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The present study was conducted to determine the antimicrobial resistance pattern and biofilm-formation ability in 100 Avian-Pathogenic Escherichia coli (APEC) isolated from colibacillosis-suspected broilers and 100 Avian Fecal E. coli (AFEC) isolates from healthy broilers in Hamedan, Iran. All isolates were screened by polymerase chain reaction for antimicrobial resistance genes, class 1 and 2 integrons, and biofilm-associated genes. Besides, we assessed the possible relationship between biofilm-formation ability antibiotic resistance patterns, genetic background, and the pathogenicity of APEC strains. 81% of APEC and 73% of AFEC isolates showed multidrug resistance (MDR) phenotype; in addition, 45% of the APEC and 21% of the AFEC strains showed biofilm-formation ability. This is the first report of the biofilm formation ability in E. coli isolated from broilers in Iran. The most prevalent antibiotic resistance gene in APEC strains was tetA (68%), followed by sul1 (63%), dfrA1-like (51%), and blaTEM (30%), whereas in AFEC strains, the frequencies of the antibiotic resistance genes were tetA (63%), sul1 (58%), dfrA1-like (49%), and blaTEM (22%). Out of 81 MDR APEC isolates, 53 (65.4%) and 38 (46.91%) isolates were positive for intI1 and intI2 genes, respectively. In the AFEC strains intI1 and intI2 genes were presented in 57 and 33 isolates, respectively. All APEC isolates belonging to phylogenetic groups B1, B2, and C were MDR. The results of the present study indicate that isolates with biofilm-forming ability show more MDR properties and probably have more pathogenicity to broilers. [ABSTRACT FROM AUTHOR]

Background: Klebsiella pneumoniae is one of the leading causes of hospital outbreaks worldwide. Also, antibiotic-resistant K. pneumoniae is progressively being involved in invasive infections with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the incidence of resistance genes (integron types and β-lactamase-encoded genes) among clinical isolates of K. pneumoniae. Methods: In this cross-sectional study, a total of 100 clinical samples were obtained from hospitalized patients in three teaching hospitals in the north of Iran, from November 2018 and October 2019. Antimicrobial susceptibility testing was performed using disk agar diffusion test in line with CLSI recommendations. For colistin, minimum inhibitory concentration (MIC) was determined using broth microdilution. Based on antibiogram, multi-drug resistant (MDR) and extensive-drug resistant (XDR) strains were detected. Finally, integron types and β-lactamase resistance genes were identified using polymerase chain reaction technique. Results: The most and least clinical samples were related to the urine and bronchoalveolar lavage, respectively. Based on the antibiogram results, amikacin and gentamicin exhibited good activity against K. pneumoniae strains in vitro. The high resistance rate (93%) to ampicillin/sulbactam predicts the limited efficacy of this antibiotic, in the hospitals studied. Among all the 100 isolates, the frequency of MDR and XDR phenotypes were 58% and 13%, respectively, while no pan-drug resistant (PDR) strains were found. In the MDR K. pneumoniae strains, the prevalence of blaSHV, blaTEM, blaCTX-M-15, blaKPC, blaOXA-48, blaNDM β-lactamase genes were 91.4%, 82.7%, 79.3%, 29.3%, 36.2% and 6.9%, respectively, however 91.4% of the isolates were carrying intI gene. Class II and III integrons were not detected in any isolates. Conclusion: The MDR K. pneumoniae is becoming a serious problem in hospitals, with many strains developing resistance to most available antimicrobials. Our results indicate co-presence of a series of β-lactamase and integron types on the MDR strains recovered from hospitalized patients. The increasing rate of these isolates emphasizes the importance of choosing an appropriate antimicrobial regimen based on antibiotic susceptibility pattern. [ABSTRACT FROM AUTHOR]

Background: Acinetobacter baumannii is an opportunistic pathogen that can cause several kinds of nosocomial infections. Increasing antibiotic resistance as well as identifying genetic diversity and factors associated with pathogenicity and prevalence of this bacterium is important. The aim of this study was the investigation of molecular typing, biofilm production, and detection of carbapenemase genes in multidrug-resistant Acinetobacter baumannii isolated from different infection sites using ERIC-PCR in Iran. Methods: Forty isolates of A. baumannii were obtained from various wards of the central hospital, in the west of Iran. Phenotypic identification and genetic diversity, biofilm production assay, and detection of Carbapenemase genes carried out. Results: Tracheal samples 26 (61.9 %) are the most frequent isolates, and 95 % of isolates were identified as MDR. 32.5 % of all A. baumannii strains were capable to form a strong biofilm. It was founded that antimicrobial resistance patterns had a significant relationship with strong biofilm formation (P = 0.001). Most frequencies of the studied genes were in the order of VIM (81 %), SPM (45.2 %), and IMP (35.7 %) genes. The VIM gene was the most frequent in all isolates which were significant (P = 0.006). 14 different ERIC-types were observed including 7 common types and 7 unique or single types. F type is the largest common type consisting of nine isolates and B, D, and E types contain two isolates separately. Conclusions: ERIC-PCR technique was used to genetically classify A. baumannii isolates as one of the most common microorganisms in nosocomial infections. [ABSTRACT FROM AUTHOR]

Some isolates of bacteria were taken from various places inside the hospital, including operating theaters, corridors, ventilation areas, floors, and other samples were taken from patients suffering from antibiotic resistance. The study aims to discover the multiple resistant bacteria present in the hospital environment, to discover the extent of their resistance, and to detect the gene NDM-1, NDM-2, which when they are present, the bacteria are highly resistant. When a patient is infected with multiple resistant bacteria, he sufers from all antibiotic resistance and may lead to death, which is the biggest problem in the world today. [ABSTRACT FROM AUTHOR]

