Broviac catheter-related bacteraemias due to unusual pathogens in children with cancer: case reports with literature review

Delftia acidovorans: An Unusual Pathogen from an Adenocarcinoma Lung Patient with Pleural Effusion

Delftia acidovorans (D. acidovorans) is an aerobic, nonfermentative Gram-negative bacillus infrequently isolated from clinical specimens. The pathogenicity and clinical significance of the organism has not been ascertained due to uncommon clinical isolation and suspected low virulence. The organism has been reported to be inherently resistant to aminoglycoside group of drugs which remain as a widely used first-line drug of choice for febrile neutropenic patients. Hereby, we report a case of D. acidovorans-associated pleural effusion in a patient of metastatic adenocarcinoma diagnosed and treated timely and successfully with appropriate antibiotics.

Bombyx mori as a model for Niallia circulans pathogenicity

Increasing incidences of resistance to antibiotics by pathogenic bacteria is a worldwide concern and isolation of antibiotic-resistant strains of Niallia circulans (formerly known as Bacillus circulans), an opportunistic human pathogen, has been reported. Due to their lack of ethical constraints as well as their cost-effective rearing, invertebrates have been commonly used to study infection by bacteria pathogenic to humans. In this study, we demonstrate that a foodborne strain of N. circulans kills larvae of the silkworm, Bombyx mori within 48 h after hemolymph injection. The infected larvae turned black with an increase in the phenoloxidase (PO) activity in the hemolymph. Midgut injection of N. circulans resulted in the killing of larvae within 96 h. A significant increase in bacterial load was observed in the hemolymph 12 h after infection. The viable hemocyte number decreased to 48% within 12 h of injection. RT-qPCR analysis revealed that upon hemolymph infection with N. circulans the expression of the antimicrobial peptide (AMP) genes, Bmdefensin-B and Bmgloverin-3, were upregulated 2.5- and 1.8-fold, respectively, whereas 1.6-fold upregulation was observed for BmToll-2 in the larval fat body. Therapeutic effects of antibiotics like tetracycline, imipenem, ceftriaxone, ampicillin, and clindamycin were observed against N. circulans in the Bombyx larvae with varying efficacies. Results from this study suggest that larvae of B. mori can be used as infection models for screening therapeutics that are effective against N. circulans.

Brevibacterium Bacteremia in the Setting of Pyogenic Liver Abscess: A Case Report with Accompanying Literature Review

A 71-year-old Pakistani man with poorly controlled type 2 diabetes mellitus presenting with worsening mental status, abdominal pain, and oral intake for the past seven days was found to have pyogenic hepatic abscess with unculturable bacteria and subsequently found to have rare Brevibacterium bacteremia.

A Catheter-Related Bloodstream Infection by Brevibacterium casei in a Child with Acute Myeloid Leukemia: Case Report and Literature Review

The most common organisms isolated from pediatric catheter-related bloodstream infections (CRBSIs) are Gram-positive cocci, such as coagulase-negative staphylococci and Staphylococcus aureus. There are few formal reports of Brevibacterium casei infection and even fewer reports of CRBSI due to this Gram-positive rod. Here we report the first case of CRBSI due to B. casei in an 8-year-old girl with acute myeloid leukemia in Japan. The isolate exhibited decreased susceptibility to ß-lactam antibiotics. Antimicrobial therapy with meropenem and vancomycin, in addition to the removal of central venous catheter line, consequently led to a significant clinical improvement of the patient's symptoms. A literature review found available clinical courses in 16 cases (4 pediatric cases including our case) of B. casei infection. Our case and those in literature suggested that B. casei infection often occurs in patients with indwelling central venous catheters; the literature review further suggested that removal of central venous catheters is required in most cases. Special attention should be paid to the detection of opportunistic infections due to Brevibacterium spp. in immunocompromized children who are using a central venous catheter.

