انتروکوک

Wastewater is one of the most dangerous and important sources of pathogens and their treatment does not always guarantee the elimination of pathogenic bacteria. Enterococci, as opportunistic pathogenic bacteria, fastidious and cause of nosocomial infections, have a wide environmental distribution and one of the routes of their transmission to humans is water and wastewater. The increasing rate of drug- resistance among bacteria indicates the need for investigation of novel antibacterial agents or their combination effects. The aim of this study was to investigate the effect of linezolid in combination with rifampin on the elimination of multidrug- resistant enterococci in two treatment plants in Golestan province. 

Enterococcus species from eighty samples were isolated from treatment plants in two cities of the Golestan Province (North of Iran) including Gorgan and Bandar-e Torkaman during January-June 2021. The isolates were identified based on the most probable number (MPN), filtration, microbiological tests and finally by using specific gene detection by ddlE primer with polymerase chain reaction. Kirby Bauer performed an antibiotic resistance pattern according to CLSI- 2020 guidelines for six classes of antibiotics. The minimum inhibitory concentration of linezolid was determined individually and by synergist effect with rifampin by broth microdilution method. 

After phenotypic and molecular diagnosis (PCR) of raw and treated wastewater samples, in 32 (40%) wastewater samples, enterococci species were identified and confirmed. Tetracycline was the least effective so, about 100% of Enterococcus faecalis and Enterococcus faecium isolates were resistant to it. The prevalence of linezolid-resistant E. faecalis was 11%. A total of 20 enterococcal isolates (62.5%) had multiple resistance. The concentration of linezolid in combination with rifampin, which inhibited 90% growth of the isolates (MIC90) was 1μg /ml, four-fold lower than linezolid alone (MIC90=4 μg/ml). In addition, none of the enterococci isolates showed resistance to the linezolid/rifampin combination (P=0.001).

The results of this research confirmed the presence of enterococci resistant to vancomycin and other antibiotics in the wastewater treatment plant samples in Golestan province. The favorable combination effect of linezolid and rifampin on the inhibition of multi-drug resistant isolates implies their synergy.

Vancomycin-resistant Enterococci are considered as a serious problem owing to limited selective therapies necessitating alternative antibiotic therapies. The aim of this study was to isolate and identify effective probiotics against vancomycin-resistant Enterococci strains and their biofilms.

In this experimental study, Enterococci samples were isolated from several hospitals in Isfahan and their vancomycin-resistant strains were selected by antibiotic susceptibility testing. The antimicrobial effect of various probiotic bacteria against them was investigated. After selecting the most effective probiotics, various tests including mortality time and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were performed. The inhibitory mechanism of these probiotics and the amount of lactic acid production as the main inhibitory mechanism were studied using high performance chromatography.

On total, 350 Enterococci samples were isolated, 46 of which were vancomycin resistant in which linezolid was among the few effective antibiotic. Two probiotic bacteria, Pediococcus acidilactici and Lactobacillus plantarum, were isolated which were effective against all vancomycin-resistant Enterococci and their biofilms. The lethal time of these two probiotics was 12 hours and the MIC and MBC were at concentrations of 0.5 µg/ml and 1 µg/ml respectively. Various tests on these two probiotics also showed no pathogenicity and no antibiotic resistance. The amount of lactic acid in Lactobacillus plantarum and Pediococcus acidilactici were 2.5 and 1.1 g per 100 ml respectively.

The optimal antimicrobial and antibiofilm properties of these two probiotics alongside producing high levels of lactic acid against all vancomycin resistant strains demonstrate their desirable and potential properties.

Water contamination of baths causes gastrointestinal, skin and fungal diseases due to pathogens. Therefore, this study was conducted to determine the microbial contamination of natural swimming places water in Behshahr.

The present descriptive study was performed in three natural swimming places. Nine-tube fermentation method was used to determine the bacterial contamination of coliforms, and membrane filtration method was used to measure enterococci. Pearson's correlation coefficient was used for data analysis. 

