Use of norfloxacin in the treatment of acute diarrheal disease

Lomefloxacin versus trimethoprim/sulfamethoxazole in the treatment of adults with acute bacterial diarrhea

This study compared the efficacy and safety of lomefloxacin with that of trimethoprim/sulfamethoxazole (TMP/SMX) in the treatment of adult patients with acute diarrhea of bacterial etiology. Two centers enrolled a total of 133 patients; 99 (74%) presented with severe symptoms. The patients were randomized to receive either lomefloxacin 400 mg once daily (n=68) or TMP/SMX 160/800 mg twice daily (n=65) for five days. Bacteriologic success was achieved in 89.5% of evaluation lomefloxacin-treated patients and in 97.5% of patients treated with TMP/SMX. Clinical success was achieved in 100% and 97.5% of patients in the two treatment groups, respectively. The predominant organisms isolated in both groups at baseline, i.e. Shigella flexneri, Vibrio parahaemolyticus, and Salmonella Group D, were eradicated in all patients. Campylobacter jejuni was isolated at baseline in four patients in the lomefloxacin group but in none randomized to receive TMP/SMX; this organism persisted in three patients. Adverse events were experienced by 14 (23%) of the lomefloxacin-treated patients and by 18 (30%) of the TMP/SMX-treated patients. All adverse events reported were mild or moderate in severity and their distribution was similar in both groups. The results of this study show that lomefloxacin 400 mg once daily is as effective as TMP/SMX 160/800 mg twice daily and suggest that lomefloxacin is a promising new quinolone for the treatment of bacterial diarrhea.

Efficacy of pefloxacin in the treatment of patients with acute infectious diarrhoea

OBJECTIVE

To investigate the clinical and bacteriological efficacy of 5- and 7-day pefloxacin therapy in patients with acute infectious diarrhoea.

PATIENTS AND STUDY DESIGN

Eighty-two adult patients with acute infectious diarrhoea were randomly divided into three groups: group 1 (n = 20) received 5 days of treatment with pefloxacin, group 2 (n = 27) was assigned to a 7-day pefloxacin protocol, and group 3 (n = 35) was treated symptomatically. The daily dose of pefloxacin was 400mg orally. Clinical and bacteriological response was analysed on the third, fifth and seventh days of treatment as well as 1 and 4 weeks after the end of treatment. The study was an open-labelled, prospective clinical trial.

RESULTS

In the 47 patients (100%) of both pefloxacin groups a clinical improvement was noted on the third day compared with the control group, where this occurred on day 7. Bacteriological eradication was verified on the fifth day in 18 patients (90%) from group 1 and in 25 patients (93%) from group 2; they all had negative stool cultures 1 and 4 weeks after therapy was completed. Only 22 patients (63%) in the control group had negative stool cultures on the seventh day of treatment, but 4 weeks later all of them were negative.

CONCLUSION

There was no difference in clinical (p = 0.232) and bacteriological (p = 0.972) efficacy between the 5- and 7-day pefloxacin treatment protocols. However, both protocols differed significantly in clinical improvement (p < 0.001) and bacteriological eradication (p = 0.017) from the control group.

Do high doses of quinolones decrease the emergence of antibacterial resistance? A systematic review of data from comparative clinical trials

OBJECTIVE

To evaluate whether the use of high doses of quinolones may reduce the development of antimicrobial resistance.

DATA SOURCES

Relevant studies were identified from PubMed and the Cochrane Central Register of Controlled Trials (until June 2006).

STUDY SELECTION AND DATA EXTRACTION

We performed a systematic review of the available data from comparative clinical studies reporting on the emergence of resistance when using different daily doses of quinolones.

DATA SYNTHESIS

Twelve studies reported comparative data regarding the emergence of antimicrobial resistance. Development of resistance occurred in patients of 5/12 studies included in the review, with no statistical difference between the compared arms.

