Successful treatment of Rhodococcus lung abscess and empyema thoracis in a heart transplant recipient.

Rhodococcosis is an uncommon cause of pulmonary infection in thoracic organ transplant recipients. We describe a heart transplant recipient diagnosed with Rhodococcus equi left upper lung abscess with empyema thoracis complicated by bacteremia. The patient was successfully treated with appropriate antibiotics, adequate surgical resection, and optimization of immunosuppressants.

A case report of the differential diagnosis of Cellulosimicrobium cellulans-infected endocarditis combined with intracranial infection by conventional blood culture and second-generation sequencing.

BACKGROUND: Cellulosimicrobium cellulans is a gram-positive filamentous bacterium found primarily in soil and sewage that rarely causes human infection, especially in previously healthy adults, but when it does, it often indicates a poor prognosis. CASE PRESENTATION: We report a case of endocarditis and intracranial infection caused by C. cellulans in a 52-year-old woman with normal immune function and no implants in vivo. The patient started with a febrile headache that progressed to impaired consciousness after 20 days, and she finally died after treatment with vancomycin combined with rifampicin. C. cellulans was isolated from her blood cultures for 3 consecutive days after her admission; however, there was only evidence of C. cellulans sequences for two samples in the second-generation sequencing data generated from her peripheral blood, which were ignored by the technicians. No C. cellulans bands were detected in her cerebrospinal fluid by second-generation sequencing. CONCLUSIONS: Second-generation sequencing seems to have limitations for certain specific strains of bacteria.

Soft tissue infection caused by Mycolicibacter kumamotonensis.

Mycolicibacter kumamotonensis (M. kumamotonensis), formerly Mycobacterium kumamotonense, is a nontuberculous mycobacteria species, which was first separated from Mycobacterium terrae complex in 2006. Reports about infections caused by M. kumamotonensis are extremely rare, with most of them being lung infection. Here, we report the case of a 68-year-old man with a hobby of gardening who developed swelling in his right middle finger. He underwent surgical debridement at a previous hospital and was diagnosed with nontuberculous mycobacteria infection based on positive findings of acid-fast staining of pus obtained from the surgical specimen. He was treated with rifampicin, ethambutol, and clarithromycin, but the swelling worsened. Therefore, he was referred to our hospital for further examination and treatment. We performed a second debridement and added isoniazid to the treatment regimen, but the swelling continued to worsen. We then administered levofloxacin, but his condition did not change. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry and DNA sequencing analysis confirmed M. kumamotonensis as the causative bacterium. Since the finger swelling did not improve, the patient underwent a third debridement and amikacin was added to the treatment regimen. Finally, the infection was controlled. He completed amikacin therapy and will continue treatment with the other five antibiotics for a total of 24 months. To the best of our knowledge, this is the first report of a patient with M. kumamotonensis soft tissue infection. We consider this case might provide important insights into the diagnosis and treatment of soft tissue infections caused by M. kumamotonensis.

Half of 'Micrococcus spp.' cases identified by conventional methods are revealed as other life-threatening bacteria with different drug susceptibility patterns by 16S ribosomal RNA gene sequencing.

Bacterial infection during chemotherapy is a fatal complication, therefore precise identification of the pathogenic microorganism is required for treatment. We report that 2 of 4 pediatric patients with malignancy who were diagnosed with Micrococcus spp. infection by conventional methods were finally revealed to have Kytococcus schroeteri and Kocuria marina infection by 16S ribosomal RNA gene sequence analysis (16S rRNA analysis). Although K. schroeteri is morphologically similar to Micrococcus spp., its drug susceptibility profile is quite different from that of Micrococcus spp. K. schroeteri is resistant to penicillin and cephalosporin, which are effective for Micrococcus spp. In fact, penicillin-resistant lethal pneumonia caused by K. schroeteri has been reported in compromised hosts. Based on our results, Micrococcus spp. determined by conventional methods could contain other life-threatening bacteria with different drug susceptibility patterns from Micrococcus spp. To develop an effective empirical treatment for immunocompromised hosts, accumulation of pathogen data by 16S rRNA analysis is required.

Clinical and Biological Features of Cutibacterium (Formerly Propionibacterium) avidum, an Underrecognized Microorganism.

