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Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.

ABSTRACT: Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant bacteria (MDR). In this study, the biofilm-forming capability of 209 MDR strains (Escherichia coli n?=?106, Klebsiella pneumoniae n?=?78, and Enterobacter spp. n?=?25) isolated from rectal swabs in the first 48?hours before or after kidney (93 patients), liver (60 patients) or kidney/pancreas transplants (5 patients) were evaluated by using a microplate assay. Thirty-nine strains were isolated before transplant and 170 strains were isolated post-transplant. Overall, 16% of E. coli strains, 73% of K. pneumoniae strains and 4% Enterobacter strains showed moderate or strong biofilm production. Nine strains isolated from infection sites after transplantation were responsible of infections in the first month. Of these, 4 K. pneumoniae, 1 E. coli and 1 Enterobacter spp. strains isolated pre-transplant or post-transplant as colonizers caused infections in the post-transplant period. Our results suggest that in vitro biofilm formation could be an important factor for adhesion to intestine and colonization in MDR K. pneumoniae strains in SOT recipients, but this factor appears to be less important for MDR E. coli and Enterobacter spp.

SUBMITTER: Ramos-Vivas J

PROVIDER: S-EPMC6586660 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.

Ramos-Vivas José J Chapartegui-González Itziar I Fernández-Martínez Marta M González-Rico Claudia C Fortún Jesús J Escudero Rosa R Marco Francesc F Linares Laura L Montejo Miguel M Aranzamendi Maitane M Muñoz Patricia P Valerio Maricela M Aguado Jose María JM Resino Elena E Ahufinger Irene Gracia IG Vega Aurora Paz AP Martínez-Martínez Luis L Fariñas María Carmen MC

Scientific reports 20190620 1

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant bacteria (MDR). In this study, the biofilm-forming capability of 209 MDR strains (Escherichia coli n = 106, Klebsiella pneumoniae n = 78, and Enterobacter spp. n = 25) isolated from rectal swabs in the first 48 hours before or after kidney (93 patients), liver (60 patients) or kidney/pancreas transplants (5 patients) were evaluated by using a microplate assay. Thirty-nine strains were i ...[more]

PMID: 31222089

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Project description:Enterobacteria species are common causes of hospital-acquired infections, which are associated with high morbidity and mortality rates. Immunocompromised patients such as solid organ transplant (SOT) recipients are especially at risk because they are frequently exposed to antibiotics in the course of their treatments. In this work, we used a collection of 106 Escherichia coli, 78 Klebsiella pneumoniae, 25 Enterobacter spp., and 24 Citrobacter spp. multidrug resistant strains isolated from transplant patients (hepatic, renal or renal/pancreatic) in order to examine their ability to adhere in vitro to HT-29 human colon cells, and to determine if some adhesive characteristics are associated with prevalence and persistence of these strains. A total of 33 E. coli (31%), 21 K. pneumoniae (27%), 7 Enterobacter spp. (28%), and 5 Citrobacter spp. (21%), adhered to the colon epithelial cells. Two main adherence patterns were observed in the four species analyzed, diffuse adherence, and aggregative adherence. Under transmission electronic microscopy (TEM), most bacteria lacked visible fimbria on their surface, despite their strong adherence to epithelial cells. None of the strains studied was able to induce any cytotoxic effect on HT-29 cells although some of them strongly colonizing both cells and glass coverslips at high density. Some of the strains failed to adhere to the epithelial cells but adhered strongly to the cover-slide, which shows that microscopy studies are mandatory to elucidate the adherence of bacteria to epithelial cells in vitro, and that quantitative assays using colony forming unit (CFUs) counting need to be supplemented with pictures to determine definitively if a bacterial strain adheres or not to animal cells in vitro. We report here, for the first time, the aggregative adherence pattern of two multidrug resistant (MDR) Citrobacter freundii strains isolated from human patients; importantly, biofilm formation in Citrobacter is totally dependent on the temperature; strong biofilms were formed at room temperature (RT) but not at 37°C, which can play an important role in the colonization of hospital surfaces. In conclusion, our results show that there is a great variety of adhesion phenotypes in multidrug-resistant strains that colonize transplanted patients.

Project description:BackgroundMultidrug-resistant Enterobacterales (MDR-E), including carbapenem-resistant and third-generation cephalosporin-resistant Enterobacterales (CRE, CefR-E), are major pathogens following solid organ transplantation (SOT).MethodsWe prospectively studied patients who underwent lung, liver, and small bowel transplant from February 2015 through March 2017. Weekly perirectal swabs (up to 100 days post-transplant) were cultured for MDR-E. Whole-genome sequencing (WGS) was performed on gastrointestinal (GI) tract-colonizing and disease-causing isolates.ResultsTwenty-five percent (40 of 162) of patients were MDR-E GI-colonized. Klebsiella pneumoniae was the most common CRE and CefR-E. Klebsiella pneumoniae carbapenemases and CTX-M were leading causes of CR and CefR, respectively. Thirty-five percent of GI colonizers developed MDR-E infection vs 2% of noncolonizers (P < .0001). The attack rate was higher among CRE colonizers than CefR-E colonizers (53% vs 21%, P = .049). GI colonization and high body mass index were independent risk factors for MDR-E infection (P ≤ .004). Thirty-day mortality among infected patients was 6%. However, 44% of survivors developed recurrent infections; 43% of recurrences were late (285 days to 3.9 years after the initial infection). Long-term survival (median, 4.3 years post-transplant) did not differ significantly between MDR-E-infected and MDR-E-noninfected patients (71% vs 77%, P = .56). WGS phylogenetic analyses revealed that infections were caused by GI-colonizing strains and suggested unrecognized transmission of novel clonal group-258 sublineage CR-K. pneumoniae and horizontal transfer of resistance genes.ConclusionsMDR-E GI colonization was common following SOT and predisposed patients to infections by colonizing strains. MDR-E infections were associated with low short- and long-term mortality, but recurrences were frequent and often occurred years after initial infections. Findings provide support for MDR-E surveillance in our SOT program.

