The efficacy of vacuum-ultraviolet light disinfection of some common environmental pathogens.

BACKGROUND: This study is to elucidate the disinfection effect of ozone producing low-pressure Hg vapor lamps against human pathogens. Ozone producing low-pressure Hg vapor lamps emit mainly 254 nm ultraviolet light C (UVC) with about 10% power of Vacuum-ultraviolet (VUV) light at 185 nm. The combination of UVC and VUV can inactivate airborne pathogens by disrupting the genetic materials or generation of reactive oxygen species, respectively. In this study, inactivation of common bacteria including Escherichia coli ATCC25922 (E. coli), Extended Spectrum Beta-Lactamase-producing E. coli (ESBL), Methicillin-resistant Staphylococcus aureus (MRSA) and Mycobacterium tuberculosis (MTB), and that of influenza A viruses H1N1 and H3N2 under the radiation from ozone producing low-pressure Hg vapor lamps was examined. Log reduction values at different treatment durations were determined. METHODS: In vitro tests were carried out. Various bacterium and virus suspensions were added onto nitrocellulose filter papers and subjected to the illumination from ozone producing low-pressure Hg vapor lamps. The extents of pathogen inactivation at different illumination times were investigated by conducting a series of experiments with increasing duration of illumination. log10 reduction in CFU/ml and reduction at log10(TCID50) were respectively measured for bacteria and viruses. The disinfection effectiveness of this type of lamps against the pathogens under the environment with a moderate barrier to light was therefore evaluated. RESULTS: Ozone producing low-pressure Hg vapor lamp successfully inactivated these human pathogens. Nevertheless, among these pathogens, disinfection of MTB required more intense treatment. In the best tested situation, 3-log10 inactivation of pathogens can be achieved with ≤10 min of VUV treatment except MTB which needed about 20 min. This demonstrated the high resistance against UV disinfection of MTB. CONCLUSIONS: Following the criteria that valid germicidal results can be reflected with 3-log10 inactivation for bacteria, 4-log10 inactivation for viruses and 5-log10 inactivation for MTB, most of the bacteria required ≤10 min of VUV treatment, 20 min for the influenza viruses while MTB needed about 30 min VUV treatment. This indicated that VUV light is an effective approach against different environmental microorganisms.

Performance of the new automated Abbott RealTime MTB assay for rapid detection of Mycobacterium tuberculosis complex in respiratory specimens.

The automated high-throughput Abbott RealTime MTB real-time PCR assay has been recently launched for Mycobacterium tuberculosis complex (MTBC) clinical diagnosis. This study would like to evaluate its performance. We first compared its diagnostic performance with the Roche Cobas TaqMan MTB assay on 214 clinical respiratory specimens. Prospective analysis of a total 520 specimens was then performed to further evaluate the Abbott assay. The Abbott assay showed a lower limit of detection at 22.5 AFB/ml, which was more sensitive than the Cobas assay (167.5 AFB/ml). The two assays demonstrated a significant difference in diagnostic performance (McNemar's test; P = 0.0034), in which the Abbott assay presented significantly higher area under curve (AUC) than the Cobas assay (1.000 vs 0.880; P = 0.0002). The Abbott assay demonstrated extremely low PCR inhibition on clinical respiratory specimens. The automated Abbott assay required only very short manual handling time (0.5 h), which could help to improve the laboratory management. In the prospective analysis, the overall estimates for sensitivity and specificity of the Abbott assay were both 100 % among smear-positive specimens, whereas the smear-negative specimens were 96.7 and 96.1 %, respectively. No cross-reactivity with non-tuberculosis mycobacterial species was observed. The superiority in sensitivity of the Abbott assay for detecting MTBC in smear-negative specimens could further minimize the risk in MTBC false-negative detection. The new Abbott RealTime MTB assay has good diagnostic performance which can be a useful diagnostic tool for rapid MTBC detection in clinical laboratories.

Containment of Clostridium difficile infection without reduction in antimicrobial use in Hong Kong.

