Introduction: Mycoplasma pneumoniae(M. pneumoniae) causes 10% to 30% of community-acquired pneumonia (CAP). The commonly used first-line antibiotic macrolide (ML) against respiratory tract infection may lead to the increase of ML-resistant M. pneumoniaeinfection. To resolve the problem, a rapid and accurate method for detection of ML-resistant M. pneumoniaeis necessary for treatment adjustment. Aims: The study aims to (1) develop a rapid method for diagnosis of ML-resistance of M. pneumoniaedirectly from clinical specimens; and (2) investigate the prevalence of M. pneumoniaeand ML-resistant M. pneumoniae. Methods: The M. pneumoniaeqPCR results of 689 respiratory tract samples from Queen Mary Hospital collected during April 2010 to May of 2012 were analyzed. Positive nucleic acid from M. pneumoniaeqPCR samples were tested with SimpleProbe real-time PCR coupled to melting curve analysis (SimpleProbe PCR), pyrosequencing and 23S rRNA gene sequencing(23S sequencing) for detection of ML-resistance. Results: A total of 111 samples (16.11%) in 689respiratory tract samples were found M. pneumoniaepositive by qPCR. Of 111, 96 positive nucleic acids were available for this study. Overall, 29 (30.21%, n=96) of ML-resistant M. pneumoniaewere found. 23S sequencing identified 28 mutants (29.17%) and 62 wild–type (64.58%), while 6 (6.25%) of them are failed to be identified. Pyrosequencing identified 28 mutants (29.17%) and 63 wild–type (65.63%), while 5 (5.21%) of them are failed to be identified. The SimpleProbe PCR identified 29 mutants (30.21%) and 65 wild–type (67.71%), while 2 (2.08%) of them are failed to be identified. All ML-resistant M. pneumoniaepositives were found to have A2063G mutation either by 23S sequencing or pyrosequencing. Conclusion: From this study, SimpleProbe PCR is the most sensitive and simple to perform. Therefore, it is highly recommended to be included in the routine testing with positive M. pneumoniaesamples for diagnosis of ML-resistant strain. 23S sequencing or pyrosequencing is recommended to use as a confirmatory test if necessary. / published_or_final_version / Microbiology / Master / Master of Medical Sciences

Background: Rotavirus (RV) is the leading agent of acute gastroenteritis in children under five years old, especially in children of 6~24 months. RV can lead to serious complications or even death. RV can cause a heavy burden of disease particularly in developing countries such as China. To prevent or reduce rotavirus diarrhea (RVD) and RV infection related diseases, damages or complications in children is an important task of public health. RV can also cause extraintestinal damage and complications. The finding of elevated CK-MB has been reported in a couple of Chinese literatures, but the epidemiology and the potential implication of this phenomenon remain poorly understood. Objective: 1. To study the prevalence of elevated serum CK-MB level among children hospitalized with rotavirus gastroenteritis in Guangzhou. 2. To examine factors associated with an elevated CK-MB level 3. To examine the clinical implication of elevated serum CK-MB level with different clinical symptomatology, severity, and disease outcome of rotavirus gastroenteritis in children. Methods: Aretrospective analysis of hospital records had carried out in Guangzhou Women and Children’s Medical Centre (GZWCMC), China. Hospital records during the period from 1 January 2011 to 31 December 2011 of inpatients from GZWCMC were screened and all inpatients with a diagnosis of rotavirus gastroenteritis in GZWCMC were recruited. Result and conclusion: Our study included418 cases of rotavirus infection hospitalized in GZWCMC in Guangdong in 2011, we found elevation of CK-MB a common phenomenon among patients of RV gastroenteritis, and identified a number of risk factors for elevated CK-MB level. These included patients of aged between 6-24 months, cases occurring in autumn or winter, patients coming from low income families, had never been breast-fed, or having dehydration, vomiting, malnutrition, fever, or having an abnormal blood gas and electrolyte. The elevated CK-MB level was positively associated with a higher occurrence of complications, a longer duration of hospitalization, and higher hospital cost per day. / published_or_final_version / Public Health / Master / Master of Public Health

Background: Sexually transmitted diseases (STD) remain a public health concern in worldwide. Human immunodeficiency virus (HIV), one of the STDs, is associated with the increase risk of other STD infections. According to Centers for Disease Control and Prevention (CDC), individuals who are infected with STDs are more likely to be infected with HIV than uninfected individuals. As HIV and other STDs share the same transmission route, the co-infection may be observed more frequently in the population. To control the number of co-infection, screening programs are essential in all areas. While screening for individual infections are necessary, the prevalence of co-infection should also be evaluated for surveillance programs. The prevalence of individual STDs have been studied in various reviews, but the population prevalence of the co-infection was not widely studied. Therefore, a systematic review is conducted to provide a summary of the prevalence of HIV with syphilis, chlamydia, gonorrhea and herpes simplex virus (HSV-2) and co-infection in various populations. Methods: PubMed database is chosen for selection of potential publications in this systematic review. Various keywords are used for the search and and only English publications are selected for review. Studies with statistical data on individual infection but not the co-infection were excluded. Results: Ten studies from various populations are selected for this review. Nine studies were conducted in healthcare facilities and one was conducted in a working site. The number of study participants ranged from 336 to 1661 with a mean age of 32 years old. The average of prevalence of HIV and the chosen STDs was around 20%—highest prevalence is observed in HSV-2 with HIV co-infection. Conclusion: The prevalence of co-infection is low but it cannot be neglected. Simultaneous screening for HIV and other STDs is not necessary in all areas, but it will be very useful in certain facilities where high-risk populations, for example sex workers, MSM etc are served. Such low prevalence of STD co-infection should be maintained and it is the responsibility of both the individuals and the society. / published_or_final_version / Public Health / Master / Master of Public Health

