Analysis of microbiological trends and antibiotic susceptibility in 711 episodes of peritoneal dialysis-related peritonitis / 中华肾脏病杂志

Objective To investigate the microbiological trends and antibiotic susceptibility of peritoneal dialysis(PD)-related peritonitis (PDAP).Methods All patients who developed PDAP between 2004 and 2015 in Renji Hospital,Shanghai Jiao Tong University School of Medicine were enrolled.Demographic data,results of dialysate pathogen culture and drug susceptibility test were recorded.The trend of peritonitis incidence was measured by Poisson regression and the chi-square test or Fisher exact test method was used to compare the composition of causative organisms and their antimicrobial susceptibilities over time.Results During the study period,a total of 711 episodes of PDAP were occurred in 386 patients.The culture positive rate of pathogens rose from 52.0％ in 2004 to 77.0％ in 2015 (P ＜ 0.001).The distribution of causative organisms of the culture positive peritonitis was gram-positive bacteria (270,59.5％),followed by gram-negative bacteria (129,28.4％),polymicrobial(39,8.6％),fungi (15,3.3％) and mycobacteria (1,0.2％).From 2004 to 2015,the incidence of peritonitis decreased from 0.214 to 0.160 episodes/patient·year (P=0.034).The incidence of coagulase-negative staphylococcus peritonitis decreased from 0.049 to 0.027 episodes/patient · year (P=0.025),while others had no significant change;A significant decline was observed in the sensitivity of Gram-positive strains to the first generation cephalosporin and ampicillin/sulbactam in 2010-2015 group compared with those in 2001-2009 group (61.3％ vs 88.2％,P ＜ 0.001;61.7％ vs 85.5％,P=0,001),whereas the sensitivity to vancomycin remained the same.The sensitivity of Gram-negative strains to ceftazidime and amikacin showed no significant change.As for the gram-positive peritonitis treated with cefradine as empirical treatment,compared with those in 2004-2009 group,in 2010-2015group the proportion of patients requiring to change their treatment regime was significantly higher,and the treatment course was longer.Conclusions A gradual decline is observed in the incidence of PDAP and the culture positive rate of pathogens improves.Peritonitis caused by coagulase-negative staphylococcus decreases overtime.The present empirical treatment protocols may need re-evaluation considering the decreased rate of the first generation cephalosporin sensitivity in recent years.

A 5-year Surveillance Study on Antimicrobial Resistance of Acinetobacter baumannii Clinical Isolates from a Tertiary Greek Hospital / 감염과화학요법

BACKGROUND: Acinetobacter baumannii has emerged as a major cause of nosocomial outbreaks. It is particularly associated with nosocomial pneumonia and bloodstream infections in immunocompromised and debilitated patients with serious underlying pathologies. Over the last two decades, a remarkable rise in the rates of multidrug resistance to most antimicrobial agents that are active against A. baumannii has been noted worldwide. We evaluated the rates of antimicrobial resistance and changes in resistance over a 5-year period (2010–2014) in A. baumannii strains isolated from hospitalized patients in a tertiary Greek hospital. MATERIALS AND METHODS: Identification of A. baumannii was performed by standard biochemical methods and the Vitek 2 automated system, which was also used for susceptibility testing against 18 antibiotics: ampicillin/sulbactam, ticarcillin, ticarcillin/clavulanic acid, piperacillin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, gentamicin, amikacin, tobramycin, ciprofloxacin, tetracycline, tigecycline, trimethoprim/sulfamethoxazole, and colistin. Interpretation of susceptibility results was based on the Clinical and Laboratory Standards Institute criteria, except for tigecycline, for which the Food and Drug Administration breakpoints were applied. Multidrug resistance was defined as resistance to ≥3 classes of antimicrobial agents. RESULTS: Overall 914 clinical isolates of A. baumannii were recovered from the intensive care unit (ICU) (n = 493), and medical (n = 252) and surgical (n = 169) wards. Only 4.9% of these isolates were fully susceptible to the antimicrobials tested, while 92.89% of them were multidrug resistant (MDR), i.e., resistant to ≥3 classes of antibiotics. ICU isolates were the most resistant followed by isolates from surgical and medical wards. The most effective antimicrobial agents were, in descending order: colistin, amikacin, trimethoprim/sulfamethoxazole, tigecycline, and tobramycin. Nevertheless, with the exception of colistin, no antibiotic was associated with a susceptibility rate >40% for the entire study period. The most common phenotype showed resistance against ampicillin/sulbactam, cephalosporins, carbapenems, aminoglycosides, ciprofloxacin, and tigecycline. An extremely concerning increase in colistin-resistant isolates (7.9%) was noted in 2014, the most recent study year. CONCLUSION: The vast majority of A. baumannii clinical isolates in our hospital are MDR. The remaining therapeutic options for critically ill patients who suffer from MDR A. baumannii infections are severely limited, with A. baumannii beginning to develop resistance even against colistin. Scrupulous application of infection control practices should be implemented in every hospital unit. Lastly, given the lack of available therapeutic options for MDR A. baumannii infections, well-controlled clinical trials of combinations of existing antibiotics are clearly needed.

