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PubMed2002

Comparative in-vitro activities of ertapenem against aerobic bacterial pathogens isolated from patients with complicated intra-abdominal infections.

The in vitro activities of ertapenem, ceftriaxone, amoxicillin-clavulanate, ampicillin-sulbactam, and piperacillin-tazobactam were compared against 1018 aerobic bacterial pathogens isolated from 531 patients with complicated intra-abdominal infection. Enterobacteriaceae accounted for 66.3% of the aerobic bacteria; Escherichia coli was the most common isolate. The ertapenem minimal inhibitory concentration was < or = 2 microg/mL for 74.6% of isolates and > or = 8 microg/mL for 21.9% (including isolates of enterococci, methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa). Against Enterobacteriaceae, ertapenem was the most potent and the most active drug evaluated (100% susceptible), followed by ceftriaxone (98% susceptible), piperacillin-tazobactam (96% susceptible), amoxicillin-clavulanate (80% susceptible), and ampicillin-sulbactam (64% susceptible). Piperacillin-tazobactam was the only drug evaluated with clinically useful activity against P. aeruginosa. In summary, ertapenem was highly active in vitro against many clinically important aerobic intra-abdominal bacterial pathogens, especially Enterobacteriaceae.

Anti-Bacterial Agents↗
PubMed2003

Retrospective analysis of antibiotic susceptibility patterns of respiratory isolates of Pseudomonas aeruginosa in a Turkish University Hospital.

BACKGROUND: Lower respiratory tract infections due to Pseudomonas aeruginosa have a high mortality rate. Antibacterial activity of various antibiotics against P. aeruginosa isolated from each hospital depends on the variety or amount of antibiotics used in each hospital. METHOD: A total of 249 respiratory isolates of Pseudomonas aeruginosa in Sivas (Turkey) were included between January-1999 and January-2002. Isolates were tested against 14 different antibiotics by a disc diffusion method or standardized microdilution technique. RESULTS: Organisms were cultured from the following specimens: sputum (31.3%), transtracheal/endotracheal aspirates (37.8%), and bronchial lavage (30.9%). Isolates in bronchial lavage were highly susceptible to cefoperazone and aminoglycosides. Resistance to ampicillin/sulbactam was 98.8%, ticarcillin 40.1%, ticarcillin/clavulanic acid 11.2%, piperacillin 21.8%, aztreonam 66.6%, cefotaxim 75.4%, ceftriaxone 84.2%, cefoperazone 39.0%, ceftazidime 50.8%, gentamicin 57.5%, tobramycin 58.4%, amikacin 25.4%, ciprofloxacin 16.1%, and imipenem/cilastatin 21.6%. The term multidrug-resistant P. aeruginosa covered resistance to imipenem, ciprofloxacin, ceftazidime, gentamicin, and piperacillin. 1.2% of isolates were multidrug-resistant. CONCLUSIONS: These findings suggest that amikacin resistance increases progressively in Turkey. Piperacillin and ticarcillin/clavulanate were the most active agents against both imipenem- and ciprofloxacin-resistant isolates in our region.

Journal Article↗
PubMed2006

Using local microbiologic data to develop institution-specific guidelines for the treatment of hospital-acquired pneumonia.

BACKGROUND: While current guidelines recommend consideration of local microbiologic data when selecting empiric treatment for hospital-acquired pneumonia (HAP), few specifics of how to do this have been offered. METHODS: We conducted a retrospective analysis of HAP pathogens in 111 consecutive patients who acquired HAP during July to December 2004 and had a corresponding positive culture finding for a bacterial pathogen. These data were used to develop institution-specific guidelines. RESULTS: The most common bacteria identified were Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa, which were associated with 38%, 25%, and 19% of pneumonias, respectively. Susceptibility of Gram-negative bacteria to piperacillin-tazobactam and cefepime was 80% and 81%, respectively. The isolation of organisms resistant to piperacillin-tazobactam or cefepime was significantly more frequent in patients who had been hospitalized > or = 10 days. Of Gram-negative isolates resistant to piperacillin-tazobactam or cefepime, ciprofloxacin was active against < 10%, while amikacin was active against > 80%. New treatment guidelines were developed that divided the American Thoracic Society/Infectious Diseases Society of America "late onset/risk of multidrug-resistant pathogens" group of patients into two subcategories: "early-late" pneumonias (< 10 days of hospitalization) and "late-late" pneumonias (> or = 10 days of hospitalization). Guideline-directed treatment regimens would be predicted to provide adequate initial therapy for > 90% of late-onset pneumonias at our institution. CONCLUSIONS: Current guidelines suggest adding either an aminoglycoside or a fluoroquinolone to beta-lactam therapy for empiric Gram-negative coverage. However, in our institution, adding ciprofloxacin would not appreciably enhance the likelihood of providing initial appropriate antibiotic coverage. This underscores the importance of employing a systematic analysis of local data when developing treatment guidelines.

