scholarly journals Phenotypic and genotypic characterization of carbapenem-resistant Acinetobacter baumannii isolates from Egypt

Author(s):  
Alaa Abouelfetouh ◽  
Aisha S. Torky ◽  
Elsayed Aboulmagd

Abstract Background Antibiotic use is largely under-regulated in Egypt leading to the emergence of resistant isolates. Carbapenems are last resort agents to treat Acinetobacter baumannii infections resistant to other classes of antibiotics. However, carbapenem-resistant isolates are emerging at an alarming rate. This study aimed at phenotypically and molecularly characterizing seventy four carbapenem-unsusceptible A. baumannii isolates from Egypt to detect the different enzymes responsible for carbapenem resistance. Methods Carbapenemase production was assessed by a number of phenotypic methods: modified Hodge test (MHT), carbapenem inactivation method (CIM), combined disc test (CDT), CarbAcineto NP test and boronic acid disc test. Polymerase chain reaction (PCR) was used to screen the isolates for the presence of some genes responsible for resistance to carbapenems, as well as some insertion sequences. Results PCR amplification of class D carbapenemases revealed the prevalence of blaOXA-51 and blaOXA-23 in 100% of the isolates and of blaOXA-58 in only one isolate (1.4%). blaVIM and blaNDM-1 belonging to class B metallo-β-lactamases were present in 100 and 12.1% of the isolates, respectively. The prevalence of ISAba1, ISAba2 and ISAba3 was 100, 2.7 and 4.1%, respectively. None of the tested isolates carried blaOXA-40, blaIMP, blaSIM, blaSPM, blaGIM or the class A blaKPC. Taking PCR as the gold standard method for the detection of different carbapenemases, the sensitivities of the MHT, CIM, CDT, CarbAcineto NP test and boronic acid disc/imipenem or meropenem test for this particular collection of isolates were 78.4, 68.9, 79.7, 95.9, and 56.8% or 70.3%, respectively. Conclusions The widespread detection of carbapenem-resistant A. baumannii (CR-AB) has become a real threat to the efficacy of treatment regimens. Among the studied cohort of CR-AB clinical isolates, blaOXA-51, blaOXA-23 and blaVIM were the most prevalent, followed by blaNDM-1 and blaOXA-58. The genotypic detection of carbapenemases among CR-AB clinical isolates using PCR was most conclusive, followed closely by the phenotypic testing using CarbAcineto NP test.

2020 ◽  
Author(s):  
Reem M Hassan ◽  
Sherifa T Salem ◽  
Saly Ismail Mostafa Hassan ◽  
Asmaa Sayed Hegab ◽  
Yasmine S Elkholy

AbstractAcinetobacter baumannii (A. baumannii) represents a global threat owing to its ability to resist most of the currently available antimicrobial agents. Moreover, emergence of carbapenem resistant A. baumannii (CR-AB) isolates limits the available treatment options. Enzymatic degradation by variety of ß-lactamases, have been identified as the most common mechanism of carbapenem resistance in A. baumannii. The alarming increase in the prevalence of CR-AB necessitates continuous screening and molecular characterization to appreciate the problem. The present study was performed to assess the prevalence and characterize carbapenemases among 206 CR-AB isolated from various clinical specimens collected from different intensive care units at Kasr Al-Aini Hospital.All isolates were confirmed to be A. baumannii by detection of the blaOXA-51-like gene. Molecular screening of 13 common Ambler class bla carbapenemases genes in addition to insertion sequence (IS-1) upstream OXA-23 was performed by using four sets of multiplex PCR, followed by identification using gene sequencing technology. Among the investigated genes, the prevalence of blaOXA-23, and blaOXA-58 were 77.7%, and 1.9%, respectively. The ISAba1 was detected in 10% of the blaOXA-23 positive isolates. The prevalence of metallo-β-lactamases (MBLs) studied; blaNDM-1, blaSPM, blaVIM, blaSIM-1 were 11.7%, 6.3%, 0.5%, and 0.5% respectively. One of class A; bla KPC was detected in 10.7% of the investigated isolates. blaOXA-24/40, blaIMP, blaGES, blaVEB and blaGIM were not detected in any of the studied isolates. Moreover, 18.4% of the isolates have shown to harbor two or more of the screened bla genes. We concluded that the most prevalent type of ß-lactamases genes among CR-AB isolates collected from Egyptian patients were blaOXA-23 followed by blaNDM-1 and blaKPC.Author summaryCarbapenem-resistant A. baumannii has become a real global health threat. The aim of the present study was to characterize and to assess the prevalence of carbapenemases among 206 CR-AB clinical isolates from Egyptian patients. We concluded that the most prevalent type of ß-lactamases genes among CR-AB isolates collected from Egyptian patients were blaOXA-23 followed by blaNDM-1 and blaKPC. In this study, ISAba1 was detected upstream 10% of blaOXA-23 positive isolates only which indicates that the spread of resistance among Acinetobacter isolates could be either chromosomal or plamid-mediated.


