Antibiotic Resistance and Molecular Epidemiology of Vancomycin-Resistant Enterococci in a Tertiary Care Hospital in Turkey

High Gastrointestinal Colonization Rate of Vancomycin-Resistant Enterococci among Hospitalized Patients: Potential Source for Resistant Gene

Background

Vancomycin-resistant Enterococci (VRE) is a global health problem and responsible for healthcare-associated infections (HAIs) in patients with prolonged hospital stay, severe underlying disease, and previous broad-spectrum antibiotic therapy. These bacteria can cross-resist and transfer drug-resistant genes to other potentially pathogenic bacteria. Therefore; this study was aimed to determine the gastrointestinal colonization rate of VRE, its antimicrobial susceptibility profile, and associated factors among hospitalized patients.

Methods

Prospective cross-sectional study was conducted using stool samples from 223 patients admitted to different wards at Hawassa University Comprehensive Specialized Hospital, from April 1 to June 30, 2021. Patients admitted to the hospital for more than 48 hours for various medical conditions were included. Sociodemographic and clinical characteristics were collected using a structured questionnaire. Fecal specimens were cultured on Enterococci selective media. Enterococcus species were identified using their growth and mannitol fermentation properties. Vancomycin resistance was screened using both the Kirby-Bauer disk diffusion method and a vancomycin E-test strip. Data were entered and analyzed using SPSS version 25. Descriptive and logistic regressions were used to determine the frequency and association of factors with the VRE colonization rate. A p value of <0.05 was considered statistically significant.

Results

A total of 223 fecal specimens were collected and processed, and 141 (63.2%) them were positive for Enterococci. The predominant species was E. faecalis 65 (46.1%) followed by E. faecium 76 (53.9%). In this study, the gastrointestinal colonization rate of VRE was 15 (6.7%) and all the species belong to E. faecium. Study participants who had no formal education (AOR = 4.26, 95% CI: 1.01, 18.06), hospitalized patients for >2 weeks (AOR = 4.10, 95% CI: 1.08, 15.57), and those who had a history of treatment with vancomycin (AOR = 4.77, 95% CI: 1.26, 18.09) were more likely to be colonized with vancomycin-resistant Enterococci. More than 95% of Enterococci isolates were susceptible to linezolid, whereas 70.2%, 63.1%, 56.7%, and 53.9% were resistant to tetracycline, erythromycin, penicillin, and ampicillin, respectively. Among the total Enterococci isolated, 141 (54.6%) were multidrug resistant.

Conclusions

In our study, high proportion of vancomycin-resistant Enterococci was found. Previous exposure to antibiotics and hospital stay were significant factors for VRE gut colonization. The isolated Enterococci showed variable degrees of resistance to commonly prescribed antibiotics which leads to a worldwide problem multidrug resistance. Therefore, periodic surveillance on antimicrobial resistance pattern, adhering to rational use of antibiotics, and implementing infection prevention protocols may reduce colonization by VRE.

An Outbreak of Vancomycin-Resistant Enterococci in a City Hospital Intensive Care Unit: Molecular Characterization of Resistance

