Colistin resistance in Acinetobacter baumannii isolated from critically ill patients: clinical characteristics, antimicrobial susceptibility and outcome

Background: Acinetobacter baumannii (AB) is increasingly becoming a clinically relevant organism due to the rising number of associated nosocomial infections. The therapeutic options are extremely minimal because of its ability to develop resistance to all available antimicrobials, including colistin (CST). Data on the clinical and microbiological characteristics of colistin-resistant A. baumannii infections remain scarce to date.Methods: In this prospective study, clinical isolates of colistin resistance among Acinetobacter strain was evaluated from the database of Microbiology Laboratory of King Khalid University Hospital, Saudi Arabia.Results: In a total of 142 patients with 136 Acinetobacter isolates, Acintobacter baumannii was the predominant serotype 73% of the isolates and Acinetobacter lwoffii constituted 27% of the isolate .There was 8.5% colistin resistant isolates with colistin E-test MIC >4. The clinical characteristics were determined for colistin resistant Acinetobacter baumannii. All patients were critically ill and 64% of them were hositalized in the Intensive Care Unit (ICU). All patients have been previously given antibiotics. Other associated clinical characteristics included; morbid obesity and sleeve gastrectomy (21 %), mechanical ventilation and central venous catheter (50%). High mortality rate was found(28%).Conclusion: There is an increase of colistin resistance among clinical isolates of Acinetobacter baumannii causing serious infections especially in critically ill patients.Keywords: Acinetobacter baumannii, colistin resistance, clinical characteristics.

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A Prospective Study of Acinetobacter baumannii Complex Isolates and Colistin Susceptibility Monitoring by Mass Spectrometry of Microbial Membrane Glycolipids

Journal of Clinical Microbiology ◽

10.1128/jcm.01100-18 ◽

2018 ◽

Vol 57 (3) ◽

Cited By ~ 4

Author(s):

Lisa M. Leung ◽

Christi L. McElheny ◽

Francesca M. Gardner ◽

Courtney E. Chandler ◽

Sarah L. Bowler ◽

...

Keyword(s):

Mass Spectrometry ◽

Acinetobacter Baumannii ◽

Lipid A ◽

Membrane Lipids ◽

Clinical Isolates ◽

Colistin Resistance ◽

Hospital System ◽

Content Type ◽

Acinetobacter Baumannii Complex ◽

Gram Negative Organisms

ABSTRACT Acinetobacter baumannii is a prevalent nosocomial pathogen with a high incidence of multidrug resistance. Treatment of infections due to this organism with colistin, a last-resort antibiotic of the polymyxin class, can result in the emergence of colistin-resistant strains. Colistin resistance primarily occurs via modifications of the terminal phosphate moieties of lipopolysaccharide-derived lipid A, which reduces overall membrane electronegativity. These modifications are readily identified by mass spectrometry (MS). In this study, we prospectively collected Acinetobacter baumannii complex clinical isolates from a hospital system in Pennsylvania over a 3-year period. All isolates were evaluated for colistin resistance using standard MIC testing by both agar dilution and broth microdilution, as well as genospecies identification and lipid A profiling using MS analyses. Overall, an excellent correlation between colistin susceptibility and resistance, determined by MIC testing, and the presence of a lipid A modification, determined by MS, was observed with a sensitivity of 92.9% and a specificity of 94.0%. Additionally, glycolipid profiling was able to differentiate A. baumannii complex organisms based on their membrane lipids. With the growth of MS use in clinical laboratories, a reliable MS-based glycolipid phenotyping method that identifies colistin resistance in A. baumannii complex clinical isolates, as well as other Gram-negative organisms, represents an alternative or complementary approach to existing diagnostics.

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Colistin-Resistant Acinetobacter Baumannii Bacteremia: A Serious Threat for Critically Ill Patients

Microorganisms ◽

10.3390/microorganisms8020287 ◽

2020 ◽

Vol 8 (2) ◽

pp. 287 ◽

Cited By ~ 4

Author(s):

Georgios Papathanakos ◽

Ioannis Andrianopoulos ◽

Athanasios Papathanasiou ◽

Efthalia Priavali ◽

Despoina Koulenti ◽

...

