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PubMed2003

Changing trends in bacteriology of burns in the burns unit, Delhi, India.

A retrospective study of bacterial isolates from the wounds of patients admitted to burns unit, was undertaken at Guru Tegh Bahadur Hospital, University College of Medical Sciences, Delhi, India, over a period of 5 years between July 1997 and April 2002. The study compared the results obtained with the previous 5 years data (June 1993-June 1997) from the same unit to determine the changing patterns and emerging trends of bacterial isolates and their antimicrobial susceptibilities. Pseudomonas species (31%) and Staphylococcus aureus (22%) were the most common pathogens followed by Klebsiella species (19%). Multi-drug resistant (MDR) Acinetobacter species (9%) have emerged as an important nosocomial pathogen in our burn unit. Most of the gram-negative isolates obtained were found to be multi-drug resistant and 61% of the tested isolates were extended spectrum beta-lactamase (ESBL) producers. Concomitant resistance to penicillin and aminoglycosides was observed in 61% of Enterococcus fecalis isolates. When compared with the results of previous 5 years (June 1993-June 1997) Pseudomonas spp. was still the commonest pathogen in the burns unit. However, isolation of this organism and other gram-negative organisms has decreased in comparison to previous years. The incidence of antimicrobial resistance has markedly increased over the past years resulting in limitation of therapeutic options.

Burn Units↗
PubMed1992

Influence of radiotherapy on intestinal microflora in cancer patients.

We investigated in 15 patients with carcinoma of the uterine cervix or endometrium, who were undergoing postoperative radiation therapy, the effects of different fractionated radiation exposures on counts of fecal bacteria, on the growth of Clostridium difficile and Clostridium perfringens enterotoxin production. We observed a generally significant decrease in intestinal microflora after the first radiation exposure, whereas at the end of radiotherapy all bacteria increased and reached basal values except Enterococcus faecium 1, lactobacilli and total anaerobes. In some patients we observed an overgrowth of some Clostridium spp. which were potential pathogens associated with clinical symptoms. We did not observe an influence of multiple radiations on C. perfringens enterotoxin fecal contents. We conclude that patients receiving radiotherapy may benefit from the intake of oral bacteriotherapy, i.e. live beneficial bacteria such as Bacillus subtilis at the beginning of the irradiation exposure.

Aged↗
PubMed2001

Comparative in vitro activity of ertapenem and 11 other antimicrobial agents against aerobic and anaerobic pathogens isolated from skin and soft tissue animal and human bite wound infections.

We studied the comparative in vitro activity of ertapenem, a new carbapenem, against 240 aerobic and 180 anaerobic recent clinical bite isolates using an agar dilution method and an inoculum of 10(4) cfu/spot for aerobes and 10(5) cfu/spot for anaerobes. Ertapenem inhibited 410/420 (98%) of the isolates tested at < or = 4 mg/L with only 4/5 Campylobacter gracilis and 1/3 Campylobacter rectus strains requiring . or = 16 mg/L for inhibition. Ertapenem was only moderately active (MIC 8 mg/L) against 4/6 Enterococcus faecalis and 1/11 Staphylococcus epidermidis strains. All Pasteurella multocida, Pasteurella septica, Pasteurella canis, Pasteurella dagmatis, Moraxella spp. and EF-4 isolates were inhibited at < or = 0.015 mg/L. MIC(90)s for other aerobic genera and species were as follows: Corynebacterium spp., 4 mg/L; Staphylococcus aureus, 0.25 mg/L; Staphylococcus epidermidis, 4 mg/L; other coagulasenegative staphylococci, 0.25 mg/L; Streptococcus milleri group, 0.5 mg/L; Eikenella corrodens, 0.03 mg/L; and Bergeyella zoohelcum, 0.5 mg/L. For anaerobes the range of MICs and MIC(90)s were: Prevotella ssp., < or = 0.015-0.5, 0.125 mg/L; Porphyromonas spp., < or = 0.015-0.03, 0.015 mg/L; Fusobacterium spp., 0.015-0.125, 0.03 mg/L; Bacteroides tectum, 0.03-0.125, 0.125 mg/L; and Peptostreptococcus spp., 0.01-2, 1 mg/L. Ertapenem showed excellent potency against the full range of animal and human bite wound pathogens.

