Antimicrobial susceptibility pattern of Helicobacter pylori strains isolated from adult dyspeptic patients in Tikur Anbassa University Hospital, Addis Ababa, Ethiopia

Presently, there is no published information on the antimicrobial susceptibility pattern of H. pylori strains in Ethiopia to guide the choice of drug for therapy. Therefore, it is becoming clinically relevant to test the in vitro susceptibility of H. pylori clinical isolates prior to treating patients. Susceptibility testing was performed on 50 clinical H. pylori isolates obtained from adult dyspeptic patients referred to the gastrointestinal (GI) Clinic of Tikur Anbassa University Hospital. Five antibiotics were evaluated, by using the Episolmeter test (E-test). The antibiogram of 50 H. pylori clinical isolates showed that all strains were sensitive to clarithromycin, erythromycin and tetracycline, while 38/50 (76%) and 3/50 (6%) of the strains were resistant to metronidazole and amoxicillin, respectively. Infection by metronidazole or amoxicillin resistant H. pylori is an important factor leading to treatment failure. Testing of all H. pylori clinical isolates to metronidazole and amoxicillin is recommended. If it is not possible to perform susceptibility tests on each clinical isolate, a program to survey the prevalence of resistance should be implemented in a given area or population. When treatment of H. pylori infection is indicated in dyspeptic patients, the potential availability, simplicity of use, safety and low cost of the antimicrobial agents have to be taken into account.     

Antimicrobial sensitivity of hippurate-negative Campylobacter and Helicobacter pullorum strains isolated from patients with diarrhea

C. jejuni as well as some hippurate-negative Campylobacter species and related diarrheagenic organisms, are the leading cause of gastroenteritis in our environment all throughout the year. The aim of the present study was to determine the sensitivity of hippurate-negative Campylobacter and Helicobacter pullorum strains isolated from the stools of patients with diarrhea. We tested 39 Campylobacter coli, two C. lari and five Helicobacter pullorum strains identified by mass spectrometry analysis. The sensitivity to amoxicillin-clavulanic acid, erytrhomycin, azithromycin, gentamicin, ciprofloxacin, levofloxacin, tetracycline, tigecycline and chloramphenicol was tested by E-test. Most hippurate-negative Campylobacter and H. pullorum isolates studied showed high resistance to tetracycline and to the two fluorquinolones tested. On the other side, all strains were sensitive to amoxicillin-clavulanic acid, tigecycline and chloramphenicol, while most of them were sensitive to both macrolides tested and to gentamicin.     

Antimicrobial susceptibility of non-fermenting Gram-negative pathogens isolated from cystic fibrosis patients

Non-fermenting Gram-negative bacteria (NFGNB) are increasingly cultured in respiratory samples from cystic fibrosis (CF) patients. This study determined the antimicrobial susceptibility of clinical CF respiratory isolates from distinct geographical regions. A total of 286 isolates (106 Stenotrophomonas maltophilia, 100 Burkholderia spp., 59 Achromobacter spp., 12 Pandoraea spp., 9 Ralstonia spp.) from the Netherlands, Northern Ireland, Spain, USA and Australia were tested. MIC_50/90 values and susceptibility categorisation were determined. Trimethoprim/sulfamethoxazole (SXT) was the most active compound for all micro-organisms (MIC₅₀, 0.12–4 mg/L; MIC₉₀, 1–16 mg/L). For S. maltophilia, 47% and 62% of isolates were susceptible to SXT according to CLSI and EUCAST breakpoints, respectively. Ceftazidime presented lower susceptibility (35%; MIC₅₀, 32 mg/L; MIC₉₀, 256 mg/L). MIC₉₀ values for tobramycin and colistin were >128 mg/L and >16 mg/L, respectively. Regarding Burkholderia, 72%, 56% and 44% were susceptible to SXT, ceftazidime and meropenem, respectively. For both ceftazidime and meropenem, MIC₅₀ and MIC₉₀ values were within the intermediate or resistant category. The most active antibiotics for Achromobacter spp. were SXT (MIC₅₀, 0.5 mg/L; MIC₉₀, 8 mg/L) and imipenem (MIC₅₀, 2 mg/L; MIC₉₀, 8 mg/L). SXT, imipenem and ciprofloxacin were active against 12 Pandoraea spp. (MIC₅₀, 0.12–4 mg/L; MIC₉₀, 1–8 mg/L). Ciprofloxacin (MIC₅₀, 4 mg/L) and SXT (MIC₅₀, 1 mg/L) were the only active antibiotics for Ralstonia spp. There were no statistically significant differences in susceptibility rates between countries. NFGNB other than Pseudomonas aeruginosa are potential pathogens in CF. SXT was demonstrated to be the most active compound against these isolates.     

