Biomedical subjects

P C Appelbaum

Publications and source records attributed to P C Appelbaum.

At least 19 recordsLinked to original sources

PubMed1992

beta-Lactamase production and susceptibility of US and European anaerobic gram-negative bacilli to beta-lactams and other agents.

The susceptibility of 1,476 US and European strains of anaerobic gram-negative bacilli to amoxicillin, amoxicillin/clavulanate, ticarcillin, ticarcillin/clavulanate, cefoxitin, imipenem and metronidazole was determined. All of the Bacteroides fragilis group and 51% of the non-Bacteroides fragilis group were beta-lactamase positive. Amongst the non-Bacteroides fragilis group, beta-lactamase positivity rates were higher for US strains (58%) than for European strains (39%). All strains were susceptible to imipenem and metronidazole. MIC90s of amoxicillin and ticarcillin for all beta-lactamase negative strains were 0.5 and 2 micrograms/ml, respectively. The addition of clavulanate reduced the MIC90s of amoxicillin (> or = 256 micrograms/ml) and ticarcillin (> or = 64 micrograms/ml) to 16 and 8 micrograms/ml, respectively, for the Bacteroides fragilis group, and to 4 micrograms/ml for both agents for the non-Bacteroides fragilis beta-lactamase producing group. Twenty-nine cefoxitin-resistant strains were found, mainly in the Bacteroides fragilis group, while 95 beta-lactamase producing strains (predominantly Bacteroides fragilis group and fusobacteria) did not show synergy between beta-lactams and clavulanate. Of the newe agents tested, meropenem and piperacillin-tazobactam were the most active (100% of strains susceptible), followed by amoxicillin-BRL 42715 (99% of strains susceptible); 94 to 98% of the strains were susceptible to cefoperazone-sulbactam, tosufloxacin, temafloxacin and clindamycin. Only 73% of the strains were susceptible to cefotetan, compared to 91% to cefoxitin; 88% of the strains were susceptible to trospectomycin. Overall, all of the beta-lactam/beta-lactamase inhibitor combinations, imipenem, meropenem, cefoxitin, tosufloxacin, temafloxacin and clindamycin had good activity against beta-lactamase producing strains, while all agents tested had good activity against beta-lactamase negative strains.

Anti-Bacterial Agents↗

PubMed1992

Evaluation of the E-Test for susceptibility testing of pneumococci.

The E-Test (AB Biodisk, Sweden) is an antibiotic gradient strip that is applied to an inoculated agar plate and results in an elliptical zone of inhibition that intercepts the graded strip, producing a quantitative (microgram per milliliter) result. Pneumococci (100) were used in this study, 38 penicillin-susceptible [minimal inhibitory concentrations (MICs), less than or equal to 0.12 micrograms/ml], 42 intermediately resistant (MICs, 0.12-1.0 micrograms/ml), and 20 resistant (MICs, greater than 1 microgram/ml). E-Test strips were evaluated on Mueller-Hinton agar plates with 5% sheep blood. Agar dilution MICs were determined by the National Committee for Clinical Laboratory Standards (NCCLS) method. Penicillin MICs for the E-Test tended to be slightly lower (one log2 dilution) than reference MICs due to the continuous scale from which E-Test MICs were read. All but two penicillin-susceptible isolates were correctly categorized by the E-Test method. Of the 62 penicillin-resistant strains, 59 had E-Test MICs of greater than or equal to 0.12 micrograms/ml, with 88% of these strains having E-Test MICs within one doubling dilution of the reference MICs. However, using the current NCCLS breakpoint MICs, many of the penicillin-resistant strains with reference MICs of 2 micrograms/ml were categorized as intermediate by the E-Test, with MICs of 0.38-1 microgram/ml. For chloramphenicol, erythromycin, and tetracycline, correlation of the two methods was excellent. E-Test chloramphenicol MICs provided clearer separation of susceptible and resistant strains than did the reference method. We conclude that the E-Test is a reliable method for determination of MICs of the antibiotics evaluated for pneumococci.