Animals↗
PubMed1990

[Susceptibilities of clinical bacterial isolates to antimicrobial agents. A study mainly focused on imipenem. Reported by the Research Group for Testing Imipenem Susceptibility on Clinical Isolates].

This study was conducted to investigate susceptibilities of clinical bacterial isolates to imipenem (IPM) and other antibacterial agents at 64 hospital laboratories throughout Japan from September to December of 1988. In this study, identification and susceptibility testing were carried out at each laboratory and the tests were performed according to the disk dilution method recommended by NCCLS in which susceptibilities are classified into "S", "MS", "I" and "R". IPM showed markedly high in vitro activities against Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus faecalis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae, Serratia marcescens, Salmonella spp., Citrobacter freundii, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia rettgeri, Providencia stuartii, Acinetobacter calcoaceticus, Moraxella (Branhamella) catarrhalis, Alcaligenes spp., Peptococcus spp./Peptostreptococcus spp., Bacteroides fragilis and Bacteroides spp. IPM also had strong activities against Achromobacter xylosoxidans and Pseudomonas aeruginosa, but less active against Flavobacterium spp., E. faecium, coagulase-negative staphylococci (CNS), Staphylococcus aureus and Pseudomonas cepacia. In a study in which activities of IPM against bacteria isolated from different clinical sources were compared, differences in susceptibilities were observed among S. aureus, CNS, A. calcoaceticus and P. aeruginosa, but such differences were not apparent among S. pneumoniae, E. faecalis, H. influenzae, E. coli, K. pneumoniae, E. cloacae, C. freundii, S. marcescens or P. mirabilis.

Bacteria↗
PubMed1989

Comparative in vitro activities of piperacillin-tazobactam and ticarcillin-clavulanate.

The in vitro activities of ticarcillin, piperacillin, clavulanic acid, tazobactam, ticarcillin-clavulanate, and piperacillin-tazobactam against 819 bacterial isolates were compared. The two beta-lactamase inhibitors, clavulanic acid and tazobactam, had little useful antibacterial activity but enhanced the activities of the penicillins against beta-lactamase-producing strains of Haemophilus influenzae, Branhamella catarrhalis, and methicillin-susceptible Staphylococcus aureus; all strains were susceptible to both combinations. Both enzyme inhibitors also enhanced the activities of the penicillins against most strains of Escherichia coli, Klebsiella spp., Citrobacter diversus, Proteus spp., Providencia spp., and Bacteroides spp. and against occasional strains of Citrobacter freundii, Enterobacter spp., and Serratia marcescens. Clavulanic acid frequently enhanced the activity of ticarcillin against Xanthomonas maltophilia, and tazobactam frequently enhanced the activity of piperacillin against Morganella morganii. Enhancement was observed primarily with strains relatively resistant to the penicillins. In general, clavulanic acid was more effective than tazobactam in enhancing penicillin activity against Klebsiella spp., C. diversus, X. maltophilia, and Bacteroides spp., whereas tazobactam was more effective against Escherichia coli and Proteeae. There was little or no enhancement of activity against Enterococcus faecalis, Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas cepacia, or Acinetobacter anitratus. Clavulanic acid occasionally antagonized the activity of ticarcillin against ticarcillin-susceptible members of the family Enterobacteriaceae, but those strains were still considered susceptible to the combination. Tazobactam never antagonized the activity of piperacillin. In a direct comparison of the activities of ticarcillin-clavulanate and piperacillin-tazobactam, the two were equally active against H. influenzae, B. catarrhalis, and S. aureus; the latter was more active against E. faecalis. For relatively susceptible strains of members of the family Enterobacteriaceae, neither combination was predictably more active than the other, but relatively resistant strains were generally more susceptible to piperacillin-tazobactam. Piperacillin-tazobactam was more active than ticarcillin-clavulanate against A. hydrophila, P. aeruginosa, and P. cepacia, similar in activity against A. anitratus, and less active against X. maltophilia and Bacteroides spp.

Anti-Bacterial Agents↗
PubMed1993

Comparative in-vitro activities of the new quinolone, Bay y 3118, and ciprofloxacin, sparfloxacin, tosufloxacin, CI-960 and CI-990.

