نشریه میکروب شناسی پزشکی ایران
سال سوم شماره 2 (تابستان و پاییز 1388)

Ziehl-Neelsen stain is an initial route in diagnosis of pulmonary tuberculosis. Some studies show the sensitivity and specificity of the methods of liquid media culture in rapid diagnosis of the disease. In this study, we evaluated the correlation between Microscopic Observation Drug Susceptibility culture, Ziehl-Neelsen stain and Lowenstein-Jensen culture of sputum in suspected pulmonary tuberculosis patients. This was a descriptive study with the technique of observational-interview type.One hundred patients from Masih Daneshvari hospital were considered as pulmonary TB suspects. One early morning sputum sample was obtained from each patient and used for Ziehl-Neelsen stain, culture on Lowenstein-Jensen medium and MODS culture for drug susceptibility testing. On sputum examination, 40% of patients were smear positive by Ziehl-Neelsen stain, while 30% had positive sputum culture for Mycobacterium tuberculosis in Lowenstein-Jensen medium and 47% had positive MODS culture. This research showed a significant and direct correlation between MODS culture with Lowenstein-Jensen media (r=+0.39, P<0.0001). There was a significant association and a significant and reverse correlation between MODS culture with pleural effusion(r=-0.23 P<0.05). Multidrug resistance was observed in 55% of patients. Prevalence of positivity of these diagnostic methods among MDR patients was lower. There was a significant and direct correlation between MDR diseases with MODS culture.(r=+0.96 P<0.0001) due to increasing of MDR tuberculosis, rapid determination of resistance pattern is very important which is possible by using MODS culture method. However, since lower positivity of MODS culture is obtained in MDR patients, Lowenstein-Jensen culture method should be done as complementary method in suspected pulmonary tuberculosis patients.

Currently the conventional method for the diagnosis of Listeria monocytogenes is culture method. However, the isolation rate is reduced in culture due to animal's food which is contains antibiotics. Besides, culture method is time consuming and takes more than 36 hrs. So more precise and rapid technique is needed. The aim of this study was application of PCR technique based on hlyA gene fragment for rapid detection of Listeria monocytogenes in clinical samples. hlyA gene was selected as a specific target sequencefor detection of Listeria monocytogenes. Listeria monocytogenes PTCC1163 was used as a standard organism for optimization experiments. A range of bacterial pathogens was used for specificity test including Escherichia coli: ATCC;35218 Salmonella typhi PTCC: 1609. Phenol – chloroform method was used for DNA extraction. PCR technique was performed as per standard protocol. Amplified product was detected by 1% gel agarose electrophoresis, stained by ethidiome bromide. Provided data confirmed amplification of expected product. Specificity test proved no cross reaction with tested organisms. Sensitivity test detected 500fg Listeria monocytogenes DNA as a final detection limit. Optimized experiment confirmed that the applied PCR protocol is quite fast with high sensitivity and specificity performing in less than three hours.Application of this method in clinical laboratories can help the rapid diagnosis of Listeria monocytogenes in samples.

Although Helicobacter pylori is known as a causative agent of gastritis, but due to its acidic tolerance characteristic, it seems that this species has ability to colonize the genital system. This may increase the risk of infertility among women. The aim of thepresent study was to determine the frequency of H. pylori in fertile and infertile women to find out the correlation between the H. pylori infection and infertility in women. In this cross-sectional study, 250 women including 131 infertile (cases) and 119 fertile (control) were taken under investigation. Blood was collected from each person and proceeded for detection of both IgG and IgM using ELISA. In addition, vaginal swabs was prepared for detection of Helicobacter using PCR technique. Data analysis was performed using Chi-square and T-tests. Among 259 samples tested, 158 (63.2%) were positive for H. pylori IgG comprises 65.54%(78) of cases and 61.1 %(80) of controls (p=0.463), but all the samples were negative for IgM. Vaginal swabs from cases and controls were all negative for H. pylori in PCR. Among cases,the causative factors for infertility was as following: 26 (70.2%) Polycystic Ovarian (PCO), 18 (52.5%) tubal factor, 21 (50%) unknown factor and 3 cases (100%) ovarian factor(OF).Statistical analysis revealed that the majority of IgG positivity were in individuals of 30-40 years age range (case and control 61.2% and 63.6% respectively), however it was not significant (P >0.05). Although the average IgG titer was found higher in infertile women but it was not significant. So, it seems that there is no correlation between the H. pylori infection and infertility. However, cases with PCO factor showed higher antibody titer when compared to other causative factors. Is it possible that this factor play a role in infertility?

