The incidence of intestinal colonization of carbapenem-resistant Enterobacterales and its risk factors for bloodstream infection / 中华检验医学杂志

Objective:The aim of this study was to determine the colonization rate of carbapenem-resistant Enterobacterales (CRE) and identify the proportion and risk factors for bloodstream infection.Methods:This was a retrospective study conducted at the Department of Clinical Laboratory, Peking University People′s Hospital from January 2018 to December 2021. A total of 4 993 patients underwent rectal swab CRE screening for CRE, of which 137 were found to be positive. Clinical and laboratory data of the positive patients were collected, and the following parameters were analyzed: the positive rate of CRE screening in high-risk population, the species of colonized bacteria, antimicrobial resistance and the risk factors of CRE bloodstream infection in colonized patients. Statistical analysis was performed using SPSS 26.0 software. Univariate analysis was conducted using the chi-square (χ 2) test, while multivariate analysis was performed using binary logistic regression. The results were expressed as relative risk (odds ratio, OR) and 95% confidence interval ( CI). A significance level of 0.05 was considered statistically significant. The drug resistance rate of pathogen was analyzed by WHONET 5.6 software. Results:During the study period, a total of 4 991 patients who underwent rectal swab screening were eligible for inclusion, of which 137 patients were screened positive, resulting in a positive rate of 2.7% (137/4 991). The positive rates were higher in the intensive care ward and hematology ward, with rates of 5.5% (27/493) and 3.3% (109/3 321), respectively. A total of 145 colonization strains were isolated from patients with positive CRE screening, including 63 strains of Klebsiella pneumoniae (43.4%, 63/145), 52 strains of Escherichia coli (35.9%, 52/145), 16 strains of Enterobacter cloacae (11.0%, 16/145) and 14 strains of other Enterobacterales (9.7%, 14/145). The metal β-lactamase production type was the main component of CRE positive colonizing bacteria. The antimicrobial resistance of 145 strains to 22 antibacterial agents revealed that amikacin and tigacycline were the most sensitive. Among 137 CRE screening-positive patients, 14 (10.2%, 14/137) developed bloodstream infection. The isolated pathogenic bacteria included 10 Klebsiella pneumoniae strains and 4 Escherichia coli strains, with a predominant serine carbapenemase producing. Notably, the enzyme type and antimicrobial resistance of the bloodstream infection isolates in the same patient were highly consistent with those of the previous screening strains. Comparison was made between patients with positive CRE screening and those with CRE conversion to bloodstream infection. The unifactor analysis revealed significant differences in surgical history, neutropenia, hematopoietic stem cell transplantation, history of antibiotic use before rectal swab screening, screening within 48 hours after admission, and serine carbapenemase production by strains ( P<0.05). The multivariate analysis indicated that surgical history ( OR 24.659, 95% CI 2.540-239.411, P=0.006) and neutropenia ( OR 93.796, 95% CI 6.294-1 397.804, P=0.001) remained significantly associated with the risk of CRE bloodstream infection ( P<0.05). Conclusions:The CRE colonization rate was low in our hospital, but the proportion of patients with positive screening converted to bloodstream infection was high. Surgical history and neutropenia are risk factors for bloodstream infection transmission. Thus, it is essential to enhance monitoring in high-risk areas and susceptible patients.

Alarming prevalence of community-acquired multidrug-resistant organisms colonization in children with cancer and implications for therapy: A prospective study.

BACKGROUND: Infection or colonization with multidrug‑resistant organisms (MDRO) is associated with high mortality and morbidity. Knowledge of MDRO colonization may help in planning empirical antibiotic approach in neutropenic patients, which is known to improve patient outcomes. While routine cultures are positive and may help direct antibiotic therapy in only up to 15% neutropenic patients, surveillance cultures are positive in more than 90% of cancer patients. AIMS: To assess the rate of MDRO carrier status at presentation and rate of conversion to MDRO during the treatment. MATERIALS AND METHODS: Rectal swabs of all the outpatients presenting to pediatric oncology unit were sent within 7 days from date of registration from January 2014 to December 2014. Furthermore, stool cultures/rectal swabs of all patients who got directly admitted to the pediatric ward at presentation were sent within 24 h. Repeat rectal swabs were sent again for patients from this cohort when they got readmitted to the ward at least 15 days after last discharge or when clinically indicated. RESULTS: Baseline surveillance rectal swabs were sent for 618 patients, which included 528 children with hematological malignancies and 90 children with solid tumors. Forty‑five (7.3%) showed no growth. Of the remaining 573, 197 (34.4%) patients were colonized by two organisms and 30 (5.2%) by three organisms. Three hundred and thirty‑four (58.4%) showed extended spectrum beta‑lactamase (ESBL) Enterobacteriaceae, of which 165 (49.5%) were ESBL sensitive to beta‑lactam with beta‑lactamase inhibitors combinations and 169 (50.5%) were resistant to combinations. One hundred and sixteen (20.2%) were carbapenem‑resistant Enterobacteriaceae (CRE) and 65 (11.4%) had vancomycin‑resistant enterococci in baseline cultures. Only 63 (21%) patients were colonized by a sensitive organism in their baseline surveillance cultures. Morbidity (Intensive Care Unit stay) and mortality was higher in patients colonized by MDR organisms. There was a significant correlation between the place of residence and CRE colonization status with the highest rate (60%) of CRE colonization observed in children from East India. The repeat cultures showed the further conversion of sensitive isolates to MDRO in 80% of these children, of which 40% each converted from non‑ESBL and non‑CRE to ESBL and CRE, respectively. CONCLUSION: This is the first study illustrating the alarming high prevalence of community‑acquired MDRO colonization, especially CRE, which has grave implications for therapy for children with cancer potentially compromising delivery of aggressive chemotherapy and affecting outcomes. This incidence further increases during the course of treatment. Knowing the baseline colonization also guides us for the planning of chemotherapy as well as antibiotic approach and infection control strategies. Local antibiotics stewardship including education of the healthcare workers as well as national level interventions to prevent antibiotic misuse in the community is critical to minimize this problem.

