Epidemiology of Bloodstream Infections Caused by Acinetobacter baumannii and Impact of Drug Resistance to both Carbapenems and Ampicillin-Sulbactam on Clinical Outcomes

Chopra, Teena; Marchaim, Dror; Awali, Reda; Krishna, Amar; Johnson, Paul C.; Tansek, Ryan; Chaudary, Khawar; Lephart, Paul; Slim, Jessica; Hothi, Jatinder; Ahmed, Harris; Pogue, Jason M.; Zhao, Jing; Kaye, Keith S.

doi:10.1128/aac.01520-13

Cited by 64 publications

(54 citation statements)

References 29 publications

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“…The hallmark of the XDR phenotype is carbapenem resistance. CRAB strains tend to be XDR-that is, resistant to all other antibiotics, with the exception of polymyxins, tigecycline, and sometimes aminoglycosides (50,52,53). NHSN and Eurofins surveillance data highlight that carbapenem resistance occurs in more than 50% of A. baumannii ICU isolates in the United States, by far the highest rate of resistance for any pathogen surveyed (27,181,182).…”

Section: Antibiotic Resistance Drives Outcomesmentioning

confidence: 99%

“…To circumvent the intrinsic resistance of many mouse strains to A. baumannii infection, artificial models have been used, such as infecting mice intraperitoneally (a clinically irrelevant route of entry) or mixing the inoculum with porcine mucin as a foreign body that inhibits the host's immune system from rapidly clearing the organism (59,60). In addition, mice are often made neutropenic prior to infection even though neutropenia is not a common risk factor for infections caused by A. baumannii, and the vast majority of patients infected with A. baumannii have neither deficiency in leukocyte numbers nor overt defects in leukocyte function (25,(50)(51)(52)(53)(61)(62)(63)(64)(65)(66)(67)(68). Results from such models must be interpreted circumspectly given the unclear applicability to clinical disease.…”

Section: Models Of Infectionmentioning

confidence: 99%

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Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

et al. 2017

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SUMMARY Acinetobacter is a complex genus, and historically, there has been confusion about the existence of multiple species. The species commonly cause nosocomial infections, predominantly aspiration pneumonia and catheter-associated bacteremia, but can also cause soft tissue and urinary tract infections. Community-acquired infections by Acinetobacter spp. are increasingly reported. Transmission of Acinetobacter and subsequent disease is facilitated by the organism's environmental tenacity, resistance to desiccation, and evasion of host immunity. The virulence properties demonstrated by Acinetobacter spp. primarily stem from evasion of rapid clearance by the innate immune system, effectively enabling high bacterial density that triggers lipopolysaccharide (LPS)–Toll-like receptor 4 (TLR4)-mediated sepsis. Capsular polysaccharide is a critical virulence factor that enables immune evasion, while LPS triggers septic shock. However, the primary driver of clinical outcome is antibiotic resistance. Administration of initially effective therapy is key to improving survival, reducing 30-day mortality threefold. Regrettably, due to the high frequency of this organism having an extreme drug resistance (XDR) phenotype, early initiation of effective therapy is a major clinical challenge. Given its high rate of antibiotic resistance and abysmal outcomes (up to 70% mortality rate from infections caused by XDR strains in some case series), new preventative and therapeutic options for Acinetobacter spp. are desperately needed.

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Section: Antibiotic Resistance Drives Outcomesmentioning

confidence: 99%

Section: Models Of Infectionmentioning

confidence: 99%

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

et al. 2017

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“…With the wide use of immunosuppressive drugs, the increase in invasion surgeries and the development of intensive care technology (2), an increasing number of A. baumannii infections have been detected. Multi-drug resistance and the amplification of resistance to A. baumannii have increased the mortality rate in the clinic (3). Resistance to antibiotics against A. baumannii mostly occurs due to the loss of membrane proteins, active efflux mechanisms, changes in penicillin-binding proteins (PBPs) and the production of various enzymes, amongst which the production of β-lactamases plays an important role in the resistance to β-lactam antibiotics (5).…”

