Community-acquired pneumonia (CAP) is a major cause of adult mortality in Asia. Appropriate empirical treatment depends on knowledge of the pathogens commonly responsible. However, assessing the aetiological significance of identified organisms is often difficult, particularly with sputum isolates that might represent contamination with oropharyngeal flora.
Sir, I read with interest the elegantly written CME article by Liam C K recently!. The choice of empiric antibiotic(s) in treating hospitalized adult patients with communityacquired pneumonia (CAP) is important as it can influence clinical outcomes 2. As correctly pointed out by the author, patients with CAP requiring hospitalization should, in addition to a ~-lactam stable antibiotic, be covered with a macrolide, to combat atypical pathogens such as Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydia pneumoniae. Such is the recommendation from most foreign guidelines 3. 4. Here I wish to add our own observation based on a prospective study conducted between 2002 and 2004 of 141 adult patients with CAP hospitalized in Seremban Hospital in which we studied the clinical outcomes of patients treated empirically with and without a macrolide added to their ~-lactam stable antibiotic, recently published in Respirology 5.
Mycoplasma pneumoniae is increasingly recognized as an important cause of community acquired pneumonia (CAP) in children. We determined the importance of M. pneumoniae as a causative agent in 170 children aged 1 month to 15 years who were hospitalized with CAP over a 6-month period. The diagnosis of M. pneumoniae infection was based on serological evidence obtained by a particle agglutination test (SERODIA-MYCO II). A positive serological diagnosis was made if the acute phase serum titer was more than 1:160 or paired samples taken 2-4 weeks apart showed a four-fold or greater rise in the serum titer. M. pneumoniae was identified as the causative agent in 40 (23.5%) children. Children with M. pneumoniae infection were more likely to be older than 3 years (OR 4.0 95%CI 1.8-9.1, p<0.001), Chinese (OR 4.3 95%CI 2.0-8.9, p<0.001), have a duration of illness longer than 7 days prior to admission (OR 6.0 95%CI 2.7-13.5, p<0.001) and have perihilar interstitial changes on chest X-ray (OR 4.6 95%CI 2.2-9.9, p<0.001). A significant number of hospital admissions for CAP in Malaysian children can be attributed to M. pneumoniae. It is important to identify these children so as to administer the most appropriate antibiotic treatment.
Hyperimmunoglobulin E syndrome (HIE) is a rare condition characterised by marked elevation of serum IgE level, chronic dermatitis, intense pruritus, and recurrent serious infection. The major organism is usually S aureus. We report a case of an infant with HIE, who had pulmonary nocardiosis. The clinical features, immunological abnormalities, and radiological features of the condition are described. The child finally succumbed to the complications of pulmonary nocardiosis.
Rituximab is a B-cell-depleting monoclonal anti-CD20 antibody. It is widely used in haematology and rheumatology. However, usage of rituximab in immunosupressed patient has been associated with various opportunistic infections. The authors reported a case of refractory rheumatoid arthritis treated with rituximab, which later presented with non-resolving pneumonia with pulmonary nodule. Percutaneous computer tomogram guided lung biopsy was arranged to confirm the suspicion of tuberculosis, but did not yield conclusive results. Later, she presented left-chest abscess and underwent incision and drainage. The pus culture and sensitivity confirmed pulmonary nocardiosis with chest wall dissemination. She was treated with 2-week course of trimethoprim sulfamethoxazole and responded. The authors also reviewed published cases of nocardiosis post-rituximab.
Multi-resistant Enterobacteriaceae pose a serious threat of hospital acquired infections and their rapid identification is important for better clinical outcome. This study describes the rapid identification of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae of the sulphydryl variable-type by fluorescent in-situ hybridization. The method which rapidly identifies the target genes within 1 h could be a potentially rapid bacterial diagnostic tool.
The aetiology of community acquired pneumonia varies according to the region in which it is acquired. This review discusses those causes of CAP that occur in the tropics and might not be readily recognizable when transplanted to other sites. Various forms of pneumonia including the viral causes such as influenza (seasonal and avian varieties), the coronaviruses and the Hantavirus as well as bacterial causes, specifically the pneumonic form of Yersinia pestis and melioidosis are discussed.
