Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit

Achromobacter cluster related to COVID-19 supply chain issues

Isolation of an unusual organism, Achromobacter xylosoxidans, from 2 cardiac surgical patients on the same day prompted an investigation to search for cases and cause. An extensive review demonstrated a pseudo-outbreak related to practices to conserve laboratory saline due to short supply resulting from supply chain shortage from the coronavirus disease 2019 pandemic.

Achromobacter pneumonia in a patient with advanced COPD, a diagnostic challenge

Bacterial pneumonia causes significant morbidity and mortality especially in elderly and immunocompromised hosts. Achromobacter xylosoxidans denitrificans pneumonia is very rarely reported. However, the reported cases have been in patients who are either immunocompromised or have bronchiectasis. We hereby present a unique case of Achromobacter xylosoxidans denitrificans pneumonia in an immunocompetent patient with advanced chronic obstructive pulmonary disease (COPD). Our patient is a Caucasian male admitted with shortness of breath, fever and cough. Chest X-ray demonstrated right-sided infiltrates and he was treated with intravenous ceftriaxone and azithromycin. He was discharged home on oral amoxicillin-clavulanate 875-125 mg two times per day for a total of 7 days. Patient returned to emergency room after 5 weeks with persistent symptoms and chest X-ray revealed persistent right-sided infiltrate and sputum culture showed Achromobacter xylosoxidans denitrificans. The patient was started on oral levofloxacin 750 mg one time per day for 2 weeks with resolution of symptoms.

Outbreak and control of Achromobacter denitrificans at an academic hospital in Pretoria, South Africa

OBJECTIVE

In this study, we sought to determine the source of an outbreak of Achromobacter denitrificans infections in patients at a tertiary-care academic hospital.

DESIGN

Outbreak report study with intervention. The study period extended from February 2018 to December 2018.

SETTING

The study was conducted at a tertiary-care academic hospital in Pretoria, South Africa.

PATIENTS AND PARTICIPANTS

All patients who cultured A. denitrificans from any site were included in this study. During the study period, 43 patients met this criterion.

INTERVENTIONS

Once an outbreak was confirmed, the microbiology laboratory compiled a list of affected patients. A common agent, chlorhexidine-and-water solution, was used as a disinfectant-antiseptic for all affected patients. The laboratory proceeded to culture this solution. Environmental and surface swabs were also cultured from the hospital pharmacy area where this solution was prepared. Repetitive-element, sequence-based, polymerase chain reaction (rep-PCR) was performed on the initial clinical isolates to confirm the relatedness of the isolates.

RESULTS

In total, 43 isolates of A. denitrificans were cultured from patient specimens during the outbreak. The laboratory cultured A. denitrificans from all bottles of chlorhexidine-and-water solutions sampled from the wards and the pharmacy. The culture of the dispenser device used to prepare this solution also grew A. denitrificans. The rep-PCR confirmed the clonality of the clinical isolates with 2 genotypes dominating.

CONCLUSIONS

Contaminated chlorhexidine-and-water solutions prepared at the hospital pharmacy was determined to be the source of the outbreak. Once this item was removed from the hospital, the laboratory did not culture any further A. denitrificans isolates from patient specimens.

Study of post-opening stability of active ingredients in hand sanitizers

INTRODUCTION

Hand disinfection plays an important role in infection control. Currently, hand sanitizers containing ethanol and chlorhexidine gluconate as active ingredients are widely used. Most of hand sanitizers have a defined expiration date for use. However, there was no rule about the expiration date after opening defined with the evidence. Therefore, we examined the fluctuation of active ingredients and disinfection effect after opening the bottle.

METHOD

Twelve hand sanitizers from 44 to 921 days after opening set in different places in the hospital were examined and unopened hand sanitizer used as a control. Chlorhexidine gluconate and ethanol of each samples were measured by high performance liquid chromatography and gas chromatography, respectively. The correlation between the concentration of each ingredient obtained and the number of days after opening, bottle weight, storage temperature and humidity was analyzed. A time-kill test based on ASTM E2315-03 was performed to confirm the actual disinfection effect.

RESULTS

It was observed that active ingredients had not been decreased up to 921 days after opening and were not affected by storage conditions after opening. In addition, a decrease of disinfection effect was not observed in any sample.

CONCLUSIONS

We found that hand sanitizers do not need to be discard after a number of days have passed because the active ingredients are retained even after opening in it.

Recurrent environmental contamination in a centralized radiopharmacy unit by Achromobacter spp: results of a large microbiological investigation

BACKGROUND

Radiopharmaceuticals preparation unit, such as every aseptic preparation units, are strictly monitored in terms of microbiological contamination. Despite all biocontamination control procedures, our radiopharmacy unit faced repeated environnmental contamination by Achromobacter spp which necessitated a large environmental investigation.