Anti-Bacterial Agents↗
PubMed1981

Effects of inducible beta-lactamase and antimicrobial resistance upon the activity of newer beta-lactam antibiotics against Pseudomonas aeruginosa.

The activity of carbenicillin, ticarcillin, piperacillin, cefotaxime, moxalactam, and N-formimidoyl thienamycin was evaluated against 262 clinical isolates of Pseudomonas aeruginosa. There were 242 (92%) of the isolates that were susceptible to carbenicillin or ticarcillin by an agar dilution method. Against this population of susceptible isolates, the median MICs were 1.56 microgram/ml of N-formimidoyl thienamycin, 3.13 microgram/ml of piperacillin, 25 microgram/ml of ticarcillin, 25 microgram/ml of cefotaxime, 50 microgram/ml of carbenicillin and 50 microgram/ml of moxalactam. N-Formimidoyl thienamycin was the only beta-lactam antibiotic not affected by an inducible beta-lactamase detected in 24 randomly selected susceptible isolates by a disk approximation assay, while cefotaxime was inactivated to a greater extent than any of the other beta-lactam antibiotics. Resistance to carbenicillin and ticarcillin was noted in 20 isolates (8%); these were susceptible to N-formimidoyl thienamycin, but cross-resistance with piperacillin, cefotaxime, and moxalactam was frequent. Only four of these resistant isolates were found to have a constitutive beta-lactamase. Gentamicin resistance occurred in 51 isolates (19%) and was an independent variable of resistance to the beta-lactam drugs.

Anti-Bacterial Agents↗
PubMed1988

[Susceptibility of gram-negative bacterial isolates to six beta-lactam and two aminoglycoside antibiotics at our university hospital].

Susceptibilities of Gram-negative bacterial strains isolated at the University Hospital in 1987 to six beta-Lactam antibiotics (azthreonam cefmetazole, ceftizoxime, latamoxef, aminobenzyl-penicillin and piperacillin) and two aminoglycoside antibiotics (gentamicin and amikacin) were examined by agar dilution and the agar diffusion method. Results obtained from both methods correlated well in most of the strains. Most of the strains belonging to Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae and Proteus mirabilis were sensitive to the beta-lactam antibiotics except aminobenzyl-penicillin and piperacillin. They were also sensitive to aminoglycoside antibiotics. Most strains of Citrobacter freundii, Enterobacter cloacae and Serratia marcescens were sensitive to azthreonam, latamoxef and aminoglycosides, but were less sensitive to other beta-lactams. Acinetobacter calcoaceticus was generally resistant to beta-lactams except ceftizoxime, but was sensitive to aminoglycosides. More than half of the strains of Pseudomonas aeruginosa were sensitive to azthreonam, piperacillin and aminoglycoside antibiotics and only latamoxef was active in Pseudomonas maltophilia.

Aminoglycosides↗
PubMed1997

A compilation of studies assessing the in vitro activity of meropenem and comparators in 84 laboratories throughout Europe.

OBJECTIVE: To compile the results of investigations conducted in 84 centers throughout Europe of the in vitro activity of meropenem and a standard set of comparators against some 12 000 Gram-positive, Gram-negative, aerobic and anaerobic bacteria. METHODS: Recent clinical isolates from 84 European countries were tested using Mueller---Hinton broth or agar (aerobes and nutritionally fastidious species) or Wilkins---Chalgren medium (anaerobes) for susceptibility to meropenem, imipenem, cefotaxime, ceftazidime, piperacillin, ciprofloxacin and gentamicin (aerobes) or meropenem, imipenem, clindamycin and metronidazole (anaerobes). RESULTS: Whether compared across studies or across countries, meropenem and imipenem were the only compounds that produced uniform and predictable activity. The activity of ceftazidime and cefotaxime was compromized because of instability to both chromosomally mediated and new plasmid-mediated (transferable) beta-lactamases. This effect was even more pronounced with piperacillin. Resistance to gentamicin was commonplace, although variable between countries; strains resistant to ciprofloxacin occurred in many genera of Enterobacteriaceae and amongst the pseudomonads. Metronidazole was uniformly active against anaerobes but there were many clindamycin-resistant strains. Resistance, or diminished susceptibility, amongst Streptococcus pneumoniae was found frequently, but of the beta-lactams tested, only ceftazidime and piperacillin produced minimum inhibitory concentration values that could compromize therapeutic efficacy outside the central nervous system. CONCLUSIONS: These data provide further evidence of the high incidence of antibiotic resistance in Europe, notably in France, Spain and Italy. Fortunately, the carbapenems are highly stable to the enzymes that hydrolyze cephalosporins and penicillins. Hence, they retain an essentially unaltered and exceptional antimicrobial spectrum, embracing the vast majority of strains resistant to the other comparators, although meropenem was more reliable than imipenem against Pseudomonas aeruginosa.