Background: Klebsiella pneumoniae is a common cause of nosocomial infections. Antibiotic resistance and ability to form biofilm, as two key virulence factors of K. pneumoniae, are involved in the persistence of infections. The purpose of this study was to investigate the correlation between antimicrobial resistance and biofilm formation capability among K. pneumoniae strains isolated from hospitalized patients in Iran. Methods: Over a 10-month period, a total of 100 non-duplicate K. pneumoniae strains were collected. Antibiotic susceptibility was determined by Kirby–Bauer disk diffusion method according to CLSI. Biofilm production was assessed by tissue culture plate method. Finally, polymerase chain reaction was conducted to detect four families of carbapenemase: blaIMP, blaVIM, blaNDM, blaOXA−48; biofilm formation associated genes: treC, wza, luxS; and K. pneumoniae confirming gene: rpoB. Results: Most of the isolates were resistant to trimethoprim-sulfamethoxazole (52 %), cefotaxime (51 %), cefepime (43 %), and ceftriaxone (43 %). Among all the 100 isolates, 67 were multidrug-resistant (MDR), and 11 were extensively drug-resistant (XDR). The prevalence of the blaVIM, blaIMP, blaNDM, and blaOXA−48 genes were 7 , 11 , 5 , and 28 %, respectively. The results of biofilm formation in the tissue culture plate assay indicated that 75 (75 %) strains could produce biofilm and only 25 (25 %) isolates were not able to form biofilm. Among these isolates, 25 % formed fully established biofilms, 19 % were categorized as moderately biofilm-producing, 31 % formed weak biofilms, and 25 % were non-biofilm-producers. The antimicrobial resistance among biofilm former strains was found to be significantly higher than that of non-biofilm former strains (p < 0.05). Molecular distribution of biofilm formation genes revealed that 98 , 96 , and 34 % of the isolates carried luxS, treC, and wza genes, respectively. Conclusions: The rise of antibiotic resistance among biofilm-producer strains demonstrates a serious concern about limited treatment options in the hospital settings. All of the data suggest that fundamental actions and introduction of novel strategies for controlling of K. pneumoniae biofilm-related infections is essential. [ABSTRACT FROM AUTHOR]

Objective: The present study aimed to investigate the frequency and antibiotic susceptibility pattern of Gram-negative bacteria (GNB) isolated from surgical site infections (SSIs) in the North of Iran. Results: This cross-sectional study conducted over a two-year period during 2018-2020 on all cases of SSIs who had a positive culture for a GNB. Standard microbiological tests were followed for the bacterial isolation and identification. Antimicrobial susceptibility profiles were determined using disk diffusion method. During the study period, a total of 78 nonduplicated GNB isolated from SSIs. The most prevalent surgical procedures were fracture fixation (37.2%), and tissue debridement (23.1%). Klebsiella isolates showed the highest isolation rate (29.5%) followed by Enterobacter (28.2%), and Acinetobacter (16.7%). Antibiotic susceptibility results showed that Acinetobacter isolates were almost resistant to all of the tested antibiotics, except gentamicin, co-trimoxazole, and meropenem. Enterobacteriaceae isolates showed the lowest resistance against amikacin, co-trimoxazole, and imipenem. Overall, 49 (62.8%) of isolates were multiple drug-resistant (MDR). In summary, a remarkable rate of MDR isolates which showed an increasing trend during recent years is a serious alarm for the management of SSIs caused by GNB. Moreover, the results of regional assessments, provide good epidemiological background for comparing our situation with other regions. [ABSTRACT FROM AUTHOR]

Purpose: The integrons, as the mobile exogenous elements, play a prominent role in the spreading of antimicrobial resistance genes from Pseudomonas aeruginosa clinical isolates to other bacteria. This study aimed to investigate the frequency of class 1 integrons andresistance gene cassettes carrying by them in clinical isolates as well as multidrug resistant P. aeruginosa. Materials and Methods: A total of 100 clinical isolates of P. aeruginosa were collected from 5 hospitals in Mazandaran province, north Iran. The antibiotic susceptibility pattern of the isolates was evaluated using the disk agar diffusion method. Genomic DNAs were extracted and then the presence of class 1 integrons was detected by the PCR test. All PCR products of the positive isolates were sequenced for the detection of resistance gene cassettes by the Sanger method. Results: Forty-one percent of the clinical isolates were multi-drug resistant. Also, 42% of the isolates were contained class 1 integron, and 61.9% of the integron positive isolates were detected as MDR. We detected 10 different gene cassettes sizing from 0.6 to 3.5 kb in the present study. The sequencing analysis of the internal variable regions of the class 1 integrons showed that the 0.75 kb gene cassette (aadB) was the most frequent resistance gene (54.76%) among all clinical isolates, as well as the MDR isolates. Other resistance genes detected in this study were included: aadA6-orfD (35.71%), aacA4-blaOXA-10 (21.42%), aadB-aacA4-blaOXA-10 (19.04%), blaOXA-10-aacA4-VIM 1 (11.9%), aacA4-catB10 (7.14%), aacA5-aadA1-cmlA5 (7.14%), blaOXA31-aadA2 (4.76%), and aac(3)-Ic-aacA5-cmlA5 (4.76%). To the best of our knowledge, blaOXA-10-aacA4-VIM1 cassette array is detected for the first time in this study. Conclusion: The treatment of infections caused by P. aeruginosa in this region of Iran is a major problem due to the high prevalence of class 1 integrons. It seems that the high prescription of beta-lactams and aminoglycosides for the treatment of these infections may be replaced by other combination therapy stewardships. [ABSTRACT FROM AUTHOR]