Chloramphenicol↗

PubMed1992

The presence of amniotic fluid leukoattractants accurately identifies histologic chorioamnionitis and predicts tocolytic efficacy in patients with idiopathic preterm labor.

OBJECTIVES: We tested these hypotheses: (1) that amniotic fluid from patients with idiopathic preterm labor and histologic chorioamnionitis contains leukoattractants and (2) that the detection of amniotic fluid leukoattractants is an accurate predictor of tocolytic efficacy. STUDY DESIGN: Amniotic fluid from 86 patients in idiopathic preterm labor was evaluated by microbiologic tests and leukotaxis assay. The tests' ability to predict histologic chorioamnionitis and response to tocolysis (51 tocolytic candidates) is established. Statistical analysis was performed with Fisher's exact test and unpaired Student t test. RESULTS: The detection of amniotic fluid leukoattractants was a better predictor of histologic chorioamnionitis (97%) than were amniotic fluid microbiologic tests (62%) (p less than 0.01). Also, in patients with detectable amniotic fluid leukoattractants tocolysis failed significantly more often than in patients without detectable leukoattractants (93% vs 7%, p less than 0.01). CONCLUSION: The presence of leukoattractants in amniotic fluid detected by the leukotaxis assay accurately identifies histologic chorioamnionitis and can additionally predict tocolytic efficacy in patients with idiopathic preterm labor.

Amniotic Fluid↗

PubMed1992

Hepatobiliary infections caused by Haemophilus species.

Haemophilus species are rarely associated with hepatobiliary infections. We report a case of hepatic abscess caused by Haemophilus paraphrophilus and review the English-language literature for reports of infections of the liver and biliary system caused by Haemophilus species. Most patients identified had predisposing conditions. The pathogenesis of hepatobiliary infections due to Haemophilus species may involve ascending spread from the gastrointestinal tract or hematogenous seeding following oropharyngeal colonization.

Adult↗

PubMed1992

Antimicrobial resistance in Streptococcus pneumoniae: an overview.

Clinical resistance to penicillin in Streptococcus pneumoniae was first reported by researchers in Boston in 1965; subsequently, this phenomenon was reported from Australia (1967) and South Africa (1977). Since these early reports, penicillin resistance has been encountered with increasing frequency in strains of S. pneumoniae from around the world. In South Africa strains resistant to penicillin and chloramphenicol as well as multiresistant strains have been isolated. Similar patterns of resistance have been reported from Spain. Preliminary evidence points to a high prevalence of resistant pneumococci in Hungary, other countries of Eastern Europe, and some countries in other areas of Europe, notably France. In the United States most reports of resistant pneumococci come from Alaska and the South, but resistance is increasing in other states and in Canada. Pneumococcal resistance has also been described in Zambia, Japan, Malaysia, Pakistan, Bangladesh, Chile, and Brazil; information from other African, Asian, and South American countries is not available. The rising prevalence of penicillin-resistant pneumococci worldwide mandates selective susceptibility testing and epidemiological investigations during outbreaks.

Drug Resistance, Microbial↗

PubMed1992

Susceptibilities of penicillin-susceptible and -resistant strains of Streptococcus pneumoniae to RP 59500, vancomycin, erythromycin, PD 131628, sparfloxacin, temafloxacin, win 57273, ofloxacin, and ciprofloxacin.

