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PubMed1980

Antimicrobial activity of heparin.

Single clinical isolates of eight species of microorganisms were incubated in solutions of heparin and brain heart infusion broth at various concentrations to determine the possible antibacterial effect of heparin. At heparin concentrations ranging from 12.5 to 400 U/ml, the effect on Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Staphylococcus aureus, and S. epidermidis varied with brain heart infusion broth concentrations of 1.2 to 10% and inocula of 10(2) to 10(6) colony-forming units per ml; similar effects were not observed with Klebsiella pneumoniae, Enterobacter aerogenes, and Citrobacter spp. The minimal inhibitory concentrations of heparin for ten strains of each species were determined in 2.5% brain heart infusion broth with inocula of 10(4) colony-forming units per ml. All 10 isolates of S. aureus and all 10 of S. epidermidis were inhibited by heparin concentrations of 125 to 500 U/ml. Three E. coli, four P. aeruginosa, and nine C. albicans strains were inhibited by </=500 U of heparin per ml. None of the K. pneumoniae, E. aerogenes, Enterobacter cloacae, and Citrobacter spp. was inhibited by heparin at </=500 U/ml. Heparin inhibition of S. aureus in 2.5% brain heart infusion broth-500 U of heparin per ml could be quantitatively overcome by addition of magnesium, calcium, or magnesium and calcium. These data suggest that the growth of microorganisms from heparin-containing material may be suppressed.

Anti-Bacterial Agents↗

PubMed1993

Evaluation of the L-pyrrolidonyl-beta-naphthylamide hydrolysis test for the differentiation of members of the families Enterobacteriaceae and Vibrionaceae.

A simple, rapid, and inexpensive spot test incorporating the substrate pyrrolidonyl naphthylamide was used to examine pyrrolidonyl peptidase activity among 800 bacterial strains belonging to the families Enterobacteriaceae and Vibrionaceae. The pyrrolidonyl naphthylamide test was found to be particularly useful in separating Citrobacter spp. (100% positive) from Salmonella spp. (0.4% positive) and Escherichia coli (0% positive). Furthermore, it would appear to offer a safer alternative to the traditional potassium cyanide test for differentiating citrobacters from salmonellae.

Bacterial Typing Techniques↗

PubMed2000

Cost-effective and rapid presumptive identification of gram-negative bacilli in routine urine, pus, and stool cultures: evaluation of the use of CHROMagar orientation medium in conjunction with simple biochemical tests.

The algorithm for a new identification system was designed on the basis of colony color and morphology on CHROMagar Orientation medium in conjunction with simple biochemical tests such as indole (IND), lysine decarboxylase (LDC), and ornithine decarboxylase (ODC) utilization tests with gram-negative bacilli isolated from urine samples as well as pus, stool, and other clinical specimens by the following colony characteristics, biochemical reactions, and serological results: pinkish to red, IND positive (IND(+)), Escherichia coli; metallic blue, IND(+), LDC(+), and ODC negative (ODC(-)), Klebsiella oxytoca; IND(+), LDC(-), and ODC(+), Citrobacter diversus; IND(+) or IND(-), LDC(-), and ODC(-), Citrobacter freundii; IND(-), LDC(+), and ODC(+), Enterobacter aerogenes; IND(-), LDC(-), and ODC(+), Enterobacter cloacae; IND(-), LDC(+), and ODC(-), Klebsiella pneumoniae; diffuse brown and IND(+), Morganella morganii; IND(-), Proteus mirabilis; aqua blue, Serratia marcescens; bluish green and IND(+), Proteus vulgaris; transparent yellow-green, serology positive, Pseudomonas aeruginosa; clear and serology positive, Salmonella sp.; other colors and reactions, the organism was identified by the full identification methods. The accuracy and cost-effectiveness of this new system were prospectively evaluated. During an 8-month period, a total of 345 specimens yielded one or more gram-negative bacilli. A total of 472 gram-negative bacillus isolates were detected on CHROMagar Orientation medium. For 466 of the isolates (98.7%), no discrepancies in the results were obtained on the basis of the identification algorithm. The cost of identification of gram-negative bacilli during this period was reduced by about 70%. The results of this trial for the differentiation of the most commonly encountered gram-negative pathogens in clinical specimens with the new algorithm were favourable in that it permitted reliable detection and presumptive identification. In addition, this rapid identification system not only significantly reduced costs but it also improved the daily work flow within the clinical microbiology laboratory.