Background and Objectives: Vancomisin-resistant Enterococci (VRE), is a resistant microorganism that colonizes and causes infections in hospitalized patients. The aim of this study was to show the spread of vancomycin-resistant Enterococcus faecium (VREfm) step-by-step in all intensive care units, which started with the growth of VREfm on 2 December 2021 in the blood culture of a patient hospitalized in the anesthesia intensive care unit of our hospital and was found to have reached epidemic size in the surveys. Materials and Methods: Rectal swab samples were taken from all patients hospitalized in intensive care units, VRE colonization was determined, the VanA and VanB resistance genes associated with the vancomycin resistance of VREfm isolates were determined by PCR method, and clonal association analysis was performed by Arbitrarily Primed-PCR (AP-PCR) and PFGE (pulsed-field gel electrophoresis). Results: In our study, VRE were detected in 61 of 2601 rectal swab samples. In total, fifty-four (85.52%) of the VRE isolates were Enterococcus faecium, three (4.91%) was Enterococcus faecalis, three (4.91%) was Enterococcus gallinorum, and one (1.63%) was Enterococcus casseliflavus. It was determined that all of the 54 VREfm isolates, which were the most detected among all VRE isolates, carried the vanA gene. In the clonal association analysis of the isolates by AP-PCR and PFGE methods, it was found that they had 12 different genotypes, 48 of them were included in any cluster, the clustering rate was 88.8%, and the largest cluster was the genotype 1 cluster, with 36 isolates. Of the 54 patients with VREfm isolated recently, 18.51 percent of the clinical samples were isolated before the survey, and 9.25% were isolated after the survey. It was determined that 100% of VREfm isolates were resistant to ampicillin, levofloxacin, ciprofloxacin, high-level gentamicin, trimethoprimsulfamethoxazole, and teicoplanin, 7.4% to tigecycline, and 1.85% to linezolid. Conclusions: In our study, in the clonal association analysis performed by isolating VREfm in rectal swab samples, it was found that 88.8% of the samples were indistinguishably similar, and that the increase in the number of VREfm infections after the index case in our hospital was associated with the epidemic. VREfm infections cause long-term hospitalization, costs and also deaths, which shows the seriousness of the event, and the importance of the combination of epidemiological and molecular analysis in epidemic research.

The prevalence and molecular epidemiology of vancomycin-resistant Enterococcus (VRE) carriage in patients admitted to intensive care units in Beijing, China

BACKGROUND

Vancomycin-resistant Enterococcus (VRE) can be carried in the gut for a long period and its carriage status is associated with subsequent infections. This study aimed to investigate the frequency of intestinal VRE carriage in intensive care patients in Beijing.

METHODS

A multicenter, retrospective cross-sectional study was conducted at six hospitals in Beijing, China. All patients admitted to intensive care units (ICUs) between April 2 and May 1, 2017, were enrolled, and their clinical data were gathered by reviewing electronic medical records. Rectal swabs collected from patients were stored at -80 °C in the Institute of Clinical Pharmacology, Peking University First Hospital, and they were selectively cultured for VRE, then the identified strains were analyzed by polymerase chain reaction (PCR) to detect the glycopeptide resistance gene and were characterized by multilocus sequence typing (MLST).

RESULTS

Of 148 patients recruited, 46 (31.1%) carried VRE, with the majority (n = 42) being Enterococcus faecium. In total, 78.3% of the VRE were vanA positive and 15.2% vanM positive, while 6.5% undetected glycopeptide resistance gene. The predominant ST was ST78 (47.6%) followed by ST192 (14.3%), ST555 (9.5%), and ST789 (9.5%). Multivariate analysis showed that factors associated VRE carriage were patients aged >65 years (odds ratio [OR], 3.786; 95% confidence interval [CI], 1.402-10.222) and recent third-generation cephalosporins use (OR, 6.360; 95% CI, 1.873-21.601).

CONCLUSIONS

The overall proportion of VRE carriage in patients admitted to ICUs was markedly high in Beijing, China. The vanM gene has been spread widely but vanA gene was the dominant resistance determinant in VRE in Beijing.

Vankomisine Dirençli Enterococcus faecium: Kısa Bir Derleme

Antimikrobiyal direnç (AMD) ile ilişkili morbidite ve mortalite küresel bir halk sağlığı sorunudur. Sağlık hizmeti ilişkili enfeksiyonlarda sık olarak görülen vankomisine dirençli Enterococcus faecium (VRE), Dünya Sağlık Örgütü’nün AMD’i olan öncelikli patojenler listesinde yüksek öncelik verdiği bir Gram pozitif koktur. Son zamanlarda Türkiye’de invaziv enfeksiyonlarda VRE izolasyon oranı %15.8 bildirilmiştir. Vankomisine direncin ana mekanizması, hedef bölgedeki D-Alanil-D-Alanin terminal molekülünün değişmesi ve ilacın affinitesinin azalmasıdır. Vankomisin direncinden sorumlu olan van geni kromozomal olarak kodlanmakta veya plazmid, transpozon gibi mobil genetik elemanlar ile kazanılmaktadır. Yayılımındaki ana mekanizma, mobil genetik elemanların Enterokoklar veya Staphylococcus aereus gibi farklı tür bakteriler arasında transfer edilebilmeleridir. Bu derlemede PubMed ve Web of Science veritabanlarında “Vankomisin-dirençli Enterococcus faecium”, “Vankomisin direnç mekanizmaları”, “Gram pozitif koklarda vankomisin direnci” terimleri ile arama yapılarak elde edilen literatür verileri özetlenmiş ve önerilerle birlikte kısaca tartışılmıştır.

