High Potential For Dissemination Research Articles

Extended spectrum beta-lactamase-producing Enterobacteriaceae infections in hematopoietic stem cell transplant recipients: Epidemiology and molecular characterization

BackgroundExtended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) create a therapeutic challenge and have high potential for dissemination. The purpose of our study was to investigate the epidemiology of these infections in hematopoietic stem cell transplant (HSCT) recipients and to determine the genes encoding ESBL. Material/methodsThis retrospective study comprised adult patients hospitalized at the National Bone Marrow Transplant Center (NBMTC) and infected with ESBL-E post-HSCT between January 2006 and December 2016. The search for the ESBL and carbapenemase genes was performed by polymerase chain reaction (PCR) amplification. Molecular typing was performed by pulsed field gel electrophoresis (PFGE) after digestion with XbaI. ResultsForty ESBL-E were responsible for infections in 34 HSCT recipients (3.3% of total HSCT recipients). Prior hospital stay, prior antibiotic therapy and prior colonization with ESBL-E were reported in 62.5%, 70% and 50% of the infectious episodes, respectively. The initial antibiotic treatment was appropriate in 67.7% of cases. Imipenem was the most prescribed antibiotic (64.5%). The mortality rate due to ESBL-E infection was 8.8%.The ESBL-E, isolated mainly from blood cultures (40%), belonged mostly to K. pneumoniae (n=19) and E. coli (n=17). Associated antibiotic resistance rates were 17.5% for ertapenem, 85% for ciprofloxacin and 30% for amikacin. The predominant gene encoding ESBL was blaCTX-M (55%). Among the seven carbapenem-resistant strains, four had the blaOXA-48 gene and two the blaKPC gene. There was no clonal relationship between the strains. ConclusionThere was low prevalence of ESBL-E infections in HSCT recipients in our center, with no epidemic distribution but non-negligible mortality rate.

Program for lung cancer screening and tobacco cessation: Study protocol of a sequential, multiple assignment, randomized trial

PLUTO will conduct a sequential, multiple assignment, randomized trial to inform the choice and delivery of smoking cessation treatments for smokers in the setting of lung cancer screening, including for smokers who respond both incompletely (any smoking after quit date) and completely to first-line treatment (4 or 8 weeks of counseling with nicotine replacement therapy). Currently, there is little evidence to guide the development of adaptive interventions in tobacco cessation. SMART designs, such as the one we propose, are an ideal experimental design to assess different adaptive intervention strategies. Adaptive interventions for smoking cessation in the context of lung cancer screening have high potential for dissemination and impact. The USPSTF recommends annual low-dose CT screening for patients at high risk Recommendation (Grade B)4; private insurance coverage is mandated for USPSTF Grade A or B recommendations. The Affordable Care Act (ACA) mandates coverage of preventative services including smoking cessation treatment. The ACA requires coverage of at least 2 quit attempts/year, 4 counseling sessions of at least 10 minutes, and all Food and Drug Administration (FDA) approved tobacco cessation meds for a 90 day treatment regimen when prescribed by a health care provider (7 medications: 5 forms of NRT, bupropion, and varenicline).74 Effective smoking cessation treatment, delivered in the context of lung cancer screening programs, may augment the mortality benefit of imaging studies. The novel tobacco treatment system we plan – identification of smokers by using the EMR and proactive invitation to treatment coupled with lung cancer screening – is an opportunity to engage a new cohort of smokers with mechanisms in place to implement delivery of care. Thus, the PLUTO trial takes advantage of a new clinical practice development: recommendation for annual lung cancer screening based on age and smoking history. Strengths are an innovative study design and sequential random assignment of treatment conditions in addition to the main comparative effectiveness outcome that allows more rigorous measurement of effects than a standard randomized controlled trial would afford. The information about timing of assessment, optimal intervention components, and intensity of treatment are ripe for dissemination.