First report of spondylodiscitis caused by Bacillus circulans in an immunocompetent patient: Clinical case and review of the literature

Bacillus circulans is mainly considered an opportunistic pathogen in immunocompromised patients. However, many different infections have been described in the literature: bacteremia, abscesses, meningitis, endophthalmitis, and wound infections. We observed a spondylodiscitis caused by Bacillus circulans in an immunocompetent patient. To date, this is the first case reported in literature. Vertebral osteomyelitis represents for clinicians a challenging infection to manage and treat, because of its insidious and indolent course. The diagnosis is frequently difficult and can often be delayed for several months and initially be misdiagnosed and mismanaged. For this reason, the clinical case was described and all published cases of infection caused by Bacillus circulans were reviewed.

Brevibacteria tibial osteomyelitis

Brevibacteria are Gram-positive rods found in human skin flora and dairy products. Although generally not considered human pathogens, case reports have implicated Brevibacterium species as rare causes of bacteremia, endocarditis, peritonitis, and osteomyelitis. We report a case of Brevibacterium tibial osteomyelitis in an immunocompetent individual with implanted hardware and highlight the challenge of identifying the organism and recognizing it as a potential pathogen.

Catheter-related Brevibacterium casei bloodstream infection in a child with aplastic anaemia

Brevibacteria are a part of the normal skin flora and may be dismissed in blood cultures as contaminants. They have been reported as opportunistic pathogens in immunocompromised patients. We report a catheter-related bloodstream infection with Brevibacterium casei in a 6-year-old child with aplastic anaemia. Treatment with appropriate antibiotics along with the removal of the catheter resulted in complete cure in our patient.

Draft whole-genome sequence of Brevibacterium casei strain isolated from a bloodstream infection

Despite its low virulence potential and a commensal lifestyle as a member of the human skin microbiota, Brevibacterium casei has been increasingly reported as an opportunistic pathogen, especially in immunocompromised patients. Here, we present the draft genome sequence of the S51 strain isolated from a bloodstream infection. To the best of the authors’ knowledge, this is the first report of the draft genome sequence of the B. casei strain isolated from the clinical infection. The strain was identified using phenotypic and molecular methods and subsequently sequenced using the next-generation sequencing. The draft whole genome was assembled de novo, automatically annotated by Rapid Annotations using Subsystems Technology (RAST) server and scrutinized to predict the presence of virulence, resistance, and stress response proteins. The genome size of the S51 strain was 3,743,532 bp and an average G+C content was 68.3%. The predicted genes included 48 genes involved in resistance to antibiotics (including vancomycin, fluoroquinolones, and beta-lactams) and toxic compounds (heavy metals), 16 genes involved in invasion and intracellular resistance (Mycobacterium virulence operons), and 94 genes involved in stress response (osmotic, oxidative stress, cold and heat shock). ResFinder has indicated the presence of a beta-lactamase, and a phenotypic analysis showed resistance to penicillin. This whole-genome NGS project for the S51strain has been deposited at EMBL/GenBank under the accession no. QNGF00000000.

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.

The first reported catheter-related Brevibacterium casei bloodstream infection in a child with acute leukemia and review of the literature

Brevibacterium spp. are catalase-positive, non-spore-forming, non motile, aerobic Gram-positive rods that were considered apathogenic until a few reports of infections in immunocompromised patients had been published. To the best of our knowledge, this is the first report of B. casei catheter-related bloodstream infection in a child with acute leukemia. We aim to enhance the awareness of pediatric hematology and infectious disease specialists about this pathogen and review of the literature.

Investigation of Increased Rates of Isolation ofBacillusSpecies

Background.

In 2007–2008, several US hospitals reported summertime increases in the number of clinical blood cultures positive forBacillusspecies, which are common environmental bacteria.

Objective.

To investigate increased rates of isolation ofBacillusspecies from blood cultures, identify risk factors, and recommend control strategies.

Design.

Survey and case-control study.

Setting.

