Evaluation of the Antimicrobial Resistance of Klebsiella pneumoniae by E-Test Method in Khatam_ol_Anbia Hospital, Tehran, Iran, during 2015

Reports of the development of antimicrobial resistance by Bordetella pertussis to macrolides in the United States and Taiwan, together with a recent increase in pertussis notifications and laboratory-confirmed cases in England and Wales in 2008, prompted the examination of historical and recent clinical isolates from patients for evidence of such resistance in our collection. Isolates submitted to our laboratory as part of the enhanced surveillance scheme for pertussis, from 2001 to 2009, were tested against three agents, erythromycin, clarithromycin and azithromycin, by the Etest (bioMérieux) method. All isolates (n = 583) were fully susceptible to all three agents tested (minimum inhibitory concentrations [MICs] <or=0.125 microg/ml). All but one strain (582/583) had MICs of <or=0.064 for all three agents. The control strain of B. pertussis A228 (from the Centers for Disease Control and Prevention [CDC], Atlanta, Georgia, USA) with a resistant phenotype had an MIC of >256 microg/ml. Although no evidence of resistance was found in the strains tested from the United Kingdom, screening for antimicrobial resistance of B. pertussis may be warranted in cases that are unresponsive to macrolide treatment and to provide early warning of such emergence in the future.

Accuracy of broth microdilution and E test methods for detecting chloramphenicol acetyl transferase mediated resistance in Streptococcus pneumoniae: Geographic variations in the prevalence of resistance in The SENTRY Antimicrobial Surveillance Program (1999)

Background: Over the past decade, Enterococci have been shown to be an important cause of nosocomial and community-acquired infections. Inappropriate use of antibiotics led to changes in the pattern of antibiotic resistances in Enterococcus species. Unfortunately, no study has been performed in Iran in recent years regarding the antimicrobial resistance of Enterococci using the E-test method as a base. We must gain sufficient knowledge about the regional antibiotic resistances related to Enterococcus so that we can monitor the prevalence and antimicrobial resistance of Enterococcus by administering appropriate treatments. Objectives: The objective of this study was to evaluate the antimicrobial susceptibility among Enterococcus species by the E-test method at Khatam-ol-Anbia hospital during 2013 - 2014. Patients and Methods: This descriptive cross-sectional study was carried out during 2013 - 2014. All clinical samples were collected from the intensive care unit (ICU) and general wards of Khatam-ol-Anbia hospital. All Enterococcus species were detected via biochemical testing. Antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined via disk diffusion and the E-test method. We used descriptive statistics to analyze the data. Results: A total of 53 Enterococci were isolated from clinical samples of blood, urine, wounds, sputum, and cerebrospinal fluid (CSF) over a two-year period from the ICU and general wards. The isolated Enterococcus species were 77.35% E. faecalis, 18.86% E. faecium, and 3.77% other species. Species evaluated by E-test were resistant to imipenem, ampicillin, co-trimoxazole, gentamicin, rifampicin, vancomycin, linezolid, and teicoplanin; 54%, 68%, 100%, 93.8%, 60.4%, 39.6%, 0%, and 29.2%, respectively. Among the strains of enterococci, 90.9% of E. faecium and 20% of E. faecalis species were resistant to vancomycin. Conclusions: According to these findings, antibiotic-resistance patterns have changed, and vancomycin resistance, especially among E. faecium, is rising because of nosocomial infections. Consequently, it has become a serious subject for patients admitted into a hospital.

Genomic characterisation of linezolid-resistant Enterococcus faecalis from Western Australia 2016–2021

Antimicrobial susceptibility testing is one of the most important tasks of clinical microbiology laboratories. This study was performed to compare accuracy of susceptibility testing carried out by disk diffusion method and E-test minimal inhibitory concentration (MIC) for detection antimicrobial resistance among three prevalent gram-negative organism isolated in an Iranian hospital . These organisms included Pseudomonas aeroginosa, Acenitobacter bumannii, and Klebsiella pneumoniaew which isolated from different Baquiatalah hospital wards .Disk diffusion method were carried out initially in Baqyatalah hospital microbiology laboratory. All isolates were sent to Iranian reference microbiology laboratory for detection of MIC by E-test method. Of 100 isolates, 52 isolates were Acinetobacter bumannii, 32 Pseudomonas aeroginosa and 16 Klebsiella pneumonia. All isolated strains were resistant to ciprofloxacin, imipenem, and amikacin by disk diffusion method. However there were significant differences compared with E-test method. Many strains were susceptible to above mentioned antibiotics by E-test method .Our study revealed that there was a controversy results between disk diffusion method and MIC determination technique by E-test. It may be due to lack of suitable internal quality control as well as poor quality of commercially provided disks in our country.

