Prevalence of primary Helicobacter pylori resistance to several antimicrobials in a Saudi Teaching Hospital.

OBJECTIVE: To determine the resistance rate of the most commonly used antimicrobial agents amongst Helicobacter pylori isolates. METHODS: The agar disk diffusion method (Kirby Bauer) was utilized to determine the susceptibility of 223 H. pylori strains isolated before treatment. Isolates were tested against metronidazole (5 micrograms), clarithromycin (15 micrograms), amoxycillin (10 micrograms), and tetracycline (30 micrograms). RESULTS: The resistance rate was 80% for metronidazole and 4% for clarithromycin. Tetracycline and amoxycillin showed very low degree of resistance with 1 (0.4%) and 3 (1.3%) of the strains resistant to these antibiotics, respectively. Age, sex and ethnicity had a remarkable effect on the resistance rate. CONCLUSION: The results indicate that metronidazole and clarithromycin should not be used as the only antimicrobial agents in the treatment of H. pylori infection. Susceptibility testing using the disk diffusion method is cost-effective in the screening of antimicrobial resistance against H. pylori.

Antibiotic resistance among Gram-negative non-fermentative bacteria at a teaching hospital in Saudi Arabia.

The incidence and antimicrobial resistance of Gram-negative non-fermentative bacteria isolated over 1 year at King Abdulaziz University Hospital, Jeddah, Saudi Arabia were investigated. A total of 499 of these microorganisms were collected and account for 16% of all Gram-negative bacteria isolated. The most common species were Pseudomonas aeruginosa 291 (56%), Acinetobacter baumannii 170 (34%), and Stenotrophomonas maltophilia 35 (7%). 168 (34%) of these microorganisms were isolated from Intensive Care Unit (ICU), 147 (30%) from General Medicine, and 24 (25%) from Surgery wards. ICU was the main site of isolation of P. aeruginosa and S. maltophilia, while A. baumannii was more frequently isolated from medicine and surgery units. The vast majority of the isolates were resistant to many antibiotics tested. The antimicrobial resistance patterns of P. aeruginosa showed lowest resistance to imipenem (13%), amikacin (17%), and ciprofloxacin (18%). Imipenem was also the most active antimicrobial agent against A. baumannii (15%) resistance. S. maltophilia exhibited multi-drug resistance, and was susceptible only to sulfonamide (6%).

Antimicrobial resistance of Streptococcus pneumoniae at a university hospital in Saudi Arabia.

The resistance pattern of 105 consecutive strains of Streptococcus pneumoniae isolated from patients at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia over a 2-year period (March 1998 to February 2000) was determined with the minimal inhibitory concentration (MIC) method using E-test. Overall 6.7% of the isolates were penicillin resistant (MICs > or = 2 mg/L), and 51% were intermediate (MICs 0.12-1 mg/L). The resistance rates to ampicillin, cefotaxime, ceftriaxone, imipenem, erythromycin and clarithromycin were 8.6%, 8.6%, 4.7%, 3.8%, 13%, and 21% respectively. High-level resistance was noted against cotrimoxazole and chloramphenicol, 76% and 68% respectively. Only 2.8% of S. pneumoniae were resistant to amoxycillin-clavulanate; no resistance to vancomycin was observed. Against penicillin-intermediate pneumococcal strains, vancomycin, ceftriaxone, cefotaxime and amoxycillin-clavulanate were the most active compounds. Against penicillin-resistant pneumococci, vancomycin was the most powerful agent, amoxycillin-clavulanate was half as active, whereas ceftriaxone, cefotaxime and imipenem were 4-fold less active than vancomycin. Fifty-six (53%) of the 105 pneumococcal strains were multi-drug resistant.

Gram-negative bacilli isolated from patients in intensive care unit: prevalence and antibiotic susceptibility.

The surveillance of 100 gram-negative bacilli that were recovered from patients in the intensive care unit (ICU) at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia showed that Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Enterobacter species, in this order, were the most frequently isolated organisms. The most common sites were respiratory tract (34%), wounds (24%), urinary tract (18%), and blood (11%). The resistance patterns towards different antimicrobial agents were determined by the minimal inhibitory concentration (MIC) using the E test. Imipenem, ciprofloxacin and amikacin were the most active agents against the isolates. Of the gram-negative isolates, 31% were resistant to at least two of the four major antibiotic groups (e.g. aminoglycosides, fluoroquinolones, third generation cephalosporins, and carbapenems), and 6% to three of the groups. Twenty-nine percent of the gram-negative bacilli were resistant to ceftazidime. Ceftazidime-resistant bacteria were frequently resistant to monobactams, piperacillin/tazobactam and gentamicin.

Aminoglycoside prescription, therapeutic monitoring and nephrotoxicity at a university hospital in Saudi Arabia.

We studied the use of aminoglycosides at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia, including prescriptions, dosage, serum levels, toxic factors and treatment outcome. Two hundred and fifty-six patients on aminoglycosides were involved in the study period November-December 1994: 24 (9.4%) patients were on amikacin and 232 (90.6%) patients were on gentamicin. The serum concentration was below the therapeutic range in 75% of the patients on amikacin and 50% on gentamicin. Serum concentrations within the therapeutic range (> 20 micrograms/ml; < 35 micrograms/ml for amikacin, and > 6 micrograms/ml and < 10 micrograms/ml for gentamicin) were achieved in 4% and 44% of patients respectively. The dosage was adjusted during therapy for 57% of the patients because of low levels, and for 43% of the patients because of toxic levels. More than 30% of the patients had their serum monitored for the first time 3 days after starting aminoglycoside therapy. Aminoglycosides were discontinued before the end of the course in 157 (62%) patients because 24% of them had developed toxic levels and 24% had not responded to the treatment. Successful outcome was achieved in 170 (66%) of the patients, however, 50% of them had inappropriate serum levels. The risk factors that are significantly associated with aminoglycoside nephrotoxicity were duration of therapy (P = 0.008), renal, liver diseases and ampicillin given concurrently with the aminoglycosides (P = < 0.05).

