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Breast feeding has critical effects on the newborns and either mother’s health. Some of such health-improving effects of the mother’s milk is associated with the beneficial microbes, lactic acid bacteria (LAB), which are normally present in the mother’s milk. Thus, human milk-associated lactobacilli were isolated in this study and some of their probiotic properties was investigated. Afterwards, Lactobacillus strains were screened for low pH and bile acids tolerance. Molecular identification was carried out using 16SrDNA and polymerase chain reaction (PCR). Antibiotic resistance was evaluated with disk diffusion assay and the inhibitory effect of isolates on pathogenic bacteria was examined with well assay and zone inhibition. Isolation experiments resulted in 122 human milk- associated lactobacilli belonging to 12 species. The most dominant species was Lactobacillus casei followed by Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus gasser, respectively. Screening for probiotic properties showed that 19 isolates, belonging to, Lactobacillus, have interesting probiotic characteristics. The most prevalent antibiotic resistance was observed in case of vancomycin (63.15%) and no drug resistance was detected for chloramphenicol, penicillin, rifampin (0%). Three Lactobacillus strains, designated as L4, L14 and L16, were found as potential probiotic strains since they have indicated promising inhibitory effects against the studied pathogenic bacterial strains. Our results shed light on the considerable diversity of lactobacilli in human breast milk. Furthermore, the candidate probiotic strains detected in this research might be used as potential probiotic strains. Key words: Breast milk, Lactobacillus, probiotics, inhibitory effect, polymerase chain reaction.

Background: Quinolone resistant Salmonella serotypes have been reported in recent years and have become increasingly widespread worldwide. Objectives: We evaluated the molecular mechanism of quinolone resistance in non-typhoidal Salmonella strains isolated from clinical samples in Tehran, Iran. Methods: The present study included the Salmonella isolates originated from hospitalized individuals and outpatients in Tehran, Iran. Serotyping of nalidixic acid-resistant Salmonella isolates was done by slide agglutination method. Then, the quinolone resistance-determining region (QRDR) of topoisomerase gene gyrA and the plasmid-mediated quinolone resistance (PMQR) determinants were detected using the polymerase chain reaction (PCR) method. Restriction fragment length polymorphism (RFLP) analysis was also employed to determine the possible mutation in the gyrA gene of those strains. Mutant strains were detected by enzymatic digestion, and their PCR products were sequenced immediately. Results: Amongst 141 isolates, 60% showed nalidixic acid resistance, whereas none of them were ciprofloxacin-resistant. The commonly prevalent serotypes were S. Enteritidis and S. Infantis. Of 85 nalidixic acid-resistant strains, 17 (20%) isolates harbored the qnrS gene. However, PCR analysis of the quinolone-resistant strains did not detect qnrA and qnrB genes. PCR-RFLP and sequencing analysis of the QRDRs of the gyrA gene indicated that 16 (18.8%) isolates had mutant patterns, and the most common point mutation was serine to phenylalanine at position 83. Conclusions: Our results demonstrated that point mutations in gyrA and the existence of plasmid-mediated gene qnrS were important mechanisms of quinolone resistance in non-typhoidal Salmonella strains isolated from human origin. Other alternative mechanisms of resistance, such as alterations in the expression of efflux pumps, should be studied to provide greater insight into the molecular mechanism of quinolone-resistant non-typhoidal Salmonella isolates.

Many fungal diseases remain poorly addressed by public health authorities, despite posing a substantial threat to humans, animals, and plants. More worryingly, few classes of anti-fungals have been developed to combat fungal infections thus far. These medications also have certain drawbacks in terms of toxicity, spectrum of activity, and pharmacokinetic properties. Hence, there is a dire need for discovery of novel anti-fungal agents. Melittin, the main constituent in the venom of European honeybee Apis mellifera, has attracted considerable attention among researchers owing to its potential therapeutic applications. To our knowledge, there has been no review pertinent to anti-fungal properties of melittin, prompting us to synopsize the results of experimental investigations with a special emphasis upon underlying mechanisms. In this respect, melittin inhibits a broad spectrum of fungal genera including Aspergillus, Botrytis, Candida, Colletotrichum, Fusarium, Malassezia, Neurospora, Penicillium, Saccharomyces, Trichoderma, Trichophyton, and Trichosporon. Melittin hinders fungal growth by several mechanisms such as membrane permeabilization, apoptosis induction by reactive oxygen species-mediated mitochondria/caspase-dependent pathway, inhibition of (1,3)-β-d-glucan synthase, and alterations in fungal gene expression. Overall, melittin will definitely open up new avenues for various biomedical applications, from medicine to agriculture. • Venom-derived peptides have potential for development of anti-microbial agents. • Many fungal pathogens are susceptible to melittin at micromolar concentrations. • Melittin possesses multi-target mechanism of action against fungal cells.

