1. Introduction
The genus Cedecea belongs to the family Enterobacteriaceae. Cedecea consists of six species and three of these species are known human pathogens: Cedecea davisae, Cedecea lapagei, and Cedecea neteri [1]. Although discovered in 1977, it was not until the year 2006 that the species C. lapagei became known as a pathogenic bacterium [2]. It has been isolated in sputum, BAL specimen, blood, etc. [3] [4], but it has not been found in exudate until now. A strain of C. lapagei was detected in the exudate from the wounded inpatient by clinic laboratory of our hospital. More important, it’s a mixed infection with Proteus vulgaris.
2. Case Report
The male patient, 42 years old, a worker, was sent to our hospital due to a motorcycle fall 6 hours ago. In the emergency department, he was admitted to our hospital’s hand and foot surgical ward with “multiple injuries, multiple open fractures and dislocations of the right foot, multiple rupture of blood vessels, nerves and tendons of the right foot, skin and soft tissue defects of the right foot, pelvic fracture, hematoma of the right ilium, and fracture of the right fibula head”. The patient has clear mind, poor spirit, no obvious abnormality in heart and lung, and no water intake. He used to be in good health and had a personal history of 20 cigarettes/day for 20 years, 200 gram/day alcohol consumption for 10 years.
There was no family genetic disease or infectious history. On the day of admission, the patient was given surgical treatment. After the operation, the patient was treated with anti-bacterial, detumescence, fracture promotion, wound healing, anticoagulation, antispasmodic, and heat preservation with baking lamp. Although the wounds were well matched, there was some more liquid exudation. The patient was given iodophor disinfection, aseptic auxiliary material replacement, and the exudate was taken for bacterial culture and drug sensitivity test. Informed consent was obtained from the patient.
3. Bacterial Culture and Identification
The exudate was inoculated into blood culture medium and Chinese blue culture medium, and cultured in 36˚C incubator for 24 hours. There were small round colonies with gray white, moist and smooth edges, without hemolytic ring. The microscopic examination showed Gram-negative bacteria. In addition, there were migratory membrane colonies in the blood culture medium. The round colonies and membranous colonies were identified as C. lapagei and Proteus vulgaris by Vitek™ 2 compact system (BioMérieux, France) following the manufacturer’s instructions.
4. Drug Sensitivity Test
Antimicrobial susceptibility testing was determined by the automated Vitek™ 2 compact system using AST-GN13 susceptibility cards. One hundred and forty-five microliter bacterial suspension of a 0.5-McFarl and turbidity was mixed with 3 mL 0.45% NaCl solution. The AST-GN13 card filled with the mixture was used. The E. coli ATCC25922 was used as quality control. Drug sensitivity test showed that C. lapagei was resistant to Ampicillin, cefazolin, imipenem and Sulfamethoxazo. It was mediated to ampicillin/sulbactam, gentamycin, tobramycin, ciprofloxacin and levofloxacin (see Table 1). The drug sensitivity test of Proteus vulgaris showed that it was resistant to ampicillin, cefazolin, imipenem, amikacin, gentamicin, ciprofloxacin, sulfamethoxazo and sensitive to piperacillin/tazobactam, cefotaxime, ceftazidime, cefatriaxone, cefepime, aztreonam, ertap nan, levofloxacin (see Table 2).
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Table 1. Drug sensitivity test of C. lapagei.
Note: MIC, minimum inhibitory concentration (μg/ml); R, resistant; S, susceptible; I, intermediate.
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Table 2. Drug sensitivity test of Proteus vulgaris.
Note: MIC, minimum inhibitory concentration (μg/ml); R, resistant; S, susceptible; I, intermediate.
5. Prognosis and Outcome
After changing fresh dressing for the wound once a day and constant anti-infection treatment with the addition of levofloxacin, the exudate of the wound was continuously reduced apparently. After three days, the subsequent bacterial culture and identification showed that there was no bacterial growth in the exudate. The patient was well recovered and discharged soon afterwards.
6. Discussion
C. lapagei is a member of the Enterobacteriaceae family and is an uncommon opportunistic pathogen. Its susceptible population is individuals with low or suppressed immune function, such as patients with granulocytopenia, tumor chemotherapy, organ transplantation, large-scale surgery or trauma [2] [5], such as it can follow cement-related chemical burn injury [6]. There are very few reports of isolation of this organism from human biological samples; it is also found to be a pathogen in elderly or otherwise life-threatening conditions [7], for example in a patient with chronic obstructive pulmonary disease [8]. Biswal et al. presented a rare case of a patient with underlying malignancy of buccal mucosa, who developed an oral ulcer superinfected with C. lapagei and this is the first case of C. lapagei from India detected in a cancer patient [9]. C. lapagei can also cause ventilator-associated pneumonia and sepsis in Neonatal Intensive Care Unit [10].
We presented the first rare case of simultaneous infection of two bacteria including C. lapagei and Proteus vulgaris from the exudate of the traumatic wound in the world. But their relevance between C. lapagei and Proteus vulgaris has yet to be elucidated. It was reported that C. lapagei can produce New Delhi metallo-β-lactamase-1 (NDM-1) in some certain areas [11]. NDM-1 is a carbapenemase able to hydrolyze nearly all available β-lactam antibiotics, endangering efficacious antibacterial treatments [12]. Further studies are needed to understand its biology characteristics and the role in the mode of transmission, the spectrum of infection, and treatment options. There is a great need for physicians to cognize the emerging pathogens and know their antibiotic resistance profiles.
Acknowledgements
This work was supported by the project of science and technology development research center of ministry of health (Grant number: 28-10-2), the Natural Science Foundation of Shandong Province (Grant number: ZR2010HL038), Jining Municipal Science and Technology development projects (Grant number: 2012jnjc16 & 2014jnnk23), Shandong provincial medical and health science and technology development project (Grant number: 2013WS033), Shandong Province Traditional Chinese medicine science and technology development project (Grant number: 2015-244), and the Project of Shandong Province Higher Educational Science and Technology Program (Grant number: J15LL11). Nursery Program of Affiliated Hospital of Jining Medical University (Grant number: MP-2018-008).
NOTES
*These authors contributed equally to this work.
#Corresponding author.