Section: Introductionmentioning

confidence: 99%

Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance

Liu

2015

Experimental and Therapeutic Medicine

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Abstract. The aim of the present study was to determine the prevalence and related drug resistance of AmpC β-lactamases in Acinetobacter baumannii in tertiary-level hospitals in the Xuzhou region in China. A total of 134 clinical isolates of non-repetitive Acinetobacter baumannii were collected from different hospitals in the Xuzhou region, and multiplex polymerase chain reaction (PCR) was employed to determine the genotype of AmpC. The PCR products were purified and sequenced. The susceptibility to antibiotics was tested using the biometrics automated microbiological-assay system, VITEK-2. Amongst the 134 isolated strains, 96 strains were found to produce AmpC β-lactamases, and the positive rate was 72%, all of which carried acinetobacter-derived cephalosporinase (ADC) type AmpC resistance genes. The drug sensitivity tests indicated that the positive Acinetobacter baumannii strains were resistant to the majority of extended-spectrum β-lactam antibiotics, but were only sensitive to polymyxin. In conclusion, the incidence of AmpC enzymes in Acinetobacter baumannii strains in tertiary-level hospitals in the Xuzhou area is relatively high, and resistance to the majority of extendedspectrum β-lactam antibiotics may be related to the ADC type of AmpC.

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“…In prior studies that rigorously controlled for severity of illness, A. baumannii infection was not independently associated with increased mortality, raising the possibility that this organism is a marker of increased severe underlying illness rather than an independent predictor of mortality. (5,6) In the current study, nearly 30% of infected patients (16/56) died within 24 hours of diagnosis despite reportedly being on effective Abbreviations: CRAB, carbapenem-resistant Acinetobacter baumannii; CRKP, carbapenem-resistant Klebsiella pneumoniae; LT, liver transplantation; MDR, multidrug resistant; PFGE, pulsed-field gel electrophoresis.Address reprint requests to …”

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confidence: 99%

The evolving threat of carbapenem‐resistant infections after liver transplantation: The case of A cinetobacter baumannii

Pereira

Uhlemann

2016

Liver Transpl

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Postoperative bacterial infections have shifted from predominantly gram-positive to gram-negative organisms in liver transplantation (LT) recipients.(1) Of concern is the increasing incidence of difficult to treat multidrug resistant (MDR) infections due to extended spectrum b-lactamases and carbapenemresistant Enterobacteriacae. The high mortality rate (40%-70%) associated with post-LT carbapenemresistant Klebsiella pneumoniae (CRKP) infections is a sobering example of the impact of MDR infection in this population. (2,3) In this issue of Liver Transplantation, Freire et al. (4) provide compelling evidence that an additional organism, carbapenem-resistant Acinetobacter baumannii (CRAB), is also associated with very high morbidity and mortality after LT. In a prospective 2-year cohort study, the authors routinely surveyed colonization with A. baumannii at 3 body sites (rectum, throat, and axilla) immediately prior to LT and weekly thereafter until hospital discharge. Of the 196 LT recipients evaluated, 105 (54%) were found to have acquired CRAB, most often (n 5 81) during the post-LT period. Similarly, although 60 recipients developed CRAB infection, the majority of these (n 5 56) occurred post-LT and usually early in the post-LT course (median time, 9 days; range, 1-43 days). The likelihood of post-LT CRAB acquisition increased with retransplantation within 60 days after LT and prior use of piperacillintazobactam or a carbapenem. Most notably, 60-day mortality in the recipients with CRAB infection was 46.4%. Risk factors associated with 60-day mortality included LT for acute liver failure, need for post-LT dialysis, prolonged cold ischemia time, and a trend toward significance for pre-LT CRAB acquisition. Molecular typing by pulsed-field gel electrophoresis (PFGE) analysis revealed that 71% of infected recipients had 1 predominant strain, suggesting a clonal outbreak in the LT unit or across the hospital. Importantly, a series of infection control measures including weekly surveillance cultures, contact precautions, contact isolation of CRAB-colonized patients, hand hygiene training, and systematic discussions of CRAB cases attributed to the unit resulted in the incidence of CRAB acquisition dropping from 12.2/1000 patient-days in 2009 to 5.5/1000 patient-days by 2014.Although these findings are remarkable, some aspects of the conclusions should be interpreted with caution. For instance, this study was performed during an outbreak, perhaps limiting its applicability. It also remains unclear if this was solely an outbreak in the LT unit or represented a hospital-wide outbreak. In addition, although the crude 60-day mortality was very high, determining the attributable mortality of post-LT CRAB infections is difficult. In prior studies that rigorously controlled for severity of illness, A. baumannii infection was not independently associated with increased mortality, raising the possibility that this organism is a marker of increased severe underlying illness rather than an independent predictor of mortality. (5,...

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Epidemiology of Bloodstream Infections Caused by Acinetobacter baumannii and Impact of Drug Resistance to both Carbapenems and Ampicillin-Sulbactam on Clinical Outcomes

Cited by 64 publications

References 29 publications

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance

The evolving threat of carbapenem‐resistant infections after liver transplantation: The case of A cinetobacter baumannii

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