Safety and efficacy of ciprofloxacin in paediatric patients--review

Safety of Quinolones in Children: A Systematic Review and Meta-Analysis

BACKGROUND

The results of animal experiments show that quinolone antibacterial drugs may permanently damage the soft tissues of the weight-bearing joints of young animals. Out of safety concerns, using quinolones in children has always been controversial.

OBJECTIVE

The aim of this study was to assess the risk of using quinolones in children and provide evidence for clinicians to support decision making.

DATA SOURCES

The MEDLINE (Ovid), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), International Pharmaceutical Abstracts (Ovid), CINAHL, CNKI, VIP, and WanFang Data databases were searched from inception to 8 September 2021.

STUDY SELECTION

All types of studies that reported the safety data of quinolones in children, including clinical trials and observational studies.

DATA EXTRACTION

Data extraction and cross-checking were completed by two independent reviewers using a pilot-tested standardized data extraction form.

RESULTS

The overall incidence rate of adverse drug events (ADEs) in children using systemic quinolones was 5.39% and the most common ADEs were gastrointestinal reactions (incidence rate, 2.02%). Quinolone-induced musculoskeletal ADEs in children were uncommon (0.76%). Meta-analysis results showed that the risk of musculoskeletal ADEs in children using quinolones was higher than children in the control group (51 studies; rate ratio [RR] 2.03, 95% confidence interval [CI] 1.82-2.26; p < 0.001; I² = 18.6%; moderate-quality evidence). However, the subgroup analysis results showed that differences might only be observed in children who were followed up for 2 months to 1 year (2-6 months: RR 2.56, 95% CI 2.26-2.89; 7 months to 1 year: RR 1.35, 95% CI 0.98-1.86). Moreover, children (adolescents) aged between 13 and 18 years might be sensitive to the musculoskeletal toxicity of quinolones (RR 2.69, 95% CI 2.37-3.05; moderate-quality evidence) and the risk of levofloxacin-induced musculoskeletal ADEs might be higher (RR 1.33, 95% CI 1.00-1.77; low-quality evidence).

CONCLUSIONS

Although the existing evidence shows that quinolone-induced musculoskeletal ADEs seem to be only short-term and reversible, and no serious skeletal and muscular system damage cases have been reported in children, quinolones should be avoided unless necessary in children because the incidence rate of quinolone-related ADEs is not low and they are broad-spectrum antibiotics that will induce the emergence of resistant strains if used frequently.

Biomimetic Aspects of Restorative Dentistry Biomaterials

Biomimetic has emerged as a multi-disciplinary science in several biomedical subjects in recent decades, including biomaterials and dentistry. In restorative dentistry, biomimetic approaches have been applied for a range of applications, such as restoring tooth defects using bioinspired peptides to achieve remineralization, bioactive and biomimetic biomaterials, and tissue engineering for regeneration. Advancements in the modern adhesive restorative materials, understanding of biomaterial–tissue interaction at the nano and microscale further enhanced the restorative materials’ properties (such as color, morphology, and strength) to mimic natural teeth. In addition, the tissue-engineering approaches resulted in regeneration of lost or damaged dental tissues mimicking their natural counterpart. The aim of the present article is to review various biomimetic approaches used to replace lost or damaged dental tissues using restorative biomaterials and tissue-engineering techniques. In addition, tooth structure, and various biomimetic properties of dental restorative materials and tissue-engineering scaffold materials, are discussed.

Epidemiology, Clinical Presentation, Laboratory Diagnosis, Antimicrobial Resistance, and Antimicrobial Management of Invasive Salmonella Infections

Salmonella enterica infections are common causes of bloodstream infection in low-resource areas, where they may be difficult to distinguish from other febrile illnesses and may be associated with a high case fatality ratio. Microbiologic culture of blood or bone marrow remains the mainstay of laboratory diagnosis. Antimicrobial resistance has emerged in Salmonella enterica, initially to the traditional first-line drugs chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole. Decreased fluoroquinolone susceptibility and then fluoroquinolone resistance have developed in association with chromosomal mutations in the quinolone resistance-determining region of genes encoding DNA gyrase and topoisomerase IV and also by plasmid-mediated resistance mechanisms. Resistance to extended-spectrum cephalosporins has occurred more often in nontyphoidal than in typhoidal Salmonella strains. Azithromycin is effective for the management of uncomplicated typhoid fever and may serve as an alternative oral drug in areas where fluoroquinolone resistance is common. In 2013, CLSI lowered the ciprofloxacin susceptibility breakpoints to account for accumulating clinical, microbiologic, and pharmacokinetic-pharmacodynamic data suggesting that revision was needed for contemporary invasive Salmonella infections. Newly established CLSI guidelines for azithromycin and Salmonella enterica serovar Typhi were published in CLSI document M100 in 2015.

Prophylaxis and treatment of anthrax in pregnant women

OBJECTIVE

To review the safety and pharmacokinetics of antimicrobials recommended for anthrax postexposure prophylaxis and treatment in pregnant women.

DATA SOURCES

Articles were identified in the PubMed database from inception through December 2012 by searching the keywords (["pregnancy]" and [generic antibiotic drug name]). Additionally, we searched clinicaltrials.gov and conducted hand searches of references from REPROTOX, TERIS, review articles, and Briggs' Drugs in Pregnancy and Lactation.

METHODS OF STUDY SELECTION

Articles included in the review contain primary data related to the safety and pharmacokinetics among pregnant women of 14 antimicrobials recommended for anthrax postexposure prophylaxis and treatment (amoxicillin, ampicillin, chloramphenicol, clindamycin, ciprofloxacin, doripenem, doxycycline, levofloxacin, linezolid, meropenem, moxifloxacin, penicillin, rifampin, and vancomycin).

TABULATION, INTEGRATION, AND RESULTS

The PubMed search identified 3,850 articles for review. Reference hand searching yielded nine additional articles. In total, 112 articles met the inclusion criteria.

