antibiotic resistance

Biofilms are organized communities of microorganisms encased in a self-produced matrix that adheres to surfaces and can have both beneficial and detrimental effects in various environments. These biofilms have been linked to severe infections in humans. We investigated the association between antibiotic resistance and biofilm formation in methicillin-resistant Staphylococcus epidermidis (MRSE) isolates.

A comprehensive search was conducted through data medical data bases using a combination of mesh terms. The data were analyzed using STATA meta-analysis software, and a random effects model was employed to determine the pooled prevalence with a 95% confidence interval (CI).

Our findings revealed that the prevalence of MRSA was 61.75% (95% CI: 35.6-99.1). The cumulative rate of biofilm formation in MRSE strains was reported to be 83.4% (95% CI: 47.8-99.4). Among the biofilm-related genes, the SdrG gene exhibited the highest frequency (98%), followed by the atlG gene with a frequency of 84%.

Out of the seven, three documented a positive association. Given the propensity of MRSE strains to form biofilms, it is crucial to implement preventive measures against infections caused by these strains.

Wastewater from slaughterhouses serves as a reservoir for various Escherichia coli pathotypes, including enterotoxigenic (ETEC), enteropathogenic (EPEC), and enterohemorrhagic (EHEC) strains, which pose significant public health risks. This study aimed to isolate and molecularly identify common E. coli pathotypes in slaughterhouse wastewater and assess their antibiotic resistance patterns.

A total of 58 E. coli isolates were collected from wastewater samples at local slaughterhouses. The isolates were subjected to molecular identification using a polymerase chain reaction targeting specific virulence genes associated with E. coli pathotypes. Antibiotic susceptibility testing was performed using the disk diffusion method against commonly used antibiotics.

The analysis of virulence genes in E. coli isolates revealed significant insights into the pathogenicity and potential health risks associated with these bacteria. A total of 58 isolates were analyzed for the presence of virulence genes. Among these, 20 (34.4%) were positive for the eae gene (EPEC), 5 (8.6%) for stx1 + stx2 (EHEC), and 4 (6.8%) for estA2-4 (ETEC). No isolates were positive for the elt gene. Additionally, 29 isolates (50.2%) did not carry any of the targeted virulence genes (eae, stx1 + stx2, estA2-4, or elt). The antibiotic resistance profile of E. coli isolates demonstrated significant resistance rates to commonly consumed antibiotics. Among the 58 isolates, resistance was observed to streptomycin (63.7%), kanamycin (39.6%), imipenem (51.7%), and notably erythromycin (100%). Additionally, 92% of virulence gene-positive isolates were multidrug-resistant, with four isolates exhibiting extensive resistance to all tested antibiotics.

The findings highlight the prevalence of pathogenic E. coli strains in slaughterhouse wastewater and their resistance to multiple antibiotics, underscoring the potential health risks they pose and the need for effective management strategies to mitigate their impact on public health.

Klebsiella pneumoniae is a Gram-negative opportunistic pathogen and a common cause of nosocomial infections. The present study aimed to investigate the distribution, antibiotic resistance patterns, resistance genes, capsular types, and genotypes of K. pneumoniae isolates.

A total of 872 clinical samples were collected from inpatients across various hospital wards in Amol, northern Iran. K. pneumoniae isolates were identified and tested for antibiotic susceptibility. Capsular typing and detection of resistance genes were performed, and enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) was used to type the isolates.

K. pneumoniae was isolated from 70 out of 872 samples (8.04%), with the highest prevalence in urine (58.6%) and sputum (25.7%). High resistance rates were observed against erythromycin (98.6%), ampicillin (92.9%), and cefazolin (68.6%), while no resistance to colistin was detected. Multidrug-resistant (MDR) was found in 55.71% of isolates, and 15.71% were extensively drug-resistant (XDR). Carbapenem-resistant K. pneumoniae (CRKP) accounted for 55.7% of the isolates. The most prevalent capsular type was the K57. Forty-eight resistance gene patterns were detected, with the tetB gene present in all isolates, whereas the mcr and blaVEB genes were not detected. ERIC-PCR genotyping revealed 24 different clusters in the phylogenetic dendrogram.

