Megapneumonia Coinfection: pneumococcus, Mycoplasma pneumoniae, and Metapneumovirus

Molecular and clinical characteristics of severe Mycoplasma pneumoniae pneumonia in children

OBJECTIVES

To analyze the molecular and the clinical characteristics of Mycoplasma pneumoniae (Mp) pneumonia (MPP) and to explore the related factors predicting severe MPP (SMPP).

METHODS

A total of 423 pediatric cases of MPP were retrospectively analyzed, in 2013-2017, in Beijing, China. Clinical information was collected from the medical records. Mp-positive specimens were characterized using P1 typing and multiple locus variable-number tandem repeat analysis (MLVA). The macrolide resistance-associated mutations were also detected.

RESULTS

The predominant genotype was P1-1 (88.2%) and M4-5-7-2 (87.5%), whereas percentages of type P1-2 and M3-5-6-2 increased across the 5-year period. The mutation rate of genotype M4-5-7-2 (365/370, 98.6%) was significantly higher than that of the genotype M3-5-6-2 (15/48, 32.25%; P = 0.000). Overall, 180 (42.6%) of the 423 Mp-positive patients were coinfected with other pathogens. Respiratory syncytial virus coinfection (24/180, 13.3%) was more common in cases typed M3-5-6-2 (4/23, 17.4%) than that of M4-5-7-2 (20/155, 12.9%; P = 0.038). Pleural effusion accounted for 52.6% (169/321) of the observed complications. In the mono-infection cases, cases typed M3-5-6-2 (56%, 14/25) were significantly (P = 0.020) associated with pleural effusion compared with those typed M4-5-7-2 (32.6%, 70/215); 84% (21/25) of specimens typed M3-5-6-2 were diagnosed as SMPP, whereas 63.7% (137/215) of specimens typed M4-5-7-2 were diagnosed as SMPP (P = 0.043).

CONCLUSIONS

In our study, we proposed for the first time that the mono-infection patients with Mp typed M3-5-6-2 appear to have a higher risk for progressing to SMPP. MLVA typing can provide hints on the clinical characteristics of Mpp.

Change in Pneumococcus Serotypes but not Mortality or Morbidity in Pre- and Post-13-Valent Polysaccharide Conjugate Vaccine Era: Epidemiology in a Pediatric Intensive Care Unit over 10 Years

AIM

Pneumococcus is a common commensal and an important pathogen among children for which immunization is available. Some serotypes occasionally cause severe pneumococcal disease with high mortality and morbidity. We reviewed all pneumococcal serotypes and mortality/morbidity in a pediatric intensive care unit (PICU) following universal pneumococcal conjugate vaccine (PCV) immunization.

METHODS

A 13-valent PCV was introduced in the universal immunization program in late 2011 in Hong Kong. We retrospectively reviewed all pneumococcal serotypes in the pre-(2007-11) and post-(2012-16) 13-valent PCV era.

RESULTS

There were 29 (1.9%) PICU patients with pneumococcal isolation, of which 6 died (20% motality). Serogroups 6 and 19 predominated before and Serogroup 3 after 2012. In the post-13-valent PCV era, the prevalence of pneumococcus isolation in PICU was increased from 1 to 2% (p = 0.04); Serogroup 3 was the major serotype of morbidity, despite supposedly under vaccine coverage. The majority of pneumococcus were penicillin-sensitive (94%) in the post 13-valent PCV era. All pneumococcus specimens were sensitive to cefotaxime and vancomycin. Binary logistic regression showed that there were reductions in Serogroup 6 (odds ratio [OR], 0.050; 95% confidence interval [CI], 0.004-0.574; p = 0.016) and Serogroup 19 (odds ratio [OR], 0.105; 95% confidence interval [CI], 0.014-0.786; p = 0.028) but not mortality or morbidity for patients admitted after 2012.