During the last decade, enterococci have become important nosocomial pathogens, representing the second leading cause of urinary tract infections. This increasing prevalence has been paralleled by the occurrence of multi-drug resistant (MDR). The aim of this cross-sectional prevalence study was to determine the prevalence and risk factors of antibiotic resistance of Enterococcus faecium isolated from clinical samples in hospitalized patients in Kashan, Iran. This descriptive study was done on clinical specimens isolated from hospitalized patients, from September 2007 to 2008. A total of 106 E. faecalis strains were isolated from collected specimens. Antimicrobial susceptibility test was determined with disk diffusion method as per CLSI instructions. The minimal inhibitory concentration of vancomycin assayed by E test. From 128 isolated enterococci, 106(82.8 %) were identified as Enterococcus faecalis and 22 (17.2%) were Enterococcus faecium. According to the results of susceptibility testing, the resistance rates for E.faecalis were as follows: erytromycin 56(52.8%), ciprofloxacin 43(40.6%), gentamicin 41(38.7%),levofloxacin 36(34%), penicillin 31(29.2%), nitrofurantoin 20(18.8%), ampicillin 12(11.3%), Imipenem11(10.4%), and vancomycin 6(4.7%). All isolates were sensitive to linezolid. Multidrug-resistant (MDR) phenotype (resistance to three or more of drugs) occurred in 40(37.7%) of the isolates. Emergence of multidrug-resistant E.faecalis and high level resistance to vancomycin shown by E.faecalis strains is of concern because of the limitation in the therapeutic options for treatment of infections caused by enterococci.

Monolaurin is one of the main triglycerol monoesters of acid lauric, which has inhibitory effect on broad spectrum of bacteria. In order to enhance the antibacterial effect of monolaurin, some chelating agents such as EDTA and acidifiers are used. The aim of this study was to evaluate the inhibitory effects of monolaurin on Staphylococcus aureus and the effects of organic materials on reduction of monolaurin inhibitory effect in meat products. At first, minimum inhibitory concentration (MIC) of monolaurin alone and in combination with EDTA and lactic acid on staphylococcus in nutrient broth was investigated, then the inhibitory effect of monolaurin alone on bacteria was studied in sterile meat along with antibacterial effect of monolaurin and EDTA on unsterile meat. Data were analyzed using Variance test (ANOVA). MIC for monolaurin, monolaurin and EDTA and monolaurin and lactic acid were 32,16 and 8 μg/ml, respectively. The inhibitory effect of monolaurin alone on bacteria in sterile meat reduced significantly. Combination with lactic acid increased the effect of monolaurin on bacteria in sterile meat, but,monolaurin in combination of EDTA in unsterile meat did not show significant antibacterial effect. based on these findings, monolaurin can be used as food preservative in order to prevent food spoilage. The organic materials in the meat product could prevent the antibacterial effect of monolaurin. In addition chelating agents could enhance the antibacterial effect of monolaurin.

AlproCid is a brand new disinfectant which is a third Alkyl amine and ammonium with considerable effectiveness. The aim of this study was to evaluate of effectiveness of AlproCid on disinfecting dental surfaces and instruments. This laboratory-based study was conducted of 30 samples which were collected before and after administration of AlproCid from the same spots on dental instruments by using sterile swabs. The samples were cultured on blood agar and chocolate agar and were incubated in 37 oC for 24 hours.The standard bacteria were then identified to species level. The AlproCid solution was incorporated into strile paper discs. The effect of AlproCid was investigated by observation of growth inhibition zone around the disc and colony counting. The data was analyzed by using SPSS version 14 and Chi-Square test for determining the significance level and alpha error was set at 0.05%. From the total samples 86% were free of any bacteria. Microbial load was significantly reduced (P<0.05) after AlproCid application on dental instruments. The colony counting for all bacteria were reduced to less than 105, and the growth inhibition zone was at least 10 mm.This in vitro study showed the effectiveness of AlproCid on laboratory standard strains of E. coli, Klebsiella, Proteus, Entrococci resistant to vancomycin, and S. aureus resistant to methicillin. This effect was bactericidal. AlproCid is an effective agent in decreasing bacterial contamination of dental instruments without any adverse effect on the surface of instruments. The solution could be used for easy and rapid disinfecting of all surfaces.

