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Cai Y, Chai D, Wang R, Liang B, Bai N. Colistin resistance of Acinetobacter baumannii: clinical reports, mechanisms and antimicrobial strategies. J Antimicrob Chemother 2012; 67:1607-15. [PMID: 22441575 DOI: 10.1093/jac/dks084] [Citation(s) in RCA: 388] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Colistin is the last resort for treatment of multidrug-resistant Acinetobacter baumannii. Unfortunately, resistance to colistin has been reported all over the world. The highest resistance rate was reported in Asia, followed by Europe. The heteroresistance rate of A. baumannii to colistin is generally higher than the resistance rate. The mechanism of resistance might be loss of lipopolysaccharide or/and the PmrAB two-component system. Pharmacokinetic/pharmacodynamic studies revealed that colistin monotherapy is unable to prevent resistance, and combination therapy might be the best antimicrobial strategy against colistin-resistant A. baumannii. Colistin/rifampicin and colistin/carbapenem are the most studied combinations that showed promising results in vitro, in vivo and in the clinic. New peptides showing good activity against colistin-resistant A. baumannii are also being investigated.
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Affiliation(s)
- Yun Cai
- Department of Clinical Pharmacology, PLA General Hospital, Beijing 100853, People's Republic of China
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Luo G, Spellberg B, Gebremariam T, Bolaris M, Lee H, Fu Y, French SW, Ibrahim AS. Diabetic murine models for Acinetobacter baumannii infection. J Antimicrob Chemother 2012; 67:1439-45. [PMID: 22389456 DOI: 10.1093/jac/dks050] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Extremely drug-resistant (XDR; i.e. resistant to all antibiotics except colistin or tigecycline) Acinetobacter baumannii has emerged as one of the most common and highly antibiotic-resistant causes of infection. Diabetes is a risk factor for acquisition of and worse outcomes from A. baumannii infection. We sought to develop diabetic mouse models of A. baumannii bacteraemia and pneumonia and validate these models by comparing the efficacy of antibiotic treatment in these models with the established neutropenic mouse models. METHODS Diabetic or neutropenic mice were infected via intravenous inoculation or inhalation in an aerosol chamber with an XDR A. baumannii. Treatment with colistin started 24 h after infection and continued daily for 7 days. Survival served as the primary endpoint while tissue bacterial burden and histopathological examination served as secondary endpoints. RESULTS Lethal infection was achieved for the neutropenic and diabetic mice when infected intravenously or via inhalation. Neutropenic mice were more susceptible to infection than diabetic mice in the pneumonia model and equally susceptible in the bacteraemia model. Both models of bacteraemia were sensitive enough to detect virulence differences among different clinical strains of A. baumannii. In the pneumonia model, colistin treatment was effective in improving survival, reducing lung bacterial burden and histologically resolving the infection compared with placebo only in diabetic mice. CONCLUSIONS We developed novel models of A. baumannii bacteraemia and pneumonia in diabetic mice. These models can be used to study mechanisms of infection, develop immunotherapeutic strategies and evaluate drug efficacies against highly lethal A. baumannii infections.
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Affiliation(s)
- Guanpingsheng Luo
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
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Antoniu SA, Cojocaru I. Inhaled colistin for lower respiratory tract infections. Expert Opin Drug Deliv 2012; 9:333-42. [DOI: 10.1517/17425247.2012.660480] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Betts JW, Kelly SM, Haswell SJ. Antibacterial effects of theaflavin and synergy with epicatechin against clinical isolates of Acinetobacter baumannii and Stenotrophomonas maltophilia. Int J Antimicrob Agents 2011; 38:421-5. [PMID: 21885260 DOI: 10.1016/j.ijantimicag.2011.07.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 07/07/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022]
Abstract
Stenotrophomonas maltophilia and Acinetobacter baumannii are recognised as important nosocomial pathogens; however, due to their intrinsic resistance to multiple antibiotics, treatment options are limited. Polyphenols from black tea have been shown to possess antibacterial action. In this study, the antibacterial effects of various concentrations of theaflavin as well as combinations of theaflavin and epicatechin were determined using the disk diffusion assay. The results showed strong antibacterial activity of theaflavin against eight clinical isolates of S. maltophilia and A. baumannii. Significant synergy (P≤0.05) was also observed between theaflavin and epicatechin against all isolates. Although the mechanisms for this activity and synergy are not well understood, the clinical potential is clear and further research is recommended to determine the modes of action.
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Affiliation(s)
- J W Betts
- Department of Chemistry, University of Hull, Hull HU6 7RX, UK
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Abstract
Emergence and spread of Acinetobacter species, resistant to most of the available antimicrobial agents, is an area of great concern. It is now being frequently associated with healthcare associated infections. Literature was searched at PUBMED, Google Scholar, and Cochrane Library, using the terms ‘Acinetobacter Resistance, multidrug resistant (MDR), Antimicrobial Therapy, Outbreak, Colistin, Tigecycline, AmpC enzymes, and carbapenemases in various combinations. The terms such as MDR, Extensively Drug Resistant (XDR), and Pan Drug Resistant (PDR) have been used in published literature with varied definitions, leading to confusion in the correlation of data from various studies. In this review various mechanisms of resistance in the Acinetobacter species have been discussed. The review also probes upon the current therapeutic options, including combination therapies available to treat infections due to resistant Acinetobacter species in adults as well as children. There is an urgent need to enforce infection control measures and antimicrobial stewardship programs to prevent the further spread of these resistant Acinetobacter species and to delay the emergence of increased resistance in the bacteria.
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Affiliation(s)
- Vikas Manchanda
- Clinical Microbiology and Infectious Diseases Division, Chacha Nehru Bal Chikitsalaya and associated Maulana Azad Medical College, Government of NCT of Delhi, Geeta Colony, Delhi - 110031, India
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Innate immune responses to systemic Acinetobacter baumannii infection in mice: neutrophils, but not interleukin-17, mediate host resistance. Infect Immun 2011; 79:3317-27. [PMID: 21576323 DOI: 10.1128/iai.00069-11] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen with a high prevalence of multiple-drug-resistant strains, causing pneumonia and sepsis. The current studies further develop a systemic mouse model of this infection and characterize selected innate immune responses to the organism. Five clinical isolates, with various degrees of antibiotic resistance, were assessed for virulence in two mouse strains, and between male and female mice, using intraperitoneal infection. A nearly 1,000-fold difference in virulence was found between bacterial strains, but no significant differences between sexes or mouse strains were observed. It was found that microbes disseminated rapidly from the peritoneal cavity to the lung and spleen, where they replicated. A persistent septic state was observed. The infection progressed rapidly, with mortality between 36 and 48 h. Depletion of neutrophils with antibody to Ly-6G decreased mean time to death and increased mortality. Interleukin-17 (IL-17) promotes the response of neutrophils by inducing production of the chemokine keratinocyte-derived chemoattractant (KC/CXCL1), the mouse homolog of human IL-8. Acinetobacter infection resulted in biphasic increases in both IL-17 and KC/CXCL1. Depletion of neither IL-17 nor KC/CXCL1, using specific antibodies, resulted in a difference in bacterial burdens in organs of infected mice at 10 h postinfection. Comparison of bacterial burdens between IL-17a(-/-) and wild-type mice confirmed that the absence of this cytokine did not sensitize mice to Acinetobacter infection. These studies definitely demonstrate the importance of neutrophils in resistance to systemic Acinetobacter infection. However, neither IL-17 nor KC/CXCL1 alone is required for effective host defense to systemic infection with this organism.
