Showing papers on "Penicillin published in 1982"
TL;DR: Vancomycin is effective but potentially toxic therapy for most serious infections due to methicillin-resistant S. aureus and in-vitro tests may not predict therapeutic efficacy.
Abstract: Ten patients with bacteremia due to methicillin-resistant Staphylococcus aureus were treated with vancomycin. These patients were compared with matched controls, nine bacteremic patients with methicillin-sensitive S. aureus, and one patient with penicillin-sensitive S. aureus. Controls were treated with a penicillin. There were no significant differences in time to defervescence, metastatic infections, relapse, mortality, need for surgical drainage, or duration of therapy. Fifteen of 19 episodes of serious methicillin-resistant S. aureus infection responded to vancomycin. Severe toxic effects included tinnitus, neutropenia, rash, and possible nephrotoxicity. Tolerance (a minimal bactericidal concentration to minimal inhibitory concentration ratio of at least 32), but not a minimal bactericidal concentration of at least 32 mg/L, correlated with therapeutic failure (respectively, p = 0.04 and p = 0.11, Fisher's exact test). Bacteremic infections due to methicillin-resistant and methicillin-sensitive S. aureus cause similar morbidity and mortality. Vancomycin is effective but potentially toxic therapy for most serious infections due to methicillin-resistant S. aureus. In-vitro tests may not predict therapeutic efficacy.
262 citations
227 citations
TL;DR: The purified penicillin beta-lactamase gave a single protein band on polyacrylamide gel electrophoresis, and showed a unique substrate profile, hydrolyzing N-formimidoyl thienamycin at a significant rate.
Abstract: Two types of beta-lactamase were found in the cell-free extract from Pseudomonas maltophilia GN12873. One was an inducible penicillin beta-lactamase, and the other was an inducible cephalosporin beta-lactamase. The purified penicillin beta-lactamase gave a single protein band on polyacrylamide gel electrophoresis. The isoelectric point was 6.9, and the approximate molecular weight was 118,000 by gel filtration and 26,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting that this enzyme consisted of four subunits. For the hydrolysis of penicillin G, the optimal pH was 8.0 and the optimal temperature was 35 degrees C. The enzyme activity was inhibited by cephamycin derivatives, carpetimycins A and B, iodine, and HgCl2, but not by clavulanic acid. Furthermore, beta-lactamase activity was almost completely inhibited by EDTA but was recovered by the addition of zinc ion. The enzyme showed a unique substrate profile, hydrolyzing N-formimidoyl thienamycin at a significant rate.
226 citations
TL;DR: It is concluded that the risk of subsequent allergic reactivity to penicillin is much lower if the skin tests are negative than if positive, that testing with semisynthetic penicillins increases the number of skin-test reactors, and that the incidence of allergic reactions is low in patients treated with cephalosporin.
Abstract: From 1971 through August 1978, 778 patients underwent penicillin skin testing. Each patient gave a history of previous penicillin allergy. The skin-test reagents consisted of (1) fresh solutions of commercially prepared penicillin G (PEN G), ampicillin (AMP), and methicillin (METH); (2) polylysine conjugates of the major antigenic determinants of each of the three drugs; and (3) alkaline hydrolysates of each drug. A total of 108 (14%) patients showed positive reactions to one or more of the reagents. Certain patients showed reactivity to many reagents, whereas others reacted selectively to only one or two reagents. Addition of reagents of AMP and METH resulted in a greater number of positive reactors than when reagents of PEN G alone were used. Of the group whose skin tests were negative, 290 (43%) were later treated with a penicillin, twelve of these (4.1%) had allergic reactions. Eight of the group whose skin tests were positive were subsequently treated, and four of these (50%) had allergic reactions again. A group of 151 patients whose skin tests were negative and 27 patients whose skin tests were positive were treated with a cephalosporin. Only two patients had allergic reactions to the drug; both had had negative skin tests to penicillin. We conclude that the risk of subsequent allergic reactivity to penicillin is much lower if the skin tests are negative than if positive, that testing with semisynthetic penicillins increases the number of skin-test reactors, and that the incidence of allergic reactions is low in patients treated with a cephalosporin.
