Invasive Haemophilus influenzae Disease at Texas Children's Hospital, 2011 to 2018

Clinical Practice Guideline by the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA): 2023 Guideline on Diagnosis and Management of Acute Bacterial Arthritis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute bacterial arthritis (ABA) in children was developed by a multidisciplinary panel representing the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with ABA, including specialists in pediatric infectious diseases and orthopedics. The panel's recommendations for the diagnosis and treatment of ABA are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of ABA in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) (see Figure 1). A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

Postmeningitic pediatric hearing loss from non-type b Haemophilus influenzae

BACKGROUND

Postmeningitic hearing loss from Haemophilus influenzae (H. influenzae) is increasingly due to encapsulated serotypes other than type b (Hib) and nontypeable strains (collectively, nHiB H. influenzae). Pediatric hearing loss after nHib H. influenzae meningitis remains poorly described.

METHODS

Retrospecive case series of nHiB H. influenzae meningitis cases identified from a microbiologic database at Children's Hospital Colorado from 2000 to 2020. Literature regarding nHiB H. influenzae and H. influenzae postmeningitic hearing loss was also reviewed.

RESULTS

Eleven cases of nHib H. influenzae meningitis (median age 15.9 months) were identified due to serotype f (36 %), serotype a (27 %), and nontypable strains (36 %). Seven (64 %) patients were male, 55 % were white and 18 % were Hispanic or Latino. Hearing loss was initially identified in 4 children (40 %), with two patients with moderate conductive hearing loss (CHL) and one child with unilateral moderate sensorineural (SNHL) hearing loss patients recovering normal hearing. One patient with bilateral profound sensorineural hearing loss and associated labyrinthitis ossificans required cochlear implantation. All children (4) with identified hearing loss were noted to have additional intracranial sequelae, which included empyema (2), sinus thrombosis (2), and seizures (2). Of patients receiving steroids, 25 % had hearing loss on initial testing, compared to 66 % of those who did not receive steroids.

CONCLUSIONS

nHib H. influenzae can cause both transient and permanent postmeningitic hearing loss. Steroids may offer otoprotection in nHib H. influenzae meningitis similar to Hib meningitis. Given the limited literature, further study is needed to better characterize hearing outcomes after nHib H. influenzae meningitis.

Pathogens in PICU before and during the SARS-CoV-2 pandemic in China: a multicenter retrospective study

BACKGROUND

Nonpharmacological interventions for COVID-19 could reduce the incidence of children hospitalized in pediatric intensive care units (PICU) and the incidence of children with bacterial infections. This study aimed to evaluate changes in the bacterial profile of children in PICU before and during the COVID-19 pandemics.

METHODS

This is a retrospective study, involving clinical data of children with positive bacterial cultures admitted to the PICU respectively in 2019 and 2021.

RESULTS

In total 652 children were included in this study. The total number of hospitalized patients and the incidence of bacteria-positive children in 2021 were lower than those in 2019. There were no significant differences in the ratio of Gram-positive bacterial infection, Gram-negative bacteria infection or fungi infection between the two years. The rate of Streptococcus pneumoniae in 2021 was higher than that in 2019(p = 0.127). The incidence of Haemophilus influenzae in hospitalized patients decreased with a downward trend(p = 0.002). The distribution of previous underlying diseases in children admitted to PICU with different outcomes of bacterial infection between the two years were homogeneous (p > 0.05).

CONCLUSION

After the implementation of COVID-19 isolation, prevention and control measures, the number of hospitalizations and bacterial infections in PICU decreased, which may be due to changes in population's behavior patterns. Meanwhile, the incidence of Haemophilus influenzae in hospitalized patients decreased with a downward trend.

Characterization of Serotypes and Molecular Drug Resistance Patterns of Haemophilus influenzae in Kunming Children