The Analysis of Drug-Resistant Bacteria from Different Regions of Anhui in 2021

Purpose

To analyze the differences in clinical distribution and antimicrobial resistance of pathogens among northern Anhui, central Anhui, and southern Anhui in 2021, and to provide a basis for the rational use of drugs for clinicians in different regions.

Methods

Nonrepetitive pathogens isolated from clinical samples of inpatients and outpatients from 59 member units with qualified data in 2021 were obtained from the Anhui Province Antimicrobial Resistance Surveillance System, which was divided into northern Anhui, central Anhui, and southern Anhui by region. Identification and antimicrobial susceptibility analyses were carried out using the Vitek 2 Compact and standard disc diffusion method. The results were determined according to the American Clinical Laboratory Standards Institute in 2021 with data analyzed using WHONET 5.6 and SPSS 17.0.

Results

A total of 133,268 pathogenic bacteria were isolated from clinical samples. Staphylococcus aureus (S. aureus) was the most common gram-positive bacterium and Escherichia coli (E. coli) was the most common gram-negative bacterium. Sputum was the main source of clinical specimens. The detection rates of methicillin-resistant S.aureus, methicillin-resistant coagulase-negative Staphylococcus, carbapenem-resistant E. coli, carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae), carbapenem-resistant Acinetobacter baumannii, third-generation cephalosporin-resistant E. coli, and third-generation cephalosporin-resistant K. pneumoniae were higher in northern Anhui than in southern Anhui (P<0.0001). E. coli, K. pneumoniae, and Pseudomonas aeruginosa were sensitive to amikacin. Strains resistant to vancomycin, linezolid, and teicoplanin were not isolated until 2021.

Conclusion

There were significant differences in bacterial resistance in different regions of Anhui Province. Antibiotic resistance in northern Anhui was the most serious in 2021. Antimicrobial agents must be used according to the resistance of the bacteria in the local region.

Antibiogram Pattern and Virulence Trait Characterization of Enterococcus Species Clinical Isolates in Eastern India: A Recent Analysis

Objective We aimed to evaluate the current antimicrobial susceptibility pattern and characterize putative virulence traits among Enterococcus species isolates from various clinical specimens in view of their increased isolation rates in both community-related and serious nosocomial infections, as well as resistance to many antibiotics.

Methods Study (April 2017–March 2018) included consecutive, nonrepeated, discrete, and clinically significant isolates of enterococci. Susceptibility testing included detection of high-level aminoglycoside-resistant (HLAR) and glycopeptide-resistant enterococci (GRE). All screen-positive GRE isolates were investigated by polymerase chain reaction for species confirmation and presence of vanA/vanB genes. Virulence genes ace, asa1, cyt, efa, esp, gelE, and hyl were investigated by molecular methods. Hemolysin and biofilm production were studied using phenotypic methods.

Results Of 111 isolates, 89 (80.1%), 16 (14.4%), and 6 (5.4%) were from urine, pus, and blood, respectively, consisting predominantly of E. faecalis (67, 60.4%) and E. faecium (32, 28.8%). E. hirae (5, 4.5%) was the predominant non-E. faecalis non-E. faecium isolate. Other species were E. durans (4, 3.6%), E. avium (2, 1.8%), and E. mundtii (1, 0.9%). Seven (6.3%) out of the 111 isolates were GRE, all vanA genotype. HLAR was observed in 70 (63.1%) isolates, significantly higher in E. faecium than E. faecalis (81.2 vs. 58.2%; p < 0.05). All were susceptible to daptomycin. Hemolysin activity and biofilm production were observed in 38 (34.2%) and 36 (32.4%) isolates. Most frequent virulence genes were efa (77, 69.4%), ace (71, 63.9%), asa1 (67, 60.3%), and gelE (66, 59.4%). There was a predominant association of esp and hyl genes with E. faecium and that of the other genes with E. faecalis.

