Molecular epidemiology and carbapenem resistance of Pseudomonas aeruginosa isolated from patients with burns

2021 ◽  
Vol 30 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Younes Khalili ◽  
Mohammad Yousef Memar ◽  
Safar Farajnia ◽  
Khosro Adibkia ◽  
Hossein Samadi Kafil ◽  
...  

Objective: The aim of this study was to investigate the molecular epidemiology and carbapenem resistance mechanisms of Pseudomonas aeruginosa isolated from patients with burns in Azerbaijan, Iran. Method: Pseudomonas aeruginosa was isolated from 38 patients with burns. Disk diffusion and agar dilution methods were used to determine antibiotic susceptibility patterns. The overproduction of AmpC β-lactamase and efflux pumps were detected by phenotypic methods. The presence of carbapenemase-encoding genes was detected by multiplex polymerase chain reaction (PCR). Expression of the OprD gene and MexAB efflux pumps were also evaluated with real-time PCR. Random amplified polymorphic DNA typing (RAPD-PCR) was used for genotyping of carbapenem-resistant Pseudomonas aeruginosa (CRPA). Results: Minimum inhibitory concentration (MIC) assays demonstrated high levels of resistance to all classes of antibiotics except colistin and polymyxin B. The initial screening by carbapenem disks indicated 24 isolates (63.15%) as CRPA. Different mechanisms of carbapenem resistance were observed, including carbapenemase production (8.4%), overexpression of AmpC (25%) and decreased expression of OprD (75%). The overexpression of MexAB efflux pumps was detected in 19 (79.1%) isolates by phenotypic assay or real-time PCR. The resistance to carbapenem was multifactorial in most cases (58.3%). The RAPD genotyping revealed different patterns with nine clusters. Conclusion: According to our results, the prevalence of CRPA is at an alarming level. Our results did not demonstrate an epidemic clone. The most common mechanism of carbapenem resistance was decreased expression of OprD. Therefore, we suggest a reconsideration in the management of CRPA infections of patients in our burn care hospital in Azerbaijan, Iran.

2021 ◽  
Vol 10 (02) ◽  
pp. 89-93
Author(s):  
Shaista Bakhat ◽  
Yasmeen Taj ◽  
Faisal Hanif ◽  
Saman Nadeem

Objective: To determine the prevalence of carbapenem resistance in strains of Pseudomonas aeruginosa at a molecular level by detecting OXA-48 gene which transcribe for resistance to the antibiotic carbapenem among indoor patients of a tertiary care hospital Karachi. Study Design and Setting: This observational cross-sectional study was conducted from September 2018 to May 2019 at PNS Shifa hospital of Karachi. Methodology: Total 140 strains of Pseudomonas aeruginosa were received and cultured from pus samples. These samples were collected from different wards like medicine, surgery, burn unit, ICU, ENT, plastic surgery, paedriatic and family ward. Carbapenem resistance was screened phenotypically by AST (Antibiotic susceptibility test), MHT (Modified Hodge test) and mCIM (Modified Carbapenem Inactivation Method) in all samples. Only in resistant cases OXA-48 gene was detected by real time PCR (polymerase chain reaction). Data was analyzed by following the proper loading sequence on product specification sheet. Data was statistically analyzed by SPSS version 23.0. Results were expressed as frequencies (percentages). Results: Out of 140, 17 (12%) were found to be resistant to carbapenem by AST, 20 (14%) by MHT, 25 (17.8%) by mCIM. Out of 25 resistant cases, 4 (16%) presence of OXA-48 gene by real time PCR were detected. Conclusion: OXA-48 gene showed 16% carbapenem resistance in this study. Pseudomonas aeruginosa is an opportunistic organism which causes multidrug resistance especially in hospitalized patients. Carbapenem is the last resort for serious infections


2018 ◽  
Vol 11 (12) ◽  
pp. 935-943 ◽  
Author(s):  
Mona Shaaban ◽  
Ahmed Al-Qahtani ◽  
Mohammed Al-Ahdal ◽  
Rasha Barwa

