In vitro susceptibilities and beta-lactamase production of 53 clinical isolates of Branhamella catarrhalis

Abstract

We tested 53 clinical isolates of Branhamella catarrhalis recovered from patients with respiratory symptoms to determine the susceptibility of the isolates to 25 antimicrobial agents, including the newer I8-lactam antibiotics. Of the 53 strains, 46 (86.7%) were P-lactamase producers. All the strains were susceptible to the majority of the new penicillins and cephalosporins.-The combinations of amoxacillin-clavulanic acid and ticarcillin-clavulanic acid were also very active against the P-lactamase-prodiicing strains.Branhamella catarrhalis, formerly known as Neisseria catarrhalis, is generally considered a harmless oropharyngeal commensal bacterium. However, in the past few years it has been recognized as the etiologic agent of otitis media in children (9) and has been isolated in pure culture from patients with acute bronchitis and pneumonia (2,7,10,12,16,17), acute laryngitis (15), acute sinusitis (1), septicemia (3), meningitis (3, 13), and endocarditis (6, 14). P-Lactamase production by B. catarrhalis has occurred in 4 to 100% of isolates (5, 7-9, 16). Despite this fact, very little information is available on the susceptibility of B. catarrhalis to antimicrobial agents, especially the newer 1B-lactam antibiotics.We report here on the antimicrobial susceptibility and the incidence of 1-lactamase in 53 clinical isolates of B. catarrhalis from hospitalized patients with respiratory disease. Organisms. A total of 53 clinical isolates of B. catarrhalis were obtained from hospitalized patients with lower respiratory symptoms admitted to the Veterans Administration Medical Center, Johnson City, Tenn. The isolates were obtained from blood, transtracheal aspirates, and expectorated sputum from patients with pneumonia or acute exacerbation of chronic bronchitis. The clinical isolates were identified by conventional methods previously described (4): gram-negative diplococci, oxidase production, growth on 5% sheep blood agar incubated at 37°C under humidified 10% C02, lack of pigmentation, failure to produce acid from glucose, maltose, and sucrose, and reduction of nitrate to nitrite. P-Lactamase production. The production of ,B-lactamase was determined in each strain by the use of the chromogenic cephalosporin disk nitrocefin (Cefinase; BBL Microbiology Systems, Cockeysville, Md.).Antibiotics. Antibiotics were kindly provided by the manufacturers as reagent-grade powders and included penicillin

Pharmacokinetics of cefuroxime axetil suspension in infants and children

“…The amount of time during which the serum cefuroxime concentration exceeded 1 ,ug/ml increased with increasing doses of cefuroxime axetil suspension in infants and children. In addition, the mean t1/2 of cefuroxime was independent of dose and ranged from 1.4 to 1.9 h. This is longer than the t1/2s of cefaclor (42.5 min), cephalexin (0.98 h), and cephradine (1.0 h) in pediatric patients and slightly longer than the mean tl2 (range, 1.1 to 1.4 h) observed for children receiving crushed cefuroxime axetil tablets (6,7,13,14).…”

“…Therefore, the 3-h blood sample was also used to determine whether cefuroxime axetil (intact ester) was present in whole blood. Immediately after collection of the 3-h blood sample, 1 oxime concentrations of 0.15, 1.5, and 15 ,ug/ml, respectively. The interday coefficients of variation were 10.9, 3.8, and 6.3% for cefuroxime concentrations of 0.15, 1.5, and 15 ,ug/ml, respectively.…”

“…Since cefuroxime sodium is not absorbed orally (4), the 1-acetyloxyethyl ester was substituted for sodium on the cefuroxime molecule to increase its lipid solubility and improve its gastrointestinal absorption. After oral administration, cefuroxime axetil is absorbed and rapidly hydrolyzed by nonspecific esterases in the intestinal mucosa and portal blood (10) to produce concentrations of cefuroxime that exceed the MIC of common respiratory tract pathogens, including 3-lactamasepositive and -negative strains (1,11,12,17).…”

Disk diffusion susceptibility of Branhamella catarrhalis and relationship of beta-lactam zone size to beta-lactamase production

“…Since that time 3-lactamase production has spread, and many isolates now produce the enzyme (2,14,20). The 3-lactamase is cell bound and appears to be more difficult to detect than TEM-1 in Haemophilus influenzae and Neisseriae gonorrhoeae.…”

“…Since that time 3-lactamase production has spread, and many isolates now produce the enzyme (2,14,20 Cockeysville, Md.) and by the addition of extracts from acetone-treated cells (11) to a solution of nitrocephin (15).…”