There are documents that confirm the cycle of bacterial transmission between patients, staff, and the inanimate environment. The environment may have more effect on intensive care units (ICUs), because the patients who require intensive care have unstable clinical conditions and are more sensitive to infections. The aim of this study was to determine the prevalence of bacteria in air and inanimate surface in the ICUs and to compare the microbial levels to standard levels.Air and inanimate surface in the four ICUs of a teaching hospital underwent weekly surveillance by means of air sampler and swabs for a period of six-month. Total bacterial counts were evaluated onto trypticase soy agar and mannitol salt agar (MSA).A total of 725 samples [air (168) and inanimate surfaces (557)] were collected. The total mean ± SD CFU/m3 of airborne bacteria in all of the ICUs were 115.93 ± 48.04. The most common bacteria in air of the ICUs were Gram-positive cocci (84.2%). The total mean ± SD airborne of Staphylococcus aureus was 12.10±8.11 CFU/m3. The highest levels of S. aureus contamination were found in ventilators and bed ledges. More suitable disinfection of hospital environments and monthly rotation in utilization of the various disinfectant agents are needed for the prevention of airborne and inanimate transmission of S. aureus.

Infections due to Staphylococcus aureus have become increasingly common among burn patients. The antibiotic resistance profile of S. aureus isolates and inducible resistance against clindamycin were investigated in this study. The presence of mecA gene, mupA gene and macrolide resistance genes were detected using PCR and multiplex-PCR. The resistance rate to methicillin, erythromycin and mupirocin were 58.5%, 58% and 40%, respectively. The prevalence of constitutive and inducible resistance among macrolide resistant isolates was 75% and 25%, respectively. Ninety five percent of the isolates were positive for one or more erm genes. The most common genes were ermA (75%), ermC (72%) and ermB (69%), respectively. The ermA gene predominated in the strains with the inducible phenotype, while ermC was more common in the isolates with the constitutive phenotype. The msrA gene was only found in one MRSA isolate with the constitutive phenotype. A total of 27 isolates (25%) carried the mupA gene. All the mupirocin resistant isolates and almost all the erythromycin resistant isolates were also resistant against methicillin which may indicate an outbreak of MRSA isolates with high-level mupirocin and erythromycin resistance in the burn unit assessed.

The synergy between gentamicin and vancomycin, teicoplanin, ampicillin and linezolid was studied by time-kill method. Two clinical vancomycin resistant enterococci (VRE) and two vancomycin susceptible enterococci (VSE) isolates were used. Different concentrations of antibiotics were combined. Two VSE strains and the control strain exhibited synergism with the combination of gentamicin, vancomycin, teicoplanin, ampicillin and linezolid. Two VRE strains exhibited synergism with the combination of gentamicin and ampicillin. Synergy between gentamicin and vancomycin, teicoplanin and linezolid was not observed against these isolates. The VRE isolates were positive for vanA, aac (6')-Ie aph (2") and aph (3')-IIIa genes and their vancomycin, teicoplanin and gentamicin MICs were 512 μg/ml, 512 μg/ml and >4000 μg/ml, respectively. In order to treat serious enterococcal infections, further clinical evaluation is needed to examine the in vitro combined effects of gentamicin and vancomycin, teicoplanin and linezolid.

OBJECTIVE: Adenoids have been associated with the pathogenesis of acute, recurrent and chronic infectious diseases of the upper respiratory system and their hypertrophy is one of the most common causes of upper airway obstruction affecting children. In this study, the characteristics of Staphylococcus aureus isolates from patients who had undergone adenoidectomy were investigated via spa typing method. METHODS: A total of 113 children with adenoid hypertrophy who underwent adenoidectomy during September 2009 to November 2010, were included in the study. The isolates were identified to the species level as S. aureus using standard biochemical methods, following which the amplification and sequencing of the spa gene X region were carried out. RESULTS: S. aureus was found in the adenoid tissue of 26 (23%) patients. Out of the 26 S. aureus isolates, 5 (19%), 3 (11.5%) and 3 (11.5%) were resistant to tetracycline, erythromycin and oxacillin respectively. All the isolates were susceptible to vancomycin, rifampin, ciprofloxacin, gentamicin, mupirocin and quinupristin-dalfopristin and were typed using spa typing method. All the isolates were found to include 21 spa types, including two previously unreported types (t7685 and t7692). The most prevalent spa types were t7685 (11.5%), t230 (8%), t325 (8%) and t1149 (8%). CONCLUSION: This study demonstrates that the prevalence rate of S. aureus in the adenoid tissue of the children assessed was 23%. An interesting point to note was the dominance of the spa type t7685 that has not been previously reported by other studies.

Background: Fluoroquinolones are broad-spectrum antibiotics widely used in the treatment of bacterial infections such as Staphylococcus aureus isolates. Resistance to these antibiotics is increasing.<br /> Material/Methods: The occurrence of mutations in the grlA and gyrA loci were evaluated in 69 fluoroquinolone-resistant S. aureus isolates from 2 teaching hospitals of Tehran University of Medical Sciences.<br /> Results: Out of the 165 S. aureus isolates, 87 (52.7%) were resistant to methicillin and 69 (41.8%) were resistant to fluoroquinolone. Fluoroquinolone-resistant S. aureus isolates had a mutation at codon 80 in the grlA gene and different mutational combinations in the gyrA gene. These mutational combinations included 45 isolates at codons 84 and 86, 23 isolates at codons 84, 86 and 106 and 1 isolate at codons 84, 86 and 90. Fluoroquinolone-resistant S. aureus isolates were clustered into 33 PFGE types.<br /> Conclusions: The findings of this study show that the fluoroquinolone-resistant S. aureus strains isolated in the teaching hospitals in Tehran had multiple mutations in the QRDRs region of both grlA and gyrA genes.<br />

