Latest medical literature on macrodantin

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Medical research on macrodantin

Antimicrobial resistance in community and nosocomial Escherichia coli urinary tract isolates, London 2005-2006.

Ann Clin Microbiol Antimicrob. 2008; 7: 13
Bean DC, Krahe D, Wareham DW
BACKGROUND: Escherichia coli is the commonest cause of community and nosocomial urinary tract infection (UTI). Antibiotic treatment is usually empirical relying on susceptibility data from local surveillance studies. We therefore set out to determine levels of resistance to 8 commonly used antimicrobial agents amongst all urinary isolates obtained over a 12 month period. METHODS: Antimicrobial susceptibility to ampicillin, amoxicillin/clavulanate, cefalexin, ciprofloxacin, gentamicin, nitrofurantoin, trimethoprim and cefpodoxime was determined for 11,865 E. coli urinary isolates obtained from community and hospitalised patients in East London. RESULTS: Nitrofurantoin was the most active agent (94% susceptible), followed by gentamicin and cefpodoxime. High rates of resistance to ampicillin (55%) and trimethoprim (40%), often in combination were observed in both sets of isolates. Although isolates exhibiting resistance to multiple drug classes were rare, resistance to cefpodoxime, indicative of Extended spectrum beta-lactamase production, was observed in 5.7% of community and 21.6% of nosocomial isolates. CONCLUSION: With the exception of nitrofurantoin, resistance to agents commonly used as empirical oral treatments for UTI was extremely high. Levels of resistance to trimethoprim and ampicillin render them unsuitable for empirical use. Continued surveillance and investigation of other oral agents for treatment of UTI in the community is required.

Urinary tract infections in pregnancy.

Can Fam Physician. 2008 Jun; 54(6): 853-4
Lee M, Bozzo P, Einarson A, Koren G
QUESTION: My pregnant patients often present with urinary tract infections. Are the medications commonly used for the management of urinary tract infections safe to use during pregnancy? ANSWER: Existing data indicate that exposure to penicillins, cephalosporins, fluoroquinolones, nitrofurantoin, or phenazopyridine during pregnancy is not associated with increased risk of fetal malformations. Trimethoprim-sulfamethoxazole should be avoided, if possible, during the first trimester of pregnancy because of the antifolate effect associated with neural tube defects.

Contemporary management of uncomplicated urinary tract infections.

Drugs. 2008; 68(9): 1169-205
Guay DR
Uncomplicated urinary tract infections (uUTIs) are common in adult women across the entire age spectrum, with mean annual incidences of approximately 15% and 10% in those aged 15-39 and 40-79 years, respectively. By definition, UTIs in males or pregnant females and those associated with risk factors known to increase the risk of infection or treatment failure (e.g. acquisition in a hospital setting, presence of an indwelling urinary catheter, urinary tract instrumentation/interventions, diabetes mellitus or immunosuppression) are not considered herein.The majority of uUTIs are caused by Escherichia coli (70-95%), with Proteus mirabilis, Klebsiella spp. and Staphylococcus saprophyticus accounting for 1-2%, 1-2% and 5-10% of infections, respectively. If clinical signs and symptoms consistent with uUTI are present (e.g. dysuria, frequency, back pain or costovertebral angle tenderness) and there is no vaginal discharge or irritation present, the likelihood of uUTI is >90-95%. Laboratory testing (i.e. urinary nitrites, leukocyte esterase, culture) is not necessary in this circumstance and empirical treatment can be initiated.The ever-increasing incidence of antimicrobial resistance of the common uropathogens in uUTI has been and is a continuing focus of intensive study. Resistance to cotrimoxazole (trimethoprim/sulfamethoxazole) has made the empirical use of this drug problematic in many geographical areas. If local uropathogen resistance rates to cotrimoxazole exceed 10-25%, empirical cotrimoxazole therapy should not be utilized (fluoroquinolones become the new first-line agents). In a few countries, uropathogen resistance rates to the fluoroquinolones now exceed 10-25%, rendering empirical use of fluoroquinolones problematic. With the exception of fosfomycin (a second-line therapy), single-dose therapy is not recommended because of suboptimal cure rates and high relapse rates. Cotrimoxazole and the fluoroquinolones can be administered in 3-day regimens. Nitrofurantoin, a second-line therapy, should be given for 7 days. beta-Lactams are not recommended because of suboptimal clinical and bacteriological results compared with those of non-beta-lactams. If a beta-lactam is chosen, it should be given for 7 days.Management of uUTIs can frequently be triaged to non-physician healthcare personnel without adverse clinical consequences, resulting in substantial cost savings. It can be anticipated that the optimal approach to the management of uUTIs will change substantially in the future as a consequence of antimicrobial resistance.

Nitrofurantoin resistance mechanism and fitness cost in Escherichia coli.

