Isolation and concentration of bacteria from blood using microfluidic membraneless dialysis and dielectrophoresis.

A microfluidic system that combines membraneless microfluidic dialysis and dielectrophoresis to achieve label-free isolation and concentration of bacteria from whole blood is presented. Target bacteria and undesired blood cells are discriminated on the basis of their differential susceptibility to permeabilizing agents that alter the dielectrophoretic behavior of blood cells but not bacteria. The combined membraneless microdialysis and dielectrophoresis system isolated 79 ± 3% of Escherichia coli and 78 ± 2% of Staphylococcus aureus spiked into whole blood at a processing rate of 0.6 mL h-1. Collection efficiency was independent of the number of target bacteria up to 105 cells. Quantitative PCR analysis revealed that bacterial 16S rDNA levels were enriched more than 307-fold over human DNA in the fraction recovered from the isolation system compared with the original specimen. These data demonstrate feasibility for an instrument to accelerate the detection and analysis of bacteria in blood by first isolating and concentrating them in a microchamber.

Efficacy and safety of antiretrovirals in HIV-infected patients with cancer.

At 30 years into the HIV infection epidemic, the optimal antiretroviral (ARV) regimen for infected patients with cancer remains unknown. We therefore sought to retrospectively study different ARV regimens used in this population. Data from HIV-infected patients seen at The University of Texas MD Anderson Cancer Center in Houston, Texas, USA, from 2001 to 2012 were reviewed. Patients received nucleoside reverse transcriptase inhibitors (NRTIs) plus protease inhibitors (PIs), non-NRTIs (NNRTIs), integrase strand-transfer inhibitors (INSTIs), or combinations of these. A total of 154 patients were studied. Most patients were male (80%), white (51%) and had haematological malignancies (HMs) (58%). NRTIs were combined with PIs (37%), NNRTIs (32%), INSTIs (19%) or combinations of these (11%). INSTIs were the most commonly used in patients with HM and in those receiving high-dose steroids or topoisomerase inhibitors (p <0.05). Side-effects occurred in 35%, 14%, 3% and 6% of patients receiving PIs, NNRTIs, INSTIs and combinations, respectively (p 0.001). Grade 3-4 adverse events were uncommon. Multivariate logistic regression analysis demonstrated that INSTIs and NNRTIs were nine times (95% confidence interval (CI), 1.4-50.8) and 11 times (95% CI, 1.9-64.7) more likely to be effective at 6 months, respectively, than PIs. This is the largest reported analysis studying different ARV regimens in HIV-infected cancer patients. Combinations that included PIs were the least favourable. NNRTIs and INSTIs had comparable efficacy, but INSTIs appeared to be the better tolerated ARVs in patients with HM or those receiving various chemotherapeutic agents.

Severe parainfluenza virus type 2 supraglottitis in an immunocompetent adult host: an unusual cause of a paramyxoviridae viral infection.

Parainfluenza virus is a major cause of respiratory illness in humans, manifesting from mild upper respiratory tract infection to bronchiolitis and pneumonia, especially in children. We report - to our knowledge - the first case of a nonimmunocompromised adult patient with human parainfluenza type 2 supraglottitis immediately after returning from China.

Rifaximin versus ciprofloxacin for the treatment of traveler's diarrhea: a randomized, double-blind clinical trial.

Rifaximin is a poorly absorbed rifamycin derivative under investigation for treatment of infectious diarrhea. Adult students from the United States in Mexico and international tourists in Jamaica were randomized to receive either rifaximin (400 mg twice per day) or ciprofloxacin (500 mg twice per day) for 3 days, following a double-blinded model, from June 1997 to September 1998. A total of 187 subjects with diarrhea were studied. Time from initiation of therapy to passage of last unformed stool was comparable for those receiving rifaximin or ciprofloxacin (median, 25.7 hours versus 25.0 hours, respectively). There was no significant difference in the proportion of subjects in the 2 groups with respect to clinical improvement during the first 24 hours (P=.199), failure to respond to treatment (P=.411), or microbiological cure (P=.222). The incidence of adverse events was low and similar in each group. Rifaximin is a safe and effective alternative to ciprofloxacin in the treatment of traveler's diarrhea.

