Serum vancomycin levels predict the short-term adverse outcomes of peritoneal dialysis–associated peritonitis

Background: The role of monitoring serum vancomycin levels during treatment of peritoneal dialysis (PD)–associated peritonitis is controversial. Substantial inter-individual variability may result in suboptimal serum levels despite similar dosing of vancomycin. The published predictors of suboptimal serum vancomycin levels remain limited. Methods: Data were retrospectively collected from 541 patients on continuous ambulatory peritoneal dialysis between 1 January 2018 and 31 December 312019. For gram-positive cocci and culture-negative peritonitis, we adopted a vancomycin administration and monitoring protocol. Short-term adverse outcomes of PD-associated peritonitis, including transfer to haemodialysis, death, persistent infection beyond planned therapy duration and relapse, were observed. The association between trough serum vancomycin levels and short-term adverse outcomes was evaluated. Results: Intraperitoneal vancomycin was used in 61 gram-positive cocci or culture-negative peritonitis episodes in 56 patients. Fourteen episodes of short-term adverse outcomes occurred in 12 patients, whose average trough serum vancomycin levels on day 5 of treatment were significantly lower than those who didn’t experience any adverse outcomes (8.4 ± 1.7 vs 12.5 ± 4.3 mg/L, p = 0.003). In gram-positive cocci or culture-negative peritonitis patients, those with higher day 5 trough serum vancomycin levels had a lower risk of short-term adverse outcomes (odds ratio: 0.6, 95% confidence interval: 0.4 to 0.9, p = 0.011). Receiver operating charecteristic curve (ROC) analyses showed that the day 5 trough serum vancomycin levels diagnostic threshold value for short-term adverse outcomes was 10.1 mg/L. After adjustments for gender, exchange volume and residual kidney function (RKF), baseline higher peritoneal transport was associated with a suboptimal (<10.1 mg/L) day 5 serum vancomycin level. Conclusions: Serum vancomycin levels are correlated with short-term adverse outcomes of PD-associated peritonitis, and higher peritoneal solute transport status is associated with suboptimal trough serum vancomycin levels on day 5.

Persistence of live virus in critically ill patients infected with SARS-COV-2: a prospective observational study

Background Research on the duration of infectivity of ICU patients with COVID-19 has been sparse. Tests based on Reverse Transcriptase polymerase chain reaction (RT-PCR) detect both live virus and non-infectious viral RNA. We aimed to determine the duration of infectiousness based on viral culture of nasopharyngeal samples of patients with COVID-19. Methods Prospective observational study in adult intensive care units with a diagnosis of COVID-19 Pneumonia. Patients had repeated nasopharyngeal sampling performed after day 10 of ICU admission. Culture positive rate (based on viral culture on Vero cells in a level 4 lab) and Cycle threshold from RT-PCR were measured. Results Nine patients of the 108 samples (8.3%, 95% CI 3.9–15.2%) grew live virus at a median of 13 days (interquartile range 11–19) after their initial positive test. 74.1% of patients were RT-PCR positive but culture negative, and the remaining (17.6%) were RT-PCR and culture negative. Cycle threshold showed excellent ability to predict the presence of live virus, with a Ct < 25 with an AUC of 0.90 (95% CI 0.83–0.97, p < 0.001). The specificity of a Ct > 25 to predict negative viral culture was 100% (95% CI 70–100%). Conclusion 8.3% of our ICU patients with COVID-19 grew live virus at a median of 13 days post-initial positive RT-PCR test. Severity of illness, use of mechanical ventilation, and time between tests did not predict the presence of live virus. Cycle threshold of > 25 had the best ability to determine the lack of live virus in these patents.

Comparison Between Culture-Positive and Culture-Negative Septic Shock in Emergency Department Patients

Culture results in patients with septic shock affect their management strategies. Our study aimed to compare the clinical characteristics and outcomes of patients with culture-negative septic shock (CNSS) and culture-positive septic shock (CPSS). A single-center, retrospective, case-control study included adult patients diagnosed with septic shock in the emergency department between January 1, 2019 and March 31, 2020. They were divided into CNSS and CPSS groups based on their culture results. Patients with CPSS (63.7%, 311/488) and CNSS (36.3%, 177/488) were identified. The CPSS and CNSS groups had comparable clinical outcomes, including mechanical ventilation (29.6% vs. 32.8%, p = 0.46), renal replacement therapy (19.3% vs. 23.2%, p = 0.31), intensive care unit care (51.8% vs. 45.2%, p = 0.16), 30-day (35.7% vs. 36.7%, p = 0.82) and in-hospital mortality (39.5% vs. 41.8%, p = 0.63). The duration (13 [8−19] vs. 16 [10−23], days, p = 0.04) and de-escalation timing (5 [2−10] vs. 9 [7−12], day, p = 0.02) of antibiotic administration in the CNSS group was significantly shorter and earlier than in the CPSS group. Patients with CNSS and CPSS had similar clinical characteristics and adverse outcome proportions. Physicians can evaluate the feasibility of early de-escalation or discontinuation of antibiotic administration in CNSS patients with clinical improvement.