Multiple hospitals, including a cancer center.

Methods.

We surveyed 24 facilities that reported increases. We also conducted a field investigation at a hospital with a high rate, reviewing charts, collecting clinical and environmental isolates, and observing infection control procedures. A case-control study compared inpatient case patients who had any blood culture positive forBacilluswith unmatched control patients who had a blood culture with no growth during June-August 2008.

Results.

Among surveyed facilities, mean monthly rates rose from 25 to a peak of 75Bacillus-positive blood cultures per 10,000 blood cultures performed during the period June-August. At the hospital where the case-control investigation was conducted, for most case patients (75%), theBacillus-positive blood cultures represented contamination or device colonization rather than infection. We enrolled 48 case patients and 48 control patients; in multivariate analysis, only central venous access device use was significantly associated with case status (odds ratio, 14.0;P< .01). Laboratory testing identified at least 12 differentBacillusspecies (non-anthracis) among the isolates. Observation of infection control procedures revealed variability in central line care and blood sample collection techniques.

Conclusions.

Periodic increases in the environmental load ofBacillusspecies may occur in hospitals. Our investigation indicated that at one facility, these increases likely represented a pseudo-outbreak ofBacillusspecies colonizing central venous lines or their accessories, such as needleless connector devices. Vigilant attention should be paid to infection control practices when collecting blood samples for culture, to minimize the risk of contamination by environmental microorganisms.

Uncommon aetiological agents of catheter-related bloodstream infections

The clinical and microbiological characteristics of catheter-related bloodstream infection (CR-BSI) due to uncommon microorganisms was assessed in a retrospective case-control study over a 9-year period in a tertiary teaching hospital. Uncommon microorganisms were defined as those representing <0·5% of all CR-BSI. Diagnosis of CR-BSI required that the same microorganism was grown from at least one peripheral venous blood culture and a catheter tip culture. Thirty-one episodes of CR-BSI were identified due to 13 different genera and these accounted for 2·3% of all CR-BSI in the hospital. Although these infections were not associated with increased mortality, they occurred in patients with more severe underlying conditions who were receiving prolonged antibiotic therapy.

Intra-abdominal infections due to Comamonas kerstersii

Herein, we report four cases of Comamonas kerstersii intra-abdominal infections representing the first report of human infections caused by this Comamonas species. In addition, our work demonstrates the association of C. kerstersii with peritonitis secondary to appendix rupture.

Description of Acidovorax wautersii sp. nov. to accommodate clinical isolates and an environmental isolate, most closely related to Acidovorax avenae

Three Gram-negative strains, NF 1078(T), NF 1598 and NF 1715, were isolated from clinical (two) and environmental (one) samples, respectively. Sequence analysis of the 16S rRNA genes revealed similarity of 100% among the three strains and next highest similarity to the type strain of Acidovorax avenae (98.16%). The three strains were able to acidify lactose and rhamnose on low peptone phenol red agar and to alkalinize citrate on Simmons' agar and were negative for nitrate reduction. The DNA G+C content of strain NF 1078(T) was 67.1 mol%. The level of DNA-DNA relatedness between this strain and the type strains of A. avenae (ATCC 19860(T), LMG 2117(T)) was 29%. Based on these phylogenetic, phenotypic and genotypic analyses, the three strains could be distinguished clearly from all other recognized Acidovorax species and should be classified as representatives of a novel species of the genus Acidovorax, for which the name Acidovorax wautersii sp. nov. is proposed. The type strain is NF 1078(T) (=LMG 26971(T)=CCUG 62584(T)).

