Microbiological profile of neonatal septicemia in a pediatric care hospital in Delhi

Septicemia continues to be an important cause of morbidity and mortality in the neonatal units and periodic review of cases to assess any changing trends in the infecting organisms and their antimicrobial susceptibility is important. Over a period of one year (July 2000 to June 2001), 632 samples of blood cultures were submitted to the bacteriology laboratory Microbiology, Lady Hardinge Medical College. These samples were investigated for microbial etiology and the isolates obtained were tested for their susceptibility to the commonly used antibiotics. Twenty per cent (125) cases were culture positive. Gram-negative bacteria were the predominant isolates (62%), commonest being Klebsiella pneumoniae (34%) followed by E. coli (17%), Acinetobacter spp. (9%) and Enterobacter aerogenes (2%). Gram-positive cocci were isolated in 20% cases, of which coagulase negative staphylococcus was the predominant isolate (11%) followed by Enterococcus spp. (5%) and S. aureus (4%). Candida spp. was isolated from 18% of cases. Resistance to commonly used antibiotics was seen in more than 35% of isolates. An alarming observation was the very high incidence of resistance to amoxycillin+clavulanic acid and ceftriaxone (>80%). All isolates showed highest susceptibility to ciprofloxacin.     

Tract microflora in Saudi patients with cholelithiasis

OBJECTIVES: To identify the microflora in the gallbladder of patients undergoing laparoscopic cholecystectomy for gallstones, and the antibiotic susceptibility pattern of the isolates, as well as the usefulness of Gram staining of bile at the time of operation. METHODS: Bile samples were obtained from 112 patients undergoing elective laparoscopic cholecystectomy for gallstones and inoculated directly into aerobic and anaerobic blood culture bottles in the operating theatre. Samples were also collected in sterile universal containers for Gram staining of a centrifuged deposit. Isolates were identified and their in-vitro susceptibilities determined by Kirby Bauer technique. RESULTS: Of 112 bile samples examined, 28 (25%) were culture positive, four of which contained more than one organism. The most common organisms isolated were Escherichia coli 9 (28.1%), Enterococcus faecalis 5 (15.6%) and Pseudomonas aeruginosa 3 (9.4%). In one sample we found Aeromonas hydrophilia and Enterobacter cloacae. No anaerobes were detected but Candida albicans was isolated in one case. In 19 bile samples (67.8%) organisms were identified on Gram stain. Positive bile cultures were found statistically significant (P < 0.05) in patients over the age of 50 (13/32), in patients who developed post-operative fever (6/12) and patients who developed leucocytosis (5/6). CONCLUSION: Age over 50 years was the only significant pre-operative factor associated with positive bile cultures (P < 0.05). In view of the microflora of the gallbladder and the susceptibility pattern of our isolates we would suggest that antibiotic prophylaxis recommended for laparoscopic cholecystectomy for gallstones needs to be reviewed and the role of bacteribilia in the surgical management of cholelithiasis requires further study.     

Pericarditis due to anaerobic bacteria

This review describes the microbiology, diagnosis and management of pericarditis due to anaerobic bacteria. The predominant anaerobes recovered from patients with pericarditis were: gram-negative bacilli (mostly of the Bacteroides fragilis group), anaerobic streptococci, Clostridium spp., Fusobacterium spp., and Bifidobacterium spp. Anaerobic bacteria can be isolated in pericarditis resulting from the following mechanisms: (1) spread from a contiguous focus of infection, either de novo or after surgery or trauma (pleuropulmonary, esophageal fistula or perforation, and odontogenic); (2) spread from a focus of infection within the heart, most commonly from endocarditis; (3) hematogenous infection, and (4) direct inoculation as a result of a penetrating injury or cardiothoracic surgery. No differences were found in the clinical diagnostic features between cases of pericarditis due to anaerobic bacteria and those due to aerobic and facultative bacteria. Anaerobic gram-negative bacilli have increased their resistance to penicillins and other antimicrobials in the last decade. Complete identification and testing for antimicrobial susceptibility and lactamase production are therefore essential for the management of infections caused by these bacteria. Treatment of pericarditis involving anaerobic bacteria includes the use of antibiotic therapy effective against these organisms.     