Urinary Tract Infections (UTIs) are of the most common bacterial diseases worldwide. We investigate the antibiotic susceptibility patterns of Escherichia coli (E. coli) strains isolated from pediatric patients with community acquired urinary tract infection (UTI) to find a clinical guidance for choosing a right empirical antibiotic in these patients. In this cross sectional study, 100 urine specimens which were positive for E. coli had been investigated for antibiotics susceptibility pattern. The susceptibility to Co-trimoxazol (25μg), Amikacin (30μg), Ceftriaxone (30μg), Nalidixic Acid (30μg), Cefixime (5μg), and Nitrofurantoin (300μg) tested with Disk diffusion agar and MIC determined with the E-test. Mean age of patients was 38 Months. Girls had greater proportion than boys (74 versus 26%). In Disk diffusion method, 26% of the isolates were susceptible to cotrimoxazole. Susceptibility to amikacin, ceftriaxone, nitrofurantoin, nalidixic acid and cefixime was 94%, 66%, 97%, 62% and 52%, respectively. By E-Test method and according to CLSI criteria susceptibility for co-trimoxazol, amikacin, ceftriaxone and nalidixic acid was 37%, 97%, 67% and 50%, respectively. The highest percentage of agreement between Disk diffusion and E-Test method was found for amikacin (96%) and the lowest percentage for co-trimoxazole (89%). Treatment failure, prolonged or repeated hospitalization, increased costs of care, and increased mortality are some consequence of bacterial resistance in UTIs. Misuse of antibiotics in each geographic location directly affects antibiotic resistance pattern. In the treatment of UTI, proper selection of antimicrobial agents should be relevant to the bacterial susceptibility testing surveillance. According to our results, amikacin as an injectable drug and nitrofurantoin as an oral agent could be used as a drug of choice in our region for children with UTIs.

Detection of metallo β-lactamase production and antibiotic resistance with E-test method in pseudomonas, acinetobacter and klebsiella strains, in Turkey

Changing trends of antimicrobial susceptibility and resistance mechanisms to quinolones in typhoidal salmonellae isolated from India in last 5 years

BackgroundsNeisseria gonorrhoeae causes gonorrhea and poses public health problems, including antimicrobial resistance. Current data on gonorrhea in prenatal participants in the study area are required. Thus, we aimed to identify gonorrhea prevalence, antimicrobial resistance, and risk factors among antenatal care clinic visitors in northwestern Ethiopia.MethodsA cross-sectional study was conducted from March to August 2022 at the University of Gondar Comprehensive Specialized Hospital. We recruited 278 study participants using convenient sampling techniques. Sociodemographic, clinical and behavioral risk factors were recorded using pre-tested questionnaires. Endocervical swabs were collected by a physician, transported to the microbiology laboratory, immediately inoculated into modified Thayer-Martin medium, and it was incubated at 37 °C for 24–48 hours. Gram staining and biochemical tests were used to identify the organism. AMR testing was performed using disc diffusion and E-test methods. Data were entered in EPI-info version 7 and exported and analyzed in SPSS version 26. A p-value ≤0.05 was considered as statistically significant. Results were presented in words, tables and figure.ResultsOf 278 subjects enrolled, majority (44.6%) were 26–35 years, with a mean age of 29.9 (SD = ±7.2) years, 69.4% were urban residents, and 70.5% were married. Twenty-one (7.6%) participants had gonorrhea. Overall antimicrobial resistance ranged from 19 to 100%. High resistant to tetracycline (100%) and penicillin (85.7%) were observed by both tests. Ciprofloxacin resistance was 52.4% by disc diffusion and 85.7% by E-test. By E-test, all isolates were sensitive to ceftriaxone, cefixime, azithromycin and spectinomycin; however, 7 (33.3%), 9 (42.9%), 9 (42.9%) and 5 (23.8%) isolates showed resistant to these antibiotics with disk method. Prevalence of beta-lactamase producing Neisseria gonorrhoeae was 85.7%. Alcohol consumption (p = 0.032), condom-free sexual practice (p = 0.010), multiple sexual partners (p < 0.001), pelvic pain (p = 0.018), and dysuria (p = 0.021) revealed increased risk of infection.ConclusionsCompared with many previous studies in Ethiopia, we found high prevalence, antimicrobial resistance, and beta-lactamase-positive isolates. Multiple sexual partners, alcohol consumption, not using condom, pelvic pain and dysuria were predictors of this infection. Continuous large-scale monitoring of pathogen is essential for its prevention and control.