CONCLUSIONS

Although data from laboratory studies are indicative of a benefit from using high daily doses of quinolones in order to minimize the emergence of antimicrobial resistance, the data from the reviewed trials are limited and can neither support nor reject this finding. However, it seems that if a true benefit exists this is rather small and regards mainly isolates with initially high minimum inhibitory concentrations. Further comparative clinical studies focusing on this issue are justified.

Serotypes, virulence factors, antibiotic sensitivity, beta-lactamase activity and plasmid analysis of Salmonella from children with diarrhea in Tripoli (Libya)

A total of 21 Salmonella strains isolated in Libya (16 from children with diarrhea and 5 from healthy controls) were serotyped and studied for their cell invasive ability, production of cytotoxin, antibiotic susceptibility, beta-lactamase activity and plasmid profiles. Eight different serotypes of Salmonella were identified: 6 S. saintpaul, 4 S. wien (1 from control), 2 S. newport, 2 S. muenchen (1 from control), 2 S. typhimurium (1 from control), 2 S. hadar (1 from control), 2 S. reading (1 from control), 1 S. kottbus. Twenty (95%) were positive in the invasiveness assay using HeLa cells, and all (100%) were negative for cytotoxin production in HT29 cells. More than 40% were resistant to ampicillin, cefalexin, cefamandole, cefoperazone, chloramphenicol, gentamicin, mezlocillin and trimethoprimsulphamethoxazole and 100% were susceptible to the new quinolones. Most (67%) of the strains harbored plasmids and 43% produced beta-lactamase. A strong association was observed between the presence of more than one plasmid, beta-lactamase activity, and multiple-resistance to antimicrobial agents and serotypes S. saintpaul and S. wien. Curing experiments with acridine orange showed that 2 plasmids (33 and 1.4 megadaltons) might be responsible for the resistance to chloramphenicol and gentamicin. The present study demonstrated that multiple-resistant salmonellae are widespread in Libya and the resistance is mainly plasmid mediated.

Campylobacter and fluoroquinolones: a bias data set?

