Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effective treatment of acute bacterial exacerbations of chronic bronchitis (ABE) reduces the number of such exacerbations in such patients and may decrease or eliminate background symptoms and improve pulmonary function. The pathologic and physiologic abnormalities of the bronchial system in chronic bronchitis that predispose to bacterial infection probably include impaired mucociliary clearance, obstructed bronchioles, and bacterial infections of the bronchial epithelium. Exacerbations of bronchopulmonary symptoms are usually observed with ABE, although these symptoms are not unique to ABE. While culture and sensitivity testing is not usually required, microscopic examination of sputum is critical to determine the presence of bacterial infection. Bacteria in numbers significantly above the levels present when the patient's condition is stable and at least a doubling of the sputum neutrophil inflammatory level are essential criteria. Bacterial species observed with ABE include Haemophilus influenzae, Haemophilus parainfluenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Neisseria species, with a lesser incidence of Klebsiella and Pseudomonas species. One or more elements of background therapy for ABE should accompany antimicrobial therapy, for example, physiotherapy, bronchodilators, and so forth. Ampicillin is effective, safe, economical, and thus remains the drug of choice for ABE. Quinolones are an effective alternative when ampicillin cannot be tolerated or if organisms are resistant. Dosing is at the upper range of recommendations, and the chosen drug should be given for a 10-14-day regimen. Patients should be reevaluated if symptoms and physical findings do not return to baseline after 5-7 days.
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PMID:Treatment of acute exacerbations of chronic bronchitis: state of the art. 176 8

The E-test (PDM Epsilometer; AB Biodisk, Solna, Sweden) is an antimicrobial agent gradient-coated plastic test strip which allows MIC determinations on agar media. The test is performed in a manner similar to the agar disk diffusion procedure. A collection of Haemophilus influenzae and Streptococcus pneumoniae strains possessing various resistance mechanisms was used to evaluate the E-test method. H. influenzae strains were tested with both Haemophilus test medium (HTM) and PDM ASM II chocolate agar, while the S. pneumoniae strains were tested on Mueller-Hinton sheep blood agar. E-test MICs for a total of 10 antimicrobial agents were compared with broth microdilution MICs determined according to National Committee for Clinical Laboratory Standards methods. In general, E-test MICs for both species were quickly and easily interpreted and agreed within one log2 MIC increment in 89.8% of tests with H. influenzae and in 80.4% of pneumococcal tests. The majority of disagreements between the E-test and conventional MICs occurred with trimethoprim-sulfamethoxazole because of trailing and diffuse E-test MIC endpoints with both species. Ampicillin MICs for beta-lactamase-producing H. influenzae determined by the E-test differed at times from those determined by conventional testing because of the vagaries of interpreting colonies growing within the E-test inhibition ellipses. E-test penicillin MICs for pneumococci tended to be 1 to 2 log2 dilutions lower than those determined by using Mueller-Hinton broth supplemented with lysed horse blood. Nevertheless, strains of both species with documented resistance to the study drugs were detected by E-tests, i.e., 0.7% of the tests had very major errors with H. influenzae and 0.8% had very major errors with S. pneumoniae. Thus, the E-test represents a potential alternative method for antimicrobial susceptibility testing of these two fastidious bacterial species.
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PMID:Quantitative antimicrobial susceptibility testing of Haemophilus influenzae and Streptococcus pneumoniae by using the E-test. 199 44

Respiratory tract infections (RTIs) are the primary cause of antibiotic use in general practice. Since the first penicillin was introduced for therapeutic purposes, several classes of antibiotics have been used in the treatment of community-acquired RTIs. The phase when penicillins G and V could be active in RTIs was relatively short lived due to the early emergence of resistant organisms. Ampicillin and amoxicillin have been used successfully for more than 20 years in the treatment of RTIs. In the late 1950s and 1960s, erythromycin, tetracyclines, and co-trimoxazole were also prescribed for RTIs. In the 1970s, other molecules belonging to the cephalosporin class of antibiotics, such as cephalexin, cephaloglycin, cefadroxil, and cephradine, were introduced in general practice for the same indication. Susceptibility of the predominant respiratory pathogens to these antimicrobial agents lasted for many years. However, Haemophilus influenzae responded poorly to erythromycin, and up to 30% of pneumococcal and streptococcal strains are resistant to macrolides, tetracyclines, and co-trimoxazole. Since 1976, increasing percentages of beta-lactamase producers (up to 20% in 1989) were found among Haemophilus species, and Moraxella catarrhalis, a frequent beta-lactamase producer, is increasingly isolated as a respiratory pathogen. These problems have led to the development of additional compounds, most characterized by their stability in the presence of beta-lactamases, such as amoxicillin + clavulanic acid, or exhibiting relative resistance to enzymatic inactivation, such as cefaclor. Treatment today of most RTIs also takes into account the cost-effectiveness relationship of these antibiotics.
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PMID:Continuous activity of significant antibiotics. 202 22

