Ability of dynamic preload indices to predict fluid responsiveness in a high femoral-to-radial arterial pressure gradient: a retrospective study

Background@#Dynamic preload indices may predict fluid responsiveness in end-stage liver disease. However, their usefulness in patients with altered vascular compliance is uncertain. This study is the first to evaluate whether dynamic indices can reliably predict fluid responsiveness in patients undergoing liver transplantation with a high femoral-to-radial arterial pressure gradient (PG). @*Methods@#80 liver transplant recipients were retrospectively categorized as having a normal (n = 56) or high (n = 24, difference in systolic pressure ≥ 10 mmHg and/or mean pressure ≥ 5 mmHg) femoral-to-radial arterial PG, measured immediately after radial and femoral arterial cannulation. The ability of dynamic preload indices (stroke volume variation, pulse pressure variation [PPV], pleth variability index) to predict fluid responsiveness was assessed before the surgery. Fluid replacement of 500 ml of crystalloid solution was performed over 15 min. Fluid responsiveness was defined as ≥ 15% increase in the stroke volume index. The area under the receiver-operating characteristic curve (AUC) indicated the prediction of fluid responsiveness. @*Results@#Fourteen patients in the normal, and eight in the high PG group were fluid responders. The AUCs for PPV in the normal, high PG groups and total patients were 0.702 (95% confidence interval [CI] 0.553–0.851, P = 0.008), 0.633 (95% CI 0.384–0.881, P = 0.295) and 0.667 (95% CI 0.537–0.798, P = 0.012), respectively. No other index predicted fluid responsiveness. @*Conclusion@#PPV can be used as a dynamic index of fluid responsiveness in patients with end-stage liver disease but not in patients with altered vascular compliance.

Successful wire-guided fiberoptic nasotracheal intubation in a patient with hemifacial microsomia - A case report -

Background@#Patients with hemifacial microsomia may have a difficult airway due to the accompanying mandibular deformity. Fiberoptic bronchoscope-guided intubation is commonly used method for difficult airway management. However, awake fiberoptic nasotracheal intubation has several disadvantages, including difficulty in advancement of the endotracheal tube (ETT) due to the resistance between the ETT and bronchoscope. Wire-guided fiberoptic nasotracheal intubation may help to overcome the drawbacks of the conventional method.Case: An 18-year-old man with hemifacial microsomia was scheduled for double-jaw surgery. In preoperative evaluation, he had severe retrognathia and expected difficult airway. We successfully performed wire-guided fiberoptic nasotracheal intubation combined with high-flow nasal cannula and deep sedation without any complications. @*Conclusions@#A guidewire may be useful, in case of difficultly in advancing the ETT or if a smaller tube is required, while performing intubation with FOB in patients with difficult airways.

Accuracy and Efficacy of Impedance Cardiography as a Non-Invasive Cardiac Function Monitor

PURPOSE: The most common method of monitoring cardiac output (CO) is thermodilution using pulmonary artery catheter (PAC), but this method is associated with complications. Impedance cardiography (ICG) is a non-invasive CO monitoring technique. This study compared the accuracy and efficacy of ICG as a non-invasive cardiac function monitoring technique to those of thermodilution and arterial pressure contour. MATERIALS AND METHODS: Sixteen patients undergoing liver transplantation were included. Cardiac index (CI) was measured by thermodilution using PAC, arterial waveform analysis, and ICG simultaneously in each patient. Statistical analysis was performed using intraclass correlation coefficient (ICC) and Bland-Altman analysis to assess the degree of agreement. RESULTS: The difference by thermodilution and ICG was 1.13 L/min/m², and the limits of agreement were −0.93 and 3.20 L/min/m². The difference by thermodilution and arterial pressure contour was 0.62 L/min/m², and the limits of agreement were −1.43 and 2.67 L/min/m². The difference by arterial pressure contour and ICG was 0.50 L/min/m², and the limits of agreement were −1.32 and 2.32 L/min/m². All three percentage errors exceeded the 30% limit of acceptance. Substantial agreement was observed between CI of thermodilution with PAC and ICG at preanhepatic and anhepatic phases, as well as between CI of thermodilution and arterial waveform analysis at preanhepatic phase. Others showed moderate agreement. CONCLUSION: Although neither method was clinically equivalent to thermodilution, ICG showed more substantial correlation with thermodilution method than with arterial waveform analysis. As a non-invasive cardiac function monitor, ICG would likely require further studies in other settings.