2009～2011年ICU患者细菌分布及其敏感性调查

目的监测笔者所在医院ICU患者病原菌流行病学分布及敏感性状况。方法收集ICU科室2009年1月~2011年12月送检病原学标本中分离的病原菌及药敏鉴定结果,统计病原菌分布和抗菌药物敏感率。结果分离到病原菌822株,其中革兰阳性球菌197株,占24%;革兰阴性杆菌625株,占76%。排名前6位的病原菌分别为:鲍曼不动杆菌(23.1%),金黄色葡萄球菌(16.9%),肺炎克雷伯菌(14%),铜绿假单胞菌(12.5%),嗜麦芽窄食单胞菌(8.9%),大肠埃希菌属(7.8%)。耐甲氧西林金黄色葡萄球菌检出率为28.9%,尚未发现耐万古霉素的菌株。肠杆菌科细菌对碳青霉烯类高度敏感。鲍曼不动杆菌耐药严重,对亚胺培南的敏感性从91.7%下降到14.8%,对美罗培南则由100%降至13.6%,铜绿假单胞菌的敏感性则保持相对稳定。肠杆菌属对碳青霉烯类保持高度敏感,而大肠埃希菌对三代头孢敏感性下降明显。肺炎克雷伯菌敏感性相对稳定。结论笔者所在医院ICU患者细菌以革兰阴性杆菌多见,革兰阳性球菌则以金黄色葡萄球菌为主,鲍曼不动杆菌呈逐渐增加的耐药趋势,其它药物则保持相对稳定的敏感性。     

Antimicrobial susceptibility of corynebacteria isolated from ewe''s mastitis

The antimicrobial susceptibility of 50 coryneform isolates from subclinical mastitis in sheep was evaluated. Arcanobacterium pyogenes (five isolates) had a susceptibility pattern distinct from the Corynebacterium species tested. The Corynebacterium isolates could be divided in two groups according to the MIC values for ciprofloxacin. Their antimicrobial susceptibility was usually unpredictable and consequently antimicrobial susceptibility tests are necessary for clinical and epidemiological purposes.     

Antimicrobial susceptibilities of Pasteurella strains isolated from humans

The in vitro susceptibilities of 192 consecutive clinical strains of Pasteurella spp. isolated between 1996 and 2003 from soft tissue pus (n = 146), respiratory tract specimens (n = 38) and blood (n = 8) were studied by an agar dilution method. All isolates were susceptible to minocycline, cefotaxime, ofloxacin, ciprofloxacin and levofloxacin. Most strains were susceptible to moxifloxacin, amoxicillin, azithromycin and clarithromycin, whereas lower susceptibility rates to telithromycin (89.4%) were observed among respiratory tract isolates.     

Antimicrobial susceptibility profiles of Pseudomonas aeruginosa and Staphylococcus aureus isolated in Italy from patients with hospital-acquired infections

Here we report the results of the Sentinel Project 2000 and give the susceptibility to selected antibiotics of 108 Pseudomonas aeruginosa and 108 Staphylococcus aureus strains isolated from patients with hospital-acquired lower respiratory tract infections. In P. aeruginosa, susceptibility to aztreonam and ciprofloxacin was lower than 50%. The resistance rate to beta-lactams was up to 25% and to amikacin 15.7%. Blood isolates showed 80-90% susceptibility to all antibiotics tested except for aztreonam and tobramycin. Overall, oxacillin resistance in S. aureus was 45%, reaching 64.3% among the bronchoalveolar lavage isolates, and 42.9% among the blood isolates. These worrying results confirm the need for continuous monitoring of bacterial resistance trends in the hospitals, mainly in ICUs.     

Antibiotic susceptibility of bacterial strains isolated from patients with community-acquired urinary tract infections.

Isolates from urine samples obtained during 1999 were identified and their susceptibility to antimicrobial agents studied along with any production of extended-spectrum beta-lactamases (ESBL) by Escherichia coli and Klebsiella pneumoniae. A total of 13774 samples were analysed using an automatic system for the detection of bacterial ATP (Coral, USA). Of these samples, 49% were reported to be positive and uncontaminated; bacteria most frequently isolated were E. coli (47%), Proteus mirabilis (7%), Enterococcus faecalis (6%) and K. pneumoniae (5%). The susceptibility studies showed 37% E. coli strains resistant to amoxycillin+clavulanate 33% to cotrimoxazole and 22% to ciprofloxacin. Seven strains of E. coli produced ESBL. Thirteen per cent of strains were resistant to cefuroxime but only (1%) to fosfomycin. Resistance to nitrofurantoin in K. pneumoniae was 38%. P. mirabilis showed 52% resistance to cotrimoxazole and 13% Staphylococcus aureus, were methicillin-resistant. E. faecalis did not show any special resistance to normal medication. Fosfomycin continued to show high activity against Gram-negative bacilli. However, enterococci, some species of staphylococci and yeasts were difficult to treat empirically. ESBL were detected in the isolates of E. coli and there were some methicillin-resistant strains of S. aureus.     

