Trends In Antimicrobial Susceptibility Research Articles

Antimicrobial susceptibility trends for urinary isolates in the veteran population

Guidance on empiric treatment for urinary tract infections (UTIs) is lacking for the male population which comprises much of the Veteran population in the United States. This study evaluated susceptibility trends in antimicrobials used for treatment of UTIs in the inpatient and outpatient Veteran population nationwide. Urine culture data was retrospectively obtained from Corporate Data Warehouse. All urine cultures from Veteran Health Administration patients 18 years of age or older who were treated at any VA health care center in the years 2009 and 2018 were eligible. Antibiograms were constructed for bacterial isolate susceptibility. In 2009 and 2018 isolates from 54,788 and 58,983 Veterans were analyzed, respectively. Escherichia coli was the most common bacteria isolated. For ceftriaxone, E coli susceptibilities were relatively high but trended downward from 2009 to 2018. Common urinary pathogen susceptibilities remained low for fluoroquinolones and trimethoprim-sulfamethoxazole. Empiric therapy for Veterans with UTIs should be based on local susceptibility patterns as previously recommended first-line agents have fallen out of favor due to increasing resistance rates. Both inpatient and outpatient stewardship is needed to ensure appropriate treatment, as viable treatment options for UTIs are becoming increasingly limited.

Utilization of cumulative antibiograms for public health surveillance: Trends in Escherichia coli and Klebsiella pneumoniae susceptibility, Massachusetts, 2008-2018.

Antimicrobial resistance is an urgent public health threat. Identifying trends in antimicrobial susceptibility can inform public health policy at the state and local levels. To determine the ability of statewide antibiogram aggregation for public health surveillance to identify changes in antimicrobial resistance trends. Facility-level trend analysis. Crude and adjusted trend analyses of the susceptibility of Escherichia coli and Klebsiella pneumoniae to particular antibiotics, as reported by aggregated antibiograms, were examined from 2008 through 2018. Multivariable regression analyses via generalized linear mixed models were used to examine associations between hospital characteristics and trends of E. coli and K. pneumoniae susceptibility to ciprofloxacin and ceftriaxone. E. coli and K. pneumoniae showed inverse trends in drug susceptibility over time. K. pneumoniae susceptibility to fluoroquinolones increased by 5% between 2008 and 2018 (P < .05). In contrast, E. coli susceptibility declined during the same period to ceftriaxone (6%), gentamicin (4%), and fluoroquinolones (4%) (P < .05). When compared to Boston hospitals, E. coli isolates from hospitals in other regions had a >4% higher proportion of susceptibility to ciprofloxacin and a >3% higher proportion of susceptibility to ceftriaxone (P < .05). Isolates of K. pneumoniae had higher susceptibility to ciprofloxacin (>3%) and ceftriaxone (>1.5%) in all regions when compared to Boston hospitals (P < .05). Cumulative antibiograms can be used to monitor antimicrobial resistance, to discern regional and facility differences, and to detect changes in trends. Furthermore, because the number of years that hospitals contributed reports to the state-level aggregate had no significant influence on susceptibility trends, other states should not be discouraged by incomplete hospital compliance.

Trends in Antimicrobial Susceptibility of Escherichia coli Isolates in a Taiwanese Child Cohort with Urinary Tract Infections between 2004 and 2018.

The aim of this study was to investigate the annual incidence of Escherichia coli isolates in urinary tract infections (UTIs) and the antimicrobial resistance of the third-generation cephalosporin (3GCs) to E. coli, including the factors associated with the resistance in hospitalized children in Taiwan. A large electronic database of medical records combining hospital admission and microbiological data during 2004–2018 was used to study childhood UTIs in Taiwan. Annual incidence rate ratios (IRR) of E. coli in children with UTIs and its resistant rate to the 3GCs and other antibiotics were estimated by linear Poisson regression. Factors associated with E. coli resistance to 3GCs were assessed through multivariable logistic regression analysis. E. coli UTIs occurred in 10,756 unique individuals among 41,879 hospitalized children, with 92.58% being community associated based on urine culture results reported within four days after the hospitalization. The overall IRR E. coli UTI was 1.01 (95% confidence interval (CI) 0.99–1.02) in community-associated (CA) and 0.96 (0.90–1.02) in healthcare-associated infections. The trend in 3GCs against E. coli increased (IRR 1.18, 95% CI 1.13–1.24) over time in CA-UTIs. Complex chronic disease (adjusted odds ratio (aOR), 2.04; 95% CI, 1.47–2.83) and antibiotics therapy ≤ 3 months prior (aOR, 1.49; 95% CI, 1.15–1.94) were associated with increased risk of 3GCs resistance to E. coli. The study results suggested little or no change in the trend of E. coli UTIs in Taiwanese youths over the past 15 years. Nevertheless, the increase in 3GCs-resistant E. coli was substantial. Interventions for children with complex chronic comorbidities and prior antibiotic treatment could be effective in reducing the incidence of 3GCs-resistant E. coli in CA-UTIs in this region and more generally.

