Classification, pathogenicity, and drug susceptibility of hemolytic gram-negative bacteria isolated from sick or dead chickens

Fifteen hemolytic gram-negative bacteria were isolated from the respiratory tracts of sick birds suffering from a long-lasting respiratory syndrome or from the bone marrow of dead birds distributed in the southern part of Taiwan. These were classified as Pseudomonas aeruginosa (10 isolates), Pseudomonas fluorescens (2 isolates), Pseudomonas stutzeri (1 isolate), Pasteurella haemolytica (1 isolate), and Proteus morganii (1 isolate). Each isolate was inoculated intraperitoneally into one group of ten 4-week-old male white leghorn chickens. Mortality and lesions were scored daily for 1 week. Three of the 10 isolates of Pseudomonas aeruginosa caused 100% mortality. Six other isolates of Pseudomonas aeruginosa and the one isolate of Proteus morganii caused 50% mortality. The remaining isolates induced less than 30% mortality. The sole nonpathogenic sample was one isolate of Pseudomonas fluorescens. When therapeutic levels of 22 antibiotics or sulfa drugs were evaluated for their inhibitory activity against the 15 isolates, the most effective were apramycin (15/15), gentamicin (15/15), spectinomycin (13/15), oxytetracycline (8/15), and sulfachloropyrazine (7/15). The least effective were ampicillin, cloxacillin, and tiamulin, which were not effective against any of the isolates. The 14 other drugs were of very low (> 4/15) effectiveness. Most of the isolates studied were virulent for chickens and very resistant to currently used drugs.

Plesiomonas shigelloides--associated diarrhea

Although Plesiomonas shigelloides is considered to be a cause of diarrhea in the Orient, it has infrequently been noted to be associated with diarrhea in Taiwan. Six cases of various extent of diarrhea were found to be associated with P. shigelloides in stool culture in this department between January 1987 and December 1988. Only two of them had history of chronic diarrhea and the others had mild or even no symptom. All six strains of this organism were susceptible to most commonly used antibiotics, but resistant to ampicillin, carbenicillin, clindamycin, oxacillin, penicillin, and vancomycin. Those which required least minimal inhibitory concentration (MIC) were cefazolin, ceftazidime, cefuroxime, ciprofloxacin, and trimethoprim/sulfamethoxazole. Our experiences showed that P. shigelloides may cause mild diarrhea in normal hosts. It sometimes is an incidental finding. An oxidase test for this organism should be included as routine culture of the stool specimen, but treatment is not always necessary.

Mucosal intussusception to avoid ascending cholangitis

Many methods have been devised to prevent ascending cholangitis following Kasai's hepatic portoenterostomy for biliary atresia. To investigate the effectiveness of mucosal intussusception in preventing ascending cholangitis, 20 mongrel dogs were randomized to undergo Roux-en-Y cholecystjejunostomy and common bile duct ligation with or without mucosal intussusception. Aeromonas hydrophila was instilled into the gastrointestinal tract. Bacterial cultures were grown from samples taken from the gallbladders and lower jejunum, and blood chemistry and barium studies were performed. The barium studies showed satisfactory lack of reflux in all ten dogs with mucosal intussusception. Only two of them had positive cultures for Aeromonas from the gallbladder 3 days after bacterial instillation into the jejunum. All ten dogs in the control group had positive cultures for Aeromonas from the gallbladder. Our results showed that the mucosal intussusception group had a significantly lower rate of recovery of organisms from the gallbladder compared with the control group when the organisms were instilled into distal intestine (P less than 0.05). The method is worthy of clinical trial as a means of preventing or treating ascending cholangitis.

