Clinical experience in 52 patients with tigecycline-containing regimens for salvage treatment of Mycobacterium abscessus and Mycobacterium chelonae infections.

OBJECTIVES: We report the largest clinical experience using tigecycline-containing regimens for salvage treatment of patients with Mycobacterium abscessus and Mycobacterium chelonae. PATIENTS AND METHODS: Data were collected from 52 patients on emergency/compassionate use (n = 38) or two open-label studies (n = 7 patients each). Based on information that was available, 46 (88.5%) of the subjects received antibiotic therapy prior to treatment with tigecycline. Treatment groups were evaluated based on length of tigecycline therapy (<1 and ≥1 month). ClinicalTrials.gov identifiers: Study 205, NCT00600600 and Study 310, NCT00205816. RESULTS: The most commonly used concomitant antimicrobials were macrolides, amikacin and linezolid. Pulmonary disease was the most common presentation (36/52; 69.2%), and 58.3% of these patients had underlying cystic fibrosis. The majority were M. abscessus complex (n = 30) or M. chelonae/abscessus (n = 4). With therapy ≥1 month (mean, 255.0 ±â€Š265.7 days), 10/15 patients (66.7%) with cystic fibrosis and 16/26 (61.5%) overall were considered improved. Skin/soft-tissue/bone infections were the most common extrapulmonary infections. With therapy ≥1 month (mean, 143 ±â€Š123 days), 9/12 patients (75.0%) were considered improved. Nine of the 16 cases reported as failures regardless of site of infection occurred in patients who stopped treatment due to adverse events. There were eight deaths; none was related to tigecycline. CONCLUSIONS: Tigecycline given for ≥1 month as part of a multidrug regimen resulted in improvement in >60% of patients with M. abscessus and M. chelonae infections, including those with underlying cystic fibrosis, despite failure of prior antibiotic therapy. Adverse events were reported in >90% of cases, the most common being nausea and vomiting.

Honeybees and tetracycline resistance.

Like animals and people, insects can serve as both collectors and disseminators of antibiotic resistance genes, as exquisitely demonstrated by a recent study (B. Tian, N. H. Fadhil, J. E. Powell, W. K. Kwong, and N. A. Moran, mBio 3[6]:e00377-12, doi:10.1128/mBio.00377-12, 2012). Notably, the relatively confined ecosystem of the honeybee gut demonstrates a large propensity for harboring a diverse set of tetracycline resistance genes that reveal the environmental burden resulting from the long-time selective pressures of tetracycline use in the honeybee industry. As in humans and animals, these genes have become established in the native, nonpathogenic flora of the insect gut, adding credence to the concept that commensal floras provide large reservoirs of resistance genes that can readily move into pathogenic species. The homology of these tetracycline resistance determinants with those found in tetracycline-resistant bacteria associated with animals and humans strongly suggests a dissemination of similar or identical genes through shared ecosystems. The emergence of linked coresistances (ampicillin and tetracycline) following single-antibiotic therapy mirrors reports from other studies, namely, that long-term, single-agent therapy will result in resistance to multiple drugs. These results contrast with the marked absence of diverse, single- and multiple-drug resistance genes in wild and domestic bees that are not subjected to such selective pressures. Prospective studies that simultaneously track both resistance genes and antibiotic residues will go far in resolving some of the nagging questions that cloud our understanding of antibiotic resistance dissemination.

The frequency of antibiotic-resistant bacteria in homes differing in their use of surface antibacterial agents.

Antibacterial agents are common in household cleaning and personal care products, but their long-range impacts on commensal and pathogenic household bacteria are largely unknown. In a one-time survey of 38 households from Boston, MA [19] and Cincinnati, OH [18], 13 kitchen and bathroom sites were sampled for total aerobic bacteria and screened for gram phenotype and susceptibility to six antibiotic drug families. The overall bacterial titers of both user (2 or more antibacterial cleaning or personal care products) and non-user (0 or 1 product) rooms were similar with sponges and sink drains consistently showing the highest overall titers and relatively high titers of antibiotic-resistant bacteria. The mean frequency of resistant bacteria ranged from ≤20 % to as high as 45 % and multi-drug resistance was common. However, no significant differences were noted between biocide users and non-users. The frequency of pathogen recovery was similar in both user and non-user groups.

Topical ophthalmic moxifloxacin elicits minimal or no selection of fluoroquinolone resistance among bacteria isolated from the skin, nose, and throat.