The present study aimed to determine the capsular serotype distribution and antimicrobial drug resistance patterns of Haemophilus influenzae from children in the Kunming region of China. This information could guide policymakers in clinical treatment. In the present study, H. influenzae isolates were tested for their serotypes, antimicrobial susceptibility pattern, and presence of β-lactamases. One-hundred forty-eight H. influenzae strains isolated from children 0-2 years old were investigated for capsular types by glass slide agglutination and molecular methods, and biotyped by the biochemical reactions. The drug resistance-encoding genes TEM-1, ROB-1, and the ftsI gene mutations PBP3-3, and PBP3-BLN were detected with real-time quantitative polymerase chain reaction (qPCR). The prevalence of β-lactamase-producing strains (60.3%) was significantly higher (p < 0.05) than non-enzyme-producing strains. β-Lactamase-producing strains were multidrug resistant to various antibiotics such as ampicillin, tetracycline, sulfamethoxazole/trimethoprim, chloramphenicol, cefuroxime, and cefaclor. Among β-lactamase-producing strains, the detection rates of the TEM-1, PBP3-BLN, PBP3-s, and ROB-1 were 54.1%, 18.9%, 11.8%, and 6.9%, respectively. The biotyping results show that most H. influenzae strains were of type II and III. Non-typeable H. influenzae (NTHi) accounted for 89.3% of the strains. NTHi strains were the most prevalent in this region; most belonged to biological types II and III. β-Lactamase-positive ampi-cillin-resistant (BLPAR) strains were prevalent among H. influenzae isolates in this region.

Secondary Cases of Invasive Disease Caused by Encapsulated and Nontypeable Haemophilus influenzae - 10 U.S. Jurisdictions, 2011-2018

Haemophilus influenzae (Hi) can cause meningitis and other serious invasive disease. Encapsulated Hi is classified into six serotypes (a-f) based on chemical composition of the polysaccharide capsule; unencapsulated strains are termed nontypeable Hi (NTHi). Hi serotype b (Hib) was the most common cause of bacterial meningitis in children in the pre-Hib vaccine era, and secondary transmission of Hi among children (e.g., to household contacts and in child care facilities) (1,2) led to the Advisory Committee on Immunization Practices (ACIP) recommendation for antibiotic chemoprophylaxis to prevent Hib disease in certain circumstances.* High Hib vaccination coverage since the 1990s has substantially reduced Hib disease, and other serotypes now account for most Hi-associated invasive disease in the United States (3). Nevertheless, CDC does not currently recommend chemoprophylaxis for contacts of persons with invasive disease caused by serotypes other than Hib and by NTHi (non-b Hi). Given this changing epidemiology, U.S. surveillance data were reviewed to investigate secondary cases of invasive disease caused by Hi. The estimated prevalence of secondary transmission was 0.32% among persons with encapsulated Hi disease (≤60 days of one another) and 0.12% among persons with NTHi disease (≤14 days of one another). Isolates from all Hi case pairs were genetically closely related, and all patients with potential secondary infection had underlying medical conditions. These results strongly suggest that secondary transmission of non-b Hi occurs. Expansion of Hi chemoprophylaxis recommendations might be warranted to control invasive Hi disease in certain populations in the United States, but further analysis is needed to evaluate the potential benefits against the risks, such as increased antibiotic use.

Epidemiology of invasive Haemophilus influenzae serotype a disease in the North American Arctic, 2006-2017

Invasive Haemophilus influenzae type a (iHia) disease was detected in Alaska and Northern Canada in 2002 and 2000, respectively. From 2006 to 2017, 164 iHia cases (Alaska=53, Northern Canada=111) were reported. Rates of iHia disease per 100,000 persons were higher in Northern Canada compared to Alaska and were significantly higher in Indigenous (Alaska 2.8, Northern Canada 9.5) compared to non-Indigenous populations (Alaska 0.1, Northern Canada=0.4). Disease rates were highest in Indigenous children <2 years of age (Alaska 56.2, Northern Canada=144.1) and significantly higher than in non-Indigenous children <2 (Alaska 0.1, Northern Canada 0.4). The most common clinical presentation in children <5 years was meningitis of age and pneumonia in persons ≥5 years old. Most patients were hospitalised (Alaska=87%, Northern Canada=89%) and fatality was similar (Alaska=11%, Northern Canada=10%). MLST testing showed sequence types ST23 and ST576 in Northern Canada and ST576, ST23 and ST56 in Alaska. Alaska and Northern Canada have high rates of iHia disease. A vaccine is needed in these regions to protect young children.

