How Doctors Really Decide: Inside the Fight Against Drug-Resistant Klebsiella Bloodstream Infections

When a critically ill patient develops a bloodstream infection caused by carbapenem-resistant Klebsiella pneumoniae, the clock starts immediately. This bacterium, a Gram-negative pathogen that has acquired resistance to carbapenems, the last-line beta-lactam antibiotics often reserved for the most severe hospital infections, is associated with high mortality in intensive care units. Yet while quantitative trials have long measured how well specific drugs work against such infections, surprisingly little has been documented about how clinicians actually navigate the tangled, real-world process of choosing treatment when the options are few, the evidence is incomplete, and the stakes are measured in lives.

A new qualitative study published in BMC Infectious Diseases by researchers at Manipal Academy of Higher Education and affiliated hospitals in Karnataka, India, offers one of the most detailed portraits to date of that hidden decision-making process. Led by Asha K. Rajan of the Department of Pharmacy Practice and Vishal Shanbhag of the Department of Critical Care Medicine, the team interviewed fifteen physicians drawn from multiple specialities, including critical care, microbiology, infectious diseases and general medicine, all of whom were directly involved in managing critically ill patients with carbapenem-resistant K. pneumoniae bacteraemia. The study was funded by the Indian Council of Medical Research and conducted across institutions including Kasturba Medical College and Dr TMA Pai Hospital in Udupi.

The methodological approach is what sets the work apart from typical antibiotic studies. Rather than testing drugs, the researchers used semi-structured interviews and analysed the transcripts through a constructivist grounded theory framework, a qualitative technique that builds explanatory themes from the ground up through iterative coding, constant comparison and triangulation among investigators, supported by ATLAS.ti software. Participants were purposively sampled to capture a range of perspectives, and reporting followed the COREQ checklist, the recognized standard for transparency in qualitative research. The inductive analysis yielded seven themes and fifteen subthemes, and from these a central insight crystallized: antimicrobial decision-making is not a single choice but an iterative balancing act, one that pits the urgency of early effective treatment against evolving microbiological evidence, patient-specific toxicity, pharmacokinetic uncertainty, stewardship expectations and resource constraints.

The first and perhaps most consequential finding concerns time. Clinicians consistently reported prioritizing clinical risk and urgency before microbiological confirmation was available. In practical terms, this means that when a septic patient deteriorates, physicians often begin empiric therapy against suspected carbapenem-resistant organisms before blood cultures, susceptibility testing or molecular diagnostics can return an answer. The decision at this stage is driven by clinical judgment, local resistance patterns and the fear that delay allows the infection to gain ground. Only later, as culture results, minimum inhibitory concentration values and the patient’s response emerge, do clinicians modify the regimen, narrowing, broadening or switching agents in a continuous cycle of reassessment.

This iterative loop exposes a fundamental tension in modern infectious disease medicine: the diagnostics that should guide therapy are often too slow to shape the earliest and most critical decisions. The study found that although microbiological and molecular diagnostics, including polymerase chain reaction-based assays, were highly valued by physicians, their influence was constrained by turnaround times and interpretative challenges. A culture and susceptibility report that arrives forty-eight to seventy-two hours after admission arrives after the decisive therapeutic window has already begun to close. Physicians described having to act on probability rather than certainty, then retrofitting their choices to the laboratory evidence as it trickled in.

Toxicity and pharmacokinetics added a second layer of complexity. The antibiotics active against carbapenem-resistant K. pneumoniae, such as polymyxins, aminoglycosides and newer beta-lactamase inhibitor combinations, carry well-known risks of nephrotoxicity and other adverse effects, particularly in patients whose kidneys and livers are already compromised by critical illness. The interviewed physicians described continuously weighing efficacy against toxicity, adjusting doses according to patient-specific factors such as renal function and body weight, and relying on therapeutic drug monitoring where available to keep drug concentrations within a safe and effective range. The concept of the minimum inhibitory concentration, the lowest drug concentration that prevents visible bacterial growth, featured in their reasoning as a technical anchor, but its interpretation required expertise that not every setting could supply.

Antimicrobial stewardship, the institutional programs designed to preserve antibiotic effectiveness and curb resistance, emerged as a double-edged force in the interviews. On one hand, stewardship expectations pushed clinicians toward restraint, encouraging them to justify broad-spectrum or last-line agents and to de-escalate when possible. On the other hand, physicians described situations where stewardship dynamics created friction with clinical urgency, forcing them to negotiate between what they believed the patient needed and what the system’s guidelines, formularies and review committees permitted. The study suggests that stewardship is most effective when it functions as a collaborative dialogue rather than a bureaucratic gate, and that strengthening multidisciplinary stewardship is essential for optimizing care in these infections.

Structural constraints formed the third pillar of the findings, and they hit hardest in low- and middle-income settings like the one where the study was conducted. Cost, drug availability and communication gaps between departments, laboratories and prescribing teams all limited the delivery of optimal therapy. A physician might identify the ideal agent only to discover it was out of stock, unaffordable for the patient or unavailable in the required formulation. Communication breakdowns between microbiology and the bedside delayed the integration of laboratory findings into treatment plans. These system-level barriers, the authors argue, mean that improving outcomes requires more than education; it demands context-appropriate decision-support tools, timely diagnostics and interventions that address the supply chain and institutional infrastructure itself.

Perhaps the most forward-looking theme concerned learning. The study found that outcomes evaluation and experiential learning subsequently informed future treatment decisions, meaning that each patient’s trajectory became data for the next. Physicians who watched a regimen fail or succeed carried that experience forward, building an internal decision framework that no guideline could fully replicate. This finding underscores why understanding clinician decision-making processes is essential for designing effective strategies: guidelines that ignore the lived, iterative reality of intensive care prescribing risk being bypassed in the moments that matter most.

The authors conclude that the management of carbapenem-resistant K. pneumoniae bacteraemia extends far beyond drug choice, encompassing clinical urgency, diagnostic integration, pharmacokinetic uncertainty, stewardship dynamics and structural constraints. Their prescription for the future is concrete: decision-support tools calibrated to local contexts, faster diagnostics that can inform the first hours of therapy, strengthened multidisciplinary stewardship and system-level interventions that remove the barriers of cost and availability. As antimicrobial resistance continues to climb the World Health Organization’s priority lists, this study offers a rare and valuable window into the human judgment at the center of the antibiotic crisis, reminding the field that the fight against resistant superbugs is fought not only in laboratories but in the split-second, evidence-hungry decisions of physicians at the bedside.

Subject of Research: Clinician decision-making in antimicrobial treatment of carbapenem-resistant Klebsiella pneumoniae bacteraemia in critically ill patients

Article Title: Antimicrobial treatment decision-making for carbapenem-resistant Klebsiella pneumoniae bacteraemia in critically ill patients: a qualitative study

Article References: Rajan, A. K., Bhat, D., Eshwara, V. K., Varma, M., Umakanth, S., Thunga, G., & Shanbhag, V. (2026). Antimicrobial treatment decision-making for carbapenem-resistant Klebsiella pneumoniae bacteraemia in critically ill patients: a qualitative study. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14436-7

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14436-7

Keywords: Klebsiella pneumoniae, antimicrobial resistance, bacteraemia, antimicrobial stewardship, critical care, qualitative research, Antimicrobial, treatment, decision-making, carbapenem-resistant, Klebsiella, pneumoniae