The role of Citrobacter in clinical disease of children: review.
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Various species of Citrobacter may cause infections in neonates and immunocompromised hosts. Citrobacter koseri (formerly Citrobacter diversus) is best known as the cause of sepsis and meningitis leading to central nervous system (CNS) abscesses in neonates and young infants. Early onset and late-onset infections occur as for other neonatal bacterial infections. The majority of cases are sporadic, with no clear source of infection. A few have been confirmed to be vertically transmitted, and nosocomial outbreaks have occurred in neonatal care units. The pathophysiology is not well understood, but a surface protein has been identified as a possible virulence factor among strains that cause citrobacter brain abscesses in neonates. Despite improvements in diagnostic imaging techniques, surgery, and antibiotic therapy, approximately one-third of infants with abscesses die, and one-half sustain CNS damage. In this article, the taxonomy, epidemiology, pathogenesis, diagnosis, treatment, and outcome of citrobacter disease in children are reviewed. (+info)
How intestinal bacteria cause disease.
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An improved understanding of how intestinal bacteria cause disease has become increasingly important because of the emergence of new enteric pathogens, increasing threats of drug resistance, and a growing awareness of their importance in malnutrition and diarrhea. Reviewed here are the varied ways that intestinal bacteria cause disease, which provide fundamental lessons about microbial pathogenesis as well as cell signaling. Following colonization, enteric pathogens may adhere to or invade the epithelium or may produce secretory exotoxins or cytotoxins. In addition, by direct or indirect effects, they may trigger secondary mediator release of cytokines that attract inflammatory cells, which release further products, such as prostaglandins or platelet-activating factor, which can also trigger secretion. An improved understanding of pathogenesis not only opens new approaches to treatment and control but may also suggest improved simple means of diagnosis and even vaccine development. (+info)
The characteristics of extended-spectrum beta-lactamases in Korean isolates of Enterobacteriaceae.
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Extended-spectrum beta-lactamases (ESBLs) in gram-negative organisms have been implicated as the enzymes responsible for resistance to oxyimino-cephalosporins. The incidence of ESBL-producers in Korean isolates of Escherichia coli and Klebsiella pneumoniae were in the range of 4.8-7.5% and 22.5-22.8%, respectively. The ESBL-producing isolates revealed variable levels of resistance to cefotaxime, ceftazidime and aztreonam. They also showed the elevated MIC values of non-beta-lactam antibiotics. SHV-12 and SHV-2a were the enzymes most frequently found in K. pneumoniae strains, but TEM-52 was the most prevalent in E. coli isolates. About 15% of ESBL-producing isolates of Enterobacteriaceae produced CMY-1 enzyme, which conferred resistance to cephamycins such as cefoxitin as well as oxyimino-cephalosporins. Thus, the most common types of ESBLs in Korea are TEM-52, SHV-12 SHV-2a, and CMY-1. (+info)
Citrobacter koseri meningitis in a special care baby unit.
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An outbreak of meningitis due to Citrobacter koseri in a special care baby unit is described. The organism showed a high capacity for spread among the babies on the unit and although the intestinal carriage rate was high, the clinical case:carrier ratio was low. (+info)
In-vitro susceptibility of 1982 respiratory tract pathogens and 1921 urinary tract pathogens against 19 antimicrobial agents: a Canadian multicentre study. Canadian Antimicrobial Study Group.
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A total of 3903 pathogens from 48 Canadian medical centres were tested against 19 antimicrobial agents. Five agents showed activity against > or = 90% of all 1982 respiratory tract pathogens tested (ciprofloxacin, 90%; cefoperazone, 91%; ticarcillin/clavulanate, 92%; ceftazidime and imipenem, 93% each). Nine agents had > or = 90% activity against Enterobacteriaceae from respiratory tract infection (cefotaxime and ticarcillin/clavulanate, 90% each; aztreonam, ceftizoxime and ceftriaxone, 91% each; ceftazidime, 93%; ciprofloxacin, 97%; imipenem and netilmicin, 98% each). Similarly, five agents had activity against > or = 90% of all 1921 urinary tract pathogens tested (ciprofloxacin and ticarcillin/clavulanate, 90% each; cefoperazone and netilmicin, 91% each; imipenem, 99%). Nine agents had > or = 95% activity against Enterobacteriaceae from urinary tract infection (ciprofloxacin, 95%; cefotetan, 97%; aztreonam, cefotaxime, ceftazidime, ceftizoxime, ceftriaxone and netilmicin, 98% each; imipenem, 99%). Seventeen agents had activity against > or = 95% of Staphylococcus aureus strains. Susceptibility of Pseudomonas aeruginosa isolates ranged from 2% to 91%. (+info)
The global epidemiology of resistance to ciprofloxacin and the changing nature of antibiotic resistance: a 10 year perspective.
