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North Liberty, Iowa, United States

Farrell D.J.,JMI Laboratories
Journal of Clinical Gastroenterology | Year: 2013

Irritable bowel syndrome (IBS), a chronic, nonfatal illness is commonly encountered in clinical practice; however, treatment options are limited and often ineffectual. Despite this, there is increasing evidence that bacterial overgrowth in the bowel (dysbiosis) may be an etiological factor in IBS. This has lead to studies in which the antibiotic agent rifaximin has been used to reduce the microbial burden in the bowel, to some extent alleviating the symptoms of IBS. Rifaximin is a member of the rifamycin class of antibiotics, which when administered orally has the distinctions of being gut specific coupled with poor systemic absorption, characteristics that are suggested to limit the development of bacterial resistance. The rifamycins are currently used to treat serious human diseases including tuberculosis, meningococcal disease, methicillin-resistant Staphylococcus aureus and Clostridium difficile infections. The use of rifamycins in the treatment of these diseases is associated with the development of antibiotic resistance over time. When considering the importance of the rifamycins in the treatment of serious human diseases, the large number of patients affected by IBS, and the lack of scientific evidence available on the development of antibiotic resistance to rifaximin over the long-term when used in the gut, it is advisable that the use of rifaximin as a therapy for IBS should be limited to single, acute, short-term treatment. Copyright © 2013 by Lippincott Williams & Wilkins.

Gales A.C.,Federal University of Sao Paulo | Jones R.N.,JMI Laboratories | Sader H.S.,Federal University of Sao Paulo | Sader H.S.,JMI Laboratories
Journal of Antimicrobial Chemotherapy | Year: 2011

Objectives: To comparatively evaluate the antimicrobial activities of colistin and polymyxin B with those of other antimicrobials against a worldwide collection of 40625 Gram-negative bacilli. Methods: Antimicrobial susceptibility testing was performed and interpreted using the CLSI broth microdilution method except for colistin against Enterobacteriaceae. Results: The polymyxins showed potent in vitro activities (MIC 90, ≤0.5-1 mg/L) against this large collection of clinical isolates, with very low resistance rates (<0.1%-1.5%). Resistance to the polymyxins remained stable among organisms tested except for Klebsiella spp. isolates collected from the Asia-Pacific and Latin American regions, where a trend towards greater resistance was observed (P≤0.05). In addition, an important reduction in imipenem susceptibility among Acinetobacter spp. and Klebsiella spp. was demonstrated in most geographical regions. Conclusions: Although the polymyxins showed excellent in vitro activity against the vast majority of Gramnegative bacilli evaluated, a trend to greater resistance was observed in the Asia-Pacific and Latin American regions. Therefore, the clinical use of polymyxins must be cautious and surveillance monitored. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

Jones R.N.,JMI Laboratories | Stilwell M.G.,JMI Laboratories
Diagnostic Microbiology and Infectious Disease | Year: 2013

Dalbavancin is an investigational lipoglycopeptide having an extended serum elimination half-life allowing once-weekly dosing. Data from testing 1357 strains of uncommonly isolated species expand the dalbavancin spectrum details as follows (MIC50/90): β-haemolytic streptococcal serogroups C, F, and G (≤0.03/≤0.03 μg/mL), 7 viridans group of streptococci (≤0.03/≤0.03-0.06 μg/mL), 5 Corynebacterium spp. (0.06/0.12 μg/mL), Listeria monocytogenes (0.06/0.12 μg/mL), and Micrococcus spp. (≤0.03/≤0.03 μg/mL). Among all reported isolates, 99.8% of tested strains were inhibited at dalbavancin MIC values at ≤0.12 μg/mL. Dalbavancin remains very potent against rarer Gram-positive pathogens, using in vitro test experience with organisms cultured through 2011. © 2013 Elsevier Inc.

Sader H.S.,JMI Laboratories | Flamm R.K.,JMI Laboratories | Jones R.N.,JMI Laboratories | Jones R.N.,Tufts University
Antimicrobial Agents and Chemotherapy | Year: 2013

Ceftaroline-avibactam and comparator agents were tested by the broth microdilution method against 20,089 isolates consecutively collected in 2010 and 2011 from 75 U.S. medical centers. Ceftaroline-avibactam was active against Enterobacteriaceae (4,908 strains; MIC90, 0.25 μg/ml; highest MIC, 4 μg/ml), including meropenem-nonsusceptible Klebsiella spp. and ceftazidimenonsusceptible Enterobacter cloacae strains (MIC90, 1 μg/ml for both). Ceftaroline-avibactam was also active against ceftriaxone-nonsusceptible Streptococcus pneumoniae (MIC90, 0.25 μg/ml) and methicillin-resistant Staphylococcus aureus (MIC90, 1 μg/ml). Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Castanheira M.,JMI Laboratories | Farrell S.E.,JMI Laboratories | Krause K.M.,Cerexa Inc. | Jones R.N.,JMI Laboratories | Sader H.S.,JMI Laboratories
Antimicrobial Agents and Chemotherapy | Year: 2014

Escherichia coli (328 isolates), Klebsiella pneumoniae (296), Klebsiella oxytoca (44), and Proteus mirabilis (33) isolates collected during 2012 from the nine U.S. census regions and displaying extended-spectrum-β-lactamase (ESBL) phenotypes were evaluated for the presence of β-lactamase genes, and antimicrobial susceptibility profiles were analyzed. The highest ESBL rates were noted for K. pneumoniae (16.0%, versus 4.8 to 11.9% for the other species) and in the Mid-Atlantic and West South Central census regions. CTX-M group 1 (including CTX-M-15) was detected in 303 strains and was widespread throughout the United States but was more prevalent in the West South Central, Mid-Atlantic, and East North Central regions. KPC producers (118 strains [112 K. pneumoniae strains]) were detected in all regions and were most frequent in the Mid-Atlantic region (58 strains). Thirteen KPC producers also carried blaCTX-M. SHV genes encoding ESBL activity were detected among 176 isolates. Other β-lactamase genes observed were CTX-M group 9 (72 isolates), FOX (10), TEM ESBL (9), DHA (7), CTX-M group 2 (3), NDM-1 (2 [Colorado]), and CTX-M groups 8 and 25 (1). Additionally, 62.9% of isolates carried>2 β-lactamase genes. KPC producers were highly resistant to multiple agents, but ceftazidime-avibactam (MIC50/90, 0.5/2 μg/ml) and tigecycline (MIC50/90, 0.5/1 μg/ ml) were the most active agents tested. Overall, meropenem (MIC50,<0.06 μg/ml), ceftazidime-avibactam (MIC50, 0.12 to 0.5 μg/ml), and tigecycline (MIC50, 0.12 to 2 μg/ml) were the most active antimicrobials when tested against this collection. NDM-1 producers were resistant to all β-lactams tested. The diversity and increasing prevalence of β-lactamase-producing Enterobacteriaceae have been documented, and ceftazidime-avibactam was very active against the vast majority of β-lactamase-producing strains isolated from U.S. hospitals. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

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