The fluoroquinolones as treatment for infections caused by gram-positive bacteria

The fluoroquinolones have become attractive options as treatment for a broad range of infections caused by Gram-negative bacteria. However, the value of these antibiotics to patients with infections caused by Gram-positive pathogens remains controversial. Experience with quinolones as therapy for skin and skin structure infections, osteomyelitis and peritonitis in patients receiving continuous ambulatory peritoneal dialysis suggests that the concerns which have been expressed about the use of these agents against methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis and streptococci are justified; indeed, the frequent emergence of quinolone-resistant strains of MRSA and coagulase-negative staphylococci either during or following treatment is now well documented. The fluoroquinolones should be prescribed with caution to patients with community-acquired pneumonia or whenever severe infection of pneumococcal aetiology is proven or suspected. As prophylaxis for the granulocytopenic patient, quinolones such as norfloxacin and ciprofloxacin have been shown to be effective in reducing the incidence of morbidity attributable to Gram-negative bacteria, but they have not significantly affected the incidence of infection caused by Gram-positive bacteria. In the treatment of febrile episodes in the neutropenic patient, ciprofloxacin, the quinolone investigated most extensively in this clinical setting, produced high cure rates only when it was combined with an antibiotic which was predictably active against Gram-positive organisms. We review here the role of currently-available fluoroquinolones (norfloxacin, enoxacin, pefloxacin, ofloxacin and ciprofloxacin) as treatment for these and other infections.     

Multicenter study of isolated micro-organisms resistant to antimicrobials in 10 Portuguese hospitals in 1994

In 1994, Microbiology Laboratories of ten Portuguese hospitals analysed isolated microorganisms found in blood and urine samples and studied antimicrobial susceptibilities of the most frequent bacterial pathogens. From 63780 blood samples, the most frequent were Staphylococcus spp. and from 69189 urine samples significant numbers of Escherichia coli, Enterococcus spp., Pseudomonas aeruginosa and Candida spp. were isolated. Escherichia coli strains (c.7000) revealed a low percentage of resistance to antibiotics with the exceptions of ampicillin (48%) and co-trimoxazol (25%). Klebsiella pneumoniae isolates (c.2000) revealed important resistance to ampicillin (98%), cephalotin (31%), co-trimoxazol (38%) and gentamicin (28%), while values for 3rd generation cephalosporins varied among hospitals, with several strains showing phenotype of extended-spectrum beta-lactamase. A great variation in resistance values of P. aeruginosa (c.4000) was found in relation to the antibiotics as well as to the hospitals. Resistance to methicillin in S. aureus (c.6000) was high, reaching an average of 47%, and it was even higher with S. epidermidis (c.3000) and S. haemolyticus (c.650). Only vancomycin was always active against these strains. In E. faecalis (c.2500) resistance was of 2% to ampicillin, 35% to gentamicin, 45% to streptomycin and 1% to vancomycin. E. faecium isolates (c.300) showed the most worrying results with 70% resistance to ampicillin, 42% to gentamicin, 59% to streptomycin and 9% (30 strains isolated in 5 hospitals) to vancomycin. Vancomycin resistant strains were also resistant to all other antibiotics.     