CONCLUSIONS

Overall, safety and pharmacokinetic information is limited for these antimicrobials. Although small increases in risks for certain anomalies have been observed with some antimicrobials recommended for prophylaxis and treatment of anthrax, the absolute risk of these antimicrobials appears low. Given the high morbidity and mortality associated with anthrax, antimicrobials should be dosed appropriately to ensure that antibiotic levels can be achieved and sustained. Dosing adjustments may be necessary for the β-lactam antimicrobials and the fluoroquinolones to achieve therapeutic levels in pregnant women. Data indicate that the β-lactam antimicrobials, the fluoroquinolones, and, to a lesser extent, clindamycin enter the fetal compartment, an important consideration in the treatment of anthrax, because these antimicrobials may provide additional fetal benefit in the second and third trimesters of pregnancy.

Paediatric use of second-line anti-tuberculosis agents: a review

Childhood multidrug-resistant tuberculosis (MDR-TB) is an emerging global epidemic. With the imminent roll-out of rapid molecular diagnostic tests, more children are likely to be identified and require treatment. As MDR-TB is resistant to the most effective first-line drugs, clinicians will have to rely on second-line medications which are less effective and often associated with more pronounced adverse effects than first-line therapy. Despite the fact that most of these agents were discovered many years ago, robust information is lacking regarding their pharmacokinetic and pharmacodynamic properties, adverse effects and drug interactions, especially in children. Children differ from adults in the way that drugs are administered, the manner in which they are metabolised and in the adverse effects experienced. The interaction of these drugs with human immunodeficiency virus infection and antiretroviral therapy is also poorly documented. This article reviews the available second-line drugs currently used in the treatment of MDR-TB in children and discusses medication properties and adverse effects while potential interactions with antiretroviral therapy are explored.

Ciprofloxacin use in neonates: a systematic review of the literature

BACKGROUND

ciprofloxacin has no marketing authorization for use in neonates worldwide but it is prescribed for the treatment of neonatal life-threatening infections, mainly in developing countries and in Europe. Given the concerns about its toxicity in this population and the necessity for its use in specific clinical situations, we conducted a systematic review of the use of ciprofloxacin in neonates.

METHODS

we performed a systematic search of PubMed, Embase, and the Cochrane Database of Systematic Reviews and bibliographies of relevant articles. We included all studies, regardless of design, that reported efficacy, safety, and pharmacokinetics of ciprofloxacin for the treatment of any neonatal infectious condition. We excluded letters, editorials, preliminary reports, and abstracts.

RESULTS

observational cohort studies, case reports, and descriptions of patient series account for all literature reviewed. Ciprofloxacin was administrated in neonates as a salvage therapy for sepsis due to multidrug-resistant strains or with signs of clinical deterioration under first-line antibiotic treatment. Initial administration was always intravenous with variable dosing schedule. Clinical response to treatment was estimated at 64% and 91% in 2 cohort studies, with a median of 83% in case series. Of the 14 case reports, 12 yielded positive clinical outcomes. No serious adverse events, particularly joint toxicity, were observed, although evaluation was predominantly clinical and follow-up limited to few months after the end of treatment.

CONCLUSIONS

the current literature provides some information to support the use of ciprofloxacin in neonates. Additional high quality studies should be undertaken to provide reliable data on pharmacokinetics, efficacy, and long-term safety.

Ciprofloxacin treatment in preterm neonates in Bangladesh: lack of effects on growth and development

BACKGROUND

Quinolone-induced arthropathic toxicity in weight-bearing joints observed in juvenile animals during preclinical testing has largely restricted the routine use of ciprofloxacin in the pediatric age group. As histopathologic, radiologic and magnetic resonance imaging monitoring evidence has gathered supporting the safety of fluoroquinolones in children, many pediatricians have started to prescribe quinolones to some patients on a compassionate basis.

OBJECTIVE

The objective of this study was to ascertain the safety of ciprofloxacin in preterm neonates <33 weeks gestational age treated at Dhaka Shishu (Children) Hospital in Bangladesh.

METHODS

Long-term follow up was done to monitor the growth and development of preterm infants who were administered intravenous ciprofloxacin in the neonatal period. Ciprofloxacin was used only as a life-saving therapy in cases of sepsis produced by bacterial agents resistant to other antibiotics. Another group of preterm neonates with septicemia who were not exposed to ciprofloxacin, but effectively treated with other antibiotics and followed up, were matched with cases for gender, gestational age and birth weight and included as a comparison group. Forty-eight patients in the ciprofloxacin group and 66 patients in the comparison group were followed up for a mean of 24.7 +/- 18.5 months and 21.6 +/- 18.8 months, respectively.

RESULTS

No osteoarticular problems or joint deformities were observed in the ciprofloxacin group during treatment or follow up. No differences in growth and development between the groups were found.

CONCLUSIONS

Ciprofloxacin is a safe therapeutic option for newborns with sepsis produced by multiply resistant organisms.

Staphylococcal skin infections in children: rational drug therapy recommendations

Staphylococcus aureus remains one of the most common and troublesome of bacteria causing disease in humans, despite the development of effective antibacterials and improvement in hygiene. The organism is responsible for over 70% of all skin and soft tissue infections in children and accounts for up to one-fifth of all visits to pediatric clinics. Skin and soft tissue infections that are predominantly caused by S. aureus include bullous and non-bullous impetigo, folliculitis, furunculosis, carbunculosis, cellulitis, surgical and traumatic wound infections, mastitis, and neonatal omphalitis. Other skin and soft tissue infections may also be caused by S. aureus but are often polymicrobial in origin and require special consideration. These include burns, decubitus ulcers (particularly in the perianal region), puncture wounds of the foot, as well as human and mammalian bites. Treatment of staphylococcal skin infections varies from topical antiseptics to prolonged intravenous antibacterials, depending on severity of the lesions and the health of the child. The treatment of choice for oral antibacterials remains the penicillinase-resistant penicillins such as flucloxacillin. Cefalexin and erythromycin are suitable cost-effective alternatives with broader cover, although care must be taken with the use of macrolides because of development of resistance to multiple families of antibacterials, particularly the lincosamides. Other cephalosporins such as cefadroxil and cefprozil are also effective, can be given once daily and have a better tolerability profile -- while azithromycin has a further advantage of a 3-day course. However, all of these agents are more expensive. Although the antibacterials have been given for 10 days in most clinical trials, there is no evidence that this duration is more effective than a 7-day course. In children requiring intravenous therapy, ceftriaxone has a major advantage over other antibacterials such as sulbactam/ampicillin and cefuroxime in that it can be given once daily and may, therefore, be suitable for outpatient treatment of moderate-to-severe skin infections. Newer-generation cephalosporins and loracarbef are also effective and have a broader spectrum of activity, but do not offer any added benefit and are significantly more expensive. Skin and soft tissue infections due to methicillin-resistant S. aureus (MRSA) are still relatively uncommon in children. Well children with community-acquired MRSA infections can be treated with clindamycin or trimethoprim-sulfamethoxazole (cotrimoxazole), but must be observed closely for potentially severe adverse effects. In severe infections, vancomycin remains the treatment of choice, while intravenous teicoplanin and clindamycin are suitable alternatives. Linezolid and quinupristin/dalfopristin are currently showing great promise for the treatment of multi-resistant Gram-positive infections. While the choice of antibacterial is important, supportive management, including removal of any infected foreign bodies, surgical drainage of walled-off lesions, and regular wound cleaning, play a vital role in ensuring cure.

