Central venous catheter-associated Leifsonia aquatica bacteremia in a hemodialysis-dependent patient

Leifsonia aquatica: Case report and literature review

Non-diphtheria Corynebacterium species have been increasingly recognized as multidrug resistant pathogens that also infect immunocompromised patients. Automated and semi-automated phenotypic tests have been used by clinical laboratories for detection of these gram-positive rods. The present case report describes the rare pediatric case of L. aquatica isolated in central venous catheter blood cultures during chemotherapy treatment for Wilms tumor and adds to the knowledge on this infection with regard to pediatric cancer. The clinical aspects of this patient and opportunities for improving treatment were reviewed. Additionally, a review of the literature revealed no other case report involving cancer and a pediatric patient with documented L. aquatica bacteremia. Corynebacterial infections are considered uncommon, but in recent decades' reports on infection with bacterium are increasing in frequency, particularly in nosocomial immunocompromised patients.

Leifsonia Species Bacteremia in a Hemodialysis Patient: A Difficult-to-Identify Organism

Leifsonia is an environmental gram-positive rods bacteria. Infections due to Leifsonia are not common. In this report, we present a case of a hemodialysis patient with Leifsonia bacteremia.

A 56-year-old lady had been receiving hemodialysis through the femoral line. She presented with nonspecific symptoms. Multiple blood cultures taken from the central line and peripherally grew gram-positive bacilli, which were identified by polymerase chain reaction (PCR) as Leifsonia species. This serious infection resolved only after the removal of the central venous catheter (CVC) and treatment with vancomycin for four weeks from the first negative blood culture.

Leifsonia species are a rare cause of CVC-associated infections. Leifsonia should be considered in hemodialysis patients with gram-positive rod bacteremia. Leifsonia also has the ability to produce a biofilm. Removal of the line along with antibiotics is necessary to cure the infection.

Antibiotic Resistance of Airborne Viable Bacteria and Size Distribution in Neonatal Intensive Care Units

Despite their significant impact on public health, antibiotic resistance and size distributions of airborne viable bacteria in indoor environments in neonatal intensive care units (NICU) remain understudied. Therefore, the objective of this study was to assess the antibiotic resistance of airborne viable bacteria for different sizes (0.65–7 µm) in private-style and public-style neonatal intensive care units (NICU). Airborne bacteria concentrations were assessed by a six-stage Andersen impactor, operating at 28.3 L/min. Public-style NICU revealed higher concentrations of airborne viable bacteria (53.00 to 214.37 CFU/m³) than private-style NICU (151.94–466.43), indicating a possible threat to health. In the public-style NICU, Staphylococcus was the highest bacterial genera identified in the present study, were Staphylococcus saprophyticus and Staphylococcus epidermidis predominated, especially in the second bronchi and alveoli size ranges. Alloiococcus otitidis, Bacillus subtiles, Bacillus thuringiensis, Kocuria rosea, and Pseudomonas pseudoalcaligene, were identified in the alveoli size range. In NICU#2, eight species were identified in the alveoli size range: Bacillus cereus, Bacillus subtilis, Bacillus thuringiensis, Eikenella corrodens, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus gordoni. Multi-drug-resistant organisms (MDROs) were found in both of the NICUs. Bacillus cereus strains were resistant to Ampicillin, Cefoxitin, Ceftaroline, and Penicillin G. Staphylococcus cohnii ssp. cohnii was resistant in parallel to ampicillin and G penicillin. Staphylococcus saprophyticus strains were resistant to Ampicillin, Penicillin G, Oxaxilin, and Erythromycin. Results may indicate a potential threat to human health due to the airborne bacteria concentration and their antibiotic resistance ability. The results may provide evidence for the need of interventions to reduce indoor airborne particle concentrations and their transfer to premature infants with underdeveloped immune systems, even though protocols for visitors and cleaning are well-established.

