Studies on haemophilus influenzae; Haemophilus influenzae antigens studied by the gel precipitation method.
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Antigens↗
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Antimicrobial susceptibility of Haemophilus influenzae, Haemophilus parainfluenzae and Moraxella catarrhalis isolated from adult patients with respiratory tract infections in four southern European countries. The ARISE project.
Over a 7-month period in 2000-2001, 1213 Haemophilus influenzae, 112 Haemophilus parainfluenzae and 142 Moraxella catarrhalis isolates were recovered from adult patients with respiratory tract infections. Patients were from four southern European countries (Spain, Italy, Portugal and Greece). The antimicrobial susceptibility of the isolates to 11 antibiotics was determined in a central laboratory. The most active drugs on the basis of MICs were levofloxacin, cefditoren, cefotaxime, cefpodoxime and amoxicillin/clavulanate. MICs > or = 2 mg/l for amoxicillin were found in 19.5, 28.6, and 75.4% of H. influenzae, H. parainfluenzae and M. catarrhalis isolates, respectively. Isolates of H. influenzae and H. parainfluenzae with reduced susceptibility or that were fully resistant to amoxicillin/clavulanate, cefuroxime and clarithromycin were detected (0.2-1.8%) as well as M. catarrhalis resistant to clarithromycin (0.7%). Regular surveys of resistance patterns for antimicrobial agents are necessary.
Adult↗
The Italian Epidemiological Survey 1997-1999. Antimicrobial susceptibility data of Haemophilus influenzae, Haemophilus parainfluenzae and Moraxella catarrhalis in Italy.
The Italian Epidemiological Survey began a surveillance study with the aim of monitoring the antimicrobial resistance of respiratory pathogens. From 1997 to 1999, 2028 strains of Haemophilus influenzae and 523 strains of Haemophilus parainfluenzae were collected from 59 Clinical Microbiology Laboratories distributed throughout Italy. In 1998, the study was extended to include Moraxella catarrhalis and a total of 360 isolates were collected. There was a significant increase in the beta-lactamase production both for H. influenzae (from 5% in 1997 to 16% in 1999) and for H. parainfluenzae (from 5% in 1997 to 22% in 1999). Beta-lactamase production in M. catarrhalis was 84% in 1998 and 87% in 1999. Beta-lactamase production affected the susceptibility to unprotected penicillins (87% in H. influenzae, 85% in H. parainfluenzae and 34% in M. catarrhalis), and in part the susceptibility to cefaclor (about 98%). Amoxycillin/clavulanate, cefixime, ceftriaxone and ciprofloxacin were active against all strains of H. influenzae, H. parainfluenzae and M. catarrhalis.
Anti-Bacterial Agents↗
In vitro activity of a new broad-spectrum, beta-lactamase-stable oral cephalosporin, cefixime, in comparison with other drugs, against Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis and Streptococcus pneumoniae.
Cefixime, a new orally absorbed iminomethoxyaminothiazolyl cephalosporin, was tested against some microorganisms involved in upper and lower respiratory tract infections such as Haemophilus (influenzae and parainfluenzae), Moraxella catarrhalis and Streptococcus pneumoniae, isolated in the period from November 1990 to April 1991. Its activity was compared to nine other antimicrobial agents: erythromycin, trimethoprim-sulfamethoxazole, ampicillin, amoxicillin-clavulanate, cefaclor, ceftazidime, ceftriaxone, cefotaxime and ofloxacin. Cefixime inhibits 90% of S. pneumoniae, H. influenzae and H. parainfluenzae, both beta-lactamase producers (BLP) or not (NBLP) at concentrations of less than 0.25 mg/l. It inhibits 90% of M. catarrhalis (BLP and NBLP) at concentrations of less than 1 mg/l. In general, cefixime has a superior in vitro activity with respect to cefaclor and the other cephalosporins as well as erythromycin and amoxicillin (the last one in BLP strains). In the evaluation of the antibacterial activity of beta-lactam against Haemophilus and M. catarrhalis, the authors observed different indications in the guidelines for ampicillin. Cefixime is not destroyed by the plasmid-mediated beta-lactamase produced by Haemophilus sp. and M. catarrhalis (TEM and ROB in Haemophilus strains and BRO in M. catarrhalis). In view of its excellent in vitro activity against the commonly encountered respiratory tract pathogens, cefixime is indicated in the therapy of these infections.