Conclusion The study will contribute to the existing limited data on virulence trait characterization of clinical E. spp. isolates in India. At the same time, it will help to serve as a guide in the choice of empirical therapy in enterococcal infections leading to favorable clinical outcomes by decreasing the clinical failure, microbiological persistence, and associated mortality, and will lead to future studies on controlling the spread of virulent and multiresistant isolates.

Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks

Backyard birds are small flocks that are more common in developing countries. They are used for poultry meat and egg production. However, they are also implicated in the maintenance and transmission of several zoonotic diseases, including multidrug-resistant bacteria. Enterococci are one of the most common zoonotic bacteria. They colonize numerous body sites and cause a wide range of serious nosocomial infections in humans. Therefore, the objective of the present study was to investigate the diversity in Enterococcus spp. in healthy birds and to determine the occurrence of multidrug resistance (MDR), multi-locus sequence types, and virulence genes and biofilm formation. From March 2019 to December 2020, cloacal swabs were collected from 15 healthy backyard broiler flocks. A total of 90 enterococci strains were recovered and classified according to the 16S rRNA sequence into Enterococcus faecalis (50%); Enterococcus faecium (33.33%), Enterococcus hirae (13.33%), and Enterococcus avium (3.33%). The isolates exhibited high resistance to tetracycline (55.6%), erythromycin (31.1%), and ampicillin (30%). However, all of the isolates were susceptible to linezolid. Multidrug resistance (MDR) was identified in 30 (33.3%) isolates. The enterococci AMR-associated genes ermB, ermA, tetM, tetL, vanA, cat, and pbp5 were identified in 24 (26.6%), 11 (12.2%), 39 (43.3%), 34 (37.7%), 1 (1.1%), 4 (4.4%), and 23 (25.5%) isolates, respectively. Of the 90 enterococci, 21 (23.3%), 27 (30%), and 36 (40%) isolates showed the presence of cylA, gelE, and agg virulence-associated genes, respectively. Seventy-three (81.1%) isolates exhibited biofilm formation. A statistically significant correlation was obtained for biofilm formation versus the MAR index and MDR. Multi-locus sequence typing (MLST) identified eleven and eight different STs for E. faecalis and E. faecium, respectively. Seven different rep-family plasmid genes (rep1–2, rep3, rep5–6, rep9, and rep11) were detected in the MDR enterococci. Two-thirds (20/30; 66.6%) of the enterococci were positive for one or two rep-families. In conclusion, the results show that healthy backyard chickens could act as a reservoir for MDR and virulent Enterococcus spp. Thus, an effective antimicrobial stewardship program and further studies using a One Health approach are required to investigate the role of backyard chickens as vectors for AMR transmission to humans.

Analysis of the phenotypic and genotypic antimicrobial resistance profiles of clinically significant enterococci isolated in the Provincial Specialist Hospital in Lublin, Poland

The increasing significance of enterococci as healthcare-associated pathogens can be linked to their limited susceptibility to antibiotics.

In this study, phenotypic and genotypic resistance profiles of 35 [n=18 E. faecium (Efm); n=17 E. faecalis (Efs)] invasive isolates cultured from hospitalized patients were analysed. Phenotypic identification was verified by the multiplex PCR targeting the 16S rDNA and the ddl genes encoding for the Efs and Efm – specific ligases. Antimicrobial susceptibility was determined using the disc diffusion method and E-tests. The high-level streptomycin resistance (HLSR), high-level gentamicin resistance (HLGR) and glycopeptide resistance was verified by amplification of the ant(6)-Ia, aac(6’)-Ie-aph(2’’)-Ia, as well as vanA and vanB genes, respectively.