Molecular identification of clinical "difficult-to-identify" microbes from sequencing 16S ribosomal DNA and internal transcribed spacer 2

Background

Clinical microbiology laboratories have to accurately identify clinical microbes. However, some isolates are difficult to identify by the automated biochemical text platforms, which are called “difficult-to-identify” microbes in this study. Therefore, the ability of 16S ribosomal DNA (16S rDNA) and internal transcribed spacer 2 (ITS2) sequencing to identify these “difficult-to-identify” bacteria and fungi was assessed in this study.

Methods

Samples obtained from a teaching hospital over the past three years were examined. The 16S rDNA of four standard strains, 18 clinical common isolates, and 47 “difficult-to-identify” clinical bacteria were amplified by PCR and sequenced. The ITS2 of eight standard strains and 31 “difficult-to-identify” clinical fungi were also amplified by PCR and sequenced. The sequences of 16S rDNA and ITS2 were compared to reference data available in GenBank by using the BLASTN program. These microbes were identified according to the percentage of similarity to reference sequences of strains in GenBank.

Results

The results from molecular sequencing methods correlated well with automated microbiological identification systems for common clinical isolates. Sequencing results of the standard strains were consistent with their known phenotype. Overall, 47 “difficult-to-identify” clinical bacteria were identified as 35 genera or species by sequence analysis (with 10 of these identified isolates first reported in clinical specimens in China and two first identified in the international literature). 31 “difficult-to-identify” clinical fungi tested could be identified as 15 genera or species by sequence analysis (with two of these first reported in China).

Conclusions

Our results show the importance of 16S rDNA and internal ITS2 sequencing for the molecular identification of “difficult-to-identify” bacteria and fungi. The development of this method with advantages of convenience, availability, and cost-effectiveness will make it worth extending into clinical practice in developing countries.

Septicemia caused by Leifsonia aquatica in a healthy patient after retinal reattachment surgery

Leifsonia aquatica is an aquatic bacterium that is typically found in environmental water habitats. Infections due to L. aquatica are rare and commonly catheter associated in immunocompromised patients. We report the first case of an acute septicemia caused by L. aquatica in a healthy immunocompetent host after cryopexy in the absence of a catheter.

Peritonitis caused by Haemophilus parainfluenzae, Leifsonia aquatica, and Gordonia spp. in a patient undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Peritonitis has remained the most common serious complication of continuous ambulatory peritoneal dialysis (CAPD). In most cases, these infections are monomicrobial, and the pathogens involved most commonly are Staphylococci. Recently, polymicrobial infections with rare organisms have been reported more often.

CASE REPORT

We describe a patient who developed recurrent episodes of CAPD-associated peritonitis with a total of four pathogens: Methicillin-resistant S. aureus, Haemophilus parainfluenzae, Leifsonia aquatica, and Gordonia spp. The infection most likely was acquired when the patient used tap water for dialysis during a camping trip. All episodes were treated successfully with antibiotics. Finally, the device was removed, and later, a new catheter was implanted, which still is in use.

CONCLUSION

Peritoneal dialysis-associated peritonitis may be caused by rare organisms. Antibiotics may be able to treat disease temporarily, but removal of contaminated catheters usually is required.

The genus corynebacterium and other medically relevant coryneform-like bacteria

Catalase-positive Gram-positive bacilli, commonly called "diphtheroids" or "coryneform" bacteria were historically nearly always dismissed as contaminants when recovered from patients, but increasingly have been implicated as the cause of significant infections. These taxa have been underreported, and the taxa were taxonomically confusing. The mechanisms of pathogenesis, especially for newly described taxa, were rarely studied. Antibiotic susceptibility data were relatively scant. In this minireview, clinical relevance, phenotypic and genetic identification methods, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) evaluations, and antimicrobial susceptibility testing involving species in the genus Corynebacterium and other medically relevant Gram-positive rods, collectively called coryneforms, are described.