Clostridium difficile ribotype 002 with hypersporulating capacity has been increasingly identified in Hong Kong. Proactive infection control measures are important to prevent the establishment of endemicity of C. difficile ribotype 002. A total of 329 patients with healthcare-associated C. difficile infection (CDI) were recruited in our healthcare network between 1 January 2008 and 30 June 2012 in this study. The incidence rates of healthcare-associated CDI per 10,000 admissions and 10,000 patient-days increased significantly by 15.3 and 17.0%, respectively, per quarter (p < 0.001) from 2008 1Q to 2010 1Q by segmented Poisson regression. With the full implementation of enhanced infection control interventions, there was an immediate significant reduction in both healthcare-associated CDI rates per 10,000 admissions and per 10,000 patient-days by 47% (p < 0.001) in 2010 2Q, followed by a further decline of CDI per 10,000 admissions and CDI per 10,000 patient-days by -19.4 and -19.8% from 2010 2Q to 2012 2Q, respectively (p < 0.001), despite a replacement of hand washing with soap and water by alcohol-based hand rub in the healthcare network. The proportion of C. difficile ribotype 002 was not statistically different (34/177, 19.2% vs. 25/152, 16.4%, p = 0.515), and the consumption of broad-spectrum antibiotics presented as divided daily dose per 1,000 acute bed-day occupancy per quarter remained unchanged (140.9 vs. 152.3) before and after infection control interventions. Our results suggested that the reduction of healthcare-associated CDI was attributable to infection control interventions instead of replacement of ribotypes or reduction in antimicrobial selective pressure.

Conformational flexibility determines selectivity and antibacterial, antiplasmodial, and anticancer potency of cationic α-helical peptides.

We used a combination of fluorescence, circular dichroism (CD), and NMR spectroscopies in conjunction with size exclusion chromatography to help rationalize the relative antibacterial, antiplasmodial, and cytotoxic activities of a series of proline-free and proline-containing model antimicrobial peptides (AMPs) in terms of their structural properties. When compared with proline-free analogs, proline-containing peptides had greater activity against Gram-negative bacteria, two mammalian cancer cell lines, and intraerythrocytic Plasmodium falciparum, which they were capable of killing without causing hemolysis. In contrast, incorporation of proline did not have a consistent effect on peptide activity against Mycobacterium tuberculosis. In membrane-mimicking environments, structures with high α-helix content were adopted by both proline-free and proline-containing peptides. In solution, AMPs generally adopted disordered structures unless their sequences comprised more hydrophobic amino acids or until coordinating phosphate ions were added. Proline-containing peptides resisted ordering induced by either method. The roles of the angle subtended by positively charged amino acids and the positioning of the proline residues were also investigated. Careful positioning of proline residues in AMP sequences is required to enable the peptide to resist ordering and maintain optimal antibacterial activity, whereas varying the angle subtended by positively charged amino acids can attenuate hemolytic potential albeit with a modest reduction in potency. Maintaining conformational flexibility improves AMP potency and selectivity toward bacterial, plasmodial, and cancerous cells while enabling the targeting of intracellular pathogens.

Evaluation of the LightCycler methicillin-resistant Staphylococcus aureus (MRSA) advanced test for detection of MRSA nasal colonization.

Rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is crucial for the prevention and control of MRSA infections in health care settings. The LightCycler MRSA Advanced Test (Roche Diagnostics) is a commercially available real-time PCR assay for direct detection of MRSA nasal colonization by targeting of the staphylococcal cassette chromosome mec (SCCmec)-orfX junction. The diagnostic performance of the assay was compared with that of ChromID MRSA agar (bioMérieux) culture and an in-house duplex real-time PCR assay. Among 1,246 nasal swab specimens collected from 2 general hospitals in Hong Kong, 174 (14%) were considered true positive for MRSA. Chromogenic culture and the in-house real-time PCR assay identified 147 (84.5%) and 133 (76.4%) true-positive cases with specificities of 100% and 98.6%, respectively. Based on the target melting temperature (Tm) values (57.0 to 62.0 °C) defined by the manufacturer, the LightCycler MRSA Advanced Test identified only 85 (48.9%) true-positive specimens. Interestingly, an additional 60 (34.5%) true-positive specimens were detected despite atypical Tm values of 55 °C, providing overall sensitivity and specificity values of 83.3% and 99%, respectively. Among isolates with Tm values of 55 °C, most were typed as clonal complex 45 (CC45). By sequence analysis of the SCCmec-orfX junction, characteristic single-nucleotide polymorphisms (SNPs) were identified only in isolates with Tm values of 55°C and not in those with typical Tm values. It is conceivable that those SNPs were located inside the target region of the proprietary hybridization probes, which resulted in a Tm shift in the melting curve analysis. Our study highlights the importance of a global evaluation of commercial kits so that the interpretation algorithm covers different lineages of MRSA clones prevalent in various geographical regions.

