A taxonomic study of the genus Haemophilus, with the proposal of a new species

Reinvestigation and reclassification of a collection of 56 human isolates of Pasteurellaceae

Incorrect diagnosis of species belonging to the family Pasteurellaceae Pohl 1981 is often due to inadequate laboratory identification techniques. Reinvestigations of 56 human isolates of Pasteurellaceae and comparison of the results obtained with those obtained from nine reference strains in 65 different tests allowed classification of 26 strains as P. multocida ssp. multocida, 11 strains as P. multocida ssp. septica, 12 strains as P. canis, 4 strains as P. dagmatis and 1 strain as P. stomatitis. Two strains were tentatively classified with P. haemolytica biogroup 2(T) and the SP-group, respectively. The present investigation also showed that the type strains of P. gallinarum and Haemophilus aphrophilus were phenotypically related. Members of the family Pasteurellacea Pohl 1981 should be considered as potential etiologic agents of any local infection following animal bites or scratches.

Relationships among isolates of oral haemophili as determined by DNA-DNA hybridization

In order to assess the relationships among strains of the genera Actinobacillus and Haemophilus, DNAs from 50 strains of these genera were isolated and purified. The guanine plus cytosine (G + C) content of DNAs from strains of Haemophilus segnis and Haemophilus parainfluenzae were determined by thermal denaturation. DNA-DNA homologies were measured using labelled probes from one strain representing Haemophilus segnis (strain ATCC 10977), and two strains representing Haemophilus parainfluenzae (strains ATCC 9796 and ATCC 7901). Strains isolated as H. segnis had a G + C content of 39.0 to 42.9% and were 49-92% homologous with the ATCC 10977 DNA probe. All of the strains freshly isolated as H. parainfluenzae were 70-81% homologous with the ATCC 9796 DNA probe and had a G + C content of 34.9 to 38.3%. Strain ATCC 7901 was 11% homologous with the ATCC 9796 DNA probe, had a G + C content of 42.4%, and was 65-78% homologous to DNA from strains identified as Haemophilus aphrophilus and Haemophilus paraphrophilus. From these results we conclude that strain ATCC 7901 is a mislabelled strain of H. paraphrophilus. The results of multiple DNA-DNA hybridizations indicated that separate species designations were appropriate for H. segnis, H. parainfluenzae, Actinobacillus actinomycetemcomitans ("Haemophilus actinomycetemcomitans"), and H. aphrophilus. H. aphrophilus and H. paraphrophilus were closely related organisms and did not fulfill the generally accepted criteria for designation as separate species.

Antibiotic susceptibility of Haemophilus influenzae isolated from cerebrospinal fluid and blood

The emergence of ampicillin and chloramphenicol resistant Haemophilus influenzae type b in Denmark has created demands for alternative treatments of serious infections with H. influenzae. In this study 102 strains of H. influenzae recovered from cerebrospinal fluid (85) and blood (17) were tested for susceptibility to ampicillin, piperacillin, erythromycin, rifampicin, chloramphenicol, cefuroxime, cefotaxime, ceftazidime, ceftriaxone, moxalactam, aztreonam, and netilmicin by means of the agar dilution method. The majority (97%) was H. influenzae type b and of these strains 94% belonged to biotype I. Nine of the investigated strains were beta-lactamase producers. Ceftriaxone and cefotaxime were the most active agents (MIC90 less than or equal to 0.025 microliter/ml) followed by moxalactam and aztreonam (MIC90 = 0.1 microgram/ml). Except for ampicillin and piperacillin, the MIC was similar for beta-lactamase producers and non-producers. Several of the investigated antibiotics, especially some of the third generation cephalosporins, might constitute valid therapeutical alternatives to conventional drugs in the treatment of severe H. influenzae infections.

Genetic relationships of serologically nontypable and serotype b strains of Haemophilus influenzae

A collection of 242 strains of Haemophilus influenzae, including 65 nontypable (unencapsulated) isolates and 177 encapsulated serotype b isolates recovered largely from children with invasive and noninvasive diseases in the United States, was characterized by the electrophoretic mobilities of 15 metabolic enzymes presumably encoded by chromosomal genes. All enzymes were polymorphic for three to seven electromorphs, and 94 distinctive multilocus genotypes (electrophoretic types [ETs]) were distinguished, among which mean genetic (allelic) diversity was 0.500. Isolates recovered from cases of invasive or noninvasive diseases did not differ significantly in level of genetic variation. The observation that 29 ETs were represented exclusively by serotype b isolates and that each of the 65 nontypable isolates was of a unique ET strongly confirmed the hypothesis that unencapsulated clinical isolates are not merely phenotypic variants of the common serotype b cell lines. Rather, the two types of isolates are distinctive subsets of the multilocus chromosomal genotypes of the species as a whole. Serotype b capsule occurred in three groups of isolates that are distantly related in multilocus enzyme genotype. Isolates of four closely related nontypable biotype IV ETs associated with obstetrical infections or neonatal bacteremia were highly divergent from all others examined and may be specifically distinct. A phylogenetic scenario was proposed in which the ancestor of H. influenzae was encapsulated and the nontypable clones arose by convergent evolutionary loss of the ability to synthesize or extracellularly express a polysaccharide capsule.