METHOD

Microbiological controls were carried out using Count Tact agars (Biomérieux) for flat surfaces, dry swabbing for hard to reach areas and containers were filled with a sterile water solution (then filtrated on 0.45µm membrane and seeded). Microbiological identification was performed by mass spectrometry (MALDI-TOF-MS, Brucker) on each positive sample.

RESULTS

Achromobacter spp was found in 10% of the 413 samples during the 8 months investigation period. The proportion of positive samples was stable among time but their location was unpredictable. The highest inoculum was finally found in the buckets used for biocleaning.

DISCUSSION

Samples from cleaning buckets taken by dry swabbing were at first negative, but the use of a non-routinely used sampling method allowed to discover the reservoir of this persistent contamination.

CONCLUSION

This investigation alerted us on the high microbiological risk associated with reusable plastic containers and the importance of a sampling method adapted to critical locations.

Achromobacter xylosoxidans Bacteremia in a Liver Transplant Patient: A Case Report and Literature Review

Since the first isolation of Achromobacter xylosoxidans, it has been increasingly recognized as an opportunistic pathogen. It is an aerobic Gram-negative bacillus mainly found in aquatic environments. It has been reported to cause nosocomial infections, especially in immunocompromised patients. This organism has a unique susceptibility to antimicrobials, being resistant to most commonly used cephalosporins and aminoglycosides, with susceptibility to piperacillin/tazobactam and most carbapenems. In this case, we report a case of a 60-year-old female with a history of liver transplantation, who developed nosocomial Achromobacter xylosoxidans bacteremia complicated by septic shock, multi-organ failure, and death.

A multi-center outbreak of Candida tropicalis bloodstream infections associated with contaminated hemodialysis machine prime buckets

BACKGROUND

Outbreaks of fungal bloodstream infection (BSI) are uncommon among hemodialysis patients. We investigated an outbreak of Candida tropicalis BSIs involving patients at 3 of 4 affiliated hemodialysis units.

METHODS

An investigation included a review of records of patients with C tropicalis BSI, a case-control study, and cultures of medications, hands of personnel, dialysis equipment, and water samples.

RESULTS

Eight patients developed C tropicalis BSIs in a 3-month period. Compared to controls, cases had a higher proportion of preceding dialyses performed on a machine with a contaminated saline prime bucket (SPB) (P= .02). Observations revealed that SPBs at units A-C were rinsed with tap water, were not routinely disinfected, and that priming tubing was allowed to contact fluid in SPBs. C tropicalis was recovered from the main compartment and hollow handle of SPBs and from other environmental samples. C tropicalis isolates from patients, SPBs and other environmental samples had indistinguishable pulsed-field gel electrophoresis patterns. Following routine disinfection of SPBs, the outbreak terminated.

CONCLUSIONS

This outbreak was likely due to inadequate disinfection of SPBs. The findings emphasize the importance of disinfection of SPBs. Current use of identical SPBs warrants further evaluation of hollow SPB handles as a potential infection risk.

Saezia sanguinis gen. nov., sp. nov., a Betaproteobacteria member of order Burkholderiales, isolated from human blood

The taxonomic position of an unknown bacterial strain designated CNM695-12, isolated from the blood of an immunocompromised subject, was investigated via phenotypic, chemotaxonomic, genotypic and genomic analyses. Bacterial cells were determined to be Gram-stain-negative bacilli, aerobic, non-motile and non-spore-forming. The strain showed catalase activity but no oxidase activity. Optimal growth occurred at 37 °C, pH 7 and with 0-1 % NaCl. C_16 : 0, summed feature 8 (comprising C_18 : 1ω7c /C_18:1 ω6c), and C_18 : 1ω9c were the most abundant fatty acids, and ubiquinone 8 was the major respiratory quinone. The polar lipids present included phosphatidylglycerol, phosphatidylethanolamine and other aminophospholipids. The 16S rRNA gene sequence showed approximately 93.5 % similarity to those of different species with validly published names within the order Burkholderiales (e.g. Leptothrix mobilis Feox-1^T, Aquabacterium commune B8^T , Aquabacterium citratiphilum B4^T and Schlegelella thermodepolymerans K14^T). Phylogenetic analyses based on 16S rRNA gene sequences and concatenated alignments including the sequences for 107 essential proteins, revealed the strain to form a novel lineage close to members of the family Comamonadaceae. The highest average nucleotide identity and average amino acid identity values were obtained with Schlegelella thermodepolymerans K14^T (69.6 and 55.7 % respectively). The genome, with a size of 3.35 Mb, had a DNA G+C content of 52.4 mol% and encoded 3056 predicted genes, 3 rRNA, 1 transfer-messengerRNA and 51 tRNA. Strain CNM695-12 thus represents a novel species belonging to a novel genus within the order Burkholderiales, for which the name Saezia sanguinis gen. nov., sp. nov. is proposed. The type strain is CNM695-12^T (=DSM 104959^T=CECT 9208^T).

