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Background & Objective: in recent years antibiotic resistance of Pseudomonas aeruginosa is increased as a causetive factor in hospital contamination. This study was done to determine the prevalence and antibiotics susceptibility of Pseudomonas aeruginosa isolated from inanimate objects in Taleghani hospital.

 

Materials & Methods: This descriptive study was done on inanimate objects in different wards of Taleghani hospital during 2006. Sampling was performed by sterile gauze pad for dry surfaces and swab for wet surfaces. To differentiate and identify P.aeruginosa, various culture media such as Brain Heart Infusion Agar, Citrimide Agar and Triple Sugar Iron Agar were used. Antibiotic sensitivity of the isolated strains was determined by Kirby-Bauer Method using Muller-hinton Agar medium. Moreover, antiseptic sensitivity of the strains to Decosept and Povidone-Iodine as the main antiseptic agents was identified by determining Minimal Bactericidal Concentration and Minimal Inhibitory Concentration using Nutrient Agar and Nutrient Broth media.

 

Results: Fifty-five of the total 292 samples were positive for P.aeruginosa. Based on the ratio of the number of positive samples to the total samples, Thalassemia ward (38.5%) was the most infected ward and taps (61.1%) was the most infected sampling place. None of the samples from room atmosphere and intensive care equipments were positive for P.aeruginosa. 20% of the samples were resistant to ceftazidime and 32.7% were resistant to piperacillin, also 10.9% of samples were resistance to both ceftazidime and piperacillin.

 

Conclusion: This study showed that contamination with P.aeruginosa and antibiotic resistance of the isolated bacteria are the main problems in Taleghani hospital.

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Background and Objective: Pseudomonas aeruginosa is one of the important causes of nosocomial infections. Extended spectrum-beta Lactamases (ESBLs) and Metallo-beta Lactamase (MBL) producing strains have become resistant against a wide range of antibiotics. The aim of this study was to determine the effect of Methanol extract of Camellia Sinensis on Pseudomonas aeruginosa producing ESBL isolated from burnt wounds of patients.

Materials and Methods: This descriptive study was done on burnt wounds of 245 hospitalaized patients in Shafa hospital, Kerman, Iran during 2006-07. ESBLs producing strains were detected by phenotypic confirmatory test and also E-test strips were used for MBL detection. P.aeruginosa MIC was determined for Cefotaxime, Ceftazidime, Azteronam, Imipenem, Meropenem and methanol extracts of plant Camellia Sinensis prepared by Maceration method.

Results: 120 of burnt wound infected with P.aeruginosa, out of them 41 isolates contained ESBL while lacked MBL. 60% of isolates were resistant to Cefotaxime, 66% to Ceftazidime, 42% to Azteronam, 3% to Imipenem and 5% to Meropenem. Among the extracts, green Tea had the highest antibacterial effect on standard strains and P.aeruginosa producing ESBLs in 1.25mg/ml concentration.

Conclusion: This study showed that methanolic extract of green tea has higher antibacterial effect aginst β-lactamase P.aeruginosa strains than Cefotaxime and Ceftazidime.

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Background and Objective: Gastroenteritis due to Salmonella is common in human and considered as a global dilemma of public health. This study was done to determine the Pattern of serotyping and antibiotic resistance of Salmonella in children with diarrhea in Iran. Methods: In this laboratory study, 306 stool samples were collected from children with diarrhea in public health centers in Robat-karim, Tehran province, Iran. The specimens were enriched in Selenite F medium and then cultured on Hekton agar. The identification of Salmonella was carried out by conventional method and antimicrobial susceptibility testing was performed according to CLSI procedures. Results: Out of 306 stool samples, 7.2 % were identified as Salmonella species, as follow: 7 Salmonella typhi, 6 Salmonella paratyphi B, 3 Salmonella paratyphi C, 2 Salmonella paratyphi A and 4 samples were not identifiable. There was a significant relation between presence of WBC in fecal and salmonellosis (P<0.05). In drug sensitivity trends, 92.3% of Salmonella species were sensitive to chloramphenicol, ceftizoxime, Nalidixic acid and Amikacin. Conclusion: This study showed that Salmonella was the cause of children diarrhea in 7.2% in this region.