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Lim TP, Tan TY, Lee W, Sasikala S, Tan TT, Hsu LY, Kwa AL. In-vitro activity of polymyxin B, rifampicin, tigecycline alone and in combination against carbapenem-resistant Acinetobacter baumannii in Singapore. PLoS One 2011; 6:e18485. [PMID: 21533030 PMCID: PMC3080872 DOI: 10.1371/journal.pone.0018485] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 03/08/2011] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Carbapenem-resistant Acinetobacter baumannii (CR-AB) is an emerging cause of nosocomial infections worldwide. Combination therapy may be the only viable option until new antibiotics become available. The objective of this study is to identify potential antimicrobial combinations against CR-AB isolated from our local hospitals. METHODS AB isolates from all public hospitals in Singapore were systematically collected between 2006 and 2007. MICs were determined according to CLSI guidelines. All CR-AB isolates were genotyped using a PCR-based method. Clonal relationship was elucidated. Time-kill studies (TKS) were conducted with polymyxin B, rifampicin and tigecycline alone and in combination using clinically relevant (achievable) unbound concentrations. RESULTS 31 CR AB isolates were identified. They are multidrug-resistant, but are susceptible to polymyxin B. From clonal typing, 8 clonal groups were identified and 11 isolates exhibited clonal diversity. In single TKS, polymyxin B, rifampicin and tigecycline alone did not exhibit bactericidal activity at 24 hours. In combination TKS, polymyxin plus rifampicin, polymyxin B plus tigecycline and tigecycline plus rifampicin exhibited bactericidal killing in 13/31, 9/31 and 7/31 isolates respectively at 24 hours. Within a clonal group, there may be no consensus with the types of antibiotics combinations that could still kill effectively. CONCLUSION Monotherapy with polymyxin B may not be adequate against polymyxin B susceptible AB isolates. These findings demonstrate that in-vitro synergy of antibiotic combinations in CR AB may be strain dependant. It may guide us in choosing a pre-emptive therapy for CR AB infections and warrants further investigations.
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Affiliation(s)
- Tze-Peng Lim
- Department of Pharmacy, Singapore General Hospital, Singapore, Singapore
- Division of Infectious Diseases, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Thean-Yen Tan
- Department of Microbiology, Changi General Hospital, Singapore, Singapore
| | - Winnie Lee
- Department of Pharmacy, Singapore General Hospital, Singapore, Singapore
| | - S. Sasikala
- Department of Microbiology, Changi General Hospital, Singapore, Singapore
| | | | - Li-Yang Hsu
- Division of Infectious Diseases, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Andrea L. Kwa
- Department of Pharmacy, Singapore General Hospital, Singapore, Singapore
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Wiskirchen DE, Koomanachai P, Nicasio AM, Nicolau DP, Kuti JL. In vitro pharmacodynamics of simulated pulmonary exposures of tigecycline alone and in combination against Klebsiella pneumoniae isolates producing a KPC carbapenemase. Antimicrob Agents Chemother 2011; 55:1420-7. [PMID: 21282442 PMCID: PMC3067181 DOI: 10.1128/aac.01253-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 12/08/2010] [Accepted: 01/22/2011] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant Klebsiella pneumoniae strains that produce a serine carbapenemase (KPC) are emerging worldwide, with few therapeutic options that retain consistent susceptibility. The objective of this study was to determine the effect of combination therapy with tigecycline versus tigecycline alone against KPC-producing isolates (KPC isolates). An in vitro pharmacodynamic model was used to simulate adult steady-state epithelial lining fluid concentrations of tigecycline (50 mg every 12 h) given alone and in combination with either meropenem (2 g by 3-hour infusion every 8 h) or rifampin (600 mg every 12 h). Five KPC isolates with various phenotypic profiles were exposed over 48 h. Time-kill curves were constructed, and the areas under the bacterial killing and regrowth curves (AUBCs) were calculated. No regimens tested were able to maintain bactericidal reductions in CFU over 48 h. The AUBCs for tigecycline and meropenem monotherapies at 48 h ranged from 375.37 to 388.11 and from 348.62 to 383.83 (CFU-h/ml), respectively. The combination of tigecycline plus meropenem significantly reduced the AUBCs at 24 and 48 h for isolates with tigecycline MICs of ≤ 2 μg/ml and meropenem MICs of ≤ 16 μg/ml (P < 0.001) but added no additional activity when the meropenem MIC was 64 μg/ml (P = 0.5). Rifampin provided no additional reduction in CFU or AUBC over tigecycline alone (P = 0.837). The combination of tigecycline with high-dose, prolonged-infusion meropenem warrants further study as a potential treatment option for these multidrug-resistant organisms.
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Affiliation(s)
- Dora E. Wiskirchen
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, Department of Medicine, Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
| | - Pornpan Koomanachai
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, Department of Medicine, Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
| | - Anthony M. Nicasio
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, Department of Medicine, Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
| | - David P. Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, Department of Medicine, Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
| | - Joseph L. Kuti
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, Department of Medicine, Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
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Pachón-Ibáñez ME, Docobo-Pérez F, Jiménez-Mejias ME, Ibáñez-Martínez J, García-Curiel A, Pichardo C, Pachón J. Efficacy of rifampin, in monotherapy and in combinations, in an experimental murine pneumonia model caused by panresistant Acinetobacter baumannii strains. Eur J Clin Microbiol Infect Dis 2011; 30:895-901. [PMID: 21336548 DOI: 10.1007/s10096-011-1173-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 01/11/2011] [Indexed: 11/24/2022]
Abstract
The objective of this work was to evaluate the efficacy of rifampin, and its combinations with imipenem or sulbactam, in an experimental pneumonia model caused by two panresistant Acinetobacter baumannii strains (HUVR99 and HUVR113). Minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) (μg/ml) of the strains were rifampin 128/>128 for both strains, imipenem 128/>256 and 256/>256 for HUVR99 and HUVR113, respectively, and sulbactam >256/>256 for both strains. In time-kill studies, at MICs, rifampin was bactericidal for both strains and sulbactam against the HUVR99 strain. Rifampin plus imipenem or sulbactam, at the MIC or mice C (max), were synergistic. In vivo, against HUVR99 and HUVR113, rifampin (73% and 40%) and its combinations improved the survival with respect to the control group (20% and 0%, p < 0.05), respectively. Rifampin (87% and 46%) and its combinations improved the sterilization of blood cultures with respect to the control groups (0%, p < 0.05). In regard to the bacterial clearance from lungs, rifampin (2.57 ± 2.47 and 5.35 ± 3.03 log(10) cfu/g) and its combinations with imipenem or sulbactam diminished the bacterial lung concentration with respect to the control group (10.89 ± 3.00 and 11.86 ± 0.49, p < 0.05) with both strains. In conclusion, rifampin alone or associated to imipenem or sulbactam were effective for the treatment of murine pneumonia caused by selected panresistant A. baumannii strains.
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Affiliation(s)
- M E Pachón-Ibáñez
- Infectious Diseases Services, Institute of Biomedicine of Sevilla (IBIS), University Hospital Virgen del Rocío/CSIC/University of Sevilla, Sevilla, Spain.
