Successful treatment of multiresistant Achromobacter xylosoxidans bacteremia in a child with acute myeloid leukemia

Meropenem-Resistant Achromobacter xylosoxidans, Subspecies Denitrificans Bacteremia in a Patient With Stage IV Adenocarcinoma of the Lung

Achromobacter xylosoxidans,subspecies denitrificans is a rare Gram-negative bacillus that causes health care associated infections in immunocompromised hosts. Carbapenems and anti-pseudomonal penicillins are listed as suitable empiric therapy in the literature. Herein, we report a case of a 77-year-old male with stage IV adenocarcinoma of the lung who presented with and was improving from Salmonella javiana enterocolitis, only to subsequently develop A. xylosoxidans,subspecies denitrificans bacteremia that was resistant to both meropenem and piperacillin-tazobactam. With empiric antibiotic coverage falling short of microbial clearance, timelyin vitrosusceptibility testing and prompt infectious disease consultation are of the utmost importance for treatment.

Nosocomial Achromobacter xylosoxidans Infection Presenting as a Cavitary Lung Lesion in a Lung Cancer Patient

Achromobacter xylosoxidans is a Gram-negative bacillus that is known to cause nosocomial infections, primarily in patients with hematological malignancies. The most common primary manifestation is bacteremia. We report a novel case of primary A. xylosoxidans infection presenting as a cavitary lung lesion with associated pneumonia in a lung cancer patient who showed no evidence of malignant disease progression after radiation therapy. Our patient was initially admitted for acute hypoxic respiratory failure requiring mechanical ventilation. Initial computed tomography (CT) revealed a cavitary lesion in the right upper lobe of the lung. Diagnostic bronchoscopy with bronchoalveolar lavage (BAL) was performed and was negative for infectious etiologies including tuberculosis (TB) and fungal infections. Cytology was also negative for malignancy. However, the bacterial culture grew A. xylosoxidans. Antimicrobial therapy was initiated based on culture susceptibilities and the patient showed significant improvement in oxygen requirements. Due to poor functional status, the palliative care route was pursued and mechanical ventilation weaning was not performed. Cavitary pulmonary infections secondary to A. xylosoxidans are rarely reported in the medical literature. After conducting a thorough PubMed database search of the medical literature, we believe this is the first case of A. xylosoxidans infection manifesting as a cavitary lung lesion with associated pneumonia in a lung cancer patient.

Preliminary experience with tigecycline treatment for severe infection in children

Severe infection is a primary cause of mortality in children facing challenges from multidrug-resistant (MDR) pathogens, particularly MDR Acinetobacter baumannii. Tigecycline has an expanded spectrum of antibacterial activity, and some successful instances of its use in children have been reported. We conducted a retrospective chart review of children treated at a tertiary hospital between May 1, 2012 and May 1, 2017 to examine the efficacy and safety of tigecycline in children with severe infection. A total of 110 patients (69 males) were enrolled in this study, including 46 MDR A. baumannii infection patients, encompassing 51 A. baumannii strains. Totally, the median duration of tigecycline therapy was 10 days (range, 2-47 days), with a clinical improvement rate of 47.27% (52/110). In A. baumannii infection group, the clinical improvement rate was 50% (23/46) and the microbiology eradication rate was 50.98% (26/51). No adverse events were reported during therapy; however, in one case, a 9-year-old boy with hematologic disease developed tooth discoloration.Conclusion: Although some patients benefited from tigecycline, the efficacy and safety of tigecycline should not be overvalued. Additional data from randomized controlled trials are required to assess the administration of tigecycline. What is Known: • Severe infection is a primary cause of mortality in pediatric patients and its treatment is facing challenges from an increasing number of multidrug-resistant (MDR) pathogens. • Tigecycline has an expanded spectrum of antibacterial activity. • Several case reports have indicated that tigecycline could be used as a salvage therapy in children when options are limited or non-existent. What is New: • We found that rate of clinical improvement was different in various groups of different infection. The efficacy of tigecycline should not be overvalued. • Six dosage models and different infection types were observed in our series, with different improvement and eradication rate, indicating that more data are required to identify a proper tigecycline dosage.