192 citations
TL;DR: High susceptibility to penicillin was shown by an organism that did not have detectable muramic acid in preparations of either whole cells or sodium dodecyl sulfate-insoluble residues.
Abstract: Chlamydia trachomatis LGV-434 was grown in HeLa 229 cells. Benzylpenicillin completely inhibited the formation of infectious elementary bodies (EBs) at a concentration of 19 pmol/ml or higher and produced abnormally large reticulate bodies (RBs) in the inclusions at 30 pmol/ml or higher. The possible targets for penicillin in C. trachomatis were three penicillin-binding proteins (PBPs) which were identified in the Sarkosyl-soluble fractions of both RBs and EBs. The apparent subunit molecular weights were 88,000 (PBP 1), 61,000 (BPB 2), and 36,000 (PBP 3). The 50% binding concentrations of [3H]penicillin for PBPs 1 to 3 in EBs and RBs were between 7 and 70 pmol/ml. Such high susceptibility to penicillin was shown by an organism that did not have detectable muramic acid (less than 0.02% by weight) in preparations of either whole cells or sodium dodecyl sulfate-insoluble residues.
167 citations
TL;DR: The results of this study suggest that oral desensitization is an effective, relatively safe approach to administering beta-lactam antibiotics to penicillin-allergic patients with life-threatening infections.
Abstract: When patients allergic to penicillin develop life-endangering infections that require treatment with beta-lactam antibiotics, they face a fatal infection or the possibility of a fatal allergic reaction. We have approached this situation by using an oral desensitization procedure before full-dose antibiotic therapy. Thirty consecutive patients with histories of allergic reactions to penicillin, positive immediate wheal and flare skin-test reactions to penicillin determinants, and life-threatening infections were studied. Bacterial endocarditis requiring penicillin G therapy led to desensitization of 19 patients, Pseudomonas sepsis of pneumonia requiring treatment led to desensitization of nine subjects, and staphylococcal infections requiring therapy with a penicillinase-resistant penicillin led to desensitization of two patients. Penicillin G or carbenicillin were administered orally, beginning with 100 U or 60 microgram, respectively. At 15-min intervals, progressively doubled doses were given during continuous monitoring for the appearance of allergic reactions. Within 5 hr, full therapeutic doses were administered intravenously. Skin-test reactions disappeared or diminished in all 23 subjects who were retested after desensitization. Full courses of antibiotic therapy and cure of the infections were accomplished in 30 of 30 patients. No deaths, anaphylaxis, or severe acute allergic reactions occurred. Pruritic cutaneous eruptions appeared in nine patients (30%) 6 to 48 hr after the onset of therapy. One patient developed reversible nephritis 3 wk into therapy with penicillin G. The results of this study suggest that oral desensitization is an effective, relatively safe approach to administering beta-lactam antibiotics to penicillin-allergic patients with life-threatening infections.
136 citations
TL;DR: The addition of an aminoglycoside to penicillin, ampicillin, vancomycin or piperacillin--which are not bactericidal against most strains of enterococci--results in more rapid and complete bacterial activity (ie, synergistic activity).
Abstract: • Enterococci cause urinary tract infection (usually asymptomatic), 5% to 15% of cases of endocarditis, and rare cases of meningitis. Their role in polymicrobial infection in the abdomen and pelvis is difficult to assess. Ninety percent of enterococci are inhibited by 4 mg/L of penicillin G, by 2 mg/L of ampicillin, and by 6 mg/L of vancomycin. The penicillinase-resistant penicillins, cephalosporins, carbenicillin, and ticarcillin are at least fourfold less active against enterococci than penicillin G, whereas piperacillin has activity equivalent to penicillin G. The addition of an aminoglycoside to penicillin, ampicillin, vancomycin or piperacillin—which are not bactericidal against most strains of enterococci—results in more rapid and complete bactericidal activity (ie, synergistic activity). ( Arch Intern Med 1982;142:2006-2009)
130 citations
TL;DR: The penicillin-binding proteins of a clinical isolate of Staphylococcus aureus specifically resistant to oral cephalosporins were compared with those of a susceptible strain, and the results are consistent with the suggestion that PBP2 is essential in S. aUREus.
