Immune responses to HBsAg conjugated to protein D of non-typeable Haemophilus influenzae in mice

Background

Hepatitis B vaccine that contains an aluminum hydroxide adjuvant induces apoptotic death of Hepa 1–6 cells. Difficult-to-degrade chemical additives in vaccines effectively enhance vaccine immunogenicity, but also affect the host tissue. Identification of bio-molecules that are readily degraded and compatible in vivo as an adjuvant is important for vaccine research. The hapten–carrier effect suggests that stimulation of helper T (Th) cells by carrier adjuvants is feasible. Protein D (PD) of non-typeable Haemophilus influenzae covalently conjugated to some polysaccharide vaccines has been confirmed to convert T-cell independent (TI) antigens into T-cell dependent (TD) antigens, and elicit strong T-cell responses ultimately. Herein, we would substitube PD for aluminum hydroxide adjuvant in Hepatitis B vaccine.

Methods and results

Truncated PD (amino acids 20–364) was expressed in Escherichia coli and purified by (NH₄)₂SO₄ precipitation and DEAE chromatography. After evaluation of antigenicity by western blotting, PD was covalently conjugated to yeast-derived recombinant HBsAg by cross-linking with glutaraldehyde. Intramuscular immunization with the conjugate induced higher level of HBsAg-specific antibody than did HBsAg alone (p < 0.05), and was comparable to commercial Hepatitis B vaccine. During the surveillance period (days 35–105), anti-HBs titers were hold high. Moreover, the conjugated vaccine enhanced Th1 immune responses, while Th2 responses were also activated and induced an antibody response, as determined by IFN-γ ELISPOT and IgG1/IgG2a ratio assays.

Conclusions

Recombinant truncated PD covalently conjugated to HBsAg antigen enhanced the immunogenicity of the antigen in mice simultaneously by humoral and cellular immune response, which would facilitate therapeutic hepatitis B vaccines.

Etiology and antimicrobial susceptibility of middle ear fluid pathogens in Costa Rican children with otitis media before and after the introduction of the 7-valent pneumococcal conjugate vaccine in the National Immunization Program: acute otitis media microbiology in Costa Rican children

Acute otitis media (AOM) microbiology was evaluated in children after 7-valent pneumococcal conjugate vaccine (PCV7) introduction in Costa Rica (private sector, 2004; National Immunization Program, 2009). This was a combined prospective and retrospective study conducted in a routine clinical setting in San José, Costa Rica. In the prospective part of the study, which was conducted post-PCV7 introduction (2010-2012), standard bacteriological procedures were used to evaluate the etiology and serotype distribution of middle ear fluid samples collected by tympanocentesis or otorrhea from children aged 3-59 months diagnosed with AOM. E-tests were used to evaluate antimicrobial susceptibility in culture-positive samples. Retrospective data recorded between 1999 and 2004 were used for comparison of bacterial etiology and serotype distribution before and after PCV7 introduction. Statistical significance was evaluated in bivariate analyses at the P-value < 0.05 level (without multiplicity correction). Post-PCV7 introduction, Haemophilus influenzae was detected in 118/456 and Streptococcus pneumoniae in 87/456 AOM episodes. Most H. influenzae isolates (113/118) were non-typeable. H. influenzae was more (27.4% vs 20.8%) and S. pneumoniae less (17.1% vs 25.5%) frequently observed in vaccinated (≥ 2 PCV7 doses or ≥ 1 PCV7 dose at >1 year of age) versus unvaccinated children. S. pneumoniae non-susceptibility rates were 1.1%, 34.5%, 31.7%, and 50.6% for penicillin, erythromycin, azithromycin, and trimethoprim/sulfamethoxazole (TMP-SMX), respectively. H. influenzae non-susceptibility rate was 66.9% for TMP-SMX. Between pre- and post-PCV7 introduction, H. influenzae became more (20.5% vs 25.9%; P-value < 0.001) and S. pneumoniae less (27.7% vs 19.1%; P-value = 0.002) prevalent, and PCV7 serotype proportions decreased among pneumococcal isolates (65.8% vs 43.7%; P-value = 0.0005). Frequently identified pneumococcal serotypes were 19F (34.2%), 3 (9.7%), 6B (9.7%), and 14 (9.7%) pre-PCV7 introduction, and 19F (27.6%), 14 (8.0%), and 35B (8.0%) post-PCV7 introduction. Following PCV7 introduction, a change in the distribution of AOM episodes caused by H. influenzae and pneumococcal serotypes included in PCV7 was observed in Costa Rican children. Pneumococcal vaccines impact should be further evaluated following broader vaccination coverage.

