Bacteriology and Virology

Background: The normal flora of health care workers may serve as reservoirs for causing health care-associated infections in neonatal intensive care units (NICUs).
The aim of the present study was to assess the aerobic microflora on the hands and noses of nurses and non-patient care workers (NPCWs) and their antibiotic resistance patterns.
Methods: During a three-month period, samples were obtained from 48 nurses and 16 NPCWs. After identification of bacteria, antimicrobial susceptibility against 8 antibiotics was performed according to CLSI recommendations. In addition, to detect inducible clindamycin resistance (iMLSB), double disk diffusion (D-test) was carried out.
Rresults: Among microbial isolates recovered from our participants, the commonest isolates among nurses and NPCWs were coagulase-negative staphylococci (CoNS) with prevalence of 74% and 90%, respectively. Methicillin resistant staphylococci in nurses in comparison to NPCWs were significantly higher (P < 0.0001). Moreover, more iMLSB phenotypes were found among CoNS isolated from NPCWs than nurses.
Conclusion: In regard to higher rate of resistant bacteria shown in nurses compared to NPCWs and direct contact nurses with neonates and exposure to the hospital environment, it appears that in addition to hand hygiene, other interventions such as using sterile gowns and disposable gloves by personnel are necessary.

Background: Staphylococcus aureus is a major health concern worldwide especially in cutaneous diseases. The aim of this study was to determine the in vitro antimicrobial activity of mandelic acid against Staphylococcus aureus isolates.
Methods: In this study, the susceptibility of mandelic acid against two type strains and nineteen clinical isolates of Staphylococcus aureus was assessed in vitro.
Results: Mandelic acid in different concentrations of 40, 80 and 160 mg/ml showed in vitro antibacterial activity against all tested clinical isolates of Methicillin-resistant Staphylococcus aureus (MRSA) as well as the tested type strains in disk diffusion method with inhibitory zones of 11-20 mm. The minimum inhibitory concentration and minimum bactericidal concentration (MIC/MBC) for methicillin-sensitive staphylococcus aureus (MSSA) and MRSA type strains were 20/20 and 40/40 mg/ml respectively. For the nineteen clinical MRSA isolates, MIC50 and MIC90 were 20 and 40 (mg/ml) respectively and MBC50 and MBC90 were 20 and 80 (mg/ml) respectively.
Conclusion: Our results suggest that mandelic acid has an antibacterial activity against MRSA and might be a useful addition to anti-MRSA armamentarium. Further investigations regarding the use of mandelic acid in a suitable moisturizer for atopic skin, to exert the dual effects of lubrication and MRSA eradication is recommended.

"Emergence of new strains of Escherichia coli with the ability of resistance to a wide range of antibiotics necessitates the efforts to search alternatives for better treatments to deal with these infections. Chamomile is one of the most widely used herbs in the world. In this study we investigated the potential therapeutic effects of chamomile chloroform extract on E. coli intraperitoneal (IP) infection of BALB/c mice. Female BALB/c with an average weight of 20 to 25 g, were divided into 8 groups. Lethal dose of the E. coli for mice was injected IP in test groups and treated with 5.25, 10.5 and 21 mg/mL of chamomile chloroform extract. The combined effect of the extract (50 µg/mg) with amikacin and amikacin alone were also examined. The highest number of survived mice at the dose of 10.5 mg/mL of extract and the highest death rate with 5.25 mg/mL of extract was observed. In amikacin group all infected animals were survived. Mortality rate in chamomile extract combination with amikacin is almost the same as amikacin alone. The significant lowest mortality rate was observed in the some group which had been treated with a combination of extract and amikacin. The result of this study does not recommend in-vivo using of chloroform extracts of chamomile for E.coli infection via IP administration. In vivo chloroform extracts of chamomile, it seems not to have a strong antibacterial effect on E. coli IP infection of BALB/c mice."