Cardiac arrest due to intracranial hypotension following pseudohypoxic brain swelling induced by negative suction drainage in a cranioplasty patient: a case report / 대한마취과학회지

Pseudohypoxic brain swelling (PHBS) is known to be an uncommon event that may occur during and following an uneventful brain surgery, when negative suction drainage is used. The cerebrospinal fluid loss related to suction drainage can evoke intracranial hypotension that progress to PHBS. The main presentations of PHBS are sudden unexpected circulatory collapses, such as severe bradycardia, hypotension, cardiac arrest, consciousness deterioration and diffuse brain swelling as seen with brain computerized tomography (CT). We present a stuporous 22-year-old patient who underwent cranioplasty under general anesthesia. The entire course of the general anesthesia and operation progressed favorably. However, the time of scalp suture completion, sudden bradycardia and hypotension occurred, followed by cardiac arrest immediately after initiation of subgaleal and epidural suction drainage. After successful resuscitation, the comatose patient was transferred to the neurosurgical intensive care unit and PHBS was confirmed using brain CT.

Calcium/Calmodulin-Dependent Protein Kinase is Involved in the Release of High Mobility Group Box 1 Via the Interferon-beta Signaling Pathway

Previously, we have reported that high mobility group box 1 (HMGB1), a proinflammatory mediator in sepsis, is released via the IFN-beta-mediated JAK/STAT pathway. However, detailed mechanisms are still unclear. In this study, we dissected upstream signaling pathways of HMGB1 release using various molecular biology methods. Here, we found that calcium/calmodulin-dependent protein kinase (CaM kinase, CaMK) is involved in HMGB1 release by regulating IFN-beta production. CaMK inhibitor, STO609, treatment inhibits LPS-induced IFN-beta production, which is correlated with the phosphorylation of interferon regulatory factor 3 (IRF3). Additionally, we show that CaMK-I plays a major role in IFN-beta production although other CaMK members also seem to contribute to this event. Furthermore, the CaMK inhibitor treatment reduced IFN-beta production in a murine endotoxemia. Our results suggest CaMKs contribute to HMGB1 release by enhancing IFN-beta production in sepsis.

Modulation of protective immunity against herpes simplex virus via mucosal genetic co-transfer of DNA vaccine with beta2-adrenergic agonist

Cholera toxin, which has been frequently used as mucosal adjuvant, leads to an irreversible activation of adenylyl cyclase, thereby accumulating cAMP in target cells. Here, it was assumed that beta2-adrenergic agonist salbutamol may have modulatory functions of immunity induced by DNA vaccine, since beta2-adrenergic agonists induce a temporary cAMP accumulation. To test this assumption, the present study evaluated the modulatory functions of salbutamol co-administered with DNA vaccine expressing gB of herpes simplex virus (HSV) via intranasal (i.n.) route. We found that the i.n. co-administration of salbutamol enhanced gB-specific IgG and IgA responses in both systemic and mucosal tissues, but optimal dosages of co-administered salbutamol were required to induce maximal immune responses. Moreover, the mucosal co-delivery of salbutamol with HSV DNA vaccine induced Th2-biased immunity against HSV antigen, as evidenced by IgG isotypes and Th1/Th2-type cytokine production. The enhanced immune responses caused by co-administration of salbutamol provided effective and rapid responses to HSV mucosal challenge, thereby conferring prolonged survival and reduced inflammation against viral infection. Therefore, these results suggest that salbutamol may be an attractive adjuvant for mucosal genetic transfer of DNA vaccine.

