Molecular characterization of Acinetobacter baumannii isolated from Iraqi hospital environment

Al-Kadmy, Israa M.S.; Ali, Alaa Naseer Mohammed; Salman, Isam Noori; Khazaal, Saba Saadoon

doi:10.1016/j.nmni.2017.10.010

Cited by 51 publications

(46 citation statements)

References 27 publications

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“…GcL is a rare thermophilic representative within MLLs, with a half‐life of (152.5±10) min at 75 °C . Herein, we show that GcL is a proficient lactonase, which makes it a potent inhibitor of biofilm formation for the pathogen Acinetobacter baumannii that uses C6‐AHL for signaling . Because structural variations of AHLs confer signal specificity, it is critical to elucidate substrate preferences.…”

Section: Introductioncontrasting

confidence: 79%

The Structural Determinants Accounting for the Broad Substrate Specificity of the Quorum Quenching Lactonase GcL

et al. 2019

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Quorum quenching lactonases are enzymes capable of hydrolyzing lactones, including N‐acyl homoserine lactones (AHLs). AHLs are molecules known as signals in bacterial communication dubbed quorum sensing. Bacterial signal disruption by lactonases was previously reported to inhibit behavior regulated by quorum sensing, such as the expression of virulence factors and the formation of biofilms. Herein, we report the enzymatic and structural characterization of a novel lactonase representative from the metallo‐β‐lactamase superfamily, dubbed GcL. GcL is a broad spectrum and highly proficient lactonase, with kcat/KM values in the range of 104 to 106 m−1 s−1. Analysis of free GcL structures and in complex with AHL substrates of different acyl chain length, namely, C4‐AHL and 3‐oxo‐C12‐AHL, allowed their respective binding modes to be elucidated. Structures reveal three subsites in the binding crevice: 1) the small subsite where chemistry is performed on the lactone ring; 2) a hydrophobic ring that accommodates the amide group of AHLs and small acyl chains; and 3) the outer, hydrophilic subsite that extends to the protein surface. Unexpectedly, the absence of structural accommodation for long substrate acyl chains seems to relate to the broad substrate specificity of the enzyme.

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Section: Introductioncontrasting

confidence: 79%

The Structural Determinants Accounting for the Broad Substrate Specificity of the Quorum Quenching Lactonase GcL

et al. 2019

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“…This may be due to their ability to adhere to the tools Or the hands of workers in the hospital, which facilitates transmission between patients and patients who are asleep, and certainly can not ignore the horizontal movement referred to bacteria from the skin or infected organs to the blood, leading to bacteremia. Our results were consistent with previous local studies (Authman et al, 2018) (AL-Kadmy et al, 2018As well in a different country such as (Basri et al, 2015) (Momtaz et al, 2015) .…”

Section: Outer Membrane Adhesions and Integritysupporting

confidence: 94%

“…After centrifugation, supernatant was used as template DNA . PCR mixture of composed from 12.5 of GoTaq ® Green Master Mix 2x USA promega , 5 µl template DNA, 1 µl primers (for each) inal concentration (0.6pmol/µl),and nuclease free water up to 25 µl (5.5 µl) (AL-Kadmy et al, 2018).…”

Section: Temple Preparation For Pcrmentioning

confidence: 99%

Molecular analysis of multi –drug resistant acintobacter baumannii isolated in baghdad hospital