Systemic quinolone antibiotics in children: a review of the use and safety

Historically, healthcare providers have reluctantly used systemic quinolone antibiotics to treat infections in children when they have been used at all. Concerns regarding the oral or parenteral use of quinolones in children rose from research observations demonstrating cartilage and joint toxicity in juvenile animal models following the administration of this class of antibiotics to immature animals. A voluntary moratorium on the use of quinolone and fluoroquinolone antibiotics in children resulted in restricting their use to treat in infections in specific settings such as immunocompromised states due to chemotherapy, pseudomonas infections in cystic fibrosis patients, complicated urinary tract infections, and quinolone sensitive infectious disease where parenteral antibiotic administration is not available and quinolones were the only effective therapy. This article aims to review retrospective and prospective safety and efficacy data to provide a comprehensive summary of the systemic use of this class of antibiotics in children.

Population pharmacokinetics of ciprofloxacin in pediatric and adolescent patients with acute infections

The aim of the present study was to characterize the population pharmacokinetics of ciprofloxacin in patients with and without cystic fibrosis ranging in age from 1 day to 24 years and to propose a limited sampling strategy to estimate individual pharmacokinetic parameters. Patients were divided into four groups according to the treatment schedule. They received ciprofloxacin by intravenous infusion (30 min) or by the oral route. The number of samples collected from each patient ranged from 1 to 12. The population parameters were computed for an initial group of 37 patients. The data were analyzed by nonlinear mixed-effect modeling by use of a two-compartment structural model. The interindividual variability in clearance (CL) was partially explained by a dependence on age and the patient's clinical status. In addition, a significant relationship was found between weight and the initial volume of distribution. Eighteen additional patients were used for model validation and evaluation of limited sampling strategies. When ciprofloxacin was administered intravenously, sampling at a single point (12 h after the start of infusion) allowed the precise and accurate estimation of CL and the elimination half-life, as well as the ciprofloxacin concentration at the end of the infusion. It should be noted that to take into account the presence of a lag time after oral administration, a schedule based on two sampling times of 1 and 12 h is needed. The results of this study combine relationships between ciprofloxacin pharmacokinetic parameters and patient covariates that may be useful for dose adjustment and a convenient sampling procedure that can be used for further studies.

Outpatient management of febrile neutropenia in children with cancer

The objectives of this article are to review the studies that have examined the safety and feasibility of outpatient management for children with febrile neutropenia, and to provide recommendations as to which patient populations and treatment strategies are most appropriate for this approach. The outpatient strategies have included either complete outpatient management or employment of early discharge, with the latter methodology predominating in most published studies. Common criteria relied upon to identify children with febrile neutropenia at low risk of serious infections included evidence of hematopoietic recovery and/or an absolute monocyte count >/=100/mm(3), and the absence of both comorbidity and culture positivity. A wide variety of different antibacterial regimens have been employed, with some trials investigating either early discontinuation of treatment or conversion to an oral administration strategy. Trials performed to date among this low risk population indicate a very low rate of readmission and/or complications. Some studies have also estimated substantial overall cost savings with this approach. However, many of these trials are significantly underpowered to detect the low rate of serious complications in the pediatric population with febrile neutropenia. At present, the available evidence indicates that a carefully chosen subpopulation of children with febrile neutropenia can be safely managed on an outpatient basis. Regardless of setting, current clinical guidelines for febrile neutropenia management indicate that all children with febrile neutropenia should be managed with appropriate antibacterial therapy until resolution of febrile neutropenia. Treatment with either an oral antibacterial regimen as initial therapy, or early discontinuation of antibacterial therapy in the outpatient setting should remain investigational at the present time.

Safety profile of quinolone antibiotics in the pediatric population

Fluoroquinolone-induced joint/cartilage toxicity has been observed in juvenile animal studies and is species- and dose-specific with canines exhibiting the highest rate of arthralgias. These early observations led to the contraindication of fluoroquinolones in the pediatric population. Despite these recommendations fluoroquinolones continue to be prescribed for select children with difficult-to-treat infections for whom the benefit of quinolone therapy may outweigh the risk of cartilage toxicity. A review of retrospective and prospective safety data of ciprofloxacin-treated children showed that the rates of arthralgia and quinolone-induced cartilage toxicity were low. Episodes of arthralgia were mostly reversible based on published surveillance data in children. Recent data from Bayer's ciprofloxacin clinical trials database found that the incidence of arthralgia in children did not differ between the ciprofloxacin and nonquinolone antimicrobial control groups. The role of fluoroquinolones in the treatment of certain serious infections in children does not appear to be compromised by safety concerns when used appropriately.

Fluoroquinolone safety in pediatric patients: a prospective, multicenter, comparative cohort study in France

OBJECTIVE

To evaluate the safety of fluoroquinolones (FQ) in comparison with other antibiotics in pediatric patients.

METHODS

A multicenter, observational, comparative cohort study was conducted between 1998 and 2000 in French pediatric departments. Patients who were receiving systemic FQ were included and matched to control patients who were receiving other antibiotics. Antibiotic-associated potential adverse events (PAEs) were recorded prospectively in both groups, and their rates were compared using univariate and multivariate analyses.

RESULTS

Patients were recruited from 73 centers: 276 patients were exposed to FQ, and 249 composed the control group. Among patients who were exposed to FQ, 23% were younger than 2 years, 33% had cystic fibrosis, and PAEs occurred in 52 patients, leading to withdrawal for 11. The odds ratio for PAE in the FQ group was 3.7 (95% confidence interval: 1.9-7.5) and was not significantly modified after adjustment for potential confounders. Musculoskeletal PAEs also occurred more frequently in the FQ group (3.8%) than in controls (0.4%); they were recorded in 10 patients who were receiving standard FQ doses and were of moderate intensity and transient.

