Pneumonia is a common infectious disease ofthe lungs. Community acquired pneumonia (CAP) refers to pneumonia occurred outsideof the hospitals or long term care facility. People with weakened immunesystems, children and people aged 65+ and resistant to antibiotics are particularitylikely to be affected with pneumonia, ranging from mild to severe, possible lifethreatening. The most common typical bacterial etiology associated with CAP includeStreptococcus pneumonia, Haemophilus influenza, and Moraxella catarrhalisetc.
Atypical pathogens include Mycoplasma pneumoniae, Chlamydophilapneumoniae, Rhinovirus, Legionnaires disease etc. Common symptoms of pneumonia include coughing,fatigue, nausea, vomiting, shortness of breath, pleuritic chest pain whenbreathing/coughing and fever etc. The main and standard diagnostic tools of CAPis based on microbiology presentations, serology, sputum culture, urine and culturessuch as blood agar of respiratory tract specimens.
Lower respiratory specimens,collected directly from the site of an infection, e.g., blood, can providesgood evidence of microorganisms causing the infection/disease. The choice ofsample type is important in obtaining an efficient laboratory diagnosis. The sampletypes 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 viralpathogens such as M. pneumonia. Each of these sample types aim toidentify the causative pathogens causing infections and any abnormalities ofthe lungs.
For children between the age of 2 and 10,nose/throat swabs were performed to detect the presence of a virus, parainfluenzapneumonia. Antigen tests can also be used to detect the antigens fightingthe virus. Sputum cultures are not so common in children and the accuracy ofthese tests is uncertain, because children are often unable to cough up enoughphlegm/sputum from the lower airways, specimens are also usually contaminatedwith oral flora enabling bacterial pathogens such as mycobacterium almost hardto be identified on a microscope. However, obtaining a susceptible sputumculture samples from an adults allows for further identification of viralpathogens using PCR. For example, for thediagnosis of Pneumocystis pneumonia, sputum cultures can be used byinhaling a hypertonic saline solution. In some cases, bronchoscopy can be usedto collect sputum/tissue samples for detection of pathogens trapped in theairways or any blockages in the airways or lungs. Haemophilus influenzacan be detected using bronchoscopy. For age groups between 10-18 yrs, urine and Enzyme-linkedimmunoassay (ELIZA) were performed to detect the microorganisms causing Metapneumovirus(hMPV) and Legionnaires’ disease (LD).
The gram negative bacterium; Legionellapneumophila causing Legionnaires’ disease is detected by urine samples, whichis a valuable tool for rapid laboratory diagnosis, as well as sputum by taking specimen samplefrom the lower respiratory on to culture media. This allows for all legionellaspecies to be identified. An acute Pontiac fever flu-like respiratory illness,nonfatal is also caused by the bacterium, contacted by upper respiratoryinfection 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, thechoice of sample type chose to detect pathogens such as Chlamydophilapneumonia, Pneumocystis jirovecii and Pseudomonas aeruginosa; weredetected using blood cultures as well as sputum. The advantage of using bloodcultures to detect these microorganisms is blood contains the bacterialpathogens that’s infecting the lungs or the airways, spreading and circulatingin the body. Therefore susceptible tests can be obtained from blood cultures. Forpeople between the age of 19 and 35, several sample tests were performed; radiographyand tomography.
Haemophilus influenza and Mycobacterium tuberculosiswere detected using tomography to find some kind of inflammation orabnormalities in the lungs. However,this sample type can only be used to identify abnormalities to suggest M tuberculosisbut further tests can be done to confirm diagnosis such as sputum smear. Acid-fast-bacillistain; a microscopic examination can be used to identify the bacterium causing Mtuberculosis. Chlamydophila pneumonia, Pneumocystis jirovecii are absorbedto be increasing in individuals with HIV positive according to.
Another crucial and common form of laboratorydiagnosis; serology sample type that can be performed to identify the causativemicroorganisms.For age groups between 36-65 yrs, urinesamples, chest radiogram, bronchoscopy, BAL and tomography sample types wereused. S. pneumonia is presumed to be the most common form of bacterial CAPinfection/disease. The most reliable laboratory diagnosis of S.
pneumoniais culture based methods sampling which providing definite diagnosis andfurther diagnosis leads to the detection of Pneumococcal Septic arthritis,using microscopic analysis to confirm of diagnosis. In general, according toBarth, L., Melvin, p., et el 2008, adults are more prone to be exposed to S.
pneumonia than children. Sputumexaminations in children for this particular infection can challenging sinceyoung children might not cough up enough sputum. Therefore, Cerebrospinal fluidanalysis (CSF) might be carried out in gram stain smears in order to diagnose anddetect other conditions associated with CAP. New pathogenic diagnostics techniques for the upper/lowerrespiratory are potentially developing; nuclei acid detection assays (NAT) and breathetests. Although this test have limitations and is yet to be confirmed for pneumonialinfection/disease, they will potentially establish rapid laboratory diagnosis, accurateand reliable results and easily repeatable in the context of identifying respiratorypathogens.
