Use of single-dose ofloxacin to eradicate tonsillopharyngeal carriage of Neisseria meningitidis

Progression of antibiotic resistance in Neisseria meningitidis

SUMMARYThe human pathogen Neisseria meningitidis (Nm) is the causative agent of invasive meningococcal disease (IMD), usually presenting as meningitis, bacteremia, or sepsis. Unlike Neisseria gonorrhoeae, antibiotic resistance in Nm has developed slowly. However, in the last two decades and with the reemergence of IMD following the COVID-19 pandemic, antibiotic-resistant Nm isolates, especially to penicillin and fluoroquinolones, have progressively increased. Recent worldwide studies of penicillin intermediate and resistant Nm isolates and the PubMLST global database reveal a notable increase in fully penicillin-resistant isolates since 2016, mediated by mosaic penA alleles or the β-lactamase genes blaROB-1 and blaTEM-1. Fluoroquinolone-resistant isolates, mediated by gyrA mutations, have increased since 2005. Also, while still exceptionally rare, four Nm isolates have been identified with third-generation cephalosporin-resistance since 2011. We review the emergence of antibiotic resistance determinants and lineages in Nm, the resistance to agents previously or currently used in treatment or chemoprophylaxis, and summarize updated treatment and prevention guidelines for IMD. Special populations (e.g., individuals on complement inhibitors) and antibiotic resistance in Nm urethritis isolates are also reviewed. The increasing number of resistant Nm isolates worldwide affects chemoprophylaxis and treatment options for IMD and emphasizes the need for enhanced global surveillance of antibiotic resistance in Nm.

Mass chemoprophylaxis for control of outbreaks of meningococcal disease

Although vaccination is the main strategy used to control meningococcal disease outbreaks, mass chemoprophylaxis has also been used as an immediate response to outbreaks, either to supplement vaccination or when vaccination is not possible. However, public health guidelines regarding the use of mass chemoprophylaxis for outbreak control vary by country, partly because the impact of mass chemoprophylaxis on the course of an individual outbreak is difficult to assess. We have reviewed data for the use of mass chemoprophylaxis during 33 outbreaks that occurred both in military populations and in communities and non-military organisations. In most outbreaks, no additional cases of meningococcal disease occurred after mass chemoprophylaxis, or cases occurred only in individuals who had not received prophylaxis. A delay of several weeks was common before cases occurred among prophylaxis recipients. Overall, the outbreak reports that we reviewed suggest that mass chemoprophylaxis might provide temporary protection to chemoprophylaxis recipients during outbreaks.

Antibiotics for preventing meningococcal infections

BACKGROUND

Meningococcal disease is a contagious bacterial infection caused by Neisseria meningitidis (N. meningitidis). Household contacts have the highest risk of contracting the disease during the first week of a case being detected. Prophylaxis is considered for close contacts of people with a meningococcal infection and populations with known high carriage rates.

OBJECTIVES

To study the effectiveness, adverse events and development of drug resistance of different antibiotics as prophylactic treatment regimens for meningococcal infection.

SEARCH METHODS

We searched CENTRAL 2013, Issue 6, MEDLINE (January 1966 to June week 1, 2013), EMBASE (1980 to June 2013) and LILACS (1982 to June 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs addressing the effectiveness of different antibiotics for: (a) prophylaxis against meningococcal disease; (b) eradication of N. meningitidis.

DATA COLLECTION AND ANALYSIS

Two review authors independently appraised the quality and extracted data from the included trials. We analysed dichotomous data by calculating the risk ratio (RR) and 95% confidence interval (CI) for each trial.

