Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cefaclor”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources

[Enzymatic synthesis of beta-lactam antibiotics. II. Aminocephalosporins].

Enzymatic synthesis of cephalexin and cefaclor with the use of immobilized aminocephalosporin synthetase from Xanthomonas sp. as a biocatalyst was studied. The employment of a mathematical model based on the acyl-enzyme mechanism of the biocatalyst action was shown possible for the quantitative description of the antibiotic syntheses. A relationship providing determination of the complex of the physico-chemical investigations required for the enzymatic synthesis design was suggested. Kinetic and thermodynamic parameters of the processes were evaluated and the ratios of the maximum conversion of the key amino acids and the initial concentrations of the substrate and nucleophile were calculated. The regions of the model fit to the experimental data within a wide range of the substrate and nucleophile concentrations were defined. The technology for the enzymatic synthesis of aminocephalosporins exemplified by cephalexin and cefaclor was designed.

Acyltransferases↗

[Susceptibility to selected antibiotics of Yersinia enterocolitica 03 strains, carrying and not carrying plasmid pYV].

A total of 199 clinical strains of Yersinia enterocolitica serotype O3, biotype 4 were tested for their susceptibility to antibiotics (158 strains carried the virulence plasmid pYV and 41 strains did not). 114 isolates were tested by standard disk diffusion method for 21 antibiotics. Almost all tested strains were resistant to ampicillin and cefazolin and susceptible to amoxycillin/clavulanate, cefaclor, cefamandole, cefuroxime, cefotaxime, ceftriaxone, aztreonam, imipenem, gentamicin, amikacin, netilmicin, tetracycline, doxycycline, chloramphenicol, ciprofloxacin, sulphamethoxazole, co-trimoxazole, trimethoprim and furazolidone. In addition minimal inhibitory concentrations (MICs) of 15 antibiotics were determined by agar dilution method for all 199 strains (158 plasmid positive and 41 strains plasmid negative). Third-generation cephalosporins such as cefotaxime and ceftriaxone and a fluoroquinolone (ciprofloxacin) were the most active antimicrobial agents, tested followed by aztreonam, imipenem, trimethoprim, tetracycline, gentamicin, chloramphenicol, amoxycillin/clavulanate, cefaclor, cefuroxime, amikacin, furazolidone and sulphamethoxazole. The present study demonstrated a high susceptibility of clinical strains of Y. enterocolitica to most of the tested antibiotics. In general, there was no significant difference between susceptibility of virulence plasmid pYV positive and virulence plasmid negative strains to antibacterial agents.

Drug Resistance, Microbial↗

Localized pustulosis induced by betalactams.

Localized forms of pustular drug eruptions related to antibiotics are uncommon and their mechanism is still unknown. We describe herein a patient who developed numerous pin-head pustules without erythema in the peribuccal area after ingestion of ceftibuten and amoxicillin. The relationship with these drugs was confirmed by single-blind oral challenges. The following tests were performed: prick and intradermal tests with benzylpenicilloyl polylysine, minor determinant mixture, benzylpenicillin and amoxicillin; patch tests were also carried out with benzylpenicillin, amoxicillin, cloxacillin, cefuroxime, ceftriaxone, cefazolin, ceftibuten and cefaclor. All cutaneous tests were negative. Controlled single-blind challenge tests were performed with amoxicillin, cefadroxil, ceftibuten, cefuroxime, cefaclor, erythromycin and ciprofloxacin. All betalactam antibiotics tested gave a positive reaction, with good tolerance of other antibiotics; this would appear to indicate a specific mechanism of hypersensitivity and not an unspecific reaction to wide spectrum antibiotics.

Adult↗

Comparative In Vitro Activities of Moxifloxacin (Bay 12-8039) and Other Antimicrobial Agents Against Respiratory Tract Pathogens in Brazil.

