The taxonomy of haemophili isolated from conjunctivae

Analysis of genetic relatedness of Haemophilus influenzae isolates by multilocus sequence typing

The gram-negative bacterium Haemophilus influenzae is a human-restricted commensal of the nasopharynx that can also be associated with disease. The majority of H. influenzae respiratory isolates lack the genes for capsule production and are nontypeable (NTHI). Whereas encapsulated strains are known to belong to serotype-specific phylogenetic groups, the structure of the NTHI population has not been previously described. A total of 656 H. influenzae strains, including 322 NTHI strains, have been typed by multilocus sequence typing and found to have 359 sequence types (ST). We performed maximum-parsimony analysis of the 359 sequences and calculated the majority-rule consensus of 4,545 resulting equally most parsimonious trees. Eleven clades were identified, consisting of six or more ST on a branch that was present in 100% of trees. Two additional clades were defined by branches present in 91% and 82% of trees, respectively. Of these 13 clades, 8 consisted predominantly of NTHI strains, three were serotype specific, and 2 contained distinct NTHI-specific and serotype-specific clusters of strains. Sixty percent of NTHI strains have ST within one of the 13 clades, and eBURST analysis identified an additional phylogenetic group that contained 20% of NTHI strains. There was concordant clustering of certain metabolic reactions and putative virulence loci but not of disease source or geographic origin. We conclude that well-defined phylogenetic groups of NTHI strains exist and that these groups differ in genetic content. These observations will provide a framework for further study of the effect of genetic diversity on the interaction of NTHI with the host.

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.

Haemophilus influenzae corneal ulcer in a therapeutic contact lens wearer

Haemophilus influenzae is an unusual corneal pathogen and an unusual cause of corneal ulcers in Western society. In previous reports corneal complications from H. influenzae have been secondary to a conjunctivitis. The first case of a primary H. influenzae corneal ulcer as a complication of therapeutic contact lens wear is presented. Since other uncommon bacteria have been reported as causes of contact lens related corneal ulcers, the bacteriology of contact lens related corneal ulcers is reviewed. Ophthalmologists need to be aware that H. influenzae infections in adults are becoming more frequent.

Aetiology and treatment of acute bacterial infection of the external eye

The microbial flora of 738 patients with acute bacterial conjunctivitis, corneal ulceration, blepharitis, dacryocystitis, and discharging sockets has been investigated. Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae were the main pathogens isolated. Str. viridans was associated with conjunctivitis in patients aged under 1 year. moraxella sp. was isolated on only one occasion. Overall, 40% of specimens were associated with Staph. epidermidis or mixed skin flora, which also occurred with cultures of the normal eye. Clostridium welchii was isolated on 3 occasions but was not associated with bullae or gas gangrene. The least overall resistance, of 6%, was to chloramphenicol, but no one antibiotic was effective against all pathogens. Gentamicin remains the antibiotic of choice for Pseudomonas aeruginosa infection.

Rapid biochemical characterization of Haemophilus species by using the micro-ID

Biotyping of Haemophilus influenzae into five type and H. parainfluenzae into three types based on indole production, ornithine decarboxylase, and urease has been reported (M. Kilian, Acta Pathol. Microbiol. Scand. Sect. B 82:835--842, 1976). A commercially available test system designed for the 4-h identification of Enterobacteriaceae. Micro-ID, proved efficacious for the rapid biotyping of these two Haemophilus species. The nitrate reductase, indole production, ornithine decarboxylase, urease, and o-nitrophenyl-beta-D-galactopyranoside hydrolysis tests in Micro-ID correlated over 99% with conventional methodology. By utilizing the indole and o-nitrophenyl-beta-D-galactopyranoside tests it was possible, with 261 of 272 (96.1%) isolates, to distinguish H. influenzae from H. parainfluenzae. Cerebrospinal fluid isolates were over 90% H. influenzae biotype I, and conjunctival isolates were approximately 70% biotype II. Type b H. influenzae were predominantly biotypes I and II; these type b isolates were also overwhelmingly indole producers. Although over 90% of biotypes I and II have been reported to produce beta-lactamase, this was not confirmed by the small number of beta-lactamase producers encountered here. The 4-h Micro-ID should prove a useful mechanism, amenable to the routine clinical laboratory, for the further exploration of the association of Haemophilus with the site of isolation, antigenicity, and antibiotic resistance.