This study highlights the prevalence of antibiotic-resistant K. pneumoniae strains exhibiting significant clonal diversity among isolates from hospital wards in Iran. The findings underscore the need for more stringent infection control measures and management practices related to the misuse of antibiotics to tame the rampant resistant K. pneumoniae in hospitals. These results are compatible with the globally prevailing phenomenon of increased resistance and further emphasize the necessity for sustained, in-depth intelligence-gathering processes and multicenter investigations to decode patterns on a regional and international scale.

The genus Providencia, a member of the Enterobacteriaceae family, has emerged as a significant pathogen in human infections, particularly in immunocompromised individuals and hospital settings. With increasing global reports of antimicrobial resistance in Providencia species, understanding the resistance patterns and mechanisms in specific geographic regions is critical. This review evaluated the antibiotic resistance status of Providencia spp. in Iran, summarizing findings from existing literature to identify trends, gaps, and implications for public health and clinical practice.

For this purpose, Google, PubMed, and Scopus databases were searched, along with conducting a systematic review of peer-reviewed articles, clinical case reports, and surveillance studies to assess the antibiotic resistance profiles of Providencia in Iran. Studies published from 2000 to 2024 were included in this review, with a focus on Providencia resistance to critical antibiotics such as carbapenems, cephalosporins, fluoroquinolones, and the like, which are multidrug resistant (MDR) or pandrug resistance (PDR) Providencia based on CLSI performance guidelines for antimicrobial susceptibility testing. The data were analyzed to identify prevalent resistance genes, mechanisms, and regional variations.

The findings revealed a concerning rise in MDR among Providencia isolates in Iran, with resistance to carbapenems, fluoroquinolones, aminoglycosides, and extended-spectrum beta-lactams frequently reported. Regional studies highlight variability in resistance rates, likely reflecting differences in antimicrobial stewardship and healthcare practices. Emergency PDR Providencia is a serious health threat due to its intrinsic resistance to some antibiotics, such as colistin, and tigecycline, which are used for other MDR Enterobacteriaceae species. Accordingly, understanding regional resistance patterns is helpful in choosing the appropriate treatment option.

Given the high rate of carbapenem resistance, this is likely substantiated by other studies conducted in Asia that have identified various carbapenemases, including VIM, IMP, NDM-1 MBL, OXA-48, and KPC, which underscores the urgent need for effective antimicrobial stewardship and surveillance strategies to combat the spread of these resistant pathogens.

Hospital-acquired infections (HAIs), specifically those caused by gram-negative bacteria, are a significant public health concern with high mortality rates among patients worldwide, especially in developing countries.

This survey aimed to determine the prevalence and antibiotic resistance patterns of gram-negative nosocomial infections among patients admitted to different wards of a tertiary hospital in Iran.

This cross-sectional study was conducted using samples collected from patients admitted to coronary care unit (CCU), intensive care unit (ICU), neonatal intensive care unit (NICU), general, and surgery wards of Yas Hospital, Tehran, Iran, from October 1st, 2022, to February 28th, 2023. After the detection of bacteria, antibiotic susceptibility tests were performed using the Kirby-Bauer disk diffusion method by the guidelines of the clinical and laboratory standards institute (CLSI) for gentamycin (GM), ciprofloxacin (CIP), cefepime (FEP), ceftazidime (CAZ), cefotaxime (CTX), imipenem (IPM), meropenem (MR), and piperacillin-tazobactam (TZP), and the results were analyzed using SPSS v22 software.

Two hundred and sixty isolates were collected from clinical specimens, most of which were isolated from the ICU ward (53.8%). Among the collected specimens, 98 (37.7%) were isolated from urine, 92 (35.4%) from sputum, 45 (17.3%) from blood, 17 (6.5%) from surgical wounds, and 8 (3.1%) belonged to other specimen types. Among detected bacteria, Klebsiella pneumoniae and Escherichia coli were found to be responsible for 78% of total infections. Based on the Kirby-Bauer disk diffusion results, Acinetobacter baumannii demonstrated the highest resistance to the antibiotics tested, with a resistance rate ranging from 92% to 97%. This was followed by K. pneumoniae, which demonstrated resistance rates between 70% and 85% across all classes of tested antibiotics.