Agar↗

PubMed2002

BetalasEN: microdilution panel for identifying beta-lactamases present in isolates of Enterobacteriaceae.

A dried investigational use-only microdilution panel named betalasEN (a short named derived from the panel's purpose, to identify beta-lactamases in Enterobacteriaceae) containing 10 beta-lactam drugs with and without beta-lactamase inhibitors was developed to identify beta-lactamases among clinical isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter koseri, Citrobacter freundii group, Enterobacter spp., and Serratia marcescens. The MICs obtained with a collection of 383 organisms containing well-characterized beta-lactamases were used to develop numeric codes and logic pathways for computerized analysis of results. The resultant logic pathways and betalasEN panel were then used to test and identify beta-lactamases among 885 isolates of Enterobacteriaceae recovered in cultures obtained at six different hospital laboratories across the United States. beta-Lactamases present in 801 (90.5%) of the 885 isolates were identified by betalasEN by using the existing logic pathways and codes or after minor modifications were made to the existing codes. The 84 strains that gave codes that betalasEN could not identify were collected, reidentified, and retested by using betalasEN. Three strains had been misidentified, 54 strains gave different codes upon repeat testing that could be identified by betalasEN, and 27 strains repeated new codes. The beta-lactamases in these strains were identified, and the new codes were added to the betalasEN logic pathways. These results indicate that betalasEN can identify clinically important beta-lactamases among most isolates of Enterobacteriaceae. The results also show that good quality control and attention to proper performance of the tests are essential to the correct performance of betalasEN.

Anti-Bacterial Agents↗

PubMed2003

Characterization of clinical isolates of Enterobacteriaceae from Italy by the BD Phoenix extended-spectrum beta-lactamase detection method.

Production of extended-spectrum beta-lactamases (ESBLs) is an important mechanism of beta-lactam resistance in Enterobacteriaceae: Identification of ESBLs based on phenotypic tests is the strategy most commonly used in clinical microbiology laboratories. The Phoenix ESBL test (BD Diagnostic Systems, Sparks, Md.) is a recently developed automated system for detection of ESBL-producing gram-negative bacteria. An algorithm based on phenotypic responses to a panel of cephalosporins (ceftazidime plus clavulanic acid, ceftazidime, cefotaxime plus clavulanic acid, cefpodoxime, and ceftriaxone plus clavulanic acid) was used to test 510 clinical isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Providencia stuartii, Morganella morganii, Enterobacter aerogenes, Enterobacter cloacae, Serratia marcescens, Citrobacter freundii, and Citrobacter koseri. Of these isolates, 319 were identified as ESBL producers, and the remaining 191 were identified as non-ESBL producers based on the results of current phenotypic tests. Combined use of isoelectric focusing, PCR, and/or DNA sequencing demonstrated that 288 isolates possessed bla(TEM-1)- and/or bla(SHV-1)-derived genes, and 28 had a bla(CTX-M) gene. Among the 191 non-ESBL-producing isolates, 77 isolates produced an AmpC-type enzyme, 110 isolates possessed TEM-1, TEM-2, or SHV-1 beta-lactamases, and the remaining four isolates (all K. oxytoca strains) hyperproduced K1 chromosomal beta-lactamase. The Phoenix ESBL test system gave positive results for all the 319 ESBL-producing isolates and also for two of the four K1-hyperproducing isolates of K. oxytoca. Compared with the phenotypic tests and molecular analyses, the Phoenix system displayed 100% sensitivity and 98.9% specificity. These findings suggest that the Phoenix ESBL test can be a rapid and reliable method for laboratory detection of ESBL resistance in gram-negative bacteria.

Algorithms↗

PubMed1982

Comparative epidemiology of gentamicin-resistant enterobacteria: persistence of carriage and infection.