Antimicrobial susceptibilities of Listeria monocytogenes human strains isolated from 1970 to 2008 in Brazil / Susceptibilidade antimicrobiana de cepas humanas de Listeria monocytogenes isoladas no período de 1970 a 2008 no Brasil

INTRODUCTION: Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. METHODS: Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC). RESULTS: Among the strains tested, serovar L4b (60.3 percent) was the most prevalent, followed by serovar 1/2a (20.6 percent), 1/2b (13.2 percent) and the more uncommon serovars 1/2c, 3b and 4ab (5.9 percent). All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5 percent) showed resistance to rifampin, and two (3 percent) were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2μg/ml reinforce the need for microbiological surveillance. CONCLUSIONS: The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.

INTRODUÇÃO: Listeria monocytogenes é o agente etiológico da listeriose, doença de origem alimentar que acomete principalmente grávidas, pacientes imunodeprimidos e idosos. O tratamento primário é a associação de ampicilina a um aminoglicosídeo além de outros, em segunda escolha, representados por cloranfenicol, eritromicina, tetraciclina e rifampicina. O presente estudo teve como objetivo analisar o perfil de susceptibilidade aos antimicrobianos de amostras de origem humana isoladas nas últimas quatro décadas. MÉTODOS: Foram selecionadas 68 cepas provenientes de casos clínicos humanos ocorridos em diferentes regiões do país no período de 1970-2008. A susceptibilidade aos antimicrobianos testados foi determinada através dos critérios estabelecidos por Soussy pelo método de Kirby-Bauer e a concentração mínima inibitória realizada através do E-Test. RESULTADOS: A amostragem constituiu-se de 68 cepas, isoladas principalmente de líquido cefalorraquidiano, e hemocultura no período, pertencentes ao Laboratório de Zoonoses Bacterianas/LABZOO/Fiocruz. O sorovar L4b (60,3 por cento) foi o mais prevalente, seguido do sorovar 1/2a (20,6 por cento), 1/2b (13,2 por cento) e aqueles mais raros representados por 1/2c, 3b e 4ab (5,9 por cento). Todas as cepas foram sensíveis à ampicilina, cefalotina, eritromicina, gentamicina, teicoplanina e vancomicina. Apenas uma cepa (1,5 por cento) apresentou resistência à rifampicina, enquanto duas (3 por cento) foram resistentes à associação de sulfametoxazol-trimetoprim. CONCLUSÕES: Apesar de o estudo ter demonstrado uma baixa prevalência de amostras resistentes aos antimicrobianos indicados na terapêutica da listeriose humana, o sistema de monitoramento do perfil de resistência antimicrobiana é de extrema importância para a orientação do tratamento adequado, principalmente nas infecções em pacientes imunocomprometidos.

Antimicrobial Susceptibilities of Ureaplasma urealyticum and Mycoplasma hominis in Pregnant Women / 대한임상미생물학회지

BACKGROUND: Ureaplasma urealyticum and Mycoplasma hominis are associated with an increased risk of pregnancy complications, such as preterm birth and premature membrane rupture. The purpose of this study was to determine the isolation rates and antimicrobial susceptibilities of genital mycoplasma in a sample of pregnant women from Jinju, Korea. METHODS: Vaginal swabs were obtained from 258 pregnant women between 2004 and 2008 and tested for the presence of U. urealyticum and M. hominis at Gyeongsang National University Hospital. The identification and antimicrobial susceptibilities of U. urealyticum and M. hominis were determined with a commercially available kit, the Mycoplasma IST2 Kit (bioMe- rieux, Marcy-l'Etoile, France), and evaluated according to standards set by the Clinical and Laboratory Standards Institute (CLSI). RESULTS: U. urealyticum only was detected in 105 specimens (38.6%), while M. hominis only was detected only in 2 specimens (1.8%). Seven specimens (6.7%) were positive both for U. urealyticum and M. hominis. Susceptibilities of U. urealyticum to azithromycin, erythromycin, clarithromycin, and doxycycline were 75.2%, 82.9%, 88.6%, and 88.6%, respectively, while almost all of the isolates were susceptible to josamycin (99.0%) and pristinamycin (100%). The susceptibility of U. urealyticum to ofloxacin and ciprofloxacin was 56.2% and 15.2%, respectively. CONCLUSION: The rate of isolation of genital mycoplasma in pregnant women was 44.2% in Jinju; most of the mycoplasma were U. urealyticum. U. urealyticum and M. hominis were highly resistant to quinolones, but susceptible to josamycin. Therefore, empirical treatment without prior identification and determination of the antimicrobial susceptibility of genital mycoplasma will fail in many cases.