Clinical and molecular epidemiology of haemophilus influenzae causing invasive disease in adult patients

Objectives

The epidemiology of invasive Haemophilus influenzae (Hi) has changed since the introduction of the Hi type b (Hib) vaccine. The aim of this study was to analyze the clinical and molecular epidemiology of Hi invasive disease in adults.

Methods

Clinical data of the 82 patients with Hi invasive infections were analyzed. Antimicrobial susceptibility, serotyping, and genotyping were studied (2008–2013).

Results

Men accounted for 63.4% of patients (whose mean age was 64.3 years). The most frequent comorbidities were immunosuppressive therapy (34.1%), malignancy (31.7%), diabetes, and COPD (both 22%). The 30-day mortality rate was 20.7%. The majority of the strains (84.3%) were nontypeable (NTHi) and serotype f was the most prevalent serotype in the capsulated strains. The highest antimicrobial resistance was for cotrimoxazole (27.1%) and ampicillin (14.3%). Twenty-three isolates (32.9%) had amino acid changes in the PBP3 involved in resistance. Capsulated strains were clonal and belonged to clonal complexes 6 (serotype b), 124 (serotype f), and 18 (serotype e), whereas NTHi were genetically diverse.

Conclusions

Invasive Hi disease occurred mainly in elderly and those with underlying conditions, and it was associated with a high mortality rate. NTHi were the most common cause of invasive disease and showed high genetic diversity.

Cross reactivity of Neisseria meningitidis crgA diagnostic PCR primers with nontypeable haemophilus influenzae

BACKGROUND

CrgA based PCR are usually used for diagnosis of Neisseria meningitidis while the crgA gene was observed in the genomes of Haemophilus influenzae. In this study, we aimed to evaluate whether the crgA primers routinely used in the diagnosis of N. meningitidis could cross react with H. influenzae isolates.

METHODS

A diagnostic test study analysis of sixty-two H. influenzae isolates from oropharyngeal swabs of healthy individuals aged 9 to 11 years between 2011 and 2012, using commonly used crgA primers for diagnostic analysis of N. meningitidis.

RESULTS

It revealed that 19.3% nontypable H. influenzae isolates were positive for the crgA gene. All the biotype IV H. influenzae isolates were crgA PCR positive.

CONCLUSIONS

Our study has shown a significant finding of crgA gene especially in bitotype IV nontypable H. influenzae by N. meningitidis crgA diagnostic PCR primers. It is necessary to further evaluate the prevalence of the crgA gene in more non-typable H. influenzae strains, particularly invasive strains.

Risk of invasive Haemophilus influenzae infection during pregnancy and association with adverse fetal outcomes

IMPORTANCE

Unencapsulated Haemophilus influenzae frequently causes noninvasive upper respiratory tract infections in children but can also cause invasive disease, especially in older adults. A number of studies have reported an increased incidence in neonates and suggested that pregnant women may have an increased susceptibility to invasive unencapsulated H. influenzae disease.

OBJECTIVE

To describe the epidemiology, clinical characteristics, and outcomes of invasive H. influenzae disease in women of reproductive age during a 4-year period.

DESIGN, SETTING, AND PARTICIPANTS

Public Health England conducts enhanced national surveillance of invasive H. influenzae disease in England and Wales. Clinical questionnaires were sent prospectively to general practitioners caring for all women aged 15 to 44 years with laboratory-confirmed invasive H. influenzae disease during 2009-2012, encompassing 45,215,800 woman-years of follow-up. The final outcome was assessed in June 2013.

EXPOSURES

Invasive H. influenzae disease confirmed by positive culture from a normally sterile site.

MAIN OUTCOMES AND MEASURES

The primary outcome was H. influenzae infection and the secondary outcomes were pregnancy-related outcomes.

