[Investigation of SCCmec types and Panton-Valentine leukocidin in community-acquired and nosocomial Staphylococcus aureus strains: comparing skin and soft tissue infections to the other infections]. / Toplumdan Kazanilmis ve Nozokomiyal Staphylococcus aureus Suslarinda SCCmec Tiplerinin ve Panton-Valentine Lökosidin Varliginin Arastirilmasi: Deri ve Yumusak Doku Enfeksiyonlari ile Diger Enfeksiyonlarin Karsilastirilmasi

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are important health care problems since they are usually multidrug resistant. Although MRSA is isolated especially from nosocomial infections, community-acquired MRSA infections are increasing. Methicillin resistance is due to the expression of mecA gene, which is located on SCCmec gene cassette. Different SCCmec types can be detected in hospital-acquired and community-acquired (CA-) MRSA strains. CA-MRSA strains might harbour Panton-Valentine leukocidin (PVL), an important virulence factor in skin and soft tissue infections. Strains carrying PVL has the ability to penetrate undamaged skin and cause more severe infections. The aim of this study was to detect SCCmec types and PVL gene in S.aureus strains isolated from skin and soft tissue infections and to compare with strains isolated from other infections in a university hospital in Ankara, Turkey. S.aureus strains isolated from skin and soft tissue infections (n= 285) and a control group consisting of 161 strains isolated from other infections (53 blood, 48 lower respiratory tract samples, 30 sterile body fluids, 30 genitourinary tract samples) chosen by stratification and random selection method, were included in the study. Among skin and soft tissue infection strains 46.7% were from the hospitalized patients and 48.4% of skin and soft tissue infection strains were from female patients. The mean age of the skin and soft tissue infection patients was 45.5 years. Among the control strains 60.9% were from the hospitalized patients and 41.6% of the control patients were female. The mean age of the control patients was 50.2 years. Strains were identified by the Phoenix system (Becton Dickinson, USA) and identification was confirmed by tube coagulase test. Methicillin resistance was determined by the Phoenix system which determines both oxacillin and cefoxitin minimum inhibitor concentrations and, confirmed by oxacillin agar screening and/or cefoxitin disk diffusion test. All isolates were screened for the presence of mecA and PVL genes and SCCmec types were determined by PCR. MRSA constituted 20.3% (n= 58) of skin and soft tissue infection isolates and 24.2% (n= 39) of the control group. Of the 97 MRSA, 85 had a SCCmec type III-like pattern with an additional dcs region, three had type IV, three had type IIIa, one had type IIIb, one had type II and four could not be typed. The difference between SCCmec type distribution in skin and soft tissue infection and other infections' (control) groups was not statistically significant (p> 0.05). Two of the three SCCmec type IV strains were type IVa. Ten (2.2%) PVL positive strains, three of which were from the control group; were all methicillin susceptible S.aureus (MSSA). Although PVL positive MRSA was not common, detection of SCCmec type IVa, a marker for CAMRSA, and PVL positive MSSA strains which might act as a reservoir for PVL positive MRSA, indicated the importance of ongoing surveillance for MRSA.

[Investigation of macrolide-lincosamide-streptogramin B (MLS(B)) and telithromycin resistance in clinical strains of staphylococci]. / Stafilokok klinik izolatlarinda makrolid-linkozamid-streptogramin B (MLS(B)) ve telitromisin direncinin arastirilmasi.

