Antibiotic resistance assessment and multi-drug efflux pumps of Enterococcus faecium isolated from clinical specimens.

INTRODUCTION: Enterococcus faecium is a major cause of community and hospital-acquired infections. Due to limited options for infection with fluoroquinolones-resistant Enterococci, novel therapeutics are urgently needed. Efflux pumps are contributed to fluoroquinolones resistance phenotype in this bacterium and novel inhibitors that target these efflux pumps could be effective in patients. In this research, the possible synergistic effect of an efflux pump inhibitor (EPI), thioridazine, with ciprofloxacin was investigated against clinical isolates of E. faecium. METHODOLOGY: A total of 88 isolates of E. faecium from clinical specimens were studied from August 2017 to September 2018. Conventional phenotypic and molecular methods characterized all the isolates. Standard susceptibility tests and molecular assays determined the antibiotic resistance profiles and the frequency of efflux pump genes. Minimum inhibitory concentrations (MICs) to ciprofloxacin (CIP) in the presence and absence of thioridazine were measured by the micro-broth dilution method. RESULTS: The highest antibiotic resistance rate among E. faecium isolates was related to ciprofloxacin (96.8%), levofloxacin (94.3%), and imipenem (90.9%), respectively. The highest frequency of efflux pump determinants was related to efmA (60, 68%), followed by emeA (48, 54.5%), and efrA and/or efrB genes (45, 51%). The efflux pump inhibitor showed ≥ 2-fold decrease in the MIC value of ciprofloxacin in 48.2% of the isolates. CONCLUSIONS: Efflux pump inhibitor genes efrAB, efmA, and emeA are common among the E. faecium clinical isolates. Our results supported the administration of thioridazine, as an efflux pump inhibitor, in fluoroquinolone-resistant E. faecium infections due to its synergistic effect with CIP.

Genetic relatedness of the Enterococcus faecalis isolates in stool and urine samples of patients with community-acquired urinary tract infection.

BACKGROUND: Community-acquired urinary tract infection (CA-UTI) could be caused by endogenous or exogenous routes. To show this relationship, we investigated molecular fingerprints and genotypes of paired Enterococcus faecalis isolated from the urine of symptomatic patients and their fecal samples. RESULTS: Out of the studied patients, 63 pairs of E. faecalis isolates were obtained simultaneously from their urine and feces samples. All the strains were sensitive to vancomycin, linezolid, nitrofurantoin, and daptomycin (MIC value: ≤ 4 µg/ml), while resistance to tetracycline (urine: 88.9%; stool: 76.2%) and minocycline (urine: 87.3%, stool: 71.4%) was detected in most of them. The most common detected virulence genes were included efbA, ace, and gelE. RAPD-PCR and PFGE analyses showed the same patterns of molecular fingerprints between paired of the isolates in 26.9% and 15.8% of the patients, respectively. CONCLUSIONS: Similarity of E. faecalis strains between the urine and feces samples confirmed the occurrence of endogenous infection via contamination with colonized bacteria in the intestinal tract. Carriage of a complete virulence genotype in the responsible strains was statistically in correlation with endogenous UTI, which shows their possible involvement in pathogenicity of uropathogenic E. faecalis strains.

Association Between Urinary Tract Infection in the First Trimester and Risk of Preeclampsia: A Case-Control Study.

BACKGROUND: Urinary tract infection (UTI) is a common clinical problem during pregnancy that can have serious consequences for the mother and fetus. Some studies have suggested that UTI can trigger or aggravate preeclampsia. The present study aimed to investigate the association between urinary tract infection in the first trimester and the risk of preeclampsia in pregnant women referring to Bahar hospital of Shahroud. PATIENTS AND METHODS: In this case-control study, 92 pregnant women with a diagnosis of preeclampsia were selected as cases, and for comparison 92 pregnant women were selected as control. History of previous UTI in the first trimester was assessed as a risk factor. Data were analyzed using SPSS 16 software and related statistical tests such as mean and standard deviation, chi-square, and independent t-test. RESULTS: In this study, the mean age of the patients was 28.6 ± 6.9 years that no significant differences were found between the two groups. It was also found that 37 (40.2%) patients in the case group and 29 (31.5%) patients in the control group had a UTI which was significantly (p<0.043) higher in the case group. Also, in the multivariate regression model, UTI was significantly associated with preeclampsia (p<0.048), so that UTI increases the risk of preeclampsia (OR=1.86). CONCLUSION: The results of this study showed UTI during the first trimester of pregnancy is associated with the risk of preeclampsia. Therefore, controlling and treatment of urinary infections can reduce the risk of preeclampsia in the later months.

First detection of efrAB, an ABC multidrug efflux pump in Enterococcus faecalis in Tehran, Iran.

