Pneumonia is a common infectious disease of
the lungs. Community acquired pneumonia (CAP) refers to pneumonia occurred outside
of the hospitals or long term care facility. People with weakened immune
systems, children and people aged 65+ and resistant to antibiotics are particularity
likely to be affected with pneumonia, ranging from mild to severe, possible life
threatening. The most common typical bacterial etiology associated with CAP include
Streptococcus pneumonia, Haemophilus influenza, and Moraxella catarrhalis
etc. Atypical pathogens include Mycoplasma pneumoniae, Chlamydophila
pneumoniae, Rhinovirus, Legionnaires disease etc.  Common symptoms of pneumonia include coughing,
fatigue, nausea, vomiting, shortness of breath, pleuritic chest pain when
breathing/coughing and fever etc.

The main and standard diagnostic tools of CAP
is based on microbiology presentations, serology, sputum culture, urine and cultures
such as blood agar of respiratory tract specimens. Lower respiratory specimens,
collected directly from the site of an infection, e.g., blood, can provides
good evidence of microorganisms causing the infection/disease. The choice of
sample type is important in obtaining an efficient laboratory diagnosis. The sample
types taken include blood cultures, sputum, urine tests, nose/throat swab,
physical examinations: radiograph, Broncho alveolar lavage (BAL), bronchoscopy,
and tomography. Other sample types include serology and PCR to detect atypical viral
pathogens such as M. pneumonia. Each of these sample types aim to
identify the causative pathogens causing infections and any abnormalities of
the lungs.

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For children between the age of 2 and 10,
nose/throat swabs were performed to detect the presence of a virus, parainfluenza
pneumonia. Antigen tests can also be used to detect the antigens fighting
the virus. Sputum cultures are not so common in children and the accuracy of
these tests is uncertain, because children are often unable to cough up enough
phlegm/sputum from the lower airways, specimens are also usually contaminated
with oral flora enabling bacterial pathogens such as mycobacterium almost hard
to be identified on a microscope. However, obtaining a susceptible sputum
culture samples from an adults allows for further identification of viral
pathogens using PCR.  For example, for the
diagnosis of Pneumocystis pneumonia, sputum cultures can be used by
inhaling a hypertonic saline solution. In some cases, bronchoscopy can be used
to collect sputum/tissue samples for detection of pathogens trapped in the
airways or any blockages in the airways or lungs. Haemophilus influenza
can be detected using bronchoscopy.

For age groups between 10-18 yrs, urine and Enzyme-linked
immunoassay (ELIZA) were performed to detect the microorganisms causing Metapneumovirus
(hMPV) and Legionnaires’ disease (LD). The gram negative bacterium; Legionella
pneumophila causing Legionnaires’ disease is detected by urine samples, which
is a valuable tool for rapid laboratory diagnosis,  as well as sputum by taking specimen sample
from the lower respiratory on to culture media. This allows for all legionella
species to be identified. An acute Pontiac fever flu-like respiratory illness,
nonfatal is also caused by the bacterium, contacted by upper respiratory
infection that imitates the flu. Risks factors associated with LD include smoking,
individuals with weakened immune systems and diabetes.

For an individual who is HIV positive, the
choice of sample type chose to detect pathogens such as Chlamydophila
pneumonia, Pneumocystis jirovecii and Pseudomonas aeruginosa; were
detected using blood cultures as well as sputum. The advantage of using blood
cultures to detect these microorganisms is blood contains the bacterial
pathogens that’s infecting the lungs or the airways, spreading and circulating
in the body. Therefore susceptible tests can be obtained from blood cultures. For
people between the age of 19 and 35, several sample tests were performed; radiography
and tomography. Haemophilus influenza and Mycobacterium tuberculosis
were detected using tomography to find some kind of inflammation or
abnormalities in the lungs.  However,
this sample type can only be used to identify abnormalities to suggest M tuberculosis
but further tests can be done to confirm diagnosis such as sputum smear. Acid-fast-bacilli
stain; a microscopic examination can be used to identify the bacterium causing M
tuberculosis.

Chlamydophila pneumonia, Pneumocystis jirovecii are absorbed
to be increasing in individuals with HIV positive according to. Another crucial and common form of laboratory
diagnosis; serology sample type that can be performed to identify the causative
microorganisms.

For age groups between 36-65 yrs, urine
samples, chest radiogram, bronchoscopy, BAL and tomography sample types were
used. S. pneumonia is presumed to be the most common form of bacterial CAP
infection/disease. The most reliable laboratory diagnosis of S. pneumonia
is culture based methods sampling which providing definite diagnosis and
further diagnosis leads to the detection of Pneumococcal Septic arthritis,
using microscopic analysis to confirm of diagnosis. In general, according to
Barth, L., Melvin, p., et el 2008,   adults are more prone to be exposed to S. pneumonia than children. Sputum
examinations in children for this particular infection can challenging since
young children might not cough up enough sputum. Therefore, Cerebrospinal fluid
analysis (CSF) might be carried out in gram stain smears in order to diagnose and
detect other conditions associated with CAP.

New pathogenic diagnostics techniques for the upper/lower
respiratory are potentially developing; nuclei acid detection assays (NAT) and breathe
tests. Although this test have limitations and is yet to be confirmed for pneumonial
infection/disease, they will potentially establish rapid laboratory diagnosis, accurate
and reliable results and easily repeatable in the context of identifying respiratory
pathogens.