Pathogen Antimicrobial Susceptibility Research Articles

Bacteriological Profile of Patients With Stroke-Associated Pneumonia and Antimicrobial Susceptibility of Pathogens: A Cross-Sectional Study.

Stroke-associated pneumonia (SAP) is the aftermath of aspiration of oropharyngeal secretions or stomach content. Mechanical ventilation and lowered immunity and consciousness facilitate the etiopathogenesis of SAP. Antibiotic prophylaxis and repeated culture and sensitivity testing dampen the drug susceptibility patterns of the pathogens. We accomplished this study to determine the bacteriological profile of patients with SAP and the antimicrobial susceptibility patterns of the pathogenic bacteria. This cross-sectional study was executed from August 2022 to May 2024 at Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar, India. We included adult patients who endured treatment inthe neurosurgery intensive care unit (ICU) throughout the study period due to a stroke and developed pneumonia within 48 hours of admission. The endotracheal tube (ET) aspirate and bronchoalveolar lavage (BAL) fluid specimens collected from the eligible participants were analyzed. Enriched and selective media such as 5% sheep blood agar, chocolate agar, and MacConkey agar were used to culture pathogenic bacteria. The VITEK 2 system was used to identify isolates and assess antimicrobial susceptibility testing (AST). The pathogenic bacteria and their antimicrobial susceptibility patterns were gauged. We leveraged R software (version 4.4.1) for data analysis. Two hundred forty bacterial isolates were found in the 181 eligible patients. Forty-eight (26.52%) participants were females. The median age of the study population was 64.50 (58.74-70.24) years. Fifty-nine (32.60%) participants had two different isolates in their culture reports. We found the following non-fermenters: Acinetobacter baumannii (55, 22.92%), Pseudomonas aeruginosa (31, 12.92%), Burkholderia cepacia (6, 2.50%), and Elizabethkingia meningoseptica (4, 1.67%). Klebsiella pneumoniae (88, 36.67%) and Escherichia coli (15, 6.25%) were the most commonly noticed Enterobacterales. Other Enterobacterales were Proteus mirabilis (9, 3.75%), Serratia marcescens (8, 3.33%), Klebsiella oxytoca (3, 1.25%), Enterobacter aerogenes (1, 0.42%), Providentia stuartii (1, 0.42%), and Enterobacter cloacae complex (5, 2.08%). Staphylococcus aureus (14, 5.83%) was the only gram-positive cocci in our study population. The sensitivity of A. baumannii was maximum for minocycline. P. aeruginosa was highly sensitive to imipenem and completely resistant to tigecycline. Minocycline was the only effective drug against E. meningoseptica. Similarly, the Enterobacterales had the greatest sensitivity for tigecycline. All 14 specimens of S.aureus were sensitive to both vancomycin and linezolid. They were responsive to tigecycline as well. The most common pathogenic bacteria in our study were K. pneumoniae, A. baumannii, P. aeruginosa, E. coli, and S. aureus. Enterobacterales were highly sensitive to tigecycline. A. baumannii and E. meningoseptica had maximum sensitivity for minocycline. All isolates of S. aureus were sensitive to both vancomycin and linezolid. We warrant further research with a larger sample size to investigate the bacteriological profile among other critically ill patients and their AST findings.

Distribution Patterns and Antibiotic Resistance Profiles of Bacterial Pathogens Among Patients with Wound Infections in the Jiaxing Region from 2021 to 2023.