MAIN RESULTS

No new trials were found for inclusion in this update. We included 24 studies; 19 including 2531 randomised participants and five including 4354 cluster-randomised participants. There were no cases of meningococcal disease during follow-up in the trials, thus effectiveness regarding prevention of future disease cannot be directly assessed.Mortality that was reported in one study was not related to meningococcal disease or treatment. Ciprofloxacin (RR 0.04; 95% CI 0.01 to 0.12), rifampin (rifampicin) (RR 0.17; 95% CI 0.13 to 0.24), minocycline (RR 0.28; 95% CI 0.21 to 0.37) and penicillin (RR 0.47; 95% CI 0.24 to 0.94) proved effective at eradicating N. meningitidis one week after treatment when compared with placebo. Rifampin (RR 0.20; 95% CI 0.14 to 0.29), ciprofloxacin (RR 0.03; 95% CI 0.00 to 0.42) and penicillin (RR 0.63; 95% CI 0.51 to 0.79) still proved effective at one to two weeks. Rifampin was effective compared to placebo up to four weeks after treatment but resistant isolates were seen following prophylactic treatment. No trials evaluated ceftriaxone against placebo but rifampin was less effective than ceftriaxone after one to two weeks of follow-up (RR 5.93; 95% CI 1.22 to 28.68). Mild adverse events associated with treatment were observed.

AUTHORS' CONCLUSIONS

Using rifampin during an outbreak may lead to the circulation of resistant isolates. Use of ciprofloxacin, ceftriaxone or penicillin should be considered. All four agents were effective for up to two weeks follow-up, though more trials comparing the effectiveness of these agents for eradicating N. meningitidis would provide important insights.

Safety and immunological outcomes following human inoculation with nontypeable Haemophilus influenzae

BACKGROUND

Nontypeable Haemophilus influenzae (NTHi) exclusively infects humans, causing significant numbers of upper respiratory tract infections. The goal of this study was to develop a safe experimental human model of NTHi nasopharyngeal colonization.

METHODS

A novel streptomycin-resistant strain of NTHi was developed, and 15 subjects were inoculated in an adaptive-design phase I trial to rapidly identify colonizing doses of NTHi. Bayesian analysis was used to estimate the human colonizing dose 50 and 90 (HCD50 and HCD90, respectively). Side effects and immunological responses to whole-cell sialylated NTHi were measured.

RESULTS

Nine subjects were colonized and tolerated colonization well. Immunological analyses demonstrated that 7 colonized subjects and 0 noncolonized subjects had a 4-fold rise in serum levels of immunoglobulin A, immunoglobulin M, or immunoglobulin G. Preexisting immunity to whole-cell NTHi did not predict success or failure of colonization.

CONCLUSIONS

The statistical design incorporated a slow escalation to higher dose levels. HCD50 and HCD90 Bayesian estimates were identified as approximately 2000 and 150 000 colony-forming units, respectively; credible interval estimates were broad. This study provides a potential platform for early proof of concept studies for NTHi vaccines, as well as a way to evaluate bacterial factors associated with colonization.

Antibiotics for preventing meningococcal infections

BACKGROUND

Meningococcal disease is a contagious bacterial infection caused by Neisseria meningitidis (N. meningitidis). Household contacts have the highest risk of contracting the disease during the first week of a case being detected. Prophylaxis is considered for close contacts of people with a meningococcal infection and populations with known high carriage rates.

OBJECTIVES

To study the effectiveness of different prophylactic treatment regimens.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2011, Issue 2) which contains the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE (January 1966 to May Week 3, 2011), EMBASE (1980 to May 2011) and LILACS (1982 to May 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs addressing the effectiveness of different antibiotics for: (a) prophylaxis against meningococcal disease; (b) eradication of N. meningitidis.

DATA COLLECTION AND ANALYSIS

Two review authors independently appraised the quality and extracted data from the included trials. We analysed dichotomous data by calculating the risk ratio (RR) and 95% confidence interval (CI) for each trial.

