Antimicrobial activity of imipenem against 1386 clinical isolates

1386 isolates from clinical specimens were tested against imipenem by disc agar diffusion. The bacteria used in this study consisted of Escherichia coli, Enterobacter aerogenes, E. agglomerans, E. cloacae, Klebsiella pneumoniae, K. oxytoca, K. ozanae, Proteus mirabilis, P. vulgaris, Providencia stuartii, P. rettgeri, Acinetobacter calcoaceticus, Citrobacter diversus, C. freundii, Morganella morganii, Serratia liquefaciens, S. marcescens, Hafnia alvei, Aeromonas hydrophila, Pseudomonas aeruginosa, P. cepacia, P. maltophila, P. fluorescens, Staphylococcus aureus, S. epidermidis, S. saprophyticus, pneumococcus, Lancefield group A, B and D streptococci, viridans streptococci, diphtheroids and Bacillus species. In vitro activity of imipenem was compared with the following antibiotics: ampicillin, amikacin, carbenicillin, cefoperazone, cefoxitin, cephalothin, chloramphenicol, clindamycin, colistin, erythromycin, gentamicin, methicillin, penicillin, tetracycline, tobramycin, trimethoprim-sulfamethoxazole and vancomycin. Of the 819 strains of Enterobacteriaceae tested, 99.5% were susceptible to imipenem. Ninety-seven percent strains of P. aeruginosa were also susceptible to imipenem. All the 161 isolates of S. aureus and 116 of the 117 isolates of enterococci exhibited in vitro susceptibility to this antibiotic. All gram positive bacteria tested were inhibited by imipenem except 28% isolates of S. epidermidis and 5% isolates of S. agalactiae.     

Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2004

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 907 strains of Gram-positive bacteria, 1790 strains of Gram-negative bacteria, and 192 strains of anaerobic bacteria obtained from 30 medical institutions during 2004 was measured. The results were as follows; 1. MIC90 of MEPM for almost all of enterobacteriaceae and Haemophilus influenzae were 4-fold to 32-fold lower than those of other carbapenems. MEPM was more active than other carbapenem antibiotics against Gram-negative bacteria, especially against enterobacteriaceae and H. influenzae. MEPM were active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus. 2. As for Pseudomonas aeruginosa, imipenem (IPM) showed high cross-resistant rate againt meropenem-resistant P. aeruginosa (87.9%). MEPM showed low cross-resistant rate both againt IPM-resistant P. aeruginosa (49.2%) and ciprofloxacin-resistant P. aeruginosa (38.0%). 3. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 3.1% (4 strains) in Escherichia coli, 8.0% (2 strains) in Citrobacter koseri, 2.5% (3 strains) in Klebsiella pneumoniae, 2.5% (2 strains) in Enterobacter cloacae, 0.9% (1 strains) in Serratia marcescens, and 2.2% (2 strains) in Proteus mirabilis. The proportion of metallo-beta-lactamase strains was 1.6% (5 strains) in P. aeruginosa. 4. Of all species tested, Peptostreptococcus spp. was the only species, which MIC90 of MEPM was more than 4-fold higher than that in our previous study using clinical isolates during 2002 (0.25 microg/ml --> 1 microg/ml). Therefore, there is almost no siginificant decrease in susceptibility of clinical isolates to meropenem. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem at present, 9 years after available for commercial use.     

The resistance of recent clinical isolates against isepamycin, other aminoglycosides and injectable beta-lactams

Clinical isolates collected from clinical facilities across Japan in 1998 were tested against five aminoglycosides and three beta-lactams. The resistance of 50 strains each of methicillin sensitive Staphylococcus aureus, methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter sp., Serratia sp., Pseudomonas aeruginosa and Proteus sp. (P. mirabilis 25 strains and P. vulgaris 25 strains) to the aminoglycosides isepamicin (ISP), amikacin (AMK), gentamicin, tobramycin and dibekacin, and to the beta-lactams imipenem, ceftazidime and piperacillin (all three known to be effective against P. aeruginosa) were investigated using a micro liquid dilution method with the following results: 1. ISP was effective against all strains except for 14% of MRSA, 2% of Proteus sp., and 4% of P. aeruginosa. 2. Six strains of MRSA were resistant to all eight drugs; however, in these cases ISP exhibited a relatively low minimum inhibitory concentration (MIC) compared to the other compounds. 3. Four strains of MRSA were resistant to all drugs except ISP. MRSA was the only isolate to demonstrate a resistance to seven or more drugs. 4. Twenty-one strains of MRSA and 1 strain of P. aeruginosa were resistant to six drugs; however, all of these were susceptible to both ISP and AMK. 5. Against all strains tested, ISP generally exhibited a lower MIC compared to AMK. These results suggest that, even ten years after its entering the market, ISP is still an aminoglycoside having a high anti-bacterial activity against a wide range of clinical isolates.     

