Bengül Durmaz

Bacteriological, clinical and epidemiological characteristics of hospital-acquired Acinetobacter baumannii infection in a teaching hospital

Over an 18 month period, the bacteriological, clinical and epidemiological characteristics of nosocomial Acinetobacter baumannii infections in a teaching hospital were studied. Typing studies were performed on 38 strains isolated from 36 patients. Twenty-two of the strains were isolated during the three outbreaks. Surgery, catheterization, mechanical ventilation, and antibiotic therapy for adult patients and respiratory distress syndrome, mechanical ventilation, and prematurity for paediatric patients were the main risk factors identified. All isolates were resistant to penicillins (except ampicillin-sulbactam), cephalosporins, gentamicin, and aztreonam but susceptible to carbapenems and colistin. Resistance to tobramycin, ciprofloxacin, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, and amikacin was variable. Antibiotyping, arbitrarily-primed polymerase chain reaction (AP-PCR) and the pulse-field gel electrophoresis (PFGE) indicated the epidemiological relationship. The outbreak strains, demonstrated genetic distinction between our three outbreaks and isolates from specific areas in the hospital.

Bacteriology of chronic maxillary sinusitis and normal maxillary sinuses: using culture and multiplex polymerase chain reaction.

Background Although many investigations have been performed on bacteriology of chronic sinusitis and normal sinuses, there still is much discussion. Also a new bacterial agent, Alloiococcus otitidis determined in the nasopharynx and middle ear specimens can be thought as a causative agent of sinusitis. Methods The bacteriology of chronic maxillary sinusitis and maxillary sinuses with normal radiogram and endoscopic findings were studied by culture methods for aerobic and anaerobic bacteria. Multiplex polymerase chain reaction (PCR) was used to investigate four bacteria in study and control groups. There were 27 specimens in the study group and 28 specimens in the control group. Results In the study group, the bacteria commonly isolated were Staphylococcus aureus (11.1%), α-hemolytic streptococci (11.1%), Streptococcus pneumoniae (11.1%), Haemophilus influenzae (7.4%), coagulase-negative staphylococci (7.4%), and anaerobes (33.3%). Coagulase-negative staphylococci (14.3%), α-hemolytic streptococci (10.7%), and anaerobes (35.7%) were isolated also in the control group. PCR was used to investigate S. pneumoniae, H. influenzae, Moraxella catarrhalis, and A. otitidis in the study and control groups. None of these bacteria was determined in the control group whereas detection rates of these bacteria in the study group were 11.1, 11.1, 3.7, and 7.4%, respectively. It should be considered that PCR yielded faint amplification band for A. otitidis. Conclusion Using multiplex PCR can help to increase detection rates of bacterial etiology. Healthy sinuses are not sterile. A. otitidis may be one of the pathogens causing sinusitis.

Methicillin-resistance among Turkish isolates of Staphylococcus aureus strains from nosocomial and community infections and their resistance patterns using various antimicrobial agents

The purposes of this study were to determine the prevalence of Turkish isolates of methicillin-resistant Staphylococcus aureus (MRSA) in nosocomial and community infections and their antibiotic resistant patterns. The oxacillin disk diffusion method for the detection of methicillin resistance and the Kirby-Bauer disk diffusion for antibiotic susceptibility tests were used. A total 383 S. aureus strains were identified from different patients. The prevalence of methicillin resistance among S. aureus strains was 31.3% (120/383). The proportions of MRSA isolated from nosocomial and community infections were 26.4% (46/174) and 35.4% (74/209), respectively. The resistance rates of MRSA to other antibiotics were as follows: 71% resistant to erythromycin, 54% to clindamycin, 52% to gentamicin, 44.5% to trimethoprim-sulfamethoxazole and 36% to ciprofloxacin. No strain resistant to vancomycin was recorded in this study.

Prevalence of Group A Streptococcal Carriers in Asymptomatic Children and Clonal Relatedness among Isolates in Malatya, Turkey

ABSTRACT In our study, the prevalence of nasopharyngeal Streptococcus pyogenes was 130 (14.3%) of 909 healthy children. Isolates were found to be susceptible to all antibiotics tested. Pulsed-field gel electrophoresis and arbitrarily primed PCR revealed that 34 (32.4%) of the 105 isolates and 41 (40.6%) of the 101 isolates typed, respectively, were clonally indistinguishable.