J Antimicrob Chemother. 2008 Jun 10;
Sandegren L, Lindqvist A, Kahlmeter G, Andersson DI
Objectives The biological fitness cost of antibiotic resistance is a key parameter in determining the rate of appearance and spread of antibiotic-resistant bacteria. We identified mutations conferring nitrofurantoin resistance and examined their effect on the fitness of clinical Escherichia coli isolates. Methods By plating bacterial cells on agar plates containing nitrofurantoin, spontaneous nitrofurantoin-resistant E. coli mutants were isolated. The fitness of susceptible and resistant strains was measured as growth rate in the presence and absence of nitrofurantoin in rich culture medium. Time-kill kinetics of the resistant mutants was compared with the susceptible strains. Resistance mutations were identified by DNA sequencing. Results Spontaneous resistant mutants of initially susceptible clinical E. coli appeared with a rate of 10(-7)/cell/generation, and these mutants showed a reduction in the growth rate compared with the susceptible parent strain. Similarly, comparison of a set of susceptible and resistant clinical isolates of E. coli showed that the average growth rate of the resistant mutants was approximately 6% lower than the susceptible strains. Furthermore, the bacterial growth rate in the presence of nitrofurantoin at therapeutic levels was greatly reduced even for nitrofurantoin-resistant mutants. The resistance-conferring mutations were identified in the nsfA and nfsB genes that encode oxygen-insensitive nitroreductases. Conclusions Nitrofurantoin resistance confers a reduction in fitness in E. coli in the absence of antibiotic. In the presence of therapeutic levels of nitrofurantoin, even resistant mutants are so disturbed in growth that they are probably unable to become enriched and establish an infection.

Asymptomatic bacteriuria in patients with diabetes mellitus in Ile-Ife, South-West, Nigeria.

East Afr Med J. 2008 Jan; 85(1): 18-23
Odetoyin WB, Aboderin AO, Ikem RT, Kolawole BA, Oyelese AO
OBJECTIVES: To investigate the prevalence and associates of asymptomatic bacteriuria (ASB) in a sample of Nigerian diabetic patients. DESIGN: Cross-sectional descriptive and analytic study. SETTING: The Wesley Guild Hospital and Ife State Hospital, both units of Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. SUBJECTS: One hundred and thirty five diabetic patients and 57 non-diabetic patients as controls. MAIN OUTCOME MEASURES: Demographic parameters of participants were recorded. Significant bacteriuria was determined for each of the mid-stream urine specimen obtained from all the subjects. Organisms isolated were identified and evaluated for antibiotic susceptibility patterns. RESULTS: There was a significant difference in the prevalence of ASB in the two groups. Prevalence of ASB was 16% and 3.5% in the diabetic patients and control respectively (p=0.03). Demographic parameters except age were not related to the presence of ASB. ASB was found in 54.4% of diabetic patients with poor glycaemia control compared with 2.9% in diabetics with good glycaemia control (p = 0.006). Organisms associated with ASB were Staphylococcus aureus, Klebsiella sp, Escherichia coli and Enterococcus faecalis, however the most predominant was Staphylococcus aureus. These organisms were largely resistant to the common antibiotics tested such as cotrimoxazole and gentamicin but susceptible to nitrofurantoin. CONCLUSIONS: The prevalence of ASB is high in diabetic patients and poor glucose control can be considered a predisposing factor.

Bactericidal activity of 2-nitroimidazole against the active replicating stage of Mycobacterium bovis BCG and Mycobacterium tuberculosis with intracellular efficacy in THP-1 macrophages.

Int J Antimicrob Agents. 2008 Jul; 32(1): 40-5
Khan A, Sarkar S, Sarkar D
This study evaluated the antituberculous potential of 2-nitroimidazole under in vitro conditions. Minimal bactericidal concentrations of the compound against actively replicating Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra were found to be 0.226mug/mL and 0.556mug/mL in enriched and minimal medium, respectively. Minimal inhibitory concentrations were >100 times lower than reported antituberculous nitroimidazoles such as nitrofurantoin and furaltadone, indicating the greater potential of 2-nitroimidazole. No discernible effect of 2-nitroimidazole was seen on saprophytic Mycobacterium smegmatis and the representative bacterial strain Escherichia coli DH5alpha, indicating the specificity of the molecule against tuberculous mycobacteria. The compound was also found to be effective against M. tuberculosis in the intracellular environment of the human monocytic cell line THP-1, with a reduction in viability of bacilli by 2.5 log after 144h of incubation at a concentration of 0.113mug/mL. A five-fold higher concentration (0.565mug/mL) of 2-nitroimidazole sterilised the macrophages of intracellular pathogens within 192h, without affecting the host. However, 2-nitroimidazole was unable to affect significantly the viability of dormant non-replicating bacilli of M. bovis BCG and M. tuberculosis in Wayne's in vitro model. Overall, the results indicate that 2-nitroimidazole is a potent antituberculous agent active against the organism's active replicating stage, with promising intracellular efficacy as well.

