Multidrug Resistance Status Research Articles

No Clinical Benefit of Empirical Antimicrobial Therapy for Pediatric Diarrhea in a High-Usage, High-Resistance Setting.

Pediatric diarrheal disease presents a major public health burden in low- to middle-income countries. The clinical benefits of empirical antimicrobial treatment for diarrhea are unclear in settings that lack reliable diagnostics and have high antimicrobial resistance (AMR). We conducted a prospective multicenter cross-sectional study of pediatric patients hospitalized with diarrhea containing blood and/or mucus in Ho Chi Minh City, Vietnam. Clinical parameters, including disease outcome and treatment, were measured. Shigella, nontyphoidal Salmonella (NTS), and Campylobacter were isolated from fecal samples, and their antimicrobial susceptibility profiles were determined. Statistical analyses, comprising log-rank tests and accelerated failure time models, were performed to assess the effect of antimicrobials on disease outcome. Among 3166 recruited participants (median age 10 months; interquartile range, 6.5-16.7 months), one-third (1096 of 3166) had bloody diarrhea, and 25% (793 of 3166) were culture positive for Shigella, NTS, or Campylobacter. More than 85% of patients (2697 of 3166) were treated with antimicrobials; fluoroquinolones were the most commonly administered antimicrobials. AMR was highly prevalent among the isolated bacteria, including resistance against fluoroquinolones and third-generation cephalosporins. Antimicrobial treatment and multidrug resistance status of the infecting pathogens were found to have no significant effect on outcome. Antimicrobial treatment was significantly associated with an increase in the duration of hospitalization with particular groups of diarrheal diseases. In a setting with high antimicrobial usage and high AMR, our results imply a lack of clinical benefit for treating diarrhea with antimicrobials; adequately powered randomized controlled trials are required to assess the role of antimicrobials for diarrhea.

Effect of prophylactic cefalexin treatment on the development of bacterial infection in acute radiation-induced dermatitis in dogs: a blinded randomized controlled prospective clinical trial.

Acute radiation-induced dermatitis (ARID) is a common sequela of radiation therapy and carries the risk of secondary bacterial skin infection. No standard of care exists for managing canine ARID and evidence-based guidelines are lacking; however, prophylactic use of antibiotics is common. To evaluate the impact of prophylactic cefalexin on the prevalence and severity of bacterial infection in canine ARID. Seventeen dogs treated with definitive-intent radiotherapy. All dogs were treated with definitive-intent radiation therapy (48-57.5 gray) targeted to the skin surface. Dogs were randomized to receive either prophylactic cefalexin (22 mg/kg twice daily) beginning halfway through the prescribed radiotherapy course (cohort A) or to serve as controls (cohort B). Aerobic skin cultures and surface cytological evaluation were performed at first onset of moist desquamation and one week following completion of radiation therapy. Skin toxicity grading and owner quality of life (QoL) questionnaires were performed weekly. The rate of infection, multidrug resistance status, toxicity severity and QoL between cohorts were compared. Staphylococcus schleiferi and S. pseudintermedius were the most frequent bacterial agents isolated in both cohorts. There was no significant difference in prevalence of bacterial infection or overall QoL between cohorts at either time point; however, multidrug-resistant infections were significantly increased in cohort A versus cohort B. Clinician- and client-perceived severity of toxicity was significantly greater and median duration of moist desquamation was significantly longer in cohort A than cohort B. Prophylactic use of cefalexin for management of canine ARID is not recommended.

Outcome of neurological early rehabilitation patients carrying multi-drug resistant bacteria: results from a German multi-center study

BackgroundColonization or infection with multi-drug resistant (MDR) bacteria is considered detrimental to the outcome of neurological and neurosurgical early rehabilitation patients.MethodsIn a German multi-center study, 754 neurological early rehabilitation patients were enrolled and and reviewed in respect to MDR status, length of stay (LOS) and the following outcome variables: Barthel Index (BI), Early Rehabilitation Index (ERI), Glasgow Outcome Score Extended (GOSE), Coma Remission Scale (CRS), Functional Ambulation Categories (FAC).ResultsThe mean age of the study population was 68.0 ± 14.8 years. Upon admission, the following prevalence for MDRs was observed: MRSA (methicillin resistant staphylococcus aureus) 7.0% (53/754), ESBL- (extended spectrum beta-lactamase) producing bacteria strains 12.6% (95/754), VRE (vancomycin resistant enterococci) 2.8% (21/754). Patients colonized or infected with MDR bacteria (MDR+) were significantly more frequently diagnosed with a critical illness polyneuropathy – CIP – than non-colonized (MDR-) patients: 29.0% vs. 14.8%. In addition, they were more frequently mechanically ventilated (MDR+: 55/138, 39.9%; MDR- 137/616, 22.2%). MDR+ patients were referred to rehabilitation earlier, had a longer LOS in early rehabilitation, lower BI on admission and at discharge, lower ERI on admission and lower CRS at discharge than MDR- patients. There was a highly significant correlation of the BI upon admission with the BI at discharge (rs = 0.492, p < 0.001). GOSE at discharge differed significantly between both groups (χ2-test, p < 0.01). Perhaps of greatest importance, mortality among MDR+ was higher in comparison to MDR- (18.1% vs. 7.6%).ConclusionsThe outcome of neurological early rehabilitation patients colonized or infected with MDR bacteria including MRSA or ESBL producing strains is significantly poorer than by non-colonized patients. There is some evidence that the poor outcome could be related to the higher morbidity and lower functional status upon admission.