Enteroaggregative Escherichia coli as a major etiologic agent in traveler's diarrhea in 3 regions of the world.

Enteroaggregative Escherichia coli (EAEC) has been reported to cause traveler's diarrhea and persistent diarrhea in children in developing countries and in immunocompromised patients. To clarify the prevalence of EAEC in traveler's diarrhea, we studied 636 US, Canadian, or European travelers with diarrhea: 218 in Guadalajara, Mexico (June--August 1997 and 1998), 125 in Ocho Rios, Jamaica (September 1997--May 1998), and 293 in Goa, India (January 1997--April 1997 and October 1997--February 1998). Stool samples were tested for conventional enteropathogens. EAEC strains were identified by use of the HEp-2 assay. EAEC was isolated in 26% of cases of traveler's diarrhea (ranging from 19% in Goa to 33% in Guadalajara) and was second only to enterotoxigenic E. coli as the most common enteropathogen in all areas. Identification of EAEC reduced the number of cases for which the pathogen was unknown from 327 (51%) to 237 (37%) and explained 28% of cases with unknown etiology. EAEC was a major cause of traveler's diarrhea in 3 geographically distinct study areas.

In vitro antimicrobial susceptibility testing of bacterial enteropathogens causing traveler's diarrhea in four geographic regions.

The emergence of resistant enteropathogens has been reported worldwide. Few data are available on the contemporary in vitro activities of commonly used antimicrobial agents against enteropathogens causing traveler's diarrhea (TD). The susceptibility patterns of antimicrobial agents currently available or under evaluation against pathogens causing TD in four different areas of the world were evaluated. Pathogens were identified in stool samples from U.S., Canadian, or European adults (18 years of age or older) with TD during 1997, visiting India, Mexico, Jamaica, or Kenya. MICs of 11different antimicrobials were determined against 284 bacterial enteropathogens by the agar dilution method. Ciprofloxacin, levofloxacin, ceftriaxone, and azithromycin were highly active in vitro against the enteropathogens, while traditional antimicrobials such as ampicillin, trimethoprim, and trimethoprim/sulfamethoxazole showed high levels and high frequencies of resistance. Rifaximin, a promising and poorly absorbable drug, had an MIC at which 90% of the strains tested were inhibited of 32 microg/ml, 250 times lower than the concentration of this drug in the stools. Amdinocillin, nalidixic acid, and doxycycline showed moderate activity. Fluoroquinolones are still the drugs of choice for TD in most regions of the world, although our study has a limitation due to the lack of Escherichia coli samples from Kenya and possible bias in selection of the patients for evaluation. Azithromycin and rifaximin should be considered as promising new agents. The widespread in vitro resistance of the traditional antimicrobial agents reported since the 1980s and the new finding of resistance to fluoroquinolones in Southeast Asia are the main reasons for monitoring carefully the antimicrobial susceptibility patterns worldwide and for developing and evaluating new antimicrobial agents for the treatment of TD.

Empirical antimicrobial therapy for traveler's diarrhea.

Over 7 million cases of traveler's diarrhea, defined as the passage of > or = 3 unformed stools in a 24-h period, occur each year among visitors to developing countries. Bacterial enteric pathogens are the most common etiologic agents isolated. Preliminary clinical results for patients with diarrhea predominantly caused by Campylobacter species have shown that azithromycin may be an effective alternative to fluoroquinolones for the treatment of traveler's diarrhea.

Intestinal secretory immunoglobulin A response to enteroaggregative Escherichia coli in travelers with diarrhea.

We examined stool samples from travelers for secretory immunoglobulin A (sIgA) to enteroaggregative Escherichia coli (EAEC) during episodes of acute diarrhea. Ten paired samples from 10 patients with diarrhea caused by EAEC were examined for the presence of specific sIgA by dot blot and Western blot immunoassays. Five samples were positive by dot blotting, and two samples were positive by Western blotting.