Abstract: The penicillin-binding proteins (PBPs) of a clinical isolate of Staphylococcus aureus specifically resistant to oral cephalosporins were compared with those of a susceptible strain. In the resistant strain, PBP3 (75,000 molecular weight) was missing or had substantially (greater than 100-fold) reduced affinity for penicillin; PBP2 (80,000 molecular weight) was increased in amount and contained a satellite band, PBP2'; PBPs 1 and 4 were unchanged. Oral cephalosporins bound poorly to PBP2 in both susceptible and resistant strains, but only in the latter did binding correlate with antibiotic activity. The results are consistent with the suggestion that PBP2 is essential in S. aureus. PBP2 might in addition compensate for PBP3 when the latter is missing. In the susceptible strain the lack of correlation between binding to PBP2 and beta-lactam antibiotic activity is due to the very high affinity of the also essential PBP3 for beta-lactam antibiotics.
110 citations
TL;DR: Three penicillin-allergic patients with life-endangering infections requiring beta-lactam antibiotic therapy were desensitized by means of increasing oral then parenteral doses and were treated with full doses of beta- lactam agents, associated with antigen-specific desensitization of tissue mast cells.
Abstract: Three penicillin-allergic patients with life-endangering infections requiring beta-lactam antibiotic therapy were desensitized by means of increasing oral then parenteral doses and were treated with full doses of beta-lactam agents. Malignant otitis externa caused by Pseudomonas aeruginosa, osteomyelitis caused by Staphylococcus aureus, and bacterial endocarditis caused by an enterococcus were treated with carbenicillin, nafcillin, and benzylpenicillin G, respectively. No acute allergic reactions occurred during desensitization or within 1 wk of the onset of therapy. Immediate wheal and flare skin-test reactions to beta-lactam determinants diminished or became negative after the desensitization procedure in each patient. Wheal and flare responses provoked by histamine, compound 48/80, and environmental antigens were not affected by the desensitization procedure or continued beta-lactam drug therapy. Mild urticaria appeared after 15 days of penicillin therapy in one patient and after 23 days of carbenicillin therapy in another patient. Skin-test reactions to penicillin reagents had reverted to positive at the time of the urticarial reactions. One patient developed a severe immune hemolytic anemia after 10 days of therapy with nafcillin. The results of this study indicate that acute clinical desensitization of these three penicillin-allergic patients was associated with antigen-specific desensitization of tissue mast cells.
106 citations
TL;DR: It is suggested that the emergency of antibiotic resistance in S. Aureus may result from genetic transfer from S. epidermidis as well as from the interhospital spread of resistant staphylococci.
Abstract: During a 7-month period in 1978 to 1979, 31 patients and personnel at a Kentucky hospital were colonized or infected with a Staphylococcus aureus strain resistant to clindamycin, erythromycin, gentamicin, methicillin, penicillin, and tetracycline. S. epidermidis with similar antibiotic resistance patterns had been isolated in this hospital in the year before the S. aureus outbreak. A 32-megadalton R-plasmid, pUW3626, mediating resistance to penicillin and gentamicin, was present in these isolates and in coisolated S. epidermidis from the same outbreak. By colony hybridization, pUW3626 was homologous to gentamicin R-plasmids from staphylococci isolated in other geographic areas. Our studies suggest that the emergency of antibiotic resistance in S. Aureus may result from genetic transfer from S. epidermidis as well as from the interhospital spread of resistant staphylococci.
98 citations
TL;DR: Three new broad-spectrum penicillins--azlocillin, mezLocillin, and piperacillin--will soon be available for clinical use and appear to be relatively safe and have been used successfully to treat patients with various infections; however, comparative trials have not yet established the superiority of these drugs over conventional therapeutic agents.
