Using CHROMagar™ STEC medium exclusively does not recover all clinically relevant Shiga toxin-producing Escherichia coli in Aotearoa, New Zealand

Diagnostic laboratories in Aotearoa, New Zealand (NZ) refer cultures from faecal samples positive for Shiga toxin genes to the national Enteric Reference Laboratory for isolation of Shiga toxin-producing Escherichia coli (STEC) for epidemiological typing. As there was variation in the culture media being referred, a panel of 75 clinical isolates of STEC, representing 28 different serotypes, was used to assess six commercially available media and provide guidance to clinical laboratories. Recommendations were subsequently tested for a 3-month period, where STEC isolations and confirmations were assessed by whole genome sequencing analysis against the culture media referred. CHROMagar™ STEC (CH-STEC; CHROMagar Microbiology, Paris, France) or CH-STEC plus cefixime-tellurite sorbitol MacConkey agar was confirmed inferior to CH-STEC plus blood agar with vancomycin, cefsulodin, and cefixime (BVCC). The former resulted in fewer STEC types (n = 18) being confirmed compared to those from a combination of CH-STEC and BVCC (n = 42). A significant (P < .05) association with an STEC's ability to grow on CH-STEC and the presence of the ter gene cluster, and eae was observed. Culturing screen positive STEC samples onto both CH-STEC and BVCC ensures a consistently higher recovery of STEC from all clinical samples in NZ than CH-STEC alone.

A comparison of two pre-enrichment media prior to immunomagnetic separation for the isolation of E. coli O157 from bovine faeces

AIMS

To compare the sensitivity of two pre-enrichment broth media prior to immunomagnetic separation for the isolation of Escherichia coli O157 from cattle faeces.

METHODS AND RESULTS

One-gram portions of 721 cattle faeces collected from 43 farms were pre-enriched in buffered peptone water containing vancomycin, cefixime and cefsulodin (BPW-VCC) and buffered peptone water without additives (BPW-WOA), respectively. A total of 137 samples were positive for E. coli O157: 127 pre-enriched with BPW-WOA and 89 pre-enriched in BPW-VCC. Representative isolates were tested for phage type, verotoxin and eae (E. coli attaching and effacing) gene sequences, resulting in the recognition of eight different types. All the E. coli O157 types recognized were isolated by both methods except for three different strains, each of which were isolated only on a single occasion: two by BPW-WOA and another by BPW-VCC.

CONCLUSIONS

The results clearly demonstrate, under the conditions of this study, that BPW without antibiotics was the superior pre-enrichment medium for the isolation of E. coli O157 from cattle faeces.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of BPW-WOA in preference to BPW-VCC for the isolation of E. coli O157 from cattle faeces in future research and outbreak studies should lead to a higher number of positive isolates.

The detection of Shiga toxin-producing Escherichia coli in diagnostic bovine faecal samples using vancomycin-cefixime-cefsulodin blood agar and PCR

The prevalence of complex Shiga toxin-producing Escherichia coli (STEC), i.e. STEC containing accessory virulence factors intimin (eaeA) and/or enterohaemorrhagic E. coli haemolysin (ehxA) and their serotypes were determined in diagnostic bovine faecal samples processed during a 3 months period. The presence of complex STEC was determined using PCR and vancomycin-cefixime-cefsulodin blood agar (BVCCA) using a dual approach which involved (i) direct culture of faecal samples on BVCCA followed by mutiplex PCR of BVCCA positive colonies and (ii) culture of faecal samples enriched in modified EC (mEC) broth (with a complex STEC profile determined by PCR) on BVCCA followed by multiplex PCR of BVCCA positive colonies. Using both techniques complex STEC were isolated from 23 (18.7%) of the 123 faecal samples. Complex STEC were isolated from 14 faecal samples by direct culture on BVCCA and 13 faecal samples yielded complex STEC by culture of mEC broths with a complex STEC profile on BVCCA. Only four samples were positive using both techniques. The serotypes isolated included O5:H-, O26:H-, O26:H11, O91:H21, O111:H-, O111:H8, O104:H11, O113:H21 and O157:H8. This study confirms that non-O157 STEC can be isolated from bovine faeces and that they carry types associated with human disease. This work also demonstrates that the use of a dual approach is advisable to increase the likelihood of isolating complex STEC.

Detection of hemolysin variants of Shiga toxin-producing Escherichia coli by PCR and culture on vancomycin-cefixime-cefsulodin blood agar

The presence of a hemolysin-encoding gene, elyA or hlyA, from Shiga toxin-producing Escherichia coli (STEC) was detected by PCR in each of 95 strains tested. PCR products of elyA from human STEC isolates of serovars frequently detected in Germany, such as O157:H-, O103:H2, O103:H-, O26:H11, and O26:H-, showed nucleotide sequences identical to previously reported ones for O157:H7 and O111:H- strains. Compared to them, four elyA amplicons derived from human isolates of rare STEC serovars showed identity of about 98% but lacked an AluI restriction site. However, the nucleotide sequence of an amplicon derived from a porcine O138:K81:H- STEC strain was identical to the corresponding region of hlyA, encoding alpha-hemolysin, from E. coli. This hlyA amplicon showed 68% identity with the nucleotide sequence of the corresponding elyA fragment. It differed from the elyA PCR product in restriction fragments generated by AluI, EcoRI, and MluI. Of the 95 representative STEC strains, 88 produced hemolysin on blood agar supplemented with vancomycin (30 mg/liter), cefixime (20 micrograms/liter), and cefsulodin (3 mg/liter) (BVCC). The lowest added numbers of two to six STEC CFU per g of stool or per ml of raw milk were detectable on BVCC plates after seeding of the preenrichment broth, modified tryptic soy broth (mTSB) supplemented with novobiocin (10 mg/liter), with 16 STEC strains. These strains represented the seven prevailing serovars diagnosed from German patients. However, with ground-beef samples, PCR was essential to identify the lowest added numbers of two to six STEC CFU among colonies of hemolyzing Enterobacteriaceae, such as Serratia spp. and alpha-hemolysin-producing E. coli. We conclude that preenrichment of stool and food samples in mTSB for 6 h followed by overnight culturing on BVCC is a simple method for the isolation and presumptive identification of STEC.

