High-level aminoglycoside resistance and distribution of aminoglycoside resistance genes among Enterococcus spp. clinical isolates in Tehran, Iran.

OBJECTIVES: Enterococci have gained attention during the past decade as important nosocomial pathogens. Their increasing prevalence has been paralleled by the occurrence of multidrug-resistant and high-level aminoglycoside-resistant strains. This study isolated Enterococcus spp. from hospital samples and determined their antibiotic resistance profile, focusing on aminoglycosides, and associated resistance mechanisms. METHODS: A total of 195 enterococci from hospital samples in Tehran were studied. Isolates were identified by biochemical reactions. Antimicrobial resistance was determined by disk diffusion. The vancomycin MIC for vancomycin-resistant isolates was determined by agar dilution. Detection of aminoglycoside resistance genes and intI1 and intI2 gene was performed by PCR. RESULTS: The majority of isolates were Enterococcus faecalis (65.1%), followed by Enterococcus faecium (31.8%), Enterococcus gallinarum (2.6%) and Enterococcus solitarius (0.5%). According to antibiogram results, 42.1% of isolates were high-level gentamicin-resistant (HLGR) and 40.5% were high-level streptomycin-resistant (HLSR). There was a high prevalence of aac(6')-Ie-aph(2")-Ia (96.3%) among HLGR isolates. ant(6)-Ia and aadA were identified in 93.7% and 64.6% of HLSR isolates, respectively. aph(2'')-Ic was detected in 7 isolates (3.6%) and aph(2'')-Ib in only 4 isolates (2.1%); no isolates harboured aph(2'')-Id, intI1 or intI2. CONCLUSION: Multidrug resistance was higher among HLGR and HLSR isolates compared with non-HLGR and non-HLSR isolates, which may result in limited treatment options. More than 50% of isolates were susceptible to aminoglycosides, thus correct identification in clinical laboratories and administration of these antibiotics can result in decreased used of antibiotics such as vancomycin and linezolid and help to reduce the emergence of resistance to these drugs.

Design of a multiplex PCR method for detection of toxigenic-pathogenic in Vibrio cholerae.

OBJECTIVE: To study virulence and regulatory genes (hlyA, ctxB, tcpI) in clinical strains of Vibrio cholerae (V. cholerae), simultaneously. METHODS: Three important genes, tcpI, hlyA and ctxB were used for detection of toxigenic and pathogenic V. cholera by chain reaction assay method. RESULTS: According to the results of the PCR, the incidence of hlyA, tcpI, and ctxB genes in clinical isolates was obtained as 94.7% (72 sample), 90.8% (69 sample), and 92.1% (70 sample), respectively. Five strains possessed all genes except ctxB, six strains possessed all genes except tcpI, four strains possessed all genes except hlyA, one strain possessed only hlyA and 60 strains contained a combination of three genes, Including hlyA, ctxB and tcpI. CONCLUSIONS: Result show that this method could be reliable to detect toxigenic-pathogenic strains of V. cholerae in Iran.

Design of a multiplex PCR method for detection of toxigenic-pathogenic in Vibrio cholerae

OBJECTIVE@#To study virulence and regulatory genes (hlyA, ctxB, tcpI) in clinical strains of Vibrio cholerae (V. cholerae), simultaneously.@*METHODS@#Three important genes, tcpI, hlyA and ctxB were used for detection of toxigenic and pathogenic V. cholera by chain reaction assay method.@*RESULTS@#According to the results of the PCR, the incidence of hlyA, tcpI, and ctxB genes in clinical isolates was obtained as 94.7% (72 sample), 90.8% (69 sample), and 92.1% (70 sample), respectively. Five strains possessed all genes except ctxB, six strains possessed all genes except tcpI, four strains possessed all genes except hlyA, one strain possessed only hlyA and 60 strains contained a combination of three genes, Including hlyA, ctxB and tcpI.@*CONCLUSIONS@#Result show that this method could be reliable to detect toxigenic-pathogenic strains of V. cholerae in Iran.

Linezolid vancomycin resistant Enterococcus isolated from clinical samples in Tehran hospitals.