MAIN RESULTS

We included 24 studies; 19 including 2531 randomised participants and five including 4354 cluster-randomised participants. There were no cases of meningococcal disease during follow up in the trials, thus effectiveness regarding prevention of future disease cannot be directly assessed.Ciprofloxacin (RR 0.04; 95% CI 0.01 to 0.12), rifampin (rifampicin) (RR 0.17; 95% CI 0.13 to 0.24), minocycline (RR 0.28; 95% CI 0.21 to 0.37) and penicillin (RR 0.47; 95% CI 0.24 to 0.94) proved effective at eradicating N. meningitidis one week after treatment when compared with placebo. Rifampin (RR 0.20; 95% CI 0.14 to 0.29), ciprofloxacin (RR 0.03; 95% CI 0.00 to 0.42) and penicillin (RR 0.63; 95% CI 0.51 to 0.79) still proved effective at one to two weeks. Rifampin was effective compared to placebo up to four weeks after treatment but resistant isolates were seen following prophylactic treatment. No trials evaluated ceftriaxone against placebo but ceftriaxone was more effective than rifampin after one to two weeks of follow up (RR 5.93; 95% CI 1.22 to 28.68). Mild adverse events associated with treatment were observed.

AUTHORS' CONCLUSIONS

Using rifampin during an outbreak may lead to the circulation of resistant isolates. Use of ciprofloxacin, ceftriaxone or penicillin should be considered. All four agents were effective for up to two weeks follow up, though more trials comparing the effectiveness of these agents for eradicating N. meningitidis would provide important insights.

Meningococcal carriage by age: a systematic review and meta-analysis

BACKGROUND

Neisseria meningitidis is an important cause of meningitis and septicaemia, but most infected individuals experience a period of asymptomatic carriage rather than disease. Previous studies have shown that carriage rates vary by age and setting; however, few have assessed carriage across all ages. We aimed to estimate the age-specific prevalence of meningococcal carriage.

METHODS

We searched Embase, Medline, Web of Science, the Cochrane Library, and grey literature for papers reporting carriage of N meningitidis in defined age groups in European countries or in countries with a similar epidemiological pattern (where disease caused by serogroups B and C predominates). We used mixed-effects logistic regression with a natural cubic spline to model carriage prevalence as a function of age for studies that were cross-sectional or serial cross-sectional. The model assessed population type, type of swab used, when swabs were plated, use of preheated plates, and time period (decade of study) as fixed effects, with country and study as nested random effects (random intercept).

FINDINGS

Carriage prevalence increased through childhood from 4·5% in infants to a peak of 23·7% in 19-year olds and subsequently decreased in adulthood to 7·8% in 50-year olds. The odds of testing positive for carriage decreased if swabs were not plated immediately after being taken compared with if swabs were plated immediately (odds ratio 0·46, 95% CI 0·31-0·68; p = 0·0001).

INTERPRETATION

This study provides estimates of carriage prevalence across all ages, which is important for understanding the epidemiology and transmission dynamics of meningococcal infection.

FUNDING

None.

Antibiotics for preventing meningococcal infections

BACKGROUND

Meningococcal disease is a contagious bacterial disease caused by Neisseria meningitidis (N. meningitidis). Household contacts have the highest documented risk of the disease during the first seven days of a case being detected. Prophylaxis is, therefore, considered for those in close contact with people with a meningococcal infection and in populations with known high carriage rates as carriers are at increased risk of disease and may pose a risk of infection to others.

OBJECTIVES

To study the effectiveness of different prophylactic treatment regimens in: (1) preventing secondary cases of meningococcal disease after contact with someone with the disease; (2) preventing cases of meningococcal disease in populations with a high rate of N. meningitidis carriers; (3) eradicating N. meningitidis from the pharynx in healthy carriers of N. meningitidis. This review also addresses the issues of adverse effects of prophylaxis and development of drug resistance.

SEARCH STRATEGY

Electronic searches on the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2006), MEDLINE (January 1966 to June 2006), EMBASE (1980 to June 2006), LILACS (1982 to June 2006); and searching of references of all identified studies were performed.

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials addressing the effectiveness of different antibiotic treatments for: (a) prophylaxis against meningococcal disease; (b) eradication of N. meningitidis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently appraised the quality of each trial and extracted data from the included trials. Dichotomous data were analysed by calculating the relative risk (RR) and 95% confidence interval for each trial.

