ml. Cocultures were incubated at 37 degrees C for at least 1 week. The following legionellae multiplied in tap water cocultures in each replicate experiment: L. bozemanii (WIGA strain), L. dumoffii (NY-23 and TX-KL strains), L. micdadei (two environmental strains), and L. pneumophila (six environmental strains and one clinical isolate). Growth yield values for these strains were 0.6 to 3.5 log CFU/ml. Legionellae which did not multiply in replicate cocultures included L. anisa (one strain), L. bozemanii (MI-15 strain), L. micdadei (a clinical isolate), L. longbeachae, (one strain), and L. pneumophila (Philadelphia 1 strain). L. gormanii and an environmental isolate of L. pneumophila multiplied in only one of three experiments. None of the legionellae multiplied in tap water containing only killed P. paucimobilis. The mean growth yield (+/- standard deviation) of H. vermiformis in the cocultures was 1.2 +/- 0.1 log units/ml. H. vermiformis supports multiplication of only particular strains of legionellae, some of which are from diverse origins.

Two children with legionellosis complicating a relapse of acute lymphoblastic leukemia are reported. A 5-year-old boy with pneumonia had Legionella pneumophila cultured from a tracheal aspirate following a rapid deterioration in his respiratory status and intubation. This child had severe and irreversible granulocytopenia and died in spite of therapy with erythromycin and rifampin added five days later. Combination antimicrobial therapy is suggested for immunosuppressed children with legionellosis if resolution of neutropenia is not readily anticipated. Culture of Legionella sp from respiratory tract secretions or sputum, as reported for the first time in the pediatric literature, should be attempted in all children in whom this infection is suspected. A 13-year-old boy with pneumonia recovered in spite of therapy with antimicrobial agents not proven to be effective against the legionellae. Clinical improvement coincided with increase in absolute granulocyte count. A retrospective diagnosis was made when seroconversion to Legionella micdadei (less than 1:16 to 1:1,024) was determined during a survey of unselected sera from 255 hospitalized children. This is the first documented case of Pittsburgh pneumonia described in a child.

During a 3-month period, 1,062 mother-infant pairs were studied for infections following internal fetal monitoring during labor. Six infants (0.56%) developed septic scalp dermatitis at the site of the spiral electrode application. Factors associated with septic scalp dermatitis included the number of vaginal examinations, the use of an intrauterine pressure catheter or of more than one spiral electrode, and fetal scalp blood sampling. Maternal diabetes and endomyometritis were also associated with an increased risk of scalp infection. The duration of spiral electrode use and duration of ruptured membranes were not significant risk factors. Endomyometritis was documented in 41 mothers, an overall incidence of 3.9%. In women whose babies were delivered by cesarean section, the incidence of endomyometritis was 28/117 (23.9%). Using multivariate analysis by logistic regression, endomyometritis was associated with the number of vaginal examinations during labor but not with the duration of internal monitoring, duration of labor, or duration of ruptured membranes.

An abbreviated three-dimensional checkerboard titration method was devised to determine whether synergistic interaction of three antimicrobial agents could be found against multidrug-resistant bacteria. Pseudomonas maltophilia was used as the test organism because of its resistance to most commercially available antimicrobial agents, including those active against Pseudomonas aeruginosa. Three-dimensional isobolograms with concave surfaces were formed when synergy occurred. Triple combinations of gentamicin-carbenicillin-rifampin (mean fractional inhibitory concentration index, 0.32) and trimethoprim/sulfamethoxazole-carbenicillin-rifampin (mean fractional inhibitory concentration index, 0.18) were consistently synergistic against 14 clinical isolates of P. maltophilia.

