Papers by YAHAYA MUHAMMAD USMAN
International Journal of Mycobacteriology
Background: Pulmonary mycosis (PM) poses a great diagnostic challenge due to the lack of pathogno... more Background: Pulmonary mycosis (PM) poses a great diagnostic challenge due to the lack of pathognomonic and radiological features, especially in the absence of mycology laboratory tests. This study was aimed to isolate, phenotypically identify, determine the prevalence of pulmonary fungal pathogens and antifungal susceptibility pattern of isolates of presumptive tuberculosis (PTB) patients attending Federal Teaching Hospital (FTH) Gombe, Nigeria. Methods: After ethical approval, three consecutive early morning sputa were collected from 216 participants with presumptive of PTB attending FTH Gombe, between May 2, 2017 and May 30, 2018. Samples were processed using standard mycological staining, microscopy, sugar biochemistry, and antifungal susceptibility test protocols. Sociodemographic variables and risk factors of pulmonary fungal infection were assessed through structured questionnaires. Pulmonary fungal infection was defined by the positive culture in at least two sputa. PTB was defined by Genexpert® nested polymerase chain reaction. Results: Of the 216 participants, 19.9% had PTB and 73.6% had pulmonary fungal pathogens. Among the isolated pulmonary fungal pathogens, Aspergillus fumigatus made the highest occurrence, while 6.5% had PTB-fungal co-infection. No significant association existed between the prevalence of PM with age and sex of participants (P < 0.05). Cigarette smoking (adjusted odds ratio [aOR] = 15.9 [95% confidence interval (CI): 0.9–268.8]), prolong antibiotic use (aOR = 77.9 [95% CI: 4.7–1283]) and possession of domestic pet (aOR = 77.9 [95% CI: 4.7–1283]) were significant risk factors of PM (P < 0.05). Penicillium citrinum, Mucor spp. and Aspergillus flavus are more susceptible to voriconazole, and Candida albicans was found to be more susceptible to Nystatin. Of the 159 fungal isolates, 92.5% were resistant to fluconazole. Conclusion: Findings from this study revealed high level pulmonary fungal pathogens, especially among PTB patients. A majority of fungal isolates were resistant to fluconazole. It's recommended that persons should do away with or minimize risk factors for pulmonary fungal pathogens identified in this study.
International Journal of Mycobacteriology
Background: This cross-sectional study evaluated Apoptotic Protease Activating Factor and cluster... more Background: This cross-sectional study evaluated Apoptotic Protease Activating Factor and cluster of differentiation-4+ (CD4+) T-cell counts in patients infected with Mycobacterium tuberculosis in Bauchi, Nigeria. Methods: This involved 180 blood samples from 90 tuberculosis (TB)-infected patients and 90 of their close contacts at home or attending Federal Medical Center Azare and Infectious Disease Hospital Bayara, Bauchi, Nigeria. The blood samples were analyzed for Apoptotic Protease Activating Factor (Apaf-1) expression using ELISA and CD4+ T cells using cyflow counter. Structured questionnaires were also used to collect the sociodemographic and clinical data of the study participants. Results: Eighty-six of the TB-infected patients had pulmonary TB (PTB), two had spine TB, and two had pleural TB. No statistically significant difference was recorded in CD4+ T-cell counts (P = 0.2935) between participants with PTB (mean ± standard deviation [SD]: 680.4 ± 235 cells/mm3) and those with extra-PTB (mean ± SD: 553.0 ± 130.5 cells/mm3). Similarly, there was no significant difference in Apaf-1 concentration (P = 0.1432) between participants with PTB (mean ± standard error of the mean [SEM]: 320.3 ± 35.4 pg/ml), and participants with extra-PTB (mean ± SEM: 143.7 ± 7.8 pg/ml). No significant difference was recorded in CD4+ T-cell counts (P = 0.4299) between the participants on treatment (mean ± SD: 758.6 ± 358.6 cells/mm3) and those who are treatment naïve (mean ± SD: 637.7 ± 208.4 cells/mm3). Similarly, there was no significant difference in Apaf-1 concentration (P = 0.6829) between the study participants on treatment (mean ± SEM: 336.3 ± 34.7 pg/ml) and those who are not on treatment (mean ± SEM: 381.2 ± 176.8 pg/ml). The CD4+ T-cells count was significantly higher in the controls (866.7 ± 288.4 cells/mm3) compared to the TB (675.0 ± 232.7 cells/mm3) patients (P < 0.0001). However, there was no significant difference in Apaf-1 expression between the control (312.4 ± 34.6 pg/ml) and the TB patients (329.1 ± 44.0 pg/ml) (P = 0.7658). Conclusion: Findings from this study showed a lower T-cell immune function during TB infection. However, Apaf-1 has no relevance on TB progression and control.
