Paediatric invasive Haemophilus influenzae in Queensland, Australia, 2002-2011: Young Indigenous children remain at highest risk

[Association of Haemophilus influenzae infection with environmental and climatic factors in Suzhou, China]

OBJECTIVES

To investigate the epidemiological characteristics of respiratory Haemophilus influenzae (HI) infection in children in Suzhou, China and its association with climatic factors and air pollutants.

METHODS

The data on air pollutants and climatic factors in Suzhou from January 2016 to December 2019 were collected. Respiratory secretions were collected from 7 940 children with acute respiratory infection who were hospitalized during this period, and bacterial culture results were analyzed for the detection of HI. A stepwise regression analysis was used to investigate the association of HI detection rate with air pollutants (PM2.5, PM10, NO2, SO2, CO, and O3) and climatic factors (monthly mean temperature, monthly mean humidity, monthly total rainfall, monthly total sunshine duration, and monthly mean wind speed).

RESULTS

In 2016-2019, the 4-year overall detection rate of HI was 9.26% (735/7 940) among the children in Suzhou. The children aged <1 year and 1-<3 years had a significantly higher HI detection rate than those aged ≥3 years (P<0.01). The detection rate of HI in spring was significantly higher than that in the other three seasons, and the detection rate of HI in autumn was significantly lower than that in the other three seasons (P<0.001). The multiple linear regression analysis showed that PM10 and monthly mean wind speed were independent risk factors for the detection rate of HI: the detection rate of HI was increased by 0.86% for every 10 µg/m3 increase in the concentration of PM10 and was increased by 5.64% for every 1 m/s increase in monthly mean wind speed. Air pollutants and climatic factors had a lag effect on the detection rate of HI.

CONCLUSIONS

HI is an important pathogen for acute respiratory infection in children in Suzhou and is prevalent in spring. PM10 and monthly mean wind speed are independent risk factors for the detection rate of HI.

Naturally acquired antibody against Haemophilus influenzae type a in pediatric saliva

We developed a salivary assay for the detection of naturally acquired IgA antibody against Haemophilus influenzae type a (Hia) capsular polysaccharide in healthy Indigenous children from Northwestern Ontario, Canada. Hia-specific IgA antibody was detected in the saliva of 93% of Indigenous children aged 2-7 years.

Increased Incidence of Invasive Haemophilus influenzae Disease Driven by Non-Type B Isolates in Ontario, Canada, 2014 to 2018

Haemophilus influenzae can cause serious invasive disease. We report the epidemiology and antimicrobial susceptibility of invasive H. influenzae in Ontario, Canada, from 2014 to 2018 from laboratory-based data. Blood was the most common specimen source (89.5%). Consistent with widespread vaccination against serotype b (Hib), the incidence of Hib in Ontario remained low (0.04 cases per 100,000 population). H. influenzae disease primarily afflicted those <1 and ≥65 years of age. From 2014 to 2018, cases of invasive H. influenzae increased 5.6%, from 1.67 to 2.06 cases per 100,000 population, the majority of which were attributed to a 7.6% increase in the incidence of H. influenzae in those ≥65 years old. H. influenzae disease was primarily caused by nontypeable H. influenzae (NTHi) (74.2%) and, to a much lesser extent, serotype a (Hia) (8.9%) and serotype f (Hif) (10.2%). Serotype-dependent trends in antimicrobial susceptibility were observed. Hia and Hif isolates were predominantly susceptible to all antibiotics tested, while 27.2% of NTHi isolates were nonsusceptible to ampicillin. Resistance to ceftriaxone and meropenem, first-line antibiotics for invasive disease treatment, was nonexistent. The incidence of invasive H. influenzae in Ontario is increasing. The incidence and antimicrobial susceptibility of all serotypes and nontypeable H. influenzae should be monitored. IMPORTANCE H. influenzae can cause serious invasive, life-threatening disease and is considered 1 of 12 priority pathogens by the World Health Organization. Widespread vaccination against H. influenzae serotype b (Hib) has resulted in very low incidence of Hib in Ontario and other regions that have vaccination programs. However, the epidemiology of non-Hib serotypes and nontypeable H. influenzae (NTHi) remains poorly understood. Here, we describe the epidemiology of all invasive H. influenzae isolates (N = 1,338) received by our laboratory over the 5-year period and report on the antimicrobial susceptibility patterns by serotype. Overall, we observed an increase in the incidence of invasive disease over the study period, primarily driven by NTHi. Serotype-dependent trends in antimicrobial susceptibility were also observed. This work contributes to the global understanding of H. influenzae epidemiology and antimicrobial resistance and is additionally important for further vaccine planning initiatives.

Haemophilus influenzae type b disease in the era of conjugate vaccines: critical factors for successful eradication

INTRODUCTION

Prior to implementation of Haemophilus influenzae type b (Hib)-conjugate vaccination programs in the 1990s, Hib was the commonest cause of bacterial meningitis in children aged <5 years. While the burden of all Hib disease has significantly decreased in the post-vaccination era, Hib still accounted for >29,000 deaths worldwide in children aged <5 years in 2015.