RESULTS

In total, 171 women had laboratory-confirmed invasive H. influenzae infection, which included 144 (84.2%; 95% CI, 77.9%-89.3%) with unencapsulated, 11 (6.4%; 95% CI, 3.3%-11.2%) with serotype b, and 16 (9.4%; 95% CI, 5.4%-14.7%) with other encapsulated serotypes. Questionnaire response rate was 100%. Overall, 75 of 171 women (43.9%; 95% CI, 36.3%-51.6%) were pregnant at the time of infection, most of whom were previously healthy and presented with unencapsulated H. influenzae bacteremia. The incidence rate of invasive unencapsulated H. influenzae disease was 17.2 (95% CI, 12.2-24.1; P < .001) times greater among pregnant women (2.98/100,000 woman-years) compared with nonpregnant women (0.17/100,000 woman-years). Unencapsulated H. influenzae infection during the first 24 weeks of pregnancy was associated with fetal loss (44/47; 93.6% [95% CI, 82.5%-98.7%]) and extremely premature birth (3/47; 6.4% [95% CI, 1.3%-17.5%]). Unencapsulated H. influenzae infection during the second half of pregnancy was associated with premature birth in 8 of 28 cases (28.6%; 95% CI, 13.2%-48.7%) and stillbirth in 2 of 28 cases (7.1%; 95% CI, 0.9%-23.5%). The incidence rate ratio for pregnancy loss was 2.91 (95% CI, 2.13-3.88) for all serotypes of H. influenzae and 2.90 (95% CI, 2.11-3.89) for unencapsulated H. influenzae compared with the background rate for pregnant women.

CONCLUSIONS AND RELEVANCE

Among women in England and Wales, pregnancy was associated with a greater risk of invasive H. influenzae infection. These infections were associated with poor pregnancy outcomes.

Haemophilus influenzae serotype a as a cause of serious invasive infections

Haemophilus influenzae, particularly H influenzae serotype b (Hib), is an important pathogen that causes serious diseases like meningitis and septicaemia. Since the introduction of Hib conjugate vaccines in the 1990s, the epidemiology of invasive H influenzae disease has changed substantially, with most infections now caused by non-Hib strains. We discuss the importance of H influenzae serotype a (Hia) as a cause of serious morbidity and mortality and its global epidemiology, clinical presentation, microbiology, immunology, prevention, and control. Much like Hib, the capsule of Hia is an important virulence factor contributing to the development of invasive disease. Molecular typing of Hia has identified distinct clonal groups, with some linked to severe disease and high case-fatality rates. Similarities between Hia and Hib capsules, their clinical presentation, and immunology of infection suggest that a bivalent Hia-Hib capsular polysaccharide-protein conjugate vaccine could offer protection against these two important serotypes of H influenzae.

Incidence survey of acute otitis media in children in Sado Island, Japan--Sado Otitis Media Study (SADOMS)

Background

Acute otitis media (AOM) is one of the most common forms of bacterial infection and cause for clinic visits in children. The incidence of AOM was 0.9–1.2 episodes per person-year during the first 2 years of life in previous reports conducted before 2000. The aim of this study was to 1) evaluate the latest AOM incidence in pediatric outpatients and 2) identify the bacterial pathogens from these patients and ascertain their serotypes and resistance.

Methods

The study was conducted in a closed population, involving all pediatricians and otolaryngologists in Sado Island allowing accurate determination of AOM incidence. In each month, one week was assigned as “surveillance week”, and all outpatients with acute illness aged 0–18 years examined during the surveillance weeks were enrolled. AOM was diagnosed on the basis of otoscopic findings and clinical symptoms were recorded. Specimens were collected from the nasopharynx or middle ear cavity of AOM patients and examined for bacteria. Antimicrobial susceptibilities, serotypes, and molecular typing for resistance were determined among Streptococcus pneumoniae and Haemophilus influenzae.

Results

In total, 8,283 clinic visits were conducted, and 354 episodes (4.3%, 95% CI: 3.9–4.7%) among 312 children were diagnosed as AOM. The incidence of AOM was highest in children of 1 year of age (0.54 episodes/child/year, 95% CI: 0.44–0.64). Serotype coverage of 7- and 13-valent pneumococcal conjugate vaccines in this study were 38.0% (95% CI: 29.3–47.3) and 62.8% (95% CI: 53.6–71.4), respectively. Of 122 H.influenzae isolates available for typing, 120 were nontypeable and 2 were type b. A high proportion of S. pneumoniae isolates (46%) showed resistance to penicillin. Approximately half of H. influenzae isolates had genetic markers for beta-lactamase-negative ampicillin-resistance.

Conclusions

Approximately 4–5% of pediatric outpatients, even without AOM-related symptoms, had AOM in our study. Pediatricians as well as otolaryngologists should check the tympanic membrane findings of all pediatric outpatients.