Haemophilus influenzae Protein D antibody suppression in a multi-component vaccine formulation

Nontypeable Haemophilus influenzae (NTHi) has emerged as a dominant mucosal pathogen causing acute otitis media (AOM) in children, acute sinusitis in children and adults, and acute exacerbations of chronic bronchitis in adults. Consequently, there is an urgent need to develop a vaccine to protect against NTHi infection. A multi-component vaccine will be desirable to avoid emergence of strains expressing modified proteins allowing vaccine escape. Protein D (PD), outer membrane protein (OMP) 26, and Protein 6 (P6) are leading protein vaccine candidates against NTHi. In pre-clinical research using mouse models, we found that recombinantly expressed PD, OMP26, and P6 induce robust antibody responses after vaccination as individual vaccines, but when PD and OMP26 were combined into a single vaccine formulation, PD antibody levels were significantly lower. We postulated that PD and OMP26 physiochemically interacted to mask PD antigenic epitopes resulting in the observed effect on antibody response. However, column chromatography and mass spectrometry analysis did not support our hypothesis. We postulated that the effect might be in vivo through the mechanism of protein vaccine immunologic antigenic competition. We found when PD and OMP26 were injected into the same leg or separate legs of mice, so that antigens were immunologically processed at the same or different regional lymph nodes, respectively, antibody levels to PD were significantly lower with same leg vaccination. Different leg vaccination produced PD antibody levels quantitatively similar to vaccination with PD alone. We conclude that mixing PD and OMP26 into a single vaccine formulation requires further formulation studies.

Haemophilus influenzae type f in the post-Haemophilus influenzae type b vaccination era: a systematic review

Since the introduction of Haemophilus influenzae (Hi) serotype b (Hib) vaccination, reports of increasing incidence rates of non-Hib serotypes have emerged. A systematic review was performed to investigate whether the Hi serotype f (Hif) incidence rate has increased globally and to describe its associated disease burden. In the post-Hib vaccine era, evidence shows that the incidence rate of Hif infection is increasing worldwide. In total 94 studies including 2 701 patients reported Hif infections. The estimated pooled incidence rate of Hif infection was 0.15/100 000 population per year (range: 0.05–0.40/100 000), with a median case fatality ratio of 14.3 %. Invasive infections most frequently presented as pneumonia (45 %), septicaemia (34 %) and meningitis (20 %). Of 191 Hif isolates, 87 % were ampicillin-susceptible. Multi-locus sequence typing revealed that Hif were relatively clonal, with the majority belonging to clonal complex 124. Hif causes invasive infections of significant variance in both severity and presentation. Globally, the Hif population shows little genetic variability and currently appears to possess low resistance to antimicrobials.

Lipidation of Haemophilus influenzae Antigens P6 and OMP26 Improves Immunogenicity and Protection against Nasopharyngeal Colonization and Ear Infection

Nontypeable Haemophilus influenzae (NTHi) causes respiratory infections that lead to high morbidity and mortality worldwide, encouraging development of effective vaccines. To achieve a protective impact on nasopharyngeal (NP) colonization by NTHi, enhanced immunogenicity beyond that achievable with recombinant-protein antigens is likely to be necessary. Adding a lipid moiety to a recombinant protein would enhance immunogenicity through Toll-like receptor 2 signaling of antigen-presenting cells and Th17 cell response in the nasal-associated lymphoid tissue (NALT). We investigated effects of lipidation (L) of recombinant proteins P6 and OMP26 compared to nonlipidated (NL) P6 and OMP26 and as fusion constructs (L-OMP26ϕNL-P6 and L-P6ϕNL-OMP26) in a mouse model. After intraperitoneal or intranasal vaccination, antibody responses were compared and protection from NP colonization and middle ear infection were assessed. L-P6 and L-OMP26 induced approximately 10- to 100-fold-higher IgG antibody levels than NL-P6 and NL-OMP26. Fusion constructs significantly increased IgG antibody to both target proteins, even though only one of the proteins was lipidated. NP colonization and middle ear bullae NTHi density was 1 to 4 logs lower following vaccination with L-P6 and L-OMP26 than with NL-P6 and NL-OMP26. Fusion constructs also resulted in a 1- to 3-log-lower NTHi density following vaccination. NALT cells from mice vaccinated with lipidated protein constructs had higher levels of interleukin-17 (IL-17), IL-22, and CD4⁺ T-cell memory. Passive transfer of sera from L-OMP26ϕNL-P6-vaccinated mice to recipient infant mice reduced NP colonization and ear bulla NTHi density. We conclude that L-P6, L-OMP26, and fusion constructs generate enhanced antibody responses and protection from NP colonization and middle ear infection by NTHi in mice.

