Phenotypic and Molecular Epidemiology of Acinetobacter calcoaceticus baumannii Complex Strains Spread at Nemazee Hospital of Shiraz, Iran.

BACKGROUND: Acinetobacter calcoaceticus baumannii (ACB) complex are Gram-negative opportunistic bacteria with low virulence properties. Their resistance to antibiotics has become a matter of concern in hospital infections. OBJECTIVES: The present study aimed to determine the prevalence and antimicrobial susceptibility of ACB isolates collected from the Nemazee hospital of Shiraz. In addition, Pulsed Field Gel Electrophoresis (PFGE) was used to determine the genetic patterns of these strains. PATIENTS AND METHODS: In this cross-sectional study, 93 strains of ACB complex were isolated from patients of Nemazee hospital, Shiraz, Iran. The antibiotic susceptibility patterns of the isolates to the following 15 antibiotics were determined: gentamicin, ticarcillin, ceftazidime, co-trimoxazole, imipenem, piperacillin tazobactam, amikacin, aztreonam, sulbactam, meropenem, tobramycin, cefotaxime, ceftriaxone, colistin, polymyxin B. Pulsed Field Gel Electrophoresis was used to determine the clonal relationship of these strains. RESULTS: Most of the isolates were found to be resistant to cefotaxime, co-trimoxazole, ceftriaxone, aztreonam, ceftazidime and ticarcillin (90%), and the least resistance was observed to colistin and polymyxin B. Among the 93 tested samples, 35 antimicrobial susceptibility patterns and 47 PFGE patterns were obtained. CONCLUSIONS: High resistance to antibiotics was observed among the strains of ACB complex and the least resistance was towards colistin and polymyxin B, indicating that these antibiotics could be effective for treatment, in case there is no other choice. Using PFGE, the similarity between some strains of Acinetobacter was determined, which indicated epidemics in different parts of the hospital; such epidemics can in turn lead to increased incidence of Acinetobacter infections.

Isolation and Antibiotic Susceptibility of the Microorganisms Isolated from Diabetic Foot Infections in Nemazee Hospital, Southern Iran.

Background. Diabetic foot infections (DFIs) are a major public health issue and identification of the microorganisms causing such polymicrobial infections is useful to find out appropriate antibiotic therapy. Meanwhile, many reports have shown antibiotic resistance rising dramatically. In the present study, we sought to determine the prevalence of microorganisms detected on culture in complicated DFIs in hospitalized patients and their antibiotic sensitivity profiles. Methods. A cross-sectional study was conducted for a period of 24 months from 2012 to 2014 in Nemazee Hospital, Shiraz, Iran. The demographic and clinical features of the patients were obtained. Antimicrobial susceptibility testing to different agents was carried out using the disc diffusion method. Results. During this period, 122 aerobic microorganisms were isolated from DFIs. Among Gram-positive and Gram-negative bacteria, Staphylococcus spp. and E. coli were the most frequent organisms isolated, respectively. Of the isolates, 91% were multidrug while 78% of S. aureus isolates were methicillin resistant. 53% of Gram-negative bacteria were positive for extended-spectrum ß-lactamase. Conclusion. Given the involvement of different microorganisms and emergence of multidrug resistant strains, clinicians are advised to consider culture before initiation of empirical therapy.

Burn Patients Infected With Metallo-Beta-Lactamase-Producing Pseudomonas aeruginosa: Multidrug-Resistant Strains.

BACKGROUND: Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa in the burn patients is a leading cause of morbidity and mortality and remains a serious health concern among the clinicians. OBJECTIVES: The aim of this study was to detect MBL-producing P. aeruginosa in burn patients and determine multidrug-resistant (MDR) strains, and respective resistance patterns. PATIENTS AND METHODS: In this cross-sectional study, 270 strains of P. aeruginosa were isolated from the burn patients referred to Ghotbeddin Burn Hospital, Shiraz, Iran. Among them, 55 MBL-producing P. aeruginosa strains were isolated from 55 patients hospitalized in burn unit. Minimum inhibitory concentrations (MICs) and MBLs were determined by the E-test method. RESULTS: Of the 55 burn cases, 29 (53%) were females and 26 (47%) males. Injured burn patients' ages ranged from 16 to 87 years, with maximum number of cases in the age group of 16 to 36 years (n, 40; 72.7%). Overall, 32 cases were accidental (60%), and 22 were suicidal burns (40%). Of the 55 burn patients, 17 cases were expired (30%). All deaths were due to chemical exposures. In antibiotic susceptibility testing by E-test method, ceftazidime was the most effective one and 35 isolates (63.5%) were resistant to all the 11 tested antibiotics. CONCLUSIONS: Routine microbiological surveillance and careful in vitro testing of antibiotics prior to prescription and strict adherence to hospital antibiotic policy may help to prevent, treat, and control MDR and pandrug-resistant (PDR) P. aeruginosa strains in burn units.