Cefsulodin chocolate blood agar: a selective medium for the recovery of Haemophilus influenzae from the respiratory secretions of patients with cystic fibrosis

A modified chocolate blood agar medium incorporating cefsulodin, a semi-synthetic cephalosporin, was developed and compared with non-selective chocolate blood agar and selective haemin-bacitracin blood agar for the routine isolation of Haemophilus influenzae from the respiratory secretions of patients with cystic fibrosis. The results showed that cefsulodin chocolate blood agar improved the recovery rate of H. influenzae in this group of patients. The medium was stable on storage for 10 days at 4 degrees C.

Increased efficiency of the outer membrane PhoE protein pore in Escherichia coli K-12 mutants with heptose-deficient lipopolysaccharide

The pore properties of PhoE protein channels in the outer membrane of a lipoprotein-deficient mutant and in a mutant with heptose-deficient lipopolysaccharide were investigated. The absence of lipoprotein neither affects the rate of permeation of glucose 6-phosphate or of the beta-lactam antibiotic cephsulodin through the PhoE pore nor the inhibition of cephsulodin permeation by polyphosphate. In contrast, heptose deficiency results in a 6- to 8-fold increase in the rates of permeation of glucose 6-phosphate and cephsulodin. Possible explanations for these data are discussed. It is argued that the lipopolysaccharide structure synthesized under phosphate limitation may be similar to that of the heptoseless mutant and hence that not only the structure of the PhoE protein pore but also the structure of the lipopolysaccharide may promote the uptake of Pi and Pi-containing solutes under phosphate limitation.

Cefsulodin and ceftazidime, two antipseudomonal cephalosporins

The microbiologic, pharmacokinetic, and clinical profiles of cefsulodin and ceftazidime are reviewed. Ceftazidime is a broad-spectrum beta-lactamase stable cephalosporin with excellent activity against gram-negative bacilli, including Pseudomonas aeruginosa. Cefsulodin is a narrow-spectrum cephalosporin with activity against Staphylococcus aureus and Ps. aeruginosa. Both antibiotics, which are expected to be marketed in the United States, are superior to currently available cephalosporins against Ps. aeruginosa. Cefsulodin and ceftazidime are administered by the i.m. or i.v. route, are widely distributed in body fluids and tissues, and exhibit relatively low binding to serum proteins. They are eliminated primarily through the urine, and they generally can be administered every 8 to 12 hours, depending upon the type of infection. Cefsulodin has been used successfully in the treatment of various Ps. aeruginosa infections in noncomparative studies. Ceftazidime has been successfully used as a single agent in comparative studies for Ps. aeruginosa infections. Because of its broad spectrum and its activity against penicillin-resistant and aminoglycoside-resistant Pseudomonas, ceftazidime can be used empirically as a single agent in place of combination therapy in patients with cystic fibrosis. Ceftazidime has also been useful as a single agent used empirically for treating febrile episodes in neutropenic patients and for treating hospital-acquired infections in nonneutropenic patients when Pseudomonas cannot be ruled out. Ceftazidime is a useful broad-spectrum antibiotic, particularly in the empiric therapy of nosocomial infections and in patients whose underlying conditions predispose them to Ps. aeruginosa infections. Cefsulodin may prove useful as single-agent therapy of certain infections known to be caused by Ps. aeruginosa, but its empiric use is not encouraged.

[Nonparametric approach to the determination of critical diameters. Comparison with conventional methods]

Bacteria are usually classified as susceptible (S), intermediate (l) or resistant (R) by comparison of their MICs with two reference MIC cutoff levels. Three sets Sc, Ic and Rc are thus constructed. By using agar diffusion, the same bacteria are classified as Sd, Id or Rd, by comparison of inhibition zone diameters with two reference diameter breakpoints. These Sd, Id and Rd sets are not absolutely identical with Sc, Ic and Rc respectively. Diameter breakpoints were submitted to successive adjustments until minimal differences were achieved, i.e. when the greatest possible number of elements was included in the sets: (Formula: see text) Comparison of this method with more conventional techniques emphasizes its value.

[Pharmacokinetic behavior of cefsulodin and cefotiam alone or in combination after intravenous injection of 1 gram]

Simultaneous administration by the intravenous route of 1 g of cefotiam and 1 g of cefsulodin does not alter the pharmacokinetic parameters of either compound.

Bactericidal effect of polymorphonuclear neutrophils on antibiotic-induced filaments of gram-negative bacilli

Exposure of strains of Escherichia coli to ampicillin and mezlocillin and of strains of Pseudomonas aeruginosa to azlocillin and cefsulodin caused the bacilli to elongate into filaments. The bacilli and their filaments were incubated with fresh human polymorphonuclear neutrophils (PMNs), and the phagocytic process was recorded by means of phase-contrast microscopy. The bactericidal effect of PMNs on both filaments and bacilli was quantitated by counts of colony-forming units. A single PMN phagocytized one or more filaments, some of which were as long as 90 micron and contained as many as 20 genomes. Two predominant patterns of phagocytosis of filaments were observed. When the ratio of bacteria to PMNs was low (0.2-1.8), the rate of killing was 62%-81%. When the ratio was higher (5-12), the rate of killing of both filaments and bacilli was lower. As an alternative to colony-forming units, cell mass was used as a gauge of phagocytic activity. The relative mass of killed filaments was considerably greater than that of killed bacilli; this finding indicated that filaments were much more susceptible than were bacilli to the bactericidal activity of PMNs.

