The influenza virus is one of the major threats to the health of the population all over the world. It is considered to be one of the infections with the highest potential for mutation as it constantly evolves and adapts to living in a human body. The virus is also among the most contagious diseases with high risks of lethality and severe complications, capable of damaging many organs, including lungs, heart, and kidneys. One of the common consequences of influenza is virus-induced pneumonia, which can be aggravated by bacteria, such as Klebsiella, which require specific treatment and often lead to fatal outcome.
Seasonal influenza viruses are considered to be among the most serious illnesses, presenting a threat to the human population. According to the statistics, each year, it infects 5–15% of people all over the world and results in approximately 500,000 deaths (Petrova and Russell). The disease is regarded as extremely contagious as it can be transmitted from one person to another through both direct contacts and respiratory droplets. Influenza viruses are a part of the Orthomyxoviridae family of viruses, characterized by “negative-sense, single-stranded, segmented RNA genomes” (Petrova and Russell 47). The group is classified into three types: A, B, and C. However, the last one is not dangerous for the population. Influenza A is transmitted to humans from birds and swine, although, most of its variants do not circulate among people and rarely cause a seasonal epidemic. Influenza B is divided into two major subtypes, B/Victoria and B/Yamagata (Petrova and Russell). Their constant mutations make the process of protecting the population difficult for scientists all over the world.
The genomes of the influenza A and B virus have a compound structure. They are composed of “eight viral ribonucleoprotein (vRNP) complexes, encoding at least ten proteins and multiple polypeptides” (Petrova and Russell 48). According to a study, which quantitatively compared the virus’s viral genetic diversity within and between human hosts, it is the reason for its rapid development (Xue and Bloom). To replicate these microbes use “an RNA-dependent RNA polymerase, which lacks proofreading capability” (Johnson et al. 1). It signifies the occurrence of errors in the genes of the virus, which allows it to mutate. It leads to the appearance of new variants of the same infection, also known as quasispecies (Johnson et al.). With the help of these changes, viruses are capable of adapting to various environmental conditions, which results in the constant circulation of different forms of the same infection.
The potential for rapid development makes influenza viruses A and B dangerous for society. Each year, there are thousands of deaths induced by the disease all over the world. One of the most important reasons for possible complications, which may increase the lethality risks are bacteria, capable of inducing pneumonia in addition to the symptoms caused by the virus. There are numerous organisms with such potential and one of them is Klebsiella, which is typically harmless for individuals. The bacterium was first described by Carl Friedlander in 1882 as an encapsulated, gram-negative, non-motile bacillus found in the environment and was associated with pneumonia in patients suffering from alcohol use disorder or diabetes mellitus (Ashurst and Dawson). It usually “colonizes human mucosal surfaces of the oropharynx and gastrointestinal (GI) tract” (Ashurst and Dawson 1). In the organism, the bacterium shows high levels of virulence and antibiotic resistance, which make it difficult to treat. Today, it is also considered to be the reason for most cases of hospital-acquired pneumonia, which leads to lethality in more than 50% of the cases.
Klebsiella pneumonia is a part of the Enterobacteriaceae family, which is characterized by a few key factors defining its virulence. The first aspect allowing the bacterium to remain powerful is a polysaccharide capsule of the organism as it helps to “evade opsonophagocytosis and serum killing by the host organism” (Ashurst and Dawson 4). A second factor is lipopolysaccharides, which cover the surface of the bacterium, as “the sensing of lipopolysaccharides releases an inflammatory cascade in the host organism” and often becomes a reason for such complications as sepsis and septic shock (Ashurst and Dawson 4). Fimbriae is another virulence factor, contributing to the attachment of the organism to the victim’s cells as well as siderophores, which are to cause infection in hosts by acquiring iron from them.
The Klebsiella bacterium is one of the organisms, which often lives in the human body for a long time. According to the statistics, it is found in stool among 5% to 38% of the general population and in the nasopharynx among 1% to 6% (Ashurst and Dawson). Pneumonia induced by the Klebsiella bacterium is divided into two groups: community-acquired and hospital-acquired. In developed countries, only approximately 3% to 5% of community-acquired pneumonia is triggered by this microbe, while it is a reason for 11.8% of all hospital-acquired pneumonia in the world (Ashurst and Dawson). Among the key factors, defining the risks of an individual to acquire pneumonia induced by the Klebsiella bacterium, are admission to intensive care, poor infection control techniques, prolonged use of invasive devices and broad-spectrum antibiotics, alcohol abuse, and diabetes.
The symptoms of the disease induced by the Klebsiella bacterium are common for any type of community-acquired pneumonia. People with this condition may show such signs as a cough, chest pains, fever, and shortness of breath. The difference from other variants of the illness can be found in the sputum, which in these cases is often described as “currant jelly” (Ashurst and Dawson). It can be explained by a significant influence of the bacterium on the surrounding tissues, which results in their inflammation and necrosis. This type of pneumonia typically affects the upper lobes, showing “unilateral signs of consolidation, such as crepitation, bronchial breathing, and increased vocal resonance” (Ashurst and Dawson 11). In the case of hospital-acquired infections, there is a possibility of revealing such signs as burn sites, wounds, and invasive devices.
To establish the right diagnosis, doctors require laboratory analysis, which can show leukocytosis, proving a patient has a bacterial infection, chest radiograph, and sputum or blood culture analysis. After the cause of pneumonia is found, a 14-day antibiotic therapy with “either a third or fourth-generation cephalosporin or a respiratory quinolone or either of the regimes in conjunction with an aminoglycoside” is prescribed to patients (Ashurst and Dawson 15). In case of allergies to penicillin, a patient receives aztreonam or a respiratory quinolone. Nosocomial infections often require a carbapenem as monotherapy as it typically shows low rates of sensitivity. For patients with such complications as empyema, lung abscess, or gangrene, there may be a need for surgical debridement or drainage.
In conclusion, the influenza virus is among the most serious infections around the globe, which leads to thousands of deaths each year. It is extremely virulent due to a set of factors, which contribute to its evolution, making it impossible to eliminate it. The disease remains dangerous for people all over the world due to its constant mutation producing new variants of the virus. High lethality rates are typically connected with complications, which can be triggered in the human body as a result of the illness. Among the factors, capable of worsening the prognosis, are bacteria, such as Klebsiella, causing severe cases of pneumonia. The disease is difficult to diagnose and requires complex therapy with antibiotics, and surgery in severe cases. The bacterium remains one of the most common reasons for death in hospitals all over the world.
Works Cited
Ashurst, John V., and Adam Dawson. Klebsiella Pneumonia. StatPearls, 2021. Web.
Johnson, Katherine E. E. et al. Getting the Flu: 5 Key Facts about Influenza Virus Evolution. PLoS Pathogens, vol. 13, no. 8. Web.
Petrova, Velislava N., and Colin A. Russell. The Evolution of Seasonal Influenza Viruses. Nature Reviews Microbiology, vol. 16, 2018, pp. 47-60. Web.
Xue, Katherine S., and Jesse D. Bloom. Linking Influenza Virus Evolution Within and Between Human Hosts. Virus Evolution, vol. 6, no. 1, 2020. Web.