MAIN RESULTS

There were no cases of meningococcal disease during follow up in any of the trials, thus effectiveness regarding prevention of future disease cannot be directly assessed. Ciprofloxacin (RR 0.04; 95% CI 0.01 to 0.12), rifampin (rifampicin) (RR 0.17; 95% CI 0.12 to 0.24), minocycline (RR 0.30; 95% CI 0.19 to 0.45) and ampicillin (RR 0.41; 95% CI 0.25 to 0.66) proved effective at eradicating N. meningitidis one week after treatment when compared with placebo. However, only rifampin (RR 0.20; 95% CI 0.14 to 0.29) and ciprofloxacin (RR 0.03; 95% CI 0.00 to 0.42) still proved effective at one to two weeks. Rifampin continued to be effective compared to placebo for up to four weeks after treatment but resistant isolates were seen following prophylactic treatment. No trials evaluated ceftriaxone against placebo but ceftriaxone was more effective than rifampin after one to two weeks of follow up (RR 5.93; 95% CI 1.22 to 28.68).

AUTHORS' CONCLUSIONS

Given the fact that the use of rifampin in an outbreak setting might lead to the circulation of isolates resistant to rifampin, use of ciprofloxacin or ceftriaxone should be considered. Evidence suggests that all three agents are effective with up to two weeks follow up. Placebo-controlled trials do not seem ethical as prophylactic treatment has been proven to reduce the risk of disease among household contacts. More trials comparing the effectiveness of ceftriaxone, ciprofloxacin and rifampin for eradicating N. meningitidis would provide important insights.

Prophylactic use of antibiotics for prevention of meningococcal infections: systematic review and meta-analysis of randomised trials

A systematic review and meta-analysis of randomised controlled trials was performed in order to study the effectiveness of prophylactic treatment regimens in preventing secondary cases of meningococcal disease (i.e., those contracted after contact with a person with meningococcal disease) and in eradicating Neisseria meningitidis from the pharynx of healthy colonised individuals. The Medline, Embase, and Lilacs databases, the Cochrane Library, and the references of all studies identified were systematically searched for relevant trials. Two reviewers independently applied selection criteria, performed quality assessment, and selected data. Relative risks were pooled using a fixed effects model unless heterogeneity assessed by the I2 statistic and chi-square test was found. In such cases, a random effect model was used. There were no cases of meningococcal disease following treatment with antibiotics or placebo, thus effectiveness regarding prevention of future disease could not be directly assessed. Compared with placebo, ciprofloxacin (RR = 0.04; 95%CI, 0.01-0.12), rifampin (RR = 0.17; 95%CI, 0.12-0.24), minocycline (RR = 0.30; 95%CI, 0.19-0.45), and penicillin (RR = 0.47; 95%CI, 0.24-0.94), proved effective at eradicating Neisseria meningitidis 1 week after treatment. After 1-2 weeks, only ciprofloxacin (RR = 0.03; 95%CI, 0.00-0.42) and rifampin (RR = 0.20; 95%CI, 0.14-0.29) still proved significantly effective when compared with placebo. Rifampin continued to be effective (RR = 0.24; 95%CI, 0.16-0.37) compared with placebo until up to 4 weeks post treatment. Rifampin was the only drug to which resistance developed. Given that the use of rifampin in an outbreak setting might lead to the circulation of isolates resistant to rifampin, the use of ciprofloxacin and ceftriaxone should be considered.

Antibiotics for preventing meningococcal infections

BACKGROUND

Meningococcal disease is a contagious bacterial disease caused by Neisseria meningitidis (N. meningitidis). The highest documented risk of disease is for household contacts during the first seven days of a case being detected. Prophylaxis is considered for those in close contact with people with a meningococcal infection and in populations with known high carriage rates as carriers are at increased risk of disease and may pose a risk of infection to others.

