A rapid simultaneous antigen detection of Haemophilus influenzae and Streptococcus pneumoniae for predicting the prognosis of acute otitis media.

BACKGROUND: Rapid identification of causative bacteria in treatment of acute otitis media (AOM) is of paramount importance for appropriate antibiotic use. MATERIALS AND METHODS: This prospective observational study was conducted in 15 hospitals and clinics in Japan between 2018 and 2020. A new rapid antigen test kit (AOS-116), which simultaneously detects antigens for Streptococcus pneumoniae (Sp) and Haemophilus influenzae (Hi), was applied for middle ear fluids (MEFs) and nasopharyngeal secretions (NPSs) in patients with moderate to severe AOM. We investigated relationship between the results of rapid test, severity at initial visit, and clinical course. RESULTS: Regarding performance accuracy based on culture results, AOS-116 showed 1) high (>80%) sensitivity, specificity, and negative predictive value (NPV) in MEFs for both antigens, 2) high sensitivity, specificity, and positive predictive value (PPV) in NPSs for Hi antigen, and 3) high specificity, and PPV in NPSs for Sp antigen. Regarding predictive value of nasopharyngeal culture and antigen detection for causative middle ear pathogens, similar results were observed between AOS-116 and culture, which was characterized with high sensitivity and NPV for both pathogens. MEFs/NPSs positive for Hi antigen were significantly associated with eardrum findings, and severity. MEFs/NPSs positive for pneumococcal antigen were significantly associated with severity of otalgia, fever, and otorrhea. Among patients with prior antimicrobial treatment, improvement tended to be slower in cases positive for Hi than in cases negative. CONCLUSION: The rapid antigen detection test is useful as a decision-making tool for prescribing antimicrobial agents and may play an important role in promoting appropriate antimicrobial use.

Microbiology of Acute Maxillary Sinusitis in Children.

OBJECTIVES/HYPOTHESIS: Acute rhinosinusitis is a frequent common cold-related complication in children. Despite the need for appropriate treatment, its underlying microbiology remains unclear. This study aimed to investigate the microbiology of acute rhinosinusitis in children. STUDY DESIGN: Prospective non controlled study. METHODS: Thirty-one pediatric acute maxillary sinusitis patients with severe symptoms were assessed. The subjects were 17 males and 14 females aged 5 to 14 years (mean age, 9.1 years). Maxillary sinus aspirates were collected and cultured, with subsequent viral and bacterial polymerase chain reaction (PCR) analysis. Bacteria were analyzed using culturing and PCR, and viruses were analyzed using PCR. The PCR kits used identify 18 types of respiratory viruses and 13 types of bacteria. RESULTS: At least one pathogen was detected in 30 of 31 aspirates (97%) using PCR, and none of the aspirates contained respiratory viruses alone. Ten aspirates (32%) contained both viruses and bacteria. The most common viruses detected were rhinovirus (13%) and influenza virus (10%). The most common bacteria were Haemophilus influenzae (45%), Streptococcus pneumoniae (32%), Moraxella catarrhalis (16%), and Chlamydophila pneumoniae (13%). Bacteria were found in 21 of 31 cases (68%) via bacterial culturing. Culturing revealed that H influenzae was the most common pathogen (42%). CONCLUSIONS: In pediatric acute maxillary sinusitis, respiratory bacteria were detected in 65% of the sinus aspirates and both bacteria and viruses in 32%. The most common viruses were rhinovirus and influenza virus, and the most common bacteria were H influenzae and S pneumoniae. Viral and bacterial PCR is useful for accurately investigating the microbiology in pediatric sinusitis. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2705-E2711, 2021.

Features predicting treatment failure in pediatric acute otitis media.

