Efficacy and safety of azithromycin as monotherapy or combined with metronidazole compared with two standard multidrug regimens for the treatment of acute pelvic inflammatory disease.

The objective of the study was to compare the efficacy of azithromycin, alone or with metronidazole, versus two standard multidrug regimens for the treatment of acute pelvic inflammatory disease (PID). Patients with PID were treated with once-daily intravenous (i.v.) azithromycin 500 mg for 1 day or 2 days followed by once-daily azithromycin 250 mg orally for a total of 7 days, alone or with three-times-daily metronidazole 400 mg or 500 mg i.v. then orally for a total of 12-14 days. The comparators were either metronidazole + doxycycline + cefoxitin + probenecid or doxycycline + amoxycillin/clavulanate given at standard recommended doses for up to 21 days. In total, 309 patients were treated for PID. The diagnosis was confirmed laparoscopically in 74.8% of patients. Rates of clinical success for azithromycin, alone (97.1%) or with metronidazole (98.1%), were comparable to those for the comparator regimens (94.6%). Eradication rates for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and anaerobes were also comparable for each of the treatment groups. Both azithromycin regimens were well tolerated. In conclusion, azithromycin, alone or with metronidazole, provides a shorter, simpler treatment option for the successful management of acute PID.

Antistreptolysin O and anti-deoxyribonuclease B titers: normal values for children ages 2 to 12 in the United States.

BACKGROUND: Measurement of antibodies to the extracellular antigens produced by group A streptococci, antistreptolysin O (ASO) and anti-deoxyribonuclease B (anti-DNase B), is often necessary to confirm a clinical diagnosis of a previous group A streptococcal infection, especially in patients suspected of having a nonsuppurative sequel to this infection. Age is among several factors that may influence antibody levels in children. Thus, in contrast to adults, what is considered a normal titer for one age group (infants) is not appropriate for another (older children). Age-related "normal" values for ASO and anti-DNase B are provided in the package inserts of commercially available kits; however, there are no recent comprehensive data to validate such values. OBJECTIVE: Using sera from 1131 children (from 23 states) ages 2 to 12 years, we determined age-specific geometric mean titers (GMT) and upper limits of normal (ULN) of ASO and anti-DNase B. METHODS: ASO and anti-DNase B titers were measured by conventional laboratory methods. RESULTS: Children 7 years of age comprised the largest proportion (14%) of the study population. Approximately two-thirds of the sera were collected during winter and early spring months. For both ASO and anti-DNase B, both GMT values and ULN increased with age. The GMTs for ASO and anti-DNase B for the entire group of subjects were 89 and 112, respectively. The ULN for the entire group for ASO and anti-DNase B were 240 and 640, respectively. CONCLUSION: The age-specific values for GMT and ULN for this group of children from 23 states were slightly higher than previously reported. These values are likely representative of the pediatric population in the United States and should be of clinical value to physicians, epidemiologists, and clinical laboratory personnel.

Chlamydia trachomatis-induced production of interleukin-1 by human monocytes.

Human diseases caused by the intracellular bacterium Chlamydia trachomatis include genital tract infections and blinding trachoma. Chlamydial infections are characterized by chronic inflammation and scarring, and development of such complications is thought to be immunologically mediated. In this study, we show that coculture of C. trachomatis (serovar L2) with human blood monocytes induced the production of interleukin-1 (IL-1), an important mediator of inflammation, tissue remodeling, and scarring. IL-1 was produced in response to UV-inactivated elementary bodies containing from 0.1 to 50 micrograms of protein per ml, with a maximal response at 5 to 10 micrograms/ml. IL-1 activity was detected by 6 h of incubation and was maximal by 24 h. Peak levels were maintained throughout 96 h of incubation. Rabbit antibody to human IL-1(alpha + beta) effectively neutralized the thymocyte-stimulating activity of the supernatants. The apparent molecular weight of chlamydia-induced IL-1 was 16,000, as determined by gel filtration on a Bio-Gel P-60 column. Isoelectric focusing yielded two peaks of activity, with pIs of 5.5 and 6.9. Neutralization studies with antisera against human IL-1 alpha and IL-1 beta showed that the acidic and neutral peaks corresponded to IL-1 alpha and IL-1 beta, respectively, with IL-1 beta predominating. Heat-killed chlamydiae, which are not internalized by monocytes, were effective IL-1 inducers, indicating that phagocytosis was not required for IL-1 induction. Purified C. trachomatis lipopolysaccharide was also an effective IL-1 inducer, suggesting that the response to intact organisms may be largely a response to chlamydial lipopolysaccharide. Finally, purified chlamydial major outer membrane protein induced low but detectable IL-1 activity.

Role of tryptophan degradation in respiratory burst-independent antimicrobial activity of gamma interferon-stimulated human macrophages.