In vitro antibacterial activity of FK482, a new orally active cephalosporin

FK482 is a new orally active cephem antibiotic which offers some advantages over the commercially available oral beta-lactam antibiotics. It displayed a broad spectrum of activity in vitro against stock strains of Gram-positive and Gram-negative aerobes and anaerobes. FK482 was more active in vitro than cefixime (CFIX), cefaclor (CCL) or cephalexin (CEX) against clinical isolates of Gram-positive organisms such as methicillin-sensitive Staphylococcus aureus, coagulase-negative Staphylococci including Staphylococcus epidermidis and strains of the Streptococcus group. Moderate activity was found against methicillin-resistant S. aureus and Enterococcus faecalis. Against clinical isolates of many Gram-negative species, including opportunistic pathogens, FK482 had good in vitro activity similar or slightly inferior to that of CFIX but superior to that of CCL or CEX. However, it was clearly inferior to CFIX in activity against Serratia marcescens, and was inactive against Pseudomonas aeruginosa. Strains of S. aureus resistant to methicillin were moderately susceptible to FK482. All tested strains of Klebsiella pneumoniae resistant to CCL and CEX were susceptible to FK482, as were all the strains of Escherichia coli, Proteus mirabilis, Haemophilus influenzae and Branhamella catarrhalis resistant to amoxicillin (AMPC). FK482, like CFIX, was relatively stable to all type of beta-lactamases except Bacteroides fragilis and its stability was superior to that of CCL or CEX. The antibacterial activity of FK482 against CSH2 strains containing ampicillin-resistance plasmids was not affected by the presence of the ampicillin resistance determinants. FK482 showed higher affinity for the penicillin-binding proteins (PBPs) (3, 2 and 1) of S. aureus than did CFIX, CCL and CEX. FK482 also showed very high affinity for the PBPs (2 and 3) of E. faecalis and PBPs (3, 1a, 4, 2 and 1 bs) of E. coli. The bactericidal activity of FK482 against S. aureus was almost as strong as that of AMPC and superior to that of CCL or CEX. Against Gram-negative bacteria such as E. coli, K. pneumoniae and P. mirabilis, FK482 was similar to CFIX and superior to CCL and CEX in bactericidal activity.     

Susceptibilities of clinical isolates to antibacterial agents. Focusing mainly on ofloxacin (first report). Reported by the Research Group for Testing Ofloxacin Susceptibility of Clinical Isolates

Susceptibility tests were carried out on a variety of clinically isolated pathogens using the susceptibility disc method at 197 hospitals in Japan between May, 1985 through March, 1986. These tests were organized by the Research Group for Testing Ofloxacin Susceptibility on Clinical Isolates, and the results were statistically analyzed. This paper describes a comparison of susceptibilities of clinical isolates including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pneumoniae, Neisseria gonorrhoeae, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Citrobacter freundii, Klebsiella pneumoniae subsp. pneumoniae, Proteus mirabilis, Morganella morganii, Serratia marcescens, Haemophilus influenzae, Pseudomonas aeruginosa, Acinetobacter calcoaceticus, Acinetobacter sp. and Campylobacter jejuni to ofloxacin (OFLX) and conventional antibacterial drugs. The results obtained were summarized as follows. 1. OFLX showed strong antibacterial activity against S. aureus, S. epidermidis, N. gonorrhoeae, E. coli, E. aerogenes, E. cloacae, C. freundii, K. pneumoniae subsp. pneumoniae, P. mirabilis, M. morganii, H. influenzae, A. calcoaceticus, Acinetobacter sp. and C. jejuni and only a few strains were resistant to OFLX. Moreover, OFLX has superior antibacterial activity against many species compared not only to norfloxacin but also to most of the conventional antibacterial drugs. 2. When studied by sampled materials such as sputum, urine, abscesses and otorrhea, OFLX occasionally showed different actions against the same species from different sources. Almost species from the urinary isolates were less sensitive than those from the sputum.     

Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2006

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 876 strains of Gram-positive bacteria, 1764 strains of Gram-negative bacteria, and 198 strains of anaerobic bacteria obtained from 30 medical institutions during 2006 was measured. The results were as follows; 1. MEPM was more active than the other carbapenem antibiotics tested against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MEPM was also active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus. 2. As for Pseudomonas aeruginosa, all of the MEPM-resistant strains were resistant to imipenem (IPM). MEPM showed low cross-resistant rate both againt IPM-resistant P. aeruginosa (41.8%) and ciprofloxacin-resistant P. aeruginosa (33.3%). 3. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 4.3% (6 strains) in Escherichia coli, 1.1% (1 strain) in Citrobacter freundii, 21.7% (5 strains) in Citrobacter koseri, 3.1% (4 strains) in Klebsiella pneumoniae, 3.3% (3 strains) in Enterobacter cloacae, 0.8% (1 strain) in Serratia marcescens, and 4.9% (2 strains) in Providencia spp. The proportion of metallo-beta-lactamase strains was 3.1% (10 strains) in P. aeruginosa. 4. Of all species tested, there were no species, which MIC90 of MEPM was more than 4-fold higher than those in our previous study. Therefore, there is almost no significant decrease in susceptibility of clinical isolates to meropenem. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem at present, 11 years after available for commercial use.     

Antibacterial activity of gentamicin against clinical isolates in pediatrics

Antibacterial activity of gentamicin (GM), along with activities of other aminoglycosides and beta-lactams, was studied against clinical isolates collected from pediatric patients during a period of May 1986-April 1987. 1. GM-resistance was noted in 22% of Staphylococcus aureus, 6% of Proteus vulgaris, 8% of Morganella morganii, 40% of Providencia spp., 6% of Enterobacter spp., 14% of Serratia marcescens, and 14% of Pseudomonas aeruginosa isolates. No GM-resistance was observed with isolates of Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. 2. The antibacterial activity of GM against clinical isolates from pediatric patients was found to be comparable to its activity against clinical isolates from adults studied at the same time. 3. The majority of GM-resistant strains of S. aureus were MCRSA, and the GM-resistant strains of S. marcescens and P. aeruginosa were found also to be resistant to multiple drugs. 4. GM-resistant strains were found at relatively high rates (14-22%) in S. aureus, S. marcescens and P. aeruginosa. These rates did not increase compared to the rates observed in the first half of the 1980's. 5. GM was considered to have poor antibacterial activity against genus Providencia. It is concluded from above results that GM still maintains effective antibacterial activity against many of causative organisms of infections in both adults and children.     

In vitro activities of 23 antimicrobial agents against 4,993 gram-positive and gram-negative bacterial strains isolated from multicenter of Japan during 1994--in vitro susceptibility surveillance.Levofloxacin-Surveillance Group

In a surveillance study conducted during 1994 at 24 medical institutes from different geographical areas of Japan, the susceptibility of clinical isolates to twenty three comparative agents, such as ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin, ampicillin, clavulanic acid/amoxicillin, oxacillin, piperacillin, cefaclor, cefotiam, cefdinir, cefclidin, ceftazidime, cefpirome, imipenem, aztreonam, vancomycin, minocycline, chloramphenicol, clarithromycin, sulfamethoxazole/trimethoprim, amikacin, and gentamicin, were tested by the standard broth micro-dilution method. A total of 4,993 isolates tested in this study included Streptococcus pneumoniae, methicillin susceptible Staphylococcus aureus (MSSA), methicillin resistant Staphylococcus aureus (MRSA), coagllase negative streptococci (CNS), Enterococcus faecalis, Enterococcus faecium, Enterobactericeae, Pseudomonas aeruginosa from patients with urinary tract infections or respiratory tract infections, and Haemophilus influenzae. For MSSA, S. pneumoniae, Enterobacteriaceae, and H. influenzae, more than 70% of the isolates was susceptible to fluoloquinolones. However, resistance occurred in more than 50% of MRSA and P. aeruginosa isolated from UTI. Fluoroquinolones were found to be effective against high level penicillin-resistant S. pneumoniae, the third generation cephem-resistant Enterobacteriaceae and ampicillin-resistant H. influenzae.     

