scholarly journals Insights on carbapenem-resistant Acinetobacter baumannii

2021 ◽  
Vol 65 (1) ◽  
pp. 85-92
Author(s):  
Matthew Gavino Donadu ◽  
Stefania Zanetti ◽  
Ádám László Nagy ◽  
Ibrahim Barrak ◽  
Márió Gajdács
Keyword(s):  
Public Health ◽  
Acinetobacter Baumannii ◽  
Efflux Pump ◽  
Public Health Issue ◽  
Carbapenem Resistant ◽  
Wide Range ◽  
Effective Choice ◽  
Phenotypic Methods ◽  
Resistance Rates ◽  
Critical Public Health

Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen, which may be a causative agent in a wide-range of human pathologies. Carbapenems are usually considered the last safe and effective choice of drugs for the treatment of Gram-negative infections. The emergence of carbapenem-resistant A. baumannii (CRAB) is a critical public health issue as they leave clinicians with limited therapeutic options. In this study, phenotypic methods were used to characterize sixty-two (n = 62) A. baumannii isolates, which were included based on their suspected non-susceptibility to meropenem. Minimum inhibitory concentrations (MICs) of meropenem, levofloxacin, gentamicin, sulfamethoxazole/trimethoprim, tigecycline were determined using E-tests, while colistin MICs were determined using broth microdilution. The isolates were subjected to the modified Hodge test (MHT), the modified carbapenem-inactivation method (mCIM) and the imipenem/EDTA combined disk test (CDT). Efflux pump overexpression was studied using agar plates containing phenylalanine-arginine β-naphthylamide (PAβN). Assessment of biofilm-formation was carried out using the crystal violet tube-adherence method. 64.5% of the strains showed meropenem MICs in the resistant range (>8 mg/L), resistance rates were similarly high to the other tested antibiotics. The MHT and mCIM assay were positive in 79.0% and 67.7% of cases, respectively; the presence of an MBL was suggested for 29.0% of isolates. Efflux-pump overexpression was seen in 12.9% of isolates. 54.8% of the isolates were characterized as strong biofilm-producers. Microbiology laboratories have an important role in differentiating the distinct mechanisms by which these pathogens develop the CRAB phenotype, as plasmid-borne carbapenemases are significant from the standpoint of public health microbiology.

scholarly journals Carbapenemase-Producing, Carbapenem-Resistant Acinetobacter baumannii: Summary of CDC Consultations, 2017–2019

2020 ◽  
Vol 41 (S1) ◽  
pp. s151-s152
Author(s):  
Lauren Epstein ◽  
Alicia Shugart ◽  
David Ham ◽  
Snigdha Vallabhaneni ◽  
Richard Brooks ◽  
...  
Keyword(s):  
Public Health ◽  
Acinetobacter Baumannii ◽  
Median Number ◽  
Skilled Nursing Facilities ◽  
Nursing Facilities ◽  
Skilled Nursing ◽  
Healthcare Facilities ◽  
Carbapenem Resistant ◽  
Number Of Patients ◽  
Single Facility

Background: Carbapenemase-producing carbapenem-resistant Acinetobacter baumannii (CP-CRAB) are a public health threat due to potential for widespread dissemination and limited treatment options. We describe CDC consultations for CP-CRAB to better understand transmission and identify prevention opportunities. Methods: We defined CP-CRAB as CRAB isolates with a molecular test detecting KPC, NDM, VIM, or IMP carbapenemases or a plasmid-mediated oxacillinase (OXA-23, OXA-24/40, OXA-48, OXA-58, OXA-235/237). We reviewed the CDC database of CP-CRAB consultations with health departments from January 1, 2017, through June 1, 2019. Consultations were grouped into 3 categories: multifacility clusters, single-facility clusters, and single cases. We reviewed the size, setting, environmental culturing results, and identified infection control gaps for each consultation. Results: We identified 29 consultations involving 294 patients across 19 states. Among 9 multifacility clusters, the median number of patients was 12 (range, 2–87) and the median number of facilities was 2 (range, 2–6). Among 9 single-facility clusters, the median number of patients was 5 (range, 2–50). The most common carbapenemase was OXA-23 (Table 1). Moreover, 16 consultations involved short-stay acute-care hospitals, and 6 clusters involved ICUs and/or burn units. Also, 8 consultations involved skilled nursing facilities. Environmental sampling was performed in 3 consultations; CP-CRAB was recovered from surfaces of portable, shared equipment (3 consultations), inside patient rooms (3 consultations) and nursing stations (2 consultations). Lapses in environmental cleaning and interfacility communication were common across consultations. Among 11 consultations for single CP-CRAB cases, contact screening was performed in 7 consultations and no additional CP-CRAB was identified. All 4 patients with NDM-producing CRAB reported recent international travel. Conclusions: Consultations for clusters of oxacillinase-producing CP-CRAB were most often requested in hospitals and skilled nursing facilities. Healthcare facilities and public health authorities should be vigilant for possible spread of CP-CRAB via shared equipment and the potential for CP-CRAB spread to connected healthcare facilities.Funding: NoneDisclosures: None