Clinical isolates of respiratory tract pathogens were susceptibility tested against six different antimicrobial agents. The in vitro activity of moxifloxacin was compared with that of levofloxacin, cefaclor, amoxicillin-clavulanate acid, azithromycin and trimethoprim-sulfamethoxazole against 111 isolates, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and other species isolated from respiratory tract infections. All isolates were susceptible to moxifloxacin, except for two isolates of Pseudomonas aeruginosa which showed intermediate-resistance (MIC=6µg/mL), and one isolate of Escherichia coli which showed resistance (MIC>32µg/mL). Only moxifloxacin and amoxicillin-clavulanic acid were active against 100% of S. pneumoniae isolates at the suceptible breakpoint (MIC90, 0.25 µg/mL and 0.064 µg/mL respectively). The rank order of the activity among this group of drugs against S. pneumoniae was as follows (% of susceptibility): moxifloxacin = amoxicillin-clavulanic acid (100%) > levofloxacin (97%) > cefaclor (71%) > trimethoprim-sulfamethoxazole (54%) > azithromycin (53%). Except for trimethoprim-sulfamethoxazole, all antimicrobial agents were 100% active against H. influenzae and M. catarrhalis. The fluoroquinolones, moxifloxacin and levofloxacin, were the most potent compounds against these pathogens (MIC(90) 0.032 0.19 µg/mL). These in vitro susceptibility testing data of moxifloxacin support the view that this fluoroquinolone will have an important therapeutic role in the treatment of respiratory tract diseases.

Journal Article↗

Prevalence of antimicrobial resistance of Streptococcus pneumoniae in Chinese children: four hospitals surveillance.

OBJECTIVE: To investigate the nasal carriage of antibiotic-resistant pneumococci in children of < 5 years old in the following four cities, Beijing, Shanghai, Guangzhou and Xi'an. METHODS: A total of 647 pneumococci strains were isolated and detected. Minimal inhibition concentrations (MICs) of antibiotics were determined by E-test. Disk diffusion test was used for the measurement of antimicrobial susceptibility. RESULTS: Prevalence of penicillin non-susceptible Streptococcus pneumoniae in the four cities was 41%, with Guangzhou (60.8%) ranking first, followed by Xi'an (45%), Shanghai (37%) and Beijing (25.9%). The majority of penicillin non-susceptibility isolates (23.9% - 53.8%) had a low level of resistance (MIC 0.64 - 1.5 microg/ml). The most sensitive antimicrobials in terms of percentage of susceptible organisms were amoxicillin-clavulanic acid (99.4%), followed by ceftriaxone (92.1%); cefurxime and cefaclor were slightly more sensitive than penicillin with susceptibility of 74.8% and 77.9%. Erythromycin, tetracycline and TMP-SMZ were highly resistant (83.6%, 82.1% and 76.2% respectively). Among erythromycin resistant isolates, 100% were resistant to azithromycin, 98.6% to clarithromycin, 97.2% to roxithromycin and spiramycin, and 96.6% to clindamycin. 97.2% (141/145) were typical of the macrolides-lincosamides-streptogramons B (MLSB) resistance phenotype, and 2.8% (4/145) were M phenotype. The group of PRSP was with significantly higher rates of non-susceptibility for ceftriaxone (18.4%), cefurxime (58.6%), cefaclor (53.4%), compared with the group of PEN-S (0.5%, 1.8% and 0.2%, respectively) and the rate of multi-drug resistance in the isolates of PRSP group (92.9%) was significantly higher than that of PEN-S group (59.2%). CONCLUSION: The rates of penicillin and multi-drug resistance among isolates of pneumococci carried nasally in are high children and the high prevalence of multi-drug resistance in the Chinese population may be becoming one of the most serious problems in this century.

Anti-Bacterial Agents↗

[Beta-haemolytic group A streptococcal acute pharyngo-tonsillitis in pediatric patients: a clinical and epidemiological study].

