The reliability of a rapid molecular detection method in determining the prevalence of rifampicin-resistant Mycobacterium tuberculosis in an urban district health facility in Malaysia

@#Introduction: Rifampicin is a key first-line antimycobacterial agent employed for the treatment of pulmonary tuberculosis (PTB). This study sought to obtain prevalence data on rifampicin-resistant Mycobacterium tuberculosis among smear-positive PTB patients in the Klang District of Malaysia. Materials and Methods: A total of 103 patients from the Chest Clinic of Hospital Tengku Ampuan Rahimah with sputum smears positive for acid-fast bacilli were included in this cross-sectional study. All sputa were tested using Xpert MTB/RIF to confirm the presence of M. tuberculosis complex and detect rifampicin resistance. Sputa were also sent to a respiratory medicine institute for mycobacterial culture. Positive cultures were then submitted to a reference laboratory, where isolates identified as M. tuberculosis complex underwent drug susceptibility testing (DST). Results: A total of 58 (56.3%) patients were newly diagnosed and 45 (43.7%) patients were previously treated. Xpert MTB/RIF was able to detect rifampicin resistance with a sensitivity and specificity of 87.5% and 98.9%, respectively. Assuming that a single resistant result from Xpert MTB/RIF or any DST method was sufficient to denote resistance, a total of 8/103 patients had rifampicinresistant M. tuberculosis. All eight patients were previously treated for PTB (p<0.05). The overall prevalence of rifampicin resistance among smear-positive PTB patients was 7.8%, although it was 17.8% among the previously treated ones. Conclusion: The local prevalence of rifampicin-resistant M. tuberculosis was particularly high among previously treated patients. Xpert MTB/RIF can be employed in urban district health facilities not only to diagnose PTB in smear-positive patients, but also to detect rifampicin resistance with good sensitivity and specificity.

Trichosporon asahii fungaemia in an immunocompetent polytrauma patient who received multiple antibiotics

@#Trichosporon asahii is a yeast-like fungus that is emerging as an important cause of invasive infections in tertiary medical centres. A 58-year-old Chinese man with no known medical illnesses presented with liver lacerations and multiple fractures following an alleged 12-foot fall at a construction site. The gravity of his injuries and poor haemodynamic status necessitated an intensive care unit (ICU) admission, during which several febrile episodes were detected and multiple antibiotics were administered. After being in the ICU for at least two weeks, a urease-positive yeast was isolated from the patient’s blood. The yeast formed dry, fuzzy and wrinkled white colonies on Sabouraud dextrose agar following prolonged incubation, and produced blastoconidia, true hyphae, pseudohyphae and arthroconidia on slide culture. It was identified biochemically by the ID 32 C kit as T. asahii. The yeast had elevated minimal inhibitory concentration (MIC) values to fluconazole, amphotericin B, flucytosine and all echinocandins tested. In view of this, the patient was treated with voriconazole and was successfully transferred to the general medical ward.

The crucial role of molecular testing to facilitate the diagnosis of pneumocystis pneumonia during pregnancy

Pneumocystis pneumonia is an important human immunodeficiency virus (HIV)-associated opportunistic infection, and especially so in pregnant HIV-positive patients. We report a case of a 40-year-old woman in her first trimester of pregnancy who initially presented with acute gastroenteritis symptoms but due to a history of high-risk behaviour and the observation of oral thrush, she was worked up for HIV infection. Her retroviral status was positive and her CD4+ T cell count was only 8 cells/mL. She was also worked up for pneumocystis pneumonia due to the presence of mild resting tachypnoea and a notable drop in oxygen saturation (from 100% to 88%) following brief ambulation. Her chest radiograph revealed bilaterally symmetrical lower zone reticular opacities and Giemsa staining of her bronchoalveolar lavage (BAL) was negative for Pneumocystis jirovecii cysts. However, real-time P. jirovecii polymerase chain reaction (PCR) testing on the same BAL specimen revealed the presence of the organism. A course of oral co-trimoxazole plus prednisolone was commenced and her clinical condition improved.