Genotypic analysis of Acinetobacter bloodstream infection isolates in a Turkish university hospital

Acinetobacter baumannii is a significant pathogen of bloodstream infections in hospital patients that frequently causes single clone outbreaks. We aimed to evaluate the genetic relatedness and antimicrobial susceptibility of Acinetobacter spp. bloodstream isolates, in order to obtain insight into their cross-transmission. This prospective study was conducted at the Erciyes University Hospital. During a 1-y period, all patients with nosocomial BSI caused by Acinetobacter spp. were included in the study. All data with regard to the patients, underlying diseases and risk factors for BSI and the severity of disease were collected. Blood culture isolates of Acinetobacter spp. were identified according to their morphology and biochemical reactions. The antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion test according to the NCCLS; the genetic relatedness of isolates was determined by RAPD-PCR analysis and pulsed-field gel electrophoresis (PFGE). 41 patients acquired a nosocomial bloodstream infection caused by A. baumanii during this period. 88% of these infections (36 of 41) occurred while the patients were treated in the intensive care unit. Nearly 80% of the isolates belonged to 3 genotypes, suggesting cross-transmission in ICU settings where infection control practices are poor. All Acinetobacter isolates were multidrug-resistant and the crude mortality of patients infected with A. baumanii was 80.5%. We concluded that the genetic relatedness of Acinetobacter spp. causing BSI was very high, indicating cross-transmission within the ICU setting. Essential components of an infection control programme to prevent nosocomial transmission of A. baumannii are early detection of colonized patients, followed by strict attention to standard precautions and contact isolation.     

Carriage by the housefly (Musca domestica) of multiple-antibiotic-resistant bacteria that are potentially pathogenic to humans, in hospital and other urban environments in Misurata, Libya

Using standard microbiological procedures, bacteria that are potentially pathogenic to humans were isolated from 150 houseflies collected in the Libyan city of Misurata (50 flies each from the Central Hospital, streets and abattoir). Salmonella spp., Yersinia enterocolitica and Edwardsiella tarda were isolated from flies collected on the streets and in the abattoir but not from those collected in the hospital. Shigella sonnei was detected in just one fly, which was collected in the abattoir. Of the flies collected in the hospital, streets and abattor, 42%, 42% and 32% were positive for Escherichia coli, 70%, 50% and 62% for Klebsiella spp., 2%, 20% and 10% for Aeromonas spp., 96%, 36% and 34% for Pseudomonas spp., 20%, 12% and 16% for Staphylococcus spp., and 24%, 22% and 18% for Streptococcus spp., respectively.When the antibiotic susceptibilities of the fly isolates were investigated, the Enterobacteria isolated from the houseflies collected in the hospital were found to be resistant to significantly more of the commonly used antibiotics that were tested than the Enterobacteria isolated from the flies caught in the streets or abattoir. Whatever the source of the flies from which they were collected, the Pseudomonas isolates frequently showed resistance to multiple antibiotics, with >50% each being resistant to at least 10 antimicrobial agents. Two isolates of Sta. aureus (both from flies collected in the hospital) were resistant to methicillin.The present study supports the belief that the housefly is a potential vector of multiple-antibiotic-resistant, pathogenic bacteria, including methicillin-resistant Sta. aureus, in the hospital environment. Given their mobility, it seems likely that houseflies carry such pathogens from hospitals to surrounding communities, and vice versa.     