OBJECTIVES

To study the effectiveness of different prophylactic treatment regimens in: (1) preventing secondary cases of meningococcal disease after contact with a case; (2) preventing cases of meningococcal disease in populations with a high rate of N. meningitidis carriers; (3) eradicating N. meningitidis from the pharynx in healthy carriers of N. meningitidis;This review also addresses the issues of adverse affects and development of drug resistance.

SEARCH STRATEGY

Electronic searches on The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2004), MEDLINE (January 1966 to July 2004), EMBASE (1980 to September 2004), LILACS (1982 to July 2004), and searches of references of all identified studies.

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials addressing the effectiveness of different antibiotic treatments for (a) prophylaxis of/against meningococcal disease; (b) eradication of N. meningitidis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently appraised the quality of each trial and extracted data from the included trials. Dichotomous data were analysed by calculating the relative risk (RR) and 95% confidence interval for each trial.

MAIN RESULTS

There were no cases of meningococcal disease during follow up in any of the trials, thus effectiveness regarding prevention of future disease cannot be directly assessed. Ciprofloxacin (relative risk (RR) 0.04; 95% CI 0.01 to 0.12), rifampin (RR 0.17; 95% CI 0.12 0.24), minocycline (RR = 0.30; 95% CI 0.19 to 0.45) and ampicillin (RR 0.41; 95% CI 0.25 0.66) proved effective at eradicating N. meningitidis one week after treatment, compared with placebo. However, after one to two weeks only rifampin (RR 0.20; 95% CI 0.14 to 0.29) and ciprofloxacin (RR 0.03; 95% CI 0.00 to 0.42) still proved effective. No trials evaluated ceftriaxone against placebo. Ceftriaxone was more effective than rifampin, after one to two weeks of follow up (RR 5.93; 95% CI 1.22 to 28.68). Rifampin continued to be effective compared to placebo until up to four weeks of post treatment follow up but resistant isolates were seen following prophylactic treatment.

AUTHORS' CONCLUSIONS

Given the fact that the use of rifampin in an outbreak setting might lead to the circulation of isolates resistant to rifampin, use of ciprofloxacin or ceftriaxone should be considered.Placebo-controlled trials do not seem ethical as prophylactic treatment has been proven to reduce the risk of disease among household contacts. More trials comparing the effectiveness of ceftriaxone, ciprofloxacin and rifampin for eradicating N. meningitidis could provide important insights.

Fluoroquinolones in paediatrics: a risk for the patient or for the community?

Fluoroquinolones are an important group of antibiotics widely used in adult patients because of their excellent tissue penetration and their bactericidal activity. They are not authorised for paediatric use (except the limited indication of pseudomonas infections in cystic fibrosis), however, because of the potential for joint toxicity reported from experiments with young animals. Despite the absence of official approval, fluoroquinolones are widely used in paediatrics as second-line antibiotics when all other treatments have failed. Most of the information available about paediatric use concerns ciprofloxacin, which is used in children much more often than the other members of this class. The published paediatric series have shown that frequency of articular side-effects varies according to age: all the surveys have reported frequencies of around 0.1% in adults and 2-3% in children. Outside of cystic fibrosis and severe infections in which no other treatment is possible, the only paediatric situations where fluoroquinolones are superior to standard treatments for children, in speed of recovery and comfort as well as in efficacy, are typhoid fever, severe shigella dysenteries, and enterobacteria meningitis. Should the use of new fluoroquinolones active against pneumococci be authorised for upper respiratory infections (including recurrent otitis) in children, the potential emergence and dissemination of pneumococci strains in which multidrug resistance includes fluoroquinolones would create a real risk in the community. It is, therefore, important to continue the policy of second-line use in children, only after failure of an earlier treatment, and when other antibiotics approved for paediatric use cannot be used.