2009年401医院1802株分离株细菌药敏试验分析

目的调查分析2009年401医院临床分离常见病原菌对常用抗菌药物耐药情况。方法采用纸片扩散法进行药敏试验,按CLSI 2009年标准判定药敏结果并用WHONET5.4软件进行数据分析。结果 2009年401医院共分离细菌1 802株,其中革兰阴性杆菌1 373株,占76.19%,革兰阳性菌429株,占23.81%。MRSA和MRCNS检出率分别为69.36%和36.23%,未检测到万古霉素中介和耐药的葡萄球菌和肠球菌。大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌ESBLs的发生率分别为71.43%、56.60%和29.03%,肠杆菌科细菌对碳青霉烯类(亚胺培南、美罗培南)仍高度敏感;铜绿假单胞菌对头孢他啶的耐药率最低,为11.9%;鲍曼不动杆菌对美罗培南、亚胺培南的耐药率较低,分别为30.9%、32.6%;6.93%鲍曼不动杆菌和3.11%铜绿假单胞菌为泛耐药株(只对多黏菌素敏感)。结论 2009年401医院临床分离菌以革兰阴性菌为主,铜绿假单胞菌位居第一。肠杆菌科细菌对碳青霉烯类的敏感性最高,非发酵菌数量呈上升趋势,且耐药状况严重,应引起高度重视。     

Antibacterial activities and PK/PD parameters of aminoglycosides against recent clinical isolates of gram-negative rods

We examined antibacterial activities and PK/PD parameters of six kinds of aminoglycosides against seven bacterial species of clinical isolates in 2001. Aminoglycoseides examined were gentamicin (GM), dibekacin (DKB), tobramycin (TOB), amikacin (AMK), netilmicin (NTL), and isepamicin (ISP), and bacterial isolates used were each 50 strains of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Citrobacter freundii, Proteus spp., Serratia marcescens and Pseudomonas aeruginosa. All aminoglycosides showed good activities with low MICs against 6 species of Enterobacteriacea except S. marcescens. Eight strains (3.2%) among them were resistant to one or more aminoglycosides. Resistance to multiple aminoglycosides were detected in 16 strains (32%) of S. marcescens, among which 13 strains were resistant to AMK but susceptible to ISP. Three (6%) strains of P. aeruginosa were resistant to multiple drugs, one of which was resistant to all six aminoglycosides, and others were moderately susceptible to AMK and ISP, and susceptible to GM, AMK and ISP. Using a ratio of peak serum concentration to MIC90 (Cmax/MIC90) or a ratio of area under the curve to MIC90 (AUC/MIC90) as a pharmacokinetic and pharmacodynamic (PK/PD) parameter, we estimated the efficacy of the drug. An excellent effect of ISP, which was injected intramuscularly or intravenously at a dose of 400 mg, was expected for strains of Enterobacteriacea except S. marcescens. The Cmax/MIC90 ratios for S. marcescens were comparably higher in GM and ISP and that for P. aeruginosa were rather high in TOB when compared to other aminoglycosides. Another PK/PD parameter, AUC/MIC90 ratio, was high enough in NTL and ISP for Enterobacteriacea, suggesting good efficacy of these drugs. The (AUC/MIC90) ratios for S. marcescens were comparably high in GM and ISP, and that for P. aeruginosa were high in TOB, DKB, and ISP.     