To systematically assess the distribution and antimicrobial susceptibility of pathogens in wound infections, and analyze risk factors associated with multidrug resistance (MDR). Retrospectively analyzing Jiaxing-region medical records between January 2021 and December 2023, we identified a cohort of 461 wound infection patients. Cultures were grown on various agars, with bacteria identified via Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. The antimicrobial susceptibility of the organisms were conducted by VITEK 2 system, Kirby-Bauer disk diffusion method and Epsilometer test. Statistical Package for the Social Sciences (SPSS) version 22 was used for statistical analysis. Multivariable logistic regression models were developed to pinpoint risk factors for multidrug-resistant organism (MDRO) infections and predict occurrences. From 461 patients, 549 bacterial pathogens were isolated, predominantly consisting of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Enterobacter cloacae, and Enterococcus faecalis. Vancomycin, linezolid, and tigecycline maintained their efficacy against Staphylococcus aureus and Enterococcus species, while Pseudomonas aeruginosa demonstrated sensitivity to aminoglycosides. Conversely, Escherichia coli exhibited high amoxicillin resistance (85.4%). More than half of the isolates were resistant to levofloxacin, ceftriaxone, cotrimoxazole, and gentamicin, with Acinetobacter baumannii strains showing considerable resistance (65.8-68.4%) to advanced cephalosporins and carbapenems. Within this group, 58 MDROs were detected, primarily originating from Burn Plastic Surgery, Emergency, and Intensive Care Unit (ICU) departments. Multivariate logistic regression identified hyperglycemia, hypoalbuminemia, surgery, extended hospitalization, and exposure to multiple antibiotic classes as independent risk factors for MDRO wound infections. Based on these findings, a predictive model for MDRO occurrence in wounds was constructed, which had a sensitivity of 0.627, specificity of 0.933, and an Area Under the Curve (AUC) of 0.838. Staphylococcus aureus and Pseudomonas aeruginosa dominated in wound infections with differential antibiotic resistance. Independent risk factors included hyperglycemia, hypoalbuminemia, surgery, extended hospitalization, and polyantibiotic use. We urge prioritizing culture, susceptibility tests, and personalized antibiotic strategies to address MDRO risks and improve wound infection management specificity and efficacy.

Culture-confirmed neonatal bloodstream infections and meningitis in South Africa, 2014–19: a cross-sectional study

SummaryBackgroundFew population-level estimates of invasive neonatal infections have been reported from sub-Saharan Africa. We estimated the national incidence risk, aetiology, and pathogen antimicrobial susceptibility for culture-confirmed neonatal bloodstream infections and meningitis in South Africa.MethodsWe conducted a cross-sectional study of neonates (<28 days of life) admitted to neonatal or paediatric wards of 256 public sector health facilities in South Africa during 2014–19. Diagnostic pathology records from Jan 1, 2014, to Dec 31, 2019, were extracted from a national pathology data warehouse. A case was defined as a neonate with at least one positive blood or cerebrospinal fluid culture during a 14-day period. Incidence risk was calculated using annual numbers of registered livebirths. Among the causative pathogens identified, we calculated the proportion of cases attributed to each of them, as well as the rates of antibiotic susceptibility of Gram-positive and Gram-negative bacteria.FindingsAmong 43 438 records of positive cultures, there were 37 631 incident cases of neonatal infection with at least one pathogen isolated. The overall incidence risk of culture-confirmed infections was 6·0 per 1000 livebirths (95% CI 6·0–6·1). The incidence risk of late-onset sepsis (days 3–27 of life) was 4·9 per 1000 livebirths (4·9–5·0) and that of early-onset sepsis (days 0–2 of life) was 1·1 per 1000 livebirths (1·1–1·1); risk ratio 4·4 (95% CI 4·3–4·5). The cause of infection differed by syndrome, timing of infection onset, facility, and province, although Klebsiella pneumoniae (26%), Acinetobacter baumannii (13%), and Staphylococcus aureus (12%) were the dominant pathogens overall. Gram-negative bacteria had declining susceptibility to most antibiotics over the study period.InterpretationWe found a high incidence risk of late-onset sepsis with provincial variations, predominance of K pneumoniae, and declining antibiotic susceptibility among Gram-negative bacteria. This national surveillance in an upper-middle-income country provides a baseline burden of neonatal infections against which the impact of future clinical and public health interventions can be measured.FundingBill & Melinda Gates Foundation.