The aim of this study was to determine the prevalence of macrolide-lincosamide-streptogramin B (MLS(B)) resistance and also to search for telithromycin resistance in staphylococcus strains isolated at Hacettepe University Hospital, Ankara, Turkey. A total of 381 Staphylococcus aureus isolates and 94 coagulase-negative staphylococci (CNS) were tested by disc approximation method. Methicillin resistance of these isolates was searched by disc diffusion test using 30 microg cefoxitin discs. Distribution of erm genes was detected by PCR method. Of 381 isolates 112 (29.4%) S. aureus and 58 (61.7%) CNS were found to be resistant to erythromycin. Among these, the inducible MLS(B) (iMLS(B)) resistance was the most prevalent pattern, being 56.2% and 41.4% among S. aureus and CNS isolates, respectively. The frequency of constitutive MLS(B) resistance (cMLS(B)) was 40.2% for S. aureus and 34.5% for CNS. Macrolide-streptogramin B (MS(B)) resistance pattern was detected only in CNS isolates (24.1%). In 4 (3.6%) of S. aureus isolates mixed pattern demonstrating both inducible and constitutive patterns was detected. None of the isolates susceptible to erythromycin showed resistance to telithromycin. As a remarkable finding of this study D-shaped inhibition zones around the telithromycin discs was observed in all of the isolates with iMLS(B) and macrolide-streptogramin B (MS(B)) resistance phenotypes. The isolates showing cMLS(B) pattern were also resistant to telithromycin (no zone of inhibition around the telithromycin discs). A total of 170 erythromycin resistant staphylococcal isolates were tested for the presence of erm and msrA genes. Among the S. aureus isolates with iMLS(B) and cMLS(B) phenoypes, the most common findings were the detection of ermA (44/63) and ermA + ermC (35/45) genes, respectively. All of the four isolates with mixed phenotype harboured ermA gene. With respect to CNS isolates, the most frequently detected gene was ermC (37/58); whereas iMLS(B) and cMLS(B) resistant CNS isolates had ermC (11/24) and ermA + ermC (10/20) as the most prevalent resistance genes, respectively. msrA gene was detected in 11 of 14 CNS isolates with MS(B) resistance. Two of these were also carrying ermA while 3 isolates harboured ermCalong with msrA gene. The results of this study showed that inducible MLS(B) resistance was the most prevalent phenotype among the clinical staphylococcal isolates in our hospital. All of these isolates also demonstrated inducible resistance pattern against telithromycin, a new antibiotic suggested particularly for the treatment of infections with iMLS(B) resistant bacteria. The telithromycin resistance patterns need to be tested in other centers and the impact of this issue on the clinical use of telithromycin should be investigated.

[In vitro activity of tigecycline against methicillin-resistant staphylococci]. / Metisiline dirençli stafilokoklarda tigesiklinin in vitro etkinliginin arastirilmasi.

Glycylcyclines are novel semisynthetic group of antibiotics that have been produced by substitution of glycylamido group at position 9 of tetracyclines. Tigecycline derived from minocycline is the first member of glycylcyclines. This new antibiotic has a broad spectrum of activity against variety of gram-positive and gram-negative bacteria and is not affected by known tetracycline resistance mechanisms. The aim of this study was to investigate the in-vitro activity of tigecycline as well as vancomycin, linezolid, quinupristin-dalfopristin and trimethoprim-sulphamethoxazole (TMP-SMX) against methicillin-resistant staphylococci isolated from clinical specimens of adult patients in Hacettepe University Hospital. For this purpose 127 Staphylococcus aureus (MRSA) and 42 coagulase negative staphylococci (MRCNS) which had been shown to be resistant to methicillin by disc diffusion method performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines, were evaluated. In these isolates minimum inhibitory concentration (MIC) values of tigecycline were detected by E-test; susceptibilities to linezolid, quinupristin-dalfopristin, TMP-SMX were detected by disc diffusion test. All of the isolates were searched for decreased susceptibility to vancomycin by agar screening method and MIC values of vancomycin were detected by E-test for the strains that grew on vancomycin agar plates. The range of MIC values of tigecycline were 0.032-1 microg/ml for the 127 MRSA isolates (MIC50 0.25 microg/ml, MIC90 0.75 microg/ml) and were 0.047-1 microg/ml (MIC50 0.25 microg/ml, MIC90 0.5 microg/ml) for the MRCNS isolates. All staphylococcal isolates were found to be susceptible to vancomycin, linezolid and quinupristin-dalfopristin. TMP-SMX resistance was detected in 7 (5.5%) MRSA and 26 (60.5%) MRCNS isolates. The results of this study demonstrated very good in-vitro activity of tigecycline against both MRSA and MRCNS isolates in our hospital. A remarkable finding of the present study was demonstration of the quite low rate of TMP-SMX resistance among MRSA isolates whereas MRCNS isolates showed high rate of resistance.