Fever and neutropenia in children with malignant disease

Treatment of episodes of fever and neutropenia in pediatric hematology-oncology patients includes hospitalization and administration of intravenous antibiotics until the patient is afebrile and no longer neutropenic. The present analysis characterizes retrospectively febrile episodes in neutropenic pediatric hematology-oncology patients with regard to frequency of documented infections, organisms associated with these infections, efficacy of a standardized antibiotic regimen, and safety of early antibiotic discontinuation under defined conditions. A total of 149 pediatric febrile neutropenic episodes were identified during a 4-year period between 1990 and 1994. These occurred in 47 male and 19 female patients, of a mean age of 7.6 years (range 0.5-15). The most frequent diagnoses were leukemia (41% of patients), lymphoma (21%), rhabdomyosarcoma (7%), soft tissue sarcoma (5%), Ewing's sarcoma (5%), and osteosarcoma (4%). Infection was certain in 36% of febrile episodes, probable in 14%, and not determined in 50%. Patients with severe neutropenia (absolute neutrophil count < 100) had a slightly, although not significantly higher incidence of documented and probable infection (57%). Patients with solid tumor had documented infection in 40% of their febrile episodes, and the detection rate in the children with leukemia was 31% (P < .20) Blood cultures were positive in 21 (14%) of 149 episodes. Staphylococci (both coagulase-negative and coagulase-positive strains) and Pseudomonas were the organisms most frequently isolated (six episodes each). Mouth and throat (11), lungs (10), and skin (10) were the next most frequent sites of localized infection. Initial treatment consisted of piperacillin and amikacin or of vancomycin and amikacin when the source of fever was thought to be an infected central line catheter, with addition of amphotericin B by the seventh day of treatment when fever with neutropenia persisted or upon clinical suspicion of underlying fungal infection. There was a single fatality, of a patient with Burkitt's lymphoma. Antibiotics were discontinued when initial blood cultures had no growth after at least 48 hours and no source of infection was found, the blood count was improving, and if the patient became afebrile and clinically well. No patient needed readmission during the fortnight that followed discontinuation of antimicrobial therapy. Patients with negative blood cultures under defined conditions, as described above, could safely be discharged early, thus shortening the duration of intravenous antibiotic therapy and hospital stay.     

N-acetyl cysteine attenuates acute lung injury in the rat

Bacterial infections, especially cholangitis, are still common complications after liver transplantation (LTx). During recent years, multiresistant enterococci have become a nosocomial problem in transplant units. The present prospective study on 26 patients, including 24 patients with chronic liver disease, demonstrated that enterococci were the predominant micro-organism involved in post-LTx bacterial infections. They were cultured in the feces and in other sites of 10 out of 13 (77%) patients who underwent extensive examinations. Ampicillin-resistant Enterococcus faecium strains were isolated in urine or feces of 2 of the 13 patients prior to LTx. Similarly, resistance to ampicillin and gentamicin, the empirically used antibiotics for patients with fever of unknown origin, was found in E. faecium strains in 3 and 2 patients, respectively. Moreover, multiresistant E. faecium and E. faecalis strains were demonstrated in 46% of the patients in the postoperative period (3 months). However, no vancomycin-resistant enterococci were isolated. The use of antibiotics within 4 months prior to LTx significantly increased the risk of developing ampicillin-resistant bacteria at the time of LTx and of infections with bacteria of enteric origin after LTx (P = 0.03 and 0.01, respectively). We conclude that stool and urine cultures performed prior to LTX may be useful for selecting prophylactic antibiotic regimens.     

Outpatient antibiotic treatment in low-risk febrile neutropenic cancer patients

Traditionally febrile neutropenic patients have been treated with parenteral antibiotics in an inpatient setting; however, recent work by several investigators has demonstrated successful treatment with both parenteral and oral antibiotics in an ambulatory environment. This has been accomplished by identification of low-risk neutropenic patients, advances in broad-spectrum antibiotics with long half-lives and stabilities, the introduction of the oral quinolones, home health-care initiatives, improvements in vascular access devices, and development of technically enhanced antibiotic delivery systems. Outpatient antibiotic therapy for febrile episodes in low-risk neutropenic patients should now be considered an acceptable alternative to hospital-based treatment. This review focuses on the development and rationale of risk stratification and examines the results of various outpatient antibiotic trials recently completed.     

The characteristics of the causative agents of suppurative-inflammatory complications in hemophiliacs

Morphological-cultural and physiological-biochemical properties of 24 strains of microorganisms agents of pyo-inflammatory complications of different localization in patients with hemophilia have been studied. Microorganisms strains presented by the following species: Staphylococcus aureus, S. epidermidis, S. saprophyticus, Proteus vulgaris, P. morganii, Hafnia alvei, Serratia marcescens, have been identified. It was found out that in monoculture staphylococci prove to be the leading etiological agent (60.9%), gram-negative enterobacteria (52.2%) and bacterial associations (8.7%) occur more rarely. Special attention was paid to the study of resistance of antibiotics, circulation and pathogenicity factors that had a direct effect on the main disease severity. It was ascertained that high activity of enzymes and presence of pathogenicity factors were the peculiarities of microorganisms isolated from pyo-septic sites in patients with hemophilia. All the strains possessed multiple resistance to antibiotics.     