During a two-year period from January 1979, 260 patients have been involved in an outbreak of carriage and infection due to gentamicin-resistant enterobacteria. We have examined the duration of carriage of such enterobacteria and have compared the carriage of Klebsiella with that of other resistant enterobacteria. Carriage of gentamicin-resistant enterobacteria occurred most frequently and was least sporadic in the intestinal tract. Vaginal carriage was observed in 49 out of 68 patients tested and occurred more frequently in older patients. Oral carriage was noted in 36% of patients but was more sporadic than intestinal carriage. Rates of oral carriage were greater among moribund patients. Carriage at skin sites was related to their proximity to the perineum. Intestinal carriage of gentamicin-resistant Escherichia coli and Klebsiellae but not Klebsiella oxytoca nor Citrobacter persisted for long periods (half lives of 140 and 100 days respectively). Cessation of carriage of gentamicin-resistant Klebsiellae was due to loss of both the organism and its plasmid rather than a shedding of the plasmid. Chronic bacteriuria with gentamicin-resistant E coli and Klebsiellae (half life 180 days) but not Klebsiella oxytoca nor Citrobacter persisted for long periods.

Bacteriuria↗

PubMed1983

Identification of strains isolated as total and fecal coliforms and comparison of both groups as indicators of fecal pollution in tropical climates.

This study was undertaken to better characterize the groups of total coliforms (TC) and fecal coliforms (FC) and to evaluate both groups as indicators of fecal contamination of drinking well water in a tropical climate (The Ivory Coast, West Africa). Isolated colonies obtained as TC or FC on membrane filters were identified using the API-20E system. From the well water samples, 58 golden-green colonies with a metallic sheen isolated on Endo medium (TC) were identified as Escherichia coli (55%), Enterobacter (26%), Klebsiella (14%), Proteus (3%), and Citrobacter (2%). Among 132 colonies isolated on Endo medium as non-TC (not showing the characteristic golden metallic sheen), 10% were identified as E. coli. The 196 blue colonies isolated on M-FC medium at 44.5 degrees C (FC) were identified as E. coli (66%), Klebsiella (12%), Enterobacter (10%), Citrobacter (5%), Salmonella (3%), Serratia (3%), Proteus (2%), and Yersinia (0.5%). Among 24 nonblue colonies on M-FC medium, none were identified as E. coli. Of the colonies isolated from human feces, E. coli represents 92% of the TC and 89% of the FC. Although these results are limited, they tend to confirm the greater specificity of the fecal coliform technique over that of total coliform for the detection of fecal contamination of untreated well water. From the results presented here and the observations of other workers, it is suggested that the use of FC instead of TC should be considered as the method of choice for determining drinking water pollution of untreated groundwater supplies.

Enterobacteriaceae↗

PubMed2024

Investigation of in vitro susceptibility and resistance mechanisms to amikacin among diverse carbapenemase-producing Enterobacteriaceae.

OBJECTIVE: This study aims to assess the in vitro drug susceptibility of various Carbapenemase-Producing Enterobacteriaceae (CPE) genotypes and elucidate the underlying mechanisms of amikacin resistance. METHODS: A total of 72 unique CPE strains were collected from the Second Hospital of Jiaxing between 2019 and 2022, including 51 strains of Klebsiella pneumoniae, 11 strains of Escherichia coli, 6 strains of Enterobacter cloacae, 2 strains of Klebsiella aerogenes, 1 strain of Citrobacter freundii, and 1strain of Citrobacter werkmanii. Among these strains, 24 carried blaKPC gene, 20 carried blaNDM gene, 23 carried blaOXA-48-like gene, and 5 carried both blaKPC and blaNDM. We measured the in vitro activity of amikacin and other common antibiotics. Strains carrying blaOXA-48-like gene were selected for whole genome sequencing (WGS) via next-generation sequencing to identify genes related to antimicrobial resistance (AMR) and virulence factor (VF). RESULTS: Out of the 72 CPE strains tested, 41.7% exhibited resistance to amikacin. The drug resistance rates for K. pneumoniae, E. coli, and Enterobacter spp. were 51.0%, 27.3%, and 10.0%, respectively. The majority of the CPE strains (> 90%) displayed resistance to cephalosporins and carbapenems, while most of them were sensitive to polymyxin B and tigecycline (97.2% and 94.4%). The amikacin resistance rate was 100% for strains carrying blaOXA-48, 20.8% for those with blaKPC, 5.0% for those with blaNDM, and 20.0% for those with both blaKPC and blaNDM. These differences were statistically significant (P < 0.05). Through sequencing, we detected aminoglycoside resistance genes rmtF and aac(6')-Ib, VF genes iucABCD and rmpA2 in OXA-48-producing multidrug resistance and highly virulent strains. These genes were located on a IncFIB- and IncHI1B-type plasmid, respectively. Both plasmids were highly homologous to the plasmid from OXA-232 strains in Zhejiang province and Shanghai province. Integration of these resistance genes into the IncFIB plasmid, facilitated by the IS6 and/or Tn3 transposons, resulted in OXA232-producing K. pneumoniae with amikacin resistance. CONCLUSION: This study identified significant amikacin resistance in CPE strains, particularly in those carrying the blaOXA-48 gene. Resistance genes rmtF and aac(6')-Ib were identified on plasmids. These results highlight the need for careful monitoring of amikacin resistance.