Delftia acidovorans bacteremia caused by bacterial translocation after organophosphorus poisoning in an immunocompetent adult patient

A 46-year-old woman was transferred to our emergency unit because of impaired consciousness and respiratory failure with the history of excessive pesticide intake. The patient was hypersalivative and had bilateral pupillary miosis. Laboratory results showed markedly decreased cholinesterase. She was intubated and treated in the intensive care unit with the diagnosis of organophosphorus poisoning. The patient had persisted diarrhea, with a high fever and stomach tenderness on day 10. Whole-body contrast enhanced computed tomography revealed a swollen, enhanced small intestinal wall, and blood culture identified Delftia acidovorans. She was diagnosed as D. acidovorans bacteremia, probably caused by bacterial translocation based on the clinical presentation and the exclusion of other sources, and treated well with a total of 8 days of antibiotic therapy. So far as we know, this is the first case of D. acidovorans bacteremia that was presumably caused by bacterial translocation after organophosphorus poisoning in an immunocompetent adult patient.

Acute infective endocarditis caused by Delftia acidovorans, a rare pathogen complicating intravenous drug use

Gram-negative bacilli causing infective endocarditis (IE) is rare, even in intravenous drug users. This case report underscores several clinically important aspects of Delftia acidovorans IE: the organism's ability to cause rapid destruction of normal native valves and to cause embolic occlusion of large arteries and its resistance to all aminoglycosides.

Spore-forming Bacilli and Clostridia in human disease

Many Gram-positive spore-forming bacteria in the Firmicute phylum are important members of the human commensal microbiota, which, in rare cases, cause opportunistic infections. Other spore-formers, however, have evolved to become dedicated pathogens that can cause a striking variety of diseases. Despite variations in disease presentation, the etiologic agent is often the spore, with bacterially produced toxins playing a central role in the pathophysiology of infection. This review will focus on the specific diseases caused by spores of the Clostridia and Bacilli.

Agrobacterium radiobacter bacteremia in a child with acute lymphoblastic leukemia

BACKGROUND

Agrobacteria are Gram-negative tumorigenic plant pathogens that rarely cause infections in humans.

METHODS

The authors describe a 7-year-old boy with acute lymphoblastic leukemia who carried a central venous catheter and developed bacteremia due to Agrobacterium radiobacter (A. radiobacter).

RESULTS

Microbiological cure was achieved after administration of systemic ceftriaxone along with gentamicin lock therapy to the central venous catheter for 10 days. Catheter removal was not required, and the patient has not relapsed with bacteremia due to the same pathogen for more than 6 months.

CONCLUSIONS

A. radiobacter is an emerging pathogen affecting immunocompromised children, particularly those with leukemia who carry central venous catheters. Although it has a low virulence, erratic susceptibility patterns, and high frequency of resistance to many antibiotics, ceftriaxone appears to be successful in treatment of most cases. Catheter removal for the clearance of bloodstream infections due to A. radiobacter may not be required in selected patients like the present case.

Management of Bacillus bacteremia: the need for catheter removal

Bacillus species are biofilm-forming organisms that are associated with Bacillus catheter-related bloodstream infections (CRBSIs). The optimal treatment of Bacillus CRBSIs is not known. Therefore, in the current study, we determined the role of long-term central venous catheter (CVC) removal and treatment with vancomycin compared with other agents in Bacillus CRBSIs by retrospectively reviewing the medical records of cancer patients with Bacillus bacteremia who had been treated at our institution from December 1990 to March 2008. True bacteremia was defined as a positive blood culture (>15 colony-forming units/mL) with signs and symptoms of infection (such as fever and chills). Bacillus CRBSI was defined in accordance with the Infectious Diseases Society of America guidelines as probable or definite. There were 94 Bacillus bacteremia episodes, 93 of which (99%) were Bacillus CRBSIs (28% definite and 71% probable). Neutropenia during bacteremia occurred in 29%. Almost all bacteremia patients (99%) had been treated with antibiotics; 63% had received vancomycin. Sepsis with hypotension occurred in 6%, and endocarditis in 1%. Bacillus isolates were susceptible to linezolid (100%), vancomycin (98%), tetracycline (77%), and rifampin (67%). All 4 recurrences occurred in patients in whom the CVC had not been removed (12%), whereas no recurrences occurred in patients whose CVC had been removed (p = 0.028). Patient outcome, in terms of fever and hospitalization duration after the infection, was similar in patients who had received < or =10 days of systemic antibiotics compared with patients who had received >10 days. In conclusion, catheter retention in patients with Bacillus CRBSIs is associated with a significantly higher recurrence rate. If the CVC is retained, treatment with non-vancomycin antibiotics is associated with significantly shorter hospitalization duration after the infection, which may be because glycopeptide antibiotics have poor activity against bacilli embedded in biofilm.