In-house human immunodeficiency virus-1 genotype resistance testing to determine highly active antiretroviral therapy resistance mutations in Hong Kong.

OBJECTIVE: To determine the frequency of highly active antiretroviral therapy resistance mutations in the viral pol gene of human immunodeficiency virus-1 (HIV-1) genotypes that circulate in Hong Kong, by means of an in-house HIV-1 genotyping system. DESIGN: Retrospective study. SETTING: Two HIV clinics in Hong Kong. PATIENTS: A modified in-house genotyping resistance test was used to sequence the partial pol gene in 1165 plasma samples from 965 patients. The performance of our test was cross-compared with the US Food and Drug Administration-approved ViroSeq HIV-1 genotyping system. The results of genotyping were submitted to the Stanford HIV-1 drug resistance database for analysis. RESULTS: The cost-effective in-house genotypic resistance test (US$40) demonstrated comparable performance to the US Food and Drug Administration-approved ViroSeq system. The detection limit of this in-house genotypic resistance test could reach 400 copies/mL for both HIV-1 subtype B and CRF01_AE, which were the predominant genotypes in Hong Kong. Drug resistance mutations were detected only in post-treatment samples from treatment-failure patients. However, there was no significant difference in the frequency of drug resistance mutations between subtype B and CRF01_AE. CONCLUSION: Our cost-effective in-house genotypic resistance test detected no significant difference in drug resistance-related mutations frequencies between HIV-1 subtype B and CRF01_AE in Hong Kong. A drug resistance-related mutations database for different HIV-1 genotypes should be established in Hong Kong to augment guidance for HIV treatment.

Truncated Rv2820c enhances mycobacterial virulence ex vivo and in vivo.

Three hypervirulent strains of Mycobacterium tuberculosis isolated from patients suffering from tuberculous meningitis were shown to grow more rapidly inside human macrophages in our previous study. In the current investigation, genomic polymorphisms in these hypervirulent strains were examined using microarray-based comparative genomic hybridization. Among the five genomic polymorphisms identified, two are in-frame deletion (Rv0071/4 and Rv0613c/6c), two are frameshift deletion (Rv1758' and Rv2820c'), and one is gene replacement (Mb3159). The five genomic polymorphisms were transformed into Mycobacterium smegmatis strain mc(2)155 and the survivability of recombinants inside the human monocytic cell line THP-1 was measured. Interestingly, only the recombinant possessing the Rv2820c' survived significantly better than the vector control after 6 h of ex vivo infection (P < 0.001, one-way ANOVA). The Rv2820c' was later transformed into Mycobacterium marinum strain M and the recombinant was used to infect zebrafish. The in vivo infection also showed that the zebrafish infected with the recombinant possessing the Rv2820c' died significantly faster than the vector control (P = 0.006, log-rank test). The 3' truncation in the Rv2820c' was caused by the Beijing/W-defining deletion RD207 and is commonly found in the Beijing/W strains. The current study demonstrated that the truncated Rv2820c of Beijing/W strains could enhance mycobacterial virulence ex vivo and in vivo. This enhancement, however, was not observed for the intact Rv2820c of the non-Beijing/W strains. The presence of the 3' truncated portion of Rv2820c may interfere with overall protein folding and render the Rv2820c of the non-Beijing/W strains non-functional.

Clostridium difficile isolates with increased sporulation: emergence of PCR ribotype 002 in Hong Kong.

We identified a predominant clone of Clostridium difficile PCR ribotype 002, which was associated with an increased sporulation frequency. In 2009, 3,528 stool samples from 2,440 patients were tested for toxigenic C. difficile in a healthcare region in Hong Kong. A total of 345 toxigenic strains from 307 (13.3%) patients were found. Ribotype 002 was the predominant ribotype, which constituted 35 samples from 29 (9.4%) patients. The mean sporulation frequency of ribotype 002 was 20.2%, which was significantly higher than that of the 56 randomly selected ribotypes other than 002 as concurrent controls (3.7%, p < 0.001). Patients carrying toxigenic ribotype 002 were more frequently admitted from an elderly home (p = 0.01) and received more ß-lactam antibiotics in the preceding 3 months compared with the controls (p = 0.04) . The identification of toxigenic ribotype 002 in 2009 was temporally related to a significant increase in both the incidence of toxigenic C. difficile from 0.53 to 0.95 per 1,000 admissions (p < 0.001) and the rate of positive detection from 4.17% to 6.28% (p < 0.001) between period 1 (2004-2008) and period 2 (2009). This finding should alert both the physician and the infection control team to the establishment of and possible outbreaks by ribotype 002 in our hospitals, as in the case of ribotype 027.