Eight immunosuppressed patients had pneumonia due to Pittsburgh Pneumonia Agent (PPA), a gram-negative, weakly acid-fast bacterium cultivatable only in embryonated eggs and guinea pigs and distinct from Legionella pneumophila. The diagnosis was established by isolation of the agent from lung or visualization of the organism in lung tissue. The clinical presentations, radiographic abnormalities and pathology were not specific. The most consistent feature associated with the disease was the recent institution of daily high-dose corticosteriod therapy in all patients. Five of the eight patients died despite broad-spectrum antibiotic and antituberculous therapy. Anti-microbial activity against PPA was demonstrated for sulfamethoxazole combined with trimethoprim, for rifampin and for erythromycin with an egg-protection assay. Serologic studies with an indirect fluorescent-antibody technic suggested that seroconversion or high titers may be a sensitive test for PPA disease. PPA appears to be a newly recognized cause of life-threatening bacterial pneumonia in immunosupressed patients.

An immunocompromised patient developed pneumonia in which both Legionella micdadei and L. pneumophila, serogroup 6, were isolated from transtracheal aspirates in the absence of any other bacteria. Unusual features included the development of disseminated intravascular coagulation and multiple pulmonary abscesses during treatment with erythromycin, and relapse of the legionellosis after extended therapy with both erythromycin and rifampin, which was heralded by septic shock. Because simultaneous infection with two distinct species of Legionella occurs, concurrent increases in antibody titer to more than one Legionella may, in some instances, reflect multiple infection rather than cross-reacting antibody.

Correlation between in vitro and in vivo test results for synergy between carboxypenicillins and aminoglycosides against Pseudomonas aeruginosa is poor. Although the divalent cation content of culture media is known to affect aminoglycoside susceptibility testing for P. aeruginosa, this effect of divalent cations has not been examined for synergy testing of carboxypenicillin-aminoglycoside interaction against P. aeruginosa. The minimal inhibitory concentrations (MICs) of tobramycin and ticarcillin and the interaction of these drugs in combination were studied by a microtitration method for 36 strains of P. aeruginosa in Mueller-Hinton broth with varying supplements of calcium, magnesium, and zinc. The supplementation of Mueller-Hinton broth to 50 or 100 mg of calcium per liter had a significant effect in increasing the tobramycin MIC (P less than 0.01), as well as decreasing the degree of synergy between ticarcillin and tobramycin (P less than 0.01). Supplementation to 20 mg of magnesium per liter, 1.0 mg of zinc per liter, or both did not significantly affect tobramycin MIC or the interaction of tobramycin and ticarcillin. Supplementation to 50 or 100 mg of calcium per liter rendered any additional effect of magnesium and zinc on aminoglycoside MIC and aminoglycoside-carboxypenicillin interaction negligible. If these results for ticarcillin and tobramycin are confirmed for other carboxypenicillins and aminoglycosides, then the Mueller-Hinton broth used for P. aeruginosa aminoglycoside susceptibility and synergy testing may need to be supplemented only with calcium at a concentration of 50 mg/liter.

Photosynthetic cyanobacteria, heterotrophic bacteria, free-living amoebae, and ciliated protozoa may support growth of Legionella pneumophila. Studies were done with two tap water cultures (WS1 and WS2) containing L. pneumophila and associated microbiota to characterize growth-supporting activity and assess the relative importance of the microbiota in supporting multiplication of L. pneumophila. The water cultures were incubated in the dark at 35 degrees C. The growth-supporting factor(s) was separated from each culture by filtration through 1-micron-pore-size membrane filters. The retentate was then suspended in sterile tap water. Multiplication of L. pneumophila occurred when both the retentate suspension and the filtrate from either culture were inoculated into sterile tap water. L. pneumophila did not multiply in tap water inoculated with only the filtrate, even though filtration did not reduce the concentration of L. pneumophila or heterotrophic bacteria in either culture. Growth-supporting activity of the retentate suspension from WS1 was inactivated at 60 degrees C but unaffected at 0, 25, and 45 degrees C after 30-min incubations. Filtration experiments indicated that the growth-supporting factor(s) in WS1 was 2 to 5 micron in diameter. Ciliated protozoa were not detected in either culture. Hartmannellid amoebae were conclusively demonstrated in WS2 but not in WS1. L. pneumophila multiplied in tap water inoculated with the amoebae (10(3)/ml) and the 1-micron filtrate of WS2. No multiplication occurred in tap water inoculated with the filtrate only. Growth-supporting activity for L. pneumophila may be present in plumbing systems; hartmannellid amoebae appear to be important determinants of multiplication of L. pneumophila in some tap water cultures.

