African Journal of Laboratory Medicine最新文献

Background: HIV and malaria interact at the level of the host's susceptibility to infection, but little is known about the effect of HIV on malaria infection in Nigeria.

Objective: This study estimated the prevalence of malaria parasitaemia and its relationship with HIV immunodeficiency.

Methods: This cross-sectional study was conducted in two hospitals in Abuja, Nigeria between October 2012 and March 2013 among 600 respondents, comprising 200 HIV-negative controls, 200 HIV-positive patients on antiretroviral therapy (ART), and 200 HIV-positive patients not on ART. Malaria parasites, malaria density and absolute CD4 counts were carried out on all three groups. Participants with CD4 counts below 350 cells/mm³ were considered immunocompromised and likely to develop opportunistic infections.

Results: Most study participants were aged 21-40 years (65.2%). The mean CD4 counts of HIV-positive patients not on ART (300 ± 211 cells/mm³) and those on ART (354 cells/mm³) were significantly lower than among controls (834 cells/mm³) (p < 0.001). Malaria prevalence was not statistically different between the controls (44.5%), patients on ART (40.5%), and those not on ART (39.5%) (p = 0.562). Compared to 7% immunodeficiency among controls, 56% of patients on ART and 65.5% of those not on ART had a CD4 count < 350 cells/mm³ (p < 0.001). The prevalence of malaria parasitaemia among immunodeficient individuals (42.4%) was similar to prevalence among those with CD4 counts > 350 cells/mm³ (40.8%; p = 0.695).

Conclusion: These findings suggest that malaria parasitaemia is not an opportunistic infection among HIV-positive individuals in Nigeria.

Background: Previous studies in Nigeria have reported the presence of hepatitis B virus (HBV) genotype E and the availability of immune escape mutants. There is a paucity of data on chronic patients on long-term antiviral therapy for HBV infection.

Objective: This study assessed HBV genotypes and drug resistance variants among patients with chronic HBV infection receiving tenofovir in Jos, Nigeria.

Methods: This cross-sectional study consecutively enrolled 101 patients (51 with HIV/HBV co-infection and 50 with HBV infection only) on antiviral therapy from February 2018 to May 2019 at four hospitals in Jos, Nigeria. DNA quantification of HBV was performed on all samples; 30 samples with detectable viral load were selected for genotyping using Sanger sequencing by targeting the full-length sequences of reverse transcriptase gene of the HBV genome. Phylogenetic analysis was performed with reference sequences from GenBank. Escape mutant and drug resistance analysis were performed using HBV drug resistance interpretation and Geno2pheno.

Results: Only 30 (29.7%) of the 101 study participants had detectable HBV DNA. Of these, six (20.0%) isolates were successfully amplified and sequenced. The identified genotype was E, including escape mutations L127R (16.7%) and G145A (16.7%).

Conclusion: This study revealed exclusive dominance of genotype E in Nigeria. The S gene mutations G145A and L271R are known to be associated with modified antigenicity and impaired serologic assays, which may cause false negatives in the detection of anti-HBV surface antigen. The presence of mutants that are associated with vaccine immune escape may also have diagnostic and vaccine immune response implications.

Background: The development of alternative control measures, such as phage therapy or adjunctive therapy, is urgently needed to manage the dissemination of carbapenemase-producing Klebsiella pneumoniae.

Objective: This study aimed to evaluate the therapeutic potential of formulated phage cocktails and their interaction with select antibiotics in inhibiting the growth of carbapenemase-producing K. pneumoniae clinical isolate in vitro in Kenya.

Methods: The study was conducted from February 2021 to October 2021 at the Institute of Primate Research, Nairobi, Kenya. Phage cocktails were formulated based on the morphology and biological properties of precipitated Klebsiella phages. The efficacy of individual bacteriophages and phage cocktails as well as their combination with antibiotics were determined for their inhibitory activity on carbapenemase-producing K. pneumoniae (KP20).

Results: The precipitated bacteriophages were members of Myoviridae, Siphoviridae and Podoviridae. Regarding the evaluation of the phage cocktails, the absorbances at 600 nm of the bacterial culture treated with the two-phage cocktail (2φ MA) ranged from 0.173 to 0.246 at 16 h and 20 h whereas it peaked from 2.116 to 2.190 for the positive control. Moreover, the results of the adjunctive therapy showed that the optical density at 600 nm of the bacterial culture treated with 2φ MA was 0.186 at 24 h post-incubation time while it was 0.099 with the bacterial culture treated with imipenem in combination with 2φ MA.