Journal Article↗
PubMed2000

[Antibiotic resistance monitoring of nosocomial clinical isolates]

The authors evaluate the epidemiological trend of in vitro resistance of 2,196 clinical isolates, chiefly Gram-negative, in Caltagirone hospital in 1998/99 to piperacillin-tazobactam, piperacillin, cefotaxime, ceftazidime, ceftriaxone, imipenem, ciprofloxacin and tobramicin. The resistance percentage is reported for each year in order to study the phenomenon in time. The following results were obtained: resistance frequently increases or rarely stays constant in time for all antibiotics used; the resistance percentage is very high for some strains of bacteria; monitoring of resistance in a hospital can help in choosing the empirical therapy. Piperacillin-tazobactam, imipenem and ciprofloxacin were the most active drugs against clinical isolates.

Journal Article↗
PubMed1992

Cefoxitin-induced antibiotic resistance in Enterobacter species in the community hospital.

The aim of this study was to determine whether beta-lactamases could be induced by cefoxitin in the community hospital, since this problem of antibiotic resistance has been shown to exist at the tertiary care level. One hundred sixty-six Enterobacter species isolated from patients in two community hospitals in Dayton, Ohio, were tested for cefoxitin induction of beta-lactamase production by a disk-approximation method. Piperacillin and cefoxitin disks were placed in approximation to each other on Mueller-Hinton plates inoculated with Enterobacter species with appropriate controls. Three Enterobacter strains (1.8%) showed truncation of the zone of inhibition (indicating beta-lactamase induction) with sensitivity to both cefoxitin and piperacillin. However, 84 strains (50.6%) showed truncation around the piperacillin disk with resistance to cefoxitin. One hundred fifty (90.0%) strains showed resistance to cefoxitin. These data indicate that cefoxitin induction of beta-lactamases in Enterobacter species is indeed a potential problem in incurring antibiotic resistance in the community hospital.

Cefoxitin↗
PubMed2003

[Influence of consensual protocols on the use of antibiotics and bacterial resistance in a general hospital. A prospective study 1995-2000].

Reasoned and consensual protocols, by means of diversification of the use of antibiotics, significantly influence their consumption, preventing and reducing the development of bacterial resistance against the Gram-negative microorganisms most frequently isolated in general hospitals. The increase in the consumption of piperacillin-tazobactam was found to be significantly associated with an increased resistance of E. cloacae, but less so in K. pneumoniae and E. coli. Its activity against P. aeruginosa and against P. mirabilis was not affected throughout the study and it maintained a high sensivity to the end against P. aeruginosa and against P. mirabilis and partial recovery of activity against A. baumannii. No statistically significant differences were found between the stable consumption of cefotaxime, ciprofloxacin, ceftazidime and imipenem and bacterial resistance against E. coli, P. aeruginosa, P. mirabilis, K. pneumoniae, E. cloacae and A. baumannii. Imipenem presented greater activity against E. coli, K. pneumoniae, E. cloacae and A. baumannii. Piperacillin-tazobactam showed greater activity against P. aeruginosa, while ciprofloxacin showed the least activity against E. coli and P. mirabilis. Cefotaxime had the least activity against E. cloacae, P. aeruginosa and A. baumannii. Ceftazidime showed stable activity and was similar to piperacillin-tazobactam against E. coli, P. mirabilis, K. pneumoniae, E. cloacae and A. baumannii.

Anti-Bacterial Agents↗
PubMed2004

[Mechanisms of resistance in Enterobacteriaceae towards beta-lactamase antibiotics].

