Production and application of lyophilized urine samples used in microbiology external quality assessment programme in Vietnam

Original Research

Abstract

Introduction: The external quality assessment (EQA) for microbiological laboratories is one of the most commonly used services for quality assurance. In Vietnam, the majority of EQA samples are imported from foreign markets, involving high costs, complicated procedures and further making it difficult to ensure quality in terms of transport and management. The objective of this study was to develop a process for producing lyophilized urine samples containing pathogens (Escherichia coli and Enterococcus faecalis), evaluating the homogeneity and stability of the produced samples and the subsequent application of these samples in the launching trial program of the clinical microbiology program.

Methods: The production process of was established according to ISO Guide 34:2009. The homogeneity and stability of production samples were evaluated according to the guidance of ISO 13528:2015. Produced samples were preserved at 2-8°C and assessed for stability after 2, 4, 6, 8, 10, and 12 weeks. Samples were subsequently utilized in the clinical microbiology EQA program, wherein they were sent to 26 laboratories located in several different regions across Vietnam.

Results: The production process thus conceived comprised eight steps that ensured the homogeneity of the samples produced. Two sets of quality samples were produced and stability within12 weeks. Approximately 92% of the laboratories met the set target.

Conclusions: The eight-step process to produce presumptive lyophilized urine samples has successfully developed. The produced samples reach the criteria for EQA samples and suitable to apply on clinical microbiology EQA scheme at national scale.

Graphical abstract

Lactic acidosis had developed in diabetic patients receiving herbal therapy

Original Research

Abstract

Introduction: Herbal antidiabetic products are popular in Vietnam. Many cases have presented to hospitals with severe lactic acidosis, shock and were ultimately fatal. We reviewed the clinical findings of these patients for factors that contributed to their illness and death, and analyzed the ingredients contained in these herbal products sold for diabetic treatment.

Method: This was a single-center, retrospective, observational case series. Data were collected on all cases who presented with severe lactic acidosis after use of traditional herbal anti-diabetic pills, over the two-year time period 2018 – 2019. Past medical histories and clinical findings were reviewed. Samples of the herbal anti-diabetic products, and patient blood and urine were analyzed.

Results: A total of 18 cases of severe lactic acidosis associated with use of herbal anti-diabetic pills were reviewed. These patients had a diagnosis of diabetes for an average of 9 years (9.4 ± 4.6 years). The use of these herbals for blood glucose control ranged from one month to 8 years; approximately 50% of these patients consumed these products over a year’s time. Only two cases had combined herbal products and metformin 500 mg. A total mean of herbal pills consumed was 9 (SD ± 8); patients commonly took combinations of 2 different colored tablets. Major manifestations included gastrointestinal disorders, severe metabolic acidosis (pH = 6.85 ± 0.22, HCO3- = 4.4 ± 2.6), with multi-organ failure and shock on admission. Hyperlactatemia was present in all cases (195 ± 74 mg/dL). For lactate removal and acidosis correction, intermittent hemodialysis or continuous renal replacement therapy was performed, ranging from 2 hours to 72 hours depending on the severity of lactic acidosis and patient need. The mortality rate was 33.3% and all these patients became hypoglycemic, either at initial presentation or during treatment. 22 samples of herbal pills were available for testing that contained the biguanides metformin and phenformin, with a higher concentration of phenformin than metformin if both were present, Phenformin was presented in all samples. Arsenic was found in two samples.

Conclusion: Biguanides are an effective treatment for diabetes and were added to traditional herbal pills sold and used for blood glucose control. Many users of these products are doing so because of the cost and perception of the safety of natural remedies. Biguanide poisoning may still occur even in patients without renal impairment.

Graphical abstract

Healthcare associated pneumonia: An old concept at a hospital with high prevalence of antimicrobial resistance

Original Research

Abstract

Background: One of several reasons that the concept of healthcare-associated pneumonia (HCAP) was dismissed was the same presence of multidrug resistant organism (MDRO) between community-acquired pneumonia and HCAP at countries with the low prevalence of antimicrobial resistance (AMR). However, this finding could be unsuitable for countries with the high rates of AMR.

Methods: A prospective observational study was conducted at the respiratory department of Cho Ray hospital from September 2015 to April 2016. All adult patients suitable for community acquired pneumonia (CAP) with risk factor for healthcare-associated infection were included.

