Evaluating the antimicrobial resistance patterns among major bacterial pathogens isolated from clinical specimens taken from patients in Mofid Children's Hospital, Tehran, Iran: 2013-2018

Heterocyclic-Based Analogues against Sarcine-Ricin Loop RNA from Escherichia coli: In Silico Molecular Docking Study and Machine Learning Classifiers

BACKGROUND

Heterocyclic-based drugs have strong bioactivities, are active pharmacophores, and are used to design several antibacterial drugs. Due to the diverse biodynamic properties of well-known heterocyclic cores, such as quinoline, indole, and its derivatives, they have a special place in the chemistry of nitrogen-containing heterocyclic molecules.

OBJECTIVES

The objective of this study is to analyze the interaction of several heterocyclic molecules using molecular docking and machine learning approaches to find out the possible antibacterial drugs.

METHODS

The molecular docking analysis of heterocyclic-based analogues against the sarcin-Ricin Loop RNA from E. coli with a C2667-2'-OCF3 modification (PDB ID: 6ZYB) is discussed.

RESULTS

Many heterocyclic-based derivatives show several residual interaction, affinity, and hydrogen bonding with sarcin-Ricin Loop RNA from E. coli with a C2667-2'-OCF3 alteration which are identified by the investigation of in silico molecular docking analysis of such heterocyclic derivatives.

CONCLUSION

The dataset from the molecular docking study was used for additional optimum analysis, and the molecular descriptors were classified using a variety of machine learning classifiers, including the GB Classifier, CB Classifier, RF Classifier, SV Classifier, KNN Classifier, and Voting Classifier. The research presented here showed that heterocyclic derivatives may operate as potent antibacterial agents when combined with other compounds to produce highly efficient antibacterial agents.

Serotyping and molecular profiles of virulence-associated genes among Klebsiella pneumoniae isolates from teaching hospitals of Ardabil, Iran: A cross-sectional study

Background and Aims

Klebsiella pneumoniae is a Gram-negative bacterium that colonized various organs. This bacterium is associated with different community-acquired and hospital-acquired infections. The present study aims to assess the capsular serotypes and frequency of virulence-associated genes in K. pneumoniae isolates from teaching hospitals in Ardabil, Iran.

Methods

From October 1, 2019, to November 31, 2021, different clinical samples were collected and K. pneumoniae isolates were diagnosed using conventional biochemical tests. The final identification of K. pneumoniae was performed through the polymerase chain reaction (PCR) method using a specific primer targeting the khe gene. The PCR method was employed to confirm the presence of virulence-associated genes and aerobactin, and the main capsular serotypes based on the specific primers.

Results

Of all 100 K. pneumoniae isolates, 4% and 2% were typeable with K5 and K2 primers, respectively. In addition, entB (94%), fimH (91%), and wcaG (87%) had the highest frequency among the virulence-associated genes. 24% of K. pneumoniae isolates harbored the entB-wcaG-fimH genes simultaneously. Moreover, 50% of capsular serotype 5 harbored the ybts-mrkD-entB-wcaG-fimH genes simultaneously.

Conclusion

The findings revealed that 6% of all K. pneumoniae isolates were typeable, distributed in the two serotypes K5 and K2. Most K. pneumoniae isolates were positive for multiple types of virulence genes. Identifying bacterial virulence genes aids in molecular detection, assay development, and therapeutic pathways.

Bacterial Species and Antibiotic Resistance-A Retrospective Analysis of Bacterial Cultures in a Pediatric Hospital

Antimicrobial resistance (AMR) has become a major healthcare concern having a rising incidence, especially in pediatric patients who are more susceptible to infections. The aim of our study was to analyze the bacterial species isolated from patients admitted to our tertiary hospital and their AMR profiles. We conducted a retrospective observational study by examining the bacterial cultures collected from pediatric patients admitted to our hospital over a period of one year. We identified the most common bacterial species from 1445 clinical isolates and their AMR patterns using standard microbiological techniques. Our analysis revealed that the most frequently isolated bacterial species were Escherichia coli (23.73%), Staphylococcus aureus (15.64%), Klebsiella species (12.04%), and Pseudomonas species (9.96%). Additionally, these species exhibited varying levels of resistance to commonly used antibiotics. Notably, we observed high rates of resistance among Gram-negative bacteria, including extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species. Among Gram-positive bacteria, we observed a high level of methicillin-resistant Staphylococcus aureus. Our findings highlight the urgent need for effective antibiotic management programs and infection control measures to address the rising incidence of AMR in pediatric hospitals. Further research is needed to identify the mechanisms of resistance in these bacterial species and to develop new strategies for preventing and treating infections caused by antibiotic-resistant bacteria in pediatric patients.

Prevalence of multidrug-resistant and extensively drug-resistant phenotypes of Gram-negative bacilli isolated in clinical specimens at Centre Hospitalo-Universitaire Ibn Rochd, Morocco

Introduction

antimicrobial resistance in gram-negative bacilli is one of the major concerns in public health. We aimed to evaluate gram-negative bacilli epidemiology, antimicrobial profiles, and the resistance´s mechanism for Enterobacteriaceae isolated from specimens of hospitalized patients in wards of University Hospital Center Ibn Rochd of Casablanca, Morocco.

Methods

a prospective study of the patient's specimens, collected from December 2016 to 31st March 2017. Isolation and identification were performed using conventional biochemical tests. According to the European Committee on Antimicrobial Susceptibility Testing guidelines, antibiotic susceptibility was determined. Polymerase Chain Reaction (PCR) was used to detect β-lactamase and carabapenemase genes: CTX-M, SHV, TEM, OXA-48, NDM, and VIM among the Enterobacteriaceae.

Results

according to inclusion criteria, 38 Enterobacteriaceae, 25 Acinetobacter baumannii (A. baumannii), and 10 Pseudomonas aeruginosa (P. aeruginosa) were included during the study period; these bacteria were mainly responsible for bacteremia. Fifty-five percent of enterobacteria were extended-spectrum β-lactamase (ESBL), 42% EBSL and carbapenemase, and 3% carbapenemase, with high coresistances. Eighty-four percent of A. baumannii were XDR. All P. aeruginosa were MDR; amikacin showed the best activity (70% susceptibility). The genotypic approach revealed the presence of blaCTX-M, blaSHV, blaTEM in 68%, 22%, and 11% respectively. Of the 22 carbapenemase-producers, 41% were blaOXA-48 and 18% blaNDM; none had blaVIM. Furthermore, various genes coexistence were detected: blaCTX-M+blaOXA-48; blaCTX-M+blaNDM; blaCTX-M+blaSHV+blaOXA-48; and blaSHV+blaOXA-48.

Conclusion

findings revealed highly resistance rate among isolates. This raises the need to control antibiotics and regular screening to identify dynamics promoting resistance. Thus, we recommend developing antimicrobial stewardship programs and improving hygiene systems to prevent the nosocomial spreading of these phenotypes in our center.

In vitro and in vivo antibiofilm activity of the synthetic antimicrobial peptide WLBU2 against multiple drug resistant Pseudomonas aeruginosa strains

BACKGROUND

The global crisis of antibiotic resistance increases the demand for the novel promising alternative drugs such as antimicrobial peptides (AMPs). Here, the antibiofilm activity of the WLBU2 peptide against Pseudomonas aeruginosa (P. aeruginosa) isolates was investigated in this study.

METHODS

Two clinical MDR and carbapenem resistant P. aeruginosa (CRPA) isolates, and standard P. aeruginosa ATCC 27,853 were investigated. The MIC and MBC of WLBU2 were determined. The MBIC was determined to evaluate inhibitory activity of WLBU2 on biofilm formation and MBEC to dispersal activity on preformed biofilm. The relative expression levels of biofilm-associated genes including rhlI, rhlR, lasI and lasR were analyzed using RT-qPCR. In vivo evaluation of inhibitory effect of WLBU2 on biofilm formation was performed in the murine models of P. aeruginosa biofilm-associated subcutaneous catheter infection.