CONCLUSION

The rates of PAEs and musculoskeletal PAEs were higher for the FQ group than the control group. This observation supports the American Academy of Pediatrics statement restricting off-label FQ use in pediatric patients to second-line treatment in a limited number of situations.

Safety of fluoroquinolones in paediatrics

In the last few years, there has been increasing pressure to use fluoroquinolones in paediatric patients, since these antibiotics offer the advantage of an oral treatment regimen on an out-patient basis. However, even although this class of antibiotics generally remains well-tolerated, the restriction of fluoroquinolone use in children on a compassionate basis, which derives from their potential to cause cartilage toxicity, limits the safety data in this population and suggests a cautious use. This review reports the data of the literature on the safety of fluoroquinolones in different districts, focusing on the side effects in children and drug interactions. Moreover, data available in the literature with regards to side effects in children are reported, with particular attention to their potential in arthropathy.

A critical review of the fluoroquinolones: focus on respiratory infections

The new fluoroquinolones (clinafloxacin, gatifloxacin, gemifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin) offer excellent activity against Gram-negative bacilli and improved Gram-positive activity (e.g. against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Ciprofloxacin still maintains the best in vitro activity against Pseudomonas aeruginosa. Clinafloxacin, gatifloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (e.g. Bacteroides fragilis) versus ciprofloxacin. All of the new fluoroquinolones display excellent bioavailability and have longer serum half-lives than ciprofloxacin allowing for once daily dose administration. Clinical trials comparing the new fluoroquinolones to each other or to standard therapy have demonstrated good efficacy in a variety of community-acquired respiratory infections (e.g. pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis). Limited data suggest that the new fluoroquinolones as a class may lead to better outcomes in community-acquired pneumonia and acute exacerbations of chronic bronchitis versus comparators. Several of these agents have either been withdrawn from the market, had their use severely restricted because of adverse effects (clinafloxacin because of phototoxicity and hypoglycaemia; grepafloxacin because of prolongation of the QTc and resultant torsades de pointes; sparfloxacin because of phototoxicity; and trovafloxacin because of hepatotoxicity), or were discontinued during developmental phases. The remaining fluoroquinolones such as gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin have adverse effect profiles similar to ciprofloxacin. Extensive post-marketing safety surveillance data (as are available with ciprofloxacin and levofloxacin) are required for all new fluoroquinolones before safety can be definitively established. Drug interactions are limited; however, all fluoroquinolones interact with metal ion containing drugs (eg. antacids). The new fluoroquinolones (gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin) offer several advantages over ciprofloxacin and are emerging as important therapeutic agents in the treatment of community-acquired respiratory infections. Their broad spectrum of activity which includes respiratory pathogens such as penicillin and macrolide resistant S. pneumoniae, favourable pharmacokinetic parameters, good bacteriological and clinical efficacy will lead to growing use of these agents in the treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis. These agents may result in cost savings especially in situations where, because of their potent broad-spectrum activity and excellent bioavailability, they may be used orally in place of intravenous antibacterials. Prudent use of the new fluoroquinolones will be required to minimise the development of resistance to these agents.

The safety profile of the fluoroquinolones

BACKGROUND

Premarketing trials showed the fluoroquinolone agents to have a favorable side-effect profile, with treatment-related adverse events comprising gastrointestinal, central nervous system, and dermatologic effects that were generally mild and reversible on cessation of treatment. However, postmarketing surveillance studies have identified severe adverse events, including severe anaphylaxis, QTc-interval prolongation, and potential cardiotoxicity, associated with 3 quinolone agents that either resulted in the removal of the agent from the market (temafloxacin and grepafloxacin) or significantly restricted its use due to substantial mortality and morbidity associated with liver toxicity (trovafloxacin). To date, there have been no such significant adverse events associated with the older fluoroquinolone agents, including ciprofloxacin, ofloxacin, norfloxacin, and levofloxacin. However, there are fewer data from postmarketing surveillance studies on the most recently approved agents, such as moxifloxacin and gatifloxacin, or agents awaiting approval, such as gemifloxacin.

OBJECTIVE

This paper examines safety data from the premarketing trials and postmarketing surveillance studies of fluoroquinolones available in the United States.

METHODS

A MEDLINE search was performed to identify all English-language studies published since 1980 concerning the safety profiles of the fluoroquinolones.

CONCLUSIONS

The fluoroquinolone antibacterial agents offer broad-spectrum therapy in patients with a variety of infections. Given similar spectra of activity, the choice between quinolones may be based on differences in efficacy and safety or tolerability profiles. Most drug reactions involving these agents are minor and reversible on discontinuing treatment, but adverse effects can be associated with significant mortality and morbidity, as was seen in the case of trovafloxacin and temafloxacin.

Ciprofloxacin in children: is arthropathy a limitation?

Two hundred and nineteen children treated with Ciprofloxacin were observed for drug related adverse reactions (ADR). ADR was observed in 35/219 (15.98%) children, arthropathy in 2/219 (0.9%) children only. All the ADR were reversible even on continuation of therapy except one child with arthropathy and no permanent sequele or death occurred as a drug related ADR.

Clinical use of fluoroquinolones in children

OBJECTIVE

To review the pharmacokinetics, efficacy, and safety of fluoroquinolones in children.

DATA SOURCES

A MEDLINE search (January 1966-March 1998) was conducted for relevant literature.

STUDY SELECTION AND DATA EXTRACTION

Data from compassionate use and published studies were reviewed for the assessment of pharmacokinetics, efficacy, and safety of fluoroquinolones in children.

