جستجوی مقالات مرتبط با کلیدواژه « Antibiotic resistance » در نشریات گروه « پزشکی »

Urinary tract infections (UTIs), one of the most prevalent bacterial infections, are facing limited treatment options due to escalating concern of antibiotic resistance. Urine cultures significantly help in identification of etiological agents responsible for these infections. Assessment of antibiotic susceptibility patterns of these bacteria aids in tackling the emerging concern of antibiotic resistance and establishment of empirical therapy guidelines. Our aim was to determine various agents responsible for urinary tract infections and to assess their antibiotic susceptibility patterns.

This cross-sectional study was performed over a period of six months from January 2023 to July
2023 in Department of Microbiology of Pakistan Institute of Medical Sciences (PIMS).

Out of 2957 positive samples, Gram negative bacteria were the most prevalent in 1939 (65.6%) samples followed by Gram positive bacteria in 418 (14.1%) and Candida spp. in 269 (9.1%) samples. In gram negative bacteria, Escherichia coli (E. coli) was the most prevalent bacteria isolated from 1070 samples (55.2%) followed by Klebsiella pneumoniae in 397 samples (20.5%). In Gram positive bacteria, Enterococcus spp. was the most common bacteria in 213 samples (51%) followed by Staphylococcus aureus in 120 samples (28.7%). Amikacin was the most sensitive drug (91%) for Gram negative bacteria. Gram positive bacteria were most susceptible to linezolid (97%-100%).

The generation of a hospital tailored antibiogram is essential for the effective management of infections and countering antibiotic resistance. By adopting antimicrobial stewardship strategies by deeper understanding of sensitivity patterns, we can effectively combat antibiotic resistance.

Staphylococcus aureus is one of the most important public health risks as it causes many forms of infection. Treatment options for infections caused by this pathogen are limited due to the development of resistance to commonly used antibiotics. This study aimed to investigate the antibiotic resistance patterns in Staphylococcus aureus strains.

In this cross-sectional study conducted between 2020 and 2023, 348 Staphylococcus aureus specimens were isolated from clinical samples at Aliebne Abitaleb Hospital in Zahedan, Iran. Following the identification of the strains, their antibiotic resistance to eight antibiotics was assessed by the disk diffusion method based on Clinical Laboratory Standard Institute 2022, and the MRSA isolates were screened. Additionally, Vancomycin's MIC was evaluated using the E-test. Statistical analysis was conducted using the chi-square test using SPSS, version 16 (IBM SPSS, Armonk, NY, USA).

Of the 348 isolated S. aureus strains (171 from males and 177 from females), 163 (50%) were from blood cultures, and 53 (15.2%) were from tracheal samples. The strains showed the highest resistance to erythromycin (77.9%) and penicillin (100%). The samples had the lowest resistance to cotrimoxazole (36.2%) and nitrofurantoin (29.6%). Additionally, all strains were susceptible to vancomycin.In this study, 76% and 30% of the examined strains could be classified as MDR and XDR, respectively. There was no significant association between age, gender, and MRSA infection (P > 0.05).

In this study, cotrimoxazole showed considerable activity against MRSA strains. Moreover, since all isolates were susceptible to vancomycin, this antibiotic could be the primary treatment choice. The high prevalence of MDR strains is a significant cause for concern.

Escherichia coli O157: H7 is one of the most important causes of hemorrhagic colitis, and hemolytic uremic syndrome. The present study aimed to isolate E. coli O157: H7 from foods and patients with hemorrhagic colitis, and identify Shiga toxin genes, phylogenetic comparison, and antibiotic resistance of the isolates.

In total 400 samples, including patients stool and food were taken in Isfahan-Iran province. Pheno- typic tests and PCR were performed to identify Shiga toxin-producing E. coli. The isolated strains were compared phyloge- netically by PFGE. Agar disk diffusion was performed to identify the antibiotic resistance of the isolates.

Totally, 5 isolates of fecal samples were E. coli O157, but only 2 isolates carried H7 gene. Also, 9 isolates of E. coli O157 were isolated from food samples that 3 isolates were E. coli O157: H7. The isolates carried stx1, stx2, hlyA and eaeA genes. Also, E. coli non-O157: H7 identified from samples that contained stx1, stx2, hlyA genes. The highest susceptibility to imipenem and the highest resistance to ampicillin and ciprofloxacin were observed. There was a similarity of 100% between the E. coli O157: H7 strains isolated from patients and raw milk and minced beef samples.

Serotypes other than the O157 of E. coli are more prevalent in patients and food. The E. coli O157: H7 isolates from patients had 100% genetic similarity with minced meat and cow milk isolates, which indicates cattle are the most im- portant reservoir of this bacterium in Iran.