[In vivo-acquired resistance to cefsulodin by a strain of Pseudomonas aeruginosa]

We isolated a Pseudomonas aeruginosa strain which was initially cefsulodin-susceptible (J1, MIC = 4 g/l) and became resistant (J2, MIC greater than 64 g/l) after 12 days of treatment of the patient with cefsulodin. Strain J2 had a constitutive beta-lactamase with hydrolytic activities similar to those of a cephalosporinase and an isoelectric point at 8.1. This enzyme (Case) may be related to the ld type. Concomitant development of resistances to various beta-lactams stable to Case suggests that other mechanisms of resistance may be involved.

[Application of a millipore membrane transfer method to the study of the activity of 4 beta-lactams on Pseudomonas aeruginosa]

In vitro activities of four cephalosporins, i.e. cefoperazone, cefsulodin, ceftazidime and CM 40874, on 31 ticarcillin-susceptible or resistant Pseudomonas aeruginosa strains were compared. Minimal inhibitory and bactericidal concentrations were determined by the conventional broth technique and by a filter membrane transfer method on agar. MICs determined by both methods were comparable for each strain. Some discrepancies were found for minimal bactericidal concentrations. Among the cephalosporins studied on ticarcillin-susceptible Pseudomonas aeruginosa strains, the most active was ceftazidime, followed by cefsulodin, CM 40874 and cefoperazone. Resistance of Pseudomonas aeruginosa to ticarcillin was associated with an overall increase in resistance to the four cephalosporins studied. These cephalosporins can be classified according to bacteriostatic and bactericidal effect in the following decreasing order: ceftazidime, CM 40874, cefsulodin and cefoperazone.

Single-dose pharmacokinetics of cefsulodin in patients with cystic fibrosis

The single-dose pharmacokinetics of cefsulodin were evaluated in 12 patients with cystic fibrosis. Each patient received 3 g of cefsulodin intravenously over 30 min. Multiple plasma and urine samples were obtained during the 6-h study period for the determination of cefsulodin. Pharmacokinetic parameters were determined by model-independent methods. Mean values for t1/2, Vss, and CLp were 1.53 h, 0.242 liters/kg, and 117.3 ml/min per 1.73 m2, respectively. Six-hour urine recovery revealed 73.2% of the administered dose with a corresponding cefsulodin urinary clearance of 75.1 ml/min. These pharmacokinetic data in patients with cystic fibrosis appear consistent with data reported for unaffected individuals.

[Comparative in vitro activity of 5 beta-lactams (cefoperazone, cefsulodin, ceftazidime, azthreonam, N-formimidoyl-thienamycin) on 90 strains of Pseudomonas aeruginosa with various levels of resistance to ticarcillin]

Five beta-lactams with anti-pseudomonal activity were tested against P. aeruginosa strains resistant to various concentrations of ticarcillin (from 256 to 8192 mg/l). MIC geometric means found for the totality of strains were as follows: 1.52 mg/l for ceftazidime; 1.80 mg/l for N-f-thienamycin; 4.79 mg/l for azthreonam; 17.3 mg/l for cefsulodin; 50.9 mg/l for cefoperazone. Activities of ceftazidime, N-f-thienamycin and azthreonam were not related to the level of ticarcillin resistance. Cefoperazone and, to a lesser degree, cefsulodin showed cross resistance with ticarcillin: these drugs were not active when ticarcillin MICs reached 512 mg/l and 4 096 mg/l respectively.

[Influence of the inoculum effect on the MIC and MBC of 5 beta-lactams against Pseudomonas aeruginosa]

MICs and MBCs of five beta-lactams , i.e. ticarcillin, azlocillin, piperacillin, cefsulodin and ceftazidime for 20 strains of Pseudomonas aeruginosa were studied with inocula ranging from 10(3) to 10(9) CFU/ml. Each antibiotic exhibited an inoculum effect at 10(5)-10(7) CFU/ml. However, ticarcillin had smaller MIC and MBC increments than the four other drugs, making it more suitable in certain cases.

[Comparative activity of azlocillin on Pseudomonas species excluding Pseudomonas aeruginosa]

The minimal inhibitory concentrations (MIC) of three acylureidopenicillins (azlocillin, mezlocillin, piperacillin) and three third generation cephalosporins (cefotaxime, cefoperazone, cefsulodin) against 249 randomized strains of Pseudomonas spp. representing 10 species other than Pseudomonas aeruginosa, were determined by the agar dilution method in Mueller-Hinton agar and compared by parametric statistical tests. Fresh clinical and environmental hospital isolates belonged to the following species: P. fluorescens (35), P. putida (37), P. stutzeri (17), P. mendocina (4), P. cepacia (37), P. pickettii (22), P. acidovorans (36), P. diminuta (5), P. paucimobilis (23), P. maltophilia (37). Azlocillin inhibited over 88% of Pseudomonas spp at 64 mg/l or less. This good antipseudomonal activity in vitro was comparable to those of piperacillin and cefotaxime with a minimal inhibitory concentrations 50 value of 8 mg/l. Against these Pseudomonas spp, the ranking order of activity was azlocillin = piperacillin = cefotaxime greater than cefoperazone greater than mezlocillin greater than cefsulodin. Like piperacillin or cefotaxime, azlocillin, was effective against ticarcillin--and aminoglycoside--resistant Pseudomonas spp. Against P. maltophilia and P. cepacia, the two Pseudomonas spp other than P. aeruginosa that are important pathogens in opportunistic infections and in their vast majority are resistant to amino glycosides, azlocillin was significantly active. Only in the case of P. maltophilia, cefoperazone had a lower minimal inhibitory concentrations 50 (8 mg/l vs. 32 mg/l).

