Liver abscess caused by multidrug-resistant pathogen Stenotrophomonas maltophilia: A rare case report

ABSTRACT

Intra-abdominal infections are often implicated in the causation of liver abscesses, and the transmission occurs via the vascular route. We report a rare case of abscess of the liver, Stenotrophomonas maltophilia being the etiological agent, in a 25-year-old female residing in Lucknow, India. S. maltophilia is a common nosocomial pathogen responsible for causing pneumonia, bacteremia, meningitis, endocarditis, gastrointestinal, ocular, skin, soft tissue, bone, joint, urinary tract infections, and even septic shock, especially in intensive care units. However, very few case reports are from India and globally, highlighting it as a pathogen in a liver abscess case. Hence this study is relevant in the context of providing case details that can help clinicians and microbiologists to suspect and diagnose more such cases that might be missing in history.

Introduction

A hepatic abscess is a pus-filled collection in the liver developing either from hepatic injury or disseminated intra-abdominal infection via the portal vein.[1] In the context of developing a liver abscess, the high-risk groups include patients on chemotherapy, individuals suffering from acquired immune deficiency syndrome (AIDS), and those who have undergone transplantation surgery as they are immunocompromised and are prone to develop opportunistic infections.[2] Patients having abscesses in the liver mostly present with fever, right upper abdominal pain, and features of hepatitis like yellowing discoloration of sclera/skin. Hence it can mimic pathologies like viral hepatitis, appendicitis, and cholecystitis.[1] Stenotrophomonas maltophilia is a well-known nosocomial pathogen but is rarely reported to cause a liver abscess. The organism is an aerobic gram-negative bacillus that can cause significant morbidity and mortality in severely immunocompromised and debilitated patients.[3] As very few cases of liver abscess caused by S. maltophilia have been reported in a non-immunocompromised patient from India, hence this study is a relevant addition in the context of providing case details that can help clinicians and microbiologists to suspect and diagnose more such cases that might be missing in history.

Case Description

A 25-year-old female was admitted to a private hospital with chief complaints of fever for nine days and abdominal pain for seven days. Fever was high grade, intermittent, and associated with chills and rigor. On ultrasonography (USG) evaluation, she was found to have a liver abscess. She received intravenous antibiotics, and the abscess was aspirated. But high-grade fever and pain abdomen persisted. She was referred to the surgical gastroenterology department of our hospital for further management. Her history was insignificant. Menstrual history revealed irregular menses. On general examination, the patient was conscious but ill-looking, febrile- 103.2°F, pulse rate- 114/minute, respiratory rate-20 breaths/minute, blood pressure-122/74 mm Hg. Pallor/icterus/clubbing/cyanosis/edema/lymphadenopathy were all absent. On systemic examination, the abdomen was soft, distended, and tender. The rest of the systemic examination was normal. Laboratory investigations are summarized in Table 1.

Table 1.

Summary of laboratory investigations performed in the present case study

Investigation	Result	Reference range
Haemoglobin (g/dL)	10.4	12-15
Total leucocyte count (cells/mm3)	33600	4000-11000
Differential count (%)	Neutrophil (N)-93%, Lymphocyte (L)-6%, Eosinophil (E)-1%	(N=40%-80%, L=20%-40%, E=1%-6%)
Platelet count (lac cells/mm3)	5	1.5-4.5
C-reactive protein (mg/L)	126	0-6
Serum urea (mg/dL)	25.6	10-45
Serum creatinine (mg/dL)	0.71	0.5-1.4
Total bilirubin (mg/dL)	1.2	0.3-1.4
Direct bilirubin (mg/dL)	0.8	0-0.4
Serum glutamic oxaloacetic transaminase (IU/L)	100	0-40
Serum glutamic pyruvic transaminase (IU/L)	50	0-40
Serum alkaline phosphatase (IU/L)	378	50-240
Serum protein (gm/dL)	6.8	6-7.8
Serum albumin (gm/dL)	2.9	3.5-5
Prothrombin time (seconds)	24.8	11-15
International normalized ratio	1.9	0.8-1.2
Serum amylase (IU/L)	22.3	31-107
Serum lipase (IU/L)	15.1	13-60