Administration, Oral↗
The tympanic membrane and middle ear mucosa during non-typeable Haemophilus influenzae and Haemophilus influenzae type b acute otitis media: a study in the rat.
Non-typeable Haemophilus influenzae (NTHi) and encapsulated Haemophilus influenzae type b (Hib) were inoculated into the middle ears of Sprague-Dawley rats. Tympanic membrane (TM) status was assessed otomicroscopically and specimens from various middle ear areas were prepared for light microscopy at various times during the acute phase and up to 6 months after inoculation. Irrespective of bacteria strain, acute otitis media (AOM) was present in all ears 4 days after inoculation. The Hib-infected ears showed initially a severe course of AOM, but all were otomicroscopically resolved by day 12, at which time a few NTHi-inoculated ears still exhibited middle ear effusion. The TMs infected with Hib had normalized without scar formation, whereas NTHi induced a persistent thickening of the TMs in half of all cases. The middle ear mucosa of NTHi-infected ears initially showed vigorous activity among the goblet cells, but the mucosa normalized after the acute phase. Hib, by contrast, induced prominent changes in the middle ear mucosa. Initially, no goblet cell granules or ciliated cells could be observed in the mucosa. Later on, the epithelium contained large, active goblet cells. Glands appeared beneath the mucosa which persisted as streaks of epithelial cells throughout the study period. The findings show that NTHi and Hib both induce AOM but with differing clinical courses, and affect different targets in the middle ear.
Acute Disease↗
Oklahoma notes decline in Haemophilus influenzae: invasive Haemophilus influenzae disease among children aged < 5 years--Oklahoma, 1990-1997.
Haemophilus influenzae (Hi) causes many clinical illnesses such as meningitis, bacteremia, epiglottitis, pneumonia, otitis media, sinusitis and tracheobronchitis. Before the introduction of the Haemophilus influenzae type b (Hib) conjugate vaccine in 1988, Hib caused more than 95 percent of invasive Hi disease in developed countries. Conjugate vaccines were licensed for use in children > or = 15 months of age in 1989 and for use in children > or = 2 months of age in 1990. During 1987-1995, the incidence of invasive Hi disease among children < 5 years of age decreased 96 percent in the United States. This report summarizes the trend in invasive disease caused by Hi among Oklahoma children < 5 years of age. The data represents cases reported to the OSDH as part of the infectious disease surveillance system. Invasive Hi disease has been reportable by law in Oklahoma since 1983.
Child, Preschool↗
Haemophilus influenzae: then and now.
Haemophilus influenzae has long been recognised as a major cause of serious infection and mortality in children less than 5 years old. Prior to the introduction of Haemophilus influenzae type b (Hib) immunisation, the incidence of a child suffering an invasive Haemophilus infection was 20-50/100,000 in industrialised countries and up to ten times higher in developing regions. The introduction of a Hib vaccine programme results in a rapid and dramatic decline in the incidence of Hib infection in the susceptible childhood population. For example, within two years of the introduction of routine Hib vaccination of infants in the UK, the risk of serious Hib infection had fallen from 1:600 to 1:30,000 by 5 years of age. Many other European countries have introduced, or are in the process of introducing, a routine Hib immunisation programme. Because the epidemiology of Haemophilus influenzae infection is changing so dramatically, it is opportune to review Haemophilus influenzae as it was perceived in the pre-vaccine era (the past) and during vaccine implementation (the present), and how its role may change in the post-vaccination era (the future). This review will summarise the historical landmarks that have led to our present-day understanding of Haemophilus influenzae pathogenicity, the concerns about antibiotic resistance, the features of the host immune response to Haemophilus influenzae, and the introduction of the Hib vaccine. Furthermore, the possible importance of this organism in the future will be discussed.
