Genotypic analysis of E. coli strains isolated from patients with cystitis and pyelonephritis

Urinary tract infection is the most common health problem affecting millions of people each year, mainly caused by a large genetically heterogeneous group of Escherichia coli called uropathogenic E. coli. This study investigates the genotypic analysis of E. coli strains isolated from patients with cystitis and pyelonephritis. During 2008-2009, 90 E. coli strains were analyzed, consisting of 48 isolates causing pyelonephritis in children and 42 isolates causing cystitis. Having identified the strains by standard methods, they were subtyped by pulsed field gel electrophoresis [PFGE] and their corresponding patterns were compared using dendrogram. Sixty five PFGE profiles were obtained from the genome of E. coli strains by this genotyping method. Thirty six and thirty three patterns were obtained for pyelonephritis and cystitis, respectively. Most strains exhibited twelve and thirteen bands and the patterns with eight or nineteen bands had the lowest rate. Genome sizes of the strains were between 1610-4170 kbp. With due attention to these results, genetic patterns showed that the strains had different clonalities and it could be suggested in some cases that the strains causing pyelonephritis or cystitis have common patterns and different diseases could be explained by different gene factors

Susceptibility of Candida species isolated from immunocompromised patients to antifungal agents

This study was carried out from October 2003 to March 2007 to investigate susceptibility patterns to antifungals of Candida strains isolated from 410 immunocompromised patients in Shiraz, Islamic Republic of Iran. Patients were checked for systemic candidiasis. Fungal colonization was determined and clinical samples collected from those patients with clinical signs of infections were examined. The carbohydrate assimilation patterns of all 354 isolates were studied. Susceptibility of the isolates to antifungal agents was determined using the reference broth microdilution method. Candida Candida albicans was the species most often isolated. Voriconazole was highly active against all the isolates. Major resistance to itraconazole was observed in all Candida spp. Regular investigations into antifungal resistance in medical centres is highly recommended as this will result in more efficient management of invasive candidiasis in immunocompromised patients

Association of virulent genes hly, sfa, cnf-1 and pap with antibiotic sensitivity in Escherichia coli strains isolated from children with community-acquired UTI

Recent studies have suggested that the decrease in the pathogenicity of E. coli is due to acquisition of resistance to some antibiotics. This study was performed to investigate four virulence factors of pap, cnf-1, sfa and hly in resistant E. coli and compare them with susceptible strains of the bacteria isolated from children with community-acquired UTI. Drug sensitivity of 96 E. coli isolates was evaluated using a disc diffusion method. The prevalence of virulence genes was determined by PCR. E. coli strains showed a high degree of sensitivity to imipenem, amikacin, nitrofurantoin and ciprofloxacin. Approximately, 80.2% of the isolates were resistant to ampicilin. Only 12.5% of the strains were susceptible to all tested antibiotics. PCR showed that cnf-1 [22.9%] was more prevalent than hly [15.6%] and among adhesion coding genes, pap [30.2%] was more prevalent than sfa [18.8%]. In all strains, the expression of all virulent genes was less prevalent in most antibiotic resistant groups than in susceptible ones but not statistically significant except for genotypes of pap[+]-cnf[+], pap[+]- hIy[+] and cnf[+]-hly[+] with nalidixic acid. We propose that pap and cnf-1 genes in combination with hly gene constitute an uropathogenic genomic configuration which is the characteristic of the nalidixic-acid susceptible E. coli strains, causing urinary tract infection

Antibiotic-resistant bacteria in hospitalized patients with bloodstream infections: analysis of some associated factors

Blood infections are life-threatening if not detected and managed properly. This study investigates the correlation between fever and previous antibiotics therapy with differential time to positivrty [DTP] at admitted patients at Nemazee Hospital in Shiraz, southern Iran. From January 2005 to December 2006, 985 positive blood samples in Bactec bottles from the admitted patients at Nemazee Hospital were analyzed. Sensitivity patterns of the bacteria to a panel of antibiotics were determined by the disk diffusion method. S. epidermidis, S. aureus and Acinetobacter were the most prevalent isolates respectively. However, only 100 [20.7%] S. epidermidis samples were the true infections. The most susceptible Gram positive and negative bacteria were S. viridance, S. aureus, H. influenzae, and Brucella spp., respectively. Imipenem, amikacin and ciprofloxacin were the effective ones against Gram negative bacteria, while vancomycin, co-amoxiclav and chloramphenicol were effective against Gram positive ones. Cefuroxime and penicillin G were less effective antibiotics against both Gram negative and positive bacteria. As demonstrated, the combined prescription of vancomycin and imipenem seems to cover the majority of infective agents in the blood whenever an empirical therapy is to be initiated. Moreover, periodic surveillance of antibacterial susceptibility patterns is warranted

[Risk Factors of nasal carriage of methicillin-resistant staphylococcus aureus and its antibiotic susceptibility pattern in Namazi hospital healthcare workers in Shiraz, Iran]