Increased Costs Associated with Bloodstream Infections Caused by Multidrug-Resistant Gram-Negative Bacteria Are Due Primarily to Patients with Hospital-Acquired Infections.

The clinical and economic impacts of bloodstream infections (BSI) due to multidrug-resistant (MDR) Gram-negative bacteria are incompletely understood. From 2009 to 2015, all adult inpatients with Gram-negative BSI at our institution were prospectively enrolled. MDR status was defined as resistance to ≥3 antibiotic classes. Clinical outcomes and inpatient costs associated with the MDR phenotype were identified. Among 891 unique patients with Gram-negative BSI, 292 (33%) were infected with MDR bacteria. In an adjusted analysis, only history of Gram-negative infection was associated with MDR BSI versus non-MDR BSI (odds ratio, 1.60; 95% confidence interval [CI], 1.19 to 2.16; P = 0.002). Patients with MDR BSI had increased BSI recurrence (1.7% [5/292] versus 0.2% [1/599]; P = 0.02) and longer hospital stay (median, 10.0 versus 8.0 days; P = 0.0005). Unadjusted rates of in-hospital mortality did not significantly differ between MDR (26.4% [77/292]) and non-MDR (21.7% [130/599]) groups (P = 0.12). Unadjusted mean costs were 1.62 times higher in MDR than in non-MDR BSI ($59,266 versus $36,452; P = 0.003). This finding persisted after adjustment for patient factors and appropriate empirical antibiotic therapy (means ratio, 1.18; 95% CI, 1.03 to 1.36; P = 0.01). Adjusted analysis of patient subpopulations revealed that the increased cost of MDR BSI occurred primarily among patients with hospital-acquired infections (MDR means ratio, 1.41; 95% CI, 1.10 to 1.82; P = 0.008). MDR Gram-negative BSI are associated with recurrent BSI, longer hospital stays, and increased mean inpatient costs. MDR BSI in patients with hospital-acquired infections primarily account for the increased cost.

Global Assessment of the Activity of Tigecycline against Multidrug-Resistant Gram-Negative Pathogens between 2004 and 2014 as Part of the Tigecycline Evaluation and Surveillance Trial.

Multidrug-resistant (MDR) Gram-negative organisms are a burden on the global health care system. The Tigecycline Evaluation and Surveillance Trial (TEST) is an ongoing global study designed to monitor the in vitro activities of tigecycline and a panel of marketed antimicrobials against a range of clinically significant pathogens. In this study, in vitro data are presented for MDR Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, and Enterobacter cloacae isolates collected from 2004 to 2014. In total, 13% (21,967/170,759) of isolates displayed multidrug resistance globally, with the highest rates recorded among A.baumannii (overall rate, 44% [8,294/18,741], increasing from 23% [309/1,323] in 2004 to 63% [447/712] in 2014). Other multidrug resistance rates ranged from 2.5% for K.oxytoca (203/8,000) to 12% for P.aeruginosa and K.pneumoniae (3,951/32,786 and 3,895/32,888, respectively), and rates among these pathogens remained stable during the study period. Against MDR E.coli, Klebsiella spp., and E.aerogenes, the lowest rates of resistance were to tigecycline (0.2%, 6%, and 12%, respectively), and the lowest MIC90 value against A.baumannii was observed for tigecycline (2mg/liter; MIC range, ≤0.008 to ≥32mg/liter). The only significant change in resistance to tigecycline during the study period was for MDR E.coli (P < 0.01), among which eight resistant isolates were identified globally from 2009 to 2013. In summary, these results show that tigecycline retained in vitro activity against the majority of MDR Gram-negative organisms presented here, but the rising rates of MDR A.baumannii highlight the need for the continued monitoring of global multidrug resistance. IMPORTANCE Multidrug resistance among bacterial pathogens is an ongoing global problem and renders antimicrobial agents ineffective at treating bacterial infections. In the health care setting, infections caused by multidrug-resistant (MDR) Gram-negative bacteria can cause increased mortality, longer hospital stays, and higher treatments costs. The aim of the Tigecycline Evaluation and Surveillance Trial (TEST) is to assess the in vitro antimicrobial activities of tigecycline and other contemporary agents against clinically relevant pathogens. This paper presents antimicrobial activity data from the TEST study between 2004 and 2014 and examines global rates of MDR Gram-negative isolates, including Acinetobacter baumannii, Pseudomonas aeruginosa, and members of the Enterobacteriaceae, during this time. Our results show that tigecycline retained in vitro activity against many MDR Gram-negative pathogens over the study period, while rates of MDR A.baumannii increased globally. Using these findings, we hope to highlight the current status of multidrug resistance in medical facilities worldwide.