Polarization of protective immunity induced by replication-incompetent adenovirus expressing glycoproteins of pseudorabies virus

Replication-incompetent adenoviruses expressing three major glycoproteins (gB, gC, and gD) of pseudorabies virus (PrV) were constructed and used to examine the ability of these glycoproteins to induce protective immunity against a lethal challenge. Among three constructs, recombinant adenovirus expressing gB (rAd-gB) was found to induce the most potent immunity biased to Th1-type, as determined by the IgG isotype ratio and the profile of the Th1/Th2 cytokine production. Conversely, the gC-expressing adenovirus (rAd-gC) revealed Th2-type immunity and the gD-expressing adenovirus (rAd-gD) induced lower levels of IFN-gamma and IL-4 production than other constructs, except IL-2 production. Mucosal delivery of rAd-gB induced mucosal IgA and serum IgG responses and biased toward Th2-type immune responses. However, these effects were not observed in response to systemic delivery of rAd-gB. In addition, rAd-gB appeared to induce effective protective immunity against a virulent viral infection, regardless of whether it was administered via the muscular or systemic route. These results suggest that administration of replication-incompetent adenoviruses can induce different types of immunity depending on the expressed antigen and that recombinant adenoviruses expressing gB induced the most potent Th1-biased humoral and cellular immunity and provided effective protection against PrV infection.

Flaviviruses Induce Pro-inflammatory and Anti-inflammatory Cytokines from Murine Dendritic Cells through MyD88-dependent Pathway

BACKGROUND: The genus Flavivirus consists of many emerging arboviruses, including Dengue virus (DV), Japanese encephalitis virus (JEV) and West Nile virus (WNV). Effective preventive vaccines remain elusive for these diseases. Mice are being increasingly used as the animal model for vaccine studies. However, the pathogenic mechanisms of these viruses are not clearly understood. Here, we investigated the interaction of DV and JEV with murine bone marrow-derived dendritic cells (bmDC). METHODS: ELISA and FACS analysis were employed to investigate cytokine production and phenotypic changes of DCs obtained from bone marrow following flavivirus infection. RESULTS: We observed that these viruses altered the cytokine profile and phenotypic markers. Although both viruses belong to the same family, JEV-infected bmDC produced anti-inflammatory cytokine (IL-10) along with pro-inflammatory cytokines, whereas DV infection induced production of large amounts of pro-inflammatory cytokines (IL-6 and TNF-alpha) and no IL-10 from murine bmDCs. Both flaviviruses also up-regulated the expression of co-stimulatory molecules such as CD40, CD80 and CD86. JEV infection led to down-regulation of MHC II expression on infected bmDCs. We also found that cytokine production induced by JEV and DV is MyD88-dependent. This dependence was complete for DV, as cytokine production was completely abolished in the absence of MyD88. With regard to JEV, the absence of MyD88 led to a partial reduction in cytokine levels. CONCLUSION: Here, we demonstrate that MyD88 plays an important role in the pathogenesis of flaviviruses. Our study provides insight into the pathogenesis of JEV and DV in the murine model.

Detection of Chlamydia pneumoniae in the Atherosclerotic Tissue by Immunohistochemistry / 대한임상병리학회지