Haemophilus Infections↗
Day care characteristics associated with Haemophilus influenzae disease. Haemophilus influenzae Study Group.
To identify characteristics of day care facilities associated with H. influenzae disease, we compared 92 licensed facilities in which a case of H. influenzae disease had occurred with randomly selected facilities at which no cases occurred. Matched univariate analysis showed that personnel at facilities where H. influenzae disease occurred were more likely than those at control facilities to use towels or handkerchiefs to wipe children's noses, admit children who were not toilet trained or had diarrhea ("liberal fecal policy"), had a narrower age range, were more likely than control facilities to be for-profit and less likely to use volunteers. In a multivariate model that adjusted for age range, profit status and liberal fecal policy, towel or handkerchief use (OR 5.5, 95% CI: 1.1, 30) was the only variable independently associated with case facilities. This is the first association of a specific day care practice with H. influenzae disease.
Analysis of Variance↗
Interpretive criteria for CI-960, fleroxacin and temafloxacin susceptibility tests with Haemophilus influenzae.
Haemophilus influenzae strains with varied ampicillin resistance and beta-lactamase production patterns were tested against three investigational fluorinated quinolones (CI-960, fleroxacin, temafloxacin) using Haemophilus Test Medium (HTM) and National Committee for Clinical Laboratory Standards (NCCLS) methods. The disk diffusion zones and MICs were compared and regression statistics and scattergrams generated. The rank order of the agents according to activity against Haemophilus influenzae was CI-960 (MIC50 0.002 microgram/ml) greater than temafloxacin (MIC50 0.015 microgram/ml) greater than fleroxacin (MIC50 0.03 microgram/ml). The recommended susceptibility interpretive criteria for the 5-micrograms disks of each drug were: for CI-960 greater than or equal to 23 mm (MIC correlate less than or equal to 1 microgram/ml); for fleroxacin greater than or equal to 19 mm (MIC correlate less than or equal to 2 micrograms/ml); and for temafloxacin greater than or equal to 16 mm (MIC correlate less than or equal to 2 micrograms/ml). All recent Haemophilus influenzae isolates tested were susceptible to these potent fluoroquinolones and no interpretive errors were observed.
Anti-Infective Agents↗
Revised disk diffusion interpretive criteria for cefaclor, loracarbef, cefprozil and cefixime when testing Haemophilus influenzae on haemophilus test medium.
The aim of the current five-center collaborative study was to reassess the interpretive criteria for cefaclor, loracarbef, cefprozil and cefixime previously adopted or proposed by the National Committee for Clinical Laboratory Standards (NCCLS) for disk diffusion susceptibility tests with Haemophilus influenzae on Haemophilus Test Medium (HTM) agar. MICs and zones of inhibition were determined using NCCLS methods, HTM and two collections of strains of Haemophilus influenzae. One group of strains consisted of 118 stock organisms taken largely from various recent U.S. antibiotic resistance surveillance studies. The emphasis in this selected group of organisms was on strains that were beta-lactamase negative but ampicillin resistant (BLNAR) by some other mechanism. The second collection of test organisms consisted of 50 recent clinical isolates of Haemophilus influenzae obtained from each of the five participating study centers. This group was considered representative of the type of Haemophilus influenzae currently recovered from clinical sources in the USA. Frequency distribution assessment and error-rate bounded analysis of scattergram comparisons of MICs and zone sizes were used to develop the following zone diameters interpretive for disk diffusion susceptibility tests with Haemophilus influenzae on HTM agar: cefaclor, > or = 20 mm (susceptible, S) and < or = 16 mm (resistant, R); loracarbef, > or = 19 mm (S) and < or = 15 mm (R); and cefprozil, > 18 mm (S) and < 14 mm (R). The respective MIC correlates for all three antimicrobial agents were < or = 8 micrograms/ml (S) and 32 micrograms/ml (R).(ABSTRACT TRUNCATED AT 250 WORDS)
Cefaclor↗
Evaluation of a selective medium for the isolation and differentiation of Haemophilus influenzae and Haemophilus parainfluenzae from the respiratory tract of chronic bronchitics.