Protozoan diseases such as malaria, leishmaniasis, Chagas disease, and sleeping sickness still levy a heavy toll on human lives. Deplorably, only few classes of anti-protozoan drugs have thus far been developed. The problem is further compounded by their intrinsic toxicity, emergence of drug resistance, and the lack of licensed vaccines. Thus, there is a genuine exigency to develop novel anti-protozoan medications. Over the past years, melittin, the major constituent in the venom of European honeybee Apis mellifera, has gathered the attention of researchers due to its potential therapeutic applications. Insofar as we are aware, there has been no review pertinent to anti-protozoan properties of melittin. The present review outlines the current knowledge about anti-protozoan effects of melittin and its underlying mechanisms. The peptide has proven to be efficacious in killing different protozoan parasites such as Leishmania, Plasmodium, Toxoplasma, and Trypanosoma in vitro. Apart from direct membrane-disruptive activity, melittin is capable of destabilizing calcium homeostasis, reducing mitochondrial membrane potential, disorganizing kinetoplast DNA, instigating apoptotic cell death, and induction of autophagy in protozoan pathogens. Emerging evidence suggests that melittin is a promising candidate for future vaccine adjuvants. Transmission-blocking activity of melittin against vector-borne pathogens underscores its potential utility for both transgenic and paratransgenic manipulations. Nevertheless, future research should focus upon investigating anti-microbial activities of melittin, alone or in combination with the current anti-protozoan medications, against a far broader spectrum of protozoan parasites as well as pre-clinical testing of the peptide in animal models.

Over the past years, short anti-microbial peptides have drawn growing attention in the research and trade literature because they are usually capable of killing a broad spectrum of pathogens by employing unique mechanisms of action. This study aimed to evaluate the anti-bacterial effects of a previously designed peptide named PVP towards the clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) in vitro. Secondary structure, cytotoxicity, and membrane-permeabilizing effects of the peptide were also assessed. PVP had a tendency to adopt alpha-helical conformation based upon structural predictions and circular dichroism spectroscopy (in 50% trifluoroethanol). The peptide showed MIC values ranging from 1 to 16 µg/mL against 10 strains of MRSA. In contrast to ciprofloxacin and gentamicin, PVP at sub-lethal concentration (1 µg/mL) did not provoke the development of peptide resistance after 14 serial passages. Remarkably, 1 h of exposure to 4 × MBC of PVP (8 µg/mL) was sufficient for total bacterial clearance, whereas 4 × MBC of vancomycin (8 µg/mL) failed to totally eradicate bacterial cells, even after 8 h. PVP showed negligible cytotoxicity against human dermal fibroblasts at concentrations required to kill the MRSA strains. The results of flow cytometric analysis and fluorescence microscopy revealed that PVP caused bacterial membrane permeabilization, eventually culminating in cell death. Owing to the potent anti-bacterial activity, fast bactericidal kinetics, and negligible cytotoxicity, PVP has the potential to be used as a candidate antibiotic for the topical treatment of MRSA infections.