DATA SYNTHESIS

Fluoroquinolones have a broad spectrum coverage of gram-positive and gram-negative bacteria, including Pseudomonas aeruginosa and intracellular organisms. Fluoroquinolones are well absorbed from the gastrointestinal tract, have excellent tissue penetration, low protein binding, and long elimination half-lives. These antibiotics are effective in treating various infections and are well tolerated in adults. However, the use of fluoroquinolones in children has been restricted due to potential cartilage damage that occurred in research with immature animals. Fluoroquinolones have been used in children on a compassionate basis. Ciprofloxacin is the most frequently used fluoroquinolone in children, most often in the treatment of pulmonary infection in cystic fibrosis as well as salmonellosis and shigellosis. Other uses include chronic suppurative otitis media, meningitis, septicemia, and urinary tract infection. Safety data of fluoroquinolones in children appear to be similar to those in adults. Fluoroquinolones are associated with tendinitis and reversible arthralgia in adults and children. However, direct association between fluoroquinolones and arthropathy remains uncertain.

CONCLUSIONS

Fluoroquinolones have been found to be effective in treating certain infections in children. Additional research is needed to define the optimal dosage regimens in pediatric patients. Although fluoroquinolones appear to be well tolerated, further investigations are needed to determine the risk of arthropathy in children. However, their use in children should not be withheld when the benefits outweigh the risks.

The comparative arthropathy of fluoroquinolones in dogs

1. Fluoroquinolone antibiotics are generally only prescribed to paediatric patients on compassionate grounds. This is because they are known to cause lesions in the cartilage of the major diarthroidal joints in immature experimental animals. As dogs are considered to be the most sensitive species, a series of studies was performed to compare the potential for grepafloxacin (a new fluoroquinolone) to cause arthropathy to that of ofloxacin and ciprofloxacin in juvenile (3 month old) beagles. 2. Grepafloxacin was administered once daily to male juvenile dogs at dosages of up to 100 mg/kg/day (intravenously), 60 mg/kg/day (orally) or 30 mg/kg/day (subcutaneously) for 1 week. Blister formation was observed on the surface of the joints in one of the three animals treated with grepafloxacin intravenously at 100 mg/kg/day. No abnormalities were observed at lower dosages or when grepafloxacin was administered orally or subcutaneously, regardless of dose. In animals treated with ofloxacin or ciprofloxacin at dosages of 10-30 mg/kg/day, blister formation or erosion was observed on the surface of joints regardless of dose or route of administration. 3. Histopathological examination of the joint surfaces of affected animals revealed the loss of cartilaginous matrix and chondrocytes, cavitation within the intermediate zone of cartilage accompanied by cartilage fibrillation or chondrocyte clustering, or loss of the surface layer which covers the cavitation (or loss of outer wall of the cavity). These findings were not present in the absence of grossly observed lesions. 4. Absorption following oral administration of grepafloxacin was low. Examination of plasma concentrations of drug following intravenous administration showed that joint toxicity was seen with ofloxacin and ciprofloxacin at maximum concentrations as low as 3.80 and 4.24 mg/l, respectively, while plasma levels of grepafloxacin of up to 11.95 mg/l failed to cause such lesions. When the concentration of grepafloxacin was 18.69 mg/l a single joint lesion was seen. Following subcutaneous administration of grepafloxacin, systemic exposure (area under the curve) of approximately 1.5 times that seen in man was not associated with joint lesions. However, lesions were noted for ofloxacin and ciprofloxacin treated animals at exposures equal to or below those seen in man. Therefore grepafloxacin appeared to have a relatively low potential for joint toxicity; this was not due to lack of penetration into the synovial fluid.

The new fluoroquinolones: A critical review

OBJECTIVE

This paper reviews the literature available on the new fluoroquinolones - clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sparfloxacin and trovafloxacin - to compare these agents with each other and contrast them with ciprofloxacin, an older fluoroquinolone.

DATA SELECTION

Published papers used were obtained by searching MEDLINE for articles published between 1994 and 1998, inclusive. References of published papers were also obtained and reviewed. Abstracts from scientific proceedings were reviewed.

DATA EXTRACTION

Due to the limited data available on several of the agents, criteria for study inclusion in the in vitro, pharmacokinetics and in vivo sections were not restrictive.

DATA SYNTHESIS

The new fluoroquinolones offer excellent Gram-negative bacillary activity and improved Gram-positive activity (eg, against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Clinafloxacin, gatifloxacin, moxifloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (eg, Bacteriodes fragilis). All of the new fluoroquinolones have a longer serum half-life than ciprofloxacin (allowing for once daily dosing), and several are eliminated predominantly by nonrenal means. No clinical trials are available comparing the new fluoroquinolones with each other. Clinical trials comparing the new fluoroquinolones with standard therapy have demonstrated good efficacy in a variety of infections. Their adverse effect profile is similar to that of ciprofloxacin. Clinafloxacin and sparfloxacin cause a high incidence of phototoxicity (1.5% to 14% and 2% to 11.7%, respectively), grepafloxacin causes a high incidence of taste perversion (9% to 17%) and trovafloxacin causes a high incidence of dizziness (11%). They all interact with metal ion-containing drugs (eg, antacids), and clinafloxacin and grepafloxacin interact with theophylline. The new fluoroquinolones are expensive; however, their use may result in savings in situations where, because of their potent and broad spectrum of activity, they can be used orally in place of intravenous antibiotics.

CONCLUSIONS

The new fluoroquinolones offer advantages over ciprofloxacin in terms of improved in vitro activity and pharmacokinetics. Whether these advantages translate into improved clinical outcomes is presently unknown. The new fluoroquinolones have the potential to emerge as important therapeutic agents in the treatment of respiratory tract and genitourinary tract infections.

A comparative study of the repeat dose toxicity of grepafloxacin and a number of other fluoroquinolones in rats

Grepafloxacin is a new oral fluoroquinolone with potent activity against community acquired respiratory pathogens, including Streptococcuspneumoniae, and pharmacokinetic properties which allow once daily dosing. As part of its safety evaluation a study of 4 weeks duration was performed to compare the toxicity of grepafloxacin with that of a number of commercially available quinolones in the rat. Groups of eight male Sprague-Dawley rats received either control material or grepafloxacin, enoxacin, lomefloxacin, ofloxacin or ciprofloxacin at an oral dosage of 300 mg/kg/day for 4 consecutive weeks. Effects related to the antibacterial activity of the drugs were seen as increased caecal weight, decreased urinary excretion of sodium, increased water consumption, decreased urine volume, increased urine osmolality, soft stools and suppressed body weight gain. It is well documented that fluoroquinolones can cause lesions in the cartilage of the major diarthrodial joints, and blister formation or erosion on the joint surface was observed in all quinolone-treated groups other than the grepafloxacin group. Some quinolones, have been found to cause crystalluria, which is often associated with secondary nephropathy in laboratory animals due to the poor solubility of quinolones under the alkaline conditions of the urine. In the present study, needle-like crystals in the urinary sediment were observed in enoxacin and ciprofloxacin treated groups only. In conclusion, grepafloxacin was well tolerated and showed a low potential for joint toxicity and crystalluria compared to other quinolones.