Comparison of a new commercially prepared porphyrin test and the conventional satellite test for the identification of Haemophilus species that require the X factor

A test with a commercially developed porphyrin test agar was examined for the identification of Haemophilus spp. The porphyrin test agar method was compared with the conventional paper strip satellite method in tests with 187 isolates and was found to be easier to perform and interpret, giving a sensitivity of 98.7% and specificity of 94.7%.

A comparative study of amoxycillin and pivampicillin in persistent Haemophilus influenzae infection of the lower respiratory tract in children with chronic lung disease

A double-blind cross-over study was undertaken to compare the efficacy of amoxycillin and pivampicillin on Haemophilus influenzae infection of the lower respiratory tract in children. 20 patients with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD) due to other causes were included in the study. All patients had a history of regularly harbouring H. influenzae in sputum and repeated treatment failures with pivampicillin. 18 completed two 14-day courses in random order with equimolar doses of pivampicillin (80 mg/kg/day) and amoxycillin (62 mg/kg/day). Both drugs were well tolerated with no serious side effects, but pivampicillin was associated with more pronounced nausea. In steady state the mean serum concentrations of antibiotics 2 and 4 h after medication were 9.7 and 3.7 micrograms/ml for pivampicillin and 19.1 and 7.9 micrograms/ml for amoxycillin (p less than 0.01). Eradication of H. influenzae and clinical improvement was seen in one-third of the courses with both drugs. Betalactamase producing ampicillin-resistant strains emerged during 58% of the amoxycillin courses, but only in 16% of the pivampicillin courses (p less than 0.001). The high number of treatment failures and the development of resistant strains indicate that betalactamase inhibitors may possibly improve the efficacy of these drugs, especially of amoxycillin, in these patients.

Characterization of Haemophilus spp. isolated from healthy swine and evaluation of cross-reactivity of complement-fixing antibodies to Haemophilus pleuropneumoniae and Haemophilus taxon "minor group"

Of 30 sows from a herd believed to be free of Haemophilus pleuropneumoniae infection, 2 had complement-fixing antibodies to H. pleuropneumoniae serotype 5. Necropsy and microbiological examination of the two sows revealed no evidence of H. pleuropneumoniae infection; however, Haemophilus taxon "minor group" and a urease-negative, indole-positive Haemophilus sp. were isolated from numerous respiratory tract sites in both sows. Isolation of these Haemophilus spp. was facilitated by serially diluting specimens in two broth media. Pigs from a closed, respiratory disease-free herd were inoculated with four strains of Haemophilus taxon "minor group" to determine whether the organism induces antibodies which cross-react with H. pleuropneumoniae in the complement fixation test. Antigenic heterogeneity among the taxon "minor group" strains was apparent; however, antibodies cross-reacting between these strains and H. pleuropneumoniae serotypes 1 through 5 and 7 were not detected.

Comparison of outer membrane protein and biochemical profiles of Haemophilus aegyptius and Haemophilus influenzae biotype III

Haemophilus aegyptius and Haemophilus influenzae biotype III are morphologically and biochemically similar; however, their outer membrane protein (Sarkosyl insoluble) profiles are distinct. Of 18 strains of H. aegyptius examined, 15 had a type 1 protein profile, and 3 had a type 2 profile, whereas the 5 strains of H. influenzae biotype III examined had three other protein profile types. All Haemophilus strains examined had 31- and 76-kilodalton (kDa) proteins and minor proteins with molecular masses between 20 and 100 kDa. H. aegyptius, with a type 1 protein profile, had major outer membrane proteins with apparent molecular masses of 27, 35.5, and 41.5 kDa, and H. aegyptius, with a type 2 protein profile, had 26-, 29-, 39.5-, and 41-kDa proteins. The type strain of H. influenzae biotype III had three major outer membrane proteins with apparent molecular masses of 29, 38.5 and 40 kDa. Four other strains designated as H. influenzae biotype III had major outer membrane proteins between 27 and 41.5 kDa representing two additional protein profiles.