Abstract 3764: Targeting GPR64 in pediatric sarcomas with CAR transgenic T cells

Abstract Introduction: Ewing Sarcoma (ES) is the second most common bone malignancy in children and young adolescents with a high potential of dissemination into lung and bones. Patients with disseminated disease into the bone have an approximate long-term survival rate of only 10%, compelling the search for new therapeutic treatment modalities like engineered T cell therapy. Here the therapeutic potential of chimeric antigen receptor (CAR) transgenic T cells directed against G-protein coupled receptor 64 (GPR64) was examined. Experimental procedure: Two different monoclonal antibodies (mAb) directed against the extracellular region of GPR64 were generated and characterized. Subsequently, retroviral constructs containing second generation CARs together with the scFv fragments of the respective mAbs were designed. Constructs consisting of different spacers and co-stimulatory elements were compared (dIgG1-CD28-CD3z vs. CD8a-4-1BB-CD3z). Primary lymphocytes were transduced and tested in vitro via flow cytometry, ELISpot and xCelligence assay as well as in immunodeficient xenograft mice. Results: Antibodies specifically stained ES cells as determined by flow cytometry and immune histology. The signal intensity was reduced after RNAi mediated down-regulation of GPR64 in ES cell lines confirming specificity of the isolated mAbs. Following sequence determination of those mAbs two different CAR constructs were designed. Retroviruses containing such CARs transduced primary lymphocytes with high efficiency. The CAR transgenic T cells were enriched for CD8+CAR+ cells via microbead isolation and demonstrated strong proliferative capacities in vitro. Furthermore, target structures were specifically recognized as determined by ELISpot and xCelligence assays but dIgG1-CD28 CAR T cells derived from one hybridoma revealed hints of early exhaustion via auto-activation. Conclusion: CAR transgenic T cells targeting GPR64 show a promising approach to transfer the success of CARs in hematological malignancies to solid tumors. The cells generated in this study show strong specificity towards GPR64 and are able to control tumor cell growth. Since GPR64 expression is not restricted to ES but also up-regulated in a number of carcinomas derived from prostate, kidney or lung, GPR64-specific CARs may also be a future treatment option for other tumor entities. Citation Format: David Schirmer, Isabel Storz, Karin Wisskirchen, Regina Feederle, Oxana Schmidt, Hinrich Abken, Crystall Mackall, Ulrike Protzer, Stefan Burdach, Günther H. Richter. Targeting GPR64 in pediatric sarcomas with CAR transgenic T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3764. doi:10.1158/1538-7445.AM2017-3764

Dissemination of bla OXA-370 gene among several Enterobacteriaceae species in Brazil.

OXA-370 is a recently described OXA-48 variant that has only been described in a few Enterobacter spp. and Klebsiella pneumoniae isolates. The purpose of this study is to assess the prevalence of OXA-370-producing isolates in carbapenem-nonsusceptible Enterobacteriaceae recovered from 28 hospitals from Brazil. Real-time PCR was used to determine the presence of bla NDM-1, bla KPC-2, bla VIM-type, bla GES-type, bla OXA-48-like, and bla IMP-type genes. A total of 4,451 Enterobacteriaceae were screened. The gene bla OXA-48-like was detected in 74 (2.5%) isolates, mostly of Enterobacter spp. (44.6% E. cloacae and 2.7% E. aerogenes) and Klebsiella spp. (31.1% K. pneumoniae and 6.7% K. oxytoca), followed by Escherichia coli, (6.7%), Morganella morganii, (2.7%), Citrobacter freundii (1.3%), Proteus mirabilis (1.3%), Providencia stuartii (1.3%), and Serratia spp. (1.3%). These isolates were from five hospitals, 67 (90.5%) from the hospital where the bla OXA-370 was first described. Sequencing of bla OXA-48-like was performed in 52 isolates, including E. cloacae, E. aerogenes, K. pneumoniae, K. oxytoca, E. coli, and C. freundii; all presenting 100% identity with bla OXA-370. PFGE revealed the presence of distinct clones among K. pneumoniae, E. cloacae, K. oxytoca, and E. coli. Susceptibility rates to meropenem, imipenem, and ertapenem among OXA-370-producing isolates were 92.3%, 78.8%, 7.7% respectively; the MIC50 /MIC90 were 0.38/2mg/L and 1/3mg/L for meropenem and imipenem respectively. Overall, antimicrobial susceptibility analysis suggests that OXA-370 lacks carbapenemase activity. Our study demonstrated that the bla OXA-370 gene is disseminated among several Enterobacteriaceae species and clones, indicating a high potential for dissemination.