There is no universally accepted standard method for the isolation of Campylobacter spp. and it is considered that currently available isolation media are not yet optimal for the recovery of Campylobacter spp. from a range of sample types. Almost all methods incorporate antibiotics into the isolation media to inhibit growth of other bacteria within the sample. It is established that the incorporation of such antibiotics into isolation media will inhibit the growth of some Campylobacter spp. as well as other bacteria. The results of the use of such suboptimal isolation methods are that the isolates which 'survive' the isolation procedure will be those which: (i) are able to 'out compete' the rest of the bacteria in the sample, i.e. they are able to grow faster; (ii) are resistant to the antibiotics used in the isolation media; and (iii) are randomly selected by the laboratory technician as being a 'typical'Campylobacter spp. It is clear that such a procedure is intrinsically biased and will mean that species resistant to the antibiotics used in the media will be isolated. This introduces real doubt that the bacteria isolated are truly representative of those initially found on the sample. It is also becoming clear that Campylobacter spp. are rather difficult to isolate as pure cultures and many are in fact mixtures of more than one strain. Again this introduces great uncertainty as to the prevalence and distribution of respective species from the different sample types. This is especially true when considering isolation of Campylobacter spp. causing disease in man as there is no certainty that the selected isolate is that which was responsible for disease. The incorporation of antibiotics into the isolation media not only introduces the issue of species bias but perhaps more importantly exposes the Campylobacter spp. to a cocktail of antibiotics thereby providing the potential for them to 'switch on' antibiotic resistance mechanisms. It might be argued that this has always been the case for isolation of Campylobacter spp., however, we know that the antibiotic cocktails used in media over the last 10 years have changed and indeed there was a time when the filtration protocol which didn't use antibiotics was more widely used. As most reports in the literature do not state what methods were used to isolate Campylobacter spp. it is not possible to quantify any relationship between antibiotics used in the isolation media and susceptibility data. An approved method for Campylobacter susceptibility testing was not available until May 2002, all data generated prior to this date will have been generated using non-standard methods. As tremendous variability in the reproducibility data for Campylobacter spp. was observed during the development of the standard agar dilution susceptibility method, data generated with disk diffusion and broth microdilution methods must be considered with caution. It has been shown that, compared with the conventional agar dilution method, the E-test tends to give rise to lower minimal inhibitory concentrations (MICs) for sensitive strains and higher MICs for resistant strains. There are no recommended antibiotic breakpoint concentrations for Campylobacter spp. A breakpoint is used to separate sensitive from resistant strains of bacteria and is thus crucial to any discussion of antibiotic resistance. This discussion is further complicated by introduction of the terms microbiological and clinical breakpoints. While a microbiological breakpoint can be a useful parameter with regard to identifying resistance factors it cannot on its own be used to predict whether that bacteria will respond to treatment from an appropriate antibiotic. Predicting clinical response is a function of the clinical breakpoint which considers the pharmacokinetic profile of the antimicrobial compound, i.e. the concentration of the antimicrobial compound in the body and the MIC. The National Committee for Clinical Laboratory Standards (NCCLS) uses microbiological, pharmacokinetic and clinical data to establish breakpoints, without c and clinical data to establish breakpoints, without such considerations it is not possible to consider what is truly clinically sensitive and resistant. There are no reported studies that have systematically determined appropriate breakpoints for Campylobacter, there are data however, which relate MICs to clinical outcome. It is without dispute that microbiological resistance in Campylobacter spp. occurs as a result of mutation in the gyrA gene with single point mutations most frequently causing a four- to eightfold shift in the MIC. What is also clear is that if a high enough concentration of antimicrobial relative to MIC of the infecting organism can be achieved not only will the parent organism be killed but also the 'resistant' mutant. Considering the above and the concentrations of ciprofloxacin achieved in the gastro-intestinal tract it is not surprising that clinical cure can be demonstrated for organisms with an MIC of 32 microg ml(-1).

Norfloxacin and Salmonella excretion in acute gastroenteritis--a 6-month follow-up study

In a controlled, randomized, double-blind study, 100 patients (66 women, 34 men; age 18-69 years) with acute salmonellosis were treated with norfloxacin (400 mg) or placebo tablets twice daily for 10 days to compare the effects on the excretion time of salmonella bacteria. In all patients salmonellae were detected in the stools before the start of treatment. The follow-up included 6 stool cultures after the start of treatment: day 3-4, day 12-14, and 4 times during 1-6 months. At 3-4 days there were 98% non-excretors in the norfloxacin group (46/47 patients) compared to 38% (17/45) in the placebo group (p < 0.001). The cumulative 6-month elimination rate in norfloxacin patients at 3-4 days was 72%, which was significantly (p = 0.0001) greater than the 31% in the placebo patients. However, there was no significant difference in the proportion of non-excretors or the elimination rate between the 2 groups at the following visits. Only one patient had an adverse event resulting in discontinuation of the treatment. We conclude that norfloxacin treatment for 10 days decreased the excretion of salmonella bacteria during the first week, but there was no difference in excretion rates 1-6 months after treatment initiation in the treatment versus placebo group.

The new quinolones in the treatment of diarrhoea and typhoid fever

Diarrhoea and typhoid fever are two important diseases in the developing world, particularly the Asian countries. The management of these conditions is becoming increasingly difficult in the face of emerging pathogen resistance. The new fluoroquinolones demonstrate good in vitro activity against the causative pathogens involved, including those that are multidrug resistant. These agents have been shown to be very effective in the treatment of diarrhoea and typhoid in clinical trials, achieving results equal to, or better than, standard drugs. Importantly, fluoroquinolones also considerably shorten the duration of illness, thereby offering rapid relief to the patient.