Resistance to complement-mediated killing and IgM binding to non-typeable Haemophilus influenzae is not altered when ascending from the nasopharynx to the middle ears in children with otitis media

We have previously found that non-typeable Haemophilus influenzae (NTHi) collected from the middle ear of children with otitis media (OM) exhibit increased levels of complement resistance compared to NTHi collected from the nasopharynx. However, it is unknown whether bacteria develop complement resistance in the middle ear, or whether resistance is present when residing in the nasopharynx. The objective of this study was to investigate whether the levels of complement resistance of isolates collected from the middle ear were similar to those of isolates from the nasopharynx with an identical MLST type. We included 62 children with recurrent acute OM, chronic OM with effusion or acute tympanostomy tube otorrhea. NTHi was simultaneously isolated from the nasopharynx and middle ear fluid. MLST, resistance to complement-mediated killing, IgG binding, IgM binding and phosphorylcholine expression was determined. In 41 children, NTHi isolated from the middle ear and nasopharynx showed to have an identical MLST type. Isolates collected from the middle ear showed a highly similar level of complement resistance and IgM binding with isolates collected from the nasopharynx, whereas this was not the case for IgG binding and phosphorylcholine incorporation into lipooligosaccharide. Resistance to complement-mediated killing and IgM binding of NTHi isolates with an identical MLST type collected from the middle ear and nasopharynx of children with OM was highly similar.

[The studies of elimination of nontypeable Haemophilus influenzae strains using the animal model of infection]

INTRODUCTION

The intranasal immunization is considered the effective method to induce immunological response in the mucosa and the model useful to develop the vaccine against otitis media due to nontypaeble Haemophilus influenzae infections. In the study, elimination of NTHi strains isolated from healthy and carrier individuals, varying with several genetic determinants, from mice nasopharynx, lungs and ears tissues and the interactions among strains during mixed infections were evaluated.

METHODS

Mice were infected with single and mixture of NTHi strains previously identified as non or potentially invasive. The curves of infections were drown from the averages of log cfu/mg values obtained for nasopharynx or ears leavages or lungs homogenates coupled with standard deviation at each time point using 5 mice. The significance of the differences was confirmed using ANOVA method.

RESULTS

The course of infections induced with a single noninvasive or potentially invasive strains in the mice nasopharynx, ear or lung tissues were not found to differ in respect to the level and duration. Regardless the strain used, higher elimination rates in the ear and lung tissues in comparison with nasopharynx were fund. Different rate of elimination was found in the case of mixture infections where the strain, determined in the previous study as potentially invasive, was dominating.

CONCLUSION

The concurrence model among not-invasive and potentially invasive NTHi strains in the host niche was thus confirmed using in vivo model of infection.

[Antibacterial susceptibility surveillance of Haemophilus influenzae isolated from pediatric patients in Gifu and Aichi prefectures (2009-2010)]

We investigated the susceptibility to antibacterial agents of 197 strains of Haemophilus influenzae isolated from pediatric patients at medical facilities in Gifu and Aichi prefectures between 2009 and 2010. Those strains were also examined for the mutations of ftsI coding for penicillin-binding protein 3, presence of bla TEM-1, serotype and beta-lactamase producing ability. Among the 197 strains, the most prevalent serotype was non-typeable (89.8%), followed by serotype b (8.1%), e (1.5%) and f (0.5%). Based on the susceptibility among the 197 strains to antibacterial agents, beta-lactamase nonproducing ampicillin-susceptible H. influenzae (BLNAS) accounted for 27.4%, beta-lactamase nonproducing ampicillin-resistant H. influenzae (BLNAR) for 62.4%, beta-lactamase producing ampicillin-resistant H. influenzae (BLPAR) for 6.1% and beta-lactamase producing amoxicillin/ clavulanic acid-resistant H. influenzae (BLPACR) for 4.1%. According to PCR-based genotyping, the strains were classified into 6 categories: gBLNAS, gLow-BLNAR, gBLNAR, gBLPAR, gBLPACR-I and gBLPACR-II. The incidences of each resistant class were 17.3% for gBLNAS, 6.6% for gLow-BLNAR, 66.0% for gBLNAR, 5.6% for gBLPAR and 4.6% for gBLPACR-II. The combined incidence of gLow-BLNAR and gBLNAR was 72.6%, which was higher than that of BLNAR (62.4%). The MIC90s of antibacterial agents against the 197 strains were as follows; 0.0156 microg/mL for tosufloxacin and garenoxacin, 0.0313 microg/mL for levofloxacin and pazufloxacin, 0.0625 microg/mL for norfloxacin, 0.25 microg/mL for tazobactam/piperacillin (TAZ/PIPC) and ceftriaxone, 0.5 microg/mL for TAZ/PIPC (1:8) and cefditoren, 1 microg/mL for piperacillin, cefteram, cefotaxime, meropenem, tebipenem and minocycline, 2 microg/mL for doripenem, 4 microg/mL for cefcapene, imipenem and azithromycin, 8 microg/mL for sulbactam/ampicillin, clavulanic acid/amoxicillin (1:2, CVA/AMPC) and cefdinir, 16 microg/mL for CVA/AMPC (1:14), flomoxef and clarithromycin, 32 microg/mL for ampicillin. Although there was no rapid increase in the antibacterial resistance, the prevalence of BLNAR was still over 50%. In order to ensure the appropriate chemotherapy, it is important to continue the surveillance of susceptibility among H. influenzae.

