Noroviruses as a cause of diarrhea in travelers to Guatemala, India, and Mexico.

Noroviruses (NoVs) are increasingly being recognized as an important enteric pathogen of gastroenteritis worldwide. The prevalence of NoVs as a cause of diarrhea acquired by travelers in developing countries is not well known. We examined the prevalence and importance of NoV infection in three international traveler cohorts with diarrhea acquired in three developing regions of the world, Mexico, Guatemala, and India. We also characterized the demographics and symptoms associated with NoV diarrhea in these travelers. Stool samples from 571 international travelers with diarrhea were evaluated for traditional enteropathogens. NoVs were identified using reverse transcription-PCR and probe hybridization. NoVs were identified in 10.2% of cases of travelers' diarrhea and, overall, was the second most common pathogen, following diarrheagenic Escherichia coli. The detection of NoV diarrhea significantly varied over the three study time periods in Guadalajara, Mexico, ranging from 3 of 98 (3.0%) diarrheal stools to 12 of 100 (12.0%) fecal specimens (P=0.03). The frequency of NoV diarrhea was also dependent upon the geographic region, with 17 of 100 (17.0%) travelers to Guatemala, 23 of 194 (11.9%) travelers to India, and 3 of 79 (3.8%) travelers to Mexico testing positive for NoVs from 2002 to 2003 (P=0.02). NoVs are important pathogens of travelers' diarrhea in multiple regions of the world. Significant variation in the prevalence of NoV diarrhea and in the predominant genogroup infecting travelers was demonstrated, dependent upon the specific geographic location and over time.

Pasteurella multocida vertebral osteomyelitis, myositis and epidural abscess in a diabetic cirrhotic patient.

Pasteurella multocida is frequently associated with soft tissue infections related to animal bites or scratches. These infections are usually mild but can lead to serious complications especially in high-risk patients. We present a chronic Pasteurella. multocida vertebral osteomyelitis with extensive spondylodiscitis, myositis and epidural abscess in a patient with diabetes and liver cirrhosis. Pasteurella multocida should be suspected in bone and soft tissue infections even if the site of infection is distant to the site of the animal bite, scratch or lick, especially in high-risk patients.

Pharmacokinetic evaluation of single-dose intravenous daptomycin in patients with thermal burn injury.

Daptomycin pharmacokinetics were evaluated for burn patients. Burn patients had decreases in the maximum concentration of the drug in serum (44%) and the area under the concentration-time curve (47%) and increases in the volume of distribution (64%) and total clearance (77%) compared to healthy volunteers. In burn patients, daptomycin at 10 to 12 mg/kg of body weight/day would be required to achieve drug exposures similar to those for healthy volunteers receiving 6 mg/kg.

Case report: Mycobacterium bovis orchitis post intravesical Bacillus Calmette Guerin.

Bacillus Calmette-Guérin (BCG) therapy is a common adjunctive therapy for superficial bladder carcinoma but there has been noted to be complications from this treatment ranging from general disseminated infections to osteomuscular involvement. We report a case regarding a 63 year old gentleman who presented with right testicular swelling and pain and later found to have evidence consistent with Mycobacterium bovis orchitis. We also detail a literature review regarding genitourinary infections secondary to BCG therapy and discussion regarding current testing modalities.

Clinical Outcomes in Patients With Gram-Negative Infections Treated With Optimized Dosing Cefepime Over Various Minimum Inhibitory Concentrations.

BACKGROUND: The Clinical and Laboratory Standards Institute (CLSI) revised cefepime interpretive criteria, introducing the susceptible dose-dependent category for Enterobacteriaceae with a minimum inhibitory concentration (MIC) of 4 to 8 µg/mL in 2014. Limited clinical data support these new categories. This study compares outcomes of patients treated with standard and high-dose cefepime across various MICs. METHODS: We retrospectively reviewed cases of pneumonia or bacteremia caused by gram-negative organisms treated with adequate doses of cefepime for ≥48 hours. Outcomes were compared for MICs of ≤2 (low), 4 (medium), and 8 µg/mL (high). The primary end point was clinical failure, the secondary end point was microbiological failure. RESULTS: Ninety cases met the inclusion criteria: 46, 25, and 19 patients with low, medium, or high MIC, respectively. Multivariate logistic regression revealed that the medium (odds ratio [OR]: 9.13, P < .01) and high (OR: 6.79, P = .01) MIC groups had increased clinical failure. CONCLUSION: Cefepime therapy, even at CLSI-recommended doses, had an increased risk of clinical failure for gram-negative pathogens with MICs of 4 or 8 µg/mL. This finding suggests that higher dosing regimens (2 g every 8 hours or 1 g every 6 hours) may be necessary to treat serious gram-negative infections with elevated MICs.