ISOLATION AND ANTIMICROBIAL SUSCEPTIBILITIES OF NONTUBERCULOUS MYCOBACTERIA FROM WILDLIFE IN JAPAN.

Nontuberculous mycobacteria (NTM) are opportunistic pathogens of humans and animals and are transmitted among the environment, wildlife, livestock, and humans. The aim of this study was to investigate the rate of isolation and antimicrobial susceptibility of NTM in wildlife. In total, 178 samples of feces (n=131) and tissues (n=47) were collected from 11 wildlife species in Gifu Prefecture and Mie Prefecture, Japan, between June 2016 and October 2018. We isolated NTM from 15.3% (20/ 131) of fecal samples using Ogawa medium, and isolates were identified by sequencing the rpoB and hsp65 genes. The rpoB sequences were compared with those from other strains of human and environmental origin. The NTM isolates were obtained from sika deer (Cervus nippon), wild boar (Sus scrofa), Japanese monkey (Macaca fuscata), raccoon dog (Nyctereutes procyonoides), masked palm civet (Paguma larvata), and Japanese weasel (Mustela itatsi) and were classified as rapidly growing mycobacteria (RGM) and slowly growing mycobacteria (SGM). The 12 RGM identified were Mycolicibacterium peregrinum (n=5), Mycolicibacterium fortuitum (n=3), Mycolicibacterium septicum (n=3), and Mycolicibacterium thermoresistibile (n=1), and the eight SGM were Mycobacterium paraense (n=4), Mycolicibacter arupensis (n=2), Mycolicibacter virginiensis (n=1), and Mycobacterium nebraskense (n=1). The NTM from wildlife showed ≥99% similarity with strains from different sources including humans. The RGM were susceptible to the antimicrobial agents tested except for M. fortuitum, which was resistant to azithromycin and clarithromycin. The SGM showed multiple drug resistance qualities but were susceptible to amikacin, clarithromycin, and rifabutin. These results indicate that wildlife may be reservoir hosts of NTM in Japan. The presence of antimicrobial-resistant NTM in wildlife suggests that the trends of NTM antimicrobial susceptibility in wildlife should be monitored.

Distribution and antimicrobial resistance profiles of bacterial species in stray cats, hospital-admitted cats, and veterinary staff in South Korea

BackgroundAntimicrobial resistance is becoming increasingly important in both human and veterinary medicine. According to the One Health concept, an important step is to monitor the resistance patterns of pathogenic bacteria. In this study, the antimicrobial susceptibility patterns and trends of bacteria isolated from stray cats, hospital-admitted cats, and veterinary staff in South Korea between 2017 and 2018 were investigated.ResultsThe minimum inhibitory concentrations of different antibiotics for Staphylococcus spp., Enterobacteriaceae, and Enterococcus spp. were determined to establish representatives of different antibiotic classes relevant for treatment or surveillance. For Coagulase-positive and Coagulase-negative Staphylococci, resistance to fluoroquinolones was below 13%, but resistance to ampicillin and penicillin was high (20–88%). A total of 9.5, 12.1, and 40.3% of staphylococcal isolates from stray cats, hospital-admitted cats, and veterinary staff, respectively, were confirmed to be mecA positive. For Enterobacteriaceae, resistance to carbapenems, fluoroquinolones, and 3rd generation cephalosporins was low (0–11.1%). The Enterococcus spp. isolates showed no resistance to vancomycin. The antimicrobial resistance rates of the Staphylococcus spp. and Enterobacteriaceae isolates from stray cats were usually lower than those of isolates from hospital-admitted cats and veterinary staff, but the Enterococcus spp. isolates revealed the opposite. Thus, the antimicrobial resistance varied across bacterial species according to the source from which they were isolated.ConclusionsResistance to critically important compounds were low. However, the presence of antimicrobial resistance in cat isolates is of both public health and animal health concern.

