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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The need for an accurate and rapid method of testing ampicillin susceptibility of Haemophilus influenzae, especially strains isolated from patients with meningitis and septicemia, is indisputable. Various methods have been employed for this purpose. Each has advantages and disadvantages. This report describes a modification of the capillary acidometric procedure in which an agar plate is substituted for a tube. All beta-lactamase results obtained by this modified technique correlated with minimal inhibitory concentrations determined in liquid media and the chromogenic cephalosporin substrate method. This modified acidometric agar procedure is a simple, inexpensive, accurate, and rapid way to determine H. influenzae susceptibility to ampicillin.
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PMID:Acidometric agar plate method for ampicillin susceptibility testing of Haemophilus influenzae. 30 20

The comparative activities of ampicillin, cefamandole, cefoxitin, cefaclor, and cefatrizine against both beta-lactamase-producing and non-beta-lactamase-producing isolates of Haemophilus influenzae were determined by using an agar dilution susceptibility test procedure. Ampicillin was the most active drug tested against non-beta-lactamase-producing isolates, whereas cefamandole was most active against beta-lactamase-producing strains.
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PMID:Comparative activities of selected beta-lactam antibiotics against Haemophilus influenzae. 30 21

The in vitro activity of cefamandole was determined against 58 isolates of Haemophilus influenzae type b; 47 were beta-lactamase-negative (ampicillin-susceptible), and 11 produced beta-lactamase (ampicillin-resistant). Ampicillin-susceptible strains were susceptible to cefamandole with a median minimal bactericidal concentration (MBC) of 0.4 microgram/ml. Ampicillin-resistant strains had a median MBC of 0.8 microgram/ml. Prior studies have documented these concentrations of cefamandole in cerebrospinal fluid in the presence of inflamed meninges. Three children with meningitis due to H. influenzae type b were treated with cefamandole (200 mg/kg per day), including one child with disease due to an ampicillin-resistant strain. All patients showed clinical improvement during therapy. However, sterility of the cerebrospinal fluid was never achieved in two patients during 72--96 hr of therapy with cefamandole. The third patient relapsed with a recurrence of positive cultures during the seventh day of cefamandole therapy. Therefore, cefamandole does not appear to be a useful agent for treatment of meningitis due to H. influenzae type b irrespective of in vitro susceptibility or evidence of penetration into the cerebrospinal fluid.
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PMID:Failure of cefamandole in treatment of meningitis due to Haemophilus influenzae type b. 30 3

We have developed a new micro-broth-dilution assay for determining the antimicrobial susceptibility of Haemophilus influenzae. This assay is based on the ability of viable H. influenzae to reduce nitrates to nitrites. Bacterial viability is detected by a positive nitrite reaction rather than visible turbidity. The nitrate reduction assay was compared with a standard microassay using 51 isolates of H. influenzae and six beta-lactam antibiotics. Although there was good agreement between the two methods, the nitrate reduction assay was more sensitive in detecting viable bacteria, and so established a more accurate estimate of the minimal inhibitory concentration. The nitrate reduction assay offered the additional advantage that it could be used to determine the minimal bactericidal concentration without having to subculture the broth. Ampicillin, penicillin, and cefamandole were equally effective in vitro against susceptible strains (minimal inhibitory concentrations, 0.125 to 0.5 mug/ml), whereas all three antibiotics were ineffective against two beta-lactamase-producing strains. Using the nitrate reduction assay, resistance to cefamandole was detectable with inoculum sizes ranging from 10(4) to 10(6) colony-forming units per ml, while the turbidity assay detected resistance only with the largest inoculum.
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PMID:Nitrate reduction: new method for testing the antibiotic susceptibility of Haemophilus influenzae. 30 65