Antibiotic Susceptibility Patterns and Molecular Epidemiology of Metallo-ß-Lactamase Producing Pseudomonas Aeruginosa Strains Isolated From Burn Patients.

BACKGROUND: Failure in the treatment of burn patients infected with Pseudomonas aeruginosa could happen as a result of the acquisition of antibiotic resistance, including carbapenems. OBJECTIVES: The aim of the present study was to investigate the phenotypic and genotypic characteristics of the Pseudomonas aeruginosa strains, isolated from burn patients. PATIENTS AND METHODS: During a 12 month period, in this cross-sectional study, two hundred seventy strains of Pseudomonas aeruginosa were isolated from the burn patients in Ghotbeddin Burn Hospital, Shiraz, Iran. Screening for the carbapenem resistance in the isolates was carried out by the E test method. Sensitivity patterns of metallo-ß-lactamase (MßLs) producing strains of pseudomonas to eleven antibiotics were determined by the mentioned method. The epidemiological associations of these strains were determined by Pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 270 strains, 60 (22.2%) were resistant to imipenem and meropenem, classified as MßLs producing. MßLs producing strains of pseudomonas were completely resistant to five tested antibiotics while their sensitivities to the three most effective antibiotics including ceftazidime, amikacin and ciprofloxacin were 23.4%, 6.7 % and 1.7%, respectively. In PFGE, 37 patterns from the genome of Pseudomonas aeruginosa were observed. Majority of the strains (43; 71.6%) exhibited more than 80% similarity, based on the drawn dendrogram. CONCLUSIONS: According to the results, none of the tested antibiotics is safe to prescribe. As PFGE revealed, a limited number of Pseudomonas aeruginosa types are predominant in the hospitals which infect the burn patients.

Antifungal susceptibility of the aspergillus species by Etest and CLSI reference methods.

BACKGROUND: Because resistance to antifungal drugs is seen in patients, susceptibility testing of these drugs aids in choosing the appropriate drug and respective epidemiology. This study has investigated and compared susceptibility patterns of the Aspergillus species isolated from patients by the Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (MD) assay and Etest method. METHODS: The minimum inhibitory concentrations (MICs) of various antifungal agents (amphotericin B, ketoconazole, itraconazole, and voriconazole) for 108 Aspergillus species isolated from patients were determined by CLSI M38-A broth MD and Etest. The isolates were obtained from clinical samples that included tissues, sputum, bronchoalveolar lavage, abdominal tap, and cerebrospinal fluid. RESULTS: As revealed by the MD method, 63.9% of the isolates were sensitive to amphotericin B and 36.1% were resistant.Etest revealed that 61.1% were sensitive to amphotericin B and 38.9% were resistant. As for ketoconazole, 108 isolates (100%) were shown to be sensitive through the MD method; while the Etest revealedan 88.9% sensitivity and 11.1% were resistant. All species were susceptible to voriconazole, according to both methods. The measure of agreement (Kappa Index) for these three drugs was satisfactory (≥0.6). According to the MD method, 69.4% of the species were susceptible to itraconazole, whereas 30.6% were not.For this drug, the Etest showed 86.1% susceptible and 13.9% resistant. CONCLUSION: Voriconazole was the most effective agent against isolates. Using RPMI agar, we found the Etest to be helpful, readily available, and easy to use for determining invitro susceptibilities of Aspergillus species to voriconazole, amphotericin B, ketoconazole, and itraconazole in the region of this study.

Microbial susceptibility, virulence factors, and plasmid profiles of uropathogenic Escherichia coli strains isolated from children in Jahrom, Iran.