Except for Salmonella spp., all Enterobacteriaceae produce intrinsic chromosomal encoded beta-lactamases which, beside their physiologic role in cell-wall synthesis and natural beta-lactam protection, are responsible for intrinsic resistance of individual species among Enterobacteriaceae. E. coli and Shigella spp. produce a small amount of AmpC beta-lactamases and are susceptible to ampicillin and other beta-lactam antibiotic agents. Enterobacter spp, C. freundii, Serratia spp., M. morganii, P. stuarti and P. rettgeri produce small amounts of inducible AmpC beta-lactamases which are not inhibited by beta-lactamases inhibitor, causing intrinsic resistance to ampicillin, co-amoxiclav and first-generation cephalosporins. K. pneumoniae produces small amounts of SHV-1 beta-lactamases, and K. oxytoca chromosomal K1 beta-lactamase, causing resistance to ampicillin, carbencillin, ticarcillin and attenuated zone of inhibition to piperacillin, compared to piperacillin with tazobactam. They are susceptible to beta-lactamase inhibitors. Whereas P. mirabilis shows a minor chromosomal expression of beta-lactamases, P. vulgaris produces chromosomal beta-lactamases of class A (cefuroximases), causing resistance to ampicillin, ticarcillin, and first- and second-generation cephalosporins. Antibiotics have caused the appearance of acquired or secondary beta-lactamases, with the sole function of protecting bacteria from antibiotics. The production of broad-spectrum beta-lactamases (TEM-1, TEM-2, SHV-1, OXA-1) results in resistance to ampicillin, ticarcillin, first-generation cephalosporins and piperacillin. A high level of beta-lactamases leads to resistance to their inhibitors. The plasmid-mediated extended-spectrum beta-lactamases (ESBLs) are of increasing concern. Most are mutants of classic TEM- and SHV-beta-lactamases types. Unlike these parent enzymes, ESBLs hydrolyze oxymino-cephalosporins such as cefuroxime, cefotaxime, ceftriaxone, ceftizoxime, ceftazidime, cefpirome and cefepime, aztreonam, as well as penicillins and other cephalosporins, except for cephamycin (cefoxitin and cefotetan). They are inhibited by beta-lactamase inhibitors. AmpC beta-lactamases are chromosomal and inducible in most Enterobacter spp., C. freundii, Serratia spp., M. morganii and Providentia spp. They are resistant to almost all penicillins and cephalosporins, to beta-lactamase inhibitors and aztreonam, and are susceptible to cefepime and carbapenems as well. Plasmid-mediated AmpC beta-lactamases have arisen through the transfer of chromosomal genes for the inducible AmpC beta-lactamase onto plasmids. All plasmid-mediated AmpC beta-lactamases have similar substrate profiles to the parental enzymes from which they appear to be derived. With one exception, plasmid-mediated AmpCs differ from chromosomal AmpCs in being uninducible. The National Committee for Clinical Laboratory Standards (NCCLS) has issued recommendations for ESBL screening and confirmation for isolates of E. coli, K. pneumoniae and K. oxytoca. No NCCLS recommendations exist for ESBLs detection and reporting for other organisms or for detecting plasmid-mediated AmpC beta-lactamases. High-level expression of AmpC may prevent recognition of an ESBL in species that produce a chromosomally encoded inducible AmpC beta-lactamase. AmpC-inducible species (e. g. Enterobacter spp. and C. freundii) can be recognized by cefoxitin/cefotaxime disk antagonism tests. Since clinical laboratories are first to encounter bacteria with new forms of antibiotic resistance, they need appropriate tools to recognize these bacteria, including trained staff with sufficient time and equipment to follow up important observations. Because bacterial pathogenes are constantly changing, training must be an ongoing process.

Enterobacteriaceae↗
PubMed2004

Postoperative endophthalmitis by Flavimonas oryzihabitans.

A 55-year-old man suffered from blurred vision of the left eye (visual acuity was counting fingers/5-10 cm) 8 days after undergoing cataract surgery. After thorough ophthalmologic examinations with gram-negative bacillus justified on smear of vitreous specimen, postoperative endophthalmitis (os) was impressed. Intravitreous injection of 1.0 mg of vancomycin, 0.4 mg of amikacin, and 0.4 mg of dexamethasone was given twice and vitreous fluid culture was also performed. However, the inflammatory condition was not well controlled. Because the results of vitreous fluid culture revealed Flavimonas oryzihabitans infection which is sensitive to piperacillin, we performed the 3rd intravitreous injection of 1.0 mg of piperacillin and 0.4 mg of dexamethasone. The inflammatory condition was under control and the visual acuity of left eye improved. For patients with ocular diseases, postoperative endophthalmitis by Flavimonas oryzihabitans is a rare condition. According to the results of this case, intravitreous injection of piperacillin was effective against the pathogen.