Prevalence of hepatitis B genotype and viral basic core promoter and precore mutations among teenagers in Macao: relationship with hepatocellular carcinoma development.

Chronic hepatitis B virus (HBV) infection is a global problem and over 75% of cases are reported in the Asia Pacific region. Infection can lead to progressive liver disease, cirrhosis and hepatocellular carcinoma (HCC). Previous studies suggest the prevalence of HBV carriers in Macau to be approximately 10% of the population. This study aims to investigate the prevalence of HBV genotypes among HBV-positive teenagers in Macao and the prevalence of base core promoter (BCP) and precore (PreC) mutations in the viral genome. In addition, through monitoring aminotransferase and alpha-fetoprotein, it aims to investigate relationships among HBV genotypes, BCP/PreC mutations and HCC development. This study recruited 1991 teenagers in Macau in 2008, and the PreS1/S2, BCP and PreC region of the HBV genome from 34 HBsAg-positive subjects were amplified and sequenced to determine HBV genotype and presence of HCC-associated mutations. Results suggested that the average rate of HBV infection among secondary school teenagers in Macao is low, and HBV genotype B and C viruses were found to predominate in Macao. The BCP/PreC mutations A1762T, G1764A, G1896A and C1766T were identified in 2.9-11.7% of subjects. However, no significant relationship was observed between HBV genotype, BCP/PreC mutations and HCC development.

Microbiology of odontogenic bacteremia: beyond endocarditis.

SUMMARY: The human gingival niche is a unique microbial habitat. In this habitat, biofilm organisms exist in harmony, attached to either enamel or cemental surfaces of the tooth as well as to the crevicular epithelium, subjacent to a rich vascular plexus underneath. Due to this extraordinary anatomical juxtaposition, plaque biofilm bacteria have a ready portal of ingress into the systemic circulation in both health and disease. Yet the frequency, magnitude, and etiology of bacteremias due to oral origin and the consequent end organ infections are not clear and have not recently been evaluated. In this comprehensive review, we address the available literature on triggering events, incidence, and diversity of odontogenic bacteremias. The nature of the infective agents and end organ infections (other than endocarditis) is also described, with an emphasis on the challenge of establishing the link between odontogenic infections and related systemic, focal infections.

Preconditioning with Porphyromonas gingivalis lipopolysaccharide may confer cardioprotection and improve recovery of the electrically induced intracellular calcium transient during ischemia and reperfusion.

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis lipopolysaccharide (LPS) is a ligand for cell surface toll-like receptors (TLR), TLR2 and TLR4 while stimulation of either leads to cardioprotection. We hypothesized that: (1) pretreatment with P. gingivalis LPS at appropriate concentrations would induce cardioprotection against injury induced by ischemia and reperfusion; and (2) P. gingivalis LPS pretreatment at cardioprotective concentrations may reduce Ca(2+) overload, which is a precipitating cause of injury, and improve recovery of contractile function. MATERIAL AND METHODS: Male Sprague-Dawley rats were randomly selected to receive intraperitoneal saline or hot phenol-water-extracted P. gingivalis LPS at 0.2, 0.5, 1.0, 2.0 or 4.0 mg/kg 24 h before the experiment. The hearts were isolated and subjected to regional ischemia by coronary artery ligation followed by reperfusion. In isolated rat ventricular myocytes, the cytosolic Ca(2+) level and the electrically induced intracellular calcium (E[Ca(2+)](i)) transient, which reflects contractile function, were determined after pretreatment with a cardioprotective dose of P. gingivalis LPS. RESULTS: Pretreatment with 0.5 mg/kg P. gingivalis LPS significantly reduced, while pretreatment with 1.0-4.0 mg/kg significantly increased infarct size. The Ca(2+) overload induced by ischemia-reperfusion was attenuated in myocytes from rats pretreated with 0.5 mg/kg P. gingivalis LPS. Pretreated myocytes also showed an increased amplitude of the E[Ca(2+)](i) transient, no prolongation of the time to reach the peak E[Ca(2+)](i) transient and shorter 50% decay time during reperfusion. CONCLUSION: At a dosage of 0.5 mg/kg, P. gingivalis LPS confers cardioprotection against ischemia-reperfusion-induced injury and improved intracellular E[Ca(2+)](i) transient recovery, hence improving myocyte contractile recovery.

