A 52-year-old woman treated with prednisone 12.5 mg daily, methotrexate 10 mg weekly, and hydroxychloroquine 200 mg daily for systemic lupus erythematosus (SLE), diagnosed 3 years earlier, with low-grade leuko-antiHSDNA, compatible with polyarthritis.
With an insidious onset, a month ago the patient presented with scarce cough, mucopurulent expectoration, pain in the right hemithorax with inspiratory cough, progressive dyspnea 10%, and weight loss.
She had no fever during this period.
She was initially treated with clarithromycin for 10 days, with no good response, and was hospitalized for study.
A CT scan of the chest showed bilateral atelectasis and a small right pleural effusion (not punctureable), with no consolidations or replacement images.
Given the association with polyarthralgia and positive SLE serology (anti-DNA Farr 975 U) the findings were interpreted in the context of a lupus activity and methotrexate 75 mg/zathioprine was switched.
During the following months, the patient remained afflicted, but occasionally with persistent cough and hemoptoic-purulent expectoration, receiving levofloxacin 500 mg/day for 10 days, which partially reduced the symptoms.
Despite the lack of risk factors for acquiring HIV infection, a serological study of HIV-1 and HIV-2 (ELISA) was performed with negative results.
At the seventh month of evolution, the patient was hospitalized again due to fever up to 38ยบ C. Chest CT showed this time focus of bilateral consolidation, mediastinal nodules, adenopathy and mediastinal consolidation.
Laboratory: PCR 20.1 mg/dL (VN < 1.0 mg/dL) and ESR 118 mm/h.
A fibrobronchoscopy showed proximal bronchial inflammation with deformation of the right apical segmental bronchus, where biopsy was obtained.
A microbiological study of bronchoalveolar lavage (BAL) was negative, including mycobacterial infections and cryptococcus jirove bacteria.
Bronchial biopsy showed fibrinolytic exudate with necrotic tissue.
Antimicrobial treatment with cefoxime +clindamycin was indicated and received for seven days under the diagnosis of cavitated pneumonia of unknown etiology.
Due to the good evolution, she was discharged to complete three weeks of treatment with amoxicillin/clavulanic acid, azathioprine was suspended and maintained with prednisone and hydroxychloroquine.
However, in the following weeks the symptoms worsened and the patient was hospitalized again.
Laboratory evaluation showed leukopenia with left shift, ESR 119 mm/h and CRP 35 mg/dL.
The chest X-ray showed an image consistent with abscess and CAT scan showed cavitated nodules and massive consolidations.
Sputum smear microscopy and Kin staining in expectoration were repeated, resulting negative.
A new fiberoptic bronchoscopy revealed sunken whitish lesions in the tracheal mucosa, obtaining biopsy for microbiological and histological studies.
A percutaneous lung biopsy was performed under CAT, whose histology revealed a large inflammatory process with the presence of Gram-positive bacilli intramacrific process.
The development of bacilli, diagnosed as Rhococcus grampositive, occurred both in the current culture of the tissue recovered by CT biopsy and in that obtained by fiberoptic bronchoscopy.
Gender identification was carried out in the Microbiology Laboratory of the UC Health Network using a Gram-negative rod-type (i.e., a non-conscious, continuous-aerobic acid - CHI) staining pattern.
The development of lamb blood agar plates showed coral mucoid colonies after two days of incubation.
With these tests the colon was sent to the Public Health Institute of Chile (Labortion of recurrence) with the presumptive diagnosis of Rhococcus spias, where the typical morphology of the macroscopic stain and Gram stain were confirmed.
Biochemical tests were performed in an API Coryne® (Biomerieux) gallery with the following results: negative negative negative acid nitrates, negative pyrazinamide (glucerase negative, negative acid glucoside reverse transcriptase), negative
Rhococcus equi was reported by these biochemical tests and by the macroscopic characteristics
Treatment was initiated with vancomycin 2 g/day and rifampicin 600 mg/day, with good initial response.
After 6 weeks of therapy she developed an intense pruritic rash requiring a change in her schedule.
To define the following antimicrobial therapy an in vitro susceptibility study was conducted by agar dilution and epsilo (E-test®).
Although the breakpoints of the antimicrobials for this microorganism are not described, MIC values > 32 μg/mL and ciprofloxacin, > 40 μg/mL were measured to gentamicin cotrimoxazole and < 2μg/mL.
With this information the scheme was changed to ciprofloxacin + amikacin and then ciprofloxacin + clarithromycin until 24 weeks of treatment.
The clinical evolution was favorable with slow and progressive decrease of symptoms until disappearing, decrease of inflammatory parameters in laboratory tests until normalization, and regression of the images of pulmonary consolidation in the CT scan of the chest.