Amikacin↗

PubMed2004

Intracerebral abscess in children: historical trends at Children's Hospital Boston.

OBJECTIVES: A previous study performed at Children's Hospital Boston describing the natural history of intracerebral abscess between 1945 and 1980 demonstrated a decline in mortality after 1970. This current study examines the occurrence of intracerebral abscess at Children's Hospital Boston between 1981 and 2000, inclusive, and compares the results with the previous study. Our objectives were to determine whether there had been a change in the predisposing factors, whether there were changes in the microbiology of intracerebral abscesses, and whether mortality rate had continued to decline. METHODS: To ensure that all occurrences of intracerebral abscess treated at Children's Hospital Boston between 1981 and 2000 were identified, we searched 4 separately maintained databases for the keywords "brain" or "abscess" or the International Classification of Diseases, Ninth Revision code 324.x. This search yielded the names of 386 patients. Of these 386 patients, a solitary intracerebral abscess or multiple noncontiguous intracerebral abscesses could be confirmed in 54 patients on the basis of cranial imaging (computed tomography or magnetic resonance imaging) or autopsy reports. The complete retrospective review of the medical records of these 54 patients constitutes the basis for this study. RESULTS: Congenital heart disease was the most common predisposing factor during both eras. Compared with the previous era, important historical trends identified include a reduction in the number of abscesses that occurred in the settings of sinus or otitic infection (11% during 1981-2000 vs 26% during 1945-1980), an increase in number of intracranial abscesses in infants (18% vs 7%) and in the setting of immunosuppression (16% vs 1%), an increase in the number of children who were treated with antibiotics alone (22% vs 1%), a stable overall mortality rate (24% vs 27%), and the identification of Citrobacter and fungus as causes of intracranial abscess not observed during the previous era of 1945-1980. Citrobacter was observed only during the neonatal period. Fungi were the causative organisms predominantly in the setting of immunosuppression. CONCLUSIONS: Intracerebral abscess in children continues to be associated with high rates of neurologic impairment and death. Because earlier detection may reduce morbidity and mortality, intracranial abscess should be considered when evaluating children with new-onset neurologic signs or symptoms, especially in children who have acute immunosuppression and disseminated fungal disease or fungemia.

Adolescent↗

PubMed1988

Activity of cefotaxime and amikacin against 14,272 gram-negative bacteria from clinical samples in the period 1980 to 1985.

The sensitivity to cefotaxime and amikacin of 14,272 Gram-negative bacilli (Enterobacteriaceae and non-fermenting Gram-negative bacilli) isolated from clinical samples was studied during the period 1980 to 1985. The minimum inhibitory concentration (MIC) was determined by means of diffusion in agar. Strains were considered resistant to cefotaxime and amikacin if the MIC values were greater than 16 mg/L and greater than 8 mg/L, respectively. The MIC90 reached the critical value for cefotaxime in the case of Citrobacter spp., Escherichia coli, Klebsiella spp., Proteus mirabilis, Salmonella spp. and Shigella spp., and for amikacin in the case of Citrobacter spp., Enterobacter spp., E. coli, Klebsiella spp., P. mirabilis, Proteus vulgaris, Salmonella spp. and Serratia spp. Only Shigella spp. were sensitive to cefotaxime but not to amikacin, and only strains of Enterobacter spp. and Serratia spp. were sensitive to amikacin but not to cefotaxime.

