Showing 8 results for Beta-Lactamase
Jahani, S, Shahreki Zahedani, Sh, Karbasizade, V,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: In the past, most strains of E. coli were susceptible to a wide range of antimicrobial agents, but this situation is now changed by indiscriminate use of antibiotics. Ceftriaxone and Ceftazidime are the most current antibiotics used for Enterobacteriaceae infections in hospitals. The aim of this study was to determine antimicrobial resistance of Escherichia coli strains isolated from patients. Material and Methods: During a 12-month period, 200 clinical samples taken from patients referred to Zahedan hospitals were assessed to isolate Escherichia coli. Antibiotic susceptibility was determined by disk diffusion method and micro-broth dilution and Bla TEM resistance genes were detected by PCR. Results: Following phenotype verification testing, 112 isolates (56%) were produced Extended Spectrum Beta Lactamase (ESBLs) and 130 isolates were potential producers of beta-lactamase (ESBL). Using PCR, 72 isolates (38.55%) have TEM gene. Conclusion: The rate of antibiotic resistance of Escherichia coli isolates to ceftriaxone and ceftazidime is high therefore, it seems reasonable to do antibiogram before treatment. Keywords: Extended-Spectrum-Beta-Lactamase, Esherchia coli, Disc Diffusin, Micro-Broth Dilution
Shahraki, Sh, Bokaeian, M, Rigi, Sh,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: Klebsiella pneumoniae is an opportunistic nosocomial pathogen causing a variety of infections including urinary tract infections, pneumonia, septicemia, wound infections and infections in the intensive care units. Since the ESBL producing Klebsiella pneumoniae strains are increasingly causing urinary tract infections, we aim to assess antibiotic resistance pattern and evaluate the prevalence of ESBL in Klebsiella pneumoniae isolated from urinary tract infections. Material and Methods: this cross-sectional study was conducted on 122 Klebsiella pneumoniae strains collected from Zahedan hospitals. After final identification of isolates, antibiotic susceptibility tests were carried out by using disk diffusion in agar method for 16 antibiotics and ESBL production was determined by the combined disk method. Results: The Klebsiella pneumoniae strains showed susceptibility to imipenem and amikacin ( 94.3%) ,chloramphenicol (88.5%) , gentamicin (81.1%) , ciprofloxacin (80.3%) , cefepime (73%) ,streptomycin (72.1%), nalidixic acid (68%) , tetracycline (65.6%), and cefotaxime, ceftazidime, cefpodoxime (62.3%) . The resistance of strains was seen to nitrofurantoin (53.3%), cotrimoxazole (39.3%), Cefpodoxime (37.7%), cefotaxime (36.9%), ceftriaxone (36.1%), aztreonam (34.4%), ceftazidime (32.8%). Thirty-eight isolates (31.1%) were shown to produce ESBLs. Conclusion: A high rate of resistance was observed to most of the antibiotics among ESBL producing strains therefore, it is important to be careful about the use of antibiotics and identification of ESBL using phenotypic methods. Keywords: Antibiotic Resistance, Extended Spectrum Beta-Lactamases,KlebsiellaPneumoniae, Urinary Tract Infection, Isolate
J Vazirzadeh, H Ghajavand , L Heidari , P Behshood ,
Volume 9, Issue 3 (9-2015)
Abstract
Abstract
Background and Objective: Acinetobacter species are opportunistic important pathogens responsible for many nosocomial infections. The purpose of this study was to determine the drug resistan pattern Acinetobacter baumannii and prevalence of ESBL producing strains in Intensive Care Unit patients in Isfahan city hospitals.
Material and Methods: The study was conducted on 100 Acinetobacter baumannii strains isolated from clinical samples. The Isolates were identified by standard methods and confirmed by PCR method. Drug resistance pattern of isolates was determined by standard disk diffusion method according to CLSI. To identify ESBL producing strains, a Combined Disk phenotypic method was used.
Results: Hundred percent of Acinetobacter baumannii strains was MDR and the maximum antibiotics resistance was shown to cefepime, co-trimoxazole, ciprofloxacin, meropenem and ceftazidime. According to initial screening, 4.5% of strains were producing Extended Spectrum Beta Lactamase enzyme.
Conclusion: The percent of ESBLs producing strains is low. Thus, Combined Disk for initial screening of ESBLs strains and multiplex PCR for rapid detection of ESBLs strains are recommended. This issue can be a new step in preventing from the spread of Acinetobacter Baumannii Strains in hospitals particularly in intensive care unit.