Surveillance of Gram-negative bacteria: impact of variation in current European laboratory reporting practice on apparent multidrug resistance prevalence in paediatric bloodstream isolates

This study evaluates whether estimated multidrug resistance (MDR) levels are dependent on the design of the surveillance system when using routine microbiological data. We used antimicrobial resistance data from the Antibiotic Resistance and Prescribing in European Children (ARPEC) project. The MDR status of bloodstream isolates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was defined using European Centre for Disease Prevention and Control (ECDC)-endorsed standardised algorithms (non-susceptible to at least one agent in three or more antibiotic classes). Assessment of MDR status was based on specified combinations of antibiotic classes reportable as part of routine surveillance activities. The agreement between MDR status and resistance to specific pathogen–antibiotic class combinations (PACCs) was assessed. Based on all available antibiotic susceptibility testing, the proportion of MDR isolates was 31% for E. coli, 30% for K. pneumoniae and 28% for P. aeruginosa isolates. These proportions fell to 9, 14 and 25%, respectively, when based only on classes collected by current ECDC surveillance methods. Resistance percentages for specific PACCs were lower compared with MDR percentages, except for P. aeruginosa. Accordingly, MDR detection based on these had low sensitivity for E. coli (2–41%) and K. pneumoniae (21–85%). Estimates of MDR percentages for Gram-negative bacteria are strongly influenced by the antibiotic classes reported. When a complete set of results requested by the algorithm is not available, inclusion of classes frequently tested as part of routine clinical care greatly improves the detection of MDR. Resistance to individual PACCs should not be considered reflective of MDR percentages in Enterobacteriaceae.

Profiling gene mutations, translocations, and multidrug resistance in pediatric acute lymphoblastic leukemia: a step forward to personalizing medicine.

Precise risk stratification and tailored therapy in acute lymphoblastic leukemia (ALL) can lead to enhanced survival rates among children. Translocations and mutations along with multidrug resistance markers are important factors that determine therapeutic efficacy. Gene mutation profiling of patients at the time of diagnosis can offer accurate clinical decision-making. Multiplex PCR was used to screen for various translocations, mutations, and P-glycoprotein (P-gp) status in pediatric ALL samples. The roles of P-gp were analyzed at the transcriptional and translational levels by using real-time PCR and immunoblotting, respectively. ALL specific cell line Jurkat was used to validate the functional role of P-gp in imparting drug resistance by siRNA knockdown studies. Co-occurrence of translocations and mutations contributes to cellular drug resistance. Presence of any translocation in addition to FLT3/ITD hints for overactive P-gp. Co-occurrence of E2A/PBX and TEL/AML has also been positively correlated with P-gp status. Multiplex PCR provides a rapid and cost effective technique for profiling translocations, mutations, and multidrug resistance status that determines what therapy patients could be administered. Mutation profiling in patients for analyzing genetic lesions along with drug resistance profiling will help improve risk stratification and personalized medicine, thereby increasing the treatment success rates among pediatric patients with leukemia.

Drug Susceptibility pattern of Organisms Isolated During Acute Exacerbation of Chronic Obstructive Pulmonary Disease in a Tertiary Level Hospital of Nepal

Introduction: Disease process in chronic obstructive lung disease is interrupted by acute exacerbations. Bacterial and viral infections account for majority of cases. Gram positive and Gram negative organism both are associated with exacerbations. Methods: Sputum samples were collected from COPD patients in acute exacerbation, on the day of emergency visit. Drug susceptibility pattern was evaluated for the study population to identify the prevalence of susceptible and resistant organisms. Results: Eighty-nine culture positive sputum samples were processed for drug susceptibility. Gram negative bacilli (88.76%) were isolated more than Gram positive cocci (11.24%). Pseudomonas sp., Acinetobacter sp., Klebseilla sp. and E. coli were the most common Gram negative bacilli. Multi-drug resistance status was identified in higher percents in Acinetobacter sp. (81.25%), Pseudomonas sp. (62.5%) and Klebseilla sp. (46.6%). Aminoglycosides and Quinolones showed good sensitivity to GNBs. However, Carbapenems were found to be the most effective agents against these organisms. Conclusion: Gram negative infection is common in COPD. Multi drug resistant pathogens are increasingly associated with acute exacerbations. Routinely used antibiotics are becoming less effective.