The study highlights a high prevalence of nosocomial infections in the ICU, with significant antibiotic resistance, particularly from A. baumannii. It emphasizes strict hospital monitoring, infection control, and responsible antibiotic use.

The gallnut is a plant that has antimicrobial effects. This study investigated the inhibitory effect of the gallnut extract combined with two biosurfactants (SG and 12B) on pathogenic bacteria in the planktonic form and biofilm.

The disc diffusion method was used for the antimicrobial activity assay. In addition, the minimum inhibitory and minimum bactericidal concentrations of compounds were determined by the macro-dilution method. Biofilm inhibition and destruction were measured using the microtiter plate method.

The results revealed that the gallnut extract had inhibitory effects on pathogenic bacteria alone. Further, two biosurfactants (SG and 12B) had sufficient antimicrobial activity. The highest and lowest inhibitory effects were observed against Staphylococcus aureus and Bacillus cereus, respectively. The combination of the gallnut extract with each biosurfactant increased antibacterial activity compared to a single mixture (86% inhibition compared to 53%). The results of antibiofilm activity confirmed that the biofilm of Acinetobacter had the highest sensitivity (93% inhibition), while the lowest sensitivity belonged to the Escherichia coli biofilm (23% inhibition).

Overall, the combination of plant extracts with biosurfactants could increase the inhibitory effect of plant extracts and thus can be applied to design some safe antimicrobial agents.

 Due to the increasing demand for new antibiotics, extensive research is being conducted on various compounds, particularly plant-based compounds. Among them, plant essential oils (EOs) have been investigated for their antibacterial properties in numerous studies. Accordingly, the inhibitory and bactericidal effects of Cuminum cyminum and Foeniculum vulgare EOs on two bacterial species, Escherichia coli and Listeria monocytogenes, were examined in this study.

 The compounds present in these extracts were evaluated using gas chromatography-mass spectrometry analysis. Subsequently, molecular docking methods were employed to depict the interactions of these compounds with the active site of the beta-lactamase enzyme of these bacteria in three-dimensional illustrations.

 Laboratory methods such as disk diffusion agar, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) revealed that although the bactericidal properties of these extracts were weak, they exhibited strong growth inhibitory properties, particularly the effect of F. vulgare EO on L. monocytogenes (MIC=1/104). Additionally, with the presence of p-cumin aldehyde at 33.7% in the cumin extract and trans-anethole at 46.5% in the fennel extract, molecular docking analyses showed that the binding ability and antibacterial properties of the cumin extract against E. coli by two hydrogen bonds and fennel extract against L. monocytogenes by two hydrogen bonds were more pronounced considering the level of binding energies.

 Although the extracts represented weak bactericidal properties, their strong inhibitory effects on bacterial growth, especially with F. vulgare EO on L. monocytogenes, are notable. Moreover, the active compounds, such as p-cumin aldehyde and trans-anethole, demonstrated significant potential as alternative antibacterial agents.

The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Pseudomonas aeruginosa represents a significant challenge to current antibiotic therapies, particularly in immunocompromised patients, leading to severe and potentially fatal infections.

The present study aims to investigate the association between resistance patterns, the presence of the algD, pelF, and pslD genes, and biofilm formation capabilities among clinical isolates of P. aeruginosa.

A total of 25 clinical strains of P. aeruginosa were isolated from clinical specimens. An antibiotic sensitivity test was conducted to categorize the organisms as resistant (R), MDR, and XDR strains. A biofilm formation assay was performed to evaluate biofilm formation capacity, and the algD, pelF, and pslD genes were detected using a polymerase chain reaction (PCR) technique.