Authors compared the efficacy and safety of 10-day regimen of Cefaclor (CEC), oral suspension, at the dose of 25 mg/kg BID, and Amoxicillin/clavulanic acid (AMC), and Erythromycin (E) both given TID at the dose of 15 mg/kg in the treatment of proven group A beta hemolytic streptococcal pharyngo-tonsillitis. Of the 673 enrolled pediatric patients, 245 were selected and assigned to three groups of treatment (85 received CEC, 78 received AMC and 82 received E) and 217 were evaluated for efficacy. Clinical evaluations were performed on days 5 and 10 of treatment and 20 days after its completion (follow up). Before treatment, on treatment day 10 and at follow up throat swab cultures were performed. In evaluable patients the post-therapy clinical success and bacteriological eradication rate for CEC was 91.8% (68 of 74 evaluable patients); the rate for AMC and E were 90.5% (67/74) and 76.8% (53/69) respectively. At follow up bacteriological eradication was observed in 63 of 68 clinically cured patients (92.6%) in the CEC treatment group; in 64 of 67 (95.5%) in the AMC treatment group and in 49 of 53 (92.4%) in the E treatment group. Adverse events occurred in 24 of 217 (11.05%) treated patients and the incidence of side effects was lower in CEC group. In vitro sensitivity tests showed 37.9% of isolated SBEGA strains resistant to macrolides and 32% of SBEGA strains resistant to tetracycline. In our experience Cefaclor administered BID is as effective and more safe than Amoxicillin/clavulanic acid and more effective than Erythromycin both given TID.

English Abstract↗

[Carrier rate of Streptococcus pneumoniae and susceptibility thereof to antimicrobial drugs among children in China: a surveillance study in Beijing, Shanghai, and Guangzhou 2000-2002].

OBJECTIVE: To investigate the carrier rate of Streptococcus pneumoniae and the susceptibility of S. pneumoniae to 10 different antimicrobial drugs among children in China. METHODS: Nasopharageal swab specimens were collected from randomly selected 3578 out-patients with upper respiratory infection aged 1 month to 5 years in Beijing, Shanghai, and Guangzhou 2000-2002 so as to isolate S. pneumoniae. The susceptibility of these strains to erythromycin and beta-lactam antibiotics (penicillin, amoxicillin/clavulanic acid, cefaclor, cefuroxime and ceftriaxone) was determinated by E-test MIC method, and the susceptibility to chloramphenicol, tetracycline, sulfamethoxazole/trimethoprim and ciprofloxacin was determinated by disk diffusion method. RESULTS: A total of 892 strains of S. pneumoniae were isolate from the 3578 children with a carrier rate of 24.9% (9.0%-36.0%). 634 isolates of S. pneumoniae were tested to examine their susceptibility to chloramphenicol, 199 to ciprofloxacin, and 887 to the other 8 antimicrobial drugs. The insusceptibility rate of S. pneumoniae to penicillin was 39.9%, and the resistance rate was 6.4%. The resistance rate to cefaclor was 20.4%. The insusceptibility rate to cefuroxime was 19.0%. The susceptibility rate to amoxicillin/clavulanic acid was 98.5% and that to ceftriaxone was 97.2%. More than 80% of the isolates were resistant to erythromycin, tetracycline, and sulphamethoxazole/trimethoprim. Chloramphenicol resistance was less common (32.3%) than the resistance to other non-beta-lactam antibiotics, except for ciprofloxacin to which the resistance rate was 2.0%. The national insusceptibility rates for beta-lactam antibiotics did not vary significantly during the three years with the widest varying range of 5.1% for penicillin (38.1%-43.2%). Each of the three cities had their different varying patterns of antimicrobial susceptibility, especially for beta-lactam antibiotics. Multi-drug resistance was common (88.7%). Strains of S. pneumoniae insusceptible to penicillin were significantly more common than those susceptible to penicillin (99.1% vs. 78.8%, chi(2) = 50.36, P < 0.001), and strains of S. pneumoniae insusceptible to erythromycin were significantly more common than those susceptible to erythromycin too (95.8% vs. 17.1%, chi(2) = 360.26, P < 0.001). CONCLUSION: Antimicrobial resistant S. pneumoniae has already become a serious problem in China. Ongoing surveillance study on the antimicrobial resistance of S. pneumoniae is necessary for appropriate antimicrobial use in clinical work and modification of medical strategies for people's health.