Carbapenemase-producing enterobacteriaceae recovered from a Spanish river ecosystem.

The increasing resistance to carbapenems is an alarming threat in the fight against multiresistant bacteria. The dissemination properties of antimicrobial resistance genes are supported by their detection in a diverse population of bacteria, including strains isolated from the environment. The objective of this study was to investigate the presence of carbapenemase-producing Enterobacteriaceae (CPE) collected from a river ecosystem in the Barcelona metropolitan area (Spain). Identification of β-lactamases and other resistance determinants was determined as was the antimicrobial susceptibility profile. Moreover, screening of virulence factors, plasmid addiction systems, plasmid partition systems and replicon typing was performed. The results identified 8 isolates belonging to different species (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Klebsiella oxytoca, Raoultella ornithinolytica). The most prevalent enzyme was KPC-2 (n = 6), followed by VIM-1 (n = 2) and IMI-2 (n = 1), whereas no OXA-48-type was detected. In addition, one strain was positive for both KPC-2 and VIM-1 enzymes. All the carbapenemase-encoding plasmids carried at least one plasmid addiction or partition system, being vagCD and parAB the most frequently detected, respectively. E. coli and K. pneumoniae isolates carried a low number of virulence-associated factors and none of the detected clones has previously been identified in the clinical setting. These findings support the high dissemination potential of the carbapanemase-encoding genes and reinforce the idea that the environment is another reservoir that may play an important role in the capture, selection and dissemination of carbapenem resistance genes.

Abstract B63: Therapeutic potential of GPR64 specific CAR T cells in pediatric sarcomas

Abstract Ewing Sarcoma (ES) is the second most common bone malignancy in children and young adolescents with a high potential of dissemination into lung and bones. Patients with localized disease receiving current treatment, have an approximate long-term survival of >65%. Patients with disseminated disease into the bone have an approximate long-term survival rate of only 10%, compelling the search for new therapeutic treatment modalities like engineered T cell therapy. Here the therapeutic potential of chimeric antigen receptor (CAR) transgenic T cells directed against G-protein coupled receptor 64 (GPR64), an orphan receptor with normal expression restricted to human epididymis and significant overexpression in ES, was examined. Therefore, two different monoclonal antibodies (mAb) directed against the extracellular region of GPR64 were generated and characterized. Subsequently, retroviral constructs containing second generation CARs together with the scFv fragments of the respective mAbs were designed. Primary lymphocytes were transduced and tested in vitro via flow cytometry, ELISpot and xCelligence assay. Antibodies specifically stained ES cells as determined by flow cytometry. The signal intensity was reduced after RNAi mediated down-regulation of GPR64 in ES cell lines confirming specificity of mAbs. Following sequence determination of those mAbs two different CAR constructs were designed. Retroviruses containing such CARs transduced primary lymphocytes with good efficiency. The CAR transgenic T cells could be enriched for CD8+CAR+ cells via microbead isolation and showed strong proliferative capacities in vitro. Furthermore, target structures were specifically recognized as determined by ELISpot and xCelligence assays. CAR transgenic T cells targeting GPR64 show a promising approach to transfer the success of CARs in hematological malignancies to solid tumors. The cells generated in this study show strong specificity towards GPR64 and are able to control tumor cell growth in vitro. Since GPR64 expression is not restricted to ES but also up-regulated in a number of carcinomas derived from prostate, kidney or lung, GPR64-specific CARs may also be a future treatment option for other tumor entities. Citation Format: Isabel Storz, David Schirmer, Karin Wisskirchen, Regina Feederle, Oxana Schmidt, Hinrich Abken, Ulrike Protzer, Stefan Burdach, Günther HS Richter. Therapeutic potential of GPR64 specific CAR T cells in pediatric sarcomas. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B63.

