Antimicrobial Activities and Mechanisms of Carbapenem Resistance in Clinical Isolates of Carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter spp.

Carbapenem resistance mediated by NDM is particularly gruesome as this carbapenemase can hydrolyze a wide range of β-lactam antibiotics. Aim: This study aims to detect NDM mediated carbapenem resistance in clinical isolates of Pseudomonas aeruginosa. Materials and Methods: 50 multi-drug resistant clinical urinary isolates of Pseudomonas aeruginosa from three major hospitals in Khartoum state Sudan; Khartoum Teaching Hospital, Medical Army Hospital and Omdurman teaching hospital, in period from July 2016 to September 2017, were investigated for carbapenem resistance using standard disc diffusion method and underwent real-time PCR to detect carbapenem resistance gene blaNDM. Data were analyzed using IBM SPSS. Results: 60% were positive for the blaNDM, 82% were resistant to Imipenem and 75% of the samples were resistant to Meropenem. Conclusion: The emergence of carbapenem resistance is a global problem that requires earnest attention. To make the suitable preventive measures, the emergence of these genes must be monitored closely. Our findings revealed that carbapenem-resistant due to the gene blaNDM is accounted for 60% of the cases, and due to lack of proper data documentation about the emergence of this gene in Sudan, these cases to the best of our knowledge are the first to be reported in Sudan.

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Molecular Detection of bla OXA-48 Gene Encoding Carbapenem Resistance Pseudomonas aeruginosa Clinical Isolates from Khartoum State Hospitals, Sudan

10.1101/2020.06.22.20137034 ◽

2020 ◽

Author(s):

Doha Omer Ali ◽

Mohamed M.A. Nagla

Keyword(s):

Pseudomonas Aeruginosa ◽

Teaching Hospital ◽

Carbapenem Resistance ◽

Clinical Isolates ◽

Clinical Samples ◽

P Value ◽

Gene Encoding ◽

State Hospitals ◽

Carbapenem Resistant ◽

Different Strains

AbatractCarbapenem resistance in Pseudomonas.aeruginosa is particularly worrisome because this class of β-lactam represents the last therapeutic resource for control of bacterial infection.So this study aimed to detect the frequency of bla OXA-48 resistance gene among Pseudomonas aeruginosa clinical isolates during the period from November 2018 to November 2019.Hundred Pseudomonas aeruginosa clinical isolates, 81 carbapenems (imipenem meropenem) resistant and 19 carbapenems sensitive were collected from Omdurman Teaching Hospital, Fedail Hospital and Soba Teaching Hospital in Khartoum State-Sudan. All isolates were re-identified using conventional bacteriological techniques, their susceptibility to carbapenems were tested using Kirby-Bauer method for confirmation and investigated for the presence of the bla OXA-48 gene using conventional PCR technique.60 (60.0%) out of 100 Pseudomonas aeruginosa clinical isolates were positive for blaOXA-48 gene. Out of 81 carbapenem resistant isolates 54(66.7%) were positive for bla OXA-48 gene, while among the (19) carbapenem sensitive isolates 6 (31.6%) were positive for blaOXA-48 gene. There was statistically significant association between carbapenem resistant isolates and the presence of blaOXA-48 gene (P-value = 0.006).Wound swabs were the predominant clinical samples detected harboring bla OXA-48 gene both among the sensitive 5 (83.3%) and carbapenem resistant isolates 29(53.7) (P.value> 0.05).Our findings revealed high frequency of bla OXA-48 among carbapenem resistant isolates so identification of bla OXA-48 producing strains and taking efforts to reduce the rate of transferring these gene between the different strains is essential for optimization of therapy and improves of patients outcomes.

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Carbapenem Resistance Mechanisms in Pseudomonas aeruginosa Clinical Isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.2.480-484.2001 ◽

2001 ◽

Vol 45 (2) ◽

pp. 480-484 ◽

Cited By ~ 123

Author(s):