Total coliforms in 2 samples (22.22 %) were undesirable and in 7 samples (77.78 %) desirable; thermophilic coliforms in one sample (11.11 %) were undesirable and in 8 samples (88.89 %) desirable; and intestinal enterococci in one sample (11.11%) were undesirable and in 8 samples (88.89%) desirable. There was a significant relationship between total coliforms and fecal coliforms and total coliforms and intestinal enterococci (p = 0.001).

Totally, bacteriological contamination index was desirable in the investigated natural swimming places, but in a limited number of samples, the contamination indices were higher than the standard. Funding This study did not have any funds.

 None declared.

This project was not registered. How to cite this article: Amouei A I, Jafari Atrabi M , Fallah S H , Asgharnia H A, Aghalari Z. Survey of Microbial Contamination of Water in Natural Swimming Places of Behshahr in 2017: A Short Report. J Rafsanjan Univ Med Sci 2019; 18 (8): 839-48. [Farsi]

Hospital infections are one of the major problems in intensive care units and in many cases increases the mortality rate. A 68-year-old man is being treated after cervical vertebra fracture and fracture and is treated with linezolid following antibiotic resistance. Following the non-observance of the isolated contact points, this resistance was transferred to the patient's bed that was 76 years old and leads to his death In order to prevent hospital infection, proper hand washing is of great importance.

The water which is prepared for specific uses and has lost its quality is called wastewater. Wastewater of hospitals and health centers contains different pathogens that reveals the necessity of attention to this pollution sources. Therefore, this study was designed to evaluate the antibiotic resistance pattern of bacteria isolated from hospital wastewater treatment plant. In this descriptive study (in 2015), the samples of wastewater were collected from the hospital aeration ponds in different seasons. Samples were transferred to the laboratory under standard conditions. The bacteria count were performed by multiple tube test and were reported according to MPN (Most Probable Number) method. Microbial identification tests were performed according to conventional methods. The investigation of antibiotic resistance was performed using Kirby– Bauer standard technique according to method of Clinical and Laboratory Standard Institute 2014 (CLSI). Data were analyzed by SPSS software. In this study, a total of 20 samples were collected in different seasons. Despite more cases of isolated coliforms, the count of enterococci was higher than that of the coliforms.The highest resistance to ceftazidim (100%) and trimethoprim (85%) was observed in Enterococcus and Coliforms, respectively.
The highestsusceptibility to meropenem, imipenem, gentamycin, and ceftazidim (100%) was observed in Pseudomonas. Also, in the spring and autumn, the antibiotic resistance was higher than in the other seasons. It is necessary to pay attention to the sources of contamination in order to prevent increasing the burden of contamination of highly resistant bacteria. In addition, it is necessary to conduct a national survey to determine phenotypic and genotypic resistance patterns of bacteria in Iran

Enterococcus spp. are predominant in the faecal microflora which enter the environment directly or through wastewater. These bacteria play an important role in the development of nosocomial infections due to their ability to acquire resistance genes and their transmission to other bacteria, particularly Staphylococcus aureus. The aim of this study was to identify the prevalence of vancomycin-resistant enterococci (VRE) and to detect van A, van B and van C1/C2 genes in VRE strain isolated from environmental samples of the in southern Fars province.
This cross-sectional study was carried out on 155 Enterococcus spp isolates collected from environmental samples (hospital wastewaters and surface waters) in different areas of Larestan and Jahrom cities. Isolates were identified and confirmed as Enterococcus spp. using the membrane filtration method, selective growth on Kenner Fecal Streptococcus Agar (KF) medium and biochemical tests. The disk diffusion test and Macro Broth dilution method based on CLSI guidelines were used to determine antimicrobial susceptibility against conventional antibiotics and vancomycin and to measure the minimum inhibitory concentration (MIC), respectively. Finally, the presence of van A, van B and van C1/C2 genes in VRE strains was determined by multiplex PCR technique.
Out of all of Enterococcus spp. isolates, 41 cases (26.45%) were belonged to E.faecalis, 6 cases (3.87%) to E.faecium and 108 cases (69.68%) to non-faecalis and non-faecium. In total, 46 isolates (29.67%) were resistant to vancomycin and 4 isolates showed MIC ≥128 μg/ml. Resistant to all types of antibiotics was observed in 4 isolates (8.70%). Further, 2 isolates (50%) had vanA gene and 2 isolates (50%) had vanB gene, but vanC1/C2 genes were detected in none of them.
The results indicated that the VRE strains are widespread in the studied area, therefore there is an urgent need for prudent use of vancomycin and implementation of control measures to prevent the environmental spread of VRE strains.

