Antibacterial resistance and molecular typing of methicillin-resistant Staphylococcus aureus in a Kuwaiti general hospital

To investigate antibiotic resistance and genetic relatedness of methicillin-resistant Staphylococcus aureus [MRSA] isolated in a general hospital in Kuwait over a period from 1996 to 1998 and 2001. The isolates were characterized by antibacterial susceptibility testing, coagulase serotyping, coagulase gene polymorphism [coag-RFLP] and pulsed-field gel electrophoresis [PFGE]. The MRSA isolates were highly resistant to gentamicin, kanamycin, ciprofloxacin, tetracycline, fusidic acid and mupirocin. The prevalence of gentamicin, kanamycin, streptomycin, tetracycline and erythromycin resistance remained high [80-96%] throughout the study period, but the prevalence of resistance to ciprofloxacin, fusidic acid and mupirocin steadily increased. The already high mupirocin resistance level increased from 12.5 in 1996, to 85.7% in 2001, and the fusidic acid resistance varied between 70.8 and 85.7%. In contrast, chloramphenicol and trimethoprim resistance declined from 25 and 29% in 1996 to 4.7 and 14.2% in 2001, respectively. The majority [91.5%] of the isolates were coagulase serotype 4. Alu I restriction endonuclease analysis of amplified coagulase gene generated four coag-RFLP patterns: 92% of them were coag-RFLP type 1, while types 2,3 and 4 were 3.5,4.6 and 1.1% respectively. PFGE differentiated them into seven pulsotypes [PFGE types 1-7]. The PFGE type 1 pulsotype constituted 90.2% of the isolates. Isolates with the type A coag-RFLP also had the typel PFGE pulsotypes. The concordant results of PFGE and coag-RFLP demonstrated the presence of a persistent MRSA clone in the hospital during the study period

Antimicrobial activity of a series of 1-alkyl-2-[4-Pyridyl] pyridinium bromides against gram-positive and gram-negative bacteria

To test a series of 1-alkyl-2-[4-pyridyl] pyridini-um bromides with alkyl chains containing between 9 and 16 carbons against Gram-positive [Staphylococcus aureus] and Gram-negative [Escherichia coll, Stenotro-phomonas maltophilia, Acinetobacter baumannii and Pseudomonas aeruginosa] bacteria. Chemical synthesis was based on the reaction of 2,4'-bipyridyl with alkyl bromide. Antimicrobial activity of the bipyridyls was measured by growing bacterial cultures on Mueller-Hinton agar in the presence and absence of inhibitors. The compounds were most active against S. aureus. The most active compounds had alkyl chain lengths of between 11 and 16 carbons. Methicillin-sensitive S. aureus was more susceptible to the inhibitors than methicillin-resistant S. aureus

Antimicrobial susceptibility, phage typing and plasmid profile of salmonella enterica serotype paratyphi A strains isolated in Kuwait

To determine the antimicrobial susceptibility, phage type and plasmid profile pattern of Salmonella enterica serotype paratyphi A strains isolated in Kuwait. Material and From January 1995 to December 1999, 106 strains of S. enterica serotype paratyphi A isolated from an equal number of cases of enteric fever, attending the Infectious Disease and Mubarak Al-Kabeer Hospitals in Kuwait were investigated. The isolates were tested for antimicrobial susceptibility to 8 commonly used antimicrobial agents. Their phage type and plasmid profile patterns were determined using an international set of phages and Qiagen plasmid mini kit, respectively. All of the isolates were susceptible to ciprofloxacin, cefuroxime, ceftazidime, piperacillin and co-trimoxazole. One hundred isolates were susceptible to ampicillin, 99 to chloramphenicol and 98 to tetracycline. None of the isolates was multidrug resistant. Sixty-six% of the isolates were phage type I, 27.4% phage type II and 6.6% were untypable. All phage type I and untypable strains had 3 plasmids of 2.2, 5 and 20 kb, whereas phage type II strains had only 1 plasmid of 20 kb. The findings indicate that while all of the isolates of the S. enterica serotype paratyphi A were susceptible to 4 of the drugs tested, some were resistant to ampicillin, chloramphenicol or tetracycline, thereby indicating the need for continued surveillance and monitoring of antimicrobial susceptibility of these isolates

Comparative susceptibility study of multi-resistant gram-negative bacteria by three methods

A series of 70 multiresistant gram-negative bacteria comprising 21 Klebsiella, 4 Enterobacter, 6 Serratia, 5 Escherichia, 4 Citrobacter, 3 Morganella, 2 proteus, 5 Pseudomonas, and 20 acinetobacter were tested against 13 antimicrobial agents; ampicillin, amoxycillin/clavulanic acid, piperacillin, aztreonam, imepenem, cephalothin, cefuroxime, cefotaxime, ceftriaxone, amikacin, tobramycin and ciprofloxacin, using 3 methods, the Vitek [bioMerieux], the Microscan [Baxter] and the Kirby-Bauer methods. Overall there was excellent correlation [> 95%] and no strain was fully resistant to an antibiotic by one method and fully sensitive by another. Anomalous results for ceftriaxone and piperacillin appeared to be a consequence of misinterpretation of results by the Vitek software, while those for aztreonam and amoxicillin / clavulanic acid were associated with consistent differences between growth in the Microscan tray and Vitek card

Sensitivity patterns of gram-negative pathogens to four modern aminoglycosides

Using a modified Kirby Bauer method, we studied the susceptibility of 349 fully identified urinary tract isolates to netilmicin, tobramycin, gentamicin and amikacin. Gentamicin resistance was the most common: 40 isolates were resistant [R] and 7 intermediate [M], followed by tobramycin [31R, 5M], netilmicin [18R, 4M] and amikacin [6R, 5M]. Similar decreasing resistance frequency was found for all genera tested. The relative gentamicin resistance frequency was highest for Providencia [67%], Serratia [57%] Enterobacter and Citrobacter [33%], Pseudomonas [26%] and Morganella [20%]. It was lower for Klebsiella [5%] and Proteus [11%]. No fully gentamicin resistant E. coli were encountered. The majority of isolates resistant to amikacin [82%] and/or 2 other aminoglycosides originated from inpatients. The relative frequency of these multiresistant isolates was 16% for surgical department, 17% for medical, 7% for paediatrics and 2% for maternity, reflecting the length of hospitalization and aminoglycoside usage in these units. Part of this study was presented at the European Congress of Clinical Microbiology, Nice-1989