Hyunjoo Pai ◽

Jong-Won Kim ◽

Jungmin Kim ◽

Ji Hyang Lee ◽

Kang Won Choe ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Amino Acid ◽

Amino Acid Substitution ◽

Carbapenem Resistance ◽

Resistance Mechanisms ◽

Clinical Isolates ◽

Efflux System ◽

Clinical Strains ◽

Carbapenem Resistant

ABSTRACT In order to define the contributions of the mechanisms for carbapenem resistance in clinical strains of Pseudomonas aeruginosa, we investigated the presence of OprD, the expressions of the MexAB-OprM and MexEF-OprN systems, and the production of the β-lactamases for 44 clinical strains. All of the carbapenem-resistant isolates showed the loss of or decreased levels of OprD. Three strains overexpressed the MexAB-OprM efflux system by carrying mutations inmexR. These three strains had the amino acid substitution in MexR protein, Arg (CGG) → Gln (CAG), at the position of amino acid 70. None of the isolates, however, expressed the MexEF-OprN efflux system. For the characterization of β-lactamases, at least 13 isolates were the depressed mutants, and 12 strains produced secondary β-lactamases. Based on the above resistance mechanisms, the MICs of carbapenem for the isolates were analyzed. The MICs of carbapenem were mostly determined by the expression of OprD. The MICs of meropenem were two- to four-fold increased for the isolates which overexpressed MexAB-OprM in the background of OprD loss. However, the elevated MICs of meropenem for some individual isolates could not be explained. These findings suggested that other resistance mechanisms would play a role in meropenem resistance in clinical isolates of P. aeruginosa.

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Carbapenem resistance in non-fermentative bacterial species and in Enterobacteriaceae isolates from hospitalized patients in different health-care settings

Medicine and Pharmacy Reports ◽

10.15386/cjmed-282 ◽

2014 ◽

Vol 87 (4) ◽

pp. 235-241

Author(s):

Mihaela Ileana Ionescu ◽

Dan Stefan Neagoe ◽

Claudia Chiorean ◽

Loredana Dumitras ◽

Aurelia Rus

Keyword(s):

Health Care ◽

Pseudomonas Aeruginosa ◽

Intensive Care ◽

Intensive Care Units ◽

Carbapenem Resistance ◽

Hospitalized Patients ◽

Health Care Settings ◽

Carbapenem Resistant ◽

Acinetobacter Spp ◽

Resistant Strains

Aim. Carbapenem-resistant strains have been increasingly reported over the last few years. In this study we used laboratory records to determine the occurrence of carbapenem-resistant strains from hospitalized patients with emphasis on the comparative analysis of the incidence in various health-care settings. Materials and methods. From January 2012 to November 2012 and from May 2013 to November 2013, we evaluated 566 strains (Acinetobacter spp., Pseudomonas aeruginosa, Escherichia coli, and Klebsiella spp.). All isolates were tested and analyzed according to their antibiotic resistance phenotypic pattern. Laboratory results were correlated with data regarding admission in different clinical wards.Results. Among 566 isolates, 191 carbapenem-resistant or carbapenem-intermediate strains (33.74%) were detected. Non-fermentative species were the most prevalent carbapenem-resistant organisms, 80.62% of 191 carbapenem-resistant or carbapenem-intermediate strains isolated were Acinetobacter spp., and 17.27% of 191 were Pseudomonas aeruginosa. Apart from that, only 4 (2.09%) carbapenem-resistant Enterobacteriaceae (CRE) strains were identified. We identified 59.30% of 172 strains isolated from patients hospitalized in anesthesia and intensive care units non-susceptible to carbapenems. The main mechanism associated with carbapenem resistance could be the production of carbapenemase in combination with impermeability.Conclusions. Our study demonstrates that infections with carbapenem-resistant strains are correlated with hospitalization in intensive care units. Our data showed a predominant carbapenem-resistant Acinetobacter spp. strain in intensive care units.

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Prevalence of carbapenemase production in Pseudomonas aeruginosa isolates causing clinical infections in Lagos University Teaching Hospital, Nigeria

African Journal of Clinical and Experimental Microbiology ◽

10.4314/ajcem.v22i4.10 ◽

2021 ◽

Vol 22 (4) ◽

pp. 498-503

Author(s):

A.O. Ettu ◽

B.A. Oladapo ◽

O.O. Oduyebo

Keyword(s):