Antibacterial activity of gatifloxacin against various fresh clinical isolates in 2002

Antibacterial activities of gatifloxacin (GFLX) and other antibacterial drugs against various fresh clinical strains (800 isolates) isolated from specimens of patients in 2002 were compared. GFLX was more active than levofloxacin and ciprofloxacin against Gram-positive bacteria such as methicillin susceptible Staphylococcus aureus and Streptococcus pneumoniae. For these isolates, clarithromycin and azithromycin were less active (MIC90; > 16- > 64 micrograms/mL), GFLX was more active than cefdinir. For Escherichia coli, Klebsiella pneumoniae, Acinetobacter species, Haemophilus influenzae and Moraxella (Branhamella) catarrhalis, three quinolones including GFLX were potently active (MIC90; < or = 0.06-0.5 microgram/mL). Pseudomonas aeruginosa isolated from urinary tract infections were resistant to three quinolones including GFLX (MIC90; 32-64 micrograms/mL), however P. aeruginosa isolated from respiratory and otolaryngological infections were more susceptible (MIC90; 0.5-2 micrograms/mL). Quinolones were less active against Neisseria gonorrhoeae as compared with the cephem antibiotics tested, but GFLX was the most active against N. gonorrhoeae among the quinolones tested. In this study, we investigated activity of GFLX against fresh clinical strains isolated early in 2002, GFLX is widely and potently active against S. aureus, S. pneumoniae and various Gram-negative bacteria.     

Antibiotic resistance of bacterial strains isolated from children in Child Health Center, Warsaw

This study examines the antibiotic susceptibility of 1792 bacterial strains isolated from hospitalized children between January and December 1993. A total of 1015 Gram-negative rods represented by members of Enterobacteriaceae family (770) and nonfermenters (245) were isolated. The most resistant strains were noticed among Klebsiella pneumoniae and Enterobacter cloacae. From 38% to 46% of K. pneumoniae strains were resistant to third-generation cephalosporins, but all of them were sensitive to imipenem. From 60% to 80% of E. cloacae isolates were resistant to all beta-lactams, but sensitive to imipenem. Resistance of P. aeruginosa to aminoglycosides varied from 30% for gentamicin to 5% for amikacin. About 40% of P. aeruginosa strains were resistant to carbenicillin, and 25% to azlocillin and piperacillin, but only two strains were resistant to ceftazidime and imipenem. Among Gram-positive cocci the most frequently encountered were coagulase-negative staphylococci, followed by Staphylococcus aureus and Enterococcus faecalis. The methicillin-resistant strains of coagulase-negative staphylococci and S. aureus consisted 74.8% and 34%, respectively. All strains of methicillin-resistant coagulase-negative staphylococci and S. aureus were sensitive to vancomycin.     

Susceptibility of Pseudomonas aeruginosa to a photodynamic effect of the arginine hematoporphyrin derivative

The photodynamic effect of the arginine hematoporphyrin derivative (HpD-Arg(2)) on the growth of selected Pseudomonas aeruginosa clinical isolates is described as compared to the effect of hematoporphyrin derivative (HpD). Growth inhibition of HpD-Arg(2) of three Gram-positive strains (Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus) and five laboratory strains of Gram-negative bacteria (Escherichia coli, Proteus vulgaris, P. aeruginosa, Klebsiella pneumoniae and Enterobacter cloacae) was observed as well. Serratia marcescens strain was resistant to light-activated HpD-Arg(2) or HpD. The antimicrobial activity of light-activated HpD-Arg(2) against P. aeruginosa may offer an additional option in the anti-pseudomonal therapy of wounds.     

Antimicrobial activity of sulbactam/cefoperazone. Comparison with other new cephems

