A study to assess the magnitude of atypical pneumonia by serum polymerase chain reaction in children aged 3 years to 18 years at Kempegowda Institute of Medical Sciences hospital, Bengaluru, Karnataka, India

Ramya H. S., Anjana Gopi, Vivetha Elango, Mansi Kumar


Background: Atypical organisms are a common causative agent of pneumonia in children more than 3 years of age, causing around 10-30% of the cases. Though atypical pathogens are said to cause relatively milder form of pneumonia as compared to other bacterial and viral pathogens, severe manifestations can also occur. Early identification of these pathogens can help in starting treatment with macrolides, which can reduce the length of hospital stay and mortality. Hence in this study the prevalence of atypical organisms was identified by using serum Polymerase chain reaction (PCR).

Methods: This was a prospective observational study conducted in children between 3 years to 18 years of age with clinical diagnosis of pneumonia admitted in wards and PICU in KIMS hospital. Authors excluded Immunocompromised children. Detailed history and clinical examination was done. Investigations - complete hemogram, Chest Xray, blood Culture and sensitivity and serum PCR was done for a sample size of 100 children.

Results: In this study among the three atypical organisms, Legionella pneumoniae was identified in 2% of the cases by serum PCR.

Conclusions: In this study among the three atypical pathogens authors could only identify Legionella pneumoniae. Prevalence of Legionella pneumoniae was 2%. While treating children aged 3 years to 18 years with pneumonia, a high degree of suspicion of atypical pathogens is required, especially in Legionella because of its high mortality rate. In such circumstances adding macrolides along with other antibiotics will be beneficial to the patients outcome and duration of hospital stay.


Atypical pneumonia, Legionella, PCR

Full Text:



Mathai E, Padmavathy K, Cherian T, Inbamalar U, Varkki S. Mycoplasma pneumoniae antibodies in children with acute respiratory infection. Ind Pediatr. 2001;38(2):157-60.

Cunha BA. Atypical pneumonias. In: Conn RB, Borer WZ, Snyder JW, eds. Current Diagnosis 9th ed. Philadelphia: WB Saunders; 1996: 99:123-132.

Agarwal J, Awasthi S, Rajput A, Tiwari M, Jain A. Atypical bacterial pathogens in community-acquired pneumonia in children: a hospital-based study. Trop Doctor. 2009 Apr;39(2):109-11.

Singh M. Atypical Pneumonia in Children Manju Salaria. Ind Pediatr. 2002;39:259-66.

Rodrigues CM, Groves H. Community-acquired pneumonia in children: the challenges of microbiological diagnosis. J Clini Microbiol. 2018 Mar 1;56(3):e01318-17.

Alexiou‐Daniel S, Stylianakis A, Papoutsi A, Zorbas I, Papa A, Lambropoulos AF, et al. Application of polymerase chain reaction for detection of Legionella pneumophila in serum samples. Clini Microbiol Infect. 1998 Mar;4(3):144-8.

Daxboeck F, Khanakah G, Bauer C, Stadler M, Hofmann H, Stanek G. Detection of Mycoplasma pneumoniae in serum specimens from patients with mycoplasma pneumonia by PCR. Int J Medi Microbiol. 2005 Aug 22;295(4):279-85.

Witte L, Droemann D, Dalhoff K, Rupp J. Chlamydia pneumoniae is frequently detected in the blood after acute lung infection. Eur Resp J. 2011 Mar 1;37(3):712-4.

Fast Track diagnostics. FTD Respiratory pathogens 33. Available at: Accessed 12 November 2019.

Neil K, Berkelman R. Increasing incidence of legionellosis in the United States, 1990–2005: changing epidemiologic trends. Clini Infect Dis. 2008 Sep 1;47(5):591-9.

Saraya T. Mycoplasma pneumoniae infection: Basics. J Gen Family Medi. 2017 Jun;18(3):118-25.

Ng V, Tang P, Jamieson F, Guyard C, Low DE, Fisman DN. Laboratory-based evaluation of legionellosis epidemiology in Ontario, Canada, 1978 to 2006. BMC Infect Dis. 2009 Dec;9(1):68.

Hicks LA, Rose CE, Fields BS, Drees ML, Engel JP, Jenkins PR, et al. Increased rainfall is associated with increased risk for legionellosis. Epidemiol Infect. 2007 May;135(5):811-7.

Beer S, Boldur I, Kazak R, Avidan S, Kannai Y. Serum antibodies to Legionella agents in bronchial asthma. Arch Dis Child. 1985 Mar 1;60(3):225-30.

Esposito S, Principi N. Asthma in children. Paediatr Drugs. 2001 Mar 1;3(3):159-68.

Brown RB, Sands MI, Ficalora RO, Jaciow DM. Concurrent community-acquired pneumonia with Legionella pneumophila and Streptococcus pneumoniae. South Medi J. 1987 Mar;80(3):401-2.

Lindsay DS, Abraham WH, Findlay W, Christie P, Johnston F, Edwards GF. Laboratory diagnosis of legionnaires’ disease due to Legionella pneumophila serogroup 1: comparison of phenotypic and genotypic methods. J Medi Microbiol. 2004 Mar 1;53(3):183-7.

Helbig JH, Engelstädter T, Maiwald M, Uldum S, Witzleb W, Lück PC. Diagnostic relevance of the detection of Legionella DNA in urine samples by the polymerase chain reaction. Eur J Clini Microbiol Infect Dis. 1999 Nov 1;18(10):716-22.

Alexander NT, Fields BS, Hicks LA. Epidemiology of reported pediatric Legionnaires' disease in the United States, 1980-2004. In 48th Interscience Conference on Antimicrobial Agents and Chemotherapy 2008.