Antimicrobial Susceptibility Trends among Pathogens Isolated from Blood: A 6-Year Retrospective Study from a Tertiary Care Hospital in East Sikkim, India.

Background Bloodstream infections (BSIs) are one of the frequent nosocomial infections among hospitalized patients. To understand the local epidemiology and evolving antimicrobial drug resistance of blood-borne pathogens, we analyzed the distribution and antibiotic sensitivity profile of organisms causing BSI in our hospital-based study. Materials and Methods We reviewed retrospective data of laboratory-confirmed BSIs, from January 2013 to December 2018. Causative organisms and their antibiotic susceptibility profile of primary and secondary BSI reports were determined from BacT/Alert and Vitek systems findings (bioMérieux). A 6-year multidrug resistance indexing was done to document the resistance pattern of the commonly isolated organisms. Results A total of 1,340 (10.2%) BSIs were reported from 13,091 blood cultures. Organisms were frequently isolated from the younger population (≤20 years), especially from ages < 1 year (20.8% of total BSIs). Majority of pathogens were bacterial (97.1%) whereas 2.9% were fungal in origin. Monomicrobial growth was recorded in over 98% of BSIs. Gram-positive and gram-negative bacteria isolated were 518 (39.8%) and 783 (60.2%), respectively. Commonly isolated organisms were coagulase-negative Staphylococci (29.4%), Escherichia coli (19.8%), Klebsiella species (13.5%), Salmonella species (9.4%), and Staphylococcus aureus (7.5%). Multidrug-resistance index was observed highest in Acinetobacter species followed by Pseudomonas aeruginosa and S. aureus . Conclusion Overall, there has been a gradual decline in the reporting of BSI. However, infections by gram-negative bacilli and multidrug-resistant organisms remain persistently high. Ages < 20 years were the vulnerable group, with infants < 1 year contributing to the maximum number of BSI cases caused by both bacteria and fungi. Therefore, additional methods are required to study the origin and causation of these infections, particularly among vulnerable patients.

Klebsiella pneumoniae presents antimicrobial drug resistance for β-lactam through the ESBL/PBP signaling pathway.

Overuse and misuse of antibiotics leads to antibiotic resistance which has become a significant public health concern. Klebsiella pneumoniae is the most common pathogenic bacteria underlying nosocomial infections due to the expression of virulence factors and occurrence of antibiotic resistance. Evidence indicates that β-lactamase is involved in the antibiotic resistance of Klebsiella pneumoniae to β-lactam antibiotics. The aim of the present study was to investigate the association between the molecular biological mechanisms of antibiotic resistance of Klebsiella pneumoniae and extended-spectrum β-lactamase (ESBL). In order to assess temporal trends in prevalence and antimicrobial susceptibility, Klebsiella pneumoniae bacteria were isolated and the ESBL expression level was analyzed. Susceptibility tests were performed using automated systems. The β-lactam-resistance in Klebsiella pneumoniae was assessed by the β-lactam agar screen plate and respective MIC values were evaluated using E-test strips. The confirmatory disk diffusion methods were applied for phenotypic identification of the ESBL production of Klebsiella pneumoniae. The results showed that Klebsiella pneumoniae bacteria exhibited higher ESBL production after treatment with β-lactam compared to the control. The ESBL gene expression was upregulated in Klebsiella pneumoniae after treatment with β-lactam. Results identified that penicillin-binding proteins (PBPs) were associated with the growth and resistance to β-lactams. Zinc finger nuclease markedly inhibited the antibiotic resistance of Klebsiella pneumoniae to β-lactam. PBP knockdown abolished the inhibitory effects of zinc finger nuclease on the growth of Klebsiella pneumoniae induced by β-lactam antibiotic treatment. In conclusion, these results suggest that the resistance of Klebsiella pneumoniae bacteria to antimicrobial drugs is through the ESBL signaling pathway, which indicates that ESBL may be a potential target for abolishing resistance to β-lactam.

