Effect Of Antimicrobial Therapy Research Articles

Colour of respiratory discharge and antibiotic use

The rise in antibiotic-resistant bacteria has focused attention on the selective pressure caused by widespread use of antibiotics for conditions in which antibiotics are not effective. In particular, patients seem confused about the normal presentation and course of an uncomplicated upper respiratory tract injection (URTI). Although discoloured nasal discharge is a normal self-limited phase of a viral URTI, and randomised placebo-controlled trials have shown no effect of antibiotics on purulent rhinitis or discoloured nasal discharge, patients are confused about the meaning of discoloured nasal discharge. Nearly 80% of adult patients believe antibiotics are effective for an URTI with discoloured nasal discharge. In this confusion about the normal presentation of respiratory infections being transmitted by the primary care physician to the patient? The purpose of our study was to examine primary care physicians’ understanding of the normal presentation and appropriate treatment regimens of URTIs, and acute bronchitis. Questionnaires were sent to 250 primary care physicians (general practitioners, family physicians, and general internists) in each of four states: Minnesota, South Carolina, Texas, and Oregon. The physicians were randomly selected from the American Medical Association’s Physician Masterfile. A total of 211 were returned and not able to be used because the physician either moved, died, or retired from practice. 214 completed questionnaires were returned and used for analysis. We assessed knowledge and current practices of treatment of URTIs with two scenarios representing the normal presentation of an uncomplicated URTI, varying only in the inclusion of discoloured nasal discharge. Similarly, knowledge and practice for acute bronchitis was based on two scenarios representing the normal presentation of acute bronchitis, varying only in the inclusion of purulent sputum. When the scenario presented an adult with symptoms of an URTI, physicians were more likely to diagnose sinusitis than an URTI when the nasal discharge was described as discoloured (table). Antibodies were prescribed seven times more frequently when the nasal discharge was discoloured. Even respondents who labelled both scenarios as an URTI were 5·6 times more likely to use an antibiotic when the nasal discharge was discoloured than when it was clear (28% vs 5%, p<0·001). In the second scenario which presented an adult with a cough following URTI symptoms, when the sputum was described as discoloured physicians were more likely to label the illness as bronchitis and prescribe antibiotics (table). Interestingly, physicians were more likely to use a bronchodilator for cough with clear sputum. In both the clear and purulent sputum scenarios, bronchodilators have been shown to have some asymptomatic benefit for patients with acute bronchitis regardless of sputum colour while antibiotics are of questionable effectiveness. This small study shows that physicians assign a great deal of predictive value to the colour of nasal discharge or sputum despite evidence that the appearance of these secretions alone is not predictive of bacterial infection or the effectiveness of antimicrobial therapy. Patients appear to have learned this interpretation of discoloured secretions from physicians and may bring expectations of receiving antibiotics for illnesses into the physician-patient encounter. These misperceptions may contribute to the inappropriate prescribing of antibiotics and may be a factor in the development of antibiotic-resistant strains of common pathogens.

Experience with a hospital-wide outbreak of vancomycin-resistant enterococci

Background: Vancomycin-resistant enterococci (VRE) were first detected in our institution in 1991. An outbreak was recognized in late 1992 when there was a sudden rise in the number of patients per month with VRE. Little information exists concerning the natural history of infection with these pathogens, and the effect of antimicrobial therapy is unclear. Recent guidelines emphasize prudent use of vancomycin and prompt institution of barrier precautions to limit the spread of vancomycin resistance. Methods: Data were obtained by review of microbiologic and clinical records. Patients were categorized according to site of infection, and outcome of therapy was assessed. Hospital antibiotic usage was analyzed to determine any correlation with the outbreak. Infection control measures instituted in 1993 included patient isolation, environmental cleaning, and a reemphasis of barrier precautions. Surveillance cultures were performed to assess the extent of the outbreak in January 1995. Results: VRE were detected in clinical cultures from 159 patients 1991 through 1994. Mortality rate was 48%, but in most cases death could not be attributed to enterococcal infection. Patients with wound infections healed without specific therapy. Many patients with bacteremia had resolution with ampicillin or without specific therapy. Patients were widely scattered throughout the hospital from the beginning of the outbreak. Hospital usage of cefotaxime correlated with the number of cases. Infection control measures were not successful. Surveillance culture results in January 1995 revealed that 53% of all medical and surgical inpatients had fecal colonization with VRE. Genetic analysis of selected isolates revealed that one strain predominated, but at least seven distinct strains were identified. Conclusions: Our data suggest that many infections with VRE resolve without specific therapy. The infection control measures we used were ineffective, possibly because of the multiple strains present in our hospital. Isolation of all patients with VRE is impractical when there is widespread fecal carriage.

