Investigation of plasmid-mediated quinolone resistance among isolates obtained in a Turkish intensive care unit

The aim of this study was to search for three plasmid-encoded, quinolone-resistance determinants: qnrA, qnrB, and qnrS. Thus, 460 Gram-negative strains belonging to 11 different genera (clinical, 347; non-clinical, i.e., from a rectal swab, 113), of which 40% were ciprofloxacin-resistant, were recovered from patients in an intensive care unit at the Istanbul Medical Faculty, Turkey, in the years 2000 and 2006. PCR with primers specific for qnrA, qnrB, and qnrS genes and primers specific for a series of ESBL genes were used. One qnrB1 and two qnrS1 genes were identified in three ESBL-positive isolates, whereas no qnrA-positive strain was found. The qnrB1 determinant was identified in a ciprofloxacin-susceptible Enterobacter cloacae isolate that expressed CTX-M-15 beta-lactamase. Two qnrS1-determinants were found in two ciprofloxacin-susceptible E. cloacae isolates that were clonally related, but that had been isolated from different patients; both of these isolates expressed the same ESBL, CTX-M-3. This study detected the first plasmid-mediated quinolone-resistance determinants qnrB1 and qnrS1, among clinical strains obtained from patients in Turkey

TEM-1 AND ROB-1 PRESENCE AND ANTIMICROBIAL RESISTANCE IN HAEMOPHILLIS INFLUENZAE STRAINS, ISTANBUL, TURKEY

Resistance of 235 Haemophilus influenzae clinical isolates from Istanbul Medical Faculty Hospital, Turkey were determined against 19 antibiotics by disc diffusion method, and minimum inhibitory concentrations (MICs) of those found resistant to ampicillin, cefuroxim, chloramphenicol and meropenem were measured using E-test. Ampicillin-resistant isolates producing beta-lactamase as demonstrated by a nitrocefin assay were analyzed for the presence of TEM-1 and ROB-1 genes by PCR. Eleven percent of the isolates were resistant to ampicillin (10 mu g/ml), of which 73% were beta-lactamase positive and carried TEM-1 gene, but none were positive for ROB-1 gene. All isolates susceptible to amoxicillin-clavulanate (20/10 mu g/ml), azithromycin (15 mu g/ml), aztreonam (30 mu g/ml), cefotaxime (30 mu g/ml), ceftriaxone (30 mu g/ml), ciprofloxacin (5 mu g/ml) levofloxacin (5 mu g/ml), and telithromycin (15 mu g/ml) but 24%, 15%, 4%, 4%, 2%, 1%, 1%, 0.5%, 0.5% and 0.5% were resistant to trimethoprim-sulfamethoxazole (1.25/23.75 mu g/ml), tetracycline (30 mu g/ml), cefaclor (30 mu g/ml), clarithromycin (15 mu g/ml), cefuroxime (30 mu g/ml), meropenem (10 mu g/ml), chloramphenicol (30 mu g/ml), ampicillin-sulbactam (10/10 mu g/ml), nalidixic acid (30 mu g/ml), and fosfomycin (30 mu g/ml), respectively. MIC values of three cefuroxime-resistant isolates was 24, 48 and > 256 mu g/ml, respectively; of two meropenem-resistant strains > 256 mu g/ml; and of two chloramphenicol-susceptible isolates (by disc diffusion method) 6 mu g/ml (considered as intermediate susceptible). Multiple-antibiotics resistance was detected in 15% of the strains, with resistance to 2, 3, 4, 5 and 6 antibiotics in 8.5%, 4%, 2%, 0.5% and 0.5% of the isolates, respectively. By identifying beta-lactamase-negative ampicillin-resistant H. influenzae, empirical therapy with beta-lactam/beta-lactamase inhibitor combinations and second generation cephalosporins would be inappropriate for such patients (approximately 3%). Our findings will contribute to the epidemiological and clinical data regarding H. influenzae infection in Turkey

Genotype and antibiotic susceptibility patterns of Pseudomonas aeruginosa and Stenotrophomonas maltophilia isolated from cystic fibrosis patients