Enterococci is gram positive bacteria which is the inhabitants of gastrointestinal tract. Hospital infections and antibiotic resistance to enterococci is increased. This study was done to determine the molecular evaluation of vanA and vanB genes of enterococci isolates resistant to Vancomycin and Teicoplanin.
In this descriptive study, 113 isolates samples were collected and identified according to biochemical test and cultural characteristics in Ali ibn Abi Talib hospital in Zahedan, Iran. Antibiogram test was done to determine antibiotic resistance pattern. E-test strip was used to evaluate the minimum inhibitory of concentration (MIC). PCR was used to detect the vanA and vanB genotype in Vancomycin and Teicoplanin resistance enterococci.
92%, 6.2% and 1.8% of isolated samles collocted from urine, blood culture and pleura fluid, respectively. According to phenotype, 18.6% and 17.69% were resistance to Vancomycin and Teicoplanin, respectively. Resistance was observed in strains of Enterococcus faecalis and Enterococcus faecium. VanA genotype was seen in all of the resistance isolated species.
This study showed that strains of Enterococcus faecalis and Enterococcus faecium have more antibiotic resistance to the Vancomycin and Teicoplanin, morever vanA genotype precence in all of resistance isolated samples.

Enterococci, gram-positive cocci, are important human pathogens in both community and hospital-acquired infections. Also, they are intrinsically resistant to many commonly used antimicrobial agents. The purpose of this study was to investigate antibiotic resistance profiles of Enterococci isolated from referred patients in Qaem teaching hospital.
A total of 110 isolates of Enterococci were collected from Qaem teaching hospital affiliated to Mashhad University of Medical Sciences during April to October 2014. Then the modified disk diffusion method (MDDM) was used for identifying the susceptibility of the isolates to 10 selected antibiotics.
Resistance of Enterococcus strains to vancomycin, penicillin, ceftriaxone, erythromycin, ampicillin, amoxicillin, ciprofloxacin, gentamicin, nalidixic acid and co-trimoxazole was 5.4%, 54.5%, 70%, 79%, 41.8%, 35.5%, 71.8%, 65.4%, 89% and 71.8% respectively. In this study, 92 isolates were obtained from urine(83.6%) and 18 isolates(16.3%) were from various samples (7 isolates from blood, 1 isolate from cerebrospinal fluid, 3 isolates from scar and 7 isolates from secretions). Moreover, 51% of bacteriological isolates were obtained from men and 46% were from women.
Based on the results of this study, a significant percentage of Enterococcus strains are resistant to ceftriaxone, erythromycin, ciprofloxacin, nalidixic acid and co-trimoxazole. Therefore, there is a need for appropriate therapeutic strategies to control and prevent the spread of resistant strains.