History of sexual abuse among HIV-infected women

OBJECTIVE: To study the changes in patterns and resistances of bacteria from patients with bacteremia in 11 years. METHODS: Diffusion tests were used to measure the antibiotic sensitivity of bacteria isolated from the patients with bacteremia. RESULTS: The proportion of staphylococcus epidermidis in bacteremia increased significantly. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) in bacteremia caused by staphyiococcus increased markedly. Resistance of MRSA and methlcillin-sensitive staphylococcus aureus (MSSA) to penicillin, and gentamycin increased significantly. Compared 1986-1990, with 1991-1996, the resistance of S. epidermidis to penicillin, erythromycin and methicillin increased markedly, so did resistance of pseudomonas aeruginosa to carbenicillin, and piperacillin, resistance of E. coli to gentamycin and cefoperazone, resistance of klebsiella to ampicillin and carbenicillin. The resistance of enterobacteriaceae which induced beta-lactamase to the first to the third generation of cephalosporins was relatively high. CONCLUSION: The resistance of bacteria to the commonly used antibiotics was produced in various degrees.     

Possibilities and limits of ambulatory supportive measures in oncology exemplified by antibiotic therapy of febrile neutropenia

Neutropenia is common after intensive chemotherapy. Hospitalization and intravenous broad-spectrum antibiotics are the standard of care for febrile neutropenic patients because of the risk of serious complications and associated mortality. Short neutropenic periods (< 7 days) are considered to be at a low-risk in cases when fever occurs in clinically stable patients. Recent work suggests that such a low-risk population of febrile neutropenic patients might benefit from alternatives to inpatient care. The agents that best qualify for outpatient treatment include quinolones i.v./p.o., glycopeptides, ceftriaxone and aminoglycosides, particularly if the latter are given once daily. Response rates to antimicrobial therapy range from 80 to 95% in low-risk febrile neutropenia episodes. Treating these patients in an outpatient setting avoids hospitalization in 75 to 95%. There is no doubt that outpatient therapy may have several advantages, including lower costs and an improved quality of live. Outpatient antibiotic therapy for febrile low-risk neutropenia should be considered as an acceptable alternative to inpatient treatment.     

A study of the structure and functions of the submandibular ganglion

This study examines the prevalence of coagulase-negative Staphylococcus species in normal and mildly inflamed conjunctiva, their sensitivity to antibiotics, and their relationship to the remaining flora. PATIENTS AND METHODS: In 99 patients including 9 HIV-positives in an early stage of the infection, 100 conjunctival swabs were taken and microbiologically investigated for bacteria and fungi. Thirty-four were from healthy eyes. 40 were from patients with chronic (n = 28) and unspecific (n = 12) conjunctivitis, 17 were from patients with a variety of outer inflammatory ocular conditions, and 9 were from the HIV group from uninfected (n = 6) and infected (n = 3) conjunctivae. Samples from each patient were collected with three moistened cotton swabs and directly inoculated onto five different agars, followed by immersion into three specific culture broths. Staphylococci were identified species-wise, the other microorganisms genus-wise. Sensitivity to a broad spectrum of antibiotics was determined by agar diffusion tests. OUTCOME: Staphylococci were found in 89%, which was the highest prevalence genus-wise. Of those, coagulase-negative species accounted for 86%, while coagulase-positive Staphylococcus aureus was isolated in 12% of all swabs. In the 86 smears positive for coagulase-negative staphylococci, 151 different strains were isolated. In these strains, resistance to the 13 tested antibiotics varied from 0% for vancomycin to 66% for penicillin. Strains which were isolated from patients with chronic conjunctivitis showed a greater range of resistance than those from normal flora, with significant levels for ciprofloxacin, gentamycin and kanamycin (Mann-Whitney) U-test: P < 0.05). All except six strains of staphylococci were identified strains represented ten species, of which Staphylococcus epidermidis was most prevalent (74%), but only made up 70% of all isolated strains of the coagulase-negative staphylococci. Staphylococcus aureus and gram-negative bacteria were found significantly more commonly in patients which chronic conjunctivitis than in healthy eyes, while coagulase-negative species of the Micrococcaceae family were significantly more prevalent in the healthy than in the chronically inflamed conjunctiva (chi-square: P < 0.05). CONCLUSION: The conjunctiva can simultaneously host several stems of coagulase-negative staphylococci, which differ in regard to species and resistance to antibiotics. This variety might indicate a microbiological balance of the conjunctiva and be reduced in chronic inflammatory conditions. In patients with chronic conjunctivitis the risk for multiresistant coagulase-negative staphylococci is increased.     