Keywords: Beta-Lactamases; Acinetobacter Baumannii; Drug Resistance
Roya Rafiee , Fereshte Eftekhar , Seyed Ahmad Tabatabaei , Dariush Minaee-Tehrani ,
Volume 10, Issue 3 (5-2016)
Abstract
ABSTRACT
Background and Objectives: Pseudomonas aeruginosa is the most frequent opportunistic pathogen isolated from the sputum of patients with cystic fibrosis (CF). Resistance to β -lactam antibiotics may arise from over expression of the naturally occurring AmpC cephalosporinases or acquired extended-spectrum β-lactamases (ESBL). The aim of this study was to determine the antibiotic resistance profiles as well as the prevalence of ESBL and AmpC production in clinical isolates of P. aeruginosa from CF patients in Tehran.
Methods: Antibiotic resistance of 50 non-duplicate P. aeruginosa isolates was determined by the disc diffusion method. AmpC β-lactamase production was detected by the antagonism disc test and ESBL production was detected by the phenotypic confirmatory test. The presence of ESBL and AmpC genes was assessed by PCR, followed by sequencing the PCR products.
Results: The antibiotic resistance rates were as follows: 22% to ceftriaxone, 20% to cefotaxime, 10% to imipenem, 8% to carbenicillin and 6% to ticarcillin, 4% each to cefepime, tobramycin, amikacin and aztreonam and 2% to each piperacilin, meropenem and ceftazidime. AmpC production was observed in 47 isolates (94%) and ESBL production was observed in one isolate (2%). PCR results showed that all isolates carried the blaAmpC β-lactamase gene. One multidrug-resistant isolate carried both blaTEM and blaPER-1 genes.
Conclusion: The results showed that despite the low rate of antibiotic resistance in P. aeruginosa CF isolates,the presence of multiple β-lactamases even in one isolate is alarming and can complicate the already difficult treatment of chronic infections in the lungs of CF patients.
Seyed Amin Enayatzadeh Meymandi, Laleh Babaeekhou, Maryam Ghane,
Volume 13, Issue 5 (9-2019)
Abstract
ABSTRACT
Background and Objectives: Emergence and spread of multidrug-resistant (MDR) and extensively-drug resistant (XDR) Pseudomonas aeruginosa strains could complicate antipseudomonal chemotherapy. Dissemination of resistance genes, such as β-lactamases encoding genes by horizontal gene transfer can lead to development of multi-drug resistance in P. aeruginosa. The purpose of this study was to investigate the latest resistance patterns in MDR and XDR strains and evaluate Ambler class A β-lactamase gene distribution in P. aeruginosa clinical isolates.
Methods: One hundred molecularly and biochemically identified P. aeruginosa strains isolated from different clinical specimens were tested for sensitivity to 17 antibiotics using the Kirby-Bauer disk diffusion method. PCR was performed to detect bla TEM-1, bla SHV-1, bla REP-1 and bla VEB-1 genes. Results were analyzed using SPSS and NTSYSpc softwares.
Results: Based on the results of antibiogram, the highest rate of resistance was observed against amikacin (100%), aztreonam (83%), ceftazidime (55%), cefepime (55%) and netilmicin (48%). In addition, the frequency of MDR and XDR isolates was 95% and 5%, respectively. The blaSHV-1, bla TEM-1, bla PER-1 and bla VEB-1 genes were detected in 31%, 24%, 13% and 10% of the isolates, respectively.
Conclusion: Antibiotic resistance to β-lactam antibiotics and frequency of β-lactamase genes were relatively high in the study area. We also found that a significant proportion of XDR strains with different antibiotic resistance profile is isolated from tracheal specimens.
KEYWORDS: Pseudomonas aeruginosa, Beta-Lactamase, Multidrug Resistant, Extensively Drug Resistant.
Arvin Shajeie, Mehrnaz Rad, Mahdi Askari, Kamran Sharifi, Gholamreza Hashemi Tabar,
Volume 17, Issue 5 (9-2023)
Abstract
Background: Colistin is the most significant last-line antibiotic for the treatment of multidrug-resistant infections caused by Gram-negative bacteria, especially the Enterobacteriaceae family. The emergence and rapid spread of the plasmid-mediated resistance gene, mcr-1 (mobilized colistin resistance), in some isolates of Escherichia coli in recent years provoked public health concerns since it has been shown that mcr-1 with other resistance genes, such as ESBLs (extended-spectrum beta-lactamases) and carbapenemases, could be carried on a single plasmid concurrently. The excessive consumption of colistin, particularly in the livestock industry, and the transmission of these resistant bacteria from livestock to humans may potentially increase the risk of the spread of resistance in humans. Therefore, this study aimed to detect the prevalence of mcr and carbapenem resistance genes among neonatal calves in Mashhad, Razavi Khorasan Province, Iran.