Drug susceptibility pattern in organisms isolated during acute exacerbation of Chronic Obstructive Pulmonary Disease

&lt;p&gt;Abstract&lt;/p&gt;&lt;p&gt;Introduction&lt;/p&gt;&lt;p&gt;Disease process in chronic obstructive lung disease is interrupted by acute exacerbations. Bacterial and viral infections accounts for majority of cases. Gram positive and Gram Negative organism are both associated.&lt;/p&gt;&lt;p&gt;Materials and Methods&lt;/p&gt;&lt;p&gt;Sputum samples were collected from COPD patients in acute exacerbation, on the day of emergency visit. Drug susceptibility pattern was evaluated for the study population to identify the prevalence of susceptible and resistant organisms.&lt;/p&gt;&lt;p&gt;Results&lt;/p&gt;&lt;p&gt;Eighty-nine culture positive sputum samples were processed for drug susceptibility. Gram negative bacilli (88.76%) were isolated more than Gram positive cocci (11.24%).&lt;em&gt; Pseudomonas sp.&lt;/em&gt;, &lt;em&gt;Acinetobacter sp.&lt;/em&gt;, &lt;em&gt;Klebseilla sp.&lt;/em&gt; and &lt;em&gt;E. coli&lt;/em&gt; were the most common Gram negative bacilli. Multi-drug resistance status was identified in higher percents in &lt;em&gt;Acinetobacter sp&lt;/em&gt;. (81.25%), &lt;em&gt;Pseudomonas sp&lt;/em&gt;. (62.5%) and &lt;em&gt;Klebseilla&lt;/em&gt; sp. (46.6%). Aminoglycosides and Quinolones showed good sensitivity to GNBs. However, Carbapenems were found to be the most effective agents against these organisms.&lt;/p&gt;&lt;p&gt;Conclusion&lt;/p&gt;&lt;p&gt;Gram negative infection is common in COPD. Multi drug resistant pathogens are increasingly associated with acute exacerbations. Routinely used antibiotics are becoming less effective.&lt;/p&gt;

Human Tuberculosis II. M. tuberculosis Mechanisms of Genetic and Phenotypic Resistance to Anti-Tuberculosis Drugs.

The great progress of knowledge of both M. tuberculosis physiology and how human host and bacilli interact has provided fertile ground for improving diagnosis and cure of TB infection. Once M. tuberculosis has infected humans, it elaborates strategies for evading the risk to killing by the cells of the host immune system and by the anti-tuberculosis (anti-TB) agents employed to cure infection. These strategies give rise to a bacterial multidrug resistance (MDR) status. This stems firstly from genetic mutations targeting a constellation of drug-processing mechanisms that still need full identification, as drug efflux pumps and drug activating/ inactivating enzymes (genetic resistance). Secondly, from the bacterial adaptation to stressful environmental conditions by adopting a temporary dormancy state lasting for decades and characterized by indifference to anti-TB drugs (phenotypic resistance or tolerance). The clarification of the strategies elaborated for surviving by M. tuberculosis has brought to the identification in the last few years of a number of mycobacterial molecular targets worth to exploitation for the development of novel and powerful anti-TB drugs. These targets include drug-efflux pump systems, considered partly responsible for genetic multi-drug resistance, and several enzymes and pump systems, as well, that sustain the metabolic adaptations of M. tuberculosis in the host and give rise to its phenotypic drug resistance.

SGN-CD123A, a Pyrrolobenzodiazepine Dimer Linked Anti-CD123 Antibody Drug Conjugate, Demonstrates Effective Anti-Leukemic Activity in Multiple Preclinical Models of AML