The patients admitted in the ICU, have dysfunctions in one or more organs,especially, respiratory and cardiovascular systems. ICU is burdened with virulent bacteria and often highly resistants. Methicillin resistant Staphylococcus.aureus (MRSA) is one of important problem in the ICUs.The world-wide importance of “MRSA” encourage us to propose this study. The aim of this study wasto determine the prevalence of methicillin- resistant S.aureus colonization in patients hospitalized in ICUs in Qazvin’s university hospitals. This study occurred out during 6 months period (July through December,2006). Nasal swab specimens were collected on the admission and the discharge of patients admitted in ICUs university hospitals of Qazvin. After isolation and identification the strains, the methicillin resistance was determined by Clinical and laboratory standards institute(CLSI) oxacillin screening plate method. Other information were collected by uestionnaire. The data were analyzed by Chi-square and Fisher exact tests. A total number of 265 patients (1 day to 88 years old) were studied. The carrier state of methicillinsensitive S. aureus (MSSA), and MRSA strains were 52 (19.6%), and 32 (12.4%) respectively. Cultures from 174 (65.7%) patients were negative. From this 174 remainder, on discharging 11 (6.3%), and 40 (23%) patients were colonized with MSSA, and MRSA strains respectively. Ceftriaxone was more administrated antibiotic. There was a significant correlation between colonization with MRSA strains and length of ICU stay (P<0.05). Although colonization happened more to patients, who had “diabet”, urinary catheter, and prescription of “ceftriaxon”, but we found no significant relationship (P>0.05). Our findings confirm the presence of MRSA strain in population in Qazvin city. The incidence of colonization with MRSA strain, in comparison of the carrier state with the same strain, was 1.9 times. The ICUs wards are contaminated with this strain and so spreads among community. MRSA colonization had a significant association with length of ICU stay.

Nosocomial infections are an important public health problem in many developing countries, particularly in the intensive care unit (ICU). These infections are accompanied with longer hospitalization, higher therapy expenses and emerging drug resistance among bacterial causative agents. The aim of this study was to determine the prevalence of gram negative bacteria caused nosocomial infection in ICU of Besat hospital and detection of their antibiotic resistance pattern.This project was a descriptive cross- sectional study conducted during a period of 12 months in 2007 at ICU of Besat hospital. Bacterial strains were isolated from various clinical samples of the patients and were identified at the species level by using conventional methods. The susceptibility testing was performed on the isolated bacteria by disc diffusion method. Chi square test was used for data analysis. In this study, nosocomial infections by gram negative bacteria were identified in 65 out of 165 patients. So the incidence rate of nosocomial infection in this ward was 39.39%. The most prevalent isolated organism was Klebsiella pneumoniae (46.2%) followed by Escherichia coli (23.1%). Pneumonia (78.5%) was the most common infection in patients. The most effective antibiotics were cefotaxime clavonic acid,ceftazidime clavonic acid, amikacin and imipenem. All the isolates showed 80 to 100% resistance to ampicillin. The history of surgery and antibiotic therapy showed significant correlation with nosocomial infection (P<0.05). the most prevalent isolated bacteria was Klebsiella pneumoniae and the most common infection was pneumonia. High antibiotic resistance was seen in isolated bacteria in present study. Nosocomial infection showed significant correlation with a history of surgery and antibiotic therapy.

Contamination of hands plays an important role in the development of nasocomial infections, so surgical hand scrub is an important factor in control of infection. This study was performed to comparison two methods of surgical hand scrub and surgical hand rub on hands’ microbial burden of surgical team. The present clinical trial was performed during year 1999. Subjects were randomly selected from members of surgical team in 4 operation rooms of Qazvin. The subjects were divided into two groups of routine hand scrub and hand rub. From each subject, finger and thumb tip culture were performed on solid medium (Blood agar) and broth medium prior to hand wash. The second sampling were performed similarly after routine hand wash based on traditional surgical scrub with iodine in group 1 and hand rub which washind hands with non antibacterial soap and then surgical hand rub with 70% ethanol in 3 minute in group2. The effect of both disinfection procedures on microbial burden of hands were then compared. The data were analyzed using Chi square, MC Nemar and pierson statistical tests. Statistical analysis showed the significant differences between the amount of grown fingertips colonies before and after in both methods (P = 0 / 00). However we found no significant statistical difference (p=0.53) between the microbial hand counts following the use of either disinfection procedures and both disinfections were effective in reducing microbial hand counts.Conclusions-: The findings of this study support the proposition that a surgical hand rub protocol with alcohol is as effective and can replace the traditional surgical hand scrub; Information about hand hygiene and increased availability of alcohol-based hand rub led to improved hand hygiene at all levels of staff.