OBJECTIVES: To facilitate better antibiotic stewardship, we conducted this clinical trial to identify the prognostic features of treatment failure in pediatric acute otitis media (AOM). STUDY: Design: This is a randomized, parallel-group, open-label, comparative clinical trial. SUBJECTS AND METHODS: Children with AOM and aged between 1 month and 5 years were enrolled. Patients were randomly assigned to receive either amoxicillin alone (70 mg/kg) for five days, or the same with additional clarithromycin (15 mg/kg) for the initial three days. The clinical course of AOM was evaluated based on tympanic membrane scores. Failure of treatment for AOM was confirmed on day 14. Nasal conditions were also assessed by a clinical scoring system for acute rhinosinusitis. RESULTS: Treatment failures occurred in 25 out of 129 (19.4%) children. The ratio of treatment failures by age was significantly higher in children younger than 2 years than in children older than 2 years. The tympanic membrane scores on day 3 (P = 0.0334) and day 5 (P < 0.0001) and acute rhinosinusitis scores on day 5 (P = 0.0004) were higher in failure cases than in cured cases. Multivariate logistic regression analysis indicated significant associations between the treatment failure with tympanic membrane scores and acute rhinosinusitis scores on day 5, and the antimicrobial treatment regimen. CONCLUSIONS: Improvement of acute rhinosinusitis and tympanic membrane scores on day five were important predictive features in failure of treatment for pediatric AOM. These results will be useful when discussing the treatment decisions with the patient's parents.

Sensitivity surveillance of Pseudomonas aeruginosa isolates for several antibacterial agents in Chubu area (2013-2014).

We investigated the susceptibility to antibacterial agents of 186 clinical isolates of Pseudomonas aeruginosa isolated from medical facilities in Gifu, Aichi, Toyama, and Fukui prefectures from October 2013 to February 2014. MIC50/90 of piperacillin (PIPC), tazobactam/piperacillin (TAZ/PIPC), ceftazidime (CAZ), cefepime (CFPM), imipenem (IPM), meropenem (MEPM), doripenem (DRPM), aztreonam (AZT), ciprofloxacin (CPFX), levofloxacin (LVFX), amikacin (AMK) and colistin (CL) against P aeruginosa was 8/32, 4/32, 2/8, 2/16, 1/32, 0.5/8, 0.25/4, 8/32, 0.25/8, 0.5/16, 4/8 and 1/1pg/mLrespectively. Two strains of multidrug resistant P aeruginosa were isolated (1.1%). They were isolated from the respiratory tract, intra-abdominal, and urinary infection. The susceptible ratio against P aeruginosa derived from intra-abdominal infection for carbapenem was lower than those from respiratory tract and urinary infection. The susceptible ratio against P aeruginosa derived from urinary infection for penicillin, cephem, monobactam, and fluoroquinolone was lower than those from respiratory and intra-abdominal infection. It is meaningful to pay attention to the susceptibility to antibacterial agents in each clinical specimen from infected organ.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibacterial agents in Gifu and Aichi prefectures (2011-2012)].

We investigated the susceptibility to antibacterial agents, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, and the serotypes against 270 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between October 2011 and April 2012. These results were compared with those against S. pneumoniae isolated in 2008-2009 and 2010-2011. The number of gPSSP with 3 normal PBP genes, gPISP with 1 or 2 normal PBP genes and gPRSP with 3 abnormal genes isolated in 2011-2012 was 15 (5.6%), 162 (60.0%) and 93 (34.4%) strains, respectively. Compared with those isolated in 2008-2009 and 2010-2011, the numbers of gPRSP were decreasing. On the other hand, the isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 16 (5.9%), 75 (27.8%), 153 (56.7%) and 26 (9.6%). Compared with those isolated in 2008-2009 and 2010-2011, the numbers of isolates with ermB, which was usually associated with high-level resistance, were increasing. The prevalent pneumococcal serotypes in children were type 3 (14.4%), following by type 15 and 19F (9.3%). The coverages of 7-valent pneumococcal conjugate vaccine (PCV7) and 13-valent pneumococcal conjugate vaccine (PCV13) were calculated as 22.9% and 49.2%, respectively. The coverages of PCV7 and PCV13 in gPRSP isolated from children were 47.7% (21/44 strains) and 72.7% (32/44 strains). The MIC90 of each antibacterial agent was as follows; 0.125pg/mL for imipenem, panipenem and garenoxacin, 0.25 µg/mL for meropenem and doripenem, 0.5 µg/mL for cefditoren, moxifloxacin and tosufloxacin, 1 µg/mL for amoxicillin, clavulanic acid/amoxicillin, cefteram, cefcapene and ceftriaxone, 2 µg/mL for benzylpenicillin, ampicillin, sulbactam/ampicillin, piperacillin, tazobactam/piperacillin and levofloxacin, 4 µg/mL for cefdinir, flomoxef and pazufloxacin, 16 µg/mL for minocycline, > 64 µg/mL for clarithromycin and azithromycin, and these MIC90s were about the same as those in 2010-2011.