Nalidixic acid resistance in Salmonella strains with decreased susceptibility to ciprofloxacin isolated from humans in Turkey.

The aim of this study was to evaluate the value of nalidixic acid resistance as an indicator of decreased susceptibility to ciprofloxacin (MIC = 0.125 - 1 mg/L) in Salmonella isolates from humans (n = 620) in Turkey. One isolate was found to be resistant, and the remaining isolates were susceptible to ciprofloxacin with the Clinical and Laboratory Standards Institute breakpoints; however, 75 isolates (12.1%) had decreased susceptibility. Resistance to nalidixic acid was observed in 76 (12.3%) isolates in the disk diffusion test. Seventy-four of these isolates had decreased susceptibility, one was fully resistant, and one isolate was susceptible to ciprofloxacin. One isolate with decreased susceptibility to ciprofloxacin was intermediate to nalidixic acid. Screening with 30-microg nalidixic acid disks had a sensitivity of 98.6% and a specificity of 99.8% for determination of decreased susceptibility to ciprofloxacin.

Validation of urinary antigen test for Streptococcus pneumoniae in patients with pneumococcal pneumonia.

The study was undertaken to prospectively evaluate a Streptococcus pneumoniae urinary antigen test for diagnosis of pneumococcal pneumonia among patient and control groups between 2004 and 2006. Microbiological analysis for these patients included Gram staining for sputum, sputum and blood culture. Nonconcentrated urine samples were tested using an immunochromatographic assay, the NOW S.pneumoniae antigen test. The urinary antigen test was positive in 9 (15.3%) of 59 patients enrolled in the study and in 8 (73%) of 11 patients with pneumococcal pneumonia confirmed by conventional methods. The test revealed a sensitivity of 72.7% and a specificity of 97.6% with conventional microbiological criteria used as the reference standard. The positive predictive value was 88.9% and the negative predictive value was 93%. We concluded that the urinary antigen test can supplement conventional microbiological tests in the diagnosis of pneumococcal pneumonia.

[Anaerobic bacteria isolated from patients with suspected anaerobic infections]. / Anaerobik enfeksiyon süpheli hastalardan izole edilen anaerop bakteriler.

The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).

[The prevalence of nasopharyngeal Neisseria meningitidis carriage, serogroup distribution, and antibiotic resistance among healthy children in Cankaya municipality schools of Ankara province]. / Ankara ili Cankaya ilçesi okullarindaki saglikli cocuklarda nazofaringeal Neisseria meningitidis tasiyicilik prevalansi, serogrup dagilimi ve antibiyotik direnci.

Meningococci responsible for significant morbidity and mortality rates in children are found in the oropharynx and nasopharynx and communicated with droplets. In this study, the prevalence of nasopharyngeal Neisseria meningitidis carriage, serogroup distribution and antibiotic resistance were determined among healthy children in Cankaya municipality of Ankara province. The study involved 1155 students aged 7-19 years. Systematic sampling method was used for sample selection. To isolate N. meningitidis, modified Thayer-Martin medium was used. The antibiotic susceptibilities of N. meningitidis isolates were determined by agar dilution method for penicillin, sulfadiazine, rifampicin, and azithromycin. N. meningitidis carriage prevalence was found as 10.4% with serogroup B being the most predominant (47.5%). The prevalence of N. meningitidis carriage was found to be closely associated with living conditions however, tonsillectomy, tonsillar hypertrophy, passive or active smoking did not affect the rate of carriage. Overcrowded life style, use of old-fashioned stoves for heating, and living in shanty housing were determined as risk factors increasing N. meningitidis carriage. None of the strains showed beta-lactamase activity, and five strains (4.2%) had decreased sensitivity to penicillin. The resistance against sulfadiazine was 54.4%, while it was 26.9% against azithromycin. No rifampicin-resistant strain were detected. It can be concluded that the prevalence of meningococcal carriage in this study was similar to that of other European countries. Rifampicin should be the first drug of choice both for the treatment of meningococcal carriers and for the prophylaxis of the subjects who had been in contact with patients with meningococcal infection.