Nigerian Postgraduate Medical Journal
Background: Diabetic foot ulcers (DFUs) present with high morbidity and reduce patient's qual... more Background: Diabetic foot ulcers (DFUs) present with high morbidity and reduce patient's quality of life. There is a gross paucity of data on biofilm-producing bacteria in DFU Infection in North-Western Nigeria. The study sought to determine the biofilm-forming ability of bacteria isolates from DFUs and determine their antimicrobial susceptibility pattern in Zaria, North-Western Nigeria. Materials and Methods: This hospital-based cross-sectional study of patients with DFUs was conducted from June 2018 to February 2020. Consecutive biopsies were aseptically collected. Bacteria were isolated and identified using a Microgen kit. Biofilm forming ability and antibiogram of isolates were determined using microtitre plate and disk diffusion methods, respectively. Results: Of the 225 participants enrolled, males constituted the majority, 144 (64.0%) with 88 (36.0%) females, the median age of participants was 54 (48–60) years, and the age range was 36–77 years. A total of 172 bacteria were isolated, and 123 (71.5%) were biofilm producers. Staphylococcus aureus (26.7%) was the highest biofilm producer, while Citrobacter freundii and Stenotrophomonas maltophilia were the least biofilm producers, 1 (0.6%) each. A disproportionate resistance pattern was demonstrated among the biofilm and non-biofilm producers against the cephalosporins tested, ceftazidime (68% vs. 18%), ceftriaxone (50% vs. 8.0%) and cefotaxime (21% vs. 0.0%). About 46% and 68% of the biofilm producers were resistant to gentamycin and ciprofloxacin, respectively. While only 2% of the non-biofilm producers were resistant to imipenem, 11% of the biofilm producers were resistant to it. Conclusion: These findings revealed a high proportion of biofilm-producing bacteria and were more resistant than non-biofilm producers.
Annals of African Medicine, Oct 8, 2022
Background:Rotavirus infection is a significant cause of gastroenteritis in developing countries ... more Background:Rotavirus infection is a significant cause of gastroenteritis in developing countries and, in severe cases even leads to death. The impact of rotavirus vaccine introduction in reducing the rotavirus disease burden in children was well known. The study was aimed to determine the prevalence and clinical characteristics of rotavirus gastroenteritis before the introduction of rotavirus vaccine into Nigeria's routine immunization program.Materials and Methods:We conducted a cross-sectional hospital-based study involving 735 children aged 0–59 months with acute gastroenteritis hospitalized at the Ahmadu Bello University Teaching Hospital Zaria from September 2017 to August 2020. Relevant sociodemographic and clinical data were obtained and entered into the World Health Organization standardized case investigation forms. Stool specimens were tested for rotavirus Group A antigen using the ProSpecT™ Rotavirus Microplate Assay by Thermoscientific Oxoid Microbiology UK.Results:One hundred and fifty-three stool samples tested positive for rotavirus giving a prevalence of 20.8%. One hundred and two (66.7%) children with rotavirus gastroenteritis were infants. There were 87 males and 66 females with M: F ratio of 1.3:1. Only 30 (19.6%) children with rotavirus-associated diarrhea presented with severe dehydration. The presence of vomiting was significantly associated with rotavirus diarrhea (P = 0.001). More cases of rotavirus diarrhea occurred in September through February. None of the studied children were vaccinated against rotavirus.Conclusion:The prevalence of rotavirus diarrhea remains high in this study. Infants were recognized as a high-risk group, and none of them were vaccinated against rotavirus and this underscores the urgent need for implementing the rotavirus vaccine in the national vaccination program to reduce the disease burden in the country.