[Antimicrobial activity of several drugs against extended-spectrum beta-lactamase positive Enterobacteriaceae isolates in Gifu and Aichi prefecture].

We investigated the antimicrobial activity of several drugs against 131 extended-spectrum beta-lactamase (ESBL) positive clinical isolates in Gifu and Aichi prefecture from 2007 to 2011. Meropenem (MEPM) and doripenem (DRPM) gave the lowest MIC50 at 0.0313 microg/mL. MEPM gave the lowest MIC90 at 0.0625 microg/mL. According to the Clinical and Laboratory Standards Institute breakpoints, the susceptible rates of carbapenems, tazobactam/piperacillin (TAZ/PIPC) and cefmetazole (CMZ) were higher than 90%. The susceptible rates of MEPM, DRPM, imipenem (IPM), TAZ/PIPC and CMZ were 98.5%, 98.5%, 94.7%, 94.7% and 92.4%. We used the PCR method and identified the molecular types of the ESBL positive isolates. Seventy-two strains had CTX-M-9 group gene and CTX-M-9 group gene is the most frequently detected. Against the CTX-M-9 group gene harboring strains which were the most common in our investigation, the susceptible rates of TAZ/PIPC, MEPM, DRPM and IPM were 100%. It is suggested that not only carbapenems but also TAZ/PIPC and CMZ are useful against infections caused by ESBL positive isolates.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibacterial agents in Gifu and Aichi prefecture (2010-2011)].

We investigated genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, the serotypes and the susceptibility to antibacterial agents against 258 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between January 2010 and March 2011. These results were compared with those against 377 strains of S. pneumoniae isolated in 2008-2009. The number of genotype penicillin-susceptible S. pneumoniae (gPSSP) with 3 normal PBP genes, genotype penicillin-intermediate S. pneumoniae (gPISP) with 1 or 2 normal PBP genes and genotype penicillin-resistant S. pneumoniae (gPRSP) with 3 abnormal genes was 11 (4.3%), 135 (52.3%) and 112 (43.4%) strains, respectively. The isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 17 (6.6%), 65 (25.2%), 143 (55.4%) and 33 (12.8%). The prevalent pneumococcal serotypes isolated from children were type 19F (18.2%), following by type 6A and 15 (11.7%). The potential coverage of pneumococcal conjugate vaccine (PCV7) was 43.8%. The prevalent pneumococcal serotypes isolated from adults were high in order of type 19F (12.8%), type 6A, 3 and 11 (10.3%), excepting non-typable strains (17.9%), and from elderly persons were type 6B (23.2%) and type 3 (13.4%). The MIC90 of each antibacterial agents was as follows; 0.0625 microg/mL for garenoxacin, 0.125 microg/mL for panipenem, 0.25 microg/mL for imipenem, doripenem, tosufloxacin, 0.5 microg/mL for cefditoren, meropenem, moxifloxacin, 1 microg/mL for amoxicillin, clavulanic acid/amoxicillin, cefteram, cefcapene, ceftriaxone, 2 microg/mL for benzylpenicillin, piperacillin, tazobactam/ piperacillin, pazufloxacin, levofloxacin, 4 microg/mL for cefdinir, flomoxef, 16 microg/mL for minocycline, > 64 microg/mL for clarithromycin, azithromycin and these MIC90s were about the same as those in 2008-2009.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibacterial agents in Gifu and Aichi prefecture (2008-2009)].