Residents of high background radiation areas of Ramsar have lived in these areas for many generations and received radiation doses much higher than the dose limit recommended by ICRP for radiation workers. The radioactivity of the high background radiation areas of Ramsar is reported to be due to 226Ra and its decay products, which have been brought to the surface by the waters of hot springs. Over the past years the department has focused on different aspects of the health effects of the elevated levels of natural radiation in Ramsar. This study was aimed to perform a preliminary investigation on the bioeffects of exposure to elevated levels of natural radiation on the microbiology of surface water samples. Water samples were collected from surface water streams in Talesh Mahalleh district, Ramsar as well as a nearby area with normal levels of background radiation. Only two strains of bacteria, that is, Providencia stuartii and Shimwellia blattae, could be isolated from the water samples collected from high background radiation areas, while seven strains (Escherichia coli, Enterobacter asburiae, Klebsiella pneumoniae, Shigella dysenteriae, Buttiauxella agerstis, Tatumella punctuata and Raoultella ornithinolytica) were isolated from the water samples collected from normal background radiation areas. All the bacteria isolated from water samples of high and normal background radiation areas were sensitive to ultraviolet radiation, heat, betadine, alcohol, and deconex. Although other investigators have reported that bacteria isolated from hot springs show radioresistance, the results reported here do not reveal any adaptive response.

Introduction: Staphylococcus aureus produces a range of virulence factors such as toxic shock syndrome toxin-1. Methods:
In this cross-sectional study of 345 clinical S. aureus isolates, the presence of the tst gene was assessed by polymerase chain
reaction (PCR). Results: The study revealed 53/345 (15.4%) isolates were positive for the tst gene. The tst gene was present
in 18.1% of methicillin-susceptible S. aureus (MSSA) isolates and 11.6% of methicillin-resistant S. aureus (MRSA) isolates
(p = 0.136). Conclusions: These results reveal the remarkable risk of S. aureus infections in hospitals, regardless of methicillinresistance
status.

Meningitis is a serious inflammation of the meninges, mainly caused by bacteria. Treatment of this life threatening disease should not be delayed; therefore, rapid empirical antibiotic therapy should be immediately started. Antimicrobial therapy based on early Cerebrospinal Fluid (CSF) examination has an important role in limitation of bacterial meningitis. Objectives: The current study aimed to identify the prevalence of etiological agents of bacterial meningitis and their susceptibility patterns against commonly used antibiotics. Patients and Methods: This cross-sectional study was performed within a two-year period 2011-2013 on all patients with suspected meningitis referring to Nemazee Hospital, Shiraz, Iran. Cerebrospinal fluid specimens were collected aseptically, and conventional methods were employed to isolate and identify the bacteria. Antimicrobial susceptibility tests were performed using disk diffusion method according clinical and laboratory standards institute (CLSI) recommendation. Results: Out of 2229 suspected meningitis cases, 255 (11.4%) were detected as positive culture. Most of the isolates were Gram-positive cocci, which 116 (45.5%) were Staphylococcus epidermidis, and 20 (7.8%) identified as Streptococcus spp. Among Gram-negative isolates, Escherichia coli and Acinetobacter spp., each with 19 isolates (5.9%), were predominant. Overall, the most effective antibiotics against Gram-positive cocci were vancomycin (91.5%), chloramphenicol (75.2%), and gentamicin (59.3%), respectively. Gram-negative isolates were mostly susceptible to gentamicin (65.1%), chloramphenicol (42.9%), and ciprofloxacin (39.7%), respectively. Conclusions: Gram-positive cocci, such as (Coagulase-Negative Staphylococci) CoNS and aerobic Gram-negative bacilli, were identified as the common etiologic agents of bacterial meningitis. Since the majority of these isolates was part of the normal flora and considered as opportunistic nosocomial infections, it is required to consider the importance of infection control programs in the healthcare centers.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a major cause of nosocomial infections. Methicillin resistance in S. aureus is caused by the acquisition of the mecA gene, located on a mobile genetic element called the staphylococcal cassette chromosome (SCC). Objectives: The aim of this study was to evaluate the presence of the predominant SCCmec type present among clinical isolates. Materials and Methods: This cross-sectional study was performed on a total of 146 MRSA isolates obtained from clinical specimens between 2012 and 2013 from two major hospitals in Shiraz, Southwest of Iran. Antibiotic susceptibility profiles were determined by the disc diffusion method according to the guidelines of The Clinical and Laboratory Standards Institute. Bacterial DNA was extracted using the small-scale phenol-chloroform extraction method and was employed as polymerase chain reaction (PCR) templates for the assigned current SCCmec types. Results: The assigned SCCmec types by PCR revealed the SCCmec type I as the predominant type with 86 (58.9%) samples, followed by the SCCmec type II with 29 (19.9%), type III with 16 (11.0%), and type IV with 12 (8.2%) samples, respectively. The SCCmec type I MRSA isolates were significantly recovered from blood (80%) and sputum (67.2%). The results of antibacterial susceptibility tests for the MRSA isolates showed that all of those carrying the SCCmec type I and II had significantly greater resistance rates to Gentamicin and Rifampin than the isolates containing the SCCmec type III. Also, a significant difference was detected for susceptibility to Co-trimoxazole between the SCCmec type I and II MRSA isolates and the SCCmec type III, which was more resistant. Conclusions: The frequency of the isolates containing type I in the current study can indicate an emergence of this SCCmec type in the studied medical centers.

