Antimicrobial resistance pattern, virulence determinants and molecular analysis of Enterococcus faecium isolated from children infections in Iran

Molecular Analysis of Enterococcus Faecalis Isolates in a 4-year Period

In the present research, we aimed to determine the characteristics of E. faecalis strains collected from an Iranian Children's Hospital for four years. Sixty-seven E. faecalis isolates with virulence genes detection, variable-number tandem repeat (VNTR), and multiple-locus variable-number tandem repeat analysis (MLVA) typing were investigated. A high frequency of virulence genes belonged to gelatinase (73%) and Enterococcus faecalis (62%). The MLVA of 67 E. faecalis isolates revealed 52 VNTR patterns and 38 MLVA types (MTs). Furthermore, genetic diversities with the majority of the MT1 as a major MT in different Wards of the Children's Hospital were found.

Human enterococcal isolates as reservoirs for macrolide-lincosamide-streptogramin and other resistance genes

According to recent studies, the importance of MLS (macrolide-lincosamide-streptogramin) resistance phenotypes and genes in enterococci are reflected in the fact that they represent reservoirs of MLS resistance genes. The aim of this study was to investigate distribution of MLS resistance genes and phenotypes in community- and hospital-acquired enterococcal isolates and to determine their prevalence. The MLS resistance phenotypes (cMLSb, iMLSb, M/MSb, and L/LSa) were determined in 245 enterococcal isolates were characterized using the double-disc diffusion method. Specific primers were chosen from database sequences for detection of the MLS resistance genes (ermA, ermB, ermC, msrA/B, lnuA, lnuB, and lsaA) in 60 isolates of enterococci by end-point PCR. There was no linezolid-resistant enterococcal isolate. Only one vancomycin-resistant (0.6%) isolate was found and it occurred in a community-acquired enterococcal isolate. The most frequent MLS resistance phenotype among enterococcal isolates was cMLSb (79.7% community- and 67.9% hospital-acquired). The most common identified MLS resistance genes among enterococcal isolates were lsaA (52.9% community- and 33.3% hospital-acquired) and ermB (17.6% community- and 33.3% hospital-acquired). The most prevalent MLS gene combination was lnuA + lsaA (five enterococcal isolates). The ermB gene encoded cMLSb phenotype, and it was identified in only one isolate that displayed iMLSb resistance phenotype. Based on the results obtained, we can conclude that the most frequent MLS resistance phenotype among enterococcal isolates was cMLSb. Surprisingly, a vancomycin-resistant enterococcal isolate was identified in a community-acquired enterococcal isolate. This study shows that enterococci may represent a major reservoir of ermB, lsaA, and lnuA genes.

Retrospective Analysis of Antimicrobial Susceptibility of Uropathogens Isolated from Pediatric Patients in Tertiary Hospital at Al-Baha Region, Saudi Arabia

Introduction: Prompt diagnosis and initiation of treatment are essential in preventing long-term renal scarring. However, increasing antibiotic resistance may delay the initiation of appropriate therapy. Methodology: A retrospective chart review was performed for patients admitted to the pediatric department with urinary tract infection (UTI) diagnosis in a large tertiary care hospital in Al Baha, Saudi Arabia, from May 2017 to April 2018. The study included children of both sexes under the age of 14 years. Results: Out of 118 urinary bacterial samples, Escherichia coli was the main etiologic agent in the community- and hospital-acquired infections. The infection rate was higher in girls (68.64%) than in boys (31.36%). The commonest isolates were Escherichia coli (44.07%), extended-spectrum beta-lactamase-producing Escherichia coli (11.86%), Klebsiella pneumoniae (9.32%), Enterococcus faecalis (7.63%), methicillin-resistant Staphylococcus epidermidis (4.24%), and coagulase-negative Staphylococci (3.39%). The current study demonstrates that nitrofurantoin (19%) was the most commonly prescribed medication in the inpatient and outpatient departments, followed by trimethoprim/sulfamethoxazole (16%), amoxicillin/clavulanic acid (15%), cefuroxime (10%), azithromycin (8%), ceftriaxone (7%), and ciprofloxacin (4%), while amikacin, amoxicillin, ampicillin, cefepime, imipenem, phenoxymethylpenicillin were prescribed less commonly due to the high resistance rate. Conclusion: The microbial culture and sensitivity of the isolates from urine samples should be routine before starting antimicrobial therapy. Current knowledge of the antibiotic susceptibility patterns of uropathogens in specific geographical locations is essential for choosing an appropriate empirical antimicrobial treatment rather than reliance on recommended guidelines.