Pseudomonas Aeruginosa ◽

Teaching Hospital ◽

Dipicolinic Acid ◽

Phenylboronic Acid ◽

Carbapenem Resistance ◽

Clinical Isolates ◽

University Teaching ◽

Diffusion Method ◽

Carbapenem Resistant ◽

Mueller Hinton

Background: Pseudomonas aeruginosa has been highly associated with carbapenem resistance in which carbapenemases has been suggested to be a major contributory factor. Hence the objective of this study was to phenotypically detect KPC-type carbapenemase, metallo-β-lactamase and OXA-48 carbapenemase production in clinical isolates of P. aeruginosa in Lagos University Teaching Hospital (LUTH), NigeriaMethodology: One hundred and seventy-one P. aeruginosa isolates consecutively recovered from clinical specimens of patients with infections at the Medical Microbiology and Parasitology laboratory of the hospital were identified using MicrobactTM 24E kit. Preliminary screening for carbapenem resistance was determined by the disc diffusion method on Mueller-Hinton agar using single discs of meropenem and imipenem. Phenotypic detection of carbapenemase production among carbapenem-resistant isolates was performed by the combination disc test of meropenem-phenylboronic acid (MRPBO) and meropenem-dipicolinic acid (MRPDP) as recommended by EUCAST 2013 guideline. Results: Out of the 171 P. aeruginosa isolates, 35 (20.5%) were carbapenem non-susceptible (resistant) while carbapenemase production was detected in 27 (77.1%) of these carbapenem resistant isolates, and no enzyme was detected in 8 (22.9%). Of the 27 carbapenemase producing isolates, 22 (81.5%) produced MBL, 1 (3.7%) produced KPC, while 4 (14.8%) produced both KPC and MBL enzymes. Conclusion: This study revealed that carbapenem resistance among P. aeruginosa clinical isolates in our institution is gradually increasing. The mechanism for this rise is associated with carbapenemases, with MBL being the major carbapenemase involved. There is the need to ensure strict compliance with the LUTH infection control guidelines in order to check the rising incidence of infection caused by carbapenem resistant P. aeruginosa. French title: Prévalence de la production de carbapénémases dans les isolats de Pseudomonas aeruginosa causant des infections cliniques à l'hôpital universitaire de Lagos, Nigéria Contexte: Pseudomonas aeruginosa a été fortement associé à la résistance aux carbapénèmes dans laquelle les carbapénèmases ont été suggérées comme étant un facteur contributif majeur. Par conséquent, l'objectif de cette étude était de détecter phénotypiquement la production de carbapénémase de type KPC, de métallo-β-lactamase et de carbapénémase OXA-48 dans des isolats cliniques de P. aeruginosa au Lagos University Teaching Hospital (LUTH), Nigeria. Méthodologie: Cent soixante et onze isolats de P. aeruginosa récupérés consécutivement à partir d'échantillons cliniques de patients infectés au laboratoire de microbiologie médicale et de parasitologie de l'hôpital ont été identifiés à l'aide du kit MicrobactTM 24E. Le dépistage préliminaire de la résistance aux carbapénèmes a été déterminé par la méthode de diffusion sur disque sur gélose Mueller-Hinton en utilisant des disques uniques de méropénème et d'imipénème. La détection phénotypique de la production de carbapénèmes parmi les isolats résistants aux carbapénèmes a été réalisée par le test de disque combiné d'acide méropénème-phénylboronique (MRPBO) et d'acide méropénème-dipicolinique (MRPDP) tel que recommandé par la directive EUCAST 2013. Résultats: Sur les 171 isolats de P. aeruginosa, 35 (20,5%) étaient des carbapénèmes non sensibles (résistants) tandis que la production de carbapénèmes a été détectée dans 27 (77,1%) de ces isolats résistants aux carbapénèmes, et aucune enzyme n'a été détectée dans 8 (22,9%). Sur les 27 isolats producteurs de carbapénémases, 22 (81,5%) produisaient des MBL, 1 (3,7%) produisaient des KPC, tandis que 4 (14,8%) produisaient à la fois des enzymes KPC et MBL. Conclusion: Cette étude a révélé que la résistance aux carbapénèmes parmi les isolats cliniques de P. aeruginosa dans notre institution augmente progressivement. Le mécanisme de cette augmentation est associé aux carbapénémases, la MBL étant la principale carbapénémase impliquée. Il est nécessaire de garantir le strict respect des directives de contrôle des infections LUTH afin de contrôler l'incidence croissante des infections causées par P. aeruginosa résistant aux carbapénèmes.