北京地区1994-2005年腹泻病原菌的分布及其耐药趋势

目的 监测我院1994-2005年与腹泻有关的肠道致病菌的分布及耐药趋势,为本地区流行病学研究、疫苗制备及临床合理用药提供依据.方法 通过常规大便培养,筛出致病菌后经生化及血清学进一步鉴定到种、群或血清型,并以纸片扩散法测定抗菌药物的敏感性.结果 12年分离到肠道病原菌8426株,患者以男性为主,儿童和青年发病为多,每年7～9月为腹泻发病高峰.病原以志贺菌属居首位(占75.11%),其次是弧菌(占12.70%),再依次为沙门菌属、气单胞菌、致病及侵袭大肠埃希菌分别占6.28%、4.43%及1.25%.6329株志贺菌中,福氏志贺菌占75.62%,其次是宋内菌群(23.98%),痢疾志贺菌及鲍氏志贺菌分别占0.22%及0.01%.12年的变化趋势是,每年肠道病原菌总数在逐渐减少,特别是志贺菌、沙门菌减少明显,而弧菌及气单胞菌相对逐渐增多.各菌属及不同的血清型对抗菌药物的敏感率有差异,福氏志贺菌和气单胞菌属多重耐药较多,而宋内志贺菌和弧菌属对多数抗菌药物敏感.结论 北京地区感染性腹泻的病原种类多,随时间的变迁病原变化明显,耐药性不同,应重视监测.     

Occurrence and antimicrobial susceptibility of Ureaplasma parvum (Ureaplasma urealyticum biovar 1) and Ureaplasma urealyticum (Ureaplasma urealyticum biovar 2) from patients with adverse pregnancy outcomes and normal pregnant women

A recent phylogenetic analysis of Ureaplasma urealyticum resulted in the proposal to divide their 2 biovars into species. We used PCR to compare the distribution of species and the presence of the tet(M) and int-Tn resistance determinants in 63 strains of Ureaplasma spp. isolated from the amniotic fluid of patients with an adverse pregnancy outcome and in 22 strains obtained from the lower genital tract of healthy pregnant women. We also determined the antimicrobial susceptibility of the organisms to erythromycin and tetracycline. U. parvum was the most frequent Ureaplasma species detected in our study. Thus, 50/63 (79.4%) invasive isolates and 17/22 (77.3%) lower genital tract isolates corresponded to U. parvum, whereas 12/63 (19%) invasive isolates and 4/22 (18.2%) non-invasive strains corresponded to U. urealyticum. A mixture of species was found in 2 women. We found no significant differences in the antimicrobial susceptibility of isolates according to species or origin of isolation. Sixty-two strains of Ureaplasma spp. (74.7%) were susceptible to erythromycin, and 21 strains (25.3%) were intermediately susceptible. Sixty-eight isolates (81.9%) were susceptible to tetracycline, 2 strains (2.4%) were intermediate and 13 strains (15.7%) were resistant. DNA sequences related to the tet(M) determinant and the int-Tn gene were found in all tetracycline-resistant isolates.     

Enterobacter bacteremia: clinical features and emergence of antibiotic resistance during therapy

OBJECTIVES: To study the effect of previously administered antibiotics on the antibiotic susceptibility profile of Enterobacter, the factors affecting mortality, and the emergence of antibiotic resistance during therapy for Enterobacter bacteremia. DESIGN: Prospective, observational study of consecutive patients with Enterobacter bacteremia. SETTING: Three university tertiary care centers, one major university-affiliated hospital, and two university-affiliated Veterans Affairs medical centers. PATIENTS: A total of 129 adult patients were studied. MEASUREMENTS: The two main end points were emergence of resistance during antibiotic therapy and death. MAIN RESULTS: Previous administration of third-generation cephalosporins was more likely to be associated with multiresistant Enterobacter isolates in an initial, positive blood culture (22 of 32, 69%) than was administration of antibiotics that did not include a third-generation cephalosporin (14 of 71, 20%; P less than 0.001). Isolation of multiresistant Enterobacter sp. in the initial blood culture was associated with a higher mortality rate (12 of 37, 32%) than was isolation of a more sensitive Enterobacter sp. (14 of 92, 15%; P = 0.03). Emergence of resistance to third-generation cephalosporin therapy (6 of 31, 19%) occurred more often than did emergence of resistance to aminoglycoside (1 of 89, 0.01%; P = 0.001) or other beta-lactam (0 of 50; P = 0.002) therapy. CONCLUSIONS: More judicious use of third-generation cephalosporins may decrease the incidence of nosocomial multiresistant Enterobacter spp., which in turn may result in a lower mortality for Enterobacter bacteremia. When Enterobacter organisms are isolated from blood, it may be prudent to avoid third-generation cephalosporin therapy regardless of in-vitro susceptibility.     