We investigated the susceptibility to antibacterials, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, and the serotypes against 377 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between June 2008 and April 2009. These results were compared with those against 160 strains of S. pneumoniae isolated in 2004. Referring to CLSI (M100-S17), the overall incidence of penicillin-susceptible (PSSP), penicillin-intermediate (PISP) and penicillin-resistant (PRSP) S. pneumoniae was 143 (38%), 185 (49%) and 49 (13%) strains, respectively. PISP and PRSP were isolated higher in the material of nasal cavity and throat, and PRSP was isolated higher in the area of Chuno district. The number of gPSSP with 3 normal PBP genes, gPISP with 1 or 2 normal PBP genes and gPRSP with 3 abnormal genes was 23 (6.1%), 173 (46%) and 181 (48%) strains, respectively. The isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 28 (7.4%), 138 (37%), 166 (44%) and 45 (12%). The prevalent pneumococcal serotypes were type 19 (92 strains; 24%), following by type 23 (60 strains; 16%) and type 6 (56 strains; 15%). The 80% of pneumococcal serotypes of PRSP were serotype 19 and 6. The MIC90 of each antibacterial was as follows; 0.1 microg/mL for imipenem, panipenem and garenoxacin, 0.2 microg/mL for moxifloxacin, 0.39 microg/mL for meropenem and tosufloxacin, 0.78 microg/ mL for amoxicillin, clavulanic acid/amoxicillin, cefditoren and cefcapene, 1.56 microg/mL for benzylpenicillin, piperacillin, cefteram and levofloxacin, 3.13 microg/mL for cefotiam, flomoxef and pazufloxacin, 6.25 microg/mL for cefdinir, 12.5 microg/mL for norfloxacin and minocycline, > 100 microg/mL for clarithromycin, and these MIC90s were about the same as those in 2004.

[Sensitivity surveillance of Pseudomonas aeruginosa isolates for several antibacterial agents in Gifu and Aichi prefecture (2008)].

We investigated the susceptibility to antibacterial agents of 334 strains of Pseudomonas aeruginosa isolated from medical facilities in Gifu and Aichi prefectures from May to September 2008. For the beta-lactams, meropenem (MEPM) and doripenem (DRPM) gave the lowest MIC50 at 0.5 microg/mL, and tazobactam/piperacillin (TAZ/PIPC) gave the highest susceptible rate of the breakpoint by Clinical and Laboratory Standards Institute (CLSI) at 93.1%. For the quinolones, ciprofloxacin (CPFX) gave the lowest MIC50 at 0.25 microg/mL, followed by pazufloxacin (PZFX) at 0.5 microg/mL, and levofloxacin (LVFX) at 1 microg/mL, and susceptible rate was 76.0% for CPFX and 73.4% for LVFX. Susceptible rates to amikacin (AMK) and tobramycin (TOB) of aminoglycocides and colistin (CL) of polypeptides were 98.2%, 97.6% and 96.4%. In 334 strains, IMP-1 MBL producing P. aeruginosa was 1 strain, and the strain showed resistance to all antibacterial agents except AMK and CL used in this study. The strains isolated from urine were lower susceptible rate in comparison with those from sputum, notably the susceptible rate to CPFX from urine was less over 30% than those from sputum. Because the results of the susceptibility test against P. aeruginosa were different in each area, it is important for us to pay attention to the susceptibility to antibacterial agents and the emergence of resistance in the clinical strains through continuous susceptibility surveillance.

[Epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture and the northern district of Aichi prefecture--2009].

High pathogenicity and drug resistance of Streptococcus pneumoniae are serious problem in clinical practice. Since 1999, we have conducted epidemiologic analyses of S. pneumoniae in Chubu district. We report the results of the analysis conducted in 2009. Three hundred and eight (308) S. pneumoniae isolates with a gene coding for autolysin lyt-A, which had been isolated from patients at 21 medical institutions in Gifu prefecture and the northern part of Aichi prefecture in 2009, were enrolled in this study. The strains were classified according to their drug resistance based on the presence of the pbp mutation, and examined for the presence of the two macrolide-resistance genes, ermB and mefA. Moreover, they were serotyped using type-specific antisera. The mean age of the patients from whom these S. pneumoniae strains were isolated, was 23.4 +/- 30.1 years old, and children aged 15 years old or less accounted for 66% of all the patients. Genotype penicillin-susceptible S. pneumoniae (gPSSP), genotype penicillin-intermediate S. pneumoniae (gPISP) and genotype penicillin-resistant S. pneumoniae (gPRSP) were 22 (7.1%), 131 (42.5%) and 155 (50.3%), respectively. The strains with mefA positive and ermB negative, mefA negative and ermB positive, and mefA positive and ermB positive were 80 (26.0%), 153 (49.7%), and 47 (15.3%), respectively. The MIC90 values of tebipenem (TBPM) and faropenem were 0.06 microg/mL and 0.5 microg/mL, respectively. TBPM showed the high bactericidal activity against gPRSP. In carbapenems, panipenem and biapenem exhibited higher bactericidal activities. Quinolone-resistant S. pneumoniae (QRSP) were isolated from 10 (3.2%). QRSP dominated 5 (7.9%) and 3 (1.5%) among the elderly (over 65 years old) and children, respectively. (As for the serotype, serotypes 6, 19 and 23 were 60 (19.5%), 62 (20.1%), and 44 (14.3%), respectively. Further epidemiologic studies on S. pneumoniae might be required also in the future, including the relationship between the serotype and drug resistance.