CONCLUSIONS

SPD is associated with significant morbidity and mortality, despite treatment with systemic antibiotics and ICU support. The expanded coverage of 13-valent PCV results in the reduction of Serotypes 6 and 19 but not mortality/morbidity associated with SPD in the setting of a PICU.

Paramyxovirus Infection: Mortality and Morbidity in a Pediatric Intensive Care Unit

OBJECTIVES

We investigated mortality and morbidity of patients admitted to a pediatric intensive care unit (PICU) with paramyxovirus infection.

METHODS

A retrospective study between October 2002 and March 2015 of children with a laboratory-confirmed paramyxovirus infection was included.

RESULTS

In all, 98 (5%) PICU admissions were tested positive to have paramyxovirus infection (respiratory syncytial virus =  66, parainfluenza  =  27 and metapneumovirus  =  5). The majority of admissions were young patients (median age 1.05 years). Bacteremia and bacterial isolation in any site were present in 10% and 28%, respectively; 41% were mechanically ventilated, and 20% received inotropes. The three respiratory viruses caused similar mortality and morbidity in the PICU. Fatality (seven patients) was associated with malignancy, positive bacterial culture in blood, the use of mechanical ventilation, inotrope use, lower blood white cell count and higher C reactive protein (p  =  0.02-0.0005). Backward binary logistic regression for these variables showed bacteremia (odds ratio [OR]: 31.7; 95% CI: 2.3-427.8; p  =  0.009), malignancy (OR: 45.5; 95% CI: 1.4-1467.7; p  =  0.031) and use of inotropes (OR: 15.0; 95% CI: 1.1-196.1; p  =  0.039) were independently associated with non-survival. March and July appeared to be the two peak months for PICU hospitalizations with paramyxovirus infection.

CONCLUSIONS

Infections with paramyxoviruses account for 5% of PICU admissions and significant morbidity. Patient with premorbid history of malignancy and co-morbidity of bacteremia are associated with non-survival. March and July appeared to be the two peak months for PICU admissions with paramyxoviruses.

Insights into the pathogenesis of Mycoplasma pneumoniae (Review)

Mycoplasma are the smallest prokaryotic microbes present in nature. These wall-less, malleable organisms can pass through cell filters, and grow and propagate under cell-free conditions in vitro. Of the pathogenic Mycoplasma Mycoplasma pneumoniae has been examined the most. In addition to primary atypical pneumonia and community-acquired pneumonia with predominantly respiratory symptoms, M. pneumoniae can also induce autoimmune hemolytic anemia and other diseases in the blood, cardiovascular system, gastrointestinal tract and skin, and can induce pericarditis, myocarditis, nephritis and meningitis. The pathogenesis of M. pneumoniae infection is complex and remains to be fully elucidated. The present review aimed to summarize several direct damage mechanisms, including adhesion damage, destruction of membrane fusion, nutrition depletion, invasive damage, toxic damage, inflammatory damage and immune damage. Further investigations are required for determining the detailed pathogenesis of M. pneumoniae.

Typical or atypical pneumonia and severe acute respiratory symptoms in PICU

Background and Aims

Mycoplasma pneumoniae (MP) is a common childhood pathogen associated with atypical pneumonia (AP). It is often a mild disease and seldom results in paediatric intensive care (PICU) admission. In 2003, World Health Organization (WHO) coined the word SARS (severe acute respiratory syndrome) in patients with severe acute respiratory symptoms (sars) for an outbreak of AP in Hong Kong due to a novel coronavirus. In 2012, another outbreak of coronavirus AP occurred in the Middle East. Confusing case definitions such as MERS (Middle East respiratory syndrome) and SARI (severe acute respiratory infections) were coined. This paper aims to present a case of MP with sars, ARDS, pneumonia and pleural effusion during the MERS epidemics, and review the incidence and mortality of severe AP with MP.

