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Review Article
ARTICLE IN PRESS
doi:
10.25259/JQUS_8_2026

Development of Diagnostic Criteria for Early Diagnosis of Gram-Positive and Gram-Negative Bacterial Sepsis: A Review

, ,
1Department of Medical Laboratory Sciences, Al-istiqama University Sumaila, Along Kano Road, Sumaila, Kano, Nigeria
2Department of Medical Microbiology and Parasitology, Bayero University Kano, Kano, Nigeria
3Department of Community Medicine, Bayero University Kano, Kano, Nigeria

* Corresponding author: Dr. Sunusi Usman Maaji, PhD, Department of Medical Laboratory Sciences, Al-istiqama University Sumaila, Along Kano Road, Sumaila, Kano, 700023, Nigeria. sunusimaaji@gmail.com

Received: , Accepted: ,
© 2026 Journal of Qassim University for Science - Published by Scientific Scholar
Licence
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

How to cite this article: Maaji SU, Akande AO, Abbas MA. Development of Diagnostic Criteria for Early Diagnosis of Gram-Positive and Gram-Negative Bacterial Sepsis: A Review. J Qassim Univ Sci. doi: 10.25259/JQUS_8_2026

Abstract

Bacterial sepsis remains a major driver of morbidity and significant mortality in developing regions, with sub-Saharan Africa, particularly Nigeria, bearing a disproportionate burden. Timely and accurate diagnosis of sepsis, coupled with precise differentiation between Gram-positive and Gram-negative etiologies, is critical for guiding appropriate antimicrobial therapy and improving prognosis. This review synthesizes the current landscape of sepsis diagnostics in Kano, Nigeria, examining the epidemiological context, utility, and limitations of existing diagnostic criteria. It also evaluates the potential of emerging technologies to address the unique challenges confronting prompt and accurate sepsis diagnosis in this resource-limited setting. We explored local bacterial profiles, the prevalence of antimicrobial resistance, and the practical application of clinical scoring systems and biomarkers. The review concludes by outlining a forward-looking strategy for developing and implementing more effective, accessible, and contextually appropriate diagnostic frameworks for sepsis in Kano and similar environments.

Keywords

Bacteria sepsis
Biomarkers
Diagnostic criteria
Morbidity
Mortality

INTRODUCTION

Bacterial sepsis, a life-threatening organ dysfunction caused by dysregulated host response to infection by bacterial agents, represents a formidable public health challenge globally.[1,2] In sub-Saharan Africa, the burden is particularly severe, exacerbated by factors such as high rates of infectious diseases (e.g., HIV and tuberculosis), limited healthcare infrastructure, and widespread antimicrobial resistance (AMR).[3-5] Kano, a major metropolitan and commercial hub in northern Nigeria, exemplifies the complex interplay of these challenges. Neonatal and paediatric sepsis are particularly significant contributors to mortality, with case fatality rates in the Kano environment reported at approximately 10.7%, and even higher among infants under one year of age.[3,6-8]

Early identification of bacterial sepsis and prompt initiation of appropriate antibiotic treatment are the cornerstones of effective management.[9] A critical step in this process is the differentiation between associated Gram-positive and Gram-negative bacterial pathogens, as this distinction fundamentally guides empirical antimicrobial selection. However, the diagnostic process in resource-constrained settings such as Kano is fraught with difficulties, including the limitations of traditional diagnostic methods and the inaccessibility of advanced technologies in the area. This review provides an analysis of the current state and the possible future development of diagnostic criteria for the early and differential diagnosis of bacterial sepsis in Kano, Nigeria.

EPIDEMIOLOGICAL LANDSCAPE OF BACTERIAL SEPSIS IN KANO

Understanding the local epidemiology of bacterial sepsis is paramount for developing relevant diagnostic and therapeutic guidelines. Studies from Kano and other parts of Nigeria have revealed a dynamic and challenging bacteriological profile [Table 1].[10-13]

Table 1: The common bacterial isolates from sepsis in Kano.
Pathogen type Common isolates Prevalence notes
Gram-negative Escherichia coli Constitutes most isolates, with some studies reporting rates as high as 60-70%[4,18-20]
Gram-positive Staphylococcus aureus High prevalence of isolates reported, with some studies reporting rates as high as 43-60%[21-23]

This epidemiological pattern is further complicated by the high prevalence of AMR.[14,15] Resistance to commonly used first-line empirical antibiotics such as ampicillin and gentamicin is widespread. Although newer agents such as amikacin and fluoroquinolones show better in vitro activity, their use is limited by cost and the risk of promoting further resistance.[16,17] This underscores the urgent need for diagnostic strategies that can rapidly identify the causative organism and its susceptibility profiles for better management and good prognosis.

CURRENT DIAGNOSTIC PARADIGMS AND THEIR LIMITATIONS

The diagnosis of bacterial sepsis in Kano, as in many similar settings, relies on a combination of clinical assessments, scoring systems, and laboratory tests.