BACKGROUND: Chlamydia pneumoniae is an important pathogen to cause approximately 5-10% of community-acquired respiratory infections and has been recently reported as a tentative causative agent of atherosclerosis in western countries. Considering that the most common cause of death is cerebral artery disease and coronary heart disease in Korea, we attempted to elucidate C. pneumoniae in atheromatous plaques. METHODS: Twenty-eight cases of atherectomy from 1996 to 1998, which included 20 patients with cerebral artery stenosis, two patients with carotid artery stenosis and six patients with coronary artery stenosis were prepared for immunohistochemistry to demonstrate C. pneumoniae. The Coronary arteries from 35 cadavers obtained were also stained with chlamydia genus-specific and C. pneumoniae-specific monoclonal antibodies. RESULTS: Eighteen of 20(90%) of cerebral artery stenosis, one of two of carotid artery stenosis and all six cases of coronary artery stenosis were positive for C. pneumoniae. Thirteen over 35(37.1%) cadavers presented arterial stenosis, while eight cases(61.5%) were positive for C. pneumoniae. CONCLUSIONS: This is the first report demonstrating C. pneumoniae in atheroma in Korea. In regard of the high positive rate of C. pneumoniae(89.3%) in cases of atherosclerosis, C. pneumoniae might be closely associated with atherosclerosis in Korea.

T Typing and Antimicrobial Susceptibility of Streptococcus pyogenes in Clinical Isolates / 대한임상병리학회지

BACKGROUND: As invasive streptococcal infections are increasing recently and the resistance rate to either erythromycin or clindamycin is elevating, epidemiologic surveillance and appropriate guideline for antibiotic use are required. Geographical epidemiologic characteristics with T typing and antibiotic resistance rate were investigated. METHODS: Distributions of T types according to geographical areas and sources of specimens were analyzed with 82 strains of Streptococcus pyogenes isolated from clinical samples in Seoul and Chinju. Antibiotic susceptibility test was performed for penicillin G, cephalothin, erythromycin, azithromycin, clarithromycin, clindamycin, chloramphenicol, and ofloxacin with agar dilution method. Antibiotic resistance rates were analyzed according to geographical areas, sources of specimens and T types. RESULTS: The most common T types were T12, T1 and T28 in decreasing order. The distribution of T types between Seoul and Chinju was different. While T1, T3, and T6 were frequent in throat or other respiratory specimens, T12, T28, and B3264 were common in blood or closed pus. The resistance rate to erythromycin, azithromycin, and clarithromycin was 20%, 13% to clindamycin, and 49% to tetracycline, respectively. None of the isolates were resistant to penicillin G, cephalothin, chloramphenicol, or ofloxacin. The isolates from Chinju showed higher resistance rate than the strains from Seoul. The isolates from blood or closed pus had higher resistance rate compared to those of throat or sputum. T28 and T6 strains presented higher resistance rate than other T types. CONCLUSIONS: As distributions of T types were variable according to geographical areas or sources of specimens, continuous microbiological and epidemiological surveillance for invasive streptococcal infections are needed. Minimizing unnecessary antibiotic use or acknowledging the severity of resistance are necessary, because the resistant proportions are increasing against macrolide, clindamycin and tetracycline.

Analysis of Chromosomal DNA of Shingella Isolates Using Pulsed-Field Gel Electrophorrsis / 대한임상미생물학회지

BACKGROUND: It is difficult to control an outbreak of Shigella infection, because of the ease of transmission and the resistance to multiple antibiotics. Recently, there were outbreaks of Shigella infection in Chinju area. The objective of this study was to investigate the molecular epidemiology of the outbreaks using pulsed-field gel electrophoresis(PFGE). METHOD: Thirteen S. flexneri strains, 25 S. sonnei strains from Chinju and 15 S. sonnei strains from Pusan were studied. All strains were isolated from stool cultures of diarrheal patients. Identification and antimicrobial susceptibility test those were tested by Vitek GNI and GNS-LH. Chromosomal DNA restricted with Xbal was resolved by PFGE. RESULT: All the S. flexneri strains and 23(92%)S. sonnei strains from Chinju were resistant to one or more antimicrobial agents. All the clinical isolates of S. flexneri showed the same PFGE pattern which was different from type strains(KTCC 2517). PFGE patterns of 25 (100%) S. sonnei strains from Chinju and 12 (80%) S. sonnei strains from Pusan were identical to those of type strain (KTCC 2009). Three S. sonnei strains from Pusan showed distinct PFGE patterns, respectively. CONCLUSION: PFGF demonstrated identical restriction pattern among most of Shigella isolates from Chinju and Pusan, indicating that an outbreak with genetically related strains had occurred. PFGE was useful in molecular epidemiology of Shigella outbreaks