Resistance of Pseudomonas aeruginosa mutants with altered control of chromosomal beta-lactamase to piperacillin, ceftazidime, and cefsulodin

Examination of beta-lactam susceptibility of mutants altered in the control of chromosomal beta-lactamase of Pseudomonas aeruginosa supports the view that a constitutive level of beta-lactamase is not an adequate explanation for resistance to cefsulodin and ceftazidime but could be for resistance to piperacillin which has an efficiency of hydrolysis ca. 10 times higher than does cefsulodin or ceftazidime.

Synergistic activity of cefsulodin combined with cefoxitin and sulbactam against Bacteroides species

The in-vitro activity of cefsulodin combined with sulbactam, cefoxitin or cefotaxime was investigated against 32 strains of beta-lactamase-producing Bacteroides species. Synergy of cefsulodin-sulbactam or cefsulodin-cefoxitin could be demonstrated against 30 of 32 and 32 of 32 strains tested at the concentrations readily achievable in serum. In the presence of 1 mg/l of sulbactam or cefoxitin, more than 90% of the Bacteroides isolated were inhibited by 32 mg/l of cefsulodin. The inhibitory activity of cefsulodin-sulbactam or cefsulodin-cefoxitin combinations was bactericidal against Bact. fragilis and Bact. vulgatus. In contrast, no synergistic inhibitory or bactericidal activities can be observed by the cefsoludin-cefotaxime combination. Both sulbactam and cefoxitin were potent inhibitors of beta-lactamases produced by Bact. fragilis and Bact. melaninogenicus suggesting that this inhibitory activity might be one of the factors contributing to the synergistic combinations.

Stability of cefsulodin in aqueous buffered solutions and some intravenous admixtures

The stability of cefsulodin in aqueous solutions of various pH values, buffer concentrations, ionic strengths and intravenous admixtures were studied using a stability-indicating high-pressure liquid chromatography method. The pH range of optimum stability was determined to be 3.2-5.7. Cefsulodin was more stable on the acidic and less on the alkaline side as compared with most of the other cephalosporins such as cefoxitin (pH range of optimum stability approximately 4-7). In 5% dextrose and 0.9% sodium chloride injection, cefsulodin was stable (at least 90% potent) for about 1, 17 and at least 60 days at 24 degrees, 5 degrees and -10 degrees C, respectively.

Determination of cefsulodin in biological fluids by high-pressure liquid chromatography

Cefsulodin is a third-generation cephalosporin with a unique specificity for Pseudomonas aeruginosa. To study the pharmacokinetics of this agent in children, a rapid and sensitive high-performance liquid chromatographic micromethod was developed for plasma and urine. Protein was precipitated from plasma with one volume of cold methanol, and 20 microliter of the resulting supernatant solution was injected into a Zorbax C-8 reversed-phase column. The mobile phase was composed of 4.5 parts acetonitrile and 95.5 parts of 0.035 M ammonium acetate buffer (pH 5.2). Flow rate was 1.0 ml/min and peaks were detected at 265 nm. A flow gradient from 0.3 to 2.0 ml/min over 34 min was employed for urine. The analysis had a limit of detectability of 1 microgram/ml and a between-day coefficient of variation of 4.4 and 5.0 for 100 and 10 micrograms/ml samples, respectively.

Cefsulodin sodium therapy in cystic fibrosis patients

Cefsulodin sodium is a narrow-spectrum cephalosporin with marked in vitro activity against clinical isolates of Pseudomonas aeruginosa. We have studied the antibiotic in a clinical trial in 10 patients admitted to the Pediatric Ward of the University of Virginia Medical Center with cystic fibrosis and recurrent acute lower respiratory tract infections with P. aeruginosa isolated from their sputa. The patients received 500 to 1,500 mg of cefsulodin every 6 hours by intravenous infusion for 10 to 22 days. Mean peak drug levels in plasma after 500, 1,000, and 1,500 mg were 46, 71, and 90 micrograms/ml, respectively, and the mean minimal inhibitory concentration of all organisms was 7.5 micrograms/ml. Detectable levels of cefsulodin in sputa were found in approximately half of the random samples and ranged from 2 to 5 micrograms/ml. The clinical response was satisfactory in nine (90%) of the patients. One patient gained weight and had improved pulmonary function tests but showed no reduction in sputum production and no improvement in arterial blood gas values. In pulmonary function tests, four of five patients tested showed an average 43% increase in forced vital capacity after initiation of therapy and five of five had an average 51% increase in forced expired volume in 1 s. No adverse effects were observed.

[Experimental study of the local application of silver sulfadiazine, cefsulodin and povidone-iodine in burns]

Non-infected standardized burns and those contaminated experimentally with a constant number of organisms of a selected Pseudomonas aeruginosa strain underwent varying forms of treatment with silver sulfadiazine, cefsulodin cream and povidone iodine ointment. Wound healing was controlled by evaluating the wound area. In burns which had not been infected experimentally, healing was best without any treatment. Burns treated with cefsulodin cream showed delayed healing, though this was not significant. The most significant delay, however, was observed in wounds treated with povidone iodine. Wounds infected with Pseudomonas healed considerably better than the control group when treated prophylactically with silver sulfadiazine and cefsulodin. However, burns treated with povidone iodine again showed delayed healing.