The recent description of the genus Cutibacterium has altered the taxonomy of Propionibacterium species. These organisms still belong to the genera of the skin coryneform group, and the most-studied species remains Cutibacterium acnes. Cutibacterium avidum is also a known skin commensal. This underrecognized microorganism can, however, act as a pathogen after bacterial seeding and can be considered opportunistic, causing either superficial or deep/invasive infections. It can cause numerous infections, including but not limited to breast infections, skin abscesses, infective endocarditis, and device-related infections. The ecological niche of C. avidum is clearly different from that of other members of the genus: it is found in the axillary region or at wet sites rather than in dry, exposed areas, and the number of microorganisms increases during puberty. Historically, it has been used for its ability to modulate the immune response and for its antitumor properties. Conventional microbial culture methods and identification processes allow for its accurate identification and characterization. Thanks to the modern omics tools used for phylogenomic approaches, understanding C. avidum pathogenesis (including host-bacterium interactions and virulence factor characterization) is becoming easier, allowing for more thorough molecular characterization. These analyses have revealed that C. avidum causes diverse diseases mediated by multiple virulence factors. The recent genome approach has revealed specific genomic regions within this species that are involved in adherence and biofilm formation as well as fitness, survival, and defense functions. Numerous regions show the presence of phages and horizontal gene transfer. C. avidum remains highly sensitive to a broad spectrum of antibiotics, such as ß-lactams, fluoroquinolones, macrolides, and rifampin, although erythromycin and clindamycin resistance has been described. A long-term treatment regimen with a combination of antibiotics is required to successfully eliminate the remaining adherent bacteria, particularly in the case of deep infections after debridement surgery.

Bacteremia and sepsis by Arcanobacterium haemolyticum in a young immunocompetent patient.

We report the case of a twenty-year-old immunocompetent male patient presenting to the emergency room with pharyngitis and fever. Blood cultures were drawn and Arcanobacterium haemolyticum (rough biotype) was recovered. The presence of the arcanolysin gene was investigated at the molecular level and the upstream region was amplified and sequenced in order to correlate it with the smooth or rough biotype. Although the isolate was susceptible to penicillin, vancomycin and gentamicin, empirical treatments first with amoxicillin/clavulanic acid (1g/12h) and then with ceftriaxone (1g/12h) failed and the infection evolved to sepsis. Finally, treatment with vancomycin (1g/12h) plus piperacillin/tazobactam (4.5g/8h) was effective. Lemierre's syndrome was ruled out. To the best of our knowledge, this is the first case of bacteremia by A. haemolyticum reported in Argentina.

Paradoxical worsening of chest radiographs secondary to immune reconstitution syndrome (IRIS) in a patient with advanced HIV infection and Rhodococcus pneumonia.

We present a rare case of post-antiretroviral therapy (ART) paradoxically worsening of radiological findings in a patient with advanced HIV-infection on treatment for Rhodococcus pneumonia who was misdiagnosed with pulmonary tuberculosis. Despite clinical improvement, serial chest radiographs showed deteriorations a month after starting ART. This was attributed to Immune Reconstitution Inflammatory Syndrome (IRIS) which spontaneously resolved without any treatment.

Rhodococcus equi pVAPN type causing pneumonia in a dog coinfected with canine morbillivirus (distemper virus) and Toxoplasma gondii.

Canine morbillivirus (previously, canine distemper virus, CDV) is a highly contagious infectious disease-causing agent that produces immunosuppressive infections and multiple clinical signs. Canine toxoplasmosis is an opportunistic disease characterized by enteric, pulmonary, and neuromuscular signs that might be confused with CDV-induced infections. Rhodococcus equi is a Gram-positive intracellular facultative bacterium that is also opportunistic in nature, and causes pyogranulomatous infections in humans and multiple host animals, although canine rhodococcosis is rare or unrecognized. The pathogenicity of R. equi is intimately related to the presence of plasmid-encoded virulence-associated proteins (Vap). Three host-adapted virulence plasmid types of R. equi have been recognized: the circular pVAPA and pVAPB are associated with equine and porcine strains, respectively, and the recently detected linear pVAPN virulence plasmid is related to bovine isolates. Nevertheless, data regarding the detection of host-adapted virulence plasmid types of R. equi isolated from companion animals are scarce. This report describes a case of an uncommon coinfection due to R. equi, T. gondii and CDV, which was diagnosed in a pet dog with respiratory distress. In this case, CDV most likely induced immunosuppression, which facilitated opportunistic infections by R. equi and T. gondii. The analysis of the virulence profile of R. equi revealed the novel pVAPN plasmid type, initially related to bovine strains. This is the second report of the bovine-associated pVAPN type in a pet dog, with an unusual coinfection with T. gondii and CDV. These findings represent a public health concern due to the close contact between pet animals and their owners, particularly because the pVAPN plasmid type was recently detected in people with HIV/AIDS from the same geographical region.