Biological characteristics and anti-biofilm activity of a lytic phage against vancomycin-resistant Enterococcus faecium

BACKGROUND AND OBJECTIVES

An important leading cause of the emergence of vancomycin-resistant enterococci, especially Enterococcus faecium, is the inefficiency of antibiotics in the elimination of drug-resistant pathogens. Consequently, the need for alternative treatments is more necessary than ever.

MATERIALS AND METHODS

A highly effective bacteriophage against vancomycin-resistant E. faecium called vB-EfmS-S2 was isolated from hospital sewage. The biological properties of phage S2 and its effect on biofilm structures were determined.

RESULTS

Phage S2 was specifically capable of lysing a wide range of clinical E. faecium isolates. According to Electron microscopy observations, the phage S2 belonged to the Siphoviridea family. Suitable pH spectra for phage survival was 5-11, at which the phage showed 100% activity. The optimal temperature for phage growth was 30-45°C, with the highest growth at 37°C. Based on one-step growth curve results, the latent period of phage S2 was 14 min with a burst size of 200 PFU/ml. The phage S2 was also able to tolerate bile at concentrations of 1 and 2% and required Mg2+ for an effective infection cycle. Biofilms were significantly inhibited and disrupted in the presence of the phage.

CONCLUSION

According to the results, phage S2 could potentially be an alternative for the elimination and control of vancomycin-resistant E. faecium biofilm.

Foodborne ESKAPE Biofilms and Antimicrobial Resistance: lessons Learned from Clinical Isolates

The ESKAPE pathogens (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) are identified to be multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan drug-resistant (PDR); thereby, imposing severe challenges in the treatment of associated infections. ESKAPE pathogens colonize on various biotic and abiotic surfaces; biofilms formed by these pathogens are a potential source for food contamination. Moreover, biofilms play a pivotal role in the development of antimicrobial-resistant (AMR) strains. Hence, the frequent isolation of antimicrobial-resistant ESKAPE pathogens from food products across the globe imposes a threat to public health. A comprehensive understanding of the adhesion signaling involved in the polymicrobial and single-species biofilm will assist in developing alternative preservation techniques and novel therapeutic strategies to combat ESKAPE pathogens. The review provides a comprehensive overview of the signaling mechanisms that prevail in the ESKAPE pathogens for adhesion to abiotic and biotic surfaces and molecular mechanisms associated with poly-microbial biofilm-assisted AMR in ESKAPE.

Antimicrobial Resistance and Virulence Factor Gene Profiles of Enterococcus spp. Isolated from Giant Panda Oral Cavities

Introduction

The objective of this study was to determine the prevalence and characteristics of antimicrobial-resistant Enterococcus faecalis and E. faecium isolated from the oral cavities of captive giant pandas in China.

Material and Methods

The virulence-associated determinant and antimicrobial resistance genes were detected and antimicrobial susceptibility tests were performed on 54 strains of each bacterium.

Results

All isolates showed 100% multidrug resistance. E. faecalis isolates showed a higher percentage of strains resistant to gentamicin (48.1%), vancomycin (55.6%), linezolid (100%), and streptomycin (33.3%) than E. faecium isolates. The resistance genes of Enterococcus spp. were present to highly varying extents according to antibiotic type, their presence breaking down for E. faecalis and E. faecium respectively as aac(6')/aph(2″) 5.56% and 5.56%; aph(3')-Ⅲ 0% and 14.81%; ant(6)-I 0% and 3.7%; ant(4')-Ia 0% and 64.81%; tetL 20.37% and 100%; vanA 92.59% and 46.3%; vanB 0% and 0%; cfr 0% and 90.74%; optrA 96.3% and 3.7%; blaZ 0% and 1.85%; blaTEM 0% and 0%; tetA 20.37% and 0%; tetC 24.07% and 100%; tetM 0% and 0%; ermA 12.96% and 100%; ermB 5.56% and 3.7%; and ermC 0% and 1.85%.Virulence-associated determinants were detected in this research, which typically include efaA, gelE, asa1, ace, cylA, esp and hyl; however, the latter three were not detected. High proportions of the isolates carried the efaA, gelE, asa1, and ace genes. Respectively for E. faecalis and E. faecium their detection was efaA 98.1% and 85.2%; gelE 98.1% and 87%; asa1 92.6% and 87%; and ace 87% and 85.2%.

Conclusion

This is the first study on the potential disease risk and antimicrobial-resistant characteristics of E. faecalis and E. faecium isolates in giant panda oral cavities. The results of this study show that the antimicrobial resistance rate of Enterococcus spp. isolated from the oral cavity of captive pandas is very high, and thus needs to be monitored.