[Antibacterial susceptibility surveillance of Haemophilus influenzae isolated from pediatric patients in Gifu and Aichi prefectures (2009-2010)].

We investigated the susceptibility to antibacterial agents of 197 strains of Haemophilus influenzae isolated from pediatric patients at medical facilities in Gifu and Aichi prefectures between 2009 and 2010. Those strains were also examined for the mutations of ftsI coding for penicillin-binding protein 3, presence of bla TEM-1, serotype and beta-lactamase producing ability. Among the 197 strains, the most prevalent serotype was non-typeable (89.8%), followed by serotype b (8.1%), e (1.5%) and f (0.5%). Based on the susceptibility among the 197 strains to antibacterial agents, beta-lactamase nonproducing ampicillin-susceptible H. influenzae (BLNAS) accounted for 27.4%, beta-lactamase nonproducing ampicillin-resistant H. influenzae (BLNAR) for 62.4%, beta-lactamase producing ampicillin-resistant H. influenzae (BLPAR) for 6.1% and beta-lactamase producing amoxicillin/ clavulanic acid-resistant H. influenzae (BLPACR) for 4.1%. According to PCR-based genotyping, the strains were classified into 6 categories: gBLNAS, gLow-BLNAR, gBLNAR, gBLPAR, gBLPACR-I and gBLPACR-II. The incidences of each resistant class were 17.3% for gBLNAS, 6.6% for gLow-BLNAR, 66.0% for gBLNAR, 5.6% for gBLPAR and 4.6% for gBLPACR-II. The combined incidence of gLow-BLNAR and gBLNAR was 72.6%, which was higher than that of BLNAR (62.4%). The MIC90s of antibacterial agents against the 197 strains were as follows; 0.0156 microg/mL for tosufloxacin and garenoxacin, 0.0313 microg/mL for levofloxacin and pazufloxacin, 0.0625 microg/mL for norfloxacin, 0.25 microg/mL for tazobactam/piperacillin (TAZ/PIPC) and ceftriaxone, 0.5 microg/mL for TAZ/PIPC (1:8) and cefditoren, 1 microg/mL for piperacillin, cefteram, cefotaxime, meropenem, tebipenem and minocycline, 2 microg/mL for doripenem, 4 microg/mL for cefcapene, imipenem and azithromycin, 8 microg/mL for sulbactam/ampicillin, clavulanic acid/amoxicillin (1:2, CVA/AMPC) and cefdinir, 16 microg/mL for CVA/AMPC (1:14), flomoxef and clarithromycin, 32 microg/mL for ampicillin. Although there was no rapid increase in the antibacterial resistance, the prevalence of BLNAR was still over 50%. In order to ensure the appropriate chemotherapy, it is important to continue the surveillance of susceptibility among H. influenzae.

[Epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture].