Respiratory tract specimens from chronic bronchitic patients were cultured for Haemophilus species on conventional chocolate agar and a modified sucrose medium in order to determine the accuracy of the new medium in differentiating Haemophilus influenzae from Haemophilus parainfluenzae strains. Haemophilus influenzae biotypes II and III and Haemophilus parainfluenzae biotypes I and II were found to be the predominant strains isolated from the respiratory tract. The modified sucrose medium was found to be a rapid and reliable means of differentiating Haemophilus influenzae from Haemophilus parainfluenzae by sucrose fermentation, on initial isolation.
Bronchitis↗
Involvement of HxuC outer membrane protein in utilization of hemoglobin by Haemophilus influenzae.
Haemophilus influenzae can utilize different protein-bound forms of heme for growth in vitro. A previous study from this laboratory indicated that nontypeable Haemophilus influenzae (NTHI) strain N182 expressed three outer membrane proteins, designated HgbA, HgbB, and HgbC, that bound hemoglobin or hemoglobin-haptoglobin and were encoded by open reading frames (ORFs) that contained a CCAA nucleotide repeat. Testing of mutants expressing the HgbA, HgbB, and HgbC proteins individually revealed that expression of any one of these proteins was sufficient to allow wild-type growth with hemoglobin. In contrast, mutants that expressed only HgbA or HgbC grew significantly better with hemoglobin-haptoglobin than did a mutant expressing only HgbB. Construction of an isogenic hgbA hgbB hgbC mutant revealed that the absence of these three gene products did not affect the ability of NTHI N182 to utilize hemoglobin as a source of heme, although this mutant was severely impaired in its ability to utilize hemoglobin-haptoglobin. The introduction of a tonB mutation into this triple mutant eliminated its ability to utilize hemoglobin, indicating that the pathway for hemoglobin utilization in the absence of HgbA, HgbB, and HgbC involved a TonB-dependent process. Inactivation in this triple mutant of the hxuC gene, which encodes a predicted TonB-dependent outer membrane protein previously shown to be involved in the utilization of free heme, resulted in loss of the ability to utilize hemoglobin. The results of this study reinforce the redundant nature of the heme acquisition systems expressed by H. influenzae.
Bacterial Proteins↗
Roxithromycin alone and in combination with sulphamethoxazole against Haemophilus influenzae.
Haemophilus influenzae is only moderately susceptible to erythromycin but previous studies in vitro and in vivo have shown that it is fully susceptible when erythromycin is combined with sulphonamides. The purpose of this study was to evaluate whether the activity of the new macrolide antibiotic roxithromycin was improved after combination with sulphamethoxazole. One hundred and eighty fresh clinical isolates of Haemophilus influenzae, comprising 74 ampicillin-susceptible, beta-lactamase negative, and 106 ampicillin-resistant, beta-lactamase positive, strains, were tested for their susceptibility to erythromycin, roxithromycin, sulphamethoxazole, erythromycin-sulphamethoxazole and roxithromycin-sulphamethoxazole in a fixed ratio of 1:19. Bacteriostatic and bactericidal synergy was found between roxithromycin and sulphamethoxazole more commonly than between erythromycin and sulphamethoxazole. Antagonism, was less common between roxithromycin and sulphamethoxazole than erythromycin and sulphamethoxazole. These results suggest that the in-vitro activity of roxithromycin is improved by combination with sulphamethoxazole, making this combination more attractive in the oral therapy of infections due to H. influenzae.
Culture Media↗
Identification of a haem-utilization protein (Hup) in Haemophilus influenzae.