Randomised comparison of ceftazidime and imipenem as initial monotherapy for febrile episodes in neutropenic cancer patients

With the availability of new, broad-spectrum antibiotics, initial therapy with a single agent has become an alternative to classic combinations in the management of febrile, neutropenic cancer patients. The aims of this study were to compare the efficacy of ceftazidime and imipenem as empirical monotherapy of febrile episodes in neutropenic patients, and to examine the frequency with which second-line antibiotics (amikacin, vancomycin, or both) were required. A prospective clinical trial was carried out in a single centre. Eligible patients with solid tumours or lymphoma were randomised to receive monotherapy with ceftazidime or imipenem. In the event of no response, amikacin and/or vancomycin were added in 48-72 h intervals (sequentially, or according to clinical or microbiological data). Efficacy was evaluable for 111 assessable episodes. Median neutrophil count at entry was 100 cells/microliters and median duration of neutropenia was 4 days. Febrile episodes were classified as microbiologically (34%) or clinically documented (42%), and fever of unknown origin (24%). Gram-negative infections (57%) predominated over gram-positive isolates (30%). The overall success rate with monotherapy (69% versus 70%), or with modification (20% versus 23%) were equivalent for ceftazidime and imipenem (P = 0.75). The mortality in this series was 5%. Single-agent therapy with either ceftazidime or imipenem is effective for the empirical treatment of febrile episodes in neutropenic patients with solid tumours. Early addition of amikacin and/or vancomycin resolves most failures of the first step.     

Bacteremic pneumonia in neutropenic patients with cancer: causes, empirical antibiotic therapy, and outcome

BACKGROUND: Bacteremic pneumonia is a major cause of death among neutropenic patients with cancer. METHODS: We analyzed the causes, empirical antibiotic therapy, and outcome of 40 consecutive cases of bacteremic pneumonia identified among 408 episodes of bacteremia in adult neutropenic patients with cancer, prospectively documented from 1986 to 1995. RESULTS: The most frequent causative organisms were Pseudomonas aeruginosa (17 cases), Streptococcus pneumoniae (12 cases), Escherichia coli (5 cases), and Streptococcus mitis (3 cases). Overall, P. aeruginosa and S. pneumoniae caused 72.5% of all episodes of bacteremic pneumonia, compared with 11.4% of bacteremic episodes from other sources (P< .001). Thirty patients received ceftazidime and 10 patients received imipenem as the beta-lactam component of the initial empirical treatment. All strains of P. aeruginosa were susceptible to both agents. Forty-seven percent of streptococcal strains were penicillin resistant and showed a decreased susceptibility to ceftazidime (minimum inhibitory concentration ranged from 1 to 64 microg/mL). Five patients (12.5%) were considered to have received inappropriate empirical antibiotic therapy. Attributable mortality in patients with bacteremic pneumonia was higher than in patients with bacteremia from other sources; 22 (55%) of the 40 patients with bacteremic pneumonia died, whereas 39 (10.6%) of the 368 patients with bacteremia from other sources died (P<.001). CONCLUSIONS: Our data suggest that bacteremic pneumonia in neutropenic cancer patients is associated with a poor outcome and that empirical antibiotic therapy for neutropenic patients with pneumonia should include agents active against both P. aeruginosa and cephalosporin-resistant streptococci.     