RESULTS

MIC and MBC of WLBU2 for both MDR and ATCC 27,853 P. aeruginosa strains were 8 and 16 µg/mL, respectively, while both the MIC and MBC against the CR strain were 4 µg/mL. MBIC was estimated to be 64 µg/ml for all strains. MBEC against MDR and ATCC 27,853- P. aeruginosa strains was 128 µg/ml and against CRPA was 64 µg/ml. The bacterial adhesion to a static abiotic solid surface (the surface in the polypropylene microtiter wells) was significantly inhibited at 1/4× MIC in all P. aeruginosa strains and at 1/8× MIC in CRPA strain (P < 0.05). Following treatment with WLBU2 at 1/8× MIC, significant inhibition in biofilm formation was observed in all isolates (P < 0.05). Results of the colorimetric assay showed that WLBU2 at 4× MIC was able to disperse 69.7% and 81.3% of pre-formed biofilms on abiotic surface produced by MDR and standard (ATCC 27,853) P. aeruginosa, respectively (P < 0.03), while a 92.2% reduction in the CRPA biofilm was observed after treatment with 4× MIC WLBU2 (P < 0.03). The expression levels of all genes in isolates treated with 1/2 MIC of WLBU2 were down-regulated by more than four-fold compared to the untreated isolates (P < 0.05). WLBU2 significantly inhibited biofilm formation in murine catheter-associated CRPA infection model at 1/4×MIC, 1/2×MIC, and 1×MIC by 33%, 52%, and 67%, respectively.

CONCLUSION

Considering relatively strong inhibitory and eradication potency of WLBU2 on the P. aeruginosa biofilms in in vitro and in vivo conditions, the peptide can be considered as a promising candidate for designing an antibiofilm drug.

Molecular evaluation of aminoglycosides resistance and biofilm formation in Klebsiella pneumoniae clinical isolates: A cross-sectional study

Background and Aims

Resistance to antibiotics and the capability to develop biofilm as two main virulent determinants of Klebsiella pneumoniae have important role in infection persistence. The aim of the study was to evaluate the association between the prevalence of aminoglycoside resistance and virulence genes and biofilm formation capacity in K. pneumoniae strains isolated from hospitalized patients in South-West of Iran.

Methods

A total of 114 non-duplicate clinical isolates of K. pneumoniae collected from Ahvaz teaching hospitals. Identification of species was performed by biochemical tests and then confirmed by polymerase chain reaction (PCR) of rpoB gene. The susceptibility to antibiotics was determined by Kirby-Bauer disk diffusion method. Biofilm formation was assessed by microtiter plate method. Finally, PCR was conducted to detect virulence gene determinants including fimbrial genes, aminoglycoside modifying enzymes- and 16S rRNA methylase (RMTase) genes.

Results

Totally, all collected strains were carbapenem resistant and showed multidrug- and extensively drug-resistance phenotype (75% and 25%, respectively). Seventy-one percent (n = 81) of isolates were non-susceptible to aminoglycosides. Among aminoglycoside antibiotics, K. pneumoniae isolates showed the highest and lowest resistance rates to tobramycin (71%) and the amikacin (25%), respectively. All biofilm producer strains were positive for the presence virulence determinants including ecpA, fimA, mrkD, and mrkA. Of 81 aminoglycosides non-susceptible isolates 33% were positive for the presence ant (2″)-Ia as the most prevalent gene followed by aac (3')-IIa and armA (27%), aac (6')-Ib (18%), and aph (3')-Ia (15%).

Conclusion

K. pneumoniae isolates showed the highest and the lowest aminoglycoside resistance rates to tobramycin and amikacin, respectively. Majority of isolates were biofilm producers and there was significant association between antibiotic resistance pattern and the strength of biofilm production. The ant(2″)-Ia, aac (3')-IIa, and armA genes in aminoglycoside-resistant isolates.

Antibiotic Susceptibility Patterns for Carbapenem-Resistant Enterobacteriaceae

Carbapenem is a broad-spectrum beta-lactam antibiotic considered the last choice for the treatment of antibiotic-resistant Gram-negative bacteria. Thus, the increasing rate of carbapenem resistance (CR) in Enterobacteriaceae is an urgent public health threat. This study aimed to evaluate the antibiotic susceptibility pattern of carbapenem-resistant Enterobacteriaceae (CRE) to new and old antibiotics. In this study, Klebsiella pneumoniae, E. coli, and Enterobacter spp. were collected from 10 hospitals in Iran for one year. CRE is recognized by resistance to meropenem and/or imipenem disk after identification of the collected bacteria. Antibiotic susceptibility of CRE against fosfomycin, rifampin, metronidazole, tigecycline, and aztreonam was detected by disk diffusion method and colistin by MIC. In this study, 1222 E. coli, 696 K. pneumoniae, and 621 Enterobacter spp. were collected from 10 hospitals in Iran in one year. Fifty-four E. coli (4.4%), 84 K. pneumoniae (12%), and 51 Enterobacter spp. (8.2%) were CRE. All CRE strains were resistant to metronidazole and rifampicin. Tigecycline has the highest sensitivity on CRE and levofloxacin for Enterobacter spp. Tigecycline showed an acceptable effectiveness rate of sensitivity on the CRE strain. Therefore, we suggest that clinicians consider this valuable antibiotic to treat CRE.

Molecular Detection and Characterization of the Staphylococcus epidermidis and Staphylococcus haemolyticus Isolated from Hospitalized Patients and Healthcare Workers in Iran

Background

The present study is aimed at surveying the antibiotics resistance profile, biofilm formation ability, staphylococcal cassette chromosome mec (SCCmec) types, and molecular epidemiology of Staphylococcus epidermidis and Staphylococcus haemolyticus isolated from hospitalized patients and healthcare workers in four teaching hospitals in Iran.

Methods

In total, 43 Staphylococcus epidermidis and 12 Staphylococcus haemolyticus were isolated from hospitalized patients, and 19 Staphylococcus epidermidis and 7 Staphylococcus haemolyticus isolated from healthcare workers were included in the present study. The antimicrobial resistance profile of isolates was determined using the disk diffusion method. Moreover, the resistance of isolates to methicillin was identified using the cefoxitin disk diffusion test. The microtiter-plate test was used for quantifying biofilm formation. Moreover, the frequency of icaA and icaD genes was determined using PCR assay. The molecular epidemiology of methicillin-resistant isolates was determined using SCCmec typing and pulsed-field gel electrophoresis methods.

Results

Among all coagulase-negative staphylococci isolates, the highest resistance rate (81.5%) was seen for cefoxitin and cotrimoxazole. All of the isolates were susceptible to linezolid. Out of the 66 mecA-positive isolates, the most common SCCmec type was the type I (n = 23; 34.8%) followed by type IV (n = 13; 19.7%). Using pulsed-field gel electrophoresis (PFGE) assay, 27 PFGE types including 14 common types and 13 singletons were obtained among 51 methicillin-resistant S. epidermidis (MRSE) isolates. Moreover, among 12 methicillin-resistant S. haemolyticus (MRSH) isolates, 8 PFGE types were detected, of which 5 PFGE types were singletons.

Conclusion

The high rate of resistance to antibiotics as well as the possibility of cross-infection shows the importance of a pattern shift in the management and controlling programs of coagulase-negative staphylococci, especially in healthcare centers. Clinical trial registration. The present study is not a clinical trial study. Thus, a registration number is not required.

The prevalence of clarithromycin-resistant Helicobacter pylori isolates: a systematic review and meta-analysis

Background

Knowledge of global clarithromycin (CLA)-resistant rates of Helicobacter pylori (H. pylori) is crucial for decision of the most appropriate eradication therapies with good clinical outcomes. Therefore, this review and meta-analysis aimed to evaluate the global prevalence of the CLA resistance in H. pylori to provide some guidance for selecting the first-line antibiotics.