Activity of cefsulodin, other beta-lactams, and aminoglycosides against Pseudomonas aeruginosa

Cefsulodin was the most active of the cephalosporins and exhibited 4-16 times more activity than carbenicillin or ticarcillin against 50 clinical isolates of Pseudomonas aeruginosa. Azlocillin and piperacillin showed good activity, while tobramycin was the most effective aminoglycoside. The activity of cefsulodin was unaltered by increases in inocula, but resistance was induced easily. When combined with gentamicin, no synergistic or antagonistic activity was observed against multiply resistant isolates.

Penetration of cefsulodin into bronchial secretions

The objective of this study was to evaluate the penetration of cefsulodin, a new cephalosporin active against Pseudomonas aeruginosa, into the bronchial secretions. The study was carried out in 28 patients with respiratory infections; 11 patients received a single dose of 1 g i.v. (bolus); 17 patients received multiple doses of 1 g every 8 h for 48 h. Simultaneous samples of blood and bronchial secretions were collected 30 min and 1, 2, 4 and 6 h after injection. Bronchial secretions were obtained from 23 patients by means of fiberoptic bronchoscopy and in 5 tracheostomized patients (with severe respiratory insufficiency) through a tracheostomy cannula. The assays of cefsulodin were performed by means of the microbiological agar diffusion technique. The results of the study showed a noticeable penetration of the drug into the bronchial secretions, with a mean peak reaching 3.1-5.3 micrograms/ml at the 3rd or 4th hour, a slow elimination and residual levels at 6 h ranging between 2.0 and 6.0 micrograms/ml. The rate of penetration was not influenced by the administration of multiple doses of the drug. The ratios between bronchial concentrations and simultaneous serum concentrations ranged between 10 and 30%, corresponding to the usual values found for other cephalosporins. In conclusion, this study provides satisfactory results and confirms the presence of bronchial levels capable of inhibiting P. aeruginosa.

[Combination action of sisomicin, dibekacin and cefotetan, cefotaxime, latamoxef, and cefsulodin against Escherichia coli, Serratia marcescens, and Pseudomonas aeruginosa]

The combined actions of sisomicin (SISO), dibekacin (DKB) and cefotetan (CTT), cefotaxime (CTX), latamoxef (LMOX), cefsulodin (CFS) against E coli KC-14, S. marcescens T-55 and P. aeruginosa E-2 were studied. The following results were obtained. The combination of SISO-CTT, SISO-CTX, SISO-LMOX, SISO-CFS, DKB-CTT, DKB-CTX, DKB-LMOX and DKB-CFS using the checker board dilution method on E. coli KC-14, S. marcescens T-55, P. aeruginosa E-2 were found to have a synergistic effect and the minimum FIC index values were 0.26--0.50 for SISO and 0.28--0.75 for DKB, respectively. With the killing kinetic method, all combinations tested showed a synergistic effect.

Synergy between the iron chelator deferoxamine and the antimicrobial agents gentamicin, chloramphenicol, cefalothin, cefotiam and cefsulodin

Synergy between the iron chelator deferoxamine in the presence or absence of ascorbic acid and gentamicin, chloramphenicol, cephalothin, cefotiam or cefsulodin, used against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, proteus mirabilis and species of Salmonella, Enterobacter, Pseudomonas and Providencia, was determined by measuring the effect of the drugs and combination of drugs on growth of the bacteria in an automated turbidimeter. The combination of drugs was considered to be synergistic when the growth inhibiting effect of the combination was greater than that of the combined action of each of the drugs separately. Deferoxamine plus ascorbic acid together with either gentamicin or cefsulodin showed synergy in 10 out of 10, and 5 out of 6 cultures respectively, whereas deferoxamine plus ascorbic acid with chloramphenicol, cephalothin or cefotiam was synergistic in 6 out of 14, 5 out of 11, and 3 out of 6 cultures. This synergistic effect was much lower when microorganisms were incubated with deferoxamine combined with the various antibiotics but without ascorbic acid. Ascorbic acid alone had no synergistic effect. When deferoxamine was saturated with iron, its antibacterial effect was completely abolished.

Frequent antibiotic therapy improves survival of cystic fibrosis patients with chronic Pseudomonas aeruginosa infection

During the period 1971-75, 51 cystic fibrosis (CF) patients who contracted chronic P. aeruginosa infection were treated at the Danish CF centre with anti-pseudomonas chemotherapy only when their clinical condition deteriorated considerably. During the period 1976-80, 58 CF patients who contracted chronic P. aeruginosa infection were treated at the Danish CF centre with anti-pseudomonas chemotherapy on a regular basis every 3 months. Each routine 24 day-course of chemotherapy consisted of tobramycin in combination with carbenicillin or other beta-lactam antibiotics with activity against P. aeruginosa. In case of allergy or resistant strains monotherapy with tobramycin was used. The 5-year survival of CF patients from the time of the onset of the chronic P. aeruginosa infection increased from 54% in the first period to 82% in the second period (p less than 0.05), and lung function (peak expiratory flow rate) also improved significantly. It is concluded that intensive "maintenance" chemotherapy against P. aeruginosa improves survival and quality of life of CF patients although permanent eradication of P. aeruginosa is not accomplished.