Introduction: Mycoplasma pneumoniae (M. pneumoniae) has been a major cause of community-acquired pneumonia (CAP), accounting for about 10-30% of the cases. Previously, a local study revealed that more than 60% of clinical isolates of M. pneumoniae exerted A2063G mutation, which confers a high level of macrolide drug resistance and results in treatment failure. While A2063G is the only mutation identified locally, a rapid diagnostic assay for detection of this single point mutation is urgently needed for switching the drug of choice. Aims: This study aims to develop a rapid PCR assay for detection of A2063G mutation of M. pneumoniae isolates for our locality, to compare with other commercially available assays and to further confirm the prevalence of A2063G mutation in macrolide-resistance M. pneumoniae (MRMP) in Hong Kong. Methods: A total of 110 respiratory tract samples were collected from 102 patients in Hong Kong Sanatorium and Hospital during April 2013 to April 2014. They were analyzed by an in-house hybridization-probe real-time PCR assay coupled with melting curve analysis to detect the presence of M. pneumoniae and the target A2063G point mutation. Results were compared with a commercial real-time PCR assay and the A2063G point mutation was further confirmed by 23S rRNA gene sequencing. The limit of detection (LOD), mutation threshold determination and cross reactivity of the in-house assay were also evaluated. Results: Over 40% (47/110) of the respiratory tract samples were tested positive for M. pneumoniae by the in-house assay and 36.2% (17/47) of the positive samples exerted A2063G mutation. The limit of detection was 500 copies/ml as evaluated using external quality control samples. Twenty well-characterized clinical isolates of M. pneumoniae were used to evaluate the A2063G mutation threshold. The mutation threshold for A2063G mutant detection was above 60%. This assay did not show any cross-reactivity with common clinical isolates from the respiratory tract samples. Conclusion: In this study, an in-house real-time PCR assay was evaluated and demonstrated its great potential as a rapid clinical diagnostic tool. The assay was highly sensitive and specific in detecting M. pneumoniae and its A2063G mutation from clinical samples in Hong Kong. The results were almost concordant to the current routine testing, with the advantage of lower cost and shorter turnaround time for rapid detection. / published_or_final_version / Microbiology / Master / Master of Medical Sciences

Infections frequently occur on both networks of devices and networks of people, and can model not only viruses, but also information, rumors, and product use. However, in many circumstances, the infection process itself is hidden, and only the effects, e.g. sickness or knowledge, can be observed. In addition, this information is likely incomplete, missing many sick nodes, as well as inaccurate, with false positives. To use this data effectively, it is often essential to identify the infection process causing the sickness, or even whether the cause is an infection. For our purposes, we consider the susceptible-infected (SI) infection model. We seek to distinguish between infections and random sickness, as well as between different infection (or infection-like) processes in a limited information setting. We formulate this as a hypothesis testing problem, where (typically) in the null, the sickness affects nodes at random, and in the alternative, the infection is spread through the network. Similarly, we consider the case where the sickness may be caused by one of two infection (or infection-like) processes, and we wish to find which is the causative process. We do this is a setting with very limited information, given only a single snapshot of the infection. Only a small portion of the infected population reports the sickness. In addition, there are several other limitations we consider. There may be false positives, obfuscating the infection. Similarly, there may be a random sickness and epidemic process occurring simultaneously. Knowledge of the graph topology may be incomplete, with unknown edges over which the infection may spread. The graph may also be weighted, affecting the way the infection spreads over the graph. In all these cases, we develop algorithms to identify the causative process of the infection utilizing the fact that infected nodes will be clustered. We demonstrate that under reasonable conditions, these algorithms detect an infection with asymptotically zero error probability as the graph size increases. / text

Not available / text

published_or_final_version / abstract / toc / Surgery / Master / Master of Surgery

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

No description available.

Acquired immunodeficiency syndrome (AIDS) remains an epidemic illness with no known cure. Survival time after infection with the human immunodeficiency virus (HIV), has been lengthened considerably. Rates of new infection among the at-risk male homosexual populations have decreased. Prevention is possible through effective, targeted interventions. This study is an exploration of the role or health locus of control, an individual difference construct from the area of social learning theory, in the maintenance of health-oriented behaviours, co-risk indicative behaviours, and high-risk behaviours in a population of adult male homosexuals attending a general medical clinic. The findings result in distinctly different past histories and present patterns of homosexual behaviours among the two serostatus subpopulations. Low internal expectancy of control over health repeatedly relates in distinctive patterns with the areas of level of happiness, condom usage, and hish-risk sexual behaviours. High internal expectancy of control relates significantly to knowledge-related variables. The physician plays a pivotal role as the source of useful information in this at-risk population. The study population as a whole reports accurate knowledge about HIV and AIDS. The men have reduced high-risk behaviours, increased safer sexual behaviours, and implemented the changes advocated. Serostatus differentiates for many high-risk behavioural patterns. There remains a small core of men among the study participants who continue to participate in high-risk sexual behaviours.