Triplicate susceptibility tests were performed in each of three laboratories with 45 strains of Haemophilus influenzae and a single lot of Haemophilus test medium (HTM) agar plates. Using clarithromycin, erythromycin and chloramphenicol discs. zone sizes varied over ranges averaging only 4.3-5.8 mm. Ampicillin zone sizes were more variable, especially when beta-lactamase-producing strains were being tested, but the latter strains were consistently categorized as being resistant. A 94% interpretive consistency was observed with the two macrolides.
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PMID:Reproducibility of disc susceptibility tests with Haemophilus influenzae. 203 35

Non-beta-lactamase-mediated insusceptibility to beta-lactams was studied in Haemophilus influenzae. Mutants resistant to ampicillin were selected in a susceptible isolate, while phenotypically similar resistance was transformed from four wild-type isolates into a susceptible recipient. Ampicillin-selected mutants generally had reduced susceptibility to penicillins, cephalosporins and aztreonam. Reduced susceptibility to meropenem was less common, and susceptibility to imipenem was unaffected. MICs of three cephalosporins and aztreonam were much higher for the ampicillin-resistant transformants than for the recipient strain, and were generally equal to, or within one doubling dilution of, the concentrations that inhibited the donor parents. In contrast, reduced susceptibility to imipenem observed with one parent (MIC of 4 mg/l) was not transferred to the recipient (MIC of 0.5 mg/l). Meropenem inhibited 22 of 24 transformants tested at less than or equal to 0.12 mg/l, compared with MICs of greater than or equal to 0.5 mg/l for the donor parents and 0.03 mg/l for the recipient. These results indicated that the mechanisms that confer non-beta-lactamase-mediated insusceptibility to penicillins, cephalosporins and aztreonam in H. influenzae have little or no effect on susceptibility to carbapenems.
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PMID:Selection and transformation of non-beta-lactamase-mediated insusceptibility to beta-lactams in Haemophilus influenzae: lack of cross-resistance between carbapenems and other agents. 208 16

We compared results of MIC and disk susceptibility tests on Haemophilus test medium (HTM) and those on comparative media. Ampicillin MICs were determined with seven ampicillin-resistant, non-beta-lactamase-producing (AmprNBLP) isolates by using HTM and supplemented brain heart infusion (sBHI) agar. Ampicillin and amoxicillin-clavulanate disk tests with 16 AmprNBLP strains, 18 ampicillin-susceptible (Amps) isolates, and 17 ampicillin-resistant, beta-lactamase-producing (AmprBLP) strains were performed by using five media: laboratory-prepared HTM (PHTM), commercial HTM (CHTM), sBHI, enriched chocolate agar, and Mueller-Hinton chocolate agar. We observed that five of seven and three of seven AmprNBLP strains were misclassified as susceptible with PHTM (MIC, less than 2 micrograms/ml) with inocula of 10(3) and 10(5) CFU, respectively, but were resistant with sBHI (MIC, greater than or equal to 2 micrograms/ml). Whereas Mueller-Hinton chocolate agar and enriched chocolate agar plates supported the growth of all 51 strains by the disk tests, 37% (19 of 51) and 8% (4 of 51) of strains did not grow on PHTM and CHTM, respectively. Lack of growth on PHTM was observed for all three phenotypes; 7 of 18 Amps, 4 of 17 AmprBLP, and 8 of 16 AmprNBLP strains did not grow. The four strains that did not grow on CHTM were all AmprNBLP isolates. Zone sizes were significantly larger on PHTM than on the other media. Of the strains that were evaluable by the new National Committee for Clinical Laboratory Standards guidelines with either PHTM or CHTM, all Amps strains were classified as susceptible. Among the AmprBLP strains, CHTM correctly identified all as resistant, whereas PHTM detected two isolates to be intermediate. Among the AmprNBLP strains, CHTM and PHTM misclassified four (33%) and five (62%) isolates, respectively, as susceptible; an additional isolate was identified as intermediate on both media. We conclude that there is strain-dependent growth on HTM, that adoption of this medium for routine Haemophilus susceptibility testing is problematic due to this growth variability, and that detection of AmprNBLP isolates would be unreliable.
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PMID:Problems with current recommendations for susceptibility testing of Haemophilus influenzae. 222 55