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Interplay of Efflux System, ampC, and oprD Expression in Carbapenem Resistance of Pseudomonas aeruginosa Clinical Isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.50.5.1633-1641.2006 ◽

2006 ◽

Vol 50 (5) ◽

pp. 1633-1641 ◽

Cited By ~ 230

Author(s):

John Quale ◽

Simona Bratu ◽

Jyoti Gupta ◽

David Landman

Keyword(s):

Pseudomonas Aeruginosa ◽

Target Genes ◽

Stop Codon ◽

Premature Stop Codon ◽

Carbapenem Resistance ◽

Multidrug Resistant ◽

Clinical Isolates ◽

Carbapenem Resistant ◽

High Level ◽

Increased Activity

ABSTRACT Carbapenems are important agents for the therapy of infections due to multidrug-resistant Pseudomonas aeruginosa; the development of carbapenem resistance hampers effective therapeutic options. To assess the mechanisms leading to resistance, 33 clinical isolates with differing degrees of carbapenem susceptibility were analyzed for the expression of the chromosomal β-lactamase (ampC), the porin that is important for the entry of carbapenems (oprD), and the proteins involved in four efflux systems (mexA, mexC, mexE, and mexX). Real-time reverse transcriptase PCR was performed using primers and fluorescent probes for each of the target genes. The sequencing of regulatory genes (ampR, mexR, nalC, nalD, mexT, and mexZ) was also performed. Diminished expression of oprD was present in all imipenem- and meropenem-resistant isolates but was not required for ertapenem resistance. Increased expression of ampC was not observed in several isolates that were overtly resistant to carbapenems. Increased expression of several efflux systems was observed in many of the carbapenem-resistant isolates. Increased efflux activity correlated with high-level ertapenem resistance and reduced susceptibility to meropenem and aztreonam. Most isolates with increased expression of mexA had mutations affecting nalC and/or nalD. Two isolates with mutations leading to a premature stop codon in mexZ had markedly elevated mexX expressions, although mutations in mexZ were not a prerequisite for overexpression. β-Lactam resistance in clinical isolates of P. aeruginosa is a result of the interplay between diminished production of oprD, increased activity of ampC, and several efflux systems.

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Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp.

The Journal of Infection in Developing Countries ◽

10.3855/jidc.2924 ◽

2013 ◽

Vol 7 (11) ◽

pp. 880-887 ◽

Cited By ~ 15

Author(s):

Srujana Mohanty ◽

Vijeta Maurya ◽

Rajni Gaind ◽

Monorama Deb

Keyword(s):

Pseudomonas Aeruginosa ◽

Susceptibility Testing ◽

Carbapenem Resistance ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Phenotypic Characterization ◽

Antibiotic Susceptibility Testing ◽

Colistin Resistance ◽

Carbapenem Resistant ◽

Acinetobacter Spp

Introduction: Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P. aeruginosa and Acinetobacter spp. bloodstream isolates, phenotypically characterize the resistance mechanisms and evaluate the invitro activity of colistin. Methodology: Consecutive 145 (95 P.aeruginosa and 50 Acinetobacter spp.) non-repeat isolates were included. Antibiotic susceptibility testing was performed per CLSI guidelines. MIC for carbapenems and colistin was performed using Etest. Isolates showing reduced susceptibility or resistance to the carbapenems were tested for metallo-β-lactamase (MBL) production using imipenem-EDTA combined disk and MBL Etest. Results: Carbapenem resistance was observed in 40% P. aeruginosa and 66.0% Acinetobacter spp. Carbapenem-resistant (CA-R) isolates were significantly (p< 0.05) more frequently resistant to the other antibiotics than carbapenem-susceptible isolates. Approximately half of the CA-R strains were multidrug-resistant, and 3.1-5.5% were resistant to all antibiotics tested. MBL was found in 76.3% and 69.7% of the P. aeruginosa and Acinetobacter spp., respectively. Colistin resistance was observed in three (6.0%) Acinetobacter isolates and eight (8.4%) P. aeruginosa. MIC50 for carbapenems were two to four times higher for MBL-positive compared to MBL-negative isolates, but no difference was seen in MIC for colistin. Conclusion: Carbapenem resistance was observed to be mediated by MBL in a considerable number of isolates. Colistin is an alternative for infections caused by CA-R isolates; however, MIC testing should be performed whenever clinical use of colistin is considered.

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Coexistence of Metallo Beta Lactamase Resistant Gene Variants Among Clinical Isolates in Tertiary Care Hospital

Anti-Infective Agents ◽

10.2174/2211352518666200121144301 ◽

2021 ◽

Vol 18 (4) ◽

pp. 429-436

Author(s):

Santhiya K. ◽

Jayanthi S. ◽

Ananthasubramanian M. ◽

Appalaraju B.