181. Antimicrobial Susceptibility Trends and Risk Factors for Antibiotic Resistance in Pseudomonas aeruginosa Bacteremia: A 10-Year Experience at a Korean Tertiary Hospital

BackgroundBacteremia due to Pseudomonas aeruginosa is associated with high mortality and inappropriate initial antimicrobial therapy leads to worse outcomes. We aimed to analyze clinical characteristics of P. aeruginosa bacteremia and risk factors for antibiotic resistance and investigate their antimicrobial susceptibility trends.MethodsWe retrospectively reviewed the medical records of patients with P. aeruginosa bacteremia admitted to a tertiary hospital between January 2009 and March 2019.ResultsA total of 242 patients were identified and the median age was 70 years [interquartile range (IQR) 57.6–75.4]. Hepatobiliary tract (28.5%) was most common primary site of infection, followed by respiratory tract (20.2%) and urinary tract (15.7%). Out of 197 (81.4%) patients treated with susceptible antibiotics and the median duration of active antibiotic therapy was 10 days (IQR 4–15.5). The percentages of susceptible P. aeruginosa to amikacin, aztreonam, cefepime, ceftazidime, ciprofloxacin, colistin, gentamicin, imipenem, meropenem, piperacillin–tazobactam, and ticarcillin-clavulanate were 90.1%, 57.9%, 77.3%, 74.8%, 74.4%, 99.2%, 91.3%, 76.0%, 76.0%, 69.4%, and 51.2%. There were 24.8% carbapenem-resistant P. aeruginosa (CRPA), 36.4% multidrug-resistant P. aeruginosa (MDRPA), and 15.3% extensively drug-resistant P. aeruginosa (XDRPA). Susceptible P. aeruginosa to gentamycin and ticarcillin-clavulanate were significantly decreased in 2014–2019 than that in 2009–2013 (both; P < 0.001). Resistance rates to carbapenems and fluoroquinolones tended to increase over time. CRPA, MDRPA, and XDRPA were significantly associated with delayed active therapy (>48 h) (all; P < 0.001). Independent risk factors for CRPA were urinary tract infection (adjusted odds ratio [aOR], 3.4; 95% confidence interval [CI], 1.5–7.8), underlying hematologic malignancy (aOR, 3.0; 95% CI, 1.1–8.3) and cerebrovascular accident (aOR, 2.6; 95% CI, 1.1–5.9), hospital-acquired infection (aOR, 2.5; 95% CI, 1.0–6.1), and co-colonization with multidrug-resistant organisms (aOR, 2.2; 95% CI, 1.1–4.4).ConclusionThe identification of risk factors for antibiotic resistance and analysis of antibiotics susceptibility are useful for early initiation of appropriate antibiotics in patients with P. aeruginosa bacteremia.Disclosures All authors: No reported disclosures.

Trends in antimicrobial susceptibility of blood culture-positive typhoid fever over half a decade in adults attending a tertiary care teaching hospital in South India

Background: Typhoid fever is a public health concern in developing countries. Developed countries have also been influenced due to tourism. The drugs used for treating typhoid fever can and have been rendered unusable due to resistance. Monitoring and updating the Salmonella antibiogram is needed to prevent therapeutic failures. This study confirms to the same goal.Methods: This study was conducted retrospectively in a tertiary care hospital in North Kerala with data collected from 2013 to 2017. Years were categorized into four quarters to analyze seasonality. Positive blood culture samples of adults, identified to be Salmonella typhi or paratyphi were subjected to antimicrobial sensitivity.Results: 37 Salmonella isolates were included. July-September quarter was found to have maximum incidence of typhoid fever followed by April-June quarter. All isolates were 100% sensitive to ceftriaxone, chloramphenicol, and amoxicillin-clavulanic acid. Sensitivity lacked for nalidixic acid (48.65%), ciprofloxacin (48.65%) and levofloxacin (70.27%). Sensitivity to ampicillin and cotrimoxazole was 86.49% and 91.89%. Azithromycin efficacy was good overall (94.59%) with resistant isolates emerging in final year of this study.Conclusions: Monsoon is most conducive for typhoid fever occurrence followed by summer. This study confirms utility of ceftriaxone and futility of quinolones and fluoroquinolones in typhoid fever treatment. Azithromycin has started showing emergence of resistance. Ampicillin and cotrimoxazole cannot be relied upon due to variability in sensitivity patterns. Chloramphenicol showed full efficacy throughout the study period which is encouraging. Amoxicillin-clavulinic acid, surprisingly was 100% effective throughout study period. However, no contemporary data is available for comparison.

