SUSCEPTIBILITIES OF BACTERIA ISOLATED FROM PATIENTS WITH LOWER RESPIRATORY INFECTIOUS DISEASES TO ANTIBIOTICS (2001)

Abstract

From October 2001 to September 2002, we collected the specimen from 370 patients with lower respiratory tract infections in 16 institutions in Japan, and investigated the susceptibilities of the isolated bacteria to various antibacterial agents and antibiotics and patientsrsquo; characteristics. Of 458 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in inflammation, 456 strains were investigated. The breakdown of the isolated bacteria were: Staphylococcus aureus 69, Streptococcus pneumoniae 72, Haemophilus influenzae 85, Pseudomonas aeruginosa (non-mucoid) 44, P. aeruginosa (mucoid) 13, Klebsiella pneumoniae 32, Moraxella subgenus Branhamella catarrhalis 32, and others.
Of 69 S. aureus strains, those with 4μg/mL or more of MIC of oxacillin (methicillin-resistant S. strains: MRSA) occupied 43.5%. Vancomycin and arbekacin showed the most potent activities against MRSA as observed in 2000. The frequency of S. pneumoniae exhibiting low sensitivity to penicillin (penicillin-intermediate S. pneumoniae: PISP+penicillin-resistant S. pneumoniae: PRSP) was 59.7% and both rates of PISP and PRSP were the highest after 1992. Carbapenems had strong activities against S. pneumoniae. Especially, panipenem and imipenem inhibited the growth of all 72 strains at 0.125 and 0.5μg/mL, respectively. Generally, all drugs had strong activities against H. influenzae with MIC₉₀s of 16μg/mL or less. The drug that had the strongest activity against H. influenzae was levofloxacin, which inhibited the growth of 80 of the 85 strains at 0.063μg/mL.Against P. aeruginosa mucoid strain, meropenem had a strong activity with MIC₉₀ of 0.5μg/mL while, against non-mucoid strain, tobramycin had a strong activity with MIC₉₀ of 2μg/mL. K. pneumoniae showed good susceptibilities to all drugs except ampicillin and minocycline, and the MIC₉₀s were 4μg/mL or less. Particularly, cefmenoxime, cefpirome, and imipenem had the strongest activity (MIC₉₀: 0.125μg/mL), and cefozopran had a strong activity, inhibiting the growth of all strains at 0.25μg/mL. Also, all drugs generally had strong activities against M.(B.) catarrhalis. MIC₉₀s of all drugs were 4μg/mL or less. The drug that had the strongest activity was minocycline and levofloxacin inhibiting all 32 strains at 0.063μg/mL.
Most of the patients with respiratory infection were aged 70 years or older, accounting for approximately a half of the total (40.5%). As for the incidence by the diseases, bacterial pneumonia and chronic bronchitis were the highest, being noted in 39.2% and 37.3% of all the patients, respectively. The bacteria frequently isolated from the patients with bacterial pneumonia were S. aureus (19.3%) and S. pneumoniae (19.9%). In contrast, H. influenzae (22.0%) were frequently isolated from the patients with chronic bronchitis. Before the drug administration, the bacteria frequently isolated from the patients were S. pneumoniae (20.8%) and H. influenzae (21.5%).S. pneumoniae and H. influenzae decreased after the initiation of drug administration while S. aureus increased.The isolation frequency of P. aeruginosa was higher after than before the initiation of drug administration. The bacteria were frequently isolated from the patients who had already treated with cephems were S. aureus and P. aeruginosa. From the patients who had already treated with macrolides, S. pneumoniae was the most frequently isolated while S. aureus was the most frequently isolated from the patients pre-treated with quinolones.