Antimicrobial activities of sulbactam/cefoperazone (SBT/CPZ) against 50 fresh clinical isolates of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter spp., Serratia marcescens, Proteus mirabilis, Proteus vulgaris and Pseudomonas aeruginosa were compared to those of CPZ, Cefotiam (CTM), Cefotaxime (CTX) and Latamoxef (LMOX). Minimal inhibitory concentrations (MIC's) of SBT and CPZ mixed in a ratio of 1:1 were determined by the dilution method using Mueller-Hinton agar and expressed by absolute concentrations of CPZ. Antimicrobial activities of SBT/CPZ against principally penicillinase (PCase) producing bacteria, i.e., S. aureus, E. coli, K. pneumoniae, P. mirabilis, were superior to those of CPZ alone. The presence of SBT in concentrations around 0.39 approximately 1.56 micrograms/ml clearly enhanced CPZ's antimicrobial activities against these PCase producing strains. The synergistic antimicrobial effects of SBT in combination with CPZ were less pronounced against principally cephalosporinase (CEPase) producing bacteria, i.e., C. freundii, Enterobacter spp., S. marcescens, P. vulgaris, and P. aeruginosa, and exerted with SBT at concentrations around 3.13 approximately 12.5 micrograms/ml. Comparative antimicrobial activities indicated by MIC80's of tested agents showed that SBT/CPZ had more stable activities against bacteria ranging from Gram-positive to Gram-negative bacteria than CTM, CTX and LMOX. MIC's of SBT/CPZ were higher than 25 micrograms/ml against 8% of S. aureus, 18% of C. freundii, 10% of Enterobacter spp., 26% of S. marcescens, 2% of P. vulgaris, and 18% of P. aeruginosa. These resistant strains against which the addition of SBT showed no synergism, may possess other mechanism of resistance than beta-lactamase production. It is concluded that the presence of CPZ resistant strains is an actual current problem and not an imaginary future problem, and that the number of resistant strains against other new cephems which have different chemical structure from CPZ is increasing. When these present bacteriological environments are considered, the appearance of SBT/CPZ in the clinical practice is timely and meaningful.     

Effect of combination of cefsulodin and mecillinam

The effect of cefsulodin in combination with mecillinam was examined against a wide range of bacterial species. The antibacterial spectrum was widened by the combination of cefsulodin and mecillinam in the ratio of 5:1 and 10:1. In overall observations, in the in vitro test, a synergistic effect against clinical isolates was found on Klebsiella pneumoniae, Citrobacter freundii, Enterobacter cloacae, Serratia marcescens, proteus mirabilis and Proteus vulgaris, and an additive effect was found on Staphylococcus aureus, Escherichia coli, Proteus morganii, Proteus rettgeri, Proteus inconstans and Pseudomonas aeruginosa. In in vivo tests, a synergistic effect was observed on S. marcescens TN 66 and K. pneumoniae DT infections and an additive effect was observed on S. aureus 308 A-1, E. coli O-111 and T-7, C. freundii TN 518, E. cloacae TN 603, P. vulgaris GN 4712, P. morganii Tn 373 and P. aeruginosa U 31 infections.     

In vitro antibacterial activity of various cephems against clinical isolates from complicated urinary tract infections

In vitro antibacterial activity of several cephems (CEZ as the first generation (group A); CTM and CMZ as the second generation (group B); CMX, CPZ, LMOX, CTX and CZX as the third generation (group C)) against 8 species, each of 54 strains, of Gram-negative clinical isolates from complicated urinary tract infection was compared by determination of the MICs. The following results were obtained: The most sensitive drugs against each species in MIC80; CTX (MIC80 0.20 microgram/ml) against E. coli, CMX (1.56 microgram/ml) against K. pneumoniae, LMOX (0.39 microgram/ml) against P. mirabilis, LMOX (0.78 microgram/ml) against Indole (+) Proteus, CMX and CPZ (50 micrograms/ml) against E. cloacae, CMX and LMOX (50 micrograms/ml) against C. freundii, CMX (3.13 micrograms/ml) against S. marcescens and CPZ (25 micrograms/ml) against P. aeruginosa The most sensitive drugs against each species in MICS100; CMX (MIC100 3.13 micrograms/ml) against E. coli, CMX (6.25 micrograms/ml) against K. pneumoniae, CTX (0.78 microgram/ml) against P. mirabilis, LMOX (1.56 microgram/ml) against Indole (+) Proteus, CPZ (100 micrograms/ml) against E. cloacae, CMX (100 micrograms/ml) against C. freundii, CMX (12.5 microgram/ml) against S. marcescens and CPZ (50 micrograms/ml) against P. aeruginosa. In each species, the group C were most sensitive followed by those of the group B. Many isolates were highly resistant to the group A (especially in C. freundii, S. marcescens and P. aeruginosa).     