BACKGROUND: Urinary tract infections (UTIs), including cystitis and pyelonephritis, are the most common infectious diseases in childhood. Escherichia coli (E. coli) accounts for as much as 90% of the community-acquired and 50% of nosocomial UTIs. Therefore, identification of E. coli strains is important for both clinical and epidemiological implications. Understanding antibiotic resistance patterns and molecular characterization of plasmids and other genetic elements is also epidemiologically useful. METHODS: To characterize uropathogenic strains of E. coli, we studied 96 E. coli strains recovered from urine samples of children aged 1 month to 14 years with community-acquired UTIs in Jahrom, Iran. We assessed virulence factors (VFs), drug sensitivities, and plasmid profiles. RESULTS: Drug sensitivities of the isolates were: 19.8% (ampicillin), 24% (trimethoprim-sulfamethoxazole), 29.2% ( tetracycline), 75.5% (nalidixic acid), 80.4% (cefixime), 84.6% (gentamicin), 91.4% (ciprofloxacin), 96.8% (nitrofurantoin), 96.8% (amikacin) and 100% (imipenem). Totally, 76 isolates harbored plasmids with an average of 5.5 plasmids (range: 1-10) in each strain. Plasmid profiling distinguished 22 different E. coli genotypes in all isolates that ranged in similarity from 50% to 100%. PCR showed that the prevalence of virulence genes ranged from 15.62% for hly to 30.2% for pap. CONCLUSION: These data mandate local monitoring of drug resistance and its consideration in empirical therapy of E. coli infections. Plasmid analysis of representative E. coli isolates also demonstrates the presence of a wide range of plasmid sizes, with no consistent relationship between plasmid profiles and resistance phenotypes. Plasmid profiles distinguished more strains than did the antimicrobial susceptibility pattern.

Vancomycin utilization evaluation at hematology-oncology ward of a teaching hospital in iran.

The aim of the present study was to evaluate the pattern of vancomycin administration in the hematology-oncology ward of Nemazee Hospital, Shiraz, Iran. Study criteria were developed to assess the several parameters involved in vancomycin therapy. These parameters include the appropriateness of drug usage, dosage, duration of therapy, monitoring for toxicity and serum concentration monitoring. The serum concentration was measured by an automated Fluorescence Polarization Immunoassay. Clinical and preclinical parameters such as Glomerular Filtration Rate (GFR), microbial culture, antibacterial sensitivity, WBC count and fever were collected and recorded for analysis. Sixty patients were enrolled in the study, consisting of 45 males and 15 females. The age range was 15 to 68 years. In this study, 68.63% of the vancomycin used for the patients with febrile neutropenia was compatible with the Infectious Disease Society of America (IDSA) guideline. The initial dosage of vancomycin in 68.63%, rate of infusion in 100%, and dilution of vancomycin in100%, were appropriate. Inappropriate use was more evident in the continuation of vancomycin in 50% of the patients. No appropriate dosage adjustment was done for 50% of the patients with increased serum creatinine. Based on the results, the indication of vancomycin in febrile neutropenia was satisfactory. However, there were some required factors such as continuation of vancomycin, adjustment of dosage or interval, microbial culture, antibiotic sensitivity test before the first dose administration, measurement of serum concentration and monitoring which had to be revised in order to achieve an effective treatment.

Antibacterial susceptibility patterns of Porphyromonas gingivalis isolated from chronic periodontitis patients