A study was conducted to compare the susceptibility of legionellae and coliforms to disinfection by chlorine. The chlorine residuals used were similar to concentrations that might be found in the distribution systems of large public potable water supplies. The effects of various chlorine concentrations, temperatures, and pH levels were considered. A number of different Legionella strains, both environmental and clinical, were tested. The results indicate that legionellae are much more resistant to chlorine than are coliform bacteria. At 21 degrees C, pH 7.6, and 0.1 mg of free chlorine residual per liter, a 99% kill of L. pneumophila was achieved within 40 min, compared with less than 1 min for Escherichia coli. The observed resistance is enhanced as conditions for disinfection become less optimal. The required contact time for the removal of L. pneumophilia was twice as long at 4 degrees C than it was at 21 degrees C. These data suggest that legionellae can survive low levels of chlorine for relatively long periods of time.

Samples obtained from plumbing systems of hospitals, nonhospital institutions and homes were cultured for Legionella spp. by plating the samples directly on a selective medium. Swab samples were taken from the inner surfaces of faucet assemblies (aerators, spouts, and valve seats), showerheads, and shower pipes. Water and sediment were collected from the bottom of hot-water tanks. Legionella pneumophila serogroups 1, 5, and 6 were recovered from plumbing fixtures of the hospitals and nonhospital institutions and one of five homes. The legionellae (7 to 13,850 colony-forming units per ml) were also present in water and sediment from hot-water tanks maintained at 30 to 54 degrees C, but not in those maintained at 71 and 77 degrees C. Legionella micdadei was isolated from one tank. Thus legionellae are present in hot-water tanks which are maintained at warm temperatures or whose design results in warm temperatures at the bottom of the tanks. We hypothesize that hot-water tanks are a breeding site and a major source of L. pneumophila for the contamination of plumbing systems. The existence of these bacteria in the plumbing systems and tanks was not necessarily associated with disease. The extent of the hazard of this contamination needs to be delineated.

Legionella pneumophila serogroup 1 was observed to satellite around colonies of Flavobacterium breve on an L-cysteine-deficient medium which did not support growth of legionellae. Both isolates were recovered from the hot water tanks of hospitals. Ferric PPi stimulated satellite growth between 0.01 and 0.1%.

Twenty acutely ill patients requiring prolonged orotracheal intubation were studied to determine the source and progression of gram-negative bacilli colonizing the trachea. Organisms recovered from daily tracheal, hypopharyngeal, and rectal cultures were typed and speciated to identify identical strains at the three sites. All patients acquired gram-negative bacilli in the trachea by day 3 after intubation. Thirty organisms that were not recovered from the tracheal aspirate immediately following intubation were isolated for at least two days some time thereafter. Nine of the 30 colonizing bacteria were Enterobacteriaceae, and all were found in another culture site, usually the hypopharynx, before isolation from the trachea. In contrast, only four of the 21 non-Enterobacteriaceae that colonized the trachea were recovered previously from either the hypopharynx or rectum, a finding which represents a significant difference (P = 0.0002). Quantitation of isolates from the hypopharynx was of no value in predicting subsequent acquisition in the trachea, and the numbers of bacteria recovered from the first positive tracheal specimen were not predictive of subsequent persistence in the trachea.

High-titer preparations of Klebsiella bacteriocins (klebocins) were obtained by using mitomycin to induce standard strains of Klebsiella. Of 296 clinical isolates of Klebsiella, 67% could be typed on the basis of their sensitivity to klebocins. The method proposed in this paper affords a standard basis for the further development of klebocin typing as a suitable procedure for hospital laboratories concerned with epidemiological investigations of hospital-associated infections. Evidence is also provided to show that high-titered klebocin typing can be used in conjunction with biochemical typing to provide a sensitive epidemiological marker for Klebsiella.