[Cloning and sequencing of hemolysin gene from clinical Aeromonas hydrophila]

Aerolysin is one of the important virulence factors for Aeromonas hydrophila infection. To understand the characteristics of the aerolysin gene in clinical A. hydrophila, a genomic library was constructed by using pUC19 as cloning vector. The positive clone containing the aerolysin gene was selected by the colony hybridization method, using the aerolysin probe (an 48 mer oligonucleotide) of aquatic A. hydrophila. Four positive out of 1,200 transformants were obtained from the primarily screened genomic library, and were further identified for specific binding capability by the dot blot hybridization method. One of three positive clones, designated as pAH-1, was further analyzed by the restriction mapping technique. For further sequencing the aerolysin gene nucleotides, the 3.0 kb fragment of A. hydrophila isolated from pAH-1 was cloned into pBluescriptII, pKS+, resulting in plasmid pKAH-1. Subclones of pKAH-1 were constructed and determined for the presence of 48 mer aerolysin gene sequence by dot blot hybridization method. These (subclones pKS+SS and pSK+SS) were selected for nucleotide sequencing by single-stranded dideoxy sequencing method. The nucleotide sequence similarity coefficient between clinical and aquatic strains of A. hydrophila was 76%; whereas between clinical strains of A. hydrophila and A. sobria was 71%. Since the length of the A. hydrophila DNA fragment cloned into pAH-1 is 3.0 kb, a larger size than the aerolysin gene of aquatic A. hydrophila (1.45 kb) and, also, includes 3' region of aerolysin gene in aquatic A. hydrophila, the indication is that the clone, pKAH-1, contains an entire aerolysin gene of A. hydrophila. The similarity between a small region (containing 8 amino acids) of the aerolysin in the clinical A. hydrophila and the alpha toxin of Staphylococcus aureus suggests that there is functional significance in this region.

Antibiotic combination effect on the clinical isolates of Aeromonas hydrophila

The effect of antibiotic combinations on 191 clinical strains of Aeromonas hydrophila was analysed by checkerboard microdilution methods. The combinations of antibiotics were as follows: amikacin (AN) + carbenicillin (CB), AN + cephalexin (CLX), AN + piperacillin (PIP), AN + cefoperazone (CFP), AN + ceftriaxone (ROC), gentamicin (GM) + CB, GM + CLX, GM + PIP, GM + CFP, GM + ROC, GM + tetracycline (TC). The results of this study indicated that (i) the effect of AN + CB and AN + PIP was considered synergistic (their fractional inhibitory concentration (FIC) index of less than or equal to 0.5 was equal to 85.9% and 83.2%); (ii) the combination of GM + PIP, GM + CB, AN + CLX and GM + CLX was considered additive (their FIC index of = 1 were 79.0%, 82.7%, 76.4% and 93.2%, respectively); and (iii) the combination of GM + TC, GM + CFP, AN + ROC, AN + CFP and GM + ROC was considered antagonistic (their FIC index of = 2 was 55.0%, 67.6% 61.3% 68.6% and 71.2%, respectively). AN + CB, and AN + PIP combinations revealed the highest bactericidal activity, based on conclusions drawn from the bacterial killing curve study. Therefore, it is suggested that when clinicians attempt to use a drug combination to treat infection caused by A. hydrophila, they should consider the possible outcome of antibiotic combinations and choose the appropriate therapy.

Evaluation of the effectiveness of different brands' disks in antimicrobial disk susceptibility tests