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a common serovar associated with non-typhoidal salmonellosis globally. However, there is insufficient data on molecular characterization of S. Typhimurium isolates from India. This study was undertaken to determine the antimicrobial resistance (AMR), plasmid, virulence profiles and molecular subtypes of S. Typhimurium Indian isolates (n = 70) of clinical and environmental origin isolated during 2010–2017. Antimicrobial susceptibility and minimum inhibitory concentrations were determined by disc diffusion and E-test methods respectively. Plasmid extraction was done following standard protocol. AMR genes, virulence genes and plasmid incompatibility types were detected by PCR; Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were used for molecular subtyping. Majority (57%) of the study isolates was pan susceptible; five AMR profiles were observed among the resistant (43%) isolates. AMR was significantly (p = 0.004) associated with extra-intestinal isolates than intestinal isolates.The class 1 integron and plasmid-mediated quinolone resistance genes (qnrB1, qnrS1) in the resistant isolates were transferable by conjugation. Plasmids (≥1) ranging from 1.9 to 254kb size and of IncFIIS and/or FIB type were found in most isolates. A total of 39 pulsotypes by PFGE and four sequence types by MLST like ST36 (55.7%), ST19 (32.9%), ST313 (10%) and ST213 (1.4%) were observed. ST36 and ST19 were found circulating in both clinical and environmental host, while ST313 isolates had an exclusive clinical origin. All ST19 isolates (100%) were drug-resistant, while isolates belonging to ST313 (100%), ST213 (100%) and ST36 (82%) were pan susceptible. The virulence plasmid (VP) genes (spvB- spvC) were present in all genotypes except ST36. The VP was significantly (p<0.001) associated with extra-intestinal than intestinal isolates. Some environmental and clinical isolates were clonal indicating their zoonotic transmission. Knowledge on the molecular subtypes and AMR profiles of locally prevalent Salmonella serotypes is important for effective control of spread of resistant organisms. The MLST of S. Typhimurium isolates and its association with AMR, virulence profiles was not reported earlier from India.

Staphylococci, mainly including Staphylococcus aureus and coagulase-negative staphylococci (CNS), are one of the most common pathogens causing bovine mastitis worldwide. In this study, we investigated the antimicrobial resistance and virulence profiles of staphylococci from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. Antimicrobial resistance was determined by disc diffusion combined with E-test method. Genes of antimicrobial resistance and virulence factors were determined by PCR. A total of 332 staphylococcal isolates were confirmed from 1,519 mastitic milk samples, including 172 S. aureus and 160 CNS isolates. Fifteen CNS species were identified, with S. chromogenes being the most frequent found (49.4%), followed by S. equorum (13.8%). Noticeably, 2 S. agnetis isolates were found among the CNS isolates. To our knowledge, this is the first report documenting the presence of S. agnetis from bovine mastitis in China. The S. aureus and CNS isolates showed high resistance against penicillin, followed by erythromycin and tetracycline. Multidrug resistance was found in 11.6 and 16.3% of the S. aureus and CNS isolates, respectively. Resistance to penicillin was attributed to the presence of blaZ, erythromycin resistance to ermC (alone or combined with ermB) and tetracycline resistance to tetK (alone or combined with tetM). Notably, one S. equorum isolate and one S. saprophyticus isolate were both methicillin-resistant and mecA positive. Additionally, all S. aureus isolates carried the adhesin genes fnbpA, clfA, clfB, and sdrC, and most of them contained cna and sdrE. Conversely, only a few of the CNS isolates carried clfA, cna, and fnbA. Regarding toxin genes, all S. aureus isolates harbored hlb, and most of them were hlg positive. The lukE-lukD, lukM, sec, sed, sei, sen, seo, tst, seg, seh, and sej were also detected with low frequencies. However, no toxin genes were observed in CNS isolates. This study reveals high species diversity of staphylococci from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. The findings for the genetic determinants of antimicrobial resistance and virulence factor provide valuable information for control and prevention of staphylococcal bovine mastitis.