Fluoroquinolones in paediatrics

The fluoroquinolones are an important group of antibiotics, which are widely used in adult patients because of their high penetration in tissues and bactericidal activity. However, they are not licensed for paediatric use (except the limited indication of Pseudomonas infection in cystic fibrosis) because of their potential to cause joint toxicity (observed in experiments using juvenile animal models). In recent years, there has been a change in the susceptibility of pathogens to widely used antibiotics; however, many of these pathogens remain sensitive to the fluoroquinolones (agents which can often be administered orally to treat severe infections). Fluoroquinolones have a number of potential indications in children: cystic fibrosis, intestinal infections due to resistant strains of Salmonella spp. and Shigella spp., severe infections due to Enterobacteriaceae (including the neonatal period), complicated urinary tract infections, the immunocompromised host, and some mycobacterial infections. The third generation fluoroquinolones have improved activity against Gram-positive bacteria and could be useful in respiratory tract, and ear, nose and throat infections in adult patients. Their potential role in routine use for paediatric patients will remain limited because of potential joint complications and the availability of other treatment options. However, available clinical data does indicate that the incidence of arthrotoxicity in children treated with ciprofloxacin appears to be the same as that in adult patients. The use of other fluoroquinolones is too rare to obtain meaningful information on their toxicity in children. For future fluoroquinolones, pneumococcal meningitis will probably be a potential indication. Despite their important activity, fluoroquinolones remain a second-line treatment in children, for use following the failure of a well established antibiotic treatment, to avoid potential adverse effects and the emergence of resistant strains.

Update on meningococcal disease with emphasis on pathogenesis and clinical management

The only natural reservoir of Neisseria meningitidis is the human nasopharyngeal mucosa. Depending on age, climate, country, socioeconomic status, and other factors, approximately 10% of the human population harbors meningococci in the nose. However, invasive disease is relatively rare, as it occurs only when the following conditions are fulfilled: (i) contact with a virulent strain, (ii) colonization by that strain, (iii) penetration of the bacterium through the mucosa, and (iv) survival and eventually outgrowth of the meningococcus in the bloodstream. When the meningococcus has reached the bloodstream and specific antibodies are absent, as is the case for young children or after introduction of a new strain in a population, the ultimate outgrowth depends on the efficacy of the innate immune response. Massive outgrowth leads within 12 h to fulminant meningococcal sepsis (FMS), characterized by high intravascular concentrations of endotoxin that set free high concentrations of proinflammatory mediators. These mediators belonging to the complement system, the contact system, the fibrinolytic system, and the cytokine system induce shock and diffuse intravascular coagulation. FMS can be fatal within 24 h, often before signs of meningitis have developed. In spite of the increasing possibilities for treatment in intensive care units, the mortality rate of FMS is still 30%. When the outgrowth of meningococci in the bloodstream is impeded, seeding of bacteria in the subarachnoidal compartment may lead to overt meningitis within 24 to 36 h. With appropriate antibiotics and good clinical surveillance, the mortality rate of this form of invasive disease is 1 to 2%. The overall mortality rate of meningococcal disease can only be reduced when patients without meningitis, i.e., those who may develop FMS, are recognized early. This means that the fundamental nature of the disease as a meningococcus septicemia deserves more attention.

Update on meningococcal disease with emphasis on pathogenesis and clinical management