Pseudomonas aeruginosa, drug-resistant, causes health infections. Resistance to the preferred therapy meropenem is a serious threat. This study aimed to analyze changes in meropenem minimum inhibitory concentra- tion (MIC), changes in ampC, mexA, and oprD gene expression, and the correlation between MIC and ampC, mexA, and oprD gene expression after meropenem exposure.

Ten isolates of P. aeruginosa from the Clinical Microbiology Department, Faculty of Medicine, Universitas Indonesia were used. After the bacteria were shown to be sensitive to meropenem phenotypically, intrinsic resis- tance genes were detected using PCR. After meropenem exposure on Days 5 and 12, sensitivity testing was carried out with the concentration gradient method and RNA was detected using real-time RT-PCR.

All P. aeruginosa isolates that were phenotypically sensitive to meropenem had the ampC, mexA, and oprD genes. An increase in MIC, an increase in ampC and mexA gene expression, and a decrease in oprD gene expression were observed after meropenem exposure. There was a very strong and significant correlation (p ≤ 0.05) between MIC and oprD gene ex- pression after Day 12 of meropenem exposure.

Although there were no significant differences in MIC and ampC, mexA, and oprD gene expression between Day 5 and Day 12, there was a very strong and significant correlation between MIC and oprD gene expression on Day 12 (p ≤ 0.05). This indicates that decreasing oprD gene expression has the potential to increase meropenem resistance in Pseudo- monas aeruginosa.

This study aimed to investigate the prevalence and potential risk factors of Staphylococcus aureus nasal carriage in household pets (cats and dogs) and their owners in Chlef province in Algeria and to determine the isolates antibiotic resistance profiles.

S. aureus was isolated from nasal swabs, identified by culture on mannitol salt agar (MSA), and confirmed by polymerase chain reaction (PCR) amplification of the nuc gene. Methicillin-resistant S. aureus (MRSA) isolates were identified by their resistance to cefoxitin and PCR targeting the mecA gene. Panton-Valentine leukocidin (PVL) toxin genes were screened by PCR. Antimicrobial resistance was determined by disc diffusion method. The effect of risk factors on S. aureus nasal carriage was evaluated using a multivariable generalized linear model (GLM).

A total of 110 nasal swabs were collected: 29, 31, and 50 from dogs, cats, and their owners, respectively. The nasal carriage rate of S. aureus was 25% in household pets (22.6% in cats and 27.6% in dogs) and 22% in their owners. MRSA isolates were recovered only from pets (6.6%); 25% of them were multidrug resistant (MDR). One MDR MRSA isolate was PVL-positive. The age of dogs was the only risk factor significantly associated with S. aureus nasal carriage.

The results revealed that nasal carriage of S. aureus in household pets was relatively high, raising concern about their potential risk to human health and stressing the importance of active surveillance of S. aureus carriage in pets.

The widespread use of antibiotics for growth promotion or therapeutic purposes in poultry farming has led to increased antibiotic resistance. Escherichia coli is one of the gastrointestinal bacteria capable of transferring resistance genes and causing antibiotic resistance in humans and poultry. Evaluating antibiotic resistance in poultry flocks can provide researchers with a clear picture of the health status of poultry flocks and the human community. 

This study was conducted on 60 broiler chicken flocks aged 1 to 28 days. These flocks had no history of antibiotic use. In the laboratory, after necropsy, sampling was carried out from five chicken pieces in each flock. After confirming the diagnosis and purification of E. coli using biochemical methods, antibiotic sensitivity testing against 19 antibiotics was performed using the disc diffusion method, following the CLSI guidelines. 

Out of 300 samples collected, 270 (90%) isolates of E. coli were obtained. In this study, the sensitivity of antibiotics was as follows: fosfomycin (100%), lincomycin (94.81%), neomycin (48.52%), amoxicillin (48.15%), norfloxacin (41.48%), thiamphenicol (38.52%), enrofloxacin (38.52%), sulfamethoxazole (36.66%), florfenicol (31.85%), tilmycosin (31.85%), danofloxacin (30%), flumequine (25.19%), difloxacin (21.85%), chlortetracycline (16.66%), trimethoprim (16.66%), doxycycline (11.85%), erythromycin (10%), tylosin (1.48%), and colistin (0%). Additionally, resistance was observed only against tylosin (91.85%). No multiple resistance was observed among the isolated strains, and at least sensitivity to two antibiotics was detected in all samples. 

The findings of this research indicate that the level of antibiotic resistance in broiler chicken flocks at young ages in the Kermanshah region is low. However, the sensitivity rate to 17 antibiotics is less than 50%, demonstrating a relatively high level of sensitivity in poultry at these ages.

