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MOST RECENT ARTICLES

Peer reviewed ORIGINAL ARTICLE
Open Access

In vitro antibacterial activity of azole antifungals against Carbapenem-Resistant Enterobacteriaceae
SP Radebe | TS Ndlovu | DR Prakaschandra
Published online: December 2018

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Introduction: The frequency of serious bacterial infections has increased due to the high prevalence of HIV, contributing to the increasing rates of multi-drug organisms which include carbapenem-resistant Enterobacteriaceae (CRE). This has resulted in higher use of immunosuppressive and cytotoxic drugs to treat serious bacterial infections and optimal treatment for infections caused by CRE remains unknown. The benefits of azole antifungals and its derivatives have become very topical due to their diverse spectrum of pharmacological properties, but its efficacy has not been tested in the South African context. The aim of this study was to determine the antibacterial effects of azole antifungals against CRE.
Method: Different concentrations of azole antifungals (ketoconazole, metronidazole and fluconazole) were used to prepare sensitivity discs and four pathogenic strains of CRE (K. pneumoniae, E. coli, S. marcesens and C. freundii). These were obtained from Lancet Laboratory in Durban and were used to determine the antibacterial activity of the selected azole antifungals, using: Disc Diffusion, Modified Agar Diffusion and Minimum Inhibition Concentration (MIC) method, as described by Bauer et al. 1966.
Results: Antimicrobial Susceptibility Testing revealed that azoles have no inhibition activity against CRE test organisms and biochemical tests also demonstrated that azoles have no adverse effects on the CRE organisms.
Conclusion: Although the results obtained in this study indicated no activity of azoles against CRE, clinical studies are still necessary for the modification of the azole substituents and synthesis of azole derived drugs to confirm and optimise the antibacterial efficacy of these compounds.


Peer reviewed ORIGINAL ARTICLE
Open Access

The importance of including maternal profiles in paternity testing – three cases of possible false inclusion with duo-only testing
Y Harris | D Welgemoed
Published online: December 2018

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There are frequent requests for duo paternity tests thus increasing the possibility of false paternity inclusions. The aim of this study was to identify possible false inclusions when comparing the duo to the trio paternity profile to see if there is a discrepancy in the results when using 15-loci autosomal short tandem repeat (STR) analysis. We concluded that wrongful inclusions would have occurred in duo paternity profiles in three cases out of 240 trio exclusions. Paternity probabilities between 95.0688215064% and 99.99964871% were calculated on the duos. We demonstrated how duo results were changed from an inclusion to a definite exclusion when the mother’s DNA profile was added to the test, showing the importance of the mother’s profile in paternity testing and the risk of false inclusions in duo cases. These findings support the literature where false inclusions are reported in a paternity test where the mother’s profile is omitted, as well as the recommendation for 3 or more mismatches as an exclusion criterion.

Peer reviewed ORIGINAL ARTICLE
Open Access

The automated schistocyte count requires microscopic confirmation
Dr A Baiden | Dr E Schapkaitz
Published online: December 2018

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Background: The automated fragmented red cell (FRC) is a promising diagnostic tool for the rapid diagnosis of patients with a suspected thrombotic micro-angiopathy (TMA).
Aim: To evaluate the FRC in comparison to the microscopic schistocyte percentage in order to determine its diagnostic utility.
Methods: Schistocytes were evaluated in 136 samples by microscopy by two competent morphologists according to International Council for Standardisation in Haematology (ICSH) recommendations. This was compared with the FRC on the Sysmex XN-9000 (Sysmex Corporation, Kobe, Japan). The degree of agreement was measured using the Bland and Altman method and Deming-regression statistical methods.
Results: Schistocytes were observed in patients with TMA (8.82%), malignancies (11.03%), haemodialysis (34.56%), haemoglobinopathies (8.82%), nutritional anaemias (13.24%) and in neonates (1.47%). The correlation co-efficient between the two morphologists was 0.97 (CI, 0.92 to 1.01) and the mean of the differences was -0.02 (CI, -0.53 to 0.50). The Sysmex overestimated the schistocyte count (2.61, CI, 2.15 to 3.07) and revealed a poor correlation with microscopy (0.21 CI, 0.05 to 0.38). There was no correlation between the percentage of microcytic (%Micro-R) and hypochromic red cells (%Hypo-He) and the FRC.
Conclusion: This study confirms that observer bias between morphologists can be reduced by implementing the ICSH guidelines. Measurement of the automated FRC by the Sysmex XN 9000 analyser overestimated the schistocyte percentage. The FRC requires confirmation by microscopy.