Amikacin↗

PubMedDate not supplied

[Bacteriologic examination of gallbladder contents].

INTRODUCTION: Acute calculous (obstructive) cholecystitis develops as a consequence of cystic obstruction and obstruction of bile flow into choledochus. Most often it is a result of impacted gallstones in Hartman's pouch or the cystic duct. Their direct pressure on gallbladder mucosa causes ischemia, necrosis and ulceration with consequential wall edema and obstructed venous flow. This mechanism is further increasing and spreading the inflammatory process. Ulcerations may be that extensive, that mucosa is highly recognizable on the microscopic preparation. Leukocyte infiltration of all segments occurs. Results of necrosis are as follows: perforation with pericholecystic abscess formation, fistulization or biliary peritonitis. AIM: The aim of this investigation was to use microbial sensitivity tests in order to establish possibilities of antibiotic therapy in patients with acute cholecystitis. MATERIAL AND METHODS: Using random sampling a total of 240 patients with acute cholecystitis were included in the investigation. They were all treated at the Clinic of Abdominal and Endocrine Surgery of the Clinical Center Novi Sad in the period 1997-1999. All patients underwent bacteriological examination and were coherent in regard to sex and age. Microbial sensitivity tests analyzed two groups of bacteria: Group I: Escherichia coli, Klebsiella and Staphylococcus and Group II: other isolated bacteria (Citrobacter, Enterobacter, Enterococcus, Proteus, Pseudomonas, Serratia and Streptococcus). RESULTS: In our material Escherichia coli was isolated in most patients--32 (55.17%), Klebsiella and Staphylococcus in 6 (10.34%) patients and Streptococcus in 4 (6.90%), whereas other bacteria were infrequent (Citrobacter and Serratia in 3.45%, Enterobacter, Proteus and Pseudomonas in 1.75%). Thus, E. coli, Klebsiella and Staphylococcus were established in 75.85% of bacteriologic findings, and all the rest in 24.15%. Assessment regarding premedication with antibiotics started with an assumption that cholecystitis was caused by one of the bacteria isolated in 75% of cases. That is why antibiotics should be given prior to surgery, primarily those to which these bacteria are susceptible in more than 95% of cases. CONCLUSIONS: E. coli, Klebsiella and Staphylococcus participate with 75.85% of all bacteriologic findings, whereas all the others make 24.15%; Amikacin, Cefalexin, Ceftriaxone, Ofloxacin and Pefloxacin are recommended in premedication; considering the fact that new generation antibiotics have not been tested yet, they were not taken into consideration for this study.

Acute Disease↗

PubMed2006

Comparative analysis of a modified ecolite method, the colicomplete method, and a most-probable-number method for detecting Escherichia coli in orange juice.

The Ecolite High Volume Juice (HVJ) presence-absence method for a 10-ml juice sample was compared with the U.S. Food and Drug Administration Bacteriological Analytical Manual most-probable-number (MPN) method for analysis of artificially contaminated orange juices. Samples were added to Ecolite-HVJ medium and incubated at 35 degrees C for 24 to 48 h. Fluorescent blue results were positive for glucuronidase- and galactosidase-producing microorganisms, specifically indicative of about 94% of Escherichia coli strains. Four strains of E. coli were added to juices at concentrations of 0.21 to 6.8 CFU/ ml. Mixtures of enteric bacteria (Enterobacter plus Klebsiella, Citrobacter plus Proteus, or Hafnia plus Citrobacter plus Enterobacter) were added to simulate background flora. Three orange juice types were evaluated (n = 10) with and without the addition of the E. coli strains. Ecolite-HVJ produced 90 of 90 (10 of 10 samples of three juice types, each inoculated with three different E. coli strains) positive (blue-fluorescent) results with artificially contaminated E. coli that had MPN concentrations of <0.3 to 9.3 CFU/ml. Ten of 30 E. coli ATCC 11229 samples with MPN concentrations of <0.3 CFU/ml were identified as positive with Ecolite-HVJ. Isolated colonies recovered from positive Ecolite-HVJ samples were confirmed biochemically as E. coli. Thirty (10 samples each of three juice types) negative (not fluorescent) results were obtained for samples contaminated with only enteric bacteria and for uninoculated control samples. A juice manufacturer evaluated citrus juice production with both the Ecolite-HVJ and Colicomplete methods and recorded identical negative results for 95 20-ml samples and identical positive results for 5 20-ml samples artificially contaminated with E. coli. The Ecolite-HVJ method requires no preenrichment and subsequent transfer steps, which makes it a simple and easy method for use by juice producers.