Purpose: Given the importance of treatment failure due to multidrug-resistant (MDR) strains, studies on population structure of these organisms are necessary to improve control strategies. Accordingly, the current study aimed to determine the prevalence of carbapenem-resistant P. aeruginosa (CRPA) at a teaching referral hospital in Iran and to analyze their molecular clonality by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) for epidemiological purposes. Methods: In this study, modified Hodge test (MHT) and double-disk synergy test (DDST) were used for carbapenemase production and metallo-β-lactamases (MBLs) screening, respectively. All P. aeruginosa isolates were tested for antimicrobial resistance. Moreover, MBL genes (blaIMP, blaVIM, blaSPM, blaNDM) were detected by multiplex PCR assay. Results: Among 68 P. aeruginosa clinical isolates, 38 (55.88%) isolates were CRPA. Antibiotic susceptibility testing revealed that most of these isolates were MDR. PFGE analyses showed 5 common types and 27 single types among CRPA isolates. MLST analysis revealed three major clusters (MLST-sequence types (STs): 235, 357, and 861) among them. The 30 non-CRPA isolates corresponded mainly to MLST-STs 253, 360, and 446. Conclusion: Our results showed that internationally distributed MLST-STs with widely genomic diversity have spread in our hospital, and clonal expansion of MDR strains of P. aeruginosa was described as well. [ABSTRACT FROM AUTHOR]

Background: Diarrheagenic Escherichia coli (DEC) is a significant cause of gastroenteritis and a major public health problem. This study investigates the prevalence and the antibiotic resistance patterns of DEC that were isolated from infectious diarrhea samples of pediatric patients from central Iran. Patients and Methods: Pediatric diarrhea samples were collected from 230 pediatric patients visiting the hospital. E. coli pathotypes were diagnosed by using conventional culture methods and PCR. Antibiotic resistance profiles, the frequency of multi-drug resistance (MDR), and the phenotypic and genotypic characteristics of extended spectrum-β-lactamase (ESBL), AmpC and integron-associated genes were analyzed. Results: Of the 230 samples of infectious diarrhea, 91 (39.5%) produced E. coli isolates. Of these, 32 cases (35.1%) were identified as DEC by culture and PCR. The frequency of the E. coli pathotypes obtained was as follows: EAEC 11/32 (34.3%), EPEC 9/32 (28.1%), ETEC 6/32 (18.7%), EIEC 3/32 (9.3%), and EHEC 3/32 (9.3%). The antibiotic resistance rates were greater for nalidixic acid (30/32; 93.7%), ampicillin (29/32; 90.6%), and tetracycline (25/32; 78.1%) than for any of the other tested antibiotics. High levels of MDR (25/32; 78.1%) and the presence of ESBL (18/32; 56.2%) and AmpC (9/32; 28.1%) were observed in the DEC isolates. The isolates showed a higher frequency of the ESBL genes [blaTEM (18/18; 100%), blaCTX-M15 (17/18; 94.4%)], and AmpC [blaCIT (4/9; 44.4%) and blaDHA (4/9; 44.4%)] than of the other ESBL and AmpC genes. Conclusion: Compared to the previous study, DEC appeared to be the second-most abundant agent of diarrhea in pediatric patients after Campylobacter jejuni, with frequent MDR and ESBL presence. [ABSTRACT FROM AUTHOR]

Objective(s): Plasmid-mediated quinolone resistance (PMQR) determinants and integrons have a considerable contribution to bacterial drug resistance in gram-negative pathogens. We studied the prevalence of PMQR genes and integron carriage in multidrug-resistant community isolates of Klebsiella spp. Materials and Methods: Two hundred and fifty Klebsiella spp. isolates were collected from outpatient specimens between August 2015 and October 2017 in Yazd central Laboratory, Iran. Antibiotic susceptibility was determined against 17 antibiotics and minimum inhibitory concentration (MIC) of ciprofloxacin was measured by E-test. Polymerase chain reaction (PCR) was employed for detection of qnrA, qnrB, qnrS, aac(6’)-Ib-cr, oqxAB and qepA genes. Results: Disc diffusion results showed that 17 isolates (6.8%) were multidrug resistant (MDR), two of which were Klebsiella oxytoca and 15 were Klebsiella pneumoniae. MIC measurements revealed 11 ciprofloxacin-resistant isolates (including the two K. oxytoca), three intermediately-resistant and three ciprofloxacin-susceptible isolates. All ciprofloxacin-resistant and intermediately-resistant isolates carried at least one and up to four PMQR genes. The most prevalent PMQR gene was oqxAB (93.75%) followed by aac(6’)-ib-cr (50.0%), qnrB (25.0%) and qnrS (18.75%) but qnrA and qepA were not detected. Class 1 integron was observed in 14 (82.3%) isolates including nine ciprofloxacin-resistant, two intermediately-resistant, and three susceptible isolates. Class 2 and 3 integrons were not observed. Conclusion: Presence of MDR, multiple PMQR determinants as well as class 1 integron in community isolates of Klebsiella spp. can be an important source of transmission of these opportunistic pathogens. [ABSTRACT FROM AUTHOR]

