A total of 341 strains of Serratia marcescens isolated from clinical specimens in 1977 was examined for their sensitivities to various antibiotics. The results in comparison with those of older isolates were described in the preceding report. It was found that more of the new isolates than of the old ones were resistant to gentamicin, nalidixic acid and miloxacin. As the increase in number of GM-resistant strains was prominent, these isolates were re-examined for their sensitivities to aminoglycoside antibiotics. Strong antibacterial activities were shown with gentamicin, KW-1062 and sisomicin. There were, however, many strains that were resistant to these antibiotics; 41% of the strains tested was resistant to gentamicin, 47.7% to KW-1060, and 50.9% to sisomicin.
Many of the isolates from urine were resistant strains, most of which were nonchromogenic.
As to the resistant pattern, hexa-resistant strains (gentamicin, amikacin, tobramycin, dibekacin, KW-1062, and sisomicin) were most abundant, occupying 25.8%, followed by triple-resistant (amikacin, tobramycin, and dibekacin), occupying 16.8%, and penta-resistant (gentamicin, tobramycin, dibekacin, KW-1062, and sisomicin), occupying 11.8%.
A larger portion of gentamicin-resistant strains was sensitive to amikacin, but was cross-resistant to the other four antibiotics.

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Benzylpenicillin polymers were isolated from stored PCG aqueous solution, and its binding capacity to BSA was comparatively studied by two dialyzing methods.
(1) By centriflow continuous dialyzer, free PCG was filtrated out completely within 30 minutes, showing no non-specific adsorption.
(2) By dialyzing method employing seamless cellulose tube, only 10% of free PCG was filtrated out for 30 minutes.
From these results, centriflow continuous dialyzing method was used for the test of protein binding capacity of PCG polymers. The result showed that 40% of PCG polymers (2mg) was bound to BSA (1mg), but the binding capacity did not change by increasing BSA.
These results suggested the existence of PCG polymers which did not bind with albumin.

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Opportunistic infection is an infection occurring in the host whose protective function has been decreased with a low virulent microorganism regarded usually as a nonpathogen. Most opportunistic pathogens are so low in virulence to the mouse that some treatment must be given to it to establish an experimental model for opportunistic infection.
To establish an experimental model for opprtunistic infection, leukopenia was induced by applying cyclophosphamide treatment to the mouse. Virulence of strains of various species to these mice was compared with that to nontreated control mice; senitivities of mice to the infecting organisms were compared by MLD values and their variances and therapeutic effects of antibiotics by ED₅₀ values.
Leukocyte population of the mouse was normally 5, 000-6, 500 cells/cmm, which decreased to 900 cells/cmm in 4 days after administration of cyclophosphamide at a dose of 250 mg/kg. The sensitivities of the mouse to the infectious agent increased in parallel to the dose of cyclophosphamide.
The increased sensitivity differed depending upon the bacterial species; the sensitivity to Pseudomonas aeruginosa was the highest among glucose-nonfermenting gram-negative bacilli.
The effects of chemotherapy reflected the decreased protective function of the host. ED₅₀ values of peroral penicillin, ampicillin, bacampicillin, and amoxicillin in Escherichia coil infection and those of carbenicillin and gentamicin in P. aeruginosa infection increased by 2-to 3-fold.
The above results confirmed that the host with decreased protective function is vulnerable to infection with a group of gram-negative bacilli regardad as opportunistic pathogens, and that chemotherapy becomes less effective in such cases that developing symptoms from infection.

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A novel method is described which allows estimation of the outer membrane penetrability of β-lactamase-stable β-lactams by determining antibiotic concentrations in the periplasm. The method is based on measurement of the inhibiting activity of β-lactamase-stable β-lactams on the hydrolysis of a substrate by periplasmic β-lactamase. Application of the method to carbenicillin revealed that the high level of resistance to carbenicillin of an E. coli strain acquiring the plasmid encoding ampicillin resistance resulted from the poor ability of carbenicillin to penetrate the outer membrane of E. coli.

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A new in vitro model system was devised for evaluating the bactericidal activity of antibiotics under the dynamic condition that serum levels of antibiotics after i. v. dosing are gradiently simulated. The apparatus consists of two vessels which are connected air-tightly with tubings according to a two compartment open model. These vessels correspond to the central and peripheral compartments of the pharmacokinetic model. Observed serum levels are fit to the two compartment open model. Then, the volume of medium in each vessel and flow rates of medium are estimated from the pharmacokinetic parameters. The serum levels after i. v. drip infusion of antibiotics also simulated with some modifications of this apparatus.
The bactericidal activity of cefazolin against strains of E. coli, showing different MICs was investigated with the apparatus simulating serum levels after i. v. injection to discuss relationship between the MIC and serum levels.