Two hundred and ninety-four isolates of Escherichia coli, including 105 from blood cultures, 94 from stools of hospital inpatients, and 96 from rectal cultures of healthy young adults, were biotyped by using the API-20E system and tested for the presence of K1 antigen. The overall frequency of K1 strains was 14.2% and was similar among the three sources. Forty-eight biotypes were observed, but two-thirds of all isolates, including two-thirds of the K1 strains, belonged to only five biotypes. Among the five commonest biotypes, the distribution of K1 strains was nonrandom, since 23 of the 27 K1 strains belonged to only two biotypes. Analysis of the O and H antigens of K1 strains indicated that this correlation of biotype with K1 antigen was due to a restricted number of serovars ("clones") that were repeatedly isolated from the population studied. These serovas included O18:K1:H7, O1:121:H6 and O16:K1:H6. Although a statistically significant correlation between biotype and K1 antigen was observed, the correlation was not sufficiently great to alow biotyping to be of significant predictive value as a marker for the K1 antigen.

MICs of ticarcillin, tobramycin, and rifampin alone and in combination were determined by a three-dimensional checkerboard method for 33 isolates of Pseudomonas aeruginosa. Twenty-nine of 33 isolates were affected synergistically (FIC index less than 1.0) by the combination of ticarcillin-tobramycin, including 13 of the 16 isolates resistant to ticarcillin and/or tobramycin alone. However, despite fulfilling the criteria for synergy, the MIC of the ticarcillin and/or tobramycin when in combination still exceeded attainable serum concentrations for 12 of the 13 resistant isolates. When rifampin was added to ticarcillin-tobramycin, a synergistic interaction was observed for all 33 isolates. Furthermore, of the 16 isolates resistant to ticarcillin and/or tobramycin, eight were inhibited by attainable concentrations of all three antibiotics in combination. If these results can be confirmed in the clinical situation, application of the three-drug combination of ticarcillin-tobramycin-rifampin might improve survival in selected patients with serious P. aeruginosa infections.

Glycine, at a final concentration of 0.3%, has been shown to be an excellent selective agent for the isolation of Legionellaceae. Stock cultures of Legionella pneumophila were not inhibited on buffered charcoal-yeast extract agar containing the amino acid. Among the other Legionellaceae tested, only one of two strains of L. dumoffii and two of six strains of L. micdadei were appreciably inhibited. This medium permitted the isolation of L. pneumophila from environmental specimens with marked inhibition of many non-Legionellaceae bacteria. The selectivity of the medium was subsequently improved by the incorporation of vancomycin (5 microgram/ml) and polymyxin B (100 U/ml). This selective medium, glycine-vancomycin-polymyxin B agar, should facilitate the recovery of Legionellaceae from environmental sources.

Previous studies have shown that bacteria maintained in a low-nutrient "natural" environment such as swimming pool water are much more resistant to disinfection by various chemical agents than strains maintained on rich media. In the present study a comparison was made of the chlorine (Cl2) susceptibility of hot-water tank isolates of Legionella pneumophila maintained in tap water and strains passaged on either nonselective buffered charcoal-yeast extract or selective differential glycine-vancomycin-polymyxin agar medium. Our earlier work has shown that environmental and clinical isolates of L. pneumophila maintained on agar medium are much more resistant to Cl2 than coliforms are. Under the present experimental conditions (21 degrees C, pH 7.6 to 8.0, and 0.25 mg of free residual Cl2 per liter, we found the tap water-maintained L. pneumophila strains to be even more resistant than the agar-passaged isolates. Under these conditions, 99% kill of tap water-maintained strains of L. pneumophila was usually achieved within 60 to 90 min compared with 10 min for agar-passaged strains. Samples from plumbing fixtures in a hospital yielded legionellae which were "super"-chlorine resistant when assayed under natural conditions. After one agar passage their resistance dropped to levels of comparable strains which had not been previously exposed to additional chlorination. These studies more closely approximate natural conditions than our previous work and show that tap water-maintained L. pneumophila is even more resistant to Cl2 than its already resistant agar medium-passaged counterpart.