Nationwide surveillance of bacterial pathogens isolated from children conducted by the surveillance committee of Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2017: General overview of pathogenic antimicrobial susceptibility

A nationwide surveillance of the antimicrobial susceptibility of pediatric patients to bacterial pathogens was conducted by Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in Japan in 2017. The isolates were collected from 18 medical facilities between March 2017 and May 2018 by the three societies. Antimicrobial susceptibility testing was conducted at the central laboratory (Infection Control Research Center, Kitasato University, Tokyo) according to the methods recommended by the Clinical Laboratory Standards Institute. Susceptibility testing was evaluated in 926 strains (331 Streptococcus pneumoniae, 360 Haemophilus influenzae, 216 Moraxella catarrhalis, 5 Streptococcus agalactiae, and 14 Escherichia coli). The ratio of penicillin-resistant S.pneumoniae was 0% based on CLSI M100-ED29 criteria. However, three meropenem or tosufloxacin resistant S.pneumoniae isolates were obtained. Among H.influenzae, 13.1% of them were found to be β-lactamase-producing ampicillin resistant strains, while 20.8% were β-lactamase non-producing ampicillin-resistant strains. No capsular type b strains were detected. In M.catarrhalis, 99.5% of the isolates were β-lactamase-producing strains. All S.agalactiae and E.coli strains were isolated from sterile body sites (blood or cerebrospinal fluid). The ratio of penicillin-resistant S.agalactiae was 0%, while that of extended spectrum β-lactamase-producing E.coli was 14.3%.

Outpatient Parenteral Antibiotic Therapy (OPAT) with Peripherally Inserted Central Catheter in Patients with Periprosthetic Joint Infection.

A key factor in the successful treatment of periprosthetic joint infection is the consistent antimicrobial therapy. Depending on the pathogen antimicrobial susceptibility, intravenous (i. v.) antibiotics may not be switched to oral medication at patient discharge, without risking a treatment failure. The implementation of an outpatient i. v. therapy using peripherally inserted central catheters (PICCs) allows for early discharge with continuation of adequate antimicrobial therapy. We prospectively evaluated the systematic use of PICC in 11 patients with periprosthetic joint infection. Inclusion criterion was the detection of a pathogen that cannot be optimally treated with oral antibiotics according to the current treatment concept (Trampuz et al.). A total of 12 PICCs in 11 patients were analysed. An error or mechanical nerve irritation was not observed. The occurrence of a catheter-related bloodstream infection (CRBSI) was not recorded. None of our patients had PICC-associated infections, thrombophlebitis or thrombosis. One patient stopped therapy due to a lack of compliance. Ten patients successfully completed their treatment. At a mean follow-up of 29 months, successful infection eradication as measured by the Delphi criteria was achieved in 100%. Although the number of patients included in the study was small, our short-term results suggest a good applicability of PICCs in the outpatient i. v. antimicrobial therapy for treatment of periprosthetic joint infection. Catheter-associated complications could not be observed in our collective. The successful infection control in all cases despite proven difficult-to-treat infection is promising.

Monitoring of Frequency and Antimicrobial Susceptibility of Pathogens on the Hands of Healthcare Workers in a Tertiary Hospital.

To monitor microbes, focusing on drug resistance, on the hands of the personnel of four departments of a tertiary hospital (ICU, neonatal unit, internal medicine ward and surgical ward) and explore differences between departments, professions and genders. Hand sampling from 125 healthcare employees was conducted followed by isolation, identification and antibiotic resistance profiling of different microbial species. Staphylococcus spp was the most prevalent microbe (76/125, 60.8%), followed by different Gram-negative pathogens (45.6%). ICU employees had a significant probability to have Gram-negative contamination [OR 3.627 (95% CI 1.220-10.782)], independently of gender or profession. Staphylococcus spp presence was associated with working in the internal medicine ward [OR 6.976 (95% CI 1.767-25.540)] and the surgical ward [OR 5.795 (95% CI 1.586-21.178)]. Staphylococcus spp was more prevalent in males vs. females (81.3% vs. 54.9%, p=0.008) and in medical vs. nursing personnel (76.9% vs. 54.8, p=0.019). In the majority of Gram-negative isolates (56.1%), at least one multi-drug resistant (MDR) or extensively drug resistant (XDR) strain was isolated. A statistically significant higher prevalence of XDR Gram-negative microbes was found on the hands of nursing personnel (22.2% vs. 2.3% for medical doctors, p=0.014). Only 2 methicillin resistant Staphylococcus Aureus (MRSA) out of the 12 Staphylococcus aureus positive samples were identified. Employees in the ICU are more prone to Gram-negative and not to Gram-positive hand contamination. MDR and XDR pathogens are prevalent, and are associated with nursing profession.