PURPOSE: To investigate whether moxifloxacin therapy of bacterial conjunctivitis in children changes the moxifloxacin susceptibility of bacterial isolates in eyes, cheeks below eyes, nares, and throat. METHODS: Patients (age: 1 to 12 years, n = 105) with bacterial conjunctivitis were treated topically with moxifloxacin three times a day for 7 days. Gender- and age-matched subjects with normal eyes (age: 1 to 12 years, n = 57) served as the control group. Microbiological specimens were collected on days 1 (prior to therapy), 8 (1 day after end of therapy), and 42 (follow-up). Specimens were processed to recover total bacteria and bacteria that grew on fluoroquinolone-selective media. Bacteria were identified to the species level and susceptibility to moxifloxacin and selected other antibiotics determined. RESULTS: The primary pathogens recovered from the infected eyes on day 1 before therapy were Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. None of the pre-therapy isolates of H. influenzae and S. pneumoniae were resistant to moxifloxacin. Isolates of these two pathogenic species were also recovered primarily from the nose and eyes. Moxifloxacin-resistant S. aureus isolates (minimum inhibitory concentration 1.0 µg/mL or greater) were recovered from the nose and throat prior to topical dosing on day 1. However, there was no change in the frequency of moxifloxacin-resistant isolates of S. aureus following treatment with moxifloxacin. CONCLUSION: Treatment of conjunctivitis with topical ophthalmic moxifloxacin did not select for moxifloxacin resistance in H. influenzae, S. pneumoniae, or S. aureus in the eye or distal body sites.

Food animals and antimicrobials: impacts on human health.

Antimicrobials are valuable therapeutics whose efficacy is seriously compromised by the emergence and spread of antimicrobial resistance. The provision of antibiotics to food animals encompasses a wide variety of nontherapeutic purposes that include growth promotion. The concern over resistance emergence and spread to people by nontherapeutic use of antimicrobials has led to conflicted practices and opinions. Considerable evidence supported the removal of nontherapeutic antimicrobials (NTAs) in Europe, based on the "precautionary principle." Still, concrete scientific evidence of the favorable versus unfavorable consequences of NTAs is not clear to all stakeholders. Substantial data show elevated antibiotic resistance in bacteria associated with animals fed NTAs and their food products. This resistance spreads to other animals and humans-directly by contact and indirectly via the food chain, water, air, and manured and sludge-fertilized soils. Modern genetic techniques are making advances in deciphering the ecological impact of NTAs, but modeling efforts are thwarted by deficits in key knowledge of microbial and antibiotic loads at each stage of the transmission chain. Still, the substantial and expanding volume of evidence reporting animal-to-human spread of resistant bacteria, including that arising from use of NTAs, supports eliminating NTA use in order to reduce the growing environmental load of resistance genes.

Microbial contamination of musical wind instruments.

Retrospective and prospective studies were used to assess the numbers, types and persistence of microbes that contaminate wind instruments. All previously played instruments (n = 20) harbored viable bacteria as well as mold and/or yeast. Reedinstruments consistently carried higher microbial loads than did flutes or trumpets. Instruments played within the previous three days bore typical mouth flora, while bacteria recovered after 72 h following play consisted of normal environmental flora. Prospective studies tested survival of potentially pathogenic bacteria (Staphylococcus, Streptococcus, Moraxella, Escherichia coli and attenuated Mycobacterium tuberculosis) when applied to reeds or following simulated 'play' of a clarinet. All species survived for a maximum of 24-48 h on reeds, except Mycobacterium, which persisted through 13 days. In simulated play experiments, test bacteria could persist for up to five days. These findings support the establishment of guidelines for decontamination of wind instruments and for sharing or transfer of these instruments among players.

A sensitive human bone assay for quantitation of tigecycline using LC/MS/MS.

Tigecycline (Tygacil,Wyeth) is a first-in-class, broad spectrum antibiotic with activity against multiple-resistant organisms. In order to address the unexpectedly low tigecycline concentrations in human bone samples analyzed using a LC/MS/MS method developed elsewhere, we have developed and validated a new and sensitive human bone assay for the quantitation of tigecycline using LC/MS/MS. The new method utilizes the addition of a stabilizing agent to the human bone sample, homogenization of human bone in a strong acidic-methanol extraction solvent, centrifugation of the bone suspension, separation by liquid chromatography, and detection of tigecycline by mass spectrometry. Linearity was demonstrated over the concentration range from 50 to 20,000 ng/g using a 0.1g human bone sample. The intra- and inter-day accuracy of the assay was within 100+/-15%, and the corresponding precision (CV) was <15%. The stability of tigecycline was evaluated and shown to be acceptable under the assay conditions. The extraction recovery of tigecycline with the current method was 79% when using radio-labeled rat bone samples as a substitute for human bone samples. Twenty-four human bone samples collected previously from volunteers without infections who had elective orthopedic surgery after receiving a single dose of tigecycline were re-analyzed using the current validated method. Tigecycline concentrations in these samples ranged from 238 to 794 ng/g with a mean value 9 times higher than the mean concentration previously reported. The data demonstrated that the current method has significantly higher extraction efficiency than the previously reported method.