The only natural reservoir of Neisseria meningitidis is the human nasopharyngeal mucosa. Depending on age, climate, country, socioeconomic status, and other factors, approximately 10% of the human population harbors meningococci in the nose. However, invasive disease is relatively rare, as it occurs only when the following conditions are fulfilled: (i) contact with a virulent strain, (ii) colonization by that strain, (iii) penetration of the bacterium through the mucosa, and (iv) survival and eventually outgrowth of the meningococcus in the bloodstream. When the meningococcus has reached the bloodstream and specific antibodies are absent, as is the case for young children or after introduction of a new strain in a population, the ultimate outgrowth depends on the efficacy of the innate immune response. Massive outgrowth leads within 12 h to fulminant meningococcal sepsis (FMS), characterized by high intravascular concentrations of endotoxin that set free high concentrations of proinflammatory mediators. These mediators belonging to the complement system, the contact system, the fibrinolytic system, and the cytokine system induce shock and diffuse intravascular coagulation. FMS can be fatal within 24 h, often before signs of meningitis have developed. In spite of the increasing possibilities for treatment in intensive care units, the mortality rate of FMS is still 30%. When the outgrowth of meningococci in the bloodstream is impeded, seeding of bacteria in the subarachnoidal compartment may lead to overt meningitis within 24 to 36 h. With appropriate antibiotics and good clinical surveillance, the mortality rate of this form of invasive disease is 1 to 2%. The overall mortality rate of meningococcal disease can only be reduced when patients without meningitis, i.e., those who may develop FMS, are recognized early. This means that the fundamental nature of the disease as a meningococcus septicemia deserves more attention.

Prophylaxis of bacterial meningitis

A comprehensive review of all major agents causing bacterial meningitis--meningococcus of the groups A, B, C, W135, and Y, pneumococcus, and Haemophilus influenzae type B (Hib)--is done in terms of preventing them by chemoprophylaxis or vaccination. Some evidence suggests that the group B meningococcal disease may also be very likely preventable by a vaccine that is already available. Excellent Hib conjugates use a technique that is expected to revolutionize immunoprophylaxis against most meningococcal and pneumococcal diseases in the near future. Unfortunately, the high cost of conjugate vaccines restricts their use in many poor countries.

Upper respiratory tract infections

In reviewing recent advances in upper respiratory tract infections, we focus on five key topics. First, the use of ribavirin in the treatment of respiratory syncytial virus infection has been limited to the immunosuppressed. Prophylaxis in high-risk patients with specific immunoglobulin is effective and a new monoclonal antibody shows promise. Second, the efficacy of neuraminidase inhibitors in the treatment of influenza has become established. There are unresolved concerns about early implementation of therapy without a firm diagnosis; resource implications are enormous. Third, an outbreak of influenza due to avian influenza virus (H5N1) raised the possibility of a new pandemic. However, there was minimal person-to-person spread although much was learned about pathogenesis of infection. Fourth, evidence favoring the use of ciprofloxacin rather than rifampicin for meningococcal chemoprophylaxis is reviewed. Efficacy in eradicating nasopharyngeal carriage is excellent. Finally, the management of sore throat has been considered. This remains controversial but evidence supporting antibiotic therapy in adults is lacking. If treatment is indicated in childhood, shorter courses of antibiotics may be effective.

Clinical applications of quinolones

The quinolone antimicrobials are the class of inhibitors of bacterial topoisomerases that has been developed most fully for clinical use in human medicine. Initial members of the class had their greatest potency against Gram-negative bacteria, but newly developed members have exhibited increased potency against Gram-positive bacteria and soon agents will be available with additional activity against anaerobic bacteria, providing a broad spectrum of potency. After nalidixic acid, the earliest member of the class which was used for treatment of urinary tract infections, the later fluoroquinolone congeners have had sufficient potency, absorption, and distribution into tissue for additional uses in treatment of sexually transmitted diseases, infections of the gastrointestinal tract, respiratory tract, skin, and bones and joints. Tolerability of these agents in usual doses has been good. Acquired bacterial resistance resulting from clinical uses has occurred in particular among staphylococci and Pseudomonas aeruginosa. Intense drug use and ability of resistant pathogens to spread have also contributed to development of resistance in initially more susceptible pathogens such as Escherichia coli and Neisseria gonorrhoeae in certain settings. Preservation of the considerable clinical utility of the quinolone class for the long term will be affected by the extent to which their use is judicious.