Ridha¹,

Ali²,

Jassim³

2019

ijrps

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Qurum sense is regulatory systems that enable bacteria to expretion for a specific set of genes by making collective decisions and regulation of virulence factors of pathogenic Acintobacter baumannii, the prevalence of carbapenem resistance among (8) different antibiotic groups pattern. In the MDR index, all isolates showed high MDR, ranged from (6-21) antibiotics. MDR index is between (0.29-1.0).Quantitative biofilm production assay showed that 118/124(95.1%)of isolates were biofilm-formers. Detection of QS genes showed that (97.6%)121/124,(98.3%)122\124 and (4.8%)of isolates carried luxR, rhlI and rhIR genes, respectivelly. All isolates possess rhIR gene are isolated from child meningococcal patients and characterized by the strong biofilm formation. Identification of abaI gene in A.baumannii producing the QS signal molecules detected in124\124(100%). The current study revealed a strong relationship between Q.S genes luxR,rhII,rhIR and oxacillinases presence OXA23, OXA69. While a strong negative correlation between OXA48 and OXA69 with the rhIR gene. All isolates carried Integron I(n=124)(100%) with a significant presence of (luxR, rhII) genes, while INT2,3 had a highly significant level with rhIR. Noteworthy, (n=105) 84.7% of OXA51 positive isolates have carried ISAbal-blaOXA-51, whereas all isolates which have OXA23 carried ISAbal-blaOXA-23(n=65)52.4% most of them revealed IMP&MEM resistance phenotype. Insertion sequence(ISAbal-blaOXA-51) showed significant correlation with luxR, rhII genes, while there was no correlation among ISAbal25, ISAbal, ISAbal25-blaADC and luxR, rhII. Positive correlation recorded with all IS with rhIR, except ISAbal-blaADC.ads-a gene was observed in 77/124(62.1%) of isolates, which associated with aminoglycoside resistance, and included within the 93 XDR isolates. Studied isolates showed the same prevelance rate for ompA, smpA which was122\124(98.4%) of isolates.

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“…There are limited reports about the investigation of A. baumannii in the hospital environment from Iran and other countries of the region (13)(14)(15)(16). We screened surfaces and equipment of five hospitals and observed a high frequency (53.1%) of CRAB isolates which were simultaneously resistant to some tested antimicrobial agents.…”

Section: Discussionmentioning

confidence: 99%

Genetic Diversity of OXA Producing Carbapenem-Resistant Acinetobacter baumannii from Environment of Tertiary Hospitals in Central Iran

Rostami

Mehrban

Ghourchian

et al. 2020

Arch Clin Infect Dis

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Background:The hospital environment usually involves in cross-colonization and/or outbreaks of carbapenem-resistant Acinetobacter baumannii (CRAB). This study aims to identify genetic diversity of environmental Acinetobacter baumannii (A. baumannii) isolates based on OXA-type carbapenems. Objectives: It was intended to identify the environmental source of A. baumannii strains to control future infections and ongoing outbreaks. Methods: Swab samples were collected from equipment, fluids and surfaces of intensive care units of five hospitals (H1 to H5). The susceptibility of the isolates was defined through disk diffusion method. blaOXA-51, blaOXA-58, blaOXA-23, and blaOXA-24 genes were detected by multiplex polymerase chain reaction (PCR) . Genetic diversity was investigated using ERIC-PCR. Mean values were compared using an Independent samples t-test. Results:The mean number of Gram-negative bacilli colony per sample was significantly higher in moist surfaces (1.9 ± 2.37) than in dry surfaces and medical equipment (P < 0.05). Among 32 A. baumannii isolates, 17 (53.1%) were classified as CRAB, 13 (40.6%) as multidrug resistant (MDR) and six (18.8%) as extremely drug resistant (XDR) phenotypes. The isolates showed the most susceptibility to tigecycline (81.3%) and doxycycline (81.3%). Totally, 10 isolates (31.3%) carried blaOXA-23 and one isolate carried blaOXA-58, but none contained blaOXA-24. Typing of the strains provided seven single types (ST) and nine clusters (A-I). Two isolates in cluster B (different surfaces of H4) and two in cluster I (from ventilators of H3 and H1) were designated as common type (CT). In H4 and H1, different isolates belonging to different clusters were recovered from bed sheet and baby sink bath, respectively. Conclusions: Clonally-related blaOXA-23 positive CRABs occurred in the environment, especially on moist surfaces of hospitals. The distribution of the same clones in different hospitals may point to expansion of a specific clone which increases the risk of crosscolonization of vulnerable patients.

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Molecular characterization of Acinetobacter baumannii isolated from Iraqi hospital environment

Cited by 51 publications

References 27 publications

The Structural Determinants Accounting for the Broad Substrate Specificity of the Quorum Quenching Lactonase GcL

The Structural Determinants Accounting for the Broad Substrate Specificity of the Quorum Quenching Lactonase GcL

Molecular analysis of multi –drug resistant acintobacter baumannii isolated in baghdad hospital

Genetic Diversity of OXA Producing Carbapenem-Resistant Acinetobacter baumannii from Environment of Tertiary Hospitals in Central Iran

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