Trovafloxacin: a new fluoroquinolone

OBJECTIVE

To review the pharmacology, antimicrobial activity, pharmacokinetics, clinical efficacy, and safety of trovafloxacin.

DATA SOURCES

A MEDLINE search (January 1966-April 1998) was conducted for relevant literature using the terms CP-99,219, CP-116,519, trovafloxacin, and alatrofloxacin. Abstracts published by the American Society of Microbiology during 1995-1997 meetings were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

All in vitro, animal, and human studies were reviewed for the antimicrobial activity, pharmacokinetics, efficacy, and safety of trovafloxacin.

DATA SYNTHESIS

Trovafloxacin is a new fluoroquinolone with enhanced activity against gram-positive and anaerobic microorganisms. The oral bioavailability under fasting conditions is approximately 88%. The elimination half-life of trovafloxacin is approximately 10 hours. Less than 10% of trovafloxacin is eliminated unchanged in the urine. Trovafloxacin is effective in the treatment of community-acquired pneumonia and nosocomial pneumonia with cure rates of > 90% and 77%, respectively. Trovafloxacin is comparable with ceftriaxone in the treatment of meningococcal meningitis in children; each produces a cure rate of approximately 90%. In treatment of uncomplicated urinary tract infection, both ciprofloxacin and trovafloxacin achieve an eradication rate of > or = 93%. Trovafloxacin is similar to ofloxacin in the treatment of urogenital Chlamydia trachomatis and acute exacerbations of chronic bronchitis, with clinical success in 97% of patients with each drug. The common adverse effects of trovafloxacin include dizziness, headache, and gastrointestinal intolerance.

CONCLUSIONS

The advantages of once-daily dosing and enhanced activity of trovafloxacin against gram-positive and anaerobic organisms may expand its use over available fluoroquinolones. Further studies are needed to define its role in the treatment of various infectious diseases.

Oral ciprofloxacin in the treatment of pseudomonas exacerbations of paediatric cystic fibrosis: clinical efficacy and safety evaluation using magnetic resonance image scanning

Ciprofloxacin is effective for treating pulmonary infection in adult cystic fibrosis patients, and demonstrates excellent efficacy against Pseudomonas aeruginosa, but its use in paediatric cystic fibrosis patients has been limited because quinolone-induced cartilage toxicity has been observed in juvenile animals and has been considered a potential risk for children. Children with cystic fibrosis (n = 26; aged 6-16 years), with proven P. aeruginosa colonization of their sputum, were enrolled into a 14-day, open, non-comparative study. Patients were assigned to twice-daily treatment with oral ciprofloxacin 250 mg, 500 mg or 750 mg, depending on their body weight. None of the patients exhibited any signs or symptoms of arthropathy, as assessed by magnetic resonance imaging of the right knee, during or immediately after treatment, or at the 3-month post-therapy assessment. Cough, sputum production and sputum purulence were improved in more than 70% of patients. Patients showed a mean weight increase of 0.4 kg (95% confidence interval 0.1 to 0.7 kg) over the study period. Only one patient required a repeat chest radiograph, which showed no resolution of the abnormal radiographic appearances. Three patients reported adverse events during the trial, none of which were considered to be related to the study treatment.

Antibiotics in the management of pediatric skin disease

An increasingly large number of antibiotics are available for the treatment of uncomplicated skin and skin structure infections in children. Primary factors in the choice among these agents are the antibiotic resistance profile of the target pathogen(s), and the antibiotic's spectrum of activity, pharmacologic properties, potential adverse reactions and interactions and propensity to select for the emergence of resistant organisms. Based on a consideration of these principles, this article provides a practical guide to the use of antibiotics in the management of common cutaneous infections in the pediatric population.

Effects of ciprofloxacin and ofloxacin on adult human cartilage in vitro

Chondrocyte toxicity and necrosis were seen with electron microscopy after incubation of human adult cartilage biopsy specimens in ciprofloxacin or ofloxacin. In vitro exposure of chondrocytes to fluoroquinolones did not affect apoptosis as determined by flow cytometry. While the immediate clinical significance of this finding remains unclear, the possibility of long-term cartilage damage after fluoroquinolone treatment cannot be excluded.

Ciprofloxacin treatment of bacterial endocarditis involving prosthetic material after cardiac surgery

Two children with cyanotic congenital heart disease and Gram negative bacterial infection of prosthetic material after cardiac surgery were treated successfully with oral ciprofloxacin, initially in combination with netilmicin. The use of oral ciprofloxacin allowed prolonged outpatient treatment to be given, avoiding the need for intravenous access and early repeat surgery.

Ciprofloxacin as antipseudomonal treatment in patients with cystic fibrosis

OBJECTIVE

The efficacy and safety of oral ciprofloxacin as a maintenance antipseudomonal therapy were evaluated in 44 patients with cystic fibrosis who had completed a 14-day regimen of intensive hospital therapy with intravenous ceftazidime and amikacin, supplemented by amikacin inhalation therapy.

METHODS

Twenty-one patients were randomly assigned to oral ciprofloxacin alone (Group I) and 23 received ciprofloxacin plus inhaled amikacin (Group II).

RESULTS

Negative sputum cultures were achieved in 34 patients (77%) at the end of intensive therapy (19 Group I and 15 Group II) and were sustained after 3 months of maintenance therapy in 5 of the 19 responders in Group I (26%) and in 8 of the 15 responders in Group II (53%). Resistance to ciprofloxacin was found in 7 of 31 (23%) sputum isolates at the end of ciprofloxacin therapy. During maintenance therapy, continued improvement in clinical symptoms was observed in 14 patients in both treatment groups; 6 in each group had further improvements whereas only 4 patients were clinical failures. There was no correlation between clinical outcome and either elimination of Pseudomonas aeruginosa from sputum culture or development of ciprofloxacin resistance. Both maintenance regimens were well-tolerated by this population of patients which included 28 children younger than 15 years of age. There were no severe or serious adverse events, no signs of quinolone-related arthropathy and no growth impairment.

