We examined the β-lactams-resistant bacteria in human saliva. Saliva was gathered from adult men at rest and dropped on to agar plates containing ampicillin (ABPC), cefaclor (CCL), or cefteram (CFTM). Colony, growing anaerobic cultured and drug-selected bacteria were examined for identification, β-lactamase producfivity, and ABPC, cefazoline (CEZ), CCL, and CF114 MICs. In 12 cases, ABPC, CCL, or CFTM-selected bacteria were gathered for 39, 45, or 46 strains, and β-lactamase producers were 21, 2, or 3 strains each. Facultative anaerobic Gram-positive rods were the most frequent bacteria in ABPC selected, followed by obligate anaerobic Gram-negative rods. Facultative anaerobic Gram-positive cocci were the most frequent bacteria followed by facultative anaerobic Gram-negative rods in CCL selected. Facultative anaerobic Gram-positive rods were the most frequent, followed by facultative anaerobic Gram-negative cocci in CFTM selected. MIC₈₀ of each of the 4 drugs against ABPC or CFTM-selected bacteria were distributed from 64 to >256μg/mL, and ABPC was 16μg/mL and the remaining 3 drugs were 256μg/mL against CCL selected.β-Lactarnase producers, and penicillins and cephems-resistant strains were selected by ABPC, β-lactamase nonproducers, and cephemsresistant strains were selected by CCL, and β-lactamase nonproducers, and penicillin's and cephems-resistant strains were selected by CFTM. When we select the drug-resistant bacteria using by drugs, we have to take care that, various bacterial species, resistant trend, and resistant mechanism, caused by using various drugs.

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The effectiveness of antibacterial agents against 57 strains of clinically isolated multiple-drug resistant Pseu-domonas aeruginosa (MDRP) was measured by the micro-dilution method. The MIC₉₀ (the minimum inhibitory concentration of an antibiotic required to inhibit the growth of 90% of bacterial strains) values of imipenem, amikacin, and ciprofloxacin were found to be 128, 128 and 64μg/ml, respectively. All 57 strains produced metallo-beta-lactamase, and the IMP-1 gene was detected by the polymerase chain reaction (PCR). The in vitro combined effects of the antibacterial agents were tested against 25 strains of MDRP selected by the checkerboard method after evaluation by the fractional inhibitory concentration (FIC) index. Combinations of BIPM and GM, CPFX and AZT, and CPFX and GM were found to be effective against all 25 MDRP strains. Synergy or additional effect of treatment with the combination of CPFX and AZT was observed in 64% of the strains, and there were no antagonistic effects against any MDRP strains.
We investigated DNA polymorphism in all 57 strains of MDRP by pulsed field gel electrophoresis (PFGE), and 20 of DNA polymorphisms were separated by PFGE. Ten strains of type F and 7 strains of type J were isolated from patients in the internal medicine unit of our institution, and 6 strains of type G and 7 strains of type P were isolated from patients in the surgery unit. Ten of 57 patients were diagnosed with MDRP infection and the remaining 47 were concluded to be colonized by MDRP. Eight of the 10 cases of MDRP infection were diagnosed with urinary tract infection, and the other 2 with sepsis. All 8 patients with urinary tract infection caused by MDRP survived, but both patients with MDRP sepsis died.

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We investigated drug-susceptibility of Neisseria gonorrhoeae strains, which were isolated from the urethras and pharynx of the male patients with urethritis between 1999 and 2004, against cefixime (CFIX), cefteram pivoxil (CFTM-PI), ceftriaxone (CTRX), cefodizime (CDZM), spectinomycin (SPCM), levofloxacin (LVFX). Among these strains, 10 strains, which were highly resistant to CFIX (MIC≥0.5μg/mL), were analyzed their gene pattern using pulsed-field gel electrophoresis (PFGE). Drug-resistant rates in 2004 against CFIX, CFTM-PI, CTRX, CDZM, SPCM and LVFX were 5.9%, 20.8%, 0%, 0%, 0%, and 80.2%, respectively. MICs 90 against the strains isolated in 2004 did not change compared to those in 2003. MICs against four strains isolated from pharynx were twice higher than those from urethras. The incidences of β-lactamase producing strain were 2.4% in 1999, 5.2% in 2003, 5.0% in 2004, respectively. From gene analysis using PFGE, four gene patterns were recognized. Among them, 7 had the same gene pattern, which was detected from the strains isolated in each year and from different areas, indicating that this appearance of CFIX-resistant strains was not due to an outbreak of the same clone.

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[in Japanese]

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