Introduction: Biofilm producing Staphylococcus aureus is known as one of the major causative agents of infections, failure of implanted devices and persistent infection among hospitalized patients. The aim of the present study was to determine the frequency of biofilm producing S. aureus isolates amongst the clinical specimens. Methods: This cross-sectional study was conducted during 2012 to 2013 in two teaching hospitals in Shiraz, southwest of Iran. Totally, 345 S. aureus isolates from various clinical specimens were included. Biofilm producing isolates were phenotypically detected using Congo Red Agar (CRA) and genotypically by PCR assay for the icaA and icaD genes. Results: Of the 345 S. aureus isolates, 42.3% were methicillin-resistant S. aureus (MRSA) and subsequently 57.7% were methicillin susceptible isolates. The results of CRA plates showed that 77 (52.7%) and 74 (37.2%) of MRSA and MSSA were biofilm producing isolates. The frequency of icaA/D genes among MRSA and MSSA iso...

Background: Tuberculosis (TB) is the leading cause of mortality among human immunodeficiency virus (HIV) patients and the majority of them occur in developing countries. The aims of the present study were to determine the frequency of HIV/TB co-infection and other probable associated factors. Methods: This 10 year retrospective study was conducted on 824 HIV patients in the south-west of Iran. HIV infection was diagnosed by the enzyme linked immunosorbent assay and confirmed by Western blot. TB diagnosis was based on consistency of the clinical manifestations, chest X-ray, and microscopic examination. Drug susceptibility testing was done by the proportional method on Löwenstein-Jensen media. Results: Of 824 HIV patients, 59 (7.2%) were identified as TB co-infected and the majority (86.4%) of them were male. Of the overall TB infected patients, 6 cases (10.2%) showed multidrug-resistant with the mean CD4+ lymphocyte count of 163±166 cells/mm 3 . The main clinical forms of TB were pulmonary (73%). There was a significant (p<0.05) correlation between TB infection and CD4+ lymphocyte counts ≤200 cells/mm 3 , gender, prison history, addiction history, and highly active anti-retroviral therapy. Conclusion: We reported novel information on frequency of HIV/TB co-infection and multidrug resistant-TB outcome among co-infected patients that could facilitate better management of such infections on a global scale.