Since antimicrobial resistance in Streptococcus pneumoniae become serious problem, we have conducted the epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture. We have investigated the mutations of penicillin-binding protein (PBP) cording genes, the mutations of macrolide-resistant cording genes, and antimicrobial susceptibility using broth microdilution method, for 345 strains isolated from clinical specimens between May 2006 and July 2006 at 12 clinical facilities of 5 medical area. The ratio of penicillin-susceptible S. pneumoniae (gPSSP), penicillin-intermediate S. pneumoniae (gPISP), and penicillin-resistant S. pneumoniae (gPRSP), which were judged by molecular techniques, were 7.2%, 53.5%, and 39.4%, respectively. Only 1 gPSSP strain was isolated from children under three years old. There have been regional differences of the isolation rate of gPRSP between Gifu/Chuno area (55-60%) and Tono/Hida area (23-32%) in second- or third-medical facilities. The isolation rate of PBP mutation genes, pbp2x, pbp1a and pbp2b, were 92.8%, 52.5% and 53.3%, respectively. The isolation rate of macrolide-resistant cording genes, mefA only, ermB only, and both mefA and ermB, were 30%, 50% and 8%, respectively. The strains of S. pneumoniae with both mefA and ermB mutations, increased from 4% in 2002 to 8% in 2006. The antimicrobial susceptibility of S. pneumoniae to penicillin G (PCG) showed two peaks around 0.03 and 1 microg/mL, and 89% of S. pneumoniae with minimum inhibitory concentration (MIC) value 1 microg/mL was gPRSP. The MIC values of PCG against 69% strains of gPRSP distributed between 0.25 and 1 microg/mL. There have been the decreased tendency for the differences among medical facilities in penicillin resistant strains. Although cefditoren showed the most effective antimicrobial activity in oral cephems tested, there have been the strains with MIC value of over 1 microg/mL. The MIC90 of panipenem was 0.125 microg/mL, which was the best antimicrobial activity in carbapenems. The resistant rates of clarithromycin and azithromycin were 85% and 84%, respectively. The strains with the gene mutation of ermB have showed resistant to clindamycin. The MIC90 of tosufloxacin was 0.25 microg/mL, which was the best antimicrobial activity in quinolones. We have detected 4 levofloxacin highly resistant S. pneumoniae, of which MIC value was over 32 microg/mL. Also, we have encountered the episode of the spread of S. pneumoniae in one family, which was clarified by scientific approach.

[Antibiotic susceptibility of blood-borne Streptococcus pneumoniae and efficacy assessment of respiratory quinolones using Monte Carlo simulation].

We analyzed Streptococcus pneumoniae isolates from the bloodstream between April 2005 and February 2007. We analyzed isolates of 28 strains from medical facilities in Gifu prefecture to determine antibiotic susceptibility, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes. We also assessed the efficacy of respiratory quinolones using Monte Carlo simulation. Garenoxacin (GRNX) and moxifloxacin (MFLX) showed the lowest MIC90 value of 0.125 microg/mL, followed by MIC90 of imipenem (IPM) of 0.25 microg/mL and tosufloxacin (TFLX), MIC90 of meropenem (MEPM) and vancomycin (VCM) of 0.5 microg/mL. Twenty-two strains possessed at least one mutation in PBP-encoding genes pbp1a, pbp2x or pbp2b and seven strains possessed all three mutant alleles. Twenty-two strains possessed either of macrolide resistant genes ermB or mefA, and one strain possessed both. On efficacy assessment, we calculated the probability of target attainment for free-drug area under the curve (fAUC)/MIC ratio (fAUC/MIC). GRNX and MFLX showed a probability of 90% or more at fAUC/MIC of 30 and 125, each considered effective against Gram-positive bacteria and suppression of resistance development, furthermore, GRNX showed a probability of 89.7% at fAUC/MIC of 250.

[Sensitivity surveillance of streptococci isolates for several antibiotics in Gifu prefecture (2005-2007)].

We investigated the susceptibility to antibacterials of streptococci isolated from 8 medical facilities in Gifu prefecture between 2005 and 2007. Strains used in this study include 118 of Group A streptococci, 89 of Group B streptococci, and 58 of group G streptococci. For Group A streptococci, cefteram and imipenem gave the lowest MIC90 at 0.0078 microg/mL, followed by cefditoren and cefcapene at 0.0156 microg/mL and penicillin G, amoxicillin and meropenem at 0.0313 microg/mL. For Group B streptococci, cefteram, cefditoren, cefcapene and imipenem gave the lowest MIC90 at 0.0313 microg/mL, followed by penicillin G and meropenem at 0.0625 microg/mL and amoxicillin at 0.125 microg/mL. For Group G streptococci, cefteram and imipenem gave the lowest MIC90 at 0.0078 microg/mL, followed by penicillin G, cefditoren, cefcapene and meropenem at 0.0156 microg/mL and amoxicillin at 0.0313 microg/mL. With Group A and B streptococci, the susceptibility data obtained in this study were compared with those of strains between 2000 and 2001. As for group A streptococci, the MIC50 and MIC90 of beta-lactam agents were about the same as those of previous study, however the MIC90 of quinolones increased about 2.5-fold and resistant strains were found. As for Group B streptococci, the MIC50 and MIC90 of almost all of the antibacterials were about the same as those of the previous study, however the MIC90 of clarithromycin increased about 10-fold, indicating that the resistant strains are widely spread.