Implanted-port-catheter-related sepsis caused by Acidovorax avenae and methicillin-sensitive Staphylococcus aureus

Acidovorax avenae is a gram-negative rod in the family Comamonadaceae and a phytopathogen found in the environment. Human infections caused by members of the Comamonadaceae are extremely rare. We report a case of implanted-port-catheter-related sepsis caused by Acidovorax avenae and methicillin (meticillin)-sensitive Staphylococcus aureus (MSSA).

Agrobacterium radiobacter bacteremia in oncologic and geriatric patients: presentation of two cases and review of the literature

INTRODUCTION

We report here two cases of Agrobacterium radiobacter bacteremia. These cases were observed at the same institution over a short time period (3 months).

CASE REPORTS

The first patient was a female cancer patient receiving third-line chemotherapy for ovarian carcinoma. When she developed bacteremia, she was neutropenic and had an indwelling catheter that was removed as part of the treatment. The second case was a geriatric patient admitted from home with bacteremia, clinical signs of septic shock, and concomitant acute cholecystitis.

OUTCOME

Both patients responded promptly and completely to antibiotherapy. No recurrence was observed.

Histopathology and genotyping in infectious spondylitis of HIV- and HIV+ patients

Approximately 2 million South Africans are HIV/TB coinfected, and many develop skeletal disease. The resurgence of spinal tuberculosis, including atypical forms, is due largely to HIV-associated immune suppression. We investigated the impact of HIV coinfection on the histological features of the disease and the occurrence of atypical opportunistic organisms in infectious spondylitis in an HIV/TB endemic region. We analyzed blood and tissue biopsies from 60 patients with tuberculous spondylitis. Investigations included full blood counts, CD4/CD8 counts, HIV-1 serology and RNA quantification (tissue and plasma), acid-fast bacilli localization and routine TB culture, histopathologic evaluation of biopsies, and bacterial genotyping using the 16S rDNA gene. Twenty-two patients (37%) were HIV positive with a mean age of 29 years (range, 2-65 years). Forty-one (68%) tissue specimens were culture negative for Mycobacterium tuberculosis (Mtb), although nontuberculous mycobacteria (NTM) were identified in three HIV-negative patients. Histopathologic features were characteristic of TB infection in 91.4% of all specimens tested and 100% of the HIV-infected group. Genotyping of 10 culture-positive isolates identified Mtb (3/10), NTMs (2/10), and environmental bacilli (3/10). Our observations suggest HIV-induced immune suppression impacts the histological and clinical features of infectious spondylitis but has no impact on the incidence of NTMs in this setting.

Management of long-term catheter-related Brevibacterium bacteraemia

Brevibacterium has been reported as a rare cause of implanted-device infection. In two cases of recurrent Brevibacterium casei bacteraemia associated with infection of surgically implanted intravascular devices, relapse occurred 2 and 5 months, respectively, after completion of therapy with vancomycin via the infected catheter. A second intravenous antibiotic therapy course by the antibiotic-lock technique led to bacteriological cure in one patient. Molecular typing results demonstrated that the recurrent bacteraemia was caused by the same strain. Implanted-device removal may be necessary, in addition to appropriate antibiotics, for successful management of such infections.