Investigative Urology: The Effect of Antimicrobial Therapy on Testicular Aspirate Flow Cytometry

Many antibiotics have been shown to have adverse effects on spermatogenesis. Deoxyribonucleic acid (DNA) flow cytometry of testicular aspirate has been shown to be an effective method of quantitatively evaluating testicular function. To assess this problem, DNA flow cytometry of testicular aspirate was performed on 8 groups of rats, each of which received antibiotics via daily gavage for 10 days. Aspirations were performed on days 0, 11 and 56. Data thus obtained were analyzed using a two-way ANOVA with repeated measures. Antibiotics studies included ciprofloxacin 15 mg./kg./day, sulfamethoxazole (SMX) 20 mg./kg./day (with trimethoprim (TMP) 4 mg./kg./day), nitrofurantoin 7 mg./kg./day, ofloxacin 10 mg./kg./day, lomefloxacin 6 mg./kg./day, doxycycline 3 mg./kg./day and norfloxacin 10 mg./kg./day. One group received the same SMX/TMP dose, together with folate 0.014 mg./kg./day. A statistically significant change in aspirate content on day 11 as compared with baseline existed in groups receiving TMP/SMX (p = 0.00025), nitrofurantoin (p = 0.0000043), ofloxacin (p = 0.000075) and doxycycline (p = 4.89 X 10(-9). Control rats and the group receiving TMP/SMX with folate showed no significant change. On day 56 the abnormality persisted in groups TMP/SMX (p = 0.042), nitrofurantoin (p = 0.001), ofloxacin (p = 0.036) and doxycycline (p = 0.003). Controls and groups receiving ciprofloxacin, norfloxacin and lomefloxacin continued to show no statistically significant difference from baseline on day 56. These data suggest that SMX/TMP, nitrofurantoin, ofloxacin and doxycycline significantly alter spermatogenesis. Ciprofloxacin, norfloxacin and lomefloxacin had no apparent effect on spermatogenesis as measured by DNA flow cytometry.

Effect of antimicrobial therapy on the gastrointestinal bacterial flora, infection and mortality in mice exposed to different doses of irradiation

The effect of antimicrobial therapy on gut flora, sepsis, and mortality was investigated in C3H/HeN female mice irradiated with 7.0, 8.0 or 8.5 Gy or 60Co. The antimicrobial agents tested were metronidazole, penicillin, imipenem, gentamicin and ofloxacin. In control mice, the greatest reduction of lactose fermenting organisms (1.7-2.8 logs) occurred on day 8 after irradiation and were related directly to radiation doses. After day 8, lactose fermenting organism levels increased and the increases were associated with mortality due to Enterobacteriaceae sepsis. Irradiation reduced the populations of strict anaerobic bacteria in control mice by 2-8 logs, and these remained at low levels. Treatment with either metronidazole or penicillin resulted in greater reductions of strict anaerobic bacteria than occurred in the controls and induced earlier and greater increases in lactose fermenting organisms and associated mortality. Therapies with either gentamicin or ofloxacin resulted in lesser reductions of strict anaerobic bacteria (1.1-2.2 logs) than occurred in controls, and caused greater decreases in lactose fermenting organisms and mortality. The changes in the bacterial flora and mortality following imipenem treatment were similar to controls. These data demonstrate that in animals exposed to irradiation, antimicrobial agents effective against strict anaerobic bacteria can be deleterious, but antimicrobial agents effective against lactose fermenting organisms may be beneficial.

Leptospirosis with Acute Acalculous Cholecystitis and Pancreatitis

Severe Leptospira autumnalis infection was associated with acute acalculous cholecystitis and pancreatitis in a 66-year-old man. He was successfully treated with antimicrobial agents and supportive therapy, including hemodialysis. We review these uncommon manifestations and the effectiveness of antimicrobial therapy in advanced leptospirosis.

Effect of antimicrobial therapy on the specific serological response to Helicobacter pylori infection.