Meningococcemia

Meningococcal infection is a contagious disease that is spread via the respiratory route through pharyngeal secretions. Clinical manifestations range from occult bacteremia to overwhelming septicemia or meningitis. Skin manifestations often develop and may be the first sign that leads to clinical suspicion of meningococcemia. Treatment consists of antibiotic therapy and supportive care, which may include aggressive fluid resuscitation, oxygen, ventilatory support, and inotropic support. The use of chemoprophylaxis and in certain circumstances vaccination are important in preventing secondary cases of meningococcal disease.

Quinolones

Fluoroquinolones represent a major advance in antimicrobial chemotherapy. Currently, there are five fluoroquinolones approved by the FDA, and many more quinolones are expected to become available in years to come. Although their clinical utility is constantly expanding, they have been best studied in complicated urinary tract infections, chronic osteomyelitis caused by gram-negative bacilli, bacterial gastrointestinal infections such as traveler's diarrhea and typhoid fever, and uncomplicated gonococcal infections and in the prophylaxis of bacterial infections in patients with neutropenia. These agents have the convenience of oral administration, favorable pharmacokinetic properties, and low toxicity profiles but should be used advisedly because indiscriminate use may result in the early emergence of resistance.

Emergence of a new virulent clone within the electrophoretic type 5 complex of serogroup B meningococci in Norway

An increase in B:15:P1.12 meningococci among isolates from patients with Neisseria meningitidis infection in Norway in recent years led to further characterization of such strains. Between 1987 and 1992, B:15:P1.12 strains constituted 9.8% (24 strains) of B:15 isolates. The B:15:P1.12 strains belonged to the electrophoretic type 5 (ET-5) complex, but 17 (71%) strains were a new clone (ET-5c) not found elsewhere in the world. All but one strain of ET-5c were responsible for a localized outbreak of systemic meningococcal disease in western Norway. A novel monoclonal antibody (202,G-12), developed against the unknown variable region 2 on the class 1 protein of one of these strains, bound to 19 of the 15:P1.12 strains, 4 strains bound the subtype P1.13 reference monoclonal antibody MN24H10.75, and the remaining strain showed no reaction. Sequencing of porA genes demonstrated a series of nine threonine residues in the deduced variable region 2 of the latter strain, while four and five threonine residues were found in the corresponding regions of strains reacting with the monoclonal antibodies 202,G-12 and MN24H10.75, respectively. Epitope mapping with synthetic peptides showed that 202,G-12 bound to a sequence of 11 amino acids which included the four threonine residues specific for subtype P1.13a. Immunoglobulin G antibodies against the P1.7,16 subtype protein, induced in volunteers after vaccination with the Norwegian meningococcal vaccine, did not cross-react on immunoblots with the subtype protein of clone ET-5c. Thus, postvaccination class 1 protein antibodies, assumed to be protective, may not be effective against infection with the new clone.

Fluoroquinolones in paediatrics--1995

The fluoroquinolones are characterised by a broad spectrum of antibacterial activity that includes many Mycobacterium, Chlamydia, Legionella, and Mycoplasma species as well as many multiply-resistant bacterial strains, good oral bioavailability, extensive tissue penetration, low protein binding and long elimination half-lives. Numerous clinical trials have shown that these compounds are effective and well tolerated in the treatment of adult patients with various infections, including urinary tract, respiratory tract, skin and soft tissue, bone and joint, and gynaecological infections, sexually transmitted diseases, infectious diarrhoea, infections in immunocompromised patients, and in surgical prophylaxis. Thus, there is increasing pressure to use this class of drugs in paediatric patients. However, concerns regarding adverse effects, particularly cartilage toxicity, have restricted development of the fluoroquinolone compounds for use in this population. Potential indications include Pseudomonas infections (mainly exacerbations of cystic fibrosis), urinary tract, gastrointestinal and central nervous system infections, infections in immunocompromised patients, certain otorhinolaryngological infections and infections caused by multiply-resistant pathogens. To date, clinical experience gained with fluoroquinolones in paediatric infections, which has been mainly on a compassionate-use basis, indicates that well-designed formal studies should be conducted to fully assess the efficacy and tolerability of these agents in specific indications in children.