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Many studies have examined the in-vitro activity of ciprofloxacin. The results are for the most part encouraging but we must guard against complacency. Levels of ciprofloxacin resistance vary geographically, while some predictably difficult-to-treat organisms such as Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter baumannii present challenges globally. The emergence of resistance in species previously exquisitely sensitive to ciprofloxacin, such as Neisseria gonorrhoeae, in countries associated with 'pirate' production and indiscriminate use of antimicrobials represents a major challenge. Ciprofloxacin continues to show excellent activity against Haemophilus influenzae and Moraxella catharralis. In general, ciprofloxacin shows good activity against Enterobacteriaceae although the emergence of reduced susceptibility and, sometimes, quinolone resistance in multi-resistant isolates should be noted. (+info)
Short-course therapy of acute cystitis: a brief review of therapeutic strategies.
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Acute cystitis is one of the commonest medical problems encountered by primary care physicians. It affects more women than men (8:1), but the incidence among men is increasing. Uncomplicated cystitis by definition occurs in healthy patients with a normal urinary tract, whereas complicated cystitis implies a predisposing or underlying condition. A narrow range of aetiological agents is responsible for most uncomplicated cystitis in women (Escherichia coli in 80% of cases). Recently, however, pathogens usually associated with sexually transmitted disease have been implicated. In women with typical symptoms of acute uncomplicated cystitis, an abbreviated laboratory work-up followed by empirical therapy is recommended. Single-dose and 3 day regimens of co-trimoxazole and the quinolones are as effective as longer regimens and have a higher eradication rate than other commonly used antimicrobials. Relapse rates are slightly higher with single-dose therapy. With this success rate plus the reduced cost and improved patient compliance, these regimens have replaced traditional 5 to 14 day courses of treatment. With increasing resistance of the common urinary pathogens to amoxycillin and, now, co-trimoxazole, the quinolones are a logical choice for empirical therapy of uncomplicated urinary tract infections. (+info)
Citrobacter rodentium infection in mice elicits a mucosal Th1 cytokine response and lesions similar to those in murine inflammatory bowel disease.
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Citrobacter rodentium is a classically noninvasive pathogen of mice that is similar to enteropathogenic Escherichia coli (EPEC) in man. Following oral infection of young mice, the organism colonizes the distal colon, and within 1 week the colonic mucosa doubles in thickness and there is massive epithelial cell hyperplasia. Since T-cell responses in mouse models of inflammatory bowel disease (IBD) also cause epithelial hyperplasia, we have investigated the possibility that C. rodentium promotes similar T-cell responses in the mucosa, thereby increasing epithelial shedding, transmission, and replication of the organism. Beginning 6 days after infection, bacteria were observed to be in close association with the epithelial surface and were also visible scattered throughout the lamina propria and in the submucosa. There was a CD3(+)-cell infiltrate into the colonic lamina propria and epithelium as well as mucosal thickening and crypt hyperplasia. The majority of CD3(+) cells were CD4(+) and were not gammadelta+. Reverse transcription-PCR analysis of cytokines also revealed a highly polarized Th1 response (interleukin-12, gamma interferon, and tumor necrosis factor alpha) in the mucosa and a large increase in the epithelial cell mitogen keratinocyte growth factor. None of the changes were seen in mice inoculated with bacteria lacking intimin (which is necessary for colonization), but they were seen in mice inoculated with C. rodentium complemented with intimin from EPEC. This is the first example of a classically noninvasive bacterial pathogen which elicits a strong mucosal Th1 response and which produces pathology similar to that seen in mouse models of IBD, which is also characterized by a strong Th1 response. These results also suggest that the colonic mucosa responds in a stereotypic way to Th1 responses. (+info)