BackgroundAntimicrobial-resistant strains of Streptococcus pneumoniae have become one of the greatest challenges to global public health today and inappropriate use of antibiotics and high level of antibiotic use is probably the main factor driving the emergence of resistance worldwide. The aim of this study is, therefore, to assess the antimicrobial resistance profiles and multidrug resistance patterns of S. pneumoniae isolates from patients suspected of pneumococcal infections in Ethiopia.MethodsA hospital-based prospective study was conducted from January 2018 to December 2019 at Addis Ababa city and Amhara National Region State Referral Hospitals. Antimicrobial resistance tests were performed from isolates of S. pneumoniae that were collected from pediatric and adult patients. Samples (cerebrospinal fluid, blood, sputum, eye discharge, ear discharge, and pleural and peritoneal fluids) from all collection sites were initially cultured on 5% sheep blood agar plates and incubated overnight at 37 °C in a 5% CO2 atmosphere. Streptococcus pneumoniae was identified and confirmed by typical colony morphology, alpha-hemolysis, Gram staining, optochin susceptibility, and bile solubility test. Drug resistance testing was performed using the E-test method according to recommendations of the Clinical and Laboratory Standards Institute.ResultsOf the 57 isolates, 17.5% were fully resistant to penicillin. The corresponding value for both cefotaxime and ceftriaxone was 1.8%. Resistance rates to erythromycin, clindamycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole were 59.6%, 17.5%, 38.6%, 17.5 and 24.6%, respectively. Multidrug resistance (MDR) was seen in 33.3% isolates. The most common pattern was co-resistance to penicillin, erythromycin, clindamycin, and tetracycline.ConclusionsMost S. pneumoniae isolates were susceptible to ceftriaxone and cefotaxime. Penicillin has been used as a drug of choice for treating S. pneumoniae infection. However, antimicrobial resistance including multidrug resistance was observed to several commonly used antibiotics including penicillin. Hence, it is important to periodically monitor the antimicrobial resistance patterns to select empirical treatments for better management of pneumococcal infection.

BackgroundGonorrhoea and widely spread antimicrobial resistance (AMR) in its etiological agent Neisseria gonorrhoeae are major public health concerns worldwide. Gonococcal AMR surveillance nationally and internationally, to identify emerging resistance and inform treatment guidelines, is imperative for public health purposes. In 2009, AMR surveillance was initiated in Belarus, Eastern Europe because no gonococcal AMR data had been available for at least two decades. Herein, the prevalence and trends of gonococcal AMR and molecular epidemiological characteristics of N. gonorrhoeae strains from 2010 to 2013 in Belarus, are described.MethodsN. gonorrhoeae isolates (n=193) obtained in the Mogilev (n=142), Minsk (n=36) and Vitebsk (n=15) regions of Belarus in 2010 (n=72), 2011 (n=6), 2012 (n=75) and 2013 (n=40) were analyzed in regards to AMR using the Etest method and for molecular epidemiology with N. gonorrhoeae multi-antigen sequence typing (NG-MAST).ResultsDuring 2010–2013, the proportions of resistant N. gonorrhoeae isolates were as follows: tetracycline 36%, ciprofloxacin 28%, penicillin G 9%, azithromycin 5%, and cefixime 0.5%. Only one (0.5%) β-lactamase producing isolate was detected. No isolates resistant to ceftriaxone and spectinomycin were identified. Overall, the resistance levels to tetracycline, ciprofloxacin and penicillin G were relatively stable. Interestingly, the level of resistance to azithromycin declined from 12% in 2010 to 0% in 2013 (P < 0.05). In total, 70 NG-MAST STs were identified. The predominant STs were ST1993 (n=53), ST807 (n=13), ST285 (n=8) and ST9735 (n=8). Many novel STs (n=43, 61%), representing 41% of all isolates, were found.ConclusionsDuring 2010–2013, the N. gonorrhoeae population in Belarus displayed high and relatively stable resistance levels to tetracycline, ciprofloxacin, and penicillin G, while the resistance to azithromycin declined. One isolate was resistant to cefixime, but no resistance to ceftriaxone or spectinomycin was found. The results of the present surveillance initiated in 2009 were also used to replace penicillin G with ceftriaxone (1 g single dose intramuscularly) as the first-line drug for empiric treatment of gonorrhoea in the national treatment guidelines in Belarus in late 2009. It is essential to further strengthen the surveillance of gonococcal AMR and ideally survey also treatment failures and molecular epidemiological genotypes in Belarus.