Bacteriologic characteristics and serotypings of Streptococcus pyogenes isolated from throats of school children

To determine the carrier rate of beta-hemolytic streptococci (BHS), throat cultures were taken from healthy elementary school children in four separate areas of Korea from 1992 to 1995, including Inje, Nonsan, Seoul and Chinju. The strains of Streptococcus pyogenes had been serotyped with anti-T, -OF and -M sera. The isolation rates of BHS and S. pyogenes ranged from 14.1-32.4% and 10.9-18.5% respectively. More than half of the carriers showed heavy growth of BHS. M78 (48.6%) and M28 (22.2%) were most common in Inje, M12 (23.6%) and M5 (20.3%) in Nonsan, M12 (48.8%) and M5 (14.6%) in Seoul, and M12 (26.3%) and M22 (14.5%) in Chinju, respectively. About 15% of school children were positive for S. pyogenes in throat cultures, and the distribution of serotypes varied according to geographical regions.

M-Protein Genotyping and Exotoxin A Production of Group A Streptococci Isolated from Blood / 대한임상병리학회지

BACKGROUNDS: While M protein is the most important virulence factor of group A -hemolytic streptococci (GAS), the routine laboratories have difficulty to maintain more than 80 kinds of antibodies. emm gene encoding M protein has variable sequence at 5'-terminus according to each M type and is an appropriate target for molecular typing of GAS. Molecular epidemiologic analysis using emm gene sequencing and serological typing were conducted for GAS isolated from bacteremic patients. Also production of streptococcal pyrogenic exotoxin A (SPE A), a well known virulence factor in toxic streptococcal syndrome, and the frequency of speA and speB gene for the strains were observed. METHODS: Twenty-eight strains of GAS isolated from blood specimens were analyzed with serological or molecular typing. Serological typing including T antigen and serum opacity reaction was processed by standard methods. 5' region of emm PCR products was analyzed by automatic DNA sequencer. The obtained DNA sequences were matched with GenBank. Production of SPE A was confirmed by Western blot and the frequencies of spe genes were analyzed by PCR. RESULTS: All GAS strains were well classified into 13 kinds of different emm genotypes. emm13 (18%) was most common and emm1 and emm3 were three and two strains respectively. Discrepancy between T typing and emm genotyping was observed in two strains. speA gene and SPE A toxin were positive in six over 28 strains, of which emm types were emm1, emm3 and SP2346. CONCLUSION: In the distribution of emm genotypes of GAS isolated from blood, emm13 was the most common genotype, of which finding is quite different from the results of foreign countries. Virulent types such as emm1 (11%) and emm3 (7%) genotypes were not uncommon, which were positive in speA gene and SPE A toxin.

Detection of Chlamydia pneumoniae in Atherosclerotic Tissue on Electron Microscopy / 감염

BACKGROUND: Chlamydia pneumoniae is an obligate intracellular organism, which can cause respiratory tract infections, exacerbation of asthma, and possibly atherosclerosis. Detection of C. pneumoniae in the atherosclerotic tissue was made using electron microscopy to elucidate the correlation between C. pneumoniae and atherosclerosis. METHODS: Ten cases of paraffin-embedded atherectomy tissue, which were positive in the immunohistochemistry (IHC) were prepared to demonstrate C. pneumoniae on the electron microscope. Two cases of atherosclerotic tissue, which were negative in IHC were processed identically at the same time as negative controls. The tissues were embedded in resin, ultrathin-sectioned, and stained with uranyl acetate and lead citrate, and then observed on electron microscopy. RESULTS: Nine of 10 (90%) atherosclerotic tissue samples were positive for C. pneumoniae on electron microscopy. Negative controls did not show elementary bodies. Elementary bodies of C. pneumoniae were rarely observed in a scattered pattern in the positive specimens. CONCLUSION: Elementary bodies of C. pneumoniae could be demonstrated on electron microscopy in 9 out of 10 atherosclerotic tissue samples with positive IHC for C. pneumoniae. This finding suggests that C. pneumoniae may play an important role in atherogenesis.