AREAS COVERED

We reviewed literature data on the most widely used Hib vaccines and vaccination strategies which led to the global prevention and control of Hib disease and aim to highlight important factors for continued disease control and elimination in the future.

EXPERT COMMENTARY

More than 90% of countries worldwide have implemented Hib-conjugate vaccination in their national immunization programs. Vaccines containing Hib polyribosylribitol phosphate (PRP) conjugated with tetanus toxoid (Hib-TT) are the most commonly used. Neisseria meningitidis outer membrane protein complex of PRP (Hib-OMP) is also used. Although the kinetics of the immune response varies with Hib vaccine and schedule used, high control of Hib disease was observed in all settings/scenarios. Further improving global Hib vaccination coverage may result in disease elimination. Plain language summary What is the context? Haemophilus influenzae is causing a variety of diseases, from otitis media and sinusitis to invasive disease (e.g. meningitis and pneumonia). H. influenzae type b (Hib) was the most common cause of bacterial meningitis in children <5 years of age, and especially among <2-year-olds. Even with appropriate treatment, up to 40% of children with bacterial meningitis can suffer permanent disabilities and up to 5% will die. The development of vaccines to protect against Hib disease has started in the late 1970s and has culminated with the licensure of 4 Hib conjugate vaccines, of which 2 are currently widely used. What is new? In this review, we gathered evidence on the different Hib vaccines and vaccination strategies that have contributed to the global prevention and control of Hib disease. The review indicates: the incidence of Hib disease has decreased considerably due to the introduction of Hib vaccines in national immunization programs worldwide. However, Hib disease is not yet completely eradicated. the vaccines currently used offer protection against Hib over long periods of time. carriage of the pathogen by healthy individuals seem to be less frequent, but data are still needed to fully evaluate the impact of vaccination. other H. influenzae types are now more frequent. Why is this important? Despite the huge success of Hib vaccination, continuous surveillance is needed to anticipate potential re-emergences and devise the best strategies for prevention and control of disease. Hib vaccination should be considered in the few countries who have not yet implemented it, to decrease associated morbidity and mortality.

Nontypable Haemophilus influenzae Septicemia and Urinary Tract Infection Associated with Renal Stone Disease

Introduction:

Haemophilus influenzae commonly causes upper respiratory tract infections and has only rarely been reported etiology of urinary tract infections. Since the introduction of the Haemophilus influenzae b (Hib) vaccine, non-typable haemophilus species now cause the majority of invasive disease in Europe.

Case Report:

We report a case of an adult man with non-typable Haemophilus influenzae septicemia, urinary tract infection and bilateral renal stone disease. The patient presented with right sided flank pain and a CT scan showed bilateral renal stones and a right sided ureteral stone causing obstruction.

Results and Discussion:

Haemophilus influenzae was identified in blood and urine and despite a tendency of increasing antibiotic resistance among Haemophilus influenzae, our strain was susceptible to all antibiotics tested. Treatment consisted of 3 days of intravenous cefuroxime, insertion of a right sided JJ ureteric stent and 5 days of peroral ciprofloxacin after discharge. Physicians and microbiologists should be aware of Haemophilus influenzae as a possible urinary tract pathogen, especially when urinary tract abnormalities are present, and take the risk of antibiotic resistance into consideration at initial treatment.

Context-sensitive antibiotic optimization: a qualitative interviews study of a remote Australian hospital setting

BACKGROUND

Antibiotic optimization is an urgent international issue. Regulatory frameworks, including the requirement to have a functioning antimicrobial stewardship (AMS) programme, are now ubiquitous across the hospital sector nationally and internationally. However, healthcare is ultimately delivered in a diverse range of institutional settings and social contexts. There is emerging evidence that implementation of antibiotic optimization strategies may be inappropriate or even counterproductive to attempts to optimize in atypical healthcare settings.

AIM

To document the experiences and perspectives of clinical staff in a remote healthcare setting in Australia with respect to antimicrobial use, and strategies for optimization in that environment.

METHODS

Semi-structured qualitative interviews were conducted with 30 healthcare professionals, including doctors, nurses and pharmacists, from a remote hospital in Queensland, Australia.

FINDINGS

Four themes were identified from the analysis as key challenges to antibiotic optimization: (i) AMS as externally driven, and local knowledge sidelined; (ii) perceptions of heightened local population risks, treatment failure and the subsequent pressure to over-use of antimicrobials; (iii) interprofessional relationship dynamics including medical hierarchical structures perceived as a barrier to AMS; (iv) a clinical workforce dominated by transient locum staff and other process issues were perceived as significant barriers.

CONCLUSION

The perceptions of healthcare professionals in this site lead to the conclusion that antimicrobial regulations and practice improvement strategies more generally are unlikely to succeed if they fail to accommodate and respect the context of care, the resource and structural constraints of the setting, and the specificities of particular populations (and subsequent clinical 'know-how').