A simplified, concise scheme was developed for the identification of nonfermentative, gram-negative bacteria which have most frequently been reported in the literature as definite or possible agents of human disease. These organisms included apyocyanogenic Pseudomonas aeruginosa, P. fluorescens, P. putida, P. stutzeri, P. maltophilia, P. putrefaciens, P. cepacia, P. alcaligenes, FLAVOBACTERIUM SPECIES, Bordetella bronchiseptica, Acinetobacter anitratum (Herellea vaginicola), A. Iwoffi (Mima polymorpha), Moraxella species, Alcaligenes odorans and Alcaligenes species. The tests used for identification included production of cytochrome oxidase, amylase, deoxyribonuclease, gelatinase, urease and Beta-galactosidase; motility; oxidation of one per cent glucose and ten per cent lactose; fluorescence; indole, hydrogen sulfide and nitrogen gas production; denitrification of nitrites; growth at 42C; penicillin sensitivity and production of an aromatic odor and greenish discoloration on blood agar. Using this scheme, 85 per cent of 243 isolates (unknowns and reference strains) were identified to genus and species. Of the 15 per cent remaining, 11 per cent were identified as alkaline organisms and four per cent were unidentifiable.

The ability of topical antiseptics to penetrate eschar of burn patients was determined by the agar diffusion technique. Gentamicin sulfate, mafenide acetate, nitrofurazone, povidone-iodine, silver nitrate, and silver sulfadiazine were tested against clinical isolates of Candida albicans, Staphylococcus, Streptococcus, and gram-negative bacilli including Pseudomonas aeruginosa. In practically all instances, the diameters of the zones of inhibition observed using eschar were comparable to those obtained with filter-paper discs. This finding showed that the antimicrobial agents could penetrate eschar and retain their effectiveness after penetration.

Earlier field and laboratory studies have shown that Legionella species survive and multiply in the pH range 5.5 to 9.2. Additionally, the technical feasibility of operating cooling towers at elevated alkalinities and pH has previously been documented by published guidelines. The guidelines indicate that these conditions facilitate corrosion control and favor chlorine persistence which enhances the effectiveness of continuous chlorination in biofouling control. This information suggests that control of Legionella species in cooling towers can be accomplished by operating the towers under alkaline conditions. To test this possibility, we collected water samples over a period of months from a hospital cooling tower. The samples were analyzed for a variety of chemical parameters. Subsamples were pasteurized and inoculated with non-agar-passaged Legionella pneumophila which had been maintained in tap water. Correlation of subsequent Legionella growth with corresponding pH and alkalinity values revealed statistically significant inverse associations. These data support the hypothesis that operating cooling towers outside of the optimal conditions for Legionella growth (e.g., at elevated alkalinities and a pH greater than 9) may be a useful approach to controlling growth in this habitat.

During a 7-day period, a variety of bacteria, including opportunistic ones, were recovered from 23 rolls of adhesive tape being used in a 16-bed intensive care unit. All rolls of tape were sterile when received from the manufacturer. Mixed flora was recovered from a total of 15 rolls, whereas eight rolls yielded pure cultures. Organisms recovered included Staphylococcus aureus, Pseudomonas aeruginosa, and various species of Enterobacteriaceae. Although no illness or infection arising directly from contaminated adhesive tape has been documented, we feel that a potential source of infection has been identified. Most important is the fact that such tape may contaminate the hands of personnel who handle it. Also, the adhesive tape may directly contaminate a patient since it is widely used to secure artificial airways and various drainage tubes which results in the tape coming into close contact with the mucous membranes lining the patient's respiratory and urogenital tracts.

