Analysis of Blood Cultures of Patients Presenting to the Emergency Department in a Tertiary Healthcare Hospital in Mumbai

INTRODUCTION

Sepsis is the combination of a known or suspected infection and an accompanying systemic inflammatory response. Sepsis, severe sepsis and septic shock are terms used to describe the body’s systemic responses to infection. Severe sepsis is sepsis with acute dysfunction of one or more organ systems, and septic shock is a subset of severe sepsis. It is common and frequently fatal. Underlying illness, increased age and multisystem organ failure are major risk factors for mortality from sepsis.^1,2

The prognosis of the patient with severe sepsis is related to the number of dysfunctional organs. Progression from signs of the inflammatory response to sepsis/severe sepsis and septic shock is associated with incrementally higher mortality risk. The transition to serious illness may occur during the critical ‘golden hours’ when definitive recognition and treatment provide maximal benefit in terms of outcome. Therefore, early recognition of sepsis and its appropriate treatment is of paramount importance in reducing mortality.³

One of the essential facets of sepsis management to maximise survival rates is the rapid administration of appropriate antimicrobials. Several studies have reported that each hour’s delay in the administration of appropriate antimicrobials is associated with a measurable increase in mortality in patients with sepsis or septic shock.⁴ Further, failure to initiate appropriate empiric therapy in patients with sepsis and septic shock has been associated with a substantial increase in mortality.^5,6

Based on this evidence, the Surviving Sepsis Campaign (SSC) guidelines strongly recommend that empiric broad-spectrum therapy be conducted with one or more antimicrobials as soon as possible after the recognition of sepsis or septic shock, to cover all likely pathogens, including bacterial, fungal or viral coverage⁷ ideally within 1 hour of sepsis recognition.⁸

However, the distribution of causative pathogens has changed over time,⁹ and the global rise in antimicrobial-resistant pathogens has made it difficult to routinely conduct empiric broad-spectrum antimicrobial therapy.^9,10 To optimise the accurate selection of initial antimicrobial agents, clinicians should consider the various factors associated with the causative pathogens, including:

• Patient pre-existing comorbidities,

• Prior knowledge of pathogens known to colonise the patient,

• Prior antibiotic exposures and

• The local pattern of causative pathogens, antibiotic resistance and zoonotic pathogens.^11,12

Furthermore, there is no one-size-fits-all empiric antimicrobial therapy for sepsis because the typical pathogen profile varies according to the anatomical site of infection. Although there are multiple lines of evidence related to the causative pathogens in paediatric sepsis,^13,14 there are only limited reports in adult sepsis. Blood cultures taken from patients attending emergency departments are an important antibiotic stewardship tool, which directly influences patient management.¹⁵

Therefore, updating knowledge on the current distribution of causative pathogens in adult sepsis is required to initiate appropriate antimicrobial therapy. The aims of this study were to provide updated and detailed information on the distribution of causative pathogens in adult sepsis and study their antibiotic-susceptibility pattern.

AIM AND OBJECTIVES

MATERIALS AND METHODS

METHODOLOGY

• As per predefined, inclusion and exclusion criteria patients were included in the study.

• All these patients were evaluated thoroughly by clinical, radiological and laboratory methods.

• Most of the patients in the study sample were from the Mumbai region barring a few who were referred from other regions such as Kalyan, Thane and Navi Mumbai.

• These patients were provisionally diagnosed to have sepsis in the ER, barring a few who were diagnosed elsewhere and referred here.

• Blood cultures were collected from peripheral veins, other sites were excluded because these could confound the results.

• Each patient was started on empirical therapy as per the current protocol.

• Susceptibility testing was done by Kirby–Bauer disc diffusion method and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines – 2012.

• Empirical upgradation of antibiotics or change in antibiotics was done as per the culture sensitivity report.

RESULTS

Mean age of the study cases was 59.3 years with 59.5% cases that belonged to elderly age group (Fig. 1).

Male predominance was seen among cases of suspected sepsis with 56.2% males–43.8% females (Fig. 2).

The most common organism isolated from cases with sepsis was Escherichia coli (45.5%) followed by Klebsiella (13.2%), Salmonella (10.7%), Stenotrophomonas (7.4%) and Pseudomonas (5%). Among Gram-positive organisms, Staphylococcus aureus was the most common organism isolated (1.7%) (Table 1).

Overall Gram-negative isolates were seen in 95% of cases, while Gram-positive isolates were seen in only 1.7% cases (Table 2).

DISCUSSION

Sepsis is the combination of a known or suspected infection and an accompanying systemic inflammatory response. The prognosis of the patient with severe sepsis is related to the number of dysfunctional organs. One of the essential facets of sepsis management to maximise survival rates is the rapid administration of appropriate antimicrobials. Several studies have reported that each hour’s delay in the administration of appropriate antimicrobials is associated with a measurable increase in mortality in patients with sepsis or septic shock.⁴

Based on this evidence, the Surviving Sepsis Campaign (SSC) guidelines strongly recommend that empiric broad-spectrum therapy be conducted with one or more antimicrobials as soon as possible after the recognition of sepsis or septic shock, to cover all likely pathogens, including bacterial, fungal or viral coverage.⁷

However, the distribution of causative pathogens has changed over time,⁹ and the global rise in antimicrobial-resistant pathogens has made it difficult to routinely conduct empiric broad-spectrum antimicrobial therapy.^9,10 Therefore, updating knowledge on the current distribution of causative pathogens in sepsis is required to initiate appropriate antimicrobial therapy.

In this study, we thus aimed to find out the common pathogens/ microbes and their respective antimicrobial drug susceptibility in suspected sepsis patients presenting to the Emergency Department. The study included 121 suspected sepsis patients arriving to Emergency Department whose blood cultures are being sent from the Emergency room (ER).

SUMMARY AND CONCLUSION

CONCLUSION

This study observed the microbiological profile and antibiotic-susceptibility pattern of adult sepsis cases. Gram-negative organisms are the most common isolates observed in this study with E. coli being the predominant pathogen followed by Klebsiella. High-level antimicrobial resistance was observed in sepsis cases for commonly used antimicrobials like fluoroquinolones and cephalosporins.

This knowledge is very necessary to treat sepsis cases empirically in the hospital settings. Hence, regular surveillance should be carried out to determine the local prevalence of organisms and antimicrobial susceptibilities in order to guide the proper management of adults’ sepsis cases.

Post cardiac-sustained life care or post cardiopulmonary arrest resuscitation status at the time of sepsis diagnosis have been excluded from the study as these result in changes in the body that mimic sepsis-like syndrome and could act as a confounding factor in the study. Pregnant females have been excluded from the study as the evaluation and management of maternal sepsis are complicated because of physiological changes that occur during pregnancy.

ORCID

Deepak Kishor Sharma https://orcid.org/0009-0005-3162-6414

Sandeep B Gore https://orcid.org/0009-0004-0585-2015

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