Rates of Fecal Transmission of Extended-Spectrum beta-Lactamase-Producing and Carbapenem-Resistant Enterobacteriaceae Among Patients in Intensive Care Units in Korea

BACKGROUND: We investigated the rates of fecal transmission of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and carbapenem-resistant Enterobacteriaceae (CRE) among patients admitted to intensive care units (ICUs). METHODS: From June to August 2012, rectal cultures were acquired from all patients at ICU admission. For patients not carrying ESBL-E or CRE at admission, follow-up cultures were performed to detect acquisition. A chromogenic assay was used to screen for ESBL-E and CRE. Bacterial species identification and antibiotic susceptibility tests were performed using the Vitek 2 system (bioMerieux, France). ESBL genotypes were determined by PCR, and clonal relatedness of the isolates was assessed by pulsed-field gel electrophoresis. RESULTS: Out of 347 ICU admissions, 98 patients were found to be carriers of ESBL-E (28.2%, 98/347). Follow-up cultures were acquired from 91 of the patients who tested negative for ESBL-E at admission; the acquisition rate in this group was 12.1% (11/91), although none was a nosocomial transmission. For CRE, the prevalence of fecal carriage was 0.3% (1/347), and the acquisition rate was 2.9% (4/140). None of the CRE isolates were carbapenemase-producers. CONCLUSIONS: The high prevalence of ESBL-E carriage on admission (28.2%), coupled with rare nosocomial transmission and the very low carriage rate of CRE (0.3%), challenge the routine use of active surveillance in non-epidemic settings. Nevertheless, passive surveillance measures, such as rapid and accurate screening of clinical specimens, will be critical for controlling the spread of CRE.

Modified CHROMagar Acinetobacter Medium for Direct Detection of Multidrug-Resistant Acinetobacter Strains in Nasal and Rectal Swab Samples

This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37degrees C. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization.

Modified CHROMagar Acinetobacter Medium for Direct Detection of Multidrug-Resistant Acinetobacter Strains in Nasal and Rectal Swab Samples

This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37degrees C. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization.

Evaluation of a Newly Developed Multiplex Real-time PCR Assay for the Detection of Vancomycin-Resistant Enterococci from Rectal Swabs / 대한임상미생물학회지

BACKGROUND: Asymptomatic vancomycin-resistant enterococci (VRE) colonization precedes infection. VRE-colonized patients serve as silent reservoirs of enterococci that go on to colonize other patients. Rapidly identifying colonized patients is crucial to prevent the spread of VRE. The culture-based method of VRE screening is time-consuming. We evaluated the diagnostic performance of a recently developed multiplex real-time PCR for the detection of VRE. METHODS: We obtained 105 rectal swabs from patients who were being monitored for carriage of VRE. After 24 hour incubation of swabs in enterococcosel broth (EB) supplemented with 6 microg/mL vancomycin, multiplex real-time PCR was performed using the Anyplex(TM) VanR Real-time Detection (VanR) kit (Seegene, Inc., Seoul, Korea). The results of multiplex real-time PCR were compared to those of culture. We evaluated the specificity and detection limits of multiplex real-time PCR using VanR for VRE. RESULTS: A total of 96/105 (91.4%) samples were VRE positive according to multiplex real-time PCR with EB while 85/105 (80.9%) samples were positive in culture. Eleven discordant results (10.4%) (multiplex real-time PCR positive, culture negative) were noted. All non-enterococcal bacteria and vancomycin-susceptible enterococci were negative. The DNA detection limits of VanR were 0.035 pg per reaction (3 microL) for Enterococcus faecium and 0.35 pg for Enterococcus faecalis. CONCLUSION: The application of multiplex real-time PCR after EB incubation allows rapid and sensitive detection in 26-28 hours for VRE screening from rectal swabs. This method could facilitate the timely implementation of contact isolation to prevent the spread of VRE.