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The Incidence, Aetiology and Antimicrobial Susceptibility of Central Line-Associated Bloodstream Infections in Intensive Care Unit Patients at a Private Tertiary Care Hospital in Mumbai, India

AbstractBackground: There is a need to generate accurate data on temporal trends in incidence rates, aetiology and antimicrobial susceptibility of central line-associated bloodstream infections (CLABSIs) in the Indian setting. Aim: To study the incidence, aetiology and antimicrobial susceptibility of CLABSI in adult, paediatric and neonatal intensive care units (NICUs) in a tertiary care private hospital in Mumbai, India. Materials and Methods:This is a prospective observational study conducted at the adult, paediatric and NICUs of tertiary care private hospital from 2011 to 2018. CLABSI was defined as per the Centers for Disease Control criteria. Surveillance of CLABSI in the intensive care units (ICUs) was conducted using a form adapted from the International Nosocomial Infection Control Consortium surveillance system. The incidence rates of CLABSI (per 1000 central line days), crude mortality, aetiology and antimicrobial susceptibility were calculated and reported. Results: Six hundred and eighty-six episodes of CLABSI were recorded, and the overall incidence of CLABSI was 5/1000 catheter days, 4.1 in the adult ICU, 5 in the paediatric ICU and 9 in the newborn ICU. Crude mortality in patients with CLABSI in the adult, paediatric and NICUs was 45%, 30% and 7%, respectively. Of the 752 isolates, 80% were Gram negative, 10% Gram positive and 10% yeast. The prevalence of extended-spectrum beta-lactamase producers was 80%, and rates of carbapenem resistance were on an average 50%. Conclusions: The CLABSI rates at a well-equipped tertiary care hospital are still significantly higher than the USA benchmarks. Alarming rates of drug resistance in Gram-negative pathogens were seen.

Trends in antimicrobial susceptibility of salmonella recovered from cattle diagnostic samples in Ohio

Salmonella enterica is an important cause of illness and death in humans. There has been a great deal of efforts to reduce its impact; yet Salmonella infections continue to burden the health of U.S. consumers more than any other foodborne pathogen. Salmonellosis is also an important cause of disease in cattle, causing diarrhea, dehydration, depression, fever, decreased milk production, and anorexia. Surveillance for antimicrobial resistance within healthy food animal populations captures predominantly susceptible Salmonella serovars that are infrequent causes of human illness; however, data from cattle diagnostic submissions can be used to capture trends in antimicrobial susceptibility of strains with a higher public health relevance. Our objective was to evaluate trends in antimicrobial susceptibility of Salmonella recovered from diagnostic samples from clinically ill cattle submitted to the Ohio Department of Agriculture between 2006 and 2017.

Emergence of Haemophilus influenzae with low susceptibility to quinolones and persistence in tosufloxacin treatment.

The use of non-β-lactam agents has increased in Japan due to the prevalence of β-lactam-resistant pathogens. This study aimed to clarify the recent trend of antimicrobial susceptibility and molecular epidemiological features in Haemophilus influenzae. Fifty-seven Haemophilus influenzae isolated from a Japanese teaching hospital in 2017 were characterised, and the data were compared with those of a previous study. The MICs were determined using the broth dilution method. Genetic backgrounds were compared by multilocus sequence typing. The bactericidal activity of tosufloxacin at, or near, the therapeutic Cmax was determined in vitro, with susceptible isolates and quinolone low-susceptible isolates by time-kill assay. The results of the susceptibility tests showed that >90% of isolates were susceptible to cephalosporins and carbapenems, whereas ampicillin-susceptible and clarithromycin-susceptible isolates decreased. Regarding quinolones, low-susceptible isolates were noted in 2017, although all isolates were judged as susceptible. All low-susceptible isolates had an amino acid substitution in GyrA, and two isolates had an additional substitution in ParC. These isolates had different genetic backgrounds. Furthermore, the time-kill kinetic assay using the Cmax of tosufloxacin indicated that the low-susceptible isolates could persist for at least 8hours. This study revealed that Haemophilus influenzae has demonstrated multidrug low-susceptibility in recent years. The low-susceptible isolates had genetic diversity, meaning that resistance occurred independently.