The in-vitro activity of the new quinolone, Bay y 3118, was compared with that of ciprofloxacin, tosufloxacin, sparfloxacin, CI-960 and CI-990 against 1640 isolates belonging to 117 bacterial species. Against members of the Enterobacteriaceae, Bay y 3118 was as active as CI-960 and CI-990, up to four-fold more active than ciprofloxacin and tosufloxacin and up to 16-fold more active than sparfloxacin. The majority of Enterobacteriaceae which were resistant to ciprofloxacin (MICs > or = 2 mg/L) were sensitive to Bay y 3118. With the exception of ciprofloxacin which was less active, the activities of Bay y 3118 and the other comparator compounds were similar against Acinetobacter baumannii, Acinetobacter genospecies 3 and Acinetobacter strain 84. Bay y 3118 inhibited Pseudomonas aeruginosa isolates at concentrations comparable with those of ciprofloxacin. However, non-aeruginosa Pseudomonas spp. were four times more susceptible to Bay y 3118 than to ciprofloxacin. All of the agents tested were equally active against Haemophilus, Moraxella, Neisseria and Bordetella spp. Against staphylococci, Bay y 3118 was the most active compound, followed jointly by CI-990, sparfloxacin, CI-960 and tosufloxacin, and then ciprofloxacin. Bay y 3118 remained highly active against Staphylococcus aureus strains resistant to ciprofloxacin; the MIC90 (0.5 mg/L) was 16-fold less than that of CI-990 and sparfloxacin, 32-fold less than that of CI-960 and 128-fold less than that of tosufloxacin and ciprofloxacin. Against haemolytic and non-haemolytic streptococci and Enterococcus faecalis, Bay y 3118 was two- to 16-fold more active than the other compounds. It had only moderate activity against Listeria spp., but this was superior to that of all the other compounds tested. Bay y 3118 was also the most active agent overall against anaerobic bacteria, although CI-960 and CI-990 had slightly better activity against Gardnerella vaginalis. It inhibited Mycobacterium spp. other than Mycobacterium tuberculosis (Mycobacterium kansasii, Mycobacterium scrofulaceum, Mycobacterium gordonae, Mycobacterium xenopi, Mycobacterium flavescens, Mycobacterium avium and Mycobacterium fortuitum) at concentrations < or = 0.06-4 mg/L and was between two- and 128-fold more active than the other compounds against these isolates; the two strains each of Mycobacterium terrae and Mycobacterium nonchromogenicum were resistant to Bay y 3118. In this study, Bay y 3118 was shown to be the most active and most broad-spectrum of the new quinolone and naphthyridine derivatives.

Anti-Infective Agents↗
PubMed1999

Ciprofloxacin in treatment of nosocomial meningitis in neonates and in infants: report of 12 cases and review.

Twelve cases of neonatal and infant nosocomial meningitis treated with intravenous ciprofloxacin in doses of 10 to 60 mg/kg/day are described. Four neonates were 21 to 28 days old and eight infants were 2 to 6 months old. Six presented with Gram-negative meningitis: Escherichia coli (2), Salmonella enteritidis (1), Acinetobacter calcoaceticus (1), two with two organisms, and (H. influenzae plus Staphylococcus epidermidis, Acinetobacter spp. plus S. epidermidis), and six were attributable to Gram-positive cocci (four S. aureus and two Enterococcus faecalis). Ten cases were cured. In two cases, reversible hydrocephalus appeared that responded to intraventricular punctures. In seven children, no neurologic sequellae appeared after a 2- to 4-year follow-up. One neonate had relapse of meningitis 3 months later and was ultimately cured, but developed a sequellae of psychomotoric retardation. Follow-up varied from 27 months to 10 years. Current published case reports from Medline on quinolone use in meningitis in neonates and infants are reviewed.

Anti-Infective Agents↗
PubMed2002

Bacterial enteropathogens and factors associated with seasonal episodes of gastroenteritis in Nsukka, Nigeria.