Purpose: Proteus mirabilis is one of the most important agents of urinary tract infection (UTI). As there are limited data abou the pathogenicity P. mirabilis isolated from Iran, we investigated the virulence characteristics and antibiotic resistance in the isolates. Finally, the genotypic patterns were evaluated by Pulse field gel electrophoresis (PFGE). Methods: A total of 110 isolates of P. mirabilis causing UTIs were isolated from patients in Tehran, Iran. The virulence characteristics and antimicrobial susceptibility were assayed using phenotypic methods. Extended-spectrum β-lactamases (ESBLs) production was assayed by the combination disk diffusion test (CDDT). Presence of virulence genes and antimicrobial-resistant genes was detected by Polymerase chain reaction (PCR). Finally, thirty-three isolates were selected for PFGE. Results: All isolates showed the ability of biofilm and hemolysin formation. Antibiotic resistance ranged from 59.1% about cotrimoxazole to 2.7% about amoxicillin-clavulanic acid. Sixteen (14.5%) of the isolates were classified as multi-drug resistant (MDR). All isolates amplified mrpH, mrpA, pmfA, ureG and hpmA genes. Furthermore, the prevalence of zapA, fliC, ptaA, and ucaA genes was 98.2%, 98.2%, 95.5%, and 95.5%, respectively. The prevalence of plasmid-mediated quinolone resistance (PMQR) genes was 4.5% and 0.9% for aac(6ʹ)-Ib-cr and qnrA, respectively. Twenty-eight pulsotypes were detected among the 33 isolates by PFGE that pulsotypes 1, 2 and 4 with two isolates and pulsotype 3 with three isolates were the most prevalent ones. Conclusion: It was found that the P. mirabilis isolates had high frequency of virulence factors. In addition, antibiotic resistance to some antibiotics and also production of ESBLs is alarming and shows the need for hygienic procedures to prevent the dissemination of antibiotic resistance. Although PFGE showed genetic diversity among the isolates, finding of several pulsotypes among the isolates should be considered an alarm to prevent these infections in hospital environments. [ABSTRACT FROM AUTHOR]

Patients with diabetes mellitus frequently experience urinary tract infections (UTIs). In the present study, we looked at how glycemic control affects diabetic patients' rates of UTI, the causing pathogens, the presence of multi-drug-resistant (MDR) and extensively drug-resistant organisms, and the infections' relation to diabetes. Diabetes patients' midstream urine samples were included, after collecting and identifying the organisms, disc diffusion antibiotic sensitivity tests were conducted. The HbA1c was measured for all patients. A total of 500 diabetic patients provided urine samples for this study, and 189 (37.2%) of them had UTIs. Compared to 59 patients with managed glycemia, 130 individuals in the uncontrolled glycemic group experienced the most UTI cases. In both diabetic groups, females had a significantly higher prevalence of UTI than males (88.4% and 11.6%, respectively). The most common bacterial isolate, E. coli , displayed 58.4% MDR. Regardless of age or gender, glycemic control in diabetes patients is essential for decreasing UTI rates., Competing Interests: The authors declare no conflict of interest

Background: Shigella spp. are primary pathogens of diarrhea in children worldwide. Emergence of resistance to fluoroquinolones and third-generation cephalosporins is crucial in the management of pediatric shigellosis. We determined the prevalence and the antibiotic resistance patterns of Shigella species isolated from pediatric patients in central Iran. Materials and methods: Pediatric diarrhea samples (n=230) were cultured on MacConkey and XLD agar media and in GN broth. Genus-specific PCR for ipaH was also used for detection directly from fecal specimens. Antibiotic resistance and the frequency of ESBL and AmpC genes were determined. Results: Out of the 230 samples, 19 (8.2%) cases of Shigella spp. were identified using culture. Twenty-six samples were positive by PCR (11.3%), S. flexneri (4/19; 21%) and S. sonnei (15/19; 78.9%) being the most detected. The highest antibiotic resistance rates were found for cotrimoxazole (19/19; 100%), ampicillin (16/19; 84.2%), cefixime (13/19; 68.4%) and ceftriaxone (12/19; 63.1%). Ten cases showed phenotypic ESBL presence and all these strains were positive for blaTEM, blaCTX-M-1, and blaCTX-M-15. Three strains were AmpC positive, all of which harbored blaCMY-2 and two contained blaCIT. Of the 19 Shigella isolates 5 (26.3%), 2 (10.5%), and 1 (5.2%) were phenotypically resistant to nalidixic acid, ciprofloxacin, and norfloxacin, respectively. Class 1 integron was found in 18 (94.7%) isolates whereas class 2 integron was found in 19 (100%) strains. Conclusion: We found a considerable presence of Shigella species with elevated antibiotic resistance levels. In particular, the resistance to third-generation cephalosporins (ESBL) and ciprofloxacin must be taken seriously. [ABSTRACT FROM AUTHOR]

Objective(s): Integrons, as a potential element in the distribution and maintenance of drug resistance, have thoroughly been established. It is known that the high prevalence of integrons in multidrugresistant (MDR) clinical isolates has become a serious public health concern. The objective of the present study was to determine the frequency of different classes of integrons in clinical isolates in Iran. Materials and Methods: Electronic global databases were systematically searched. The raw data for integrons among bacterial isolates were collected and their prevalence was analyzed using Comprehensive Meta-Analysis V2.0 (Biostat, Englewood, NJ, USA) software. Results: In a comprehensive literature review, 29 eligible studies were determined with their metaanalyses indicating the prevalence of integron class 1 to be 41% (95% CI 36.3-46.1) and integron class 2 as 17.7% (95% CI 13-23.3) in Gram-negative bacteria. The highest prevalence of integron class 1 was reported in Acinetobacter spp (58%) while the highest prevalence of integron class 2 was reported in Shigella isolates (83.7%). The frequencies of class 1 integron in MDR (79%) and non-MDR isolates (41%) were higher than those for class 2 integron in MDR (13.4%) and non-MDR isolates (17.7%). Conclusion: The current systematic review demonstrated the significant presence of integrons among clinical isolates. Our analysis showed that measures such as estimates of the prevalence of this transposable element and diligence in continued surveillance might be necessary to prevent its spread. [ABSTRACT FROM AUTHOR]