To determine whether extracellular tryptophan degradation represents an oxygen-independent antimicrobial mechanism, we examined the effect of exogenous tryptophan on the intracellular antimicrobial activity of gamma interferon (IFN-gamma)-stimulated human macrophages. IFN-gamma readily induced normal monocyte-derived macrophages (MDM) to express indoleamine 2,3-dioxygenase (IDO) activity and stimulated MDM, alveolar macrophages, and oxidatively deficient chronic granulomatous disease MDM to degrade tryptophan. All IFN-gamma-activated, tryptophan-degrading macrophages killed or inhibited Toxoplasma gondii, Chlamydia psittaci, and Leishmania donovani. Although exogenous tryptophan partially reversed this activity, the increases in intracellular replication were variable for normal MDM (T. gondii [5-fold], C. psittaci [3-fold], L. donovani [2-fold]), chronic granulomatous disease MDM (T. gondii [2.5-fold], C. psittaci [5-fold]), and alveolar macrophages (T. gondii [1.5-fold], C. psittaci [1.5-fold]). In addition, IFN-alpha and IFN-beta also stimulated normal MDM to express IDO and degrade tryptophan but failed to induce antimicrobial activity, and IFN-gamma-treated mouse macrophages showed neither IDO activity nor tryptophan degradation but killed T. gondii and L. donovani. These results suggest that while tryptophan depletion contributes to the oxygen-independent antimicrobial effects of the activated human macrophage, in certain cytokine-stimulated cells, tryptophan degradation may be neither sufficient nor required for antimicrobial activity.

Oxygen-independent inhibition of intracellular Chlamydia psittaci growth by human monocytes and interferon-gamma-activated macrophages.

We have demonstrated previously that Chlamydia psittaci grows well in human monocyte-derived macrophages, but to a limited extent in lymphokine-or interferon-gamma (IFN-gamma)-activated macrophages. In this investigation, freshly explanted human monocytes inhibited chlamydial inclusion formation by 85% as compared to macrophages, and the level of inhibition was similar to that exhibited by lymphokine-activated macrophages (79%). To determine whether the oxygen-dependent antimicrobial mechanisms of the mononuclear phagocyte were involved in the inhibition, cells were infected with C. psittaci in the presence of agents that either inhibit the respiratory burst (glucose deprivation) or diminish the effect of H2O2 (catalase). These treatments had no effect on the capacity of monocytes and lymphokine-activated macrophages to restrict chlamydial growth. In addition, monocytes and activated macrophages from an individual with chronic granulomatous disease suppressed chlamydial growth as effectively as normal cells. Oxidatively deficient HeLa and endothelial cells, once stimulated by lymphokine, also displayed normal levels of antichlamydial activity. The induction of this apparently oxygen-independent antichlamydial effect by lymphokine was completely neutralized by a monoclonal anti-IFN-gamma antibody, and could be achieved by treatment with recombinant (r)IFN-gamma alone. These results indicate that the primary antimicrobial mechanism of the human monocyte against C. psittaci is oxygen-independent, and that this response can be effectively stimulated in the macrophage by lymphokine (IFN-gamma).

Activation of tissue macrophages from AIDS patients: in vitro response of AIDS alveolar macrophages to lymphokines and interferon-gamma.

To test the hypothesis that tissue macrophages from AIDS patients have no intrinsic defects in either antimicrobial activity or in the capacity to respond to T cell-derived activating stimuli, alveolar macrophages from 11 patients were treated with crude lymphokines produced by healthy donors. After 72 hr of pretreatment with 10% mitogen- or antigen-induced crude lymphokines (which contained 300 U/ml of interferon-gamma [IFN-gamma]), AIDS alveolar macrophages generated twofold to threefold more H2O2 and readily inhibited the replication of the intracellular pathogens Toxoplasma gondii and Chlamydia psittaci. These responses were indistinguishable from those displayed by activated alveolar cells from 12 non-AIDS patients and three healthy volunteers. As judged by the abrogating effects of a neutralizing anti-human IFN-gamma monoclonal antibody, lymphokine-induced alveolar macrophage activation appeared to be largely IFN-gamma-dependent; thus, macrophages were also stimulated with recombinant (r)IFN-gamma alone. Seventy-two hours of treatment with 300 U/ml of rIFN-gamma resulted in both enhanced oxidative and antimicrobial activity comparable to that achieved by crude lymphokines, and the responsiveness of AIDS alveolar macrophages to rIFN-gamma was identical to control cells. These in vitro results suggest that tissue mononuclear phagocytes from AIDS patients a) are free of apparent defects in intracellular antimicrobial activity, b) are fully responsive to activating T cell products, and c) support the use of IFN-gamma as a potential macrophage-activating immunotherapeutic agent in AIDS-related opportunistic infections.

Gamma-interferon is the factor in lymphokine that activates human macrophages to inhibit intracellular Chlamydia psittaci replication.