Introduction: Emergence of carbapenem resistance in Pseudomonas aeruginosa increases the therapeutic dilemma. In this study, we investigated various mechanisms involved in the resistance of P. aeruginosa clinical isolates to carbapenems. Methodology: P. aeruginosa isolates were isolated from different clinical samples. The antimicrobial susceptibility was evaluated by disc diffusion method. Carbapenemases were detected among carbapenem resistant isolates. Expression level of mexB and oprD was determined by real-time PCR. Molecular relatedness among isolates was detected based on pulse-field gel electrophoresis (PFGE). Results: Ninety P. aeruginosa isolates were purified from clinical specimens. High levels of resistance to imipenem and meropenem were detected in 16 isolates. PCR analysis of carbapenemases indicated the prevalence of Verona integron-encoded metallo-beta-lactamase (VIM); four isolates produced only VIM enzymes (VIM-1 or VIM-2), while the remaining twelve co-produced both VIM-1 or VIM-2 and NDM enzymes. Additionally, real-time PCR analysis elucidated high expression levels of mexB in seven of the carbapenem resistant isolates and low expression of oprD in seven isolates. The identified carbapenem-resistant isolates were clustered into eleven PFGE profiles where clusters E1 and E2 involved isolates exhibiting multiple carbapenemase genes (blaNDM-1, blaVIM-1 and blaVIM-2). Conclusion: Various mechanisms underlying carbapenem resistance have been detected in our P. aeruginosa cohort of isolates. Emergence of P. aeruginosa as a reservoir of multiple carbapenemases is increasing over time limiting the treatment options to this serious infection. This increases the urgency for infection control practices to reduce the incidence of this infection.


2010 ◽  
Vol 35 (5) ◽  
pp. 486-491 ◽  
Author(s):  
Jie Wang ◽  
Jian-ying Zhou ◽  
Ting-ting Qu ◽  
Ping Shen ◽  
Ze-qing Wei ◽  
...  

2005 ◽  
Vol 71 (11) ◽  
pp. 6823-6830 ◽  
Author(s):  
P. Martorell ◽  
A. Querol ◽  
M. T. Fernández-Espinar

ABSTRACT Despite the beneficial role of Saccharomyces cerevisiae in the food industry for food and beverage production, it is able to cause spoilage in wines. We have developed a real-time PCR method to directly detect and quantify this yeast species in wine samples to provide winemakers with a rapid and sensitive method to detect and prevent wine spoilage. Specific primers were designed for S. cerevisiae using the sequence information obtained from a cloned random amplified polymorphic DNA band that differentiated S. cerevisiae from its sibling species Saccharomyces bayanus, Saccharomyces pastorianus, and Saccharomyces paradoxus. The specificity of the primers was demonstrated for typical wine spoilage yeast species. The method was useful for estimating the level of S. cerevisiae directly in sweet wines and red wines without preenrichment when yeast is present in concentrations as low as 3.8 and 5 CFU per ml. This detection limit is in the same order as that obtained from glucose-peptone-yeast growth medium (GPY). Moreover, it was possible to quantify S. cerevisiae in artificially contaminated samples accurately. Limits for accurate quantification in wine were established, from 3.8 × 105 to 3.8 CFU/ml in sweet wine and from 5 × 106 to 50 CFU/ml in red wine.


2011 ◽  
Vol 55 (12) ◽  
pp. 5597-5601 ◽  
Author(s):  
Paul P. Cook ◽  
Michael Gooch ◽  
Shemra Rizzo

ABSTRACTWe examined the effect of the addition of ertapenem to our hospital formulary on the resistance of nosocomialPseudomonas aeruginosato group 2 carbapenems (imipenem, meropenem, and doripenem). This was a retrospective, observational study conducted between 1 January 2000 and 31 January 2009 at a large, tertiary-care hospital. Autoregressive integrated moving average (ARIMA) regression models were used to evaluate the effect of ertapenem use on the susceptibility ofPseudomonas aeruginosato group 2 carbapenems as well as on the use of the group 2 carbapenems, ciprofloxacin, and other antipseudomonal drugs (i.e., tobramycin, cefepime, and piperacillin-tazobactam). Resistance was expressed as a percentage of total isolates as well as the number of carbapenem-resistant bacterial isolates per 10,000 patient days. Pearson correlation was used to assess the relationship between antibiotic use and carbapenem resistance. Following the addition of ertapenem to the formulary, there was a statistically significant decrease in the percentage ofPseudomonas aeruginosaisolates resistant to the group 2 carbapenems (P= 0.003). Group 2 carbapenem use and the number of carbapenem-resistantPseudomonas aeruginosaisolates per 10,000 patient days did not change significantly over the time period. There was a large decrease in the use of ciprofloxacin (P= 0.0033), and there was a correlation of ciprofloxacin use with the percentage of isolates resistant to the group 2 carbapenems (ρ = 0.47,P= 0.002). We suspect that the improvement in susceptibility ofPseudomonas aeruginosato group 2 carbapenems was related to a decrease in ciprofloxacin use.