2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Nureen Zahra ◽  
Basit Zeshan ◽  
Muhammad Mubeen Ali Qadri ◽  
Musarat Ishaq ◽  
Muhammad Afzal ◽  
...  

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a significant nosocomial pathogen, causing serious threats concerning community-wide outbreaks globally, as well as in Pakistan. Antimicrobial resistance in A. baumannii is increasing day by day. Objectives: The study aimed to find out the antibiotic resistance (AMR) patterns and evaluate the AMR genes in clinical isolates from patients admitted to the surgical Intensive Care units (ICUs) at different hospitals in Lahore, Pakistan. Methods: A total of 593 clinical specimens were collected from patients admitted to the surgical ICUs of three different local hospitals in Lahore, Pakistan. From these samples, a total of 90 A. baumannii isolates were identified and further investigated to observe phenotypic resistance patterns and detect carbapenemases resistance genes. Results: The results showed that phenotypic resistance against amikacin was 27.2%, ceftriaxone 100%, ceftazidime 27.2%, cefepime 63.3%, ciprofloxacin and co-trimoxazole 100%, gentamicin 40%, imipenem 22.2%, meropenem 21.1%, piperacillin-tazobactam 27.2%, tigecycline 27.2%, and tetracycline 63.3%. All A. baumannii isolates were found to be sensitive to colistin (CT), polymixin-B (PB), and tobramycin (TOB). The PCR amplification of carbapenemases genes revealed the prevalence of blaOXA-23, blaOXA-51, and blaOXA-40 in 73, 90, and 64.4% of the isolates, respectively, along with blaNDM1 (92.2%), blaVIM (40%), blaIMP (90%), ISAba1 (85.5%), sul1 (16.6%), sul2 (20%), armA (32.2%), and PER-1 (12%) while the blaOXA-24 and blaOXA-58 genes were not detected in the isolates. The sequence analysis of the blaOXA-23 and blaOXA-51 genes showed 98% and 95% similarity with previously reported sequences in the GenBank database. Conclusions: The present study indicated that the emergence of high carbapenem resistance in CRAB isolates has increased, which may pose serious limitations in the choice of drugs for nosocomial infections.


Author(s):  
Abolfazl Vahhabi ◽  
Alka Hasani ◽  
Mohammad Ahangarzadeh Rezaee ◽  
Behzad Baradaran ◽  
Akbar Hasani ◽  
...  