All 25 clinical isolates showed the highest resistance against meropenem (MEM) (100%), imipenem (IPM) (96%), and ceftazidime (CAZ) (72%). Antimicrobial resistance (12%) and MDR (12%) strains were more prevalent in the 51 - 60 and 71 - 80 age groups, while the highest MDR (16%) strains were detected in the 81 - 90 age group. In males, R strains (28%) were isolated, and in females, the highest MDR (24%) strains were found, with no significant gender differences. In sepsis diagnosis cases, the highest antimicrobial resistance (16%), MDR (16%), and XDR (8%) strains were isolated. The algD gene was detected in R strains (36%), while pelF (40%) and pslD (40%) were detected in MDR strains. Strong biofilm formation was found in MDR (20%) and XDR (12%) strains, and moderate biofilm formation was observed in R strains (28%).

Overall, the study found an association between biofilm formation and MDR/XDR strains. This suggests that the highest biofilm formation and percentage of pelF and pslD gene detection in MDR strains may contribute to the persistence and severity of infections caused by these strains.

Uropathogenic Escherichia coli (UPEC) is a leading cause of urinary tract infections, which are a significant public health concern worldwide. Antibiotic resistance among UPEC isolates is an increasing challenge, necessitating a better understanding of the resistance patterns and underlying genetic mechanisms. This study examined the prevalence of antibiotic resistance phenotypes and the detection of specific resistance genes among patients with UPEC infections in Sheikh Ragheb Harb University Hospital in south Lebanon.

Antimicrobial resistance phenotype of 104 urine samples was tested to determine the resistance percentages for various antibiotics including ampicillin, gentamicin, ciprofloxacin, tetracycline, bactrim, meropenem, and imipenem using disk diffusion test. Additionally, molecular analysis like polymerase chain reaction (PCR) was performed to detect the presence of blaSHV, qnrA, tetA, dfrA1, aac3, blaOXA and blaIMP resistance genes.

The antimicrobial resistance testing revealed the following resistance percentages for various antibiotics: ampicillin (100%), gentamicin (15.38%), ciprofloxacin (34.61%), tetracycline (48.07%), bactrim (17.3%), meropenem (0.96%) and imipenem (0.96%). The analysis of resistance genes showed the presence of blaSHV (7.96%), qnrA (0.96%), tetA (20.19%), and dfrA1 (0.96%) genes, while the aac3, blaOXA, and blaIMP genes were not detected.

The high rates of antibiotic resistance observed, particularly to ampicillin and tetracycline, highlight the need for more judicious antibiotic use and the development of alternative treatment strategies to combat UPEC infections. These results can inform antimicrobial stewardship programs and guide the selection of appropriate empiric therapy for urinary tract infections.

 In this research, a novel series of heterocyclic compounds containing pyrazoline nuclei was synthesized in two steps.

In the first step, chalcones were prepared using the Claisen-Schmidt reaction between substituted benzaldehydes and acetophenone derivatives. In the second step, the chalcones were cyclized under acidic conditions with hydrazine derivatives to produce pyrazolines. All compounds were characterized through physical, chromatographic, spectroscopic, and elemental analyses, and their antibacterial properties were tested using seven microorganisms. The minimum inhibitory concentrations of all compounds were determined using the broth dilution method.

Among them, compound 2f (4-(1, 5-diphenyl-4, 5-dihydro-1H-pyrazol-3-yl) phenol) exhibited the highest antibacterial and antifungal activity, making it the most potent compound in the series.

 These results indicate that increasing the polarity of the compounds enhanced their efficacy against Gram-positive strains, whereas derivatives containing at least one methoxy group in their structure suppressed Gram-negative growth.