scholarly journals Triclosan resistance in clinical isolates of Acinetobacter baumannii

2009 ◽  
Vol 58 (8) ◽  
pp. 1086-1091 ◽  
Author(s):  
Yagang Chen ◽  
Borui Pi ◽  
Hua Zhou ◽  
Yunsong Yu ◽  
Lanjuan Li
Keyword(s):  
Acinetobacter Baumannii ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Active Efflux ◽  
Low Level ◽  
High Level ◽  
Resistance Rates ◽  
Triclosan Resistance

The susceptibility to triclosan of 732 clinical Acinetobacter baumannii isolates obtained from 25 hospitals in 16 cities in China from December 2004 to December 2005 was screened by using an agar dilution method. Triclosan MICs ranged between 0.015 and 16 mg l−1, and the MIC90 was 0.5 mg l−1, lower than the actual in-use concentration of triclosan. Twenty triclosan-resistant isolates (MICs ≥1 mg l−1) were characterized by antibiotic susceptibility, clonal relatedness, fabI mutation, fabI expression, and efflux pump phenotype and expression to elucidate the resistance mechanism of A. baumannii to triclosan. The resistance rates of triclosan-resistant isolates to imipenem, levofloxacin, amikacin and tetracycline were higher than those of triclosan-sensitive isolates. Triclosan resistance was artificially classified as low level (MICs 1–2 mg l−1) or high level (MICs ≥4 mg l−1). High-level triclosan resistance could be explained by a Gly95Ser mutation of FabI, whilst wild-type fabI was observed to be overexpressed in low-level resistant isolates. Active efflux did not appear to be a major reason for acquired triclosan resistance, but acquisition of resistance appeared to be dependent on a background of intrinsic triclosan efflux.

scholarly journals Dissemination of imipenem-resistant Acinetobacter baumannii strains carrying the ISAba1–bla OXA-23 genes in a Chinese hospital

2007 ◽  
Vol 56 (8) ◽  
pp. 1076-1080 ◽  
Author(s):  
Hua Zhou ◽  
Bo-Rui Pi ◽  
Qing Yang ◽  
Yun-Song Yu ◽  
Ya-Gang Chen ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Acinetobacter Baumannii ◽  
Environmental Isolates ◽  
Hospital Units ◽  
Wide Range ◽  
Polymyxin E ◽  
Encoding Gene ◽  
Almost All ◽  
Resistance Rates ◽  
Encoding Genes

An outbreak of 95 clinical infections with imipenem-resistant Acinetobacter baumannii in a Chinese hospital was investigated and the carbapenemase-encoding genes and their relationship with ISAba1 of these and a further 16 isolates recovered from the intensive care unit (ICU) environment were analysed. Almost all isolates were resistant to a wide range of antimicrobials; the lowest resistance rates were found for polymyxin E (17.1 %), cefoperazone/sulbactam (30.6 %) and ampicillin/sulbactam (67.6 %). Six pattern types defined by DNA macrorestriction patterns were distinguished among the clinical isolates with dissemination of pattern A (50 isolates) to patients in seven hospital units and pattern B (35 isolates) to eight units; the environmental isolates from ICUs were also of pattern A. All isolates were positive for the bla OXA-66 and bla OXA-23 genes. The OXA-23-encoding gene was located 34 bp downstream of ISAba1. No plasmids were detected and conjugal transfer of resistance was not demonstrated. The bla OXA-23 probe hybridized with 200 and 220 kb ApaI chromosomal fragments for type patterns A and B, respectively.