OBJECTIVE: To determine the presence of common bacterial agents of otitis media with effusion (OME), together with investigation these agent in the adenoid tissue and antimicrobial susceptibility pattern of isolated bacteria in Iranian children with OME. METHODS: Polymerase chain reaction (PCR) and bacterial culture methods were used for detection and isolation of Alloicoccus otitidis, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae in 63 middle ear fluid samples and 48 adenoid tissues from 48 OME patients. Fifteen patients were bilaterally affected. Antimicrobial susceptibility of all bacterial isolates were determined by disk agar diffusion (DAD) method. RESULTS: Bacteria were isolated from 47%(n=30) of the middle ear fluid samples and 79%(n=38) of the adenoid tissue specimens in OME patients. A. otitidis was the most common bacterial isolated from the middle ear fluid 23.8% by culture and 36.5% by PCR method. S. pneumoniae was the most prevalent pathogen (35.5% and 31.2% by culture and PCR) in the adenoid tissues. In 10 patients the same organisms were isolated from the middle ear fluid and adenoid tissue. Antimicrobial susceptibility pattern showed taht most isolates of bacteria were sensitive to ampicillin, Amoxicillin/Clavulanate and fluoroquinolones. CONCLUSION: The present study, being the first report on the isolation of A. otitidis by culture method in Iran and Asian countries, shows that A. otitidis is the most frequently isolated bacterium in Iranian children having otitis media with effusion. In this study A. otitidis, S. pneumoniae, H. influenzae and M. catarrhalis are the major bacterial pathogens in patients with OME and we found that ampicillin and Amoxicillin/Clavulanate have the excellent activity against bacterial agents in Iranian children with OME.

Extended spectrum β-lactamase (ESBL)-producing trait was present in 48 out of the 112 (42.8%) Pseudomonas aeruginosa isolates collected from burn wound infections during a 12-month period. The presence of oxa-10, per-1, veb-1 and ges genes and the multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) of 112 P. aeruginosa strains were determined by PCR and multiplex PCR. Disk diffusion methods were used to determine the susceptibility of the isolates to antimicrobial agents as instructed by CLSI. All ESBL isolates were resistant to aztreonam, cefepime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone and ofloxacin. Fewer than 60% of ESBL isolates were resistant to imipenem, meropenem, and piperacillin-tazobactam but more than 90% were resistant to amikacin, ciprofloxacin, levofloxacin, ticarcillin and tobramycin. The most prevalent ESBL genes included oxa-10 (70%) and per-1 (50%) followed by veb-1 (31.3%). The gene encodes GES enzyme did not detect in any isolates. A total of 100 P. aeruginosa strains were typed by MLVF typing method. MLVF produced 42 different DNA banding patterns. These data indicate that different MLVF types infect burn wounds in patients at a hospital in Tehran and also suggest an alarming rate of ESBL-producing isolates in this test location.

Methicillin-resistant Staphylococcus aureus (MRSA), particularly the multidrug-resistant clones, is an increasing worldwide problem. The average incidence rate of MRSA in Tehran was found to be over 40%. A total of 140 MRSA isolates obtained from patients attending a teaching hospital in Tehran, from May 2009 to December 2009, were included in this study. The antimicrobial susceptibility profile of MRSA isolates was determined by the agar disk diffusion method. Molecular analysis of MRSA strains was accomplished by Pulsed-Field Gel Electrophoresis (PFGE) and Multi-locus sequence typing (MLST). Detection of mecA gene was used to confirm resistance to methicillin among the MRSA isolates. All the MRSA isolates were susceptible to chloramphenicol, teicoplanin, tigecycline and vancomycin. All MRSAisolates were resistant to oxacillin, whilst 139 strains showed resistance against ciprofloxacin, erythromycin, gentamicin, tetracycline and trimethoprim-sulfamethoxazole. PFGE analysis of all the 140 MRSA isolates produced five distinct pulsotypes designated as pulsotypes A-E. Most of the isolates (n=132) were clustered into pulsotype A. The most prevalent sequence type (ST) was ST 239 (pulsotype A) found in 82%(37/45) of the tested isolates. The second most prevalent type was ST 1238 (pulsotypes B, C and D) found in 15%(7/45) of the isolates. The remaining type, ST 8 (pulsotype E) was found in a single isolate. The results of this study indicated that the MRSA clone ST 239 was a major clone in the selected university hospital of Tehran and that it was widely spread among the different wards as well as all the age groups of patients.

HASH(0x6144870)

This ex vivo study compared saliva coronal microleakage in root canals filled with Resilon/Epiphany Self-Etch (SE) system after final irrigation with different solutions. A total of 60 extracted single-rooted human teeth were instrumented using Mtwo Ni-Ti rotary instruments and divided into two experimental groups (n = 20 each) and positive and negative control groups (n = 10 each). The canals were irrigated with 1.3% NaOCl during instrumentation. After removing the smear layer with 17% EDTA, the root canals in groups A and B were flushed with distilled water and 2% chlorhexidine (CHX), respectively, after which they were obturated with Resilon/Epiphany SE using lateral compaction technique. After sterilizing the whole system with gamma-rays, saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 h for 60 days. The data collected were then analyzed using the chi-square test and Kaplan-Meier survival analysis. As compared with group A, the specimens in group B tended to be more resistant to saliva leakage; however, the difference was not significant (P > 0.05). In conclusion, our findings suggest that 2% CHX is a good conditioner for root canal dentin before use of Resilon/Epiphany SE.(J Oral Sci 52, 83-87, 2010).