Abstract 1543: Clinical significance of ZNF185 intracellular localization in pancreatic ductal carcinoma

Abstract Pancreatic cancer is one of the most aggressive human tumors because of the challenges associated with detecting it at an early stage and its high potential for dissemination and distant metastasis. Therefore, clarifying the biological mechanisms underlying distant metastasis from pancreatic cancer and accelerating the development of new treatment strategies are needed. We previously isolated ZNF185, a metastasis-related protein, using a global quantitative proteome analysis. ZNF185 contains two zinc-finger motifs in the C-terminus that fit the consensus pattern of the LIM domains inducing tumor formation and cytoskeleton organization. In the present study, we investigated the expression of ZNF185 in human pancreatic cancer in vivo and in clinical cases, and also evaluated its prognostic significance. Immunohistochemical staining of resected specimens and a xenograft model of liver metastasis was used to examine the relationship between distant metastasis in and the prognosis of pancreatic cancer and the expression of ZNF185. Cells expressing ZNF185 in the plasma membrane were detected in 71 (39.0%) out of 182 patients with resected pancreatic cancer. Patients not expressing ZNF185 in the plasma membrane had a median survival of 30.2 months, whereas those expressing ZNF185 in the plasma membrane had a median survival of 21.3 months. A multivariate analysis indicated that the expression of ZNF185 in the plasma membrane was an independent poor prognostic factor (p = 0.016). A multivariate analysis indicated that patients with cells expressing ZNF185 in the plasma membrane were more likely to develop hematogenous metastasis (p = 0.081). NOD/Shi-scid/IL-2Rγnull(NOG) mice were used to compare the expression of ZNF185 in the subcutaneous tumors of the parent cell line BxPC-3 and liver metastatic tumors of the highly liver-metastatic subline LM-BxPC-3 established in our laboratory. Cells expressing ZNF185 in the plasma membrane were more prevalent in metastatic disease in the liver than in subcutaneous tumors, and these cells were often located at the tumor margins rather than in the center of the tumor. In conclusion, ZNF185 is a protein related to hematogenous metastasis, the expression of which in the plasma membrane was identified as an independent prognostic factor for pancreatic cancer. Citation Format: Daisuke Furukawa, Tsuyoshi Chijiwa, Masahiro Matsuyama, Masaya Mukai, Ei-ichi Matsuo, Osamu Nishimura, Kenji Kawai, Hiroshi Suemizu, Toshio Nakagohri, Seiei Yasuda, Kazuaki Shimada, Nobuyoshi Hiroka, Masato Nakamura. Clinical significance of ZNF185 intracellular localization in pancreatic ductal carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1543.

Dissemination of intramedullary anaplastic ependymomas

Two cases of 6 years old and 20 years of ages were operated for intramedullary anaplastic ependymomas. A gross total microsurgical excision of their tumors was achieved in both the cases, barring the infiltrated nerve roots of one case (6 years old, child). Standard doses of irradiation were offered to both the cases following surgery. The dissemination of disease occurred at six months and one year and 10 months duration in both. An extensive spread of ependymoma involved full spinal cord and brain stem in the first case, while malignant meningitis, mild hydrocephalus and a distal recurrence occurred in another case. It was concluded that (1) anaplastic ependymomas have high potential for dissemination anywhere in neuraxis (2) dissemination may occur without a local recurrence of tumor at primary site (3) gross total microsurgical excision and irradiation does not offer resistance to dissemination.