Keyword(s):

Septic Shock ◽

Acinetobacter Baumannii ◽

Critically Ill ◽

Critically Ill Patients ◽

Clinical Problem ◽

Hospital Infections ◽

Colistin Resistance ◽

Icu Patients ◽

Icu Admission ◽

Comorbidity Index

The prevalence of acinetobacter baumannii (AB) as a cause of hospital infections has been rising. Unfortunately, emerging colistin resistance limits therapeutic options and affects the outcome. The aim of the study was to confirm our clinically-driven hypothesis that intensive care unit (ICU) patients with AB resistant-to-colistin (ABCoR) bloodstream infection (BSI) develop fulminant septic shock and die. We conducted a 28-month retrospective observational study including all patients developing AB infection on ICU admission or during ICU stay. From 622 screened patients, 31 patients with BSI sepsis were identified. Thirteen (41.9%) patients had ABCoR BSI and 18/31 (58.1%) had colistin-susceptible (ABCoS) BSI. All ABCoR BSI patients died; of them, 69% (9/13) presented with fulminant septic shock and died within the first 3 days from its onset. ABCoR BSI patients compared to ABCoS BSI patients had higher mortality (100% vs. 50%, respectively (p = 0.001)), died sooner (p = 0.006), had lower pH (p = 0.004) and higher lactate on ICU admission (p = 0.0001), and had higher APACHE II (p = 0.01) and Charlson Comorbidity Index scores (p = 0.044). In conclusion, we documented that critically ill patients with ABCoR BSI exhibit fulminant septic shock with excessive mortality. Our results highlight the emerging clinical problem of AB colistin resistance among ICU patients.

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Colistin heteroresistance in carbapenem-resistant Acinetobacter baumannii clinical isolates from a Thai university hospital

World Journal of Microbiology and Biotechnology ◽

10.1007/s11274-020-02873-8 ◽

2020 ◽

Vol 36 (7) ◽

Author(s):

Khin Thet Thet ◽

Kamonwan Lunha ◽

Arpasiri Srisrattakarn ◽

Aroonlug Lulitanond ◽

Ratree Tavichakorntrakool ◽

...

Keyword(s):

Acinetobacter Baumannii ◽

Clinical Isolates ◽

University Hospital ◽

Carbapenem Resistant ◽

Thai University

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Molecular characterization of lpxACD and pmrA/B two-component regulatory system in the colistin resistance Acinetobacter baumannii clinical isolates

Gene Reports ◽

10.1016/j.genrep.2020.100952 ◽

2020 ◽

Vol 21 ◽

pp. 100952

Author(s):

Mohammad Reza Kandehkar Ghahraman ◽

Hossein Hosseini-Nave ◽

Omid Azizi ◽

Mohammad Reza Shakibaie ◽

Hamid Reza Mollaie ◽

...

Keyword(s):

Acinetobacter Baumannii ◽

Molecular Characterization ◽

Regulatory System ◽

Clinical Isolates ◽

Colistin Resistance ◽

Two Component

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Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of Acinetobacter baumannii

Infection and Drug Resistance ◽

10.2147/idr.s253440 ◽

2020 ◽

Vol Volume 13 ◽

pp. 1547-1558

Author(s):

Saeed Khoshnood ◽

Mohammad Savari ◽

Effat Abbasi Montazeri ◽

Ahmad Farajzadeh Sheikh

Keyword(s):

Genetic Diversity ◽

Acinetobacter Baumannii ◽

Resistance Genes ◽

Biofilm Formation ◽

Clinical Isolates ◽

Colistin Resistance

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Colistin resistance in Acinetobacter baumannii is driven by multiple genomic traits: Evaluating the role of ISAba1-driven eptA overexpression among Indian isolates

10.1101/2021.01.07.425695 ◽

2021 ◽

Author(s):

Saranya Vijayakumar ◽

Jobin John Jacob ◽

Karthick Vasudevan ◽

Baby Abirami Shankar ◽

Maria Lincy Francis ◽

...