Abstract: Three new broad-spectrum penicillins--azlocillin, mezlocillin, and piperacillin--will soon be available for clinical use. Azlocillin and piperacillin are more active than carbenicillin or ticarcillin against Pseudomonas aeruginosa. Piperacillin and mezlocillin demonstrate significant activity against the Enterobacteriaceae, including many strains of Klebsiella pneumoniae against which the older penicillins carbenicillin, ticarcillin, and ampicillin are ineffective. All three new drugs show substantial activity against anaerobes and ampicillin-susceptible gonococci and Haemophilus influenzae. Because these agents are inactivated by various beta-lactamases, most Staphylococcus aureus isolates and a number of gram-negative organisms, including some important nosocomial pathogens, will be resistant to these antibiotics. The new penicillins appear to be relatively safe and have been used successfully to treat patients with various infections; however, comparative trials have not yet established the superiority of these drugs over conventional therapeutic agents.
TL;DR: The efficacy of a single dose of aqueous penicillin G in preventing neonatal group-B streptococcal infections was demonstrated in a randomised study conducted over 41 months.
TL;DR: The results suggest that penicillin G combined with an aminoglycoside can be recommended for the treatment of subacute endocarditis caused by Gemella haemolysans.
Abstract: Gemella haemolysans, a member of the family Streptococcacae, was isolated from patients with subacute endocarditis. The minimal inhibitory concentrations of 21 antimicrobial agents for five strains of the organism were determined. All strains were highly sensitive to penicillin G and ampicillin. Cefotaxime was the most active cephalosporin tested. All strains were sensitive to vancomycin, chloramphenicol and rifampin. Four strains were sensitive to tetracycline and erythromycin. All strains demonstrated a low level of resistance to aminoglycosides and were highly resistant to sulfonamides and trimethoprim. Killing curves and checker-board titration demonstrated synergism between penicillin G and streptomycin or gentamicin, and also between vancomycin and streptomycin or gentamicin. The results suggest that penicillin G combined with an aminoglycoside can be recommended for the treatment of subacute endocarditis caused by Gemella haemolysans.
TL;DR: These findings constitute direct observation of the interaction of beta-lactams with a transpeptidase enzyme and establish the feasibility of defining the molecular stereochemistry of this interaction for purposes of drug design.
Abstract: The three-dimensional structure of a penicillin-sensitive D-alanyl-carboxypeptidase-transpeptidase has been determined by x-ray crystallography to a resolution of 2.8 angstroms. The site of binding of the beta-lactam antibiotics penicillin and cephalosporin has been located. These findings constitute direct observation of the interaction of beta-lactams with a transpeptidase enzyme and establish the feasibility of defining the molecular stereochemistry of this interaction for purposes of drug design.
TL;DR: This study examined the resistance to penicillin, tetracycline, erythromycin, and chloramphenicol of 318 pneumococcal strains isolated in Spanish hospitals from blood or cerebrospinal fluid of patients during 1979 to 1981 to discover whether a correlation between serotype and patterns of antibiotic resistance could be found.
Abstract: This study examined the resistance to penicillin, tetracycline, erythromycin, and chloramphenicol of 318 pneumococcal strains isolated in Spanish hospitals from blood or cerebrospinal fluid of patients during 1979 to 1981. The serotypes of these strains were determined to discover whether a correlation between serotype and patterns of antibiotic resistance could be found. Seven and nine patterns of resistance were found in strains isolated from blood and cerebrospinal fluid, respectively; tetracycline was the most frequent pattern, followed by tetracycline associated with chloramphenicol. A random distribution of serotypes which was similar to the general distribution of serotypes was found for resistance to tetracycline and chloramphenicol, but penicillin-resistant strains were confined to seven serotypes. Thirty-six strains of penicillin-resistant pneumococci isolated from sources other than blood or cerebrospinal fluid were also serotyped. They represented the same serotypes, suggesting that serotype distribution among penicillin-resistant strains could be a manifestation of local epidemiological factors.
TL;DR: Application of the simple and powerful technique of sodium dodecyl sulphate electrophoresis for the identification of bacterial membrane components--penicillin binding proteins--that bind radioactive penicillin and most likely represent the primary biochemical targets of Penicillin action in the bacterial cell has led to a remarkable number of novel observations.
Abstract: The last 5 to 6 years have witnessed an outburst of renewed interest in the beta-lactam antibiotics. One of the main factors contributing to this was the introduction of the simple and powerful technique of sodium dodecyl sulphate electrophoresis for the identification of bacterial membrane components--penicillin binding proteins--that bind radioactive penicillin and most likely represent the primary biochemical targets of penicillin action in the bacterial cell. Application of this technique has led to a remarkable number of novel observations that have substantially modified our view of the mode of action of beta-lactam antibiotics.
