A 79-year-old female presented to the department of acute geriatric medicine due to unintended weight loss of 6 kilogram in the last 6 month, loss of appetite and fatigue. The medical history was remarkable: exactly two years before admission she was admitted to the department of internal medicine in the same hospital because of thoracic pain on the right side with an intensity of 10 in the visual analog scale. In the computed tomography a spiculated pulmonary lesion of 30 mm diameter was detected in the right anterolateral upper lobe of the lung. The radiologist classified the lesion highly suspicious for cancer. A positron emission tomography confirmed the suspicion for cancer due to high activity in the fluorodeoxyglucose metabolism. A new detected pleural effusion was drained and amber fluid with bloody spots was analyzed. It revealed a mass of neutrophilic granulocytes, histiocytes and mesothelial cells, findings that were classified as reactive for inflammation. No tumor cells were found. Cultures for the detection of tuberculosis and anaerobic or aerobic germs were negative. Aminopenicillin was given parenterally and an appointment was made for bioptic clarification of the lesion for outpatients, an appointment that was not perceived because of negative attitudes of the patient against an invasive procedure.
Two years later, on admission to the department of acute geriatric medicine, she had a reduced general condition. On her right upper field, the respiratory sound was attenuated. Her skin was pale, and she was emaciated. The body mass index was 16 (ideal value 24–29, age and sex adjusted).
In the comprehensive geriatric assessment, we found 18,5 score points in the Mini Nutritional Assessment, indicating malnutrition and 95 score points (range 0-100 points, higher points indicating higher performance status) in the Barthel index, indicating the self-care uncompromised. The cognitive tests (Mini Mental test and Clock Performance Test) were unremarkable.
A repeated thoracic computer tomography indicated an enlargement of the lesion in the right upper lobe of the lung to 9 x 9 x 7,5 cm diameter with a similar lesion in the right lower field of the lung being highly suspicious for metastasis. The lesion was spiculated, with an unshaped border and lobulated. The draining bronchus stopped abruptly in front of the lesion. The lymph nodes were normal; we noted no destruction of the adjacent rips.
Laboratory findings of the peripheral venous blood sample were as following: Leucocytes 11300/mm³ (86,6 % neutrophils); hemoglobin count 9,9 g/dl; platelet count 334000/mm³.
Her serum chemistry results were as follows: [Na+], 135 mmol/l; [K+], 4.3 mmol/l; estimated glomerular filtration rate (MDRD formula) 51 ml/minute; C-reactive protein 115 mg/l. The results of liver metabolism were unremarkable. The test for COVID-19 virus (polymerase chain reaction test) was negative as well as the test for Mycobacterium tuberculosis (QuantiFERON®-TB Gold Test).
After drawing samples for blood cultures, a calculated therapy for suspected pneumonia was started with ampicillin plus sulbactam parenterally.
One set of blood cultures were sent to our microbiological laboratory and incubated in the Beckton and Dickinson (BD) Bactec™ Instrument, which provided a positive result for the aerobic bottle after an incubation period of 15 hours and 30 minutes. A Gram staining performed with the positive blood culture and the specimen was plated and incubated accordingly to the manufacturer`s protocol. The Gram staining showed short Gram-negative rods (Fig. 1). After 24 hours of incubation at 35°C under aerobic conditions growth could be seen on PolyViteX Agar, Columbia Blood Agar and MacConckey media (BD) (Fig. 2), showing a mucoid morphology as previously described by Chavez JA et al.(2017)(4). Cultivated bacteria were further analyzed with a Bruker Microflex MALDI-TOF (Matrix assisted laser desorption ionization - time of flight) mass spectrometer setup. Data which were obtained from the Bruker Microflex setup showed a strong result for Wohlfahrtiimonas chitiniclastica according to the score of 2,56 and a consistency rating of A+++ due to the manufacturer`s protocol, using the research version 4.1 model-based testing compass database from Bruker Daltonics. Since the MALDI TOF analysis provided a solid result of > 2, which secures identification at species level. Therefore, no further diagnostic procedures were necessary to provide the clinician with a feasible result.
To provide guidance for adequate therapy in this case, our laboratory conducted an elipsometer-tests (BD) and interpreted the results according to EUCAST (European Committee on antimicrobial susceptibility testing) PK/PD (pharmacokinetic/pharmacodynamic) non-species related breakpoints (Table 1), since species specific breakpoints were absent (5, 6). The strain of Wohlfahrtiimonas chitiniclastica showed very low minimum inhibitory concentrations for all antibiotics indicating antibiotic treatment could be taken into account.
Table 1) Minimum inhibitory concentrations (MIC) testing of Wohlfahrtiimonas chitiniclastica for selected substances:
Antibiotic
|
MIC (µg/ml)
|
Remark for clinical use
|
Amoxicillin/Clavulanic acid
|
0,12
|
Yes
|
|
|
|
Piperacillin/Tazobactam
|
0,19
|
Yes
|
Cefotaxim
|
0,012
|
Yes
|
Cefepime
|
0,023
|
Yes
|
Imipenem
|
0,19
|
Yes
|
Ciprofloxacin
|
0,016
|
Yes
|
Trimethoprim/Sulfmethoxazole
|
0,19
|
not applicable
|
Along with the blood culture results an additional exposure history was performed. The results showed that the patient lived with a dog and was a cigarette smoker with an exposure of 30 pack years and denied drug use. The patient remained afebrile and without pain. Her chief complaints were fatigue and exhaustion. Blood cell counts and parameters of inflammation remained unchanged despite the advanced oncologic situation. We initiated nutritional support using supplements and a diet adjusted to the recommendations of the dietologist. Detailed consultation on further diagnostic and therapeutic options followed on several occasions and clinical visits were accompanied by the patient’s cohabitant. For personal reasons, the patient refused further diagnostic or therapeutic measures. In accordance with the patient’s wishes, we constituted a palliative care and finalised the antibiotic course after 8 days without consecutive laboratory controls. The further clinical course after discharge from hospital was unremarkable according to the report of her family doctor. Due to the increased need of care, the patient`s cohabitant established home nursing. The patient died 19 days after the discharge from hospital; no autopsy was performed due to the order of the family.