Clinical applications of nuclear medicine in gastroenterology

This study describes the antibiotic resistance of 1961 staphylococcal strains that were isolated at the University Hospital of Vienna from July to December 1991. Staphylococcus aureus (SA) represented 43.2%; coagulase-negative (CNS) staphylococci 56.8%, three quarters of which were Staphylococcus epidermidis. Excepting netilmicin, the proportion of resistant strains to all antibiotics was higher with CNS than SA. Methicillin resistance (M(r)) was found in 11.8% of SA and 30.3% of CNS. Borderline oxacillin resistance (BOR) was noted in 7.4% of SA and 32.5% of CNS. It is important to note that severe or generalized infections due to M(r) staphylococci should be treated with glycopeptide antibiotics such as vancomycin or teicoplanin from the very beginning, whereas chemotherapy of those with BOR strains may also be carried out with beta lactamase-stable beta lactam antibiotics. Comparing the results of this study with those of the first half of 1991, the respective proportion of M(r) staphylococci was significantly lower than 23.6% for SA and 47.6% for CNS recorded then. As compared with the foregoing period, however, these strains demonstrated increased resistance frequencies to gentamicin (from 81.3 to 90%), amikacin (from 35.4 to 69%), netilmicin (35.4 to 55%), and ciprofloxacin (56.2 to 64%). This is taken as an indication for the epidemic spread of a clone of resistant strains.     

An assay to measure antibiotic efficacy against Staphylococcus epidermidis biofilms on implant surfaces

Infection is a major limitation of implantable devices. Optimal antibiotic therapeutic regimes have not yet been defined. Implant-associated infections have a number of differentiating characteristics, which include the predominance of Staphylococcus epidermidis and other skin bacteria of normally low pathogenicity as the causative agents, together with a relative resistance to host defenses and to antibiotic therapy. These properties have been ascribed to the ability of the bacteria to exist on implant surfaces in the biofilm phase, which is protective. An assay of antibiotic activity using a standardized bacterial biofilm preparation of S. epidermidis is described. The assay is used to evaluate the relative efficacy of antibiotics to sterilize the biofilm, when they are used singly, or in double or triple combinations. The modulating effects of changing antibiotic concentrations and modifying the environment with CAPD variables (fresh and spent dialysis fluid, common PD solution additives) are also measured and the data summarized. It is hoped that, by using this and similar assays, individualized optimal therapeutic regimes of implant-associated infections may be logically planned.     

The influence of (+/-)-kavain on population spikes and long-term potentiation in guinea pig hippocampal slices

The judicious use of perioperative antibiotic prophylaxis reduces the infectious complications of surgery. However, increased bacterial resistance within hospitals may make antibiotic prophylaxis less effective in the future and alternative strategies are needed. New immunomodulatory agents might prevent wound infections by stimulation of the host immune system. To test this hypothesis, we administered poly-[1-6]-beta-D-glucopyranosyl- [1-3] -beta-D-glucopyranose glucan (PGG glucan), which enhances neutrophil microbicidal activity, intravenously to guinea pigs in doses ranging from 0.015 to 4 mg/kg of body weight on the day before, on the day of, and on the day after intermuscular inoculation with methicillin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis. Abscesses were identified at 72 h, and median infective doses (ID50) and statistical significance were determined by logistic regression. Guinea pigs receiving PGG glucan and inoculated with methicillin-resistant S. aureus and S. epidermidis exhibited ID50 of as much as 2.5- and 60-fold higher, respectively, than those of control guinea pigs not receiving PGG glucan. Maximal protection was observed with a dose of 1 mg of PGG glucan per kg, and efficacy was reduced at higher as well as at lower PGG glucan doses. Furthermore, a single dose of PGG glucan given 24 h following bacterial inoculation was found to be effective in preventing infection. We conclude that PGG glucan reduces the risk of staphylococcal abscess formation. Neutrophil-activating agents are a novel means of prophylaxis against surgical infection and may be less likely than antibiotics to be affected adversely by the increasing antibiotic resistance of nosocomial pathogens.     