The MICs of four new quinolones, sparfloxacin (AT-4140, CI-978), PD 131628 (the active form of the prodrug CI-990), temafloxacin, and Win 57273, compared with those of ciprofloxacin and ofloxacin were tested against 53 penicillin-susceptible, 35 penicillin intermediate-resistant, and 51 penicillin-resistant pneumococci. Susceptibility to RP 59500, a new streptogramin, was also tested and compared with those to the quinolones, erythromycin, and vancomycin. All MICs were determined by a standardized agar dilution method by using Mueller-Hinton agar supplemented with sheep blood. Quinolone, vancomycin, and RP 59500 susceptibilities were not affected by susceptibility or resistance to penicillin. For Win 57273, the MICs for 50% (MIC50) and 90% (MIC90) of strains tested were 0.015 and 0.03 micrograms/ml, respectively. MIC50S of both sparfloxacin and PD 131628 were 0.25 micrograms/ml, and MIC90S were 0.5 micrograms/ml. The MIC50 of temafloxacin was 0.5 micrograms/ml, and the MIC90 was 1.0 micrograms/ml. By comparison, ofloxacin and ciprofloxacin both yielded MIC50S of 1.0 micrograms/ml and MIC90s of 2.0 micrograms/ml. RP 59500 yielded an MIC50 of 0.5 microgram/ml and an MIC90 of 1.0 microgram/ml and was only 1 doubling dilution less active against 17 erythromycin-resistant strains. Vancomycin was active against all strains (MIC50, 0.25 microgram/ml; MIC90, 0.5 microgram/ml). All four experimental quinolones as well as RP 59500 show promise for therapy of infections with penicillin-resistant and -susceptible pneumococci.

Anti-Infective Agents↗

PubMed1992

Susceptibilities of 540 anaerobic gram-negative bacilli to amoxicillin, amoxicillin-BRL 42715, amoxicillin-clavulanate, temafloxacin, and clindamycin.

Agar dilution MIC testing of amoxicillin, amoxicillin-BRL 42715, amoxicillin-clavulanate, temafloxacin, and clindamycin against 496 beta-lactamase-producing anaerobic gram-negative rods revealed MICs for 90% of the strains tested of 256.0 (amoxicillin), 2.0 (amoxicillin-BRL 42715 and amoxicillin-clavulanate), and 4.0 (temafloxacin and clindamycin) microgram/ml. Amoxicillin, temafloxacin, and clindamycin inhibited all 44 beta-lactamase-negative strains (MICs for 90% of the strains tested, less than or equal to 2.0 micrograms/ml). BRL 42715 will not be developed, but temafloxacin merits clinical evaluation.

Amoxicillin↗

PubMed1992

Evaluation of the 4-hour RapID NF Plus method for identification of 345 gram-negative nonfermentative rods.

The ability of the RapID NF Plus system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) to identify 345 nonfermentative gram-negative rods was evaluated. Kits were inoculated with no. 1 McFarland suspensions, and reactions were interpreted after a 4-h incubation at 35 degrees C. Overall, the method correctly identified 311 strains (90.1%) without additional tests and 21 strains (6.1%) with additional tests, and 13 strains (3.8%) were misidentified. Five of 13 misidentified strains were Alcaligenes faecalis-Alcaligenes odorans misidentified as Alcaligenes xylosoxidans; however, all strains were xylose negative but nitrate positive and could have been A. faecalis group I-Alcaligenes piechaudii. The system does not differentiate between Pseudomonas fluorescens and Pseudomonas putida, and all Acinetobacter species are identified as Acetinobacter calcoaceticus. Additionally, no subspecies differentiation is made between A. xylosoxidans subsp. xylosoxidans and A. xylosoxidans subsp. denitrificans. All strains of the former Flavobacterium group IIb are identified as Flavobacterium indologenes-Flavobacterium gleum, and no species identification of the genus Methylobacterium is attempted. The system is easy to set up and interpret and provides an accurate commercial nonautomated method for same-day identification of gram-negative nonfermenters.

Bacteriological Techniques↗

PubMed1991

Mechanisms and frequency of resistance to temafloxacin.

The bactericidal activity of temafloxacin and other fluoroquinolones is attributed to inhibition of bacterial DNA gyrase (topoisomerase II), an enzyme that regulates supercoiling and uncoiling of DNA. Because of this unique bactericidal mechanism of action, resistance to fluoroquinolones is limited to spontaneous mutations. In vitro studies were conducted to determine the frequency at which spontaneous resistance to temafloxacin occurs and to determine whether cross-resistance to other antimicrobial agents develops. In 13 strains of bacteria, the frequency of spontaneous resistance mutation to concentrations of temafloxacin at four and eight times the minimal inhibitory concentration (MIC) ranged from less than 1 x 10(-10) to 1.4 x 10(-7). Temafloxacin demonstrated a lower frequency of resistance to both methicillin-resistant and methicillin-sensitive Staphylococcus aureus compared with ciprofloxacin and ofloxacin. Cross resistance with other fluoroquinolones was observed.