Survival expectations for acute myeloid leukemia (AML) patients remain poor, highlighting the need for further treatment options. The majority of AML blasts express CD123, the alpha subunit of the IL-3 receptor, which regulates the proliferation, survival and differentiation of hematopoietic cells. CD123 is also robustly expressed on leukemic stem cells and is a marker for minimal residual disease (MRD, Roug et al. 2012). Poor prognosis has previously been associated with elevated expression of CD123 on leukemic stem cells and blasts (Vergez et al. 2011, Testa et al. 2002). These findings identify CD123 as a rational therapeutic target in AML.Here we report the preclinical development of a novel CD123-directed immunoconjugate SGN-CD123A, consisting of a humanized anti-CD123 antibody conjugated to a highly potent DNA binding pyrrolobenzodiazepine (PBD) dimer drug via a protease-cleavable dipeptide linker. An engineered cysteine on each heavy chain attaching the PBD dimer to the antibody allows uniform drug loading of approximately two PBD dimers per antibody. Fluorescence microscopy studies show that SGN-CD123A is rapidly internalized and traffics to lysosomes within hours of binding to CD123-positive AML cells. Uptake of the antibody-drug-conjugate (ADC) induced DNA damage as measured by dose-and time-dependent increases in the phosphorylation of histone 2AX (γH2AX) and cell death associated with G2-M cell cycle arrest, caspase-3 activity, formation of cleaved poly ADP-ribose polymerase, and DNA fragmentation in target cells.The anti-leukemic activity of SGN-CD123A was assessed in cytotoxicity assays in 12 AML cell lines and 23 primary AML patient samples with variable cytogenetic abnormalities (favorable, intermediate and adverse) and multi-drug resistance (MDR) status. SGN-CD123A was highly active in 11 of 12 AML cell lines tested (mean IC50, 6 ng/ml; range of 0.02 to 38 ng/ml), including 4 of 5 MDR-positive cell lines, whereas it was inactive in CD123-negative HEL92.1.7 AML cells. SGN-CD123A was also active against 20 of 23 primary samples isolated from AML patients (mean IC50 of responsive samples, 0.8 ng/mL; range of 0.06 to 2.5 ng/ml). In both AML panels, molecular abnormalities, including the presence of a p53 mutation, FLT3-ITD, as well as MDR positivity, did not affect the in vitro cytotoxic activity of SGN-CD123A.In vivo antitumor activity was evaluated in AML xenograft models established with CD123-positive, MDR-negative Molm-13, HNT-34, and THP-1 cell lines and the MDR-positive KG-1 cell line. In all of the in vivo models, a single dose of SGN-CD123A delivered significant antitumor activity. SGN-CD123A dosed once at 10 mcg/kg yielded complete cures and significant survival advantage in the Molm-13 disseminated model of AML (p < 0.0001 compared to untreated or control ADC groups). Durable complete regressions were observed with a single dose of 25 or 75 mcg/kg in the MDR-negative HNT-34 subcutaneous model (p =0.0019 to control ADC group). In the THP-1 model, a single 100 mcg/kg dose of SGN-CD123A yielded durable complete regressions in 2 of 8 mice (p=0.0003 to untreated) whereas a higher dose of 300 mcg/kg gave complete tumor regressions in all mice (p < 0.0001 to untreated group). SGN-CD123A was also effective in a MDR-positive model of AML. A single dose of 100 mcg/kg SGN-CD123A significantly decreased tumor growth (p=0.003 to controls) whereas a single dose of 300 mcg/kg yielded durable complete regressions compared to the control groups in the KG-1 subcutaneous model of MDR-positive AML (p =0.008). Early evidence of the antitumor activity of SGN-CD123A was found in tumors harvested from THP-1 mice. Within 48h of dosing with SGN-CD123A, tumor cells showed elevated levels of the DNA damage marker γH2AX and changes in nuclear morphology.These data demonstrate that SGN-CD123A exhibits significant antitumor activity against a broad panel of primary AML samples and in preclinical models of MDR-positive AML that are characteristically resistant to chemotherapy. CD123-directed delivery of PBD may represent a promising new approach for the treatment of AML. DisclosuresSutherland:Seattle Genetics, Inc.: Employment. Yu:Seattle Genetics, Inc: Employment, Equity Ownership. Walter:Seattle Genetics, Inc: Consultancy, Research Funding. Westendorf:Seattle Genetics, Inc: Employment. Valliere-Douglass:Seattle Genetics, Inc: Employment. Pan:Seattle Genetics, Inc: Employment. Sussman:Seattle Genetics, Inc: Employment. Anderson:Seattle Genetics, Inc: Employment. Zeng:Seattle Genetics, Inc: Employment. Stone:Seattle Genetics, Inc: Employment. Klussman:Seattle Genetics, Inc: Employment. Ulrich:Seattle Genetics, Inc: Employment. Jonas:Seattle Genetics, Inc: Employment. Senter:Seattle Genetics, Inc: Employment. Drachman:Seattle Genetics, Inc: Employment. Benjamin:Seattle Genetics, Inc: Employment.

Comparison of characteristics and mortality in multidrug resistant (MDR) and non-MDR tuberculosis patients in China.