Antibiotic resistance pattern and empirical therapy for urinary tract infections in children.

Saudi Med J. 2008 Jun; 29(6): 854-8
Al-Harthi AA, Al-Fifi SH
OBJECTIVE: To study the type of bacterial pathogen causing urinary tract infection in children at Aseer Central Hospital, southwestern Saudi Arabia, and their antimicrobial resistance patterns. METHODS: A retrospective study of all the urine cultures carried out on children in the period from January 2003 to December 2006, for a total of 4 years were reviewed at the bacteriology laboratory, Aseer Central Hospital, southwestern region of Saudi Arabia. Their antimicrobial resistances as well as sensitivities were also analyzed. RESULTS: A total of 464 urine cultures were identified. Escherichia coli constitutes the most common pathogen isolated 37.3%, followed by Klebsiella 16.4% and Pseudomonas species 15.7%. In general, there was a significant increase in the resistance rates of different bacterial pathogens to different antibiotics. CONCLUSION: In spite of an increase in the resistance rates of bacterial pathogens causing UTI, ceftriaxone, imipenem, and to some extent Azactam are appropriate for initial empirical intravenous therapy in UTI. In patients with uncomplicated UTI not requiring hospitalization, Nalidixic acid, and Nitrofurantoin can be used as oral treatment.

Drug-induced interstitial pneumonia.

Prescrire Int. 2008 Apr; 17(94): 61-3

(1) Interstitial pneumonia usually develops gradually. The signs and symptoms are non-specific, and generally include dyspnea, cough, fatigue, and weight loss. In other cases onset is acute, sometimes beginning with a flu-like syndrome. Interstitial pneumonia can lead to acute respiratory failure, sometimes gradual deterioration of respiratory function, and pulmonary fibrosis progressing to respiratory failure. The fibrosis does not regress when the causal factor is withdrawn. (2) There are numerous causes of interstitial pneumonia, including medicinal drugs. (3) Amiodarone generally induces slow and insidious lung disease. (4) Methotrexate induces lung disease. Most cytotoxic drugs cause chronic dose-dependent lung disease and fibrosis, in some cases long after treatment cessation. (5) The many other implicated drugs include nitrofurantoin, Nonsteroidal antiandrogens, drugs that induce connective tissue diseases, laxatives based on mineral oil, and many other drugs, some of which are known to cause hypersensitivity reactions. (6) In practice, a drug-related cause should be kept in mind in cases of interstitial pneumonia, as symptoms generally improve after drug withdrawal, unless fibrosis has already started to develop.

5 days of nitrofurantoin was equivalent to 3 days of trimethoprim-sulfamethoxazole for women with non-complicated cystitis.

Evid Based Med. 2008 Jun; 13(3): 80
Fekete T

Risk factors in enterococci isolated from foods in Morocco: Determination of antimicrobial resistance and incidence of virulence traits.

Food Chem Toxicol. 2008 Apr 25;
Valenzuela AS, Omar NB, Abriouel H, López RL, Ortega E, Cañamero MM, Gálvez A
A collection of enterococci isolated from meat, dairy and vegetable foods from Morocco including 23 Enterococus faecalis and 15 Enterococcus faecium isolates was studied. All isolates were sensitive to ampicillin, penicillin, and gentamicin. Many E. faecalis isolates were resistant to tetracycline (86.95%), followed by rifampicin (78.26% ciprofloxacin (60.87%), quinupristin/dalfopristin (56.52%), nitrofurantoin (43.47%), levofloxacin (39.13%), erythromycin (21.73%), streptomycin (17.39%), chloramphenicol (8.69%), vancomycin (8.69%), and teicoplanin (4.34%). E. faecium isolates showed a different antibiotic resistance profile: a high percentage were resistant to nitrofurantoin (73.33%), followed by erythromycin (66.60%), ciprofloxacin (66.66%), levofloxacin (60.00%), and rifampicin (26.66%), and only a very low percentage were resistant to tetracycline (6.66%). One isolate was resistant to vancomycin and teicoplanin. The incidence of virulence factors was much higher among E. faecalis isolates, especially for genes encoding for sex pheromones, collagen adhesin, enterococcal endocarditis antigen, and enterococcal surface protein. Isolates with multiple factors (both antibiotic resistance and virulence traits) were also more frequent among E. faecalis isolates, in which one isolate cumulated up to 15 traits. By contrast, several isolates of E. faecium had only very few unwanted traits as compared to only two isolates in E. faecalis. The high abundance of isolates carrying virulence factors and antibiotic resistance traits suggests that the sanitary quality of foods should be improved in order to decrease the incidence of enterococci.