Anti-Infective Agents↗

PubMed1991

Susceptibilities of 394 Bacteroides fragilis, non-B. fragilis group Bacteroides species, and Fusobacterium species to newer antimicrobial agents.

The susceptibilities of 374 selected beta-lactamase-producing gram-negative anaerobes (including 22 cefoxitin-resistant strains and 36 strains refractory to the enhancing effect of beta-lactamase inhibitors) and 20 beta-lactamase-negative strains were tested by agar dilution against selected new agents. The organisms included 217 Bacteroides fragilis group strains, 137 non-B. fragilis group Bacteroides spp., and 40 fusobacteria. All strains were susceptible to piperacillin-tazobactam, imipenem, and meropenem. For the B. fragilis group, 96% were susceptible to ampicillin-sulbactam, 95% were susceptible to amoxicillin-clavulanate and cefoperazone-sulbactam, 94% were susceptible to tosufloxacin, 91% were susceptible to cefoxitin, 88% were susceptible to trospectomycin, and 73% were susceptible to cefotetan. For the beta-lactamase-positive non-B. fragilis group Bacteroides spp., greater than or equal to 94% were susceptible to cefoxitin, amoxicillin-clavulanate, ampicillin-sulbactam, cefoperazone-sulbactam, and trospectomycin, 90% were susceptible to cefotetan, and 85% were susceptible to tosufloxacin (the most resistant strains were B. bivius and B. disiens). For the beta-lactamase-positive fusobacteria, greater than or equal to 97% were susceptible to amoxicillin-clavulanate, ampicillin-sulbactam, cefoperazone-sulbactam, trospectomycin, and cefoxitin, 90% were susceptible to cefotetan, and 89% were susceptible to tosufloxacin. All agents showed excellent activity against beta-lactamase-negative strains (for trospectomycin, 95% were susceptible; for all other drugs, 100% were susceptible). Overall, both carbapenems and piperacillin-tazobactam were most active. Amoxicillin-clavulanate, ampicillin-sulbactam, and cefoperazone-sulbactam lacked activity against some cefoxitin-resistant B. fragilis group strains but had excellent activity against other organisms. Tosufloxacin, a new quinolone, had very good activity against B. fragilis group strains (94% susceptible), good activity against other beta-lactamase-positive strains (less than or equal 85% susceptible), and excellent activity against beta-lactamase-negative strains (100% susceptible; MIC for 90% of strains, 0.5 microgram/ml). Trospectomycin was active against >90% of all strains except for B. fragilis group strains (88% susceptible; MIC for 90% of strains, 32 microgram/ml). Clinical studies are required to delineate the role of newer agents in the therapy of anaerobic infections.

Anti-Bacterial Agents↗

PubMed1990

Evaluation of two methods for rapid testing for beta-lactamase production in Bacteroides and Fusobacterium.

A total of 978 strains of Bacteroides and Fusobacterium were tested for beta-lactamase production by a disk test (Cefinase) and a microtiter nitrocefin assay. In 83% of strains both tests were positive and in 14.8% both were negative. In 1.7% of strains the disk test was positive and the microtiter test negative, and in 0.4% the disk test negative but the microtiter test positive. The disk test was less discriminatory in detecting amoxicillin-resistant strains. The microtiter test was less sensitive than the disk test, but more discriminatory if results were read within 1 h for Fusobacterium spp., within 8 h for the Bacteroides fragilis group, and within 2 h for other Bacteroides spp. Neither test should be used clinically at present.

Amoxicillin↗

PubMed1990

Susceptibility of Bacteroides non-fragilis and fusobacteria to amoxicillin, amoxicillin/clavulanate, ticarcillin, ticarcillin/clavulanate, cefoxitin, imipenem and metronidazole.