A total of 813 routine isolates of aerobic and facultatively anaerobic bacteria were employed to determine the efficacy of different branded (Oxoid, Difco, BBL) antimicrobial disks, using disk antimicrobial susceptibility tests, for a total of 22 kinds of antimicrobial disks and 10,740 antibiotic-organism comparisons. Major positive and major negative discrepancies in results were defined as a change from "susceptible" to "both resistant", and a change from "resistant" to "both susceptible" according to the National Committee for Clinical Laboratory Standards' interpretive standards for zone diameters. Minor positive and minor negative discrepancies were defined as a change from "susceptible" to "both intermediate", or "intermediate" to "both resistant"; and a change from "resistant" to "both intermediate", or "intermediate" to "both susceptible". The overall agreements of Oxoid, Difco, and BBL systems were 98%, 98.7%, and 98.4% respectively, and their differences are not statistically significant. Different kinds of antimicrobial disks' representative patterns of these three brands are further analyzed: (A) In the Oxoid series, there were 220 discrepancies. Minor negative discrepancy is predominant, most frequently related to carbenicillin (25), gentamicin (13) and cephalothin (10). Besides minor negative discrepancy, carbenicillin also had six minor positive discrepancies. Tetracyclin had ten minor positive discrepancies. (B) In the Difco series, there were 137 discrepancies. The majority of them are minor positive discrepancies. Moxalactam (11) and cefotaxime (10) are the most common antibiotics involved. (C) In the BBL series, there were 170 discrepancies. Minor positive discrepancy was the predominant one, which mostly related to carbenicillin (24), amikacin (13), and ceftizoxime (12). In addition, tetracyclin had 24 times minor negative discrepancies. Laboratory workers must pay attention to these different patterns of representation. In order to evaluate the quality of 11 pairs of the give-away and the purchased BBL disks, we also compared the results for these 813 routine isolates (a total of 5,482 antibiotic-organism comparisons). The giveaway disks demonstrated 99.1% overall agreement with the purchased disks. There were 48 minor discrepancies [26 (0.47%) minor positive discrepancies and 22 (0.4%) minor negative discrepancies]. These results allow this study to emphasize the followings in order to raise the awareness of the laboratory workers: (i) alteration of disk efficacy during transportation and storage; (ii) major considerations in choosing different brands' antimicrobial disks, and (iii) the important roles played by salespersons and pharmaceutical companies in achieving sound results.

[Haemophilus infection in chronic obstructive pulmonary disease patients]

Seventy sputum specimens from chronic obstructive pulmonary disease (C.O.P.D.) with secondary infection patients and 50 sputum specimens from C.O.P.D. patients without infection were cultured on blood agar plate, eosine-methylene blue agar plate, chocolate agar plate and selective medium chocolate agar plate. Haemophilus species was isolated from 20 specimens from C.O.P.D. with secondary infection patients. The isolation rate was 28.5%. Eight strains could produced beta-lactamase and were resistant to ampicillin (40%). One strain was resistant to ampicillin though without beta-lactamase production.

[Mosquito bite allergies terminating as hemophagocytic histiocytosis: report of a case]

A 21-year-old woman had suffered from repeated vasculitis and panniculitis with fever and chills after following mosquito bites since age 7. These manifestations were confirmed with a direct mosquito bite test during her admission to another hospital at age 17. The patient presented to our hospital with progressive dyspnea, productive cough and intermittent fever for one week. In addition to the bilateral infiltrative lesions on chest roentgenography, hepatosplenomegaly with an abnormal liver function test, pancytopenia, and elevated IgE were also detected. Blood and sputum cultures grew no microorganisms. Epstein-Barr virus-IgM, Cytomegalovirus-IgM and Mycoplasma pneumonia antibodies were all negative. Bone marrow aspiration and biopsy revealed histiocytosis with hemophagocytosis. No atypical histiocyte was found. The patient was put on dexamethasone treatment with improvement. Unfortunately, symptoms relapsed two weeks later. A repeated bone marrow aspiration and biopsy revealed a picture similar to the previous one. Despite antibiotic administration and ventilator support, a rapidly deteriorated course terminated in the patient's death by respiratory failure. Mosquito bite allergies were reported to be associated with malignant histiocytosis in Japan. However, atypical histiocytes were not found in our case upon repeated bone marrow aspirations, biopsies and skin biopsies. Mature histiocytes with hemophagocytosis were prominent instead. Reactive histiocytosis was thus favored rather than malignant histiocytosis. Although opportunistic infection cannot be excluded, we propose that a mosquito bite allergy with consequent histiocytic activation by antigen, immune complex or IgE is the possible pathogenetic mechanism for hemophagocytic histiocytosis in this patient.