scholarly journals Impact of an Intervention to Control Imipenem-Resistant Acinetobacter baumannii and Its Resistance Mechanisms: An 8-Year Survey

2021 ◽  
Vol 11 ◽  
Author(s):  
Lida Chen ◽  
Pinghai Tan ◽  
Jianming Zeng ◽  
Xuegao Yu ◽  
Yimei Cai ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Acinetobacter Baumannii ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Multi Drug Resistance ◽  
Minimal Inhibitory Concentrations ◽  
Resistance Rates ◽  
The Impact

BackgroundThis study aimed to examine the impact of an intervention carried out in 2011 to combat multi-drug resistance and outbreaks of imipenem-resistant Acinetobacter baumannii (IRAB), and to explore its resistance mechanism.MethodsA total of 2572 isolates of A. baumannii, including 1673 IRAB isolates, were collected between 2007 and 2014. An intervention was implemented to control A. baumannii resistance and outbreaks. Antimicrobial susceptibility was tested by calculating minimal inhibitory concentrations (MICs), and outbreaks were typed using pulsed-field gel electrophoresis (PFGE). Resistance mechanisms were explored by polymerase chain reaction (PCR) and whole genome sequencing (WGS).ResultsFollowing the intervention in 2011, the resistance rates of A. baumannii to almost all tested antibiotics decreased, from 85.3 to 72.6% for imipenem, 100 to 80.8% for ceftriaxone, and 45.0 to 6.9% for tigecycline. The intervention resulted in a decrease in the number (seven to five), duration (8–3 months), and departments (five to three) affected by outbreaks; no outbreaks occurred in 2011. After the intervention, only blaAMPC (76.47 to 100%) and blaTEM–1 (75.74 to 96.92%) increased (P < 0.0001); whereas blaGES–1 (32.35 to 3.07%), blaPER–1 (21.32 to 1.54%), blaOXA–58 (60.29 to 1.54%), carO (37.50 to 7.69%), and adeB (9.56 to 3.08%) decreased (P < 0.0001). Interestingly, the frequency of class B β-lactamase genes decreased from 91.18% (blaSPM–1) and 61.03% (blaIMP–1) to 0%, while that of class D blaOXA–23 increased to 96.92% (P < 0.0001). WGS showed that the major PFGE types causing outbreaks each year (type 01, 11, 18, 23, 26, and 31) carried the same resistance genes (blaKPC–1, blaADC–25, blaOXA–66, and adeABC), AdeR-S mutations (G186V and A136V), and a partially blocked porin channel CarO. Meanwhile, plasmids harboring blaOXA–23 were found after the intervention.ConclusionThe intervention was highly effective in reducing multi-drug resistance of A. baumannii and IRAB outbreaks in the long term. The resistance mechanisms of IRAB may involve genes encoding β-lactamases, efflux pump overexpression, outer membrane porin blockade, and plasmids; in particular, clonal spread of blaOXA–23 was the major cause of outbreaks. Similar interventions may also help reduce bacterial resistance rates and outbreaks in other hospitals.

scholarly journals Rescued chlorhexidine activity by resveratrol against carbapenem-resistant Acinetobacter baumannii via down-regulation of AdeB efflux pump

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243082
Author(s):  
Uthaibhorn Singkham-in ◽  
Paul G. Higgins ◽  
Dhammika Leshan Wannigama ◽  
Parichart Hongsing ◽  
Tanittha Chatsuwan
Keyword(s):  
Acinetobacter Baumannii ◽  
Ethidium Bromide ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Intracellular Accumulation ◽  
Efflux Pump Inhibitor ◽  
Carbapenem Resistant ◽  
Efflux Pump Inhibition ◽  
Synergistic Mechanism ◽  
Time Kill