Sulfamethoxazole-trimethoprim and three oral cephalosporins, cefaclor, cephalexin, and cephradine, were evaluated in vitro as possible alternatives to chloramphenicol in the treatment of non-central nervous system infections due to ampicillin-resistant Haemophilus influenzae. Sixty-four isolates of H. influenzae, including 31 beta-lactamase-positive strains, were tested by the agar dilution method. All strains were inhibited by 0.78/0.039 mug sulfamethoxazole-trimethoprim per ml and by 0.78 mug of chloramphenicol per ml. At 6.25 mug/ml, 100, 11, and 3% of all strains were inhibited by cefaclor, cephalexin, and cephradine, respectively. Thus, on the basis of drug concentrations presumably achievable in serum, 100% of strains were susceptible to sulfamethoxazole-trimethoprim, chloramphenicol, and cefaclor. However, a considerable inoculum effect was noted with both beta-lactamase-positive and -negative strains, when tested with sulfamethoxazole-trimethoprim; the minimal inhibitory concentrations of cefaclor were only slightly affected. Also, synergistic effects of sulfamethoxazole-trimethoprim, sulfamethoxazole-erythromycin, and sulfamethoxazole-cefaclor were seen when combinations were tested against both beta-lactamase-positive and -negative strains, as determined by minimal inhibitory concentrations measured by the broth dilution method and by killing curve analyses. These results support further evaluation of these combinations and of cefaclor alone for the treatment of non-central nervous system infections due to H. influenzae.
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PMID:In vitro susceptibility of Haemophilus influenzae to sulfamethoxazole-trimethoprim and cefaclor, cephalexin, and cephradine. 30 67

The emergence of resistance to ampicillin and other antibiotics in Haemophilus influenzae has been a relatively recent event. In contrast, drug resistance has been rampant in the Enterobacteriaceae for many years. Ampicillin-resistance in H. influenzae is almost invariably attributable to possession of the TEM (Type III a)beta-lactamase. As is common in other bacteria the gene specifying this enzyme is plasmid-borne in Haemophilus. Some ampicillin-resistant strains of H. influenzae can transfer the TEM beta-lactamase gene to other strains of Haemophilus, to Escherichia coli and to Pseudomonas aeruginosa. The features of such transfer are unusual and lead for example, to the induction of adenine requirement in recipient strains of P. aeruginosa. Crypticity measurements of beta-lactamase activity show that in comparison to P. aeruginosa or E. coli, the outer membrane of H. influenzae affords only a weak penetration barrier to beta-lactam antibiotics. This may have consequences for the stability and distribution of beta-lactamase production in Haemophilus spp. which are discussed. A comparison of the molecular properties of R-plasmids determining a variety of resistances and carried by strains of H. influenzae isolated in diverse geographical locations has revealed unexpected homologies. A series of such plasmids of similar molecular weights (about 30 X 10(6)) differ substantially only in the transposable resistance genes that they carry. A model based on these findings is presented to explain the acquisition of ampicillin- and other resistances by Haemophilus.
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PMID:beta-lactamases and R-plasmids of Haemophilus influenzae. 30 59

We have studied cefuroxime, a new beta-lactamase resistant cephalosporin, and cefoxitin, the first cephamycin antibiotic, which is also resistant to many beta-lactamases. Both of these antibiotics have been shown to be microbiologically superior to the "first generation" cephalosporins, cefuroxime having notable activity against Haemophilus influenzae, and cefoxitin against Bacteroides fragilis. Neither antibiotic is absorbed from the gut but, following parenteral administration, serum, urine and bile concentrations are high. Clinical trials have been conducted on both cefoxitin and cefuroxime. The results of these have been satisfactory and untoward side-effects minimal. We suggest that cefoxitin will be particularly valuable in the management of abdominal sepsis and cefuroxime in infections caused by H. influenzae.
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PMID:Studies with cefuroxime and cefoxitin. 30 60