Community-wide epidemiological investigation of a typhoid outbreak in a rural township in Taiwan, Republic of China

An outbreak of typhoid fever occurred in Chu-Tung township, Taiwan, with dates of onset from 6 July to 8 August, 1983. Fifty-four cases were hospitalized, of which 52 were laboratory confirmed. A chloramphenicol-resistant strain of Salmonella typhi was isolated from patients' blood samples. A community survey of 2772 people selected from 490 households by stratified systematic cluster sampling, presented an attack rate of 9.4 per 1000 and a case reporting rate of 10%. The attack rate was higher in males than females for persons younger than ten years, but was greater in females than in males aged 40 years and older. The only consistent characteristic of the early outbreak cases was drinking of tapwater (10/10, 100% versus 319/490, 65% of the controls). None of the early cases but 36% (13/36) of the late cases had drunk stream or river water. Households of early cases had better hygienic conditions than those of late cases. Laboratory examination of environmental specimens indicated Escherichia coli contamination of tapwater, well water and all stream foci associated with human activities. The epidemiological data combined with laboratory results suggested that the epidemic might be due to repeated contamination of some common source (such as municipal tapwater) and/or a variety of other vehicles.

[The ratios and kinds of clinical bacteria isolated in Taiwan's large-size hospitals]

The prevalence of clinical bacteria, as isolated from Linko Chang-Gung Memorial Hospital (2,300 beds) in the period January 1985 to December 1986 and from Taipei Veterans General Hospital (2,300 beds) during the period January 1986 to December 1986, was analyzed with the following findings: (i) The isolation ratio of anaerobic and aerobic or facultative bactria during the period of investigation were 7.8% (5,513/70,799) and 92.2% (65,286/70,799), respectively. (ii) Of the total aerobic or facultative isolates from the two hospitals, 32.9% (21,510/65,286) were Gram positive cocci and bacilli, 67.1% (43,776/65,286) were Gram negative cocci and bacilli. (iii) Of these Gram-negative bacilli, 65.2% (28,490/43,675) were Enterobacteriaceae were Enterobacteriaceae and glucose fermentative Gram negative bacilli, 32.0% (13,984/43,675) were glucose nonfermentative Gram negative bacilli, and 2.7% (1,200/43,675) were fastidious Gram negative bacilli. (iv) The more common species among the members of Enterobacteriaceae were Escherichia coli 35.7% (10,163/28,490), and Klebsiella pneumoniae 18.2% (5,186/28,490). The other common species included Enterobacter cloacae, Proteus mirabilis, Serratia marcescens, Morganella morganii, Citrobacter freundii and Proteus vulgaris. The frequencies of Salmonella species and Shigella species in these two large hospitals were up to 1.6% (456/28,490) and 0.5% (149/28,490), respectively. The most common isolate among other glucose fermentative Gram negative bacilli was Aeromonas hydrophila 3.0% (843/28,490). The finding of 0.1% (11/28,490) Vibrio alginolyticus was considered as clinically significant in Taiwan. (v) Of these glucose nonfermentative Gram negative bacilli, 69.4% (9,704/13,984) were Pseudomonas aeruginosa, 18.9% (2,637/13,984) Acinetobacter species, 10.8% (1,516/13,984) Pseudomonas species. (vi) The most common bacteria among fastidious Gram negative bacilli was Haemophilus influenzae, 96.2% (1,154/1,200). (vii) Of these Gram negative cocci, 59.4% (60/101) was Neisseria gonorrhoeae and 6.9% (7/101) N. meningitidis. (viii) The more common isolates of Gram positive bacilli included Bacillus species and Corynebacterium species (diphtheroids). (ix) Of these Gram positive cocci, the isolation rates of Staphylococcus species and Streptococcus species were 54.6% (10,838/19,827) and 45.4% (9,002/19,847), respectively. The most common isolate among Gram positive cocci was Staphylococcus aureus, 30.2% (5,994/19,847); the next, enterococcus, 24.9% (4,936/19,847); then S. epidermidis, 22.2% (4,390/19,847). The less common isolates were Streptococcus pyogenes 1.1% (212/19,847) and S. pneumoniae, 1.7% (329/19,847).(ABSTRACT TRUNCATED AT 400 WORDS)

Differential identification of Candida species and other yeasts by analysis of [35S]methionine-labeled polypeptide profiles

This paper describes a scheme for differential identification of Candida species and other yeasts based on autoradiographic analysis of protein profiles of [35S]methionine-labeled cellular proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Using ATCC strains as references, protein profile analysis showed that different Candida and other yeast species produced distinctively different patterns. Good agreement in results obtained with this approach and with other conventional systems was observed. Being accurate and reproducible, this approach provides a basis for the development of an alternative method for the identification of yeasts isolated from clinical specimens.