A naturally occurring suspension of Legionella pneumophila and associated microbiota contained three unidentified non-Legionellaceae bacteria which supported satellite growth of a subculture of L. pneumophila on an L-cysteine-deficient medium and another bacterium which did not support growth of the subculture. Washed suspensions containing 10(3), 10(5), 10(7), or 10(8) CFU of a mixture of isolates of these non-Legionellaceae bacteria failed to support the multiplication of an isolate of agar-grown L. pneumophila which had been washed and seeded into the suspensions. The suspensions which contained 10(3), 10(5), or 10(7) CFU of the non-Legionellaceae bacteria per ml appeared to enhance survival or cryptic growth of agar-grown L. pneumophila. A decline of 1.3 log CFU of L. pneumophila per ml occurred within the first week of incubation in the sample which contained 10(8) CFU of the non-Legionellaceae bacteria per ml. In contrast to these results, naturally occurring L. pneumophila multiplied in the presence of associated microbiota. The necessity to subculture L. pneumophila and the non-Legionellaceae bacteria on artificial medium to obtain pure cultures may have affected the multiplication of L. pneumophila in tap water. Alternatively, other microorganisms may be present in the naturally occurring suspension which support the growth of this bacterium.

Klebsiella, Enterobacter, and Serratia were recovered frequently in high counts from vegetable salads. Pseudomonas aeruginosa, although isolated frequently, was in lower counts.

A water culture containing naturally occurring Legionella pneumophila and associated microbiota was maintained in the laboratory by serially transferring the culture in tap water which had been sterilized by membrane filtration. Successful maintenance of the water culture depended upon transferring the culture when the growth of L. pneumophila was in the late-exponential to early-stationary phase. The water culture was used as a source of naturally occurring bacteria to determine some of the parameters which affect the multiplication of L. pneumophila in tap water. Naturally occurring L. pneumophila multiplied at a temperature between 25 and 37 degrees C, at pH levels of 5.5 to 9.2, and at concentrations of dissolved oxygen of 6.0 to 6.7 mg/liter. Multiplication did not occur in tap water which contained less than 2.2 mg of dissolved oxygen per liter. An association was observed between the multiplication of L. pneumophila and the non-Legionellaceae bacteria which were also present in the water culture. The method of preserving naturally occurring L. pneumophila and associated microbiota may facilitate studies on the symbiosis of L. pneumophila with other microorganisms.

An immunofluorescent slide method incorporating 0.1% (wt/vol) Evans blue as a counterstain was developed and compared with a recently described tube method. Seventy-one urine specimens were tested concurrently by both methods. Results of the two methods agreed in 70 specimens and disagreed in only 1. We found the slide method to be less costly and time consuming than the tube method.

Naturally occurring Legionella pneumophila, an environmental isolate which had not been grown on artificial medium, was tested for the ability to multiply in tap water. A showerhead containing L. pneumophila and non-Legionellaceae bacteria was immersed in nonsterile tap water supplying this fixture. Also L. pneumophila and non-Legionellaceae bacteria were sedimented from tap water from a surgical intensive care unit. This bacterial suspension was inoculated into tap water from our laboratory. The legionellae in both suspensions multiplied in the tap water at 32, 37, and 42 degrees C. The non-Legionellaceae bacteria multiplied at 25, 32, and 37 degrees C. A water sample which was collected from the bottom of a hot water tank was found to contain L. pneumophila and non-Legionellaceae bacteria. These legionellae also multiplied when the water sample was incubated at 37 degrees C. These results indicate that L. pneumophila may multiply in warm water environments such as hot water plumbing fixtures, hot water tanks, and cooling towers.

In an analysis of legionellosis at Presbyterian-University Hospital in Pittsburgh during the 28 months after the original outbreak of pneumonia caused by Legionella micdadei , 101 consecutive renal-allograft recipients were studied. The prevalence of elevated titers of antibody to Legionella pneumophila or L. micdadei among the patients at the time of transplantation (21.6%) was not significantly different from that among kidney donors (13.4%; P greater than .25). Seroconversion occurred in 21 (23.6%) of 89 recipients during the six months after transplantation. Seven recipients who seroconverted were diagnosed as having legionella pneumonia, eight had fever and pneumonitis attributed to other causes but compatible (on clinical grounds) with legionella infection, and six had no clinical evidence of infectious pneumonia. The interval from transplantation to onset of pneumonia was shorter for recipients with evidence of L. micdadei pneumonia than for patients with L. pneumophila pneumonia (P = .006); this finding suggested that the former disease occurred when the recipients were most immunocompromised. The original outbreak of L. micdadei pneumonia was found to have subsided nine months after the last formally recognized case, but infections with L. pneumophila continued to occur thereafter.