[Sensitivity surveillance of Haemophilus influenzae isolates for several antibiotics in Gifu Prefecture (2006)].

We investigated the susceptibility to antibacterials of 194 strains of Haemophilus influenzae isolated from medical facilities in Gifu prefecture between 2005 and 2006, and compared these results with those of 280 strains of H. influenzae isolated between 1999 and 2000. Additionally, the strains that had been separated between 2005 and 2006 were examined for beta-lactamase (BL) production, the mutation of ftsI gene coding for PBP3, the bla gene coding for TEM type of BL and the serotype. Referring to the CLSI breakpoint, H. influenzae strains were classified into the following categories: (1) beta-lactamase-negative ampicillin-susceptible (BLNAS) strains, which showed BL negative, ampicillin (ABPC) and ampicillin/sulbactam (ABPC/SBT)-MIC < or = microg/ml, (2) beta-lactamase producing ampicillin-resistant (BLPAR) strains, which showed BL producing and ABPC/SBT-MIC < or =2 microg/ml, (3) beta-lactamase-negative ampicillin-resistant (BLNAR) strains, which showed BL negative, ABPC and ABPC/SBT-MIC > or =2 microg/ml, (4) beta-lactamase-producing amoxicillin/clavulanic acid-resistant (BLPACR) strains, which showed BL producing and ABPC/SBT-MIC > or =4 microg/ml. The prevalence of each resistance class were 71.8% for BLNAS, 7.9% for BLPAR, 19.6% for BLNAR and 0.7% for BLPACR in strains isolated between 1999 and 2000. But they were 38.1% for BLNAS, 4.6% for BLPAR, 54.6% for BLNAR and 2.6% for BLPACR in strains isolated between 2005 and 2006, indicating that the percentage of BLNAS and BLPAR decreased and that of BLNAR and BLPACR increased from 1999-2000 to 2005-2006. On the basis of ftsI substitutions and having bla gene, the strains isolated between 2005 and 2006 were classified into the following distribution: 24.2% for gBLNAS, 4.1% for gBLPAR, 10.8% for gLow-BLNAR, 57.7% for gBLNAR, and 3.1% for gBLPACR-II. Ratio of BLNAR belonging to gBLNAR and gLow-BLNAR based on the ftsI substitutions and having bla gene was higher than that based on the susceptibility pattern. The MIC50 and MIC90 for those strains isolated between 2005 and 2006 were as follows; 0.0039, 0.0156 microg/ml for garenoxacin, 0.0078, 0.0156 microg/ml for tosufloxacin and ciprofloxacin, 0.0156, 0.0313 microg/ml for levofloxacin, 0.0313, 0.0625 microg/ml for norfloxacin, 0.0625, 0.25 microg/ml for piperacillin/ tazobactam, 0.0625, 0.5 microg/ml for piperacillin, 0.125, 0.25 microg/ml for ceftriaxone and cefditoren, 0.5, 1 microg/ml for cefteram, chloramphenicol and tetracycline, 0.5, 2 microg/ml for cefotaxime, 2, 8 microg/ml for ampicillin, ampicillin/sulbactam and cefdinir. In comparison with the values for the strains isolated between 1999 and 2000, the MIC50s of beta-lactam for the strains isolated between 2005 and 2006 increased over 4 times.

[The antibacterial activity of fluoroquinolones against gram-negative bacteria isolated from Gifu Prefecture (2005)].

