Clinical Challenges and Treatment Strategies for Rare ICU Pathogens: A Case Series

INTRODUCTION

The emergence of rare bacterial strains presents a significant clinical concern, posing treatment and infection control challenges in the intensive care unit (ICU). In this case series, we present an intriguing investigation into detecting and managing three uncommon bacteria Pluralibacter gergoviae, Stenotrophomonas maltophilia, and Elizabethkingia anopheles from cultures of ICU patients. Understanding these pathogens’ clinical implications and antibiotic susceptibilities is critical for effective management and infection control strategies within healthcare facilities.

CASES DESCRIPTION

DISCUSSION

Pluralibacter gergoviae belongs to the Enterobacteriaceae family. It is an opportunistic bacteria found in the urinary tract and is associated with antibiotic-resistant outbreaks in several hospitals. It has also been cultured from respiratory and blood samples.¹ The resistance of P. species to antibiotics has been a focal point of interest, with many seeking to expand the data on the newer taxa within the genus. Due to their membrane structure, they are naturally resistant to fusidic acid, vancomycin, teicoplanin, telavancin, lincosamide, and rifampicin.² Tetracyclines, aminoglycoside antibiotics, carbapenems, and fluoroquinolones are active against them. However, they are only moderately sensitive to penicillin and ampicillin. They have moderate to high levels of sensitivity to cephalosporins, except cefoxitin, which they are resistant to.³ But, resistance to third-generation cephalosporins is quickly emerging due to extended-spectrum beta-lactamases’ production. Most of the species are sensitive to carbapenems, including ESBL producers, and are considered to be the preferred empiric therapy for serious Enterobacteriaceae infections.⁴

Stenotrophomonas maltophilia is a gram-negative, non-fermenting, aerobic bacteria which is previously known as Pseudomonas maltophilia or Xanthomonophilia.⁵ It has very low virulence and is considered a commensal to human beings. It causes opportunistic infections. The respiratory system is most commonly involved, but it can also cause infections in the eyes, biliary system, bones, joints, and urinary system.^6,7 Risk factors for S. maltophilia infection include dialysis dependence, cystic fibrosis, and other chronic respiratory illnesses, hematologic malignancy, neutropenia, human immunodeficiency virus infection, and organ transplant recipients.⁸ The first-line treatment for S. maltophilia is trimethoprim-sulfamethoxazole. Studies indicate that it is bacteriostatic for S. maltophilia and must be given at higher doses to be effective.⁹ S. maltophilia is also sensitive to tetracyclines and fluoroquinolones, and these can be used as alternative treatment if needed. The duration of treatment is usually seven days, but the treatment may need to be continued for up to two weeks in immunocompromised patients and bacteremia.¹⁰

Elizabethkingia anophelis is a gram-negative, aerobic, non-motile rod belonging to the Flavobacteriaceae family. E. anophelis is ubiquitous and is found in soil, water, and healthcare settings.¹¹ It has emerged as an opportunistic human pathogen involved in neonatal meningitis and sepsis as well as nosocomial infections in adults with underlying medical conditions like malignancy, diabetes, and COPD. In previous studies, the case fatality rate of patients with E. anophelis infection has been 24–34%.¹² Hence, E. anophelis bacteremia should be considered clinically significant, and sensitivity-based antibiotic therapy should be initiated as it is a multi-drug resistant organism.¹³ The antibiotic susceptibility pattern of this organism is not widely known. The organism was resistant to fluoroquinolones and third-generation cephalosporins but was sensitive to minocycline, which was initiated immediately. The finding of this isolate could be attributed to anemia, prolonged hospital stay, multiple in-dwellings, and immunocompromised status of our patient.

CONCLUSION

This case series underscores the clinical challenges of rare bacterial strains such as P. gergoviae, S. maltophilia, and E. anophelis in ICU settings. These pathogens, though uncommon, exhibit significant clinical impact, particularly in immunocompromised patients or those with complex medical conditions. Effective management hinges on prompt identification through culture-based diagnostics and tailored antibiotic therapy based on susceptibility patterns. The cases highlighted the importance of vigilance in infection control practices within healthcare facilities. Moving forward, continued surveillance and research into the antibiotic resistance profiles of these organisms are crucial for enhancing treatment outcomes and minimizing the spread of nosocomial infections.

REFERENCES

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