Background: Pathogenicity O island 122 (OI-122) associated with the severity of Enteropathogenic Escherichia coli (EPEC) disease. Objectives: The aim of this study was the characterization of OI-122 in Iranian EPEC isolates. Methods: The distribution patterns of OI-122 were investigated in 42 EPEC strains by detection of OI-122 genes and serogrouping, multi locus VNTR (MLVA) typing, and phylogenetic grouping. Results: The complete OI-122 was identified in 18.75% of tEPEC and in 3.8% of aEPEC strains, an incomplete OI-122 with various combinations of genes was found in 75% of tEPEC and 30.76% of strains aEPEC, and OI-122 genes were absent in 6.25% of tEPEC and 65.3% of aEPEC strains. nleB (52.4%) was the most frequently detected, and the prevalence of pagC, efa1/lifA, and sen genes were 19%, 16.7%, and 14.3%, respectively. The most common phylogenetic group among tEPEC and aEPEC strains were B1 (68.75% and 80.76%, respectively). The common serogroups among EPEC isolates were O128, O111, O55, O127, and O44, and 45.2% of the isolates were untypeable. Forty-one MLVA types among 42 EPEC strains were classified into 7 clonal complexes. Conclusions: The diverse distribution of OI-122 genes among MLVA clonal groups provides evidence for dynamic evolution regarding the OI-122 pathogenicity island in tEPEC and aEPEC strains. The results also indicate that the acquisition of OI-122 gene contents occurs in a modular manner.

Bacterial biofilms are multicellular aggregates enclosed in a self-created biopolymer matrix. Biofilm-producing bacteria have become a great public health problem worldwide because biofilms enable these microorganisms to evade several clearance mechanisms produced by host and synthetic sources. Over the past years, different flavonoids including quercetin have engrossed considerable interest among researchers owing to their potential anti-biofilm properties. To our knowledge, there is no review regarding effects of quercetin towards bacterial biofilms, prompting us to summarize experimental evidence on its anti-biofilm properties. Quercetin inhibits biofilm development by a diverse array of bacterial pathogens such as Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Pseudomonas aeruginosa. Prevention of bacterial adhesion, suppression of quorum-sensing pathways, disruption or alteration of plasma membrane, inhibition of efflux pumps, and blocking nucleic acid synthesis have been documented as major anti-biofilm mechanisms of quercetin. Overall, anti-biofilm activity of quercetin can open up new horizons in a wide range of biomedical areas, from food industry to medicine.

Salmonella is an important cause of food-borne infection worldwide. Detection of outbreaks caused by Salmonella spp. relies on suitable and robust methods for genotyping. Little is known about the genetic diversity of the Salmonella enterica subspecies enterica serotype Infantis strains isolated from human sources in Iran. In this study, 40 isolates of S. Infantis, which were previously recovered from patients with gastroenteritis or diarrhea in Tehran between years 2007 and 2009, were subjected to multiple-locus variable-number of tandem repeat (VNTR) analysis (MLVA), pulsed-field gel electrophoresis (PFGE), and ERIC-PCR. Using MLVA method, 31 types were identified. The MLVA clustering of the isolates by the unweighted pair group method with arithmetic mean (UPGMA) revealed the presence of two major clusters. The discriminatory power of MLVA was superior to that of PFGE and ERIC-PCR. Overall, our data showed that MLVA assay could effectively differentiate closely related strains. It is technically simple and inexpensive to perform. Furthermore, MLVA can be used as a helpful method for epidemiological investigations.

Klebsiella pneumoniae is one of the most important agents of community-acquired urinary tract infection (CA-UTI). In addition to extended-spectrum β-lactamases (ESBLs), a number of virulence factors have been shown to play an important role in the pathogenesis of K. pneumoniae, including capsule, siderophores, and adhesins. Little is known about the genetic diversity and virulence content of the CTX-M-15-producing K. pneumoniae isolated from CA-UTI in Iran. A total of 152 K. pneumoniae isolates were collected from CA-UTI patients in Tehran from September 2015 through April 2016. Out of 152 isolates, 40 (26.3%) carried blaCTX-M-15. PCR was performed for detection of virulence genes in CTX-M-15-producing isolates. Furthermore, all of these isolates were subjected to multiple-locus variable-number of tandem repeat (VNTR) analysis (MLVA). Using MLVA method, 36 types were identified. CTX-M-15-producing K. pneumoniae isolates were grouped into 5 clonal complexes (CCs). Of these isolates, mrkD was the most prevalent virulence gene (95%), followed by kpn (60%), rmpA (37.5%), irp (35%), and magA (2.5%). No correlation between MLVA types or CCs and virulence genes or antibiotic resistance patterns was observed. Overall, it is thought that CTX-M-15-producing K. pneumoniae strains isolated from CA-UTI have arisen from different clones.