[Evaluation on the capability of indole pyruvic acid production by members of Proteeae on different brands of sulfide-indole-motility]

Members of Proteeae were vertically inoculated into different brands of sulfide-indole-motility (SIM) medium for evaluating the capability of IPA production. A total of 328 clinical strains of tribe Proteeae was used as tested organisms, including 186 Proteus mirabilis strains, 62 Morganella morganii strains, 31 Proteus vulgaris strains, 27 Providencia rettgeri strains, 14 Providencia stuartii and 8 Providencia alcalifaciens strains. Seven different brands of SIM medium used in this study are Kyokuto and Eiken from Japan; Gibco, Difco, Scott and BBL from U.S.A.; as well as Oxoid from England. The results indicate that SIM medium of kyokuto is the most suitable medium for Proteus spp. and Providencia spp. to produce IPA (positive rates are 95.4% and 93.0%, respectively) but not for Morganella morganii (16.1%). Eiken, Gibco and BBL SIM medium are only good for Providencia spp. to produce IPA (positive rates are 95.5%, 85.1% and 87.8%, respectively). Take account the tribe Proteeae the best SIM medium to detect IPA production was from Kyokuto (80%) and the worst was Oxoid (0.3%). Since SIM medium can constantly detect the production of H2S, the relationship between H2S and IPA was analyzed. We found that there is no obvious interaction between these two characters. Production of phenylalanine deaminase (PD) is one of the important characters for tribe Proteeae. We compared PD and IPA positive rates of each members and found that the ability to produce PD and IPA is almost identical for each member in tribe Proteeae except Morganella morganii.(ABSTRACT TRUNCATED AT 250 WORDS)

Newly made antibacterial braided nylon sutures. I. In vitro qualitative and in vivo preliminary biocompatibility study

A new type of braided nylon thread with a silver compound coating was made for the purpose of designing a biocidal suture material. The study used standard bacterial culture techniques to evaluate the antibacterial property of the new Ag-coated nylon thread. Seven types of bacterial species were tested; S. aureus, E. coli, P. aeruginosa, K. pneumoniae, S. dysenteriae, S. maruslens, and P. mirabilis. The commercial size 2/0 Nurolon suture from Ethicon served as the control. A weak direct current ranging from 0.4-400 microA was applied to the specimens to examine whether the biocidal property of silver could be enhanced by current. The antibacterial property was evaluated by the width and sterility of the clear zone in the bacterial culture plates. It was found that the new nylon thread exhibited very good to moderate bactericidal property toward these seven bacterial species. P. aeruginosa was the most sensitive species, while P. mirabilis was the least sensitive one. Application of direct current through the Ag-coated specimens positively enhanced their antibacterial property and the degree of enhancement depended on the direct current level. The material also exhibited an antibacterial property toward well-established bacterial colonies, but the effect was less strong than the case when direct current was applied simultaneously with incubation. Silver ions released from the coated nylon thread were responsible for the observed antibacterial property; and the application of a weak direct current to the material enhanced this effect. A preliminary biocompatibility study of this new material in rat gluteal muscle indicated that the new material caused less inflammatory reaction than the control Nurolon suture up to 60 days after implantation.

