Chloramphenicol and tetracyclines

Adsorption Behaviors of Oxytetracycline onto Sediment in the Weihe River, Shaanxi, China

Adsorption behaviors of oxytetracycline onto sediment in the Weihe River were described. The impact factors in the processes of adsorption, such as contact time, solution pH, temperature, and ionic strength, were determined by experiments. The experimental results were analyzed by kinetic and isotherm models. The adsorption kinetics was found to follow a pseudo-first-order model. The equilibrium adsorption data fitted well with the Langmuir and Freundlich isotherm models. However, the Langmuir isotherm was more suitable to describe the adsorption. Thermodynamics parameters such as Gibbs-free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were calculated. Results showed that the adsorption was feasible, spontaneous, entropy increasing, and endothermic in nature, which reached equilibrium in about 24 hours. The adsorption capacity did not cause obvious change at solution pH 4.0–7.0, and both decreased in solution pH 7.0–10.0 and 4.0–2.0. The presence of electrolytes such as NaCl in aqueous solution had a significant negative effect on the adsorption. The mechanisms controlling the adsorption were supposed to be chemisorption.

Effectiveness of ceftriaxone plus doxycycline in the treatment of patients hospitalized with community-acquired pneumonia

BACKGROUND

Limited data exist on the effectiveness of ceftriaxone plus doxycycline in the treatment of patients hospitalized with community-acquired pneumonia (CAP).

METHODS

We performed a retrospective cohort study of all adults hospitalized for pneumonia between January 1999 and July 2001 at an academic medical center. Outcomes were compared for patients with CAP treated with ceftriaxone plus doxycycline versus other appropriate initial empiric antibiotic therapies. Outcomes were adjusted with the use of a propensity score to account for differences in patient characteristics and illness severity between groups.

RESULTS

A total of 216 patients were treated with ceftriaxone plus doxycycline and 125 received other appropriate initial empiric antibiotic therapies. After adjustment, use of ceftriaxone plus doxycycline was associated with reduced inpatient mortality (OR = 0.26, 95% CI: 0.08-0.81) and 30-day mortality (OR = 0.37, 95% CI: 0.17-0.81), but not with length of stay or readmission rates. Analysis of a subset of the sample that excluded patients admitted from nursing homes, patients admitted to the ICU, and patients diagnosed with aspiration also showed reduced inpatient mortality with the use of ceftriaxone plus doxycycline.

CONCLUSIONS

The use of ceftriaxone plus doxycycline as an initial empiric therapy for patients hospitalized with CAP appears safe and effective, and its potential superiority should be evaluated prospectively.

Current use of anti-infectives in dermatology

Dermatologic diseases encompass a broad category of pathologic situations. Infection remains a significant aspect of the pathology faced in patient encounters, and it is natural to expect that anti-infectives play a major element in the armamentarium utilized by dermatologists. Aside from the treatment of the classic bacterial and fungal infections, there are now new uses for antiviral agents to help suppress recurrent disease, such as herpes simplex. There is also the novel approach of using anti-infectives, or agents that have been thought to have antimicrobial activity, to treat inflammatory diseases. This review describes anti-infectives, beginning with common antibiotics used to treat bacterial infections. The discussion will then cover the current use of antivirals. Finally, the description of antifungals will be separated, starting with the oral agents and ending with the topical antimycotics. The use of anti-infectives in tropical dermatology has been purposefully left out, and perhaps should be the subject of a separate review. Cutaneous bacterial infections consist chiefly of those microorganisms that colonize the skin, such as species of staphylococcus and streptococcus. Propionibacterium acnes and certain other anaerobes can be involved in folliculitis, pyodermas and in chronic conditions such as hidradenitis suppurativa.

Tetracycline inhibits development of the infective-stage larvae of filarial nematodes in vitro

In recent years, studies have linked tetracycline treatment of filaria-infected animals with reduced adult worm burdens and decreased levels of microfilaremia. These observations are believed to be attributable to clearance of Wolbachia, intracellular rickettsial-like organisms found within filarial tissues. Although maximal worm reductions were observed when treatment was initiated early in infection, it is not known whether tetracycline inhibits development of infective-stage larvae. To address this issue, we studied the effect of tetracycline on three different species of filarial nematodes, Brugia malayi, Brugia pahangi, and Dirofilaria immitis, in a serumfree in vitro system supporting molting to the fourth larval stage. Tetracycline was capable of inhibiting L3 to L4 molting within a dosage range similar to that reported for susceptible rickettsial organisms. However, Wolbachia DNA could still be detected in nematodes from tetracycline-treated cultures. In addition, three other antibiotics with anti-rickettsial and anti-chlamydial activity (chloramphenicol, erythromycin, and ciprofloxacin) failed to inhibit L3 to L4 molting. Although tetracycline is capable of completely blocking molting of infective-stage larvae, it remains possible that this effect is due to pharmacological activities unrelated to its anti-rickettsial functions.

Ceftriaxone in the treatment of chronic donovanosis in central Australia

OBJECTIVES

To determine the effectiveness of intramuscular (IM) ceftriaxone sodium in the treatment of chronic donovanosis, and the acceptability to patients and staff of supervised outpatient treatment in rural clinics.

METHODS

We collected demographic and sexual health data from participants using a standard questionnaire, and recorded their donovanosis lesions at baseline using genital diagrams. Treatment consisted of a single daily IM injection of 1 g ceftriaxone diluted in 2 ml of 1% lignocaine. Clinic staff followed patients for between three and 12 months, enabling the detection of late recurrences.

SETTING

Rural Aboriginal communities in central Australia.

PARTICIPANTS

The study describes eight women and four men with chronic donovanosis in detail, and summarises the outcome in 12 additional cases. All cases presented with advanced lesions which had failed to heal on the standard oral antibiotic regimens used in the region.

RESULTS

The mean duration of infection was 3.0 years (SD 1.9 years), and between four and ten courses of antibiotics had been prescribed for six of the 12 patients. Patients received between 7-26g of ceftriaxone sodium. Clinical improvement was dramatic in most lesions, and four patients healed completely without recurrence after a total 7-10g of ceftriaxone. Mild recurrences responded to further ceftriaxone or short courses of oral antibiotics. Treatment was well tolerated, and both patient and staff compliance high.

CONCLUSION

Donovanosis is an important cause of chronic genital ulceration in central Australia, and is potentially an important risk factor for HIV transmission in Aboriginal communities. The pharmacokinetics and safety profile of ceftriaxone make it a useful and cost-effective agent in the ambulatory management of donovanosis, especially in remote communities. Supervised multidrug regimens of two or more long-acting agents may provide the best answer in donovanosis, administered through the existing health care infrastructure.