Infection & Chemotherapy
Backround: Data on Dengue virus (DENV) infection prevalence, geographic distribution and risk fac... more Backround: Data on Dengue virus (DENV) infection prevalence, geographic distribution and risk factors are necessary to direct appropriate utilization of existing and emerging control strategies. This study aimed to determine the pooled prevalence, risk factors of DENV infection and the circulating serotypes within Nigeria from January 1, 2009 to December 31, 2020. Materials and methods: Twenty-one studies out of 2,215 available articles were eligible and included for this systematic review. Relevant articles were searched, screened and included in this study according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria. The risk of bias in primary studies was assessed by Cochrane's method. Heterogeneity of pooled prevalence was calculated using the chi-square test on Cochrane's Q statistic, which was quantified by I-square values. The random-effects analyses of proportions were used to determine the pooled prevalence of DENV antibodies, antigen and RNA from eligible studies. Results: Of these, 3 studies reported co-circulation of all the 4 serotypes, while 2 separately reported co-circulation of DENV-1 &2 and DENV-1 to-3. All the antibody-based studies had significantly high heterogeneity (I 2 >90%, P <0.05), while the NS1 and PCR-based studies had low heterogeneity (I 2 <25%, P >0.05). The pooled prevalence of DENV IgM, IgG, RNA, NS1 and neutralizing antibodies were 16.8%, 34.7%, 7.7%, 7.7% and 0.7%, respectively. Southeast Nigeria had the highest pooled DENV-IgG seropositivity, 77.1%. Marital status, gender,
Sokoto Journal of Medical Laboratory Science, 2021
Malaria is the most dominant cause of human morbidity and mortality with huge medical, psychologi... more Malaria is the most dominant cause of human morbidity and mortality with huge medical, psychological and economic impact in Nigeria. Prompt and accurate diagnosis is one of the key components in the control of malaria disease. In Katsina State, clinical (symptomatic) diagnosis and Pf HRP-2 RDT are the two main methods routinely used for the diagnosis of malaria. Only tertiary, secondary and few primary hospitals employ microscopy in malaria diagnosis. This study was done to assess the performance of the clinical diagnosis, SD-BioLine (PfHRP-2) rapid diagnostic tests (RDTs) and Microscopy in the diagnosis of Malaria disease in Katsina State. In this cross-sectional study, involving three hospitals, blood samples of 400 clinically suspected malaria patients were tested for malaria using microscopy with Giemsa-stained films and Rapid Diagnostic Test (RDT), using SD Bioline Pf HRP-2 kit. Malaria prevalence using microscopy was 29.8% (119/400). Pf HRP-2 RDT recorded lower sensitivity wit...
Background: Epstein-Barr virus (EBV) is a gamma herpes virus that infects 95% of the human popula... more Background: Epstein-Barr virus (EBV) is a gamma herpes virus that infects 95% of the human population. Primary infection is often asymptomatic but results in lifelong infection, when immune is compromised EBV is associated with lymph proliferative diseases and malignancies such as Burkitt´s lymphoma, Nasopharyngeal Carcinoma, and Hodgkin's lymphoma. This study was designed to determine the prevalence of EBV in Human immune-deficient virus (HIV)-infected individuals in Katsina State, Nigeria. Materials and Methods: Two hundred and seventy-three (273) consented HIV-infected individuals were screened for EBV antigens, for the period of five months (November 2018-March 2019). The sera of individuals were subjected to antigen serological assay by enzyme-linked immunosorbent assay. Results: Out of 273 subjects that were tested 89(32.6%) were EBV antigen positive and 184(67.4%) were EBV antigen negative, prevalence of EBV antigen was higher in females with 61(22.3%), age group 35-44 years 30(10%), CD4+ 425-524 cells/µl 20(7.4%), and viral load 48(18.6%) with less than 1000 count. Conclusion: This study has contributed baseline data and provided insights in EBV-HIV co-infection in Katsina Northwestern Nigeria This would undoubtedly serve as a basis for further studies on EBV in the general population.