The systemic immune response to Helicobacter pylori was studied in 247 infected adult patients before antimicrobial therapy and at different intervals following therapy. Endoscopy with simultaneous collection of biopsies was performed in all patients immediately before treatment, 4 to 6 weeks after the end of therapy and 6 to 12 months later. A 14C-urea breath test was performed 3 to 6 months after the end of treatment. Biopsy specimens were cultured and examined histologically using Giemsa stain. Sera were tested for Helicobacter pylori IgG antibodies with a commercial enzyme immunoassay using species-specific antigens. Overall, Helicobacter pylori was eradicated in 120 patients while the other 127 remained infected with the organism. The follow-up period ranged from 4 weeks to 33 months (mean 10.2 months). Pretreatment IgG levels did not differ significantly between the two groups of patients. Six weeks after the end of treatment a slight but definite decrease in the IgG antibody levels was seen irrespective of treatment success. In the 127 patients who remained Helicobacter pylori-positive, the level of IgG antibodies remained stable or increased with time. A continuous fall in antibody levels was observed following bacterial eradication in the other 120 patients, but the difference in antibody levels between treatment responders and nonresponders became significant only more than six months after the end of treatment (p = 0.001). Serological testing may be useful for monitoring the outcome of long-term treatment of Helicobacter pylori infection and obviate the need for endoscopy.

The effect of antimicrobial therapy on mixed infections with Bacteroides species. Is eradication of the anaerobes important?

Antimicrobial agents were used alone or in combinations in order to explore their effect on mixed aerobic-anaerobic infections. Subcutaneous abscesses were induced in mice by single and mixed infections of Bacteroides fragilis, Bacteroides melaninogenicus, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The infected animals were treated for 5 days with spiramycin, gentamicin or metronidazole alone, or metronidazole combined with spiramycin or gentamicin. Animals were killed 5 days after inoculation and the bacterial contents of the abscesses determined. Infection induced by a single species of bacteria always responded to appropriate antimicrobial therapy. In infections caused by two species of organisms, however, therapy directed at either the Bacteroides sp. (with metronidazole) or the aerobes or facultative anaerobes (with spiramycin or gentamicin) was effective not only in significantly reducing the numbers of the target organism but also, in 13 of 24 instances, in reducing to a small extent the numbers of the other bacteria. Despite this phenomenon, in no instance did therapy with a single agent eliminate the infection and eradicate the untargeted organism. The combination of spiramycin and metronidazole increased the reduction in numbers of B. melaninogenicus in single-organism infections and of Bacteroides sp. in mixed infections with S. aureus and S. pyogenes. These findings support the need to aim treatment at all components of mixed infections.

Bacteremia in Basrah University Teaching Hospital: Incidence, Microbiologic Features, and Therapeutic Pattern

From February 1984 to October 1986, a total of 4369 blood cultures were obtained from patients at Basrah University Teaching Hospital. Among these, 227 (5.2%) were bacteriologically positive, givin...

Effects of antimicrobial therapy on sperm-mucus interaction.

Sperm-mucus interaction under in-vitro or in-vivo conditions might be affected by microorganisms colonizing the reproductive tract. In order to study the influence of antimicrobial therapy, an extensive microbial screening was performed including Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, a broad spectrum of potentially pathogenic aerobic and anaerobic bacteria, Trichomonas vaginalis, herpes simplex virus and yeasts. One-hundred-and-six couples with a mean duration of infertility of 5.5 years (range 1-12 years) and with isolation of potentially pathogenic microorganisms in semen samples and/or cervical swabs were submitted to a prospective pilot study. None of the patients displayed signs or symptoms of infection in the lower genital tract. Before and after specific therapy, based on antimicrobial susceptibility testing, sperm analyses and in-vitro sperm penetration meter tests (SPMT) (Kremer) were performed. SPMT was evaluated with cervical mucus of patients' wives, collected after a standardized oral treatment with oestrogens and, additionally, in a crossed manner with cervical mucus and spermatozoa of fertile donors. The success of antimicrobial therapy was controlled by repeating the same microbial screening and was 96%. However, there was a marked change in the microbial pattern. A comparison of the results of sperm analyses before and after treatment revealed neither significant differences for sperm volume, sperm count, propulsive motility, morphology, vitality, pH, fructose concentration or number of round cells, nor was there a significant influence on the cervical index and the number of leukocytes in cervical mucus.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of antimicrobial therapy on bowel flora and bacterial infection in irradiated mice.

