Abstract
Acinetobacter baumannii strains are isolated in up to 1% of nosocomial infections mostly from intensive care units immunocompromised patients and are associated with high mortality rates. A baumannii infections include pneumonia, urinary tract infection, endocarditis, skin and soft-tissue infections, surgical-site infection, meningitis, osteomyelitis, and septicemia. We report an extremely rare case of deep neck abscess due to multidrug-resistant A baumannii infection. The isolate strain was analyzed by a repetitive sequence-based polymerase chain reaction typing method: the isolate profile was compared with other strains obtained from isolates recovered in the hospital in that period. Our patient underwent 2 neck explorations and antibiotic treatment (tigecycline 50 mg, twice per day). Five weeks after admission, the patient was discharged in good general conditions. Considering the other obtained strains, 4 different profiles were identified, one as prominent (profile A, 18 isolates), the index case (B), and 2 others (C, D) as divergent.
1
Introduction
Deep neck infection means infection in the potential spaces and fascial planes of the neck, either abscess formation or cellulites . Although the occurrence of deep neck space infections has been declining since the advent and widespread diffusion of antibiotics , these infections are associated with significant morbidity and mortality rates. If life-threatening complications occur, such as descending mediastinitis, pleural empyema, pericarditis, pericardial effusion, epidural abscess, jugular vein or cavernous sinus thrombosis, venous septic embolus, carotid artery rupture, aorticopulmonary fistula, adult respiratory distress syndrome, acute renal failure, septic shock, or disseminated intravascular coagulation, the mortality rate may reach 40% to 50% . Early studies of the bacteriology of deep neck infections have pointed out 3 microorganisms: Staphylococcus aureus , Streptococcus pyogenes , and anaerobic bacteria. Nowadays, mixed infection with both aerobic and anaerobic bacteria becomes the rule .
We herein describe an extremely rare case of deep neck abscess due to multidrug-resistant (MDR) Acinetobacter baumannii infection in an immunocompetent elderly patient.
2
Case report
In June 2008, an 83-year-old female diabetic patient was transferred to our department because of right-sided submental swelling, odynophagia, and nightly fever with undulating trend from the Respiratory Intensive Care Unit (ICU) of Padova Hospital, Padova, Italy, where she had been admitted 12 days before for an exacerbation of chronic obstructive pulmonary disease. On physical examination, the patient showed a fluctuating right-sided submental 3-cm mass with red and hot overlying skin and intense pain at palpation. The superior airways were normal even if a 1-cm ulcerate lesion in the anterior floor of the mouth was present, probably because of dental prosthesis decubitus. At admission, the white blood cell count was 10 300 cells/mm 3 . Contrast-enhanced computerized tomography (CE-CT) of the neck disclosed a right-sided submental 20 × 10-mm abscess with gas bubbles ( Fig. 1 A ). An intravenous antibiotic therapy with ampicillin/sulbactam (3 g, 3 times per day) and metronidazole (500 mg, 3 times per day) was instituted. Surgical neck exploration revealed boiled-like necrotic fascial tissues with a collection of purulent material. Open neck spaces were drained and copiously irrigated with saline. One suction drain was placed.
Although partial improvement of general conditions, 4 days later, a control CE-CT showed the persistence of deep neck abscess. A revision of surgical neck exploration was performed; neck spaces exploration revealed a clear fluid material that was collected. Two drains were placed and removed after 10 days ( Fig. 1 B). Intraoperatively taken cultures showed A baumannii growth.
A baumannii drug susceptibility testing showed resistance to piperacillin/tazobactam, cefoxitin, cefepime, meropenem, trimethoprim, ciprofloxacin, and amikacin. Colistimethate and tigecycline were active. The isolate strain was also analyzed within an epidemiologic surveillance ongoing in our hospital to monitor MDR organisms to assess a nosocomial acquisition of the infection. To this aim, a repetitive sequence-based polymerase chain reaction–based typing method was used, using primers and protocol as previously described . The isolate profile was compared with other 20 strains obtained from isolates recovered in the hospital in that period (previous 3 and subsequent one month). Four different profiles were identified, one as prominent (profile A, 18 isolates), the index case (B), and 2 others (C, D) as divergent. No isolate was obtained in our ward; in the respiratory ICU, one strain (C profile) was isolated 3 months before and one A profile immediately after the index case; however, both were not correlated.
In the light of A baumannii ‘s susceptibility to colistin and tigecycline, the previous antibiotic treatment was replaced by intravenous tigecycline (initially 100 mg, then 50 mg, twice per day). Contact isolation of the patient and oral cavity mucosa cleansing with chlorhexidine solution were instituted.
On the 30th postadmission day, considering that a control CE-CT ruled out the presence of deep neck abscess, the patient was transferred to the Department of Infectious and Tropical Diseases. The patient continued intravenous antibiotic treatment with tigecycline (50 mg, twice per day). The fever was solved in a 7-day period, and the patient was discharged in good general conditions. At last follow-up control in September 2008, the patient’s good general conditions were confirmed.
2
Case report
In June 2008, an 83-year-old female diabetic patient was transferred to our department because of right-sided submental swelling, odynophagia, and nightly fever with undulating trend from the Respiratory Intensive Care Unit (ICU) of Padova Hospital, Padova, Italy, where she had been admitted 12 days before for an exacerbation of chronic obstructive pulmonary disease. On physical examination, the patient showed a fluctuating right-sided submental 3-cm mass with red and hot overlying skin and intense pain at palpation. The superior airways were normal even if a 1-cm ulcerate lesion in the anterior floor of the mouth was present, probably because of dental prosthesis decubitus. At admission, the white blood cell count was 10 300 cells/mm 3 . Contrast-enhanced computerized tomography (CE-CT) of the neck disclosed a right-sided submental 20 × 10-mm abscess with gas bubbles ( Fig. 1 A ). An intravenous antibiotic therapy with ampicillin/sulbactam (3 g, 3 times per day) and metronidazole (500 mg, 3 times per day) was instituted. Surgical neck exploration revealed boiled-like necrotic fascial tissues with a collection of purulent material. Open neck spaces were drained and copiously irrigated with saline. One suction drain was placed.