Peer reviewed ORIGINAL ARTICLE
Open Access

Assessment of organ dysfunction and laboratory parameters in chronic Nyaope users
AA Khine | KE Mokwena | V Moodley
Published online: December 2018

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Nyaope is a novel psychoactive mixture of drugs unique to South Africa’s townships. A mixture of caffeine, paracetamol, opiates, sedatives, psychoactive drugs as well as antibiotics and antiretroviral drugs were identified using Time of Flight Mass Spectrometry. The Nyaope users frequently complained of severe chest and abdominal pain, excessive drowsiness, vomiting and diarrhoea with progressive weight loss. However, the effect of Nyaope on various body systems has not been verified.
The purpose of this study was to investigate the status of liver, kidney, endocrine function, and haematological parameters in chronic Nyaope users. Ninety eight users participated for laboratory analyses of liver, kidney, thyroid and gonadal functions, blood counts and immunophenotyping. From these, 86.7% of users showed abnormalities in the laboratory tests performed, and 10.2% to 31.6% with possible specific organ dysfunctions.
In conclusion, Nyaope users were found to have abnormal laboratory parameters that may be suggestive of organ dysfunctions, occult infections, and possible bone marrow suppression and would require further investigations.

Peer reviewed ORIGINAL ARTICLE
Open Access

Ethical challenges in medical technology use
A Nicolaides
Published online: December 2018

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As such, medical technology, serves the purpose of seeking to enhance the quality of human life. In recent times, the effects of societal and ethical as well as legal aspects of technologies in medicine have come under the spotlight. Clinicians invariably use a wide assortment of technologies within the spectrum of laboratory medicine in diagnosing, treating and assessing the care of patients. These assortments of technologies play a pivotal role in healthcare and one could argue that medical practice is now fundamentally dependent on these technologies. While medical technology should be reducing the overall cost of treating patients due to its ability to enhance prevention by deriving custom-made therapies, this is not the case. Medical technology is conversely becoming more expensive, and as it is use increases, so does the cost of healthcare for patients at all levels of the socio-economic spectrum. The increasing use of high-end technology is very expensive, thereby increasing the cost of for example, laboratory testing. These ever increasing costs are beyond the reach of the average South African citizen who cannot afford the exorbitant costs of medical aid.
This article addresses the ethicality of what is seemingly an unjust practice. It asserts that there should be greater efforts not only by the industry to develop suitable affordable technologies, but also by the various pathology laboratory sectors in accordance with the various medical needs and priorities of South African society. The local healthcare market is undergoing substantial cost constraints. If any new offerings are to be adopted by all healthcare providers, they first need to validate the cost in contrast to the assessable improvement such offerings can provide to improve or stabilise patient healthcare. The ever increasing cost of healthcare is unaffordable for the majority of South African citizens. All this can be construed as unethical practice since it increases medical costs for other citizens, as medical aid schemes are obliged to pass on these exorbitant costs incurred by them, to their members.

Peer reviewed ORIGINAL ARTICLE
Open Access

The effect of isoniazid preventative therapy on the occurrence of tuberculosis in Lesotho, Southern Africa
E Mugomeri | D Olivier | WMJ van den Heever
Published online: December 2018

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Lesotho faces a catastrophic syndemic of HIV and tuberculosis (TB). In 2011, the government of Lesotho launched isoniazid preventive therapy (IPT) as a once-off intervention to reduce the occurrence of TB in HIV-positive people. This study evaluated the effectiveness of IPT and the durability of its effectiveness based on Cox’s proportional hazards regression analysis of 2 955 records randomly sampled from six districts of Lesotho. The overall TB incidence rate was 2.0 per 100 person-years in 12 208 person-years. Thirty-nine (15.9%, n=246) patients developed TB after IPT. TB incidences per 100 person-years by timing of IPT were as follows: (a) IPT before ART (1.7); (b) IPT after ART (1.8); (c) no IPT (2.6); (d) IPT within one year of ART commencement (1.3) and (e) IPT 3-5 years after ART initiation (2.3). Gender, baseline World Health Organisation (WHO) clinical staging, district category and time to IPT relative to ART commencement emerged as significant predictors of TB occurrence. Increasing time to IPT by one six-month interval increased the risk of contracting TB by between 6% and 59. Further, IPT effectiveness rapidly deteriorated after four years. This indicates that delayed IPT after ART commencement significantly affects the effectiveness of this intervention. The need to consider booster doses of IPT cannot be overemphasised.

Peer reviewed ORIGINAL ARTICLE
Open Access

The antibacterial and antioxidative stress activities and characterisation of Asparagus laricinus aqueous extract
S Fuku | S Mashele
Published online: December 2018