[Cefsulodin in the treatment of Pseudomonas meningitis]

Three patients with meningitis due to Pseudomonas aeruginosa (in one patient following a neurosurgical procedure and in two patients following severe head trauma with multiple skull bone fractures and liquorrhea) were treated with cefsulodin in combination with other antibiotics (aminoglycosides/acylureido penicillins). All of the patients were cured. Two patients received intraventricular administrations of aminoglycosides in addition to systemically applied antibiotics. After recurrence of pseudomonas meningitis in one patient in spite of the intraventricular application of an aminoglycoside, definite cure could only be obtained by additional intraventricular application of cefsulodin. The third patient was cured by systemic administration of cefsulodin and amikacin. The value of cefsulodin is discussed with reference to obtainable ventricular and lumbar CSF concentrations.

aeruginosa]

The therapeutic efficacy and safety of Cefpiramide (CPM, SM-1652) at a 2 g/day dose were objectively compared with those of Cefsulodin (CFS) at a 2 g/day dose in patients with chronic complicated urinary tract infections (UTI) by P. aeruginosa in a double-blind study at 46 institutions in Japan. The results are as follows: The therapeutic efficacy was analyzed in 254 patients (136 cases administered CPM and 118 cases administered CFS) after excluding 20 cases as drop-out. Among 254 cases, the number of patients with infection of P. aeruginosa was 190 cases (100 cases administered CPM and 90 cases administered CFS), while that with infection of organisms other than P. aeruginosa was 64 cases (36 cases administered CPM and 28 cases administered CFS). By the administration of a 2 g/day dose for 5 days, the overall clinical effective rate of CPM was significantly higher than that of CFS in total patients. When the patients were classified into 2 groups with respect to causative organisms (P. aeruginosa and others), the clinical effective rate of CPM in patients with infections of P. aeruginosa was significantly higher than that of CFS, while the clinical effective rate of CPM in patients with infection of other organisms than P. aeruginosa was the same as that of CFS. As to the bacteriological effect on bacteriuria, the eradication rate of CPM was significantly higher than that of CFS not only against all causative organisms but also against P. aeruginosa. The rate of replacement by S. faecalis was significantly higher in the CFS-treated group than in the CPM-treated group. The same result was obtained on the rate of replacement by other organisms. The MIC values of CPM for isolated organisms before drug administration were lower than those of CFS. The incidence rates of side effects and the abnormal findings of clinical laboratory tests were the same for the CPM- and CFS-treated groups. From the results, it was concluded that CPM is a useful drug for the treatment of patients with chronic complicated urinary tract infections caused by P. aeruginosa.

[Topical administration of cefsulodin in postoperative Pseudomonas aeruginosa infection of the middle ears]

The clinical evaluation for cefsulodin (CFS) against P. aeruginosa was studied in postoperative infections of chronic otitis media by means of washing the middle ear with the drug, and the following results were obtained; CFS treatment was given to 5 cases, and the clinical responses were excellent in 4 and good in 1 case. P. aeruginosa in otorrhea was eradicated within several days, and otorrhea disappeared in all the cases. No side effect was observed in all cases.

The response of Pseudomonas aeruginosa to azlocillin, ticarcillin and cefsulodin

The morphological response of Pseudomonas aeruginosa to azlocillin, ticarcillin and cefsulodin was investigated by electron microscopy. Each antibiotic initially caused the formation of filaments. On further incubation in the presence of azlocillin, deposits of dense intracellular material were observed; these were absent from cells exposed to the other two antibiotics. On continued incubation, lysis of the filaments occurred, but the mode of lysis differed between the antibiotics: azlocillin caused breakage at a restricted number of sites in the cell wall, ticarcillin produced breakage at many points and cefsulodin caused extensive cell-wall damage. In addition, ticarcillin and cefsulodin appeared to cause more lysis and spheroplast formation than did azlocillin. The morphological changes correlated with turbidimetric measurements of bacterial response to the three antibiotics, which showed ticarcillin and cefsulodin to act more rapidly than azlocillin.

Simultaneous determinations of cefsulodin and cefotiam in serum and bone marrow blood by high-performance liquid chromatography

A high-performance liquid chromatographic method is described for the simultaneous determinations of cefsulodin and cefotiam in serum and bone marrow blood samples. After extraction with acetonitrile, the cephalosporins were applied to a reverse-phase column with an internal standard, cefazolin; the mobile phase was a mixture of 0.005 M tetrabutylammonium phosphate and methanol (35:65, v/v). The method yielded satisfactory resolutions for these agents, and the results were compared with those obtained using the microbiological method. The statistical analysis of the relationship between the methods gave a good correlation for all of these agents and samples. The concentrations of cefsulodin and cefotiam, concurrently administered by the intravenous route to patients subjected to artificial total joint prosthesis, in serum and bone marrow blood collected at 0.5 and 1 hr postinjection were almost equivalent.

Alternative antibiotics for the treatment of Pseudomonas infections in cystic fibrosis

We have investigated the effectiveness of seven new beta-lactam antibiotics, azlocillin, piperacillin, ceftazidime, cefsulodin, cefoperazone, latamoxef (moxalactam), and cefotaxime, against acute pulmonary exacerbations caused by Pseudomonas aeruginosa in cystic fibrosis. Three hundred and fifty-five strains of Ps aeruginosa isolated from 310 sputum cultures (190 cystic fibrosis patients) were tested for susceptibility to the drugs by determination of minimal inhibitory concentrations (MIC). The highest activity was shown by ceftazidime (6% resistant strains) followed by cefsulodin and piperacillin (15 and 16% resistant strains); very low activity was found for cefotaxime and latamoxef (moxalactam). Ceftazidime was the most active drug against 32 pseudomonas isolates that were resistant to both carbenicillin and aminoglycosides (78% susceptible). A randomized, double-blind trial of azlocillin, piperacillin, ceftazidime, cefsulodin or cefoperazone was performed in 111 cystic fibrosis patients with predominant and susceptible pseudomonas in their sputum. Results were evaluated by a clinical, radiological and bacteriological scoring system: the best results were obtained with ceftazidime, followed by cefsulodin and piperacillin. However, pseudomonas was eradicated in only 22 (23%) of the cases with the most active drugs and persisted or reappeared in all the cases 1 to 3 months later. Ceftazidime always eradicated Staph. aureus and Haemophilus influenzae associated with pseudomonas. Similar eradication occurred nearly always with cefsulodin but rarely with the other drugs. No serious drug reaction occurred but a later fever and rash with piperacillin, transient diarrhoea with cefoperazone, vomiting with cefsulodin, and very frequent eosinophilia with ceftazidime should be mentioned. These five drugs offer, in varying degree, alternatives to traditional anti pseudomonas antibiotics in cystic fibrosis pulmonary infections, but they should be used only against well-proven resistant strains. Ceftazidime is best and cefotaxime and latamoxef (moxalactam) least useful.