Results: We found out 130 subjects. The median age was 71 years (interquartile range 57-81). The male/female ratio was 1.55:1. Prior hospitalization was the most common risk factor for healthcare-associated infection. There were 35 cases (26.9%) with culture-positive (sputum and/or bronchial lavage). Isolated bacteria included Pseudomonas aeruginosa (9 cases), Klebsiella pneumoniae (9 cases), Escherichia coli (4 cases), Acinetobacter baumannii (6 cases), and Staphylococcus aureus (7 cases) with the characteristic of AMR similar to the bacterial spectrum associated with hospital-acquired pneumonia.

Conclusion: MDROs were detected frequently in CAP patients with risk factor for healthcare-associated infection at the hospital with the high prevalence of AMR. This requires the urgent need to evaluate risk factors for MDRO infection in community-onset pneumonia when the concept of HCAP is no longer used.

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Pheochromocytoma: Impact of genetic testing on clinical practice in Vietnam

Original Research

Abstract

Introduction: Germline mutations in predisposing genes have been found in 30-40% of pheochromocytoma/paraganglioma patients. Screening for inherited genetic mutations provide clinicians with mutation-positive patient management strategies in addition to identifying family members at risk of disease. However, genetic testing for pheochromocytoma has not been performed widely in Vietnam.

Methods: Seven patients diagnosed with pheochromocytoma in Vietnam underwent germline genetic testing in known pheochromocytoma-associated genes by direct sequencing. When a germline mutation was identified the first-degree relatives were counseled and offered genetic testing for the inherited mutation.

Results: Mutations were found in five of seven cases and all mutations were in RET proto-oncogene codon 634 indicating a high risk of developing aggressive medullary thyroid cancer and in some cases leading to prophylactic thyroidectomy as recommended.

Conclusions: Genetic testing plays an essential role in the clinical management of pheochromocytoma patients. Genetic results have significantly changed the clinical approach in these patients and identified ‘at risk’ family members.

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Validation of a simple HPLC method to quantify mycophenolic acid concentrations in human plasma

Original Research

Abstract

Introduction: Mycophenolic acid (MPA) is an active metabolite of mycophenolate mofetil and mycophenolate sodium which are widely prescribed to prevent organ rejection after solid organ transplantations. However, MPA induced many side effects on gastrointestinal tract and haematological system.

Objectives: The purpose of this study is to establish a high-performance liquid chromatography (HPLC) method to determine the MPA concentration in plasma in order to optimize the treatment efficacy of MPA or apply to bioequivalence studies. MPA and visnadine (as an internal standard) were extracted from plasma samples with methanol by solid phase extraction using Osis HLB 1cc cartridge. 10 µL of sample extract was injected onto LiChroCART®125-4 (C18 reversed-phase column) at 43 °C on a Waters 2695 XE system. The signals were detected by PDA detector (photodiodes array) at 254 nm. The mobile phase was a mixture of acetonitrile and phosphate buffer (pH 3) with a flow rate of 1 mL/min. The validation criteria included: selectivity, linearity, accuracy, precision, recovery, lower limit of quantification.

Results: Total chromatographic runtime was 15 min. MPA and visnadine were found at 6.45 and 10.79 min, respectively. MPA concentrations were in the linear range from 0.25 to 50 µg/mL. The coefficient of variation (CV) of mean intra-day and inter-day precision levels for MPA was less than 7.5%. The lower limit of quantification was 0.25 µg/mL. No interference was found in the assay.

Conclusion: A simple and reliable HPLC method was developed to quantify the MPA concentration in plasma.

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Actinomycosis of bilateral psoas muscle: a case report

Case Study

Abstract

Actinomycosis is an underreported chronic invasive disease caused by Actinomyces spp. In that group of diseases, pelvic actinomycosis is very rare and most of the cases reported in the literature have shown unilateral psoas muscle involvement. We report a 35-year-old woman with a retroperitoneal mass located in the left psoas muscle that makes abdominal tenderness and difficulty in walking. She had a 7-year history of intrauterine device which had been removed one month just before this event. After undergoing two laparotomies to perform a biopsy with undetermined results, she developed a new mass in the right psoas muscle which was similar to the left one. On the third attempt, the histopathology revealed yellow sulfur granules of Actinomyces which reacted positively with periodic acid Schiff and Grocott’s dye. After three months of treatment with Amoxicillin plus Clavulanic acid, her abscesses were completely resolved. Actinomycosis should always be included in the diagnostic list in patients with a pelvic mass and a history of intrauterine device.

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