The susceptibility of 234 Bacteroides non-fragilis strains and 56 fusobacteria from 12 European centers to amoxicillin, amoxicillin/clavulanate, ticarcillin, ticarcillin/clavulanate, cefoxitin, imipenem and metronidazole was tested and related to beta-lactamase production. Beta-lactamase production was detected in 42.3 % of the Bacteroides strains and 26.8% of the fusobacteria. The MIC90 of amoxicillin for beta-lactamase-negative strains was 0.5 microgram/ml and the MIC90 of ticarcillin 2.0 micrograms/ml. In the case of beta-lactamase-positive strains the MIC90 of amoxicillin (32 micrograms/ml) and ticarcillin (16 micrograms/ml) dropped to less than or equal to 1.0 microgram/ml upon addition of clavulanate; 65.8% of these strains were susceptible to amoxicillin and 98.2% to ticarcillin, but all were susceptible when clavulanate was added. All strains were susceptible to imipenem and metronidazole, and 99.3% to cefoxitin.

Amoxicillin↗

PubMed1990

A randomized clinical study of cefoperazone and sulbactam versus gentamicin and clindamycin in the treatment of intra-abdominal infections.

This report summarizes the experience of investigators in four medical centres who compared the combination of cefoperazone/sulbactam against gentamicin/clindamycin in the treatment of intra-abdominal infections. One hundred and fifty-two patients were enrolled in the study and all were evaluable for safety and tolerance, 110 were evaluable for efficacy. Of the 76 patients (49 male, 27 female) treated with cefoperazone/sulbactam 66 (86.8%) were cured, five (6.6%) improved and five (6.6%) failed to respond to treatment. Of 34 patients treated with gentamicin/clindamycin, 21 (61.8%) were cured, four (11.8%) improved and nine (26.4%) failed. Cure rates for patients receiving cefoperazone/sulbactam were significantly higher than those of patients receiving gentamicin/clindamycin (P less than 0.006). Failures in both groups were attributable in part to pseudomonal and enterococcal infection and abscess formation. The addition of sulbactam to cefoperazone rendered cefoperazone-resistant organisms susceptible to cefoperazone in 11 of the 76 cases (14.4%) and thus permitted treatment with this agent. The present study confirms the safety and clinical efficacy of cefoperazone/sulbactam and suggests that this combination is a viable alternative to an aminoglycoside plus clindamycin for intra-abdominal infections.

Abdomen↗

PubMed1990

Beta-lactamase production, beta-lactam sensitivity and resistance to synergy with clavulanate of 737 Bacteroides fragilis group organisms from thirty-three US centres.

Beta-Lactamase production and agar dilution sensitivities to amoxycillin, amoxycillin/clavulanate, ticarcillin, ticarcillin/clavulanate, cefoxitin, imipenem and metronidazole were determined for 737 Bacteroides fragilis group strains isolated between 1986 and 1988 from 33 US centres. The strains comprised 441 B. fragilis, 114 B. thetaiotaomicron, 35 B. ovatus, 58 B. distasonis, 58 B. vulgatus, 26 B. uniformis and five B. caccae. Overall, addition of clavulanate lowered the geometric mean MICs of of amoxycillin from 46.7 to 0.6 mg/l, and of ticarcillin from 37.2 to 1.3 mg/l. Addition of clavulanate increased the number of strains sensitive to amoxycillin from 9.5% to 90.0%, and to ticarcillin from 68.0% to 98.6%. However, synergy was not observed following addition of clavulanate to amoxycillin and ticarcillin for 48 strains (6.5%). These comprised 15 B. fragilis, two B. ovatus, 21 B. distasonis, six B. vulgatus and four B. uniformis strains. Ten of the 15 non-synergic B. fragilis isolates had the features of B. fragilis homology group II and were susceptible to amoxycillin alone; the other five strains were resistant to amoxycillin and ticarcillin. Geometric mean MICs (% susceptibility) of the non-synergic strains were as follows: amoxycillin, 6.2 mg/l (68.8); amoxycillin/clavulanate, 4.8 mg/l (72.9); ticarcillin, 11.8 mg/l (75.0); ticarcillin/clavulanate, 9.4 mg/l (77.1). Twenty-six strains (3.5% were resistant (greater than 32 mg/l) to cefoxitin, and two strains (0.3%) were resistant (4 mg/l) to imipenem. All were susceptible to metronidazole. Thus, on the basis of in-vitro activity, metronidazole, imipenem, ticarcillin/clavulanate, cefoxitin and amoxycillin/clavulanate are indicated for treatment of infections with B. fragilis strains. The clinical significance of the lack of synergy with clavulanate in the B. fragilis group is unclear; relatively low beta-lactam MICs for most of these strains suggests that they may be amenable to therapy with high doses of beta-lactams. Results of this study indicate that it cannot be assumed that clavulanate will uniformly inhibit beta-lactamases in the B. fragilis group (especially B. distasonis) and indicate the need for identification and susceptibility testing, especially in cases of serious infections with these strains.