USG abdomen showed a poorly defined hypoechoic lesion 63 × 55 × 27 mm in the left lobe with peri-hepatic collection suggestive of a ruptured liver abscess. For microbiological investigation, pus was drained and was sent for microscopy, culture, and antimicrobial susceptibility (c/s), based on which infection by S. maltophilia was detected as susceptible to levofloxacin. The isolate was identified based on the protein profile using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The patient had multiple episodes of vomiting during her stay in the hospital. Management included the administration of antipyretic (paracetamol), antiemetic (ondansetron), drainage of pus, and organism-specific therapy in the form of levofloxacin (though broad-spectrum antibiotics were given initially). The condition of the patient gradually improved, and hence she was discharged.

Discussion

Liver abscesses can be caused by bacteria, fungi, or even a parasite. Amebic liver abscesses are more common in areas where Entamoeba histolytica is endemic, while pyogenic abscesses are more common in developed countries, and overall, amoebae are the more common cause of liver abscess.[2] The various organisms which have been implicated in the etiopathogenesis of liver abscess are Escherichia coli, Klebsiella pneumoniae, staphylococci, enterococci, bacteroides, Corynebacterium jeikeium, microaerophilic streptococci, anaerobic streptococci, Salmonella Typhi, and Proteus vulgaris.[2,4,5] Datta et al.[6] reported the first case of liver abscess caused by Streptococcus constellatus from India (Chandigarh) in the year 2017. Other studies from outside India also reported such cases earlier in history.[7] Shigefuku et al.[8] reported three cases of pyogenic liver abscess due to Streptococcus anginosus group in Japanese patients, out of which two were coinfected with anaerobic bacteria. S. maltophilia is a common nosocomial pathogen responsible for causing pneumonia, bacteremia, meningitis, endocarditis, gastrointestinal, ocular, skin, soft tissue, bone, joint, urinary tract infections, and even septic shock, especially in intensive care units.[3] Mohanty et al.[9] from India reported a case of liver abscess by S. maltophilia in a 45-year-old chronic alcoholic. They diagnosed it by the culture of the ultrasound-guided liver aspirate sample followed by identification by VITEK 2™ Petri et al.[10] reported a case of melioidosis-like liver abscess caused by S. maltophilia in a non-immunocompromised patient (a Chinese man living in Hungary). Inviati et al.[11] reported a complicated case of multiorgan involvement (liver, left eye) due to S. maltophilia infection resulting in hepatic abscess and blindness. Infections caused by S. maltophilia can occur in immunocompromised and rarely in non-immunocompromised individuals. With the advent of MALDI-TOF MS, cases are increasingly being reported. The prevalence and severity of infection by S. maltophilia is still more common in immunocompromised persons.

Computed tomography and USG are highly accurate and commonly used modalities of diagnosis in the case of liver abscesses, but USG is a little more preferred in terms of cost-effectiveness.[12] While culture is the usual method of establishing an etiological diagnosis in the case of pyogenic liver abscess, amebic abscesses are routinely detected by serology or molecular methods (if facilities are available).[13] Management of pyogenic liver abscess includes both antibiotic therapy and drainage of the abscess. An amebic abscess can be treated with a nitroimidazole drug, followed by a luminal agent. Routine aspiration of amebic liver abscesses is not usually recommended except in the case of larger abscesses in which percutaneous needle aspiration can be done.[14] S. maltophilia strains are naturally resistant to various drugs like beta-lactam antibiotics or aminoglycosides; hence limited drug options are available to treat such infections. Levofloxacin, chloramphenicol, and trimethoprim-sulfamethoxazole are the preferred treatment options.[15]

Conclusion

The present study highlights the fact that S. maltophilia can be the possible cause of the liver abscess. Though rare, clinicians should include it as an etiological agent in differential diagnosis while evaluating such cases.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

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Conflicts of interest

There are no conflicts of interest.