Method

A comprehensive search was performed for relevant literature until April 2021 in PubMed, Embase, and Web of Science databases. Freeman-Tukey double arcsine transformation was performed to estimate the weighted pooled prevalence of resistance.

Results

The meta-analysis included 248 articles. The prevalence of CLA-resistant H. pylori was 27.53% (95% CI [25.41-29.69]). The heterogeneity between reports was significant (I² = 97.80%, P < 0.01). The resistance rate increased from 24.28% in 2010-2017 to 32.14% in 2018-2021 (P < 0.01). Iran, with 38 articles, has the most report. Nevertheless, Switzerland, Portugal, and Israel had the highest resistance rates (67.16%, 48.11%, and 46.12%, respectively). The heterogeneity between the continents and the antimicrobial susceptibility methods also interpreted standard guidelines and breakpoints was insignificant (P > 0.05).

Conclusion

Overall CLA resistance rate was 27.53%, worldwide. The difference in CLA resistance rate among the included studies can be due to several reasons such as differences in antibiotic prescription rates in various geographic areas, use of different breakpoints or inaccurate criteria in performed studies, and the emergence of multidrug-resistant (MDR) strains.

Antimicrobial Resistance Profile of Bacteria Causing Pediatric Infections at the University Teaching Hospital in Rwanda

Bacterial infections pose a global threat, especially in the pediatric population. Antimicrobials that are used to treat such infections continuously show reduced efficacy, and empirical therapy is a major treatment option in Rwanda. This study aimed to determine the resistance rate of commonly used antibiotics in pediatric patients. The study was conducted from June 1, 2018 to May 30, 2019, and microbiological samples were collected from 712 children with suspected bacterial infections. Antimicrobial sensitivity testing was performed on 177 positive cultures (24%) that were considered for data analysis. The findings show that the major bacterial isolates were Klebsiella pneumoniae (n = 50, 28.2%), Escherichia coli (n = 47, 26.5%), and Staphylococcus aureus (n = 38, 21.4%). In general, the greatest antibiotic resistance rate was observed in ampicillin (n = 125, 86.2%), amoxicillin-clavulanic acid (n = 84, 82.4%), amoxicillin (n = 64, 79%), cefadroxil (n = 83, 69.2%), tetracycline (n = 72, 59.7%), ceftazidime (n = 42, 55.3%), and cefuroxime (n = 14, 53.8%). More specifically, Klebsiella pneumoniae was 100% resistant to amoxicillin-clavulanic acid, cefuroxime, trimethoprim-sulfamethoxazole, ceftazidime, erythromycin, and clindamycin. Staphylococcus aureus was 86.7% resistant to ampicillin, and Escherichia coli was 91.7% resistant to tetracycline, 90.6% resistant to ampicillin, 83.3% resistant to amoxicillin-clavulanic acid, 79.3% resistant to cefadroxil, and 78.6% resistant to ceftazidime. Moreover, Klebsiella pneumoniae from blood and urine was 96.8% and 100% sensitive, respectively, to meropenem. Staphylococcus aureus from blood was 100% sensitive to vancomycin, whereas Escherichia coli from urine was sensitive to clindamycin (100%), nitrofurantoin (80.6%), and ciprofloxacin (72.7%). In conclusion, our findings show a high resistance rate to commonly used antibiotics, which suggests precaution in empirical therapy and continued surveillance of antimicrobial resistance.

Molecular detection and characterization of Shigella spp. harboring extended-spectrum β-lactamase genes in children with diarrhea in northwest Iran

Shigellosis is one of the acute bowel infections and remains a serious public health problem in resource-poor countries. The present study aimed to survey the distribution of extended-spectrum β-lactamase (ESBL)-producing Shigella strains isolated from patients with diarrhea in northwest Iran. In the present cross-sectional study, from January 2019 to December 2020, 1280 fecal samples were collected from children with diarrhea in Ardabil, Iran. Multiplex PCR assay was applied for the presence of ipaH, invC, wbgZ, rfpB, and rfc genes to detect Shigella spp., Shigella sonnei, Shigella dysenteriae, Shigella flexneri, and Shigella boydii, respectively. Phenotypic detection of ESBL-producing isolates was carried out using the Double Disc Test (DDT). The frequency of main ESBL encoding genes including bla_CTX-M, bla_SHV, and bla_TEM was detected using multiplex PCR. The genetic similarity of S. sonnei isolates was determined using ERIC PCR. A total of 49 Shigella isolates (3.8%; 49/1280) including 42 (85.7%) S. sonnei, 5 (10.2%) S. flexneri, and 2 (4%) S. dysenteriae were identified. S. boydii was not detected in any fecal samples. ESBLs were produced by 10.2% of Shigella spp. including 3 S. sonnei, 1 S. flexneri, and 1 S. dysenteriae. The ESBL encoding genes include bla_CTX-M and bla_TEM found in 65.3% and 61.2% of isolates, respectively. bla_SHV gene was not detected in any isolates. The ERIC-PCR profiles allowed the differentiation of 42 S. sonnei strains into 6 clusters. Our study revealed a high frequency of ESBL-encoding genes among Shigella spp. in northwest Iran. The high prevalence of S. sonnei harboring ESBL genes, in the present work, is the main challenge for dysentery treatment, and this concern justifies the need for effective and regular monitoring of antibiotic usage among patients.

Prevalence of ESBL-Producing Enterobacter Species Resistant to Carbapenems in Iran: A Systematic Review and Meta-Analysis

Background

Carbapenems are the last-line therapy for multidrug-resistant (MDR) infections caused by Enterobacterales, including those caused by Enterobacter species. However, the recent emergence of carbapenem-resistant (CR) and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae pathogens, which are resistant to nearly all antibiotics, has raised concerns among international healthcare organizations. Hence, because there is no comprehensive data in Iran, the current study aimed to evaluate the prevalence of antibiotic resistance among Enterobacter species, especially CR and ESBL-producing strains, in Iran.

Methods

The literature search was performed up to June 21, 2021, in national and international databases using MeSH-extracted keywords, i.e., Enterobacter, antibiotic resistance, carbapenem, ESBL, and Iran. Study selection was done based on the predefined inclusion and exclusion criteria, and data analysis was carried out using the Comprehensive Meta-Analysis (CMA) software.

Results

The pooled prevalence of Enterobacter species resistant to various antibiotics is as follows: imipenem 16.6%, meropenem 16.2%, aztreonam 40.9%, ciprofloxacin 35.3%, norfloxacin 31%, levofloxacin 48%, gentamicin 42.1%, amikacin 30.3%, tobramycin 37.2%, tetracycline 50.1%, chloramphenicol 25.7%, trimethoprim/sulfamethoxazole 52%, nalidixic acid 49.1%, nitrofurantoin 43%, ceftriaxone 49.3%, cefixime 52.4%, cefotaxime 52.7%, ceftazidime 47.9%, cefepime 43.6%, and ceftizoxime 45.5%. The prevalence rates of MDR and ESBL-producing Enterobacter species in Iran were 63.1% and 32.8%, respectively.

Conclusion

In accordance with the warning of international organizations, our results revealed a high prevalence of ESBL-producing Enterobacter species in Iran, which is probably associated with the high prevalence of Enterobacter species resistant to most of the assessed antibiotics, especially MDR strains. However, the resistance rate to carbapenems was relatively low, and these drugs can still be considered as drugs of choice for the treatment of Enterobacter infections in Iran. Nevertheless, continuous monitoring of drug resistance along with antibiotic therapy based on the local data and evaluation of the therapeutic efficacy of new antibiotics or combination therapeutic strategies, such as ceftazidime/avibactam, meropenem/vaborbactam, plazomicin, and eravacycline, is recommended.