Antimicrobial peptides are considered to be excellent templates for designing novel antibiotics because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance. In this study, for the first time, a series of short hybrid antimicrobial peptides combined by different fragments of venom-derived alpha-helical antimicrobial peptides pEM-2, mastoparan-VT1, and mastoparan-B were designed with the intent to improve the therapeutic index of the parental peptides. Short hybrid antimicrobial peptides PV, derived from pEM-2 and mastoparan-VT1, was found to possess the highest antibacterial, hemolytic, and cytotoxic activity. Short hybrid antimicrobial peptides PV3, derived from pEM-2 and three fragments of mastoparan-VT1, showed more than threefold improvement in therapeutic index compared with parental peptides pEM-2 and mastoparan-VT1. PV had the highest antimicrobial activity in stability studies. Except BVP, designed based on all three parental peptides, the other short hybrid antimicrobial peptides at their minimal inhibitory concentration and 2× minimal inhibitory concentration required less than 120 and 60 min to reduce >3log10 the initial inoculum, respectively. All peptides had membrane-disrupting activity in a time-dependent manner. Collectively, this study highlights the potential for rational design of improved short hybrid antimicrobial peptides such as PV3 that was an ideal candidate for further assessment with the ultimate purpose of development of effective antimicrobial agents.

Antimicrobial peptides are attractive candidates for developing novel therapeutic agents, since they are lethal to a broad spectrum of pathogens and have a unique low tendency for resistance development. In this study, mechanism of action and in vitro anti-pseudomonal activity of previously designed short hybrid antimicrobial peptide PV3 were investigated. Compared to ceftazidime, PV3 had not only higher antibacterial activity but also faster bactericidal activity. PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. Although the antimicrobial activity of PV3 was reduced in Mueller-Hinton broth (MHB) containing human serum, it was still active enough to eradication of bacteria at low concentrations. Compared with standard condition (MHB only), there was no significant decrease in antibacterial activity of PV3 against P. aeruginosa strains under 150 mM NaCl (p = 0.615) and 1 mM MgCl2 (p = 0.3466). Fluorescence microscopy and field emission scanning electron microscopy further indicated that PV3 killed bacteria by disrupting the cell membrane. Since PV3 has potent anti-pseudomonal activity and has little cytotoxicity in vitro, it seems plausible that the peptide should be further investigated with animal studies to support future pharmacological formulations and potential topical applications.

Microbial water-borne diseases still affect developing countries and are major water quality concerns throughout the world. Routine culture-based methods of identifying bacterial pathogens in water sources are laborious and time-consuming. Recently, the use of molecular techniques such as the polymerase chain reaction (PCR) has provided rapid and highly promising detection methods. In this study, we developed two multiplex PCR assays for simultaneous detection of six water-borne bacteria. Two triplex PCR protocols were developed to detect six target genes. The first protocol targets uidA (Escherichia coli), int (Shigella spp.), and gyrB (Pseudomonas aeruginosa) genes, while invA (Salmonella spp.), ompW (Vibrio cholera), and lacZ (coliforms) were amplified by the second protocol. Specificity testing was carried out for 12 reference strains. Furthermore, the applicability of the multiplex PCR assays for detection of these bacteria was investigated for 52 surface water samples. The results indicated that all primer pairs showed specificities only for their corresponding target organisms. The detection sensitivity of both multiplex PCR assays was 3 × 102 − 3 × 103 colony forming units. The developed assays represent simple and efficient diagnostic procedures for co-detection of water-borne bacteria and have the potential to provide earlier warnings of possible public health threats and more accurate surveillance of these organisms.

During the past decade, cationic antimicrobial peptides (CAPs) have gained particular interest among researchers, since they often display broad-spectrum antimicrobial activity and low possibility of resistance emergence. This study aimed to investigate in vitro effectiveness of Mastoparan-1 (MP-1), a tetradecapeptide CAP from hornet venom, against methicillin-resistant Staphylococcus aureus (MRSA) isolates. MP-1 had a high propensity to form alpha-helix based on structural predictions. MP-1 was found to possess strong antimicrobial activities and weak cytotoxic effects. Multiple treatments of MRSA with MP-1 at sub-lethal dose did not induce resistance. At 4 × minimum bactericidal concentration (MBC), MP-1 eradicated bacteria within 60 min, whereas vancomycin was unable to eradicate MRSA even after 480 min of exposure, highlighting rapid bactericidal kinetics of MP-1. Treatment of bacteria with 2 × MBC of MP-1 caused a time-dependent increase in orange/red fluorescence intensity. Compared with vancomycin, MP-1 significantly reduced biofilm formation and diminished both biofilm biomass and viability of biofilm-embedded bacteria in a concentration-dependent manner. Taken together, the current data reveal not only that MP-1 is a potent bactericidal and antibiofilm agent, but also that it is less likely to invoke antimicrobial resistance, reinforcing further studies concerning the therapeutic applications of MP-1.