Anti-Bacterial Agents↗

[Surveillance of antimicrobial susceptibility of Streptococcus pneumoniae and Hemophilus influenzae isolated from children in Guangzhou area between 2003 and 2004].

OBJECTIVE: To investigate the situation of antibiotic resistance of Streptococcus pneumoniae (Sp) and Hemophilus influenzae (Hi) clinical isolates from children in Guangzhou area. METHODS: The authors cultured, isolated and identified the Sp and Hi strains from nasopharyngeal secretion of patients who visited Guangzhou Children's Hospital for upper respiratory tract infection between 2003 and 2004. K-B disc diffusion and E-test for antibiotic susceptibility were performed for these clinical isolates. RESULTS: Totally 172 and 484 strains of Sp and Hi were respectively isolated from nasopharyngeal secretions in the hospital. For Sp strains, the rates of resistance to penicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, cefaclor, erythromycin, tetracycline, chloramphenicol, sulfamethoxazole/trimethoprim (SMZ/TMP), clindamycin and ofloxacin were 32.0%, 11.1%, 32.6%, 18.1%, 39.5%, 82.6%, 78.5%, 24.4%, 87.2%, 69.2% and 3.1%, respectively. The penicillin non-susceptible Sp (PNSSP) isolates showed higher rates of resistance to other antimicrobial agents such as other beta-lactam antimicrobial agents, erythromycin, and SMZ/TMP than those of penicillin susceptible Sp (PSSP) isolates. More than 90% of PNSSP were multidrug resistant strains. The average rate of beta-lactamase production among 484 strains of Hi was 29.5% (143/484). For Hi isolates, the rates of resistance to ampicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, cefaclor, SMZ/TMP, tetracycline, chloramphenicol, azithromycin, and ofloxacin were 40.1%, 3.4%, 4.1%, 1.9%, 5.6%, 56.2%, 52.1%, 17.4%, 2.1%, and 0.6%, respectively. CONCLUSION: The antimicrobials resistant Sp and Hi isolated from children with respiratory tract infection in the area have become a severe problem. The rate of resistance to penicillin of Sp had been decreased compared with the last three years, but the rate of resistance to ceftriaxone of Sp increased, and the multidrug resistance rates of PNSSP was rather high. PNSSP was characterized by a multidrug-resistance to erythromycin, tetracycline and SMZ/TMP. beta-lactamase production and ampicillin resistance among the Hi isolates from children in the area had increased generally during the period 2003 - 2004. The Hi isolates were more susceptible to the second and the third generation cephalosporins, amoxicillin/clavulanic acid and azithromycin.

Anti-Bacterial Agents↗

[RU 51807 (cefpodoxime proxetil). In vitro and in vivo antibacterial activity of a new orally administered active cephalosporin].

Cefpodoxime proxetil (RU 51807) is an enterally absorbed ester prodrug which is rapidly cleaved in vivo after oral administration, with release of the active free acid metabolite cefpodoxime. The in vitro antibacterial activity of the sodium salt of cefpodoxime (RU 51746) against approximately 800 clinical isolates was evaluated comparatively with other orally active beta-lactams. RU 51746 was found to be active against enterobacteria normally susceptible to third generation cephalosporins, with MIC50 values ranging from 0.02 mg/l (Providencia sp) to 5 mg/l (C. freundii). RU 51746 was also active against H. influenzae, including beta-lactamase producing strains (MIC50 0.04 mg/l), oxa-S S. aureus (2,5), beta-hemolytic streptococci (0.05) and S. pneumoniae (0.002). Oxa-R staphylococci and P. aeruginosa were resistant to RU 51746 (MIC50 greater than 40 mg/l for both organisms). The antibacterial activity of RU 51746 was bactericidal in nature and independent from test conditions. The molecule was stable to all the beta-lactamases studied, with the exception of cefuroximase (type Ic). RU 51746 exhibited no strong inhibitory effects on these enzymes, except with Enterobacter P99 (type Ia). A good correlation was found between in vivo activity of RU 51807 and in vitro activity of RU 51746. Cefpodoxime proxetil was found to be more effective than cefaclor in mice with experimental septicemia caused by various streptococci, with a DP50 ratio in the 10-100 range. This advantage was again evidenced for septicemias due to various enterobacteria. In contrast, cefaclor proved more effective in experimental staphylococcus infections. In mice with experimental pneumonia, cefpodoxime proxetil caused sharp falls in K. pneumoniae lung counts. Six days after induction of the infection, 60% of animals under cefpodoxime proxetil had sterile lungs, versus 25% of animals under amoxicillin.