Bacterial infection among neonatal patients admitted to the neonatal intensive care unit (NICU) is a global crisis and is among the first causes of neonatal mortality globally. Hence, this study aimed to evaluate the prevalence of bacterial pathogens from collected samples of neonatal infection in the NICU of a tertiary care center in Tehran, Iran.
In this study, we used data from blood, ulcer/fluids, and urine samples of NICU neonates at Imam Khomeini Hospital from 2019 to 2022.
Overall, 712 urine cultures (144 positives), 4578 blood cultures (376 positives), and 1771 ulcer/fluid cultures (411 positives) were gathered. Among positive blood cultures, the most prevalent bacterial species was Klebsiella pneumonia (120, 32.88%). Among urine cultures, the most prevalent bacterial species was Klebsiella pneumonia (71, 49.31%). Among positive ulcer/fluid cultures, the most prevalent bacterial species were Coagulase Negative Staphylococci (150, 36.49%). The highest sensitivity of Klebsiella pneumonia was against Ciprofloxacin (15.83%) in blood samples and resistant to Gentamycin (81.67%). Among urine samples, the highest sensitivity of Klebsiella pneumonia was against Ciprofloxacin (29.58%%) and the highest resistance against Gentamycin (84.51%). Among the ulcer/fluid samples, the highest sensitivity of Coagulase Negative Staphylococci was against Ciprofloxacin (13.48%) and the highest resistance against Cotrimoxazole (14.81%).
The most prevalent bacterial species found were Klebsiella pneumonia and Coagulase Negative Staphylococci. These species showed high resistance against multi drugs such as Cotrimoxazole, Ampicillin-sulbactam, and Piperacillin-tazobactam. National health policymakers should focus on surveillance programs to control and monitor such trends in antibiotic resistance.

Over recent decades, Acinetobacter baumannii has emerged as a significant cause of complicated nosocomial infections worldwide, largely due to its ability to harbor multiple antimicrobial resistance (AMR) genes, including metallo-β-lactamases (MBLs) and extended-spectrum β-lactamases (ESBLs). This situation is particularly concerning for patients in intensive care units (ICUs), who are at greater risk for such infections. This cross-sectional study aims to investigate the antimicrobial resistance of A. baumannii in ICUs, with a specific focus on resistance associated with ESBL genes, including blaCTX-M, blaGES, and blaIMP.
Samples were collected from ICUs at Rasool-E-Akram General Hospital in Tehran, Iran. Following standard identification procedures, one hundred A. baumannii isolates were confirmed using specific primers for the blaOXA-51 gene. Antibiotic susceptibility testing (AST) was performed, and the phenotypic production of ESBLs was assessed using the double-disk synergy test (DDST). The prevalence of the blaCTX-M and blaGES ESBL genes, as well as the blaIMP MBL gene, was determined through polymerase chain reaction (PCR).
The isolates exhibited similarly high resistance rates to cefotaxime (98%) and ciprofloxacin (98%). Seven isolates were found to be resistant to colistin, while only two isolates were identified as phenotypic ESBL producers. Among the 100 isolates tested, the prevalence rates for blaCTX-M and blaGES were 25% and 2%, respectively, with no detection of blaIMP.
Our findings reinforce the growing concern regarding antibiotic resistance in A. baumannii, particularly within clinical environments. To address the dissemination of this highly resistant pathogen, it is imperative that effective surveillance strategies be implemented in hospitals, especially within ICUs, to optimize antibiotic usage.

Antimicrobial resistance (AMR) has been a concerning public health issue even before the coronavirus disease 2019 (COVID-19) outbreak. However, the impact of the COVID-19 pandemic on AMR has not been comprehensively investigated.

The main objective of this study was to investigate the patterns of AMR before, during, and after the COVID-19 pandemic.

Data from hospital records of cancer patients in the hematology ward were obtained for this cross-sectional study using a census sampling method from January 2018 to July 2023. Clinical specimens were collected, including urine, stool, cerebrospinal fluid, ascites, pleural fluid, oropharynx, blood, and synovial fluid. All specimens were sent to the central laboratory of the hospital. The obtained samples were cultured on blood agar (Merck) and MacConkey agar (Merck) media and incubated for 24 hours. The classification of strains as resistant, intermediate, or susceptible was determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.