Methicillin-resistant Staphylococcus aureus [MRSA] is a major nosocomial pathogen worldwide. The aim of this study was to determine the risk factors of nasal carriage of MRSA and its antibiotic susceptibility pattern among healthcare workers at Namazi Hospital [Shiraz-Iran]. In a cross-sectional study from July to November 2006, nasal swabs were taken from 600 stratified randomly selected health care workers. The isolates were identified as S. aureus based on morphology, gram stains, catalase test, coauglase test and DNase Agar. To differentiate Methicillinsusceptible S. aureus [MSSA] and Methicillin Resistant S. aureus [MRSA], agar screen plate was used. All methicillin-resistant isolates were examined for mecA genes existence by PCR performance. The sensitivity patterns of S.aureus isolates were determined by disc diffusion and E-test method. Nasal screening identified 186 [31%] S. aureus carriers of whom, 154 ones [82.8%] were MSSA and 32 ones [17.2%] were MRSA. There was no significant association between related risk factors and gender, age, years of healthcare service and level of education. In the univariate analysis, a statistically significant difference was found only based on occupation [P=0.032] between carriers of MSSA and MRSA. In multivariate analysis [logistic regression], having nursing occupation [p=0.012, OR=3.6, 95%CI=1.3-9.7] was independently associated with MRSA carriage. All of the MRSA strains were sensitive to mupirocin. This study revealed that having nursing occupation is independently associated with MRSA carriage since all S.aureus isolates were susceptible to mupirocin, topical mupirocin could be used successfully to eradicate nasal staphylococcal colonization and carriers

Pseudomonas aeruginosa: burn infection, treatment and antibacterial resistance

Pseudomonas aeruginosa is an opportunistic pathogen causing severe, acute and chronic nosocomial infections in immunocompromised, catheterized or burn patients. Various types of virulent factors have been identified in P. aeruginosa, suggesting their contribution to the pathogenesis of the disease. The organism is generally resistant to numerous antimicrobial agents due to natural resistance in particular impermeability or mutations and acquisition of resistant determinants. Plasmid and integron have a crucial role in acquisition of mobile elements. Most treatment failures are related to inappropriate initial antibiotic therapy with insufficient coverage of multidrug resistant [MDR] pathogens, the rationale for using combinations of antibiotics to cover MDR gram-negatives. However, clinical data supporting this strategy are limited. In fact, systematic combination therapy may have contributed to the overuse of antibiotics and to the emergence of MDR microorganisms. Nevertheless, combination therapy is the best strategy to treat severe infections due to suspected MDR Pseudomonas. Optimally, therapeutic strategies should be sufficiently broad to cover relevant pathogens while minimizing the risk for emergence of antimicrobial resistance. Polymyxin E [colistin] and carbapenems are the most effective antibiotics against MDR isolates

Helicobacter pylori and extradigestive disorders in the past 10 years

While the association between Helicobacter pylori and other digestive conditions are still under the study, some authors have also investigated an expanding list of the studies on the role of H. pylori as a pathogenic determinant of some extraduodenal idiopathic diseases, such as cardiovascular, immunological, skin, liver, biliary tract, and various other disorders. Although it is still unclear how a localized infection may affect areas distant from the site of infection, it is supposed that H. pylori gastric infection may cause systemic illnesses through immunemediated mechanisms. This idea is based on the following points: [i] local inflammation can have systemic effects; [ii] gastric H. pylori infection is a chronic process that lasts for decades; [iii] persistent infection induces chronic inflammatory and immune responses that can cause lesions that are local or distant from the site of primary infection. In the past 10 years, an increasing number of studies concerning the association between H. pylori infection and extradigestive conditions have been reported. Most of these studies have documented the H. pylori infection by serology and Urease Breath Test [UBT], and rarely by PCR, and no one could isolate any H. pylori microorganism from samples, using culture method. Of course, the culture of this fastidious organism is extremely difficult; if not impossible. In this study, some of the recent papers are reviewed to find new scopes for the role of H. pylori in some kinds of extradigestive diseases

[Discrimination of dominant H. pylori strains isolated from patients with different gastroduodenal pathologies by protein profiling]

It is not clear what factors determine divergent outcomes of infections caused by H. pylori. The aim of this study was to differentiate H. pylori strains isolated from the patients with different gastroduodenal pathologies by protein profiling. The protein profiles of different strains of H. pylori isolated from 3 groups of patients with ulcerative disease, nonulcerative gastritis and cancer disease were analyzed using 1D-SDS-PAGE. Based on the highly divergent protein patterns, the similarity of the strains inside each group was 75%, 76.47% and 78.57% for cancerous, ulcerative and no ulcerative groups respectively, while about 30.76% of the protein bands were common in all strains isolated from three groups of the patients. Some of the observed bands were significantly specific for each group. We speculated that some H. pylori strains might be more associated with a specific disease than others, leading to the clustering of some, but not all, strains within each disease group. This study showed that protein profile can be a criterion used for discriminating of dominant states in different gastric clinical states. Specific and dominant proteins of different strains isolated from three groups of patients under the study could be welcome candidates for further exploration to be used both for laboratory tests, which analyze disease-specific H. pylori strains, and for diagnosis of different diseases and outcomes associated with this widespread bacterium