Six cases of Lactobacillus bacteraemia: identification of organisms and antibiotic susceptibility and therapy

Six cases of bacteraemia in hospitalized patients, 5 with a depressed immune status, were caused by lactobacilli. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and API 50 CH carbohydrate patterns assigned the causative agents to the species Lactobacillus rhamnosus, Lactobacillus curvatus, Lactobacillus delbrueckii subsp. lactis and Lactobacillus paracasei subsp. paracasei.

Bacteraemia and sinusitis due to Flavimonas oryzihabitans infection

Flavimonas oryzihabitans is rarely reported as a pathogen in human infections and is related to opportunistic infection. Previously reported cases of infections caused by this bacterium were nosocomially acquired, including bacteraemia in critically ill patients, catheter-related infection, and peritonitis in patients undergoing continuous ambulatory peritoneal dialysis. Three cases of F. oryzihabitans infection are presented, 1 of which was sinusitis and 2 were nosocomially acquired bacteraemia. To the authors' knowledge, this is the first reported case of sinusitis infection due to F. oryzihabitans induced by prosthetic material. Isolates from the 2 bacteraemic patients were susceptible to tazobactam, ceftazidime, cefepime, aztreonam, gentamicin, amikacin, imipenem, ciprofloxacin and levofloxacin, but resistant to cephazolin, cefuroxime and trimethoprim. The isolate from the sinus was susceptible to gentamicin, amikacin, tetracycline, ciprofloxacin and levofloxacin. After appropriate treatment all the patients recovered and no longer showed signs of the pathogen.

Occurrence of sessile Pseudomonas oryzihabitans from a karstified chalk aquifer

Pseudomonas oryzihabitans is an uncommon pathogen that may cause opportunistic infections. Although it has been previously isolated from the environment, the source of human infection has not been well documented. In this study, we describe the presence of P. oryzihabitans adhering on suspended particulate matters recovered from karst groundwaters. The isolated pathogen was capable of forming biofilms on silicon supports and clay beads. Adherent P. oryzihabitans cells displayed a high resistance to chlorine as compared with the same organisms cultured in the planktonic mode. These results demonstrate that aquifer biofilms are potential environmental sources for water-born P. oryzihabitans infections and that bacterial attachment might affect drinking water purification.

Agrobacterium radiobacter bacteremia in pediatric patients: case report and review

Agrobacterium radiobacter is an opportunistic pathogen often associated with indwelling catheters. We report five children with central venous catheter-associated A. radiobacter bacteremia and review the characteristics of pediatric Agrobacterium infections. Cure was achieved with appropriate antibiotics, often ticarcillin-clavulanate and gentamicin, and removal of the catheter.

Bacteraemia in a paediatric oncology unit in South Africa

OBJECTIVES

To identify the morbidity and mortality due to infections in a South African paediatric oncology unit, and to identify risk factors associated with first bacteraemic episodes in this unit.

PROCEDURE

A retrospective cohort study was done in a large regional referral paediatric cancer centre from 1991-1995, of all consecutive patients with culture proven bacteraemia. Eighty-three oncology patients were studied (median age 4.0 years) in whom a total of 200 episodes of bacteraemia were recorded, of which 83 first bacteraemic episodes.

RESULTS

Of the 200 episodes 70% were caused by Gram-positive organisms, 20% by Gram- negative organisms and 10% by fungal organisms. Organisms associated with high mortality were Gram-negative organisms (Acinetobacter spp., Pseudomonas aeruginosa, Klebsiella species), and fungal organisms, (Candida parapsilosis). Seventeen out of 200 episodes ended in death of the patient. In 59% of patients Hickman catheters were in situ. The mean incidence of catheter related bacteraemia's was 3.3 episodes per 1000 catheter days. Seventy percent of first bacteraemic episodes occurred within 50 days after placement of the catheter. The generalized estimation equations model revealed that more Gram-negative infections occurred in the presence of a Hickman catheter (odds ratio 2.2, 95% CI 1.0-5.0). The presence of neutropenia and the use of parenteral nutrition were not associated with specific bacteraemic patterns.