The purpose of this study was to type the Pseudomonas aeruginosa and Stenotrophomonas maltophilia isolates recovered from cystic fibrosis (CF) patients by random amplified polymorphic DNA (RAPD)PCR and to determine the antibiotic susceptibility of these strains. P. aeruginosa (n = 49), and S. maltophilia (n = 11) isolates which had been recovered from 16 and 8 patients, respectively, during a 1-year period were investigated. Three primers were used for RAPD-PCR typing. Antibiotic susceptibility testing of all isolates was performed by the disc diffusion method. RAPD-PCR analysis revealed 21 (P. aeruginosa) and 9 (S. maltophilia) different genotypes. According to the antimicrobial susceptibility results, the P. aeruginosa and S. maltaphilia strains were cumulated into 24 and 11 groups, respectively. The CF patients were colonized or infected with P. aeruginosa strains of single or sometimes multiple genotypes which remained stable over several months. Our results also revealed that cross-colonization might be possible among the patients who are followed up at the same center. Piperacillin-tazobactarn for P. aeruginosa and trimethoprim-sulfamethoxazole for S. maltophilia were found to be the most active antibiotics according to our results

High prevalence of CTX-M-type beta-lactamase in Escherichia coli isolates producing extended-spectrum beta-lactamase (ESBL) and displaying antibiotic co-resistance

In the present study, we investigated the prevalence of CTX-M-type beta-lactamase in extended spectrum beta-lactamase (ESBL)-producing Escherichia coli isolated in our hospital as well as their antibiotic resistance and co-resistance rates. Two hundred nineteen E. coli isolated from clinical specimens between 2006 and 2007 were included. Antibiotic susceptibility test was performed using disc diffusion method and ESBL production was determined using a double-disc synergy test. The presence of CTX-M-type beta-lactamase genes was investigated through amplification using specific primers. The prevalence of CTX-M-type beta-lactamase was found 87% in E. coli isolates. The isolates displayed high rates of resistance to tested antibiotics: 87% to ampicillin-sulbactam (SAM), 77% to amoxicillin-clavulanic acid (AMC), 76% to co-trimoxazole (SXT), 70% to norfloxacin (NOR), 68% to ciprofloxacin (CIP), and 51% to gentamicin (GN). All isolates were found susceptible to imipenem (IPM), meropenem (MEM) and fosfomycin (FOS). Co-resistance was identified in 96% of isolates, and the most common two co-resistance phenotypes were AMC/SAM/GN/NOR/CIP/SXT (12%) and AMC/SAM/NOR/CIP/SXT (11%). CTX-M-type beta-lactamase was present in E. coli isolates at extremely high rates. The empiric therapy with SAM, AMC, SXT, NOR, CIP, and GN may not be adequately effective against certain isolates of E. coli due to high rate of resistance

CTX-M Type Beta-Lactamase Frequency and Antibiotic Co-resistance in Extended Spectrum Beta-Lactamase Producing Klebsiella pneumoniae Strains

Objective: Extended spectrum beta-lactamase-producing Klebsiella pneumoniae infections cause difficulties in antibiotic choice for treatment. In this study, the frequency of CTX-M type beta-lactamase, antibiotic resistance rates and co-resistance rates in extended spectrum beta-lactamase (ESBL)-producing K. pneumoniae strains isolated in our hospital were investigated. Material and Methods: A total of 107 K. pneumoniae strains isolated from various clinical specimens in 2007 were included in the study. Antibiotic susceptibility test was performed using disc diffusion method through the recommendations of Clinical Laboratory Standards Institute (CLSI). Double disk synergy test was used for detection of ESBL production. Carbapenemase production was determined with Modified Hodge test. Presence of the gene belonging to CTX-M type beta-lactamases was investigated with polymerase chain reaction method using primers specific to these sites. Results: Frequency of CTX-M type beta-lactamase was detected as 85%. In general, the isolates were found to be highly resistant to co-trimoxasole (SXT) (79%), ampicillin-sulbactam (SAM) (77%), amoxicillin-clavulanic acid (AMC) (68%) and nitrofurantoin (NIT) (52%), and they were found to be less resistant against amikacin (AK) (19%), ciprofloxacin (CIP) (21%), norfloxacin (NOR) (24%), gentamicin (GN) (31%), cefoperazone-sulbactam (SCF) (32%) and piperacillin-tazobactam (TZP) (37%). While the resistance against meropenem (MEM) and fosfomycine (FOS) which are among the most effective antibiotics was determined as 2% and 3% respectively, no resistance was found agaist imipenem. Co-resistance was detected in 90% of the strains and the most common two co-resistance phenotypes were found as AMC/SAM/SXT/NIT (9%) ye AMC/SAM/SXT (6.5%). Conclusion: CTX-M type beta-lactamases were found to be considerably high in K. pneumoniae strains. It was concluded that empirical treatments with these antibiotics could be insufficient in our region since resistance against SXT, SAM, AMC and NIT is high in ESBL producing K. pneumoniae strains