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In order to evaluate an appropriate chemotherapy on acute pyelonephritis and protection of the occurrence of chronic pyelonephritis, studies have been performed with experimental pyelonephritis in rabbits inoculated with E. coli NIHJ-JC 2. Ampicillin was chosen for the study and it was given to animal with various dosage. The drug levels in serum, urine and renal tissue in normal and pyelonephritic animals were measured by thin layer cup method. Animals were sacrificed one month after the bacterial inoculation and studied bacteriologically and histopathologically. The results obtained were as follows.
1. Serum levels in the normal rabbits one hour after intramuscular injection of 20 mg/kg of ampicillin ranged 15.8μg/ml, however, the serum levels obtained 3 hours later were less than MIC of the bacterial strain. Total recovery of the drug into the urine up to 5 hours marked 45%. Dose response of the serum level following i. m. administration of 100 mg/kg of the drug was proved one hour later and the serum level was kept higher than MIC even 3 hours later.
2. Early stage of inflammation in the kidney was observed 24 hours after the inoculation and acute pyelonephritis seemed to be established 48 hours later clinicopathologically. Pyelonephritic change was obviously observed 72 hours later. Severe pyelonephritic change associated with formation of diffuse microabscesses was completed one week later and findings of chronic pyelonephritis were found histopathologically one month later.
3. The more the pyelonephritic change progressed in the histopathology, the less the drug level was in the kidney, both cortex and medulla, although no significant differences of the drug level were proved in the serum and the bladder urine between the unilateral pyelonephritic and normal animals. Dose response of the drug level in the affected kidney was no longer proved in the animals given 20 and 100 mg/kg of the drug one week after the bacterial inoculation. However, the drug level in the affected kidney exceeded MIC of the inoculated bacterial strain with the administration of both 20 and 100 mg/kg of the drug.
4. No evidence of histopathological efficacies was proved in the animals treated by 20 mg/kg of ampicillin started from 48 and 72 hours after the inoculation. Enhancement of in vivo effect was studied a little in animals with combined regimen of glycyrrhizine, lysozyme and γ-globulin. Sufficient histopathological effect was observed in the animals treated by 40 mg/kg of ampicillin started from 48 hours after the inoculation as same as in the animals treated by 100 mg/kg of the drug. In the animal group treatment started from 72 hours with a dose of 40 mg/kg of ampicillin, the result was somewhat inferior to the above group. Furthermore, no histopathological response was found in animals treated by even 100 mg/kg of the drug started from one week after the inoculation. These results indicated that a large dose of chemotherapy is not always necessary in the treatment of early stage of acute pyelonephritis.
5. Histopathological findings of chronic pyelonephritis were predominantly observed one month later in the animals regardless of chemotherapeutic response. Hence the occurrence of chronic pyelonephritis in rabbits may develop in an existence of the ureteric stenosis associated with immunological response, in spite of the chemotherapeutic effect.

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In maxillary bone infection, the infectious tissue concentrations of Sulbenicillin (SBPC) in the extirpated tissue of 20 cases of dental cystic disease and 20 cases of maxillary sinus disease were studied by the thinlayer cup method one hour after a single i. v. dose of 2g SBPC.
Comparative studies were performed on 10 cases of each disease (total 20 cases) by administering SBPC combined with Serratiopeptidase (TSP), which was done orally at a daily dose of 6 tablets for 5 to 7 days before extirpation, or by administering a single dose of SBPC alone. The following results were obtained:
1) The concentration range of SBPC in dental cystic diseases was 7.13-33μg/g (average 16.6 μg/g) in the SBPC combined with TSP administration group, but 2.0-24μg/g (average 10.1 μg/g) in the single SBPC administration group.
2) The concentration range of SBPC in maxillary sinus diseases was 6.6-27 μg/g (average 13.5μg/g) in the SBPC combined with TSP administration group.
3) The concentration of SBPC in the extirpated tissue was 1/8-1/13 that of the blood levels.
4) From the above results, the comparative studies of the two groups showed that the average concentrations of the SBPC combined TSP administration group were higher than those of the single SBPC administration group.

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An anticancer drug HELPA [1-(2-tetrahydrofuryl)-5-fluorouracil, the same substance as FT-207, shortened to F-5FU] was tested in 25 cases: 8 gastric, 3 colon and rectal, 8 breast, 4 thyroid and 2 metastatic cervical lymph nodes.
To 9 cases (3 gastric, 2 breast, 2 thyroid, 1 rectal and 1 cervical malignant lymphoma), F-5FU in a dose of 800 mg was given alone during the operation. The F-5FU and 5-fluorouracil (5-FU) concentrations in the cancer tissues were higher than those which gained by the oral administration. In a case of breast cancer, the subcutaneous fatty tissues were taken at intervals during the operation. The concentrations of 5-FU in the fatty tissues were trace, 0.0342, 0.0316μg/g and trace, at 0, 15, 20 and 35 minutes after injection, respectively. A 5-FU concentration in the breast cancer tissue at 35 minutes after F-5 FU injection, it was 0.22μg/g, that of the normal breast tissue was trace, and that of the metastatic lymph node was 0.92μg/g. In a case of right thyroid cancer, the 5-FU concentrations in the cancer tissues were 0.147, 0.308, 0.224 and 0.196μg/g at 20, 30, 40 and 45 minutes after injection, respectively.
In 10 cases (3 gastric, 4 breast, 2 colon and 1 matastatic cervical cancer), Urokinase (shortened to UK) in a dose of 6, 000 to 30, 000 international units (IU) was additionally administered intravenously 5 minutes before F-5FU injection. In these cases the F-5FU and 5-FU concentrations in the cancer tissues were much higher than those in the cases of a F-5 FU injection alone. In a case of left cervical cancer, the 5-FU concentrations in cancer tissues were 3.30, 2.28, 1.40, 2.12 and 2.50μg/g at 5, 25, 30, 43 and 77 minutes after injection, respectively. The 5-FU concentrations in cancer tissues when UK was additionally administered were adirectly proportional to the dosis of UK.
In 6 cases (2 gastric, 2 breast and 2 thyroid cancer), Dextran sulfate (MDS) was added in a dose of 900 mg intravenously 5 minutes before F-5 FU injection. In these cases, the 5-FU concentrations in cancer tissues were higher than those in the cases of a F-5FU injection alone, but lower than those in the UK cases.
The effective distribution of HELPA in human cancer tissues were recognized. Moreover, reinforcement of it will be expectable by using together with UR or MDS.