Methods

We presented a case of MP with sars, acute respiratory distress syndrome (ARDS), pneumonia and pleural effusion during the MERS epidemics, and performed a literature review on the incidence and mortality of severe AP with MP requiring PICU care.

Results

In early 2013, an 11‐year‐old girl presented with sars, ARDS (acute respiratory distress syndrome), right‐sided pneumonia and pleural effusion. She was treated with multiple antibiotics. Streptococcus pneumoniae was not isolated in this girl with ‘typical’ pneumonia by symptomatology and chest radiography, but tracheal aspirate identified MP instead. The respiratory equations are computed with PaO₂/FiO₂ consistent with severe lung injury. Literature on the incidence and mortality of severe AP with MP requiring PICU care is reviewed. Six, 165 and 293 articles were found when PubMed (a service of the U.S. National Library of Medicine) was searched for the terms ‘mycoplasma’ and ‘ICU’, ‘mycoplasma’ and ‘mortality’, and ‘mycoplasma' and ‘severe’. Mortality and PICU admission associated with MP is general low and rarely reported. Experimental and clinical studies have suggested that the pathogenesis of lung injuries in MP infection is associated with a cell‐mediated immune reaction, and high responsiveness to corticosteroid therapy has been reported especially for severe disease. Management of severe mycoplasma infection in the PICU includes general cardiopulmonary support and specific antimicrobial treatment. Macrolide resistance genotypes have been detected.

Conclusion

We urge health organizations to refrain from the temptation of coining unnecessary new terminology to describe essentially the same conditions each and every time when outbreaks of AP occur.

Cardiopulmonary morbidity of streptococcal infections in a PICU

AIM

The streptococci are important bacteria that cause serious childhood infections. We investigated cardiopulmonary morbidity associated with streptococcal infection and pediatric intensive care unit (PICU) admission.

METHODS

A retrospective study between 2002 and 2013 of all children with a laboratory isolation of streptococcus.

RESULTS

There were 40 (2.3%) PICU patients with streptococcal isolations including Streptococcus pyogenes (Group A streptococcus, GAS, n = 7), Streptococcus agalactiae (Group B streptococcus, GBS, n = 5), Streptococcus pneumoniae (SP, n = 20), alpha-hemolytic (n = 4), beta-hemolytic (n = 2) and gama-hemolytic (n = 2) streptococci. Comparing among GAS, GBS and SP, respiratory isolates were more likely positive for GAS or SP (P = 0.033), whereas cerebrospinal fluid was more likely positive for GBS (P = 0.002). All GAS and GBS, and the majority of SP (90%) were sensitive to penicillin. All SP specimens were sensitive to cefotaxime and vancomycin. These infections were associated with high PICU mortality of 43%, 20% and 25%, respectively. Isolation of streptococci was associated with a 30% mortality and high rates of need for mechanical ventilatory and inotropic supports. Patients with GAS, SP or any streptococcal isolation had relative risks [95% confidence interval (CI), P value] of PICU deaths of 7.5 (CI 3.1-18.1, P < 0.0001), 4.5 (CI 2.0-9.8, P < 0.0002) and 5.7 (CI 3.4-9.5, P < 0.0001), respectively. In SP, older children had significantly higher prevalence of premorbid conditions such as malignancy, mental retardation/cerebral palsy ± seizure disorders, chromosomal or genetic disorders (P = 0.003) than children <5 years of age. Serotypes were available for some of these specimens that included 19A, 6B, 3 and 6C. There were four SP deaths with multiorgan system failure and hemolytic uremic syndrome (two 19A and two serotype 3).

CONCLUSIONS

Severe streptococcal infections are associated with significant morbidity and mortality despite treatment with systemic antibiotics and intensive care unit support. GAS and SP affect the lungs of children, whereas GBS more likely causes meningitis in infants. The expanded coverage of newer polyvalent pneumococcal vaccines can probably prevent infections by serotypes 19A, 19F, 6B and 3.