Clinical criteria and scoring systems

The international consensus definitions for sepsis have evolved from the Systemic Inflammatory Response Syndrome (SIRS)-based criteria (Sepsis-2) to the Sequential Organ Failure Assessment (SOFA) and quick SOFA (qSOFA) scores (Sepsis-3).[1] While Sepsis-3 offers improved prognostic accuracy, its implementation in resource-limited settings can be challenging because of the requirement for laboratory measurements that may not be readily available. Consequently, the SIRS criteria and clinical judgment remain central to bacterial sepsis recognition in many Nigerian hospitals.

In the pediatric and neonatal contexts, tools such as the hematological scoring system (HSS) have shown considerable utility. The HSS, which evaluates parameters such as the immature-to-total neutrophil ratio and platelet count, serves as a simple, rapid, and cost-effective screening tool for the early diagnosis of neonatal sepsis.[24]

Laboratory diagnostics

Blood culture remains the gold standard for the definitive diagnosis of sepsis, enabling pathogen identification and antimicrobial susceptibility testing to be performed.[25] However, its utility in settings such as Kano is hampered by several factors.

  • Low sensitivity: Reported sensitivity is often low (25-40%), particularly if antibiotics are administered before sample collection.[26,27]

  • Long turnaround time: The 48-72 h wait for results is too long to guide initial, critical treatment decisions.[28]

  • Cost and infrastructure: Automated culture systems e.g. Bacterial Detection System (BACTEC), while available in some tertiary centers, such as Aminu Kano Teaching Hospital (AKTH), are expensive to procure and maintain.

EMERGING BIOMARKERS AND TECHNOLOGIES FOR DIFFERENTIATED DIAGNOSIS

The limitations of conventional methods have spurred research into novel biomarkers and technologies that can provide rapid, accurate, and actionable diagnostic information.

Host-response biomarkers

Several biomarkers are being investigated for their ability to detect sepsis early and potentially differentiate between Gram-positive and Gram-negative infections. These include:

  • Procalcitonin (PCT): PCT is a well-established biomarker for bacterial infections. Studies suggest that PCT levels are often significantly higher in patients with Gram-negative bacteremia as compared to those with Gram-positive infections, making it a potentially valuable tool for early differentiation.[29,30]

  • Interleukin-6 (IL-6): As an early and potent pro-inflammatory cytokine, IL-6 levels rise rapidly in response to infection. It has shown promise in the early diagnosis of bacterial sepsis and may also contribute to differentiating bacterial inflammation from other forms of inflammation.[31]

  • Neutrophil CD64: The expression of the CD64 antigen on neutrophils is upregulated during bacterial infection. It has demonstrated high diagnostic accuracy for sepsis, and some evidence suggests that its expression levels may differ between Gram-negative and Gram-positive stimuli.[32]

Advanced diagnostic technologies

  • Molecular diagnostics: PCR-based assays can detect bacterial DNA directly from blood within hours, offering a significant time advantage over culture.[33] Although cost remains a major barrier to widespread adoption in Kano, the development of more affordable, targeted molecular panels based on local epidemiology could be a game-changer.

  • Point-of-care testing (POCT): The development of rapid POCT for sepsis biomarkers (e.g., lactate, CRP, and PCT) is a critical area of innovation. These tests can be performed at the bedside with minimal equipment, providing real-time data to support clinical decision-making in emergency and primary-care settings.

A FRAMEWORK FOR THE FUTURE OF BACTERIAL SEPSIS DIAGNOSTICS IN KANO

Improving the early and differential diagnosis of bacterial sepsis in Kano requires a multi-faceted approach that is both technologically innovative and pragmatically grounded in the local context of Nigeria. The proposed framework includes the following:

  • Strengthening surveillance: First, continuous and robust surveillance of local bacterial pathogens and their AMR patterns is essential to inform empirical treatment guidelines and design targeted diagnostic panels.

  • Integrated diagnostic algorithms: It will also involve the development of algorithms that combine clinical scoring systems (such as qSOFA and HSS) with a tiered biomarker approach. For instance, a positive clinical screening outcome could trigger a rapid POCT for lactate and CRP, with a subsequent PCT or IL-6 test to guide the initial choice between broad-spectrum antibiotics targeting Gram-negative versus Gram-positive organisms.

  • Adoption of cost-effective technologies: Prioritize the evaluation and adoption of affordable molecular and POCT platforms validated for the specific epidemiological and operational realities of northern Nigeria in general, including Kano.

  • Education and training: Investing in continuous training of healthcare workers on the latest sepsis guidelines, appropriate use of diagnostic tools, and principles of antimicrobial stewardship.

CONCLUSION

The development of effective diagnostic criteria for the early and differential diagnosis of bacterial sepsis in Kano is a critical priority for reducing the high burden of bacterial sepsis-related mortality in the region. While significant challenges remain, a strategy that leverages an improved understanding of local epidemiology, integration of clinical scoring with advanced biomarkers, and embracing cost-effective technologies holds promise for transforming sepsis care in the area. By tailoring diagnostic innovations to the specific needs and constraints of resource-limited settings, it is possible to create a more resilient and effective healthcare response to this deadly syndrome.

Author’s contribution

SUM: Conceptualization, methodology, writing – original draft; AOA: Data curation, formal analysis, visualization; MAA: Supervision, writing – review & editing.

Ethical Approval

Institutional Review Board approval is not required.

Declaration of Patient Consent

Patient consent is not required as no patients are involved in the study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript, and no images were manipulated using AI.

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