BackgroundWe conducted a cohort study to compare the characteristics of MDR-TB with non-MDR-TB patients and to measure long term (9-year) mortality rate and determine factors associated with death in China.MethodsWe reviewed the medical records of 250 TB cases from a 2001 survey to compare 100 MDR-TB patients with 150 non-MDR-TB patients who were treated in 2001-2002. Baseline attributes extracted from the records were compared between the two cohorts and long-term mortality and risk factors were determined at nine-year follow-up in 2010.ResultsAmong the 234 patients successfully followed up, 63 (26.9%) were female and 171 (73.1 %) were male. MDR-TB patients had poorer socioeconomic status compared to non-MDRTB. Nine years after the diagnosis of TB, 69 or 29.5 % of the 234 patients had died (32 or 21.6 % of non-MDR-TB versus 37 or 43.0 % of MDR-TB) and the overall mortality rate was 39/1000 per year (PY) (27/1000 PY among non-MDR versus 63/1000 PY among MDR-TB). Factors associated with death included: MDR status (hazard ratio (HR): 1.86; CI: 1.09-3.13), limited education of primary school or lower (HR: 2.51; CI 1.34-4.70) and received TB treatment during the nine-year period (HR 1.82; 95 % CI 1.02-3.26).ConclusionsMDR-TB was a strong predictor for poor long-term outcome. High quality diagnosis and treatment must be ensured. Greater reimbursement or free treatment may be needed to provide access for the poor and vulnerable populations, and to increase treatment compliance.

Impact of Sepsis Classification and Multidrug-Resistance Status on Outcome Among Patients Treated With Appropriate Therapy.

To assess the impact of sepsis classification and multidrug-resistance status on outcome in patients receiving appropriate initial antibiotic therapy. A retrospective cohort study. Barnes-Jewish Hospital, a 1,250-bed teaching hospital. Individuals with Enterobacteriaceae sepsis, severe sepsis, and septic shock who received appropriate initial antimicrobial therapy between June 2009 and December 2013. Clinical outcomes were compared according to multidrug-resistance status, sepsis classification, demographics, severity of illness, comorbidities, and antimicrobial treatment. We identified 510 patients with Enterobacteriaceae bacteremia and sepsis, severe sepsis, or septic shock. Sixty-seven patients (13.1%) were nonsurvivors. Mortality increased significantly with increasing severity of sepsis (3.5%, 9.9%, and 28.6%, for sepsis, severe sepsis, and septic shock, respectively; p < 0.05). Time to antimicrobial therapy was not significantly associated with outcome. Acute Physiology and Chronic Health Evaluation II was more predictive of mortality than age-adjusted Charlson comorbidity index. Multidrug-resistance status did not result in excess mortality. Length of ICU and hospital stay increased with more severe sepsis. In multivariate logistic regression analysis, African-American race, sepsis severity, Acute Physiology and Chronic Health Evaluation II score, solid-organ cancer, cirrhosis, and transfer from an outside hospital were all predictors of mortality. Our results support sepsis severity, but not multidrug-resistance status as being an important predictor of death when all patients receive appropriate initial antibiotic therapy. Future sepsis trials should attempt to provide appropriate antimicrobial therapy and take sepsis severity into careful account when determining outcomes.

Drug efflux pump expression in 50,000 molecularly-profiled cancer patients.

11108 Background: The multidrug resistance (MDR) phenotype reduces the efficacy of various chemotherapies. MDR is linked to the overexpression of ATP-binding cassette (ABC) transporters in cancer cells, including P-glycoprotein (PGP/ABCB1), multidrug resistance protein (MRP1/ABCC1) and breast cancer resistance protein (BCRP/ABCG2). We assessed protein expression patterns of the drug efflux pumps across all tumor types for insight on how to exploit MDR status to circumvent treatment dilemmas. Methods: 51,939 patients molecularly profiled with a commercial multiplatform approach (Caris Life Sciences) were evaluated. Protein expression by IHC was assessed. The Caris Registry was queried for patients in this analysis with available clinical outcomes. Results: Across all tumors profiled (n = 51,939), MRP1 positivity (pos.) was highest at 81% (19935/24682), BCRP at 66% (8849/13409) and PGP the lowest at 23% (11969/51313). GI cancers exhibited the most abundant expression of all three drug pumps (80%, 90%, 53%), with highest average combined expression observed in liver cancers (81%). In contrast, brain, thymic and head and neck cancers exhibited the lowest average combined expression of all 3 drug pumps (39%, 40% and 42%, respectively). 6,002 patients were evaluable for co-expression with 29% (1728/6002) exhibiting pos. for all 3 drug pumps (ABC+) (highest frequencies in colon, pancreas, ovary, breast and lung), 42% (2494/6002) pos. for 2/3 drug pumps and 21% (1263/6002) pos. for 1/3 drug pumps. Only 9% (517/6002) exhibited negative status for all 3 drug pumps (ABC-) (highest frequencies in breast, lung, ovary, skin and endometrial). To determine the prognostic role of the drug pumps on patient survival, we assessed the differences in median survival between a cohort of ABC+ (n = 31) and ABC – (n = 27) patients with breast (n = 6, 2), ovary (n = 12, 6) and lung cancers (n = 13,19). Median survival since specimen used for profiling was collected for ABC + was 596 days compared to 855 days for ABC – patients. Conclusions: Tumors show broad and overlapped expression patterns for drug efflux pumps. Further study is needed to determine how transporter expression may impact clinical outcomes (e.g. ABC - status is more favorable than ABC + status).