A population genetic framework for the study of invasive diseases caused by serotype b strains of Haemophilus influenzae

One hundred seventy-seven isolates of serotype b Haemophilus influenzae recovered largely from children with invasive disease in the United States were characterized by the electrophoretic mobilities of 16 metabolic enzymes, the NaDodSO4/PAGE pattern of outer-membrane proteins (OMP), and biotype. Thirty-two distinctive multilocus genotypes (electrophoretic types, ETs) were distinguished on the basis of allele profiles at the enzyme loci. Twenty-eight OMP types and five biotypes were identified, but only 55 distinctive combinations of ET, OMP type, and biotype were represented. The strong nonrandom associations of characters and the recovery of isolates with identical properties in widely separated geographic regions and over a 40-year period suggest that the population structure of H. influenzae is basically clonal. Examination of nonserotype b isolates indicated that clones of serotype b are a restricted subset of the genotypes in the species as a whole. Currently, most of the invasive H. influenzae disease in the United States is caused by serotype b strains of two related ETs, and, more specifically, much of it is attributable to two subclones marked by OMP type. There is evidence that the frequency of the ET-1/OMP 1H/biotype I subclone has increased dramatically in the United States since the 1939-1954 period. The hypothesis that populations of H. influenzae are subject to marked temporal variation in clonal composition is supported by evidence of major differences in the genetic structure of populations in the United States and the Netherlands.

Tolerance of Haemophilus influenzae to beta-lactam antibiotics

Two hundred clinical isolates of Haemophilus influenzae were tested for tolerance (MBC/MIC greater than or equal to 32) to ampicillin and cefotaxime by broth dilution tests. Of 200 strains, 9 were tolerant to ampicillin, and 10 were tolerant to cefotaxime. Tolerant organisms were identified in both systemic and nonsystemic infections and among different biotypes and serotypes of H. influenzae. These tolerant isolates were compared with nontolerant isolates by broth dilution and killing curves with log-phase and stationary-phase inocula. Both tolerant and nontolerant bacteria in log phase were killed more rapidly by antibiotics than bacteria in stationary-phase growth. When tested against 11 different beta-lactams, several patterns of tolerance were observed. Six of the ten strains were tolerant to aztreonam, four were tolerant to cefuroxime, three were tolerant to cefamandole, and two were tolerant to cefoxitin. Strain H130 was tolerant to all beta-lactam antibiotics studied. None of the 10 tolerant H. influenzae isolates were tolerant to chloramphenicol, rifampin, tobramycin, ciprofloxacin, enoxacin, and trimethoprim-sulfamethoxazole. Although the clinical significance of tolerance is not determined, this study suggests that the bactericidal activity (MBC) of beta-lactam antibiotics against H. influenzae should be determined in cases of severe infections in which clinical response is slow or unsatisfactory.

Meningitis and brain abscess due to Haemophilus paraphrophilus

A case of meningitis and brain abscess due to Haemophilus paraphrophilus in a patient with congenital heart disease is reported. The abscess communicated with the cerebral ventricular system. Although the infecting strain was found to be highly sensitive to ampicillin, the patient died despite appropriate antimicrobial therapy. Characteristics distinguishing Haemophilus paraphrophilus and related species are discussed.

The microbial aetiology of genital ulcers in black men in Durban, South Africa

The microbial aetiology of genital ulcers was assessed in 100 black men attending a sexually transmitted disease (STD) clinic in Durban, South Africa. Forty patients harboured Haemophilus ducreyi, one hepes simplex virus, and one Neisseria gonorrhoeae. Syphilis was diagnosed in 44 patients on the basis of dark field microscopy or positive syphilis serology test results, or both. Of these 44 patients, eight also harboured N ducreyi, one herpes simplex virus. Lymphogranuloma venereum was diagnosed in one patient. No cause of ulceration could be found in the remaining 16 patients.

Plasmid-mediated aminoglycoside phosphotransferases in Haemophilus ducreyi

Three clinical isolates of Haemophilus ducreyi, representing at least two subtypes, were shown to be resistant to streptomycin and kanamycin. They also produced a beta-lactamase and chloramphenicol acetyltransferase and were resistant to tetracycline. In the three strains the resistance to both aminoglycoside antibiotics was encoded by a plasmid of ca. 4.7 kilobases which apparently did not carry ampicillin, chloramphenicol, or tetracycline resistance genes, as determined after transfer to Escherichia coli by transformation. Resistance to streptomycin and kanamycin was due to the presence of two aminoglycoside phosphotransferases (APH). The enzyme modifying kanamycin was a 3',5"-APH of type I [APH(3',5")-I], as inferred from its substrate profile and immunological cross-reactivity with the APH(3',5")-I encoded by the transposable element Tn903. However, the APH(3',5")-I gene in H. ducreyi did not appear to be carried by Tn903.