[Comparative bactericidal activity of cefsulodin and ceftazidime on Pseudomonas aeruginosa]

This research concerns the bacteriostatic and the bactericidal activity of two beta-lactams (cefsulodin and ceftazidime) on ten strains of Pseudomonas aeruginosa affected by carbenicillin. Additionally to classical approaches in the broth and agar technics, a method of culture on filter membrane is used. The results obtained after a 2 hours and 24 hours contact are reported. The resulting values of minimum inhibitory concentrations are comparable. As far as minimum bactericidal concentrations values are concerned, there is no significant difference between the two methods or between the two antibiotics. The analysis of the bactericidal effect of a 2 hours contact allows no inference relative to the comparative effect of the two antibiotics. Each strain of P. aeruginosa has its specific behaviour, and there seems to be no way to extrapolate from their minimum inhibitory concentrations the bactericidal effect of cefsulodin and ceftazidime.

[Pseudomonas aeruginosa: acquired in vitro resistance to beta-lactams]

The development of resistance acquired in vitro to 5 semi-synthetic penicillins: carbenicillin, ticarcillin, azlocillin, mezlocillin, piperacillin and to 5 cephalosporins: cefotaxime, cefoperazone, moxalactam, cefsulodin and ceftazidime, was compared in 6 strains of Pseudomonas aeruginosa. The strains were selected on the basis of their phenotypic resistance: 3 were susceptible to all the betalactam antibiotics tested, 1 was resistant to carbenicillin and ticarcillin but remained susceptible to the others, 2 were susceptible to cefsulodin and ceftazidime but resistant to the others. The development of resistance was investigated by subsequent passages in liquid medium: up to 15 passages or up to an MIC of 4 096 mg/l for a penicillin or 512 mg/l for the cephalosporins. Irrespectively of the phenotypic resistance, for all cephalosorins the MIC became greater than or equal to 64 mg/l and very often greater than or equal to 512 mg/l after 1 to 3 passages. For the penicillin susceptible strains very high MICs were obtained more rapidly with azlocillin and piperacillin (1-2 passages) than with carbenicillin or ticarcillin (5-9 passages). These results are not in favour of a monotherapy with betalactam antibiotics, especially cephalosporins, in the treatment of Pseudomonas aeruginosa infections, but suggest the preferential use of carbenicillin and especially ticarcillin for sensitive isolates.

[Cefoperazone, cefsulodin and ceftazidime--3 cephalosporins active against Pseudomonas in comparison with their monobactam analogs]

This study compares the in vitro activity of three cephalosporins - ceftazidime, cefoperazone, cefsulodin and their monobactam analogues for 144 strains of Pseudomonas aeruginosa. Media variation studies are performed and the effect of human serum and anaerobic conditions on MIC is investigated. A significant inoculum effect is considered as a sign of instability against beta-lactamases. Ceftazidine inhibits nearly all pseudomonads at concentrations between 2 and 4 micrograms/ml being significantly more active than the other antibiotics tested. The level of activity of all monobactams tested is lower than that of the homologous cephalosporins. The counterpart of ceftazidine is also the most effective monobactam but the counterpart of cefsulodin shows no activity against pseudomonads.

Cefsulodin pharmacokinetics in patients with various degrees of renal function

The pharmacokinetics of cefsulodin were characterized in 19 patients with different degrees of renal function after a single 500-mg, 30-min intravenous infusion. Six subjects had a creatinine clearance (Clcr) of greater than 100 ml min-1 (group I), eight had a Clcr of between 12 and 42 ml min-1 (group II), and five had a Clcr of less than 10 ml min-1 (group III). Nine plasma and four urine samples were collected in the first 36 h. The plasma concentration-time data were fitted to a two-compartment open model. The mean beta-phase half-life was 1.77, 6.37, and 10.12 h in groups I, II, and III, respectively. A significant decline in plasma clearance (Clp) was also noted between the three groups: 136 to 49.6 to 27.2 ml min-1 in groups I, II, and III, respectively. Steady-state volume of distribution was 0.26 liter kg-1, regardless of renal function. The observed linear relationship between Clp and Clcr (Clp = 24.09 + 0.765 Clcr; r = 0.9566) can be utilized to revise dosage schedules for patients with any degree of renal impairment. The nonrenal clearance of cefsulodin was also noted to be significantly lower in groups II and III than in group I. Further investigations will be necessary to elucidate the mechanism(s) responsible for the decrease in the nonrenal clearance of cefsulodin.