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Bacteriological and clinical studies on sisomicin, a new aminoglycoside antibiotic, for infectious respiratory diseaes were carried out. Results and discussions were summarized as follows.
1. Minimum inhibitory concentration (MIC) of 13 strains of S. aureus, 5 strains of S. pneumoniae, 43 strains of Enterobacteriaceae, 16 strains of P. aeruginosa, and 13 strains of Acinetobacter which were isolated from the sputum of the patients with infectious respiratory diseaes, was determined by agar plate dilution method. Seventy percent of these 90 strains was inhibited at a concentration of less than 0.78μg/ml, and also about ninety percent of them was inhibited at a concentration of less than 3.13μg/mi.
2. Within 30 minutes after intramuscular administration of 75 mg of sisomicin for the patients with infectious respiratory diseases, serum concentrations showed maximal values, 16.3±7.5μg/ml (n=8). The concentrations in the sputum were relatively low, and the mean value showed 1.3±0.6μg/ml from one to two hours after intramuscular injection. Approximately 88 percent of sisomicin was excreted in the urine within 12 hours.
3. For clinical application of sisomicin, the sensitivity test was carried out with 6.5 mm diameter disc which contained 10 μg of sisomicin with inoculum size of 10⁴ or 10⁵ cells/cm².
Sisomicin was expected to be effective clinically, was inhibition zone size was more than 14 mm on the agar plate by the error rate-bounded classification scheme.
4. Eleven patients with respiratory diseases were treated with sisomicin. The one patient was diagnosed to be bronchopneumonia, the three patients as pulmonary suppuration, the seven patients as bronchopneumonia with acute exacerbation.
Seven cases of them were cured of their infections either bacteriologically or clinically. Two cases of them were not detected their causative agents, but showed good response with sisomicin and were cured of.
The sisomicin inhalation therapy was applied to the other two patients with chronic broncho-bronchiolitis, but this therapy failed to erradicate the causative agent, P. aeruginosa, without improvement of their clinical conditions.

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Pertussis, or whooping cough, has been reported to be increased with the decreased rate of pertussis vaccination. Antibacterial activities of β-lactams against both Bordetella pertussis (B. pertussis) and Haemophilus influenzae (H. influenzae) were restricted to ampicillin (ABPC) and its derivatives. Recently, β-lactams including an oxa-cephem have been developed, and found to be more active against H. influenzae than ABPC.
Assuming that β-lactams with high anti-H. influenzae activities have high activities against B. pertussis, minimum inhibitory concentrations (MICs) against 23 strains of B. pertussis isolated from the patients with whooping cough were determined by the agar dilution method, using “BORDET-GENGOU broth” as the inoculum and BORDET-GENGOU agar in which one of the twenty-five antimicrobial agents was incorporated, that was established in this study. The inoculum size had almost no effect on MICs of antimicrobials against B. pertussis except for piperacillin (PIPC).
In vitro activities of piperazine β-lactams (PIPC, T-1551) against B. pertussis were much superior to the other antimicrobial agents. Anti-B. pertussis activity of penicillins examined in this experiment was in the order:
PIPC (MIC:≤0.003-0.006μg/ml; inoculum size, 1 loopful of 10⁶ cfu/ml)> ABPC> penicillin G≅Sulbenicillin>Cloxacillin
Anti-B. pertussis activity of cephalosporins including an oxa-cephem was in the order:
T-1551 (MIC: 0.006-0.013μg/ml; inoculum size, 1 loopful of 10⁶ cfu/ml)>SCE-1365≅6059-S>Cefotaxime>Cefuroxime >Cefotiam≅Cefazolin≅Cephaloridine≅FK-749>Cephalexin
MICs of josamycin and minocycline were determined 0.05-0.2μg/ml in the former and 0.1-0.2 μg/ml in the latter as the inoculum was 1 loopful of 10⁶ cfu/ml, which were superior to erythromycin and doxycycline, respectively.
Structure-activity relationships of β-lactams against B. pertussis have been discussed as compared with those against H. infiuenzae with the special reference to piperazine β-lactams and (syn) methoxyimino-cephalosporins. Further in vivo and clinical studies of B. pertussis infection are warrented.

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