Differentiation between major species of the Actinobacillus--Haemophilus--Pasteurella group by gas chromatography of trifluoroacetic acid anhydride derivatives from whole-cell methanolysates

A method based on whole-cell methanolysis and trifluoroacetic acid anhydride derivatization was developed for routine laboratory differentiation between isolates from the Actinobacillus--Haemophilus--Pasteurella group. All species, except Haemophilus aphrophilus, contained D-glycero-D-mannoheptose, although in varying concentrations. The distribution of this sugar could be used to distinguish H. aphrophilus from Actinobacillus actinomycetemcomitans, H. paraphrophilus, H. influenzae type b, Pasteurella haemolytica, P. multocida and P. ureae, and also H. influenzae type b from Pasteurellae. The pattern of major sugars in P. ureae and P. haemolytica resembled that of A. actinomycetemcomitans. Major fatty acids of the whole-cell methanolysates provided no basis of interspecies differentiation.

[Enzymatic profile and plasmid content of Neisseria polysacchareae]

The enzymatic profile of "Neisseria polysacchareae" was determined by using chromogenic substrate (API System), and was compared to that of N. meningitidis, N. gonorrhoeae and N. lactamica. The tested classes of enzymes were aminopeptidase, proteases, esterases, lipases, glycosidases, phosphatase and phosphoamidase. "N. polysacchareae" exhibited various aminopeptidase and protease activities and a strong esterase activity. No lipase and glycosidase activities were detected by the tested substrates. The strains of "N. polysacchareae" differed from that of N. meningitidis in the presence of hydroxyproline aminopeptidase and the lack of gamma-glutamyl-transferase activity. Five strains harboured extrachromosomal elements. The plasmids were of 4.2 Kb in size in four cases and of more than 40 Kb in four cases. Three strains simultaneously harboured these two plasmids. This plasmid content is another characteristic of strains of this new taxon. No phenotypic modification was observed in plasmid-containing strains.

Frequency and properties of naturally occurring adherent piliated strains of Haemophilus influenzae type b

We found that 41 of 75 (55%) children with Haemophilus influenzae type b disease (70 cases of meningitis, 2 of cellulitis, 2 of septic arthritis, and 1 of epiglottitis) and 2 of 120 (1.7%) children with upper respiratory infection were colonized with H. influenzae type b in the nasopharynx (NP). Of these 43 NP strains from children with systemic H. influenzae type b disease, 7 (16%) adhered to human buccal epithelial cells. The strains isolated from the systemic site of all children, including children from whose NP adherent bacteria were isolated, did not adhere to buccal epithelial cells in vitro. Each adherent NP strain had biotype (I), serotype (b), and antibiotic susceptibility (sensitive) similar to that of the corresponding nonadherent systemic isolate. With one exception, all NP-systemic pairs had similar major outer membrane proteins. Six of the seven NP strains had a protein band in the whole cell lysate preparation with a molecular weight between 22,000 and 23,000, which could not be seen in the nonadherent cerebrospinal fluid strains. Electron micrographs of all adherent strains showed that more than 95% of the organisms examined were highly piliated, whereas the nonadherent strains were not piliated. All piliated strains agglutinated human erythrocytes. Adherence to buccal epithelial cells and agglutination of erythrocytes could not be blocked by mannose or alpha-methyl-D-mannoside. We speculate that piliation is not important for NP colonization by H. influenzae type b and that the loss of pili may be required for host invasion.

Distribution of biotypes of Haemophilus influenzae and H parainfluenzae in patients with cystic fibrosis

One hundred and eighty eight isolates of Haemophilus influenzae and 187 isolates of H parainfluenzae from patients with cystic fibrosis, patients with respiratory infections but without cystic fibrosis, and patients with neither cystic fibrosis nor respiratory infections were biotyped. Biotype I of H influenzae were found significantly more often in patients with cystic fibrosis compared with those with normal respiratory tracts. On the other hand, biotype II strains of H influenzae were found less often in the cystic fibrosis group. Half of the biotype V strains produced beta-lactamase.

Subtyping of Danish Haemophilus influenzae type B by their 45000 and 46000 molecular weight proteins

In order to obtain a way of subtyping Haemophilus influenzae type b strains, outer-membrane protein patterns were investigated. Outer-membrane proteins from 45 different Haemophilus influenzae type b strains were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The non-heated sarkosyl insoluble outer-membrane preparations all contained four major proteins with molecular weights (Mr) of 39,000, 33,000, 30,000, and 28,000, except for one strain which possessed a protein weighing approximately 32,000. After heating the samples a 45,000 Mr protein appeared in 43 of the strains, and a 46,000 Mr in two. The 39,000 Mr protein remained unchanged, whereas the 33,000 Mr protein disappeared. The 30,000 and the 28,000 Mr proteins became more clearly separated. A faint 16,000 Mr band was observed in both heated and non-heated samples. 42 strains with the light heat-modified protein band had identical protein patterns and could not be subdivided by the methods used and may therefore constitute a clone. The remaining strains had individual patterns.