Evaluation of the bioresistance profile of enterobacteria isolated from faeces of children with diarrhoea in the town of Koula-Moutou, Gabon: prospective study

INTRODUCTION

the emergence and expansion of multidrug resistance in Enterobacteriaceae responsible for various infections are increasing in the world. This study was designed to determine the phenotypic profiles of the resistance of enterobacteria strains isolated from the faeces of children with diarrhoeal diseases and to classify them according to the type of resistance.

METHODS

screening was carried out on 98 isolates divided into 2 groups: opportunistic pathogens and strict enteropathogens. Their sensitivity to 13 antibiotics was evaluated by the Mueller Hinton agar medium diffusion method.

RESULTS

a strong resistance to different classes of β-lactams was found in the strains, 74.0% (n=45) and 83.3% (n=31) for opportunists and enteropathogens, respectively. These strains were completely resistant to doxycycline and erythromycin (100%; n=98) for both types of bacteria. Opportunists and enteropathogens were 95.1% (n=58) and 94.6% (n=35) resistant to gentamicin, and 31.1% (n=19) and 35.1% (n=13) resistant to chloramphenicol, respectively. Similarly, the total resistance of strains was observed with ofloxacin and amounted to 98.4% (n=60) and 96.7% with levofloxacin and norfloxacin, respectively. The analysis of β-lactam resistance phenotypes revealed a dominance of the carbapenemase-producing strains (28.6%; n=28). However, 24.3% (n=9) of enteropathogens were pan-resistant versus 19.7% (n=12) for opportunists.

CONCLUSION

the results of this study indicate a worryingly high level of antibiotic resistance in enterobacteria which might tend towards total resistance.

Antibiotic Resistance during COVID-19: A Systematic Review

One of the public health issues faced worldwide is antibiotic resistance (AR). During the novel coronavirus (COVID-19) pandemic, AR has increased. Since some studies have stated AR has increased during the COVID-19 pandemic, and others have stated otherwise, this study aimed to explore this impact. Seven databases-PubMed, MEDLINE, EMBASE, Scopus, Cochrane, Web of Science, and CINAHL-were searched using related keywords to identify studies relevant to AR during COVID-19 published from December 2019 to May 2022, according to PRISMA guidelines. Twenty-three studies were included in this review, and the evidence showed that AR has increased during the COVID-19 pandemic. The most commonly reported resistant Gram-negative bacteria was Acinetobacterbaumannii, followed by Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa. A. baumannii and K. pneumonia were highly resistant to tested antibiotics compared with E. coli and P. aeruginosa. Moreover, K. pneumonia showed high resistance to colistin. Commonly reported Gram-positive bacteria were Staphylococcus aureus and Enterococcus faecium. The resistance of E. faecium to ampicillin, erythromycin, and Ciprofloxacin was high. Self-antibiotic medication, empirical antibiotic administration, and antibiotics prescribed by general practitioners were the risk factors of high levels of AR during COVID-19. Antibiotics' prescription should be strictly implemented, relying on the Antimicrobial Stewardship Program (ASP) and guidelines from the World Health Organization (WHO) or Ministry of Health (MOH).

Levofloxacin versus ceftriaxone and azithromycin for treating community-acquired pneumonia: a randomized clinical trial study

Background and Objectives

We compared two common antibiotic regimens for the treatment of mild to moderate CAP: levofloxacin versus β-lactam and macrolide combination; in terms of their efficacy and side effects.

Materials and Methods

Patients with mild to moderate CAP were randomized into two groups. Group I received a combination of 1 gram ceftriaxone daily and 500 mg azithromycin daily for 5-7 days. Group II received levofloxacin 750 mg daily for five days. The signs and symptoms, hospitalization length, and the side effects were investigated.

Results

There were 77 and 74 patients in groups I and II. The vital signs of group II were significantly better on the 3^rd day of admission, except for the temperature (P=0.09). The O₂ saturation of group II was markedly improved on the 5^th day of admission (P=0.0061). In terms of clinical symptoms and hospitalization length, group II was considerably better. However, the rate of side effects in both groups was similar (P=0.885).

Conclusion

Hospitalized patients with mild to moderate CAP might take more advantage of fluoroquinolone administration. It could improve the patients' signs and symptoms and reduce hospitalization length, compared with the combination of macrolide and cephalosporin, with the same rate of side effects.

Phenotypic and molecular characterization of extended-spectrum β-lactamase/AmpC- and carbapenemase-producing Klebsiella pneumoniae in Iran

BACKGROUND

The objective of the current study is to evaluate the phenotypic and molecular characterization of ESBL/AmpC- and carbapenemase-producing K. pneumoniae isolates in Iran.

METHODS

From October 2018 until the end of April 2020, different clinical samples were collected and K. pneumoniae isolates were identified using conventional biochemical tests and PCR assay. Antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method. Modified Hedge Test (MHT) was applied to the identification of carbapenemase-producing K. pneumoniae. ESBL and AmpC-producing K. pneumoniae were detected using Double Disc Test (DDT) and Disc Potentiation Test (DPT), respectively. The presence of carbapenemase, ESBL, and AmpC encoding genes was screened by Polymerase Chain Reaction (PCR) assay.

RESULTS

A total of 100 K. pneumoniae isolates were collected. K. pneumoniae isolates had the highest resistance rate to cefazolin (66%) and cefotaxime (66%). Meropenem and amikacin with sensitivity rates of 76% and 69% were the most effective antimicrobial agents on K. pneumoniae isolates. It was found that 12 (12%), 27 (27%), and 9 (9%) K. pneumoniae isolates were positive in MHT, DDT, and DPT tests, respectively. Among the carbapenemase-encoding genes, bla_OXA-48 (24%) and bla_IMP (13%) genes had the highest frequency, while bla_KPC and bla_GIM genes were not detected among K. pneumoniae isolates. bla_TEM (48%) and bla_CMY (8%) genes had the highest frequency among ESBL and AmpC β-lactamase-encoding genes, respectively.

CONCLUSIONS

It is vital to adopt effective control strategies for K. pneumoniae infections and ensure rapid identification of antibiotic resistance profile.

Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options

Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.

Evaluation of phenotypic and genotypic patterns of aminoglycoside resistance in the Gram-negative bacteria isolates collected from pediatric and general hospitals

The purpose of the current study was to evaluate the phenotypic and genotypic patterns of aminoglycoside resistance among the Gram-negative bacteria (GNB) isolates collected from pediatric and general hospitals in Iran. A total of 836 clinical isolates of GNB were collected from pediatric and general hospitals from January 2018 to the end of December 2019. The identification of bacterial isolates was performed by conventional biochemical tests. Susceptibility to aminoglycosides was evaluated by the disk diffusion method (DDM). The frequency of genes encoding aminoglycoside-modifying enzymes (AMEs) was screened by the PCR method via specific primers. Among all pediatric and general hospitals, the predominant GNB isolates were Acinetobacter spp. (n = 327) and Escherichia coli (n = 144). However, E. coli (n = 20/144; 13.9%) had the highest frequency in clinical samples collected from pediatrics. The DDM results showed that 64.3% of all GNB were resistant to all of the tested aminoglycoside agents. Acinetobacter spp. and Klebsiella pneumoniae with 93.6%, Pseudomonas aeruginosa with 93.4%, and Enterobacter spp. with 86.5% exhibited very high levels of resistance to gentamicin. Amikacin was the most effective antibiotic against E. coli isolates. In total, the results showed that the aac (6')-Ib gene with 59% had the highest frequency among genes encoding AMEs in GNB. The frequency of the surveyed aminoglycoside-modifying enzyme genes among all GNB was found as follows: aph (3')-VIe (48.7%), aadA15 (38.6%), aph (3')-Ia (31.3%), aph (3')-II (14.4%), and aph (6) (2.6%). The obtained data demonstrated that the phenotypic and genotypic aminoglycoside resistance among GNB was quite high and it is possible that the resistance genes may frequently spread among clinical isolates of GNB.