Predictors of disease complications and treatment outcome among patients with chronic suppurative otitis media attending a tertiary hospital, Mwanza Tanzania.

BackgroundChronic suppurative otitis media (CSOM) is a major health problem in developing countries causing hearing loss and life threatening complications. Early and effective treatment based on the knowledge of causative micro-organisms and predictors of outcome are crucial in preventing these associated complications. This study was conducted to determine the predictors of CSOM complications, treatment outcome and antimicrobial susceptibility of pathogens, thus providing essential evidence to formulate a policy for management of CSOM.MethodsThis was a prospective hospital based cross sectional study involving 301 patients attending Ear Nose and Throat (ENT) clinics at Bugando Medical Centre (BMC) between October 2013 and March 2014. A standardized data collection tool was used to collect demographics and clinical characteristics of patients with CSOM. Ear swabs were collected using sterile cotton swabs and transported to the laboratory for culture and antibiotic susceptibility testing.ResultsOut of 301 patients with CSOM; 187 (62.1 %) had positive aerobic culture within 48 h of incubation. Disease complications and poor treatment outcome were observed in 114 (37.8 %, 95 % CI; 32.2–43.3) and 46 (15.3 %, 95 % CI; 11.2–19.3) respectively. On multivariate logistic regression analysis factors found independently to predict both disease complications and poor treatment outcome were otalgia, being infected by multi drug resistant bacteria and being HIV positive. Prolonged illness duration before seeking medical attention was also found to be associated with disease complications (OR 1.029, 95 % CI 1.007–1.05, p = 0.01). A total of 116 (61 %) of gram negative bacteria were isolated. Of 34 Staphylococcus aureus, 14 (41 %) were found to be methicillin resistant Staphylococcus aureus (MRSA) while of 116 g negative enteric bacteria, 49 (42 %) were extended spectrum beta lactamases producers (ESBL).ConclusionsFindings of this study suggest that positive HIV status, infection due to multidrug resistant pathogens and otalgia are significantly associated with disease complications and poor treatment outcome. Of great importance this study confirms that prolonged illness duration without seeking medical attention significantly predicts disease complications. Urgent preventive measures and laboratory guided early treatment are necessary to reduce complications associated with CSOM.

Surveillance of Antimicrobial Resistance in Bacteria-Associated with Central Line-Associated Bloodstream Infections, as Reported by California Hospitals From 2011 to 2014

• The California Department of Public Health (CDPH) Healthcare-Associated Infections (HAI) Program oversees the prevention, surveillance, and reporting of HAIs in California acute care hospitals. • Approximately 400 California hospitals report HAI data to CDPH via the CDC’s National Healthcare Safety Network (NHSN). When reporting central lineassociated bloodstream infections (CLABSIs), hospitals are required to indicate the associated pathogen(s) and specific antimicrobial susceptibility test results. • Pathogen antimicrobial susceptibility data from CLABSIs reported by California hospitals to NHSN during 2011-2014 were analyzed to estimate the prevalence of antimicrobial resistance among bacterial pathogens in California hospitals. Additionally, data were assessed for trends over time.

Urinary tract infections caused by Pseudomonas aeruginosa among children in Southern Poland: Virulence factors and antibiotic resistance