Cost-effectiveness Of A Mail-delivered Culturally And Linguistically Adapted Physical Activity Intervention For Latinas

PURPOSE: Latinos report high rates of inactivity and related conditions (diabetes, obesity). Costs of treating and managing these conditions have risen sharply, and Latinos have limited access to quality preventive care. It is therefore essential to develop interventions that not only increase physical activity (PA) in Latinos but do so in a cost-effective way with potential for broad dissemination. The objective of this study was to determine the costs and cost-effectiveness of a mail-delivered PA intervention for Latinas. METHODS: Seamos Saludables was a randomized controlled trial of 266 Latinas assigned to receive either print-based PA intervention materials individually tailored using expert system software (intervention) or wellness materials (control). Materials were delivered through the mail for six months, with maintenance doses and follow-up through 12 months. PA was measuring using the 7-Day Physical Activity Recall Interview. Costs were calculated from a clinical perspective, and included staff time (training and intervention delivery), hardware/software, materials, printing and postage. Research, measurement, and recruitment costs were not included. RESULTS: Intervention participants showed greater increases in PA than controls at six months (+71 minutes/week vs. +30 minutes/week) and 12 months (+94 minutes/week vs. +40 minutes/week). At six months, the cost to deliver the intervention per participant was $29/month in the intervention arm vs. $15/month in the control arm. These fell to $17 and $9 at 12 months, respectively. The cost-per-minute increase in PA at six months was $0.18 for the intervention vs. $0.23 for controls. These fell to $0.07 and $0.08 at 12 months. Overall, the incremental cost per minute of PA for the intervention relative to controls was $0.15/minute at 6 months and $0.05/minute at 12 months. CONCLUSIONS: The cost of delivering the intervention was roughly twice that of delivering the control. However, the intervention was more cost effective relative to change in PA behavior costing less per minute of PA increase than controls. Overall, the intervention proved relatively low cost, with a delivery channel of high potential for dissemination. A mail-delivered PA intervention, therefore, may be a cost effective approach to increasing PA in this at-risk population.

Carbapenemase-producing Gram-negative bacteria: current epidemics, antimicrobial susceptibility and treatment options.

Carbapenemases, with versatile hydrolytic capacity against β-lactams, are now an important cause of resistance of Gram-negative bacteria. The genes encoding for the acquired carbapenemases are associated with a high potential for dissemination. In addition, infections due to Gram-negative bacteria with acquired carbapenemase production would lead to high clinical mortality rates. Of the acquired carbapenemases, Klebsiella pneumoniae carbapenemase (Ambler class A), Verona integron-encoded metallo-β-lactamase (Ambler class B), New Delhi metallo-β-lactamase (Ambler class B) and many OXA enzymes (OXA-23-like, OXA-24-like, OXA-48-like, OXA-58-like, class D) are considered to be responsible for the worldwide resistance epidemics. As compared with monotherapy with colistin or tigecycline, combination therapy has been shown to effectively lower case-fatality rates. However, development of new antibiotics is crucial in the present pandrug-resistant era.

Dissemination and serotype modification potential of pSFxv_2, an O-antigen PEtN modification plasmid in Shigella flexneri

The O-antigens of all Shigella flexneri serotypes, except serotype 6, share a linear tetrasaccharide repeat composed of one N-acetylglucosamine and three l-rhamnose residues, and differences between the serotypes are due to modification of various monosaccharide residues with glucosyl and/or O-acetyl and/or phosphoethanolamine (PEtN) groups. Plasmid-borne opt (formerly lpt-O) gene encoding a PEtN transferase which modifies the O-antigens of S. flexneri serotype X, 4a and Y strains and converts the hosts into MASF IV-1 (E1037) positive "variant" (v) Xv, 4av and Yv serotypes, respectively. In this study, we showed that the opt-carrying plasmid pSFxv_2 can transform strains of all S. flexneri serotypes (1-6) to confer them with the MASF IV-1 epitope recognized by monoclonal antibody MASF IV-1 and typing antiserum IV. The transformants possessed modified O-antigens with a PEtN group(s) at position 3 of one or two rhamnose residues. In some serotypes, the PEtN modification competed or/and interfered with glucosylation and O-acetylation at the same or its neighboring sugar residue. We also showed that the plasmid pSFxv_2 is mobilizable to other S. flexneri strains by conjugation. Although pSFxv_2-harboring S. flexneri strains found in clinical infections are restricted to serotypes Xv, 4av, Yv and, possibly, 6v, our results demonstrate a high potential of dissemination of this plasmid in S. flexneri and emergence of new S. flexneri serotypes.