Hematogenous pleural infection caused by Achromobacter xylosoxidans in a patient undergoing maintenance hemodialysis

A 78-year-old Japanese man, undergoing maintenance hemodialysis for 20 years and having received coronary artery bypass grafting two months before, was hospitalized because of fever with subclinical left-sided pleurisy. Achromobacter xylosoxidans strains exhibiting identical genomic patterns on a macrorestriction analysis were isolated from the blood and the pleural effusion obtained on admission. Physical and radiological examinations did not reveal any lesions in either chest wall or lung adjacent to the effusion, indicating that the organism in the effusion had entered the pleural space via the bloodstream. Immunocompromising conditions due to undergoing maintenance hemodialysis and the presence of the antecedently accumulated pleural effusion may have been associated with the development of hematogenous dissemination. The patient fully recovered only with antibiotic therapy. To our knowledge, the present report is the first describing a case of hematogenous pleural infection caused by A. xylosoxidans.

Betaproteobacteria are predominant in drinking water: are there reasons for concern?

Betaproteobacteria include some of the most abundant and ubiquitous bacterial genera that can be found in drinking water, including mineral water. The combination of physiology and ecology traits place some Betaproteobacteria in the list of potential, yet sometimes neglected, opportunistic pathogens that can be transmitted by water or aqueous solutions. Indeed, some drinking water Betaproteobacteria with intrinsic and sometimes acquired antibiotic resistance, harbouring virulence factors and often found in biofilm structures, can persist after water disinfection and reach the consumer. This literature review summarises and discusses the current knowledge about the occurrence and implications of Betaproteobacteria in drinking water. Although the sparse knowledge on the ecology and physiology of Betaproteobacteria thriving in tap or bottled natural mineral/spring drinking water (DW) is an evidence of this review, it is demonstrated that DW holds a high diversity of Betaproteobacteria, whose presence may not be innocuous. Frequently belonging to genera also found in humans, DW Betaproteobacteria are ubiquitous in different habitats, have the potential to resist antibiotics either due to intrinsic or acquired mechanisms, and hold different virulence factors. The combination of these factors places DW Betaproteobacteria in the list of candidates of emerging opportunistic pathogens. Improved bacterial identification of clinical isolates associated with opportunistic infections and additional genomic and physiological studies may contribute to elucidate the potential impact of these bacteria.

Outbreak of Achromobacter xylosoxidans and Ochrobactrum anthropi Infections after Prostate Biopsies, France, 2014

We report an outbreak of healthcare-associated prostatitis involving rare environmental pathogens in immunocompetent patients undergoing transrectal prostate biopsies at Hôpital Édouard Herriot (Lyon, France) during August 13-October 10, 2014. Despite a fluoroquinolone-based prophylaxis, 5 patients were infected with Achromobacter xylosoxidans and 3 with Ochrobactrum anthropi, which has not been reported as pathogenic in nonimmunocompromised persons. All patients recovered fully. Analysis of the outbreak included case investigation, case-control study, biopsy procedure review, microbiologic testing of environmental and clinical samples, and retrospective review of hospital records for 4 years before the outbreak. The cases resulted from asepsis errors during preparation of materials for the biopsies. A low-level outbreak involving environmental bacteria was likely present for years, masked by antimicrobial drug prophylaxis and a low number of cases. Healthcare personnel should promptly report unusual pathogens in immunocompetent patients to infection control units, and guidelines should explicitly mention asepsis during materials preparation.

Characterization and genome comparisons of three Achromobacter phages of the family Siphoviridae

In this study, we present the characterization and genomic data of three Achromobacter phages belonging to the family Siphoviridae. Phages 83-24, JWX and JWF were isolated from sewage samples in Paris and Braunschweig, respectively, and infect Achromobacter xylosoxidans, an emerging nosocomial pathogen in cystic fibrosis patients. Analysis of morphology and growth parameters revealed that phages 83-24 and JWX have similar properties, both have nearly the same head and tail measurements, and both have a burst size between 85 and 100 pfu/cell. In regard to morphological properties, JWF had a much longer and more flexible tail compared to other phages. The linear double-stranded DNAs of all three phages are terminally redundant and not circularly permutated. The complete nucleotide sequences consist of 81,541 bp for JWF, 49,714 bp for JWX and 48,216 bp for 83-24. Analysis of the genome sequences showed again that phages JWX and 83-24 are quite similar. Comparison to the GenBank database via BLASTN revealed partial similarities to Roseobacter phage RDJL phi1 and Burkholderia phage BcepGomr. In contrast, BLASTN analysis of the genome sequence of phage JWF revealed only few similarities to non-annotated prophage regions in different strains of Burkholderia and Mesorhizobium.

Hospital Acquired Pneumonia Due to Achromobacter spp. in a Geriatric Ward in China: Clinical Characteristic, Genome Variability, Biofilm Production, Antibiotic Resistance and Integron in Isolated Strains

BACKGROUND

Hospital-acquired pneumonia (HAP) due to Achromobacter has become a substantial concern in recent years. However, HAP due to Achromobacter in the elderly is rare.