BACKGROUND: Vancomycin-resistant enterococci pose an emerging health risk. The limitation in therapeutic options has resulted in the development of new drugs such as quinupristin/ dalfopristin and linezolid. AIM, SETTING AND DESIGN: This study investigated the species prevalence and antibacterial resistance among enterococci isolated in selected Tehran hospitals. MATERIALS AND METHODS: Between March 2006 and August 2007, 200 enterococcal isolates from urine, blood, stool and wound were recovered in 2 teaching hospitals of Tehran province. Susceptibility of all isolates was tested against vancomycin, teicoplanin and linezolid antibiotics by disk diffusion and agar dilution method. RESULTS AND CONCLUSION: Seventeen (8.5%), 6 (3%) and 4 (2%) of the isolates were resistant to vancomycin, teicoplanin and linezolid, respectively. Within the vancomycin-resistant isolates, 6 (35.2%), 4 (25%) and 1 (5.88%) showed vanA, vanB and vanC genotype patterns, respectively. Four (23.5%) of VRE isolates were resistant to linezolid with minimum inhibitory concentrations between 16 and 32 microg/mL. Two linezolid vancomycin resistant enterococci were E. faecium.

Assessment of middle ear disease in the dog: a comparison of diagnostic imaging modalities.

OBJECTIVES: To compare radiography and ultrasound for the assessment of the tympanic bulla against computed tomography results. METHODS: Thirty-one dogs had dorsoventral, left and right lateral oblique and rostrocaudal open mouth radiographs compared with ultrasound images and computed tomography scans of the tympanic bullae. RESULTS: Radiography was superior to ultrasonography for the evaluation of the middle ear. However, computed tomography assessment was best predicted by a combination of radiographic and ultrasonographic findings. CLINICAL SIGNIFICANCE: A combination of radiography and ultrasound can provide a more accurate assessment of the bulla than either of them alone. Ultrasound may have a role in the evaluation of middle ear disease in the dog. Results are operator dependent and not reproducible with current recording techniques.

Comparison of ultrasonography, radiography and a single computed tomography slice for fluid identification within the feline tympanic bulla.

Evaluation of the tympanic bulla (TB) in cases of acute feline otitis media can be a diagnostic challenge, although a feature often associated with this condition is the accumulation of fluid or material within the middle ear cavity. A technique is reported allowing optimum imaging of the feline TB using ultrasound (US) and recording of the appearance of gas and fluid-filled TB. A random number of bullae in 42 feline cadavers were filled with lubricant and rostroventral-caudodorsal oblique radiographs, single slice computed tomography (CT) images and US images were created and interpreted by blinded operators. The content (fluid or gas) of each TB was determined using each technique and the cadavers were then frozen and sectioned for confirmation. CT remained the most accurate diagnostic method, but US produced better results than radiology. Given the advantages of US over other imaging techniques, these results suggest that further work is warranted to determine applications of this modality in the evaluation of clinical cases of feline otitis media.

Diagnosis and surgical treatment of a nasopharyngeal cyst in a dog.

A 21-month-old boxer dog was presented with clinical signs caused by nasopharyngeal obstruction. A mineralised mass in the nasopharynx was identified by radiography. Computed tomography allowed accurate anatomical localisation of the cystic lesion and identification of an ossified wall. Surgical removal of the mass by a ventral approach resulted in complete resolution of clinical signs. Histopathological examination strongly suggested that the cyst was derived from remnants of Rathke's pouch.

Ultrasonographic diagnosis of unusual portal vascular abnormalities in two cats.

Two cases of ascites secondary to portal vascular abnormalities associated with portal hypertension are described. In the first case a five-month-old cat was presented with recurrent ascites and investigations showed that the underlying cause was a hepatic arteriovenous fistula. Ultrasonography showed direct communication of the coeliac artery and right branch of the portal vein. There was also hepatofugal flow in the main portal vein consistent with portal hypertension. The ultrasonographic features were similar to those seen in dogs with hepatic arteriovenous fistulae. In the second case, ascites, portal hypertension and an intraluminal mass in the main portal vein was diagnosed in a 16-year-old cat that had been presented with hyperthyroidism and hepatomegaly. Acquired portosystemic collaterals involving the left renal vein were present. Additional diagnostic investigations were not permitted. Ultrasonography was useful in both cases to document portal hypertension and the underlying cause.

