Incidence, predisposing factors and manifestations of invasive Haemophilus influenzae infections in adults

Epidemiology of Invasive Haemophilus influenzae Disease, Europe, 2007-2014

We describe the epidemiology of invasive Haemophilus influenzae disease during 2007-2014 in 12 European countries and assess overall H. influenzae disease trends by serotype and patient age. Mean annual notification rate was 0.6 cases/100,000 population, with an increasing annual trend of 3.3% (95% CI 2.3% to 4.3%). The notification rate was highest for patients <1 month of age (23.4 cases/100,000 population). Nontypeable H. influenzae (NTHi) caused 78% of all cases and showed increasing trends among persons <1 month and >20 years of age. Serotype f cases showed an increasing trend among persons >60 years of age. Serotype b cases showed decreasing trends among persons 1-5 months, 1-4 years, and >40 years of age. Sustained success of routine H. influenzae serotype b vaccination is evident. Surveillance systems must adopt a broad focus for invasive H. influenzae disease. Increasing reports of NTHi, particularly among neonates, highlight the potential benefit of a vaccine against NTHi.

Radiological findings in acute Haemophilus influenzae pulmonary infection

OBJECTIVE

The aim of this study was to assess pulmonary thin-section CT findings in patients with acute Haemophilus influenzae pulmonary infection.

METHODS

Thin-section CT scans obtained between January 2004 and March 2009 from 434 patients with acute H. influenzae pulmonary infection were retrospectively evaluated. Patients with concurrent infection diseases, including Streptococcus pneumoniae (n=76), Staphylococcus aureus (n=58) or multiple pathogens (n=89) were excluded from this study. Thus, our study group comprised 211 patients (106 men, 105 women; age range, 16-91 years, mean, 63.9 years). Underlying diseases included cardiac disease (n=35), pulmonary emphysema (n=23), post-operative status for malignancy (n=20) and bronchial asthma (n=15). Frequencies of CT patterns and disease distribution of parenchymal abnormalities, lymph node enlargement and pleural effusion were assessed by thin-section CT.

RESULTS

The CT findings in patients with H. influenzae pulmonary infection consisted mainly of ground-glass opacity (n=185), bronchial wall thickening (n=181), centrilobular nodules (n=137) and consolidation (n=112). These abnormalities were predominantly seen in the peripheral lung parenchyma (n=108). Pleural effusion was found in 22 patients. Two patients had mediastinal lymph node enlargement.

CONCLUSION

These findings in elderly patients with smoking habits or cardiac disease may be characteristic CT findings of H. influenzae pulmonary infection.

[Uncommon cause of respiratory distress in the post-anaesthesia care unit]

We report a case of respiratory distress in the post anesthesia care unit following general anaesthesia for a dilatation and curettage related to miscarriage in a 32-year-old woman. The preoperative physical examination showed no abnormalities except for the presence of dry cough during the preceding two or three days. A few minutes after her arrival in the PACU, the patient developed hyperthermia till 40.6 degrees C, cough, polypnea and oxygen desaturation (SpO(2): 82% on FiO(2): 40%). A thoraco-abdominal angioscanner showed pulmonary basal condensations and a thrombosis of the right ovarian vein. The patient had to be transferred to the intensive care unit where she remained intubated and ventilated during 13 days because of a Haemophilus influenzae pneumonia.

Genetic analysis of the capsule locus of Haemophilus influenzae serotype f

A 19-kb DNA region containing genes involved in the biosynthesis of the capsule of Haemophilus influenzae serotype f (Hif) has been cloned and characterized. The Hif cap locus organization is typical of group II capsule biosynthetic loci found in other H. influenzae serotype b bacteria and other gram-negative bacteria. However, the Hif cap locus was not associated with an IS1016 element. Three new open reading frames, Fcs1, Fcs2, and Fcs3, were identified in the Hif capsule-specific region II. The chromosomal location of the Hif cap locus and the organization of the flanking sequences differed significantly from previously described division I H. influenzae serotypes.