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Carmeli Y, Akova M, Cornaglia G, Daikos GL, Garau J, Harbarth S, Rossolini GM, Souli M, Giamarellou H. Controlling the spread of carbapenemase-producing Gram-negatives: therapeutic approach and infection control. Clin Microbiol Infect 2010; 16:102-11. [PMID: 20085604 DOI: 10.1111/j.1469-0691.2009.03115.x] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Although the rapid spread of carbapenemase-producing Gram-negatives (CPGNs) is providing the scientific community with a great deal of information about the molecular epidemiology of these enzymes and their genetic background, data on how to treat multidrug-resistant or extended drug-resistant carbapenemase-producing Enterobacteriaceae and how to contain their spread are still surprisingly limited, in spite of the rapidly increasing prevalence of these organisms and of their isolation from patients suffering from life-threatening infections. Limited clinical experience and several in vitro synergy studies seem to support the view that antibiotic combinations should be preferred to monotherapies. But, in light of the data available to date, it is currently impossible to quantify the real advantage of drug combinations in the treatment of these infections. Comprehensive clinical studies of the main therapeutic options, broken down by pathogen, enzyme and clinical syndrome, are definitely lacking and, as carbapenemases keep spreading, are urgently needed. This spread is unveiling the substantial unpreparedness of European public health structures to face this worrisome emergency, although experiences from different countries-chiefly Greece and Israel-have shown that CPGN transmission and cross-infection can cause a substantial threat to the healthcare system. This unpreparedness also affects the treatment of individual patients and infection control policies, with dramatic scarcities of both therapeutic options and infection control measures. Although correct implementation of such measures is presumably cumbersome and expensive, the huge clinical and public health problems related to CPGN transmission, alongside the current scarcity of therapeutic options, seem to fully justify this choice.
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Affiliation(s)
- Y Carmeli
- Division of Epidemiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
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Molina J, Cordero E, Pachón J. New information about the polymyxin/colistin class of antibiotics. Expert Opin Pharmacother 2010; 10:2811-28. [PMID: 19929704 DOI: 10.1517/14656560903334185] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Infections by multidrug resistant Gram-negative bacilli (MDR-GNB) have become a major threat for patients hospitalized in intensive care units, representing a prevalent cause of morbimortality in the critically ill, since these microorganisms have developed resistance to most available antimicrobial agents. In this respect, very few therapeutic innovations have been developed in recent years, and it is not foreseen that any new drugs will be commercialized in the near future. Tigecycline represents an effective alternative in this setting, but lacks activity against Pseudomonas aeruginosa, and its use has not been validated for all organ-specific infections. Frequently, only old antibiotics like colistin remain a valid option. New pharmaceutical formulations and dosage regimens of polymyxins have considerably reduced the toxicity previously attributed to these antimicrobials, and have made it possible to reintroduce them into clinical practice. Nonetheless, the effectiveness of polymyxins is still suboptimal, and the expansion of heteroresistance and pan-drug-resistant strains of gram-negative bacilli is of concern. Improvements in dosing, alternative methods of administration and different synergic antimicrobial combinations have been proposed in recent literature, among other measures, to enhance the effectiveness of polymyxins. The latest data regarding polymyxins and their clinical use are discussed in this review.
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Affiliation(s)
- José Molina
- University Hospital Virgen del Rocío, Institute of Biomedicine of Sevilla, Infectious Diseases Service, Av. Manuel Siurot s/n, 41013, Sevilla, Spain
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Efficacy of rifampin and its combinations with imipenem, sulbactam, and colistin in experimental models of infection caused by imipenem-resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2010; 54:1165-72. [PMID: 20047914 DOI: 10.1128/aac.00367-09] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There are currently no defined optimal therapies available for multidrug-resistant (MDR) Acinetobacter baumannii infections. We evaluated the efficacy of rifampin, imipenem, sulbactam, colistin, and their combinations against MDR A. baumannii in experimental pneumonia and meningitis models. The bactericidal in vitro activities of rifampin, imipenem, sulbactam, colistin, and their combinations were tested using time-kill curves. Murine pneumonia and rabbit meningitis models were evaluated using the A. baummnnii strain Ab1327 (with MICs for rifampin, imipenem, sulbactam, and colistin of 4, 32, 32, and 0.5 mg/liter, respectively). Mice were treated with the four antimicrobials and their combinations. For the meningitis model, the efficacies of colistin, rifampin and its combinations with imipenem, sulbactam, or colistin, and of imipenem plus sulbactam were assayed. In the pneumonia model, compared to the control group, (i) rifampin alone, (ii) rifampin along with imipenem, sulbactam, or colistin, (iii) colistin, or (iv) imipenem plus sulbactam significantly reduced lung bacterial concentrations (10.6 +/- 0.27 [controls] versus 3.05 +/- 1.91, 2.07 +/- 1.82, 2.41 +/- 1.37, 3.4 +/- 3.07, 6.82 +/- 3.4, and 4.22 +/- 2.72 log(10) CFU/g, respectively [means +/- standard deviations]), increased sterile blood cultures (0% versus 78.6%, 100%, 93.3%, 93.8%, 73.3%, and 50%), and improved survival (0% versus 71.4%, 60%, 46.7%, 43.8%, 40%, and 85.7%). In the meningitis model rifampin alone or rifampin plus colistin reduced cerebrospinal fluid bacterial counts (-2.6 and -4.4 log(10) CFU/ml). Rifampin in monotherapy or with imipenem, sulbactam, or colistin showed efficacy against MDR A. baumannii in experimental models of pneumonia and meningitis. Imipenem or sulbactam may be appropriate for combined treatment when using rifampin.
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Lim TP, Tan TY, Lee W, Sasikala S, Tan TT, Hsu LY, Kwa AL. In vitro activity of various combinations of antimicrobials against carbapenem-resistant Acinetobacter species in Singapore. J Antibiot (Tokyo) 2009; 62:675-9. [DOI: 10.1038/ja.2009.99] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Drapeau CMJ, Grilli E, Petrosillo N. Rifampicin combined regimens for gram-negative infections: data from the literature. Int J Antimicrob Agents 2009; 35:39-44. [PMID: 19815392 DOI: 10.1016/j.ijantimicag.2009.08.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Accepted: 08/10/2009] [Indexed: 11/27/2022]
Abstract
Multidrug-resistant (MDR) gram-negative bacterial infections are associated with high morbidity and mortality. Given the lack of availability of new highly effective antimicrobial drugs against multiresistant strains, combination regimens are administered that include rifampicin for its demonstrated in vitro synergism with multiple drugs. A literature review was performed of clinical studies reporting the use of rifampicin in the treatment of MDR gram-negative bacterial infections. Nineteen studies were found, including only one randomised controlled study. Data in the literature on combined therapeutic regimens with rifampicin are limited and refer mostly to uncontrolled studies. Therefore, the real clinical benefit of using rifampicin-containing therapies for the treatment of gram-negative multiresistant bacteria in terms of clinical outcome and survival rates still needs to be assessed.
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Affiliation(s)
- C M J Drapeau
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases 'L. Spallanzani', Via Portuense, 292-00149 Rome, Italy
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Intratracheal colistin sulfate for BALB/c mice with early pneumonia caused by carbapenem-resistant Acinetobacter baumannii. Crit Care Med 2009; 37:2590-5. [PMID: 19623044 DOI: 10.1097/ccm.0b013e3181a0f8e1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES : To study the efficacy of intratracheal colistin sulfate therapy in a murine model of acute pneumonia caused by a clinical CRAB strain, Ab396. Colistin therapy has currently achieved a favorable outcome in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) infections, but parenteral colistin may have limited therapeutic efficacy for CRAB pneumonia. DESIGN : A controlled, in vivo experimental study. SETTING : Research laboratory of a medical center. SUBJECTS : Female BALB/c mice. INTERVENTIONS : The minimal inhibitory concentrations of antibiotics were measured. Acute pneumonia was established by intratracheal inoculation with an inoculum size of 2.5 x 10 colony-forming units Ab396 plus 10% porcine mucin into the lungs of mice, verified by histopathological examinations, and then treated with or without antibiotics. Mice received intratracheal saline treatment as a control group, intraperitoneal administration (IP) imipenem/cilastatin plus sulbactam (IP IS group, 80/80 mg/kg and 40 mg/kg every 8 hrs, n = 30), IP colistin sulfate (IP CS group, 150,000 U/kg every 8 hrs, n = 30), and intratracheal colistin sulfate (intratracheal CS group, 75,000 U/kg every 8 hrs, n = 30) at 2 hrs after intratracheal inoculation of Ab396. MEASUREMENTS AND MAIN RESULTS : The minimal inhibitory concentrations of colistin sulfate, imipenem/cilastatin, or sulbactam for Ab396 were 2 microg/mL, 128 microg/mL, or 32 microg/mL, respectively. Compared with the mice in the control, IP IS, and IP CS groups, those in intratracheal CS group had a significantly favorable outcome at 72 hrs after infection (survival rate = 0%, 10%, 0% and 100%, respectively; all p < .001, log-rank test). Furthermore, intratracheal therapy decreased significantly the bacterial loads in the lungs and normalized the wet lung/body weight ratios in mice with acute pneumonia. CONCLUSIONS : The intratracheal colistin sulfate therapy led to more favorable outcomes than therapies by IP colistin sulfate or imipenem/cilastatin plus sulbactam in mice with early CRAB pneumonia.