Microbiology and Treatment Outcomes of Community-Acquired Hematogenous Osteoarticular Infections in Infants ≤12 Months of Age

We investigated the microbiology, management, and orthopedic outcomes of osteoarticular infections in infants age ≤1 year at our institution. Among 87 patients, Staphylococcus aureus was the most common pathogen (44.8%), followed by group B Streptococcus. Twenty-nine patients (33%), with a median age of 9.2 months, were transitioned to oral antibiotic therapy after ≤14 days of parenteral therapy; orthopedic outcomes were similar to those with prolonged parenteral therapy.

Environmental protection based on the nanobiosensing of bacterial lipopolysaccharides (LPSs): material and method overview

Lipopolysaccharide (LPS) or endotoxin control is critical for environmental and healthcare issues. LPSs are responsible for several infections, including septic and shock sepsis, and are found in water samples. Accurate and specific diagnosis of endotoxin is one of the most challenging issues in medical bacteriology. Enzyme-linked immunosorbent assay (ELISA), plating and culture-based methods, and Limulus amebocyte lysate (LAL) assay are the conventional techniques in quantifying LPS in research and medical laboratories. However, these methods have been restricted due to their disadvantages, such as low sensitivity and time-consuming and complicated procedures. Therefore, the development of new and advanced methods is demanding, particularly in the biological and medical fields. Biosensor technology is an innovative method that developed extensively in the past decade. Biosensors are classified based on the type of transducer and bioreceptor. So in this review, various types of biosensors, such as optical (fluorescence, SERS, FRET, and SPR), electrochemical, photoelectrochemical, and electrochemiluminescence, on the biosensing of LPs were investigated. Also, the critical role of advanced nanomaterials on the performance of the above-mentioned biosensors is discussed. In addition, the application of different labels on the efficient usage of biosensors for LPS is surveyed comprehensively. Also, various bio-elements (aptamer, DNA, miRNA, peptide, enzyme, antibody, etc.) on the structure of the LPS biosensor are investigated. Finally, bio-analytical parameters that affect the performance of LPS biosensors are surveyed.

Lipopolysaccharide (LPS) or endotoxin control is critical for environmental and healthcare issues.

Molecular Epidemiology of Contemporary Invasive Haemophilus influenzae Isolates in Texas Children

Although vaccination has reduced the incidence of Haemophilus influenzae type b, nontypeable H. influenzae and other encapsulated types remain a health threat. Little is known regarding the contemporary molecular epidemiology of these organisms. We conducted multilocus sequence typing on invasive H. influenzae during a period of increasing incidence.

Haemophilus influenzae Serotype a (Hia) Carriage in a Small Alaska Community After a Cluster of Invasive Hia Disease, 2018

BACKGROUND

Between May and July 2018, 4 Haemophilus influenzae serotype a (Hia) infections occurred in a remote Alaska community. We performed a public health response to prevent further illness and understand Hia carriage.

METHODS

We collected oropharyngeal samples community-wide to evaluate baseline carriage. Risk factors were evaluated by interview. We offered prophylactic rifampin to individuals in contact with invasive Hia patients (contacts) and to all children aged <10 years. Oropharyngeal samples were collected again 8 weeks after rifampin distribution. Samples were tested using real-time polymerase chain reaction and culture.

RESULTS

At baseline, 4 of 27 (14.8%) contacts and 7 of 364 (1.9%) noncontacts (P < .01) carried Hia. Contacts aged <10 years were more likely to carry Hia at any timepoint (11/18 [61%]) compared to contacts aged ≥10 years (3/34 [8.8%]), noncontacts aged <10 years (2/139 [1.4%]), and noncontacts ≥10 years (6/276 [2.2%]) (P < .001 for all). Hia carriers were clustered in 9 households (7% of total households). At the household level, carriage was associated with households with ≥1 contact (prevalence ratio [PR], 5.6 [95% confidence interval {CI}, 1.3-21.6]), crowding (PR, 7.7 [95% CI, 1.1-199.5]), and ≥3 tobacco users (PR, 5.0 [95% CI, 1.2-19.6]). Elevated carriage prevalence persisted in contacts compared to noncontacts 8 weeks after rifampin distribution (6/25 [24%] contacts, 2/114 [1.8%] noncontacts; P < .001).

CONCLUSIONS

Hia carriage prevalence was significantly higher among contacts than noncontacts. Rifampin prophylaxis did not result in a reduction of Hia carriage prevalence in this community.