Mice exposed to 10 Gy cobalt-60 radiation were given intramuscular antimicrobial therapy of gentamicin, or metronidazole, or a combination of the two. Mortality in the mice treated with metronidazole alone or in combination with gentamicin occurred earlier than in the controls (P less than 0.001). Microorganisms were recovered from the blood, spleen, and liver of the metronidazole-treated mice earlier than from other groups. The predominant organisms recovered from these animals were Enterobacteriaceae. Quantitative cultures of the ileal flora showed a decrease in the number of aerobic, facultative anaerobic and strict anaerobic bacteria after irradiation, and a subsequent increase only in the number of strict aerobic bacteria. As compared to untreated mice, a rapid decrease (by 8.8 logs) in the number of anaerobic flora occurred in the mice treated with metronidazole 5 days after irradiation. This was followed by a rapid increase in the number of aerobic organisms which coincided with the earlier mortality in this group. These data suggest that antimicrobial agents that decrease the number of the strict anaerobic component of the gut flora enhance systemic infection by aerobic or facultative anaerobic bacteria, and this facilitates mortality after irradiation.

Orbital infections in the immunocompromised patient.

In humans, a variety of immunodeficiency states have been recognized whereby infectious agents gain access to the body and produce disease. The orbit may become involved following injury or surgery, through spread of infection from surrounding structures, or by metastatic seeding from a distant source. Orbital infections associated with immunodeficiency represent a special problem in diagnosis and management for the ophthalmologist. Twenty-four patients with immunodeficiency-associated orbital infections who illustrate a wide range of factors associated with immunodeficiency, agents that produce infection, ophthalmic signs that result, and effects of antimicrobial therapy are presented.

Effects of antimicrobial therapy on faecal bulking.

It has recently been postulated that dietary fibre acts as a substrate for colonic flora, and that the resultant microbial growth bulks the faeces. Antimicrobial therapy was used in this study to assess the effect of reduction in colonic microbial proliferation on faecal output in human subjects on a constant dietary fibre intake. Six healthy young male subjects were maintained on constant daily diets and metronidazole (1 g/day) and ampicillin (1 g/day) were administered in divided doses for one week after an initial baseline study period of two weeks. After antimicrobial therapy, mean faecal weights rose from 176.0 +/- 27.0 g to 348.1 +/- 37.7 g/day. Faecal solids increased from 32.9 +/- 4.2 g to 46.1 +/- 5.8 g/day. Faecal neutral detergent fibre increased from 1.92 +/- 0.42 g to 15.19 +/- 2.58 g/day. The mean transit times and mean daily faecal nitrogen remained the same, both before and after treatment. Substantial breakdown of dietary fibre occurs in the human colon which may decrease faecal bulk, suggesting that water holding by dietary fibre is probably of greater importance for faecal bulking.

Skin and skin structure infections in the patient at risk: Carrier state of staphylococcus aureus

Staphylococcus aureus is a ubiquitous organism that is normally carried on the skin and body surfaces of man. The nares are sites frequently colonized, and patients and hospital personnel represent the major source of infection. The occurrence of staphylococcal infection depends on the availability of staphylococci and the host resistance to infection. Factors that influence the carrier rate of S. aureus include minimal colonizing dose, effects of antimicrobial therapy, disinfectants in the environment, coincidental respiratory infections, possible effect of immune factors, duration of hospital stay, and regular needle injections. Certain patients such as drug abusers, patients with diabetes, and patients with chronic renal failure are at high risk of S. aureus infections. Although underlying immune deficiencies are present, increased carrier rate also might be related to regular needle use, as shown among allergy patients. The significance of carrier state has been defined in outbreaks in hospital nurseries, postoperative patients, and systemic infections such as endocarditis in the drug abuser, the toxic shock syndrome, and dermatologic infections.

Analysis of 1,186 Episodes of Gram-Negative Bacteremia in Non-University Hospitals: The Effects of Antimicrobial Therapy

Over the five-year period 1977-1981, we studied 1,186 episodes of bacteremia due to Enterobacteriaceae and Pseudomonadaceae in the four non-university hospitals of a single metropolitan area. Overall patient mortality was 36.3%, and mortality attributed specifically to infection was 19.0%. The importance of severity of underlying disease, site of infection, microorganism, and age--previously determined to be prognostic factors in studies conducted at tertiary-care centers--was confirmed. Appropriate initial antimicrobial therapy (defined as the administration of an effective agent in adequate dose and by a suitable route of administration on the first calendar day on which blood cultures were positive) did not improve survival compared with the use of an ineffective antimicrobial agent or no therapy at all. However, appropriate antimicrobial therapy subsequent to the first calendar day on which blood cultures were positive clearly affected survival. These findings confirm previous conclusions regarding the frequency and severity of gram-negative bacteremia and the overall impact of antimicrobial therapy on this condition. These studies also suggest the possibility that the definition of optimal initial therapy in some groups of patients should be reconsidered.