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Crane DP, Gromov K, Li D, Søballe K, Wahnes C, Büchner H, Hilton MJ, O’Keefe RJ, Murray CK, Schwarz EM. Efficacy of colistin-impregnated beads to prevent multidrug-resistant A. baumannii implant-associated osteomyelitis. J Orthop Res 2009; 27:1008-15. [PMID: 19173261 PMCID: PMC2810872 DOI: 10.1002/jor.20847] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Osteomyelitis (OM) from multidrug-resistant (MDR) Acinetobacter has emerged in >30% of combat-related injuries in Iraq and Afghanistan. While most of these strains are sensitive to colistin, the drug is not available in bone void fillers for local high-dose delivery. To address this, we developed a mouse model with MDR strains isolated from wounded military personnel. In contrast to S. aureus OM, which is osteolytic and characterized by biofilm in necrotic bone, A. baumannii OM results in blastic lesions that do not contain apparent biofilm. We also found that mice mount a specific IgG response against three proteins (40, 47, and 56 kDa) regardless of the strain used, suggesting that these may be immuno-dominant antigens. PCR for the A. baumannii-specific parC gene confirmed a 100% infection rate with 75% of the MDR strains, and in vitro testing confirmed that all strains were sensitive to colistin. We also developed a real-time quantitative PCR (RTQ-PCR) assay that could detect as few as 10 copies of parC in a sample. To demonstrate the efficacy of colistin prophylaxis in this model, mice were treated with either parenteral colistin (0.2 mg colistinmethate i.m. for 7 days), local colistin (PMMA bead impregnated with 1.0 mg colistin sulfate), or an unloaded PMMA bead control. While the parenteral colistin failed to demonstrate any significant effects versus the placebo, the colistin PMMA bead significantly reduced the infection rate such that only 29.2% of the mice had detectable levels of parC at 19 days (p < 0.05 vs. i.m. colistin and placebo).
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Affiliation(s)
- Daniel P. Crane
- The Center for Musculoskeletal Research, University of Rochester, Rochester, NY
| | - Kirill Gromov
- The Center for Musculoskeletal Research, University of Rochester, Rochester, NY
- The Department of Orthopedics, Aarhus University Hospital, Aarhus, Denmark
| | - Dan Li
- The Center for Musculoskeletal Research, University of Rochester, Rochester, NY
| | - Kjeld Søballe
- The Department of Orthopedics, Aarhus University Hospital, Aarhus, Denmark
| | - Christian Wahnes
- Research & Development, Heraeus Medical GmbH, Wehrheim (Germany)
| | - Hubert Büchner
- Research & Development, Heraeus Medical GmbH, Wehrheim (Germany)
| | - Matthew J. Hilton
- The Center for Musculoskeletal Research, University of Rochester, Rochester, NY
| | - Regis J. O’Keefe
- The Center for Musculoskeletal Research, University of Rochester, Rochester, NY
| | - Clinton K. Murray
- Infectious Disease Service, Dept. of Medicine, Brooke Army Medical Center, Fort Sam Houston, San Antonio, TX
| | - Edward M. Schwarz
- The Center for Musculoskeletal Research, University of Rochester, Rochester, NY
- To whom correspondence should be addressed: Dr. Edward M. Schwarz, The Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, Phone 585-275-3063, FAX 585-756-4727, Edward
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Bassetti M, Righi E, Esposito S, Petrosillo N, Nicolini L. Drug treatment for multidrug-resistant Acinetobacter baumannii infections. Future Microbiol 2009; 3:649-60. [PMID: 19072182 DOI: 10.2217/17460913.3.6.649] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Acinetobacter baumannii has emerged in the last decades as a major cause of healthcare-associated infections and nosocomial outbreaks. Multidrug-resistant (MDR) A. baumannii is a rapidly emerging pathogen in healthcare settings, where it causes infections that include bacteremia, pneumonia, meningitis, and urinary tract and wound infections. Antimicrobial resistance poses great limits for therapeutic options in infected patients, especially if the isolates are resistant to the carbapenems. Other therapeutic options include sulbactam, aminoglycosides, polymixyns and tigecycline. The discovery of new therapies coupled with the development of controlled clinical trial antibiotic testing combinations and the prevention of transmission of MDR Acinetobacter infection are essential to face this important hospital problem.
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Affiliation(s)
- Matteo Bassetti
- Clinica Malattie Infettive, Azienda Ospedaliera Universitaria San Martino, Largo R Benzi 10, 16132 Genova, Italy.
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69
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Aoki N, Tateda K, Kikuchi Y, Kimura S, Miyazaki C, Ishii Y, Tanabe Y, Gejyo F, Yamaguchi K. Efficacy of colistin combination therapy in a mouse model of pneumonia caused by multidrug-resistant Pseudomonas aeruginosa. J Antimicrob Chemother 2009; 63:534-42. [DOI: 10.1093/jac/dkn530] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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70
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Karageorgopoulos DE, Falagas ME. Current control and treatment of multidrug-resistant Acinetobacter baumannii infections. THE LANCET. INFECTIOUS DISEASES 2009; 8:751-62. [PMID: 19022191 DOI: 10.1016/s1473-3099(08)70279-2] [Citation(s) in RCA: 296] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Institutional outbreaks caused by Acinetobacter baumannii strains that have acquired multiple mechanisms of antimicrobial drug resistance constitute a growing public-health problem. Because of complex epidemiology, infection control of these outbreaks is difficult to attain. Identification of potential common sources of an outbreak, through surveillance cultures and epidemiological typing studies, can aid in the implementation of specific control measures. Adherence to a series of infection control methods including strict environmental cleaning, effective sterilisation of reusable medical equipment, attention to proper hand hygiene practices, and use of contact precautions, together with appropriate administrative guidance and support, are required for the containment of an outbreak. Effective antibiotic treatment of A baumannii infections, such as ventilator-associated pneumonia and bloodstream infections, is also of paramount importance. Carbapenems have long been regarded as the agents of choice, but resistance rates have risen substantially in some areas. Sulbactam has been successfully used in the treatment of serious A baumannii infections; however, the activity of this agent against carbapenem-resistant isolates is decreasing. Polymyxins show reliable antimicrobial activity against A baumannii isolates. Available clinical reports, although consisting of small-sized studies, support their effectiveness and mitigate previous concerns for toxicity. Minocycline, and particularly its derivative, tigecycline, have shown high antimicrobial activity against A baumannii, though relevant clinical evidence is still scarce. Several issues regarding the optimum therapeutic choices for multidrug-resistant A baumannii infections need to be clarified by future research.