In the present study, 382 isolates were obtained from 186 (48.7%) males and 196 (51.3%) females admitted to the hematology ward at Taleqani Hospital. Among the 382 isolates, 102 were Escherichia coli , 97 were Klebsiella pneumoniae , 51 were Pseudomonas aeruginosa , 49 were coagulase-negative Staphylococcus , 30 were S. aureus , and 53 were other species. There was a changing trend in the antibiotic susceptibility patterns of ceftazidime for coagulase-negative Staphylococcus , as well as in multiple agents including meropenem, amikacin, and piperacillin-tazobactam for P. aeruginosa . For K. pneumoniae , there was a significant change in the antibiotic susceptibility patterns for amikacin, piperacillin, and ceftriaxone. For S. aureus , a significant difference was observed in the antibiotic susceptibility patterns of meropenem and clindamycin. For E. coli , significant differences were found in antibiotic susceptibility patterns for imipenem, amikacin, and cefazolin.

Although we have navigated through the COVID-19 pandemic, its consequences, such as altered trends in AMR, continue to pose challenges to the healthcare system. Coronavirus disease 2019has influenced the resistance patterns of both gram-negative and gram-positive bacteria. Monitoring adherence to guidelines is crucial to prevent further spread of resistant strains, particularly in developing countries where improvements in attitudes toward antibiotic prescription and hygiene standards are needed.

Urinary tract infections are one of the world's major health problems. In addition, clinical disorders may result from the presence of bacteria or fungi in urine. The aim of this study was to isolate Escherichia coli (E. coli) strains from midstream urine samples, and to determine molecular characterization of encoded Extended Spectrum Beta-Lactamase (ESBL) genes.

Collected urine samples were streaked on MacConkey, blood and EMB agar plates, then identifying E. coli isolates by using antibiotic susceptibility tests. ESBL production was measured using double disc diffusion. Furthermore, uniplex PCR was performed to identify two ESBL genes (blaCTX and blaTEM).

Among 412 isolates, 198 (48.1%) were E. coli strains, followed by Staphylococcus saprophyticus, Klebsiella sp., Serratia sp., Enterococci sp. and Proteus sp. with frequency of 132 (32.0%), 51 (12.4%), 15 (3.6%), 10 (2.4%), and 6 (1.5%) respectively. Female participants who were between the ages of 40 and 49 years old, married, and pregnant were more likely to develop urinary tract infections (UTIs). E. coli species were present in 189 (95.5) of the recurrent UTIs. Regarding antimicrobial susceptibility testing of E. coli isolates, the highest percentage of resistance and susceptible rates were found for nalidixic acid (75.8%) and gentamicin (64.1%) respectively. Among the E. coli isolates, 25 (12.6%) were ESBL-producers. The blaCTX-M gene was genetically confirmed in 20 (10.1%) of the isolates.

E. coli is the most common cause of UTI and ESBL production leads to increased resistance to common antibiotics and complicates treatment strategies.

Septic arthritis (SA) is an orthopedic emergency mainly caused by bacteria. SA due to Escherichia coli (E. coli) is rare with a poor prognosis. This study aimed to assess the occurrence and antibiotic resistance patterns of E. coli in SA patients in Quetta, Balochistan, Pakistan.

A cross-sectional study was conducted from March 2021 to December 2023. 220 samples were collected from SA patients from tertiary care hospitals. Joint aspirates (2ml) and blood (5ml) were analyzed for microbial and hematological examination.

There were 5.45% samples positive, and 94.5% negative for E. coli. SA due to E. coli was more common in male (6.2%) than female (4.6%) patients with the knee being the most affected joint (6.3%). E. coli was more common in patients aged 41-60 years (7.7%), lower socioeconomic (6.9%), and illiterate (8.6%) patients. Suspected patients showed a significant increase in the levels of white blood cells (WBC), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), notably, these levels were further elevated in E. coli-positive patients. The polymerase chain reaction (PCR) based identification of E. coli showed clear bands of 204bp of the 16S rRNA gene. Sequence analysis using the Basic Local Alignment Search Tool found high similarity with pathogenic E. coli from Egypt and China. The identified E. coli strain showed significant resistance to common antibiotics: amoxicillin, amoxicillin-clavulanate, ceftriaxone, sulfamethoxazole/trimethoprim, gentamicin, tetracycline, and erythromycin.

Antibiotic resistance in E. coli from SA patients suggests the need for accurate antibiotic selection to ensure prompt treatment.