Background: Multi-drug resistant (MDR) ventilator associated pneumonia (VAP) may lead to inappropriate empiric antimicrobial treatment and poor outcomes. The purpose of this study was to investigate MDR pathogens' effect on the VAP patients in order to improve the treatment choice and outcome. Methods: We retrospectively studied a collection of 132 VAP patients that confirmed the characteristics, risk factors and outcomes of pneumonia. MDR VAP patients were also compared with non-MDR VAP patients. Results: MDR and non-MDR pathogens were found in 96 (72.7%) and 36 (27.3%) of the patients, respectively. The most common organism was Klebsiella pneumoniae and the most fatal MDR pathogen was Staphylococcus aureus. The MDR VAP was found to be associated with an increased length of stay in intensive care unit (ICU), increased hospital stay, and longer intubation time. No statistically significant association was found between prior antimicrobial use and MDR-VAP The mortality rate of MDR VAPs was significantly higher than non-MDR VAPs. Conclusion: Discharging patients from ICU and hospital and extubation of the patients as early as possible are two important interventions for prevention of MDR-VAP Regarding prior antimicrobial use, no significant difference was observed between MDR and non-MDR VAPs. Administration of empiric antibiotic therapy seems to have a protective effect, decreasing mortality without evidence of contributing to multi-drug resistance. [ABSTRACT FROM AUTHOR]

This study was conducted to find the etiology of acute diarrhea in Iranian children and determine the antimicrobial resistance patterns. The pathogenic bacteria were recovered from 110/269 (40.9%) diarrheal fecal samples with the following profiles: the most predominant pathogen was diarrheagenic Escherichia coli (DEC) (43.6%), comprising enteroaggregative E. coli (23.6%), enteropathogenic E. coli (10.9%), enteroinvasive E. coli (5.5%), and enterotoxigenic E. coli (3.6%); Shigella spp. (37.3%), Salmonella spp. (12.7%) and Campylobacter jejuni (6.4%) were ranked second and fourth in terms of prevalence, respectively. The rates of extended-spectrum beta-lactamase (ESBL) production were 66.7% and 53.7% in DEC and Shigella, respectively. Resistance to ampicillin (AMP) (95.1%), trimethoprim/sulfamethoxazole (SXT) (73.2%), azithromycin (ATH) (21.9%), and ciprofloxacin (CIP) (14.6%) was observed among Shigella isolates. Multidrug resistance phenotype was observed in 24.4% (10/41) of Shigella isolates, with the most common pattern of resistance to cefotaxime, ceftriaxone, ceftazidime, AMP, SXT, and ATH. This study indicates an alarming increase in the ESBL production of DEC and Shigella spp. and identifies them as the two most prevalent diarrhea-causing enteropathogens in the region. The results show that CIP could be an alternative to third-generation cephalosporins against these two pathogens. Therefore, it is proposed that further investigation be done in the pursuit of alternative antibiotics that are effective against the resistant cases. For instance, one study could look into the comparative clinical effectiveness of third-generation cephalosporins versus CIP, the latter not being presently the drug of choice for the treatment of acute diarrhea in children in Iran. [ABSTRACT FROM AUTHOR]

Background: Antibiotic resistance rates in E. coli are rapidly rising, especially with regard to fluoroquinolones. One of the mechanisms that lead to antibiotic resistance is efflux pumps. The aim of this study was phonotypic and genotypic analysis of efflux pump role in fluoroquinolones resistance of E. coli strains isolated from hospitalized patients in Kermanshah 2013. Materials and Methods: In this cross-sectional study, 100 isolates of E. coli were collected from hospitalized patients from Kermanshah. All isolates were identified by standard biochemical tests. The antimicrobial susceptibility patterns were determined by disk diffusion method according to CLSI guidelines. The presence of Efflux pump genes was determined by a PCR method. Results: The rates of resistance to Ceftazidime, Nalidixic Acid, Ciprofloxacin, Norfloxacin, Ofloxacin, Gentamicin, and Tetracycline were 73%, 67%, 55%, 54%, 45%, 38%, and 24%, respectively. According to the results of PCR test, of 100 E. coli isolates, 99% of isolates were positive for acrA, 98% for acrB, 95% for acrE, 98% for acrF, 94% for mdfA, 96% for norE, and 96% for tolC. Conclusion: In Strains with positive gene acrA, acrB, acrA, acrB, tolC, mdfA, norE, the presence of efflux pump inhibitor reduced the amount of resistance to antibiotics. So, efflux pumps are important in antibiotic resistance. [ABSTRACT FROM AUTHOR]

Acinetobacter species particularly Acinetobacter baumannii (A . baumannii ) have been widely reported as broad-spectrum antibiotic resistant pathogens. Expression of various types of metallo beta-lactamases (MBL), classified as Ambler class B, has been associated with carbapenem resistance. Here, we attempted to assess the frequency of extensively drug-resistant (XDR) and MBL-producing A . baumannii among clinical isolates. 86 clinical A . baumannii strains were collected from 2014 to 2015 and their susceptibility to meropenem (10 μg), imipenem (10 μg), azteronem (30 μg), pipracillin (100 μg) tazobactam (110 μg), tobramycin (10 μg), fosfomycin (200 μg), rifampicin (5 μg), colistin (10 μg), tigecycline (15 μg), sulbactam/ampicillin (10 μg + 10 μg) and polymixin B (300 U) was evaluated using disk diffusion method. The MBL-producing isolates were screened using combined disc diffusion method. Furthermore, the presence of bla VIM , bla IMP , bla SPM , bla GIM , bla SIM and bla NDM was detected by PCR. 34.9% of isolates were recovered from bronchoalveolar lavage (BAL). 81 (94.2%) and 62 (71.2%) isolates were multidrug resistance (MDR) and XDR, respectively. 44 (51.2%) and 65 (75.6%) isolates were MBL-producing strains with resistance to imipenem and meropenem, respectively. 2 (2.3%), 13 (15.1%), 2 (2.3%), 4 (4.7%) and 2 (2.3%) isolates carried bla VIM , bla IMP , bla SPM , bla GIM and bla SIM genes, respectively. Our data showed that the rate of XDR and MBL A . baumannii is on the rise. [ABSTRACT FROM AUTHOR]