Bacteriophages PɸEn-CL and PɸEn-HO can eliminate MDR Enterobacter cloacae and Enterobacter hormaechei isolated from burn wound infections without toxicity for human skin cells

The prevalence of multidrug-resistant (MDR) strains has caused serious problems in the treatment of burn infections. MDR Enterobactercloacae and Enterobacterhormaechei have been defined as the causative agents of nosocomial infections in burn patients. In this situation, examination of phages side effects on human cell lines before any investigation on human or animal that can provide beneficial information about the safety of isolated phages. The aim of this study was to isolate and identify the specific bacteriophages on MDR E. cloacae and E. hormaechei isolated from burn wounds and to analyze the efficacy, cell viability and cell cytotoxicity of phages on A-375 and HFSF-PI cell lines by MTT (3-(4, 5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide) colorimetric assay and lactate dehydrogenase (LDH) release assay. Phages were isolated from urban sewage Isfahan, Iran. Enterobactercloacae strain Iau-EC100 (GenBank accession number: MZ314381) and E. hormaechei strain Iau-EHO100 (GenBank accession number: MZ348826) were sensitive to the isolated phages. Transmission electron microscopy (TEM) results revealed that PɸEn-CL and PɸEn-HO that were described had the morphologies of Myovirus and Inovirus, respectively. Overall, MTT and LDH assays showed moderate to excellent correlation in the evaluation of cytotoxicity of isolated phages. The results of MTT and LDH assays showed that, phages PɸEn-CL and PɸEn-HO had no significant toxicity effect on A375 and HFSF-PI 3 cells. Phage PɸEn-HO had a better efficacy on the two tested cell lines than other phage. Our results indicated that, there were significant differences between the two cytotoxicity assays in phage treatment compared to control.

Study of aerobic and anaerobic bacterial profile of nosocomial infections and their antibiotic resistance in a referral center, Southwest Iran: A three year cross-sectional study

BACKGROUND

The drug resistance is expected to be the most important challenge in infection control in Iran, where there is no local report or standard drug resistance monitoring system. Therefore, this study aimed to investigate the aerobic and anaerobic bacterial profile of nosocomial infections and their antibiotic resistance in Ahvaz, southwest Iran.

METHODOLOGY

The gram-positive and gram-negative bacteria were identified on the basis of conventional culture and biochemical tests. The antibiotic resistance of the bacterial isolates against antibiotics was determined by the disk diffusion method.

RESULTS

Among total 1156 collected positive samples, E. coli and coagulase-negative staphylococci (CoNS) were the most frequent pathogenic gram negative bacteria (GNB) and gram positive bacteria (GPB) respectively. Drug susceptibility testing revealed that among GNB, P. aeruginosa was 100% resistant to amikacin, cefepime, ciprofloxacin and tetracycline. In the case of E. coli, the resistance rate was (98%) for trimethoprim sulfamethoxazole and cefepime. For GPB, S. aureus showed the highest resistance rates to amikacin (100%) and clindamycin (100%). In addition, CoNS strains showed a high level of resistance to doxycycline (100%), erythromycin (100%) and cefoxitin (97%). In Bacteroeides fragilis isolates, the highest resistance rate belonged to clindamycin (72%), and Clostridium perfringens strains showed high level of resistance to penicillin (46%).

CONCLUSION

The results highlighted that there are distinct factors leading to antimicrobial resistance in Ahvaz, southwest Iran. The primary contributors to the resistance development, include poor surveillance of drug-resistant infections, poor quality of available antibiotics, clinical misuse, and the ease of access to antibiotics. Moreover, similar factors such as self-medication and the lack of regulation on medication imports play a role in antibiotic resistance in the region.

Antibiotic Susceptibility, Biofilm Production, and Detection of mecA Gene among Staphylococcus aureus Isolates from Different Clinical Specimens

The increasing incidence of methicillin-resistant and biofilm-forming S. aureus isolates in hospital settings is a gruesome concern today. The main objectives of this study were to determine the burden of S. aureus in clinical samples, assess their antibiotic susceptibility pattern and detect biofilm formation and mecA gene in them. A total of 1968 different clinical specimens were processed to isolate S. aureus following standard microbiological procedures. Antibiotic susceptibility test of the isolates was performed by Kirby–Bauer disc-diffusion method following CLSI guidelines. Biofilm was detected through tissue culture plate method. Methicillin-resistant S. aureus (MRSA) isolates were screened using cefoxitin (30 µg) discs and mecA gene was amplified by conventional polymerase chain reaction (PCR). Of 177 bacterial growth, the prevalence of S. aureus was 15.3% (n = 27). MRSA were 55.6% (15/27) and 44% (12/27) exhibited multidrug resistance (MDR). There was no significant association between methicillin resistance and MDR (p > 0.05). Both MRSA and MSSA were least sensitive to penicillin (100%, 75%) followed by erythromycin (86.6%, 66.6%). Most of the MRSA (93.4%) were susceptible to tetracycline. All S. aureus isolates were biofilm producers—19 (70%) were weak and only one (4%) was a strong biofilm producer. The strong biofilm-producing MSSA was resistant to most of the antibiotics except cefoxitin and clindamycin. None of the MSSA possessed mecA gene while 8 (53.3%) MRSA had it. More than half of S. aureus isolated were MRSA. High incidence of multidrug resistance along with capacity to form biofilm among clinical isolates of S.aureus is a matter of apprehension and prompt adoption of biosafety measures is suggested to curb their dissemination in the hospital environments.

Antibiotic Resistance Pattern of Acinetobacter baumannii Strains: A Retrospective Study from Oman

Background:

Multidrug-resistant (MDR) Acinetobacter baumannii is of serious health concern and associated with high mortality. Data regarding the antibiotic resistance pattern of A. baumannii strains in Oman is limited.

Objectives:

To determine the antibiotic resistance pattern of A. baumannii from various clinical samples in a tertiary care hospital in the North-Batinah region of Oman.

Methods:

A. baumannii isolates recovered from various clinical samples in the Microbiology laboratory of Sohar Hospital, Oman, during 2015–2019 were retrospectively analyzed. Organism identification and their antibiotic resistance patterns were performed as recommended by the Clinical and Laboratory Standards Institute.

Results:

A total of 1890 A. baumannii nonduplicate isolates were found from clinical samples of 1326 patients. The isolates were more frequently isolated from elderly patients (40%) and in-patient department patients (67%). Infection/colonization was more common among patients treated in the medicine, intensive-care unit, and surgery departments. A. baumannii strains were highly resistant (50-83%) to most of the tested antibiotics, with the highest against ceftriaxone (83%) and ceftazidime (75%), and lowest against colistin (1%) and tigecycline (8%). Among the isolates, 67% (1265) were MDR strains. Of these, 22%, 32% and 16% were resistant to all six, five and four classes of the tested antibiotics.

Conclusion:

The study found that the frequency of isolation of MDR A. baumannii isolates in the northern region of Oman is high.

Molecular Detection of Carbapenemases and Extended-Spectrum β-Lactamases-Encoding Genes in Clinical Isolates of Pseudomonas aeruginosa in Iran

Background: Pseudomonas aeruginosa is a unique Gram-negative opportunistic pathogen that is the leading cause of nosocomial infections. Objectives: This study aimed to investigate the prevalence of the main carbapenemase and extended-spectrum β-lactamases encoding genes in P. aeruginosa clinical isolates. Methods: In the present study, we collected 85 P. aeruginosa clinical isolates from different wards of three military hospitals in Tehran, Iran. We used disk diffusion and agar dilution methods to determine resistance to 12 different antibiotics in these isolates. Also, we assessed the blaIMP, blaVIM, blaSHV, blaTEM, and blaCTX genes by polymerase chain reaction methods among all isolates. Results: Our results revealed that all isolates were resistant to two antibiotics, and 76 (89.4%) of isolates were multidrug-resistant. We observed maximum and minimum resistance rates against ticarcillin (n = 77; 90.5%) and colistin (n = 7; 8.2%), respectively. The blaVIM, blaIPM, blaTEM, blaSHV, and blaCTX genes were harbored by 44 (51.8%), 20 (23.5%), 41 (48.2%), 24 (28.2%), and 16 (18.8%) isolates, respectively. Conclusions: The resistance rate among P. aeruginosa strains is significantly increasing that causes nosocomial infections due to different mechanisms, including the high frequency of metallo-β-lactamases and extended-spectrum β-lactamases genes.