Haemophilus ducreyi

Haemophilus ducreyi is the etiologic agent of chancroid, an infection which is endemic in tropical and subtropical areas of the world and which is becoming more prevalent in Europe and North America. Recently, several strains have demonstrated resistance to several antimicrobials by plasmid acquisition and cell envelope alteration making control of the spread of this organism a challenge. Equally challenging is the growth of this organism in the clinical microbiology laboratory because of its in vitro fastidious nature. Currently, the therapy of choice for Haemophilus ducreyi infection is trimethoprim sulfamethoxazole or erythromycin. Plasmid enumeration and restriction endonuclease fingerprinting in addition to outer membrane protein profiles may provide a basis for subtyping which would be useful in epidemiologic studies.

Typing Haemophilus ducreyi by indirect immunofluorescence assay

Rabbits were inoculated with untreated whole cells of 16 strains of Haemophilus ducreyi. Homologous titres in an indirect immunofluorescence test ranged from 1/320 to 1/1280. No cross reactions, or very few, were observed between antisera to these strains and 22 other (possible taxonomically related) species, strains, and genera. A large diversity in types of antigen was observed among the strains of H ducreyi. Antiserum from two antigens (35000 and 3138), however, reacted with all 16 H ducreyi antigens tested. At least nine of the strains of H ducreyi examined could be identified as determining the type of antigen.

Bacteremia due to nontypable Haemophilus influenzae--three cases in a community hospital

Nontypable Haemophilus influenzae is a normal inhabitant of the upper respiratory tract and a common pathogen in diseases limited to mucosal surfaces. Nontypable H. influenzae has only occasionally been reported to cause invasive disease locally or systemically. In a period of two years, three patients of 17 with positive blood cultures for H. influenzae were found to have nontypable strains, two of which were resistant to ampicillin. The presumed sites of entry were an oral mucosal lesion, sinus mucosa, and female genital tract. All three patients responded rapidly to antibiotics to which their isolates were susceptible.

Biotypes of serologically nontypable Haemophilus influenzae isolated from the middle ears and nasopharynges of patients with otitis media with effusion

A biotype analysis was performed on serologically nontypable Haemophilus influenzae isolates from the middle ear effusions and nasopharynges of 33 children with chronic otitis media with effusion (serous otitis media). Over 50% of the H. influenzae isolates from the middle ears belonged to biotype II. The incidence of beta-lactamase production was 17%. The results of this study indicate that future clinical or experimental investigations of chronic otitis media with effusion induced by serologically nontypable H. influenzae should focus on this clinically important biotype.

Characterization of Haemophilus influenzae type b fimbriae

We confirmed that the fimbriae of Haemophilus influenzae type b conferred hemagglutinating activity (HA) towards human erythrocytes, and erythrocytes of certain other species. Most (17/25) cerebrospinal fluid isolates lacked detectable HA on direct testing, but selective enrichment for fimbriation (f+) indicated that 22 of 25 strains could produce these surface structures. HA was unchanged from pH 4.5 to 9.5 and was not inhibited by mannose or certain other simple sugars. The HA titer of a suspension of three f+ strains was slightly decreased at 50 degrees C; HA was lost by heating at 60 degrees C for 3 min. Growth on a variety of solid and liquid media and under differing degrees of oxygenation did not change the HA titer of a suspension of three f+ strains. Fimbriation was not lost on repeated subculture. Wild-type fimbriated strains, and those derived by transformation, did not contain detectable plasmid DNA. Transformation of a strain lacking fimbriae to f+ was associated with the appearance of an outer membrane protein of 24 kilodaltons. This protein was purified from one strain to homogeneity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis by selective detergent solubilization and ammonium sulfate fractionation. Colonization capacity was equivalent with an isogenic untypable strain lacking or possessing fimbriae. Fimbriae of type b H. influenzae possess characteristics similar to those structures on other gram-negative bacteria; their role in cell physiology or pathogenesis of invasive disease is unknown.

Detection of beta-glucuronidase in lactose-fermenting members of the family Enterobacteriaceae and its presence in bacterial urine cultures

Four hundred strains of lactose-fermenting Enterobacteriaceae were tested for hydrolysis of p-nitrophenyl-beta-D-glucopyranosiduronic acid, the chromogenic enzyme substrate of beta-glucuronidase. Escherichia coli was found to be homogeneous with respect to beta-glucuronidase: more than 94% of the examined E. coli strains were positive, whereas none of the other lactose-fermenting strains possessed beta-glucuronidase activity. The qualitative beta-glucuronidase test, as rapid and simple as the o-nitrophenyl-beta-D-galactopyranosidase test, proved to be of diagnostic value, especially in the identification of E. coli in primary urine cultures. No significant differences were observed in the results of experiments in which either substrate-impregnated disks prepared in the laboratory or commercially available tablets were used.