Multidrug resistance Acinetobacter species at the intensive care unit,Aseer Central Hospital,Saudi Arabia:A one year analysis

Objective:To identify and to determine the antimicrobial susceptibility of Acinetobacter baumannii(A.baumannii) clinical isolates from ICU at Aseer Central Hospital.Methods:The study was conducted in the Intensive Care Unit,Aseer Central Hospital,Saudi Arabia over 13 months period(2014-2015).Acinetobacter species(n= 105) were isolated from various clinical samples.Isolates were identified using selected phenotypic criteria and confirmed using the Vitek 2 automated system.This system was used to determine the susceptibilities of 21 antimicrobial agents.Patients,isolates and drug data were analyzed using the SPSS statistical software package to determine some epidemiological and microbiological patterns.Results:Of the 105 stains,A.baumannii accounted for 49(46.67%),A.baumannii complex,19(18.09%),A.baumannii/haemolyticus 32(30.47),Acinetobacter haemolyticus 4(3.81%),Acinetobater lwoffii 1(0.95%) and unidentified Acinetobater species 2(1.3%).Of the 105 Acinetobacter strains,103(98.1%) were found multidrug resistant(MDR).A.baumannii strain were 100% sensitive to colistin and 74.5% to trimethoprim + sulfamethoxazole.The remaining 19 antimicrobial agents revealed low or no sensitivities:amikacin 16.3%; ampicillin 7.7%; ceftazidime 7.3%.Distribution of similar sensitivities was shown by other Acinetobacter species.Mean number of isolates from males and females indicates no statistical variation(P=0.867) whereas age groups showed significant differences(P= 0.008) as it is clear from the high percentage of infected individuals more than 60 years followed by those aged 20 to 29 years old(19.05%).Upper respiratory tract(30.48%),lower respiratory tract(47.65%) and subcutaneous tissue(9.5%) were the main sources of Acinetobacter spp.but mean numbers of isolates from these specimens indicate no discrepancy between specimens(P=0.731).Conclusions:Acinetobacterspecies including A.baumannii were found MDR(98.1%) according to the current Acinetobacter spp.antimicrobial categorization.Approximately half of these strains were A.baumannii.All Acinetobacter species were 100% sensitive to colistin and to some extent to trimethoprim + sulfamethoxazole(74.5%).ICU-acquired pneumonia among patients over 60 years of age who spend prolong times at artificial ventilations made up the majority of the cases.     

Isolation and antibiotic susceptibility of Salmonella and Shigella strains isolated from children in Gaza, Palestine from 1999 to 2006

Background and Aim:  Diarrhea and acute gastroenteritis are among the leading causes of illnesses and death in infants and children throughout the world, especially in developing countries, Globally, Salmonella and Shigella remain the major contributors to acute enteric infections and diarrhea.
Methods:  In the present study, Shigella- and Salmonella -related diarrhea was studied among 3570 children in Gaza, Palestine from January 1999 to September 2006 to determine the prevalence and the antimicrobial susceptibility of the isolates.
Results:  The frequency of isolation was 1.8% (65/3570) for Salmonella spp. and 0.8% (28/3570) for Shigella spp. Shigella flexneri (16/28) was the most frequently isolated Shigella species. Most of the Shigella isolates were resistant to trimethoprim-sulfamethoxazole (89%), ampicillin (79%) and chloramphenicol (46%) and most of the Salmonella isolates showed resistance to ampicillin (62%), trimethoprim-sulfamethoxazole (35%), chloramphenicol (35%) and cephalexin (26%).
Conclusion:  These data reinforce the need for continuous monitoring of microbiological and antimicrobial surveillance and the necessity to regulate the use of antimicrobials. According to the current study, ampicillin, trimethoprim-sulfamethoxazole and chloramphenicol should not be used as empiric treatment of diarrhea in children.     