Treatment of travelers' diarrhea: randomized trial comparing rifaximin, rifaximin plus loperamide, and loperamide alone.

BACKGROUND & AIMS: Antimotility agents provide rapid temporary relief of acute diarrhea, whereas antibiotics slowly cure the illness. Thus, the combination of an antimotility agent and an antibiotic may provide greater therapeutic benefit than either drug alone. This study evaluated the efficacy and safety of rifaximin-loperamide in the treatment of travelers' diarrhea. METHODS: Consenting adults with acute diarrhea (> or =3 unformed stools in 24 hours with > or =1 symptom of enteric infection) were randomized to receive rifaximin 200 mg 3 times daily for 3 days; loperamide 4 mg initially followed by 2 mg after each unformed stool; or a combination of both drugs using the same dosing regimen. The primary end point was the median time from beginning therapy until passing the last unformed stool. RESULTS: A total of 310 patients completed treatment with rifaximin (n = 102), loperamide (n = 104), or rifaximin-loperamide combination therapy (n = 104). The groups showed demographic similarity. Rifaximin and rifaximin-loperamide significantly reduced the median time until passage of the last unformed stool (32.5 +/- 4.14 h and 27.3 +/- 4.13 h, respectively) vs loperamide (69 +/- 4.11 h; P = .0019). The mean number of unformed stools passed during illness was lower with rifaximin-loperamide (3.99 +/- 4.28) compared with rifaximin (6.23 +/- 6.90; P = .004) or loperamide alone (6.72 +/- 6.93; P = .002). All treatments were well tolerated with a low incidence of adverse events. CONCLUSIONS: Rifaximin-loperamide therapy provided rapid symptomatic improvement and greater overall wellness compared with either agent alone.

Loperamide plus azithromycin more effectively treats travelers' diarrhea in Mexico than azithromycin alone.

BACKGROUND: Because the combination of loperamide and some antimicrobials has proven to be more efficacious than the antimicrobial agent alone in the treatment of travelers' diarrhea, we set out to prove loperamide plus azithromycin was more efficacious than azithromycin alone. METHODS: During the summers of 2002 to 2003, 176 US adults recently arrived in Guadalajara, Mexico were enrolled in a prospective, double-blinded, randomized trial of the treatment of acute diarrhea. Subjects received single doses (1,000 or 500 mg) of azithromycin or a single 500 mg dose of azithromycin plus loperamide. Subjects gave a pre- and post-treatment stool sample for analysis and maintained daily diaries of symptoms and passage of stools. RESULTS: The duration of diarrhea was significantly (p=0.0002) shorter following treatment with azithromycin plus loperamide (11 h) than with either dose of azithromycin alone (34 h). In the first 24 hours, the average number of unformed stools passed was 3.4 (azithromycin alone) and 1.2 (combination) for a significant (p<0.0001) difference of 2.2 unformed stools. This difference equated with 20% of azithromycin-treated subjects continuing to pass six or more unformed stools in the first 24 hours post-treatment compared with only 1.7% of combination-treated subjects. CONCLUSIONS: For the treatment of travelers' diarrhea in an Escherichia coli predominant region of the world, a single 500 mg dose of azithromycin appeared as effective as a 1,000 mg dose. Loperamide plus 500 mg of azithromycin was safe and more effective than either dose of azithromycin. To realize the substantial clinical benefit that accrues to a subset of subjects, we feel loperamide should routinely be used in combination with an antimicrobial agent to treat travelers' diarrhea.

Rifaximin treatment of pathogen-negative travelers' diarrhea.