Animals↗

In vitro studies with Bay V 3522, a new oral cephalosporin.

The in vitro activities of Bay v 3522, cefaclor, cephalexin, cefuroxime, cefixime, amoxicillin/clavulanate (2:1) and reference penicillins were compared against 314 clinical isolates of Gram-positive and Gram-negative bacteria and nine strains of Escherichia coli that differed in their outer membrane proteins in agar dilution tests with an inoculum of 10(4) cfu/spot. The beta-lactamase stabilities of the cephalosporins were also evaluated by spectrophotometric assay using 21 different beta-lactamases. Bay v 3522 was the most potent cephalosporin overall against Gram-positive pathogens, but slightly less active than amoxicillin/clavulanate. In addition to being highly active against streptococci (MIC90 = 0.25 micrograms/ml) and methicillin-susceptible staphylococci (MIC90 = 1.0 micrograms/ml), Bay v 3522 was markedly more active than the other cephalosporins against Enterococcus faecalis (MIC90 = 4 micrograms/ml). Bay v 3522 was less potent against Gram-negative pathogens, especially nosocomial isolates of Escherichia coli and Klebsiella pneumoniae (MIC90 greater than 64 micrograms/ml), but was active against Haemophilus influenzae, Moraxella (Branhamella) catarrhalis, and beta-lactamase-negative Neisseria gonorrhoeae (MIC90 = 1.0 micrograms/ml0. Hydrolysis of Bay v 3522 by most beta-lactamases examined was significantly less than that observed for cephalothin and cefaclor; similar to that observed with cephalexin; and less than that observed with cefixime and cefuroxime. None of the beta-lactamases examined hydrolysed Bay v 3522 at a rate greater than 20 nmol/min/mg. The in vitro potency of Bay v 3522 against Gram-positive and fastidious Gram-negative pathogens and its resistance to hydrolysis by beta-lactamases produced by them support further investigation of this cephalosporin as a new oral therapeutic agent.

Anti-Bacterial Agents↗

Antimicrobial activities of six new oral cephem antibiotics.

Six newly developed oral cephem antibiotics, which included 5 with an aminothiazolyl side chain, viz., cefixime, cefotiam hexetil, cefpodoxime proxetil, cefteram pivoxil, ceftibuten, and one with a conventional side chain design, BMY 28100, were tested for their antimicrobial activities. Three traditional oral beta-lactam antibiotics, ampicillin, cephalexin, and cefaclor, were used as reference antibiotics. The 5 aminothiazolyl cephems were more active than the reference drugs against clinical isolates of Escherichia coli, Klebsiella pneumoniae and Haemophilus influenzae. All 6 new drugs showed poor activity against clinical isolates of Enterobacter cloacae, Pseudomonas aeruginosa, and enterococci. They were better than cephalexin and cefaclor, but slightly poorer than or the same as ampicillin in activities against Streptococcus pyogenes and Streptococcus pneumoniae. Cefotiam hexetil, BMY 28100, and cefpodoxime proxetil were also more active than cephalexin against Staphylococcus aureus. Although the 6 tested new oral cephems demonstrated little difference in their activities against different bacteria, they all showed greater antimicrobial activity than the traditional oral antibiotics now in clinical use.

Administration, Oral↗

[In-vitro activity of cefuroxime-axetil against pathogens of bacterial infections of the respiratory tract].

