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.
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.