This study highlights the increasing interest in identifying the parameters adequate to measure r... more This study highlights the increasing interest in identifying the parameters adequate to measure rainfall and wet day’s variations as the determinant of malaria occurrences and distribution for a period of twelve months (2012) in the Federal Capital Territory. Satellite data were developed to identify malaria risk area and to evaluate amounts of rainfall and the durations of wet or rainy days conducive to malaria outbreaks at appropriate scales. Secondly, the studies examine the correlation of monthly and annual malaria cases, and rainfall amounts, including wet days with a lag time of one year. The result of correlation analysis shows that relationship exists between the observed weather variables and malaria. The coefficients of determination R2 of rainfall influencing malaria is 0.3109 (31.1%) and wet days influencing malaria is 0.3920 (39.2%). These results indicate that the rainfall amounts positively correlate with malaria cases with prediction estimate by 78.47 % and 88.68% re...
Annals of Tropical Pathology, 2021
The emergence of coronavirus disease 2019 (COVID-19) has caused global health concerns in the var... more The emergence of coronavirus disease 2019 (COVID-19) has caused global health concerns in the various strata of health-care authorities. The detection of the etiologic agent, SARS-CoV-2 became essential for case identification and prevention of transmission. In this review, literature was retrieved and sifted from different search engines. We highlighted some mainstream pointers vis-à -vis preanalytical, analytical, and postanalytical phases of laboratory detection of SARS-CoV-2 using real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. The quantitative RT-PCR is considered as the gold standard for establishing the diagnosis of COVID-19. However, laboratories must pay attention to all the testing phases from sample collection to final release of results in order to avoid false-negative or false-positive results. It is also necessary to understand possible challenges and conduct risk assessment before the commencement of testing in the designated laboratory.
Journal of Clinical Sciences, 2021
Antimicrobial resistance (AMR) is a major global health challenge, especially in low- and middle-... more Antimicrobial resistance (AMR) is a major global health challenge, especially in low- and middle-income countries (LMIC). Programs that appropriate antibiotic use such as antimicrobial stewardship, is a global health strategy adopted by the World Health Organization to contain threats posed by AMR. Unfortunately, many LMICs are at best left behind in the process of developing antimicrobial stewardship programs (ASP). We highlighted the roles of the clinical microbiology laboratory in antimicrobial stewardship and challenges associated with the program in LMICs. We further suggested ways forward in the adoption and implementation of existing programs in resource-limited settings. There is generally nonexistent or at best, fewer ASP in the LMICs. More efforts need to be channeled toward fighting the AMR scourge, primarily by adopting ASP while utilizing the little resources available.
Human Viruses: Diseases, Treatments and Vaccines, 2021
International Health, 2021
As the coronavirus disease 2019 (COVID-19) pandemic continues to rise and second waves are report... more As the coronavirus disease 2019 (COVID-19) pandemic continues to rise and second waves are reported in some countries, serological test kits and strips are being considered to scale up an adequate laboratory response. This study provides an update on the kinetics of humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and performance characteristics of serological protocols (lateral flow assay [LFA], chemiluminescence immunoassay [CLIA] and ELISA) used for evaluations of recent and past SARS-CoV-2 infection. A thorough and comprehensive review of suitable and eligible full-text articles was performed on PubMed, Scopus, Web of Science, Wordometer and medRxiv from 10 January to 16 July 2020. These articles were searched using the Medical Subject Headings terms ‘COVID-19’, ‘Serological assay’, ‘Laboratory Diagnosis’, ‘Performance characteristics’, ‘POCT’, ‘LFA’, ‘CLIA’, ‘ELISA’ and ‘SARS-CoV-2’. Data from original research articles on SARS-C...
International Journal of Medical Laboratory, 2019
Background and Aims: Uropathogenic Escherichia coli (UPEC) are considered major reservoir for gen... more Background and Aims: Uropathogenic Escherichia coli (UPEC) are considered major reservoir for genes encoding antimicrobial resistance. The mechanism of resistance and persistence of UPEC has been attributed to the production of biofilm and Extended Beta Lactamase (ESBL). This hospital-based prospective study determined how biofilm and ESBL production facilitate antibacterial resistance amongst UPEC isolated from catheter urine of patients attending the University of Ilorin Teaching Hospital, Nigeria. Materials and Methods: Urine samples from 113 catheterized inpatients and outpatients were analysed. Female subjects accounted for 47 (41.6%) of the study population. Standard microbiological methods and Analytical Profile Index (API) 20E were used for the isolation and identification of UPEC. Tissue culture plate technique was used to demonstrate biofilm production potentials and double-disc synergy test was used to determine ESBL production. Results: Catheter associated urinary tract...