Effect of Storage Time and Temperature on Fecal Leukocytes and Occult Blood in the Evaluation of Travelers' Diarrhea

Both the presence of fecal leukocytes and occult blood in stool specimens of travelers with diarrhea have been used as indicators of colonic inflammation due to bacterial infection. This study was conducted to determine if storage temperature of stool specimens can affect the detection of leukocytes and occult blood. Sixteen specimens positive for occult blood and 23 specimens positive for leukocytes were divided into two aliquots. Each aliquot was held at 4 degreesC or 25 degreesC and reexamined daily for fecal leukocytes or occult blood. Four percent of the positive leukocytes specimens and 56% of the occult blood positive specimens were still positive on the fifth day when they were held at 4 degreesC. When the samples were held at 25 degreesC, leukocytes could not be detected after 3 days, but 19% were positive for occult blood on the fifth day. The results indicate that storage temperature of stool specimens was associated with a difference in detection rate.

Acute bacterial diarrhoea in the emergency room: therapeutic implications of stool culture results

Empiric treatment with ciprofloxacin and norfloxacin has been recommended recently for patients with acute diarrhoeal disease. In a retrospective 6-month study period the results of stool cultures from 209 patients with acute diarrhoea admitted to the emergency room were analysed. Seventy-eight cultures (37%) were positive for one or more bacteria. Shigella was the most commonly isolated pathogen (68%). Shigella sonnei comprised 72% and Shigella flexneri 19% of all the bacterial isolates. While no antimicrobial resistance to ciprofloxacin was found for both Shigella species, only 36 and 26% of the Shigella isolates were sensitive to ampicillin and trimethoprim-sulfamethoxazole (TMP-SMZ), respectively. These findings point out to the emergence of drug resistance to commonly used antimicrobial drugs. Shigella's high sensitivity to the newer quinolones should make this the treatment of choice for the very sick patient, although physicians should be cautioned to the fact that indiscriminate use of this drug could result in the emergence of resistance similar to that noted with ampicillin and TMP-SMZ.

Acute infectious diarrhea

Diarrhea continues to be a major cause of mortality and morbidity in third world countries as well as a major symptomatic complaint in the primary care setting in the United States. The etiologic pathogen depends on an exposure history to include recent travel to foreign countries, consuming fecally contaminated water or food, prior use of antibiotics, or homosexual behavior. A careful history from patients directed at attempting to identify particular risk factors may help in making a diagnosis. Not all patients require a diagnostic workup. A large number of patients may only require oral rehydration, careful observation over time with or without use of antimotility agents. In toxic appearing patients or patients with fever, however, bloody stools, abdominal pain or tenesmus, a selective diagnostic workup is indicated. Antimicrobial treatments are not always required, some pathogens clearly call for treatment while some have less clear indications and other pathogens are not responsive to antimicrobial agents at all. Finally, one needs to remember that the differential diagnosis of acute diarrhea includes many noninfectious origins.

Quinolones in the treatment of acute bacterial diarrhoeal diseases

Acute bacterial diarrhoea is still an important disease, especially in developing countries. Resistance to antibiotics among enteric pathogens is relatively common in many parts of the world. The quinolones are active in vitro against these organisms, and achieve high stool concentrations. Because of these features, quinolones have been used in the treatment of acute diarrhoeal diseases caused by various bacteria. They appear to be effective in the therapy of shigellosis and travellers' diarrhoea, as well as in the prevention of diarrhoeal disease in travellers. However, their role in the treatment of salmonella gastroenteritis has not been established yet.

