Frequency of isolation and antimicrobial susceptibility of bacteria isolated from bloodstream infections at Children's Medical Center, Tehran, Iran, 1996-2000

Antimicrobial susceptibility patterns of major bloodstream pathogens from Iran provide essential information regarding the selection of antibiotic therapy for patients with bloodstream infections (BSIs) living in Iran. Unfortunately, data regarding the isolation frequency and antimicrobial susceptibility patterns of endemic BSI pathogens are scarce in Iran. To shed some light on the susceptibility patterns of BSI pathogens endemic to Tehran, Iran, we investigated the antimicrobial susceptibility patterns of 2248 bloodstream isolates from patients in Children's Medical Center (CMC) Hospital in Tehran between January 1996 and December 2000. Microbiology reports of 24600 blood specimens collected from inpatients in CMC Hospital were retrospectively reviewed. Specimen culture, bacterial identification and disk diffusion susceptibility testing were performed according to National Committee for Clinical Laboratory Standards guidelines. Overall, Gram-positive bacteria comprised 72% (1627/2248) of recovered isolates and Gram-negative bacteria comprised 28% (621/2248). Coagulase-negative staphylococci (CoNS) comprised 48.4% of all isolates, followed by Staphylococcus aureus (16.7%) and Klebsiella spp. (8.5%). Among the 621 Gram-negative organisms, Klebsiella spp. (31%) were the most frequently isolated, followed by Escherichia coli (21%) and Pseudomonas aeruginosa (17%). The rates of oxacillin resistance for S. aureus and CoNS isolates were similar (60% versus 61%); however, the rate of S. aureus vancomycin resistance was almost twice that of CoNS resistance (21% versus 11%). Over 55% of S. pneumoniae were resistant to penicillin and co-trimoxazole. Although all isolates of enterococci were susceptible to vancomycin, only 21% were susceptible to gentamicin. Among Gram-negative isolates, amikacin was shown to be very effective, with susceptibility rates of 84%. The susceptibility of Klebsiella spp. to ampicillin and co-trimoxazole was 1% and 39%, respectively. The susceptibility of Klebsiella spp., E. coli and Enterobacter spp. to ceftriaxone was 47%, 86% and 67%, respectively. There were notable differences in the order of the five most common organisms isolated from blood cultures, which can help set priorities for focused control efforts. Our findings highlight the importance of a nationwide surveillance programme to monitor the trends in isolation frequency of bacteria and their antimicrobial resistance patterns throughout Iran.     

Lateral semicircular canal fenestration for congenital conductive hearing loss: Solution for a dilemma

Objective

To determine functional results after lateral semicircular canal fenestration on congenital conductive hearing loss.

Study Design

Case series with chart review.

Setting

Amir-Alam otolaryngology tertiary referral center.

Subjects and Methods

Twenty patients with congenital oval window malformations who were not candidates for ossicular reconstruction underwent lateral semicircular canal fenestration. A skin graft was placed over the perforated fascial graft on the fenestrated area.

Results

The median preoperative mean air conduction (MAC) was 56.9 dB (50.0 dB median air-bone). Postoperative median MAC gain of 34.3 dB (P < 0.001) and the median air-bone gap of 18.8 dB were observed. The mean bone conduction (MBC) did not show any significant changes postoperatively (P = 0.12). No sensorineural hearing loss, tinnitus, or imbalance was observed.

Conclusion

We demonstrated hearing improvement after lateral semicircular canal fenestration. This technique can be considered as an alternative for patients with middle ear anomalies who are not candidates for ossicular reconstruction.     

A case of tubulointerstitial nephritis in a patient with an influenza H1N1 infection

Background

Patients suffering from an H1N1 infection mainly suffer from respiratory symptoms but may also develop symptoms in other organ systems, such as the kidneys.

Case-diagnosis/treatment

A 4 ½?year-old boy was admitted with relatively mild respiratory symptoms of H1N1 infection, but developed severe generalized proximal tubular dysfunction with sterile leucocyturia and a reversible rise in serum creatinine. He made a full recovery with supportive therapy.

Conclusion

Influenza H1N1 may be associated with acute tubulointerstitial nephritis.     

Effect of surface treatment on stress distribution in immediately loaded dental implants—A 3D finite element analysis

Objective

To investigate, by means of FE analysis, the effect of surface roughness treatments on the distribution of stresses at the bone–implant interface in immediately loaded mandibular implants.

Materials and methods

An accurate, high resolution, digital replica model of bone structure (cortical and trabecular components) supporting an implant was created using CT scan data and image processing software (Mimics 13.1; Materialize, Leuven, Belgium). An anatomically accurate 3D model of a mandibular-implant complex was created using a professional 3D-CAD modeller (SolidWorks, DassaultSystèmes Solid Works Corp; 2011). Finite element models were created with one of the four roughness treatments on the implant fixture surface. Of these, three were surface treated to create a uniform coating determined by the coefficient of friction (μ); these were either (1) plasma sprayed or porous-beaded (μ = 1.0), (2) sandblasted (μ = 0.68) or (3) polished (μ = 0.4). The fourth implant had a novel two-part surface roughness consisting of a coronal polished component (μ = 0.4) interfacing with the cortical bone, and a body plasma treated surface component (μ = 1) interfacing with the trabecular bone. Finite element stress analysis was carried out under vertical and lateral forces.

Results

This investigation showed that the type of surface treatment on the implant fixture affects the stress at the bone–implant interface of an immediately loaded implant complex. Von Mises stress data showed that the two-part surface treatment created the better stress distribution at the implant–bone interface.