The impact of Haemophilus influenzae type b vaccination in Sweden

The number of patients with meningitis and bacteremia due to Haemophilus influenzae was studied in Sweden over the period 1987-1994. Conjugated H. influenzae type b vaccines were introduced in Sweden in 1992, and all children born after December 31, 1992, were offered vaccination free of charge. A rapid decline of H. influenzae meningitis and bacteraemia was observed in the autumn of 1993, when the expected peak incidence failed to appear. In the prevaccination period 1987-1991, the average annual incidence (cases/100,000) was 34.4 in children aged 0-4 years. In 1994, the annual incidence fell to 3.5. No significant decline was observed in older children or adults. There was a 92% reduction in the number of meningitis cases and an 83% reduction in cases of bacteraemia. A similar decline was noted in 2 regions which followed different strategies for the introduction of the vaccination programme.

Invasive Haemophilus influenzae disease: epidemiology and clinical spectrum before large-scale H. influenzae type b vaccination

In a prospective study between January 1987 and December 1992, 103 patients with invasive Haemophilus influenzae (Hi) infection were identified in a well-defined population before large-scale Haemophilus influenzae type b (Hib) vaccination was introduced. The incidence (case/100,000/year) of invasive Hi infection was 5.9 for the whole population, 55 for children 0-4 years old and as high as 2.8 for adults. Hib was the predominant cause of the infection (83 cases) in children but, in adults, 13/39 (30%) cases were caused by non-typable Hi and 6/39 (19%) by Hi serotype f. Three patients (3%) died and 6 (5.8%) suffered a permanent sequel from the infection. All patients with such a sequel had invasive Hib infection. No significant difference between patients 0-6 years old and matched controls regarding the frequency of subnormal serum levels of immunoglobulins was found.

Prospective epidemiological study of invasive Haemophilus influenzae disease in adults

The incidence and characteristics of invasive Haemophilus influenzae disease were studied in 43 adult patients admitted to the acute care hospitals in El Vallés County (Barcelona, Spain) between January 1987 and June 1992. The annual incidence of Haemophilus influenzae disease was 1.2 per 100,000 inhabitants. Pneumonia occurred in 24 patients, meningitis in five, intraabdominal infections in three, obstetric infections in two, epiglottitis in two and cellulitis in one. In six patients the source of infection was unknown. Ten (23%) of the infections were hospital acquired. Underlying conditions were diagnosed in 30 (70%) patients. Nontypeable Haemophilus influenzae strains predominated in all adult age groups. Sixty-one percent of type b and 34% of nontypeable strains were ampicillin resistant (p = 0.08). Multiple antibiotic resistance was also high among type b (53%) and nontypeable (18%) strains. The mortality rate was significantly higher in patients with pneumonia, bacteremia from an unidentified focus or shock at presentation.

Deep obstetrical and gynecological infections caused by non-typeable Haemophilus influenzae

Six patients with deep obstetrical and gynecological infections due to non-typeable Haemophilus influenzae are presented. 3 patients had tubo-ovarian abscesses, 2 septic abortions and 1 postpartum sepsis. All our patients with tubo-ovarian abscesses had used intra-uterine contraceptive devices until admission and all had a protracted course of illness. Both patients with septic abortion had a severe course, one of them with disseminated intravascular coagulation demanding treatment in the intensive care unit. The patient with postpartum infection had a milder course. The possibility of infection with H. influenzae and the emergence of beta-lactamase producing strains warrant adequate culture procedures in women with obstetrical and gynecological infections in order to ensure proper treatment.

Epidemiology of Haemophilus influenzae type b invasive disease in Wales

OBJECTIVE

To investigate the epidemiology of invasive disease due to Haemophilus influenzae type b, the clones responsible, and the antibiotic resistance of the isolates.

DESIGN

Prospective population based analysis of clinical and epidemiological data collected for Gwynedd during 1980-90 and in the whole of Wales during 1988-90.

SETTING

19 hospitals in Wales; all medical microbiology laboratories in Wales participated.

PATIENTS

82 patients with confirmed invasive infections caused by H influenzae type b in Gwynedd during 1980-90 and 207 in Wales during 1988-90.

MAIN OUTCOME MEASURES

Clinical and epidemiological measures; analysis of the clonal types of the isolates based on the electrophoretic mobilities of 17 metabolic enzymes; and antibiotic resistance.