Primary Drug Resistance and Molecular Epidemiology of Mycobacterium tuberculosis Isolates from Patients in a Population with High Tuberculosis Incidence in Turkey

To determine the rate of primary drug resistance and compare the fingerprint pattern diversity of the resistant and sensitive Mycobacterium tuberculosis isolates, antituberculosis susceptibility testing and restriction fragment length polymorphism (RFLP) analysis were performed on 88 M. tuberculosis isolates of the patients who were diagnosed as new tuberculosis cases in 2000. Primary resistance to isoniazid, rifampicin, ethambutol, and streptomycin were determined by the BACTEC method. IS6110 and pTBN12 were used as molecular markers. The frequency of resistance to at least one drug was 32.95%, whereas 10.23% of the isolates were resistant to more than one drug. Single-drug resistance to isoniazid, streptomycin, ethambutol, and rifampicin was found in 9 (10.22%), 7 (7.95%), 4 (4.54%), and 0 (0.0%) strains, respectively. Two M. tuberculosis strains (2.26%) showed multiple drug resistance. The combination of two fingerprinting procedures on a total of 88 isolates identified 58 (65.9%) strains as unique and clustered 30 strains in 11 clusters (clustering = 34.1%). The clustering rate for resistant and sensitive isolates was 13.8% and 40.1%, respectively. In conclusion; drug susceptibility testing showed that the majority of the drug-resistant infections involved either isoniazid or streptomycin alone. In addition to the high tuberculosis incidence, elevated primary drug resistance and high clustering rate indicate problems in the present control programs. New control strategies supported by molecular typing might be more effective to reduce tuberculosis.

Nosocomial infections in a new medical center, Turkey.

Nosocomial infection was found in 255 (2.5%) of 10,164 inpatients in a new medical center with a 310-bed capacity. The infection rate was 12.5% in the intensive care unit, 9.5% in neurology, 5.5% in general surgery, and 4.0% in orthopedics. Rates in the other services were lower. Hospital-acquired infections in our medical center frequently involved multiply resistant Enterobacteriaceae and staphylococci.

Detection and Typing of Extended-Spectrum β-Lactamases in Clinical Isolates of the Family Enterobacteriaceae in a Medical Center in Turkey

To determine and type the extended-spectrum beta-lactamases (ESBLs) among the family Enterobacteriaceae in a medical center, a total of 668 clinical isolates were screened. Of the 668 isolates, the 80 strains were presumptively defined as ESBL producers according to the result of disk method using ESBL marker antibiotics (aztreonam, ceftazidime, and cefoxitin). These 80 strains were retested with the double-disk synergy test (DDST), the E-test ESBL strip, a 5-microg ceftazidime disk, and agar dilution MICs of ceftazidime with and without clavulonic acid. Isoelectric focusing was performed to confirm ESBL production and type the beta-lactamases. By evaluation of the results of all tests used for ESBL detection together with isoelectric focusing, 33 (4.9%) of the 668 isolates were described as ESBL producer. The positive results of the agar dilution test, DDST, the E-test strip, and 5-microg ceftazidime disk were 32, 26, 27, and 26 of the 33 strains, respectively. ESBL positivity was 48.8% in Klebsiella species, 15.4% in Citrobacter species, 4.9% in Enterobacter species and 1.1% in Escherichia coli strains. The ESBL enzymes frequently determined were SHV-2/6-like (pI 7.6), SHV-5-like (pI 8.2), SHV-4-like (pI 7.8), and SHV-3-like (pI 7). SHV-derived enzymes were commonly observed in Klebsiella spp whereas TEM-related enzymes were seen in E. coli strains. The results of this study indicated that SHV-2/6-derived (pI 7.6) ESBL expression among the isolates of the family Enterobacteriaceae is an important problem in our medical center.

Sensitivity of two-stage PCR amplification for detection of Mycobacterium tuberculosis in paraffin-embedded tissues

In order to improve the sensitivity of polymerase chain reaction (PCR) for the detection of mycobacterial DNA in paraffin-embedded tissues, a new approach with two sets of specific primers in two-stage PCR was employed in specimens obtained from tuberculosis patients and controls. Thirty-nine paraffin blocks selected from patients who had been diagnosed as having tuberculosis by radiological evaluations, histopathological findings, and clinical symptoms and signs including response to antituberculous treatment were examined. The control group consisted of 10 specimens from individuals that were proved to be negative for tuberculosis. After deparaffinization, lysis, phenol–chloroform extraction, and ethanol precipitation, the isolated DNA was amplified by PCR. Initially, all specimens were examined by the one-stage PCR using specific primers for 123-base pair (bp) fragment in IS6110 of mycobacterial DNA which yielded positive results only in 3 out of 39 (7.7%). In the two-stage PCR technique, 245-bp fragment of mycobacterial DNA was amplified at the first-step, then the PCR products were reamplified using the second specific primer pairs for 123-bp fragment. The true positivity of the two-stage PCR was 84.6% (33/39). The results indicate that two-stage PCR is more sensitive than one-stage (84.6% vs. 7.7%). All control specimens were negative by both PCR amplification methods, indicating that specificity of both methods was high. When the two-stage amplification was used, PCR positivity in the specimens obtained from different tissues was as follows: peritoneal and omental biopsies, 4/4; bone biopsies, 3/3; lymph node biopsies, 12/14; genito–urinary biopsies, 7/9; skin biopsies, 4/6; and one from each lung, breast, and pleural biopsies. PCR showed a good correlation with the granulomatous tissue reaction resulting in a 83.8% (31/37) positivity. The results indicate that the two-stage PCR amplification can be used for detection of M. tuberculosis in paraffin-embedded tissues and is a useful technique in confirming tuberculosis in patients with clinically suspected disease who have acid-fast stain-negative.