METHODS

A retrospective analysis was performed on 15 elderly patients with HAP due to Achromobacter spp., in which the sequence types (STs), integrons, biofilm production and antibiotic resistance of the Achromobacter spp. were examined.

RESULTS

The mean age of the 15 elderly patients was 88.8 ± 5.4 years. All patients had at least three underlying diseases and catheters. Clinical outcomes improved in 10 of the 15 patients after antibiotic and/or mechanical ventilation treatment, but three patients had chronic infections lasting more than 1 year. The mortality rate was 33.3% (5/15). All strains were resistant to aminoglycosides, aztreonam, nitrofurantoin, and third- and fourth-generation cephalosporins (except ceftazidime and cefoperazone). Six new STs were detected. The most frequent ST was ST306. ST5 was identified in two separate buildings of the hospital. ST313 showed higher MIC in cephalosporins, quinolones and carbapenems, which should be more closely considered in clinical practice. All strains produced biofilm and had integron I and blaOXA-114-like . The main type was blaOXA-114q . The variable region of integron I was different among strains, and the resistance gene of the aminoglycosides was most commonly inserted in integron I. Additionally, blaPSE-1 was first reported in this isolate.

CONCLUSION

Achromobacter spp. infection often occurs in severely ill elders with underlying diseases. The variable region of integrons differs, suggesting that Achromobacter spp. is a reservoir of various resistance genes.

A Case of Septic Shock caused by Achromobacter xylosoxidans in an Immunocompetent Female Patient after Extracorporeal Shock Wave Lithotripsy for a Ureteral Stone

Achromobacter xylosoxidans can cause various types of infections, but its infection in humans is rare. A. xylosoxidans has been reported as a rare etiological agent of infections including primary bacteremia, catheter-related bloodstream infection, endocarditis, otitis, and pneumonia, particularly in immunocompromised hosts. We encountered a case of septic shock caused by A. xylosoxidans in a 52-year-old, immunocompetent woman with no underlying disease, who received extracorporeal shock wave lithotripsy to remove a left upper ureteral stone. She was treated with antibiotics to which the organism was susceptible but died as a result of septic shock.

Achromobacter respiratory infections

Achromobacteria are ubiquitous environmental organisms that may also become opportunistic pathogens in certain conditions, such as cystic fibrosis, hematologic and solid organ malignancies, renal failure, and certain immune deficiencies. Some members of this genus, such as xylosoxidans, cause primarily nosocomially acquired infections affecting multiple organ systems, including the respiratory tract, urinary tract, and, less commonly, the cardiovascular and central nervous systems. Despite an increasing number of published case reports and literature reviews suggesting a global increase in achromobacterial disease, most clinicians remain uncertain of the organism's significance when clinically isolated. Moreover, effective treatment can be challenging due to the organism's inherent and acquired multidrug resistance patterns. We reviewed all published cases to date of non-cystic fibrosis achromobacterial lung infections to better understand the organism's pathogenic potential and drug susceptibilities. We found that the majority of these cases were community acquired, typically presenting as pneumonias (88%), and were most frequent in individuals with hematologic and solid organ malignancies. Our findings also suggest that achromobacterial lung infections are difficult to treat, but respond well to extended-spectrum penicillins and cephalosporins, such as ticarcillin, piperacillin, and cefoperazone.

Pseudomonas aeruginosa and Achromobacter sp. clonal selection leads to successive waves of contamination of water in dental care units

Dental care unit waterlines (DCUWs) consist of complex networks of thin tubes that facilitate the formation of microbial biofilms. Due to the predilection toward a wet environment, strong adhesion, biofilm formation, and resistance to biocides, Pseudomonas aeruginosa, a major human opportunistic pathogen, is adapted to DCUW colonization. Other nonfermentative Gram-negative bacilli, such as members of the genus Achromobacter, are emerging pathogens found in water networks. We reported the 6.5-year dynamics of bacterial contamination of waterlines in a dental health care center with 61 dental care units (DCUs) connected to the same water supply system. The conditions allowed the selection and the emergence of clones of Achromobacter sp. and P. aeruginosa characterized by multilocus sequence typing, multiplex repetitive elements-based PCR, and restriction fragment length polymorphism in pulsed-field gel electrophoresis, biofilm formation, and antimicrobial susceptibility. One clone of P. aeruginosa and 2 clones of Achromobacter sp. colonized successively all of the DCUWs: the last colonization by P. aeruginosa ST309 led to the closing of the dental care center. Successive dominance of species and clones was linked to biocide treatments. Achromobacter strains were weak biofilm producers compared to P. aeruginosa ST309, but the coculture of P. aeruginosa and Achromobacter enhanced P. aeruginosa ST309 biofilm formation. Intraclonal genomic microevolution was observed in the isolates of P. aeruginosa ST309 collected chronologically and in Achromobacter sp. clone A. The contamination control was achieved by a complete reorganization of the dental health care center by removing the connecting tubes between DCUs.