A phase I and pharmacokinetic study of temsirolimus (CCI-779) administered intravenously daily for 5 days every 2 weeks to patients with advanced cancer.

PURPOSE: Patients with advanced cancer received temsirolimus (Torisel, CCI-779), a novel inhibitor of mammalian target of rapamycin, i.v. once daily for 5 days every 2 weeks to determine the maximum tolerated dose, toxicity profile, pharmacokinetics, and preliminary antitumor efficacy. EXPERIMENTAL DESIGN: Doses were escalated in successive cohorts of patients using a conventional phase I clinical trial design. Samples of whole blood and plasma were collected to determine the pharmacokinetics of temsirolimus and sirolimus, its principal metabolite. RESULTS: Sixty-three patients were treated with temsirolimus (0.75-24 mg/m(2)/d). The most common drug-related toxicities were asthenia, mucositis, nausea, and cutaneous toxicity. The maximum tolerated dose was 15 mg/m(2)/d for patients with extensive prior treatment because, in the 19 mg/m(2)/d cohort, two patients had dose-limiting toxicities (one with grade 3 vomiting, diarrhea, and asthenia and one with elevated transaminases) and three patients required dose reductions. For minimally pretreated patients, in the 24 mg/m(2)/d cohort, one patient developed a dose-limiting toxicity of grade 3 stomatitis and two patients required dose reductions, establishing 19 mg/m(2)/d as the maximum acceptable dose. Immunologic studies did not show any consistent trend toward immunosuppression. Temsirolimus exposure increased with dose in a less than proportional manner. Terminal half-life was 13 to 25 hours. Sirolimus-to-temsirolimus exposure ratios were 0.6 to 1.8. A patient with non-small cell lung cancer achieved a confirmed partial response, which lasted for 12.7 months. Three patients had unconfirmed partial responses; two patients had stable disease for >/=24 weeks. CONCLUSION: Temsirolimus was generally well tolerated on this intermittent schedule. Encouraging preliminary antitumor activity was observed.

Antibacterial cleaning products and drug resistance.

We examined whether household use of antibacterial cleaning and hygiene products is an emerging risk factor for carriage of antimicrobial drug-resistant bacteria on hands of household members. Households (N = 224) were randomized to use of antibacterial or nonantibacterial cleaning and hygiene products for 1 year. Logistic regression was used to assess the influence of antibacterial product use in homes. Antibacterial product use did not lead to a significant increase in antimicrobial drug resistance after 1 year (odds ratio 1.33, 95% confidence interval 0.74-2.41), nor did it have an effect on bacterial susceptibility to triclosan. However, more extensive and longer term use of triclosan might provide a suitable environment for emergence of resistant species. Further research on this issue is needed.

Transcriptional profiles in peripheral blood mononuclear cells prognostic of clinical outcomes in patients with advanced renal cell carcinoma.

PURPOSE: Given their accessibility, surrogate tissues, such as peripheral blood mononuclear cells (PBMC), may provide potential predictive biomarkers in clinical pharmacogenomic studies. In leukemias and lymphomas, the prognostic value of peripheral blast expression profiles is clear; however, it is unclear whether circulating mononuclear cells of patients with solid tumors might yield profiles with similar prognostic associations. EXPERIMENTAL DESIGN: In this study, we evaluated the association of expression profiles in PBMCs with clinical outcomes in patients with advanced renal cell cancer. Transcriptional patterns in PBMCs of 45 renal cell cancer patients were compared with clinical outcome data at the conclusion of a phase II study of the mTOR kinase inhibitor CCI-779 to determine whether pretreatment transcriptional patterns in PBMCs were correlated with eventual patient outcomes. RESULTS: Unsupervised hierarchical clustering of the PBMC profiles using all expressed genes identified clusters of patients with significant differences in survival. Cox proportional hazards modeling showed that the expression levels of many PBMC transcripts were predictors for the patient outcomes of time to progression and overall survival (time to death). Supervised class prediction approaches identified multivariate expression patterns in PBMCs capable of assigning favorable outcomes of time to death and time to progression in a test set of renal cancer patients, with overall performance accuracies of 72% and 85%, respectively. CONCLUSIONS: The present study provides the first example of gene expression profiling in peripheral blood, a clinically accessible surrogate tissue, for identifying patterns of gene expression associated with higher likelihoods of positive outcome in patients with a solid tumor.