Objectives: To test the antimicrobial sensitivity of Porphyromonas gingivalis to a panel of eight orally administrable antibiotics in chronic periodontal diseases and to evaluate factors associated with periodontitis in adultpatients.Study Design: A total of fifty strains of P. gingivalis were isolated from one hundred and twenty adult patients with chronic perio-dontitis. Identification of bacteria was carried out by anaerobic culture and biochemical tests.Selected colonies of P. gingivalis were used to evaluate the antibacterial activities of penicillin, metronidazole,amoxicillin, amoxicillin/clavulanic acid, clindamycin, doxy-cycline, ciprofloxacin and azithromycin.Results: Most of the patients were female, age ranging between 40 to 50 years. Majority of the patients frequently had scaling and depths of periodontal pockets in infected teeth were 5-8 mm and most of them had hemorrhageduring sampling. Susceptibility testing revealed a sensitivity of 100% of P. gingivalis to azithromycin, doxycyclineand amoxicillin/clavulanic acid but lower susceptibilities were found for the rest of antibiotic agents evaluated.Conclusions: Frequent scaling in women aged between 40-50 years had positive correlation with chronic periodontitis.The application of antibiotics in conjuction with mechanical debridation, may reflect in the level of resistance of P. gingivalis in patients with chronic periodontal infections. This could suggest periodical antibiotic susceptibility testing is necessary to determine the efficacy of antimicrobial agents if the perfect curing of chronicperiodontal diseases after mechanical debridation is meant. Further clinical studies are required to confirm thein vitro results. The only limitation in this study was identification of bacteria to species rather than subspecies level (AU)

An improvement in isolation and preservation of clinical strains of Helicobacter pylori.

BACKGROUND AND AIM: Isolation of H. pylori from gastric mucosal biopsy specimens is a prerequisite for further studies addressing drug susceptibility testing, analysis and characterization of virulence factors, molecular epidemiology studying or other comparative studies. In this study, we used a modified enriched culture medium with short incubation time to improve the isolation rate of H. pylori from the clinical specimens. METHODS: Between October 2008 and October 2009, 266 dyspeptic patients attending the endoscopy ward of Motahhary Clinic of Shiraz University of Medical Sciences, were investigated. The biopsy samples were cultured on two selective media called M1, which we used in our previous studies, and a modified medium called M2. The cultures were kept in a microaerophilic atmosphere at 37 degrees C. The plates were inspected first on day 1, and then on daily basis for a total of 10 days. The isolates were confirmed as H. pylori by colony morphology and positive oxidase, catalase and rapid urease tests. We used the same media and culture conditions to subculture the isolates for several times. Specimens were considered to be H. pylori positive if either the culture or two of the three diagnostic methods yielded positive results. RESULTS: The isolation rate of H. pylori strains from the samples was significantly higher on M2 in comparison with M1 medium (p<0.05). The bacterial growth on M2 was observed after a significantly shorter time (p<0.05), i.e., after incubation for about 24 hrs. Following these procedures, the preservation time could be extended beyond 6 months without a significant loss of viability. CONCLUSION: The modified culture technique enabled a shorter incubation time and a higher isolation rate for H.pylori obtained from clinical samples.

Association between existence of integrons and multi-drug resistance in Acinetobacter isolated from patients in southern Iran.

Nosocomial infections caused by multi-drug resistant Acinetobacter pose a serious problem in many countries. This study aimed at determining the antibiotic susceptibility patterns and prevalence of different classes of integrons in isolated Acinetobacter. In addition, the association between production of specific bands in PCR assay and magnitude of multi-drug resistance was investigated. In total, 88 Acinetobacter strains were isolated from patients from October 2008 through September 2009. The Minimal inhibitory concentration (MIC) of 12 antibiotics conventionally used in clinics against the isolates, was determined by E-test method. The existence of integron classes was investigated by PCR assay through the amplification of integrase genes. The most effective antibiotic against Acinetobacter was colistin with 97.7% activity, followed by imipenem (77.3%) and meropenem (72.7%). The presence ofintegron classes 1 and 2 in 47 (53.4%) isolates was confirme, However, no class 3 was detected. The proportion of class 1, compared with class 2, was high (47.7% vs. 3.4%). The association between multi-drug resistance to norfloxacin, ceftazidime, gentamicin, ciprofloxacin, cefepime and amikacin and the presence of integrons was statistically significant. However, the association was not remarkable in many of the isolates which exhibited resistance to the rest of antibiotics. This may imply that in addition to integrons, other resistance determinants such as transposon and plasmid may also contribute to resistance. To reduce the pressure on sensitive isolates, comprehensive control measures should be implemented. Furthermore, wise application of effective antibiotics could help alleviate the situation. Colistin is the most effective antibiotic in vitro against Acinetobacter.

Antibacterial susceptibility patterns of Porphyromonas gingivalis isolated from chronic periodontitis patients.