In vitro quantitative study of newly made antibacterial braided nylon sutures

This study was done to examine quantitatively the antibacterial property of a newly made, silver compound coated braided nylon suture and to confirm the previously reported qualitative antibacterial data. Three representative bacterial species were used and they were Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The suture specimens were embedded in a custom built plastic device filled with a fixed concentration of bacteria for predetermined periods of incubation. A direct current ranging from 0.4 to 40.0 microamperes was applied to the suture specimens. The bacterial suspension was periodically removed for a standard plate count in order to determine quantitatively the antibacterial capability of the suture specimens. The amounts of silver ions released to the medium under various direct current levels were also determined by a pH/ion meter. The antibacterial property of the suture was evident in the anode site of the material, and at a fixed current, the degree of bacteriostatic effect depended upon the type of bacterial species. For example, a difference of almost 10(3) in the number of Pseudomonas aeruginosa was observed within a period of six hours. The responses of Staphylococcus aureus and Escherichia coli to the silver compound coated nylon thread, however, were not as drastic as Pseudomonas aeruginosa. These quantitative data were consistent with the previously reported qualitative observation of the width of clear zone in bacterial culture plates. The silver ion concentration in the medium increased with increasing either the current level or time, or both. At the end of six hours, the ion concentrations were 7.3 micrograms per milliliter at 0.4 microampere, 44.3 micrograms per milliliter at 4.0 microamperes and 305.7 micrograms per milliliter at 40.0 microampere.

The effect of different brands of MacConkey and xylose lysine deoxycholate agar on the isolation of Aeromonas hydrophila

Aeromonas hydrophila has been reported to be involved in the opportunistic infection of human beings, therefore, its rapid diagnosis from the clinical specimens was considered to be extremely important for the prognosis. The effect of different brands of MacConkey (MAC) and xylose lysine deoxycholate (XLD) agars on the plating efficiency and colony size of A. hydrophila was evaluated by comparing with blood agar. Results indicate that (i) except Eiken's MAC have low plating efficiency, all the MAC from BBL, Difco, Mast, Merck, and Gibco have good plating efficiency; (ii) except Eiken's and Gibco XLD, all XLD from Difco, Mast, and Merck have larger bacterial colony size; and (iii) colonies of A. hydrophila appeared on MAC are larger than those on XLD of the same brands. We suggested that a clinical laboratory microbiologist should be alert in selecting the appropriate media to isolate the clinically important bacteria.

[Urinary tract infections and microbiological characteristics of Proteus penneri isolated in Taiwan]

Proteus penneri has been reported to be involved in urinary tract infections and calculi formation. We analyzed 2,265 positive urine cultures from patients hospitalized in Taipei Veterans General Hospital, Taiwan and found that 47 patients (2.1%) were infected by P. penneri. Most of the patients were male with age over sixty and had been treated with various kinds of antibiotics. Most of the patient's urine were collected by catheter. They were alkaline (pH 8.0) and contained amorphous phosphate, triple phosphate and protein. All the isolates of P. penneri in Taiwan showed beta-hemolysis and slight swarming on sheep blood agar plate, and exhibited a green color on upper layer of sulfide-indole-motility medium after addition of Kovacs indole reagent. Except for nitrate reduction and N2 production, the biochemical characteristics of the P. penneri isolated in Taiwan were similar to those of P. penneri isolated otherwise. The Taiwan isolates of this organism were highly susceptible to cefotaxime, cefotazidime, cefotizoxime, moxalactam, nalidixic acid; but were resistant to ampicillin, carbenicillin, cefonicid, cefoperazone, ceftriaxone, cephalexin, cephapirin, chloramphenicol, clindamycin, gentamicin, nitrofurantoin, oxacillin, piperacillin, tetracycline, tobramycin, trimethoprim-sulfamethoxazole, vancomycin, and cephalothin.

[Fatal septicemia due to Chromobacterium violaceum]

A 2-year old boy was suffered from an infection caused by Chromobacterium violaceum. This is the first case of C. violaceum infection reported in Taiwan. The boy was treated with chloramphenicol and gentamicin but died after one month of illness due to the incooperation of patient's family. The causative agent was isolated from patient's blood and scar. Complete bacteriologic characteristics and antimicrobial susceptibility pattern of this isolate are reported.

