The Bacteremia Caused by Non-Lactose Fermenting Gram-Negative Bacilli in Solid Organ Transplant Recipients

Risk Factors and Outcome of Gram-Negative Bloodstream Infection in Living-Donor Renal Transplant Recipients: A Case-Control Study From Pakistan

OBJECTIVES

Gram-negative rods are the most common cause of bloodstream infection in renal transplant recipients. Acute rejection, urologic abnormalities, and ureteral stents are risk factors. Graft dysfunction is independently associated with gram-negative rod bloodstream infection. Our aim is to investigate the incidence, risk factors, and outcome among living donor renal transplant recipients from Pakistan.

MATERIALS AND METHODS

In this case-control study, we reviewed the medical records until June 2021 of renal transplant recipients seen from 2015 to 2019 for gram negative bacteremia. For every case, controls were matched by age, date of transplant, and sex. Demographics, risk factors, graft function, and mortality were compared. Clinical features, immunosuppression, source of blood stream infection, and microbiology were noted in cases.

RESULTS

Of 1677 renal transplant recipients, 44 developed gram negative bacteremia. The incidence was 5.9 per 1000 person-years. Median time since transplant was 5 months. The most common source was urinary tract infection. On univariate analysis, antithymocyte globulin, urinary tract infection, and recurrent urinary tract infections were associated with gram negative bacteremia. On multivariate analysis, urinary tract infection (adjusted odds ratio = 3.46; 95% CI, 1.27-9.37) and recurrent urinary tract infections (adjusted odds ratio = 4.03; 95% CI, 1.15-14.15) were significant risk factors. We found no difference in 30-day mortality and estimated glomerular filtration rate on last follow-up between cases and controls. Kaplan-Meier survival curves showed significant differences in graft survival in patients with gram negative bacteremia. Escherichia coli was the most common organism, with 75% ceftriaxone and 13% imipenem resistance.

CONCLUSIONS

The most significant risk factor for gram negative rod bloodstream infection was recurrent urinary tract infections. Timely treatment and prevention of recurrent urinary tract infections areimperative for prevention of gram negative bacteremia.

Microbiological Characterization and Clinical Facets of Elizabethkingia Bloodstream Infections in a Tertiary Care Hospital of Eastern India

Purpose

Elizabethkingia is an emerging non-fermenting Gram-negative bacillus (NFGNB) causing bloodstream infections (BSI) associated with high mortality. It demonstrates a unique antimicrobial profile in showing susceptibility to antimicrobials effective against Gram-positive bacteria. This study was undertaken to determine the overall frequency of Elizabethkingia BSI, associated risk factors, microbiological susceptibility, and clonal relationship of Elizabethkingia isolates using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR).

Patients and Methods

Elizabethkingia isolates obtained from the blood culture of admitted patients (August 2020-December 2021) were identified by the VITEK 2 system and subjected to an antimicrobial susceptibility test by standard procedures. Demographics, co-morbidities, risk factors for survival, and outcome were summarized and analyzed by Chi-square test, Kaplan-Meier curve, and Cox regression. Clonal relatedness between Elizabethkingia isolates was analyzed using ERIC‑PCR fingerprinting with the "PAST: Paleontological statistics software package".

Results

Of 13,747 blood samples received during the study period, 13.59% were culture positive, and 14.60% were NFGNBs. The frequency of Elizabethkingia spp. among all NFGNBs in BSI was 29.30%, and the overall prevalence in BSI was 4.21%. In patients with Elizabethkingia BSI, Foley's catheter was present in 81.25% of the cases. 100% susceptibility was observed to linezolid, followed by vancomycin (98.75%) and chloramphenicol (89.5%). The 30-day mortality rate in the patients of Elizabethkingia BSI was 26.25%. The Presence of COVID-19, pneumonia, diabetes mellitus (DM), mechanical ventilation (MV), and prior antibiotics were significantly different (p<0.05) between the survival and death groups. ERIC-PCR profile dendrogram of Elizabethkingia isolates showed ten major clusters indicating high genetic diversity.

Conclusion

Elizabethkingia was responsible for one-third of NFGNB BSI in a single-center study, with approximately 26% of 30-day all-cause mortality. Most isolates were susceptible to linezolid, vancomycin, and chloramphenicol. COVID-19 was the most significant risk factor associated with mortality. ERIC-PCR of Elizabethkingia isolates exhibited high genetic diversity.

Follow-Up Blood Culture Practices for Gram-Negative Bloodstream Infections in Immunocompromised Hosts at a Large Academic Medical Center

The role of follow-up blood cultures (FUBC) in gram-negative (GN) bloodstream infections (BSI) to improve clinical outcomes remains controversial, especially among immunocompromised patients. Among 139 patients, FUBCs were common (117, 84.2%); however, positive FUBCs were rare (3, 2.6%). Only presence of fever was associated with positive FUBC.