Reactive arthritis associated with typhoid vaccination in travelers: report of two cases with negative HLA-B27.

As international travel to developing countries increases, more people seek medical advice concerning food and water-borne diseases, including typhoid fever. Prevention of typhoid fever in high-risk groups (travelers to endemic areas, laboratory workers and household contacts of typhoid carriers) should rely primarily on prevention of exposure. However, immunization is an important adjunct. The decision to immunize against typhoid fever should be individualized, taking into account the benefits versus the risk of possible adverse reactions. Cases of reactive arthritis have been associated with the heat-phenol inactivated 'whole cell' parenteral vaccine, but to our knowledge reactive arthritis has not been previously reported with the oral form (Ty21a). This is a report of HLA-B27 negative reactive arthritis occurring in two travelers after the administration of oral Ty21a typhoid vaccine.

Improved detection of enterotoxigenic Escherichia coli among patients with travelers' diarrhea, by use of the polymerase chain reaction technique.

This study sought to determine whether a specific polymerase chain reaction (PCR) for enterotoxigenic Escherichia coli (ETEC) toxins after chaotropic extraction of DNA from stool would increase the detection of ETEC over that of conventional oligonucleotide probe hybridization of 5 E. coli colonies per stool sample (a standard method). By DNA hybridization, 29 (21%) of 140 patients were positive for ETEC, and 59 (42%) of 140 were positive for ETEC when PCR was used. Sensitivity of the PCR assay was confirmed through spiked stool experiments to be approximately 100-1000 ETEC colonies per sample. Specificity of the assay was determined by showing an absence of ETEC by the PCR technique in a subgroup of 48 subjects and by confirming the presence of ETEC DNA of positive samples by dot blot procedure. PCR technique detected significantly more ETEC infections in these subjects than did the hybridization method (P<.0001).

Enteroaggregative Escherichia coli as a cause of traveler's diarrhea: clinical response to ciprofloxacin.

The purpose of this study was to determine the role of enteroaggregative Escherichia coli (EAEC) in the development of traveler's diarrhea and the clinical response of patients with EAEC diarrhea following treatment with ciprofloxacin. Sixty-four travelers with diarrhea and no other recognized enteropathogen were enrolled in treatment studies in Jamaica and Mexico from July 1997 to July 1998. EAEC was isolated from 29 travelers (45.3%). There was a significant reduction in the duration of posttreatment diarrhea in the 16 patients treated with ciprofloxacin, as compared with that in the 13 patients who received placebo (mean of 35.3 versus 55.5 hours; P = .049). There was a nonsignificant reduction in the mean number of unformed stools passed during the 72 hours after enrollment in the ciprofloxacin-treated group (5.6), as compared with that in the placebo group (7.5) (P = .128). This study provides additional evidence that EAEC should be considered as a cause of antibiotic-responsive traveler's diarrhea.

Bacterial gut infections.

Infections of the bowel as a result of bacterial enteropathogens are one of the most common medical problems. The use of novel molecular biology techniques and the recent development of new antimicrobial drugs and vaccines are helping us to identify, understand, treat and prevent these infections.

Human granulocytic ehrlichiosis in a renal transplant patient: case report and review of the literature.

BACKGROUND: Human ehrlichiosis, a newly described zoonotic infection, can be classified as human monocytic ehrlichiosis (HME) or human granulocytic ehrlichiosis (HGE). Although the clinical manifestations of HME and HGE are similar, the type of leukocyte infected, the etiologic agent, and the tick vector are distinct. METHODS: We report the first case of HGE in a solid organ transplant recipient and review the literature on HGE. RESULTS: Our patient displayed typical epidemiological, clinical, and laboratory features and responded promptly to therapy with doxycycline. CONCLUSIONS: Although opportunistic infections are relatively common in the posttransplant population, one must always consider other infections that occur in normal hosts as well. Human ehrlichiosis should be included in the differential diagnosis for transplant patients with fever, cytopenias, and hepatitis, especially if exposure to ticks in endemic areas has occurred.