We investigated the susceptibility to 6 fluoroquinolones against 433 strains of Gram-negative bacteria isolated from 6 medical facilities in Gifu prefecture between January and September in 2005, determined by the agar dilution methods in according with the Japan Society of Chemotherapy. We also investigated the correlation between the degree of resistance to fluoroquinolones and the amino acid substitutions in the quinolone resistance-determining region (QRDR). The tested clinical isolates were as follows, Salmonella spp.; 17 strains, Escherichia coli; 112 strains Citrobacter freundii; 35 strains, Enterobacter cloacae; 31 strains, Klebsiella pneumoniae; 73 strains, Proteus spp.; 18 strains, Providencia spp.; 3 strains, Morganella morganii; 14 strains, Serratia marcescens; 27 strains and Pseudomonas aeruginosa; 103 strains. The number of the strains resistant to ciprofloxacin (CPFX) (MIC > or = 6.25 microg/mL) was twenty (E. coli; 14 strains, E. cloacae; I strain, Proteus spp.; 2 strains and P. aeruginosa; 3 strains). Among these strains, 12 strain (E. coli; 11 strains and E. cloacae; 1 strain) were highly resistant to CPFX (MIC > or =25 microg/mL). The E. coli strains highly resistant to CPFX had the multiple amino acid mutations in QRDR of ParC an GyrA. However in other strains, there was no strains possessing multiple mutations in both ParC and GyrA.

[Surveillance on Pseudomonas aeruginosa isolated in Gifu prefecture (2004)].

We analyzed Pseudomonas aeruginosa isolates in Gifu prefecture between September and October 2004. We conducted antimicrobial susceptibility test for 266 strains isolated from 8 medical institutes and 1 clinical laboratory, based on broth microdilution method. The MIC50 and MIC90 of piperacillin, amikacin, imipenem, and ciprofloxacin were 4 and 64, 4 and 8, 1 and 16, 0.25 and 8 microg/mL, respectively. The strains isolated from urine had higher MIC level in comparison with from sputum, which was remarkable in penicillins, cephalosporins and fluoroquinolones. We isolated 7 strains of multi-drug resistant Pseudomonas aeruginosa (MDRP), in which 3 strains showed under 16 microg/mL in MIC against anti-MRSA (methicillin-resistant Staphylococcus aureus) drug arbekacin. Continuous surveillance would be needed for antimicrobial resistance on P. aeruginosa in Gifu prefecture.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibiotics in Gifu prefecture (2004)].

We analyzed Streptococcus pneumoniae isolates in Gifu prefecture between November 2004 and December 2004. We analyzed isolates of 160 strains from 8 medical facilities to determine antibiotic susceptibility, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, and the serotypes of penicillin-resistant S. pneumoniae (PRSP). When referred to the classification in CLSI (formerly NCCLS), the overall incidence of penicillin-susceptible (PSSP), penicillin-intermediate (PISP) and penicillin-resistant (PRSP) were 48 (30.0%), 81 (50.6%) and 31 (19.4%) strains, respectively, and the susceptibility distribution to benzylpenicillin showed triplet peaks. The incidence of PISP and PRSP was higher in the material of throat and nasal cavity, and area of Chuno and Gifu district. The sum of the incidence of PISP and PRSP was slightly higher in inpatient-derived stains than outpatient-derived strains. The incidence that didn't possess mutations in PBP genes and macrolide-resistant genes was 6 (3.75%) and the others 154 strain (96.25%) had abnormal PBP genes or macrolide-resistant genes. The 90% of pneumococcal serotypes of PRSP 31 strains were serotype 6 (14 strains, 45.2%), 19 (7 strains, 22.6%) and 23 (7 strains, 22.6%). The MIC90 of each antibiotics was as follows; 0.1 microg/mL for panipenem, 0.2 microg/mL for imipenem and tosufloxacin, 0.39 microg/mL for meropenem and gatifloxacin, 0.78 microg/mL for amoxicillin, cefteram and cefditoren, 1.56 microg/mL for piperacillin, cefcapene and levofloxacin, 3.13 microg/mL for flomoxef, 6.25 microg/mL for cefdinir and cefotiam, 12.5 microg/mL for norfloxacin and minocycline, 25 microg/mL for cefixime, and 100 microg/mL for clarithromycin.