In vitro susceptibility, tolerance and MLS resistance phenotypes of Group C and Group G streptococci isolated in Turkey between 1995 and 2002.

A total of 105 clinical strains of Group C and Group G streptococci were examined for their susceptibility to penicillin, cefotaxime, erythromycin, meropenem and vancomycin using a broth microdilution method. Minimum bactericidal concentrations of the antimicrobial agents and phenotypes of strains resistant to erythromycin were also evaluated. No resistance to penicillin, cefotaxime, meropenem and vancomycin was found in years 1995-2002, but there was 6.7% resistance to erythromycin. No tolerance was seen for penicillin and vancomycin, but there were strains tolerant to cefotaxime, erythromycin and meropenem. The resistance phenotypes of erythromycin-resistant isolates were determined by the double disc test with erythromycin and clindamycin which showed inducible MLS (57.1%) and M phenotype (42.8%) resistance. This in vitro finding shows that classical antimicrobial agents used for the treatment of GCS and GGS have good activity against clinically significant isolates, but the presence of macrolide resistance and tolerant isolates suggests that careful surveillance of the streptococcal isolates should be carried out.

Evaluation of the Helicobacter pylori stool antigen test (HpSA) for the detection of Helicobacter pylori infection and comparison with other methods.

BACKGROUND/AIMS: Several invasive and non-invasive methods are available for the detection of H. pylori infection. The accuracy of anti-H. pylori antibodies in serum is low. There is a need for a quick, inexpensive and reliable non-invasive test to detect H. pylori. The aim of this study was to evaluate the enzyme immunoassay for the detection of H. pylori antigen in stool in the Turkish population and compare it to other methods. METHODOLOGY: 50 patients who were admitted to Hacettepe University Department of Internal Medicine, Division of Gastroenterology with the symptom of dyspepsia for whom the indication of upper gastrointestinal endoscopy was present were included in the study. With their permission stool samples were taken. The patients were evaluated with histology, culture, serology, rapid urease test and HpSA (Helicobacter pylori Stool Antigen test). Forty-one patients had gastritis and biopsies were taken from those. RESULTS: Excluding HpSA if three of the rest of four methods were positive, patients were accepted as H. pylori positive. Nineteen patients were positive for H. pylori, 22 were negative. HpSA was positive in 16 of 19. The sensitivity and specificity of the methods were as follows: histology 100% sensitive, and 86% specific, culture 63% and 100%, HpIgG 58% and 73%, rapid urease test 89% and 82%, respectively. The results were as 84% and 82% for HpSA. Comparing with the 'Gold Standard' histology using McNemar's test Kappa results were as 0.610, 0.181, 0.610, 0.708 for culture, HpIgG, Rapid Urease Test and HpSA, respectively. CONCLUSIONS: HpSA is a cheap, effective method for the diagnosis of H. pylori infection in the Turkish population.

[Six years evaluation of Clostridium difficile associated diarrhea]. / Clostridium difficile'ye bagli ishal olgularinin 6 yillik degerlendirmesi.

This study was aimed to detect the presence of Clostridium difficile toxin in the stool samples of patients with antibiotic-associated diarrhea or pseudomembranous colitis, and to relate its presence with the clinical findings of the patients. Between January 1997-April 2003, a total of 726 stool samples were investigated for C. difficile toxin A and/or B by enzyme immunoassay. Of them, 68 (9.4%) were found positive for C. difficile toxin (62 were toxin A, 6 were toxin B). C. difficile associated diarrhea were found to be related mostly with the use of beta-lactam/beta-lactamase inhibitor combinations (32/68), followed by aminoglycosides (12/68), and cephalosporins (8/68). The ages of the patients were between 1-86 years old (mean: 43.3 years), and 36 (52.9%) of them had an underlying conditions. Chronic obstructive pulmonary disease and chronic renal failure were the underlying disease in 18, malignancy in 11, and others (diabetes, hepatitis, transplantation, multiple sclerosis) in 7 of the patients. In conclusion, toxin detection and knowledge of the risk factors are the beneficial guidelines for the diagnosis of C. difficile associated diarrhea in the routine setting.