Uropathogenic Escherichia coli is one of the most important causes of urinary tract infections. These strains possess various virulence factors, including adhesins, toxins, and iron acquisition systems. Virulence genes are situated on mobile genetic elements or in specific regions of the chromosome known as pathogenicity islands. In this study, 375 clinical samples from male and female patients suspected of having urinary tract infections were collected in the hospitals of Dhi Qar, Iraq, during the period from June 1, 2019, to November 1, 2019. Following the collection of 100 samples, bacterial isolation, DNA extraction, and antibiotic sensitivity tests were conducted using the disc diffusion method with the selected antibiotics. The presence of papC, aer, fimH, hly, cnf-1, and afa class genes was investigated using multiplex PCR. The results indicated that the highest frequency among the genes was associated with the fim gene (98%). The aer, papC, cnf-1, hly, and afa genes were also detected, with frequencies of 52%, 30%, 18%, 13%, and 11%, respectively. Additionally, the highest resistance and sensitivity among UPEC isolates were observed for amoxicillin (82.37%) and amikacin (92.35%) antibiotics, respectively.

 The emergence of multidrug-resistant (MDR) Shigella is a health concern in both developed and developing countries. The indiscriminate use of antibiotics without considering resistance patterns has led to the emergence of resistant strains.

 This study aimed to investigate the phenotypic and genotypic patterns of antibiotic resistance and virulence gene distribution in Shigella isolates from patients in Tehran, Iran.

 In this cross-sectional study, 60 Shigella isolates were collected from patients referred to Milad Hospital and Pasargad Laboratory in Tehran. The isolates were gathered over four months, from February 2023 to June 2023. After biochemical and genetic confirmation of the isolates, the disk diffusion method was employed to determine antibiotic resistance patterns. The distribution of beta-lactamase genes (bla CTX-M1, bla CTX-M2, bla CTX-M8, bla SHV, bla TEM, and bla OXA) and virulence genes (ial, virF, invE, sigA, and pic) was investigated in Shigella isolates using the multiplex PCR method. SPSS statistical software version 22 was used for data analysis.

 Thirty-six percent of isolates were found to be MDR. The highest rate of resistance was against tetracycline (90%) and ampicillin (80%). The lowest resistance rate was against azithromycin (1.9%) and amikacin (7.1%). The bla CTX-M1 and bla CTX-M8 genes were more prevalent, detected in 38.3% and 50% of the isolates, respectively. However, the bla SHV and bla CTX-M2 genes were not detected in any of the isolates. Additionally, 32% of the MDR isolates harbored both the bla CTX-M1 and bla CTX-M8 genes simultaneously. The distribution of virulence genes ial, virF, invE, sigA, and pic in the studied isolates was 28.3%, 85%, 68.3%, 81.7%, and 15%, respectively.

 The present study emphasizes the increasing trend of MDR Shigella isolates. Therefore, serious measures are needed to prevent the spread of resistant genes. Furthermore, the detection of virulence factors could help in controlling shigellosis, which is a significant global health issue.

Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection in humans including cystitis and pyelonephritis. Antimicrobial resistance (AMR) in UPEC is one of the global public challenges that is due to prevalent use of antibiotics in healthcare setting. Therefore, the purpose of this study is to investigate the frequency and antibiotic resistance pattern of UPEC isolated from patients admitted to Modares Hospital in Saveh, Iran.

In this study, in total 633 isolates were evaluated. UPEC isolates were obtained from patients with urinary tract infection and identified using conventional microbiological protocols. Antibiotic resistance pattern of UPEC against different antibiotic were determined using disk diffusion method. SPSSTM software was used for statistical analysis.

In this study, the most sample was related to outpatients and the lowest sample was related to the CCU wards. The highest antibiotic resistance showed against cephalothin (63.8%) and nalidixic acid (62.2%) antibiotics. The highest effective antibiotics for the tested UPEC was nitrofurantoin (90.7%) and gentamicin (77.3%). Cephalothin and nalidixic acid in hospitalized patients in ICU and emergency wards, respectively, showed the highest antibiotic resistance. Out of 633 UPEC, the rate of Multi Drug Resistant (MDR) isolates were 343 (54.2%).

The result of this study highlighted the role of UPEC as one of the important cause of UTI in individuals. Also, nitrofurantoin then gentamicin are the most effective antibiotics against UPEC infections. Logical prescription of antibiotics and infection control strategies are needed for prevention and control of nosocomial infections especially urinary tract infection.

 Pseudomonas aeruginosa significantly contributes to hospital-acquired infections.

 This study aimed to investigate the genetic diversity of P. aeruginosa strains using multiple-locus variable-number tandem repeat analysis (MLVA) and to explore the relationship between biofilm production and antibiotic resistance.