Extended-spectrum -lactamases (ESBLs) are plasmid encoded enzymes that confer resistance to -lactam antibiotics through the hydrolysis of the -lactam ring. ESBLs are distributed worldwide with an increasing incidence and prevalence in the Middle East due to the misuse of antibiotics and lack of coherent antimicrobial surveillance studies. The aim of study is to analyze molecularly the antimicrobial resistance mechanisms of 50 Escherichia coli and Klebsiella pneumoniae isolates from nosocomial infections in hospitalized patients in Oman. Screening for antimicrobial resistance (AR) and ESBL production was carried out with the disk diffusion and E-test methods following CLSI guidelines. ESBL producers were screened for blaCTX-M, blaSHV, and blaTEM resistance markers via PCR using gene-specific primers. All amplified PCR fragments will be sequenced to determine their allelic variants. In order to demonstrate the overall genotypic variation, Pulsed-Field Gel Electrophoresis (PFGE) analyses were done separately among all E. coli and K. pneumoniae isolates. According to the AR analysis, 82% (41/50) of isolates were determined to be ESBL producing bacteria. The percentages of isolates with genetic markers for blaCTX-M, blaSHV, and blaTEM were 73%, 24%, and 68%, respectively. Preliminary PFGE analyses demonstrated high level of variation among ESBL isolates compared to non-ESBL producers. Further surveillance studies are needed to describe better the AR situation in these hospitals in Oman. from 2009 American University in Cairo Research Conference Cairo, Egypt. 5 April 2009

Helicobacter pylori plays a significant role in gastritis and ulcers. It is a carcinogen as defined by the WHO, and infection can result in adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. In Canada, rates of antimicrobial resistance are relatively unknown, with very few studies conducted in the past 15 years. To examine rates of resistance in Sudbury, Ontario, compare antimicrobial susceptibility methods and attempt to determine the molecular basis of antibiotic resistance. Patients attending scheduled visits at Health Sciences North (Sudbury, Ontario) provided gastric biopsy samples on a volunteer basis. In total, 20 H pylori isolates were collected, and antimicrobial susceptibility testing (on amoxicillin, tetracycline, metronidazole, ciprofloxacin, levofloxacin and clarithromycin) was conducted using disk diffusion and E-test methods. Subsequently, genomic DNA from these isolates was sequenced to detect mutations associated with antimicrobial resistance. Sixty-five percent of the isolates were found to be resistant to at least one of the listed antibiotics according to E-test. Three isolates were found to be resistant to ≥3 of the above-mentioned antibiotics. Notably, 25% of the isolates were found to be resistant to both metronidazole and clarithromycin, two antibiotics that are normally prescribed as part of first-line regimens in the treatment of H pylori infections in Canada and most of the world. Among the resistant strains, the sequences of 23S ribosomal RNA and gyrA, which are linked to clarithromycin and ciprofloxacin/levofloxacin resistance, respectively, revealed the presence of known point mutations associated with antimicrobial resistance. In general, resistance to metronidazole, ciprofloxacin/levofloxacin and clarithromycin has increased since the studies in the early 2000s. These results suggest that surveillance programs of H pylori antibiotic resistance may need to be revisited or improved to prevent antimicrobial therapy failure.