Comparative in vitro activity of tigecycline and other antimicrobial agents against Shigella species from Kuwait and the United Arab of Emirates.

Shigella species isolated from stool samples of symptomatic patients of all age groups at the Mubarak Al Kabir Hospital and Infectious Diseases Hospital, Kuwait and Tawam Hospital, UAE during a 2-year period were investigated for their susceptibility to tigecycline and several other antibiotics by determining the minimum inhibitory concentrations (MICs) using the E test method. A total of 100 and 42 strains were collected from UAE and Kuwait, respectively. The extent of drug resistance in the Shigella spp. isolates from these two countries was analyzed by criteria recommended by the Clinical and Laboratory Standards Institute (CLSI). Amikacin, cefotaxime, cefuroxime, ciprofloxacin, imipenem, meropenem, piperacillin-tazobactam and tigecycline had excellent activities against all isolates from UAE and Kuwait with MIC(90s) of 12, 0.094, 4, 0.012, 0.25, 0.032, 3 and 0.25 microg/ml and 4, 1, 4, 0.125, 0.38, 0.19, 3 and 0.25 microg/ml, respectively. Half of all isolates from both countries were resistant to ampicillin. None of the isolates in Kuwait was resistant to amoxicillin-clavulanic acid compared with 22% in UAE. Resistance to chloramphenicol was recorded in 50 and 36% of the isolates in Kuwait and UAE, respectively. The percentages of non-susceptibility to trimethoprim-sulfamethoxazole and tetracycline were very high in Kuwait and UAE (76% vs. 92% and 76% vs. 98%, respectively). Notably, one isolate, S. flexneri, from UAE had reduced susceptibility to ciprofloxacin (MIC, 0.25 microg/ml). Four (2.8%) of the isolates were ESBL producers by the E test ESBL method but could not be confirmed by PCR using primers for bla(CTX-M), bla(SHV) and bla(TEM). In conclusion, Shigella spp. isolated from symptomatic patients in Kuwait and the UAE demonstrated high rates of resistance to the first-line antibiotics but very susceptible to the carbapenems, cephalosporins, fluoroquinolones and tigecycline. Tigecycline holds promise as a potential drug of choice for the therapy of severe shigellosis.

Surveillance of antibacterial resistance in Staphylococcus aureus isolated in Kuwaiti hospitals.

OBJECTIVE: To investigate the prevalence of antibiotic resistance among Staphylococcus aureus isolated in Kuwaiti hospitals. MATERIALS AND METHODS: S. aureus were isolated and identified following standard microbiological methods. Antibacterial susceptibility test was performed by disk diffusion and the measurement of minimum inhibitory concentration with E-test strips. RESULTS: A total of 1,846 S. aureus isolates were analyzed from 13 hospitals between 1 March and 30 October 2005. They were isolated from 1,765 (95.6%) inpatients and 81 (4.4%) outpatients. Methicillin resistance was detected in 588 (32.0%) of the isolates. The methicillin-resistant S. aureus (MRSA) consisted of 461 (78%) multiresistant and 127 (22%) nonmultiresistant isolates. The nonmultiresistant MRSA consisted of epidemic MRSA-15 and community-associated MRSA. The community-associated MRSA was detected in all hospitals with MRSA, indicating its establishment in Kuwaiti hospitals. The proportion of isolates resistant to gentamicin, kanamycin, erythromycin, tetracycline, ciprofloxacin, fusidic acid and trimethoprim was higher among MRSA than methicillin-susceptible S. aureus (MSSA) isolates. Twenty-four and 22% of MRSA and MSSA isolates, respectively, expressed reduced susceptibility to vancomycin (minimum inhibitory concentration = 3-4 mg/l). CONCLUSION: The study revealed the presence of methicillin resistance in 32% of S. aureus isolated in Kuwaiti hospitals and revealed an increase in the number of MRSA and MSSA with reduced susceptibility to vancomycin.

Plasmid-mediated high-level ceftriaxone resistance in a Salmonella enterica serotype typhimurium isolate.