The aim of this study was to determine the activity and synergistic mechanisms of resveratrol in combination with chlorhexidine against carbapenem-resistant Acinetobacter baumannii clinical isolates. The activity of resveratrol plus antimicrobial agents was determined by checkerboard and time-kill assay against carbapenem-resistant A. baumannii isolated from patients at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Overexpression of efflux pumps that mediates chlorhexidine susceptibility was characterized by the ethidium bromide accumulation assay. The effect of resveratrol on the expression of efflux pump genes (adeB, adeJ, adeG abeS, and aceI) and the two-component regulators, adeR and adeS was determined by RT-qPCR. The combination of resveratrol and chlorhexidine resulted in strong synergistic and bactericidal activity against carbapenem-resistant A. baumannii. Up-regulation of adeB and aceI was induced by chlorhexidine. However, the addition of resveratrol increased chlorhexidine susceptibility with increased intracellular accumulation of ethidium bromide in A. baumannii indicating that resveratrol acts as an efflux pump inhibitor. Expression of adeB was significantly reduced in the combination of resveratrol with chlorhexidine indicating that resveratrol inhibits the AdeB efflux pump and restores chlorhexidine effect on A. baumannii. In conclusion, reduced adeB expression in A. baumannii was mediated by resveratrol suggesting that AdeB efflux pump inhibition contributes to the synergistic mechanism of resveratrol with chlorhexidine. Our finding highlights the potential importance of resveratrol in clinical applications.

scholarly journals Uncovering the gut microbiota as a reservoir of ST11 hypervirulent KPC-2-producing Klebsiella pneumoniaeUncovering the gut microbiota as a reservoir of ST11 hypervirulent KPC-2-producing Klebsiella pneumoniae

2019 ◽  
Author(s):  
Beiwen Zheng ◽  
Hao Xu ◽  
Tao Lv ◽  
Lihua Guo ◽  
Xiao Yu ◽  
...  
Keyword(s):  
Public Health ◽  
Gut Microbiota ◽  
Carbapenem Resistance ◽  
Underlying Mechanism ◽  
Public Health Issue ◽  
Virulence Plasmids ◽  
Carbapenem Resistant ◽  
Health Community ◽  
Surgical History ◽  
Genomic Characterization

Abstract Background: The emergence and spread of ST11 carbapenem-resistant, hypervirulent K. pneumonia (ST11-CR-HvKP) in China generated great concern from the public health community. The identification of ST11-CR-HvKP strain is expected to become a serious public health issue in China, considering the carbapenem resistance and virulence had converged in an epidemic clone. However, the underlying mechanism that enables its wide dissemination in China remains unclear.Results: Here, we investigate the prevalence of carbapenemase-producing Enterobacteriaceae (CPE) carriage by inpatients in a teaching hospital over a 1-year period, to identify ST11-CR-HvKP reservoirs, and to understand the transmission of these pathogens across healthcare networks. We identified a high colonization prevalence of CPE (12.4%) among inpatients with diarrhea. Correlations were detected between antibiotic exposure, surgical history, and being CPE positive. A genomic investigation of 65 CRKP isolates indicated a shared bacterial population among various wards. Maximum-likelihood phylogenetic tree demonstrated that these isolates were partitioned into three major clades. An analysis of the wzi locus revealed three different K types (KL105, KL47, and K64) among the ST11 isolates, indicating genetic diversity among these isolates. Our review of the cases showed that these patients had no contact with each other, indicating nosocomial transmission. Genetic and sequence mapping revealed complexity in the existence of virulence plasmids and resistance plasmids in the ST11-CRKP isolates. These data indicate that this process was more complicated than was earlier anticipated, as it may have involved multiple ST11 K. pneumoniae lineages and a variety of virulence plasmids. Conclusions: Collectively, this work represents the first evidence of gut microbiota may act as the source of ST11-CR-HvKP isolate. Active surveillance approaches, particularly in ICUs based on the results of this study, should be implemented to combat the spread of ST11-CR-HvKP and to improve patient outcomes. Key words: gut microbiota; hypervirulent; KPC-2; reservoir; genomic characterization

scholarly journals Modified CIM-Test As a Useful Tool to Detect Carbapenemase Activity Among Extensively Drug- Resistant Klebsiella Pneumoniae, Escherichia Coli and Acinetobacter Baumannii