Background: Uropathogenic E. coli (UPEC) is the primary cause of human urinary tract infections (UTIs) worldwide. Moreover, there has been renewed and growing interest in using older antibiotics for treatment, such as aminoglycosides. Objectives: The goal of this study was to determine the plasmid profile patterns of UPEC isolates harboring the aminoglycoside resistance gene aac(3)-IIa. Patients and Methods: A total of 276 uropathogenic E. coli (UPEC) samples were isolated from UTI patients at the Tehran heart cente rin Tehran, Iran. Antimicrobial susceptibility testing against five aminoglycosides was performed by the disk diffusion method, and the aac(3)-IIa gene was detected via PCR. Moreover, plasmid profiling was carried out on those UPEC isolates harboring the aac(3)-IIa gene. Finally, the similarities among these isolates were determined on the basis of their plasmid profiles. Results: The highest level of resistance was seen for tobramycin (24.6%), and the aac(3)-IIa gene was found in 51 isolates. Twentyseven different plasmid profiles were identified among the isolates harboring the aac(3)-IIa gene, with the 15 kb plasmid being the most common. Moreover, no significant correlation was found between the resistance patterns and the number of plasmids. The cluster analysis based on the plasmid profiles grouped the isolates into five different clusters, of which cluster one was the largest (containing 14 of 51 isolates). Conclusions: Our data suggest the monitoring of aminoglycoside resistance, and its consideration in the empirical therapy of UPEC infections.

Background: Dysentery accounts for a significant proportion of morbidity and mortality cases, especially in children with diarrhea in developing countries. Shigellosis remains a public health problem in Iran. Objectives: The objectives of this study were to investigate the presence and the frequency of Shigella spp. among children younger than 10 years with diarrhea and to determine the antimicrobial resistance patterns of these isolates in Tehran, Iran. Patients and Methods: This cross-sectional study was conducted in two pediatric hospitals in Tehran, from October, 2013 to October, 2014. Nine hundred and thirty-eight (n = 938) stool samples were collected (one stool per patient) from children less than 10 years of age. The stools were primarily cultured on MacConkey agar and xylose lysine deoxycholate (XLD). (Selenite-F broth is also used as an enrichment medium for the isolation of Shigella spp.) All of the isolates were confirmed as Shigella species by biochemical and serological tests. Molecular confirmation of Shigella isolates was determined by polymerase chain reaction (PCR) using specific primers for the ipaH gene. The antibiotic susceptibility of the Shigella isolates was tested using the Kirby-Bauer disc-diffusion method. Results: Amongst 938 stool samples, 36 were Shigella spp. S. sonnei (61.1%, n = 22), which was the most common, followed by S. flexneri (27.8%, n = 10), S. boydii (8.3%, n = 3), and S. dysenteriae (2.8%, n = 1). Furthermore, most Shigella isolates showed resistance to amoxicillin (83.3%), tetracycline (61.1%), and co-trimoxazole (83.3%). No resistance was found against ciprofloxacin and imipenem. This study showed that S. sonnei is currently the predominant species in Tehran, Iran. Conclusions: Because resistance to antibiotics changes constantly, Shigella strains should be under surveillance in order to monitor local susceptibility and subsequently formulate policies for the use of antimicrobial drugs.