RESULTS

The annual incidence of H influenzae type b infections in Gwynedd was 3.2 cases/100,000 and in Wales was 2.5 cases/100,000. Most cases occurred in children aged under 5 years, the highest annual incidence being in those aged under 1 (84.6/100,000 and 56.9/100,000 in Wales). The cumulative risk of acquiring H influenzae type b disease by the fifth birthday was one in 456 in Gwynedd and one in 578 in Wales. Fifteen per cent of cases in Gwynedd and 7% of those in Wales occurred in adults. Predominant clinical conditions were meningitis in children and pneumonia in adults. In Gwynedd 2/70 (3%) children and 5/12 (42%) adults died. Long term neurological sequelae occurred in 8% (4/48) of children who survived haemophilus meningitis. Children presenting with infection were usually the youngest members of their family. No secondary household cases were identified. 100 of 128 (78%) strains were of a single clone, electrophoretic type 12.5, and 4/207 (1.9%) isolates from Wales were resistant to both ampicillin and chloramphenicol.

CONCLUSIONS

The annual rate of infection in children aged under 5 in four Welsh counties was 12-44% higher than that previously published for the United Kingdom. The study emphasises the potential value of a vaccine effective in early infancy and provides baseline data to assess its efficacy after its introduction. Alternatives to ampicillin and chloramphenicol should be used as first line, empirical treatment for severe infections that might be caused by H influenzae type b in Wales.

Serious systemic infection caused by non-encapsulated Haemophilus influenzae biotype III in an adult

Haemophilus influenzae is the aetiological agent in less than 1% of septic arthritis cases in adults and most often serotype b is involved. We report here a case of severe systemic infection due to non-encapsulated H. influenzae biotype III in a 40-year-old man, previously healthy although alcohol abuser. Cholangitis and acute alcoholic hepatitis were diagnosed simultaneously. The organism was grown from blood and from synovial fluid of the left knee, but several other joints were also affected. The close relationship between H. influenzae biotype III and H. aegyptius is mentioned in view of recent reports of fatal childhood illness caused by a special clone of H. aegyptius and the importance of reporting both serotype and biotype in severe H. influenzae induced disease is emphasized.

Acute epiglottitis in children and adults in Sweden 1981-3

In a retrospective study of the incidence of acute epiglottitis in Sweden, 485 children and 356 adults fulfilled the following criteria: (a) red and swollen epiglottis visualised at laryngoscopy; (b) stridor or difficulties in swallowing own saliva or water; and (c) temperature greater than or equal to 38 degrees C. The age specific incidence in children (0-14 years) was 10 and in adults (greater than or equal to 15 years) 1.8/100,000/year. These incidence rates were higher than the incidence of Haemophilus influenzae meningitis in the same population. Blood cultures were obtained from 290 children (60%) and 185 adults (52%). H influenzae was isolated from 267 blood cultures (92%) from children and 98 blood cultures from adults (53%). Other organisms were isolated from six adults (3%). An artificial airway was established in 352 children (73%) and in 68 adults (19%); the remainder were treated conservatively. Six children and two adults died. Sweden has a high incidence of acute epiglottitis in children and the disease also occurs in adults. The importance of H influenzae in the aetiology of epiglottitis in all age groups is confirmed, but in adults many cases occur without septicaemia. The mortality is currently very low.

Haemophilus isolated from unusual anatomical sites

During a 15-year period Haemophilus species were isolated from unusual anatomical sites in 80 patients, mostly adults. The origin of specimens was pus and swabs from suppurative lesions, fluids from serosal cavities and gall bladder, gut content, and blood in cases with a supposed tissue focus. In 17 patients Haemophilus species were isolated in pure culture, in 63 patients in conjunction with other bacteria. 17 patients had gynaecological complaints: bartholinitis, salpingitis, and vaginal discharge. 22 patients had gastrointestinal complaints, comprising 17 with appendicitis, peritonitis following perforation of gastric ulcer, gall-duct infections, and an abscess in the stomach wall, and 5 patients with colonization of the gut. 41 patients had soft tissue and bone infections.

Haemophilus influenzae type b infections in adults

31 cases of invasive Haemophilus influenzae type b infections occurred in adults in Denmark during a period of 2 years and 5 months corresponding to an incidence of 0.3/100,000/year. Only 6 patients had no underlying condition. The incidence of H. influenzae type b infections in adults will probably rise in the future, because the increasing use of therapeutic measures affecting the immune system will lead to an increase in the number of susceptible patients.