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Background and Objective: Resistance of Staphylococcus aureus to antibiotics is one of the major global health problems in human societies. Thus, evaluation of pattern of antibiotic resistance in its different strains is very important. This study was carried out to evaluate the antibiotic resistance in Staphylococcus aureus isolated from clinical samples by disk diffusion and PCR methods.

Methods: In this laboratory- descriptive study, 50 isolates of Staphylococcus aureus to be identified from clinical specimens. Methicillin resistance was examined using PCR and antibiotic susceptibility of isolates was tested by disk diffusion method.

Results: 50 isolates were resistant to methicillin, ampicillin and penicillin. The resistance of isolates to erythromycin, Gentamicin, Clindamycin and Ciprofloxacin were 48%, 34%, 34%, 34%, respectively. The PCR method showed that 98% of Methicillin Resistance of Staphylococcus aureus isolates carried the methicillin resistant gene.

Conclusion: This study indicated that 98% isolates harbor mecA genes and more resistant to methicillin related mecA genes.

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Background and Objective: Water resident bacteria are potentially important reservoir of antibiotic resistance genes. This study was performed to evaluate the antibiotic resistance in Escherichia coli strains isolated from raw waters of Golestan province, northern Iran.

Methods: In this descriptive study, 26 samples from Ziarat river water (13 samples pre & 13 samples post treatment) and 36 samples from Azadshahr area springs water (18 samples pre & 18 samples post treatment) were collected. 75 numbers of Escherichia coli bacterium samples (50 isolated from river and 25 isolated from springs) identified and isolated from raw waters of Golestan province, northern Iran by MPN method via differential tests. Susceptibility of Escherichia coli strains to 11 antibiotics (Amoxicillin / Clavulanic acid, Ampicillin, Imipenem, Cefalotin, Cefotaxime, Gentamicin, Amikacin, Tetracycline, Nalidixic acid, Ciprofloxacin and Trimethoprim / Sulfamethoxazole) was assayed by disk diffusion Kirby & Bauer’s method.

Results: 14 spring's raw water samples and 12 river raw water samples contained Escherichia coli. All of the river and springs samples assayed free from Escherichia coli post treatment. All of the Escherichia coli strains isolated from samples showed the similar phenotypical resistance against to surveyed 11 antibiotics. The most significance resistance to Ampicillin (river 94% & springs 88%), Amoxicillin / Clavulanic acid (river 76% & springs 80%), Tetracycline (river 14% & springs 16%) and Cefalotin (river 8% & springs 16%) viewed. Resistance to Trimethoprim / Sulfamethoxazole (8%), Nalidixic acid (2%) and Ciprofloxacin (2%) just viewed in river samples. All of the river and spring isolates were sensitive to Imipenem, Cefotaxime, Gentamicin and Amikacin and demonstrated intermediate resistance to others antibiotics.

Conclusion: Treatment of raw water from springs and rivers caused the eradication of Escherichia coli. As regard to observed phenotypical resistance in springs’ raw waters, presumably with lack of treatment springs’ raw water can be caused the transmission of antibiotic resistance to human body.

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Background and Objective: Enterococci is gram positive bacteria which is the inhabitants of gastrointestinal tract. Hospital infections and antibiotic resistance to enterococci is increased. This study was done to determine the molecular evaluation of vanA and vanB genes of enterococci isolates resistant to Vancomycin and Teicoplanin.

Methods: In this descriptive study, 113 isolates samples were collected and identified according to biochemical test and cultural characteristics in Ali ibn Abi Talib hospital in Zahedan, Iran. Antibiogram test was done to determine antibiotic resistance pattern. E-test strip was used to evaluate the minimum inhibitory of concentration (MIC). PCR was used to detect the vanA and vanB genotype in Vancomycin and Teicoplanin resistance enterococci.

Results: 92%, 6.2% and 1.8% of isolated samles collocted from urine, blood culture and pleura fluid, respectively. According to phenotype, 18.6% and 17.69% were resistance to Vancomycin and Teicoplanin, respectively. Resistance was observed in strains of Enterococcus faecalis and Enterococcus faecium. VanA genotype was seen in all of the resistance isolated species.

Conclusion: This study showed that strains of Enterococcus faecalis and Enterococcus faecium have more antibiotic resistance to the Vancomycin and Teicoplanin, morever vanA genotype precence in all of resistance isolated samples.