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71
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Lee CH, Wu CL. An Update on the Management Of Hospital-Acquired Pneumonia in the Elderly. INT J GERONTOL 2008. [DOI: 10.1016/s1873-9598(09)70007-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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72
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Song JY, Cheong HJ, Lee J, Sung AK, Kim WJ. Efficacy of monotherapy and combined antibiotic therapy for carbapenem-resistant Acinetobacter baumannii pneumonia in an immunosuppressed mouse model. Int J Antimicrob Agents 2008; 33:33-9. [PMID: 18835761 DOI: 10.1016/j.ijantimicag.2008.07.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 07/03/2008] [Accepted: 07/10/2008] [Indexed: 11/17/2022]
Abstract
Acinetobacter baumannii is an important cause of nosocomial infection with increasing carbapenem resistance. The aim of this study was to compare the efficacy of colistin+rifampicin and imipenem+rifampicin combinations with that of several other antibiotic regimens against carbapenem-resistant A. baumannii pneumonia using an immunosuppressed mouse model. Three different A. baumannii strains with diverse resistance mechanisms (OXA-51-, IMP-1- and VIM-2-type beta-lactamases) were used. Among the monotherapy regimens, only rifampicin significantly reduced the bacterial load in lungs 24 h after infection with the OXA-51-producing strain. Addition of rifampicin to either imipenem or colistin yielded synergistic results after 48 h. Rifampicin was bactericidal against the IMP-1-producing strain, and only the imipenem+rifampicin combination yielded synergistic effects. In contrast, rifampicin alone was not effective against the VIM-2-producing strain, but the imipenem+rifampicin combination was bacteriostatic even at 24 h post-infection. Tigecycline and amikacin were not effective against any of the three strains. Rifampicin-based combinations were effective against A. baumannii bacteraemia and improved survival regardless of the strain type. Contrary to the similar minimum inhibitory concentration results, the antibacterial effects of rifampicin were quite different according to the strains; a tailored antibiotic strategy must be considered in treatment. Addition of rifampicin to either imipenem or colistin would be effective.
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Affiliation(s)
- Joon Young Song
- Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea
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73
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Petrosillo N, Ioannidou E, Falagas M. Colistin monotherapy vs. combination therapy: evidence from microbiological, animal and clinical studies. Clin Microbiol Infect 2008; 14:816-27. [DOI: 10.1111/j.1469-0691.2008.02061.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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74
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Abstract
The global emergence of multidrug-resistant gram-negative bacilli has spurred a renewed interest in polymyxins. Once discarded due to concerns regarding nephrotoxicity and neurotoxicity, polymyxins now hold an important role in the antibiotic armamentarium. However, more reliable information is needed to determine the optimal dosing of these agents. Also, unanswered questions regarding in vitro testing remain, including questions regarding the reliability of automated systems and the establishment of appropriate breakpoints for defining susceptibility. Most contemporary clinical studies examining the use of these agents have involved patients with infections due to multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii strains. It has been reassuring that polymyxin therapy for resistant bacteria has resulted in clinical responses and toxicity rates similar to those for carbapenem therapy for susceptible isolates. While most surveillance studies demonstrated high rates of susceptibility, several reports noted the emergence of polymyxin-resistant nosocomial pathogens. Polymyxins have assumed an important antibiotic niche for therapy for hospital-acquired infections; further studies defining the optimal use of these agents will likely extend the duration of their clinical usefulness.
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75
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Abstract
Acinetobacter baumannii has emerged as a highly troublesome pathogen for many institutions globally. As a consequence of its immense ability to acquire or upregulate antibiotic drug resistance determinants, it has justifiably been propelled to the forefront of scientific attention. Apart from its predilection for the seriously ill within intensive care units, A. baumannii has more recently caused a range of infectious syndromes in military personnel injured in the Iraq and Afghanistan conflicts. This review details the significant advances that have been made in our understanding of this remarkable organism over the last 10 years, including current taxonomy and species identification, issues with susceptibility testing, mechanisms of antibiotic resistance, global epidemiology, clinical impact of infection, host-pathogen interactions, and infection control and therapeutic considerations.
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76
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Maragakis LL, Perl TM. Acinetobacter baumannii: epidemiology, antimicrobial resistance, and treatment options. Clin Infect Dis 2008; 46:1254-63. [PMID: 18444865 DOI: 10.1086/529198] [Citation(s) in RCA: 667] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Multidrug-resistant Acinetobacter baumannii is recognized to be among the most difficult antimicrobial-resistant gram-negative bacilli to control and treat. Increasing antimicrobial resistance among Acinetobacter isolates has been documented, although definitions of multidrug resistance vary in the literature. A. baumannii survives for prolonged periods under a wide range of environmental conditions. The organism causes outbreaks of infection and health care-associated infections, including bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection. Antimicrobial resistance greatly limits the therapeutic options for patients who are infected with this organism, especially if isolates are resistant to the carbapenem class of antimicrobial agents. Because therapeutic options are limited for multidrug-resistant Acinetobacter infection, the development or discovery of new therapies, well-controlled clinical trials of existing antimicrobial regimens and combinations, and greater emphasis on the prevention of health care-associated transmission of multidrug-resistant Acinetobacter infection are essential.
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Affiliation(s)
- Lisa L Maragakis
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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77
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Song JY, Lee J, Heo JY, Noh JY, Kim WJ, Cheong HJ, Hwang IS. Colistin and rifampicin combination in the treatment of ventilator-associated pneumonia caused by carbapenem-resistant Acinetobacter baumannii. Int J Antimicrob Agents 2008; 32:281-4. [PMID: 18650070 DOI: 10.1016/j.ijantimicag.2008.04.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 04/15/2008] [Accepted: 04/15/2008] [Indexed: 11/19/2022]
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78
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Rat pneumonia and soft-tissue infection models for the study of Acinetobacter baumannii biology. Infect Immun 2008; 76:3577-86. [PMID: 18541654 DOI: 10.1128/iai.00269-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a bacterial pathogen of increasing medical importance. Little is known about its mechanisms of pathogenesis, and safe reliable agents with predictable activity against A. baumannii are presently nonexistent. The availability of relevant animal infection models will facilitate the study of Acinetobacter biology. In this report we tested the hypothesis that the rat pneumonia and soft-tissue infection models that our laboratory had previously used for studies of extraintestinal pathogenic Escherichia coli were clinically relevant for A. baumannii. Advantages of these models over previously described models were that the animals were not rendered neutropenic and they did not receive porcine mucin with bacterial challenge. Using the A. baumannii model pathogen 307-0294 as the challenge pathogen, the pneumonia model demonstrated all of the features of infection that are critical for a clinically relevant model: namely, bacterial growth/clearance, an ensuing host inflammatory response, acute lung injury, and, following progressive bacterial proliferation, death due to respiratory failure. We were also able to demonstrate growth of 307-0294 in the soft-tissue infection model. Next we tested the hypothesis that the soft-tissue infection model could be used to discriminate between the inherent differences in virulence of various A. baumannii clinical isolates. The ability of A. baumannii to grow and/or be cleared in this model was dependent on the challenge strain. We also hypothesized that complement is an important host factor in protecting against A. baumannii infection in vivo. In support of this hypothesis was the observation that the serum sensitivity of various A. baumannii clinical isolates in vitro roughly paralleled their growth/clearance in the soft-tissue infection model in vivo. Lastly we hypothesized that the soft-tissue infection model would serve as an efficient screening mechanism for identifying gene essentiality for drug discovery. Random mutants of 307-0294 were initially screened for lack of growth in human ascites in vitro. Selected mutants were subsequently used for challenge in the soft-tissue infection model to determine if the disrupted gene was essential for growth in vivo. Using this approach, we have been able to successfully identify a number of genes essential for the growth of 307-0294 in vivo. In summary, these models are clinically relevant and can be used to study the innate virulence of various Acinetobacter clinical isolates and to assess potential virulence factors, vaccine candidates, and drug targets in vivo and can be used for pharmacokinetic and chemotherapeutic investigations.