Inhibition of the Classical Pathway of Complement Activation Impairs Bacterial Clearance during Enterococcus faecalis Infection

Enterococcus faecalis infections are considered a major public health concern worldwide. The complement system has a crucial role in the protection against different microbial pathogens, including E. faecalis Complement can be activated through three different pathways, including the classical, lectin, and alternative pathways. There is limited information on the role of the classical pathway (CP) in protection against infections caused by E. faecalis In the present study, we generated Fab fragments that successfully block the CP in mouse via inhibition of a key enzyme, C1s-A. Our results showed that anti-C1s-A Fab fragments block CP-mediated C3b and C4b deposition in vitro We further showed that administration of anti-C1s-A Fab fragments significantly impairs the CP functional activity in vivo Moreover, treatment of mice infected with E. faecalis using anti-C1s-A Fab fragments significantly impairs bacterial clearance as determined from the viable bacterial counts recovered from blood, kidneys, spleens, livers, and lungs of infected mice. Overall, this study highlights the essential role of the CP in host defense against E. faecalis.

The Existence of High Bacterial Resistance to Some Reserved Antibiotics in Tertiary Hospitals in Tanzania: A Call to Revisit Their Use

Background

Antibiotic resistance poses burden to the community and health-care services. Efforts are being made at local, national and global level to combat the rise of antibiotic resistance including antibiotic stewardship. Surveillance to antibiotic resistance is of importance to aid in planning and implementing infection prevention and control measures. The study was conducted to assess the resistance pattern to cefepime, clindamycin and meropenem, which are reserved antibiotics for use at tertiary hospitals in Tanzania.

Methods

A hospital-based antibiotic resistance surveillance was conducted between July and November 2019 at Muhimbili National Hospital and Bugando Medical Center, Tanzania. All organisms isolated were identified based on colony morphology, Gram staining and relevant biochemical tests. Antibiotic susceptibility testing was performed on Muller-Hinton agar using Kirby-Bauer disc diffusion method. Antibiotic susceptibility was performed according to the protocol by National Committee for Clinical Laboratory Standards.

Results

A total of 201 clinical samples were tested in this study. Urine (39.8%, n=80) and blood (35.3%, n=71) accounted for most of the collected samples followed by pus (16.9%, n=34). The bacterial resistance to clindamycin, cefepime and meropenem was 68.9%, 73.2% and 8.5%, respectively. About 68.4% Staphylococcus aureus isolates were resistant to clindamycin whereby 56.3%, 75.6%, 93.8% and 100% of the tested Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa and Enterobacter cloacae, respectively, were cefepime resistant. About 8.5% of isolated Klebsiella spp were resistant and 6.4% had intermediate susceptibility to meropenem. Also, Pseudomonas aeruginosa was resistant by 31.2% and 25% had intermediate susceptibility to meropenem.

Conclusion

The bacterial resistance to clindamycin and cefepime is high and low in meropenem. Henceforth, culture and susceptibility results should be used to guide the use of these antibiotics. Antibiotics with low resistance rate should be introduced to the reserve category and continuous antibiotic surveillance is warranted.

Antibiotic Resistance And Genotyping Of Gram-Positive Bacteria Causing Hospital-Acquired Infection In Patients Referring To Children's Medical Center

Introduction

A serious problem affecting human society is the development of bacterial resistance. The purpose of the current study was to evaluate the antibiotic resistance of Gram-positive bacteria (GPB) and genotyping of common GPB causing hospital-acquired infections (HAIs) in patients who were referred to Children’s Medical Center during a 6-month period by random amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus sequence polymerase chain reaction (ERIC-PCR).

Methods

During the 6-month period, antimicrobial resistance profiles of GPB isolates recovered from patients in Children’s Medical Center were determined using the Kirby–Bauer disk diffusion and MIC. Typing of common GPB was performed and the results were analyzed by gel compare software.

Results

In this cross-sectional study, 6524 cultures were performed and 138 Ggram-positive bacteria were isolated (2%). Staphylococcus aureus strains showed the highest antibiotic penicillin resistance (96.3%). Twenty-six per cent of the strains were methicillin-resistant S. aureus (MRSA) and no resistance was found against vancomycin. All isolates of Enterococcus faecium were resistant to ciprofloxacin (100%). The resistance to vancomycin was very high (67%) and no resistance was observed to linezolid. The results of genotyping analysis of S. epidermidis strains showed the presence of two clones with a genetic relationship of over 80%. All of the S. aureus strains were in one cluster and half of the E. faecium strains were in a cluster with a genetic predilection of over 80%.

Conclusion

This study indicated frequent occurrence of antimicrobial resistance, especially in Enterococcus spp. isolates. Rapid spreads of MRSA and VREF from a clonal origin require implementing careful isolation and infection control measures.