Keyword(s):

Acinetobacter Baumannii ◽

Lipid A ◽

Resistance Mechanisms ◽

Clinical Isolates ◽

Colistin Resistance ◽

Two Component System ◽

Synonymous Mutations ◽

Insertional Inactivation ◽

Indian Isolates

Colistin resistance in Acinetobacter baumannii is mediated by multiple mechanisms. Recently, mutations within pmrAB two component system and overexpression of eptA due to upstream insertion of ISAba1 play a major role. To characterize colistin resistance mechanisms among the clinical isolates of A. baumannii in India. A total of 224 clinical isolates of A. baumannii collected from 2016 to 2019 were included in this study. Mutations within lipid A biosynthesis and pmrAB genes were characterized by Whole Genome Shotgun sequencing. Twenty eight complete genomes were further characterized for insertional inactivation of lpx genes and the association of ISAba1-eptA using hybrid assembly approach. Non-synonymous mutations like M12I in pmrA, A138T and A444V in pmrB and E117K in lpxD were identified. Four of the five colistin resistant A. baumannii isolates had insertion of ISAba1 upstream eptA. No mcr genes were identified. Overall, the present study highlights the diversity of colistin resistance mechanisms in A. baumannii. ISAba1-driven eptA overexpression could be responsible for colistin resistance among Indian isolates of colistin resistant A. baumannii.

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Trends in antimicrobial resistance of Acinetobacter baumannii clinical isolates in a Greek university hospital

10.26226/morressier.56d5ba2cd462b80296c969b6 ◽

2016 ◽

Author(s):

Diamantis Kofteridis

Keyword(s):

Antimicrobial Resistance ◽

Acinetobacter Baumannii ◽

Clinical Isolates ◽

University Hospital

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Decreasing Prevalence of Multidrug-Resistant Acinetobacter Baumannii in Rīga East University Hospital / Multirezistentās Acinetobacter Baumannii Izplatības Mazināšanās Rīgas Austrumu Klīniskajā Universitātes Slimnīcā

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.1515/prolas-2016-0037 ◽

2016 ◽

Vol 70 (4) ◽

pp. 232-236

Author(s):

Māris Liepiņš ◽

Raimonds Sīmanis ◽

Aivars Lejnieks

Keyword(s):

Infection Control ◽

Acinetobacter Baumannii ◽

Venous Catheter ◽

Multidrug Resistant ◽

Control Measures ◽

University Hospital ◽

Hospital Environment ◽

Central Venous ◽

Infection Control Measures ◽

Time Period

Abstract There has been an increasing tendency of infections caused by multidrug-resistant organisms (MDRO), including multidrug-resistant Acinetobacter baumannii (MDRAB), in the Rīga East University Hospital (REUH) during the last decade. Over the last two years (2014-2015), this tendency has reversed and the prevalence of MDRAB has decreased considerably. In this study we assessed the prevalence of MDRAB in intensive care units (ICUs), internal medicine, surgery units and analysed antibiotic sensitivity profiles. In addition, we determined if current infection control measures are preventing further increase of infections caused by MDRAB in REUH. Retrospective Acinetobacter baumannii prevalence data were collected for the period from 2009 until 2012. For the time period from the beginning of 2013 until 2015, after implementing such infection control measures as control of compliance to hand hygiene guidelines, a review of central venous catheter insertion protocols and regular search for sources of MDRAB in hospital environment, prospective follow-up of new cases was conducted. Antimicrobial sensitivity profiles were assessed for the period from 2013 until 2015. Data were processed with the statistical software WHONET 5.5. Bacteria identification and antibiotic susceptibility testing were performed by VITEK 2 compact, BioMerieux, France. The prevalence of MDRAB in the period 2009 to 2013 increased from 71 to 217 cases per year, but from between 2013 (time of implementing infection control measures) and 2015 it decreased to 113 cases in 2015. In the three year period (2013-2015), the proportion of MDRAB causing bloodstream infections (BSI) and central nervous system infections (CNSI) was 15.85% from all identified MDRAB cases. Of the 113 MDRAB infections diagnosed in 2015, BSI was found in 16.81% cases (n = 19). Antibiotic resistance testing showed that colistin is the most effective drug against MDRAB. The majority of Acinetobacter baumannii isolates were resistant to Ampicillin/Sulbactam, Piperacillin/Tazobactam, Ceftazidime, Cefepime, Imipenem, Meropenem, Amikacin, Gentamicin, Tobramycin, and Ciprofloxacin. Over the last two years (2014-2015), prevalence of MDRAB infections decreased considerably. In the time period from 2013 to 2014, resistance of Acinetobacter baumannii increased to imipenem, ciprofloxacin and colistin, while decreased slightly to amikacin. Rigorous infection control measures, such as identification and elimination of new MDRAB sources in environment, review of the central venous catheter insertion protocol and improvements in hand hygiene, are crucial for decreasing distribution of and invasive infections caused by MDRAB in the hospital environment.

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