More than 70% of all isolates were cultured from patients in the Intensive Care and Internal Medicine Units. Blood was the predominant (77%) site of isolation. All Efm isolates were resistant to ampicillin, imipenem, and norfloxacin; 17 isolates demonstrated high-level aminoglycoside resistance (HLAR), including 27.7% with HLSR, 38.8% with HLGR and 27.7% with both phenotypes. HLAR was also common in Efs (HLSR>70%, HLGR>50%), followed by norfloxacin (64.7%) and ampicillin (11.7%) resistance. The ant(6)-Ia and aac(6’)-Ie-aph(2’’)-Ia genes were detected in >90% of the HLSR and HLGR isolates, respectively. Glycopeptide resistance was detected in 4 (22.2%) Efm isolates and mediated by the vanA gene. 19 (54.3%) isolates were multidrug resistant, including 17 (89.5%) Efm. All isolates were susceptible to linezolid.

The study constitutes a contribution to the analysis of enterococcal antimicrobial resistance in Polish hospitals. The monitoring of enterococcal prevalence and antimicrobial resistance is crucial to control and prevent infections.

Prevalence of Vancomycin-Resistant Enterococci and Antimicrobial Residues in Wastewater and Surface Water

Due to the extensive use of antimicrobial agents in human and veterinary medicine, residues of various antimicrobials get into wastewater and, subsequently, surface water. On the one hand, a combination of processes in wastewater treatment plants aims to eliminate chemical and biological pollutants; on the other hand, this environment may create conditions suitable for the horizontal transfer of resistance genes and potential selection of antibiotic-resistant bacteria. Wastewater and surface water samples (Morava River) were analyzed to determine the concentrations of 10 antibiotics and identify those exceeding so-called predicted no-effect environmental concentrations (PNECs). This study revealed that residues of five of the tested antimicrobials, namely ampicillin, clindamycin, tetracycline, tigecycline and vancomycin, in wastewater samples exceeded the PNEC. Vancomycin concentrations were analyzed with respect to the detected strains of vancomycin-resistant enterococci (VRE), in which the presence of resistance genes, virulence factors and potential relationship were analyzed. VRE were detected in 16 wastewater samples (11%) and two surface water samples (6%). The PNEC of vancomycin was exceed in 16% of the samples. Since the detected VRE did not correlate with the vancomycin concentrations, no direct relationship was confirmed between the residues of this antimicrobials and the presence of the resistant strains.

Prescribing Pattern of Antibiotics Using WHO Prescribing Indicators Among Inpatients in Ethiopia: A Need for Antibiotic Stewardship Program

Background

Irrational prescribing of antibiotics is a universal public health problem, leading to antibiotic resistance. Understanding the prescribing pattern of antibiotics is crucial to tackling irrational prescription. Yet, comprehensive studies regarding the prescribing pattern of antibiotics among inpatients and the need for an Antibiotic Stewardship Program (ASP) are lacking in Ethiopia. This study aimed to evaluate prescribing patterns of antibiotics and the need for an ASP.

Methods

A hospital-based prospective observational study was carried out from February 2019 to December 2019. This study was conducted among patients admitted to Aksum University Comprehensive Specialized Hospital, Ethiopia. Data were collected using a data abstraction format generated by World Health Organization (WHO) prescribing indicators. Data analysis was carried out using SPSS version 25.0.

Results

A total of 1653 antibiotics were prescribed for 822 inpatients. Overall, 52.3% of patients had at least one oral and/or injectable antibiotic prescribed, for a mean duration of 4.2 (SD=2.3) days. The average number of prescribed antibiotics per patient was 2.01 (SD=1.9). The majority (97.6%) of antibiotics were prescribed by their generic name, and all prescribed antibiotics were from the national Essential Medicine List (EML). Frequently prescribed injectable and oral antibiotics were ceftriaxone (24.5%) and azithromycin (12.9%), respectively. Culture and sensitivity testing were not performed in any of the cases. During the study period, 65.2% of key antibiotics were available in stock.

Conclusion

In this study, more than half of patients were on at least one antibiotic, and all antibiotics were prescribed from the national EML. However, all antibiotics were prescribed empirically. This result shows that the prescribing pattern of antibiotics in the hospital deviates from and is non-compliant with the standard endorsed by WHO. This study provides evidence for the necessity and a way forward for the establishment of an ASP in the hospital that may help to introduce the prescribing of antibiotics with the aid of culture and sensitivity tests, and to develop institutional guidelines.