Assessment of anaerobic blood cultures in pediatric oncology patients

Introduction

The routine use of a single aerobic bottle for blood culture in pediatric patients has become commonplace, as anaerobic bacteria are not frequently involved in clinically significant infections. The aim of this study was to assess the usefulness of routinely performing anaerobic blood cultures in pediatric oncology patients.

Microbiologic study of the bile culture and antimicrobial susceptibility in patients with biliary tract infection

BACKGROUND/AIMS: Bacterial infection of biliary tract may cause severe inflammatory response or sepsis. An immediate bile culture and appropriate antibiotic administration are important to control the biliary tract infection. The objective of the study was to identify organisms in bile and the features of antibiotic susceptibility in patients with biliary tract infection. METHODS: We retrospectively reviewed the clinical records of 212 patients whose bile had been cultured for variable biliary tract diseases at Inje University Ilsan Paik Hospital from Jan. 2000 to Feb. 2007. Bile samples were obtained from percutaneous transhepatic biliary drainage (PTBD, n=89), percutaneous transhepatic gallbladder drainage (PTGBD, n=14) or endoscopic naso-biliary drainage (ENBD, n=49). RESULTS: The overall positive rate of bile culture was 71.7% (152 cases). The organisms cultured were Escherichia coli (25.0%), Enterococcus spp. (13.4%), Klebsiella spp. (11.1%), Pseudomonas spp. (11.1%), and coagulase-negative Staphylococcus (9.7%) in decreasing order. Effective antibiotics for Gram-negative organisms were amoxicillin/clavulanic acid, amikacin, imipenem, and piperacillin/tazobactam in order of effectiveness. Of the cultured blood samples from 160 patients, fifty (31.2%) showed positive bacterial growth. The organisms isolated from blood were similar to those found in the bile. CONCLUSIONS: A broad spectrum penicillin/beta-lactamase inhibitor is a recommendable antimicrobial for empirical treatment for biliary tract infection. However, Gram-positive bacteria such as Enterococcus spp. or methicillin-resistant Staphylococcus aureus are emerging as causative microorganisms. If these organisms are isolated, antimicrobial drugs should be replaced by narrower-spectrum antimicrobials.     

Antimicrobial susceptibility pattern of blood isolates from a teaching hospital in north India

Bloodstream infections are associated with significant patient morbidity and mortality worldwide. In this study, we examined antimicrobial susceptibility patterns by reviewing the data on 5,704 blood samples that were collected from patients with fever/sepsis admitted to Government Medical College and Hospital, Chandigarh, India, over a period of 1 year from August 2003 to July 2004. Among the 567 qualifying samples, Pseudomonas aeruginosa (19.75%), Escherichia coli (15.17%), Klebsiella pneumoniae (14.99%), and Salmonella enterica serovar Typhi (12.87%) were the most frequently isolated Gram-negative bacteria other than Citrobacter, Acinetobacter, Proteus, and Enterobacter spp. collectively accounting for 80.96% of the isolates. Staphylococus aureus (13.86%) and Enterococcus feacalis (2.35%) were most frequently isolated Gram-positive bacteria other than other Streptococcus and Staphylococcus spp. collectively accounting for 18% of the isolates. Among the antibiotics used for susceptibility testing of Gram-negative isolates, amikacin showed higher activity (76.61%) against Enterobacteriaceae and ciprofloxacin (65.17%) against non-fermenters. However, cefoperazone + sulbactum showed the highest activity (82.66%) among all Gram-negative isolates. For Gram-positive isolates, vancomycin (100%), ciprofloxacin (89.74%) showed the highest activity against Staphylococcus spp. Combinations of antibiotics are often prescribed as emperic therapy for bacteremia, especially for Gram-negative pathogens. Hence the antibiotic susceptibility patterns of blood isolates reported here may be a useful guide for physicians initiating emperic therapy with antibiotics.     

