ABSTRACT
Background@#Ralstonia mannitolilytica is a causative organism of nosocomial infections, particularly associated with contaminated water, and resistant to various antibiotics, including carbapenems. Several clusters of R. mannitolilytica infections appeared in children at our institute from August 2018 to November 2019. @*Methods@#From March 2009 to March 2023, all patients admitted to Asan Medical Center Children’s Hospital in Seoul, Korea, with culture-confirmed R. mannitolilytica and corresponding clinical signs of infection were identified. Epidemiological and environmental investigations were conducted. Polymerase chain reaction (PCR) was performed for the genes of OXA-443 and OXA-444 on R. mannitolilytica isolates. @*Results@#A total of 18 patients with R. mannitolilytica infection were included in this study, with 94.4% (17/18) and 5.6% (1/18) being diagnosed with pneumonia and central line-associated bloodstream infection, respectively. All-cause 30-day mortality rate was 61.1% (11/18), and seven of the fatal cases were caused by R. mannitolilytica infection itself. The resistance rates to meropenem and imipenem werew 94.4% (17/18) and 5.6% (1/18), respectively. Although four out of nine meropenem-resistant R.mannitolilytica isolates had positive PCR results for OXA-443 and OXA-444 genes, there were no significant differences in antimicrobial susceptibility patterns. Environmental sampling identified R. mannitolylica at two sites: a cold-water tap of a water purifier and an exhalation circuit of a patient mechanical ventilator.After implementing and improving adherence to infection control policies, no additional R. mannitolilyticainfection cases have been reported since December 2019. @*Conclusion@#R. mannitolilytica can cause life-threatening infections with high mortality in fragile pediatric populations. To prevent outbreaks, healthcare workers should be aware of R. mannitolilytica infections and strive to comply with infection control policies.
ABSTRACT
Background@#Carbapenemase-producing Enterobacteriaceae (CPE) are highly drug-resistant pathogens. Screening the contacts of newly-identified CPE patients is crucial for nosocomial transmission control. We evaluated the acquisition rate of CPE in close contacts as a function of CPE genotype. @*Materials and Methods@#This study was conducted in Asan Medical Center, a 2,700-bed, tertiary teaching hospital in Seoul, Korea, between November 2010 and October 2017. Index cases were defined as patients with positive tests for CPE from any infected or colonized site during hospitalization who had no direct epidemiologic linkage with existing CPE patients; close contact patients were defined as those whose hospital stay overlapped with the stay of an index case for at least one day and who occupied the same room or intensive care unit (ICU). Secondary patients were defined as those who produced positive CPE culture isolates from surveillance cultures that had the same CPE enzyme as that of the index case patients. @*Results@#A total of 211 index case patients and 2,689 corresponding contact patients were identified. Of the contact patients, 1,369 (50.9%) including 649 New-Delhi metallo-betalactamase-1 (NDM-1) and 448 Klebsiella pneumoniae carbaepenamse (KPC)-producing CPE exposures were screened, and 44 secondary patients (3.2%; 95% confidence interval 2.3 -4.3%) were positive for NDM-1-producing CPE (16 patients) and KPC-producing (24 patients) CPE. The CPE acquisition rate (5.4%) for KPC-producing CPE exposures was significantly higher than that for NDM-1 exposures (2.7%) (P = 0.01). @*Conclusion@#The CPE acquisition rate was 3.2% among close contacts sharing a multi-patient room, with about a two-fold higher risk of KPC-producing CPE than NDM-1-producing CPE.
ABSTRACT
Cortex mori (Morus alba L.: Sangbaikpi), the root bark of mulberry tree, has been used as an antiphlogistic, diuretic, and expectorant in herbal medicine. Previous studies have demonstrated that the phenolic extract of Cortex mori have hypotensive, hypoglycemic, antifungal, antiviral, antiinflammatory, and anticancer effects, and the hot water extract from Cortex mori has inhibitory effects on compound 48/80- induced mast cell degranulation and histamine release from rat peritoneal mast cells (RPMCs). This study was perforrned to investigate the effects of polysaccharide fraction from Cortex mori (PFCM) on compound 48/80-induced degranulation, histamine release, calcium influx, changes of intracellular cAMP and cGMP level, and morphological changes of RPMCs. The results were summarized as follows. 1) Compound 48/80-induced cytomorphological changes such as swelling, degranulation, intracellular vacuoles, and interrupted cell boundary were significantly inhibited by pretreatment with either hot water or polysaccaride fractions frorn Cortex mori (PFCM), 2) the compound 48/80-induced histamine release from RPMCs pretreated with PFCM was significantly inhibited, compared to that of control without PFCM pretreatment, 3) the PFCM inhibited remarkably the compound 48/80-induced calcium influx into the RPMCs, 4) the PFCM increased significantly the intracellular cAMP levels and decreased the intracellular cGMP levels of RPMCs, compared to those of normal control, and 5) the compound 48/80-induced cAMP levels of RPMCs pretreated with PFCM were significantly increased, compared to those of positive control without PFCM, and the compound 48/80-induced cGMP levels of RPMCs pretreated with PFCM were remarkably decreased, compared to those of positive control without PFCM. From the above results, it is suggested that PFCM have an activity to inhibit the compound 48/80-induced mast cell activation.