We determined the MICs of ampicillin, methicillin, cefaclor, cefixime, cefteram, ofloxacin and ciprofloxacin against a total of 1,448 strains from 11 species: 464 strains of Staphylococcus aureus, 306 strains of Streptococcus pneumoniae, 114 strains of Streptococcus pyogenes, 37 strains of Branhamella catarrhalis, 329 strains of Haemophilus influenzae, 32 strains of Escherichia coli, 66 strains of Klebsiella pneumoniae, 26 strains of Enterobacter cloacae, 20 strains of Serratia marcescens, 12 strains of Pseudomonas aeruginosa and 42 strains of Acinetobacter calcoaceticus, isolated from the throat swab and the sputum of 2,539 patients with respiratory infections who visited 21 private clinics in Tohoku district of Japan during the period from January to April in 1989. Ciprofloxacin and ofloxacin were more active against S. aureus, B. catarrhalis, P. aeruginosa and A. calcoaceticus than other antibiotics. Ampicillin and cefteram were more active against S. pneumoniae and S. pyogenes than other antibiotics. New-quinolones and cephems of new-generation were active against H. influenzae, E. coli, K. pneumoniae, E. cloacae and S. marcescens. Of 30 strains of S. aureus which were resistant (MIC greater than or equal to 12.5 micrograms/ml) to ampicillin, only one strain was resistant (MIC greater than or equal to 12.5 micrograms/ml) to methicillin. Twenty strains (6.5%) of S. pneumoniae and 49 strains (14.9%) of H. influenzae were resistant (MIC greater than or equal to 1.56 micrograms/ml) to ampicillin. Of 101 strains of H. influenzae of which their beta-lactamase activity was determined by Nitrocephin-method, 27 (26.7%) were beta-lactamase-positive strains. The above results indicated that MRSA is only rarely found in primary care clinics but the incidence of ampicillin-resistant H. influenzae in primary care clinics is almost the same as that of the intensive care clinic, i.e. medical school-affiliated hospitals. Therefore caution should be exercised as regards antibiotic resistance of the causative organism even in primary care clinics.
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PMID:[Studies on respiratory infections in primary care clinic (IV). Antibiotic sensitivity of bacteria isolated from patients with respiratory infections visiting 21 private clinics in the Tohoku District of Japan]. 224 94

Ampicillin-resistant, non-beta-lactamase-producing isolates of Haemophilus influenzae contain a variety of penicillin-binding protein (PBP) patterns that differ from the single pattern of eight PBPs characteristic of susceptible strains. During genetic transformation of resistance, only some of the anomalies in PBP pattern were transformed, specifically those relating to the penicillin-binding capacities of PBPs 4 (Mr of 62,000) and 5 (Mr of 59,000) and, in some transformations, PBP 3 (Mr of 71,000). Comparison of the binding of penicillin by PBPs 4 and 5 of three resistant transformants (derived with DNA from different donors) revealed a decrease in the rate of PBP acylation and no appreciable change in the rate of deacylation as compared to the susceptible recipient. Thus, rapid turnover of these PBPs does not play a role. Retransformation studies confirm that altered PBPs 3, 4, and 5 are associated with resistance and suggest that these PBPs are major targets for the beta-lactam antibiotics in H. influenzae.
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PMID:Penicillin-binding proteins and ampicillin resistance in Haemophilus influenzae. 235 23

Ampicillin killing curve patterns for 20 strains of ampicillin-susceptible nontypeable Haemophilus influenzae were determined by the agar dilution plate count method. The paradoxical effect was detected in the 24-h killing curve patterns for each strain. For the biphasic effect, minimum survivor percentages (maximum killing) occurred over a narrow range of ampicillin concentrations immediately above the MIC, with survivor percentages then rising rapidly to peak at approximately 1-log10-unit increment higher. The 24-h minimum survivor percentages for the 20 strains ranged from approximately 0.01% (rapid killing) to greater than 10% (slow killing). In comparison with the previous results for typeable strains, the present findings suggest that nontypeable stains are, on average, killed much more slowly. Based on the initial 24-h killing curve patterns for the 20 strains, 4 strains were selected as putative representatives of the range of bactericidal responses encountered. These strains were then studied to examine the reproducibility of the 24-h patterns and to determine sequential killing curves. These patterns were found to be reproducible and served to characterize the relative killing responses of the strains. In the sequential studies of three of the four strains, tiny colonies having the gross and microscopic characteristics of L-forms were found to be present on the agar dilution plate count plates prior to the application of penicillinase at 48 and 72 h. Such colonies reverted to vegetative forms within 24 to 48 h after application of penicillinase to the panels. Of particular interest was the observation that the paradoxical effect was manifested both by the L-form colonies and by the reverted vegetative colonies. The late development of L-forms was observed for both rapidly and slowly killed strains.
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PMID:Ampicillin killing curve patterns for ampicillin-susceptible nontypeable Haemophilus influenzae strains by the agar dilution plate count method. 239 67

Cefixime activity has been determined against Haemophilus influenzae strains producing or not beta-lactamase, or resistant to ampicillin by non-enzymatic mechanism. All strains are inhibited by a concentration of 1 mg/l of cefixime independently of beta-lactamase secretion. Ampicillin-resistant non beta-lactamase producing strains are inhibited by concentrations of 0.12 - 1 mg/l. MIC50 and MIC90 were, respectively, 0.06 and 0.12 mg/l for ampicillin-susceptible strains and 0.12 and 0.12 mg/l for ampicillin-resistant strains. The activity of cefixime against Haemophilus influenzae was superior to that of other orally administered antibiotics tested in this study: amoxicillin, amoxicillin-clavulanic acid, cefaclor and cefuroxime.
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PMID:[In vitro effect of cefixime against Haemophilus influenzae]. 253 May 29


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