Amoxicillin↗

PubMed1990

Characterization of beta-lactamases from non-Bacteroides fragilis group Bacteroides spp. belonging to seven species and their role in beta-lactam resistance.

Twelve beta-lactamase-positive non-Bacteroides fragilis group Bacteroides spp. belonging to seven different species were examined by MIC determination and enzyme characterization. MICs of most beta-lactams except cefoxitin, cefotetan, imipenem, and meropenem were relatively high or very high. All enzymes hydrolyzed cephaloridine (Vmax, 100%; Km, 12 to 70 microM), cephalothin (Vmax, 25 to 826%; Km, 8 to 143 microM), cefamandole (Vmax, 13 to 158%; Km, 17 to 170 microM), and cefuroxime (hydrolysis rate, 19 to 98%), and 11 of 12 hydrolyzed cefotaxime (Vmax, 26 to 145%; Km, 13 to 127 microM); no hydrolysis of cefoxitin or moxalactam was observed. Penicillins were hydrolyzed at lower rates, with Vmax values less than or equal to 20% of that obtained with cephaloridine. Addition of clavulanate, sulbactam, or tazobactam led to a 4- to 2,048-fold lowering of MICs of penicillins as well as cephalosporins. All enzymes were inhibited by clavulanate (50% inhibitory concentration [IC50], 0.01 to 1.8 microM), sulbactam (IC50, 0.02 to 1.9 microM), tazobactam (IC50, 0.001 to 0.9 microM), cefoxitin (IC50, 0.002 to 0.35 microM), and moxalactam (IC50, 0.03 to 6.6 microM). No enzymes were inhibited by 100 microM EDTA or p-chloromercuribenzoic acid; an enzyme of one strain of B. loescheii was inhibited by 100 microM cloxacillin (IC50, 2.35 microM). Ten enzymes had optimal activity at pH 5.0 to 6.0, and two had optimal activity at pH 8.0. Isoelectric focusing revealed pIs between 4.2 and 5.6. These enzymes seem to belong to a previously unclassified group of beta-lactamases, related (but not identical) to beta-lactamases of the B. fragilis group.

Anti-Bacterial Agents↗

PubMed1990

Beta-lactamase production and susceptibilities to amoxicillin, amoxicillin-clavulanate, ticarcillin, ticarcillin-clavulanate, cefoxitin, imipenem, and metronidazole of 320 non-Bacteroides fragilis Bacteroides isolates and 129 fusobacteria from 28 U.S. centers.