Project description:BACKGROUND:Immunosuppressed solid organ transplant recipients [SOTRs] have elevated rates of certain rare cancers caused by viruses. Evaluating risk of rare cancers among SOTRs may provide etiological clues for additional cancers linked to poor immunity and viral infections. METHODS:We performed a cohort study of 262,455 SOTRs (1987-2014) from the US SOTR registry linked to 17 population-based cancer registries. First cancers in SOTRs were categorized using an established classification scheme based on site and histology. Standardized incidence ratios (SIRs) compared risk in SOTRs to the general population. We used Poisson regression to calculate incidence rate ratios (IRRs) according to immune-related SOTR characteristics, including time since transplant (i.e., duration of immunosuppression). All statistical tests are two-sided. RESULTS:We examined 694 distinct cancer subtypes, with 33 manifesting statistically significantly elevated SIRs (Bonferroni p?<?7.2 x 10-5). All 33 are rare (incidence <6 per 100,000 person-years) and several have known viral etiology (e.g. Merkel cell carcinoma (SIR = 24.7, 95%CI = 20.8 to 29.1). Additional cancers that were increased include squamous cell carcinomas (SCCs) of the lip (SIR range = 18.3-19.8), eye/adnexa (SIR = 13.8, 95%CI = 7.9 to 22.3), salivary gland (SIR = 9.3, 95%CI = 6.1 to 13.5), and nasal cavity/sinuses (SIR = 4.5, 95%CI = 2.8 to 6.8); sebaceous adenocarcinoma (SIR = 34.3, 95%CI = 26.3 to 44.0); malignant fibrous histiocytoma (15.4); and subtypes of bladder, kidney, lung, and colon cancer (SIR range = 3.2-13.3). Incidence of several cancers increased over time since transplant (ptrend<0.05), including SCCs of the lip, salivary gland, and anogenital sites. CONCLUSIONS:SOTRs experience elevated rates of several rare cancers. Because some of these cancers exhibit aggressive behavior with poor outcomes, it is important to further characterize the role of immunity and the potential involvement of oncogenic viruses to improve prevention and treatment.

Project description:Aeromonas hydrophila resides in a variety of aquatic environments. Infections with A. hydrophila mainly occur after contact with fresh or brackish water. Nosocomial infections with A. hydrophila can also occur. A. hydrophila infections can be difficult to treat due to both intrinsic and acquired antimicrobial resistance (AMR) mechanisms. In 2018-19, we isolated multi-drug resistant (MDR) A. hyrodphila from two solid organ transplant patients with intra-abdominal infections. We aimed to characterize their AMR mechanisms and to determine their genetic relatedness to aid epidemiological investigation. We performed whole genome sequencing (WGS) using Illumina MiSeq and Nanopore MinIon on 3 A. hydrophila isolates, with one isolate from Patient A (blood) and two isolates from Patient B (abdominal and T-tube fluid, isolated 2 weeks apart). Phenotypic assays included: Broth Microdilution (BMD), Modified Hodge Test (MHT), Modified Carbapenem Inactivation Method (mCIM), and EDTA Carbapenem Inactivation Method (eCIM). Data analyses were performed using CLCbio and Geneious. AMR genomic analysis revealed that all three isolates possess chromosomally encoded genes including bla OXA-12(oxacillinase), bla cepS (AmpC), and bla cphA7(metallo-beta-lactamase). All isolates tested strongly positive by MHT and mCIM, but only Patient B's second isolate (after 2 weeks of meropenem treatment) tested positive by eCIM. More intriguingly, Patient B's first isolate (before meropenem treatment) tested falsely susceptible to carbapenems by BMD, suggesting bla cphA7 gene was not expressed constitutively. Phylogenetic analysis showed the two isolates from Patient B were highly similar with only 1 SNP difference. The isolate from Patient A only differed from Patient B's isolates by 35 and 36 SNPs, respectively, suggesting close genetic relatedness. Further epidemiological investigation is undergoing. We report the first cases of CphA-mediated carbapenem resistant A. hydrophila in the U.S. It is concerning that 1 out of 3 isolates tested falsely susceptible to carbapenems by BMD despite clear carbapenemase production shown by strongly positive MHT and mCIM. In both cases, meropenem was initially used to treat the patients. Clinicians and microbiologists in the US should be aware of the emerging MDR Aeromonas nosocomial infections and the potential false carbapenem susceptible results due to CphA-type carbapenemase, which may be induced during treatment.

Dataset Information

Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.

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Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.

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