Emerging trends of antimicrobial susceptibility and resistance in burn patients

BackgroundBurn wound infection is a dynamic entity that is one of the major determining factors of the patient’s hospital stay, mortality and morbidity. The analysis of the changing trends in the burn wounds microbiological profile will help deciding a more effective empirical therapy for burn wound infection. ObjectivesTo identify the changing trends of the organisms cultured from the burn wounds during the time of admission, and over a period of last 5 years in the burn unit and their antibiotic susceptibility profile. MethodologyAnalysis of the burn wound culture sensitivity results sent to the microbiology lab on weekly basis and interpretation of the results. ResultsThe gram-positive organisms have become more common in 2017 in the first week of burn admission as compared to previous years. From the second week onwards the gram-negative organisms are the more prevalent organisms. Non-fermenting gram-negative bacilli, Pseudomonas aeruginosa and Staphylococci are the most commonly seen organisms. The patients with a rapid progression of sepsis with burn wound infected with Pseudomonas and non-fermenting gram-negative bacilli will benefit from starting of Colistin at an early stage. Similarly, those with Staphylococci growing in the burn wounds can benefit from Linezolid, Chloramphenicol.

Trends in Bloodstream Infections and Antimicrobial Susceptibilities at a University Hospital in Korea Between 2007 and 2016

Trends in Bloodstream Infections and Antimicrobial Susceptibilities at a University Hospital in Korea Between 2007 and 2016

1167. Trends in Multi-Drug-Resistant Gonorrhea, Gonococcal Isolate Surveillance Project, United States, 1987–2016

Background Neisseria gonorrhoeae’s ability to develop resistance to antibiotics used for treatment and a limited development of new therapies have made this organism one of three urgent threat pathogens in the United States. We provide the first report of US trends in multi-drug-resistant (MDR) and extensively-drug-resistant (XDR) gonorrhea.MethodsThe Gonococcal Isolate Surveillance Project (GISP) monitors trends in antimicrobial susceptibility in N. gonorrhoeae in the United States. Antimicrobial susceptibility testing by agar dilution is performed on urethral isolates from male patients at participating STD clinics. Minimum inhibitory concentration (MIC) are used to identify isolates with resistance or reduced susceptibility using the following criteria: fluoroquinolones (ciprofloxacin [MIC ≥1.0 μg/mL]) and elevated MICs to cephalosporins (cefixime [MIC ≥0.25 μg/mL], ceftriaxone [MIC ≥0.25 μg/mL]) and macrolides (azithromycin [MIC ≥1.0 μg/mL before 2005 and ≥2.0 μg/mL 2005–2016]). In this analysis, MDR is defined as resistance or elevated MICs to ≥2 classes of antimicrobials; XDR as resistance or elevated MICs to ≥3 classes. This classification excludes penicillin and tetracycline due to their long history and high prevalence of gonococcal resistance.ResultsDuring 1987–2016, 159,445 isolates were collected through GISP. In 1998, the first MDR strains were identified. Although only 0.04% of isolates that year, these isolates showed elevated MICs to both cephalosporins and macrolides. By 2010, 1.0% of GISP isolates were MDR with elevated MICs or resistance to two of the cephalosporins, macrolides, or fluoroquinolones. In 2011, the proportion of isolates that were MDR peaked at 1.3%. In 2016, after minor fluctuations, 1.1% of GISP isolates were considered MDR. Only one occurrence of XDR, in 2011, has been seen in GISP. The strain was resistant to fluoroquinolones with elevated MICs to both cephalosporins and macrolides.ConclusionMDR and XDR gonorrhea have remained low over the past three decades; however, dual treatment with cephalosporins and macrolides is the last remaining recommended therapy for N. gonorrhoeae. Until new treatment options become available, a combination of surveillance and ensuring appropriate treatment are needed to delay further resistance.Disclosures All authors: No reported disclosures.