Cholera remains to be an international threat, with high rates of illness and death. In 2012 and 2013, two cholera outbreak happened in Iran, affecting lots of people. Vibrio cholerae O1 was confirmed as the etiological agent. Source identification and controlling the spread of the cholera disease are two critical approaches in cholera outbreaks. In this study, thirty V. cholerae O1 isolates were selected and has been evaluated for antimicrobial resistant as well as molecular typing by multilocus variable-number tandem-repeat analysis (MLVA) method. Twenty-nine (97%) isolates were sero-grouped as El Tor (one isolate was classical) and 100% were related to Inaba serotype. All of the isolates were susceptible to ciprofloxacin, chloramphenicol, ampicillin and gentamicin. On the other hand, 60% of the isolates were MDR (resistant to 3 or more classes). There were three resistance patterns. The most prevalent pattern was resistance to streptomycin, erythromycin, trimethoprim-sulfamethoxazole, and tetracycline ( ST-SXT-E-T ) which was seen in 50% of isolates. Using MLVA method 14 MLVA types were identified. MLVA type 2 (5-7-7-16-15) accounted for 43% of isolates. Isolates with the same genotype often did not have the same antibiogram. Overall, the data indicate that the Iranian V. cholerae were MDR and clonaly related. Furthermore, the results of this study shows that MLVA can be used as useful method for V. cholerae genotyping in epidemiological investigations. [ABSTRACT FROM AUTHOR]

Resistance to oxyimino cephalosporins antibiotics in Enterobacteriaceae is primarily done by the extended spectrum β-lactamases (ESBLs). Clear identification of risk factors for ESBLs-producing infections is necessary. Therefore, efficient strategies can be developed to decrease outbreak of these infections. The aim of this study was to determine the antibacterial susceptibility and ESBLs pattern of diarrhogenic Escherichia coli (E. coli) strains isolated from adult patients. In the present study, diarrheogenic E. coli strains were isolated from 54 patients from the University of Medical Sciences hospitals in Shiraz. Antimicrobial susceptibility testing was done by disk diffusion method by CLSI criteria. The presence of blaTEM, blaSHV and blaCTX-M genes was investigated by PCR using designated primers. The prevalence of ESBLsproducer E. coli strains was 12.96%. Antimicrobial resistance testing showed a high resistance to cefexime, trimethoprim-sulfamethoxazole, ampicillin and penicillin. Overall, β-lactamase genes were identified in 52 (96.30%) isolates which were identified as 45 (83.33%) blaTEM, 17 (31.48%) blaSHV and 11 (20.37%) blaCTX-M. ESBLs-producer E. coli is very prevalent in diarrheogenic strains isolated from adult patients. Also, this study clearly showed that the blaTEM gene for ESBLs-producer E. coli was widespread in Iran. [ABSTRACT FROM AUTHOR]

Background and Objective: Mycobacterium tuberculosis has developed resistance to antituberculosis drugs and becoming a major and alarming public health problem in worldwide. This study was aimed to determine antituberculosis drug resistance rate and to identify multidrug resistant tuberculosis (MDR-TB) in West of Iran. Materials and Methods: Of 130 samples were included between December 2011 and July 2012 in the study from that 112 cases were M. tuberculosis. The proportional method was carried out according to the Clinical and Laboratory Standards Institute on Lowenstein-Jensen against isoniazid, rifampicin, streptomycin, ethambutol, pyrazinamide, para aminosalicylic acid, ethionamide, cycloserine (CYC). The microdilution method was carried out using 7H9 broth with 96 well-plates. Results: From 112 isolates, resistance was observed to isoniazid 18 (16.07%), rifampicin 16 (14.28%), streptomycin 25 (22.32%), ethambutol 15 (13.39%), pyrazinamide 27 (24.10%), para aminosalicylic acid 19 (16.96%), CYC 4 (3.57%), and ethionamide 14 (12.5%) cases. 16 isolates were MDR. Conclusion: The high prevalence of MDR-TB in our study is assumed to be due to recent transmission of drug-resistant strains. Overall, the rate of drug resistance in our study was high, which is in line with findings of some high-burden countries. Hence that early case detection, rapid drug susceptibility testing, and effective anti-TB treatment is necessary. [ABSTRACT FROM AUTHOR]

Background: Streptococcus pneumoniae causes serious infections worldwide. The aim of this study was to determine the molecular characteristic, antibiotic resistance pattern and capsular types of invasive S. pneumoniae in Tehran, Iran., Results: Of the 44 pneumococcal invasive isolates, 39 (89%) were isolated from children and 5 (11%) from adults. The results show that all pneumococcal isolates were susceptible to linezolid but had varying resistance to trimethoprim-sulfamethoxazole (86%), erythromycin (73%), tetracycline (66%), clindamycin (43%), penicillin (16%), chloramphenicol (14%) and levofloxacin (2%). The range of erythromycin, tetracycline and penicillin MICs were 2 - ≥ 256 μg/mL, 4 - ≥ 48 μg/mL, and 0.047 - ≥ 256 respectively. All of the penicillin resistant isolates were multidrug resistant (MDR) and in addition to penicillin were resistant to tetracycline, erythromycin and trimethoprim-sulfamethoxazole. The most common capsular types detected in 64% of the pneumococcal isolates was 6A/B, 19A, 15A, 23F. The multilocus sequence typing (MLST) of 10 pneumococcal isolates revealed 9 different sequence types (STs), including ST 15139 (capsular type 19A) and ST 15140 (capsular type 23F), which have not previously been reported., Conclusions: The study revealed that the S. pneumoniae isolates belonged to diverse capsular types and clones with high rate of resistance to erythromycin, tetracycline, and penicillin.