Background and Objectives: Carbapenem treatment for Acinetobacter baumannii infections presently faces threats owing to the production of several types of carbapenemase enzymes, prevalence of which varies among different countries. We explored the current trend of antibiotic resistance in A. baumannii clinical isolates from North West Iran, sought the mechanism of carbapenem resistance and addressed the sequence type groups in carbapenem resistant A. baumannii (CRAB). Materials and Methods: A. baumannii (n=112) isolates were recovered from various clinical specimens of patients admitted in internal, surgery, burn, infectious diseases and various ICUs wards. Genetically confirmed A. baumannii isolates were screened for carbapenem resistance by the Kirby-Bauer and E-test and the presence of bla PCR. Sequence groups were identified by multiplex PCR. Results: Multidrug-resistance (MDR) was a characteristic feature of all A. baumannii isolates. Frequency of oxacillinase genes in combination including blaOXA-51-like/blaOXA-23-like, blaOXA-51-like OXA-24/40-like and blaOXA-51-like/blaOXA-23-like/blaOXA-24/40-like was 82.1%, 36.6% and 25.8% respectively. Blending of oxacillinase and MBL genes was evident in eight bla positive and 7 blaOXA-24-like positive isolates thereby depicting synchronous etiology of carbapenem resistance. Amongst CRAB isolates, 97.3% contained ISAba1 element and 50.9% belonged to the European clone II. Conclusion: Synchronicity among blaOXA-like with bla and ISAba1 gene was a hallmark of this investigation. Though origin or route of transmission was not elucidated in this study but co-existence among OXA and MBL producing genes is a therapeutic concern demanding strict surveillance strategies and control programs to halt the dissemination of these isolates in the hospital setting.


Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 864
Author(s):  
Krit Thirapanmethee ◽  
Thayapa Srisiri-a-nun ◽  
Jantana Houngsaitong ◽  
Preecha Montakantikul ◽  
Piyatip Khuntayaporn ◽  
...  

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical health concern for the treatment of infectious diseases. The aim of this study was to investigate the molecular epidemiology of CRAB emphasizing the presence of oxacillinase (OXA)-type β-lactamase-encoding genes, one of the most important carbapenem resistance mechanisms. In this study, a total of 183 non-repetitive CRAB isolates collected from 11 tertiary care hospitals across Thailand were investigated. As a result, the blaoxa-51-like gene, an intrinsic enzyme marker, was detected in all clinical isolates. The blaoxa-23-like gene was presented in the majority of isolates (68.31%). In contrast, the prevalence rates of blaoxa-40/24-like and blaoxa-58-like gene occurrences in CRAB isolates were only 4.92% and 1.09%, respectively. All isolates were resistant to carbapenems, with 100% resistance to imipenem, followed by meropenem (98.91%) and doripenem (94.54%). Most isolates showed high resistance rates to ciprofloxacin (97.81%), ceftazidime (96.72%), gentamicin (91.26%), and amikacin (80.87%). Interestingly, colistin was found to be a potential drug of choice due to the high susceptibility of the tested isolates to this antimicrobial (87.98%). Most CRAB isolates in Thailand were of ST2 lineage, but some belonged to ST25, ST98, ST129, ST164, ST215, ST338, and ST745. Further studies to monitor the spread of carbapenem-resistant OXA-type β-lactamase genes from A. baumannii in hospital settings are warranted.


Author(s):  
Rabia Arshad

Background: Antimicrobial resistance is one of the research priorities of health organizations due to increased risk of morbidity and mortality. Outbreaks of nosocomial infections caused by carbapenem-resistant Acinetobacter Baumannii (CRAB) strains are at rise worldwide. Antimicrobial resistance to carbapenems reduces clinical therapeutic choices and frequently led to treatment failure. The aim of our study was to determine the prevalence of carbapenem resistance in A. baumannii isolated from patients in intensive care units (ICUs). Methods: This cross-sectional study was carried out in the Department of Microbiology, Basic Medical Sciences Institute (BMSI), Jinnah Postgraduate Medical Centre (JPMC), Karachi, from December 2016 to November 2017. Total 63 non-repetitive A. baumannii were collected from the patients’ specimens, admitted to medical and surgical ICUs and wards of JPMC, Karachi. The bacterial isolates were processed according to standard microbiological procedures to observe for carbapenem resistance. SPSS 21 was used for data analysis. Results: Out of the 63 patients, 40 (63.5%) were male. The age of the patient ranged from 15-85 year, with average of 43 year. 34.9% patients had been hospitalized for 3 days. Chronic obstructive pulmonary disease was present in highest number with average of 58.7% for morbidity. Number of patients on mechanical ventilation was highest (65.1%). All isolates were susceptible to colistin. The resistance to ampicillin-sulbactam, ceftazidime, ciprofloxacin, amikacin, piperacillin- tazobactam and meropenem was 82.5%, 81%, 100%, 87.3%, 82.5% and 82% respectively. Out of 82% CRAB, 77% were obtained from ICUs. Conclusion: This study has revealed the high rate of carbapenem resistance in A. baumannii isolates in ICUs thus leaving behind limited therapeutic options.