Introduction.Burkholderia pseudomallei (melioidosis) is an important cause of community-acquired pneumonia (CAP) in the tropics. Selective medium is recommended for laboratory diagnosis with non-sterile respiratory samples, while PCR is not routinely used due to variable reported performance. The effectiveness of these diagnostic modalities varies by site.Aim. To compare selective media and real-time PCR (qPCR) with routine media in detecting B. pseudomallei in CAP respiratory samples in a low-incidence setting in Kuala Lumpur, Malaysia.Methodology. Respiratory samples were routinely cultured on blood, chocolate and MacConkey agar (RESP-ROUTINE), and compared to culture on selective Ashdown medium (RESP-SELECTIVE) and qPCR. The gold standard was routine culture of B. pseudomallei from any site (ALL-ROUTINE).Results.B. pseudomallei was detected in 8/204 (3.9 %) samples. Overall sensitivity rates differed (P=0.03) for qPCR (100%), RESP-SELECTIVE (87.5%) and RESP-ROUTINE (50%). There was a trend towards lower median days to positive culture for RESP-SELECTIVE (1 day) compared to RESP-ROUTINE (2 days, P=0.08) and ALL-ROUTINE (2 days, P=0.06). Reagent costs for each additional detection were USD59 for RESP-SELECTIVE and USD354 for PCR.Conclusions. In a low-incidence setting, selective culture of respiratory samples on Ashdown was more sensitive and allowed quicker identification than routine media, at reasonable cost. Blood cultures are critical, confirming four cases missed by routine respiratory culture. Selective medium is useful in early pneumonia (pre-sepsis) and resource-limited settings where blood cultures are infrequently done. Real-time PCR is costly, but highly sensitive and useful for high-risk patients with diabetes, cancer or immunosuppressants, or requiring ventilation or intensive care.
Community-acquired pneumonia (CAP) is still a major cause of morbidity and mortality especially to children and compromised hosts, such as the old and those with underlying chronic diseases. Knowledge of pathogens causing CAP constitutes the basis for selection of antimicrobial treatment. Previous data have shown that etiological agents can be identified in only up to 50% of patients, but this figure can be improved by using polymerase chain reaction (PCR). This study was designed to evaluate multiplex real-time PCR as a method for rapid differential detection of five bacterial causes of CAP (Streptococcus pneumoniae, Burkholderia pseudomallei and atypical bacterial pathogens namely Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila) in CAP patients attending Hospital Tengku Ampuan Afzan (HTAA)/ Kuantan, Pahang, Malaysia. Two previously developed multiplex real-time PCR assays, duplex for the differential detection of S. pneumoniae and B. pseudomallei and triplex for the atypical bacterial pathogens, were used to detect a bacterial cause of CAP in blood and respiratory samples. Thus, 46 blood and 45 respiratory samples collected from 46 adult CAP patients admitted to HTAA were analysed by multiplex real-time PCR assays and conventional methods. The microbial etiology of CAP could be established for 39.1% (18/46) of CAP patients by conventional methods and this was increased to 65.2% (30/46) with the additional use of real-time PCR. The most frequently detected pathogens were S. pneumoniae (21.7% - all by PCR alone), Klebsiella pneumoniae (17.3%), B. pseudomallei (13% - 83% of them positive by PCR alone and 17% by both culture and PCR), Pseudomonas aeruginosa (6.5%), M. pneumoniae (6.5% - all by serology), C. pneumoniae (4.3% - all positive by both PCR and serology), L. pneumophila (2.1% - all by PCR alone), Escherichia coli (4.3%). Haemophilus infuenzae, Acinetobacter lwoffii and Acinetobacter baumannii were detected by conventional methods (2.1% for each).
The aims of this study were to investigate the frequency of Mycobacterium tuberculosis as a cause of community-acquired pneumonia (CAP) requiring hospitalization in Malaysia, and to define the clinical features of pulmonary tuberculosis (PTB) that distinguish it from non-TB CAP.
In many parts of Asia, the inaccessibility and high cost of diagnostic tests have hampered the study of community-acquired pneumonia (CAP) caused by atypical respiratory pathogens.
Establishing a microbial diagnosis for patients with community-acquired pneumonia (CAP) is still challenging and is often achieved in only 30-50% of cases. Polymerase chain reaction (PCR) has been shown to be more sensitive than conventional microbiological methods and it could help to increase the microbial yield for CAP patients. This study was designed to develop, optimize and evaluate multiplex real-time PCR as a method for rapid differential detection of five bacterial causes of CAP namely Streptococcus pneumoniae, Burkholderia pseudomallei and atypical bacterial pathogens, Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila. Duplex and triplex real-time PCR assays were developed using five sets of primers and probes that were designed based on an appropriate specific gene for each of the above CAP pathogens. The performance of primers for each organism was tested using SYBR Green melt curve analysis following monoplex realtime PCR amplification. Monoplex real-time PCR assays were also used to optimize each primers-probe set before combining them in multiplex assays. Two multiplex real-time PCR assays were then optimized; duplex assay for the differential detection of S. pneumoniae and B. pseudomallei, and triplex assay for the atypical bacterial pathogens. Both duplex and triplex real-time PCR assays were tested for specificity by using DNA extracted from 26 related microorganisms and sensitivity by running serial dilutions of positive control DNAs. The developed multiplex real-time PCR assays shall be used later for directly identifying CAP causative agents in clinical samples.