Each year, between April and October, many children of school age and some young adults in Nsukka, Nigeria suffer from gastroenteritis. The period covers the rainy season in this part of Africa, when manured farmland occasionally is flooded. In view of the number of people suffering diarrhoea and occasionally low-grade fever, it became necessary to investigate the nature of the bacterial agents responsible. Between April and October (1996-1998), 500 loose or watery stools were collected from patients, the ages of which ranged from one month to 31 years. Stools that contained parasites were excluded from the study. Samples were cultured on 5% blood agar and 1% egg-yolk agar (both containing 10 microg/mL ampicillin), MacConkey agar, Shigella Salmonella agar and in alkaline peptone water. Bacterial growths were identified using standard bacteriological procedures. Drinking water and some fruit and vegetables prevalent during this period of the year also were cultured. Of the 500 stool samples tested, 138 (27.6%) grew a range of organisms including Aeromonas hydrophila (65 [13%]), Salmonella spp. (55 [11%]), Shigella spp. (9 [1.8%]) and enteropathogenic Escherichia coli (9 [1.8%]). Drinking water and some vegetables grew Pseudomonas aeruginosa and Enterococcus faecalis, respectively. The highest isolation rate occurred during June and July, corresponding to the period of greatest flooding of arable land. Although no enteropathogens were isolated from the fruit and vegetables examined, they contained E. faecalis--an organism found in faeces. Our findings failed to explain why 72% of the samples grew no bacterial enteropathogens.

Adolescent↗
PubMed2003

Intestinal microflora in early infancy: composition and development.

The neonatal intestinal microbiota is a complex ecosystem composed of numerous genera, species and strains of bacteria. This enormous cell mass performs a variety of unique activities that affect both the colonic and systemic physiology. Its primary activities include nutritive, metabolic, immunological and protective functions. Most studies of infants have been based on faecal samples using the classical plating techniques with culturing on specific media. The limitations of these methods must be taken into account when evaluating the varying results of the different studies. The establishment of the gut microbial population is not strictly a succession in the ecological sense; it is rather a complex process influenced by microbial and host interactions and by external and internal factors. The climax intestinal flora is attained in successive stages. The foetal intestine is sterile and bathed in swallowed amniotic fluid. Following delivery, multiple different antigens challenge the intestine of the newborn. The maternal intestinal flora is a source of bacteria for the neonatal gut. The bacterial flora is usually heterogeneous during the first few days of life, independently of feeding habits. After the first week of life, a stable bacterial flora is usually established. In full-term infants a diet of breast milk induces the development of a flora rich in Bifidobacterium spp. Other obligate anaerobes, such as Clostridium spp. and Bacteroides spp., are more rarely isolated and also enterobacteria and enterococci are relatively few. During the corresponding period, formula-fed babies are often colonized by other anaerobes in addition to bifidobacteria and by facultatively anaerobic bacteria; the development of a "bifidus flora" is unusual. In other studies the presence of a consistent number of bifidobacteria in infants delivered in large urban hospitals has not been demonstrated, whether the babies were bottle fed or exclusively breastfed. The predominant faecal bacteria were coliforms and bacteroides. According to these studies, environmental factors may be more important than breastfeeding in gut colonization after delivery. Environmental factors are indeed extremely important for the intestinal colonization of infants born by caesarean section. In these infants, the establishment of a stable flora characterized by a low incidence of Bacteroides spp. and by the isolation of few other bacteria is consistently delayed. In extremely low-birthweight infants, hospitalization in neonatal intensive care units, characterized by prolonged antibiotic therapy, parenteral nutrition, delayed oral feedings and intubation seems to affect the composition of the intestinal microbiota. The gut is colonized by a small number of bacterial species; Lactobacillus and Bifidobacteria spp. are seldom, if ever, identified. According to the few studies so far performed, the predominant species are Enterococcus faecalis, E. coli, Enterobacter cloacae, Klebsiella pneumoniae, Staphylococcus epidermidis and Staphylococcus haemolyticus. Hygienic conditions and antimicrobial procedures strongly influence the intestinal colonization pattern.

Anti-Bacterial Agents↗
PubMed1991

[Antibacterial activity of ciprofloxacin against fresh clinical isolates from superficial suppurative foci].