Cefuroxime-Axetil is an ester of cefuroxime, which can be used as an oral antimicrobial agent. The prodrug is hydrolysed by esterases of the gut mucosa, setting free the active cefuroxime. This second generation cephalosporin is well known since more than a decade as a cephalosporin possessing high stability against gram positive and gram negative beta-lactamases. Due to its pharmacokinetic properties and its wide spectrum of activity, cefuroxime-axetil was recommended to be used as an oral agent in bacterial infections of the respiratory tract. This paper describes the in vitro activity of cefuroxime against respiratory tract pathogens and compares it with that of ampicillin and amoxicillin, amoxicillin/clavulanic acid, cefaclor, chloramphenicol, tetracycline, erythromycin and trimethoprim/sulphamethoxazole. Cefuroxime had good activity against beta-lactamase-producing and beta-lactamase-negative H. influenzae and M. catarrhalis. As expected, the aminopenicillins showed reduced activity against beta-lactamase-producing strains of these organisms. Amoxicillin/clavulanic acid and, to a lesser degree, cefaclor also showed good activity against these bacteria. Cefuroxime was highly active against penicillin-susceptible pneumococci, but showed impaired activity against penicillin-resistant strains. Therefore, this drug should not be used in infections caused by penicillin-resistant pneumococci. Resistance to penicillin in pneumococci isolated in Switzerland is not a problem at the present time. For many years, such strains were isolated only sporadically. Cefuroxime showed also a high in vitro activity against streptococci of serogroups A, B, C and G, which are encountered as respiratory tract pathogens. Against beta-lactamase-positive and -negative staphylococci, cefuroxime showed good activity. The drug was inactive, however, against methicillin-resistant strains.

Anti-Bacterial Agents↗

[In vitro comparative effect of cefixime and 7 other beta-lactamines against Streptococcus pneumoniae].

The comparative in vitro activities of cefixime, penicillin G, amoxicillin, cefotaxime, cefaclor, cefadroxyl, cefotiam and cefuroxime against 83 recent clinical isolates of S. pneumoniae were determined. In addition, the susceptibilities of 17 relatively or fully penicillin-resistant strains of S. pneumoniae were evaluated. Cefixime was more active than the first generation cephalosporins cefaclor and cefadroxyl against penicillin-susceptible strains. The MIC50 and MIC90 obtained by the agar dilution method were 0.25 and 0.5 mg/l respectively. The MICs obtained by a microdilution technique were one dilution lower. Cefixime exhibited little or no activity against relatively or fully penicillin-resistant strains.

Anti-Bacterial Agents↗

Serotype and antimicrobial susceptibility patterns of Haemophilus influenzae isolates from inpatients and outpatients in Johannesburg.

During the 6-month period July 1987-January 1988, 934 isolates of Haemophilus influenzae were collected from 6 laboratories in Johannesburg. On the basis of counter-immuno-electrophoresis, 30 of the isolates were serotype b, with 9 of 36 (25%) cerebrospinal fluid isolates being type b. Overall, 11.7% of the isolates produced beta-lactamase. The prevalence of resistance based on a disc diffusion test was ampicillin 14%, chloramphenicol 2.3%, cefaclor 4.4%, erythromycin 84.9%, tetracycline 4.7% and co-trimoxazole 9.7%. Problems were encountered with the disc diffusion testing of augmentin- and minimum inhibitory concentrations (MICs) were determined. The MICs of 40 isolates were compared with their zone diameters. Good correlation between these two methods of antimicrobial susceptibility testing was found with all the antimicrobials tested excluding augmentin (correlation coefficient 0.1234) and cefaclor (correlation coefficient -0.2473).

Anti-Bacterial Agents↗

Comparative trials of doxycycline versus amoxicillin, cephalexin and enoxacin in bacterial infections in chronic bronchitis and asthma.