The aim of this study was to analyze antibiotic resistance and virulence patterns in Pseudomonas aeruginosa (PAR) isolates from urinary tract infections among children in Southern Poland. This study comprised consecutive, non-repetitive PAR isolates sent from two collaborative laboratories. The study group consisted of children aged up to 17 years from Southern Poland with culture-proven PAR UTIs. Relevant information about patients with UTIs, such as age, sex, and type of infection (polymicrobial or monomicrobial), was collected. Isolates were screened for major virulence factors found in uropathogenic PAR strains. Multidrug-resistant (MDR) strains were defined as strains not susceptible to one antimicrobial in at least three different antimicrobial classes. Extensively drug resistant (XDR) strains were defined as strains susceptible to no more than two antimicrobial classes. The total prevalence of PAR UTIs was 2.1%, and in children <5 years of age it was 3.0%. A total of 26 isolates was tested: 21 from outpatients and five from inpatients. Most infections (80.8%) occurred in children ≤ 4 years of age. The most prevalent virulence gene was exoY (96.2%). The prevalence of other effector proteins was 88.5% for exoT, 92.3% for exoS, and 19.2% for exoU. The gene for LasB was present in 80.8% of isolates; the gene for AprA in 61.5%; the gene for PilA in 19.2%; and the gene for PilB was not detected. The PAR isolates were generally susceptible to beta-lactam and aminoglycoside antimicrobials. All isolates were also susceptible to colistin. A large proportion of isolates were resistant to carbapenems and fluoroquinolones (Fig. 1). No significant differences were found in antimicrobial resistance between males and females or inpatients and outpatients (p > 0.05 for all tested antimicrobials), or in antimicrobial resistance between younger (≤ 5 years old, n = 21) and older (> 5 years old, n = 5) children (p > 0.05 for all tested antimicrobials). Two isolates were classified as XDR and none as MDR. The EDTA test yielded one MBL-positive isolate (3.8%), from a 17-year-old patient in home care. No isolates with genes for the KPC, IMP, or VIM were identified. As data on UTIs in children with Pseudomonas etiology are scarce, this paper provides useful information for clinicians and allows for comparison between Poland and other countries. Our findings have important implications for clinicians treating UTIs empirically, because the success of empiric treatment is based on knowledge of pathogen antimicrobial susceptibility patterns.

Central line-associated bloodstream infections in Australian intensive care units: Time-trends in infection rates, etiology, and antimicrobial resistance using a comprehensive Victorian surveillance program, 2009-2013

The epidemiology of central line-associated bloodstream infections (CLABSI) in Australian intensive care units (ICUs) has not previously been reported. We sought to describe time-trends in CLABSI rates, infections by ICU peer-groups, etiology, and antimicrobial susceptibility of pathogens in a large cohort of Australian ICUs for the period January 1, 2009-December 31, 2013. Using National Healthcare Safety Network methods, CLABSI surveillance in adult patients was performed by hospitals participating in the Victorian Healthcare Associated Infection Surveillance System (n = 29). Hospitals were grouped by location, sector, and teaching status. Overall, 384 CLABSI events were reported over 303,968 central venous catheter (CVC)-days, corresponding to a rate of 1.26/1,000 CVC-days (95% confidence interval, 1.14-1.40). Every 1-year increase was associated with a 26% reduction in CLABSI risk (risk ratio, 0.74, 95% confidence interval, 0.69-0.80; P < .001). The most frequently identified pathogens were Enterococcus spp (26.3%), followed by Candida spp (15.4%) and Staphylococcus aureus (13.3%). CLABSI due to Enterococcus spp, S aureus, and coagulase-negative Staphylococcus spp displayed significant reductions over time. Internationally accepted surveillance methods have been employed in Australia, demonstrating CLABSI rates comparable to medical/surgical ICUs in the United States and a reduction in pathogen-specific infections over a 5-year period.

Antimicrobial susceptibility of organisms causing community-acquired urinary tract infections in Gauteng Province, South Africa

Patients with community-acquired urinary tract infections (UTIs) frequently present to healthcare facilities in South Africa (SA). To provide information on UTI aetiology and antimicrobial susceptibility of pathogens. We recruited women with UTI-related symptoms, who tested positive for ≥2 urine dipstick criteria (proteinuria, blood, leucocytes or nitrites) at 1 public and 5 private primary healthcare facilities in 2011. Demographic and clinical data were recorded and mid-stream urine (MSU) specimens were cultured. UTI pathogens were Gram-stained and identified to species level. Etest-based antimicrobial susceptibility testing was performed for amoxicillin/clavulanic acid, cefixime, cefuroxime, ciprofloxacin, fosfomycin, levofloxacin, nitrofurantoin, norfloxacin and trimethoprim/sulphamethoxazole. Of the 460 women recruited, 425 MSU samples were processed and 204 UTI pathogens were identified in 201 samples. Most pathogens were Gram-negative bacilli (GNB) (182; 89.2%) and 22 (10.8%) were Gram-positive cocci (GPC). Escherichia coli was the most frequent GNB (160; 79.6%), while Enterococcus faecalis was the predominant GPC (8; 4.0%). The UTI pathogens had similar susceptibility profiles for fosfomycin (95.5%; 95% confidence interval (CI) 92.6 - 98.4), the 3 fluoroquinolones (94.1%; 95% CI 90.8 - 97.4), nitrofurantoin (91.7%; 95% CI 87.8 - 95.6), cefuroxime (90.1%; 95% CI 86.0 - 94.3) and cefixime (88.2%; 95% CI 83.7 - 92.6). UTI pathogens were less susceptible to amoxicillin/clavulanic acid (82.8%; 95% CI 77.5 - 88.0) when compared with fluoroquinolones and fosfomycin. Trimethoprim/ sulphamethoxazole was the least efficacious antimicrobial agent (44.3% susceptible; 95% CI 37.4 - 51.2). This study provides relevant data for the empirical treatment of community-acquired UTIs in SA.