Nontypeable Haemophilus influenzae genetic islands associated with chronic pulmonary infection

Background

Haemophilus influenzae (Hi) colonizes the human respiratory tract and is an important pathogen associated with chronic obstructive pulmonary disease (COPD). Bacterial factors that interact with the human host may be important in the pathogenesis of COPD. These factors, however, have not been well defined. The overall goal of this study was to identify bacterial genetic elements with increased prevalence among H. influenzae strains isolated from patients with COPD compared to those isolated from the pharynges of healthy individuals.

Methodology/Principal Findings

Four nontypeable H. influenzae (NTHi) strains, two isolated from the airways of patients with COPD and two from a healthy individual, were subjected to whole genome sequencing using 454 FLX Titanium technology. COPD strain-specific genetic islands greater than 500 bp in size were identified by in silico subtraction. Open reading frames residing within these islands include known Hi virulence genes such as lic2b, hgbA, iga, hmw1 and hmw2, as well as genes encoding urease and other enzymes involving metabolic pathways. The distributions of seven selected genetic islands were assessed among a panel of 421 NTHi strains of both disease and commensal origins using a Library-on-a-Slide high throughput dot blot DNA hybridization procedure. Four of the seven islands screened, containing genes that encode a methyltransferase, a dehydrogenase, a urease synthesis enzyme, and a set of unknown short ORFs, respectively, were more prevalent in COPD strains than in colonizing strains with prevalence ratios ranging from 1.21 to 2.85 (p≤0.0002). Surprisingly, none of these sequences show increased prevalence among NTHi isolated from the airways of patients with cystic fibrosis.

Conclusions/Significance

Our data suggest that specific bacterial genes, many involved in metabolic functions, are associated with the ability of NTHi strains to survive in the lower airways of patients with COPD.

Rapid detection of Haemophilus influenzae and Haemophilus parainfluenzae in nasopharyngeal swabs by multiplex PCR

OBJECTIVE

To establish multiplex PCR-based assays for detecting H.influenzae and H.parainfluenzae. And the PCR-based assays were applied to detect the carriage rates of H.influenzae and H.parainfluenzae in nasopharyngeal swab specimens which were collected from healthy children.

METHODS

Multiplex primers for species-specific PCR were designed by using DNAstar soft based on the sequences of 16S rRNA genes from genus Haemophilus to detect H.influenzae and H.parainfluenzae.

RESULTS

The sensitivity of the 16S rRNA PCR assay for detecting H.influenzae and H.parainfluenzae was 97.53% and 100% respectively, and the specificity was 95.89% and 96.63% respectively. Youden's Index on the ability to detect H.influenzae and H.parainfluenzae was 0.9342 and 0.9663 respectively. 666 nasopharyngeal swab specimens were collected from healthy children. The detection rates of H.influenzae and H.parainfluenzae were 14.11% and 16.07% respectively by using isolation and culture methods. The detection rates of H.influenzae and H.parainfluenzae were 43.54% and 57.96% respectively by 16S rRNA PCR assays. The carriage rates of serotypes a, b, c, d, e, f and non-typeable isolates were 0% (0/666), 0.15% (1/666), 1.20% (8/666), 0.15% (1/666), 1.20% (8/666), 1.80% (12/666), 95.50% (636/666) respectively.