A decade of trends in the distribution and antimicrobial susceptibility of prevalent uropathogens among pediatric patients from Tehran, Iran during 2005-2016

Objectives

To determine changes in the distribution of uropathogens and their antimicrobial resistance in pediatric patients in a children's hospital from 2005 to 2016.

Methods

A cross-sectional analysis of uropathogens and their antimicrobial resistance within inpatient children was performed over the 11-year period, 2005 to 2016, in Ali Asghar children's hospital. The rate of antibiotic resistance among patients was evaluated according to demographic data including age, sex, urinary tract abnormities and history of antibiotic consumption.

Results

In total, 958 female and 349 male positive cultures were analyzed. Escherichia coli (E. coli) (77.6%) was the most common causative agent of urinary tract infection (UTI) in children and Klebsiella pneumoniae (10.4%), Pseudomonas aeruginosa (2.4%), and Enterococcus spp (2.4%) were less frequent isolated bacteria. The resistance rates of E. coli isolates were increased against amikacin, ceftriaxone, ceftazidime, ciprofloxacin, cotrimoxazole and imipenem from 2005 to 2010. However, we observed a decreasing trend for some of antibiotics including amikacin, gentamicin, imipenem, ceftazidime and cotrimoxazole during 2014–2016. The rate of antibiotic resistance was greater in boys than in girls against many antibiotics. The rate of resistance to amikacin, gentamicin, nitrofurantoin and cotrimoxazole in patients aged <1 year was higher than other age groups (p<0.001). A higher antibiotic resistance rate was observed in patients with anatomical abnormality and those who have had a history of antibiotic consumption.

Conclusion

The study indicated the significant decrease in E. coli antibiotic resistance in the last 3 years. An effective empirical treatment regime should be based on local epidemiology and antimicrobial susceptibility testing.

Frequency and co-colonization of vancomycin-resistant Enterococci and Candida in ICU-hospitalized children

In the time span between January 2018 and September 2020, 205 patients were enrolled in a prospective cohort study at Mofid Children's Hospital. Demographic information and clinical data on all the participating children were collected and rectal swabs were performed for the sampling method. All samples were analysed so as to identify the presence of Enterococcus and Candida colonization by the use of conventional biochemical tests. Resistance to vancomycin in Enterococcus isolates was phenotypically identified using an E-test kit and MIC value, interpreted according to the CLSI criteria. The presence of vanA and vanB genes, which encode the resistance to vancomycin, was screened by PCR assay. Candida species were detected in 21.5% of rectal swab samples. Candida glabrata (56.8%) and Candida albicans (43.2%) were the only Candida species detected. Enterococcus species were detected in 29.3% of rectal swab samples. Out of 60 Enterococcus isolates, 33 (55%) were resistant to vancomycin. Moreover, vanA was detected in 84.8% and vanB was detected in 3% of the 33 vancomycin-resistant Enterococcus isolates. Enterococcus and Candida species were frequently detected in the <1 year and 1–3 years age groups, respectively. Central venous access catheter and brain tumour were the main reasons for hospital admissions, 32.2% and 20.1% of total admissions, respectively. Furthermore, it must be noted that the most frequent underlying medical conditions in participating patients were esophageal atresia and hydrocephalus. The results of the present study demonstrated the necessity of determining the susceptibility of Enterococcus isolates to vancomycin before prescribing antibiotics.

Multicentre study of the main carbapenem resistance mechanisms in important members of the Enterobacteriaceae family in Iran

Resistance to carbapenems has been increasingly reported from the Enterobacteriaceae family, with different mechanisms in different geographic parts of the world. This study investigated the mechanisms of carbapenem resistance in Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. carried out as a multicentre study (n = 10). All third-generation cephalosporin-resistant E. coli, K. pneumoniae and Enterobacter spp. that had been recovered from the selected provinces were included. Modified Hodge test and Carba NP test were done as a phenotypical method for detection of carbapenemase; the most common carbapenemase was detected by PCR. We evaluated the presence of an active efflux pump by using cyanide 3-chlorophenylhydrazone. Overexpression of AcrA/B and presence of OqxAB was detected by real-time PCR and conventional PCR respectively. Microorganisms in this study included 58 E. coli, 95 K. pneumoniae and 60 Enterobacter spp. Modified Hodge test showed a sensitivity of 41% and a specificity of 83%, and the Carba NP test showed a sensitivity of 26% and a specificity of 92% for detection of carbapenemase. OXA-48 was the most frequently detected carbapenemase, followed by NDM-1. Thirty-nine percent and 27% of positive cyanide 3-chlorophenylhydrazone test organisms included active AcrA/B and OqxAB efflux pumps respectively. The result showed the Carba NP test was more specific than MHT. Data confirmed the involvement of AcrA/B and OqxAB efflux pump as a carbapenem resistance mechanism in selected bacteria. Similar to other reports from the Middle East, we found OXA-48 and NDM-1 to be the most frequent carbapenemase.

Occurrence and Phenotypic Characterization of Multidrug-Resistant Bacterial Pathogens Isolated from Patients in a Public Hospital in Mogadishu, Somalia

Purpose

This study reports a cross-sectional investigation to determine the antimicrobial resistance pattern of the common bacterial contaminants isolated from hospitalized patients in Mogadishu, Somalia.

Materials and Methods

A total of 328 clinical samples comprising urine, blood, vaginal swab, pus aspirates, and stool were collected from a public hospital located in Mogadishu the capital city of Somalia between October 2019 to March 2020. The isolation and biochemical characterization of the bacterial isolates were performed using the conventional culture and biochemical assay tests. Similarly, antimicrobial susceptibility was determined using the Kirby–Bauer disk diffusion.

Results

A total of 275 pathogenic bacteria that include Staphylococcus aureus, Escherichia coli, Pseudomonas aeroginosa, Proteus vulgare, Klebsiella pneumonia, and Salmonella spp. were detected with an overall detection rate of 78.4% (257/328). Among the bacterial pathogens isolated from clinical specimens, 152 (46.3%) were Staphylococcus aureus, 60 (18.3%) were E. coli, 10 (3.1%) Proteus vulgaris, 6 (1.8%) Klebsiella pneumonia, and 1 (0.3%) isolate was found to be Salmonella sp. The antimicrobial susceptibility assay revealed variable resistance pattern with clindamycin (40%), ampicillin (27%), vancomycin (26%), levofloxacin (23%), amoxicillin (20%), ciprofloxacin (18%) and nitrofurantoin (12%) showing the highest rate of resistance. Moreover, evaluation of multidrug resistance showed that Staphylococcus aureus had the highest multidrug resistance rate, with 19 isolates showing resistance to more than two drugs, followed by E. coli with three isolates. In contrast, each of Proteus vulgare, Salmonella sp. and Klebsiella pneumonia had one isolate each that exhibited multidrug resistance characteristics.

Conclusion

The findings of this study showed the occurrence of a number antimicrobial-resistant bacterial pathogens whose prevalence varies with age and sex. Therefore, there is a need for comprehensive antimicrobial profiling of bacterial isolates during the management of patients in the hospital.