Fatal non-thrombotic pulmonary embolization in a patient with undiagnosed factitious disorder

Background

Factitious fever is extremely challenging to diagnose in patients with complicated chronic medical problems, and represents as much as 10% of fevers of unknown origin. Factitious fever caused by self-injecting oral medications through indwelling central catheters is a diagnostic challenge.

Case presentation

We present a 32-year-old Caucasian female with history of short gut syndrome, malnutrition requiring total parental nutrition, and pancreatic auto-islet transplant with fever of unknown origin. Multiple episodes of bacteremia occurred with atypical pathogens, including α-hemolytic Streptococcus, Achromobacter xylosoxidans, and Mycobacterium mucogenicum. Chest computed tomography was notable for extensive tree-in-bud infiltrates. Sudden cardiac arrest with right-sided heart failure following acute hypoxemia led to her death. Diffuse microcrystalline cellulose emboli with foreign body granulomatosis was found on autopsy. Circumstantial evidence indicated that this patient suffered from factitious disorder, and was self-injecting oral medications through her central catheter.

Conclusion

A high index of suspicion, early recognition, and multifaceted team support is essential to detect and manage patients with factitious disorders before fatal events occur.

Pitfalls in evidence assessment: the case of chlorhexidine and alcohol in skin antisepsis

Chlorhexidine has attracted increasing attention for its role in skin antisepsis in recent years. It was tested in several prominent clinical trials and subsequently recommended in important guidelines for blood culture collection, vascular catheter insertion and surgical skin preparation. We noticed and subsequently reported a widespread misinterpretation of evidence surrounding chlorhexidine and its role in skin antisepsis. Multiple clinical trial reports and systematic reviews that had assessed the clinical efficacy of chlorhexidine/alcohol combinations for skin antisepsis had attributed efficacy solely to the chlorhexidine component. This misinterpretation was carried over into the tertiary literature, including evidence-based guidelines. Here we discuss some of the scientific, ethical, patient safety and infection control implications of this misinterpretation, as well as broader implications for evidence-based medicine.

First genome sequences of Achromobacter phages reveal new members of the N4 family

BACKGROUND

Multi-resistant Achromobacter xylosoxidans has been recognized as an emerging pathogen causing nosocomially acquired infections during the last years. Phages as natural opponents could be an alternative to fight such infections. Bacteriophages against this opportunistic pathogen were isolated in a recent study. This study shows a molecular analysis of two podoviruses and reveals first insights into the genomic structure of Achromobacter phages so far.

METHODS

Growth curve experiments and adsorption kinetics were performed for both phages. Adsorption and propagation in cells were visualized by electron microscopy. Both phage genomes were sequenced with the PacBio RS II system based on single molecule, real-time (SMRT) technology and annotated with several bioinformatic tools. To further elucidate the evolutionary relationships between the phage genomes, a phylogenomic analysis was conducted using the genome Blast Distance Phylogeny approach (GBDP).

RESULTS

In this study, we present the first detailed analysis of genome sequences of two Achromobacter phages so far. Phages JWAlpha and JWDelta were isolated from two different waste water treatment plants in Germany. Both phages belong to the Podoviridae and contain linear, double-stranded DNA with a length of 72329 bp and 73659 bp, respectively. 92 and 89 putative open reading frames were identified for JWAlpha and JWDelta, respectively, by bioinformatic analysis with several tools. The genomes have nearly the same organization and could be divided into different clusters for transcription, replication, host interaction, head and tail structure and lysis. Detailed annotation via protein comparisons with BLASTP revealed strong similarities to N4-like phages.

CONCLUSIONS

Analysis of the genomes of Achromobacter phages JWAlpha and JWDelta and comparisons of different gene clusters with other phages revealed that they might be strongly related to other N4-like phages, especially of the Escherichia group. Although all these phages show a highly conserved genomic structure and partially strong similarities at the amino acid level, some differences could be identified. Those differences, e.g. the existence of specific genes for replication or host interaction in some N4-like phages, seem to be interesting targets for further examination of function and specific mechanisms, which might enlighten the mechanism of phage establishment in the host cell after infection.

Isolation and characterization of numerous novel phages targeting diverse strains of the ubiquitous and opportunistic pathogen Achromobacter xylosoxidans

The clinical relevance of nosocomially acquired infections caused by multi-resistant Achromobacter strains is rapidly increasing. Here, a diverse set of 61 Achromobacter xylosoxidans strains was characterized by MultiLocus Sequence Typing and Phenotype MicroArray technology. The strains were further analyzed in regard to their susceptibility to 35 antibiotics and to 34 different and newly isolated bacteriophages from the environment. A large proportion of strains were resistant against numerous antibiotics such as cephalosporines, aminoglycosides and quinolones, whereas piperacillin-tazobactam, ticarcillin, mezlocillin and imipenem were still inhibitory. We also present the first expanded study on bacteriophages of the genus Achromobacter that has been so far a blank slate with respect to phage research. The phages were isolated mainly from several waste water treatment plants in Germany. Morphological analysis of all of these phages by electron microscopy revealed a broad diversity with different members of the order Caudovirales, including the families Siphoviridae, Myoviridae, and Podoviridae. A broad spectrum of different host ranges could be determined for several phages that lysed up to 24 different and in part highly antibiotic resistant strains. Molecular characterisation by DNA restriction analysis revealed that all phages contain linear double-stranded DNA. Their restriction patterns display distinct differences underlining their broad diversity.