Brevibacterium paucivorans bacteremia: case report and review of the literature.

BACKGROUND: Brevibacteria are obligate aerobic gram-positive rods that are associated with milk products and are also found on human skin. Brevibacterium has been reported as a rare cause of catheter related blood steam infection mainly in immunocompromised hosts such as malignancies or AIDS patients. CASE PRESENTATION: A 94-year old woman, which had a past history of diabetes mellitus and chronic heart failure, presented with high fever associated with decreased oral intake and appetite loss and was admitted to our institute. A physical examination at the time of presentation was unremarkable. On day 2, both blood cultures collected on admission became positive with coryneform organism within 24 h without Staphylococci and Brevibacterium species were identified by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Subsequently, genetic investigation by 16S ribosomal RNA analysis was performed in order to identify the organism. Finally, the result identified this pathogen as Brevibacterium paucivorans with 99.5% homology on the Ez taxon database. The patient was started empirically on meropenem and teicoplanin for broad-spectrum antibiotic coverage. The patient's fever finally abated and labs were also improved. On day 14, the antibiotic therapy was discontinued. The site of infections was unknown. We hereby report a case of Brevibacterium paicivorans bacteremia in an immunocompetent patient and review cases of Brevibacterium specises bacteremia previously reported. This is the first case of B. paucivorans bacteremia as far as we could search. CONCLUSION: Physicians and microbiologists should be aware that Brevibacteria are uncommon but important agents which could cause opportunistic infections in immunocompetent.

Infections due to Cellulosimicrobium species: case report and literature review.

BACKGROUND: Cellulosimicrobium species, formely known as Oerskovia species, are gram-positive bacilli belonging to the order Actinomycetales. They rarely cause human infections. The genus comprises two pathogenic species in humans: C. cellulans and C. funkei. Based on a case report, we provide a review of the literature of infections caused by Cellulosimicrobium/Oerskovia, in order to improve our knowledge of this unusual infection. CASE PRESENTATION: An 82-year-old woman with aortic prosthetic valve presented to the hospital with fever and heart failure. Further work up revealed the diagnosis of C. cellulans infective endocarditis (IE). The strain was identified by MALDI-TOF MS, API Coryne and 16S rRNA sequencing. The patient was deemed not to be an operative candidate and died despite the antibiotic therapy 35 days after admission. CONCLUSIONS: Reviewing cases of Cellulosimicrobium species infections and communicating the successful and unsuccessful clinical experiences can assist future healthcare providers. Our case and those previously reported indicate that Cellulosimicrobium species usually infect immunocompromised patients or foreign body carriers. The most frequent pattern of infection is central venous catheter related bacteremia. The optimal treatment should include foreign body removal and valve surgery should be considered in case of IE.

Rhodococcus induced false-positive galactomannan (GM), a biomarker of fungal presentation, in patients with peritoneal dialysis: case reports.

BACKGROUND: Galactomannan index (GMI) at a level higher than 0.5 provides high sensitivity and specificity for the diagnosis of fungal peritonitis. Here, we report the false-positive of GMI in peritoneal dialysis (PD) effluent (PDE) due to Rhodococcus peritonitis in PD patients. CASE PRESENTATION: GMI in PDE of case #1 and case #2 were 1.53 and 0.76, respectively, while serum GMI of both cases was less than 0.5. In addition, GMI from the specimens obtained directly from the stationary phase of Rhodococcus colonies were 1.27 and 1.56, which were isolated from case #1 and #2, accordingly. CONCLUSION: High GMI in PDE of PD patients is not specific just for fungal infections but may also be secondary to other infections, such as Rhodococcus spp., especially in endemic areas.