Enterococci are Gram-positive cocci that are found in abundance in the environment. The ability of these bacteria for long-term survival in hospital environment, increases the chance of patients for infections caused by this bacterium. Therefore, identification of possible sources and reservoirs is helpful in identifying the potential sources in sudden outbreaks. The current study was conducted to determine the prevalence rate and antibiotic resistance pattern in environmental Enterococcus isolates collected from delivery room environment of Alzahra and Izadi university hospitals in Qom.
In this descriptive cross-sectional study, over a period of 3 month, sampling was performed using swabbing method from delivery rooms of alzahra and izadi hospitals in Qom, and were examined for the presence of Enterococci. After isolation, Enterococcus species were examined using different biochemical tests, and the antibiotic resistance pattern in the environmental was assessed according to disk-diffusion test according to Clinical and Laboratory Standards Institute (CLSI) standards. The data were described by frequency tables.
In this study, out of 216 obtained isolates, 7(3.2%) belonged to Enterococcus genus. 4(57%) out of 7 Enterococcus strains isolated from surfaces of delivery room, had multiple resistances based on antibiotic sensitivity test using antiobiogram test.
According to increasing growth of nosocomial infection caused by resistant strains of Enterococcus spp. and their spread in hospital environment, use of infection control measures are necessary to eliminate the potential sources and prevent the infection.

Enterococci lead to many problems in terms of treatment failure and mortality in patients especially due to antibacterial resistance. Identification of antibiotic resistance in community is of extreme importance to prevent failures particularly in the treatment of infections. Therefore, this study intended to screen antibiotic-resistant enterococci samples from patients. Samples were collected from feces and blood of patients hospitalized over a period of 9 months from July 2013 to March 2014 in Vali-e Asr and Mousavi hospitals. Diagnostic tests such as growth in the presence of bile esculin agar and NaCl 6.5% as well as catalase and Gram staining were performed to verify the samples. Agar disk diffusion method for antibiotic susceptibility testing and microtitre plate assay was performed to evaluate the MIC of vancomycin. Among the tested antibiotics, ciprofloxacin showed the highest and teicoplanin as well as vancomycin exhibited the least antibiotic resistance. Interestingly, vancomycin minimum inhibitory concentration was determined 5 to 50 &mug/ml. In our study, isolated enterococci from the hospitalized patients showed relatively high resistance to majority of antibiotics. Meanwhile, antibiotic resistance to teicoplanin and vancomycin were acceptable in comparison to other similar studies.

Enterococci are among the normal microbial flora in human and animals digestive tract. The nosocomial pathogenicity of enterococci has emerged in recent years and has caused great concern due to developing resistance to many antimicrobial agents. The aim of this study was to investigate and identify the prevalence of VRE (vancomycin resistant enterococcus) within Enterococci isolates obtained from different parts of the hospital. Putative Enterococci (n=120) were isolated on Membrane Filter Enterococcus Selective Agar Medium and supplemented with 2, 4 and 8 µgr/ml vancomycin in medical samples. A total isolates passed the standard biochemistry tests for the genus and species as well as their specific primers. The antibiotic susceptibility was determined by the disc diffusion method for 8 antibiotics. Microbiologically-influenced corrosion (MIC) of vancomycin was also done using Agar-dilution assay by CLSI recommendations. Results showed that 38 and 84 of the isolates were E. faecium and E.faecalis, respectively. According to antimicrobial susceptibility tests 45, 88, 103, 42, 83, 73, 54 and 95 of the isolates were resistant to vancomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, penicillin, ampicillin and erythromycin, respectively. MIC test on 70% of the isolates was>256 µgr/ml. Despite the fact that the prevalence of VRE strains belongs to two species, E. faecium had high resistance to a broad range of antibiotics. The results of this study indicate the important role of medical samples as reservoirs of resistance elements. Early detection of VRE with their virulence trait will help in preventing the spread of vancomycin resistant enterococcus species and urgent infection control is required in hospital setting