Kinetics and significance of the activity of the Sabath and Abrahams' beta-lactamase of Pseudomonas aeruginosa against cefotaxime and cefsulodin

All Pseudomonas aeruginosa strains produce Sabath and Abrahams' (SA) enzyme, as inducible beta-lactamase. Hydrolysis of cefotaxime by this enzyme, although slow in terms of Vmax was efficient when the parameter Vmax/Km (physiological efficiency (Pollock, 1965)) was considered. Hydrolysis of cefsulodin was not detectable in assays used and enzyme binding (Ki) was poor, ensuring a very low physiological efficiency. Physiological efficiency represents a measure of enzyme function under low substrate (antibiotic) conditions, as apply in the periplasm; consequently SA enzyme might protect the cell against cefotaxime, but not cefsulodin. This depends on enzyme induction and retention within the periplasm. Agar checkerboard studies indicated the SA inducer cephaloridine antagonized the activity of cefotaxime against most (12/14) Ps. aeruginosa strains but cefsulodin against only a minority (2/14). Cephaloridine/cefotaxime antagonism was lost in uninducible (SAI-) or constitutive (SAIcon) mutants where SA expression was independent of cephaloridine concentration. This indicated the antagonism was SA dependent. Cefotaxime plate MICs against parent SAI+ and uninducible SAI- organisms were similar indicating cefotaxime did not induce SA enzyme in these tests. Cefotaxime was however much less active against the SAI+ organism than the SAI- when log phase broth cultures were exposed to antibiotic and incubation was extended to 30 h. This correlated with observed SA induction in the SAI+ organism. Cefsulodin MICs against SAI+ and SAI- organisms were similar and no difference existed in activity, over long periods against broth cultures. Overall, results indicated that SA enzyme, if induced, constituted a defense against cefotaxime but not cefsulodin and this correlated with the physiological efficiency results. To what degree induction occurs in vivo during cefotaxime therapy of pseudomonal infections remains unknown.

Susceptibility of 324 nonfermentative gram-negative rods to 6 cephalosporins and azthreonam

Susceptibility of 324 isolates of nonfermentative gram-negative bacteria to cephalothin, cefamandole, cefoxitin, ceftazidime, cefsulodin, and azthreonam was determined by agar dilution and disc diffusion techniques. With the exception of Moraxella species, first- and second-generation cephalosporins were minimally active against nonfermenters tested. Cefsulodin and azthreonam were mainly active against Pseudomonas aeruginosa. In contrast, ceftazidime and ceftriaxone exhibited wider activity spectra. Cefsulodin and ceftazidime were the most active against P. aeruginosa, followed by azthreonam and ceftriaxone. Ceftazidime was the only drug with significant activity against Pseudomonas maltophilia and Pseudomonas fluorescens/Pseudomonas putida, and was also the most active against Pseudomonas cepacia. Acinetobacter calcoaceticus and Alcaligenes strains were most sensitive to ceftazidime, followed by ceftriaxone and azthreonam. Ceftriaxone was the most active against moraxellas, followed by cefamandole/cefoxitin, ceftazidime, cephalothin, cefsulodin, and azthreonam. Ceftazidime was the most active against uncommonly isolated nonfermenters. Results observed in this study reflect a potential use for ceftazidime in therapy of infections caused by most gram-negative nonfermenters; therapy with cefsulodin and azthreonam in nonfermenter infections should be restricted to those caused by P. aeruginosa, and that with ceftriaxone reserved for non-P. aeruginosa infections.

[Clinical investigation of combined therapy (cefotiam, sulbenicillin and cefsulodin) against infections complicated by acute leukemia]

Prophylaxis effect and clinical therapy of combination use of cefotiam (CTM), sulbenicillin (SBPC) and cefsulodin (CFS) have been investigated, and the results were as follows. 1. Prophylaxis effect of CTM-SBPC combination therapy was very useful. CTM-SBPC combination therapy was performed to patients who are at high risk for infectious complications. Prophylaxis effect of CTM-SBPC was judged by fever over 38 degrees C, and was better than usual antibiotic treatment. 2. CTM-SPBC-CFS combination therapy was performed against severe infections during early remission, and the overall effectiveness rate was 83.3% (5/6). 3. No remarkable side effect was observed in this investigation.

[A study on the disc sensitivity test for cefsulodin]

Susceptibilities of 101 strains of 34 bacterial species to cefsulodin (CFS) were determined by the 2-fold agar dilution method in parallel with the diameter of inhibition zone by the single-disc method, under the experimental condition established by Kanazawa. The experiments demonstrated significant correlation between MIC by the dilution method and diameter of inhibition zone in each of conventional assay of the over-night (about 16 hours) incubation, delayed assay (about 24 hours incubation), and rapid assay (about 3--4 or 5--6 hours incubation), thus confirming applicability of the single-disc assay for CFS. Analysis of the data obtained by using CFS disc containing 30 micrograms revealed the primary regression equation to be: D (diameter, mm) = 30.0 - 12.1 log MIC (micrograms/ml) in conventional assay, D = 36.3 - 15.6 log MIC (micrograms/ml) in delayed assay, D = 25.2 - 9.0 log MIC (micrograms/ml) in 5--6 hours rapid assay, and D = 20.4 - 6.4 log MIC (micrograms/ml) in 3--4 hours rapid assay, respectively. The range of variations in MICs estimated from the diameters of inhibition zone by the disc test was then calculated in comparison with that in MICs determined by the 2-fold agar dilution assays, as reference for the experimental errors which may be involved in the estimation of MICs of CFS by the single-disc assay.

[Clinical study of cefsulodin on infectious diseases in otorhinolaryngological field]

The clinical effect of cefsulodin (CFS) on Pseudomonas species infections in otorhinolaryngologic field was studied in 10 patients. The overall clinical effectiveness was 80% (excellent 4, good 4, poor 2). The bacteriological response of CFS against Pseudomonas species was evaluated from 11 strains. Eradication rate of Pseudomonas species was 82%. In 1 case, body temperature was rised after injection. No abnormal laboratory findings, relating to the drug, were observed after treatment.