CP-45,899 {3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 4,4-dioxide, [2S-(2alpha,5alpha)]} is an irreversible inhibitor of several bacterial penicillinases and cephalosporinases. In the presence of low concentrations of CP-45,899, ampicillin and other beta-lactams readily inhibit the growth of a variety of resistant bacteria that contain beta-lactamases. CP-45,899 used alone displays only weak antibacterial activity, with the notable exception of its potent effects on susceptible and resistant strains of Neisseria gonorrhoeae. CP-45,899 appears to be somewhat less potent but markedly more stable (in aqueous solution) than the recently described beta-lactamase inhibitor clavulanic acid. The spectrum extensions provided by the two compounds are similar. A 1:1 mixture of CP-45,899 and ampicillin displays marked antimicrobial activity in mice experimentally infected with ampicillin-resistant Staphylococcus aureus, Haemophilus influenzae, Klebsiella pneumoniae, and Proteus vulgaris.
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PMID:CP-45,899, a beta-lactamase inhibitor that extends the antibacterial spectrum of beta-lactams: initial bacteriological characterization. 30 6

Clavulanic acid, Z-(2R,5R)-3-(beta-hydroxyethylidene)-7-oxo-4-oxa-1-azabicyclo-[3,2,0] heptane-2-carboxylic acid, has been shown to be an effective inhibitor of the beta-lactamases of the Richmond types II, III, IV, and V. Inhibition is a time-dependent reaction and is irreversible. Clavulanic acid had poor antibacterial activity against Staphylococcus aureus, Enterobacteriaceae, and Pseudomonas aeruginosa, with minimal inhibitory levels greater than 25 mug/ml. It did inhibit the majority of Neisseria gonorrhoeae at 0.1 mug/ml and Haemophilus influenzae at 6.3 mug/ml. Clavulanic acid acted synergistically with penicillins and cephalosporins to inhibit beta-lactamase-producing S. aureus and Enterobacteriaceae. Clavulanic acid combined with ampicillin inhibited beta-lactamase-producing N. gonorrhoeae, H. influenzae, Escherichia coli, Salmonella typhi, and Shigella sonnei.
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PMID:Clavulanic acid, a novel inhibitor of beta-lactamases. 31 Feb 79

Haemophilus influenzae is an aerobic pleomorphic gram-negative coccobacillus that requires both X and V factors for growth. It grows poorly, if at all, on ordinary blood agar unless streaked with Staph. aureus. It grows well on chocolate agar. Because this medium is often not used in culturing specimens from adults and because the organism may be overgrown by other bacteria, the frequency of H. influenzae infections has undoubtedly been seriously underestimated. This is aggravated by the failure of many physicians to obtain blood cultures in suspected bacterial infections and the failure of many laboratories to subculture them routinely onto chocolate agar. H. influenzae, along with Streptococcus pneumoniae, is a major factor in acute sinusitis. It is probably the most frequent etiologic agent of acute epiglottitis. It is probably a common, but commonly unrecognized, cause of bacterial pneumonia, where it has a distinctive appearance on Gram stain. It is unusual in adult meningitis, but should particularly be considered in alcoholics; in those with recent or remote head trauma, especially with cerebrospinal fluid rhinorrhea; in patients with splenectomies and those with primary or secondary hypogammaglobulinemia. It may rarely cause a wide variety of other infections in adults, including purulent pericarditis, endocarditis, septic arthritis, obstetrical and gynecologic infections, urinary and biliary tract infections, and cellulitis. Antimicrobial susceptibility testing is somewhat capricious in part from the marked effect of inoculum size in some circumstances. In vitro and in vivo results support the use of ampicillin, unless the organism produces beta-lactamase. Alternatives in minor infections include tetracycline, erythromycin, and sulfamethoxazole-trimethoprim. For serious infections chloramphenicol is the best choice if the organism is ampicillin-resistant or the patient is penicillin-allergic.
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PMID:Haemophilus influenzae infections in adults: report of nine cases and a review of the literature. 31 Sep 43


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