The CTX-M-15-Producing Escherichia coli Clone O25b: H4-ST131 Has High Intestine Colonization and Urinary Tract Infection Abilities

Increasing numbers of pyelonephritis-associated uropathogenic Escherichia coli (UPEC) are exhibiting high resistance to antibiotic therapy. They include a particular clonal group, the CTX-M-15-producing O25b:H4-ST131 clone, which has been shown to have a high dissemination potential. Here we show that a representative isolate of this E. coli clone, referred to as TN03, has enhanced metabolic capacities, acts as a potent intestine- colonizing strain, and displays the typical features of UPEC strains. In a modified streptomycin-treated mouse model of intestinal colonization where streptomycin was stopped 5 days before inoculation, we show that TN03 outcompetes the commensal E. coli strains K-12 MG1655, IAI1, and ED1a at days 1 and 7. Using an experimental model of ascending UTI in C3H/HeN mice, we then show that TN03 colonized the urinary tract. One week after the transurethral inoculation of the TN03 isolates, the bacterial loads in the bladder and kidneys were significantly greater than those of two other UPEC strains (CFT073 and HT7) belonging to the same B2 phylogenetic group. The differences in bacterial loads did not seem to be directly linked to differences in the inflammatory response, since the intrarenal expression of chemokines and cytokines and the number of polymorphonuclear neutrophils attracted to the site of inflammation was the same in kidneys colonized by TN03, CFT073, or HT7. Lastly, we show that in vitro TN03 has a high maximum growth rate in both complex (Luria-Bertani and human urine) and minimum media. In conclusion, our findings indicate that TN03 is a potent UPEC strain that colonizes the intestinal tract and may persist in the kidneys of infected hosts.

Infectividade natural por Xylella fastidiosa Wells et al. de cicadelíneos (Hemiptera: Cicadellidae) de lavouras cafeeiras do Paraná

Xylella fastidiosa Wells et al., a gram-negative and xylem limited bacterium, causes significative economic on several crops, such as the leaf scorch in coffee. It is transmitted by xylem feeding insects and four sharpshooters species have been reported as vectors of X. fastidiosa in coffee. The objective of this study was to determine the natural infectivity of X. fastidiosa in five species of sharpshooters from coffee trees: Acrogonia citrina Marucci & Cavichioli, Bucephalogonia xanthophis (Berg), Dilobopterus costalimai Young, Oncometopia facialis (Signoret) and Sonesimia grossa (Signoret). Samples were collected from coffee plantations in five counties of the North and Northwest regions of the State of Parana, Brazil, from October 1998 through November 2001. A total of 806 samples containing three to five insects were examined for the presence of X. fastidiosa by using PCR and nested PCR tests. X. fastidiosa was present in samples of all five species of sharpshooters collected in the two coffee regions. The average level of natural infectivity potential was 30.4%. However, this natural infectivity ranged from 2.2% for O. facialis to 68.8% for A. citrina. Sharpshooters collected in the spring tended to have lower natural infectivity of X. fastidiosa as compared to those collected in other seasons. The results obtained showed the high potential of dissemination of X. fastidiosa by different insect vectors in coffee trees in Parana.

Carbapenem-resistant strain of Klebsiella oxytoca harboring carbapenem-hydrolyzing beta-lactamase KPC-2.