Interleukin 6, but not tumour necrosis factor-alpha, is a good predictor of severe infection in febrile neutropenic and non-neutropenic children with malignancy

OBJECTIVE: Interleukin-6 (IL6), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) are important mediators of the inflammatory response in human infection. The aim of this study was to determine the relationship between serum levels of IL6, TNF-alpha, IFN-gamma and CRP in febrile children with malignant disease, and relate these levels to aetiology of fever, presence of neutropenia and the effect of untreated malignancy. METHODS: 110 febrile episodes in 70 children with malignant disease were included. Cytokine analyses were performed with sensitive immunoradiometric methods using double monoclonal antibodies. RESULTS: IL6 had a sensitivity of 74% in detecting sepsis in children with fever and malignant disease. This sensitivity was not influenced by the presence of neutropenia or newly diagnosed malignancy. A positive correlation between IL6 and the CRP levels on the following day was observed (r = .53). TNF-alpha was elevated in 22% of the episodes and mean levels were significantly higher in untreated malignancy but lower in neutropenic patients. IFN-gamma was elevated in 18% of cases and correlated strongly with mean TNF-alpha levels. CONCLUSIONS: IL6 is a sensitive and early predictor of bacterial infection in both neutropenic and non-neutropenic febrile children with malignancy. It is more sensitive than CRP in detecting sepsis, but the predictive value is too low to allow IL6 levels to influence initial treatment decisions in patients with granulocytopenia. TNF-alpha production seems to be impaired in neutropenic children and serum TNF-alpha cannot be employed as an indicator of bacterial infection.     

Antimicrobial activity of fluoroquinolones and other antibiotics on 1,116 clinical gram-positive and gram-negative isolates

A total of 1,116 clinically isolated strains belonging to Staphylococcus aureus (200), Staphylococcus epidermidis (200), Streptococcus pneumoniae (20), Escherchia coli (200), Klebsiella spp. (177), Serratia marcescens (22), Pseudomonas aeruginosa (224), Haemophilus influenzae (35) and Salmonella (38) from the Department of Infectious Diseases, La Sapienza University in Rome (Italy) were tested against three fluoroquinolones (ofloxacin, ciprofloxacin and levofloxacin) and 10 other antibiotics (augmentin, ampicillin, cefaclor, cefixime, cefotaxime, cotrimoxazole, gentamicin, minocycline, oxacillin and vancomycin). Fluoroquinolones inhibited essentially about 100% of H. influenzae, Salmonella and S. pneumoniae, more than 75% of Staphylococcus including methicillin-resistant strains, and about 90% of Enterobacteriaceae and 50% of P. aeruginosa. Minimal inhibitory concentration values ranged from < 0.015 to > 32 micrograms/ml for Klebsiella, S. aureus and epidermidis, E. coli and P. aeruginosa; from < 0.015 to 2 micrograms/ml for Salmonella; from 0.03 to 16 micrograms/ml for Serratia; from < 0.015 to 1 microgram/ml for Haemophilus; and from 0.5 to 2 micrograms/ml for S. pneumoniae. Levofloxacin and to a lesser extent ofloxacin and ciprofloxacin, generally exhibited a greater activity than the other agents against both Gram-positive and Gram-negative bacteria. Regarding the distribution of resistant strains in Italy, we found a peculiar pattern of resistance as far as E. coli and P. aeruginosa were concerned. Quality control parameters are also summarized. S. epidermidis resulted as a new emergent pathogen especially in immunocompromised patients and its level of sensitivity has been modified over the last few years. In fact, the percentage of resistant strains to antibiotics or the percentage of methicillin-resistant isolates (in our study 35%), has gradually increased. Levofloxacin and ofloxacin showed good activity against staphylococcal strains compared with the majority of other antibiotics. These results suggest that the newer quinolones are promising antimicrobial agents for various infections.     

Contrast media reactions and extravasation: relationship to intravenous injection rates

Fever in neutropenic cancer patients is often due to the development of an infection. The standard management of febrile neutropenic patients involves the administration of empiric, hospital-based, parenteral antibiotic therapy. Although this treatment strategy has evolved from experience in high-risk patients with hematological malignancies, in whom bacterial infection can result in substantial morbidity and mortality, it has been adopted for all patients with febrile neutropenia, largely because of the inability of clinicians to reliably distinguish between patients who are at high risk for developing such morbidity/mortality and those who are not. The development of risk-assessment models has facilitated the recognition of high-, moderate-, and low-risk subgroups among febrile neutropenic patients and allows the administration of outpatient antibiotic therapy to the moderate- and low-risk groups, with the same degree of efficacy and safety as hospital-based therapy. Monotherapy with the carbapenems (imipenem/cilastatin and meropenem), with their broad spectrum of activity and established efficacy in high-risk patients, represents realistic options for risk-based treatment of febrile neutropenic patients within and outside the hospital setting.     