TL;DR: In this paper, the authors proposed a method to improve the quality of the data collected by the data collection system, which can be found in Table 1.1.1].
Abstract: ImagesFigure 1Figure 2Figure 3Figure 4
01 Dec 1982
TL;DR: There appears to be a striking increase in penicillin resistance by the "non-fragilis" Bacteroides, and whether this represents a true increase in resistance will require close scrutiny of clindamycin susceptibility in the future.
Abstract: Results of antimicrobial susceptibility testing of anaerobes were reviewed for the last 5 years and compared with two previous surveys from this institution. Allowing for differences in methodology, there appears to be a striking increase in penicillin resistance by the "non-fragilis" Bacteroides. Penicillin concentrations of 50 microgram/ml were required to inhibit 70% of 43 strains tested. The clinical implications of this observation are not known, but isolated reports of therapeutic failure when penicillin was used against the non-fragilis Bacteroides have appeared. Penicillin resistance among Clostridium other than C. perfringens was also noted in the current study. Several strains of clindamycin-resistant Bacteroides fragilis have been observed during the last 2 years, and whether this represents a true increase in resistance will require close scrutiny of clindamycin susceptibility in the future. Future surveillance of antimicrobial susceptibility of anaerobic bacteria will be useful in the detection of any major changes in susceptibility profiles. This knowledge will potentially affect the choice of antimicrobial agent in patients with serious infections caused by anaerobes.
TL;DR: Patterns of resistance were complex and may be useful as an accessory typing system for Staphylococcus epidermidis strains received in the years 1978, 1979 and 1980 and compared with that of strains collected for an international study.
Abstract: Summary
Resistance to 11 antimicrobial drugs was assessed in 532 clinically significant strains of Staphylococcus epidermidis received in the years 1978, 1979 and 1980 and compared with that of strains collected in 1976 and 1977 for an international study. Only 14% of strains were sensitive to all the drugs tested. Resistance to gentamicin increased significantly from 7% to 33% during the study period. The degree of association between pairs of drugs was assessed. There was strong association between resistance to methicillin, aminoglycosides and macrolide antibiotics and only weak association between resistance to novobiocin, tetracycline, chloramphenicol and penicillin. Patterns of resistance were complex and may be useful as an accessory typing system.
TL;DR: Clinical experience dictates that ampicillin or penicillin should remain the antibiotic of choice in the treatment of severe infections, such as meningitis caused by L. monocytogenes, but further in vitro and vivo studies are needed before therapy with rifampin or TMP-SMX in combination with penicillins can be recommended.
Abstract: Antibiotic susceptibility and synergy were studied in 12 clinical isolates of Listeria monocytogenes from patients with meningitis and septicemia Rifampin and trimethoprim-sulfamethoxazole (TMP-SMX) were the most potent single drugs tested Approximately 80% of the strains demonstrated full synergistic bactericidal activity with rifampin in combination with penicillin or ampicillin Clinical experience dictates that ampicillin or penicillin should remain the antibiotic of choice in the treatment of severe infections, such as meningitis caused by L monocytogenes Where the use of penicillin is contraindicated (eg, allergy or failure to respond), use of TMP-SMX might be considered Further in vitro and vivo studies are needed before therapy with rifampin or TMP-SMX in combination with penicillin or ampicillin can be recommended
TL;DR: It is concluded that the routine administration of prophylactic penicillin neither protects against cellulitis and burn wound sepsis, nor promotes selection of antibiotic-resistant bacteria in hospitalized patients with acute thermal injury.
Abstract: The use of prophylactic low-dose penicillin acutely burned, hospitalized patients remains controversial. Fifty-one adult patients with burns of 1% to 91% total body surface area were prospectively studied to determine the efficacy of prophylactic penicillin in the prevention of wound cellulitis and burn wound sepsis, and to examine the influence of prophylactic penicillin on the emergence of antibiotic resistant microorganisms. In 25 patients given a 5-day course of penicillin prophylactically, 11 developed cellulitis and two had burn wound sepsis. A similar group of patients given placebo developed seven cases of cellulitis and three cases of burn wound sepsis (p = 0.340). No patient in either group developed gentamicin-resistant Gram-negative organisms, although the gastrointestinal tracts of two patients in the penicillin group showed new colonization by yeast. We conclude that the routine administration of prophylactic penicillin neither protects against cellulitis and burn wound sepsis, nor promotes selection of antibiotic-resistant bacteria in hospitalized patients with acute thermal injury.