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Background and Objective: Pseudomonas aeruginosa is an opportunistic pathogen with numerous virulence factors such as phospholipase and type IV pili. The emergence of multidrug resistant Pseudomonas aeruginosa has become a serious public health threat worldwide. This study was done to determine the frequency of plcH, plcN, pilA and pilB genes in multi-drug resistant Pseudomonas aeruginosa isolated from clinical samples.

Methods: In this cross-sectional study, 93 isolates of Pseudomonas aeruginosa collected from different clinical samples from hospitals of Zanjan, Iran during 2013-14. After identification of isolates by biochemical tests, antibiotic susceptibility testing (Kirby-Bauer) was performed according to CLSI guidelines. Total DNA extracted and PCR was done to detect of plcH, plcN, pilA and pilB genes.

Results: Among 93 of Pseudomonas aeruginosa isolates, the highest antibiotic resistance related to Erythromycin and Cefoxitin (95.6%) and the lowest resistance related to Amikacin (26.8%). 80.6% of isolates were multidrug resistant (MDR). Out of 75 MDR isolates, the frequency of plcH, plcN, pilA and pilB genes was 97.4%, 49.3%, 26.6% and 17.3%, respectively.

Conclusion: According to high frequency of phospholipase C gene (plcH) in MDR Pseudomonas aeruginosa isolates which isolated from different clinical samples, presumably this virulence factor plays an important role in pathogenesis of this bacterium.

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Background and Objective: Listeria monocytogenes is an important food-borne intracellular pathogen which can transmit to human through contaminated foods and causing meningitis, meningoencephalitis and abortion. This study was done to determine the frequency, antimicrobial susceptibility and serotyping of Listeria monocytogenes isolated from food samples in Tehran, Iran.
Methods: This descriptive was carried on 150 food samples including vegetables, cheese and meat were collected from supermarkets, open-air markets, and delicatessens in different regions of Tehran, Iran since April to September 2018. The presumptive isolates were characterized biochemically. All L. monocytogenes isolates were further analyzed by serotyping and antimicrobial susceptibility tests.
Results: Out of 150 samples, Listeria spp. was detected in 30 (20%) samples in which 9 (6%) were positive for L. monocytogenes [vegetables (n=4, 44.44%), cheese (n=2, 22.22%) and meat (n=3, 33.33%)]. of the 9 L. monocytogenes isolates, 5 (55.55 %), 3 (33.33 %), and 1 (11.11%) belonged to serotypes 4b, 1/2b, and 1/2a, respectively. The most L. monocytogenes isolates were resistant to Trimetoprime, Sulfamethoxazole, Tetracycline, Streptomycin, Chloramphenicol, and Ciprofloxacin while were sensitive to Penicillin G, Gentamicin, Streptomycin, and Ampicillin, and were intermediately resistant to Ciprofloxacin.
Conclusion: The rate of Contamination of vegetable, cheese and meat samples with L. monocytogenes is important in Tehran, Iran. Due to the potential contamination samples to Listeria, there is necessity need for continuous monitoring and the development of a precise program for identifying this bacterium in Tehran and the whole country.

 

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Background and Objective: Salmonellosis is a gastroentritidis which caused by the different serovars of Salmonella genus, and responsible for morbidity and mortality worldwide. Food born disease is one of the growing problems of human societies especially in developing countries. The aim of this study was to evaluate and serogroup determination of Salmonella isolates from food along with antibiotic resistance pattern.
Methods: This descriptive study was performed on total of 400 in equal of 200 packed and 200 unpacked  samples of (red meat, chicken meat, egg, vegetable) collected in random from distributed in Tehran ,Iran during nine months in 2018. Microbial, biochemical and serological test was performed according to protocol number of 1800 of national standard. Antimicrobial susceptibility test was done by disk diffusion (MAST, Co, UK) method.
Results: Out of 400 samples 8 (2%) was identified as Salmonella. The unpacked foods were more contaminated (75%) compared to packed foods (25%). The most isolated serogrouping were belonging to especially D. Salmonella. The chicken samples were more contaminated (37.5%) than other samples. The isolated Salmonella were mostly resistance to nalidixic acid (75%).
Conclusion: The Salmonella isolated particularly from group 1 showed higher antimicrobial resistance, additional care should be taken in preparation, packaging and supplying the food samples.