 In this cross-sectional study, 79 P. aeruginosa isolates were collected. Antibiotic sensitivity was tested using the Kirby-Bauer method, and biofilm production capability was assessed through the microtiter plate method. Genetic diversity was evaluated by MLVA, analyzing eight variable-number tandem repeat (VNTR) loci: MS-213, MS-214, MS-207, MS-217, MS-222, MS-209, MS-77, and MS-172. Phylogenetic relationships were delineated using PHYLOViZ 2.0 software.

 The patient cohort comprised 51.9% males, with the majority of samples (35.4%) obtained from urine. Ceftazidime (CAZ 30µg) showed the highest resistance rate at 77.2%. Notably, 92.4% of isolates were capable of forming biofilms, categorized as 22.7% weak, 28.7% moderate, and 46.5% strong. Phylogenetic analysis demonstrated variability across one or more VNTR loci. Simpson’s index (0.906) and Shannon-Weiner diversity indices (H: 3.466, J: 0.910, Hmax: 3.807, Hmin: 1.242) identified MS77 as the most informative marker for genetic diversity among the isolates.

 The study highlights an alarming trend in antibiotic resistance, underscoring the necessity of regular monitoring. The findings confirm that MLVA is a straightforward, rapid genotyping method suitable for assessing the genetic diversity of P. aeruginosa.

 Bacterial infections are the most frequently occurring infections in pets. Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) have been recognized as two opportunistic pathogens that are prevalent in pets. The aforementioned organisms play a vital role in the development and propagation of infections that affect the urinary tract, respiratory system, and gastrointestinal tract. The growing emergence of multidrug resistance among the bacteria is a global concern. The investigation of antibiotic resistance and genotypic characterization of Extended- spectrum β-lactamases (ESBLs) and Metallo - β - lactamase (MBL) - producing Enterobacteriaceae (CPE) in companion animals in Iran has been infrequently documented. The aim of this study was to identify the phenotypic and genotypic characterization of ESBL and MBL - producing Escherichia coli and Klebsiella pneumoniae strains that were isolated from dogs and cats stool.

 A total of 65 stool samples of dogs and cats were collected from five veterinary hospitals between February to August 2022. The antimicrobial susceptibility test (AST) was evaluated by using disk diffusion according to The Clinical and Laboratory Standards Institute guidelines (CLSI). The detection of ESBLs and MBLs producing isolates was performed by Combination Disk Diffusion Test (CDDT). The presence of blaCTXM, blaTEM,blaSHV, blaNDM, blaVIM, blaIMP genes was detected by PCR technique.

 Among 65 samples, 24 E. coli and 6 K. pneumoniae strains were identified. According to our findings, the most effective antibiotics against bacterial isolates were piperacillin - tazobactam imipenem and meropenem, respectively. The prevalence of ESBL and MBL was found to be 66.66% and 0%, respectively. The PCR assay revealed the presence of blaCTXM-15, blaTEM, blaSHV, blaIMP genes 28, 28, 18, 1 number, respectively. Whereas blaNDM, and blaVIM genes were not detected.

 The increasing prevalence of antibiotic resistance genes is a significant concern in the field of medicine. The excessive utilization of antibiotics may lead to the acquisition of genes that contribute to resistance.

Biofilm formation is crucial in the pathogenesis of Pseudomonas aeruginosa infections, contributing to increased antibiotic resistance.

This study aimed to evaluate the expression of the PA0756 and toxA genes in clinical isolates of P. aeruginosa, comparing biofilm-producing isolates with planktonic ones.

In this cross-sectional study, 160 clinical isolates of P. aeruginosa were collected from hospitals in Tabriz. Biofilm development was assessed using a 96-well flat-bottom microtiter plate test, followed by polymerase chain reaction (PCR) amplification of the resistance genes PA0756 and toxA. DNA synthesis for both biofilm and planktonic P. aeruginosa was conducted, with the quantification of target genes carried out using real-time PCR with specific primers.

Of the isolates, 139 (87%) formed biofilms. These strains showed high resistance to gatifloxacin, piperacillin, gentamycin, and ceftazidime (82.25%, 72.97%, 76.12%, and 74.63%, respectively), while resistance to colistin and polymyxin B was low (2.5% and 3%, respectively). The expression study revealed significant upregulation of the PA0756 and toxA genes in biofilm formers by 1.2 - 5.6 fold and 1.2 - 2.5 fold, respectively, compared to planktonic cells (P = 0.012 and P = 0.041, respectively).

The PA0756 and toxA genes are significantly involved in biofilm-specific antibiotic resistance in P. aeruginosa, presenting potential targets for therapeutic interventions against antibiotic resistance caused by this pathogen.