Beverages↗

PubMed1999

[A consideration on the results of nationwide surveillance of antimicrobial susceptibilities--gram-negative bacilli].

The results of the semi-annual nationwide surveillance of antimicrobial susceptibilities, conducted by the Japanese Ministry of Health and Welfare during the period of January 1993 to July 1995, were analyzed for typical Gram-negative bacilli in the purpose of provision of an index for antimicrobial selection. During these 3 years, Escherichia coli, Citrobacter freundii, Enterobacter aerogenes and Proteus mirabilis showed slightly increasing tendency in susceptibility to fosfomycin (FOM) and Citrobacter freundii. Klebsiella pneumoniae and Enterobacter aerogenes showed slightly increasing tendency to minocycline (MINO). While Haemophilus influenzae and Haemophilus parainfluenzae showed slightly decreasing tendency to cefmetazole (CMZ). However, these annual changes were almost negligible. Generally, these microorganisms showed relatively good susceptibilities, every year, to the principal antimicrobial agents being approved for use against Gram-negative bacilli. However, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens and Pseudomonas aeruginosa showed tendencies of decreased susceptibility to some of the antimicrobial agents. On the other hand, sulfamethoxazole-trimethoprim (ST), CMZ, latamoxef (LMOX), gentamicin (GM) and amikacin (AMK) showed good activities against some of the Gram-negative bacilli to which no indications are approved. In conclusion, bedside the identification of the causative microorganisms and the performance of antimicrobial susceptibility testing, such analyses (graphics of susceptibility tendency of clinical isolates to variety of antimicrobial agents) could be used as an index for selection of antimicrobial agents, when emergent and urgent selection of antimicrobial agents is necessary.

Aminoglycosides↗

PubMed2000

Prevalence of bacterial pathogens and susceptibility patterns from clinical sources in Trinidad.

During a 12-month period (January-December, 1997), bacterial isolates of specimens from in-patients and out-patients of the Eric Williams Medical Sciences Complex (EWMSC) were reviewed. A total of 3,513 specimens were processed, 43.1% from in-patients and 56.9% from out-patients. Of the 3,513 specimens, 1129 (32.1%) yielded positive cultures. Micro-organisms from wounds, sputum and genital tract accounted for 90.2%, 51.5% and 31.8%, respectively, of all isolates. E coli (17.4%) and Enterococci (12.2%) were the predominant isolates and were also the major pathogens from blood stream infections, 25.8% and 18.2%, respectively, followed by P aeruginosa, 15.2%. High levels of resistance were seen to ampicillin, augmentin (amoxicillin-clavulanic acid) and tetracycline. The most effective antibiotics were ceftazidime (no resistance in E coli Citrobacter spp, non-typhoidal Salmonella and Group B streptococci, 63.2% resistance in Acinetobacter spp, 15.2% in Enterobacter spp, 17.4% in Klebsiella spp.], gentamicin [no resistance in Enterobacter and Citrobacter spp, and 89.5% in Acinetobacter spp), erythromycin (no resistance in Groups A and B streptococci, 85.1% in S aureus and S pneumoniae). The spectrum of isolates will provide clinicians with data on which to base their "best guess" aetiologic agent and choice of antibiotics when faced with infectious diseases in areas where laboratory assistance is not readily available.

Bacterial Infections↗

PubMed2000

[Multicenter evaluation of the antimicrobial activity in vitro for six broad-spectrum beta-lactams in China using the E-test method].