The minimum inhibitory concentrations (MICs) of 5 drugs (ciprofloxacin (CPFX), and 4 drugs used as standard) were determined to investigate antibacterial potencies of CPFX against bacterial strains isolated in 1989 from superficial suppurative foci. The clinical isolates tested included 375 strains from 11 aerobic bacterial species, and 50 strains from 2 anerobic bacterial genera (group) for a total of 425 isolates. Interpreting MIC level distributions of these drugs as the expression of antibacterial potencies, the results are as follows. 1. When activities of new-quinolone antibiotics were tested, we found that, CPFX expressed far superior antibacterial potency to ofloxacin (OFLX) and norfloxacin (NFLX) against coagulase-negative staphylococci, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Pseudomonas aeruginosa and Peptostreptococcus spp., although the activity of CPFX against Bacteroides fragilis group was weaker than that of OFLX, and CPFX had similar activity against Staphylococcus aureus to OFLX. 2. In comparison to beta-lactam antibiotics, CPFX was inferior to amoxicillin (AMPC) against E. faecalis and inferior to AMPC and cefaclor (CCL) against Peptostreptococcus spp. Against all other bacterial species, however, CPFX expressed superior antibacterial potency to AMPC and CCL. 3. Scattered findings of low sensitivity or resistance to CPFX were observed among the S. aureus, E. faecalis, E. faecium, P. vulgaris, M. morganii, P. aeruginosa and B. fragilis (group) species, but with an exception of E. faecium, the incidence of resistance strains was low.

Amoxicillin↗
PubMed1996

[Increased antibiotic resistance of intestinal bacteria].

A survey of bacterial resistance rates in four intensive care units (ICU) at a Swedish university hospital showed an increase of ampicillin resistant enterococci from 3.2 percent 1993 to 17.7 percent 1994. This increase of ampicillin-resistant enterococci was due to an increase of Enterococcus faecium with chromosomal ampicillin resistance. The survey also showed a relative high level of cefalosporine resistance, at the ICUs, among Enterobacter spp and to some extent among Escherichia coli and Klebsiella spp. A simultaneously performed survey of all blood isolates from the four hospitals in the county revealed the same development of resistance but the resistance rates were lower compared with the ICUs. To reduce the spread of resistant bacterial isolates there is a need for decreased and optimized antibiotic consumption as well as isolation of patients infected with resistant isolates.

Ampicillin Resistance↗
PubMed1994

In vitro activities of two glycylcyclines.

The in vitro activities of two glycylcyclines, CL 329,998 and CL 331,002 (two new semisynthetic tetracyclines), were evaluated in comparison with those of tetracycline and other available oral antimicrobial agents. A total of 523 recent clinical isolates were studied, including strains resistant to tetracycline. Members of the family Enterobacteriaceae were generally > or = 16-fold more susceptible to the glycylcyclines than to tetracycline (although less difference was seen with Proteus spp.). Pseudomonas aeruginosa was modestly susceptible to both new compounds (MIC for 90% of strains tested [MIC90], 16 micrograms/ml). Tetracycline- and methicillin-susceptible and -resistant strains of Staphylococcus aureus were all susceptible to the glycylcyclines (MIC90 < or = 1 microgram/ml). Streptococci (including Streptococcus pneumoniae) and Enterococcus faecalis and Enterococcus faecium displayed a bimodal distribution of susceptibility to tetracycline yet were uniformly susceptible to the glycylcyclines (MIC90 < or = 0.25 microgram/ml). The glycylcyclines were highly potent against Neisseria, Moraxella, Haemophilus, and Bacteroides spp. (MIC90 < or = 0.5 microgram/ml). Strains of Chlamydia spp. (three C. trachomatis strains and one C. pneumoniae strain) were inhibited by < or = 0.25 microgram of CL 329,998 or CL 331,002 per ml. Two strains of Mycoplasma pneumoniae were inhibited by < or = 0.12 microgram of CL 331,002 per ml and by 1 microgram of CL 329,998 per ml. Mycobacterium tuberculosis and Mycobacterium avium were resistant to the two glycylcyclines (MIC > or = 8 micrograms/ml). These results indicate that the two glycylcyclines have potent in vitro activities against a wide range of clinically important pathogenic bacteria.

Bacteria↗
PubMedDate not supplied

Sulbactam/ampicillin versus metronidazole/gentamicin in the treatment of post-cesarean section endometritis.

Sixty-seven patients diagnosed with post-cesarean-section endometritis were studied in a prospective comparative randomized trial of sulbactam/ampicillin, a new beta-lactamase inhibitor drug combination, versus treatment with metronidazole/gentamicin. The success rate was 91% for each antibiotic regimen. Mycoplasma spp. or Ureaplasma spp. were isolated from all treatment failures. Endometrial cultures revealed 2.3 aerobes as well as anaerobes per patient, with Enterococcus faecalis, Bacteroides bivius, and Escherichia coli the most frequently reported bacterial isolates in 64, 40, and 28% of all patients, respectively. Positive blood cultures were noted in 11 (15%) patients with Mycoplasma sp. the most commonly found isolate (45.5%). Sulbactam/ampicillin appears to be safe and equally effective as a metronidazole/aminoglycoside drug regimen in the treatment of postpartum endometritis.