Skin and soft tissue infection caused by Achromobacter xylosoxidans: report of 14 cases

BACKGROUND

Skin and soft tissue infections (SSTIs) caused by Achromobacter xylosoxidans are very infrequent. The aim of the present study was to investigate the clinical and microbiological characteristics of this infection.

METHODS

We carried out a retrospective review of 14 cases of SSTI due to A. xylosoxidans that occurred at the University Hospital of Guadalajara (Spain) from January 2007 to December 2012.

RESULTS

The infection was secondary to vascular diseases, trauma, and recent surgery in 12 patients (85.7%). The most frequent clinical presentation was infection of a vascular ulcer (5 cases). The infection was monomicrobial in 7 patients (50%) and 9 cases were community-acquired (64.2%). The clinical outcome of the patients was uniformly good after antibiotic treatment, except in 4 patients who suffered recurrence of the infection.

CONCLUSION

A. xylosoxidans should be considered a potential pathogen in patients with SSTIs, especially in patients with vascular diseases or after surgery or trauma. A history of contact with water should be investigated in all cases. Treatment can be difficult due to the high level of antibiotic resistance. Trimethoprim-sulfamethoxazole may be useful for treatment in outpatients with community-acquired infections.

Bacteremia due to Achromobacter xylosoxidans in neonates: clinical features and outcome

Objective

We report an outbreak of Achromobacter xylosoxidans at a neonatal intensive care unit. We aimed to present clinical, laboratory and treatment data of the patients.

Materials and methods

All consecutive episodes of bacteremia due to A. xylosoxidans at our neonatal intensive care unit, beginning with the index case detected at November 2009 until cessation of the outbreak in April 2010, were evaluated retrospectively.

Results

Thirty-four episodes of bacteremia occurred in 22 neonates during a 6-month period. Among the affected, 90% were preterm newborns with gestational age of 32 weeks or less and 60% had birth weight of 1000 g or less. Endotracheal intubation, intravenous catheter use, total parenteral nutrition and prolonged antibiotic therapy were the predisposing conditions. Presenting features were abdominal distention, thrombocytopenia and neutropenia. The mortality rate was 13.6% and the majority of isolates were susceptible to piperacillin-tazobactam, carbapenems and trimethoprim-sulfametoxazole, and resistant to gentamycin. More than half were breakthrough infections. Despite intensive efforts to control the outbreak by standard methods of hand hygiene, patient screening and isolation, containment could be achieved only after the neonatal intensive care unit was relocated. The investigation was not able to single out the source of the outbreak.

Conclusion

A. xylosoxidans has the potential to cause serious infections in premature babies. More studies are needed to determine the importance of different sources of infection in hospital units.

Investigation and control of an outbreak of Achromobacter xylosoxidans bacteremia

OBJECTIVE

To define the extent of an outbreak of Achromobacter xylosoxidans bacteremia, determine the source of the outbreak, and implement control measures.

DESIGN

An outbreak investigation, including environmental and infection control assessment, and evaluation of hypotheses using the binomial distribution and case control studies.

SETTING

A 50-bed medical surgical unit in a hospital in Illinois during the period January 1-July 15, 2006.

INTERVENTIONS

Discontinuation of use of opioid delivery via patient-controlled analgesia (PCA) until the source of the outbreak was identified and implementation of new protocols to ensure more rigorous observation of PCA pump cartridge manipulations.

RESULTS

Calculations based on the binomial distribution indicated the probability that all 9 patients with A. xylosoxidans bacteremia were PCA pump users by chance alone was <.001. A subsequent case control study identified PCA pump use for administration of morphine as a risk factor for A. xylosoxidans bacteremia (odds ratio, undefined; P < .001). Having a PCA pump cartridge with morphine started by nurse C was significantly associated with becoming a case-patient (odds ratio, 46; 95% confidence interval, 4.0-525.0; P < .001).

CONCLUSIONS

We hypothesize that actions related to diversion of morphine by nurse C were the likely cause of the outbreak. An aggressive pain control program involving the use of opioid medication warrants an equally aggressive policy to prevent diversion of medication by staff.