Background: Antibiotic resistance is widespread among diarrheagenic Escherichia coli in developing countries, where the overuse of antibiotics is common. Information regarding β-lactamases, especially Extended-Spectrum β-Lactamases (ESBLs) in diarrheagenic pathogens should be considered in clinical management when an optimal treatment is needed. Objectives: The main objective of this study was to investigate the prevalence of blaCTX-M, blaSHV and blaTEM β-lactamase genes among enteropathogenic E. coli (EPEC) isolates in Tehran, Iran. Materials and Methods: Stool specimens were collected from children with diarrhea during a 17-month period from 2011 to 2013. Routine biochemical tests were performed for identification of E. coli isolates. The isolates were further examined by PCR for the presence of eae, stx1, stx2 and bfp genes. EPEC isolates have been screened for different β-lactamase genes. Genotyping EPEC isolates harboring blaCTX-M15 gene was performed through Multi-Locus VNTR Analysis (MLVA). Results: Of 42 EPEC, eight isolates carried the blaCTX-M1. None of the isolates carried blaCTX-M2 and blaCTX-M9. The blaCTX-M15 variant was identified in all of blaCTX-M1-positive isolates. Furthermore, blaSHV and blaTEM genes were detected in 40.5% (n = 17) and 19% (n = 8) of all EPEC isolates, respectively. No significant association was observed between the existence of bfp gene and presence of those β-lactamase genes (P > 0.05). MLVA analysis revealed high genetic diversity among blaCTX-M15-positive isolates. Conclusions: Our study emphasized the increasing role of ESBL genes, especially blaCTX-M15 in EPEC isolates.

Patients and Methods: In total, 42 enteropathogenic E. coli strains were isolated from children with diarrhea and examined for the presence of class 1 and 2 integrons. The combined disk method was also performed to detect ESBL production. Statistical analysis was used for the comparison of the categorical data. Results: Class 1 integron was identified in 24 (57.1%) isolates, while only 2 (4.8%) isolates harbored class 2 integron. Integrons were significantly associated with resistance to certain antibiotics, including; co-trimoxazole (P = 0.016) and tetracycline (P = 0.006). Of the 42 enteropathogenic E. coli isolates, 9 (21.4%) isolates were ESBL producers. However, no significant association was observed between the existence of integrons and ESBL production (P = 0.26). Conclusions: Class 1 integrons are prevalent among enteropathogenic E. coli isolates, regardless of whether or not they produce ESBLs. This study emphasizes the alarming role of integrons in antibiotic resistance within diarrheagenic E. coli strains.

Multi-drug-resistant (MDR) diarrheagenic Escherichia coli (DEC) has rapidly spread worldwide and represents the most serious threat to the management of diarrhea in developing countries. During the period from March 2011 to January 2012, a total of 450 stool samples of diarrheal children aged 0-60 months were studied. In order to detect enterotoxigenic E. coli (ETEC) and enterohemorrhagic E. coli (EHEC) simultaneously, a mixture of four primer pairs specific for eltB, estA, vt1, and vt2 genes was used in a multiplex PCR. Antimicrobial susceptibility testing was performed as the Clinical and Laboratory Standards Institute (CLSI) guidelines. A total of 140 (31·1%) DEC were isolated from 450 stool samples. Diarrheagenic E. coli exhibited high-level resistance to aztreonam (80·7%), amoxicillin (74·4%), and tetracycline (69·3%). Also, 86·4% of E. coli isolates were resistant to at least three different classes of antimicrobial agents and considered as MDR. The frequency of ETEC and EHEC pathotypes was 46·4 and 12·1%, respectively and all of these isolates were MDR. In conclusion, MDR ETEC continues to be an important agent associated with diarrhea in children from Tabriz, Iran.

and MIC. CTX-M encoding genes were identified by PCR, and blaCTX-M -carrying isolates were genotyped by rep-PCR. Results: A total of 140(70%) non-duplicate ESBL positive E. coli were determined. Imipenem and Amikacin were effective against 100% and 85% of all tested isolates respectively. Co-resistance of ESBL positive isolates to Erythromycin, Tetracycline, Co-trimoxazole and Ciprofloxacin were found in 93%, 75%, 63% and 43% of the strains, respectively. The rate of cefotaxime and ceftazidime resistant isolates dramatically decreased from 72% to 8.5% and 39% to 4.5% respectively, in the presence of clavulanic acid. Eighty nine (44.5%) E. coli isolates carried the blaCTX-M-1 group alleles. The levels of similarity of the rep-PCR fingerprints of blaCTX-M-1 isolates ranged from 40 to 90%. Conclusions: The rapid dissemination of non clonal multi-resistant CTX-M-1 producing E. coli isolates approved the need for further studies in our medical centers.