Adult↗
PubMed2000

Profiling of bacterial flora in gastric biopsies from patients with Helicobacter pylori-associated gastritis and histologically normal control individuals by temperature gradient gel electrophoresis and 16S rDNA sequence analysis.

The aim of this study was to establish bacterial profiles in gastric biopsy specimens from patients with Helicobacter pylori-associated gastritis by means of temporal temperature gradient gel electrophoresis (TTGE) of PCR-amplified 16S rDNA fragments. Specimens from eight patients with asymptomatic gastritis and five histologically normal controls revealed a Helicobacter-specific band in the TTGE profile with increased amounts of Helicobacter-specific DNA in the biopsies from most of the gastritis patients. DNA from other genera including Enterococcus, Pseudomonas, Streptococcus, Staphylococcus and Stomatococcus was also found in the stomach. In the absence of gastric inflammation, Helicobacter spp. appeared to be part of a complex, presumably indigenous microbial flora found in the biopsy specimens from the stomach.

Biopsy↗
PubMed1996

In vitro activities of U-100592 and U-100766, novel oxazolidinone antibacterial agents.

Oxazolidinones make up a relatively new class of antimicrobial agents which possess a unique mechanism of bacterial protein synthesis inhibition. U-100592 (S)-N-[[3-[3-fluoro-4-[4-(hydroxyacetyl)-1-piperazinyl]- phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide and U-100766 (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]- 2-oxo-5-oxazolidinyl]methyl]-acetamide are novel oxazolidinone analogs from a directed chemical modification program. MICs were determined for a variety of bacterial clinical isolates; the respective MICs of U-100592 and U-100766 at which 90% of isolates are inhibited were as follows: methicillin-susceptible Staphylococcus aureus, 4 and 4 micrograms/ml; methicillin-resistant S. aureus, 4 and 4 micrograms/ml; methicillin-susceptible Staphylococcus epidermidis, 2 and 2 micrograms/ml; methicillin-resistant S. epidermidis, 1 and 2 micrograms/ml; Enterococcus faecalis, 2 and 4 micrograms/ml; Enterococcus faecium, 2 and 4 micrograms/ml; Streptococcus pyogenes, 1 and 2 micrograms/ml; Streptococcus pneumoniae, 0.50 and 1 microgram/ml; Corynebacterium spp., 0.50 and 0.50 micrograms/ml; Moraxella catarrhalis, 4 and 4 micrograms/ml; Listeria monocytogenes, 8 and 2 micrograms/ml; and Bacteroides fragilis, 16 and 4 micrograms/ml. Most strains of Mycobacterium tuberculosis and the gram-positive anaerobes were inhibited in the range of 0.50 to 2 micrograms/ml. Enterococcal strains resistant to vancomycin (VanA, VanB, and VanC resistance phenotypes), pneumococcal strains resistant to penicillin, and M. tuberculosis strains resistant to common antitubercular agents (isoniazid, streptomycin, rifampin, ethionamide, and ethambutol) were not cross-resistant to the oxazolidinones. The presence of 10, 20, and 40% pooled human serum did not affect the antibacterial activities of the oxazolidinones. Time-kill studies demonstrated a bacteriostatic effect of the analogs against staphylococci and enterococci but a bactericidal effect against streptococci. The spontaneous mutation frequencies of S. aureus ATCC 29213 were <3.8 x 10(-10) and <8 x 10(-11) for U-100592 and U-100766, respectively. Serial transfer of three staphylococcal and two enterococcal strains on drug gradient plates produced no evidence of rapid resistance development. Thus, these new oxazolidinone analogs demonstrated in vitro antibacterial activities against a variety of clinically important human pathogens.

Acetamides↗
PubMed1991

In vitro activity of a new 'higher-lactam' antibacterial agent LY 193239.