Conventional versus molecular detection of Chlamydia trachomatis and Neisseria gonorrhoeae among males in a sexually transmitted infections clinic

Chlamydia trachomatis and Neisseria gonorrhoeae are important bacterial pathogens of sexually transmitted infections (STIs) worldwide. This study sought to compare the analytical sensitivity and specificity of conventional methods against a rapid molecular method in detecting STIs caused by these bacteria. Methods: Ninety five first-time male attendees of the Genito-urinary Medicine Clinic in Hospital Kuala Lumpur were included in this cross-sectional study. The detection of C. trachomatis was achieved through direct fluorescence antibody (DFA) staining of urethral swabs and real-time polymerase chain reaction testing (Xpert® CT/NG assay) on urine specimens. N. gonorrhoeae was detected through Gram staining and culture of urethral swabs and Xpert® CT/ NG assay on urine specimens. Results: From the Xpert® CT/NG results, 11 (11.6%) attendees had chlamydia, 23 (24.2%) had gonorrhoea and 8 (8.4%) had both STIs. The sensitivity and specificity of DFA in detecting chlamydia compared to Xpert® CT/NG were 5.3% (95% CI: 0-28) and 94.7% (95% CI: 86-98), respectively. For gonorrhoea, the sensitivity and specificity of Gram staining were 90.3% (95% CI: 73-98) and 95.3% (86-99), respectively, whereas the sensitivity and specificity of culture compared to Xpert® CT/NG were 32.2% (95% CI: 17-51) and 100% (95% CI: 93-100), respectively. Conclusion: Although Gram-stained urethral swab smears are sensitive enough to be retained as a screening tool for gonorrhoea, culture as well as DFA lack sensitivity and are poorly suited to screen for gonorrhoea and chlamydia, respectively. However, owing to their high specificity, conventional detection methods are still suitable as confirmatory tests for gonorrhoea and chlamydia.

Seroprevalence of acute dengue in a Malaysian tertiary medical centre

Objectives: The aims of this study were to determine the seroprevalence of acute dengue in Universiti Kebangsaan Malaysia [UKM] Medical Centre and its correlation with selected haematological and biochemical parameters

Methods: This cross-sectional study was conducted from January to June 2015. A patient was serologically diagnosed with acute dengue if the dengue virus IgG, IgM or NS-1 antigen was reactive

Results: Out of 1,774 patients suspected to have acute dengue, 1,153 were serologically diagnosed with the infection, resulting in a seroprevalence of 64.9%. Dengue-positive patients had a lower mean platelet count [89 x 10[9]/L] compared to the dengue-negative patients [171 x 10[9]/L] [p<0.0001]. The mean total white cell count was also lower in the dengue-positive cases [4.7 x 10[9]/L vs. 7.2 x 10[9]/L; p<0.0001]. The mean haematocrit was higher in patients with acute dengue [42.5% vs. 40.0%; p<0.0001]. Likewise, the serum alanine transaminase level was also higher in patients with acute dengue [108 U/L vs. 54 U/L; p<0.0001]

Conclusions: Dengue is very prevalent in UKM Medical Centre as most patients suspected to have acute dengue had serological evidence of the infection. The platelet count was the single most likely parameter to be abnormal [i.e. low] in patients with acute dengue

Screening for New Delhi metallo-Beta-lactamase-1 in Enterobacteriaceae: is there a role for the modified Hodge test?

Objective: The New Delhi metallo-Beta-lactamase-1 [NDM-1] enzyme is a plasmid-encoded enzyme that inactivates carbapenem antibiotics. This study aims to ascertain if the modified Hodge test [MHT] has a role in screening for NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility

Methods: Over a period of one year, all Enterobacteriaceae isolates from all clinical specimens with reduced susceptibility to at least one carbapenem were subjected to MHT and conventional polymerase chain reaction [PCR] detection of the NDM-1 gene

Results: A total of 13,098 Enterobacteriaceae isolates were screened and 63 [0.48%] had reduced susceptibility to at least one carbapenem. Out of the 63 isolates, 45 [71.4%] were MHT-positive. The NDM-1 gene was detected in 18 of the 63 isolates [28.6%]. All 18 PCR-positive isolates were also MHT-positive. Thus, the sensitivity and specificity of the MHT in detecting NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility are 100% and 40%, respectively

Conclusion: The MHT is a useful test to screen for the presence of NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility. However, due to its rather low specificity, all MHT-positive isolates should be subjected to alternative tests [e.g. PCR] for confirmation, especially if other types of carbapenemases [e.g. KPC] are prevalent

Paecilomyces lilacinus fungaemia in an AIDS patient:the importance of mycological diagnosis

Fungaemia due to Paecilomyces lilacinus is generally not considered in AIDS patients because this condition is not categorised as an AIDS-indicator illness. We report a case of a 25-year-old lady who presented to our hospital with Guillain-Barre Syndrome, with the subsequent development of refractory fungaemia, multi-organ failure and disseminated intravascular coagulopathy. Amphotericin B was given as empirical antifungal therapy. HIV screening was reactive and Paecilomyces lilacinus was isolated from her blood. The fungaemia did not resolve after one week of amphotericin B treatment. The addition of itraconazole was also unsuccessful in clearing the fungaemia. Accurate mycological diagnosis is important in the care of AIDS patients with fungaemia because of the risk of treatment failure with empirical therapy