Detection and characterization of Enterobacteriaceae family members carried by commensal Rattus norvegicus from Tehran, Iran

Wild rats are known to carry different microorganisms and are considered a reservoir of zoonotic pathogens worldwide. The urban rats were collected from five districts of Tehran and Gram-negative bacteria (GNB) were isolated from fecal samples and were identified using classical biochemical tests. The antibiotic susceptibility patterns of isolated bacteria were determined by Kirby-Bauer disk diffusion method, the results of which were interpreted in line with CLSI guideline. The frequency of antibiotic-resistant genes was identified using multiplex-PCR. Moreover, PCR method was used to identify the frequency of Escherichia coli O157:H7 and main categories of diarrheagenic E. coli including EPEC, ETEC, EIEC, EAEC, and STEC pathotypes. A total of 100 Rattus norvegicus were trapped and fecal samples were collected. Overall, 72 fecal samples were positive for GNB. E. coli (n = 46/72) had the highest frequency among the isolated GNB. Among E. coli isolates, the highest and lowest resistance rates belonged to ampicillin (56.5%) and ceftriaxone (0%), respectively. Klebsiella spp. was 100% resistant to imipenem, and streptomycin (0%) was the most effective antimicrobial agent on Klebsiella spp. Among surveyed genes, bla_TEM (95.8%) and bla_aadA-1 (58.3%) had the highest frequency, while bla_KPC, and bla_CMY-2 were not detected among Enterobacteriaceae. Herein, O157: H7 serotype was not detected and aEPEC (87%) was the most common pathotype detected. Results suggested that rodents might be a reservoir of antimicrobial-resistant pathogens and rodent control along with implementation of surveillance programs should be considered as a critical priority for urban health.

Extracellular products-mediated interspecific interaction between Pseudomonas aeruginosa and Escherichia coli

The Gram-negative pathogen Pseudomonas aeruginosa adopts several elaborate strategies to colonize a wide range of natural or clinical niches and to overcome the neighboring bacterial competitors in polymicrobial communities. However, the relationship and interaction mechanism of P. aeruginosa with other bacterial pathogens remains largely unexplored. Here we explore the interaction dynamics of P. aeruginosa and Escherichia coli, which frequently coinfect the lungs of immunocompromised hosts, by using a series of on-plate proximity assays and RNA-sequencing. We show that the extracellular products of P. aeruginosa can inhibit the growth of neighboring E. coli and induce a large-scale of transcriptional reprogramming of E. coli, especially in terms of cellular respiration-related primary metabolisms and membrane components. In contrast, the presence of E. coli has no significant effect on the growth of P. aeruginosa in short-term culture, but causes a dysregulated expression of genes positively controlled by the quorum-sensing (QS) system of P. aeruginosa during subsequent pairwise culture. We further demonstrate that the divergent QS-regulation of P. aeruginosa may be related to the function of the transcriptional regulator PqsR, which can be enhanced by E. coli culture supernatant to increase the pyocyanin production by P. aeruginosa in the absence of the central las-QS system. Moreover, the extracellular products of E. coli promote the proliferation and lethality of P. aeruginosa in infecting the Caenorhabditis elegans model. The current study provides a general characterization of the extracellular products-mediated interactions between P. aeruginosa and E. coli, and may facilitate the understanding of polymicrobial infections.

The Role of the Coagulase-negative Staphylococci (CoNS) in Infective Endocarditis; A Narrative Review from 2000 to 2020

Coagulase-negative staphylococci (CoNS) are part of the microbiota of human skin and rarely linked with soft tissue infections. In recent years, CoNS species considered as one of the major nosocomial pathogens and can cause several infections such as catheter-acquired sepsis, skin infection, urinary tract infection, endophthalmitis, central nervous system shunt infection, surgical site infections, and foreign body infection. These microorganisms have a significant impact on human life and health and, as typical opportunists, cause peritonitis in individuals undergoing peritoneal dialysis. Moreover, it is revealed that these potential pathogens are mainly related to the use of indwelling or implanted in a foreign body and cause infective endocarditis (both native valve endocarditis and prosthetic valve endocarditis) in patients. In general, approximately eight percent of all cases of native valve endocarditis is associated with CoNS species, and these organisms cause death in 25% of all native valve endocarditis cases. Moreover, it is revealed that methicillin-resistant CoNS species cause 60 % of all prosthetic valve endocarditis cases. In this review, we describe the role of the CoNS species in infective endocarditis, and we explicated the reported cases of CoNS infective endocarditis in the literature from 2000 to 2020 to determine the role of CoNS in the process of infective endocarditis.

Evaluating the antibiotic resistance and frequency of adhesion markers among Escherichia coli isolated from type 2 diabetes patients with urinary tract infection and its association with common polymorphism of mannose-binding lectin gene

The present paper aims to determine the frequency and antibiotic resistance patterns of pathogenic bacteria, the virulence factor profile of Escherichia coli and mannose-binding lectin (MBL) gene polymorphism in individuals with diabetes mellitus (DM) and urinary tract infection (UTI). The population under study was 130 individuals with type 2 diabetes mellitus (T2DM) and UTI. The patients' clinical characteristics and urine and blood samples (5 mL) were collected. Antibiotic resistance was determined using a disc diffusion method, and the results were interpreted according to CLSI. The presence of virulence genes was detected by multiplex PCR. To detect the MBL gene polymorphism, PCR and restriction fragment length polymorphism methods were applied. The predominant Gram-negative and Gram-positive bacteria included E. coli and Streptococcus spp.viridans group, respectively. Women were more susceptible to the incidence of UTI than men. The E. coli isolates showed a high level of resistance to amoxicillin-clavulanic acid (87.35%), and nitrofurantoin and ceftizoxime were the most effective antimicrobial agents for E. coli. Cefotaxime and ceftizoxime were the most effective antimicrobial agents for Enterobacter spp., norfloxacin and ciprofloxacin were the most effective antimicrobial agents for Staphylococcus epidermidis and Staphylococcus saprophyticus. papGII (52.87%) and papEF (1.14%) had the highest and lowest frequency among examined genes in E. coli isolates, respectively. The GG genotype had the highest frequency among patients with T2DM and UTI. Results showed that the detection of E. coli in individuals with an AA genotype, codon 54 of the MBL gene, can play an important role in the molecular diagnosis and timely treatment of bacterial infections in individuals with diabetes.

Three Years of Evaluation to Determine Reduction of Antibiotic Resistance in Gram-Negative Bacteria by the Saudi National Action Plan

Background

Bacterial antibiotic resistance (AR) is a primary public health concern. In 2017, the Saudi National Action Plan (SNAP) implemented several strategies to overcome AR. Here, to better understand the effectiveness of that plan, we evaluated the rates of AR, extended-spectrum beta-lactamase (ESBL) positivity, and multi-drug resistance (MDR) among gram-negative bacteria in a private Saudi hospital.

Methods

This retrospective study included all patients with a confirmed diagnosis of gram-negative bacterial infection from January 2017 to December 2019. Identification of bacterial strains was performed using VITEK 2 ID-GNB cards, while AR, ESBL, and MDR were determined using AST-No. 12 cards, both used as recommended by the manufacturer. Cards were loaded into a VITEK 2 system for examination.

Results

A total of 4760 isolated gram-negative bacteria were collected. The most isolated organism was Escherichia coli, with 2585/4760 (54.30%) strains, and the least was Providencia stuartii, with 55/4760 (1.16%) strains. A total of 1328/4760 (27.90%) clinical isolates were ESBL-positive, and 851/4760 (17.88%) possessed MDR. Escherichia coli was also the most frequently isolated as having ESBL activity and MDR, with 772/1328 (58.13%) and 292/851 (34.31%) isolates, respectively. Between 2017 and 2019, the rates of ESBL and MDR were significantly reduced (p < 0.05) for most bacteria, except for Salmonella species, which showed increased resistance to antibiotics.

Conclusion

Our findings revealed that the rates of AR, ESBL, and MDR reduced over time, which suggests the SNAP is effective at overcoming AR risk.