[Comparison of the value of disk diffusion methods and polymerase chain reaction for fixation of methicillin resistant staphylococcus]. / Stafilokoklarda metisilin direncinin saptanmasinda disk difüzyon yönteminin degeri ve polimeraz zincir reaksiyonu ile karsilastirilmasi.

The detection of methicillin resistance with an appropriate method has a great importance in the treatment of infectious diseases caused by staphylococci. This study was set out to compare disk diffusion method as a phenotypic method, with polymerase chain reaction (PCR), as a genotypic method, for the detection of methicillin resistance in staphylococci. A total of 406 staphylococci strains that were isolated from clinical specimens in microbiology laboratories of adult hospital of Hacettepe University Medical Faculty were included into the study. Of 406 strains, 248 were identified as Staphylococcus aureus, and 158 were coagulase-negative staphylococci (CNS). When the disk diffusion test was compared to PCR for the detection of methicillin resistance, sensitivity and specificity were found as 100% for S. aureus (respectively, 106/106 and 142/142), whereas for CNS sensitivity was 100% (86/86) and specificity was 79% (57/72). For CNS, if zone diameter for resistance was accepted as < or = 14 mm instead of < or = 17 mm, all of the mecA positive strains were found as resistant, whereas three mecA negative strains appeared to be resistant by disk diffusion method [sensitivity: 100% (86/86), specificity: 95.8% (69/72)]. Although disk diffusion was found as a reliable method for the detection of methicillin resistance in S.aureus isolates, it couldn't show the same success in CNS. For that reason in order to obtain the zone diameter for CNS, further studies are needed.

[Determination of serologic markers against bacterial atypical pneumonia agents in pneumonia patients]. / Pnömonili hastalarda bakteriyel atipik pnömoni etkenlerinin serolojik olarak degerlendirilmesi.

Approximately one third of all community acquired pneumonia cases are caused by Legionella pneumophila, Mycoplasma pneumoniae and Chlamydophila pneumoniae (previously, Chlamydia pneumoniae) which are known as bacterial atypical pneumonia agents. Serological tests are used commonly for laboratory diagnosis of these agents. The aim of this study was to evaluate the causative role of bacterial atypical pneumonia agents in clinically diagnosed pneumonia patients. Acute and convalescent serum samples were collected from a total of 65 clinically diagnosed adult pneumonia patients in order to evaluate IgM and IgG positivities against L. pneumophila, M. pneumoniae and C. pneumoniae. IgM and IgG were evaluated by enzyme immunoassay (ELISA) for L. pneumophila and M. pneumoniae, and by indirect fluorescent antibody (IFA) method for C. pneumoniae. In acute serum samples, 4 (6.2%) M. pneumoniae IgM positivity in addition to 3 (4.6%) L. pneumophila IgG, 3 (4.6%) M. pneumoniae IgG and 62 (95.4%) C. pneumoniae IgG positivity were detected. In convelescent serum samples, 3 (4.6%) L. pneumophila, 1 (1.5%) M. pneumoniae, 3 (4.6%) C. pneumoniae IgM positivity and 4 (6.2%) L. pneumophila with 1 (1.5%) M. pneumoniae IgG positivity were detected in addition to acute sample positivities. According to these serological data, totally 16 (24.6%) of the patients were infected by bacterial atypical pneumonia agents. These results show that bacterial atypical pneumonia agents are important etiological factors for community acquired pneumonia.

[Salmonella enterica serotypes and Salmonella infections: a multicenter study covering ten provinces in Turkey]. / Salmonella enterica serotipleri ve Salmonella enfeksiyonlari: Türkiye'de on ili kapsayan çok merkezli bir çalisma.