The incidence of infections due to Serratia marcescens increased steadily at the Veterans Administration Hospital in Pittsburgh, Pennsylvania from 1970 to mid 1975 followed by a decline extending into 1977. One hundred eighty-four Serratia marcescens isolates were collected from 123 patients over a 4-month period in 1975 and were characterized by stereotype and antibiotic sensitivity. Three-fourths of the isolates were clinically significant. Among 24 stereotypes O-:H2 predominated in the urinary tract and O-H12 in respiratory secretions. Clusters of serotypes were on occasion identified in the GU Surgery Ward and the Intensive Care Unit. Uninary isolates showed remarkable resistance to antibiotics; only two thirds were susceptible to amikacin, the most effective agent in vitro. The patients from whom Serratia was isolated were older than the general hospital population (60 vs. 53.6 years of age), were hospitalized longer than the age-corrected controls (62 vs. 34.5 days) and two-thirds of thirds of them acquired the infection in the hospital. Uninary catheterization and prior antibiotic therapy were significant risk factors for urinary infections, and prior surgery contributed to recovery of Serratia from the respiratory tract. Serotype and antibiotype differences between isolates from the urinary and those from the respiratory tract suggest that strains evolved a site specificity.

A medium, Bacteroides fragilis bile-esculin (BBE) agar, was designed for the selection and, presumptive identification of the B. fragilis group. BBE agar contains bile, esculin, ferric ammonium citrate, hemin, and gentamicin in a Trypticase soy agar base. Growth in the presence of 20% bile and esculin hydrolysis, detected by blackening of the medium, provide presumptive evidence for the identification of the B. fragilis group. In addition to stimulating the growth of many strains of the B. fragilis group, hemin provides the option of testing isolates for catalase production. Gentamicin and bile prevent the growth of most organisms other than the esculin-positive bacteroides that can tolerate bile. Of 160 clinical isolates of the B. fragilis group tested on BBE agar, 159 grew well on the medium and 157 blackened it. Other anaerobes, Enterobacteriaceae, and enterococci either failed to grow on BBE agar or did not produce the characteristic morphology and blackening associated with isolates of the B. fragilis group. In a clinical laboratory trial, 687 specimens from patients were inoculated onto BBE agar plates. The B. fragilis group was recovered from 81 (11.8%) of these specimens in 24 to 48 h. Use of BBE agar in the clinical laboratory enables earlier recovery and identification of this important pathogen.

Pseudomonas maltophilia is resistant to most of the commonly used antimicrobial agents including those active against Pseudomonas aeruginosa. The susceptibility of 14 clinical isolates of P. Maltophilia to 18 antimicrobial agents was determined by broth dilution testing. All organisms were susceptible to trimethoprim-sulfamethoxazole (TMP-SMZ), minocycline, and LY127935. A total of 87 and 79% of the organisms were susceptible in vitro to colistin and chloramphenicol, respectively. With the exception of sisomicin, the organisms were resistant to the aminoglycosides. Of 21 combinations of antimicrobials examined for synergy, only the combination of TMP-SMZ with carbenicillin was consistently (86%) synergistic in vitro. Supplementation of the testing media with calcium and magnesium increased the minimal inhibitory concentrations for the aminoglycosides, the penicillins, and TMP-SMZ against P. maltophilia.