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Background: Research indicates an increase in drug resistance to pathogenic human bacteria, despite the increase in synthetic antimicrobial drugs. As a result, medicinal plants are proving to be rich resources of constituents which can be used in drug development and synthesis of antimicrobial agents and/or their derivatives. Many of therapeutic drugs e.g. antimicrobial, anti-cancer and antioxidants have compounds extracted from plants as their primary active ingredients or molecules of plant origin serve as blue prints for synthetic or partially synthetic drugs.
Methods: The antimicrobial activity of the Asparagus laricinus aqueous extract was evaluated by determination of minimum inhibitory concentration against laboratory strains of both gram-positive (Bacillus subtilis, Streptococcus pneumonia and Staphylococcus aureus) and gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Proteus vulgaris). The micro-plate assays based on iodo-nitrotetrazolium violet indicator was used to evaluate cell viability. Antioxidative stress activity of the extract was determined using Saccharomyces cerevisiae (BY4742) as the model eukaryotic system, while constitutes of the plant extract were profiled using LC/MS.
Results: This study reports on the anti-bacterial and antioxidative stress activity of Asparagus laricinus. It was observed that 50µg/ml of the plant extract was the (MIC) for the gram-positive bacteria Bacillus subtilis, Streptococcus pneumonia and Staphylococcus aureus. While100µg/ml that was required for other gram-negative strains, Pseudomonas aeruginosa, Escherichia coli and Proteus vulgaris and Staphylococcus aureus was inhibited by 25µg/ml of the plant extract. The plant extract protected Saccharomycescerevisiae (BY4742) cells from oxidative stress when the cells were incubated with 10mM (H2O2) for 1.5 hours. The phyto constituents of the plant extract were profiled using LC/MS and four major peaks were assigned chemical formulae.
Conclusions: Asparagus laricinus water extract showed antimicrobial and antioxidative stress activities. LC/MS profile of major constituents of the plant extract revealed the presence of an alkaloid similar to 4-thiazolidinones, known to have important biological activities.


Peer reviewed ORIGINAL ARTICLE
Open Access

Simultaneous analysis of plasma lactate and pyruvate in whole blood using a UV/visible spectrophotometer; application in hypovolemic shock and hypoxia
WV Dube | LC Bekker | AA Khine
Published online: December 2018

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Background: Unavailability of pyruvate quantification at the majority of the National Health Laboratory Service (NHLS) laboratories in South Africa prevents patient’s access to a lactate-to-pyruvate ratio (L:P ratio) determination. Thus the diagnosis and prognosis of hypoxemic conditions can be compromised. To obtain the ratio, lactate is measured; either using heparinised blood with a blood gas analyser as a point of care test (POCT) or in a sodium fluoride (NaF)/ potassium oxalate plasma on an automated laboratory analyser. Measurement of pyruvate concentrations in serum are offered at certain referral laboratories using a manual method and requires pre-packedclot enhanced serum tube (red top) with perchloric acid (PCA). The use of two different types of samples and additional sample preparation for L:P ratio is inconvenient for the patient, clinicians and alsoposes a risk for pre-analytical errors. This study aimed to determine if two tests can be consolidated in one NaF plasma tube whilst maintaining the perchlorate de-proteinisation to preserve pyruvate.
Objectives: To compare pyruvate concentrations in the serum and plasma (anticoagulant: NaF) samples using a UV/visible spectrophotometer to assess the validity of using plasma for pyruvate analysis.
Methods: Fifty patients with high whole blood lactate concentrations using a point of care analyzer at the Intensive Care Unit (ICU) were included in the study. Twenty-five specimens from a health control group were also included. Pyruvate was measured in perchloric acid treated serum and plasma samples using a UV/Visible spectrophotometer. The results of both types of samples were compared in both patient and control groups.
Results: In the patient group, a correlation coefficient of R2 between plasma and serum pyruvate results was 0.35 while in the control group was 0.36 demonstrating poor correlation. The mean of the serum pyruvate concentrations in the patient group was 0.151 mmol/L, and in the plasma samples was 0.065 mmol/L with P=0.00. The mean pyruvate concentration in the serum samples of the control group was 0.108 mmol/L and in the plasma samples was 0.041 mmol/L with the P value of 0.01. The mean percentage difference between the plasma and serum pyruvate of the patient group was 51% and that of the control group was 60% both of which are above the within individual biological variation (15.2%) as well as the reference change value (RCV) or critical difference for pyruvate (47%). The recovery percentage of the pyruvate on plasma was below the acceptable range (80-120%).
Conclusion: There was a significant under-estimation of pyruvate in plasma compared to serum samples in both the patient and control groups and the mean percentage difference is beyond the within subject biological variation of pyruvate for clinical use. Thus the use of NaF plasma for pyruvate determination is not recommended.

Peer reviewed CASE STUDY
Open Access

Patient mix-up due to pre-labelling of specimen tubes prior to sample collection
EM Morrison | HD Potgieter | JT Naicker
Published online: December 2018

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The Universitas Hospital NHLS Laboratory received a query from a paediatrician regarding the “delayed” laboratory results for baby H, a 1-month-old infant. The laboratory had received nine specimens from that same unit but none for baby H.
Upon investigation, using standard laboratory procedures of checking traceability and delta-checking of consecutive chemistry test results over a few days, results were found for a baby whose blood had not been sampled that day (baby M). Review of baby M’s results appeared to better match the clinical findings of baby H mainly because he was jaundiced (on phototherapy) and baby H was not.
A further complication was that 10 sample collection tubes had been pre-labelled in preparation for the phlebotomy procedure. However, because blood had not been collected from baby M there was the added possibility of a serial error in sample-patient linking in 8 of the remaining 9 samples.
Most laboratory errors occur in the pre-analytical phase, and many of these involve mislabelling of specimen tubes. Morning group pre-labelling is a common Universitas hospital practice prior to actual phlebotomy and is designed to speed up the sample collection process, so that results are available in time for the morning consultant ward round. This report serves to act as an alert of the possible dangers of serial error and possible disastrous effect on patient care.


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