Mycoplasma pneumoniae Infections: Pathogenesis and Vaccine Development

Abstract

Mycoplasma pneumoniae is a major causative agent of community-acquired pneumonia which can lead to both acute upper and lower respiratory tract inflammation, and extrapulmonary syndromes. Refractory pneumonia caused by M. pneumonia can be life-threatening, especially in infants and the elderly. Here, based on a comprehensive review of the scientific literature related to the respective area, we summarize the virulence factors of M. pneumoniae and the major pathogenic mechanisms mediated by the pathogen: adhesion to host cells, direct cytotoxicity against host cells, inflammatory response-induced immune injury, and immune evasion. The increasing rate of macrolide-resistant strains and the harmful side effects of other sensitive antibiotics (e.g., respiratory quinolones and tetracyclines) in young children make it difficult to treat, and increase the health risk or re-infections. Hence, there is an urgent need for development of an effective vaccine to prevent M. pneumoniae infections in children. Various types of M. pneumoniae vaccines have been reported, including whole-cell vaccines (inactivated and live-attenuated vaccines), subunit vaccines (involving M. pneumoniae protein P1, protein P30, protein P116 and CARDS toxin) and DNA vaccines. This narrative review summarizes the key pathogenic mechanisms underlying M. pneumoniae infection and highlights the relevant vaccines that have been developed and their reported effectiveness.

Refractory Mycoplasma pneumoniae Pneumonia in Children: Early Recognition and Management

“…Once infected with the host, M. pneumoniae mainly adheres to ciliary cells of the mucosal epithelium, and close contact and material exchange between the bacterial membrane and the host cell provide an important material basis for its growth and proliferation. Bacterial cellular components such as glycolipids and capsular polysaccharides [ 34 ], virulence factors such as community-acquired respiratory distress syndrome (CARDS) toxin [ 35 ] and hydrogen sulfide, alanine, and pyruvate producing enzyme (HapE) [ 36 ], toxic metabolites such as hydrogen peroxide [ 37 ] and H 2 S [ 38 ], and nuclease [ 39 ], among others, are the main mechanisms for tissue damage. They also inhibit host clearance and promote immune escape [ 40 ].…”

Geraniol relieves mycoplasma pneumonia infection‐induced lung injury in mice through the regulation of ERK/JNK and NF‐κB signaling pathways

“…[ 8 ] Followed by the infection of M. pneumoniae , the inflammatory reactions generated by lymphocytes, macrophages, and neutrophils penetrating around the bronchial and alveolar vessels is the main pathological event of M. pneumoniae provoked pneumonia auto‐immunity. [ 9 ] Subsequently, M. pneumoniae occupies the respiratory tract, which generates complex auto‐immune reactions. Neutrophils promptly shift to the infection site and get activated, and the over inflammatory responses are produced by the generation of several specific proteases.…”

The immunodominant protein P116 extracts cholesterol and other essential lipids

“…Mycoplasma pneumoniae is a facultative intracellular human pathogen causing community-acquired pneumonia that can manifest severe systemic effects 1 . Unlike other respiratory pathogens, M. pneumoniae has no approved vaccine 2 . Mycoplasmas lack a cell wall and have the smallest known genomes 3 .…”