BACKGROUND: Antibacterial drugs appear to be effective in shortening the illness of a majority of cases of travelers' diarrhea. METHODS: This was a subanalysis from two randomized, double-blind, placebo-controlled trials in adult travelers with acute diarrhea treated with rifaximin 200 mg three times a day or placebo for 3 days. Efficacy was assessed by the interval beginning with the first dose of medication and ending with the last unformed stool passed after becoming well [time to last unformed stool (TLUS)]; number of unformed stools passed; percent with clinical improvement; and incidence of wellness achieved. RESULTS: Stool pathogens were not identified in pretreatment samples in 122 of 322 (38%) patients and 106 of 230 (46%) randomized to rifaximin and placebo, respectively. Among pathogen-negative patients, rifaximin was more effective than placebo for median TLUS (33 vs 68 h, p < 0.005), mean number of unformed stools passed (6.5 vs 8.6, p < 0.0001), and clinical wellness (77% vs 61%, p = 0.01). The adverse-event profiles between rifaximin and placebo were similar. CONCLUSIONS: More than one third of patients with travelers' diarrhea had pathogen-negative illness. Rifaximin was effective in treating the illness without associated side effects. These results are consistent with the hypothesis that undetected bacterial pathogens are the most likely cause of travelers' diarrhea without definable cause.

Guidelines for the prevention and treatment of travelers' diarrhea: a graded expert panel report.

BACKGROUND: : Travelers' diarrhea causes significant morbidity including some sequelae, lost travel time and opportunity cost to both travelers and countries receiving travelers. Effective prevention and treatment are needed to reduce these negative impacts. METHODS: : This critical appraisal of the literature and expert consensus guideline development effort asked several key questions related to antibiotic and non-antibiotic prophylaxis and treatment, utility of available diagnostics, impact of multi-drug resistant (MDR) colonization associated with travel and travelers' diarrhea, and how our understanding of the gastrointestinal microbiome should influence current practice and future research. Studies related to these key clinical areas were assessed for relevance and quality. Based on this critical appraisal, guidelines were developed and voted on using current standards for clinical guideline development methodology. RESULTS: : New definitions for severity of travelers' diarrhea were developed. A total of 20 graded recommendations on the topics of prophylaxis, diagnosis, therapy and follow-up were developed. In addition, three non-graded consensus-based statements were adopted. CONCLUSIONS: : Prevention and treatment of travelers' diarrhea requires action at the provider, traveler and research community levels. Strong evidence supports the effectiveness of antimicrobial therapy in most cases of moderate to severe travelers' diarrhea, while either increasing intake of fluids only or loperamide or bismuth subsalicylate may suffice for most cases of mild diarrhea. Further studies are needed to address knowledge gaps regarding optimal therapies, the individual, community and global health risks of MDR acquisition, manipulation of the microbiome in prevention and treatment and the utility of laboratory testing in returning travelers with persistent diarrhea.

A randomized, double-blind, multicenter study of rifaximin compared with placebo and with ciprofloxacin in the treatment of travelers' diarrhea.

Rifaximin was compared with placebo and ciprofloxacin for treatment of travelers' diarrhea in a randomized, double-blind clinical trial. Adult travelers (N = 399) consulting travel clinics in Mexico, Guatemala, and India were randomized to receive rifaximin 200 mg three times a day, ciprofloxacin (500 mg two times a day and placebo once a day), or placebo three times a day for 3 days. Patients recorded in daily diaries the time and consistency of each stool and documented symptoms for 5 days after treatment. Stool samples were collected for microbiologic evaluations before and after treatment. The median time to last unformed stool (TLUS) in the rifaximin group (32.0 hours) was less than one half that in the placebo group (65.5 hours; P = 0.001; risk ratio 1.6; 95% confidence interval 1.2, 2.2; primary efficacy endpoint). The median TLUS in the ciprofloxacin group was 28.8 hours (P = 0.0003 versus placebo; P = 0.35 versus rifaximin). Rifaximin was less effective than ciprofloxacin for invasive intestinal bacterial pathogens. Oral rifaximin is a safe and effective treatment of travelers' diarrhea caused by noninvasive pathogens.

Safety and tolerability of the antibacterial rifaximin in the treatment of travellers' diarrhoea.