Exploring the oral bacterial flora: current status and future directions.

OBJECTIVE: The oral cavity forms an indispensable part of the human microbiome, for its unique and diverse microflora distributed within various niches. While majority of these organisms exhibit commensalism, shifts in bacterial community dynamics cause pathological changes within oral cavity and distant sites. The aim of this review was to appraise the current and emerging methods of detecting bacteria of the oral cavity paying particular attention to the cultivation independent methods. DESIGN: Literature pertaining to cultivation based and cultivation independent methods of oral bacterial identification was reviewed. METHODS: The specific advantages and disadvantages of cultivation based, microscopic, immunological and metagenomic identification methods were appraised. RESULTS: Because of their fastidious and exacting growth requirements, cultivation based studies grossly underestimate the extent of bacterial diversity in these polymicrobial infections. Culture independent methods deemed more sensitive in identifying difficult to culture and novel bacterial species. CONCLUSION: Apart from characterizing potentially novel bacterial species, the nucleic acid sequence data analyzed using various bioinformatics protocols have revealed that there are in excess of 700 bacterial species inhabiting the mouth. Moreover, the latest pyrosequencing based methods have further broadened the extent of bacterial diversity in oral niches.

Evaluation of in-house and commercial genotyping assays for molecular typing of hepatitis C virus in Hong Kong.

This study aims to evaluate genotyping assays for hepatitis C virus (HCV). An in-house nucleic acid sequencing method is performed in parallel with the Roche Linear Array HCV genotyping test on 73 HCV-positive (66 clinical samples and seven proficiency testing quality control samples) and 12 HCV-negative samples (11 clinical samples and one proficiency testing sample). The performance of the in-house method was comparable with that of the Roche assay (concordance rate: 89.4%). Discordant results included four mixed infections missed by the in-house method, two false-negatives with the Roche assay, and three discrepant results. The in-house method exhibited a higher resolution (subtype vs. genotype level) at a lower running cost (25% of the commercial assay). The in-house method was also used to genotype 375 HCV clinical isolates to determine the genotypic distribution of HCV in Hong Kong between 2005 and 2008. A total of 441 (52.8%) clinical isolates proved to be genotype 1, which shows a poorer response to interferon therapy. Genotype 6 was the next most common (32.0%). Prevalence of genotypes 2 and 3 was 7.7% and 6.6%, respectively, and prevalence of genotypes 4 and 5 was 0.9% and 0%, respectively. Although the in-house nucleic acid sequencing method failed to detect a few cases of mixed HCV infection, its high resolution and low running cost make it suitable for surveillance and outbreak investigation.

Outbreak of intestinal infection due to Rhizopus microsporus.

Sinopulmonary and rhinocerebral zygomycosis has been increasingly found in patients with hematological malignancies and bone marrow transplantation, but intestinal zygomycosis remains very rare in the literature. We investigated an outbreak of intestinal infection due to Rhizopus microsporus in 12 patients on treatment for hematological malignancies over a period of 6 months in a teaching hospital. The intake of allopurinol during hospitalization (P < 0.001) and that of commercially packaged ready-to-eat food items in the preceding 2 weeks (P < 0.001) were found to be independently significant risk factors for the development of intestinal zygomycosis. A total of 709 specimens, including 378 environmental and air samples, 181 food samples, and 150 drug samples, were taken for fungal culture. Among them, 16 samples of allopurinol tablets, 3 prepackaged ready-to-eat food items, and 1 pair of wooden chopsticks were positive for Rhizopus microsporus, which was confirmed by ITS1-5.8S-ITS2 rRNA gene cluster (internal transcribed spacer [ITS]) sequencing. The mean viable fungal counts of allopurinol obtained from wards and pharmacy were 4.22 x 10(3) CFU/g of tablet (range, 3.07 x 10(3) to 5.48 x 10(3)) and 3.24 x 10(3) CFU/g of tablet (range, 2.68 x 10(3) to 3.72 x 10(3)), respectively, which were much higher than the mean count of 2 x 10(2) CFU/g of food. Phylogenetic analysis by ITS sequencing showed multiple clones from isolates of contaminated allopurinol tablets and ready-to-eat food, of which some were identical to patients' isolates, and with one isolate in the cornstarch used as an excipient for manufacture of this drug. We attempted to type the isolates by random amplification of polymorphic DNA analysis, with limited evidence of clonal distribution. The primary source of the contaminating fungus was likely to be the cornstarch used in the manufacturing of allopurinol tablets or ready-to-eat food. Rhizopus microsporus is thermotolerant and can multiply even at 50 degrees C. The long holding time of the intermediates during the manufacturing process of allopurinol amplified the fungal load. Microbiological monitoring of drugs manufactured for highly immunosuppressed patients should be considered.