Ultrasonic enhancement of antibiotic action on gram-negative bacteria

The effect of gentamicin upon planktonic cultures of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and Staphylococcus aureus was measured with and without application of 67-kHz ultrasonic stimulation. The ultrasound was applied at levels that had no inhibitory or bactericidal activity against the bacteria. Measurements of the MIC and bactericidal activity of gentamicin against planktonic cultures of P. aeruginosa and E. coli demonstrated that simultaneous application of 67-kHz ultrasound enhanced the effectiveness of the antibiotic. A synergistic effect was observed and bacterial viability was reduced several orders of magnitude when gentamicin concentrations and ultrasonic levels which by themselves did not reduce viability were combined. As the age of the culture increased, the bacteria became more resistant to the effect of the antibiotic alone. Application of ultrasound appeared to reverse this resistance. The ultrasonic treatment-enhanced activity was evident with cultures of P. aeruginosa and E. coli but was not observed with cultures of gram-positive S. epidermidis and S. aureus. These results may have application in the treatment of bacterial biofilm infections on implant devices, which infections are usually more resistant to antibiotic therapy.     

Effect of sodium-hydrogen exchange inhibition on functional and metabolic impairment produced by oxidative stress in the isolated rat heart

PURPOSE: To determine the frequency, associate factors and clinical features of bacteremia in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP), with or without therapeutic procedures. METHODS: Prospectively, 42 consecutives patients undergoing 46 endoscopic retrograde cholangiopancreatographies (ERCPs) from August to December 1994 were analyzed. The search for bacteremia was done by drawing 6 blood samples for cultures from peripheral blood. Two blood samples were collected before the ERCP and 4 of them after. The bottles used for cultures were Bactec bottles. The bottles were incubated in the Bactec 9240 system, and eventual bacteria detect were identificated by the manual routine of the laboratory and also with the autoScan/Microscan system. RESULTS: All blood cultures obtained before the ERCPs were negatives. Bacteremia were detected after 7 endoscopic procedures. In two episodes of bacteremia, the microorganism identified (Staphylococcus epidermidis) was considered to be a contaminant. The other 5 episodes of bacteremia were considered true bacteremia (frequency- 10.9%), and the microorganisms identified were: Streptococcus viridans, Corynebacterium sp., Enterobacter cloacae, Klebsiello oxytoca and Enterobacter aerogenes. This episodes were more frequent in the blood cultures obtained immediately after the ERCPs (p < 0.05), and occurred exclusively in the patients who were not receiving antibiotics (p = 0.0192). Clinical manifestation of the episodes of bacteremia were not detected. CONCLUSION: The episodes of bacteremia occurred exclusively in the patients who were not receiving antibiotics, were transient and completely no symptomatic.     

Congenital perilymphatic fistula and associated middle ear abnormalities

An analysis of central microbial keratitis with respect to etiology, recovery, complications and visual outcome was carried out in Gothenburg, Sweden, during a 3-year period. Gram positive bacteria were found in 22 out of 48 cases; Staphylococcus aureus and Staphylococcus epidermidis accounted for more than 50% of these Gram positive cases. Pseudomonas was the most common Gram negative bacterium. No case with etiology of fungus was found. The contact lens wearers showed mainly the same bacterial spectrum as non-wearers. The initial 'shotgun' therapy with cefuroxime and gentamycin seemed adequate for this bacterial spectrum. Seventy percent of the eyes healed within 3 weeks. Contact lens wear and trauma were found to be the two major predisposing factors in the cases with microbial keratitis. The lens wearers had shorter recovery times than the non wearers. The visual results after one month were good in 50% of the eyes, and another 12% attained useful vision.