In order to find the distinctive features of Salmonellae and Salmonella infections in Turkey, 620 Salmonellae strains, isolated from various clinical samples (481 stool, 108 blood, 12 urine, 3 bone marrow, 3 cerebrospinal fluid, 9 pus, and one from each of the bile, pleural fluid, wound, catheter samples) in 13 clinical microbiology laboratories of 10 provinces in Turkey (Ankara, Antalya, Bursa, Edirne, Eskisehir, Istanbul, Izmir, Kayseri, Konya and Trabzon) between July 1, 2000 and June 30, 2002, were serotyped. Among the patients 43% were female, 57% were male, 63.2% were from outpatient clinics and 36.8% were hospitalized patients. Seventy eight percent of the patients had gastroenteritis, 10.7% had septicemia/local infection, 9.8% had typhoid/paratyphoid fever and 1.5% were carriers. Incidence of gastroenteritis was higher in 0-5 years age group (p<0.001). Of the 620 Salmonella enterica isolates, 47.7% were S. Enteritidis, 34.7% S. Typhimurium, 6% S. Paratyphi B, 2.9% S. Typhi, 0.2% S. paratyphi A, 6.1% serogroup C1, and 2.4% serogroup C2. S. Enteritidis was the most common serotype in all provinces except for Kayseri, where S. Typhimurium was found to be the most common serotype (68.2%). Overall, the most frequently isolated serotype was S. Enteritidis, also being the most common serotype in stool and blood cultures. During the surveillance period two outbreaks have occurred, the first one by S. Enteritidis strains in Edirne, and the second one by S. Typhimurium strains in Kayseri. As a result, Salmonella infections are still a common health problem in Turkey, and active surveillance of Salmonella infections has vital importance.

Does granulocyte-macrophage colony-stimulating factor prevent bacterial translocation in rats with surgical trauma and obstructive jaundice?

BACKGROUND/AIMS: The incidence of sepsis can be decreased by preventing bacterial translocation, as the first step in enhanced host defense. The aim of this study was to prevent translocation and to increase Kupffer cell incidence by using granulocytemacrophage colony-stimulating factor in rats with surgical trauma and obstructive jaundice. METHODS: Seventy-five Sprague- Dawley rats were randomized into 8 groups. After calibration of laboratory conditions by Group 0, SHAM operations in Groups I, II, IIA and common bile duct ligations in Groups III, IV, IVA and V were performed. Granulocyte-macrophage colony- stimulating factor doses were 6 microg/kg/d in Groups II, IV; 1 microg/kg/d in IIA, IVA postoperatively; and 6 microg/kg/d in Group V preoperatively, for 7 days. After one week, all rats were reoperated for cecal lymph node, liver and spleen biopsies for culture and histopathology. All culture specimens were identified as positive/negative/contaminated. Survivals were recorded, and after the 21st day surviving rats were sacrificed by decapitation. RESULTS: There was no translocation in Group 0 in the three specimens of liver, cecal lymph node and spleen. Group V showed minimal (10%) positivity in only liver, and other groups ranged between 20-70% in cecal lymph node, liver and spleen tissues, respectively (p<0.05). Kupffer cell incidences were higher in the granulocyte-macrophage colony-stimulating factor given groups than in controls, and lower in common bile duct ligation groups than in SHAM groups (p<0.001). Groups 0 and V showed the best (median 20 days) and Group III the worst (median 11.7 days) survival (p<0.001). CONCLUSIONS: Not only surgical trauma but also obstructive jaundice caused high incidence of translocation, decreased number of Kupffer cells and shortened survival. Translocation ratios were decreased by granulocyte- macrophage colony-stimulating factor in the SHAM and common bile duct ligation groups. Granulocyte-macrophage colony- stimulating factor prevented the decrease in Kupffer cell incidence caused by jaundice and prolonged the survival by preventing translocation at the first step.

Rapid 4 to 6 hour detection of extended-spectrum beta-lactamases in a routine laboratory.