CONCLUSION

Ciprofloxacin was efficacious, safe and well-tolerated as maintenance antipseudomonal therapy in cystic fibrosis patients. These results suggest further evaluation of ciprofloxacin as an oral maintenance therapy is warranted.

Antibiotic susceptibility of the newly cultivated agent of human granulocytic ehrlichiosis: promising activity of quinolones and rifamycins

Human granulocytic ehrlichiosis (HGE) is a rapidly emerging tick-borne infection which presents as an acute febrile illness and is associated with hematologic abnormalities, elevated hepatic transaminase levels, and characteristic intracellular organisms in peripheral blood granulocytes. Although HGE has been successfully treated with tetracyclines, its susceptibility to other antibiotics remains unknown. No clear treatment alternative exist for young children, pregnant women, or allergic individuals, in whom tetracyclines are contra-indicated. We performed in vitro antibiotic susceptibility tests with this recently isolated agent grown in the human promyelocytic leukemia cell line HL-60. Doxycycline (MIC, 0.25 micrograms/ml), rifampin (MIC, 0.5 micrograms/ml), rifabutin (MIC, < or = 0.125 micrograms/ml), ciprofloxacin and ofloxacin (both with MICs of 2 micrograms/ml), and trovafloxacin (MIC, < or = 0.125 micrograms/ml) ciprofloxacin and ofloxacin (both with MICs of 2 micrograms/ml), and trovafloxacin (MIC, < or = 0.125 micrograms/ml) demonstrated significant activity against the HGE agent. These agents were also bactericidal. The HGE agent was resistant to clindamycin, trimethoprim-sulfamethoxazole, and imipenem-cilastatin, as well as to ampicillin, ceftriaxone, erythromycin, and azithromycin, antibiotics commonly used to treat Lyme disease. Both chloramphenicol and gentamicin had weak inhibitory activities but were not bactericidal. Our findings confirm the observed clinical efficacy of doxycycline and further suggest that the rifamycins and quinolones, particularly trovafloxacin, hold promise as alternative agents for treating this new infection.

Sequential ciprofloxacin therapy in pediatric cystic fibrosis: comparative study vs. ceftazidime/tobramycin in the treatment of acute pulmonary exacerbations. The Cystic Fibrosis Study Group

BACKGROUND

Cystic fibrosis patients have chronic bacterial infections of the respiratory tract, most commonly Pseudomonas aeruginosa. Although controversial, administration of antibiotic therapy during acute pulmonary exacerbations is standard practice. Fluoroquinolones are currently not indicated for use in young children because of the observation of arthropathy and damage to growing cartilage in beagle puppies. Because of its activity against P. aeruginosa and excellent oral bioavailability, ciprofloxacin offers a unique therapeutic alternative for this patient population.

OBJECTIVE

This prospective, randomized, double blind study compared the efficacy and safety of sequential intravenous/oral ciprofloxacin vs. ceftazidime/tobramycin in hospitalized pediatric cystic fibrosis patients with an acute pulmonary exacerbation associated with P. aeruginosa infection.

METHODS

One hundred thirty patients (ages 5 to 17 years) were randomized to receive either i.v. ciprofloxacin 10 mg/kg every 8 h for 7 days followed by oral ciprofloxacin 20 mg/kg every 12 h for a minimum of 3 days or i.v. ceftazidime 50 mg/kg every 8 h plus i.v. tobramycin 3 mg/kg every 8 h for a minimum of 10 days. Clinical, bacteriologic and safety responses were assessed throughout the study.

RESULTS

All 84 patients (median age, 11 years; range, 5 to 17 years) valid for efficacy in both treatment groups demonstrated clinical improvement. Five patients experienced clinical relapses (3 ciprofloxacin, 2 ceftazidime/tobramycin) by the 2- to 4-week follow-up. Intent-to-treat analysis demonstrated similar clinical findings between the two treatment groups at both the end of therapy and follow-up. Clinical improvement correlated with improvement in pulmonary function studies and the acute clinical scoring system but not with bacteriologic eradication of Pseudomonas. DNA profiles demonstrated that irrespective of colony morphology, usually one clonal strain was associated with each patient's pulmonary exacerbation. Treatment-associated musculoskeletal events occurred with equal frequency (22% vs. 21%) in both study drug groups (n = 129), and arthralgias were within the range of rates for cystic fibrosis arthropathy. None of these events required study drug discontinuation.

CONCLUSION

Sequential i.v./oral ciprofloxacin monotherapy offers a safe and efficacious alternative to standard parenteral therapy for acute pulmonary exacerbations in pediatric cystic fibrosis patients.

Risk-benefit experience of ciprofloxacin use in pediatric patients in the United Kingdom

BACKGROUND

Selection of the most appropriate therapeutic regimen in the management of an infectious disease in a small child or infant is often difficult. Many antimicrobial agents have side effects, thus stressing the importance of risk vs. benefit assessment in the younger patient population. Frequent use of an antimicrobial agent provides the practitioner with critical data regarding the relative rate and intensity of specific adverse events. In addition the benefits of therapy in terms of rapidity of cure, return to normal life and economic outcomes may also be appreciated. Oral ciprofloxacin, although not currently indicated for use in children, has been available to practitioners for > 10 years.

OBJECTIVE

Compassionate use experience with ciprofloxacin for the treatment of acute, serious infections (i.e. Pseudomonas species) in pediatrics is described.

RESULTS

To date ciprofloxacin has been a very useful agent for the management of serious infections in children and has been associated with little risk of permanent joint damage.

CONCLUSION

These data support the use of ciprofloxacin in children in selected situations where the efficacy outweighs any considerable risk, thereby minimizing misuse and overuse of this antimicrobial agent.

Ciprofloxacin in pediatrics: worldwide clinical experience based on compassionate use--safety report

BACKGROUND

Quinolone-induced cartilage toxicity has been observed in experimental juvenile animal studies and is species- and dose-specific. Accordingly these findings have led to the contraindication of fluoroquinolones in children. Previous data in 634 adolescents and children treated with compassionate use ciprofloxacin demonstrated low rates of reversible arthralgia and a safety profile similar to that for adult patients.

OBJECTIVE

This report describes the safety findings in 1795 children who received 2030 treatment courses of intravenous or oral ciprofloxacin.