OBJECTIVES: To test the antimicrobial sensitivity of Porphyromonas gingivalis to a panel of eight orally administrable antibiotics in chronic periodontal diseases and to evaluate factors associated with periodontitis in adult patients. STUDY DESIGN: A total of fifty strains of P. gingivalis were isolated from one hundred and twenty adult patients with chronic perio-dontitis. Identification of bacteria was carried out by anaerobic culture and biochemical tests. Selected colonies of P. gingivalis were used to evaluate the antibacterial activities of penicillin, metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin, doxy-cycline, ciprofloxacin and azithromycin. RESULTS: Most of the patients were female, age ranging between 40 to 50 years. Majority of the patients frequently had scaling and depths of periodontal pockets in infected teeth were 5-8 mm and most of them had hemorrhage during sampling. Susceptibility testing revealed a sensitivity of 100% of P. gingivalis to azithromycin, doxycycline and amoxicillin/clavulanic acid but lower susceptibilities were found for the rest of antibiotic agents evaluated. CONCLUSIONS: Frequent scaling in women aged between 40-50 years had positive correlation with chronic periodontitis. The application of antibiotics in conjuction with mechanical debridation, may reflect in the level of resistance of P. gingivalis in patients with chronic periodontal infections. This could suggest periodical antibiotic susceptibility testing is necessary to determine the efficacy of antimicrobial agents if the perfect curing of chronic periodontal diseases after mechanical debridation is meant. Further clinical studies are required to confirm the in vitro results. The only limitation in this study was identification of bacteria to species rather than subspecies level.

Ventilator-associated pneumonia in Iranian intensive care units.

INTRODUCTION: Nosocomial pneumonia (NP) and ventilator associated pneumonia (VAP) occur most frequently in intensive care units (ICU). This study seeks to determine the etiological agents of NP and VAP along with their antibacterial susceptibility patterns, and to evaluate the factors contributing to patient mortality. The impact of appropriate therapy in terms of three parameters (body temperature, PaO2/FiO2 ratio and leukocyte count) was also assessed. METHODOLOGY: This study involved 836 adult patients admitted to ICUs at the Nemazee Hospital, Shiraz, Iran, over nine months during 2008 and 2009. The inclusion criterion was the commencement of infection at least 48 hours following hospital admission. Clinical parameters including core temperature, leukocyte count. and PaO2/FiO2 ratio were evaluated. Antibiotic sensitivities of the isolated bacteria to a panel of antibiotics were determined using E-test. RESULTS: Of 836 cases, only 58 (6.9 %) cases of NP were diagnosed, of which 42 (72 %) were VAP. A. baumannii, MRSA, P. aeruginosa and MSSA were the most prevalent bacteria. Significant correlations between previous antibiotic therapy (p = 0.04), use of corticosteroids (p = 0.02) and attributable mortality were found. A strong correlation between fever abatement and the ratio of PaO2/FiO2 with responses to treatment and outcomes was also evident. CONCLUSIONS: Combined treatment with meropenem/imipenem, ciprofloxacin and vancomycin seems to be appropriate and could cover all possible infective agents. To reduce mortality rate, reasonable prescription of antibiotics and corticosteroids could be effective. Furthermore, adopting a strategy to reduce body temperature and PaO2/FiO2 ratio could be beneficial in patients' outcomes.

Characterization of SCCmec types and antibacterial susceptibility patterns of methicillin-resistant Staphylococcus aureus in Southern Iran.

A total of 156 methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients hospitalized in southern Iran were tested for staphylococcal cassette chromosome mec (SCCmec) types and antibacterial susceptibility patterns between May 2008 and May 2009. Type III SCCmec was the most prevalent (116, 74.3%), followed by mec types A (147 bp only; 11, 7.1%), IVa (8, 5.1%), IVc (7, 4.5%), IVd and V (4, 2.6%), and II (1, 0.6%). Class A mec and type III ccr and mec complexes were also predominant. All isolates were found to be sensitive to vancomycin, teicoplanin, linezolid, quinupristin-dalfopristin, mupirocin, and fusidic acid. However, reduced sensitivity of these MRSA isolates to other antibiotics, including rifampin, co-trimoxazole, clindamycin, cephalexin, tetracycline, ciprofloxacin, erythromycin, and gentamicin, was also observed. The predomination of type III SCCmec could be due to the antibiotic pressure which facilitated its clonal selection and dissemination. The present findings are indicative of the existence of community-acquired types (IV, V) in the hospitals studied, therefore comprehensive and periodic control measures and rational prescription of appropriate antibiotics are highly recommended to reduce antibiotic resistance.