Comparative study of the biotype, hemolysin-producing capability and antibiogram of the aquatic and the clinical strains of Aeromonas hydrophila

One hundred and seventy-two Aeromonas hydrophila strains were isolated from aquatic hosts including fish, turtle, frogs, shellfish and water itself. The aquatic organisms were compared with 45 clinical strains with regard to biotype, hemolysin, and antibiogram. The carrier rate of A. hydrophila in the aquatic environment was 61.7%. Of the aquatic strains 51% were hemolysin producers, equivalent to a capability for producing enterotoxin. The hemolysin-producing capability of aquatic strains was not significantly different from that of the clinical strains. The main code numbers or biotypes of aquatic strains were 3265 (29.4%), 3065 (17.5%), 7065 (9.6%), 7265, 3225 (each 8.5%). The main code number or biotypes of clinical strains were 3265 (36.1%), 3065 (9.8%), 7261 (6.6%), 2265, 3261 and 6241 (each 4.9%). Analysis of the antibiotic susceptibility pattern of both aquatic and clinical A. hydrophila strains using the microbroth dilution method showed that there is no significant difference in antibiotic susceptibility. Most aquatic and clinical strains were highly susceptible to tobramycin, gentamicin, amikacin, cefuroxime, piperacillin, cefotaxime and cefoperazone. Most strains of aquatic A. hydrophila were highly susceptible to cefamandole and chloramphenicol; however, clinical strains were only moderately susceptible to the same drugs. Most aquatic and clinical strains were highly resistant to ampicillin, and moderately resistant to sulbenicillin. Clinical strains were moderately resistant to cephapirin; however, aquatic strains were moderately susceptible to cephapirin. Based on the above findings, we may considered aquatic environment be, at least partially, the source of clinical strains. Furthermore, biotypes of aquatic A. hydrophila do not correspond to antibiogram or hemolysin-producing patterns.

[A simple method for performing yeast carbohydrate assimilation test]

A modified auxanographic method was employed to perform carbohydrates assimilation test for 25 strains of yeasts representing the following 8 species: Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. stellatoides, C. tropicalis, Cryptococcus neoformans, and Rhodotorula glutinis. The results obtained were analyzed by comparing with the conventional auxanographic method, and it was found that the modified method was more accurate, rapid and easy in reading. The modified method was obviously easier in manipulation and more economic than that of Wickerham's broth technique and yeast assimilation agar slant technique.

Pseudomonas pseudomallei infection from drowning: the first reported case in Taiwan

We report a case of Pseudomonas pseudomallei infection, in which the patient acquired the bacteria by aspiration of river water after a drowning incident near Manila, the Philippines. The pulmonary form of melioidosis was noted at the onset, but septicemia developed at a later stage. Positive blood cultures were obtained 17 days after the accident. The patient was treated successfully with a combination of amikacin and cephalothin. This is the first report of P. pseudomallei infection documented in Taiwan.

Microbiological examination of foods sold via vending machines

A total of 153 food specimens obtained from vending machines in Taipei city were subjects for the microbiological examination. Based on the standards for total microbial counts and total coliform counts established by the Department of Public Health, Republic of China, the unsatisfactory percentage of such counts for foods sold from vending machines were: 14% for carbonated beverages, 71% for non-carbonated beverages, 73% for ice cubes, and 100% for soft ice cream. Among the non-carbonic acid beverages examined, the unsatisfactory percentage for iced coffee, cocoa, chocolate milk, and fruit milk reached 90%. Escherichia coli and fecal streptococci each were found once. None of the pathogens causing food-poisoning were found during the study. As for the sanitation control of vending machines examined, 66 to 74% percent were unsatisfactory.