Detection and characterisation of extended-spectrum beta-lactamases among blood stream isolates of Enterobacter species in Hong Kong.

1. Extended-spectrum beta-lactamase(ESBL) resistance in Enterobacter spp may be under-recognised. 2. Detection methods for ESBL resistance in Enterobacter spp may need to be modified.

Comparison of T-Spot.TB and tuberculin skin test among silicotic patients.

In the present study, T-Spot.TB and the tuberculin skin test (TST) were compared in the screening of latent tuberculosis infection among silicotic patients. A conditional probability model was used to compare the potential clinical utilities of T-Spot.TB and TST performed on 134 silicotic subjects from December 1, 2004 to January 31, 2007. Data from a historical cohort were also reanalysed for further comparison. Agreement with T-Spot.TB was best using a TST cut-off of 10 mm. Age >or=65 yrs independently predicted a tuberculin reaction <10 mm (odds ratio = 3), but not a negative T-Spot.TB response. Lower measures of agreement were observed among current smokers and those aged >or=65 yrs. Tuberculin reaction size was well correlated with both early secretary antigenic target 6 and culture filtrate protein 10 spot counts, except among current smokers. Within the current estimates of sensitivity (88-95%) and specificity (86-99%) for T-Spot.TB, the positive likelihood ratio for T-Spot.TB test would be substantially higher (6.29-95.0 versus 1.65-1.94) and negative likelihood ratio substantially lower (0.05-0.14 versus 0.32-0.41) than the corresponding ratios for the tuberculin test. A low tuberculosis risk differential was similarly observed between tuberculin-negative and untreated tuberculin-positive subjects in the historical cohort. T-Spot.TB is likely to perform better than tuberculin test in the screening of latent tuberculosis infection among silicotic subjects.

Evaluation of NucliSens EasyQ HIV-1 assay for quantification of HIV-1 subtypes prevalent in South-east Asia.

BACKGROUND: Monitoring anti-retroviral therapy requires that viral load assays for human immunodeficiency virus type 1 (HIV-1) be applicable to diverse HIV-1 subtypes. OBJECTIVES: To evaluate NucliSens EasyQ HIV-1 assay for quantitation of common HIV-1 subtypes prevalent in South-east Asia. STUDY DESIGN: One hundred and nineteen plasma samples collected in Hong Kong and Cambodia were used to compare the performance of NucliSens EasyQ HIV-1 and COBAS Amplicor HIV-1 Monitor version 1.5 assays. Viral RNA extracted from the NucliSens MiniMAG was also used for HIV-1 subtyping. RESULTS: Performance of NucliSens EasyQ correlated well with COBAS Amplicor (r=0.777, p<0.001) and the small mean difference (0.0462log(10)IU/mL) obtained in the Bland and Altman model indicated good agreement between two assays. The NucliSens EasyQ assay demonstrated a 95% sensitivity at 500IU/mL and 100% specificity. Reproducibility of this assay was within log(10)2-4IU/mL and had a coefficient of variation between 2.3% and 10.4%. Among the 109 specimens included in the analysis, HIV-1 subtyping identified 64 CRF01_AE, 38 subtype B, 3 subtype C, 3 CRF07_BC and 1 subtype G viruses. CONCLUSIONS: Performance of NucliSens EasyQ was comparable to COBAS Amplicor for HIV-1 viral load monitoring. RNA extracts from NucliSens MiniMAG could be used for HIV-1 viral load monitoring, subtyping and drug resistance mutations detection. Our findings highlight the versatility of both NucliSens EasyQ and COBAS Amplicor in monitoring prevalent subtypes and rare circulating recombinant forms (CRFs) in the South-east Asia region.