Antimicrobial susceptibility of Helicobacter pylori strains isolated from patients in Shiraz, Southern Iran.

AIM: To improve our understanding of Iranian regional variation in Helicobacter pylori (H. pylori) antibiotic resistance rates to find the best antibiotic therapy for eradication of H. pylori infections. METHODS: A total of 266 patients undergoing endoscopy in Shiraz, Southern Iran, were included in this study. H. pylori strains were isolated from antral biopsies by culture and confirmed by the rapid urease-test and gram staining. Antibiotic susceptibility of H. pylori isolates was determined by E-test. RESULTS: A total of 121 H. pylori strains were isolated, 50 from male and 71 from female patients. Data showed that 44% (n = 53), 20% (n = 24), 5% (n = 6), and 3% (n = 4) of all strains were resistant to the antibiotics metronidazole, amoxicillin, clarithromycin, and tetracycline, respectively. When the antibiotics were considered together we found 11 sensitivity patterns for the strains. Resistance to metronidazole was significantly higher in female than in male patients (P < 0.05). In about 71% of the metronidazole-resistant isolates, the minimum inhibitory concentrations (MICs) exceeded 256 µg/mL. CONCLUSION: We found a moderate rate of primary resistance to metronidazole. However, a high MIC (> 256 mg/L) which was found in 71% of the isolates is considerable. In the case of amoxicillin, an increased resistance rate of 20% is worrying. Resistance to clarithromycin and tetracycline is also emerging among the H. pylori strains in our region.

Antibacterial susceptibility patterns and cross-resistance of methicillin resistant and sensitive Staphyloccus aureus isolated from the hospitalized patients in Shiraz, Iran

Nosocomial infections caused by methicillin-resistant staphylococci (MRSA) pose a serious problem in many countries. This study aimed to determine the antibacterial susceptibility patterns of methicillin sensitive and resistant Staphylococcus aureus isolates from the hospitalized patients. Totally 356 isolates of Staphylococcus aureus (S. aureus) including 200, 137 and 19 corresponding to MSSA, MRSA, and intermediate MRSA strains, respectively were isolated. Antibacterial susceptibility patterns of the isolates to 14 antibiotics were examined using Kirby-Bauer method. MICs of 15 antibiotics to 156 MRSA isolates were determined by E test method. Cross-resistances of MRSA isolates (137+19) to the other tested antibiotics were also determined. S.aureus with high frequencies were isolated from the blood, sputum and deep wound samples. All of 200 MSSA isolates were sensitive to oxacillin, vancomycin, tecoplanin, rifampin, linezolid, quinupristin/dalfopristin, mupirocin and fusidic acid. A gradient of reduced susceptibility of MSSA to cephalexin, co-trimoxazole, ciprofloxacin, clindamycin, tetracycline, erythromycin and gentamicin were evident. MRSA isolates were sensitive to vancomycin, tecoplanin, linezolid, quinupristin/dalfopristin, mupirocin and fusidic acid, while reduced susceptibility of them to rifampin, co-trimoxazole, clindamycin, cephalexin, tetracycline, ciprofloxacin, erythromycin and gentamicin were observed. MRSA isolates exhibited a high range of cross-resistance to the eight tested antibiotics. Overall, co-trimoxazole, ciprofloxacin, clindamycin, tetracycline, erythromycin and gentamicin showed low activity against MSSA and MRSA isolates which may indicate they are not suitable to be used in clinical practices. To preserve the effectiveness of antibiotics, rational prescription and concomitant application of preventive measures against the spread of MRSA are recommended.

IL-1ß (+3953 C/T) and IL-8 (-251 A/T) gene polymorphisms in H. pylori mediated gastric disorders.