Five versus three days of ofloxacin therapy for traveler's diarrhea: a placebo-controlled study

In this double-blind study with 232 patients, 300 mg of ofloxacin given orally twice daily for 5 or 3 days was compared with placebo for the treatment of acute diarrhea in U.S. students visiting Guadalajara, Mexico. The 3-day regimen of ofloxacin was found to be as effective as the 5-day regimen in producing a clinical and microbiologic cure. Clinical cures for patients who received ofloxacin for 5 days occurred in 59 of 66 (89%) subjects, whereas clinical cure occurred in 77 of 81 (95%) of those who received ofloxacin for 3 days and in 56 of 79 (71%) of those who took placebo (P = 0.0001). When the duration of diarrhea after therapy was begun was compared in subgroups, a significant (P less than 0.05) shortening of posttreatment illness occurred in comparison with that in the placebo group for the following groups: for 5 days of ofloxacin, cases of shigellosis (32 versus 98 h); for 3 days of ofloxacin, all cases (28 versus 56 h), cases of enterotoxigenic Escherichia coli diarrhea (26 versus 66 h), cases of shigellosis (24 versus 98 h), all cases of illnesses associated with a bacterial enteropathogen (28 versus 69 h), and cases of illnesses in which numerous leukocytes were found in stool by microscopy (22 versus 49 h). Microbiologic eradication rates were 75 of 78 (96%) for patients who received ofloxacin and 37 of 46 (80%) for patients who received placebo (P = 0.009). There was no significant difference in the number of adverse events reported by patients in either of the treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Emergence of fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli in subjects from Finland

The in vitro susceptibilities of 102 human campylobacter strains isolated between 1978 and 1980 and 100 strains isolated in 1990 to ciprofloxacin, norfloxacin, erythromycin, gentamicin, and doxycycline were examined. The biotypes and heat-stable serotypes of the strains as well as antimicrobial treatments and travel history of the campylobacter-positive patients were also studied. The results indicated that susceptibility to erythromycin, gentamicin, and doxycycline has remained the same during the past 10 years. No gentamicin-resistant strains were found. Resistance to erythromycin was 3% in both groups of strains. However, the number of norfloxacin-resistant strains increased from 4 to 11% in the follow-up period, and ciprofloxacin-resistant strains, which had not occurred 10 years ago, composed 9% of the strains isolated in 1990. Thus, the increase of fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli has been significant in Finland in the past 10 years.

Use of quinolones in the treatment of gastrointestinal infections

Bacterial enteropathogens are responsible for between 40% and 80% of diarrheal illness depending upon the age of the persons affected and geographic areas where illness occurs. Antibacterial agents will shorten the illness associated with enteric infection caused by enterotoxigenic Escherichia coli, Shigella spp. and Campylobacter jejuni. These drugs also are effective in the therapy of certain clinical conditions (presumably because they are due to the same agents) which are characterized by moderate to severe diarrhea with one or more of the following: high fever, dysentery (passage of bloody mucoid stools), or high leukocyte counts in stools. Antimicrobial agents are also effective in the therapy of travelers' diarrhea. The quinolone drugs have several advantages in the management of bacterial diarrhea where strains causing illness from nearly all regions of the world will show general susceptibility: high concentrations are achieved in the intestinal lumen following oral administration and resistance development is unusual. A quinolone probably represents the optimal agent for therapy of bacterial diarrhea in adults in areas where trimethoprim-resistant enteric pathogens are common.

Infectious enteritis. A collective review

Enteric infections are a major cause of diarrhea in the United States. Pathogens can cause diarrhea by elaboration of toxins that affect the intestinal mucosa or by direct invasion of the intestinal wall. Clinical evaluation can provide important clues to aid in establishing a correct diagnosis in most patients with infectious enteritis. Appropriate cultures are necessary to confirm the diagnosis in most cases. Most types of infectious enteritis are self-limiting, but some pathogens can cause serious disease, requiring accurate diagnosis and suitable antibiotic therapy. Appropriate precautions are mandatory to prevent the spread of infectious diarrhea from occurring in the hospital environment. Dietary restrictions and appropriate hygiene should be observed during travel to foreign countries to reduce the chance of acquiring infectious enteritis.