γH2AX is a biomarker of modulated cytostatic drug resistance.

ONE reason for reduced therapeutic efficiency of cancer chemotherapies is the appearance of multidrug resistance. Plasma membrane glycoprotein (P-gp) is recognized as one of the best characterized drug efflux pumps playing a central role in the absorption and disposition of many drugs, including chemotherapeutic agents. Increased P-gp activity has been suggested and reported to be an indicator of chemotherapeutic failure. Therefore, P-gp activity has been used as a potential target in being able to reverse multidrug resistance. Cytostatic drugs such as etoposide in combination with the immunosuppressive cyclosporine A may inhibit P-gp activity, ultimately resulting in intracellular enrichment of the targeted drug (1). One issue in cancer therapy involves the highly varying drug response among patients. To assess the multidrug resistance status for personalized cancer therapy, an assay that can provide results to monitor the cytostatic effect of antineoplastic agents in combination with different drugs is highly desirable. Many of these drugs, like etoposide, cause DNA double strand breaks (DSBs) that may eventuate in clonogenic death. DSBs are one of the most biologically significant DNA damage lesions that leads to chromosome breakage and/or rearrangement, mutagenesis and loss or gain of genetic information (2). The phosphorylation of H2AX histone proteins which are located in the vicinity of the DSBs is known as one of the earliest responses to DNA DSBs in cells. Induction of DNA DSBs in live mammalian cells triggers the phosphorylation of Ser139 in the SQ motif near the C-terminal of H2AX protein, which results in the phosphorylated form of H2AX, termed cH2AX. cH2AX signals appear as discrete nuclear “foci” which can be visualized and quantified by a number of methods including fluorescence microscopy and flow cytometry, following immunostaining procedures with fluorescence-coupled antibodies. The cH2AX foci counting approach has been used in numerous studies to assess the relationship between cH2AX foci removal and the rate of DSBs repair (3). Each DSB is represented by an individual cH2AX focus with a ratio of 1:1 and after successful repair of DSBs, the level of cH2AX foci decline over time in the presence of normal physiological repair mechanisms. The presence of persistent cH2AX indicates impaired DNA repair. Therefore, cH2AX quantification may prove to be a sensitive biomarker of DNA DSBs in human cells and has been suggested for biomonitoring tumor progression and treatment response (4). DSBs are directly generated by exogenous agents such as ionizing radiation and antitumor drugs (bleomycin, mitoxantrone, etoposide). Because mammalian cells respond to DSBs by activating a multitude of proteins involved in signalling and DNA repair pathways, the very nature of DSBs poses such a threat to cell survival that DNA damage checkpoint proteins may be activated to initiate cellular division arrest. This provides time for DNA repair to proceed before mitosis is completed or in the case of overwhelming damage, apoptosis ensues (5). Therefore, detection of accumulated cH2AX foci may be an efficient method for assessing multidrug resistance in cancer therapy as presented by Reddig et al. in this issue of Cytometry A (page XXX).

Transmission, prevention and management of drug resistant tuberculosis

The rise of drug-resistant tuberculosis threatens the very fabric of traditional tuberculosis control efforts, particularly in South Africa, Eastern Europe and parts of Asia. Initial complacency was guided by laboratory observations which suggested that drug-resistant strains of Mycobacterium tuberculosis are less transmissible than drug-susceptible “wild-type” strains. However, the fact that young children in close contact with adult drug-resistant tuberculosis patients frequently became infected and/or diseased, usually with the same strain, provided clear evidence of transmissibility. Advanced genomic analysis has since provided novel insight into the evolution and spread of drug-resistant strains, highlighting unique epidemiological features related to programmatic management in specific geographic areas. Young children and immune compromised individuals are at high risk to develop active tuberculosis following close contact with a drug-resistant source case. Although observational data demonstrate clear benefit from contextualized post-exposure prophylaxis, formal guidance remains limited pending more robust information from large field trials. Wide scale roll-out of the MTB/RIF Xpert® test has facilitated early diagnosis of cases with drug-resistant tuberculosis. Multiple challenges such as high cost, technical and maintenance issues, result interpretation, false positive read-outs and misassignment of multi-drug resistant (MDR) status in cases with rifampicin mono-resistance remain, especially in resource-limited settings. In addition, MDR treatment programs are inadequate and heavily dependent on external donor funding in most settings, this restricts treatment access and threatens the sustainability of programs.