BACKGROUND: Previous studies imply that IL-1 and IL-8 gene variations may play a crucial role in the genetic predisposition to different gastric disorders upon H. pylori infection. OBJECTIVE: The aim of this study was to determine the potential association between the prevalence of certain polymorphic sites and the risk of gastric disorders in Iranian population. METHODS: One hundred and forty three unrelated individuals with different gastric disorders and 374 normal individuals with no gastric disorders and with a negative serology test for H. pylori (control group) were studied for the association between IL-1ß (+3953 C/T) and IL-8 (-251 A/T) gene polymorphisms and H. pylori-mediated gastritis and gastric ulcer. An analysis of genotype frequency for these genes was performed using RFLP-PCR. RESULTS: Based on the data obtained from culture and pathologic findings, the patients were classified into three subpopulations: H. pylori(+) non-ulcerative gastritis(+), H. pylori(+) ulcerative gastritis(+) and H. pylori(-) non-ulcerative gastritis(+). A significantly higher frequency of TT genotype (p=0.02) in IL-1ß +3953 in H. pylori(+) ulcerative gastritis(+) was revealed compared to the control group. There were no significant differences among other subpopulations. No significant differences in allele and genotype frequencies of IL-8 (-251A/T) were found among the patients. CONCLUSION: The data suggest that TT genotype in IL-1ß +3953 may be a major contributing genetic risk factor for H. pylori induced gastric ulcer. Moreover, the role of other bacterial and host response factors, such as bacterial adherence peptides, host chemokines, and genes involved in gastric acid secretion, must be further investigated in different ethnic populations.

Antibacterial susceptibility patterns and cross-resistance of methicillin resistant and sensitive staphyloccus aureus isolated from the hospitalized patients in shiraz, iran.

Nosocomial infections caused by methicillin-resistant staphylococci (MRSA) pose a serious problem in many countries. This study aimed to determine the antibacterial susceptibility patterns of methicillin sensitive and resistant Staphylococcus aureus isolates from the hospitalized patients. Totally 356 isolates of Staphylococcus aureus (S. aureus) including 200, 137 and 19 corresponding to MSSA, MRSA, and intermediate MRSA strains, respectively were isolated. Antibacterial susceptibility patterns of the isolates to 14 antibiotics were examined using Kirby-Bauer method. MICs of 15 antibiotics to 156 MRSA isolates were determined by E test method. Cross-resistances of MRSA isolates (137+19) to the other tested antibiotics were also determined. S.aureus with high frequencies were isolated from the blood, sputum and deep wound samples. All of 200 MSSA isolates were sensitive to oxacillin, vancomycin, tecoplanin, rifampin, linezolid, quinupristin/dalfopristin, mupirocin and fusidic acid. A gradient of reduced susceptibility of MSSA to cephalexin, co-trimoxazole, ciprofloxacin, clindamycin, tetracycline, erythromycin and gentamicin were evident. MRSA isolates were sensitive to vancomycin, tecoplanin, linezolid, quinupristin/dalfopristin, mupirocin and fusidic acid, while reduced susceptibility of them to rifampin, co-trimoxazole, clindamycin, cephalexin, tetracycline, ciprofloxacin, erythromycin and gentamicin were observed. MRSA isolates exhibited a high range of cross-resistance to the eight tested antibiotics. Overall, co-trimoxazole, ciprofloxacin, clindamycin, tetracycline, erythromycin and gentamicin showed low activity against MSSA and MRSA isolates which may indicate they are not suitable to be used in clinical practices. To preserve the effectiveness of antibiotics, rational prescription and concomitant application of preventive measures against the spread of MRSA are recommended.