Cytomegalovirus is one of the most important viruses that its presence in transplant recipients has been surveyed. This virus can led to the severe disease or death. The prevalence of CMV infections in transplant recipients varies from one country to another. Indirect immunofluorescent method represents the virus multiplication and active infection, while PCR technique shows the presence ofvirus. The aim of this study was to determine the prevalence of active CMV infection in kidney transplant recipients using PCR and indirect immunofluorescent methods based on the season, age, and sex variables. samples from kidney recipients admitted to Gholhak laboratory during year 2006 and 2007 from all over Iran. This study was performed using PCR technique and indirect immunofluorescent method (PP65 antigenemia assay). The results were analyzed by Chi2 and lojestic regression. In total 923 samples were investigated. Seventy one (7.7%) and 323(35%) of samples were positive by antigenemia and PCR respectively. There was no correlation between CMV infection and age or sex of the patients (p >0.05). However there was a correlation between presence of virus and season in either used methods of study, which was statistically significant in the spring. The spring has meaningfull (p =0.01). Positive results obtained by PCR were more than antigenemia and this shows the higher sensitivity of this method to detect viral infection. we found no correlation between viral infection and sex or age by tested methods, but the infection rate had significant increase during spring.

One of the most common problems in the hospitals is the appearance of the resistant infections to the antimicrobial agents. Bacteriophages can use as an alternative to antibiotics for preventing and treating bacterial infections. Bacteriophages are viruses that infect and kill bacteria. They are safe; having no activity against animal or plant cells and appears to have evolved with bacteria as they are ubiquitous in nature. The aim of present study was isolation and enrichment of bacteriophages againstantibiotic resistant Pseudomonas aeruginosa isolates. Clinical samples from patients hospitalized in different wards of Ghaem Hospital (Mashhad, Iran) were collected and 43 antibiotic-resistant Pseudomonas aeruginosa were obtained from the samples. Appropriate lytic bacteriophages were isolated from refined sewage of the septic ward of the samehospital and bacteriocidal effect of the bacteriophages was evaluated in both liquid and solid phases. All tests were three times repeated in different bacteriophage concentrations under different conditions.The results were analyzed using statistical mann-witney test. By using two methods; solid and liquid phase the high concentration of prepared bacteriphages showed complete bactericidal effects on antibiotic-resistant isolated bacteria (p<0.0001). Our data showed the high efficacy of bacteriophages disinfectant effects and it was more prominent in the higher concentration of the bacteriophages.

Seronegative women's fetuses are at high risk of congenital toxoplasmosis if the first mother's infection occurs during pregnancy. We determined the seroprevalence of Toxoplasma gondii in order to highlight the risk and also preventive measures for pregnant women whom admitted in maternity ward of Kowsar hospital in Qazvin. 255 sera from pregnant women were examined for toxoplasma antibodies by indirect fluorescent antibody test (IFAT) for eight dilutions (1:20 to 1:6400). The necessary information including age, frequency of parity, abortion, contacts with cat, blood group (ABO system), Rh, source of water and the location of settlement (urban/rural) were gathered in a prepared questionare. Chi-square andT-test were used for data analysis. Anti-toxoplasma antibodies with titre higher than 1:20 were detected in 160 samples (62.7%).Although, there was no significant statistical correlation between toxoplasma seropositivity and determined variables in present study (P>0.05). in present study, 95 (37.3%) of women were seronegative whom potentially at risk of acquired acute toxoplasmosis in pregnancy meanwhile and possibility of parasite transmission to their fetuses may led to congenital toxoplasmosis. They ought to learn some healthy and applicable methods to decrease the risk of toxoplasmosis.