Detection of ermAM Gene and mefA Gene in Erythromycin-resistant Streptococcus Pyogenes / 감염

BACKGROUND: The mechanism of erythromycin resistance of Streptococcus pyogenes results from target modification or active efflux. The purpose of this study was to determine the positive rate of ermAM gene modifying 23S rRNA and that of mefA gene related with efflux for erythromycin-resistant S. pyogenes. METHODS: The minimal inhibitory concentrations (MICs) of erythromycin, azithromycin, clarithromycin, and clindamycin against S. pyogenes were tested by agar dilution method. ermAM and mefA genes were amplified by polymerase chain reaction (PCR) for 32 strains of erythromycin-resistant S. pyogenes. RESULTS: Among the 32 erythromycin-resistant S. pyogenes strains, 20 (62.5%) strains were positive for ermAM gene and 10 (31.1%) for mefA gene. Eighteen (90.0%) out of 20 strains with ermAM gene showed high-level erythromycin resistance (MIC> OR =64 microgram/mL), while all ten strains with mefA gene had low-level erythromycin resistance (MIC< OR =16 microgram/mL). CONCLUSION: Two-thirds of the S. pyogenes strains acquired erythromycin resistance by modification of target site, while the others by active efflux. Each mechanism of resistance is closely associated with range of MICs of erythromycin.

Serial Evaluation of Serotypes of Group A Streptococci Isolated from Throat Culture of Normal School Children / 대한임상미생물학회지

BACKGROUND: Group A streptococci (GAS) cause various infections in the school children. The change of isolation rate of GAS between time interval was observed by repeated throat cultures and acquisition rate of new strain was investigated by comparing the serotypes of GAS. METHODS: Throat cultures were taken from the school children in Chungnam and Seoul. Second throat cultures were taken from 119 children in Chungnam after 1 month and from 59 children in Seoul after 4 months, who showed GAS in the first throat culture. Serotypings such as T, M and opacity factor typing were performed and compared against 40 children in Chungnam and 26 children in Seoul who grew GAS in both throat cultures. RESULTS: GAS were isolated from 57.1% (68/119) in Chungnam and 45.8% (27/59) in Seoul in the second throat culture. Different serotypes between first and second throat culture were 5 of 40 (12.5%) in Chungnam and 4 of 26 (154%) in Seoul, respectively. CONCLUSIONS: Almost half of children contained GAS continuously until 4 months and acquisition rate of new serotypes was 14.0% during this time. When GAS is repeatedly isolated, serotyping was very useful to recognize whether the strain is same or not.

Detection for Chlamydia trachomatis by Vidas Chlamydia Test and Direct Smear / 감염

BACKGROUND: Because Chlamydia trachomatis infection is the most frequent etiological agent in sexually transmitted diseases, accurate diagnostic methods are essential. The enzyme-linked fluorescence assay and Papanicolaou smear were evaluated for detection of C. trachomatis in patients with vaginitis. METHODS: Endocervical swabs from 78 women with symptoms of vaginal discharge, itching or lower abdominal pain in the obstetrics/gynecology department of Gyeongsang National University Hospital were tested by Vidas Chlamydia assay. Slides were stained with Papanicolaou and Giemsa stain to demonstrate inclusion body. RESULTS: Five (6.4%) of 78 endocervical specimens were positive by Vidas Chlamydia assay. Only one case was positve for C. trachomatis with Papanicolaou stain. We could not detect any C. trachomatis by Giemsa stain. CONCLUSION: The Vidas Chlamydia test allows sensitive and high-volume testing for chlamydiae and could be useful for the diagnosis of infection with C. trachomatis in patients with vaginitis and pelvic inflammatory disease.