Methods: In the current study, 200 fecal samples from healthy and diarrheic neonatal calves (≤35 days old) were collected in Mashhad (190 E. coli strains were isolated). Antibiotic susceptibility to ceftazidime, cefepime, cefixime, meropenem, colistin, and ciprofloxacin was examined. The double-disk diffusion method (ceftazidime + ceftazidime/clavulanic acid) was performed on Mueller-Hinton agar (MHA) media to phenotypically distinguish the ESBL producers. Afterward, the Multiplex polymerase chain reaction (PCR) method was used to detect colistin resistance genes (mcr-1, mcr-2, mcr-3, mcr-4, and mcr5), NDM-1 (New Delhi metallo-beta-lactamase 1), and OXA-48 as carbapenemases.
Results: The results of the resistance rate to antibiotics were cefepime, ceftazidime, cefixime, meropenem, and colistin. Based on the findings, 33.7% were phenotypically ESBL producers, 4.21% harbored mcr-1, and no NDM-1 or OXA-48 was detected. Among the mcr-1-positive isolates, 5 strains showed the ESBL phenotype.
Conclusion: The results highlight the need for continued monitoring of antibiotic resistance in livestock and the potential for transmission to humans. The findings also underscore the importance of responsible antibiotic use in both human and animal health to mitigate the spread of antibiotic resistance.
Kirandeep Kaur,
Volume 18, Issue 3 (5-2024)
Abstract
Escherichia coli is a Gram-negative, rod-shaped bacterium, responsible for 90% of all community-acquired infections and 50% of hospital-acquired infections, with opportunistic infections found in intensive care unit (ICU) patients. The β-lactam antibiotics, which inhibit cell wall synthesis, are known for their high efficacy and broad-spectrum activity. They also have low toxicity and provide long-term effects, making them widely used drugs against Gram-negative bacteria. Bacteria develop resistance to β-lactams primarily through the expression of hydrolytic enzymes, called β-lactamases, which are divided into serine β-lactamases (Classes A, C, and D) and metallo-β-lactamases (Class B), based on their molecular mechanism. This study aimed to clarify the mechanism of action of β-lactams against Gram-negative bacilli and to emphasize the multidrug resistance of cephalosporins and carbapenems to E. coli.
Elmira Shah Cheraghi, Mozhgan Ghiasian ,
Volume 18, Issue 6 (11-2024)
Abstract
Background: Pseudomonas aeruginosa (P. aeruginosa) is a common causative agent of hospital-acquired infections and exhibits resistance to many antibiotics, including beta-lactams. One of the mechanisms of resistance to beta-lactams is the MexAB-OprM efflux pump. This study investigated the genetic pattern of resistant P. aeruginosa strains concerning the presence of the gene encoding the MexAB-OprM efflux pump
Methods: This descriptive-analytical study was conducted between 2022 and 2023 in Isfahan, and 110 strains of P. aeruginosa isolated from various clinical samples were identified. Antibiotic susceptibility testing of the isolates was conducted using the disk diffusion method, and strains producing extended-spectrum beta-lactamases (ESBLs) were identified using the double disk diffusion method. The gene encoding the MexAB-OprM efflux pump in these strains was investigated using polymerase chain reaction.
Results: A significant proportion of the 101 P. aeruginosa isolates originated from the emergency department and ICU-2, highlighting the clinical significance of this pathogen in these settings. Meropenem demonstrated a high resistance rate (74%), while gentamicin exhibited lower resistance (33.33%). Resistance rates to amikacin, levofloxacin, cefepime, ceftazidime, tazocin, ciprofloxacin, and ceftriaxone were 40.4%, 68%, 65.34%, 66.33%, 57.42%, 71.42%, and 50%, respectively. The prevalence of extended-spectrum beta-lactamases (ESBLs) was 29.7%, and the MexAB-OprM efflux pump gene was identified in 80% of ESBL-producing strains, suggesting a potential role in multidrug resistance.
Conclusion: Our findings reveal a strong association between the presence of the MexAB-OprM efflux pump and extended-spectrum beta-lactamase production in P. aeruginosa. This observation suggests that the MexAB-OprM efflux pump plays a pivotal role in the development of multidrug resistance in this pathogen. Future studies should focus on elucidating the molecular mechanisms underlying the regulation and function of this efflux system to inform the design of novel antimicrobial agents and combination therapies.