OBJECTIVE: To investigate the in vitro activities of cefepime and other 5 beta-lactam antimicrobial agents against 937 strains isolated from 10 teaching hospitals in different geographical areas in China during the early 1998. METHODS: The MIC values of cefepime, ceftazidime, ceftriaxone, imipenem, cefoperazone/sulbactum, and piperacillin against 937 isolates were tested by a gradient concentration method (E-test((R)); AB Biodisk Co.). RESULTS: Quality control isolates were tested in all working processes. MIC values of 96.5% (829/859 times) of quality assurance tests were within expected ranges of NCCLS. Only imipenem and cefepime could inhibit 90% of enterobacter and citrobacter strains, Cefepime were significantly more active than 3rd Generation cephalosporins in enterobacter and citrobacter strains, and little better active than E. coli and Klebsiella spp. (98%, 95% susceptibility). All tested antimicrobial excluding ceftazidime had very high activity to oxacillin susceptible Staphylococci (95% approximately 100% susceptibility). cefepime, ceftazidime, imipenem, and cefoperazone/sulbactum had similar activity to Pseudomonas aeruginosa (83% approximately 79% susceptibility). Both imipenem and cefoperazone/ sulbactum were very active to Acinetobacter spp. (97%, 89% susceptibility). CONCLUSION: The rank order of activity of the six tested agents is imipenem (97% Susceptible) > cefepime (89%) > cefoperazone/sulbactum (86%) > ceftazidime (76%) > ceftraixone (67%) > piperacillin (57%). The data are helpful to guide empiric therapy with beta-lactams in China.

Anti-Bacterial Agents↗

PubMed2002

[Yearly changes in antibacterial activities of cefozopran against various clinical isolates between 1996 and 2000--II. Gram-negative bacteria].

The in vitro antibacterial activities of cefozopran (CZOP), an agent of cephems, against various clinical isolates obtained between 1996 and 2000 were yearly evaluated and compared with those of other cephems, oxacephems, and carbapenems. Thirty-two species 2,697 strains of Gram-negative bacteria were isolated from the clinical materials annually collected from January to December, and consisted of Moraxella subgenus Branhamella catarrhalis (n = 125), Escherichia coli (n = 250), Citrobacter freundii (n = 153), Citrobacter koseri (n = 97), Klebsiella pneumoniae (n = 150), Klebsiella oxytoca (n = 100), Enterobacter aerogenes (n = 50), Enterobacter cloacae (n = 125), Serratia marcescens (n = 153), Proteus mirabillis (n = 103), Proteus vulgaris (n = 77), Morganella morganii (n = 141), Providencia spp. (P. alcalifaciens, P. rettgeri, P. stuartii; n = 154), Pseudomonas aeruginosa (n = 211), Pseudomonas putida (n = 49), Burkholderia cepacia (n = 102), Stenotrophomonas maltophilia (n = 101), Haemophilus influenzae (n = 210), Acinetobactor baumannii (n = 63), Acinetobactor Iwoffii (n = 30), Bacteroides fragilis group (B. fragilis, B. vulgatus, B. distasonis, B. ovatus, B. thetaiotaomicron; n = 129), and Prevotella spp. (P. melaninogenica, P. intermedia, P. bivia, P. oralis, P. denticola; n = 124). CZOP possessed stable antibacterial activities against M. (B.) catarrhalis, E. coli, C. freundii, C. koseri, K. pneumoniae, K. oxytoca, E. aerogenes, E. cloacae, S. marcescens, P. mirabilis, P. vulgaris, M. morganii, Providencia spp., P. aeruginosa, and A. lowffii throughout 5 years. The MIC90 of CZOP against those strains were consistent with those obtained from the studies performed until the new drug application approval. On the other hand, the MIC90 of CZOP against H. influenzae yearly obviously increased with approximately 65-time difference during study period. The MIC90 of cefpirome, cefepime, and flomoxef against H. influenzae also yearly tended to rise. The present results demonstrated that CZOP had maintained the antibacterial activity against almost Gram-negative strains tested. However, the decrease in the antibacterial activity of CZOP against H. influenzae was suggested.