Reflux Nephropathy: Effects of Antimicrobial Therapy on the Evolution of the Early Pyelonephritic Scar

No AccessJournal of UrologyAbstracts1 Feb 1983Reflux Nephropathy: Effects of Antimicrobial Therapy on the Evolution of the Early Pyelonephritic Scar P.G. Ransley and R.A. Risdon P.G. RansleyP.G. Ransley More articles by this author and R.A. RisdonR.A. Risdon More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(17)52136-9AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "Reflux Nephropathy: Effects of Antimicrobial Therapy on the Evolution of the Early Pyelonephritic Scar." The Journal of Urology, 129(2), p. 440 © 1983 by The American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 129Issue 2February 1983Page: 440 Advertisement Copyright & Permissions© 1983 by The American Urological Association Education and Research, Inc.MetricsAuthor Information P.G. Ransley More articles by this author R.A. Risdon More articles by this author Expand All Advertisement PDF downloadLoading ...

Reflux nephropathy: Effects of antimicrobial therapy on the evolution of the early pyelonephritic scar

The importance of vesicoureteric reflux (VUR) and its extension into the pyelotubular system of the kidney (intrarenal reflux) in the genesis of segmental renal scarring during childhood (nonobstructive chronic pyelonephritis; reflux nephropathy) is now well established [1–3]. Papillary morphology determines the distribution of intrarenal reflux (IRR) and subsequent scar formation [3–6]. There is still considerable controversy whether scarring may occur following intrarenal reflux of sterile urine [7, 8] or whether urinary infection is an essential prerequisite [3, 9]. Germane to this argument is the clinical observation that most patients with reflux nephropathy have renal scars when first seen and the development of completely new scars is a distinctly rare event [10]. The finding of sterile urine in the presence of established scarring does not mean that infection never occurred or that it is unimportant in the pathogenesis of the scarring process. The possibility exists that scarring may develop very quickly in the presence of reflux of infected urine, perhaps even during the first episode of urinary tract infection. The present experimental study was undertaken to see how quickly parenchymal damage and scarring might occur in the presence of reflux of infected urine and to establish how treatment might modify the response.

794 YERSINIA ENTEROCOLITICA GASTROENTERITIS IN CHILDREN

Y. enterocolitica (YE) is the second commonest cause of bacterial gastroenteritis (GE) in children in the Montreal area. The purpose of this study is to define prospectively the incidence of YE GE, duration of carriage, serological response, communicability in households, and effect of antimicrobial therapy. Clinical, bacteriologic and serologic surveillance was performed on index cases (IC) and their family members until all members of the family had 3 consecutive negative stools. During the first 6 mo of the study 96 IC were identified from 2531 ill children. In 31 IC whose clinical and epidemiologic data were available, diarrhea (100%), fever (71%) and abdominal pain (61%) were major symptoms with mean duration (D) of 16, 4 and 9 days respectively. D of excretion of YE was 4.5 wks (range 2-9). Paired sera were available from 25 IC; all but 2 (both under age 4.5 mo) showed a serologic response. The geometric mean titer of the 1st serum from those ≥1 yr (18) was 635, compared to 100 for those ≥1 yr (7). Intrafamilial spread was documented by at least 2 of 3 criteria (clinical, bacteriologic, or serologic) in 7 of 25 families, involving 4 of 13 children and 3 of 53 adult household contacts. It is too early to evaluate the effect of therapy. Our findings indicate that (1) YE is a frequent cause of GE in children; (2) YE GE is followed by “O” type-specific antibody response in children ≥1 yr of age; and (3) intrafamilial spread is often asymptomatic.

Effect of antimicrobial therapy on lung bacterial clearance in the burned rat

Effect of antimicrobial therapy on lung bacterial clearance in the burned rat

Effect of antimicrobial therapy on lung bacterial clearance in the burned rat.

Effect of antimicrobial therapy on lung bacterial clearance in the burned rat.

The effect of antimicrobial therapy on the prognosis of primary tuberculosis in children.

The effect of antimicrobial therapy on the prognosis of primary tuberculosis in children.