Development of serum antibodies of the immunoglobulin G class and subclasses against the capsular polysaccharide of Haemophilus influenzae type b in children and adults with invasive infections

The development of total immunoglobulin G (IgG) antibodies and antibodies of the four IgG subclasses in serum against Haemophilus influenzae type b capsular polysaccharide (CPS) was studied in 24 children and 11 adults with invasive Haemophilus influenzae type b infections, by using an enzyme-linked immunosorbent assay. None of the 8 children aged 10 months or younger had increases in the IgG class or in any of the IgG subclasses. In contrast, 14 of 16 children between 10 months and 6 years of age and 10 of 11 adults had significant increases in total IgG, IgG1, or IgG2 antibodies in various combinations, but none of them had increases in IgG3 or IgG4 antibodies. The increases in IgG1 and IgG2 antibodies in the children were of similar magnitudes. Of 11 adult patients, 9 had significant increases in IgG2 antibodies, while only 4 had increases in IgG1 antibodies. In conclusion, this study shows that children younger than approximately 1 year have no IgG response to H. influenzae type b CPS, while individuals above this age have a mixed IgG1 and IgG2 response.

A comparison between methods of identification and serotyping of encapsulated strains of Haemophilus influenzae

Seven methods of serotyping of Haemophilus influenzae were evaluated. Comparing slide agglutination, staphylococcal coagglutination, latex agglutination, counterimmunoelectrophoresis, immunofluorescence, capsular swelling, and cultivation on antiserum agar the commercial coagglutination test was most reliable, most rapid, and easiest to perform. To identify all six serotypes this coagglutination test had to be combined with slide agglutination. With most methods best results were achieved by using cultures incubated at 37 degrees C for 6 h. As nonencapsulated strains often agglutinated unspecifically, selection of probably typeable strains was useful. Differentiation with help of colonial morphology and opalescent growth was facilitated by cultivation on Brain Heart Infusion (BHI) Chocolate Agar and testing of growth factor requirements on translucent BHI Agar with strips containing the growth factors V, X, and VX, respectively. In broth turbid growth was a hint for encapsulation. Nigrosin staining, a negative capsule staining, proved to be useful if specific antisera are not available. From 252 clinical isolates of H. influenzae 216 were not typeable. 36 strains could be serotyped. 27 (75%) belonged to serotype b, 6 (16.6%) were serotype e, 3 (8.3%) were serotype f. Serotype e and f were most difficult to identify. Spectrum of patients and diseases were corresponding to the findings of other authors. Less well-known infections like cellulitis (erysipelas of the cheeks) and arthritis were observed, too. Rapid identification of at least H. influenzae type b could render treatment in some cases more effective by early application of a suitable antibiotic.

Haemophilus influenzae type b septicaemia associated with myonecrosis and thigh abscess

A case is reported of a male adult with Haemophilus influenzae type b septicaemia and subsequent abscess in the left thigh due to this microorganism following injection of phenylbutazone. The phenylbutazone probably caused muscle cell damage. It is assumed that Haemophilus influenzae type b colonized the site during an episode of septicaemia, with subsequent development of necrosis and abscess.

Identification of Haemophilus influenzae type b by a monoclonal antibody coagglutination assay

A coagglutination assay using monoclonal antibody is described for the identification of Haemophilus influenzae type b. An immunoglobulin G2a monoclonal antibody, Hb-2, directed against a serotype-specific outer membrane protein of H. influenzae type b was adsorbed to Staphylococcus aureus Cowan 1 cells. In a dot enzyme immunoassay, Hb-2 reacted with 453 of 455 H. influenzae type b isolates and did not react with H. influenzae of other serotypes, untypeable H. influenzae strains, or other bacterial species. The Hb-2 coagglutination assay was evaluated by testing 136 H. influenzae type b strains selected on the basis of multilocus enzyme genotypes, 5 strains of another serotype, and 94 untypeable H. influenzae strains. The specificity of the coagglutination assay was demonstrated by the inhibition of the reaction by free Hb-2 monoclonal antibodies. The coagglutination assay was as specific as the dot enzyme immunoassay and can be rapidly performed and easily interpreted.

