African Journal of Laboratory Medicine最新文献

Background: Urinary tract infections are common bacterial infections affecting millions worldwide. Although treatment options for urinary tract infections are well established, with ciprofloxacin long considered one of the antibiotics of choice, increasing antibiotic resistance may delay the initiation of appropriate therapy. While this increase in antimicrobial resistance has been demonstrated in multiple studies around the world, there is a dearth of information from developing countries.

Objective: This study aimed to describe the antimicrobial susceptibility patterns of commonly isolated bacterial uropathogens in a South African hospital.

Methods: Antimicrobial susceptibility data of isolates obtained from urine specimens at the RK Khan Hospital, a regional hospital in KwaZulu-Natal, South Africa, between January 2018 and December 2020 were retrieved from the hospital's laboratory information system and analysed to determine the differences in resistance rates between the most frequently isolated bacterial uropathogens.

Results: Of the 3048 bacterial urinary pathogens isolated between 2018 and 2020, Escherichia coli (1603; 53%) was the most common, followed by Klebsiella spp. (437; 14%). Both E. coli and Klebsiella spp. showed high rates of resistance to amoxicillin/clavulanic acid (29.8% and 42.3%) and ciprofloxacin (37.7% and 30.4%). Nitrofurantoin resistance was low among E. coli (6.2%) but high among Klebsiella spp. (61.3%).

Conclusion: E. coli and Klebsiella spp. in this study were highly resistant to amoxicillin/clavulanic acid and ciprofloxacin, two of the frequently prescribed oral treatment options.

What this study adds: This study highlights the importance of regular local antimicrobial resistance surveillance to inform appropriate empiric therapy.

Background: Rifampicin resistance missed by commercial rapid molecular assays but detected by phenotypic assays may lead to discordant susceptibility results and affect patient management.

Objective: This study was conducted to evaluate the causes of rifampicin resistance missed by the GenoType MTBDRplus and its impact on the programmatic management of tuberculosis in KwaZulu-Natal, South Africa.

Methods: We analysed routine tuberculosis programme data from January 2014 to December 2014 on isolates showing rifampicin susceptibility on the GenoType MTBDRplus assay but resistance on the phenotypic agar proportion method. Whole-genome sequencing was performed on a subset of these isolates.

Results: Out of 505 patients with isoniazid mono-resistant tuberculosis on the MTBDRplus, 145 (28.7%) isolates showed both isoniazid and rifampicin resistance on the phenotypic assay. The mean time from MTBDRplus results to initiation of drug-resistant tuberculosis therapy was 93.7 days. 65.7% of the patients had received previous tuberculosis treatment. The most common mutations detected in the 36 sequenced isolates were I491F (16; 44.4%) and L452P (12; 33.3%). Among the 36 isolates, resistance to other anti-tuberculosis drugs was 69.4% for pyrazinamide, 83.3% for ethambutol, 69.4% for streptomycin, and 50% for ethionamide.

Conclusion: Missed rifampicin resistance was mostly due to the I491F mutation located outside the MTBDRplus detection area and the L452P mutation, which was not included in the initial version 2 of the MTBDRplus. This led to substantial delays in the initiation of appropriate therapy. The previous tuberculosis treatment history and the high level of resistance to other anti-tuberculosis drugs suggest an accumulation of resistance.

Background: Haemolysis - one of the major limiting factors of red cell concentrate quality - must be measured as a quality-monitoring requirement. According to international quality standards, percentage haemolysis must be monitored in 1.0% of red cell concentrates produced monthly and maintained under 0.8%.

Objective: This study assessed three alternative methods for determining plasma haemoglobin concentration in peripheral blood banks that lack a plasma or low haemoglobin photometer - the gold-standard method - in Sri Lanka.

Methods: A standard haemolysate was prepared using an unexpired whole blood pack of normal haemoglobin concentration. A concentration series from 0.1 g/dL to 1.0 g/dL was prepared by diluting portions of standard haemolysate with saline. The alternative methods, namely visual haemoglobin colour scale, spectrophotometric calibration graph, and standard haemolysate capillary tube comparison, were designed using this concentration series and were used to test red cell concentrates received at the Quality Control Department of the National Blood Center, Sri Lanka, from February 2021 to May 2021.

Results: A strong correlation was observed between the haemoglobin photometer method and the alternative methods (R = ~0.9). Based on the linear regression model, the standard haemolysate capillary tube comparison method was the best of the three alternative methods (R ² = 0.974).

Conclusion: All three alternative methods are recommended for use in peripheral blood banks. The standard haemolysate capillary tube comparison method was the best model.

[This corrects the article DOI: 10.4102/ajlm.v11i1.1803.].