We investigated a Klebsiella oxytoca isolate demonstrating resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The MICs of both imipenem and meropenem were 32 microg/ml. The beta-lactamase activity against imipenem and meropenem was inhibited in the presence of clavulanic acid. Isoelectric focusing studies demonstrated five beta-lactamases with pIs of 8.2 (SHV-46), 6.7 (KPC-2), 6.5 (unknown), 6.4 (probable OXY-2), and 5.4 (TEM-1). The presence of the bla(SHV) and bla(TEM) genes was confirmed by specific PCR assays and DNA sequence analysis. Transformation and conjugation studies with Escherichia coli showed that the beta-lactamase with a pI of 6.7, Klebsiella pneumoniae carbapenemase-2 (KPC-2), was encoded on an approximately 70-kb conjugative plasmid that also carried SHV-46, TEM-1, and the beta-lactamase with a pI of 6.5. The bla(KPC-2) determinant was cloned in E. coli and conferred resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The amino acid sequence of KPC-2 showed a single amino acid difference, S174G, when compared with KPC-1, another carbapenem-hydrolyzing beta-lactamase from K. pneumoniae 1534. Hydrolysis studies showed that purified KPC-2 hydrolyzed not only carbapenems but also penicillins, cephalosporins, and aztreonam. KPC-2 had the highest affinity for meropenem. The kinetic studies revealed that KPC-2 was inhibited by clavulanic acid and tazobactam. An examination of the outer membrane proteins of the parent K. oxytoca strain demonstrated that it expressed detectable levels of OmpK36 (the homolog of OmpC) and a higher-molecular-weight OmpK35 (the homolog of OmpF). Thus, carbapenem resistance in K. oxytoca 3127 is due to production of the Bush group 2f, class A, carbapenem-hydrolyzing beta-lactamase KPC-2. This beta-lactamase is likely located on a transposon that is part of a conjugative plasmid and thus has a very high potential for dissemination.

Selection of human ovarian carcinoma cells with high dissemination potential by repeated passage of the cells in vivo into nude mice, and involvement of Le(x)-determinant in the dissemination potential.

Cells of the human tumor cell line RMG‐1, derived from a clear‐cell adenocarcinoma of the ovary, were injected intraperitoneally into nude mice, and the cells obtained from the tumor nodules in the mesenterium were found to form a larger number of, and larger‐sized, tumor nodules than the original RMG‐1 cells. The RMG‐1‐h cells, transferred into culture from the tumor nodules after a 4th in vivo passage, showed a dissemination potential as high as that of cells disseminating directly from the tissues, and exceedingly higher than that of RMG‐1 cells. To assess the molecular bases of the different biological properties of RMG‐1 and RMG‐1‐h cells, we compared the content and expression of various carbohydrate antigens in both cells. The chromosomal profile of RMG‐1‐h cells revealed their human origin and was identical to that of the original RMG‐1 cells. In contrast to the broad histogram for the Lex‐bearing cells among RMG‐1 cells in flow cytometry, the weakly and moderately positive cells toward anti‐Lex antibody were found to be eliminated from the histogram for the RMG‐1‐h cells, resulting in the enrichment of cells strongly expressing Lex, which may account for the high dissemination potential. In addition, the adhesion of RMG‐1 cells to mesothelial cells was found to be significantly inhibited by pretreatment of the cells with anti‐Lex antibody, indicating Lex‐mediated cell‐to‐cell interaction between ovarian cancer cells and mesothelial cells. By TLC‐immunostaining, two Lex‐glycolipids, III3Fucα‐nLc4Cer and V3Fucα‐nLc6Cer were detected in both RMG‐1 and RMG‐1‐h cells, and their total concentrations were not significantly different from each other. However, the hydrophobic moieties of Lex‐glycolipids in RMG‐1‐h cells were different from those in RMG‐1 cells, suggesting that a difference in the structure of the hydrophobic moieties of Lex is partly involved in the enhanced reactivity of RMG‐1‐h cells toward anti‐Lex antibody. Thus, the high dissemination potential of ovarian cancer cells was shown to be mediated by the Lex‐determinant and the Lex‐bearing cells are enriched by repeated in vivo passage of the cells into nude mice.