Enterococcus faecalis is one of the most significant pathogen in both nosocomial and community-acquired infections. Reduced susceptibility to antibiotics is in part due to efflux pumps. This study was conducted on 80 isolates of E. faecalis isolated from outpatients with urinary tract infection during a period of 1 year from April 2014 to April 2015. The antibiotic susceptibility patterns of isolates were determined by the disk diffusion method and presence of efrA and efrB genes was detected by PCR and sequencing. Minimum inhibitory concentrations (MICs) to ciprofloxacin (CIP) were measured with and without carbonyl cyanide 3-chlorophenylhydrazone (CCCP) by broth microdilution. The highest resistance rate was observed to erythromycin (83.3%) and the prevalence of efrA and efrB genes in all E. faecalis isolates was 100%. This study showed that 9 out of 13 (69.2%) ciprofloxacin-resistant isolates became less resistant at least fourfolds to CIP in the presence of efflux pump inhibitor. Our result showed that CCCP as an efflux inhibitor can increase effect of CIP as an efficient antibiotic and it is suggested that efrAB efflux pumps are involved in resistance to fluoroquinolone.

Prevalence of virulence determinants and antibiotic resistance patterns of Enterococcus faecalis strains in patients with community-acquired urinary tract infections in Iran.

The aim of this study was to characterize virulence factors and antibiotic resistance patterns in E. faecalis strains obtained from community-acquired urinary tract infections. A total of 70 E. faecalis isolates from Labbafinejad Hospital in Tehran were collected. Antibiotic resistance and virulence determinants were examined by phenotypic and molecular methods. Among 70 E. faecalis isolates, efba (97.1%), ace (95.7%), and gelE (94.3%) were the most prevalent virulence genes. The most common antibiotic resistance pattern was tetracycline (88.6%) and minocycline (87.1%). Multi-drug resistant phenotype was detected among 10% of them. Our results showed capability of E. faecalis strains for infection of the urinary tract in community. Involvement of virulence determinants in the pathogenesis of community acquired E. faecalis strains was proposed due to their high prevalence rates. Food producing animals were proposed as their environmental reservoirs, due to dominance of tetracycline resistance phenotype among them.

Detection of B. fragilis group and diversity of bft enterotoxin and antibiotic resistance markers cepA, cfiA and nim among intestinal Bacteroides fragilis strains in patients with inflammatory bowel disease.

We compared frequency of the members of B. fragilis group in 100 and 20 colon biopsy specimens of inflammatory bowel disease (IBD) and non-IBD patients. Agar dilution and PCR were orderly used to detect minimal inhibitory concentration of ampicillin, imipenem, and metronidazole, and carriage of related resistance genes cepA, cfi, and nim. B. fragilis group was detected in 38% of IBD (UC: 36/89; CD:1/11) and 25% (5/20) of non-IBD patients. While B. vulgatus (UC: 20/36, CD: 1/2, control: 1/6); B. fragilis (UC: 18/36, CD: 1/2, control: 5/6); B. ovatus (UC: 2/36); B. caccae (UC: 1/36); and B. eggerthii (UC: 1/36) were characterized, colonization of B. thetaiotamicron, B. merdae, B. distasonis, B. stercoris and B. dorei species was not detected in these specimens. Co-existence of B. fragilis + B. vulgatus (5 patients) and B. vulgatus + B. caccae (1 patient) was detected just in UC patients. bft was detected among 31.5% (6/19) of B. fragilis strains in the IBD and 40% (2/5) in the non-IBD groups. Nearly, 73.6% of the strains from the patient group and 80% in control group harbored cepA; 31.5% and 20% in the patients and control groups harbored cfiA, and none of them harbored nim determinant. Co-occurrence of the cepA and cfiA was orderly detected in 10.5% (2/19) and 20% (1/5) of the strains in these groups. The resistance rates were detected as 95.8% (23/24 (to ampicillin (MIC range of ≤0.5-≥16 µg/ml), 0% to metronidazole and 29.1% to imipenem (7/24, MIC range ≤4-32 µg/ml). Nearly 25% (6/24) of the strains were resistant to ampicillin and imipenem, simultaneously. No statistically significant difference was detected between the IBD and control groups for drug resistance phenotypes. Statistical analysis showed significant associations between resistance to ampicillin or imipenem and carriage of cepA or cfiA, respectively (p value = 0.0007). PCR results on the extracted plasmids confirmed their roles in carriage of cfiA and cepA. These data provide guide for antibiotic therapy and highlights wide distribution of ß-lactam resistant B. fragilis strains in patients with IBD and non-IBD intestinal disorders.

Genotyping, antimicrobial resistance and virulence factor gene profiles of vancomycin resistance Enterococcus faecalis isolated from blood culture.