We have demonstrated previously that mitogen-induced lymphokines activate human monocyte-derived macrophages to inhibit the intracellular replication of Chlamydia psittaci. To identify the factor(s) in crude lymphokines responsible for this antimicrobial effect, we tested human Con A-induced lymphokines for interferon activity. We also attempted to neutralize the lymphokines with a monoclonal antibody directed against human gamma-interferon and examined the ability of partially purified human gamma-interferon to induce macrophage antichlamydial activity. The lymphokine-induced antichlamydial effect was measured by the inhibition of chlamydial inclusion formation in Giemsa-stained macrophage cultures. Our lymphokines were found to be rich in gamma-interferon; treatment of cells for 48 hr before infection with lymphokines containing 300 U/ml of interferon resulted in an 89% inhibition of chlamydial growth. This lymphokine effect was completely abolished by monoclonal antibody against human gamma-interferon, but not by antisera against human alpha- or beta-interferons. In addition, partially purified human gamma-interferon alone induced macrophages to restrict chlamydial growth by 95%. We conclude that it is the gamma-interferon present in human Con A-induced lymphokines that activates monocyte-derived macrophages to inhibit chlamydial replication.

Killing of intracellular Leishmania donovani by lymphokine-stimulated human mononuclear phagocytes. Evidence that interferon-gamma is the activating lymphokine.

We have found that the crude lymphokines, which prime the human monocyte-derived macrophage to generate H2O2 and exert microbicidal activity against intracellular Leishmania donovani, are rich in interferon (IFN)-gamma (600-3,000 U/ml). To determine the role of this specific lymphocyte product in macrophage activation, lymphokines were pretreated with a monoclonal antibody that neutralizes human IFN-gamma. Antibody exposure completely abolished the capacity of both mitogen- and antigen-stimulated lymphokines to either enhance macrophage H2O2 release or induce leishmanicidal activity. In addition, partially purified and pure recombinant human IFN-gamma were as effective as crude lymphokines in activating macrophages, and 3 d of treatment with 300 U/ml resulted in a seven- to eightfold increase in H2O2 generation and the intracellular killing of both L. donovani promastigotes and amastigotes. The ability of crude lymphokines to induce monocytes and macrophages from a patient with chronic granulomatous disease to kill L. donovani promastigotes was similarly abrogated by anti-IFN-gamma antibody, and could also be achieved by IFN-gamma alone. These results suggest that IFN-gamma is the key macrophage-activating molecule present within human lymphokines, and indicate that IFN-gamma can enhance both the oxygen-dependent and -independent antiprotozoal mechanisms of human mononuclear phagocytes.

Lymphokine enhances oxygen-independent activity against intracellular pathogens.

To determine if mechanisms other than the generation of toxic oxygen intermediates are active against intracellular pathogens, oxidatively deficient mouse L cells and monocyte-derived macrophages from patients with chronic granulomatous disease were stimulated with soluble lymphocyte products. Despite no enhancement in oxidative activity, these cells displayed effective microbistatic activity against both T. gondii and C. psittaci. These results suggest a potential role for nonoxidative mechanisms in the mononuclear phagocyte's activity against intracellular pathogens, and indicate that lymphokines can regulate both oxygen-dependent and oxygen-independent antimicrobial responses.

Differential susceptibility of chlamydiae to exogenous fibroblast interferon.

Mouse fibroblasts (L cells) were incubated for 5 h with 1,000 U of murine fibroblast interferon (MuIFN alpha+ beta) per ml and then were infected with either Chlamydia trachomatis (LGV 440), C. psittaci (6BC), or C. psittaci (Cal 10). Intracellular development of C. trachomatis was reduced 90% in interferon-treated cells 24 h after infection when compared with controls, whereas C. psittaci growth was not affected in interferon-treated cells.

Effect of interferon on the growth of Chlamydia trachomatis in mouse fibroblasts (L cells).

The effect of murine interferon on the growth of the lymphogranuloma venereum biotype of Chlamydia trachomatis (strain 440L) in murine fibroblasts (L cells) was examined. Treatment of infected cell cultures with interferon caused a reduction in the number of inclusion-bearing cells as seen by light and electron microscopy and a decrease in yields of chlamydiae as determined by infectivity assays. Interferon also inhibited cycloheximide-resistant (chlamydia-specific) protein synthesis in infected cells. The interferon effect was dose dependent, with 80 to 90% inhibition occurring at concentrations of greater than 200 IU/ml. The inhibitory effect was neutralized by anti-murine interferon globulin. Interferon did not inactivate extracellular chlamydiae, and both host cell RNA and protein synthesis were required for the development of the interferon-induced antichlamydial state. Inhibition of chlamydial growth by interferon was demonstrable in cells treated 18 h before infection or up to 4 h after infection. Cells infected after interferon was removed exhibited an antichlamydial activity decline which was complete by 30 h after interferon removal. We show that interferon treatment did not affect either entry of chlamydiae into host cells or chlamydial conversion to reticulate bodies but rather caused a reduction in the rate of reticulate body replication.