Carbapenems↗

PubMed2003

[Continuous surveillance of antimicrobial resistance among nosocomial gram-negative bacilli from intensive care units in China].

OBJECTIVE: To investigate the change of antimicrobial resistance among nosocomial gram-negative bacilli, especially those of Enterobacteriaceae isolated from intensive care units from 1994 to 2001 in China. METHODS: E test was made to determine the minimal inhibitory concentrations (MIC) of 10 279 isolates of gram-negative bacilli (including 5 829 strains of bacilli of Enterobacteriaceae) from 32 hospitals in China from 1994 to 2001. RESULTS: The most common pathogens were Pseudomonas aeruginosa; Escherichia coli, Klebsiella spp, Acinetobacter spp. Enterobacter spp, and Stenotrophomonas maltophilia. The most common pathogens in respiratory tract specimens were Pseudomonas aeruginosa (25%), Klebsiella pneumoniae (18%), and Acinetobacter baumanni (11%). The most common pathogens in blood and urine specimens were Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The antibiotic remaining the most active against all of the gram-negative bacilli for 7 years was imipenem (with a susceptibility rate of 87%), followed by cefoperazone/sulbactam (however, with a susceptibility rate decreasing from 86% to 75%), amikacin (75%), ceftazidime (73%), cefepime (72%), and piperacillin/tazobactam (71%). The susceptibility rate of Escherichia coli Klebsiella pneumoniae to imipenem remained 98% with a MIC(90) of 0.5 micro g/ml during the 7 years, much higher than those to amikacin (84%), ceftazidime (83%), cefoperazone/sulbactam (83%), piperacillin/tazobactam (80%), and cefepime (80%). The susceptibility rate of these two species to cefoperazone/sulbactam decreased from 90% in 1996 to 74% in 2001. While the susceptibility to cefotaxime and ceftriaxone decreased from 82% to 57%. The susceptibility rate of Escherichia coli to ciprofloxacin decreased from 54% to 25% and that of Klebsiella pneumoniae to ciprofloxacin decreased from 90% to 75%. The prevalence of extended spectrum beta-lactamases in these two species increased from 11% in 1994 to 34% in 2001. The most active antibiotics against Enterobacter cloacae were imipenem, cefepime, amikacin with the susceptible rates of 95%, 76%, and 70%, respectively; the susceptibility rates of Citrobacter freundii to imipenem, cefepime, amikacin, and cefoperazone/sulbactam were 94%, 80%, 80%, and 78% respectively. Only 40% approximately 60% isolates of Enterobacter cloacae and Citrobacter freundii were susceptible to third-generation cephalosporins. CONCLUSION: Imipenem remains highly active against Enterobacteriaceae, but the activities of other antibiotics have decreased in recent years.

Anti-Bacterial Agents↗

PubMed1992

[Antibacterial activities of sisomicin against fresh clinical isolates].

To investigate antibacterial activities of sisomicin (SISO), MICs of SISO as well as other aminoglycosides (AGs) were determined against many clinical isolates which were obtained in 1991. Results are summarized below: 1. No SISO-resistant strains were observed among isolates of Escherichia coli, Citrobacter diversus, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Proteus mirabilis and Morganella morganii. 2. In comparison with the results of our previous study against isolates obtained in 1986, the rate of methicillin-resistant Staphylococcus aureus (MRSA) was higher, and SISO-resistant strains were observed at a high rate among the MRSA. Also, SISO-resistant strains of Serratia marcescens increased. However, the rate of SISO-resistant strains of Pseudomonas aeruginosa decreased, and among Citrobacter freundii, Enterobacter cloacae and Proteus vulgaris, SISO-resistant strains did not increase over the years. 3. MICs of SISO against Providencia rettgeri and Providencia stuartii were high, suggesting that antibacterial activities of SISO was weak against genus Providencia. 4. For comparison, according to MICs of ofloxacin and imipenem, new quinolone-resistant strains were observed at a high rate among various organisms, and carbapenem-resistant strains were observed at a high rate among S. marcescens and P. aeruginosa. 5. SISO is still one of the useful AGs in the 1990's since it maintains its strong antibacterial activities against most clinical isolates obtained in recent years and its potential as a combination drug with beta-lactams is being reported.

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