Due to the unique absorption and antibacterial properties of nanoparticles, their use in water and wastewater treatment to remove bacteria is spreading. This research aimed to study the effect of silver nanoparticles in the removal of Enterococcus faecalis isolated from industrial sewage. after preliminary studies, field studies including sampling of industrial wastewater was conducted. First, Fecal Coliform, total coliform and Enterococcus faecalis of industrial Sewage were measured by standard methods of microbiology, then the effect of concentrations of 500, 250, 125, 62.5, 31.25, 15.62, 7.81, and 3. 9 PPM of isolated nanoparticles serial dilution method on Enterococcus faecalis and standard (PTCC 1339) was determined. Next, and the turbidity of tube (OD), which represents growth of bacteria, was read at 600 nm with a spectrophotometer. After that, all tubes were cultured on solid medium and the results were analyzed using SPSS 22. fecal and total coliform contamination of industrial Sewage from slaughter and textile plant were approved and Enterococcus faecalis was isolated. The growth of isolates and standard bacteria was not controlled by any of these concentrations. None of the concentrations was able to remove the bacteria but the increase of concentration led to higher effect of nanoparticles, and in accordance with the type of bacteria, it was different, but the difference was not statistically significant. Although silver nanoparticles, according to the concentration, affect the Streptococcus faecalis, they cannot completely remove bacteria. Therefore, the economic factors and other involved factors need to be considered in the application of nanoparticles.

Background and Enterococci are important agents of endocarditis and urinary tract infections. They acquire resistance against antimicrobial agents which causes difficulty in their treatment. This study aimed to determine the antimicrobial susceptibility of strains resistant to vancomycin and identification of resistance genes vanA and vanB Enterococcus strains isolated from teaching hospitals in 2014. Hundred and fifty isolates of Enterococcus were isolated from hospitals and the genus and species composition were identified using different biochemical methods. Antibiogram tests were also conducted. The minimum inhibitory concentration was conducted applying broth micro dilution. Finally the strains containing vanA and VanB genes were identified. The antibiogram test showed 10 strains with VanA and VanB phenotype. All strains were resistant to ciprofloxacin. VanA and VanB genes were detected in all 10 isolates of vanA phenotype and two strains of vanB phenotype. VanA and VanB genes were proliferated by PCR in two strains of the10 strains that were VanA phenotype. Among Enterococcus species E. faecium and E. faecalis isolates were detected in teaching hospitals. The highest rate of resistance was to erythromycin and tetracycline and the lowest resistance rate was to vancomycin.

Enterococci are normal flora of human body and considered as the third leading cause of nosocomial infections. The aim of this study was to determine drug resistance of Enterococcus species through biochemical methods. One hundred twenty-eight of enterococcus suspected samples were isolated from gorgan and gonbad’s hospitals from April to June, 2013. The samples were cultured on blood agar, chrome-agar, EMB agar and some special cultures of isolation of Enterococcus species. Suspension of bacteria was grown in Mueller Hinton agar and the inhibition zone diameter was determined by disk antibiogram. Of 128 samples, 109(85.15%) were enterococci faecalis and 19 (14.85%) Enterococcus Faecium. In all of 128 cases, eight showed resistance to amoxicillin, ten to ampicillin, five to gentamicin, five to ciprofloxacin, six to chloramphenicol, four to cephalexin and one to vancomycin. It seems to be necessary to use drug sensitivity test for having appropriate treatment and preventing from resistance strains.

Enterococci have been recognized as clinically important pathogens. Among more than one dozen species of Enterococcus species, Enterococcus faecalis and Enterococcus faecium are major pathogens. Vancomycin resistant Enterococci (VRE) strains have been spread worldwide among inpatients and outpatients. This study was designed to study phenotypic and genotypic characteristics of VRE isolates from inpatients and outpatients. Of 193 enterococci isolates, 178 strains were identified as E. faecalis and as 15 E.faecium. Out of 193 isolates strains of enterococci, 22 were detected as VRE. All of these strains were isolated from fecal (6 starins) or clinical samples (16) of hospitalized patients. The PCR revealed VanA genotype in 10 E. faecium and 2 E. faecalis strains, whereas VanB genotype was detected in 5 E.faecium and 5 E.feacalis strains. No VanC genotype was detected among VRE strains. Due to limited published studies in Iran for VRE strains, we are not able tot compare our results with other studies, but our findings showed that VRE strains were isolated from normal flora and clinical samples, on the other hand the VanA genotype is more than VanB among VRE strains.