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79
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Abstract
Acinetobacter is a formidable challenge to managing critically ill patients. This pathogen's ability to rapidly develop antimicrobial resistance to all currently available antimicrobial agents is concerning because increasing data support attributable mortality to these bacteria when associated with hospitalized patients with comorbidities and severe illness. The role of dual therapy is currently unclear and might be associated with increased toxicities without proven synergy or ability to prevent the development of resistance. Infection control and antibiotic control measures might have the greatest impact on these bacteria. Continued efforts are needed to develop new antimicrobial agents against this pathogen and assess the ideal currently available agents.
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Affiliation(s)
- Clinton K Murray
- Infectious Disease Service, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, TX 78234, USA.
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80
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Vila J, Pachón J. Therapeutic options for Acinetobacter baumannii infections. Expert Opin Pharmacother 2008; 9:587-99. [PMID: 18312160 DOI: 10.1517/14656566.9.4.587] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Acinetobacter baumannii is an important cause of nosocomial infections, mainly in patients in intensive care units. This microorganism, although with slight differences depending on the country, presents resistance to multiple antimicrobial agents, occasionally including resistance to colistin: hence, it can be considered the paradigm of nosocomial multiresistant bacteria. This review analyzes the evolution of antimicrobial resistance and the molecular bases associated with the increase in antimicrobial resistance, as well as the current treatment of Acinetobacter infections. Although controversy remains, the pooled data suggest that infections by A. baumannii may be associated with considerable attributable mortality. Moreover, in cases of pneumonia and bacteraemia, inappropriate treatment is associated with, among other factors, mortality. Therefore, treatment should be carefully considered.
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Affiliation(s)
- Jordi Vila
- Hospital Clinic, Department of Clinical Microbiology, Villarroel, 170; 08036 Barcelona, Spain.
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83
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Dijkshoorn L, Nemec A, Seifert H. An increasing threat in hospitals: multidrug-resistant Acinetobacter baumannii. Nat Rev Microbiol 2007; 5:939-51. [PMID: 18007677 DOI: 10.1038/nrmicro1789] [Citation(s) in RCA: 1274] [Impact Index Per Article: 74.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Since the 1970s, the spread of multidrug-resistant (MDR) Acinetobacter strains among critically ill, hospitalized patients, and subsequent epidemics, have become an increasing cause of concern. Reports of community-acquired Acinetobacter infections have also increased over the past decade. A recent manifestation of MDR Acinetobacter that has attracted public attention is its association with infections in severely injured soldiers. Here, we present an overview of the current knowledge of the genus Acinetobacter, with the emphasis on the clinically most important species, Acinetobacter baumannii.
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Affiliation(s)
- Lenie Dijkshoorn
- Department of Infectious Diseases C5-P, Leiden University Medical Centre, Albinusdreef 2, P.O. BOX 9600, 2300 RC Leiden, The Netherlands.
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84
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Lee NY, Wang CL, Chuang YC, Yu WL, Lee HC, Chang CM, Wang LR, Ko WC. Combination Carbapenem-Sulbactam Therapy for Critically Ill Patients with Multidrug-ResistantAcinetobacter baumanniiBacteremia: Four Case Reports and an In Vitro Combination Synergy Study. Pharmacotherapy 2007; 27:1506-11. [DOI: 10.1592/phco.27.11.1506] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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85
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Tripodi MF, Durante-Mangoni E, Fortunato R, Utili R, Zarrilli R. Comparative activities of colistin, rifampicin, imipenem and sulbactam/ampicillin alone or in combination against epidemic multidrug-resistant Acinetobacter baumannii isolates producing OXA-58 carbapenemases. Int J Antimicrob Agents 2007; 30:537-40. [PMID: 17851050 DOI: 10.1016/j.ijantimicag.2007.07.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 07/05/2007] [Indexed: 10/22/2022]
Abstract
This study evaluated the activity of colistin, rifampicin, imipenem and sulbactam/ampicillin alone or in combination against nine epidemic multidrug-resistant Acinetobacter baumannii isolates producing OXA-58 carbapenemase in Naples, Italy. The isolates were susceptible to colistin but differed in their resistance to imipenem and rifampicin. Time-kill studies showed a bactericidal effect for colistin but not for imipenem, rifampicin or sulbactam/ampicillin used as single agents. Synergism was observed with combinations of rifampicin+imipenem or sulbactam/ampicillin for all isolates and with colistin+rifampicin for isolates showing higher minimum inhibitory concentrations for rifampicin. Combined use of the antimicrobials tested may provide good therapeutic options for OXA-58 carbapenemase-producing A. baumannii infections.
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86
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Perez F, Hujer AM, Hujer KM, Decker BK, Rather PN, Bonomo RA. Global challenge of multidrug-resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2007; 51:3471-84. [PMID: 17646423 PMCID: PMC2043292 DOI: 10.1128/aac.01464-06] [Citation(s) in RCA: 834] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Federico Perez
- Division of Infectious Diseases and HIV Medicine, University Hospitals, Case Medical Centers, Cleveland, OH, USA
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87
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Li J, Nation RL, Owen RJ, Wong S, Spelman D, Franklin C. Antibiograms of multidrug-resistant clinical Acinetobacter baumannii: promising therapeutic options for treatment of infection with colistin-resistant strains. Clin Infect Dis 2007; 45:594-8. [PMID: 17682994 DOI: 10.1086/520658] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Accepted: 05/07/2007] [Indexed: 11/03/2022] Open
Abstract
Multidrug-resistant Acinetobacter baumannii infection has presented a global medical challenge. The antibiograms of paired colistin-susceptible and -resistant strains revealed increased susceptibility of colistin-resistant strains to most tested antibiotics, including those that are active against only gram-positive bacteria. Synergy between colistin and rifampicin was observed in the colistin-susceptible strains. The ability to form biofilm in the colistin-resistant strains was significantly lower (P<.001) than in the parent strains. Our study provides valuable information for potential expansion of our current therapeutic options against colistin-resistant A. baumannii infection.
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Affiliation(s)
- Jian Li
- Facility for Anti-infective Drug Development and Innovation, Victorian College of Pharmacy, Monash University, Parkville, Victoria, Australia.
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88
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Song JY, Kee SY, Hwang IS, Seo YB, Jeong HW, Kim WJ, Cheong HJ. In vitro activities of carbapenem/sulbactam combination, colistin, colistin/rifampicin combination and tigecycline against carbapenem-resistant Acinetobacter baumannii. J Antimicrob Chemother 2007; 60:317-22. [PMID: 17540672 DOI: 10.1093/jac/dkm136] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES To determine the in vitro activities and interactions of imipenem, colistin and tigecycline with old antibacterial agents against carbapenem-resistant Acinetobacter baumannii. METHODS Forty-three carbapenem-resistant A. baumannii isolates from the intensive care unit of a university hospital were collected and their MICs of imipenem, colistin and tigecycline were determined. With eight randomly selected carbapenem-resistant isolates, an in vitro time-kill study was performed for the evaluation of antibacterial activity of colistin, tigecycline, imipenem/sulbactam and colistin/rifampicin. RESULTS The time-kill study of colistin demonstrated bactericidal activity against A. baumannii at concentrations of 4xMIC and 8xMIC, whereas tigecycline showed bacteriostatic activity at all concentrations. The combination regimens of imipenem/sulbactam and colistin/rifampicin were synergistic and bactericidal at 1xMIC. CONCLUSIONS Imipenem/sulbactam combination, colistin and tigecycline showed good in vitro activities against carbapenem-resistant A. baumannii isolates. Even though colistin is bactericidal against carbapenem-resistant A. baumannii, the colistin/rifampicin combination is more warranted in order to be certain.