Cataract Extraction↗
PubMed1990

Ecological impact of antimicrobial prophylaxis on intestinal microflora in patients undergoing colorectal surgery.

During recent years the impact of different antimicrobial agents on the intestinal microflora in patients undergoing colorectal surgery has been investigated by our research group. Thus the effects on the microflora by parenteral administration of piperacillin, cefoxitin, cefbuperazone, moxalactam, aztreonam, imipenem, ampicillin + sulbactam, clindamycin, tinidazole, ciprofloxacin and ofloxacin have been studied. Pronounced changes were observed in the aerobic microflora in patients receiving ciprofloxacin and ofloxacin, in the anaerobic microflora in patients receiving clindamycin and tinidazole and in both the aerobic and anaerobic microflora in those patients receiving piperacillin, cefoxitin, cefbuperazone, moxalactam, aztreonam, imipenem and ampicillin + sulbactam. Postoperative infections were observed in patients receiving piperacillin (2), ampicillin + sulbactam (1), cefoxitin (1), aztreonam (3), tinidazole (6), clindamycin (5) and ofloxacin (5). In the patient groups receiving cefbuperazone, moxalactam, imipenem and ciprofloxacin, no postoperative infections occurred.

4-Quinolones↗
PubMed1986

[Activity of cefotetan against anaerobic bacteria].

We determined the susceptibility to antibiotics of 64 strains of obligate anaerobes. Tested bacterial strains were as follows: 28 Bacteroides fragilis, 22 Fusobacterium nucleatum, 10 Clostridium perfringens, and 4 Bacteroides bivius. Tested antibiotics were cefotetan, cefoxitin and piperacillin. Cefotaxime was tested against 20 Bacteroides fragilis strains. Bacteroides fragilis, which is the most resistant species, was susceptible to cefotetan, cefoxitin and piperacillin, with comparable MICs for these three drugs (0.5 to 16 micrograms/ml); cefotaxime was less effective (MICs = 0.5 to 128 micrograms/ml). Fusobacterium nucleatum and Clostridium perfringens were highly susceptible to cefotetan, cefoxitin and piperacillin.

Bacteroides↗
PubMed1988

Antimicrobial resistance in oral and colonic bacteroides.

Antimicrobial resistance in Bacteroides from oral and colonic flora influences the selection of antimicrobial therapy to treat infections involving these organisms. An antimicrobial susceptibility study of 49 clinical isolates of oral bacteroides to 9 drugs revealed high resistance rates for penicillin 53%, for cefaclor 45%, and for tetracycline 27%, while there were low rates (less than 10%) with cefoxitin, piperacillin, clindamycin, chloramphenicol and metronidazole. Review of our U.S. nationwide survey of the susceptibility of colonic bacteroides (Bacteroides fragilis group) reveals low resistance to clindamycin, cefoxitin, piperacillin, imipenem, chloramphenicol and metronidazole. However, the identification of clindamycin, clindamycin, cefoxitin, piperacillin, imipenem and chloramphenicol resistant isolates is worrisome. The mechanism of resistance and the resistant transfer mechanism to the different classes of drugs in the oral and colonic bacteroides are reviewed.

Bacteroides↗
PubMed1987

Stability of penicillins in total parenteral nutrient solution.

The stability of ticarcillin, mezlocillin, and piperacillin in total parenteral nutrient (TPN) solutions at concentrations commonly used in adults was determined. Each antibiotic was added separately to three different amino acids-dextrose TPN solutions in two concentrations: 10 and 20 mg/mL. Amino acids concentration ranged from 25 g/L to 50 g/L. Dextrose concentration ranged from 100 g/L to 350 g/L. Solutions were assayed for antibiotic concentration immediately after mixing (time 0) and at 4, 8, 24, and 48 hours by high-performance liquid chromatography. The effect of the added penicillins on the stability of amino acids and other TPN additives was not investigated. Mezlocillin and piperacillin 10 and 20 mg/mL exhibited stability in TPN solution at 24 hours. Ticarcillin was stable for 24 hours at a concentration of 10 mg/mL, but at 20 mg/mL it was unstable at all times tested. The three antibiotics demonstrated the same characteristic stability in all three TPN solutions, suggesting that the concentrations of dextrose and amino acids did not affect stability. Ticarcillin, mezlocillin, and piperacillin are stable for 24 hours in the TPN solutions studied.