Conclusion: This study demonstrated that the two-phage cocktail in combination with imipenem was able to synergistically delay the increase in carbapenemase-producing K. pneumoniae growth in vitro.

Background: Globally, women living with HIV have a higher risk of vulvar neoplasia than HIV-negative women. Vulvar neoplasia among women living with HIV has not previously been characterised in Zambia.

Objective: This study determined the clinical and pathologic features of vulvar neoplasia among women living with HIV at the University Teaching Hospital, Lusaka, Zambia.

Methods: We conducted a cross-sectional study of vulvar lesions among 53 women living with HIV who presented with vulvar lesions between July 2017 and February 2018. The study assessed clinical and histological characteristics and prevalence of high-risk human papillomavirus (HRHPV).

Results: Twenty-one patients were diagnosed with vulvar squamous cell carcinoma (VSCC), 20 with usual vulvar intraepithelial neoplasm (uVIN), and the rest with either benign lesions or non-neoplastic lesions (NNL). Participants' mean age was 40 years. Patients with VSCC were significantly older than those with NNL (mean (s.d.): 43 (21) vs 33 (10), p = 0.004). The prevalence of HRHPV was 88.9% in VSCC patients and 100.0% in high-grade squamous intraepithelial lesion patients. HPV16 was the most common (52.6%) genotype. The clinical features of neoplasia were similar to those of NNL.

Conclusion: VSCC was significantly more common among women aged ≥ 40 years. HRHPV in VSCC and high-grade squamous intraepithelial lesions was high. Women with vulvar lesions, especially those aged > 40 years, should be evaluated for vulvar cancer. Young girls should be vaccinated to prevent vulvar cancer.

Background: Haemoglobinopathies are inherited haemoglobin disorders that result in anaemia characterised by erythrocyte anisopoikilocytosis. Red cell distribution width (RDW) measures anisopoikiloytosis and is readily reported by haematology analysers as a complete blood count parameter. The utility of RDW as a diagnostic marker of haemoglobinopathies in Kenya remains undetermined and undocumented.

Objective: This study aimed to determine the diagnostic efficacy of RDW in discriminating haemoglobinopathy and haemoglobinopathy-free cases in Kenya.

Methods: The case-control study used randomly selected haematology analyser outputs for haemoglobinopathy-free (241, 49.4%) and haemoglobinopathy cases (247, 50.1%) aged 1 month to 66 years old tested in the Aga Khan Hospital, Kisumu, and its satellite centres in western Kenya from 01 January 2015 to 31 December 2020. Results were verified using high performance liquid chromatography. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic power of RDW as a biomarker for sickle cell disease (SCD) and sickle cell trait phenotypes and β-thalassaemia.

Results: The RDW showed diagnostic significance in SCD phenotypes at 21.1 ROC curve coordinate with 67.7% sensitivity, 90.0% specificity, 0.789 accuracy, 70.5% positive predictive validity, 88.8% negative predictive validity, 6.77 positive likelihood ratio, 0.36 negative likelihood ratio and 18.94 (11.4-31.4) odds ratio.

Conclusion: An RDW of 21.1% is potentially a predictor of SCD haemoglobin phenotypes and should be included in the haematology screening algorithm as a critical value, above which suspected cases qualify to be investigated for SCD.

Background: Laboratories use quality control processes to monitor and evaluate analytical performance in terms of precision and bias. Sigma metrics provide an objective assessment of laboratory quality using the total allowable error as an additional parameter.

Objective: This study aimed to determine the sigma metrics of analytes when using different total allowable error guidelines.

Methods: A retrospective analysis was performed on 19 general chemistry analytes at Charlotte Maxeke Johannesburg Academic Hospital in South Africa between January 2017 and December 2017. Sigma metrics were calculated on two identical analysers, using internal quality control data and total allowable error guidelines from the Ricos biological variation database and three alternative sources (the Royal College of Pathologists of Australasia, the Clinical Laboratory Improvements Amendment, and the European Federation of Clinical Chemistry and Laboratory Medicine).

Results: The sigma performance was similar on both analysers but varied based on the guideline used, with the Clinical Laboratory Improvements Amendment guidelines resulting in the best sigma metrics (53% of analytes on one analyser and 46% on the other had acceptable sigma metrics) and the Royal College of Pathologists of Australia guidelines being the most stringent (21% and 23%). Sodium and chloride performed poorly across all guidelines (sigma < 3). There were also month-to-month variations that may result in acceptable sigma despite poor performance during certain months.

Conclusion: The sigma varies greatly depending on the total allowable error, but could be a valuable tool to save time and decrease costs in high-volume laboratories. Sigma metrics calculations need to be standardised.