Antimicrobial susceptibility of Listeria monocytogenes isolated from meningoencephalitis in sheep

The antimicrobial susceptibility to different antimicrobial agents of 41 Listeria monocytogenes strains isolated from sheep with meningoencephalitis and from feedstuff was tested by both microdilution and disk diffusion methods. Both sets of isolates of L. monocytogenes were susceptible to penicillin G, amoxicillin, cephalothin, erythromycin, vancomycin, rifampicin, gentamicin, kanamycin, trimethoprim, sulfisoxazole, chloramphenicol and ciprofloxacin, but resistant to tetracycline and doxycycline (7.3 and 4.9%, respectively). Tetracycline was the most frequent resistance trait in L. monocytogenes strains of animal origin. Four strains (9.8%) also exhibited reduced susceptibility (MIC 4 mg/l) to doxycycline suggesting the need of surveillance studies to monitor the antimicrobial resistance of Listeria strains of animal origin.     

新生儿感染耐甲氧西林葡萄球菌的药敏分析

目的:探索致新生儿感染的耐甲氧西林葡萄球菌(MRS)流行病学及常见10种抗菌药物敏感性。方法:按《全国临床检验操作规程》鉴定细菌,玻片法血浆凝固酶试验,K－B扩散法药敏试验。结果:分离出葡萄球菌323株,其中金黄色葡萄球菌(SA)55株,耐甲氧西林金葡菌(MRSA)14株(25．5%),表皮葡萄球菌 171株,耐甲氧西林表葡菌(MRSE)102株(59,6%),腐生葡萄球菌97株,耐甲氧西林腐生葡菌(MRSS)52株(53．6%),院内感染株中 MRS所占比例明显高于甲氧西林敏感葡萄球菌(MS),x~2=3.978,P＝0.046。对氨苄西林、青霉素及红霉素总耐药率分别为86.8%、84.6%及68.9%,而对万古霉素及头孢唑啉总耐药率分别仅为6.7%(7/140)及11.3%(26/231),万古霉素对全部SA、甲氧西林敏感表葡菌(MSSE)、甲氧西林敏感腐生葡菌(MSSS)均敏感,MRS对青霉素、氨苄西林、头孢哇啉、头孢呋辛、头孢他啶、庆大霉素、阿米卡星、诺氟沙星及万古霉素的耐药率较MSS明显增高(P＜0.01)。结论:新生儿耐甲氧西林葡萄球菌易引起医院感染,其耐药性明显,值得高度重视．     

Antimicrobial susceptibility of potentially pathogenic halophilic vibrios isolated from seafood

Susceptibility patterns to 27 antimicrobial agents and beta-lactamase production were investigated in potentially pathogenic halophilic vibrios from seafood. The effect of salinity on the response to the drugs in vitro was also studied. All isolates were uniformly sensitive to choramphenicol, imipenem, meropenem but resistant to lincomycin. All were highly sensitive to oxolinic acid, trimethoprim-sulphamethoxazole, doxycycline, flumequine, cefotaxime, nalidixic acid and ciprofloxacin. Some strains of V. harveyi, V. alginolyticus and V. parahaemolyticus apparently had mechanisms of resistance to several beta-lactam antibiotics other than by the production of beta-lactamases. Sixty-nine strains produced penicillinase but a low correlation between beta-lactamase activity and resistance to beta-lactam antibiotics was noted. The salt concentration affected the in vitro susceptibility of halophilic vibrios and the effect of salinity depended on both the individual strains and the antimicrobial tested.     

Antimicrobial susceptibility of Neisseria meningitidis isolated from 1975-1979

During the period 1975 to 1979, 88 isolates of Neisseria meningitidis from cerebrospinal fluid (CSF), 28 isolates from blood, and 89 isolates from other sources were serogrouped and tested for their susceptibility to sulphadiazine, penicillin, minocycline and rifampin. Prior to 1979, isolates from CSF or blood were predominantly serogroup B. In the sample tested, the prevalence of this serogroup decreased while the prevalence of serogroup A isolates increased, until in 1979 this was the predominant serogroup. From 1975, the incidence of sulphonamide-resistance in the serogroup B isolates from CSF or blood decreased. However, all serogroup A isolates from these sources, except the first one tested, were sulphonamide-resistant. The 89 isolates from other sources remained predominantly sulphonamide-sensitive serogroup B. All isolates were sensitive to penicillin, minocycline and rifampin.     