Multidrug-resistant bacteria isolated from intensive-care-unit patient samples

We examined epidemiological aspects and bacterial resistance patterns of bacteria isolated from intensive care unit (ICU) patient samples. During a 10 month period (from June 2006 to March 2007), 812 samples of blood, urine and cerebral spinal fluid (CSF) from 553 hospitalized patients, in ICU wards, including pediatric surgical, neonatal, adult surgical I, adult surgical II, general pediatrics, neurosurgical I, neurosurgical II, and internal medical, were collected. Minimum inhibitory concentration (MIC) of antibiotics for bacteria isolates was determined by the E-test method. The internal medicine ICU with 28.7 percent admissions gave the largest contribution. Coagulase negative staphylococci at frequencies of 66.7 percent and 36.5 percent and E. coli at 20.9 percent were the bacteria most frequently isolated from the blood, CSF and urine samples, respectively. Samples taken from patients 20-40 years old were the most frequent (32.2 percent), while the group of patients over sixty years contributed least (18.5 percent). Both Gram-positive and - negative isolates expressed resistance to most of the penicillins and cephalosporins tested. Combined therapy with vancomycin and meropenem or imipenem gave the most effective treatment against Gram-positive and Gram-negative isolates based on empirical therapy. High frequencies of multiresistant bacteria in ICUs warn us to administer a few effective antibiotics in our hospitals more wisely in order to reduce selective pressure on sensitive strains. This could help save the life of ICU patients and prevent of spread of resistant isolates in these critical wards. Due to continuous changes in antibacterial susceptibility patterns, periodical antibacterial sensitivity assessment in ICUs should be mandatory.

Prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and its antibiotic susceptibility pattern in healthcare workers at Namazi Hospital, Shiraz, Iran.

OBJECTIVE: The aim of this study was to determine the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers (HCWs) at Namazi Hospital, Shiraz, Iran. METHODS: This cross-sectional study was conducted from July to November 2006. Nasal swabs were taken from 600 randomly selected HCWs. The isolates were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test, and mannitol salt agar fermentation. To analyze sensitivity patterns of MRSA strains more precisely, minimum inhibitory concentrations (MICs) of antibiotics were determined by the E-test method. All methicillin-resistant isolates were examined for the existence of the mecA gene by total DNA extraction and PCR. RESULTS: The prevalence of nasal carriage of methicillin-sensitive S. aureus (MSSA) was 25.7% and of MRSA was 5.3%, with the highest nasal carriage of MRSA in surgical wards and the emergency department. There was no significant difference between the sexes (p=0.247), age (p=0.817), and years of healthcare service (p=0.15) with regard to the nasal carriage of MRSA and MSSA. In the univariate analysis, a statistically significant difference was only found for occupation (p=0.032) between the carriage of MSSA and MRSA. In the multivariate analysis, the occupation 'nurse' was independently associated with MRSA carriage (p=0.012, odds ratio 3.6, 95% confidence interval 1.3-9.7). The highest resistance rate for both gentamicin and clindamycin (69%) was noted among the MRSA strains. None of the MRSA strains were resistant to mupirocin, linezolid, fusidic acid, or vancomycin. The existence of the mecA gene in all 32 methicillin-resistant isolates was observed by PCR. CONCLUSIONS: This study revealed the prevalence of nasal carriage of S. aureus strains among HCWs to be lower than that found in other studies from Iran. The antibiotic susceptibility patterns also differed, perhaps as a result of the excessive use of antibiotics at our hospital. Only the occupation of nurse was an independent risk factor for MRSA carriage.

Active immunization using exotoxin A confers protection against Pseudomonas aeruginosa infection in a mouse burn model.

BACKGROUND: Pseudomonas aeruginosa is an important cause of nosocomial infection and may lead to septicemia and death. We evaluated the immunogenicity of semi-purified exotoxin A from the bacterium in a mouse burn model. METHODS: The toxoid was prepared from exotoxin A taken from toxigenic strains of P. aeruginosa (PA 103). 50 mice were immunized with the toxoid, burned with hot metal and infected with 1 x 10(8) CFU of toxigenic strains of P. aeruginosa (experimental group); 25 non-immunized mice were also burned and infected (control group). The mortality rate and presence of any exotoxin and P. aeruginosa in the sera, liver and spleen were determined. RESULTS: In the experimental group, 2 mice died before the burns were administered and were excluded from the study. The remainder (48 mice) were challenged with a lethal dose of P. aeruginosa and followed for 70 days. 3 of these mice died. Neither P. aeruginosa nor exotoxin A was not detected in the liver, spleen or sera of the surviving mice. The protective efficacy of toxoid vaccination was therefore 93.8%. In the control group, all mice died from bacteremia and septicemia, most (80%) within 6 days, and P. aeruginosa and exotoxin A were isolated from sera, spleen and liver. CONCLUSION: Active immunization of mice using a semi-purified exotoxin A derived from P. aeruginosa was 93.8% effective at protecting mice from subsequent P. aeruginosa infections in a mouse burn model.