Keyword(s):

Care Center ◽

Tertiary Care ◽

Medical Science ◽

Geographical Location ◽

Carbapenem Resistance ◽

Clinical Isolates ◽

Care Hospital ◽

Detection Rates ◽

Carbapenem Resistant ◽

Global Threat

Background: Carbapenem-resistant Enterobacteriaceae (CRE) has emerged as a global threat with mortality risk ranging from 48%-71% worldwide. The emergence of MBL resistance is threatening as carbapenem is one of the last line antibiotics. A total 24 variants of NDM resistance raises a concern to the clinicians and epidemiologists worldwide. Objective: The study aims at identifying MBL resistance (NDM, IMP, VIM, GIM, SPM, and SIM) and its coexistence in clinical isolates in a single tertiary care center. Methodology: Forty five clinical isolates characterized phenotypically for Carbapenem resistance obtained from PSG Institute of Medical Science and Research (PSG IMSR), Coimbatore, between February to March 2018 were taken for analysis. Result: Out of the 45 Clinical isolates, 38 isolates (84%) were detected as MBL carriers. VIM, NDM, GIM, and SPM were the predominant resistance genes, with detection rates of 48.8%, 28.8%, 24.4%, and 22.2% respectively. Fifteen isolates were observed to harbor more than one MBL gene in coexistence. Two isolates - U42 and R714 (K. pneumoniae) were found to harbor all 5 MBL variants in combination. Conclusion: 33% of clinical isolates harboring multiple MBL variants is a concern in clinical settings. The presence of SPM and GIM gene amongst isolates in this geographical location within India is an indicator demanding continuous monitoring of these resistance determinants.

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Prevalence of metallo-β-lactamase genes among Pseudomonas aeruginosa isolated from various clinical samples in China

Journal of Laboratory Medicine ◽

10.1515/labmed-2019-0162 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Wei Wang ◽

Xiaoya Wang

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Susceptibility ◽

Ethylenediaminetetraacetic Acid ◽

Carbapenem Resistance ◽

Opportunistic Pathogen ◽

Detection Methods ◽

Clinical Samples ◽

Routine Practice ◽

Carbapenem Resistant ◽

High Prevalence

AbstractBackgroundPseudomonas aeruginosa is an opportunistic pathogen which is associated with nosocomial infections and causes various diseases including urinary tract infection, pneumonia, soft-tissue infection and sepsis. The emergence of P. aeruginosa-acquired metallo-β-lactamase (MBL) is most worrisome and poses a serious threat during treatment and infection control. The objective of this study was to identify antibiotic susceptibility, phenotypic detection of MBL production and to determine the prevalence of MBL genes in carbapenem-resistant P. aeruginosa isolated from different clinical samples.MethodsA total of 329 non-duplicate P. aeruginosa isolated from various clinical samples from two hospitals in China between September 2017 and March 2019 were included in this study. Phenotypic detection of MBL was performed by the combined detection method using imipenem and imipenem-ethylenediaminetetraacetic acid (EDTA) discs. MBL-encoding genes including blaVIM-1, blaVIM-2, blaIMP-1, blaIMP-2, blaSPM-1, blaSIM, blaNDM-1 and blaGIM were detected by polymerase chain reaction (PCR).ResultsOf the 329 P. aeruginosa, majority of the isolates were resistant to imipenem (77.5%) followed by meropenem (64.7%). Of the 270 P. aeruginosa isolates tested, 149 (55.2%) isolates were found to be positive for MBL detection. Of the different samples, 57.8% (n = 26) of P. aeruginosa isolated from blood were found to be positive for MBL production. Of the various MBL genes, blaIMP-1 (28.2%) was the most predominant gene detected followed by blaVIM-2 (18.8%), blaVIM-1 (16.1%), blaNDM-1 (9.4%), blaIMP-2 (6.7%), blaSIM (6.0%), blaSPM-1 (4.0%) and blaGIM (1.3%) genes.ConclusionsThe high resistance of P. aeruginosa toward imipenem and meropenem and the high prevalence of blaIMP-1 and blaVIM-2 set the alarm on the increasing, perhaps the increased, carbapenem resistance. In addition to routine antibiotic susceptibility testings, our results emphasize the importance of both the phenotypic and genotypic MBL detection methods in routine practice for early detection of carbapenem resistance and to prevent further dissemination of this resistant pathogen.

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