Microbial causes of neonatal conjunctivitis

We assessed the microbial causes of neonatal conjunctivitis by comparing 55 infants with purulent conjunctivitis and 60 healthy control infants. A mean of greater than 5 leukocytes per 1000X microscopic field was seen in Gram-stained smears obtained from the more inflamed eye in 77% of 30 untreated patients but none of 57 controls. Pathogens isolated more often from untreated patients than from controls included Haemophilus spp. (17% vs 2%, P = 0.01), Staphylococcus aureus (17% vs 2%, P = 0.01), Chlamydia trachomatis (14% vs 0%, P = 0.01), enterococci (8% vs 0%, P = 0.05), and Streptococcus pneumoniae (11% vs 2%, P = 0.06). One or more of these pathogens were isolated from the conjunctivae in 58% of patients and 5% of controls (P less than 0.001). Bacterial morphology seen on smear correlated with the pathogens cultured. Isolation of Haemophilus spp. or S. pneumoniae was associated with dacryostenosis. We conclude that several microbial pathogens are implicated in neonatal conjunctivitis. These organisms have differing susceptibilities to antimicrobial agents, so culture and sensitivity testing are required as a guide to therapy.

Differentiation between Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus based on carbohydrates in lipopolysaccharide

In the present study, the closely related facultative, Gram-negative rods, Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus, were distinguished taxonomically by means of their carbohydrate composition in phenol-extracted lipopolysaccharide. Both A. actinomycetemcomitans and H. aphrophilus lipopolysaccharide contained rhamnose, fucose, galactose, glucose, L-glycero-D-mannoheptose, galactosamine, and glucosamine. The content of galactose was approximately twice as high in lipopolysaccharide from H. aphrophilus as in lipopolysaccharide from A. actinomycetemcomitans. D-Glycero-D-mannoheptose was detected exclusively in lipopolysaccharide from A. actinomycetemcomitans where it constituted 11.8-16.7% of the sugar content. This aldoheptose may therefore serve as a marker for chemotaxonomic differentiation between A. actinomycetemcomitans and H. aphrophilus. The present study also describes fragmentation of methylheptoside derivatives of trifluoroacetic acid (D-glycero- and L-glycero-D-mannoheptose) from A. actinomycetemcomitans as suggested by mass spectrometry.

Haemophilus influenzae biotype VIII

Six Haemophilus influenzae strains could not be classified as biotypes I through VII. The strains were indole, urease, and ornithine decarboxylase negative. We propose that they be classified as biotype VIII, a previously unreported biotype.

Do children with recurrent Haemophilus influenzae otitis media become infected with a new organism or reacquire the original strain?

Using the techniques of outer membrane protein gel analysis and biotyping, we characterized nontypable Haemophilus influenzae isolates from middle ear aspirates of 30 children with recurrent nontypable H, influenzae (NTHI) otitis media. Nine of the 13 children with early recurrence of NTHI otitis (less than 30-day intervals) had respective first and second isolates that were identical. In contrast, 14 of 18 children with late recurrences of NTHI otitis (greater than 30-day intervals) had respective first and second isolates that were different, whereas four children had late recurrences with organisms that appeared to be identical with their respective initial infecting strains. These results suggest that early recurrent NTHI otitis usually is a result of relapse with the initial infecting NTHI strain. In contrast, late recurrent disease is usually the result of infection with a new organism. However, the observation that four children had late recurrences with the original strains suggests that strain-specific protective immunity may not uniformly develop after recovery from NTHI otitis.

Laboratory identification of Haemophilus influenzae: effects of basal media on the results of the satellitism test and evaluation of the RapID NH system

The effects of four different basal media, tryptic soy agar, brain heart infusion agar, nutrient agar, and Mueller-Hinton agar, were investigated with respect to the identification of Haemophilus influenzae with a satellitism test in which X and V growth factors were supplied by factor-impregnated filter paper strips. A total of 187 recent clinical isolates of H. influenzae were examined. Of these, 179 strains (95.7%) were correctly identified with tryptic soy agar, 173 (92.5%) with brain heart infusion agar, 105 (56.1%) with nutrient agar, and 133 (71.1%) with Mueller-Hinton agar. Failure to obtain a correct identification was usually the result of satelliting growth around V factor-containing strips, possibly due to the presence of trace amounts of hemin in the basal media, or was because of an absence of growth due to nutritional deficiencies in the basal media. All 187 H. influenzae strains were also examined with a new biochemical and chromogenic substrate micromethod, the RapID NH system (Innovative Diagnostics Systems, Inc., Decatur, Ga.). A total of 168 (89.8%) strains were correctly identified with this system.

