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Background and Aims. Bloodstream infections (BSIs) are one of the most frequently observed hospital-acquired infections (HAIs). We sought to describe the epidemiology and drug resistance secondary Enterobacterales BSIs in surgical patients and check for any correlation with the type of hospital ward. Materials and Methods. This multicenter (13 hospitals in southern Poland) laboratory-based retrospective study evaluated adults diagnosed with BSI secondary to surgical site infection (SSI) hospitalized in 2015–2018; 121 Enterobacterales strains were collected. The drug resistance was tested according to the EUCAST recommendations. Tests confirming the presence of extended-spectrum β-lactamases (ESBLs) and bla resistance genes were carried out. The occurrence of possible clonal epidemics among K. pneumoniae strains was examined. Results. The prevalence of Enterobacterales in secondary BSI was 12.1%; the most common strains were E. coli (n = 74, 61.2%) and Klebsiella spp. (n = 33, 27.2%). High resistance involved ampicillin and ampicillin/sulbactam (92, 8–100%), fluoroquinolones (48–73%), and most cephalosporins (29–50%). Carbapenems were the antimicrobials with the susceptibility at 98%. The prevalence of ESBL strains was 37.2% (n = 45). All the ESBL strains had blaCTX-M gene, 26.7% had the blaSHV gene, and 24.4% had blaTEM gene. The diversity of Klebsiella strains was relatively high. Only 4 strains belonged to one clone. Conclusions. What is particularly worrying is the high prevalence of Enterobacterales in BSI, as well as the high resistance to antimicrobial agents often used in the empirical therapy. To improve the effectiveness of empirical treatment in surgical departments, we need to know the epidemiology of both surgical site infection and BSI, secondary to SSI. We were surprised to note high heterogeneity among K. pneumoniae strains, which was different from our previous experience.

Background: Untreated staphylococcal ocular infections may cause injuries in the ocular structure and lead to visual impairments, lesions in the anatomical ocular surface, and blindness. The aim of the study was to describe the characteristic of 90 Staphylococcus aureus (SA) strains from hospital and community treated ocular infections with a special emphasis on ability of biofilm formation and drug resistance. The biofilm formation was carried out using the Congo red agar (CRA) method applying Congo red dye. Studies have demonstrated that the CRA method is simple, fast, and repeatable and that modifications of some components can easily increase its accuracy. Methods: Biofilm formation was examined by the method with CRA test. On CRA, slime-producing strains formed black colonies, whereas nonproducing strains developed red colonies in 6 kinds of colors, from very red to very black: very red, red, burgundy, almost black, black, and very black. Antimicrobial susceptibility testing was performed by disc diffusion or the E-test method according to the current guidelines of the EUCAST. The MRSA, and MLSB phenotypes were detected. Polymerase chain reaction (PCR) was used to detect the mecA, and mupA genes. Erythromycin resistance genes (ermA, ermB, ermC, and msr) were detected by multiplex PCR. Results: A positive result of the CRA test was accomplished in 66.2% cases; significantly more often in hospital strains (73.4% vs 45.4%; OR, 3.3; 55% CI, 1.2–9.3). Moreover, 73.4% isolates were fully susceptible. In hospitalized patients, the level of resistance to at least 1 antimicrobial category has been identified as 40.9%, and this rate was 27.2% in outpatients. Among the tested strains, 5 (6.0%) had the resistance phenotype MRSA and 22 (26.5%) the resistance phenotype MLSB; 4 strains manifested both mechanisms; erythromycin resistance was 25.3% in those resistant to fluoroquinolones. Resistance to fluoroquinolones was 5 times more often found in ambulatory patients. All of the tested isolates were vancomycin sensitive. Conclusions: Biofilm formation is an important risk factor for developmental staphylococcal hospital-acquired ocular infections. Our results prove that hospital strains have demonstrated much greater biofilm-forming ability than nonhospital strains. Studies indicate the high efficacy of chloramphenicol and fluoroquinolones treatments, as well as the need to implement new solutions due to the aforementioned bacteria’s high resistance to neomycin and anatomic barriers difficulties.Disclosures: NoneFunding: None

Background: Bloodstream infections (BSIs) are one of the most frequently observed hospital-acquired infections (HAIs). Objectives: We aimed to describe the epidemiology and drug resistance of hospital-acquired Enterobacteriaceae BSIs and to check for any correlation with the type of hospital care. Methods: In 2015–2018, 333 Enterobacteriaceae isolates were collected from hospitalized internal medicine and surgical patients. The drug-resistance testing was conducted according to the EUCAST recommendations, using the disc-diffusion method to determine resistance to penicillin, cephalosporins, carbapenems, aminoglycosides, fluoroquinolones, and sulfamethoxazole with trimethoprim. Tests confirming the presence of extended-spectrum β-lactamases (ESBLs) and KPC, NDM, and OXA-48 carbapenemases were performed. We determined the minimum inhibitory concentration (MIC) values (mg/L) for selected antibiotics. To detect the resistance genes, a single PCR reaction, a multiplex PCR, and a real-time PCR were conducted. Results: The prevalence rate of Enterobacteriaceae bacilli in BSIs was 23.5%. Penicillin resistance remained at a very high level of almost 100%, with only the piperacillin-tazobactam resistance remaining at 19%–22%. The same was true for cephalosporins: the bacilli have only shown a high susceptibility to cefoperazone with sulbactam (4%–14% of them were resistant). Ciprofloxacin (53%–62%) and sulfamethoxazole with trimethoprim (48–55%) have proven highly resistant. Carbapenems were the only antibiotics with susceptibility at 98%–99%. No difference was found between the types of hospital care (surgical vs nonsurgical) and the levels of antimicrobial resistance in the studied Enterobacteriaceae isolates (Table 1). Conclusions: The high prevalence of Enterobacteriaceae bacilli in BSI is particularly worrying, as is the high rate of resistance to cephalosporins and aminoglycosides, which are often used in the empirical therapy. Unfortunately, our results indicate the need to base the empirical therapy on carbapenems.Funding: This work was supported by a grant from Jagiellonian Univerity Medical School (No. N41/DBS/000053)Disclosures: None