Thirty-nine patients receiving chemotherapy for acute leukemia had weekly determinations of Candida precipitins by use of counterimmunoelectrophoresis. The only two patients who had proven disseminated candidiasis both had diagnostic (greater than or equal to 1/8) titers. However, most patients with "possible" disseminated candidiasis did not have diagnostic titers. The test's specificity was high (90%), and only one of five patients infected with other fungi had diagnostic titers. However, because there were so few "true positives" in this small series, the relatively small number of "false positives" resulted in a low predictive value for this test. Based on a review of the literature and the authors' experience, the value of this test for patients who have acute leukemia does not appear to be well established.

An investigation of the chemical environment and growth of Legionella pneumophila in plumbing systems was conducted to gain a better understanding of its ecology in this habitat. Water samples were collected from hospital and institutional hot-water tanks known to have supported L. pneumophila and were analyzed for 23 chemical parameters. The chemical environment of these tanks was found to vary extensively, with the concentrations of certain metals reaching relatively high levels due to corrosion. The effect of various chemical conditions on L. pneumophila growth was then examined by observing its multiplication in the chemically analyzed hot-water tank samples after sterilization and reinoculation with L. pneumophila. L. pneumophila and associated microbiota used in these experiments were obtained from a hot-water tank. These stains were maintained in tap water and had never been passaged on agar. The results of the growth studies indicate that although elevated concentrations of a number of metals are toxic, lower levels of certain metals such as iron, zinc, and potassium enhance growth of naturally occurring L. pneumophila. Parallel observations on accompanying non-Legionellaceae bacteria failed to show the same relationship. These findings suggest that metal plumbing components and associated corrosion products are important factors in the survival and growth of L. pneumophila in plumbing systems and may also be important in related habitats such as cooling towers and air-conditioning systems.

The growth of a vitamin K-requiring strain of Bacteroides melaninogenicus was promoted by some postulated and proven biosynthetic precursors of bacterial menaquinones, 1,4-dihydroxy-2-naphthoic acid, shikimic acid, chorismic acid, and 4(2'-carboxyphenyl)-4-oxobutyric acid. Growth of the organism with [2',4-(14)C(2)]-4(2'-carboxy phenyl)-4-oxobutyric acid as the vitamin K replacement gave rise to a mixture of radioactive menaquinone-9 and menaquinone-10; the dilution factor for this incorporation was 1.8.

Pan, Sylvia F. (University of Pittsburgh, Pittsburgh, Pa.), Robert B. Yee, and Horace M. Gezon. Studies on the metabolism of Shigella. IV. Nutritional requirements of Shigella flexneri serotype 3. J. Bacteriol. 83:61-65. 1962.-A study of the nutritional requirements of five strains of Shigella flexneri serotype 3 was carried out. Four of the strains could be cultured in a synthetic medium composed of a mineral salts glucose base, NH(4)H(2)PO(4) or an amino acid as the nitrogen source, and nicotinamide; the fifth one required the presence of both NH(4)H(2)PO(4) and an amino acid in the medium. Variation among the former strains in their nitrogen and vitamin requirements was observed. The least fastidious one produced maximal growth using the simple ammonium salt as its source of nitrogen and did not require the addition of nicotinamide. Two strains were moderately fastidious, producing better growth within 24 hr in the presence of l-aspartic acid instead of NH(4)H(2)PO(4), and requiring nicotinamide as an accessory growth factor. The fourth strain was extremely fastidious, growing poorly or not at all in the synthetic medium. Incubation of large inocula of the fastidious strain in synthetic medium and over a prolonged period resulted in adaptation of the organism to the medium. Some of the adapted cultures grew readily in the presence of NH(4)H(2)PO(4) and did not require nicotinamide.

Virulent, avirulent, and attenuated hybrid strains of Shigella flexneri 2a are equally susceptible to phagocytosis by cultured mouse peritoneal macrophages. The virulent strain is highly lethal for the macrophages, whereas the avirulent is not and is killed. The attenuated hybrid strain is intermediate in its lethality. Comparable results were obtained by using virulent and avirulent S. flexneri 1b, 3, and 5. Destruction of macrophages occurs shortly after infection, suggesting virulent strains may possess a toxic component. The relationship of the ability to kill macrophages with multiplication of virulent shigellae in mucosal tissue is discussed.