2021 ◽  
Author(s):  
Abed Zahedi bialvaei ◽  
Alireza Dolatyar Dehkharghani ◽  
Farhad Asgari ◽  
Firouzeh Shamloo ◽  
Parisa Eslami ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Acinetobacter Baumannii ◽  
Sensitivity And Specificity ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Polymerase Chain ◽  
Phenotypic Methods ◽  
Encoding Genes ◽  
Positive Results

Abstract Background Timely detection of carbapenemases is essential for developing strategies to control the spread of infections by carbapenem-resistant isolates. The purpose of our study was to determine the epidemiology of carbapenemase genes among carbapenem resistant isolates of Acinetobacter baumannii, Klebsiella pneumoniae and Escherichia coli and to compare efficacy of modified Hodge Test (MHT), Carba NP and modified carbapenem inactivation method (mCIM) tests. Methods A total of 122 carbapenem-resistant clinical isolates including 77 K. pneumoniae, 39 A. baumannii, and six E. coli were collected from hospitalized patients. Three phenotypic methods, including MHT, Carba NP test and mCIM were used for investigation of carbapenemase production. In addition, polymerase chain reaction (PCR) was performed to detect carbapenemase encoding genes. Results The sensitivity and specificity of the MHT were 75.0% and 100% respectively. In addition, CarbaNP displayed 80.8% sensitivity and 100% specificity, whereas the sensitivity and specificity were 90.4% and 100% for the mCIM test, respectively. Among carbapenem-resistant isolates, 70, 84 and 87 isolates exhibited positive results according to MHT, CarbaNP test and mCIM, respectively. PCR indicated the presence of one or more carbapenemase genes in 119 of carbapenem-resistant isolates, with blaKPC and blaVIM being the most commonly encountered. Co-production of ‘KPC and VIM’, ‘KPC and IMP’ and ‘KPC and OXA-48’ was detected in nine, seven and three isolates, respectively. Conclusion Our results confirm that the mCIM test is a useful tool for the reliable detection of carbapenemases-activity in enterobacterial isolates, especially in clinical microbiological laboratories with limited resources.

scholarly journals One Health or Three? Transmission modelling of Klebsiella isolates reveals ecological barriers to transmission between humans, animals and the environment

2021 ◽  
Author(s):  
Harry A Thorpe ◽  
Ross Booton ◽  
Teemu Kallonen ◽  
Marjorie J Gibbon ◽  
Natacha Couto ◽  
...  
Keyword(s):  
Public Health ◽  
Clinical Environment ◽  
Opportunistic Pathogens ◽  
Klebsiella Species ◽  
Public Health Burden ◽  
Carbapenem Resistant ◽  
Ecological Barriers ◽  
Wide Range ◽  
Rapid Spread ◽  
The City

The Klebsiella group is highly diverse both genetically and ecologically, being commonly recovered from humans, livestock, plants, soil, water, and wild animals. Many species are opportunistic pathogens, and can harbour diverse classes of antimicrobial resistance (AMR) genes. K. pneumoniae is responsible for a high public-health burden, due in part to the rapid spread of health-care associated clones that are non-susceptible to carbapenems. Klebsiella thus represents a highly pertinent taxon for assessing the risk to public health posed by animal and environmental reservoirs. Here we report an analysis of 6548 samples and 3,482 genome sequences representing 15 Klebsiella species sampled over a 15-month period from a wide range of clinical, community, animal and environmental settings in and around the city of Pavia, in the northern Italian region of Lombardy. Despite carbapenem-resistant clones circulating at a high frequency in the hospitals, we find no genotypic or phenotypic evidence for non-susceptibility to carbapenems outside of the clinical environment. The non-random distribution of species and strains across sources point to ecological barriers that are likely to limit AMR transmission. Although we find evidence for occasional transmission between settings, hierarchical modelling and intervention analysis suggests that direct transmission from the multiple non-human (animal and environmental) sources included in our sample accounts for less than 1% of hospital disease, with the vast majority of clinical cases originating from other humans.