Haemophilus influenzae has an absolute growth requirement for a porphyrin source. This growth requirement can be satisfied in vitro by haem, haemoglobin or the haemoglobin-haptoglobin, haem-haemopexin and haem-albumin complexes. A family of proteins, termed the Hgp proteins, which are essential for utilization of the haemoglobin-haptoglobin complex, has previously been identified. A strain lacking the Hgp proteins also has a residual ability to utilize haemoglobin, indicating that additional moieties contribute to haemoglobin utilization. Using a haemoglobin affinity method an approximately 105 kDa protein was isolated. Mutation of the identified gene in an Hgp null background reduced the ability of the mutant strain to utilize haemoglobin in vitro. The mutation also resulted in a reduced ability to utilize haem, haem-haemopexin, haem-albumin and haemoglobin-haptoglobin, thus identifying a general haem-utilization protein (Hup) in Haemophilus influenzae.
Amino Acid Sequence↗
Deoxyribonucleic acid relatedness between Haemophilus aegyptius and Haemophilus influenzae.
Haemophilus aegyptius should be considered a junior subjective synonym of Haemophilus influenzae. Both nomenspecies are indistinguishable by DNA/DNA hybridization (S1 nuclease method). No single phenotypic test can unambigously separate H. aegyptius from the other biotypes of H. influenzae.
DNA, Bacterial↗
DNA-binding vesicles released from the surface of a competence-deficient mutant of Haemophilus influenzae.
Haemophilus influenzae com-51, a mutant deficient in DNA uptake, produces an extracellular DNA-binding activity. The activity was specific for Haemophilus DNA and was isolated from cell-free competence medium after incubation for 100 to 130 min. Initial steps in the purification procedure resulted in the loss of detectable binding activity, but activity was restored by the addition of a nonionic detergent. The active fractions contained vesicles derived from the outer membrane of the cells. The vesicles were produced only under conditions that normally lead to competence development. The lack of competence of com-51 cells was not due to loss of protein synthesis in M-IV competence medium or to competition of extracellular protein for exogenous DNA. Results suggest that the inability of cells to bind DNA was due in part to the loss of DNA receptors that are released into the medium in membrane fragments.
Bacterial Proteins↗
Relationship between the specificity of IgA proteases and serotypes in Haemophilus influenzae.
Haemophilus influenzae is one of five bacterial species known to produce IgA proteases, enzymes that specifically cleave the human IgA1 heavy chain. Strains of H. influenzae produce three distinct types of IgA proteases that cleave different peptide bonds within the IgA1 hinge region. Type 1 protease cleaves the prolyl-seryl bond at position 231-232; type 2 protease cleaves the prolyl-threonyl bond at position 235-236, the same bond attacked by Neisseria gonorrhoeae and Neisseria meningitidis type 2 proteases. Type 3 protease yields a unique double Fd cleavage pattern; the exact peptide bonds cleaved have not been determined. The type of protease produced correlates with the serotype, but not with the biotype, of the isolate; serotypes A, B, D, and F produce primarily type 1 protease, whereas serotypes C and E produce only type 2 enzyme. Each nontypable strain yields one of the three protease types. These data further extend our knowledge of the extreme specificity of the IgA proteases and suggest that IgA protease type may be useful in the taxonomy and epidemiology of H. influenzae.
Chemical Phenomena↗
Two-dimensional map of basic proteins of Haemophilus influenzae.
Haemophilus influenzae is a bacterium of medical interest of which the entire genome has been sequenced. The proteome of the microorganism has been analyzed by two-dimensional gel electrophoresis, during which immobilized pH 3-10 gradient strips were used and approximately 300 proteins were identified. In order to detect additional, basic proteins, we analyzed the soluble protein fraction of H. influenzae and the proteins of fractions collected from affinity chromatography on heparin, by two-dimensional gel electrophoresis, using for the first-dimensional separation immobilized pH gradient strips comprising the pH region of 6-11. The protein spots were analyzed by matrix-assisted laser desorption ionization-mass spectrometry. One hundred and two proteins were identified, of which 58 were identified for the first time. A large percentage of the basic proteins represent nucleic acid binding and, in particular, ribosomal proteins. The locations of the identified basic proteins of H. influenzae are indicated in a two-dimensional map.
Bacterial Proteins↗