Achromobacter species endocarditis: A case report and literature review

Endocarditis due to Achromobacter species is a rare, yet serious, endovascular infection. Achromobacter species infective endocarditis is associated with underlying immunodeficiencies or prosthetic heart valves and devices. A case of prosthetic pulmonary valve endocarditis secondary to Achromobacter xylosoxidans subspecies denitrificans is described in the present report. This life-threatening infection was successfully treated with combined valve replacement and prolonged antibiotic therapy. A Medline/PubMed literature review of Achromobacter endocarditis was also performed. Achromobacter species are an uncommon, yet important, cause of nosocomial endocarditis. Given the significant associated morbidity and mortality, along with a high degree of intrinsic antibiotic resistance, Achromobacter species infective endocarditis remains a clinical treatment challenge.

Multilocus sequence analysis of isolates of Achromobacter from patients with cystic fibrosis reveals infecting species other than Achromobacter xylosoxidans

A multilocus sequence analysis (MLSA) scheme was developed for characterization of strains and species from the genus Achromobacter, which are increasingly recovered from patients with cystic fibrosis (CF). Five conserved housekeeping genes were selected for the MLSA, which was applied to a diverse collection of 77 strains originating from Europe, Asia, and South America and including type strains of the seven recognized Achromobacter species, six environmental strains, eight non-CF clinical strains, and 56 CF clinical strains. The discriminatory power of MLSA, based on 2,098 nucleotides (nt), was much superior to a 16S rRNA gene comparison based on 1,309 nt. Congruence was observed between single-gene trees and a concatenated gene tree. MLSA differentiated all seven current Achromobacter species and also demonstrated the presence of at least four novel potential species within the genus. CF isolates were predominantly Achromobacter xylosoxidans (64%), an undescribed Achromobacter species (18%), and Achromobacter ruhlandii (7%). A clone of Achromobacter, which has spread among patients from Danish CF centers in Aarhus and Copenhagen, was identified as Achromobacter ruhlandii. MLSA facilitates the specific identification of isolates of Achromobacter necessary for describing their role in clinical infections.

Achromobacter xylosoxidans respiratory tract infection in cystic fibrosis patients

The aims of this study were to evaluate the frequency of Achromobacter xylosoxidans infection in a cohort of cystic fibrosis patients, to investigate antimicrobial sensitivity, to establish possible clonal likeness among strains, and to address the clinical impact of this infection or colonization on the general outcome of these patients. The study was undertaken between January 2004 and December 2008 on 300 patients receiving care at the Regional Cystic Fibrosis Center of the Naples University "Federico II". Sputum samples were checked for bacterial identification. For DNA fingerprinting, pulsed-field gel electrophoresis (PFGE) was carried out. Fifty-three patients (17.6%) had at least one positive culture for A. xylosoxidans; of these, 6/53 (11.3%) patients were defined as chronically infected and all were co-colonized by Pseudomonas aeruginosa. Of the patients, 18.8% persistently carried multidrug-resistant isolates. Macrorestriction analysis showed the presence of seven major clusters. DNA fingerprinting also showed a genetic relationship among strains isolated from the same patients at different times. The results of DNA fingerprinting indicate evidence of bacterial clonal likeness among the enrolled infected patients. We found no significant differences in the forced expiratory volume in 1 s (FEV(1)) and body mass index (BMI) when comparing the case group of A. xylosoxidans chronically infected patients with the control group of P. aeruginosa chronically infected patients.

Catheter-related bloodstream infections: catheter management according to pathogen

Central-line access is an essential part of modern healthcare practice; however, catheter-related bloodstream infection is a major problem that causes substantial morbidity and mortality, and excess length of stay and cost. The risk of infection depends on the type of device, the site of insertion, the underlying conditions and the appropriate prevention measures taken during catheter insertion. Management of catheter-related bloodstream infection involves deciding on catheter removal, antimicrobial catheter lock solution and the type and duration of systemic antimicrobial therapy. Systemic antimicrobial use is essential but, although generally effective in controlling sepsis, it often fails to sterilise the line, increasing the incidence of complications or recurrence. The decision regarding whether the catheter should be removed or retained is therefore crucial. One of the major factors to be considered is the type of organism involved in the catheter-related infection. This review outlines the epidemiology, pathogenesis, diagnosis, microbiology and management of catheter-related infections, mainly focusing on the management of the intravascular device according to the pathogen.