Although travellers' diarrhoea can sometimes be associated with postinfectious complications, the condition is typically self-limiting. The infectious-diarrhoea guidelines subcommittees of the Infectious Disease Society of America and the American College of Gastroenterology recommend empirical antibacterial therapy for travellers' diarrhoea. Because therapy is directed largely at relieving symptoms and minimising inconvenience, the chosen antibacterial should ideally be both efficacious and pose a low risk of adverse effects. This review discusses the safety and tolerability of rifaximin in the treatment of travellers' diarrhoea, with a focus on data from controlled clinical trials. Data were obtained from a MEDLINE search using the key word 'rifaximin' with no date limits and from the rifaximin New Drug Application submitted to the US FDA for approval to market rifaximin in the US.Currently, the antibacterials considered as standard treatment for travellers' diarrhoea are systemically absorbed, carry defined risks of adverse effects, and have many uses other than the treatment of enteric disease. The minimally absorbed (<0.4%) oral antibacterial rifaximin constitutes a non-systemic approach to antidiarrhoeal therapy that should overcome some of the limitations of current antibacterials used for travellers' diarrhoea. Rifaximin is differentiated from these, and most other antibacterials, by having a tolerability profile comparable with that of placebo and minimal potential for drug interactions. To date, clinically relevant resistance to rifaximin has not been observed. As the first nonabsorbable antibacterial to be marketed for travellers' diarrhoea, rifaximin should help to change the management paradigm for travellers' diarrhoea and other gastrointestinal illnesses from a systemic approach to a predictably safer, non-systemic approach.

A randomized, double-blind, placebo-controlled trial of rifaximin to prevent travelers' diarrhea.

BACKGROUND: Travelers' diarrhea causes substantial morbidity and postinfectious irritable bowel syndrome. OBJECTIVE: To evaluate nonabsorbable rifaximin for prevention of travelers' diarrhea. DESIGN: Randomized, double-blind, placebo-controlled clinical trial. SETTING: Guadalajara, Mexico. PARTICIPANTS: U.S. students. INTERVENTION: On arrival in Guadalajara, Mexico, 210 U.S. adults received rifaximin (200 mg/d, 200 mg twice daily, or 200 mg 3 times daily) or placebo for 2 weeks. MEASUREMENTS: Participants were followed daily for 3 weeks for enteric disease and symptoms and daily for 5 weeks for drug side effects. Changes in intestinal coliform flora were studied. RESULTS: Travelers' diarrhea developed in 14.74% of participants taking rifaximin and 53.70% of those taking placebo (rate ratio, 0.27 [95% CI, 0.17 to 0.43]). Rifaximin provided 72% and 77% protection against travelers' diarrhea and antibiotic-treated travelers' diarrhea, respectively (P < 0.001 for both), and all rifaximin doses were superior to placebo. In the groups that did not report travelers' diarrhea, rifaximin significantly reduced the occurrence of mild diarrhea (P = 0.02) and moderate and severe intestinal problems (P = 0.009 for pain or cramps; P = 0.02 for excessive gas). Rates of adverse events were comparable in the rifaximin and placebo groups. Minimal changes in coliform flora were found during rifaximin therapy. LIMITATIONS: Rifaximin safely prevented travelers' diarrhea in Mexico, where most cases are caused by diarrhea-producing Escherichia coli. A study is needed in Asia to determine whether rifaximin can prevent diarrhea caused by invasive bacterial pathogens. CONCLUSIONS: Rifaximin prevents travelers' diarrhea with minimal changes in fecal flora, and more liberal chemoprophylaxis against this disease should be considered. Future studies should evaluate whether rifaximin is effective in preventing postinfectious irritable bowel syndrome.

Nonantimicrobial agents in the prevention and treatment of traveler's diarrhea.

Among the nonantimicrobial agents that are available and useful for the prevention of traveler's diarrhea are bismuth subsalicylate-containing preparations, which can provide a rate of protection of up to 65% when taken 4 times daily. In one study, the probiotic Lactobacillus GG was found to provide 49% protection against traveler's diarrhea, but results with this agent and other probiotics have been highly variable and geographically inconsistent. Tannin albuminate plus ethacridine lactate provided 36% protection, but it is not widely available. Among the nonantimicrobial agents that are available and useful for the treatment of traveler's diarrhea are bismuth subsalicylate-containing preparations, which reduce the passage of loose stools by 16%-18%. The antisecretory and antimotility agent loperamide reduces the passage of loose stools by approximately 50% and has been especially useful, in combination with antimicrobial agents, in reducing the total duration of posttreatment diarrhea to a matter of hours.

Antibacterial chemoprophylaxis in the prevention of traveler's diarrhea: evaluation of poorly absorbed oral rifaximin.