Phenotypic differentiation of Pasteurella sensu stricto and the Actinobacillus group

The current classification of recognized actinobacilli and pasteurellas does not allow differentiation of the two genera by their phenotypic features. Recent investigations of their genetic relationships have shown that several species hitherto assigned to the genus Pasteurella are more closely related to the actinobacilli. Moreover, some recently described taxa were located by DNA-DNA hybridization in one or the other of the two genera. On the basis of the genetic system, improved identification keys have been devised which separate the taxonomic groups on the genus and species levels according to an appropriate set of biochemical characteristics.

Bacteremia caused by a beta-lactamase producing Haemophilus parainfluenzae strain of a new biotype. A case report

A case of Haemophilus parainfluenzae bacteremia without known infectious focus is reported. Phenotypically, the isolated strain is a typical H. parainfluenzae except for its ability to produce indole and beta-lactamase. Beta-lactamase producing H. parainfluenzae organisms are encountered occasionally, but to the best of our knowledge this is the first reported blood culture isolate with this ability. We propose a new biotype (IV) of H. parainfluenzae to accommodate strains that are indole, urease and ornithine decarboxylase positive.

Relative proportions of Haemophilus species in the throat of healthy children and adults

To determine normal proportions of pharyngeal Haemophilus species, qualitative and quantitative mapping of the species in the pharynx of ten healthy children and ten healthy adults was carried out using a selective and a non-selective medium. Haemophilus organisms were present in all samples, comprising approximately 10% of the total cultivable flora (range 0.6-36.9%). Haemophilus parainfluenzae was a member of the normal flora throughout life, constituting 74% of pharyngeal Haemophilus organisms. Haemophilus segnis and Haemophilus paraphrophilus occurred more frequently in samples from adults, whereas Haemophilus haemolyticus was present in only one sample. Non-encapsulated Haemophilus influenzae strains, usually of multiple biotypes, were present in 80% of the children but accounted for a mean of only 1.8% of the total flora. Their number decreased with increasing age; 40% of the adults harbored Haemophilus influenzae but only of a single biotype which constituted a minor proportion of the total flora (mean 0.15%). These findings suggest that host mechanisms can influence changes in the proportions of Haemophilus influenzae strains colonizing the host.

Phenotypic differentiation of Cardiobacterium hominis, Kingella indologenes and CDC group EF-4

Eleven strains of Cardiobacterium hominis, two strains of Kingella indologenes and six strains of CDC group EF-4 were characterized. Since all three taxa are oxidase-positive, fastidious gram-negative rods with relatively few positive reactions, they may be easily confused in the microbiological laboratory. Common characteristics are acid production from glucose, aerobic growth in semi-solid agar and very slow anaerobic growth. Group EF-4 is distinguished from the other two species by its capacity to produce catalase and its lack of indole production. Cardiobacterium hominis can be distinguished from Kingella indologenes by its ability to ferment mannitol and sorbitol and by differences in enzyme production. The three taxa also differ considerably with regard to morphological and cultural characteristics.

Susceptibility studies of multiply resistant Haemophilus influenzae isolated from pediatric patients and contacts

From February 1981 to December 1983, 225 strains were isolated from pediatric patients infected with Haemophilus influenzae. Forty-one strains were found to be resistant to ampicillin, chloramphenicol, and other antibiotics. They were isolated from 20 patients with invasive diseases (meningitis, 16; bacteremia, 4) and 21 with noninvasive diseases (otitis media, 19; conjunctivitis, 2). During this period, 44 patients with invasive diseases were seen (meningitis, 28; bacteremia, 16). Strains resistant to both ampicillin and chloramphenicol occurred in 45.4% of cerebrospinal fluid and blood isolates and in 51% of cerebrospinal fluid isolates only. In this group, individual resistance to ampicillin was 50%; chloramphenicol, 52.2%; tetracycline, 54.5%; and sulfamethoxazole-trimethoprim, 63.6%. No epidemiological relationship could be found among the patients. The presence of asymptomatic carriers was investigated in two nurseries and in eight family groups. From a total of 125 individuals studied, 80 were found to be colonized by H. influenzae, and 36 carried multiply resistant strains. From patients and carriers, 77 strains were found to be resistant to ampicillin, chloramphenicol, and other drugs; 39 belonged to type b (cerebrospinal fluid, 16; blood, 4; ear, 7; and nasopharynx, 12), and 38 were non-type b. The most frequent pattern of resistance was ampicillin-chloramphenicol-tetracycline-sulfamethoxazole-trimethoprim (94.8%), followed by ampicillin-chloramphenicol-tetracycline (3.9%). The disk diffusion method correctly predicted multiple resistance. The mean inhibition zone diameters were: ampicillin, 12.8 mm; chloramphenicol, 15.2 mm; tetracycline, 9.9 mm; and sulfamethoxazole-trimethoprim, 10.8 mm. These resistant strains were susceptible to cefotaxime, moxalactam, cefoperazone, cefuroxime, rifampin, and gentamicin. Our data suggest that in Spain the resistance of H. influenzae to ampicillin and chloramphenicol is endemic and that other effective therapeutic modalities are needed.