beta-Lactamase production (nitrocefin disk method) and agar dilution susceptibility of amoxicillin, amoxicillin-clavulanate, ticarcillin, ticarcillin-clavulanate, cefoxitin, imipenem, and metronidazole were determined for 320 Bacteroides species (not Bacteroides fragilis group) and 129 fusobacteria from 28 U.S. centers. Overall, 64.7% of Bacteroides species and 41.1% of fusobacteria were beta-lactamase positive. Among the Bacteroides species, positivity rates were highest for B. bivius (85.0%), followed by B. splanchnicus (83.3%), B. eggerthii (77.8%), and B. oralis (77.1%); 54.5% of black-pigmented Bacteroides species were beta-lactamase positive. Among the fusobacteria, Fusobacterium mortiferum showed the highest rate of beta-lactamase positivity (76.9%). MICs of amoxicillin (128 micrograms/ml) and ticarcillin (64 micrograms/ml) for 90% of all beta-lactamase-positive strains were reduced to 4 and 2 micrograms/ml, respectively, with the addition of clavulanate. MICs of amoxicillin and ticarcillin for 90% of all beta-lactamase-negative strains were 1 and 4 micrograms/ml, respectively, and greater than or equal to 98.4% of the strains were susceptible to the beta-lactams tested. Of the beta-lactamase-producing strains, 45.9% were susceptible to amoxicillin at less than or equal to 4 micrograms/ml and 93.4% were susceptible to ticarcillin at less than or equal to 64 micrograms/ml; the addition of clavulanate raised the rates to 90.4 and 100%, respectively. All strains were susceptible to cefoxitin, imipenem, and metronidazole. The activity of amoxicillin against 29 beta-lactamase-producing strains (10 Bacteroides species and 19 fusobacteria) was not enhanced by the addition of clavulanate; however, 82.7% of these strains were susceptible to amoxicillin, and all were susceptible to ticarcillin. Although beta-lactamase positivity is on the increase in non-B. fragilis group Bacteroides species and fusobacteria, amoxicillin-clavulanate, ticarcillin, cefoxitin, imipenem, and metronidazole should be suitable for the treatment of infections with these strains. The addition of clavulanate does not appreciably improve the efficacy of ticarcillin against these organisms.

Amoxicillin↗

PubMed1989

Amniotic fluid leukotaxis assay as an early indicator of chorioamnionitis.

A characteristic feature of histologic chorioamnionitis caused by ascending infection is the amniotropism displayed by polymorphonuclear leukocytes in the placental membranes. We tested the hypothesis that amniotic fluid from patients with histologic chorioamnionitis and intact membranes without clinical infection contains leukoattractants detectable by an in vitro leukotactic assay. Leukoattractants were detected in 13 cases (87%) and absent in 2 cases (13%) with histologic chorioamnionitis (p less than 0.005). The two cases with histologic chorioamnionitis that had negative leukotaxis were classified as stage l/mild severity. A positive leukotactic response was a better predictor of histologic chorioamnionitis (87%) than positive Gram stain (33%), amniotic fluid culture (53%), gas-liquid chromatography (40%), or a combination of these three methods (60%). These results suggest that demonstration of leukoattractants in amniotic fluid is an earlier and more sensitive predictor of chorioamnionitis than is presently available.

Amniotic Fluid↗

PubMed1989

Vascular prosthetic infection with Staphylococcus epidermidis: experimental study of pathogenesis and therapy.

To determine whether a slime-producing strain of Staphylococcus epidermidis was capable of producing acute infection of a prosthetic vascular graft, 5 cm segments of knitted Dacron were implanted in the infrarenal aortic position of dogs in three groups of animals. These included a control group (no graft contamination), a contaminated group that received a graft soaked in an S. epidermidis solution (untreated group), and a contaminated group in which perioperative antibiotics (three doses of cefamandole, 100 mg/kg) were administered (prophylaxis group). In all the animals reexploration and graft removal were performed at 10 days, with replacement of the defect being achieved with a new uncontaminated graft. These animals underwent exploration a third time after an additional 10-day period. S. epidermidis was not grown from the control animals (n = 7) but was cultured in 44% of the prophylaxis group (n = 9) and 88% of the untreated group (n = 16) during at least one of the operative procedures (chi 2 = 15.859; p less than 0.001). The pathologic features of acute S. epidermidis infection were best seen in the untreated animals and included anastomotic disruption (56%), periaortic hematoma, and lymphadenopathy (94%). Microscopic examination of the aortic tissues revealed extensive infiltrates of leukocytes, macrophages, and foreign body giant cells with aortic necrosis. These features were less prominent in the prophylaxis animals. We conclude that S. epidermidis is capable of producing acute graft infection with perigraft inflammation and anastomotic disruption. The administration of perioperative antibiotics reduced but did not abolish these effects of bacterial contamination of prosthetic vascular grafts.

Animals↗