CONCLUSION

The multiplex PCR assays were very rapid, reliable and feasible methods for detection of H.influenzae and H.parainfluenzae in pharyngeal swab specimens which were compared to conventional isolation and culture methods. 95.5% of H.influenzae strains in healthy children were nontypeable. The encapsulated or typable strains were mainly three serotypes which was c, e, and f serotype.

International circumpolar surveillance interlaboratory quality control program for serotyping Haemophilus influenzae and serogrouping Neisseria meningitidis, 2005 to 2009

The International Circumpolar Surveillance (ICS) program was initiated in 1999 to conduct population-based surveillance for invasive pneumococcal disease in select regions of the Arctic. The program was expanded to include the surveillance of invasive diseases caused by Neisseria meningitidis and Haemophilus influenzae. An interlaboratory quality control (QC) program to monitor laboratory proficiencies in the serogrouping of N. meningitidis and serotyping of H. influenzae strains was codeveloped by the Arctic Investigations Program (Anchorage, AK) and the Public Health Agency of Canada National Microbiology Laboratory (Winnipeg, Manitoba, Canada) and introduced into the ICS program in 2005. Other participating laboratories included the Provincial Laboratory for Public Health (Edmonton, Alberta, Canada), Laboratoire Santé Publique du Québec (Sainte-Anne-de-Bellevue, Québec, Canada), and Statens Serum Institut (Copenhagen, Denmark). From 2005 through 2009, 50 isolates (24 N. meningitidis and 26 H. influenzae isolates) were distributed among the five participating laboratories. The overall serogroup concordance for N. meningitidis strains was 92.3% (96/104), without including three isolates that were found to express both serogroup Y and W135 specificities. Concordant results were obtained for serogroups A, B, C, and Y among all laboratories. Discrepancies were observed most frequently for serogroups W135, X, Z, and 29E. The overall serotype concordance for H. influenzae was 98% (125/127 attempts). The two discrepant results involved a serotype c strain and a serotype e strain, and in both cases, the serotypeable H. influenzae isolates were misidentified as being nontypeable. These data demonstrate a high degree of concordance for serogroup and serotype determinations of N. meningitidis and H. influenzae isolates, respectively, among the five laboratories participating in this quality control program.

Prevalence of β-lactamase-negative ampicillin-resistant haemophilus influenzae isolated from patients of a teaching hospital in Thailand

The aim of this study was to investigate the prevalence of β-lactamase-negative ampicillin-resistant (BLNAR) Haemophilus influenzae isolated from patients of a teaching hospital in Thailand. Eighty-eight isolates of H. influenzae were collected between September 2005 and March 2008. All isolates were identified and characterized for biotypes and capsular types. The β-lactamase production of these isolates was examined, and their susceptibility to the following 12 antimicrobial agents was determined: ampicillin (AMP), amoxicillin-clavulanate (AMC), cefotaxime (CTX), cefuroxime (CXM), meropenem (MEM), clarithromycin (CLR), telithromycin (TEL), tetracycline (TET), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (CHL). Of the 88 H. influenzae isolates, 69 (78.4%), 13 (14.8%), 4 (4.5%), and 2 (2.3%) were from the respiratory tract, pus, the genital tract, and blood, respectively. Half of the isolates were biotype II (44 isolates, 50%). The other half comprised biotypes I (23 isolates, 26.1%), III (15 isolates, 17.1%), and IV (6 isolates, 6.8%). All isolates were capsular non-typeable, except for 2 isolates that were type f. Antimicrobial susceptibility showed that all isolates were susceptible to AMC, CTX, MEM, TEL, CIP, and LEV (100%), whereas 96.6%, 94.3%, 80.7%, 68.2%, 50.0%, and 44.3% were susceptible to CXM, CLR, CHL, TET, AMP, and SXT, respectively. The β-lactamase-production rate of H. influenzae isolates was 40.9%, and the prevalence of BLNAR was 18.2%.

Severe soft tissue infection of the lower extremity caused by Haemophilus influenzae (serotype f, biotype II) in an adult patient

The infection caused by non-b-type Haemophilus influenzae has been increasing in this Hib (H.influenzae serotype b) vaccination era. H.influenzae serotype f (Hif) is considered as one of those emerging pathogens. In general, H.influenzae is a common pathogen of such as pneumonia, otitis media, and meningitis, but is rare in soft tissue infection, especially at the extremity. We report a rare case of severe soft tissue infection caused by Hif which occurred at the lower extremity of immunocompetent adult patient.