Achromobacter xylosoxidans genomic characterization and correlation of randomly amplified polymorphic DNA profiles with relevant clinical features [corrected] of cystic fibrosis patients

Achromobacter xylosoxidans is an emerging pathogen increasingly being isolated from respiratory samples of cystic fibrosis (CF) patients. Its role and clinical significance in lung pathogenesis have not yet been clarified. The aim of the present study was to genetically characterize A. xylosoxidans strains isolated from CF patients by use of randomly amplified polymorphic DNA (RAPD) profiles and to look for a possible correlation between RAPD profiles and the patients' clinical features, such as their spirometry values, the presence of concomitant chronic bacterial flora at the time of isolation, and the persistent or intermittent presence of A. xylosoxidans strains. A set of 106 strains of A. xylosoxidans were typed by RAPD analysis, and their profiles were analyzed by agglomerative hierarchical classification (AHC) and associated with the patient characteristics mentioned above by factorial discriminant analysis (FDA). The overall results obtained in this study showed that (i) there is a marked genetic relationship between strains isolated from the same patients at different times, (ii) characteristic RAPD profiles are associated with different predicted classes for forced expiratory volume in 1 s (FEV1%), (iii) some characteristic RAPD profiles are associated with different concomitant chronic flora (CCF) profiles, and (iv) there is a significant division of RAPD profiles into "persistent strains" and "intermittent strains" of A. xylosoxidans. These findings seem to imply that the lung habitats found in CF patients are capable of shaping and selecting the colonizing bacterial flora, as seems to be the case for the A. xylosoxidans strains studied.

Urinary tract infection due toAchromobacter xylosoxidans: Report of 9 cases

Urinary tract infection (UTI) due to Achromobacter xylosoxidans is rare. The aims were to know the frequency and clinical characteristics of this infection in our area. We performed a retrospective analysis of 9 patients with UTI caused by this organism diagnosed over a period of 13 y. The mean age was 63.1 y. All patients had underlying diseases or urological abnormalities. The most frequent underlying diseases were solid or hematological malignancies (3 cases). Seven patients (77.7%) had urological abnormalities. Eight patients had symptoms of cystitis and 1 remained asymptomatic. Seven patients had community acquired UTIs. Clinical outcome was favourable in 5 patients after antibiotic treatment and recurrence occurred in 3 patients who had urological abnormalities. All isolates were susceptible to imipenem and piperacillin-tazobactam, 88.8% were susceptible to ceftazidime and 77.7% were susceptible to trimethoprim-sulfamethoxazole. High frequencies of resistance to ampicillin (100%), amoxicillin/clavulanic acid (78%), cefuroxime (100%), cefotaxime (67%), norfloxacin (89%), ciprofloxacin (78%), nitrofurantoin (89%) and gentamicin (67%) were observed. UTI due to A. xylosoxidans was predominantly observed in elderly patients with predisposing factors, especially urological abnormalities, malignancies and immunosuppression. Treatment can be difficult due to the high level of antibiotic resistance. Trimethoprim-sulfamethoxazole may be useful for treatment, particularly in outpatients with community acquired infections.

Alcaligenes xylosoxidansBloodstream Infections in Outpatient Oncology Office

Gaps in infection control led to biofilm production in central venous catheters and resultant bloodstream infection.

In 2002, we investigated a cluster of patients with Alcaligenes xylosoxidans bloodstream infections by conducting a matched case–control study and a prospective study. Pulsed-field gel electrophoresis (PFGE) was performed on blood culture isolates, and 1 explanted central venous catheter (CVC) was tested for biofilm. We identified 12 cases of A. xylosoxidans bloodstream infection. Case-patients were more likely than controls to have had a CVC (7/7 [100%] vs 4/47 [8.7%], respectively; p<0.0001). Ten case isolates were indistinguishable by PFGE analysis, and A. xylosoxidans biofilm from the CVC matched the outbreak strain. We observed multiple breaches in infection control, which may have caused contamination of multidose vials used to flush the CVCs. Our study links A. xylosoxidans with CVC biofilm and highlights areas for regulation and oversight in outpatient settings.

Avoiding trouble down the line: the management and prevention of hemodialysis catheter-related infections

Over the last 2 decades, hemodialysis catheter use has increased. Annually, approximately 30% of patients using a central venous catheter (CVC) experience a septic or bacteremic episode and are subsequently at risk of its associated long-term complications and mortality. Because of the serious clinical and financial impact of hemodialysis catheter-related bacteremias (HCRIs), standardized, validated definitions based on the hemodialysis patient population are necessary in order to better diagnose, monitor, and report HCRI for patient quality assurance and research purposes. The pathophysiology of HCRI involves a complex interaction between a triad that consists of the host patient, the infecting microorganism, and the vehicle catheter. Although the microorganism contribution in the pathogenesis of HCRI is likely most important, certain patient and catheter-related characteristics may be more amenable to manipulation. The key to managing HCRI is on prophylaxis against the initial microorganism catheter adherence and subsequent biofilm development. General and specific prophylactic maneuvers directed at both an intravascular and extraluminal route of microorganism entry are discussed including antibiotic- and silver-impregnated catheters and dressings, subcutaneous access devices, and topical prophylaxis at the exit site. In addition to systemic antibiotic use, the 3 methods of HRCI treatment using catheter salvage, guidewire exchange, and concurrent antibiotic lock are compared. The outcome and complications of HCRI may be serious and highlight the importance of careful, continual infection surveillance. Although the use of a multidisciplinary hemodialysis infection control team is desirable, staffing education and physician feedback have been shown to improve adherence to infection control guidelines and reduce HCRI.