Synergistic Effect of Tazobactam on Amikacin MIC in Acinetobacter baumannii Isolated from Burn Patients in Tehran, Iran

BACKGROUND

Burn is still an important global public health challenge. Wound colonization of antibiotic resistant bacteria such as Acinetobacter baumannii can lead to high morbidity and mortality in burn patients. The aim of this study was to evaluate the inhibitory effect of tazobactam on efflux pump, which can cause aminoglycoside resistant in A. baumannii isolated from burn patients.

METHODS

In this study, 47 aminoglycoside resistant A. baumannii spp. were obtained from burn patients, admitted to the Shahid Motahari Burns Hospital in Tehran, Iran, during June-August 2018. The inhibitory effect of tazobactam against adeB such as efflux pump was evaluated by Minimum Inhibitory Concentration (MIC) determination of amikacin alone and in combination with tazobactam. Fractional Inhibitory Concentration index (FIC) was used to determine the efficacy of tazobactam/ amikacin combination. Further, semi-quantitative Real- Time PCR was performed to quantify the expression rates of the adeB gene before and after addition of tazobactam/amikacin.

RESULTS

The MIC values were significantly reduced when a combined amikacin and tazobactam was utilized. The most common interaction observed was synergistic (78.2%), followed by.additive effects (21.8%), as per FIC results. The adeB mRNA expression levels were found to be downregulated in 60.7% of isolates treated with tazobactam.

CONCLUSION

Tazobactam can have impact on resistance to aminoglycoside by inhibiting efflux pump. Thus, the combination of tazobactam with amikacin can be used as an alternative treatment approach in multidrug resistant A. baumannii infections.

Resistance pattern of Escherichia coli to levofloxacin in Iran: a narrative review

Fluoroquinolones (FQs) are widely used in the treatment of infections caused by Escherichia coli. FQs are broad spectrum antibiotics with high tissue penetration, and ease of use. Therefore, given the concerns existing about drug resistance, we aim to review the latest findings about resistance patterns to levofloxacin (LVX) along with other FQs in E. coli infections in different parts of Iran. Evidence shows that quinolones have been used in Iran for nearly 50 years, and that 0-65% of E. coli isolates show resistance to FQs. In the western parts of Iran, the highest rate of resistance to LVX (66.7%) has been reported among patients having urinary tract infections with E. coli isolates. Few studies and information exist on the antimicrobial resistance of E. coli to LVX in different geographical locations of Iran. However, the findings of various studies on this subject show that E. coli resistance to LVX is more in the western part of Iran than in central and southern regions, but it is similar among inpatients and outpatients. Therefore, it is reasonable advisable to limit the overuse, inappropriate prescription, and self-medication of LVX to prevent the induction of FQ-resistant strains. Accordingly, in order to obtain a clearer image of resistance to FQs, especially LVX in E. coli in Iran, more extensive investigations in different geographical locations and periods of time are required. In addition, antimicrobial stewardship would be helpful in this regard.

Combination of Silver Nanoparticles and Vancomycin to Overcome Antibiotic Resistance in Planktonic/Biofilm Cell from Clinical and Animal Source

This study aims to evaluate the prevalence of multidrug-resistant (MDR) and biofilm-forming pathogens from animal source compared to clinical ones. In addition, to assess the antibacterial and antibiofilm activity of silver nanoparticles (AgNPs) alone and/or mixed with vancomycin. Out of 62 bacterial isolates from animal respiratory tract infection (RTI), 50.00% were defined as MDR, while among human ones, 44.00% were MDR. The bacteria Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae were the predominant isolated bacteria from both animal and human origin with frequency percentage of 50.00, 22.32, and 18.75, respectively. Among Staph. aureus strains, mecA gene was detected in 60.00% and 61.54% of animal and human isolates, respectively, while mec_ALGA251 (mecC) gene was detected in 13.33% and 15.38% of animal and human isolates, respectively. Biofilm formation ability among animal isolates was 83.87%, while among human ones was 86.00%. AgNPs were effective in inhibiting planktonic cells with minimal inhibitory concentration (MIC) values (0.625-10 μg/mL), as well as eradicating biofilm with minimal biofilm eradication concentration values (1.25-10 μg/mL). Noticeable low MIC of AgNPs was required for the isolates from animal source (0.625-5 μg/mL) compared to clinical ones (0.625-10 μg/mL). Remarkable reduction in AgNP effective concentration was observed after combination with 1/4 MIC of vancomycin with minimum recorded concentration of 0.08 μg/mL. In conclusion, the prevalence of MDR among RT pathogens was recorded with high ability to produce biofilm and virulence factors from both animal and human pathogens. AgNPs showed strong antibacterial and antibiofilm activity alone and mixed with vancomycin, with up to fourfold reduction of AgNP inhibitory dose.

Evaluating the antimicrobial resistance patterns and molecular frequency of bla oxa-48 and bla GES-2 genes in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from burn wound infection in Tehran, Iran

The aim of this study is to evaluate the antimicrobial resistance patterns and molecular frequency of bla_GES-2 and bla_oxa-48 genes in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from burn wound infection in Tehran, Iran. In this study, 50 isolates of A. baumannii and 48 isolates of P. aeruginosa were collected from the Burn Unit of Shahid Motahari Hospital at Tehran, Iran. Antibiotic susceptibility tests of all isolates were carried out using the disc diffusion method, and the production of extended-spectrum β-lactamases (ESBLs) in isolates was surveyed by the double disc synergy method and based on CLSI (2019 AST M100) criteria. Finally, the frequency of bla_GES-2 and bla_oxa-48 genes was surveyed by PCR. Antibiotic susceptibility tests showed that 48/48 (100%) of P. aeruginosa isolates and 49/50 (98%) of A. baumannii isolates were resistant to ceftriaxone and cefotaxime, respectively. Ceftazidime exhibited the lowest (26/48; 54.1%) resistance rates against P. aeruginosa isolates. The production of ESBLs was seen in 8/48 (16.6%) and 3/50 (6%) of P. aeruginosa and A. baumannii isolates, respectively. On the basis of conventional PCR and sequencing, the frequencies of the bla_GES-2 gene among P. aeruginosa and A. baumannii was 87.5% and 58%, respectively. Moreover, bla_oxa-48 gene was detected in 70.83% and 92% of P. aeruginosa and A. baumannii isolates, respectively. Results suggest that antibiotic-resistant A. baumannii and P. aeruginosa strains isolated from burn patients are frequently found; therefore, it is absolutely necessary to implement continuous screening and follow-up programmes for detecting antimicrobial resistance.

Seroprevalence of Epstein-Barr virus among children and adults in Tehran, Iran

Epstein–Barr virus (EBV) as a herpes virus can be associated with numerous infections and cancers. The virus is known to cause infectious mononucleosis. There is no accurate estimation of the seroprevalence of EBV in Tehran, so this study aimed to estimate the seroprevalence of EBV among children and adults in Tehran, Iran. This descriptive–analytical study was conducted from 2015 to 2019 in Tehran province. In this study, 1220 people were selected by cross-sectional sampling, and blood samples and demographic data were collected by questionnaire. An anti-EBV-VCA ELISA kit was used to determine the seroprevalence of IgG against viral capsid antigen (VCA) among children and adults. In this study, most of the participants were in the age range of 20–29 years (349 individuals). The results of the ELISA test showed that the highest number of positive cases were in people over 40 years (94.8%), 30–39 years (92.5%) and 20–29 years were (92.1%), respectively. On the other hand, the seroprevalence of EBV infection in boys and girls up to 3 years was about 50%, and in adults, up to 40 years, it was about 95% (p < 0.001). The results of this study showed that in Tehran, the seroprevalence of VCA-IgG varied from 70% in primary school children to more than 90% in adults up to 40 years, indicating a broad spread of the virus. The results also indicate that the seroprevalence of EBV is high among men and women in Tehran.