Prevalence and Antimicrobial Susceptibility of Pathogens in Urinary Tract Infections

This study was done to assess the bacterial profile and antibiotic susceptibility pattern of urinary tract infections (UTIs) pathogens. For proper identification of causative microbial agents, mid stream urine samples from 459 patients with clinical symptoms suspected to be UTI were collected, cultured and subjected to appropriate biochemical tests. These samples were collected from Teaching Laboratories Center in Baghdad during the study period (1 st January 2009 - 1 st July 2009). The antimicrobial sensitivity test was carried out by disc diffusion technique using Muller- Hinton agar. 100 urine samples were cultured positive with a colony count equal or more than 10 5 /ml while 359 cases were excluded as they were culture negative or exhibited mixed infections. Overall males to females ratio was 1:3.2. The most prevalence isolates were Escherichia coli with frequency rate of 50% followed by Enterobacter spp.(12%). Whereas, Klebsiella spp., Pseudomonas aeruginosa and Enterococcus faecalis showed frequency rate of 9% for each. Howevere, Proteus spp., Staphylococcus aureus, Staphylococcus epidermidis and Acinetobacter spp.showed frequency rate less than 5%. The majority of isolates were sensitive to imipenem (96%) followed by amikacin(89%) and nitrofurantion(69%) whereas, high level resistance was seen to cotrimoxazole, ampicillin and trimethoprim followed by cefoxitin, nalidixic acid, gentamicin and cefotaxime in decreasing order of frequency.

Bloodstream Infections in Children with Cancer between 2005 and 2008 in a Single Center

Purpose : In children on anticancer chemotherapy, bloodstream infections (BSIs) are a major cause of morbidity and mortality. We investigated febrile episodes and bloodstream infections in pediatric cancer patients to guide proper selection of empiric antibiotics for febrile pediatric hemato-oncologic patients. Methods : All febrile episodes treated in the division of hematology-oncology, the department of pediatrics, Hanyang University Hospital, between July 2005 and June 2008 were reviewed. Episodes with and without bloodstream infections were compared. Results : Forty cases (18.9%, 25 patients) of BSI occurred in 212 febrile episodes (63 patients). Thirty-seven cases (23.6%, 22 patients) of BSI occurred in 157 febrile episodes with neutropenia (54 patients). Microorganisms identified in BSI corresponded to 23 gram-positive bacteria (51.2%), 20 gram-negative bacteria (44.5%), and 2 fungi (4.4%). Rates of BSI between those who had received umbilical cord blood transplantation and those who had received transplantation from other source were significantly different (55.0% vs. 7.7%, P =0.001). No differences in mortality rate were observed among organisms in BSI patients. For febrile episodes the rate of BSI was higher among those with Chemoport than those with Hickman catheter (P =0.029) and gram-positive pathogens were more likely to be associated with Chemoport (P =0.001). Conclusion : The study showed the rate of BSI, distribution of pathogens with regard to neutropenia, transplantation, central venous catheters, and antimicrobial susceptibility of pathogens in order to help guide in the choice of optimal empiric antibiotics in pediatric febrile neutropenic hemato-oncologic patients.