In vitro activity of the new bicyclic pyrazolidinone LY 193239 (Eli Lilly) was evaluated against 52 clinical isolates of Haemophilus influenzae (4 were beta-lactamase producers), 32 Enterococcus faecalis, 14 Neisseria gonorrhoeae (1 beta-lactamase-positive) and 19 Neisseria meningitidis. Activity was best against Neisseria spp. and H. influenzae, including penicillinase-producing strains. Results of the time-kill study against a non-enzyme-mediated penicillin resistant strain of N. meningitidis indicate that exposure to an antibacterial concentration four times the minimal inhibitory concentration was bactericidal. E. faecalis was insensitive.

Bacteria↗
PubMed1993

Resistance to the antimicrobial agents of bacteria isolated from non-sterile pharmaceuticals.

The in vitro antimicrobial resistance of 391 bacterial strains isolated from 389 samples of oral and topical medicaments was examined. The numbers of strains isolated (and percentage of samples that present them) were: 234 Bacillus (32.1%), 79 Staphylococcus (13.6%), 46 Micrococcus (11.3%), nine Pseudomonas (1.5%), eight Acinetobacter (1.5%), five Enterococcus (1.2%), three Alcaligenes (0.8%), two Escherichia and Enterobacter (0.5%), one each Providencia, Serratia and Streptococcus (0.2%). Gram-positive bacteria were isolated from topical and oral medicaments and Gram-negative rods were detected only in topical medicaments. The 97.4% of Bacillus strains were resistant to lincomycin and B. cereus was resistant to beta-lactam and trimethoprim-sulphamethoxazole. Staphylococcus spp. showed a high percentage of resistant strains to ampicillin (51.8%), tetracycline (40.5%) and trimethoprim-sulphamethoxazole (48.1%). Staphylococcus epidermidis had the highest number of multiresistant strains. The 23.9% of Micrococcus strains were resistant to colistin. Enterococcus and Streptococcus strains showed multiresistance to penicillin G, aminoglycosides and erythromycin. The 61.5% of Gram-negative rod strains showed multiresistance to beta-lactam antibiotics and erythromycin; Pseudomonas spp. were the most resistant.

Bacillus↗
PubMed2000

Evaluation of the in vitro activity of 9 antimicrobials against bacterial strains isolated from patients in intensive care units in brazil: MYSTIC Antimicrobial Surveillance Program.

Multi-resistant bacterial strains are increasingly prevalent in hospital environments. Bacterial resistance is an important problem, especially for practitioners in intensive care units (ICUs) because of the selective pressure on the prevalent bacteria in these environments. The MYSTIC (Meropenem Yearly Susceptibility Test Information Collection) study has been monitoring the performance of carbapenems and other antibiotics in different hospitals for at least 3 years. The in vitro activities of meropenem, imipenem, ceftazidime, cefepime, cefotaxime, ciprofloxacin, piperacilin/tazobactam, gentamicin, and tobramycin were compared against 452 recent clinical aerobic isolates. The isolates consisted of 19 species of Gram-negative bacteria (n=290) including K. pneumoniae (n=49), E. coli (n=48), A. baumannii (n=47), Enterobacter spp. (n=41), and P. aeruginosa (n=33) and 9 species of Gram-positive bacteria (n=162) including Staphylococcus aureus (n=63), Enterococcus faecalis (n=22), Streptococcus pneumoniae (n=22) and coagulase negative Staphylococci (n=21). All isolates were collected from ICU patients. Minimal inhibitory concentrations (MICs) were determined by Etest methodology, using standardized and controlled procedures. Meropenem and imipenem showed the lowest MIC(90) for all species tested. Gram-negative isolates showed the following overall resistance percentages to the other 7 drugs: tobramycin (43.1%), cefotaxime (38.6%), gentamicin (34.1%), ceftazidime (31.7%), ciprofloxacin (25.5%), piperacillin/tazobactam (26.9%), and cefepime (18.6%). Carbapenems were the most active drugs overall and only P. aeruginosa presented some degree of resistance (18.2%). We also evaluated the production of extended spectrum beta-lactamase (ESBL) among all Enterobacteriaceae members (n=176) by Etest/ESBL strip. ESBL production was detected in 51 strains (29.0%). Among them, Klebsiella pneumoniae was the most prevalent at 59.2%, followed by Enterobacter spp. (19.5%) and E. coli (14.6%). The high level of resistance against several antimicrobials and the alarming rate of ESBL production may restrict therapeutic choice to the carbapenems in this selected group of patients.

Anti-Bacterial Agents↗