OBJECTIVE: To present the first documented case of acute infectious gastroenteritis caused by high-level ceftriaxone-resistant Salmonella enterica serotype typhimurium in Kuwait. SUBJECT AND METHODS: Isolation from stool specimen and species identification of current enteric pathogen was carried out according to standard methods. Susceptibility to antibiotics was determined by the disc diffusion method on Mueller-Hinton agar. Minimal inhibitory concentrations (MICs) were measured with E-test strips. The production of extended spectrum beta-lactamase (ESBL) was studied by the double disc synergy method and E-test ESBL strips. Plasmid DNA isolation was performed by the rapid alkaline lysis method. Plasmid DNA was transferred by conjugation to a recipient strain of Escherichia coli. RESULTS: The isolate of S. enterica serotype typhimurium was resistant to ceftriaxone (MIC >256 mg/l), cefotaxime and ceftazidime, and produced ESBL. Ceftriaxone and cefotaxime resistance were co-transferred on a 3.2-kb plasmid to the E. coli recipient strain. Loss of the 3.2-kb plasmid from the transconjugant resulted in the co-loss of ceftriaxone and cefotaxime resistance confirming the carriage of ceftriazone resistance on the 3.2-kb plasmid. CONCLUSION: Plasmid-mediated high-level resistance to ceftriaxone and ESBL production in Salmonella serotype typhimurium is an emerging problem among Salmonella that requires closer monitoring of antimicrobial resistance among these bacterial species.

Incidence of bloodstream infections in a speciality hospital in Kuwait: 8-year experience.

OBJECTIVES: To determine the frequency of isolation and antibiotic-susceptibility patterns of clinically significant bacterial pathogens isolated from blood. MATERIALS AND METHODS: The study was conducted over a period of 8 years (1995-2002) at Infectious Diseases Hospital (IDH), Kuwait. Demographic and clinical data were obtained from medical records. 18,535 blood cultures were analyzed. Disk diffusion method was used to perform antibiotic-susceptibility testing. Minimum inhibitory concentrations of 9 antimicrobials were determined using E-test. Double disk (potentiation) test and E-test ESBL strips were used to detect the production of extended-spectrum beta-lactamases (ESBLs). RESULTS: Salmonella spp. and Brucella spp. were predominant blood isolates, and represented 60.6 and 30.0% of all clinically significant episodes of bloodstream infections, respectively. Among the Salmonella, Salmonella enterica serotypes typhi and paratyphi A were most frequently isolated. The percentage of multidrug resistance (MDR) among them varied from 22 to 51%. A high percentage (40%) of MDR S. enterica serotypes typhi and paratyphi A also showed reduced susceptibility to ceftriaxone and ciprofloxacin. CONCLUSION: During the study period, Salmonella spp. and Brucella spp. were predominant blood isolates. MDR S. enterica serotypes typhi and paratyphi A, with reduced susceptibility to ceftriaxone and ciprofloxacin, are among the most frequent causes of bloodstream infections in IDH, suggesting the need to monitor their susceptibility.

Etiology and antibiotic susceptibility patterns of community-acquired urinary tract infections in a Kuwait hospital.

OBJECTIVE: The aim of this study was to determine the distribution and antibiotic susceptibility patterns of bacterial strains isolated from patients with community-acquired urinary tract infections (UTIs) at the Infectious Diseases Hospital, Kuwait. MATERIALS AND METHODS: The study was conducted over a 7-year period. Patient information was obtained from medical record files. Antibiotic-sensitivity testing was performed by disk diffusion. E test and double disk diffusion methods were used to study the production of extended spectrum beta-lactamases. RESULTS: Of the 14,042 urine samples processed, significant bacteriuria (>10(5) cfu/ml) was detected in 1,606 (11.4%). The majority (74.5%) of the isolates were from women while the remaining 25.5% were from men. The majority of infections (75%) were due to Enterobacteriaceae, coagulase-negative staphylococci (10.3%) and group B streptococci (8.7%). Among the gram-negative enteric bacilli high prevalence of resistance to ampicillin, amoxicillin/clavulanic acid, cephalothin, and trimethoprim/sulfamethoxazole was observed. Increasing resistance to ciprofloxacin and gentamicin was observed in E. coli isolates over the 7 years. Multiple resistance was detected in 53.8 and 41% of E. coli and Klebsiella spp. strains, respectively. No glycopeptide-resistant enterococci were isolated. CONCLUSION: This study revealed that Enterobacteriaceae were the predominant bacterial pathogen of community-acquired UTIs in Infectious Diseases Hospital, Kuwait. It also demonstrated an increasing resistance to ciprofloxacin, gentamicin and the production of extended spectrum beta-lactamase among UTI pathogens in the community.