Background: Multi-drug resistant (MDR) Acinetobacter baumannii is one of the most important causes of nosocomial infections. The purpose of this study was to identify antibiotic resistance patterns, biofilm formation and the clonal relationship of clinical and environmental isolates of A. baumannii by Pulsed Field Gel Electrophoresis method. Forty-three clinical and 26 environmental isolates of the MDR A. baumannii were collected and recognized via API 20NE. Antibiotic resistance of the isolates was assessed by the disk diffusion method, and the biofilm formation test was done by the microtiter plate method. Pulsed Field Gel Electrophoresis (PFGE) was used to assess the genomic features of the bacterial isolates., Results: The resistance rate of clinical and environmental isolates against antibiotics were from 95 to 100%. The difference in antibiotic resistance rates between clinical and environmental isolates was not statistically significant (p > 0.05). Biofilm production capabilities revealed that 31 (44.9%), and 30 (43.5%) isolates had strong and moderate biofilm producer activity, respectively. PFGE typing exhibited eight different clusters (A, B, C, D, E, F, G, and H) with two significant clusters included A and G with 21 (30.4%) and 16 (23.2%) members respectively, which comprises up to 53.6% of all isolates. There was no relationship between biofilm formation and antibiotic resistance patterns with PFGE pulsotypes., Conclusions: The results show that there is a close relationship between environmental and clinical isolates of A. baumannii. Cross-contamination is also very important that occurs through daily clinical activities between environmental and clinical isolates. Therefore, in order to reduce the clonal contamination of MDR A. baumannii environmental and clinical isolates, it is necessary to use strict infection control strategies.

Here, we aimed to determine the susceptibility of 70 Mycobacterium tuberculosis isolates obtained from different regions of the country to 8 anti-tuberculosis (anti-TB) drugs and possible underlying mechanisms causing resistance to rifampin, isoniazid, and pyrazinamide. The susceptibility of 70 isolates of M. tuberculosis to anti-TB drugs was tested using proportion method. Strains showing resistance to the first line anti-TB drugs were subjected to PCR amplification and sequencing of the rpoB, katG, ahpC, pncA genes, inhA promoter and oxyR-ahpC intergenic regions to detect resistance conferring mutations. Overall, 77.1% and 77.1% of isolates were resistant to at least one of the tested first- and second-line drugs, respectively. Within the rpoB gene the highest rate of mutation was found in codons 531(450) (56.3%), and 533(452) (12.5%). Also, codons 315 (42.4%) of katG, positions -48, -72 and -77 of oxyR-ahpC (total= 3, 9.1%) and -15 of inhA promoter region (33.3%) were the most altered positions in isoniazid resistant isolates. Only a single mutation was detected for pncA among resistant isolates. High prevalence of resistance to essential anti-TB drugs among M. tuberculosis strains isolated from retreated tuberculosis cases is alarming issue necessitating immediate action to prevent the spread of drug resistant isolates in the country.

Introduction: Over the past decades, prevalence of biofilm-forming Staphylococcus aureus strains has significantly increased in urinary tract infections. The aim of this study was to investigate prevalence of biofilm forming and adhesion encoding genes and to analyze distribution of different agr and spa types in S. aureus isolates., Methodology: In the present study, 75 S. aureus isolates obtained from patients with urinary tract infections were examined for susceptibility to antimicrobial agents. Adhesion, biofilm, and spa encoding genes were detected by PCR screening; agr types were determined using multiplex PCR., Results: Among the 75 isolates, 72% were biofilm producers and 28% were non-biofilm producers. Notably, the ability to produce biofilm was higher among MRSA strains ompared to MSSA strains. The most prevalent biofilm forming gene was icaD (77.3%), followed by icaA (76%), icaB (57.3%) and icaC (50.7%). Adhesion genes clfA, clfB, fnbB, can, fnbA, ebp and bap were detected in 94.7%, 92%, 68%, 64%, 64%, 60% and 5.3% of the isolates, respectively. The spa types t426 and t7789 were found among the non-MDR isolates. It was found that t790, t084, t7789 and t325 spa types were biofilm producers, while t426 and t1339 spa types were non-biofilm producers., Conclusion: Biofilm encoding genes icaD and spa type t790 and agr type III were the most prevalent factors among MDR biofilm producer isolates. The study emphasized that identification of genes and characterization of molecular types involved in biofilm formation should be considered., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2019 Mehdi Goudarzi, Anis Mohammadi, Anahita Amirpour, Maryam Fazeli, Mohammad Javad Nasiri, Ali Hashemi, Hossein Goudarzi.)

The emergence of extended-spectrum beta-lactamases (ESBL) producing strains become a great concern, because few antimicrobial agents remain active against them. Due to the lack of data on the genotyping characteristics and antibiotics resistance of clinical isolates of Klebsiella pneumoniae in the north of Iran, this study aimed to determine the occurrence of ESBL-producing isolates and their molecular characteristics in order to analyses their epidemiological relationships. This cross-sectional study performed on 60 K. pneumoniae isolates which were recovered from different clinical specimens within May and November 2016. Isolates were identified by standard microbiologic tests and confirmed by API 20E strip. Antimicrobial susceptibility testing was carried out by disk diffusion method. The genetic relatedness among the isolates was assessed by RAPD-PCR. Totally, the lowest level of susceptibility was toward amoxicillin/clavulanat, and nalidixic acid. On the other hand, the highest level of susceptibility was toward imipenem (86.7%). The rate of ESBL-producing isolates was 45% (27/60). There was a significant association between production of ESBLs and higher antibiotic resistance in tested isolates. The RAPD-PCR dendrogram revealed 5 major clusters with a similarity of 80% which indicates the high relatedness of the studied isolates. Twenty-one isolates out of the 27 ESBL-producing isolates were clustered in cluster A. In summary, results showed the high prevalence of multiple-drug resistant and ESBL-producing K. pneumoniae isolates in our ICUs. Also, results revealed a significant similarity between ESBL-producing isolates that necessitate restricted infection control policies and rational prescription and use of antibiotics.