Quinolones and the gastrointestinal tract

A number of studies have evaluated the efficacy of the new fluoroquinolones for therapy of bacterial enteric diseases and for prevention of gram-negative sepsis in granulocytopenic patients. The success of the quinolones in these settings is related to several special features of these agents, including their spectrum of activity and high fecal levels, which are in turn reflected in their effect on the gastrointestinal flora. Other factors that are important, particularly for invasive disease such as typhoid fever and shigellosis, include good intracellular and bowel wall penetration, and lymph node and systemic drug concentrations many times higher than the MICs of the causative organisms. This article reviews the factors that contribute to the changes in fecal flora, and the results of clinical studies in patients with diarrhea, granulocytopenic patients, and patients with selected other infections of, or related to, the gastrointestinal tract.

Fluoroquinolone antimicrobial agents

The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous system toxicities occurring most commonly, but only rarely necessitating discontinuance of therapy. In 17 of 18 prospective, randomized, double-blind comparisons with another agent or placebo, fluoroquinolones were tolerated as well as or better than the comparison regimen. Bacterial resistance has been uncommonly documented but occurs, most notably with P. aeruginosa and Staphylococcus aureus and occasionally other species for which the therapeutic ratio is less favorable. Fluoroquinolones offer an efficacious, well-tolerated, and cost-effective alternative to parenteral therapies of selected infections.

Comparison of single-dose treatment with norfloxacin and standard 5-day treatment with trimethoprim-sulfamethoxazole for acute shigellosis in adults

Shigellae have been shown to be highly susceptible to new quinolone agents, with average MICs for 90% of isolates of less than 0.1 microgram/ml. Because these agents also reach high concentrations in the stool after a single dose, the effectiveness of a single 800-mg dose of norfloxacin and of 5-day treatment with trimethoprim-sulfamethoxazole (TMP-SMX) were compared in a randomized trial. Patients with clinical dysentery received one of these treatment regimens, and clinical data and follow-up culture results were analyzed for patients whose stool culture on presentation grew shigellae. When 55 patients with shigellosis (26 treated with TMP-SMX, 29 treated with norfloxacin) whose bacterial isolates were susceptible to the antibiotic given were compared by treatment group, no significant differences were seen in days of illness (mean, 2.5 +/- 0.65 days with TMP-SMX and 2.0 +/- 0.47 days with norfloxacin; P = 0.200) or number of unformed stools after starting treatment (mean, 9.7 +/- 2.37 stools with TMP-SMX and 7.6 +/- 3.19 stools with norfloxacin; P = 0.312). Resistance in vitro to TMP-SMX was seen in 15% of Shigella isolates, whereas none was resistant to norfloxacin. Bacteriologic failure was found in 1 patient among 24 receiving TMP-SMX and in none of 25 patients receiving norfloxacin. One single dose of norfloxacin was as effective as 5 days of treatment with TMP-SMX in these adults with shigellosis.

Postoperative prophylaxis with norfloxacin in patients requiring bladder catheters

The effect of once daily doses of 200 mg oral norfloxacin on the occurrence of catheter-associated bacteriuria (greater than 1000 CFU/ml) and pyuria was studied in 105 post-operative gynaecologic patients. Norfloxacin was given from the second day after surgery until catheter removal. Bacteriuria developed in 32 of 51 (63%) control patients compared to 8 of 54 (15%) patients receiving norfloxacin (p less than 0.001). Pyuria was present in 22 of 51 (43%) control subjects versus only 3 of 54 (5%) patients treated with norfloxacin (p less than 0.001). Bacteria isolated from control patients comprised species of Enterobacteriaceae (40%), Staphylococcus (35%), and Streptococcus (17%); seven isolates were resistant to multiple antibiotics reflecting their nosocomial origin. In contrast, strains isolated from norfloxacin-treated patients comprised non-fermenting gram-negative rods (79%, usually Alcaligenes or Acinetobacter spp.) and faecal streptococci (12%). It is concluded that once daily doses of 200 mg oral norfloxacin are effective in reducing the rate of catheter-associated bacteriuria and pyuria following reconstructive gynaecologic surgery.