Haemophilus influenzae meningitis in Sweden 1981-1983

Four hundred and seventy cases of meningitis caused by Haemophilus influenza in children and 30 cases in adults were identified in Sweden between 1981 and 1983. The age specific incidence in the most susceptible age group (0-4 years) was 31/100,000/year (440 cases), which is higher than previously reported from Europe. A further 30 cases were seen in children aged 5-14. The risk of developing H influenzae meningitis before the age of 15 was 1 in 669. There were 11 deaths (2%) and five cases of serious neurological sequelae among the children. Only 18 children (4%) had predisposing diseases. All but one of the 294 strains of H influenzae from children that had been serotyped were type b. Infections in adults differed from infections in children. Five of the adults died (17%), 12 had important predisposing diseases, and at least six of the infections were caused by non-typable strains. It is concluded that research into the prevention of invasive H influenzae infections in children should have high priority.

Types and subtypes of 73 strains of Haemophilus influenzae isolated from patients more than 6 years of age with meningitis in The Netherlands

Strains of Haemophilus influenzae isolated in The Netherlands between 1975 and 1984 from patients with meningitis were analysed in order to determine whether older patients are infected with particular types or subtypes of the organism. Of 1154 patients with H. influenzae meningitis 73 (6.3%) were more than 6 years of age. Thirty-one strains (42%) were of serotype b, one strain was of serotyped, one strain was of serotype f and 40 strains (55%) were non-typable. Twenty-eight type b strains were available for subtyping by analysis of the major outer-membrane proteins by sodium dodecylsulphate (SDS)-polyacrylamide gel electrophoresis (PAGE), by serotyping of their lipopolysaccharides and by biotyping. Twenty-one strains were outer-membrane protein subtype 1,24-lipopolysaccharide serotype 1 and 24 biotype I. Seventeen strains (61%) combined these characteristics. This percentage did not differ significantly from the percentage found for strains isolated from patients of all age groups (80%). The 32 non-typable H. influenzae strains analysed had different outer-membrane protein patterns as seen by SDS-PAGE. Five biotypes were found, among which biotype II was predominant (21/32). The results indicated that (i) patients more than 6 years of age were infected by subtypes of H. influenzae b strains which were not significantly different from the strains isolated from younger patients, (ii) non-typable strains of H. influenzae were much more common (55%) in the older age group than in the younger (1.2%) and (iii) that these non-typable strains were not of a particular subtype.

Aetiology of community-acquired pneumonia in hospital treated patients

From May 1982 a prospective 1-year study of adult patients with community-acquired, radiologically verified, hospital treated pneumonia was performed at the Department of Infectious Diseases, Orebro Medical Center Hospital, Orebro, Sweden. The study included 147 patients with a median age of 71 years. Special efforts to diagnose a pneumococcal aetiology were accomplished by antigen detection of the pneumococcal C-polysaccharide (PnC) in sputum and saliva samples and by serological methods for determination of antibody titres against PnC. A pneumococcal aetiology was established in 46.9% of the patients, including 8.1% with double infections. Altogether Haemophilus influenzae A virus were noted in 9.5%, respectively, Mycoplasma pneumoniae in 5.4%, legionnaires' disease in 2.7% and Branhamella catarrhalis in 2.0%, whereas enteric gram-negative bacilli as aetiological organisms were not found in any patient. These findings imply that penicillin should still be the first drug of choice in hospitalized adult patients with community-acquired pneumonia in Sweden.

Invasive infections caused by Haemophilus species other than Haemophilus influenzae

In a retrospective study covering a 13-year period and a population of 817,900 inhabitants, 13 cases of invasive infection caused by Haemophilus species other than Haemophilus influenzae were found. Ten of the infectious episodes were caused by Haemophilus parainfluenzae and three by Haemophilus aphrophilus. The clinical manifestations comprised endocarditis, meningitis, pleuropneumonia, epiglottitis and septicaemia from an unknown focus. These 13 infectious episodes caused by uncommon Haemophilus species constituted less than 3% of the total number (473) of invasive Haemophilus infections registered during the same period of time. Invasive H. influenzae infections were more common in all age groups than infections caused by other Haemophilus species. In contrast to H. influenzae infections, which predominate in childhood, invasive infections due to uncommon Haemophilus species had no predilection for any age group.