Preliminary experience of tigecycline treatment for infection in children with hematologic malignancies

Background Severe infection is life-threatening in children with hematologic malignancies and its treatment is challenging because of an increasing number of multidrug-resistant pathogens. Tigecycline has an expanded antibacterial activity spectrum; some successful cases of tigecycline treatment have been reported in the literature. Objective To examine the efficacy and safety of tigecycline in children. Setting Department of hematologic malignancies in a tertiary hospital. Method A retrospective chart review from May 1, 2012 to May 1, 2017. The patients were identified by the hospital information system and a custom-made Microsoft Excel 2007 database of patients was created to record demographic and medical data. Main outcome measure Efficacy and safety of tigecycline use in severe infection children with hematologic malignancies. Results Thirty-seven patients were enrolled and the predominant diagnosis was acute lymphoblastic leukemia. The median duration of tigecycline therapy was 9 days. Most prescriptions were empirical. Eighteen patients received a maintenance dose of 2 mg/kg q12 h, without a loading dose. Sulperazone was the most frequently prescribed concomitant drug. At the end of tigecycline therapy, improvement was observed in 48.7% of cases. After treatment, interleukin-10 levels notably decreased. The only reported adverse event was a case of tooth discoloration. Conclusion Tigecycline can be used as salvage therapy in children with hematologic malignancy and seems tolerable. Prospective controlled studies are required to definitively evaluate the efficacy and safety of tigecycline in children.

Use of tigecycline in pediatric clinical practice

INTRODUCTION

Tigecycline, a derivative of minocycline, is an extended-spectrum antimicrobial agent. It has a restricted approval field in children and the experience of its adoption in clinical practice is reserved for cases of challenging infections. The aim of this review was to summarize evidence regarding the use of tigecycline in infants and children, focusing on the drug's clinical efficacy data and tolerability profile. Areas covered: We have conducted a literature search of the Cochrane Library, EMBASE, and MEDLINE databases, from their inception through 5 January 2017, using the following terms: tigecycline, newborn, infant, child, pediatrics, adolescent, human, clinical trial, and case report. Articles were excluded if they were redundant or not pertinent. Bibliographies of all relevant articles were also evaluated. Seventeen publications were included: 1 pharmacokinetic study, 16 case reports. In the selected publications, the patients' mean age was 4.45 years, 38.7% of children was <3 years old and favorable clinical response was achieved in 74.2% of cases. Expert commentary: Tigecycline may be a considerable option in life-threatening infections in pediatric patients. Its administration is well tolerated and has demonstrated a good clinical response in nonbacteremic patients. However, the available clinical records are limited and more studies are needed.

The Antibiotic Drug Tigecycline: A Focus on its Promising Anticancer Properties

Tigecycline (TIG), the first member of glycylcycline bacteriostatic agents, has been approved to treat complicated infections in the clinic because of its expanded-spectrum antibiotic potential. Recently, an increasing number of studies have emphasized the anti-tumor effects of TIG. The inhibitory effects of TIG on cancer depend on several activating signaling pathways and abnormal mitochondrial function in cancer cells. The aim of this review is to summarize the cumulative anti-tumor evidence supporting TIG activity against different cancer types, including acute myeloid leukemia (AML), glioma, non-small cell lung cancer (NSCLC), among others. In addition, the efficacy and side effects of TIG in cancer patients are summarized in detail. Future clinical trials are also to be discussed that will evaluate the security and validate the underlying the tumor-killing properties of TIG.

Characterization of a novel Achromobacter xylosoxidans specific siphoviruse: phiAxp-1

Bacteriophages have recently been considered as an alternative biocontrol tool because of the widespread occurrence of antimicrobial-resistant Achromobacter xylosoxidans. Herein, we isolated a virulent bacteriophage (phiAxp-1) from a water sample of the Bohai sea of China that specifically infects A. xylosoxidans. Transmission electron microscopy revealed that phage phiAxp-1 belongs to the Siphoviridae. We sequenced the genome of phiAxp-1, which comprises 45,045 bp with 64 open reading frames. Most of the proteins encoded by phiAxp-1 have no similarity to sequences in the public databases. Twenty-one proteins with assigned functions share weak homology with those of other dsDNA bacteriophages infecting diverse hosts, such as Burkholderia phage KL1, Pseudomonas phage 73, Pseudomonas phage vB_Pae-Kakheti25, Pseudomonas phage vB_PaeS_SCH_Ab26, Acinetobacter phage IME_AB3 and Achromobacter phage JWX. The genome can be divided into different clusters for the head and tail structure, DNA replication and mazG. The sequence and genomic organization of bacteriophage phiAxp-1 are clearly distinct from other known Siphoviridae phages; therefore, we propose that it is a member of a novel genus of the Siphoviridae family. Furthermore, one-step growth curve and stability studies of the phage were performed, and the specific receptor of phiAxp-1 was identified as the lipopolysaccharide of A. xylosoxidans.