Background: Antimicrobial resistance is a growing problem in many bacterial pathogens
and is of particular concern for hospital-acquired nosocomial infections. Klebsiella
pneumonia is an important cause of nosocomial infections has rapidly become the most
common extended spectrum beta-lactamases (ESBLs) producing organism. ESBL are
defined as the enzymes capable of hydrolyzing oxyimino-cephalosporins. The aim of
this study was to compare phenotypic detection of ESBL using two phenotypically
method among the clinical isolates of Klebsiella pneumoniae.
Methods: In this cross-sectional study a total of 144 isolates from clinical samples
Urine, sputum, wound, blood, throat and body fluids isolated and identified as K.
pneumoniae in a teaching hospitals in Shiraz within a six months period from December
2012 to May 2013. Antibacterial susceptibility test performed to 14 antibiotics by
the disk diffusion method according to CLSI guideline and then isolates that were resistant
to at least one of the beta-lactam antibiotics evaluated for the production of betalactamase
enzymes by using E-test ESBL and combined disk method.
Results: Totally 38 (26.3%) isolates produced ESBLs. All ESBL producing isolates
were susceptible to imipenem and meropenem and resistant to aztreonam. The highest
antibiotic resistance was observed for amoxicilin (100%) and the lowest antibiotic resistance
was observed for meropenem (9.7%). The number of 38 (100%) isolates were
identified as ESBL producer by using E-test ESBL ceftazidime. It was while using the
combined disks; ceftazidime/clavulanic acid, cefotaxime/clavulanic acid and cefpodoxime/
clavulanic acid, respectively 35 (92.1%), 34 (89.4%) and 31 (81.5%) of isolates
identified as beta-lactamase producing isolates.
Conclusion: Considering the high prevalence of bacteria producing ESBL, screening
for infections caused by ESBL-producing isolates may be lead to the most effective antibiotics
therapies.

Background: Pseudomonas aeruginosa is considered as a major cause of hospital-acquired infections due to its high antibacterial resistance. Biofilm formation is a well-known pathogenic mechanism in P. aeruginosa infections, since sessile bacteria are protected in an extracellular matrix of exopolysaccharide. The expression of polysaccharide synthesis locus (pslA gene) can be important for biofilm formation by P. aeruginosa.
Objectives: The purpose of this research was to evaluate the antibiotic resistance pattern and distribution of the pslA gene among biofilm-producing P. aeruginosa isolates obtained from waste water of Burn Centre in Guilan, Iran.
Materials and Methods: Fifty isolates of P. aeruginosa were obtained from waste water of a burn center. The P. aeruginosa isolates were identified using standard bacteriological procedures. Drug susceptibility test was performed by disk diffusion method for all the isolates against nine antimicrobial agents. Biofilm formation was measured by microtiter plate assay. Polymerase chain reaction (PCR) was used to identify the presence of the pslA gene among the isolates.
Results: Biofilm formation was observed in 70% of the P. aeruginosa isolates. The potential formation of biofilm was significantly associated with resistance to gentamicin, imipenem, tobramycin and piperacillin. In addition, the pslA gene only existed in biofilm-producing isolates with a frequency of 42.9% (n = 15).
Conclusions: The findings of the present study well demonstrated that the P. aeruginosa biofilm-producing isolates were more resistant to the tested antibiotics. Furthermore, because of wide distribution, it seems that the pslA gene is associated with biofilm formation.

Background: Sepsis refers to an illness resulting from a systemic inflammatory response to infection, mainly caused by bacterial agents. Any delay in sepsis treatment can lead to high morbidity and mortality.
Objectives: The aims of this study were to identify the common bacterial agents responsible for pediatric septicemia and determine their antimicrobial susceptibility patterns in Nemazee Hospital, Shiraz, Iran.
Patients and Methods: This cross-sectional study was conducted within a two year period (2011 - 2013) for all patients with clinical manifestations of septicemia. Blood specimens were collected aseptically in BACTECTM blood bottles, and conventional bacteriological methods were followed for isolation and identification of the bacteria. Antimicrobial susceptibility tests were performed by using the disk diffusion method in accordance with CLSI recommendations.
Results: From a total of 491 blood cultures, 74 (15.1%) samples were detected as positive. The most common isolates were Gram positive cocci, and Staphylococcus epidermidis (48.6%) was found to be the most common Gram positive cocci. Among recovered Gram negative isolates, Acinetobacter spp. (8.1%) were the predominant isolates. Overall, the most effective antibiotics against Gram positive cocci were vancomycin (98%) and chloramphenicol (72.5%). In addition, the highest sensitivities to the agents tested against Gram negative isolates were to ciprofloxacin (47.8%) and chloramphenicol (30.4%).
Conclusions: Due to the variable nature of antibiotic susceptibility patterns and etiological agents of septicemia, continual assessment of the most frequent pathogens associated with bloodstream infections and detection of their sensitivity patterns to locally available antibiotics seem to be reasonable measures.