RESULTS

The average doses of intravenous and oral ciprofloxacin in the study population were 8 and 25 mg/kg/day, respectively. Treatment-associated events were reported in 10.9% of children receiving oral ciprofloxacin compared with 18.9% among intravenous recipients. Overall arthralgia occurred during 31 ciprofloxacin treatment courses (1.5%) and the majority of events were of mild to moderate severity and resolved without intervention. More than 60% of arthralgia episodes were in children with cystic fibrosis.

CONCLUSION

The adverse event pattern in children receiving ciprofloxacin in this analysis was similar to that observed in adults. Rates of reversible arthralgia were low and unchanged from previously published surveillance data in children.

Ciprofloxacin. An updated review of its pharmacology, therapeutic efficacy and tolerability

Ciprofloxacin is a broad spectrum fluoroquinolone antibacterial agent. Since its introduction in the 1980s, most Gram-negative bacteria have remained highly susceptible to this agent in vitro; Gram-positive bacteria are generally susceptible or moderately susceptible. Ciprofloxacin attains therapeutic concentrations in most tissues and body fluids. The results of clinical trials with ciprofloxacin have confirmed its clinical efficacy and low potential for adverse effects. Ciprofloxacin is effective in the treatment of a wide variety of infections, particularly those caused by Gram-negative pathogens. These include complicated urinary tract infections, sexually transmitted diseases (gonorrhoea and chancroid), skin and bone infections, gastrointestinal infections caused by multiresistant organisms, lower respiratory tract infections (including those in patients with cystic fibrosis), febrile neutropenia (combined with an agent which possesses good activity against Gram-positive bacteria), intra-abdominal infections (combined with an antianaerobic agent) and malignant external otitis. Ciprofloxacin should not be considered a first-line empirical therapy for respiratory tract infections if penicillin-susceptible Streptococcus pneumoniae is the primary pathogen; however, it is an appropriate treatment option in patients with mixed infections (where S. pneumoniae may or may not be present) or in patients with predisposing factors for Gram-negative infections. Clinically important drug interactions involving ciprofloxacin are well documented and avoidable with conscientious prescribing. Recommended dosage adjustments in patients with impaired renal function vary between countries; major adjustments are not required until the estimated creatinine clearance is < 30 ml/min/1.73m2 (or when the serum creatinine level is > or = 2 mg/dl). Ciprofloxacin is one of the few broad spectrum antibacterials available in both intravenous and oral formulations. In this respect, it offers the potential for cost savings with sequential intravenous and oral therapy in appropriately selected patients and may allow early discharge from hospital in some instances. In conclusion, ciprofloxacin has retained its excellent activity against most Gram-negative bacteria, and fulfilled its potential as an important antibacterial drug in the treatment of a wide range of infections. Rational prescribing will help to ensure the continued clinical usefulness of this valuable antimicrobial drug.

Pharmacokinetics of ciprofloxacin in pediatric cystic fibrosis patients

The pharmacokinetic characteristics of ciprofloxacin were studied in 10 children with cystic fibrosis, aged from 6 to 16 years, who had completed the standard regimen of intravenous ceftazidime and amikacin. The aim of the investigation was to derive dosing guidelines for young cystic fibrosis patients to be treated with ciprofloxacin. Each child received ciprofloxacin given as two 30-min infusions (10 mg/kg of body weight each) 12 h apart; this was followed by the administration of oral ciprofloxacin (15 mg/kg every 12 h). Blood samples were taken after both infusions and after the first oral dose. A total of 232 ciprofloxacin concentrations (203 concentrations in plasma and 29 concentrations in urine) were analyzed by use of NONMEM and a two-compartment body model with seven parameters: total body clearance (CL), volume of the central compartment (V2), volume of the peripheral compartment (V3), intercompartmental clearance, renal clearance, absorption rate constant, and bioavailability. The influences of weight (range, 18 to 42 kg) and age (range, 6 to 16 years) were investigated. CL (in liters per hour) was found to be linearly correlated with weight (typical value of CL = 8.8 + 0.396. WT, where WT is weight; (interindividual coefficient of variation, 7.8%). V2 and V3 were directly proportional to weight, with slopes of 0.7 and 1.3 liters/kg, respectively. Interindividual variabilities were calculated to be 22.6 and 14.9% for V2 and V3, respectively. No dependency of the other pharmacokinetic parameters on age or weight was seen. Because of the high correlations between age and weight, only one covariable was necessary. Weight had the strongest effect. Bioavailability (population mean) was estimated to be 61.8%, and renal clearance (population mean) was estimated to be 11.4 liters/h. The residual (intraindividual) variability was 31.9%. The protein binding was about 34%, which is similar to the results obtained for adults. In order to define the appropriate dosage regimen for children suffering from cystic fibrosis, a formula was derived so that steady-state concentrations, similar to those obtained in adults after the administration of dosages of 400 mg three times daily intravenously and 750 mg twice daily orally, could be reached. The calculated total daily dose increased with increasing body weight. Given as milligrams per kilogram of body weight, the calculated dosage regimens suggest that for younger children (weight range, 14 to 28 kg), 28 to 20 mg/kg orally twice daily should be given, and for older children (weight range, 28 to 42 kg), 20 to 15 mg/kg orally twice daily should be given. For intravenous administration, dosages of 15 to 10 mg/kg twice daily are sufficient.

The prevalence and clinical features of multi-drug resistant Salmonella typhi infections in Baluchistan, Pakistan

Between January and July 1994, a prospective study of bacteraemia in 692 patients with fever without localizing signs was undertaken at the Quetta Military Hospital in Baluchistan, Pakistan. Salmonella spp. were isolated from 76 (11%) of the patients; 62 had S. typhi and 14 had S. paratyphi A. Significantly more isolations of S. typhi were made in the hot dry months of May and June than in the earlier months. Although multi-drug resistance (to chloramphenicol ampicillin and cotrimoxazole) was detected in 43 (69%) of the S. typhi isolates, it was not found in any of the S. paratyphi A. Defervescence of patients with chloramphenicol-sensitive S. typhi took 7-10 days of chloramphenicol therapy. In contrast, most (91%) of the patients infected with multi-drug resistant S. typhi who were treated with fluoroquinolones achieved defervescence in 1-3 days; the remainder took 4-6 days.