Background: Production of Beta-Lactamase enzymes, especially extended- spectrum Beta -Lactamases (ESBL), is a primary mechanism of resistance in these bacteria.The purpose of this study was detection of blaTEM, blaSHV, blaCTXM, blaCTX-M-15, blaPERand blaVEBin K. pneumoniae, isolated from clinical specimens by the PCR method and antibiotic susceptibility patterns in these strains isolated., Materials and Methods: During a period from October 2015 to July 2016, 52 K. pneumoniae isolates were collected from general hospitals in the city of Sanandaj, Iran. After identifying the strains by biochemical testing, the disc diffusion method was used for determining antimicrobial susceptibility and screening the ESBL-producing isolates. Detection of blaTEM, blaSHV, blaCTX-M, blaCTX-M-15, blaPER and blaVEBESBL-producing K. pneumoniae was carried out by PCR., Results: Out of 52-collected K. pneumoniae, highest and lowest rates of resistance related to co-trimoxazole with 67.3 % and amikacin with 30.7 %. 55.7% identified as MDR and 69.23% were ESBL-producing K. pneumoniae.blaSHV was the most prevalent gene in ESBL-producing K. pneumoniae. blaTEM,blaCTX-M,blaCTX-M-15 producing K. pneumoniae strains showed higher rates of drug resistant compared with negative strains (P < 0.05)., Conclusion: Results of this study showed that the prevalence rate of ESBL-producing K. pneumoniae isolates is increasing in MDR strains, which raises concerns regarding the treatment of K. pneumoniae. Therefore, molecular research in the field of antimicrobial resistance of bacteria is essential to prevent the spread of resistant strains., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Nosocomial infection caused by carbapenem-resistant Acinetobacter baumannii (CRAB) has created a public health concern all around the world. In this study, 100 isolates of CRAB from hospitalized patients during 2015-2016 at Imam Khomeini Hospital were investigated to determine the rates of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains using Kirby-Bauer disk diffusion method. The minimum inhibitory concentrations (MICs) of six antibiotics were determined by broth microdilution method. Multiplex polymerase chain reaction (PCR) was performed to detect bla OXA-51 like and bla OXA-58 like , bla OXA-23 like , and bla OXA-24 like that are encoding resistance to carbapenems. All CRAB isolates were MDR and XDR and 2% of them were pandrug-resistant (PDR), whereas colistin, polymyxin B, and tigecycline were the most effective agents. All isolates were positive for bla OXA-51 like by PCR. The frequency of bla OXA-23 like and bla OXA-24 like was 81% and 22%, respectively. Findings of this study showed that very few therapeutic options remained for the treatment of CRAB infections and bla OXA-23 like is a dominant resistance gene in CRAB at this hospital.

Acinetobacter baumannii potential to form biofilm and exhibit multiple antibiotic resistances may be responsible in its survival in hospital environment. Accordingly, our study was aimed to determine the correlation between ability of biofilm formation and the frequency of biofilm related genes with antibiotic resistance phenotypes, and also the categorization of their patterns in clinical and environmental isolates. A total of 75 clinical and 32 environmental strains of the A. baumannii were collected and identified via API 20NE. Antibiotic susceptibility was evaluated by disk diffusion and microdilution broth methods. Biofilm formation assay was performed by microtiter plate method. OXA types and biofilm related genes including Bla OXA-51 , Bla OXA-23 , Bla OXA-24 , Bla OXA-58 , bap, bla PER-1 , and ompA were amplified by PCR. The rate of MDR A. baumannii in clinical isolates (100%) was higher than environmental (81.2%) isolates (p < 0.05). Among 10 antibiotypes, the predominant resistance pattern in clinical and environmental isolates was antibiotypes I (85.3 and 78.1%, respectively). Analysis of the frequency of bla OXA-23 gene revealed a statistically significant difference between clinical (85.3%) and environmental (68.7%) isolates (p < 0.05). The prevalence of strong biofilm producers in clinical and environmental isolates were 31.2%-58.7%, respectively. In the clinical and environmental isolates, the frequencies of ompA, bla RER-1 and bap genes were 100%, 53.3%, 82.7% and 100%, 37.5%, 84.4% respectively. Statistical analysis revealed a significant correlation between the frequency of MDR isolates and biofilm formation ability (p = 0.008). The high frequency of antibiotype I would be indicated that an outbreak has been happened earlier and an endemic strain is currently being settled in the hospital environment. It would be suggested that if there was no difference in the frequency of pattern I and biofilm formation ability between clinical and environmental isolates, it is a critical point representing the higher risk of bacterial transmission from environment to the patients. The resulting data would be assisted in the improvement of disinfection strategies to better control of nosocomial infections. One dominant resistance pattern has shown among clinical and environmental isolates. The frequency of blaOXA-23 had significant difference between clinical and environmental isolates. The presence of bap gene in the A. baumannii isolates was associated with biofilm formation. There was a significant correlation between multiple drug resistance and biofilm formation. The clinical isolates had a higher ability to form strong biofilms compared to the environmental samples., (Copyright © 2017 Elsevier Ltd. All rights reserved.)