[Evaluation of the GNF computer-coding system for the identification of non-fermentative Gram-negative bacilli]

In order to evaluate the effectiveness of the GNF computer-coding system for the identification of glucose non-fermenting gram-negative bacilli, we employed 406 strains of bacteria including 367 clinical isolates and 39 standard strains for testing. These strains were inoculated into the following eleven conventional biochemical test media: Triple Sugar Iron Agar, Simmon's Citrate Agar, Christensen's Urea Agar, Sulfide-Indole-Motility Medium, Semisolid Voges-Proskauer Test Medium, Moeller's Ornithine Decarboxylase Test Medium, Pyocyanin Test Medium, Oxidation/Fermentation (O/F) Glucose, O/F Fructose, Nitrate Broth, Moeller's Arginine Dihydrolase Test Medium. The results of these tests plus those from the hanging drop motility test and the oxidase test were converted into bacterial code number and then checked with the GNF computer-coding system. It was found that the first preference of agreement was 75.6%, second 15.3%, third 5.9%, and fourth or more 3.2%. In regard to the speed of bacterial identification by using the GNF system and information from hemolysis pattern and flagella stain, it was indicated that 84.7% would be correctly identified within 36-48 hours after isolation. If more confirmational tests were employed, the accurate identification rate would reach to 98.7% after 4 days of isolation. In addition, the use of the GNF computer-coding system can standardize identification procedures, shorten the identification period, and save cost in terms of materials supply, inoculation time, media preparation and media-storing space. Therefore, we conclude that the GNF computer-coding system is an effective tool in the identification of the glucose non-fermenting gram-negative bacilli.

Serotypes and biotypes and antibiotic susceptibility of Haemophilus influenzae encountered in a clinical laboratory in Taiwan

Forty-four serologically and biochemically typable Haemophilus influenzae isolates from clinical specimens in Taiwan were subjected to analysis in their relationship with source of isolation and age distribution. It was found that all isolates from blood and cerebrospinal fluid were serotype b, biotype I, and all were in children less than 4 years of age. Serotypes b and e, biotypes I and III were encountered to have the highest incidence of infection caused by H. influenzae in this area. All H. influenzae isolates were further tested for susceptibility to several selected antibiotics. All strains of this organism were susceptible to erythromycin and chloramphenicol. All but two strains were susceptible to tetracycline, whereas more strains were resistant to carbenicillin, gentamycin, keflin, and penicillin. Thirty-four percent strains were found to be resistant to ampicillin and all were beta-lactamase producer. No direct correlation between ampicillin resistance and serotypes or biotypes was recognized.

Synthesis and salvage of purines during cellular morphogenesis of Myxococcus xanthus

Intact cells of Myxococcus xanthus were examined for de novo purine synthesis and salvage utilization. The cellular uptake rates of radioactive glycine (de novo purine precursor), adenine, and guanine were measured, and thin-layer chromatography and radioautography were used to examine cell extracts for de novo synthesized purine nucleotides. Intact vegatative cells, glycerol-induced myxospores, and germinating cells of M. xanthus CW-1 were able to carry out de novo purine and salvage synthesis. Germinating cells and glycerol-induced myxospores were metabolically more active or as active as vegetative cells with respect to purine anabolism. We conclude that M. xanthus is capable of synthesizing purine nucleotides and salvaging purines throughout the glycerol version of its life cycle.

De novo purine synthesis in vegetative cells and myxospores of Myxococcus xanthus

This study was designed to determine whether vegetative cells and myxospores of Myxococcus xanthus were capable of classical de novo purine biosynthesis. To answer this question, vegetative and myxospore extracts of M. xanthus FBa were tested for their ability to synthesize the second de novo intermediate, 5'-phosphoribosylglycinamide, from beginning precursors either by way of phosphoribosyl-pyrophosphate amido transferase (EC 2.4.2.14) or ribose-5-phosphate amino transferase. Both the amido and amino transferase routes occurred in both types of extracts, and both enzymes appear to be present at about the same level (per milligram of protein) in vegetative cells, myxospores, and in a bacterial prototype, Salmonella typhimurium. The dose response of the vegetative and myxospore forms of both enzymes towards adenosine 5'-monophosphate (AMP) and guanosine 5'-monophosphate (GMP) suggests that the allosteric structure of both enzymes is changed little by sporulation. Both enzymes were inhibited to varying degrees by a variety of purine nucleotides besides AMP, GMP, and 3':5' cyclic AMP.