In vitro susceptibilites to levofloxacin and various antibacterial agents of 11,475 clinical isolates obtained from 52 centers in 2002

The susceptibilities of bacteria to fluoroquinolones (FQs), especially levofloxacin, and other antimicrobial agents were investigated using 11,475 clinical isolates collected in Japan during 2002. Methicillin susceptible staphylococci, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, the family of Enterobactericeae, Haemophilus influenzae and Acinetobacter spp. exhibited stable and high susceptibilities to FQs. The rate of FQs-resistant MRSA was 80 approximately 90%, being markedly higher than that of FQs-resistant MSSA. The FQs-resistance rate of MRCNS was also higher than that of MSCNS, however, it was lower than that of MRSA. No FQs-resistant clinical isolates of Salmonella spp. were detected in any of the surveys. Thirteen of Escherichai coli 696 isolates, 8 of Klebsiella pneumoniae 630 isolates and 33 of Proteus mirabilis 373 isolates produced extended-spectrum beta-lactamase (ESBL), furthermore 6 of 13 in E. coli, 1 of 8 in K. pneumoniae and 14 of 31 ESBL-producing isolates, and in P. mirabilis were FQs resistant. Attention should be focused in the future on the emergence of ESBL in relation to FQs resistance. The rate of FQs-resistant P. aeruginosa isolated from urinary tract infection (UTI) was 40 approximately 60%, while 15 approximately 25% of isolates from respiratory tract infection (RTI) were resistant. IMP-1 type metallo beta-lactamase producing organisms were found in 49 of P. aeruginosa 1,095 isolates, 7 of S. marcescens 586 isolates and 4 of Acinetobacter spp. 474 isolates, respectively. Glycopeptide-resistant enterococci or S. aureus was not found.     

Antibacterial activity of cephem antibiotics against isolates from clinical specimens at the Yokohama City University Hospital

Minimum inhibitory concentrations (MICs) of cephem antibiotics against 405 strains belonging to 17 species of clinical isolates were investigated using the standard method of the Japanese Congress of Chemotherapy. The results obtained are summarized below. Cephem antibiotics showed weak antibacterial activities against Enterococcus sp., B. fragilis and S. marcescens. S. pneumoniae, S. agalactiae, E. coli, K. pneumoniae and P. mirabilis were susceptible to cephem antibiotics. Cephem antibiotics of the 1st and the 2nd generations showed weak antibacterial activity against Citrobacter sp. and E. cloacae, while cephem antibiotics of 3rd generation had a good antibacterial activity against these species. Cephem antibiotics of the 2nd and the 3rd generations showed high antibacterial activity against H. influenzae and indole positive Proteus group. Cefoperazone showed high antibacterial activity against P. aeruginosa. Resistance to latamoxef, ceftizoxime and cefoxitin was observed among Staphylococcus sp., while the MICs of other antibiotics against Staphylococcus sp. were fairly low. Number of strains resistant to the 3rd cephem antibiotics seems to be increasing because the 3rd generation of cephem antibiotics have been used frequently. Further investigation will be required on resistant organism to these antibiotics including beta-lactamase producing strains.     

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.     

Distribution and changes in the susceptibility of bacteria isolated from clinical samples. II

In vitro activity of antimicrobial agents such as ABPC, SBPC, MPC, CEZ, CTM, CMZ, CTX, CMX, CZX, LMOX, CPZ, CFS and GM against major clinical isolates, S. aureus, S. pyogenes, E. coli, K. pneumoniae, P. mirabilis, C. freundii, Enterobacter spp., S. marcescens, P. vulgaris and P. aeruginosa, was examined. In this paper, we will report the susceptibility of S. aureus, S. pyogenes, E. coli, K. pneumoniae and P. mirabilis during a three-year period, 1981 to approximately 1983. CEZ- and GM-resistant S. aureus has markedly increased and occupied 24% and 18%, respectively, in 1983. CMZ and CFS have showed potent activity against CEZ-resistant S. aureus. It seems that the abuse of third generation-cephems and new oral cephalosporins is closely related with the increase of cephems-resistant S. aureus. The penicillin- and cephem-resistant strains of S. pyogenes could not be found in our study. Quite a few strains of E. coli, K. pneumoniae and P. mirabilis are resistant to penicillins, and also there is no appreciable change in susceptibility. Some strains of E. coli, K. pneumoniae and P. mirabilis showed low susceptibility to CPZ, but all strains showed high susceptibility and no change in susceptibility to third generations, and these strains showed no tendency to decrease in susceptibility to GM.