Co-expression of plasmid-mediated quinolone resistance-qnrA1 and bla(VEB-1) gene in a Providencia stuartii strain

An extended-spectrum beta-lactamase (ESBL)-producing Providencia stuartii isolate was studied. A qnrA1 gene co-expressing bla(VEB-1) gene was detected. Both genes were transferred to the recipient strain. The ciprofloxacin MIC of recipient strain increased tenfold. The bla(VEB-1) gene persisted in microorganisms in Turkey but it also spread with PMQR genes to other species. The combination of PMQR with multidrug resistant isolates producing ESBLs may compromise the use of valuable antibiotics. Serious efforts are necessary to detect PMQR determinants not only with common beta-lactamases in widespread pathogens but also with uncommon forms that are encountered infrequently

Determination of Escherichia coli and Citrobacter koseri Isolates with OXA-48 Carbapenemase in Istanbul

Objective: Today, carbapenems are used as almost last choice for the treatment of infections with extended spectrum beta-lactamase (ESBL) producing pathogens. However, the prevalence of carbapenamase-producing strains in Enterobacteriaceae has been increasing over the last decade. In this study, carbapenem-resistant Escherichia coli and Citrobacter koseri isolates with OXA-48 carbapenemase obtained from hospitalized patients in different regions of Istanbul were investigated. Material and Methods: The strains were identified by conventional methods and VITEK 2 system. Antibiotic susceptibility test was performed using disc diffusion method, and extended-spectrum beta-lactamase production was investigated using the double-disc synergy and cefotaxime/boronic acid- cefotaxime/boronic acid/clavulanic acid tests. VITEK 2 system was used for determination of minimum inhibitory concentration (MIC) of the antibiotics. The MICs of imipenem and meropenem for the clinical isolates were also determined by E-tests. The carbapenemase production was investigated with modified Hodge test. beta-lactamase genes and plasmid mediated quinolone resistance (PMQR) determinants were screened by polymerase chain reaction (PCR). The amplification products of bla(OXA-48) genes were sequenced. Conjugation experiment was used for transferring beta-lactamase gene. Results: The clinical isolates and their transconjugants were positive for bla(OXA-48), however, the isolates lacked PMQR and other beta-lactamase genes such as bla(TEM), bla(SHV), bla(CTX-M), bla(VIM), and bla(KPC). The bla(OXA-48) genes detected in both of the isolates were transferred to the recipient strain. The MICs were increased approximately two fold according to recipient strain in transconjugants for carbapenems. Additionally, the transconjugants conferred resistance to ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam and cefazolin. Conclusions: The carbapenemase-producing isolates may restrict the use of these valuable antibiotics. In Turkey, the bla(OXA-48) gene not only persists especially in ICIebsiella pneumoniae but also it has spread among other species. The presence of OXA-48 carbapenemase in rarely encountered species should also be considered

External decontamination of wild leeches with hypochloric acid

Background: Medicinal leech, Hirudo medicinalis, has been used in plastic and reconstructive surgery, to relieve venous congestion and to improve the microrevascularization of flaps. In many countries, wild leeches are still provided from local markets and utilised with antibiotic prophylaxies. In this research, results of identification of bacteria in the transport fluid is reported, oral and intestinal floras and the antibiograms of the identified microorganisms are investigated. Also, to avoid possible infections, the ability of hypochloric acid, a disinfectant, to suppress the relevant microorganisms without changing the life style and behavior of leeches in terms of sucking function, is investigated

Nasal carriage of methicillin-resistant Staphylococcus aureus in the children of hospital staff attending a day-care centre

Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen. Hospital staff with nasal carriage might transmit it to family members. We conducted this study to determine whether MRSA, acquired in the hospital environment, was a threat to the children of hospital staff. We obtained anterior nares cultures from 135 children, either one of whose parents was working in the hospital, who were attending the associated day-care centre. Three children with no history of previous hospital admission showed nasal carriage of MRSA. They were treated with topical mupirocin for 7 days. Cultures obtained after a drug-free 7 days revealed no growth. The mother and sister of a child were determined to be nasal carriers and they were treated with topical mupirocin. Our findings imply that children of hospital staff may be at risk for MRSA carriage. Med Sci Res 27:161-162 (C) 1999 Lippincott Williams & Wilkins