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Affiliation(s)
- Joon Young Song
- Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
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89
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Tan TY, Ng LSY, Tan E, Huang G. In vitro effect of minocycline and colistin combinations on imipenem-resistant Acinetobacter baumannii clinical isolates. J Antimicrob Chemother 2007; 60:421-3. [PMID: 17540671 DOI: 10.1093/jac/dkm178] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES The study investigated the effect of colistin and minocycline when tested singly and in combination against Acinetobacter baumannii. METHODS Thirteen unrelated imipenem-resistant A. baumannii clinical isolates were included in the study. MICs of colistin sulphate and minocycline were determined by broth macrodilution and Etest. Organisms were also tested against the two antibiotics singly and in combination using time-kill methods and an Etest-based method. RESULTS Neither colistin nor minocycline when tested alone demonstrated bactericidal activity. However, the combination of colistin and minocycline demonstrated bactericidal activity against most of the isolates tested. At 24 h, the combination of antibiotics demonstrated synergy in 12 of the 13 isolates by time-kill methods. None of the isolates demonstrated synergy by Etest methods. CONCLUSIONS The combination of colistin and minocycline was found to be bactericidal and synergistic against A. baumannii by time-kill methods. There was no agreement between time-kill and Etest methods for synergy testing.
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Affiliation(s)
- Thean Yen Tan
- Laboratory Medicine Services, Changi General Hospital, 2 Simei Street 3, Singapore 529889.
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90
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Documento de Consenso sobre pneumonia nosocomial11Sociedade Portuguesa de Pneumologia e Sociedade Portuguesa de Cuidados Intensivos / Portuguese Society of Pulmonology and Intensive Care Society,22O presente documento é simultaneamente publicado na Revista Portuguesa de Medicina Intensiva (2007; 14(1):7-30) / This work is published simultaneously in the Portuguese Journal of Intensive Care Medicine (2007; 14(1):7-30). REVISTA PORTUGUESA DE PNEUMOLOGIA 2007. [DOI: 10.1016/s0873-2159(15)30360-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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91
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Diaz E, Muñoz E, Agbaht K, Rello J. Management of ventilator-associated pneumonia caused by multiresistant bacteria. Curr Opin Crit Care 2007; 13:45-50. [PMID: 17198048 DOI: 10.1097/mcc.0b013e3280121816] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE OF REVIEW The inappropriate choice of antibiotics (in nearly one third of episodes) is the most important risk factor for death. Traditionally, a narrow-spectrum drug was used first, and the most potent drugs were reserved for subsequent use. RECENT FINDINGS As multidrug resistance increases in the intensive care unit in patients treated for nosocomial pneumonia, costs, mortality, and morbidity are rising. Although methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii are frequently considered together, they have different virulence, risk factors and susceptibilities, requiring different antimicrobial choices. Assessment of clinical resolution should be differentiated in the presence of acute lung injury. In the absence of biochemical markers, oxygenation and core temperature should guide therapeutic decisions. SUMMARY As ventilator-associated pneumonia increases, empiric therapy should be based on local pathogen etiology and antibiotic resistant patterns. A new approach to consider is to start with a high-dose, broad-spectrum antibiotic and then tailor the individual therapy based on microbiological results and clinical resolution. With the use of broad-spectrum antibiotics available in empiric therapy tailored after reassessment of the patient, there is hope for reducing costs, length of stay and mortality whereas the emergence of resistance will be minimized.
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Affiliation(s)
- Emili Diaz
- Critical Care Department, Joan XXIII University Hospital, University Rovira & Virgili. Institut Pere Virgili, Tarragona. Spain.
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92
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Poirel L, Nordmann P. Carbapenem resistance in Acinetobacter baumannii: mechanisms and epidemiology. Clin Microbiol Infect 2006; 12:826-36. [PMID: 16882287 DOI: 10.1111/j.1469-0691.2006.01456.x] [Citation(s) in RCA: 703] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The increasing trend of carbapenem resistance in Acinetobacter baumannii worldwide is a concern since it limits drastically the range of therapeutic alternatives. Metallo-beta-lactamases (VIM, IMP, SIM) have been reported worldwide, especially in Asia and western Europe, and confer resistance to all beta-lactams except aztreonam. The most widespread beta-lactamases with carbapenemase activity in A. baumannii are carbapenem-hydrolysing class D beta-lactamases (CHDLs) that are mostly specific for this species. These enzymes belong to three unrelated groups of clavulanic acid-resistant beta-lactamases, represented by OXA-23, OXA-24 and OXA-58, that can be either plasmid- or chromosomally-encoded. A. baumannii also possesses an intrinsic carbapenem-hydrolysing oxacillinase, the expression of which may vary, that may play a role in carbapenem resistance. In addition to beta-lactamases, carbapenem resistance in A. baumannii may also result from porin or penicillin-binding protein modifications. Several porins, including the 33-kDa CarO protein, that constitute a pore channel for influx of carbapenems, might be involved in carbapenem resistance.
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Affiliation(s)
- L Poirel
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, South-Paris Medical School, University Paris XI, Le Kremlin-Bicêtre, France.
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93
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Koulenti D, Rello J. Hospital-acquired pneumonia in the 21st century: a review of existing treatment options and their impact on patient care. Expert Opin Pharmacother 2006; 7:1555-69. [PMID: 16872259 DOI: 10.1517/14656566.7.12.1555] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Hospital-acquired pneumonia is a common nosocomial infection, with significant morbidity and mortality, and represents a major therapeutic challenge to clinicians. The therapeutic approach must be patient-oriented and institution-specific. The specific risk factors of each patient, such as previous antibiotic exposure, underlying diseases, length of hospital stay and the local patterns of antimicrobial resistance, should guide physicians in their decision of the initial optimal empirical therapy. Delays in the initiation or inappropriate/inadequate initial therapy are related to increased mortality and worse outcomes. In responding patients, as soon as culture data are available, efforts should be made to change the initial broad spectrum antibiotic regimen to a more targeted one (de-escalation). The optimal duration of treatment is a matter of debate, but courses longer than 1 week are rarely justified.
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MESH Headings
- Acinetobacter Infections/drug therapy
- Acinetobacter Infections/etiology
- Acinetobacter Infections/mortality
- Administration, Inhalation
- Aminoglycosides/administration & dosage
- Aminoglycosides/therapeutic use
- Anti-Bacterial Agents/administration & dosage
- Anti-Bacterial Agents/therapeutic use
- Carbapenems/administration & dosage
- Carbapenems/therapeutic use
- Cephalosporins/administration & dosage
- Cephalosporins/therapeutic use
- Cross Infection/drug therapy
- Cross Infection/etiology
- Cross Infection/mortality
- Drug Administration Schedule
- Drug Resistance, Multiple, Bacterial
- Drug Therapy, Combination
- Humans
- Methicillin Resistance
- Pneumonia, Bacterial/drug therapy
- Pneumonia, Bacterial/etiology
- Pneumonia, Bacterial/mortality
- Pneumonia, Staphylococcal/drug therapy
- Pneumonia, Staphylococcal/etiology
- Pneumonia, Staphylococcal/mortality
- Practice Guidelines as Topic
- Pseudomonas Infections/drug therapy
- Pseudomonas Infections/etiology
- Pseudomonas Infections/mortality
- Respiration, Artificial/adverse effects
- Vancomycin/administration & dosage
- Vancomycin/therapeutic use
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Affiliation(s)
- Despoina Koulenti
- Critical Care Department, Joan XXIII University Hospital/ Institut Pere Virgili, Mallafre Guasch, 4, 43007 Tarragona, Spain.