The use of antibacterial drugs was first shown to effectively reduce the occurrence of traveler's diarrhea nearly 50 years ago. The approach was not encouraged for general use by a Consensus Development Conference in 1985 because of concerns about adverse effects of the drugs and the possible development of resistance against systemically absorbed drugs. When therapy with poorly absorbed rifaximin was shown to be as effective as therapy with systemically absorbed drugs in shortening the duration of traveler's diarrhea, without the development of resistant coliform flora, the use of rifaximin for the prevention of traveler's diarrhea was studied. In the present study, rifaximin provided 72% protection against the development of diarrhea and 77% protection against active or treated diarrhea during 2 weeks of drug administration to United States students in Mexico. Rifaximin offers a potentially useful approach for preventing traveler's diarrhea. Potential areas of future study include use of the drug to prevent diarrhea due to mucosally invasive bacteria, including ciprofloxacin-resistant Campylobacter species, and to reduce the occurrence of postinfectious irritable bowel syndrome.

Fatal amphotericin B overdose due to administration of nonlipid formulation instead of lipid formulation.

The toxicity of amphotericin B deoxycholate has led to increased preference for lipid formulations with more favorable safety profiles. However, the primary use of lipid formulations is cost prohibitive, and many hospital formularies list both lipid and nonlipid formulations. A dispensing and administration error that caused amphotericin B deoxycholate to be given instead of liposomal amphotericin B related in a fatality. Measures to prevent confusion and aid in understanding the differences between lipid and nonlipid formulations of amphotericin B should be implemented.

Enteric pathogens in Mexican sauces of popular restaurants in Guadalajara, Mexico, and Houston, Texas.

BACKGROUND: The transmission of traveler's diarrhea is primarily foodborne. OBJECTIVE: To examine the level of microbial contamination of tabletop sauces found in Mexican-style restaurants. DESIGN: Cross-sectional study of Mexican sauces. SETTING: Mexican restaurants in Guadalajara, Mexico, and Houston, Texas, during the summer of 1998. MEASUREMENTS: 71 sauces from Guadalajara and 25 sauces from Houston were examined. The number of sauces contaminated with Escherichia coli, the median number of E. coli colonies per gram of sauce, and enteropathogens were identified. RESULTS: 47 of 71 sauces from Guadalajara were contaminated with E. coli versus 10 of 25 sauces from Houston (P = 0.03); the median number of E. coli colonies per gram of sauce was 1000 in the Guadalajara sauces versus 0.0 in the Houston sauces (P = 0.007). Among sauces from Guadalajara tested for diarrheogenic E. coli, 4 of 43 sauces contained enterotoxigenic E. coli and 14 of 32 contained enteroaggregative E. coli. CONCLUSIONS: Contamination with E. coli was common in samples of Mexican tabletop sauces from Guadalajara restaurants. These sauces commonly contained enteric pathogens.

Cefepime free minimum concentration to minimum inhibitory concentration (fCmin/MIC) ratio predicts clinical failure in patients with Gram-negative bacterial pneumonia.

Cefepime is an antibiotic commonly used in nosocomial infections. The objective of this study was to elucidate the relationship between cefepime exposure and clinical outcome in patients with Gram-negative bacterial pneumonia. A previously published population pharmacokinetic model of cefepime was validated in 12 adult patients with normal renal function by measuring plasma concentrations at steady-state. Additionally, clinical outcomes for 33 patients with Gram-negative bacterial pneumonia who received cefepime monotherapy were determined. The free minimum concentration (fCmin) to MIC ratio for each patient was determined by conditioning the validated pharmacokinetic model using patient-specific creatinine clearance (CLCr), dosing regimen and cefepime MIC of the organism isolated, and was subsequently correlated with clinical failure. Classification and regression tree (CART) analysis was used to determine the most significant drug exposure breakpoint. Mean±S.D. CLCr and cefepime Cmin in the 12 patients were 87.5±21.2mL/min and 6.2±3.8mg/L, respectively. In comparison, the Cmin predicted by the pharmacokinetic model was 5.8mg/L using a CLCr of 90mL/min. MICs of organisms ranged from 0.5mg/L to 8mg/L. Percent time free drug above MIC of 100% was achieved in 32/33 patients, but 12 patients experienced clinical failure. CART analysis determined patients with an fCmin/MIC≥2.1 had a significantly lower risk of clinical failure (OR=0.11, 95% CI 0.02-0.67; P=0.017). The fCmin/MIC ratio is a useful predictor of clinical failure in Gram-negative bacterial pneumonia. The clinical utility of fCmin/MIC in therapeutic drug monitoring should be further explored.