Antimicrobial susceptibility of pathogens isolated from more than 10 000 patients with infectious respiratory diseases: a 25-year longitudinal study

The Study Group on Antimicrobial Susceptibility of Pathogens Isolated from Respiratory Infections was established in 1981 in Japan to elucidate trends in such susceptibilities in patients with infectious respiratory diseases; the Group has conducted nationwide research in collaboration with 21 medical institutions. Examination of more than 10,000 patients by 2005 allowed a summary of study findings. Streptococcus pneumoniae started to become resistant to penicillin G in the 1990s, and the isolation rate of penicillin-intermediate and penicillin-resistant S. pneumoniae (PISP + PRSP) reached almost 60% in 2001. The proportion of PRSP also increased, reaching 19.4%. Thereafter, the rate of PISP + PRSP decreased somewhat to the mid-30% range. Macrolide resistance was also observed; in 2005, the prevalence of strains highly susceptible to erythromycin with MICs <or= 0.06 microg/ml had decreased to 15.5%, whereas the proportion of highly resistant strains with MICs >or= 128 microg/ml exceeded 40%. Among Staphylococcus aureus isolates, the proportion of methicillin-resistant S. aureus (MRSA) strains began to increase rapidly in 1986 and constituted around 60% of all S. aureus strains identified in 1990 and in the following years. In 1993, the prevalence of ampicillin-resistant isolates of Haemophilus influenzae had increased remarkably, presumably related to the outbreak of beta-lactamase-negative ampicillin-resistant (BLNAR) H. influenzae strains, and the proportion of these strains among the isolates surpassed 30% in 2002 and thereafter. For Klebsiella pneumoniae, the antimicrobial activity of first- to fourth-generation cephems improved with each generation. The MIC distribution patterns of Pseudomonas aeruginosa shifted towards higher MICs when compared with the MICs for other pathogens. Broad patterns with no distinct peaks reflected the difficulty in treating P. aeruginosa infection. Regarding Moraxella catarrhalis, beta-lactamase-producing strains already constituted a majority of the isolates in 1990, and the proportion of strains highly susceptible to ampicillin, with MICs <or= 0.06 microg/ml, was less than 10% at that time.

Bloodstream infections in haematology: Risks and new challenges for prevention

Bloodstream infections are an important cause of morbidity and mortality in the haematology population, and may contribute to delayed administration of chemotherapy, increased length of hospitalisation, and increased healthcare expenditure. For gram-positive, gram-negative, anaerobic and fungal infections, specific risk factors are recognised. Unique host and environmental factors contributing to pathogenesis are acknowledged in this population. Trends in spectrum and antimicrobial susceptibility of pathogens are examined, and potential contributing factors are discussed. These include the widespread use of empiric antimicrobial therapy, increasingly intensive chemotherapeutic regimens, frequent use of central venous catheters, and local infection control practices. In addition, the risks and benefits of prophylaxis, and spectrum of endemic flora are identified as relevant factors within individual centres. Finally, challenges are presented regarding prevention, early detection, surveillance and prophylaxis. To reduce the rate and impact of bloodstream infections multifaceted and customised strategies are required within individual haematology units.

The Importance and Future of Antimicrobial Surveillance Studies

Surveillance studies provide important information that allows for the identification of trends in pathogen incidence and antimicrobial resistance, including identification of emerging pathogens at national and global levels. Routine surveillance is critical for creating and refining approaches to controlling antimicrobial resistance and for guiding clinician decisions regarding appropriate treatment. The traditional approach has been to monitor pathogen antimicrobial susceptibility; numerous large studies have been performed, and their designs have evolved over time. Longitudinal studies are particularly useful because important information can be obtained by comparing data over time. Another approach to surveillance, that of monitoring antimicrobial use, can help to identify trends in dosing, to prevent the development of resistance. Several studies have incorporated this approach into their methods, and both large and small studies have attempted to correlate antimicrobial use data with antimicrobial resistance data. Overall, care must be taken to coordinate programs for optimal utilization of resources, to avoid duplication of effort.