Significance

The results from this FE computational analysis suggest that the proposed two-part surface treatment for IL implants creates lower stresses than single uniform treatments at the bone–implant interface, which might decrease peri-implant bone loss. Future investigations should focus on mechanical and clinical validation of these FE results.     

Prevalence of IgA deficiency in children with juvenile rheumatoid arthritis

The purpose of this study was to investigate any association between IgA deficiency (IgAD) and juvenile rheumatoid arthritis (JRA) among Iranian children.This case-control study was carried out on 83 children who were diagnosed as JRA according to American College of Rheumatology (ACR) criteria; Patients were admitted at the rheumatology clinic of Children's Medical Center, (Tehran). Serum immunoglobulins concentrations were determined by nephelometry method. Control group was 112 healthy children who were matched for age and gender. Informed consent obtained from all parents.Selective IgA deficiency (sIgAD) was found only in a boy (1.2%) among JRA children; however, partial IgA deficiency was found in 6(7.1%) of patients with JRA and in 12(10.7%) of control subjects, this difference was not statistically significant (p=0.46). Immunoglobulins levels in patients with JRA (IgM: 126.7±57.2, IgG: 1182.3±351 and IgA:169.3±98) were significantly higher than their controls (IgM: 104±52, IgG:802±220 and IgA: 94.6±47) (p<0.05). Patients with growth failure had higher IgM, IgG and IgA levels in comparison with patients without growth failure; however, this difference was significant about IgM and IgG levels (p<0.05).In contrast to other similar studies, the number of IgAD did not differ significantly between JRA patients and their control counterpart; this might be partly due to the high rate of consanguineous marriages in Iran that resulted in increased prevalence of clinically undiagnosed partial IgAD in general population. Hence, future epidemiological studies are warranted to make it clear.     

A critique of the new ST-segment criteria for the diagnosis of acute myocardial infarction in patients with left bundle-branch block

BACKGROUND: Recently, electrocardiogram (ECG) criteria have been proposed for the diagnosis of acute myocardial infarction (AMI) in the presence of left bundle-branch block (LBBB). However, clinical experience indicates that such ECG changes indicative of AMI are occasionally noted in clinically stable patients with LBBB, raising concerns about the specificity of the proposed criteria. HYPOTHESIS: The aim of this study was to evaluate the frequency of ST-segment abnormalities suggestive of AMI in ambulatory patients with cardiovascular disease and chronic LBBB, who did not have an AMI. In addition, the ECG determinants of such ST-segment abnormalities were sought. METHODS: The files of all (4,193) patients followed in the outpatient cardiology clinic were reviewed to identify patients with LBBB. Electrocardiograms of these patients were evaluated as to the duration of the QRS complex, frontal QRS axis, amplitude of QRS in leads V1-V3, and the presence and magnitude of ST-segment depression (-ST) in leads V1-V3, and ST-segment elevation (+ST) in leads with predominantly positive or negative QRS complexes. Correlations of these ECG variables were carried out. RESULTS: In 124 patients with LBBB only 1 patient with -ST of 1 mm in leads V1-V3, and 1 patient with +ST of 1 mm in a predominantly positive ECG lead were found; the latter patient also had +ST of 6 mm in V3. Nine patients were detected with > or = 5 mm +ST in at least one ECG lead with predominantly negative QRS complex. Regression analysis of amplitude of +STs on corresponding QRS amplitudes in leads V1-V3 yielded Rs of 0.69, 0.68, and 0.69, all with a p value of 0.00005. A similar analysis of the amplitudes of +STs > or = 5 mm with the corresponding QRSs yielded an R = 0.76 and a p value of 0.0018. CONCLUSIONS: Thus, recently proposed ST-segment criteria for the diagnosis of AMI in patients with LBBB are appropriate. However, stable > or = 5 mm +STs are occasionally found in leads with predominantly negative QRS complexes, particularly of large amplitude (mean value 46.0, range [28.0-71.0] mm) in the absence of AMI. In such patients presenting with symptoms suggestive of AMI, further non-ECG confirmation of probable underlying AMI should be sought.     

Angiofibroma: an outcome review of conventional surgical approaches

Juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor of the nasopharynx, and for its treatment, many surgical approaches have been recommended. However, selecting the appropriate one for the tumor in an advanced stage is still controversial. In this study, we evaluate the rate of recurrence of JNA and its relationship to the preoperative stage as well as various surgical approaches. Thirty-seven patients with pathologically proven JNA were retrospectively analyzed. For each patient, data were obtained regarding the primary extension, various surgical approaches and rate of recurrence. Seven patients were in stage III with intracranial extensions. Two of these patients had symptomatic recurrence that needed surgery. Three of them were disease free, and in two cases residues were demonstrated that were asymptomatic and were chosen only to be observed. Among different surgical approaches used, the transpalatal resulted in 1 recurrence out of 14 patients treated with this approach when the lesion was limited to the nasal cavity, nasopharynx and paranasal sinuses (stage I). No recurrence was observed with the use of this approach with lesions with minimal extension to the pterygopalatine fossa (stage IIA). But among three patients with intracranial extension who were treated with this approach, two resulted in symptomatic recurrence; however, using the Lefort I surgical technique, no evidence of recurrence was observed in the two patients in stage III who were treated with this approach. Involvement of the orbit, middle cranial fossa and base of the pterygoid by the primary JNA results in a higher incident of recurrent tumor. Among different surgical techniques, the lowest recurrence rate is seen either in the transpalatal approach when the tumor is limited to the nasopharynx with extension to the nasal cavity or paranasal sinuses or with the Lefort I approach when skull base invasion is present.