Emerging and Re-emerging Pathogens Causing Blood Stream Infections (BSI) in Hospitalized Patients at a Tertiary Care Hospital

TL;DR

This study identifies emerging and re-emerging bacteria causing bloodstream infections in hospitalized patients and highlights their antibiotic susceptibility patterns.

Contribution

The study provides new insights into the frequency and antibiotic resistance of emerging and re-emerging bacterial pathogens causing bloodstream infections.

Findings

Burkholderia cepacia was the most frequently isolated emerging pathogen, showing highest susceptibility to cotrimoxazole and minocycline.

Paired blood cultures improved detection of emerging pathogens, with 15.82% of isolates being E&Re pathogens.

Automation aids in timely identification and management of these infections, improving patient outcomes.

Abstract

Background and objectives

Infectious diseases known as bloodstream infections (BSIs) are characterized by the presence of live microorganisms in the bloodstream, which are subsequently confirmed by the positive results of one or more blood cultures. These conditions cause or have caused an inflammatory response, which is reflected in changes to hemodynamic, laboratory, and clinical parameters. In the current scenario, hospitalized patients are more likely to die from BSI caused by a number of emerging and re-emerging (E&Re) bacteria. Re-emerging means recurrence or new outbreaks of old infectious diseases with important public health relevance. It is difficult to identify these species using conventional identification methods. Automated techniques can be used for identification and testing for antibiotic susceptibility. The objective of this research is to ascertain the frequency of newly identified E&Re bacterial pathogens that cause BSIs, as well as their pattern of antibiotic susceptibility, risk factors, and post-BSI outcomes.

Materials and methods

This was a retrospective study, carried out over the course of two years (June 2022 to May 2024) at the Department of Microbiology, Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar. All the relevant data were collected from electronic records and entered into an Excel sheet for analysis. An identification/sensitivity testing system (VITEK 2, bioMérieux, Marcy-l'Étoile, France) and automated blood culture (BacT/Alert 3D, bioMérieux, Marcy-l'Étoile, France) were used to process the samples.

Results

In total, 5730 (18%) of the 31850 blood cultures showed positive microbial growth. Paired bottle culture, which came to be positive, was 2718 (47.43%). A total of 430 (15.82%) E&Re pathogens and 2288 (84.17%) common pathogens were isolated from the paired positive blood culture, showing their strong association with BSI. Out of the total E&Re pathogens, bacterial pathogens isolated were 363 (84.41%), and the fungal pathogen (Candida auris) isolated was 67 (15.58%). The predominant bacterial pathogen isolated was Burkholderia cepacia 126 (29.30%), followed by Sphingomonas paucimobilis 66 (15.34%) and Elizabethkingia meningoseptica 54 (12.55%). Burkholderia cepacia shows maximum susceptibility to cotrimoxazole and minocycline.

Conclusion

For optimum isolation, identification, and treatment of BSI pathogens, paired blood culture should be sent to the microbiology laboratory along with the clinical and antibiotic history. These E&Re pathogens in blood culture should be considered as possible infectious agents and should not be ignored as probable contaminants. Early and precise management of patients with BSI is made possible by automation, which aids in the timely reporting of E&Re infections.