With the growing frequency of extended-spectrum beta-lactamases (ESBL) among Enterobacteriaceae, treatment of Gram-negative nosocomial infections requires rapid and reliable detection of this enzyme. Quicolor agar (QC agar) (Salubris Inc., Massachusetts, USA) is a novel chromogenic agar medium changing colour within 4 to 6 h due to the metabolic activity of growing bacteria. This study investigated the use of QC agar compared to Mueller Hinton agar (MH) for the detection of ESBL using disk diffusion and E-test. 100 Enterobacteriaceae isolated at Hacettepe University Hospital, of which 50 were predetermined to be ESBL positive and 50 as negative using the CLSI disk diffusion ESBL (phenotypic confirmatory test) criteria. For disk diffusion and E-test, cefotaxime+/-clavulanate (CT/CTL) and ceftazidime+/-clavulanate (TZ/TZL) were used, and for E-test, cefepime+/-clavulanate (PM/PML) was also used. QC agar rapid ESBL results for all strains were in agreement with the standard overnight procedure. All 50 ESBL positives were detected by both methods. For the 50 ESBL negatives, QC agar rapid results from E-test and disk diffusion were in complete accordance with the overnight MH results. Moreover, E-test detected 8 additional ESBL positive strains that disk diffusion missed. For disk diffusion, CT/CTL alone detected all 50 ESBL positives while TZ/TZL alone missed 5 ESBL positives. E-test CT/CTL alone confirmed all 50 ESBL positives and identified 4 additional ESBL-positive strains. When used together, E-test CT/CTL, TZ/TZL and PM/PML identified a total of 58 ESBL positives among the 100 strains tested. QC agar can be used for rapid and reliable ESBL detection within 4 to 6 h, using disk diffusion and E-test ESBL reagents. This rapid method should be further validated using genotype characterized ESBL and other beta-lactamase positive strains.

Macrolide resistance mechanisms and in vitro susceptibility patterns of viridans group streptococci isolated from blood cultures.

OBJECTIVES: Our aim was to study the macrolide resistance mechanisms and antimicrobial susceptibilities of viridans group streptococci (VGS) isolated from blood cultures. METHODS: In vitro susceptibilities to nine antimicrobials were studied for 85 VGS isolated from blood cultures by agar dilution. Pheno- and genotyping of erythromycin-resistant isolates were studied by the double disc test and PCR. RESULTS: Resistance to erythromycin was found in 27% (n = 23) of the isolates. Erythromycin-resistant Streptococcus oralis (n = 13) predominated among the other erythromycin-resistant species isolated. The phenotypes among 23 erythromycin-resistant isolates were as follows: 12 constitutive macrolide-lincosamide-streptogramin (cMLS(B)) resistance phenotype and 11 macrolide (M) resistance phenotype. Of the cMLS(B) isolates 11 had erm(B) genes and 11 of the M phenotype isolates had mef(A) genes. Four of the cMLS(B) isolates had both erm(B) and mef(A) genes. None of the isolates had erm(TR) genes. Combined resistance to erythromycin with penicillin, clindamycin, chloramphenicol, tetracycline and quinupristin/dalfopristin was found in 100, 61, 74, 100 and 100% of the isolates, respectively. No resistance was found for vancomycin, linezolid and levofloxacin. CONCLUSIONS: The macrolide resistance mechanisms of our VGS isolates revealed that the cMLS(B) phenotype associated with erm(B) and the M phenotype associated with mef(A) genes are found with similar frequencies.

Methicillin-resistant Staphylococcus aureus heterogeneously resistant to vancomycin in a Turkish university hospital.

OBJECTIVES: We investigated vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneously vancomycin-intermediate S. aureus (hetero-VISA) isolates from clinical specimens of hospitalized patients at Hacettepe University over a 4 year period. METHODS: Strains were screened for VISA and hetero-VISA by using brain heart infusion agar containing 4 mg/L vancomycin (BHI-V4) and macro Etest. Confirmation of the isolates that were found to have intermediate susceptibility to vancomycin with either of the methods was done by population analysis of subpopulations with reduced susceptibility to vancomycin. The MIC of vancomycin for the isolates grown on BHI-V4 was determined by the microdilution method. RESULTS: Among 256 methicillin-resistant S. aureus (MRSA) isolates, 145 grew on BHI-V4. Forty-six of these were also found to be heterogeneously vancomycin-intermediate strains when screened with the macro Etest. There were no VISA among 256 MRSA tested but 46 (17.97%) S. aureus strains with reduced susceptibility to vancomycin were identified by population analysis. Vancomycin MIC values for all isolates with reduced susceptibility were between