Multi-epitope peptide vaccines for human lymphatic filariasis

The rise of drug-resistant tuberculosis threatens the very fabric of traditional tuberculosis control efforts, particularly in South Africa, Eastern Europe and parts of Asia. Initial complacency was guided by laboratory observations which suggested that drug-resistant strains of Mycobacterium tuberculosis are less transmissible than drug-susceptible “wild-type” strains. However, the fact that young children in close contactwith adult drug-resistant tuberculosis patients frequently became infected and/or diseased, usually with the same strain, provided clear evidence of transmissibility. Advanced genomic analysis has since provided novel insight into the evolution and spread of drugresistant strains, highlighting unique epidemiological features related to programmaticmanagement in specific geographic areas. Young children and immune compromised individuals are at high risk todevelopactive tuberculosis following close contactwith a drug-resistant source case. Although observational data demonstrate clearbenefit fromcontextualizedpost-exposureprophylaxis, formal guidance remains limited pendingmore robust information from large field trials. Wide scale roll-out of the MTB/RIF Xpert® test has facilitated early diagnosis of cases with drug-resistant tuberculosis. Multiple challenges such as high cost, technical and maintenance issues, result interpretation, false positive read-outs and misassignment of multi-drug resistant (MDR) status in cases with rifampicin mono-resistance remain, especially in resource-limited settings. In addition, MDR treatment programs are inadequate and heavily dependent on external donor funding inmost settings, this restricts treatment access and threatens the sustainability of programs.

The impact of multidrug resistance on outcomes in ventilator-associated pneumonia

Multidrug-resistant (MDR) organisms in ventilator-associated pneumonia were found in 49 of 107 patients and were associated with home antibiotics, pre-ventilator-associated pneumonia hospital stay, and health care exposure. Overall, MDR organisms were associated with increased mortality (P = .006). On multivariate analysis, MDR status was modulated by organism class. In nonfermenting gram-negative rods, no association between MDR and mortality was found, but, in all other organisms, MDR was associated with increased mortality risk (hazard ratio, 6.15; 95% confidence interval: 1.80-21.05, P = .004).

Observations on Citrobacter species from a tertiary care health center with special reference to multi-drug resistance and presence of CTX-M gene.

Citrobacter is an important nosocomial pathogen and its multi-drug resistant (MDR) isolates are increasingly being reported across the globe. They are known to produce extended spectrum beta lactamase (ESBL) and harbor CTX-M gene. The aim was to isolate Citrobacter sp. from clinical specimens, analyze their MDR status and look for the presence of CTX-M gene. In this prospective study, Citrobacter isolates positive for ESBL on screening, were confirmed by combined disc method along with minimum inhibitory concentration (MIC) for cefotaxime. In selected cefotaxime resistant isolates, multiplex polymerase chain reaction was done for blaCTX-M gene. Of 146 Citrobacter sp. isolated, most (73%) were from admitted patients and hospital stay of >72 h and prior antibiotic intake were the most common associated factors. Maximum isolates were from pus (41.1%). Citrobacter freundii was the commonest species (49%) followed by Citrobacter koseri (28%); 79 were ESBL producers. Seventy were cefotaxime resistant as shown by MIC. blaCTX-M gene was detected in 15/40 of these isolates, all belonged to CTX-M group 1. Overall incidence of Citrobacter in our setup is low, but they were mostly MDR, and ESBL production was high, which is a cause of concern. blaCTX-M gene detection is important because of its rapid transmission to other bacterial species.

Control of an Outbreak ofAcinetobacter baumanniiin Burn Unit in a Tertiary Care Hospital of North India

Acinetobacterinfection is increasing in hospitals and now it is considered as a global threat, as it can be easily transmitted and remain viable in the hospital environment for a long time due to its multidrug-resistant status, resistance to desiccation, and tendency to adhere to inanimate surfaces. Outbreaks caused by multidrug-resistantAcinetobacter baumannii(MDRAB) are difficult to control and have substantial morbidity and mortality, especially in vulnerable host. Here we are describing an outbreak of multidrug-resistantAcinetobacter baumanniiin burn unit of a tertiary care hospital in India followed by its investigation and infection control measures taken to curtail the outbreak. Outbreak investigation and environmental sampling are the key factors which help in deciding the infection control strategies for control of outbreak. Implementation of contact precautions, hand hygiene, personnel protective equipment, environmental disinfection, isolation of patients, and training of health care workers are effective measures to control the outbreak of MDRAB in burn unit.