Yasuko Kaneko

The Effects of Temperature and pH on the Growth of Eight Enteric and Nine Glucose Non-Fermenting Species of Gram-Negative Rods

We studied the heat resistance and the range of growth temperature o gram‐negative rods to find one of the bacterial factors governing their infectivity in exogenous and endogenous infections in predisposed patients.

Conjugal Transfer of Beta-Lactamase-Producing Plasmids of Neisseria gonorrhoeae to Neisseria meningitidis

Twenty clinical isolates of beta‐lactamase‐producing Neisseria gonorrhoeae from Japanese sources were studied to define their ability to serve as donors for their plasmids in conjugation with Neisseria meningitidis. These twenty strains of N. gonorrhoeae harbored the 4.5‐megadalton (Mdal) beta‐lactamase‐producing plasmids and the 24.5‐Mdal conjugative plasmids. We found that only three of twenty N. gonorrhoeae strains showed a detectable conjugation frequency (>10‐5) with N. meningitidis as the recipient although all strains were capable of mobilizing beta‐lactamase‐producing plasmids to N. gonorrhoeae and to Escherichia coli. The 4.5‐Mdal beta‐lactamase‐producing plasmid was maintained in N. meningitidis, but the large 24.5‐Mdal conjugative plasmid has not been found in N. meningitidis transconjugants.

Relationship between Pigment Producibility and Drug Resistance in Serratia marcescens

Among the clinical isolates of Serratia marcescens, non‐pigmented cells appeared more frequently from pigmented, drug‐resistant strains than from pigmented, drug‐sensitive strains. Transfer of R plasmid from Escherichia coli to pigmented strains caused spontaneous loss of pigment producibility, whereas such spontaneous loss never occurred in fresh cultures of drug‐sensitive strains. The non‐pigmented strain was a better recipient of R plasmid from E. coli than was the pigmented strain. R plasmid was transferred from the non‐pigmented strain to the pigmented strain at a higher frequency than from E. coli to the pigmented strain. The results of the present investigation suggest that transfer of R plasmid may be one of the reasons for the significant increase of non‐pigmented, drug‐resistant strains of S. marcescens in nature.

Correlation between the in vitro and in vivo Effects of Fourteen Beta-Lactam Compounds in Mice with Systemic Infection

The in vivo effect of 14 beta-lactam compounds was compared with the in vitro effect in mice systemically infected with Pseudomonas aeruginosa E7 or Klebsiella pneumoniae 3K-25. The microorganisms were inoculated intraperitoneally, and the in vivo effect of the drug was expressed as the median effective dose (ED50) determined by subcutaneous administration of the drug 1 h after the inoculation. In the mice infected with P. aeruginosa, the ability of the drug to kill the bacteria in a short time (killing activity) was markedly correlated with the ED50 (r = -0.704), but there was no correlation with the maximum concentration, half-life or area under the curve of the drug. The coefficient of multiple correlation of the ED50 with killing activity+time above the minimum bactericidal concentration (MBC) was 0.824 (contribution rate, 67.9%). In the mice infected with K. pneumoniae, the killing activity was highly correlated with MBC (r = 0.899), and the coefficient of multiple correlations with MBC+time above MBC was 0.919 (contribution rate, 84.4%). These results suggest that beta-lactam compounds have strong bactericidal activity in mice with systemic infection and that drugs with a long time above MBC are effective for this condition.

Paradoxial effect of slime produced byPseudomonas aeruginosa on the bactericidal activity of chlorhexidine

Control 0 0 0 0 0 Alkaline phosphatase 67(98.5) 0 0 1 34(97) Estearase (C4) 68(100) 1 1 1 35(100) Lipase estearase ( C 8 ) 68(100) 1 1 1 35(100) Lipase (C14) 68(100) 1 1 1 33(92) Leueine aminopeptidase 68(100) 1 1 1 35(100) Valine aminopeptidase 51(75) I I I 34(97) Cystine arninopeptidase 41(60.3) 1 1 1 35(100) Trypsin 3(4.4) 1 0 0 5(1) Chymotripsin 0 0 0 0 2(5) Acid phosphatase 65(60.3) 0 1 1 35(100) Phosphoamidase 67 (98.5) 0 1 1 35(100) a-galaetosidase 2(2.9) 0 0 0 0 #-galaetosidase 1 ( I. 6) 0 0 0 18(51 ) #-glueuronidase 0 0 0 0 0 ,*-glueosidase 6(8.8) 0 0 1 35(100) #-glueosidase 35(51.5) 0 0 1 35(100) #-glucosaminidase 1(1.5) 0 0 0 0 a-mannosidase 0 0 0 0 25(71) a-fueosidase 0 0 0 0 0