The comparative efficacy of doxycycline versus amoxicillin, cephalexin, cefaclor and enoxacin was examined in four separate cross-over and blinded studies of acute bacterial bronchitis in chronic bronchitis and asthma. The efficacy of doxycycline over the eleven-year period (1975-1986) covered by these studies also was examined. Patients with acute bacterial exacerbations, defined by increased chest symptoms, increased bacteria and sputum neutrophilia, were randomly entered. When a new acute infection occurred, they were re-entered and received the other antibacterial. Response was recorded as successful or not; early rebound infections and the periods free of infection were noted. A total of 136 exacerbations were evaluated in the comparison of doxycycline with the other 4 antibacterials, and 93 exacerbations in the long-term efficacy of doxycycline. The acute success was similar for doxycycline with the other antibacterials and was superior to cefaclor. Early rebound infections occurred less frequently with doxycycline as compared to the cephalosporins and was similar versus amoxicillin and enoxacin. The infection-free period was longer after doxycycline than with the other four antimicrobials. Doxycycline maintained its efficacy to elicit a prompt response and provide a long infection-free period, but an increase of early rebound infections was noted over the eleven-year period.

Adult↗

[Effect of cephalosporins on lymphocyte proliferation and immunoglobulin E production].

We studied the effects of three cephalosporins (cefadroxil, cefaclor, cephalexin) on an in vitro model of human mononuclear cell proliferation in response to polyclonal mitogens. Cefadroxil, and to a lesser extent cefaclor and cephalexin, induced a decrease of proliferative responses to phytohaemagglutinin and concanavalin A. This decrease was not due to a direct effect on lymphocytes, but depended on the presence of adherent monocytes in the cultures. Cephalosporins stimulated the release of prostaglandins E2 by monocytes, generating a suppressive activity. Cefadroxil and cephalexin were in vivo given to Brown-Norway rats sensitized to DNP-OVA to induce a primary and secondary IgE specific response. The administration of cefadroxil provoked a clear decrease of the secondary IgE response. As the IgE production closely depends on T suppressor cells, we hypothesize that cefadroxil could interfere with that production by stimulating a suppressor cell activity linked to an increased PGE2-release.

Animals↗

In vitro susceptibility of upper respiratory tract pathogens to 13 oral antimicrobial agents.

An in vitro comparison of the activities of 13 oral antimicrobial agents against clinical isolates of bacteria commonly responsible for causing upper respiratory tract infections was performed. With regard to Haemophilus influenzae, beta-lactamase-negative strains were susceptible to amoxycillin, augmentin, cefaclor, erythromycin, trimethoprim, cotrimoxazole and tetracycline, with CL 284,635 being the most active agent. With the exception of amoxycillin these drugs were also active against beta-lactamase-producing strains. CL 284,635 was also very active against Branhamella catarrhalis isolates, including beta-lactamase-producing strains, but was less active against the Gram-positive bacteria tested. Cefadroxil, cephradine and cephalexin were mainly active against Gram-positive pathogens. Based on minimum inhibitory concentration determinations, cefaclor, augmentin and co-trimoxazole would be appropriate drugs for the treatment of those cases of otitis media and sinusitis where H. influenzae and Streptococcus pneumoniae are important pathogens provided they are susceptible to these agents.

Anti-Bacterial Agents↗

Long-standing otitis media with effusion--a convenient model for the study of antibiotic penetration to respiratory tract secretions.

In long-standing otitis media with effusion, myringotomy with aspiration of the middle ear exsudate is an established therapeutical procedure, which can be performed under carefully planned conditions. This common disease thus offers convenient advantages for the study of antibiotic concentrations in the middle ear. This is exemplified by a review of studies with erythromycin, doxycycline and cefaclor. A delayed penetration into the middle ear was demonstrated for all these antibiotics, especially for erythromycin. The elimination from the middle ear was slower than from serum, at least with erythromycin and doxycycline. With these two antibiotics, the middle ear concentrations were close to the peak serum levels, with only small fluctuations between doses during a course of treatment. With cefaclor, peak middle ear concentrations were less than 40% of peak serum levels. By using this model, data from a natural disease in humans are obtained. Since the mucosa anywhere in the respiratory tract reacts in a uniform manner to an inflammatory stimulus, results from studies on long-standing otitis media with effusion can disclose some aspects on antibiotic pharmacokinetics in respiratory tract secretions in general.

Anti-Bacterial Agents↗