Chromatography, High Pressure Liquid↗
PubMed1986

In vitro comparison of antiplatelet effects of beta-lactam penicillins.

beta-Lactam antibiotics have been shown to cause platelet dysfunction and bleeding in some patients. However, relative antiplatelet activity of various beta-lactams has remained controversial. Results of clinical studies have been variable because of the presence of underlying disease in the study patients, in addition to inherent difficulties of in vivo experimentation such as individual variations of drug metabolism and drug kinetics. Thus, we designed in vitro experiments to study the direct effect of penicillin G, carbenicillin, ticarcillin, mezlocillin, piperacillin, nafcillin, and azlocillin on platelets. Platelets obtained from normal volunteers were exposed in vitro for 15 minutes to increasing concentrations of the test penicillins (10.0, 12.5, 15.0, and 20.0 mmol/L), and the platelet aggregation response determined after the additional of adenosine diphosphate (2.5 to 5.0 mumol/L), epinephrine (0.1 X 10(-3) mol/L), thrombin (0.01 to 0.02 U/ml), and collagen (11.62 micrograms/ml). All tested penicillins inhibited platelet aggregation in a saturable dose-dependent manner that was reversible by platelet washing. Biostatistical comparison of inhibition of platelet aggregation demonstrated nafcillin to cause significantly more inhibition, followed by azlocillin, mezlocillin, and piperacillin as a group. Penicillin G, carbenicillin, and ticarcillin were the least inhibitory. The mean percent inhibition (epinephrine) at 20 mmol/L concentration was nafcillin 86.4%, mezlocillin 83.2%, piperacillin 80.3%, azlocillin 76.4%, ticarcillin 73.2%, carbenicillin 66.4%, and penicillin G 58.4% (overall P less than 0.001). We conclude that all penicillins tested in vitro inhibit platelet aggregation in normal individuals, but to varying degrees. The inhibitory response, which is most likely a membrane-related phenomenon, is dose dependent and reversible.

Adenosine Diphosphate↗
PubMed1985

[Susceptibility of Pseudomonas aeruginosa to aztreonam in comparison to other pseudomonas-active beta-lactam antibiotics and gentamicin].

The in vitro activity of aztreonam, a synthetic monobactam, was evaluated against 245 strains of Pseudomonas aeruginosa, 130 of them being recent clinical isolates from patients and 115 from hospital environment. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and bactericidal kinetics were determined. The possibility of resistance development in vitro was studied. Gentamicin, cefsulodin, piperacillin and azlocillin were used as comparative agents with known antipseudomonal activity. At a concentration of 8 mg/l 83.3%, at 16 mg/l 92% of the tested strains were susceptible to aztreonam. Thus, the activity of aztreonam against Pseudomonas aeruginosa is equivalent to that of gentamicin and cefsulodin and better than that of piperacillin and azlocillin in terms of resistance. Bactericidal kinetics with fourfold MIC, which is equivalent to MBC, are nearly identical for aztreonam, piperacillin and cefsulodin. In vitro induced resistance additionally causes increased resistance against the other beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1981

Antibacterial activity of moxalactam (LY-127935) compared with cefotaxime and other beta-lactam antibiotics against clinical isolates of enterobacteriacea and non-fermenters.

The in vitro activity of moxalactam, a new semisynthetic 1-oxa-beta-lactam, was compared to those cefotaxime, cefuroxime, cephalothin, piperacillin and tobramycin against more than 500 clinical isolates of Enterobacteriaceae and non-fermenters. The geometric mean MIC against 450 Enterobacteriaceae in microgram/ml was 0.09 for moxalactam, 0.08 for cefotaxime, 5.3 for cefuroxime, 22.9 for cephalothin, 3.5 for piperacillin and 0.72 for tobramycin. The geometric mean MIC in microgram/ml against 60 P. aeruginosa strains was 12.7 for moxalactam, 22.9 for cefotaxime, 6.8 for piperacillin, 1.5 for tobramycin and 2.9 for cefsoludin. The minimum inhibitory and the bactericidal concentrations of moxalactam were almost the same in most species. The effect of the inoculum on the bactericidal concentration was slight, between 10(3) and 10(7) CFU/ml for the E. coli and the Klebsiella strains. In isolates of S. marcescens and P. aeruginosa the bactericidal concentrations increased by 4 to 5 log2 and in isolates of P. mirabilis the increased by 9 log2 with the largest inoculum.

Anti-Bacterial Agents↗