TL;DR: High in-vitro resistance was found for penicillinase-producing Neisseria gonorrhoeae and six of eight other antimicrobial agents tested, reflecting the difficulties encountered in selecting therapeutic agents for the control of gonor rhoea in Thailand.
TL;DR: Penicillin-resistant and peniillin-tolerant mutants have been isolated from group A streptococci mutagenized by ethyl methane sulfonate and had virtually unchanged minimal inhibitory concentration values for penicillin and normal cellular morphology and pencillin-binding proteins.
Abstract: Penicillin-resistant and penicillin-tolerant mutants have been isolated from group A streptococci mutagenized by ethyl methane sulfonate. The resistant mutants had an elevated minimal growth inhibitory concentration for benzylpenicillin (minimal inhibitory concentration, 0.2 microgram/ml, as compared with the minimal inhibitory concentration of 0.006 microgram/ml in the penicillin-susceptible parent strain); they also had an abnormal cellular morphology and showed altered penicillin-binding proteins. Penicillin-tolerant mutants were killed more slowly than were the parental cells during treatment with penicillin; they had virtually unchanged minimal inhibitory concentration values for penicillin and normal cellular morphology and penicillin-binding proteins.
TL;DR: Over 90% of the Staphylococcus isolates were easily identified as to their species on the basis of their reaction profile to 19 biochemical tests included in the kit, and general resistance to sulfamethoxazole and nalidixic acid was found among all strains, with almost uniform sensitivity to the other drugs tested.
Abstract: A kit for the identification of staphylococci based on the biochemical criteria proposed by Kloos and Schleifer (W.E. Kloos and K.H. Schleifer, J. Clin. Microbiol., 1:82-88, 1975) is now available commercially. The system was used to identify 100 strains of coagulase-negative staphylococci isolated from various body sites as the primary etiological agent of clinical infection. The increasing importance of staphylococci and their resistance to antibiotics provided the rationale for such an investigation. Over 90% of the Staphylococcus isolates were easily identified as to their species on the basis of their reaction profile to 19 biochemical tests included in the kit. The remainder, which showed minor variations, could also be assigned to the various species. Identification of the isolates was as follows: S. epidermidis, 54; S. haemolyticus, 5; S. simulans, 2; S. hominis, 1; S. capitis, 4; S. cohnii, 2; S. warneri, 2; S. xylosus, 8; and S. saprophyticus, 22. Antibiotic sensitivity patterns were determined for each of the isolates. Novobiocin resistance was detected in strains of S. saprophyticus and S. xylosus, a property hitherto recognized in Micrococcus sp. type 3 causing bacteriuria in young women. Resistance to penicillin was widespread among strains of several species, whereas resistance to tetracycline was mainly confined to strains of S. epidermidis. General resistance to sulfamethoxazole and nalidixic acid was found among all strains, with almost uniform sensitivity to the other drugs tested.
TL;DR: Penicillin solutions should be freshly prepared and administered from vials containing less than 10 million IU so that bolus doses can be given and causative antigens seem to be related to penicilloylated high molecular weight impurities in the penicillin preparations.
TL;DR: Transmission and scanning electron microscopy studies of testicular aspirates obtained from rabbits treated with ceftriaxone revealed alterations in the treponeme surface which apparently resulted in changes in cell permeability and morphology.