Enterococci are among the most important causes of urinary tract infections. The aim of this study was to assess the frequency of erm A, B, and C genes in erythromycin-resistant Enterococci isolated from the clinical samples of inpatients of university teaching hospitals in Qazvin and Tehran. From 2012 to 2013, a total of 165 samples of enterococci were isolated from the clinical samples of inpatients. Susceptibility to erythromycin in enterococci isolates was performed by agar dilution and disk diffusion methods according to the Clinical and Laboratory Standards Institute (CLSI) guideline. Erythromycin resistance genes (ermA, B, and C) were identified by PCR. Out of 165 clinical isolates of enterococci, 142 (86%) isolates were Enterococcus faecalis and 23 (13.9%) isolates Enterococcus faecium. The results of susceptibility test showed that 158 (% 95) isolates were resistant or with intermediate sensitivity to erythromycin. There was a good correlation between the results of disk diffusion and agar dilution methods. Of total samples, 147 (89%) isolates were resistant to erythromycin (MIC≥8 µg/ml), 11 (6.6%) isolates with intermediate sensitivity (MIC 1-4 µg/ml), and 7 (4.2%) isolates with complete sensitivity to erythromycin (MIC ≤ 0.5 µg/ml). The results of this study showed high prevalence of ermA, B, and C genes in erythromycin-resistant strains with ermB asthe most common resistance gene among these isolates.

Attention has largely been focused on appearance of multiple drug resistance enterococci in the last 20 years. One of the methods to overcome this problem is to combine different antibiotics in order to increase antimicrobial activity and reduce toxicity. The combination of fluor quinolones with other antibiotics has been widely investigated. The aim of this study was to investigate the synergistic effect of ciprofloxacin in several antibiotics Beta-lactam (piperacillin, ceftazidime and imipenem) on isolated enterococci. In this cross sectional study, 67 Streptococci strains were isolated from clinical samples from March to September 2012. The serial broth dilution method in test tubes was used for the MIC, and the check board Format was used for the synergistic effect of ciprofloxacin with Beta-lactam antibiotics. The synergistic effect was determined with four- fold reduction of initial MIC. Totally, 67 strains of Streptococci were used, in which 50 strains (74.6%) were enterococci, 6(9%) were group B streptococcus, 5(7.5%) were non-group A streptococci, 2 (3%) were pneumococci, and 2 were strains of alpha streptococci (3%), respectively. All results were determined by the MIC and MBC of each antibiotic individually and also in combination with ciprofloxacin. The effect of ciprofloxacin on other antibiotics was indifferent, and the synergistic effect was not observed.

Background and Resistance to choice antibiotics is serious and focus of concern. Therefore، the current study was done to identify the enterococcus resistance pattern to Linezolid- choice antibiotic، which has not yet been used in the country. This descriptive study was a laboratory research done on 100 stool samples gathered from hospitalized patients of Shahid Beheshti Hospital، Kashan، 2012. The samples were transferred to the university microbiology laboratory in transport media and the entrococcus identity was established through biochemical tests. Then Linezolid and Vancomycin antibiogram was recorded by means of Disk Diffusion method. On the other hand، Minimum Inhibition Concentration (MIC) for Vancomycine was measured by E-test method. Finally، the results were analyzed by means of SPSS software- Chi square test، and paired T-test. The mean age was 52. 26±18. 29 years old. Forty eight subjects were females (48%) and the rest were males. Thirty four subjects were colonized with Vancomycine Resistant entrococci and 33 others with Linezolid Resistant entrococci. Using the E-test method، 73 strains were sensitive to vancomycine (MIC≤4g/ml)، 27 resistant (MIC>33g/ml)، and none was intermediate. Using antibiotic was one of the most important risk factors for vancomycine resistance in enterococci (P<0. 05). The duration of antibiotic use with Linezoid in the past was the only effective factor in resistance (P<0. 05). The resistance rate of enterococci was 33%، without any history of linezolid use in the past، this can conclude that sort of cross resistance to both vancomycine and linezolid، synchronically; that suggests the necessity of future studies about genome basics of the issue.