Skin and soft tissue infection caused by Cutibacterium (formerly Propionibacterium) avidum: Report of eleven cases.

We describe the characteristics of 11 cases of skin and soft tissue infections due to Cutibacterium (formerly Propionibacterium) avidum. This microorganism should be considered a potential skin pathogen especially in patients with breast infections. The clinical outcome is usually good but serious infections such as necrotizing infections may occur.

The first reported case of pelvic inflammatory disease caused by Actinobaculum massiliense.

We report the first case of pelvic inflammatory disease (PID) caused by Actinobaculum massiliense. A 53-year-old woman attended the emergency department with symptoms compatible with a PID episode, finally resolved by intramuscular antibiotic treatment. Actinobaculum sp. was isolated by culture, and A. massiliense was confirmed by matrix assisted laser desorption time-of-flight mass spectrometry and 16S rRNA gene sequencing. Only a few cases of A. massiliense infections have been reported, and the pathogenesis of infections by these bacteria is poorly understood. The introduction of new diagnostic methods into hospital routines will improve the detection of new and little-studied pathogens.

First case of a bloodstream infection caused by the genus Brachybacterium.

An 83-year-old previously self-sufficient man was referred to our hospital for a fever, severe tenderness over the lumbar spine, and elevated C-reactive protein levels. Computed tomography revealed fluid collection in the intervertebral space of L3/4. Gram-positive, short rod-shaped bacteria were isolated from two sets of blood cultures. A 16S rRNA sequence analysis of an isolate showed a similarity of 98.1% to the nearest type strain Brachybacterium squillarum JCM 16464T. Biochemical characteristics of the presently isolated strain differed from those of the most closely related species of the genus Brachybacterium. The patient was successfully discharged on day 73 of admission with antimicrobial therapies and showed no recurrence during outpatient visits. Brachybacterium spp. have mainly been isolated from the environment, and human Brachybacterium infections have rarely been documented to date. To our knowledge, this is the first clinical isolation of Brachybacterium sp. as a causative pathogen of bloodstream infection.

INTERDIGITAL NECROBACILLOSIS ASSOCIATED WITH TRUEPERELLA PYOGENES IN GOITERED GAZELLES ( GAZELLA SUBGUTTUROSA).

This study presents the clinical findings, treatment results, and gross pathology of Trueperella pyogenes-associated interdigital necrobacillosis in captive goitered gazelles ( Gazella subgutturosa). Four male and two female gazelles presented with weight loss, front limb swelling, and persistent lameness despite antibiotic treatment. The animals were reluctant to bear weight on the affected limbs, and the diagnosis of interdigital necrobacillosis was made based on physical exam, bacteriologic evaluation, and radiographic imaging. In all cases, the interdigital skin and subcutaneous tissues were affected in both forelimbs. Exungulation (loss of the hoof) occurred in one female gazelle. Despite aggressive topical and systemic treatment, the two female gazelles died. Gross pathology detected abscesses in the heart, lung, and liver. T. pyogenes was isolated as the major pathogen. This is the first report of interdigital necrobacillosis caused by T. pyogenes in Gazella subgutturosa.

Thrombotic thrombocytopenic purpura-like syndrome associated with arcanobacterium pyogenes endocarditis in a post-transplant patient: A case report.

Systemic Arcanobacterium pyogenes is a rare bacterial infection in humans.1The diagnosis of thrombotic thrombocytopenic purpura (TTP)-like syndrome and infective endocarditis (IE) is often elusive. We report a case of TTP-like syndrome associated with A. pyogenes endocarditis in a post-allogenic transplant patient.

Peripherally inserted central catheter-related bloodstream infection caused by Kocuria marina in an elderly man.