Background: Research and clinical use of clinical pharmacology laboratories are limited in low- and middle-income countries. We describe our experience in building and sustaining laboratory capacity for clinical pharmacology at the Infectious Diseases Institute, Kampala, Uganda.

Intervention: Existing laboratory infrastructure was repurposed, and new equipment was acquired. Laboratory personnel were hired and trained to optimise, validate, and develop in-house methods for testing antiretroviral, anti-tuberculosis and other drugs, including 10 high-performance liquid chromatography methods and four mass spectrometry methods. We reviewed all research collaborations and projects for which samples were assayed in the laboratory from January 2006 to November 2020. We assessed laboratory staff mentorship from collaborative relationships and the contribution of research projects towards human resource development, assay development, and equipment and maintenance costs. We further assessed the quality of testing and use of the laboratory for research and clinical care.

Lessons learnt: Fourteen years post inception, the clinical pharmacology laboratory had contributed significantly to the overall research output at the institute by supporting 26 pharmacokinetic studies. The laboratory has actively participated in an international external quality assurance programme for the last four years. For clinical care, a therapeutic drug monitoring service is accessible to patients living with HIV at the Adult Infectious Diseases clinic in Kampala, Uganda.

Recommendations: Driven primarily by research projects, clinical pharmacology laboratory capacity was successfully established in Uganda, resulting in sustained research output and clinical support. Strategies implemented in building capacity for this laboratory may guide similar processes in other low- and middle-income countries.

Background: Integrated health systems with strong laboratory networks are critical in improving public health. The current study assessed the laboratory network in Ghana and its functionality using the Assessment Tool for Laboratory Services (ATLAS).

Intervention: A national-level laboratory network survey was conducted among stakeholders of the Ghanaian laboratory network in Accra. Face-to-face interviews were conducted from December 2019 to January 2020, with follow-up phone interviews between June and July 2020. Also, we reviewed supporting documents provided by stakeholders for supplementary information and transcribed these to identify themes. Where possible, we completed the Laboratory Network scorecard using data obtained from the ATLAS.

Lessons learnt: The Laboratory Network (LABNET) scorecard assessment was a valuable addition to the ATLAS survey as it quantified the functionality of the laboratory network and its overall advancement toward achieving International Health Regulations (2005) and Global Health Security Agenda targets. Two significant challenges indicated by respondents were laboratory financing and delayed implementation of the Ghana National Health Laboratory Policy.

Recommendations: Stakeholders recommended a review of the country's funding landscape, such as funding laboratory services from the country's internally generated funds. Also, they recommended laboratory policy implementation to ensure adequate laboratory workforce and standards.

Between April and May 2022, 10 healthy adult non-patients were recruited from Pusan National University Hospital. Venous blood drawn into a syringe was transferred into test tubes with a zero-to-45-minute delay. The transfer was done sequentially in two positions with the syringe and the needle adaptor end (1) heading downwards and (2) heading upwards. Haemoglobin levels gradually increased over time in position 1 transfer while they gradually decreased in position 2. Therefore, blood must be transferred quickly from a syringe to a tube for reliable test results.

What this study adds: Our findings confirm that delays between blood collection and transfer can affect haemoglobin levels.

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: Screening for hyperglycaemia in pregnancy (HIP) is an important component of comprehensive antenatal care. Screening practices for HIP in Nigeria and factors that influence these practices are not well understood.

Objective: We examined the screening practices for HIP and their correlates among antenatal healthcare providers (AHPs).

Methods: This descriptive cross-sectional study of AHPs providing all levels of antenatal care was conducted between August 2019 and September 2019 in Jos, Nigeria. Eligible AHPs completed a semi-structured, self-administered questionnaire, and data were analysed for adherence to recommended screening practices such as World Health Organization, International Association of Diabetes and Pregnancy Study Groups and National Institute for Health and Care Excellence guidelines.

Results: Of the 128 respondents included in the analysis, 59 (46.1%) were male and 69 (53.9%) were female. The mean participant age was 35.7 years (standard deviation: ± 8.5 years). Most (68.0%) screened all pregnant women (universal screening) for gestational diabetes mellitus. Fasting blood glucose (77.0%) and random blood glucose (55.7%) were the most common tests used. Only 27 respondents (22.1%) screened using the 75 g oral glucose tolerance test, and most were doctors, AHPs in faith-based or government institutions, tertiary institutions and facilities with availability of automated glucose analysers (p < 0.05 for all).

Conclusion: Screening practices for HIP among the AHPs do not generally conform to best practices. Hence, there is an urgent need for implementation of universal guidelines and provision of regular updates and basic glucose measuring devices for AHPs at all healthcare levels.