Infection with and Carriage of Mycoplasma pneumoniae in Children

Abstract

"Atypical" pneumonia was described as a distinct and mild form of community-acquired pneumonia (CAP) already before Mycoplasma pneumoniae had been discovered and recognized as its cause. M. pneumoniae is detected in CAP patients most frequently among school-aged children from 5 to 15 years of age, with a decline after adolescence and tapering off in adulthood. Detection rates by polymerase chain reaction (PCR) or serology in children with CAP admitted to the hospital amount 4-39%. Although the infection is generally mild and self-limiting, patients of every age can develop severe or extrapulmonary disease. Recent studies indicate that high rates of healthy children carry M. pneumoniae in the upper respiratory tract and that current diagnostic PCR or serology cannot discriminate between M. pneumoniae infection and carriage. Further, symptoms and radiologic features are not specific for M. pneumoniae infection. Thus, patients may be unnecessarily treated with antimicrobials against M. pneumoniae. Macrolides are the first-line antibiotics for this entity in children younger than 8 years of age. Overall macrolides are extensively used worldwide, and this has led to the emergence of macrolide-resistant M. pneumoniae, which may be associated with severe clinical features and more extrapulmonary complications. This review focuses on the characteristics of M. pneumoniae infections in children, and exemplifies that simple clinical decision rules may help identifying children at high risk for CAP due to M. pneumoniae. This may aid physicians in prescribing appropriate first-line antibiotics, since current diagnostic tests for M. pneumoniae infection are not reliably predictive.

Keywords: Mycoplasma pneumoniae; carriage; children; diagnosis; pneumonia.

FIGURE 1

M. pneumoniae morphology in vitro. Scanning electron micrograph of M. pneumoniae strain Mac (subtype 2).

FIGURE 2

Detection of M. pneumoniae in community-acquired pneumonia (CAP) according to age group. Infection was diagnosed by culture of respiratory specimens and/or a fourfold titer rise in complement fixation test (CFT). Adapted with permission from Foy et al. (1979).

FIGURE 3

M. pneumoniae-associated mucositis (MPAM). Erosive oral lesions limited to the mucosa in this form of MPAM in a 24-year-old woman. Reprinted with permission from Meyer Sauteur et al. (2012).

FIGURE 4

M. pneumoniae-associated encephalitis. Axial cranial magnetic resonance imaging (MRI) in two children with encephalitis during M. pneumoniae infection: (A) 5-year-old boy with hyperintensity and generalized edema of the right temporal lobe [T1 weight MRI; patient 1 published in Meyer Sauteur et al. (2016)]. (B) 9-year-old boy with generalized edema of crus posterior of capsula interna [T2 weight MRI; reprinted with permission from Meyer Sauteur et al. (2014c)].

FIGURE 5

A fast-and-frugal clinical decision tree for ruling out M. pneumoniae infection in children with community-acquired pneumonia (CAP). Clinical features are considered sequentially, with a possible stop decision after each question. Abbreviations: AR, absolute risk; CI, confidence interval. Adapted from Fischer et al. (2002).

FIGURE 6

Worldwide macrolide-resistant M. pneumoniae (MRMP) rates. Actual MRMP rates are punctually depicted in pie charts (in black) over the world map. Asia: Japan (2011): 87% (176/202) (Okada et al., 2012), South Korea (2011): 63% (44/70) (Hong et al., 2013), China (2012): 97% (31/32) (Zhao et al., 2013), Israel (2010): 30% (9/30) (Averbuch et al., 2011); North America: U.S. (2012–2014): 13% (12/91) (Zheng et al., 2015), Canada (2010–2012): 12% (11/91) (Eshaghi et al., 2013); Europe: The Netherlands (1997–2008): 0% (0/114) (Spuesens et al., 2012), Germany (2003–2008): 1% (2/167) (Dumke et al., 2010), France (2005–2007): 10% (5/51) (Peuchant et al., 2009), Italy (2010): 26% (11/43) (Chironna et al., 2011), Scotland (2010–2011): 19% (6/32) (Ferguson et al., 2013), Switzerland (2011–2013): 2% (1/50) (Meyer Sauteur et al., 2014a), England and Wales (2014–2015): 9% (4/43) (Brown et al., 2015).