[Results of a multicenter study investigating plasmid mediated colistin resistance genes (mcr-1 and mcr-2) in clinical Enterobacteriaceae isolates from Turkey]. / Ülkemizde klinik Enterobacteriaceae izolatlarinda plazmit aracili kolistin direnç genlerini (mcr-1 ve mcr-2) arastiran çok merkezli çalismaya ait sonuçlar.

Colistin is a polymyxin antibiotic which is considered as one of the last line agents against infections due to multidrug resistant or carbapenem resistant gram-negative pathogens. Colistin resistance is associated with chromosomal alterations which can usually cause mutations in genes coding specific two component regulator systems. The first plasmid-mediated colistin resistance gene, mcr-1 was described in Escherichia coli and Klebsiella pneumoniae isolates in December 2015 and followed by another plasmid-mediated colistin resistance gene mcr-2 in 2016. The rapid and interspecies dissemination of plasmid-mediated resistance mechanisms through horizontal gene transfer, have made these genes considerably threatening. After the first reports, although mcr-1/mcr-2 producing Enterobacteriaceae isolates have been reported from many countries, there have been no reports from Turkey. Thus, the aim of this study was to investigate the presence of mcr-1/mcr-2 in clinical Enterobacteriaceae isolates from different parts of our country. A total of 329 Enterobacteriaceae isolates from 22 laboratories were collected which were isolated between March, 2015 and February, 2016. mcr-1/mcr-2 were investigated by polymerase chain reaction during February-March, 2016. Two hundred and seventeen of Klebsiella pneumoniae (66%), 75 of Salmonella spp. (22.8%), 31 of Esherichia coli (9.4%), 3 of Enterobacter cloacae (0.9%), 2 of Klebsiella oxytoca (0.6%) and 1 of Enterobacter aerogenes (0.3%) isolates were included to the study. Agarose gel electrophoresis results of PCR studies have shown expected band sizes for positive control isolates as 309 bp for mcr-1 and 567 bp for mcr-2. However, the presence of mcr-1/mcr-2 genes was not detected among the tested study isolates of Enterobacteriaceae. Although mcr-1/mcr-2 were not detected in our study isolates, it is highly important to understand the mechanism of resistance dissemination and determine the resistant isolates by considering that colistin is a last-line antibiotic against infections of multidrug or carbapenem resistant gram-negative bacteria. Thus, it is suggested that these mechanisms should be followed-up in both clinical and non-clinical (e.g. isolates from food animals, raw meats and environment) isolates of special populations.

Evaluation of Blood Cultures from SARS-CoV-2-Positive and Negative Adult Patients.

Bacteremia and fungemia are significant causes of morbidity and mortality that frequently occur as co-infections with viral respiratory infections, including SARS-CoV-2. The aim of this study was to evaluate the microorganisms that were isolated from the blood cultures of SARS-CoV-2-positive and negative patients and investigate their antimicrobial resistance patterns. A retrospective analysis was performed of 22,944 blood cultures sent to the laboratory between November 2020 and December 2021. Blood culture analyses were performed using the BD Bactec FX automated system. Identification was carried out using conventional methods, namely, VITEK-2 and MALDI-TOF MS. Antibacterial/antifungal susceptibility tests were performed according to EUCAST/CLSI recommendations. SARS-CoV-2 tests were performed with RT-PCR. Culture positivity was detected in 1630 samples from 652 patients. Of these 652 patients, 633 were tested for SARS-CoV-2; 118 (18.6%) were positive and 515 (81.3%) were negative. The bacteria and fungi that were isolated at the highest rate in SARS-CoV-2-positive patients were methicillin-resistant coagulase-negative staphylococci (MR-CoNS) (21.5%), Escherichia coli (12.4%), Klebsiella pneumoniae (12.4%), Candida albicans (1.65%), and Candida glabrata complex (1.65%), while in the negative patients, the highest rates were for E. coli (21.3%), MR-CoNS (13.5%), K. pneumoniae (12.05%), C. albicans (2.1%), Candida parapsilosis (1.1%), and Candida tropicalis (0.9%). No statistically significant difference was determined between COVID-19-positive and negative patients in terms of detection, such as with the Pseudomonas spp., Enterococcus spp., and methicillin-resistant Staphylococcus aureus isolated from the blood cultures (p > 0.05). The most common isolate was MR-CoNS in SARS-CoV-2-positive patients (p = 0.028). Acinetobacter baumannii was more frequent (p = 0.004) and carbapenem-resistant K. pneumoniae was isolated at a higher rate (60% vs. 43%) in SARS-CoV-2-positive patients compared to SARS-CoV-2-negative patients (p > 0.05). These findings highlight the fact that isolation procedures should not be disregarded and the distribution of bacterial/fungal agents of bloodstream infections and their antibiotic resistance should be followed up during a pandemic, such as in the case of COVID-19.