Comparison of ultrasonography, radiography and a single computed tomography slice for the identification of fluid within the canine tympanic bulla.

Fluid accumulation within the tympanic bulla (TB) is an important diagnostic indicator in clinical cases of canine otitis media although its identification can be a challenge using currently available imaging techniques. The aim of this study was to compare ultrasound with radiography and a single computed tomography (CT) slice for the identification of fluid within the TB of canine cadavers. A random number of TB in 66 cadavers were filled with ultrasound gel. Rostrocaudal open mouth (RCdoM) radiographs and CT images were interpreted by 2 blinded radiologists and ultrasound examinations were performed by 2 blinded sonographers. The heads were then frozen and sectioned to confirm the contents of each TB. Although CT remained the most accurate method, comparable results were obtained by one of the sonographers and even the inexperienced sonographer produced results superior to radiography. Ultrasound has several advantages over the other imaging techniques and this study suggests that it may have an application in the investigation of canine otitis media although further work in live animals would be required to confirm this.

Ultrasound imaging of the canine tympanic bulla.

A procedure for imaging the canine tympanic bulla, external ear canal and adjacent structures using currently available ultrasound equipment was established. Lateral and ventral transducer positions were identified for this purpose and a 6.5 MHz curvilinear transducer was considered to be optimal. The sonographic appearance of these structures in cadavers and live dogs unaffected by ear disease is documented. Fluid was introduced into the tympanic bullae of the cadavers and its presence could be identified through the bony wall of the bulla. The ability of ultrasound to differentiate between gas and fluid within the bulla has important clinical implications as this is a common occurrence in dogs with middle ear disease. Ultrasound has several advantages over other imaging modalities and the examination procedure was well tolerated by unsedated dogs.

Evaluation of once daily treatment with cyclosporine for anal furunculosis in dogs.

Twenty-four dogs with anal furunculosis were treated with cyclosporine once daily for 13 weeks at dosages of 1.5, 3.0, 5.0 or 7.5 mg/kg, and re-examined after six and 12 months. After 13 weeks the disease in six of the dogs was in remission, 11 were controlled or improved and seven had failed to respond. The response of the dogs given the highest dose was significantly better than the response of the other groups taken together (P < 0.014), and better than the responses of the groups given 1.5 mg/kg and 5 mg/kg (P < 0.05). The dogs improved clinically during the treatment, most rapidly during the first five weeks. Of the six dogs that were in remission after 13 weeks, three relapsed after one, two and six months. The 11 dogs that were improved or controlled after 13 weeks were either left untreated or were continued on cyclosporine medication for one to three months at a dosage of 1.5 to 7.5 mg/kg; the disease went into remission in four cases and remained controlled in the other seven, but four of the 11 cases relapsed during the 12 months following the treatment. The side effects observed included increased coat turnover and transient vomiting.

Proliferation responses in preimmunized mice lymphocytes by Bordetella pertussis cell wall components.

Bordetella pertussis infects the respiratory tract of the human host and causes whooping cough in children. The nature of immunity against Bordetella pertussis infection and disease is poorly understood. The aim of this study was to investigate cell mediated immunity in mice immunized with outer membrane component of cell wall, of B. Pertussis. A group of mice were immunized with outer membrane complex (OMC) and killed whole cell (WCV) of B. pertussis, with an interval of 2 weeks. During a period of 7 weeks following the immunization, lymphocytes were isolated from lymph nodes of immunized mice. The in vitro proliferative response of isolated lymphocyte to stimulation with 20 ig of 30 and 69 kDa outer membrane protein (OMP) were measured as parameters for cell mediated immunity (CMI). The data were expressed as mean count per minute (CPM)x103 after subtraction of the CPM of unstimulated control cultures. Lymphoblastogenic response was observed in immunized mice with WCV and OMC. At 30 days of post immunization a significant increase in response to 30 and 69 kDa OMP was observed, a small decrease in the response was evident against P30 and P69 at 60 and 120 days of post immunization, but the response was still higher than what was observed in control mice. Current findings indicate strongly the potential of outer membrane protein component of B. perlussis in proliferating lymphocytes in the mice.