scholarly journals A study on clinical profile of typhoid fever in children

2017 ◽  
Vol 4 (3) ◽  
pp. 1067
Author(s):  
Ranganatha A. Devaranavadagi ◽  
Srinivasa S.
Keyword(s):  
Public Health ◽  
Typhoid Fever ◽  
Clinical Manifestations ◽  
Antibiotic Sensitivity ◽  
Public Health Problem ◽  
Public Health Issue ◽  
Common Symptom ◽  
Major Public Health Problem ◽  
Sensitivity Pattern ◽  
Wide Range

Background: Typhoid fever is caused by Salmonella typhi. It is a major public health problem in India. Typhoid fever is endemic in many developing countries. Wide variations in the clinical manifestations of typhoid fever make its diagnosis a challenging task. This study was conducted to understand the wide range of clinical manifestations, complications and antibiotic sensitivity patterns of typhoid fever in children.Methods:Prospectively, 113 children admitted in pediatric unit with confirmed Typhoid fever from September 2015 to December 2016 at KIMS hospital, Bangalore were included. In each case, age, sex, presenting complaint, laboratory investigations and antibiotic sensitivity pattern are collected and analysed.Results: Out of 113 cases, 72 cases (63.8.1%) were males, 41 cases (36.2%) were females. The most common age group was 5-10 years. The most common symptom was fever, seen in 100% cases, followed by anorexia (61%), vomiting (44%) and abdominal pain (18%). The most common sign observed was toxic look in 68% of the cases, followed by coated tongue in 49% and hepatomegaly in 44%. Leucocytopenia was found in 34% of cases. Eosinopenia was found in 39% of cases. Anaemia was found in 16% of cases. Thrombocytopenia was found in 15% of cases. Blood culture was positive in 20% of cases. Use of municipal water for drinking was found in 65% of cases. Outside eating was found in 40% of cases. Unhygienic practices were found in 64% of cases. Duration of hospital stay varied from 3-10 days. No mortality reported.Conclusions:Typhoid fever is most commonly observed with unhygienic practices and eating of unhealthy outside food. This major public health issue can be tackled by bringing awareness among people regarding disease transmission and its various preventive measures. 

scholarly journals Increasing carbapenem resistance due to the clonal dissemination of oxacillinase (OXA-23 and OXA-58)-producing Acinetobacter baumannii: report from the Turkish SENTRY Program sites

2008 ◽  
Vol 57 (12) ◽  
pp. 1529-1532 ◽  
Author(s):  
Deniz Gur ◽  
Volken Korten ◽  
Serhat Unal ◽  
Lalitagauri M. Deshpande ◽  
Mariana Castanheira
Keyword(s):  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Carbapenem Resistance ◽  
Surveillance Program ◽  
Carbapenem Resistant ◽  
Medical Institutions ◽  
Antimicrobial Surveillance ◽  
Resistant Strains ◽  
Resistance Rates ◽  
Encoding Genes

A significant increase in carbapenem-resistance rates among Acinetobacter baumannii isolates collected in two Turkish medical centres was detected in the 2000–2006 period (20–60 %) by the SENTRY Antimicrobial Surveillance Program. Carbapenem-resistant strains from 2006 were evaluated for the presence of encoding genes and epidemic clonality. OXA-58-like and OXA-23-like carbapenemase-producing strains were detected in both medical institutions. Seventeen out of 18 strains from Ankara were positive for bla OXA-58 primers and belonged to the same clone, whilst 26 isolates (25 from Istanbul and one from Ankara) harboured bla OXA-23-like genes and showed identical or similar PFGE patterns. Isolates producing OXA-23-like carbapenemases were more resistant than OXA-58-like carbapenemase producers to non-carbapenem antimicrobial agents. Carbapenem resistance in these institutions was observed to be largely driven by the dissemination of clones producing OXA-type carbapenemases.

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