In-vitro activity of ciprofloxacin and sixteen other antimicrobial agents against blood culture isolates.

The in-vitro antibacterial activities of seventeen antimicrobial agents including ampicillin, amikacin, Augmentin, aztreonam, cefazolin, cefuroxime, cefotaxime, ceftizoxime, ceftriaxone, ciprofloxacin, cloxacillin, erythromycin, gentamicin, penicillin G, piperacillin and vancomycin were compared against 100 Gram-negative and Gram-positive strains isolated from blood culture specimens received at the King Abdulaziz University Hospital (KAUH), in Jeddah, Saudi Arabia. The antibacterial susceptibility was determined by the minimal inhibitory concentration (MIC), using an agar dilution method. Ciprofloxacin exhibited the greatest activity, inhibiting 90% of the tested strains (MIC90) at a concentration ranging from < 0.015-0.5 mg/L. Against cloxacillin resistant or susceptible strains of Staphylococcus aureus and coagulase-negative staphylococci, ciprofloxacin had similar activity with MIC90 of 0.2 mg/L. Salmonella typhi and salmonella species which were resistant to ampicillin and augmentin remained sensitive to ciprofloxacin (MIC90 < 0.015-0.125) mg/L.). Against gentamicin sensitive and resistant Pseudomonas aeruginosa and Pseudomonas species, ciprofloxacin MIC90 was 0.5 and 1 mg/L respectively. Aminoglycosides, third generation cephalosporins, aztreonam and antipseudomonal penicillins, on the other hand, showed high MIC90 well above the obtainable serum concentrations against Enterobacteriaceae and Pseudomonas species.

Postoperative wound infection at a university hospital in Jeddah, Saudi Arabia.

A prospective study was made of 1418 surgical wounds at the 250-bed King Abdulaziz University Hospital in Jeddah, Saudi Arabia. Daily examinations of wounds, cultures of all suspicious wounds and 28 days outpatient clinic follow-up were performed. The overall infection rate was 9%. The infection rate after clean surgery was 9.5%. High rates of infections were noted after colon resection (19%), caesarean section (19%), abdominal hysterectomy (10%) and cholecystectomy (10%). The infection rates after appendectomy, mastectomy and herniorrhaphy were approximately 7%. A lower rate of infection was seen after thyroidectomy (2%). The incidence of infection was significantly related to pre-operative stay in hospital and to duration of operation.

Comparative in-vitro activity of fourteen antibiotics against clinical isolates of enterococci.

The in-vitro antibacterial activities of fourteen antimicrobial agents, including ampicillin, amikacin, Augmentin, ceftazidime, cefotaxime, ceftriaxone, ciprofloxacin, erythromycin, gentamicin, penicillin G, piperacillin, rifampicin, streptomycin and vancomycin, were compared against 195 enterococcal strains isolated from clinical specimens received at the King Abdulaziz University Hospital in Saudi Arabia. The antibacterial susceptibility was determined by the minimal inhibitory concentration (MIC) using an agar dilution method. Ampicillin, Augmentin and vancomycin exhibited the greatest activity, inhibiting 90% of the tested strains (MIC90) at 2 micrograms/ml, followed by penicillin G and piperacillin with MIC90 of 4 micrograms/ml. Erythromycin, third generation cephalosporins, aminoglycosides and rifampicin, on the other hand, had poor activity against enterococci with MIC90s well above the obtainable serum concentrations. The clinical implications of resistance to aminoglycosides and the alternative antimicrobial therapy in serious enterococcal infections are discussed in the text.

Comparative in vitro activity of amoxycillin/clavulanate (augmentin), ceftazidime and ceftriaxone against hospital strains of gram-negative and -positive bacteria.

The in vitro antibacterial activities of amoxycillin/clavulanate (Augmentin), ceftazidime and ceftriaxone were compared against 330 gram-negative and gram-positive strains isolated from clinical specimens received at the King Abdulaziz University Hospital (KAUH) in Saudi Arabia. The antibacterial susceptibility was determinated by Stokes method and by the minimal inhibitory concentration (MIC) using an agar dilution method. Ceftazidime and ceftriaxone were the most active antibiotics, inhibiting 90% of the tested strains by obtainable serum concentrations. Augmentin, on the other hand, had much lower activity against most of the strains tested. Ceftazidime's activity was superior to that of ceftriaxone especially against Klebsiella spp., Enterobacter spp., Citrobacter diversus, indole positive Proteus, Providencia stuartii, Acinetobacter calcoaceticus and Pseudomonas aeruginosa. Ceftriaxone had better activity against Serratia orderefera, Morganella morganii and Staphylococcus aureus. Beta-lactamase stable cephalosporins are therefore a potential replacement for aminoglycosides in the antimicrobial therapy of serious Gram-negative infections and alternative agents in the treatment of some Gram-positive infections.