Should all patients with a culture-negative periprosthetic joint infection be treated with antibiotics?

Aims The aim of this study was to analyze the prevalence of culture-negative periprosthetic joint infections (PJIs) when adequate methods of culture are used, and to evaluate the outcome in patients who were treated with antibiotics for a culture-negative PJI compared with those in whom antibiotics were withheld. Methods A multicentre observational study was undertaken: 1,553 acute and 1,556 chronic PJIs, diagnosed between 2013 and 2018, were retrospectively analyzed. Culture-negative PJIs were diagnosed according to the Muskuloskeletal Infection Society (MSIS), International Consensus Meeting (ICM), and European Bone and Joint Society (EBJIS) definitions. The primary outcome was recurrent infection, and the secondary outcome was removal of the prosthetic components for any indication, both during a follow-up period of two years. Results None of the acute PJIs and 70 of the chronic PJIs (4.7%) were culture-negative; a total of 36 culture-negative PJIs (51%) were treated with antibiotics, particularly those with histological signs of infection. After two years of follow-up, no recurrent infections occurred in patients in whom antibiotics were withheld. The requirement for removal of the components for any indication during follow-up was not significantly different in those who received antibiotics compared with those in whom antibiotics were withheld (7.1% vs 2.9%; p = 0.431). Conclusion When adequate methods of culture are used, the incidence of culture-negative PJIs is low. In patients with culture-negative PJI, antibiotic treatment can probably be withheld if there are no histological signs of infection. In all other patients, diagnostic efforts should be made to identify the causative microorganism by means of serology or molecular techniques. Cite this article: Bone Joint J 2022;104-B(1):183–188.

Case Report: Metagenomics Next-Generation Sequencing for Diagnosing Cerebral Infarction and Infection Caused by Hematogenous Disseminated Mucormycosis in a Patient With Acute Lymphoblastic Leukemia

Disseminated mucormycosis, a serious complication, is associated with high mortality in patients with acute leukemia after chemotherapy. Blood cultures are always negative because of recurrent empirical antifungal treatments. The identification of pathogens is important for diagnosis and therapy. In this case report, we diagnosed culture-negative disseminated mucormycosis with Rhizomucor miehei infection leading to cerebral infarction in a patient with leukemia using metagenomics next-generation sequencing (mNGS) form peripheral blood, cerebral spinal fluid, and bronchoalveolar lavage fluid. mNGS technology can be applied to precisely diagnose culture-negative disseminated mucormycosis.

Evaluation of Real-Time Polymerase Chain Reaction in Culture-Negative Cerebrospinal Fluid Samples of Bacterial meningitis Patients

Background: Meningitis is a rigorous childhood disease with high morbidity and mortality. It is the main cause of under five mortality in India. Mainly three bacteria Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae are responsible. In low economic set up country like India, documented bacterial meningitis mainly depend on gram staining, cerebrospinal fluid (CSF) culture results or latex agglutination test resulting in less number of positive due to the prior antimicrobial intake which affects culture and latex agglutination test results. This study was taken up rapid and accurate molecular method like RT PCR to diagnose bacterial meningitis in culture-negative CSF samples. Materials and Methods: Fifty culture-negative CSF samples from suspected cases of bacterial meningitis were examined by real-time polymerase chain reaction (real-time PCR) for the presence of lytA, bexA, and ctrA genes specific for Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis respectively. Results: Positive real-time PCR results for Streptococcus pneumoniae were detected in 36 (72%) of culture-negative CSF samples while 10% positive results for Haemophilus influenzae type b. Nine (18%) samples were negative by real-time PCR for all tested organisms. Conclusion: The use of molecular techniques as real-time PCR can provide a valuable addition to the proportion of diagnosed cases of bacterial meningitis especially in settings with high rates of culture-negative results.