Healthcare-associated Bacterial Meningitis: A Review of 120 Episodes / 中华医院感染学杂志

OBJECTIVE To characterize clinical feature,frequency of isolation and antimicrobial susceptibility of bacterial pathogens isolated from patients with healthcare-associated bacterial meningitis(HABM).METHODS We review the charts of all patients in whom the diagnosis was based on(national) diagnostic criteria of healthcare-(associated) infections at Huashan Hospital from 1995 through 2004.The pathogens were routinely isolated,(identified) and susceptibilities against antimicrobial agents were determined by Kirby-Bauer methods.RESULTS During the 10-year study period,109 patients were treated for 120 episodes of HABM.Most of patients had a(history) of recent and remote neurosurgery.Fever was present in all patients,while nuchal rigidity and decrease consciousness were present in less than half of all patients.CSF opening(pressure,) white blood cell count and(protein) were elevated with predominance of neutrophils.A total of 120 strains were isolated from CSF specimen,Gram-positive bacteria and Gram-negative bacilli were accounted for 35.8% and(64.2%) of all isolates,respectively.Acinetobacter spp(24.2%),coagulase-negative staphylococci(22.5%),Klebsiella pneumoniae(12.5%),Pseudomonas aeruginosa(10%),Enterobacter cloacae(8.3%) and Staphylococcus aureas(7.5%) were the 6 most frequent isolates and resistance to the first line antibiotics was common among all pathogens isolated.(CONCLUSIONS) The most common risk factor for HABM is neurosurgery.Gram-negative bacilli and staphylococci are important causes of HABM,resistance to the first line antibiotics is common among all pathogens isolated.

Antimicrobial Resistance of Neisseria gonorrhoeae Isolated in Korea / 감염

BACKGROUND: The aim of this study was to monitor trends in antimicrobial susceptibilities of Neisseria gonorrhoeae isolates, in particular, to examine the possibility of increasing prevalence of fluoroquinolone resistance in Korea and the relationship between patterns of mutations involving gyrA and parC genes and the ciprofloxacin resistance level. METHODS: The antimicrobial susceptibilities of 489 gonoccocal isolates which were nationwide collected from patients visiting Health Centers were determined by NCCLS disk diffusion and agar plate dilution methods. PCR and direct DNA sequencing of the amplicons were performed to identify mutations within the quinolone resistance-determining regions of gyrA and parC genes. RESULTS: The proportion of resistance to penicillin, tetracycline, or both remained as high as 94%. The isolates with ciprofloxacin resistance remarkably increased from 1% in 1999 to 5% in 2000 and also resistance to cefoxitine and ceftriaxone were shown to be increased. The strains resistant to spectinomycin was little reported. Four isolates with 16 microgram/mL of MIC for ciprofloxacin all showed the same alternations of Ser-91 to Phe, Asp-95 to Gly in GyrA and Ser-87 to Arg in ParC, but ciprofloxacin-susceptible strains have little amino acid substitution. CONCLUSION: Considering the increasing prevalence of isolates with resistance to ciprofloxacin and ofloxacin, it is likely that the antibiotics such as spectinomycin, or ceftriaxone are recommended as the first-line treatment for gonoccocal infections in Korea. The results from this study suggest that mutation analysis for quinolone resistance-determining regions of gyrA and parC genes are important in epidemiological studies for the spread of ciprofloxacin resistant strains.

Surveillance for antimicrobial resistance of Streptococcus pneumoniae among children attending day care center in Seoul, Korea / 대한임상병리학회지

BACKGROUND: Multidrug-resistant Streptococcus pneumoniae occasionally cause treatment failure in various pneumococcal infection in children. The pneumococcal strains carried at the nosopharynx are frequently found at the time of invasive infection in one individual. We investigated the prevalence of nasopharyngeal carriage of S. pneumoniae and antibiotic susceptibility patterns among children attending day care center and compared the rates of antibiotic resistance of those strains with strains recovered from clinical specimens of patients at a tertiary care hospital. METHODS: Two-hundred nine children from 3 centers distributed at Jong-Ro area of Seoul, Korea were enrolled from May to June, 1998. Swabs were obtained from posterior nasopharynx and cultured onto tryptic soy agar containing 5% sheep blood without and with 10 microgram/mL gentamicin for 24 hours. Clinical isolates included the non-invasive isolates from sputum, ear discharge and sinus aspirate and the invasive isolates from cerebrospinal fluid and blood. Antimicrobial susceptibilities were determined with E-test and agar dilution method. RESULTS: The overall prevalence of nasopharyngeal carriage was 32.5%(68/209). The children >4, 5< OR = years of age have the highest carriage rate(36.7%). But there were no significant differences of prevalence in gender and centers. The prevalences of decreased antibiotic susceptibilities in the nasopharyngeal isolates and clinical isolates were, respectively: penicillin(75% vs 86%, NS); cefotaxime(20% vs 48%, p<0.05); multiresistance(57% vs 86%, p<0.05). Younger the age and female in gender, higher the resistance rate to penicillin. CONCLUSIONS: There was no significant difference in antimicrobial resistance of pneumococci between healthy nosopharyngeal carriages and clinical isolates causing invasive or non-invasive infections. The results acquired from this surveillence would provide a useful guide in an appropriate choice of antimicrobial agents for management of pneumococcal diseases.