Afro-Egyptian Journal of Infectious and Endemic Diseases, 2019
Background and study aim: Urinary tract infection (UTI) is among the most common complications of... more Background and study aim: Urinary tract infection (UTI) is among the most common complications of catheterized persons in hospital settings especially, those caused by extended spectrum beta lactamase (ESBL) and biofilm producing Escherichia coli.This hospital based, cross sectional study was carried out to determine the prevalence and associated factors associated with Uropathogenic Escherichia coli (UPEC) isolates from catheterized persons (inpatients and outpatients) attending Ilorin Tertiary hospital, Nigeria Materials and Methods: Between 2 nd April and 30 th June 2016, urine samples from 113 catheterized inpatient and outpatients were evaluated. Female subjects accounted for 47(41.6%) of the study population. Standard microbiological methods and Analytical Profile Index (API) 20E system were used for the isolation and identification of UPEC, respectively. Tissue culture plate (TCP) technique was used to demonstrate biofilm production potentials. Results: The prevalence of catheter associated urinary tract infection (CA-UTI) in this study was 70.8% most of which are Gram negative bacilli belonging to the Enterobacteriaceae family with Escherichia coli 44(55.0%) being the most predominant pathogen. Extended spectrum beta lactamase (ESBL) E coli in this study was 27.2% of which all (100%) were strong biofilm producers. Female subjects had relatively higher prevalence of UPEC isolates, 29 (65.9%) than the male counterparts. Whereas, the highest cases of UPEC was in 61-70 years age group, 29.5%. There was significant association between UPEC and age and gender of subjects (p<0.05). Conclusion: Findings from this study shows that E. coli is still the most common uropathogenic bacteria isolate in catheterized persons. Biofilm production confers some degree of ESBL production and antibiotic resistance.
Al-Azhar Assiut Medical Journal, 2016
Background There are several malaria preventive measures. The availability of a particular method... more Background There are several malaria preventive measures. The availability of a particular method does not guarantee its adherence and effective usage. This eventually may not provide the desired results for the fight against malaria. Pregnant women are at higher risk of contracting malaria, and therefore it is necessary that they should be protected against the infection. Objective of the study This cross-sectional study investigated the significant roles of various preventive measures against malaria infection among pregnant women attending four selected secondary health facilities in Kaduna state, Nigeria. Materials and methods Blood samples were collected from 353 pregnant women attending selected hospitals. Malaria parasite microscopy was conducted on the basis of standard protocols. Structured questionnaires were used to obtain data with regard to subject knowledge and practice of preventive measures against malaria. Results Out of the 353 subjects tested, 79 (22.4%) had malaria parasitaemia. One hundred and fifteen (32.6%) subjects used no preventive measure, 45 (12.7%) used sulfadoxine-pyrimethamine prophylaxis, 53 (15.0%) used insecticide treated nets (ITNs), 72 (20.4%) used indoor insecticide house spray, while 68 (19.3%) used > 1 preventive measures. Out of the 79 subjects infected with malaria, 57 (72.2%) do not know how to prevent malaria, while 22 (27.8%) had prior knowledge of malaria prevention. Highest cases (41 [51.9%]) of malaria parasitaemia were recorded in women with no knowledge of preventive measures during pregnancy, while women who used > 1 measures have the least cases (5 [6.3%]) of malaria parasitaemia. There was statistical association between the use of preventive measures and decreased malaria parasitaemia (P < 0.0001). Conclusion Findings from this study revealed that there is need for more sensitization campaigns on available malaria preventive measures. Also, the combination of preventive methods should be considered by pregnant women in order to minimize their chances of acquiring malaria.