Prevalence of Campylobacter jejuni and enteric bacterial pathogens among hospitalized HIV infected versus non-HIV infected patients with diarrhoea in southern India

A prevalence study on Campylobacter jejuni and other enteric bacterial pathogens was carried out in 200 HIV infected and 200 non-HIV infected subjects with diarrhoeal symptoms at an AIDS Hospital in southern India. Diarrhoeal specimens were inoculated onto standard culture media as well as onto Columbia and Campylobacter blood agar media for C. jejuni isolation. All the C. jejuni isolates were tested for antimicrobial susceptibility using Kirby-Bauer's method. A significant difference in recovery rates was observed between the 2 groups in relation to C. jejuni (p < or = 0.02; 95% CI 5.5 (1-10) and Shigella spp. (p < or = 0.02; 95% CI 6.5 (1-12). 21 isolates of Shigella spp., 16 C. jejuni, 5 Salmonella typhi, 3 Arcobacter spp., 3 Yersinia enterocolitica, and 2 Aeromonas hydrophila were recovered from the HIV infected cases. All the C. jejuni isolates were sensitive to ciprofloxacin whereas 1 strain was resistant to nalidixic acid. Interestingly, all the 29 Shigella spp. (21 from HIV and 8 from non-HIV cases) were resistant to erythromycin and most were resistant to many other antibiotics used. Our observations underline the need for epidemiological investigations to screen C. jejuni and Shigella spp. in HIV infected subjects with diarrhoea and analyse their antibiograms periodically to minimize disease burden in HIV/AIDS.     

2009年山东大学附属省立医院细菌耐药性监测及分析

目的了解山东大学附属省立医院2009年临床分离菌株分布及耐药谱。方法收集山东大学附属省立医院2009年首次非重复分离株1 821株,细菌鉴定采用VITEK鉴定系统,药敏试验采用纸片扩散法,数据采用WHONET 5.4软件进行统计分析。结果大肠埃希菌和肺炎克雷伯菌对碳青霉烯类药物最敏感;柠檬酸杆菌属、沙雷菌属对碳青霉烯类药物敏感率较高,肠杆菌属和柠檬酸杆菌属对头孢西丁的耐药率分别为98.6%和85.7%,而沙雷菌属耐药率仅为30%;铜绿假单胞菌对哌拉西林/他唑巴坦、头孢吡肟、哌拉西林、头孢他啶、美罗培南、亚胺培南和头孢哌酮/舒巴坦较敏感,对其他药物敏感率均〈70%;鲍曼不动杆菌对亚胺培南、美罗培南敏感率为82.3%、73.2%,对头孢哌酮/舒巴坦耐药率为11.6%,对其他药物耐药率在15.0%~67.8%;葡萄球菌对万古霉素和利奈唑胺100%敏感,耐甲氧西林金黄色葡萄球菌和耐甲氧西林凝固酶阴性葡萄球菌检出率分别为45.0%和86.8%;屎肠球菌和粪肠球菌对万古霉素和利奈唑胺最敏感。结论肠杆菌科细菌对碳青霉烯类药物仍最为敏感,但不发酵糖菌对其耐药率升高;葡萄球菌属中均未发现耐万古霉素菌株。     

Resistance trends of Acinetobacter spp. in Latin America and characterization of international dissemination of multi-drug resistant strains: five-year report of the SENTRY Antimicrobial Surveillance Program.