Characteristics of Haemophilus ducreyi in culture

Growth on different media and the influence of culture conditions were studied on 19 recently isolated strains of Haemophilus ducreyi, none of which had more than four passages on artificial media. The results were compared with 10 laboratory strains, which had an unknown number of passages in vitro. For all strains, growth was best on 30% rabbit blood agar and on Bieling agar. The laboratory strains showed a tendency to grow better on chocolate agar than did the fresh isolates. Of 19 fresh clinical isolates, 12 were CO2 dependent, and 2 needed extra moisture for growth. From the 10 laboratory strains, only one needed CO2 and none needed extra moisture. All 29 strains grew under anaerobic conditions. Of the 19 fresh clinical isolates, 12 grew at 22 degrees C, but only 2 of the 10 laboratory strains grew at this temperature. The laboratory strains grew better than the fresh isolates at 37 degrees C, and the optimal pH for all strains was pH 6.5 to 7.0. All strains showed starch aggregation.

Pathogenesis and prevention of recurrent infection after Haemophilus influenzae bacteremia

Recurrence of disease after Haemophilus influenzae bacteremia is relatively uncommon and may often be preventable. Three previously unreported and 11 reported occurrences in ten patients were evaluated in regard to pathogenesis. Recrudescence can be prevented by adequate culturing prior to therapy, proper treatment based on complete sensitivity testing and pharmacologic principles, and careful evaluation of clinical and microbiologic response. Relapse may be prevented in some instances by administering prophylactic rifampin to patients and close contacts who may be carriers of an infecting strain. Reinfections may be prevented through public health measures and the development of effective vaccines.

Distribution and relationship to serotype of Haemophilus influenzae biotypes isolated from upper respiratory tracts of children and adults in Papua New Guinea

The relationship between serotypes and biotypes of 505 carriage strains of Haemophilus influenzae isolated from the upper respiratory tracts of well children, children with pneumonia, and healthy adults was studied. All except serotype c were significantly associated with one or two specific biotypes (P less than 0.001). No encapsulated organisms belonging to biotypes V, VI, or VII were encountered. No significant difference in the interaction of biotypes and serotypes isolated from well and sick children was present. Both encapsulated and nonserotypable biotype I H. influenzae strains were commonly carried in the upper respiratory tracts of healthy Melanesian children. The distribution of nonserotypable H. influenzae strains occurred throughout all biotypes, and the frequency of nonencapsulated biotype III and IV strains differed significantly from serotypable organisms with the same biotype (P less than 0.001).

Biological characterization of Actinobacillus species and Pasteurella ureae

Forty-seven strains of Actinobacillus and eleven strains of Pasteurella urea were studied using 119 morphological, physiological and biochemical characters. The resulting data were subjected to numerical analysis using the complement of Gower's coefficient excluding negative matches. Clustering was by unweighted pair group average linkage. At distance level 0.30, seven phenons and five isolated strains (including one strain of "A. seminis ") were obtained. The seven phenons correspond to Actinobacillus lignieresii , A. suis, A. equuli , A. capsulatus, "A. salpingitidis ", Actinobacillus sp. (Ross) and P. ureae. The characteristics allowing identification of the seven phenons are tabulated.

Lack of evidence for the occurrence of Pasteurella ureae in rodents

The taxonomy of five typical human isolates of Pasteurella ureae, one strain of Actinobacillus hominis, and three murine isolates which had been designated as Pasteurella ureae in published reports were re-examined. Their taxonomic relationships were investigated by both conventional phenotypic characterization and by DNA/DNA hybridization using the renaturation method. The human Pasteurella urea strains were highly homogeneous in their phenotypes and in their DNA reassociation. The strain of Actinobacillus hominis studied was genetically distinct from Pasteurella ureae, but was located, like Pasteurella ureae, in the Actinobacillus group. The remaining strains exhibited only low DNA relatedness with Pasteurella ureae and each other; this agreed with their phenotypic divergence. Two of the murine isolates were identified as indole-negative variant strains of Pasteurella pneumotropica sensu stricto (i.e., type Jawetz), or of the type Heyl of Pasteurella pneumotropica, respectively. The remaining murine isolate appears to represent a hitherto unrecognized species of Pasteurellaceae. So far, there is no evidence for the occurrence of Pasteurella ureae outside the human host.