2021 ◽  
Vol 18 (4) ◽  
pp. 429-436
Author(s):  
Santhiya K. ◽  
Jayanthi S. ◽  
Ananthasubramanian M. ◽  
Appalaraju B.

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.


2021 ◽  
Vol 71 (11) ◽  
pp. 2576-2581
Author(s):  
Saima Ishtiaq ◽  
Sidrah Saleem ◽  
Abdul Waheed ◽  
Arslan Ahmed Alvi

Objective: To evaluate carbapenem resistance and to detect blaOXA-23 and blaOXA-51 genes in carbapenem-resistant acinetobacter baumanii isolates recovered from patients having pneumonia secondry to ventilation. Methods: The cross-sectional study was conducted from July 2017 to June 2018 at the Department of Microbiology, University of Health Sciences, Lahore, Pakistan, and comprised endotracheal aspirates / tracheobroncheal lavage samples from patients irrespective of age and gender who developed pneumonia after being on the ventilator for 48 hrs at the Combined Military Hospital, and Jinnah Hospital, Lahore.  The samples were inoculated on MacConkey and blood agar and aerobically incubated at a temperature of 370C for 18-24 hours. The isolated organisms were further assessed by standard morphological, cultural and biochemical profile. Antibiotic susceptibility was done by Kirby-Bauer disc diffusion method. Carbapenem-resistant acinetobacter baumannii were checked for carbapenemase production using Modified Hodge Test. Conventional polymerase chain reaction and agarose gel electrophoreses were performed to detect blaOXA-23 and blaOXA-51 genes. Data was analysed using SPSS 17. Results: Out of 157 samples, 92(58.6%) yielded growth of bacteria, and, among them, 39(42.4%) were identified as acinetobacter baumannii. All (100%) acinetobacter baumannii cases showed resistance to carbapenem, were producing carbapenemase enzyme, and were positive for blaOXA-51 gene. The blaOXA-23 gene was amplified in 38(97.4%) isolates. Conclusion: BlaOXA-23 gene appeared to be the major cause of carbapenem resistance. Continuous...


2021 ◽  
Author(s):  
Namrata Kumari ◽  
Mukesh Kumar ◽  
Amit Katiyar ◽  
Abhay Kumar ◽  
Pallavi Priya ◽  
...  

Abstract Carbapenemase-producing clinical isolates are becoming more common over the world, posing a severe public health danger, particularly in developing nations like India. Carbapenem-resistant Gram-negative bacterial (CR-GNB) infection has become a fast-expending global threat with limited antibiotic choice and significant mortality. The aim of this study was to highlight the carbapenem-resistance among clinical isolates of hospital admitted patients in Bihar, India. A cross-sectional study was conducted with 101 clinical isolates of E. coli, K. pneumoniae, A. baumannii, and P. aeruginosa. All GNB isolates were tested for their antimicrobial susceptibility using double disc synergy test / modified hodge test (DDST/MHT) and subsequently confirmed carbapenemase-producing isolates were evaluated for carbapenem-resistance genes using whole-genome sequencing (genotypically) method. The overall percentage of carbapenem-resistance among GNB was (17/101) 16.83%. The AMR analysis demonstrates a significantly high prevalence of blaCTX−M followed by blaSHV, blaTEM, blaOXA and blaNDM β-lactams carbapenem-resistance genes among clinical isolates of GNB. Co-occurrence of carbapenemase-encoding genes with blaNDM was found in 70.6% of carbapenemase-producing isolates. Our study highlights the mechanism of carbapenem-resistance to curb the overwhelming threat posed by emergence of drug-resistance in India.


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