OBJECTIVES: To analyze the antimicrobial susceptibility of Acinetobacter spp. isolates collected from Latin American medical centers as part of the SENTRY Antimicrobial Surveillance Program and also to evaluate the dissemination of multi-drug resistant Acinetobacter spp. strains in the region. METHODS: A total of 826 isolates of Acinetobacter spp. from multiple infection sites were collected from January 1997 to December 2001 in ten medical centers and susceptibility tested to >25 selected agents by broth microdilution. Multi-drug resistant Acinetobacter spp. isolates were molecular typed. RESULTS: Resistance rates to carbapenems varied significantly among countries. A continued annual increase occurred in the Argentinean medical centers. In contrast, carbapenem resistance was rare in Chilean centers, and decreased significantly in the Brazilian institutions. Acinetobacter spp. isolates recovered from lower respiratory tract and bloodstream infections were associated with lower antimicrobial susceptibility rates. Resistance rates to imipenem were higher among isolates collected from intensive care units (13.5%) than among isolates from other units. A major ribogroup pattern (521-1) was detected among eight Acinetobacter spp. strains isolated from three distinct Latin American countries. CONCLUSIONS: This study found that antimicrobial resistance is still a major issue among Acinetobacter spp. isolates collected from some Latin American countries. The dissemination of a major bacterial cluster in different regions reinforces the importance of longitudinal surveillance programs, such as SENTRY, as valuable tools for monitoring antimicrobial susceptibility rates and guiding local interventions.     

Characterization of methicillin-resistant Staphylococcus aureus isolates from patients with persistent or recurrent bacteremia

BACKGROUND:

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with considerable morbidity and mortality, especially with persistent (PB) or recurrent bacteremia (RB).

OBJECTIVE:

To determine the frequency of PB and RB in patients with MRSA BSI, and to characterize the isolates from these patients.

METHODS:

Surveillance for MRSA BSI was performed for one year in 13 Canadian hospitals. PB was defined as a positive blood culture that persisted for ≥7 days; RB was defined as the recurrence of a positive blood culture ≥14 days following a negative culture. Isolates were typed using pulsed-field gel electrophoresis (PFGE). Vancomycin susceptibility was determined using Etest.

RESULTS:

A total of 183 patients with MRSA BSI were identified; 14 (7.7%) had PB and five (2.7%) had RB. Ten (5.5%) patients were known to have infective endocarditis, and five of these patients had PB or RB. Initial and subsequent MRSA isolates from patients with PB and RB had the same PFGE type. There were no significant differences in the distribution of PFGE types in patients with PB or RB (37% CMRSA-2/USA100; 37% CMRSA-10/USA300) compared with that in other patients (56% CMRSA-2/USA100; 32% CMRSA-10/USA300). All isolates were susceptible to vancomycin, but patients with PB or RB were more likely to have initial isolates with vancomycin minimum inhibitory concentration = 2.0 μg/mL (26% versus 10%; P=0.06).

CONCLUSIONS:

Persistent or recurrent MRSA bacteremia occurred in 10.4% of patients with MRSA BSIs. Initial isolates from patients with persistent or recurrent MRSA BSIs were more likely to exhibit reduced susceptibility to vancomcyin, but were not associated with any genotype.     

Bacterial and fungal bloodstream isolates from 796 hematopoietic stem cell transplant recipients between 1991 and 2000

To examine shifts in the etiology, incidence, evolution, susceptibility, and patient mortality of bacterial and fungal bloodstream isolates (BSIs) from hematopoietic stem cell transplantation (HSCT) recipients, we reviewed the BSIs of 796 patients who underwent an HSCT in our institution during a 10-year period. Four hundred eighty-nine episodes of bacterial and fungal BSI were detected in 330 patients (41%). Three hundred ten isolates (63%) were gram-positive bacteria, 142 (29%) were gram-negative, and 18 and 19 isolates were different species of anaerobic organism and Candida spp. (both 4%). Coagulase-negative staphylococci (CoNS), with 210 isolates, were the organism most frequently isolated in each year of study and during the three phases of immune recovery after HSCT. The ratio of gram-positive to gram-negative has declined from 3.3 (1991–1992) to 1.8 (1999–2000). Crude mortality occurred in 47 cases of 489 BSI episodes (10%). Mortality according to groups was gram-negative, 7%; gram-positive, 9%; and anaerobic bacteria, 11%. Candida spp. was the group that accounted for the highest crude mortality, with 42%. Gram-positive microorganisms were isolated more often than gram-negative organisms, but the trend is reversing. CoNS were the leading pathogen during the 10 years of study and during the three phases of immune recovery after HSCT. Crude mortality of HSCT patients with BSI was low except for infections caused by Candida spp.Disclosures. Conflict of interest: none. Redundant publications: no substantial overlapping with previous papers. This study was presented at the 43rd ICAAC (K-1370).     