2009 ◽  
Vol 53 (11) ◽  
pp. 4783-4788 ◽  
Author(s):  
José-Manuel Rodríguez-Martínez ◽  
Laurent Poirel ◽  
Patrice Nordmann

ABSTRACT The contributions of different mechanisms of resistance to carbapenems among a collection of imipenem- and meropenem-nonsusceptible Pseudomonas aeruginosa isolates were investigated. This screening included the recently reported extended-spectrum cephalosporinases (ESACs) weakly hydrolyzing carbapenems. Eighty-seven percent of the studied isolates were resistant to imipenem. Genes encoding metallo-β-lactamases or carbapenem-hydrolyzing oxacillinases were not identified. The main mechanism associated with imipenem resistance was the loss of outer membrane protein OprD. Identification of overexpressed ESACs and loss of OprD were observed for 65% of the isolates, all being fully resistant to imipenem. Resistance to meropenem was observed in 78% of the isolates, with all but one also being resistant to imipenem. Overexpression of the MexAB-OprM, MexXY-OprM, or MexCD-OprJ efflux systems was observed in 60% of the isolates, suggesting the contribution of efflux mechanisms in resistance to meropenem. The loss of porin OprD and the overproduction of ESACs were observed in 100% and 92% of the meropenem-resistant isolates, respectively. P. aeruginosa can very often accumulate different resistance mechanisms, including ESAC production, leading to carbapenem resistance.


2020 ◽  
Vol 56 (4) ◽  
pp. 2000769 ◽  
Author(s):  
Martina Oriano ◽  
Andrea Gramegna ◽  
Leonardo Terranova ◽  
Giovanni Sotgiu ◽  
Imran Sulaiman ◽  
...  

IntroductionNeutrophilic inflammation is a major driver of bronchiectasis pathophysiology, and neutrophil elastase activity is the most promising biomarker evaluated in sputum to date. How active neutrophil elastase correlates with the lung microbiome in bronchiectasis is still unexplored. We aimed to understand whether active neutrophil elastase is associated with low microbial diversity and distinct microbiome characteristics.MethodsAn observational, cross-sectional study was conducted at the bronchiectasis programme of the Policlinico Hospital in Milan, Italy, where adults with bronchiectasis were enrolled between March 2017 and March 2019. Active neutrophil elastase was measured on sputum collected during stable state, microbiota analysed through 16S rRNA gene sequencing, molecular assessment of respiratory pathogens carried out through real-time PCR and clinical data collected.ResultsAmong 185 patients enrolled, decreasing α-diversity, evaluated through the Shannon entropy (ρ −0.37, p<0.00001) and Pielou's evenness (ρ −0.36, p<0.00001) and richness (ρ −0.33, p<0.00001), was significantly correlated with increasing elastase. A significant difference in median levels of Shannon entropy as detected between patients with neutrophil elastase ≥20 µg·mL−1 (median 3.82, interquartile range 2.20–4.96) versus neutrophil elastase <20 µg·mL−1 (4.88, 3.68–5.80; p<0.0001). A distinct microbiome was found in these two groups, mainly characterised by enrichment with Pseudomonas in the high-elastase group and with Streptococcus in the low-elastase group. Further confirmation of the association of Pseudomonas aeruginosa with elevated active neutrophil elastase was found based on standard culture and targeted real-time PCR.ConclusionsHigh levels of active neutrophil elastase are associated to low microbiome diversity and specifically to P. aeruginosa infection.


MedPharmRes ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 18-22
Author(s):  
Mai Thi Thanh Nguyen ◽  
Chuong Van Le ◽  
Phuong Mai Doan ◽  
Chinh Van Nguyen ◽  
Huy Quang Vu

Introduction: The production of carbapenem enzyme is one of the most frequent mechanisms reported in cabapenem resistant Pseudomonas aeruginosa. Besides, a growing number of mobile colistin resistance (MCR) genes are threatening the renewed interest of colistin as a "last-resort" against carbapenem-resistant pathogens. Therefore, the detection of carbapenem-resistant and colistin-resistant phenotypes as well as preventing transmission of multi-resistant P. aeruginosa strains with genes coding for carbapenemase is extremely necessary. Material and methods: Among 159 P. aeruginosa strains were collected 46 isolates, which is resistant or intermediated to meropenem. Modified carbapenem inactivation (mCIM) and colistin broth disk elution (CBDE) methods were used to identify carbapenemase-producing strains and colistin resistance. In addition, a multiplex real-time PCR technique was applied to investigate the frequency of emergence of carbapenem resistance genes. Results: The results revealed that 25 strains (54.3%) were positive with mCIM test and none of them resistant to colistin by CBDE method. Number of strains carrying a gene blaIMP: 4 strains (16%), blaNDM: 2 strains (8%). Strains are carrying two genes: blaIMP + blaNDM: 10 strains (40%), blaVIM + blaNDM: 1 strain (4%), blaNDM + blaOXA-48: 1 strain (4%) and are carrying three genes blaIMP + blaNDM + blaOXA-48: 6 strains (24%), blaKPC + blaIMP + blaNDM: 1 strain (4%). Conclusions: All mCIM positive P. aeruginosa were contained carbapenemase genes. Colistin still reserved a good effect to combine with other antibiotics in multi-resistant treatment. Hence, the classification of genes can help clinicians selected appropriate antibiotics so that more effective treatment for patients.


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