CONCLUSIONS

Including all bacteraemic episodes in this cohort study a high incidence of fungal infections occurred of which 64% occurred with a Hickman catheter in situ. Candida parapsilosis had a higher incidence than reported in other centres. Secondly looking at first bacteraemic episodes a high incidence of Gram-negative infections was observed especially in the presence of a Hickman catheter.

Bacillus sphaericus bacteraemia in children with cancer: case reports and literature review

In the period 1989-1999, Bacillus sphaericus was demonstrated to cause 12 out of 469 (2%) episodes of bacteraemia in children with cancer or receiving bone marrow transplant at G. Gaslini Children's Hospital, Genoa, Italy. Neutropenia was present in five episodes, six episodes, (all without neutropenia) were related to the presence of a central venous catheter, and one episode occurred in a patient with intestinal graft vs. host disease and gut colonization. All patients survived. Ciprofloxacin was the only drug active against all the isolated strains.Bacillus sphaericus represents a new cause of infection in the immunocompromised host, with low aggressiveness, but a peculiar pattern of antibiotic susceptibility.

Brevibacterium casei sepsis in an 18-year-old female with AIDS

Brevibacterium sp. was isolated from the blood of an acutely ill 18-year-old female with AIDS. The isolate was identified as Brevibacterium casei by use of carbohydrate assimilation tests. Treatment was successful with intravenously administered ciprofloxacin. To our knowledge, this is the first report of sepsis caused by B. casei in a human immunodeficiency virus-infected patient.

Agrobacterium yellow group: bacteremia and possible septic arthritis following peripheral blood stem cell transplantation

A 47-year-old male patient developed sepsis and monoarticular arthritis following autologous stem cell transplantation for recurrent Hodgkin's disease. Blood cultures were positive for Agrobacterium yellow group. The knee pain and swelling responded promptly to the institution of empirical broad-spectrum antibiotics. Recurrent bacteremia developed necessitating Hickman line removal for eventual resolution of the infection. Transplant physicians should be aware of this unusual pathogen and the potential for both persistent line-related sepsis and possible septic arthritis.

Prosthetic heart valve endocarditis caused by Bacillus circulans

We report a case of prosthetic valve endocarditis due to Bacillus circulans in a 56-year-old woman. Pre-operative blood cultures were negative and the organism was only recovered on culture of the explanted mechanical valve. We discuss the reasons for the late clinical presentation of this case, 15 months post valve replacement, caused by an organism which is conventionally regarded as 'early' pathogen. The patient recovered well post surgery on a 6 week course of trimethoprim and ciprofloxacin.

Comamonas acidovorans contamination of dental unit waters

A study was carried out to evaluate the extent of the colonization of dental water systems by Comamonas acidovorans and to investigate how the occurrence of these bacteria is related to certain water characteristics. The 152 water samples were collected from the oral rinsing cup, air-water syringe, turbine and supply lines to dental units. Comamonas acidovorans was found most frequently and in greatest quantities in samples taken from water entering the units and in samples with a lower total bacterial count at 22 degrees C, higher temperature, lower content of organic matter and, in general, higher concentrations of residual chlorine.

Unusual clinical presentation of infection due to Flavimonas oryzihabitans

Six cases of Flavimonas oryzihabitans infection are presented, four of which were community-acquired pneumonia and two of which were nosocomially acquired bacteremia. All four cases of pneumonia occurred in immunosuppressed hosts, three of whom were HIV-positive individuals and one of whom was a young man affected by chronic myeloid leukemia. Flavimonas oryzihabitans is recognized with increasing frequency as a cause of opportunistic infection, but the present cases of community-acquired pneumonia due to this organism are believed to be the first four reported in the English literature. The findings emphasize that Flavimonas oryzihabitans should be included in the list of pathogens that cause community-acquired infections in the immunocompromised host.