Bangladesh Medical Journal Khulna, 2016
Stroke is the leading cause of adult disability and is the third commonest cause of death worldwi... more Stroke is the leading cause of adult disability and is the third commonest cause of death worldwide. It is a major cause of morbidity and mortality with disability and social dependence throughout the world. An observational, descriptive, cross-sectional study was conducted among purposively selected one hundred and seventy patients with stroke admitted at Kushtia Medical College Hospital, Kushtia from July 2014 to June 2015 to evaluate the different modifiable risk factors and their frequency among stroke patients. Stroke patients with more than 24 hours duration presenting within seven days of onset irrespective of age, sex and demographic profile were included in the study. After obtaining informed consent, patients who fulfilled the inclusion criteria were thoroughly evaluated for the presence of risk factors. Data were collected by investigators themselves. Out of 170 confirmed cases of stroke, 89 (52.35%) were male, while 81 (47.65%) were female. Mean age of the patients was 63.74 years with a standard deviation of 16.5 years. The highest incidence 43 (24.70%) of stroke was in the age group of 60 to 69 years. As many as 122 (71.76%) had ischaemic stroke, while 48 (28.24%) had haemorrhagic stroke. At least 119 (70.00%) cases were hypertensive. 41 (24.11%) cases had diabetes mellitus, 31 (18.23%) had hyperlipidaemia, 52 (30.6%) were smokers and 25 (14.70%) had past history of stroke. Among 81 female patients, 66 (81.48%) were in post-menopausal, whereas 15 (18.52%) were in the reproductive age group. Of them 5 (33.33%) had history of taking oral hormonal contraceptive. Hypertension, smoking, diabetes mellitus and hyperlipidaemia are the identified modifiable risk factors associated with stroke.
Research Journal of Microbiology, 2015
Cytomegalovirus (CMV) screening in pregnancy has not been recommended during antenatal clinic day... more Cytomegalovirus (CMV) screening in pregnancy has not been recommended during antenatal clinic days in Nigeria and most countries of the world. However, CMV has been widely accepted as, the viral etiology with the greatest propensity for congenital transmission. Due to CMV ubiquity, seronegative women are highly susceptible to CMV infection and thus, has increased risk of maternal infections and possibly congenital transmission. In view of this, this study aimed to determine the seroprevalence of women, who are anti-CMV IgG seronegative, thus susceptible to CMV infections. We made use of Novalisa TM anti-CMV IgG ELISA kit to screen 182 blood samples of pregnant women attending antenatal clinics of University of Maiduguri Teaching Hospital (UMTH), Maiduguri, Nigeria. Structured questionnaire was used to collect participants' sociodemographic data. A total of 38 out of 182 subjects were anti-CMV IgG seronegative making a seroprevalence of 20.9%. There was significant statistical association between seronegativity and subjects' education level and history of previous blood transfusion (p<0.05) but not with age, parity, gravida and gestation age (p>0.05). Findings from our evaluation indicated that many pregnant women were anti-CMV IgG seronegative and thus susceptible to maternal CMV infections. These women have high risk of contacting primary CMV infections and might eventually pose danger to their unborn fetuses in the absence of appropriate preventive measures.
Sub-Saharan African Journal of Medicine, 2014
Clinical microbiology laboratory plays several important roles in the management of bacterial inf... more Clinical microbiology laboratory plays several important roles in the management of bacterial infections. Isolation, identification of pathogenic microorganisms in cultures and subsequent antimicrobial susceptibility testing always assists in selecting appropriate antimicrobial agent and prevention of unnecessary complications. The most important and primary test to perform directly on some special samples such as cerebrospinal fluid and positive cultures is Gram staining which serves as the most rapid and simplest test to characterize microorganisms. It is therefore highly likely that the information provided by the Gram staining will help to assess the adequacy of preliminary diagnosis and antimicrobial therapy selected after collecting culture specimens and before final identification of the microorganism. In recent reports, the impact of Gram staining results on patient mortality has been documented. On the other hand, there remains the possibility that Gram staining results do not match with the final identification of microorganisms. This would carry a risk leading to inadequate antimicrobial therapy and potentially affecting patients' clinical course and mortality. The aim of this mini review is to analyze and discuss the clinical significance and limitations of reporting Gram staining results for sample meant for bacteriological investigations.
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Papers by YAHAYA MUHAMMAD USMAN