Antimicrobial susceptibility and serotypes of Streptococcus pneumoniae isolated from the patients with respiratory tract infections in Hokusetsu Area of Osaka

One hundred and thirteen strains of Streptococcus pneumoniae (S. pneumoniae) were isolated from the clinical specimens of patients with respiratory tract infections between January and December 1998 in three hospitals in Hokusetsu area of Osaka. We investigated susceptibility of 113 strains of S. pneumoniae to benzylpenicillin (PCG) and other antimicrobial agents and their serotypes. 1) Of the 113 strains of S. pneumoniae isolated, 25.7% were susceptible (PSSP), 51.3% were intermediate (PISP) and 23% were resistant to benzylpenicillin (PRSP). 2) The MICs of cefaclor, cefditoren, cefpodoxime, cefdinir, erythromycin, clindamycin and minocycline were elevated, but the MIC values of cefditoren ranged from < or = 0.03 to 1.0 microgram/ml. The susceptibility of 113 strains to cefditoren was comparatively high. 3) The MIC values of imipenem, meropenem and vancomycin for 81 strains of PISP and PRSP ranged from < or = 0.015 to 1.0 microgram/ml, from < or = 0.015 to 2.0 micrograms/ml and from 0.13 to 0.5 microgram/ml, respectively. The susceptibility of these strains to three antimicrobial agents was superior to that to the other antimicrobial agents examined. 4) Of the 60 strains examined, 19, 6, and 23 serotypes were 30, 25 and 18.3%, respectively. The three serotypes were observed in PISP and PRSP with a high frequency. 5) Isolates of S. pneumoniae were 37.2% for children under 2 years of age and 30.9% for children from 2 to 6 years of age. Most of the strains isolated from these children were resistant.     

Antimicrobial activity of cefetamet against clinically isolated microbial strains collected from urban RTI patients]

The authors studied antimicrobial activities of cefetamet (CFMT) and other leading oral antimicrobials of beta-lactam class against clinically isolated strains from urban respiratory tract infection (RTI) patients from January to March, 1992. 1. CFMT showed potent antimicrobial activities against "3 primary pathogens" of RTIs i.e., Streptococcus pyogenes, Streptococcus pneumoniae, and Haemophilus influenzae, but the drug had a slightly higher MIC than those of a few oxime-type cephems already on the market. 2. CFMT was as stable as cefixime to beta-lactamase, generated by Moraxella subgenus Branhamella catarrhalis, which reduces the antimicrobial activity of cephems. 3. Blood concentrations of CFMT after administering cefetamet pivoxil (CFMT-PI), an oral form of the drug, exceeded the MIC80 against the "3 primary pathogens" as well as M. (B) catarrhalis and Klebsiella pneumoniae, for a duration of approximately 9 and 11 hours, respectively, after single doses of 250 and 500 mg. This suggests that CFMT could remain above the MICs for a sufficient time period with twice daily dosages of normal dose levels. 4. It is concluded that CFMT-PI will be useful for treating urban RTIs.     

Antimicrobial susceptibility of Streptococcus species isolated from clinical mastitis in dairy cows

The antimicrobial susceptibility was determined for 50 Streptococcus uberis, 42 S. dysgalactiae subsp. dysgalactiae and eight S. agalactiae strains isolated from cow mastitis. Only 27% of the strains were susceptible to all antimicrobial compounds tested. Resistance to tetracycline was most frequent (particularly for S. dysgalactiae strains), then macrolide and/or lincomycin resistance. High level resistance to streptomycin and kanamycin was detected. All S. dysgalactiae and S. agalactiae strains were susceptible to beta-lactams but 44% of the S. uberis strains showed an elevated penicillin G MIC. All strains were susceptible to chloramphenicol and rifampicin.     