[Haemophilus influenzae nasopharyngeal colonization in children]

OBJECTIVE

to determine frequency, serotypes, biotypes and susceptibility to eight antibiotics in Haemophilus influenzae nasopharyngeal isolates in children under five years old from Mexico City.

METHODS

cross-sectional survey including children two months to five years old. A nasopharyngeal sample was taken. Haemophilus influenzae identification, serotyping, biotyping and antimicrobial susceptibility were performed.

RESULTS

a sample of 573 children were included. In 88/573 (15.3 %) H. influenzae was isolated, corresponding in 7/573 (1.2 %) to Hib, 3/573 (0.5 %) to Hi a, c, d, f and 78/573 (13.6 %) to Nontypable Hi. Among Hib carriers, 6 had received only one or two doses of specific vaccine. Biotype VIII (76.1 %) was the predominant. All isolates were susceptible to the antibiotics, but one Hib strain was resistant to erithromycin.

CONCLUSIONS

nontypable Haemophilus influenzae was predominant. Colonization by Hib in children under 5 years old was low (1.2 %), occurring in children with an incomplete vaccination schedule.

Molecular typing methods for outbreak detection and surveillance of invasive disease caused by Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae, a review

Invasive disease caused by the encapsulated bacteria Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae remains an important cause of morbidity and mortality worldwide, despite the introduction of successful conjugate polysaccharide vaccines that target disease-associated strains. In addition, resistance, or more accurately reduced susceptibility, to therapeutic antibiotics is spreading in populations of these organisms. There is therefore a continuing requirement for the surveillance of vaccine and non-vaccine antigens and antibiotic susceptibilities among isolates from invasive disease, which is only partially met by conventional methods. This need can be met with molecular and especially nucleotide sequence-based typing methods, which are fully developed in the case of N. meningitidis and which could be more widely deployed in clinical laboratories for S. pneumoniae and H. influenzae.

Increased level of intragenomic 16S rRNA gene heterogeneity in commensal strains closely related to Haemophilus influenzae

The 16S rRNA gene sequence of strains closely related to, but excluded from, Haemophilus influenzae was investigated and a conspicuously high number of polymorphic nucleotide positions due to intragenomic 16S rRNA gene heterogeneity was observed. The average frequency of 16S rRNA gene polymorphic nucleotide positions in 31 variant strains was 7.0×10(-3), which is approximately ten times the level observed in validated strains of H. influenzae. Sixty-seven polymorphic nucleotide positions in seven strains most likely originated from the simultaneous presence of two distinct types of helix 18 as a consequence of prior recombinatorial events. The increased level of 16S rRNA gene polymorphism in commensal taxa excluded from the pathogenic species H. influenzae is unexplained. The heterogeneity imposes difficulties on rRNA gene-based classification and systematics.

Biotyping, capsular typing, and antibiotic resistance pattern of Haemophilus influenzae strains in Iran

The aim of this study was to determine the capsular types of Haemophilus influenzae isolated from clinical specimens by slide agglutination serotyping (SAST) and PCR capsule typing methods. All the isolates were biotyped and their antibiotic resistance patterns also determined. Thirteen isolates of serotype b, 2 of serotype e, 4 of serotype f, and 19 nontypeable (NT) isolates were identified by SAST method in 38 H. influenzae culture-positive samples. Capsule typing by PCR increased the proportion of all invasive cases from 34.2% (by SAST) to 60.5%, and 6 culture-negative samples were identified as invasive H. influenzae (Hib) by this method. The discrepancy rate between SAST and PCR results were 41%. Biotypes I, II, and III were the prevalent biotypes whereas biotypes VI and VII were not found. The majority of capsule type b belonged to biotype II. The isolates were resistant to cotrimoxazole (47.1%) and ampicillin (43.6%). Multidrug resistance was observed in 7 of the isolates.

[Subtyping of lipooligosaccharides of non-typeable haemophilus influenzae isolated from children with bronchopulmonary diseases]

AIM

Subtyping of lipooligosaccharides (LOS) of non-typeable strains of Haemophilus influenzae (NTHi) isolated from children with bronchopulmonary diseases.

MATERIALS AND METHODS

Lipooligosaccharides obtained from 62 acapsular strains of H. influenzae were studied by vertical SDS-electrophoresis in PAAG.