Abstract: The activity of ceftriaxone, a newly developed cephalosporin, against early cutaneous infections with Treponema pallidum in rabbits was compared with that of equimolar doses of penicillin G. Activity was related to the time required for cutaneous lesions to become dark-field negative, serological response, and the disappearance of T. pallidum from the popliteal lymph nodes. Both antibiotics were very effective in the treatment of syphilis in this animal model. The 50% curative dose for penicillin G was 0.8 mumol/kg (0.29 mg or 480 U/kg) and for ceftriaxone, it was 1.45 mumol/kg (0.96 mg/kg). Overall, ceftriaxone was slightly less effective than penicillin G was. Transmission and scanning electron microscopy studies of testicular aspirates obtained from rabbits treated with ceftriaxone revealed alterations in the treponeme surface which apparently resulted in changes in cell permeability and morphology.
TL;DR: It is indicated that both intravenous and oral penicillin G prophylaxis for dental extractions decreased bacteremia rates significantly, including the recovery of streptococci.
TL;DR: Rifampin, penicillin, clindamycin, and erythromycin were the most active antibiotics tested with minimal bactericidal concentrations for 90% of the strains and corresponding values for vancomycin and streptomycin were 32 and 16 microgram/ml, respectively.
Abstract: Seventeen strains of nutritionally variant streptococci were examined for susceptibility to 15 antimicrobial agents. All strains grew in blood culture medium containing blood and blood products or, in the absence of blood or blood products, in broth containing glucose and pyridoxal hydrochloride. Growth was enhanced by incubation in an atmosphere containing 5%-10% CO2 or, in some cases, was CO2-dependent. Rifampin, penicillin, clindamycin, and erythromycin were the most active antibiotics tested with minimal bactericidal concentrations of 2, 1, 2, and 2 microgram/ml, respectively, for 90% of the strains; the corresponding values for vancomycin and streptomycin were 32 and 16 microgram/ml, respectively.
TL;DR: A highlyPenicillin-resistant strain of Bacteroides fragilis, strain GN11499, was found among 80 clinical isolates of the B.fragilis group and appears to produce a new type of penicillinase, which hydrolyzed ampicillin and cloxacillin more rapidly than it didpenicillin G, carbenicillin, and cephaloridine.
Abstract: A highly penicillin-resistant strain of Bacteroides fragilis, strain GN11499, was found among 80 clinical isolates of the B.fragilis group and appears to produce a new type of penicillinase. Penicillinase activity was detected in crude extracts and had a specific activity of 0.25 U/mg of protein. About 20% of the enzyme was released into the surrounding medium during growth. The enzyme hydrolyzed ampicillin and cloxacillin more rapidly than it did penicillin G, carbenicillin, and cephaloridine. Relative rates in a crude extract with penicillin G as 100 were ampicillin, 357; carbenicillin, 57; cloxacillin, 271; and cephaloridine, 71. Enzyme activity was inhibited by clavulanic acid, CP-45, 899, N-formimidoyl thienamycin, cefoxitin, moxalactam, and p-chloromercuribenzoate. The enzyme had a molecular weight of approximately 41,500 and an isoelectric point of 6.9. Penicillinase production and tetracycline resistance were transferred from B.fragilis GN11499 to two susceptible strains of B.fragilis and Bacteroides vulgatus by filter mating.
TL;DR: Data suggest that classical endotoxin is not the cause of the Jarisch-Herxheimer reaction, and rabbits were not refractory to the pyrogenic effects of endotoxin, and syphilitic rabbits rendered tolerant to endotoxin still developed fever when treated with penicillin.
Abstract: The etiology of the Jarisch-Herxheimer reaction is unknown, but the reaction may result from toxic products of dead or dying treponemes reacting with sensitized syphilitic tissues. Because of similarities of spirochetes with gram-negative bacteria, endotoxin has been proposed as the responsible toxin. In 19 patients with syphilis, a reaction occurred in 15 (79%) during treatment with penicillin. Endotoxemia was not found by the limulus amoebocyte lysate test. All animal model of the Jarisch-Herxheimer reaction was developed in rabbits infected with Treponema pallidum. When treated with penicillin, 18 (78%) of 23 rabbits infected 18-29 days previously developed a reaction that resembled that in humans. Endotoxemia was not detected by the lysate test. After the reaction, rabbits were not refractory to the pyrogenic effects of endotoxin, and syphilitic rabbits rendered tolerant to endotoxin still developed fever when treated with penicillin. These data suggest that classical endotoxin is not the cause of the Jarisch-Herxheimer reaction.