Port-Site Recurrence of Cancer Associated With Laparoscopic Diagnosis and Resection: The European Experience

Port-site recurrences of cancer have drawn attention to the potential risks of laparoscopy for the diagnosis and treatment of digestive cancers. The first observations concerned unsuspected gallbladder cancers shown by laparoscopic cholecystectomy for lithiasis. Seventeen cases in patients with advanced or early colon cancer followed. It eventually became clear that all cancers could be the origin of such recurrences, which present as apparently isolated nodules embedded in the wall. These parietal recurrences were well known in open surgery, having been reported for most cancers, but they drew little attention because they usually occur in the context of carcinosis. It must be remembered that digestive cancers in general have a high potential for dissemination and that nearly 30% of patients have micrometastases in the bloodstream, the lymph nodes, the peritoneum, or even the bone marrow. The mechanism of tumor implantation is analogous to development of an inflammatory reaction. Under these conditions, laparoscopic surgery is susceptible to cause neoplastic dissemination for a number of mechanical reasons: CO2 insufflation, tumor manipulation, failure to isolate the tumor, forceful extraction of the surgical specimen, and exsufflation. Multiinstitutional trials of well-defined laparoscopic protocols based on the same oncologic principles as in open surgery should reduce the frequency of tumor cell dissemination and the incidence of port-site recurrences.

Port-Site Recurrence of Cancer Associated With Laparoscopic Diagnosis and Resection: The European Experience.

Port-site recurrences of cancer have drawn attention to the potential risks of laparoscopy for the diagnosis and treatment of digestive cancers. The first observations concerned unsuspected gallbladder cancers shown by laparoscopic cholecystectomy for lithiasis. Seventeen cases in patients with advanced or early colon cancer followed. It eventually became clear that all cancers could be the origin of such recurrences, which present as apparently isolated nodules embedded in the wall. These parietal recurrences were well known in open surgery, having been reported for most cancers, but they drew little attention because they usually occur in the context of carcinosis. It must be remembered that digestive cancers in general have a high potential for dissemination and that nearly 30% of patients have micrometastases in the bloodstream, the lymph nodes, the peritoneum, or even the bone marrow. The mechanism of tumor implantation is analogous to development of an inflammatory reaction. Under these conditions, laparoscopic surgery is susceptible to cause neoplastic dissemination for a number of mechanical reasons: CO2 insufflation, tumor manipulation, failure to isolate the tumor, forceful extraction of the surgical specimen, and exsufflation. Multiinstitutional trials of well-defined laparoscopic protocols based on the same oncologic principles as in open surgery should reduce the frequency of tumor cell dissemination and the incidence of port-site recurrences.

The sheep ked, Melophagus ovinus L. I. Dissemination potential.

Components of the intricate ked-sheep pattern, of significance in dissemination of the ked, are defined. It was found that the dissemination potential (percentage of population on the fleece surface) on one sheep was constantly greater than on a second. Bright sunshine caused an increase in the dissemination potential, particularly on the first sheep. It was concluded that the stimulating factor was a rise in the fleece temperature in regions directly exposed to the rays of the sun.The factor or factors causing differences in dissemination potential arose from similar degrees of temperature change being superimposed on inherently different fleeces. The sexes behaved similarly on both sheep.Keds were able to transfer readily between the two sheep. However, when they were concentrated on the sheep with a high dissemination potential, the population of the two-sheep system declined rapidly; when they were placed on the sheep with a low dissemination potential, the population of the two-sheep system increased. Approximately half of the keds leaving the sheep with a high dissemination potential did not reach a second host. It thus acted as a disinfecting agent.Bird and host predation were discounted as factors in causing ked population change.