Epidemiology of Invasive Haemophilus influenzae Serotype a Disease-United States, 2008-2017

BACKGROUND

Haemophilus influenzae serotype a (Hia) can cause invasive disease similar to serotype b; no Hia vaccine is available. We describe the epidemiology of invasive Hia disease in the United States overall and specifically in Alaska during 2008-2017.

METHODS

Active population- and laboratory-based surveillance for invasive Hia disease was conducted through Active Bacterial Core surveillance sites and from Alaska statewide invasive bacterial disease surveillance. Sterile-site isolates were serotyped via slide agglutination or real-time polymerase chain reaction. Incidences in cases per 100 000 were calculated.

RESULTS

From 2008 to 2017, an estimated average of 306 invasive Hia disease cases occurred annually in the United States (estimated annual incidence: 0.10); incidence increased by an average of 11.1% annually. Overall, 42.7% of cases were in children aged <5 years (incidence: 0.64), with highest incidence among children aged <1 year (1.60). Case fatality was 7.8% overall and was highest among adults aged ≥65 years (15.1%). Among children aged <5 years, the incidence was 17 times higher among American Indian and Alaska Native (AI/AN) children (8.29) than among children of all other races combined (0.49). In Alaska, incidences among all ages (0.68) and among children aged <1 year (24.73) were nearly 6 and 14 times higher, respectively, than corresponding US incidences. Case fatality in Alaska was 10.2%, and the vast majority (93.9%) of cases occurred among AI/AN.

CONCLUSIONS

Incidence of invasive Hia disease has increased since 2008, with the highest burden among AI/AN children. These data can inform prevention strategies, including Hia vaccine development.

Acute Hematogenous Osteomyelitis in Children: Clinical Presentation and Management

Acute hematogenous osteomyelitis (AHO) is a common invasive infection encountered in the pediatric population. In addition to the acute illness, AHO has the potential to create long-term morbidity and functional limitations. While a number of pathogens may cause AHO, Staphylococcus aureus is the most common organism identified. Despite the frequency of this illness, little high-quality data exist to guide providers in the care of these patients. The literature is reviewed regarding the epidemiology, microbiology and management of AHO in children. A framework for empiric therapy is provided drawing from the available literature and published guidelines.

Clinical characteristics and adverse clinical outcomes of invasive Haemophilus influenzae serotype a cases - United States, 2011-2015

BACKGROUND

Incidence of invasive disease due to H. influenzae serotype a (Hia) increased an average of 13% annually from 2002-2015. We described clinical characteristics and adverse clinical outcomes of U.S. invasive Hia cases detected through multi-state surveillance during 2011-2015.

METHODS

Medical record data were abstracted for cases reported in eight jurisdictions conducting active population- and laboratory-based surveillance for invasive Hia disease across the United States. Isolates from sterile sites were serotyped by real-time polymerase chain reaction. Adverse clinical outcomes were defined as any possible complication of meningitis, bacteremic pneumonia, or bacteremia (including hearing loss, developmental delay, and speech delay, but excluding death), and were assessed at hospital discharge and one-year post-disease onset.

RESULTS

During 2011-2015, 190 Hia cases were reported to the eight participating sites; 169 (88.9%) had data abstracted. Many patients were aged <5 years (42.6%) or ≥65 years (20.7%). Meningitis was the most common clinical presentation among <1 year olds (71.4%); bacteremic pneumonia was the most common presentation among persons aged ≥50 years (78.7%). Overall, 95.9% of patients were hospitalized: among those hospitalized, 47.5% were admitted to an intensive care unit, and 6.2% died during hospitalization. At hospital discharge and one-year post-disease onset, adverse outcomes were identified in 17.7% and 17.8% of patients overall, and in 43.9% and 48.5% of patients with meningitis (primarily children).

CONCLUSIONS

Hia infection can cause severe disease requiring hospitalization and may also cause short- and long-term adverse clinical outcomes, especially among children. Novel vaccines could prevent morbidity and mortality.

Case Report: Invasive Non Type b Haemophilus influenzae in Immunocompromised Children

Case series

Patients: Male, 2-year-old • Male, 4-year-old • Male, 2-year-old

Final Diagnosis: Immunodeficiency and Hib

Symptoms: Fever • lethargy • reduced food intake

Medication: —

Clinical Procedure: —

Specialty: Immunology