Serotype, Shiga toxin (Stx) type, and antimicrobial resistance of Stx-producing Escherichia coli isolated from humans in Shizuoka Prefecture, Japan (2003-2007)

The serotype, Shiga toxin (Stx) type, and antimicrobial resistance patterns of 138 Stx-producing Escherichia coli (STEC) strains isolated from humans between 2003 and 2007 in Shizuoka Prefecture, Japan were characterized. The predominant O serogroups of the STEC isolates were O157, O26, and O111. Antimicrobial susceptibility testing of the STEC isolates showed that 31 of the 138 isolates (22.5%) were resistant to antibiotics. Compared to the results reported in the previous studies, a higher rate of STEC O157 isolates were susceptible to all the antimicrobial agents used in this study. However, antimicrobial susceptibility data from this study showed that antimicrobial resistance patterns have increased by 6 compared to the survey performed by Masuda et al. between 1987 and 2002 (Jpn. J. Food Microbiol., 21, 44-51, 2004). This indicates that STEC isolates have evolved to show a variety of antimicrobial resistance patterns. It is important to consider the population of isolates showing decreased susceptibility to clinically relevant drugs such as ciprofloxacin (CPFX) and fosfomycin (FOM). All the 3 STEC isolates resistant to nalidixic acid showed low susceptibility to CPFX (MIC, 0.25-0.5 μg/ml). In addition, a decreased susceptibility to FOM was clearly observed in the E. coli O26 isolates. Our findings also showed that 1 STEC O26 strain could possibly be a chromosomal AmpC β-lactamase hyperproducer. These results suggest that antimicrobial therapy may be less effective in patients with non-O157 STEC infections than in those with STEC O157 infections.     

2005年至2007年中国CHINET脑脊液的分离菌及其耐药性

目的 了解2005年至2007年中国CHINET监测网脑脊液分离菌的分布及其耐药性.方法 对CHINET监测网2005年1月至2007年12月所有脑脊液标本按常规方法进行分离、培养、鉴定.按统一方案用Kirby-Bauer纸片扩散法进行抗菌药物敏感试验.结果 2005年至2007年脑脊液标本获分离菌941株,其中革兰阳性菌588株.占62.5%;革兰阴性菌349株,占37.1%;真菌4株,占0.4%.革兰阳性菌所占比例由2005年的59.9%增至2007年的64.6%,革兰阴性菌所占比例由2005年的39.6%降至2007年的35.4%.最常见的分离菌依次分别为凝固酶阴性葡萄球菌、不动杆菌属、肠球菌属、铜绿假单胞菌、金黄色葡萄球菌、大肠埃希菌、克雷伯菌属、肠杆菌属、肺炎链球菌、链球菌属和其他假单胞菌.葡萄球菌属和肠球菌属中未发现万古霉素耐药株,肺炎链球菌对青霉素的耐药率为42.9%.肠杆菌科细菌对碳青霉烯类高度敏感,不动杆菌属和铜绿假单胞菌对碳青霉烯类耐药率为24.1%～29.3%.结论 2005年至2007年脑脊液分离菌中革兰阳性菌多于革兰阴性菌,脑脊液分离株对常用抗菌药物耐药明显.