Antibacterial resistance worldwide: causes, challenges and responses.

The optimism of the early period of antimicrobial discovery has been tempered by the emergence of bacterial strains with resistance to these therapeutics. Today, clinically important bacteria are characterized not only by single drug resistance but also by multiple antibiotic resistance--the legacy of past decades of antimicrobial use and misuse. Drug resistance presents an ever-increasing global public health threat that involves all major microbial pathogens and antimicrobial drugs.

Relationship between triclosan and susceptibilities of bacteria isolated from hands in the community.

The possible association between triclosan and bacterial susceptibility to antibiotic was examined among staphylococci and several species of gram-negative bacteria (GNB) isolated from the hands of individuals in a community setting. Hand cultures from individuals randomized to using either antibacterial cleaning and hygiene products (including a hand soap containing 0.2% triclosan) or nonantibacterial cleaning and hygiene products for a 1-year period were taken at baseline and at the end of the year. Although there was no statistically significant association between triclosan MICs and susceptibility to antibiotic, there was an increasing trend in the association the odds ratios (ORs) for all species were compared at baseline (OR = 0.65, 95% confidence interval [95%CI] = 0.33 to 1.27) versus at the end of the year (OR = 1.08, 95%CI = 0.62 to 1.97) and for GNB alone at baseline(OR = 0.66, 95%CI = 0.29 to 1.51) versus the end of year (OR = 2.69, 95%CI = 0.78 to 9.23) regardless of the hand-washing product used. Moreover, triclosan MICs were higher in some of the species compared to earlier reports on household, clinical, and industrial isolates, and some of these isolates had triclosan MICs in the range of concentrations used in consumer products. The absence of a statistically significant association between elevated triclosan MICs and reduced antibiotic susceptibility may indicate that such a correlation does not exist or that it is relatively small among the isolates that were studied. Still, a relationship may emerge after longer-term or higher-dose exposure of bacteria to triclosan in the community setting.

Randomized phase II study of multiple dose levels of CCI-779, a novel mammalian target of rapamycin kinase inhibitor, in patients with advanced refractory renal cell carcinoma.

PURPOSE: To evaluate the efficacy, safety, and pharmacokinetics of multiple doses of CCI-779, a novel mammalian target of rapamycin kinase inhibitor, in patients with advanced refractory renal cell carcinoma (RCC). PATIENTS AND METHODS: Patients (n = 111) were randomly assigned to receive 25, 75, or 250 mg CCI-779 weekly as a 30-minute intravenous infusion. Patients were evaluated for tumor response, time to tumor progression, survival, and adverse events. Blood samples were collected to determine CCI-779 pharmacokinetics. RESULTS: CCI-779 produced an objective response rate of 7% (one complete response and seven partial responses) and minor responses in 26% of these advanced RCC patients. Median time to tumor progression was 5.8 months and median survival was 15.0 months. The most frequently occurring CCI-779-related adverse events of all grades were maculopapular rash (76%), mucositis (70%), asthenia (50%), and nausea (43%). The most frequently occurring grade 3 or 4 adverse events were hyperglycemia (17%), hypophosphatemia (13%), anemia (9%), and hypertriglyceridemia (6%). Neither toxicity nor efficacy was significantly influenced by CCI-779 dose level. Patients were retrospectively classified into good-, intermediate-, or poor-risk groups on the basis of criteria used by Motzer et al for a first-line metastatic RCC population treated with interferon alfa. Within each risk group, the median survivals of patients at each dose level were similar. CONCLUSION: In patients with advanced RCC, CCI-779 showed antitumor activity and encouraging survival and was generally well tolerated over the three dose levels tested.

Disease-associated expression profiles in peripheral blood mononuclear cells from patients with advanced renal cell carcinoma.

Expression profiling has demonstrated that transcriptomes of primary malignancies differ from those in normal tissue. It is unknown, however, whether there exist "surrogate" transcriptional markers in peripheral blood mononuclear cells (PBMCs) of patients with solid tumors. We identified transcripts expressed differentially between PBMCs from renal cell carcinoma patients and normal subjects, some of which appear to reflect specific immune responses of circulating cells. We also identified small sets of predictor genes distinguishing PBMCs from renal cell carcinoma patients and normal volunteers with high accuracy. The present findings have important implications for diagnosis and future clinical pharmacogenomic studies of antitumor therapies.