Mycobacterium abscessus (M. abscessus) is a common rapid growing mycobacterium associated with pulmonary infection in patients with chronic lung disease. Skin, soft tissue and disseminated infections are rare, occurring mostly in patients with underlying conditions [1]. We reported a case of urinary tract infection with M. abscessus in a young hypertensive female patient and discussed the therapeutic option for this case.

Patient

The case patient is a 22 years old female secretary hospitalized on April first 2014 for kidney failure discovered during a blood pressure assessment in a context of headache, nausea, vomiting, and tinnitus. At the time of admission, the blood pressure was 240/130 mmHg, tachycardia 113 beats/minute. There was no history of previous major illness. The clinical picture evoked malignant hypertension. The diagnosis was confirmed by the presence of exudates and hemorrhages in the eye fundus examination, and a concentric hypertrophic cardiomyopathy with kidney of normal size at ultrasounds exam.

Initial laboratory findings on hospital admission

Laboratory tests showed serum creatinine at 2397 μmol/l, urea 60.6 mmol/l, the hemoglobin level at 7.6 g/dl with normal platelet count, dyslipidemia with total cholesterol and triglycerides respectively at 266 mg/dl and 185 mg/dl. The urine sample showed hematuria (667000/ ml), leukocyturia (260000/ml). The culture was sterile for other bacteria but showed the presence of numerous acid-fast bacilli on Lowenstein Jensen solid medium and the BacTAlert 3D liquid medium after Ziehl- Nielsen staining. The patient was then treated for malignant hypertension and urogenital tuberculosis with angiotensinconverting enzyme inhibitors and calcium channel blockers. The antitubercular therapy adapted to renal function with rifampicin, isoniazid, pyrazinamide, and ethambutol was established. With the regression of symptoms, the patient was discharged on April 28^th 2014 after four weeks of hospitalization.

Clinical course

On May 5^th 2014, she was readmitted in emergency with fever, vomiting, abdominal pain, diarrhea, and tachycardia 100/min, arterial blood pressure 130/95 mmHg. Laboratory test was positive for Plasmodium falciparum. No bacteria were recovered from stool and blood cultures. On May 9^th, 2014, M. abscessus was identified by a reverse line probe hybridization assay (GenoType Mycobacterium CM; Hain Lifescience GmbH, Nehren, Germany). The antituberculous treatment is stopped and replaced with clarithromycin at the dose of 1 g/day. Treatment with clarithromycin was continued successfully with a favorable outcome and improvement in renal function (creatinine 398 μmol/l, hemoglobin 9.5 g/dl). The patient was discharged after four weeks of treatment. The urine sample collected on June 16^th 2014 was sterile for bacteria and acid fast bacilli.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis complex; however, other mycobacteria species are involved in human infections [2]. M. abscessus complex is one of the main nontuberculous mycobacteria (NTM) for humans. The localization is mainly pulmonary but disseminated infection can occur. Nosocomial transmissions related to medical procedures occur and can cause outbreak [3]. The risk of infection with M. abscessus in hospitals especially in our setting remains high because of the lack of individual and collective hygiene. These infections occur mainly in immunocompromised individuals. Our patient had a kidney failure but was tested negative to Human Immunodeficiency Virus (HIV). Urogenital TB is the second localization accounting for 27% of extra pulmonary cases. However, genitourinary infections caused by NTM are rarely reported [4]. CT Huang et al. [4] reported 15 cases of genitourinary infections caused by nontuberculous mycobacteria among which Mycobacterium avium complex was the most common (n=5, 33%), followed by M. abscessus and Mycobacterium fortuitum (n=2; 13% each). The clinical picture, usually a fever, abdominal pain, diarrhea was present in our case. The complex is differentiated into 3 subspecies: M. abscessus subsp. abscessus , M. abscessus subsp . massiliense, and M. abscessus subsp. bolletii . These subspecies are differentiated by the presence of erm (41) gene which confers inducible macrolide resistance [5]. In resource limited setting, the diagnosis of TB and other NTM is based on the direct microscopic examination of specimens after ziehl Neelsen or fluorescent staining. But the primary specimen is usually negative. Misdiagnosis of TB due to the presence of NTM led to inappropriate treatment of patients [6]. In our case the patient was empirically treated with antituberculous drugs based on the acid fast staining before the identification. New macrolides particularly azithromycin and clarithromycin dramatically changed the treatment outcome of many NTM. Clarithromycin have shown success in treatment against M. xenopi , M. marinum , M. haemophilum , M. genavense , M. chelonae , and M. abscessus [7]. However, resistance to clarithromycin are reported ranging from <15% to >70% depending on the subspecies involved. In case of resistance azithromycin can be associated to amikacin and one of the following: fluoroquinolone, imipenem, doxycycline, or linezolid [8]. The treatment of complicated M. abscessus complex infections usually involves initial combination of macrolides (clarithromycin or azithromycin) plus intravenous agents for at least 2 weeks to several months [5]. Unfortunately we could not differentiate this strain at subspecies level because M. abscessus subsp. massiliense was describe to have a better prognosis and improved treatment outcomes than M. abscessus subsp. abscessus [9].

NTM urinary tract infections are under reported. Clinician’s attention should be drawn to consider differential diagnosis particularly in patients with underlying conditions. This is to our knowledge the first observation of urinary infection with M. abscessus in Mali successfully treated with clarithromycin with correct tolerance. Despite the severity of the clinical picture in our case, the evolution was favorable with a dramatic improvement in renal function, as the serum creatinine decreased from 2397 μmol/l the 398 μmol/l without dialysis and the disappearance of macroscopic hematuria.

No conflict of interest declared.

Informed consent obtained for publication of the case report.

The laboratory tests in this case study were done with funding from the Centre d’Infectiologie Charles Mérieux-Mali and the Fondation Mérieux.