RESULTS

Majority of LOS formed electrophoretically mobile components in low molecular mass zone. Obtained results allowed to differentiate 23 subtypes of LOS. Lipooligosaccharides of majority of strains (67.7%) belonged to one of 10 main subtypes, 30.6% of strains belonged to mixed subtypes because they had signs of 2-3 subtypes.

CONCLUSION

Strains possessing LOS of three subtypes--VI, VII, and X--were significantly more prevalent in pediatric patients (p < 0.05). More than one third (43.5%) of studied NTHi strains belonged to these subtypes.

Nontypeable Haemophilus influenzae and childhood pneumonia

Nontypeable Haemophilus influenzae (NTHi) is a common microbe frequently isolated from the nasopharynx of children. Bacterial pneumonia is a major cause of morbidity and mortality in children less than 5 years of age, with the burden of disease being greatest in developing countries. Determination of the bacterial aetiology of pneumonia is difficult due to sampling constraints. However, with a combination of sampling approaches, trans-thoracic fine-needle aspiration, blood culture and screened sputum, the evidence strongly suggests that NTHi is a significant causative pathogen of pneumonia in young children. However, further studies are required. The development of a new pneumococcal conjugate vaccine containing H. influenzae protein D has the potential to be beneficial against disease caused by NTHi, including pneumonia. With the implementation of this vaccine in many regions of the world where NTHi disease is endemic, it will be critical to introduce surveillance programs wherever it is used.

Genotypic characteristics of Haemophilus influenzae isolates from pediatric pneumonia patients in Chengdu city, Sichuan, China

Two hundred and seventy-three Haemophilus influenzae strains isolated from pediatric pneumonia patients in China were studied. We used Multilocus Sequence Typing (MLST) to analyze genotypic characteristics. All strains were biotyped and serotyped. Relatedness and patterns of genes among isolates were determined by the analysis of MLST and eBURST. H. influenzae primarily causes acute pneumonia in children under 1 year old. Nontypeable H. influenzae was responsible for most cases of pediatric pneumonia. All 273 strains were classified into eight biotypes. They mostly belonged to the I, II, and III biotypes (17.6%, 43.6%, and 22.7%, respectively). 62 strains (22.7%) produced beta-lactamase. We found 28 novel alleles. Fifty different STs were found by MLST, of which 39 were novel. These were ST477 through ST508 and ST521 through ST527. Group 17 and predicted founders 503 were new groups in this study. No STs correlated with strains from Korea, which is adjacent to China. The H. influenzae strains from China appeared to have heterogeneous ST types patterns which may be the reason no outbreaks or epidemics of H. influenzae infections have occurred in Chengdu city, Sichuan, China.

[Investigation on the carrier for Haemophilus influenzae in healthy population in Shenzhen]

OBJECTIVE

To Investigate the rate of carrying virus of Haemophilus influenzae in population of Shenzhen.

METHODS

Cross-sectional study was applied and 380 samples were recruited by cluster sampling in April to July 2008. The identification of H. influenzae strains were done according to the loboratory standard methodology described by Manual of Clinical Microbiology (American). All strains were biotyped according to Kilian's classification with the API NH system. And serotyped by a slide agglutination assay with type to a specific antiserum as described by Pittman. PCR method for identification of H. infiuenzae were performed as described by Falla.

RESULTS

The rate of carrying Haemophilus influenzae in population was 31.84% (121/380). The rate of 6-year groups was the highest (54.90%). The rate of 50-year groups was the lowest (8.51%). The rate of carrying Haemophilus influenzae had significant difference by age groups (chi2 = 30.172 P < 0.005). Eight biotypes were found among the 139 H. influenzae isolates. 7.91% (11/139) of all isolates belonged to biotype I, 37.41% (52/139) were biotype II, 34.53% (48/139) were biotype III, 4.32% (6/139) were biotype IV, 7.91% (11/139) were biotype V, 0.72% (1/139) were biotype VI, 6.47% (9/139) were biotype VII and 0.72% (1/139) were biotype VIII respectively. 97.14% (170/175) were nontypeable. There were five isolates were typeable. Two were serotype b. Three were serotype e. The rate of producing beta-lactamase was 14.38% (20/139).

CONCLUSION

The rate of carrying Haemophilus influenzae in healthy population of Shenzhen was high. The main isolates were type II and III. And the isolates were nontypeable H. influenzae primarily.