Resurgence of Poststreptococcal Acute Glomerulonephritis in Chinju: Clinical Review of Recent 10 Years / 감염

BACKGROUND: Rheumatic fever(RF) or streptococcal invasive diseases have surged in developed countries recently. Incidence of poststreptococcal acute glomerulonephritis (PSAGN), a sequelae of group A streptococci (GAS) infection was investigated to evaluate the resurgence of PSAGN in Chinju. METHODS: Medical records of 90 patients with PSAGN from January 1988 were reviewed retrospectively. Annual incidence, clinical characteristics, and laboratory findings were analyzed. RESULTS: Annual incidence of PSAGN decreased until 1993, to as low as 0.09%, but started to increase in 1994 and became significantly high (1.83%) in 1996 (P<0.01). Most (64.6%) of PSAGN cases occurred from October to January. Major symtoms were edema (78.9%), gross hematuria (65.6%), oligura (22.2%), an fever (16.7%). Hypertension was observed in 28.9% during admission. Increse of ASO were observed in 92.0% (80/87), decrease of C3 and CH50 in 94.4% (85/90) and 93.2% (41/44), respectively. CONCLUSION: Annual incidence of PSAGN decreased until 1993, but increased from 1994. Whether this resurgence of PSAGN is merely regional or part of a national epidemic should be investigated.

Streptococcal Toxic Shock Syndrome Associated with Intrauterine Fetal Death: A Case Report / 대한임상미생물학회지

The group A streptococcus is capable of producing exotoxins that have been linked to a toxic shock-like syndrome. Streptococcal toxic shock syndrome is a rapidly progressive associated with injury to multiple organ systems and a 30-60% mortality rate. These cases are very rare in Korea. We present a case of 32-year-old prenant woman who developed streptococcal toxic shock syndrome following intrauterine fetal death. She manifestated hypotension, shock, increased level of creatinine, disseminated intravascular coagulopathy, liver impairment, renal failure, pulmonary edema and adult respiratory distress syndrome. Blood cultures yielded Streptococcus pyogenes. After 17 hours on admission, she died in spite of massive transfusion, antibiotics therapy and ventilatory support. Clinicians should be alert to the importance of early diagnosis and treatment of this lethal infection.

Throat Culture and Anti-OF Antibodies in the Elementary School Children / 대한임상병리학회지

BACKGROUND: Anti-OF (opacity factor) antibody (Ab) is useful to study past infection or outbreak of group A streptococci (GAS) and to identify OF antigen (Ag). Throat cultures were taken from 172 elementary school children and venous blood were collected at the same time to screen the frequency of anti-OF Ab. METHODS: The presence of OF Ag was recognized by turbidity of horse serum. OF Ag was identified with inhibition of opacity reaction by known anti-OF Ab. The sera of children were screened for the presence of anti-OF Ab with the representative OF Ag. RESULTS: The positive rate of anti-OF Ab was very high regardless of OF production or throat culture results. Thirty two of 38 (84%) OF Ag producing GAS carriers, 25 of 35 (71%) OF Ag non-producing GAS carriers and 72 of 99 (73%) throat culture negative children harbored anti-OF Ab. While among OF Ag, non-typable and OF 22 were high in prevalence (36.8% and 29.0% respectively), anti-OF 4, anti-OF 28 and anti-OF 12 of OF Ab were identified highly (39.5%, 29.7% and 15.7% respectively). Forty-five (26.2%) among 172 children had two anti-OF Abs and 11 (6.4%) had more than three anti-OF Abs. CONCLUSIONS: Seventy five percent of school children was proven to be previously infected with GAS through this anti-OF Ab study. The anti-OF Ab carrying rates were high, regardless of positivity of throat culture and OF Ag production. We could demonstrate that the prevalent strains of GAS changed in according to time span by proving the difference of frequency of OF Ag and anti-OF Ab and one-fourth of children had been infected with more than 2 different serotypes.