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.

Differences in clinical characteristics and outcomes between COVID-19 and influenza in critically ill adult patients: a national database study

OBJECTIVE

Prior to the coronavirus disease 2019 (COVID-19) pandemic, influenza was the most frequent cause of viral respiratory pneumonia requiring intensive care unit (ICU) admission. Few studies have compared the characteristics and outcomes of critically ill patients with COVID-19 and influenza.

METHODS

This was a French nationwide study comparing COVID-19 (March 1, 2020-June 30, 2021) and influenza patients (January 1, 2014-December 31, 2019) admitted to an ICU during pre-vaccination era. Primary outcome was in-hospital death. Secondary outcome was need for mechanical ventilation.

RESULTS

105,979 COVID-19 patients were compared to 18,763 influenza patients. Critically ill patients with COVID-19 were more likely to be men with more comorbidities. Patients with influenza required more invasive mechanical ventilation (47 vs. 34%, p<0·001), vasopressors (40% vs. 27, p<0·001) and renal-replacement therapy (22 vs. 7%, p<0·001). Hospital mortality was 25 and 21% (p<0·001) in patients with COVID-19 and influenza, respectively. In the subgroup of patients receiving invasive mechanical ventilation, ICU length of stay was significantly longer in patients with COVID-19 (18 [10-32] vs. 15 [8-26] days, p<0·001). Adjusting for age, gender, comorbidities, and modified SAPS II score, in-hospital death was higher in COVID-19 patients (adjusted sub-distribution hazard ratio [aSHR]=1.69; 95%CI=1.63-1.75) compared with influenza patients. COVID-19 was also associated with less invasive mechanical ventilation (aSHR=0.87; 95%CI=0.85-0.89) and a higher likelihood of death without invasive mechanical ventilation (aSHR=2.40; 95%CI=2.24-2.57).

CONCLUSION

Despite younger age and lower SAPS II score, critically ill COVID-19 patients had a longer hospital stay and higher mortality than patients with influenza.

The Spanish Flu

The Spanish flu occurred at the end of the First World War, in disastrous epidemiological conditions on populations exhausted by four years of war. At that time, there were no vaccines, no antibiotics, no oxygen and no resuscitation. It was even thought that the infectious agent was a bacterium. Humanity was poorly equipped to fight against a pandemic that caused 50-100 million deaths. The first palpable signs of the outbreak were the rapidly spreading multiple epidemics among young recruits in the American military training camps in March 1918. The flu then spread to the civilian populations and circled the globe twice, sparing no country, even the most remote islands, in tropical as well as polar climates, evolving in successive waves up until April 1919. The first was mild (lethality 0.21%), the second was lethal (lethality 2-4%), and during the third wave, lethality declined (1%), after which the flu became seasonal, with low lethality (0.1%). Between 20 and 40 years of age, patients often died within a few days of pneumonia, with respiratory distress leading to cyanosis, frequently associated with bacterial superinfection. The influenza virus, Myxovirus influenzae, was first discovered in 1931 by Richard Shope in pigs, and then in 1933 by Wilson Smith, Patrick Laidlaw and Christopher Andrews in humans during a seasonal influenza epidemic in London. In 1943, it was first observed under the electron microscope. Hemagglutinin and neuraminidase, the two main virulence factors, were discovered in the 1940s by George Hirst and Alfred Gottschalk. An RNA virus composed of 13,500 nucleotides in eight segments, it was initially sequenced in the 1980s, when Jeffrey Taubenberger determined the complete nucleotide sequence of the 1918 virus from lung tissue samples from patients who died of influenza. The 1918 H1N1 virus was found to have originated in birds. In 2005, it was successfully resuscitated in cell culture. It is 40,000 times more virulent in primates than the seasonal H1N1 virus. The lethality of the second wave could have been due to mutations in the hemagglutinin H1 gene, which would have resulted in a stronger affinity for α,2-6 galactose sialic acids, the virus' receptors on human epithelial cells. That said, the origin of the Spanish flu virus remains controversial. It probably emerged and circulated in the population before March 1918 in America, although European origin has also been evoked. The high mortality in the 20-40 age group remains an enigma. Some experts point to reduced immune response in patients previously exposed to related viral hemagglutinins during the 1889 pandemic. In any event, even though it concerns a markedly different virus, the history of the Spanish flu sheds light on the difficulties of management during today's pandemic.

Disseminated "Haemophilus quentini" infection in a patient with multiple myeloma - a case report and review of the literature

We describe a case report of a 56-year-old male with undiagnosed multiple myeloma who had severe sepsis associated with pneumonia, meningitis, polyarthritis, and osteomyelitis related to invasive "Haemophilus quentini" infection. The genus was misidentified as H. influenzae by the common bacterial identification systems including newly introduced syndromic PCR-based methods. We review the epidemiological, clinical, and laboratory aspects of this rare, cryptic species of Haemophilus.

Lactobacillus paracasei feeding improves the control of secondary experimental meningococcal infection in flu-infected mice

BACKGROUND

The use of probiotics to improve anti-microbial defence, such as for influenza infections, is increasingly recommended. However, no data are available on the effect of probiotics on flu-associated secondary bacterial infections. There is strong evidence of a spatiotemporal association between influenza virus infection and invasive Neisseria meningitidis. We thus investigated the effect of feeding mice Lactobacillus paracasei CNCM I-1518 in a mouse model of sequential influenza-meningococcal infection.

METHODS

We intranasally infected BALB/c mice with a strain of influenza A virus (IAV) H3N2 that was first adapted to mice. Seven days later, a secondary bacterial infection was induced by intranasal administration of bioluminescent N. meningitidis. During the experiment, mice orally received either L. paracasei CNCM I-1518 or PBS as a control. The effect of L. paracasei administration on secondary bacterial infection by N. meningitidis was evaluated.

RESULTS

Oral consumption of L. paracasei CNCM I-1518 reduced the weight loss of infected mice and lowered the bioluminescent signal of infecting meningococci. This improvement was associated with higher recruitment of inflammatory myeloid cells, such as interstitial monocytes and dendritic cells, to the lungs.

CONCLUSIONS

Our data highlight the role of the gut-lung axis. L. paracasei CNCM I-1518 may boost the defence against IAV infection and secondary bacterial infection, which should be further studied and validated in clinical trials.