细菌性尿路感染213株细菌分析及其药物敏感趋势监测

目的:了解临床细菌性尿道感染患者细菌感染的流行趋势和对其药物敏感趋势进行监测,为临床合理用药提供依据。方法通过对东方医院2002年3月至2003年3月临床细菌性尿道感染患者的标本中分离出213株病原菌,进行调查分析和对其药物敏感趋势进行临测。结果:临床患者的标本中共分离出213株细菌。主要致病菌依次为大肠埃希菌104株(48.83％)、屎肠球菌20株(9.39％)、粪肠球菌17株(7.98％)、肺炎克雷伯氏菌12株(5.63％),表皮葡萄球菌11株(5.16％)。其他分离较少的细菌有铜绿假单胞菌9株、金黄色葡萄球菌5株、产酸克雷伯氏菌5株。ESBL确证试验结果:2001年3月至2002年3月共对81株大肠埃希菌22株,产酶率27％;10株肺炎克雷伯菌5株,产酶率50％。结论:临床细菌耐药严重,应根据细菌检验结果合理用药。     

Antimicrobial susceptibility of Gram-negative organisms isolated from patients hospitalised with pneumonia in US and European hospitals: Results from the SENTRY Antimicrobial Surveillance Program, 2009–2012

Here we evaluated the frequency of occurrence and antimicrobial susceptibility patterns of Gram-negative bacteria isolated from patients hospitalised with pneumonia in medical centres in the USA (n = 28) and Europe and the Mediterranean region (EMR) (n = 25) in 2009–2012. Susceptibility testing was performed by reference broth microdilution methods. Overall, 12 851 isolates were collected (6873/5978 in USA/EMR). The same top 11 organisms were observed in both geographic regions, but in different rank orders, and Gram-negative organisms represented 61.5/76.1% of strains in USA/EMR. Pseudomonas aeruginosa was the most frequently isolated Gram-negative organism in both regions (20.9/20.9% of cases in USA/EMR) and showed reduced susceptibility to most antimicrobials tested, including ceftazidime (79.6/68.7% susceptibility in USA/EMR), meropenem (76.3/65.8%) and piperacillin/tazobactam (72.9/63.9%). Klebsiella spp. was isolated from 9.7/11.6% of cases and showed extended-spectrum β-lactamase (ESBL) phenotype rates of 19.5/35.1% in USA/EMR. Meropenem and amikacin were active against 62.3/78.7% and 60.8/85.2% of ESBL phenotype Klebsiella spp. from USA/EMR, respectively. Enterobacter spp. ranked fourth in the USA (5.9%) and sixth in EMR (5.5%), whereas Escherichia coli ranked fifth in the USA (5.5%) and third in EMR (11.8%). Acinetobacter spp. and Stenotrophomonas maltophilia combined were isolated from 8.0/10.7% of cases in USA/EMR. A significant increase in P. aeruginosa susceptibility to meropenem and a significant decrease in gentamicin susceptibility among Klebsiella spp. were noted in EMR. These results confirm that very few agents remain broadly active against the most frequently isolated Gram-negative organisms from patients with pneumonia in US and EMR medical centres.     

Antimicrobial susceptibility of Pseudomonas aeruginosa isolated in Fukushima Prefecture

We investigated the susceptibility of Pseudomonas aeruginosa (isolated from the sputum of patients with respiratory infection in 4 medical institutions in Fukushima Prefecture) to 8 beta-lactam antibiotics including three carbapenems and relationships among MICs of antibiotics tested. The MIC90 values for a total of 216 strains were 6.25 micrograms/ml for meropenem, 12.5 micrograms/ml for imipenem and ceftazidime, 25 micrograms/ml for panipenem and cefsulodin, 50 micrograms/ml for cefpirome and over than 200 micrograms/ml for cefoperazone and piperacillin. The frequency of resistance of these strains to each antibiotic was as follows: The resistant strains were 19 (8.8%) for meropenem, 34 (15.7%) for imipenem and ceftazidime, 50 (23.1%) for cefsulodin, 72 (33.3%) for panipenem, 76 (35.2%) for piperacillin and 90 (41.7%) for cefpirome. Eighteen strains (18.3%) of 19 meropenem resitant straisn were resistant to imipenem and panipenem, but 16 strains of the 34 imipenem-resistant strains and 54 strains of the 72 panipenem-resistant strains were susceptible to meropenem. In investigation of isolation of multi-resistant Pseudomonas aeruginosa, the susceptibility of strains tested to 7 antibiotics except cefoperazone was as follows: The strains susceptible to all the 7 antibiotics were 92 strains (42.6%), and 33 strains (15.2%) were resistant to 2 antibiotics, 31 strains (14.4%) were resistant to 1 antibiotic, 21 strains (9.7%) were resistant to 3 antibiotics, 13 strains (6.0%) were resistant to 5 antibiotics, 9 (4.2%) were resistant to 4 and 7 antibiotics, and 8 strains (3.7%) were reistant to 6 antibiotics. Since the emergence of these multi-resistant strains is closely related to frequent use of antibiotics for nosocomial infections, special attention should be paid to the antimicrobial susceptibility of Pseudomonas aeruginosa and the situation of antibiotic resistant strains.