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94
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Abstract
PURPOSE OF REVIEW Recent articles of clinical and investigational interest on Gram-negative pneumonia, particularly hospital-acquired and ventilator-associated pneumonia, are reviewed. RECENT FINDINGS The high rate of respiratory infections due to Gram-negative bacteria in late-onset ventilator-associated pneumonia has been repeatedly documented. The predominant pathogens are Pseudomonas aeruginosa and Acinetobacter baumannii. On the other hand, the frequency of Gram-negative bacteria in community-acquired pneumonia and in early-onset ventilator-associated pneumonia is increasing. Patients with risk factors for infection with resistant pathogens should initially receive a combination therapy that covers a broad spectrum, and, as soon as the pathogen and the susceptibilities are available, treatment should be simplified to a more targeted one (with the possible exception of P. aeruginosa pneumonia). Adequate dosing is of great importance and the use of pharmacodynamic/pharmacokinetic principles when prescribing antibiotics increases effectiveness. The optimal duration of therapy remains unknown; several studies have supported the use of shorter courses of treatment. Alternative treatment approaches (e.g. vaccines) are under investigation. SUMMARY The increasing frequency of resistant Gram-negative bacteria and the shortage of newer antibiotics in the pipeline with activity against Gram-negative bacteria is of concern. Early effective antimicrobial treatment is a key for the resolution of infection and improved survival.
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Affiliation(s)
- Despoina Koulenti
- Critical Care Department, Joan XXIII University Hospital, University Rovira y Virgili/Institut PereVirgili, Tarragona, Spain
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95
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Poirel L, Nordmann P. Résistance aux β-lactamines chez Acinetobacter baumannii : évolution et émergence de nouveaux mécanismes. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1294-5501(06)70805-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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96
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Joly-Guillou ML, Bergogne-Bérézin E. Les bactéries du genre Acinetobacter revisitées : leur importance actuelle. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1294-5501(06)70804-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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97
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Wareham DW, Bean DC. In vitro activities of polymyxin B, imipenem, and rifampin against multidrug-resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2006; 50:825; author reply 825-6. [PMID: 16436759 PMCID: PMC1366933 DOI: 10.1128/aac.50.2.825-826.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- D. W. Wareham
- Centre for Infectious DiseaseInstitute of Cell and Molecular ScienceBarts and The LondonQueen Mary's School of Medicine and Dentistry4 Newark StreetLondon E1 2AT, United Kingdom
- Phone: (44) 207 7882 2317, E-mail:
| | - D. C. Bean
- Centre for Infectious DiseaseInstitute of Cell and Molecular ScienceBarts and The LondonQueen Mary's School of Medicine and Dentistry4 Newark StreetLondon E1 2AT, United Kingdom
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98
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Motaouakkil S, Charra B, Hachimi A, Nejmi H, Benslama A, Elmdaghri N, Belabbes H, Benbachir M. Colistin and rifampicin in the treatment of nosocomial infections from multiresistant Acinetobacter baumannii. J Infect 2006; 53:274-8. [PMID: 16442632 DOI: 10.1016/j.jinf.2005.11.019] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 11/09/2005] [Accepted: 11/18/2005] [Indexed: 01/02/2023]
Abstract
INTRODUCTION The increased incidence of nosocomial infections by multi-drug resistant Acinetobacter baumannii creates demand on the application of some combinations of older antimicrobials on that species. We conducted the present observational study to evaluate the efficacy of intravenous and aerosolized colistin combined with rifampicin in the treatment of critically patients with nosocomial infections caused by multiresistant A. baumannii. PATIENTS AND METHODS Critically ill patients with nosocomial infections caused by A. baumannii resistant to all antibiotics except colistin in a medical intensive care unit. Diagnosis of infection was based on clinical data and isolation of bacteria. The bacterial susceptibilities to colistin were tested. Clinical response to colistin+rifampicin was evaluated. RESULTS Twenty-six patients (43.58+/-18.29 years, Acute Physiology and Chronic Health Evaluation II Score (APACHE II): 6.35+/-2.99), of whom 16 cases of nosocomial pneumonia treated by aerosolized colistin (1x10(6) IU three times/day) associated with intravenous rifampicin (10 mg/kg every 12h), nine cases of bacteraemia treated by intravenous colistin (2x10(6)IU three times/day) associated with intravenous rifampicin (10 mg/kg every 12h) in which three cases associated with ventilator associated pneumonia and one case of nosocomial meningitis treated by intrathecal use of colistin associated with intravenous rifampicin. The clinical evolution was favourable for all ill patients. Concerning side effects, we have noticed a moderate hepatic cytolysis in three patients. CONCLUSION This is the first clinical report of colistin combined with rifampicin for treatment of A. baumannii infection. Despite the lack of a control group and the limited number of patients, the results seem to be encouraging.
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Affiliation(s)
- Said Motaouakkil
- Medical Intensive Care Unit, Ibn Rochd University Hosptial, Casablanca, Morocco.
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99
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Cisneros-Herreros JM, Garnacho-Montero J, Pachón-Ibáñez ME. Neumonía nosocomial por Acinetobacter baumannii. Enferm Infecc Microbiol Clin 2005; 23 Suppl 3:46-51. [PMID: 16854341 DOI: 10.1157/13091220] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acinetobacter baumannii is a significant cause of nosocomial pneumonia, especially late ventilator-associated pneumonia. In Spain, A. baumannii is the third leading pathogen after Pseudomonas aeruginosa and Staphylococcus aureus. Risk factors for pneumonia due to A. baumannii are head injury, neurosurgery, acute respiratory distress syndrome, aspiration, and previous antibiotic therapy. Definitive diagnosis requires respiratory samples and invasive techniques with quantitative cultures to differentiate true infections from simple colonizations. The crude mortality of patients with ventilator-associated A. baumannii pneumonia is high, although the attributable mortality is controversial. Adequate empirical antimicrobial therapy of A. baumannii pneumonia is a protective factor, even though the therapeutic options are often limited. The treatment of choice is imipenem and sulbactam may be considered an acceptable alternative. Nowadays, colistin is the treatment of choice in A. baumannii pneumonia caused by panresistant strains. The associations of imipenem and rifampin or imipenem and sulbactam may be acceptable alternatives to colistin in infections caused by these strains. Surveillance measures are essential to eradicate this multidrug-resistant pathogen in outbreaks and reduce the number of episodes in endemic situations. Although these measures are important throughout the hospital, intensive care units are especially high-risk areas.
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100
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Abstract
PURPOSE OF REVIEW Acinetobacter baumannii-calcoaceticus complex has become a serious nosocomial pathogen due to its persistence in the hospital environment and its broad antimicrobial resistance patterns. This review summarizes the most recent literature pertaining to the clinical management of infections with this bacteria emphasizing in-vitro antimicrobial resistance patterns and antimicrobial efficacy in animals and humans. RECENT FINDINGS Although this pathogen can be associated with an elevated crude mortality, it only contributes to this mortality in a subset of high-risk patients. Determining in-vitro activity of antimicrobial agents can be problematic due to conflicting results sometimes obtained through different testing methods. There is no simple answer as to the most appropriate antimicrobial therapy secondary to lack of adequate studies. Imipenem/cilastatin, amikacin, ampicillin/sulbactam, colistin, rifampin, and tetracyclines are typically active against these bacteria. It is also not clear if combination therapy is more effective than monotherapy. In cases in which A. baumannii-calcoaceticus complex bacteria are resistant to all available agents, we have prolonged infusion times, increased drug dose, and altered route of instillation, such as nebulized therapy for pulmonary infections with mixed results. A primary goal of A. baumannii-calcoaceticus complex management should be to prevent initial colonization and subsequent infection by adequate infection control. SUMMARY The A. baumannii-calcoaceticus complex continues to play a significant role in our healthcare systems. Prompt and adequate therapy with agents having in-vitro activity is required once it is established that the bacteria represents infection and not colonization. Aggressive infection control policies should be enforced when this pathogen is identified.
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Affiliation(s)
- Clinton K Murray
- Infectious Disease Service, Department of Medicine, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, TX 78234, USA.
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