Impact of vancomycin-resistant enterococci colonization in critically ill pediatric patients.

BACKGROUND: We aimed to determine the frequency of vancomycin-resistant enterococci (VRE) infection occurrence in previously VRE-colonized children in a pediatric intensive care unit (PICU) and to identify associated risk factors. METHODS: Infection control nurses have performed prospective surveillance of health care-associated infections and rectal VRE carriage in PICUs from January 2010-December 2014. This database was reviewed to obtain information about VRE-colonized and subsequently infected patients. A case-control study was performed to identify risk factors associated with VRE infection development in previously VRE-colonized patients. RESULTS: Out of 1,134 patients admitted to the PICU, 108 (9.5%) were found to be colonized with VRE throughout the study period. Systemic VRE infections developed in 11 VRE-colonized patients (10.2%), and these included primary bloodstream infection (n = 6), urinary tract infection (n = 3), meningitis and bloodstream infection (n = 1), and meningitis (n = 1). Logistic regression analysis indicated long hospital stay (≥30 days) and glycopeptide use after detection of VRE colonization as risk factors for developing VRE infection in VRE-colonized patients (odds ratio [OR], 5.76; 95% confidence interval [CI], 1.6-15.8; P = .017 and OR, 12.8; 95% CI, 1.9-26.6; P = .012, respectively). CONCLUSIONS: VRE colonization has important consequences in pediatric critically ill patients. Strict infection control measures should be implemented to prevent VRE colonization and thereby VRE infections. Furthermore, irrational antibiotic use and particularly glycopeptide use in VRE-colonized patients should be restricted.

Vancomycin-resistant enterococci colonization in a neonatal intensive care unit: who will be infected?

OBJECTIVE: To determine the incidence of vancomycin-resistant enterococcus (VRE) colonization in our neonatal intensive care unit (NICU) over five-year period, rate of progression to VRE infection and associated risk factors. METHODS: A retrospective analysis of a prospective surveillance for VRE colonization and health care-associated infections was made. Contact precautions were taken against colonization, although the application varied over the years due to repairs in the unit. RESULTS: VRE rectal colonization was detected in 200/1671 neonates (12%) admitted to NICU. It showed great interannual variability from 1.9% to 30.3%. Sytemic VRE infection developed in 6/200 VRE-colonized patients (3%) within a median of 9 days (range: 3-58 days). The risk factors for VRE infection development identified in the univariate analysis were long hospital stay (≥30 days), necrotizing enterocolitis, surgical procedure, extraventricular drainage, receipt of amphotericin B and receipt of glycopeptides after detection of VRE colonization. Crude in-hospital mortality was higher in neonates who developed a systemic VRE infection (p < 0.001). CONCLUSION: Maintaining physical conditions in the unit favorable for infection control and rational use of antibiotics are essential in the control of VRE colonization and resultant infections. Special attention should be directed to VRE-colonized babies carrying the risk factors.