BACKGROUND: Kocuria species are Gram-positive, aerobic cocci, and members of the Micrcoccaceae family that are known to be opportunistic pathogens. Although there have been sporadic reports of infections caused by Kocuria species, little is known regarding their human pathogenicity and clinical characteristics. CASE REPORT: We herein report a case of a peripherally inserted central catheter (PICC)-related bloodstream infection caused by Kocuria marina in a 90-year-old Japanese with multiple cancer. The patient, who was admitted due to adhesive intestinal obstruction, suddenly developed sepsis on day 29 following admission. Three sets of blood cultures and a culture of the PICC tip revealed the growth of Gram-positive cocci arranged in clusters. The patient improved quickly after treatment with an antimicrobial agent and catheter removal. The organism was identified as Kocuria varians using the MicroScan Walkaway system and K. varians/Kocuria rosea with a 99.7% probability using an API Staph system. However, 16S rRNA gene sequencing analysis identified the pathogen as K. marina. CONCLUSION: Although K. marina is a rare pathogen, physicians should consider it in case of catheter-related infections in patients with serious underlying conditions. As commercial identification systems can misidentify species within the Kocuria genus, the use of genomic methods such as 16S rRNA sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry may be useful for the precise identification of Kocuria to the species level.

A Chinese patient with peritoneal dialysis-related peritonitis caused by Gordonia terrae: a case report.

BACKGROUND: Gordonia terrae is a rare cause of clinical infections, with only 23 reported cases. We report the first case of peritoneal dialysis-related peritonitis caused by Gordonia terrae in mainland China. CASE PRESENTATION: A 52-year-old man developed peritoneal dialysis-related peritonitis and received preliminary antibiotic treatment. After claiming that his symptoms had been resolved, the patient insisted on being discharged (despite our recommendations) and did not receive continued treatment after leaving the hospital. A telephone follow-up with the patient's relatives revealed that the patient died 3 months later. Routine testing did not identify the bacterial strain responsible for the infection, although matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified the strain as Gordonia rubropertincta. However, a 16S rRNA sequence analysis using an isolate from the peritoneal fluid culture revealed that the responsible strain was actually Gordonia terrae. Similar to this case, all previously reported cases have involved a delayed diagnosis and initial treatment failure, and the definitive diagnosis required a 16S rRNA sequence analysis. Changes from an inappropriate antibiotic therapy to an appropriate one have relied on microbiological testing and were performed 7-32 days after the initial treatment. CONCLUSIONS: The findings from our case and the previously reported cases indicate that peritoneal dialysis-related peritonitis caused by Gordonia terrae can be difficult to identify and treat. It may be especially challenging to diagnose these cases in countries with limited diagnostic resources.

First identification of Gordonia sputi in a post-traumatic endophthalmitis patient - a case report and literatures review.

BACKGROUND: We present a case of post-traumatic endophthalmitis with relatively good prognosis caused by Gordonia sputi, which, to our knowledge is the first case in the literature. CASE PRESENTATION: A 24 year old man, who underwent an intraocular foreign body extraction half a month before presentation in the left eye, was referred to us complaining of blurred vision and slight pain for 5 days. His first presentation showed moderate intracameral and intravitreous purulent inflammation with a best corrected vision of counting fingers. After gram staining of the intravitreous samples revealed a gram-positive bacilli infection, a combination of amikacin and vancomycin was initially injected intravitreously. The left eye kept stable for three days but deteriorated on the 4th day. On the 5th day after presentation conventional culture characterized the bacterium as an Actinomyces sp. while 16S ribosomal RNA gene sequencing confirmed it as Gordonia sputi. Thereby a complete pars plana vitrectomy combined with lensectomy and silicone oil tamponade was performed. During the surgery an intraocular irrigation with penicillin G was adopted, followed by administration of intravenous penicillin G twice one day for a week. A relatively normal fundus with slight intracameral inflammation was observed a week after the operation, and the best corrected vision recovered to 0.15. One year later his vision remained 0.1. CONCLUSION: Gordonia sputi should be taken into consideration in patients with post-traumatic endophthalmitis especially due to foreign body penetration. Compared to conventional laboratories, molecular methods are recommended for an accurate diagnosis. A comprehensive strategy of antimicrobial agents and vitrectomy may render a satisfactory result.

Clinicopathologic correlation: mixed-density lesion in the posterior mandible.

A middle-aged man presented for evaluation of a mixed-density lesion of the left posterior mandible. This clinicopathologic correlation presents the radiographic, clinical, and histopathologic findings; differential diagnosis; and treatment plan for this case. The lesion was deemed to be of bacteriologic origin, likely a polymicrobial infection containing actinomycetes. Clinical care and follow-up for the patient are discussed.