Prevalence and antimicrobial susceptibility of pathogens in uncomplicated cystitis in Europe. The ECO·SENS study

The ECO.SENS study investigated the prevalence and antimicrobial susceptibility of pathogens causing community-acquired acute uncomplicated urinary tract infections (UTIs) in 4734 women aged 18-65 years presenting with symptoms of acute UTI, at 252 community healthcare centres in 16 countries in Europe plus Canada. Resistance in Escherichia coli occurred most frequently to ampicillin (30%) and sulphonamides (29%), followed by trimethoprim (15%), trimethoprim/sulphamethoxazole (14%) and nalidixic acid (5%) but was low to co-amoxiclav, mecillinam, cefadroxil, nitrofurantoin, fosfomycin, gentamicin and ciprofloxacin, all at<3%. Consumption of antibiotics in 1997 varied more than 4-fold within Europe and from 9 to 37 DDD/1000 inhabitants/day, the consumption being highest in Southern Europe. The consumption of broad-spectrum penicillins correlated with resistance to ampicillin and there was a clear correlation between quinolone consumption and resistance to ciprofloxacin and nalidixic acid. The 4-fold difference in antibiotic consumption within Europe and the correlation to resistance emphasises the importance of controlling antibiotic usage.

Age-related trends in pathogen frequency and antimicrobial susceptibility of bloodstream isolates in North America: SENTRY Antimicrobial Surveillance Program, 1997–2000

We report age-related trends in pathogen frequency and antimicrobial susceptibility from 25,745 bloodstream infections (BSI) due to bacterial pathogens reported from medical centres participating in the North American SENTRY Antimicrobial Surveillance Program between January 1997 and September 2000. Staphylococcus aureus, Escherichia coli and coagulase-negative staphylococci (CoNS) were the most common pathogens, together accounting for 55% of all BSI pathogens during this time period. Among nosocomial BSI, CoNS were the most frequently isolated pathogens in infants less than 1 year of age, but S. aureus increased in frequency with increasing age. Among community-onset BSI pathogens, Streptococcus pneumoniae was the most frequently reported pathogen causing BSI in patients aged 1-5, S. aureus among those aged 6-64, and E. coli predominated at the extremes of age (less than 1 year and > or = 65 years of age). Among key organism: antimicrobial agent combinations evaluated, oxacillin resistance in S. aureus increased with increasing age; conversely, oxacillin resistance among CoNS was highest among children 5 years of age or younger. Penicillin resistance among S. pneumoniae BSI was highest in children younger than 5 years, while vancomycin resistance among Enterococcus spp. predominated among nosocomial BSI in patients over 50 years of age. Important age-related differences exist in species distribution and antimicrobial susceptibility of pathogens causing BSI. This information should be helpful for clinicians as they consider empirical antimicrobial therapy for patients with suspected BSI across the age continuum.

Chairman's Introduction - The Importance of Good Quality Surveillance Data Today

The Alexander Project is a continuing, international, multicenter, longitudinal study of the antimicrobial susceptibility of pathogens commonly associated with community-acquired lower respiratory tract infections (LRTI). The study began in 1992 to provide high-quality surveillance data, comparable between regions and through time. As antimicrobial resistance becomes more prevalent, reliable surveillance data are required for clinical decision-making. Accurate current susceptibility data are required to predict clinical success through the determination of pharmacodynamic breakpoints. The Alexander Project provides the information required for clinicians to improve the likelihood of microbiological and clinical cure in the antibiotic treatment of LRTI.

Prevalence of potential respiratory disease bacteria in children in Ethiopia. Antimicrobial susceptibility of the pathogens and use of antibiotics among the children

Acute respiratory infections are primary causes of morbidity and mortality in children in developing countries. This project was designed to investigatc antimicrobial susceptibility of respiratory tract pathogens isolated from children in rural and city areas, and to contribute to the rational choice of antibiotics for respiratory tract infections in children in Ethiopia. Nasopharynx and throat cultures were taken from all children under five years of age in three study areas representing different levels of contact with health care and accessibility to modern drugs, such as antibiotics. In all, 1126 children were cultured. Huemophilus influence and Streptococcus pneumonicie were both found in 85–90% of the children, and beta‐haemolytic streptococci group A in 12%. The level of antimicrobial resistance was low. None of the 954 strains of H. irfluence were beta‐lactamase producers. Pneumococci were susceptible to penicillin. The use of antibiotics was also low; 11 of 1126 children had antibiotics on the day of culture or the day before. The choice of antibiotics was not limited by resistance, and emphasis could be put on low cost, minimizing adverse drug reactions and ecological impact.