BACKGROUND: Enterococcus spp. is the common of intestinal micro flora in humans but nowadays this gram-positive bacterium causes the variety of nosocomial infections. Resistance to antibiotic and also, presence of different virulence genes in the enterococcus spp. can change it to problematic microorganisms in the health care centers. The aim of this study was determined the genotyping, antimicrobial resistance and virulence factor gene profiles of vancomycin resistance Enterococcus faecalis isolated from blood culture. METHODS: In this study, enterococcus isolated from BACTEC was collected and antibiotic susceptibility testing was done according to CLSI recommendation. Important virulence genes and vancomyci resistance genes were detected by PCR and molecular typing was performed by RAPD PCR assay. RESULTS: Nine enterococcus collected from 194 positive BACTEC and seven out of nine were vancomycin-resistant enterococcus (VRE). vanA gene observed in all VRE and none of strains carried vanB and vanC genes. efbaA and gelE virulence factors have been detected in all strains. ace, esp, and cyl virulence factors genes harbored in two, seven and eight isolates respectively. asaI was not detected in any strains. All seven VRE isolates were related to the one specific molecular type and two different molecular types observed in the two vancomycin susceptible enterococci according to molecular epidemiology results. CONCLUSION: More prevalence of the VRE in enterococcus isolated from BACTEC is so important and on the other hand high genetic relationship in the isolated VRE can be very considerable for nosocomial infection committee in the hospital.

The role of the intensive care unit environment and health-care workers in the transmission of bacteria associated with hospital acquired infections.

The goal of this study was to attempt to determine the rate of contamination of health-care workers' (HCWs) hands and environmental surfaces in intensive care units (ICU) by the main bacteria associated with hospital acquired infections (HAIs) in Tehran, Iran. A total of 605 and 762 swab samples were obtained from six ICU environments and HCWs' hands. Identification of the bacterial isolates was performed according to standard biochemical methods, and their antimicrobial susceptibility was determined based on the guidelines recommended by clinical and laboratory standards institute (CLSI). The homology of the resistance patterns was assessed by the NTSYSsp software. The most frequent bacteria on the HCWs' hands and in the environmental samples were Acinetobacter baumannii (1.4% and 16.5%, respectively), Staphylococcus aureus (5.9% and 8.1%, respectively), S. epidermidis (20.9% and 18.7%, respectively), and Enterococcus spp. (1% and 1.3%, respectively). Patients' oxygen masks, ventilators, and bed linens were the most contaminated sites. Nurses' aides and housekeepers were the most contaminated staff. Imipenem resistant A. baumannii (94% and 54.5%), methicillin-resistant S. aureus (MRSAs, 59.6% and 67.3%), and vancomycin resistant Enterococci (VREs, 0% and 25%) were detected on the hands of ICU staff and the environmental samples, respectively. Different isolates of S. aureus and Enterococcus spp. showed significant homology in these samples. These results showed contamination of the ICU environments and HCWs with important bacterial pathogens that are the main risk factors for HAIs in the studied hospitals.

Device-associated infection rates and bacterial resistance in six academic teaching hospitals of Iran: Findings from the International Nocosomial Infection Control Consortium (INICC).

Device-associated health care-acquired infections (DA-HAIs) pose a threat to patient safety, particularly in the intensive care unit (ICU). However, few data regarding DA-HAI rates and their associated bacterial resistance in ICUs from Iran are available. A DA-HAI surveillance study was conducted in six adult and pediatric ICUs in academic teaching hospitals in Tehran using CDC/NHSN definitions. We collected prospective data regarding device use, DA-HAI rates, and lengths of stay from 2584 patients, 16,796 bed-days from one adult ICU, and bacterial profiles and bacterial resistance from six ICUs. Among the DA-HAIs, there were 5.84 central line-associated bloodstream infections (CLABs) per 1000 central line-days, 7.88 ventilator-associated pneumonias (VAPs) per 1000 mechanical ventilator-days and 8.99 catheter-associated urinary tract infections (CAUTIs) per 1000 urinary catheter-days. The device utilization ratios were 0.44 for central lines, 0.42 for mechanical ventilators and 1.0 for urinary catheters. The device utilization ratios of mechanical ventilators and urinary catheters were higher than those reported in the ICUs of the INICC and the CDC's NHSN reports, but central line use was lower. The DA-HAI rates in this study were higher than the CDC's NHSN report. However, compared with the INICC report, the VAP rate in our study was lower, while the CLAB rate was similar and the CAUTI rate was higher. Nearly 83% of the samples showed a mixed-type infection. The most frequent pathogens were Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa, followed by Klebsiella pneumoniae and Enterococcus spp. In the S. aureus isolates, 100% were resistant to oxacillin. Overall resistances of A. baumannii and K. pneumonia to imipenem were 70.5% and 76.7%, respectively. A multiple drug resistance phenotype was detected in 68.15% of the isolates. The DA-HAI rates in Iran were shown to be higher than the CDC-NHSN rates and similar to the INICC rates. Resistance to oxacillin and imipenem was higher as well. Comparing device use, DA-HAI rates, and bacterial resistance for the primary isolated bacteria indicated a direct association between urinary catheter use and the rates of CAUTI.