451. High-Frequency of Multi-Drug-Resistant Organisms (MDRO) at University Teaching Hospital (UTH), Lusaka, Zambia

BackgroundAntibiotic resistance is a worldwide problem. Prior studies on patterns of resistance in Zambia depended on laboratory methods that lacked standardization. UTH is a 1,655-bed quaternary care hospital and the primary teaching hospital of Zambia. Since 2015, the microbiology laboratory has used Vitek 2 Compact (bioMerieux, Inc., France) for standardized detection of resistance.MethodsWe conducted a retrospective cross-sectional study of data collected on bacterial isolates analyzed from July 2015 to April 2017. We entered the data into WHONET 5.6 and aggregated it to develop hospital antibiograms. Due to high levels of resistance, we defined susceptible, intermediate, and resistant as >70%, 40–70%, and <40% of isolates sensitive to a drug, respectively. To improve usability, a version replacing the percent susceptible with these categories was developed.ResultsWe analyzed 2,019 isolates to identify susceptibility patterns to commonly used antibiotics at UTH. Escherichia coli and Klebsiella pneumoniae, the most commonly isolated Gram-negative (GN) organisms, were resistant to most drugs including ceftriaxone, indicating high rates of extended-spectrum β-lactamase production. Methicillin-resistant Staphylococcus aureus (MRSA) made up 37% of S. aureus isolates. MRSA and methicillin-susceptible S. aureus were resistant to trimethoprim/sulfamethoxazole, a commonly used drug at UTH. S. pneumoniae was resistant to most drugs against which it was tested.ConclusionMDROs were common at UTH with carbapenems indicated for empiric GN therapy. Further research should assess the extent and depth of antibiotic resistance in Zambia. Antibiograms provide critical information for clinicians to strategically use antibiotics.ReferencesCarroll M, Rangaiahagari A, Musabeyezu E, et al. Five-year antimicrobial susceptibility trends among bacterial isolates from a tertiary health-care facility in Kigali, Rwanda. Am J Trop Med Hyg. 2016;95(6):1277–83.Moremi N, Claus H, Mshana SE. Antimicrobial resistance pattern: a report of microbiological cultures at a tertiary hospital in Tanzania. BMC Infect Dis. 2016;16(1):756.Kumburu HH, Sonda T, Mmbaga BT, et al. Patterns of infections, aetiological agents and antimicrobial resistance at a tertiary care hospital in northern Tanzania. TM and IH. 2017;22(4):454–64. Disclosures E. Heil, ALK-Abelló: Grant Investigator, Research grant. L. Hachaambwa, Centers for Disease Control and Prevention (CDC): Cooperative Agreement to Institution, Financial support for the work described in this abstract was made possible by a cooperative agreement award from the Centers for Disease Control and Prevention (CDC) to the University of Zambia and to the University of Maryland School of Medicine. J. K. Johnson, Q-Linea: Investigator, Research grant. Applied Biocode: Investigator, Research grant.

Antimicrobial Susceptibility Trends Observed in Urinary Pathogens Obtained From New York State.

International guidelines recommend using local susceptibility data to direct empiric therapy for acute uncomplicated cystitis. We evaluated outpatient urinary isolate susceptibility trends in New York State. Nitrofurantoin had the lowest resistance prevalence whereas trimethoprim-sulfamethoxazole and fluoroquinolones had higher prevalences. This study highlights the need for local outpatient antimicrobial stewardship programs.

Bacterial isolation and antimicrobial susceptibility trends: why these are important and how they can be used

Antibiotic resistance is a very real threat to modern standards of human and veterinary healthcare.1 This is a one health problem – we share many antimicrobials, our bacteria are closely...

Changes in epidemiology and antimicrobial susceptibility of nontyphoid Salmonella in children in southern Taiwan, 1997-2016.

This study aimed to investigate the changing trends in serogroup distribution and antimicrobial susceptibility of nontyphoid Salmonella (NTS) isolated from children in the past two decades in Taiwan. This retrospective study enrolled patients aged younger than 18 years with culture-proven NTS infection in a tertiary medical center from 1997 to 2016. Data on age, Salmonella serogroup, culture sample, and antimicrobial susceptibility were obtained from medical records. The rates of Salmonella serogroups and antimicrobial resistance were compared between period 1 (1997-2006) and period 2 (2007-2016). A total of 2075 NTS isolates were identified from 1997 to 2016 (1036 in period 1, 1039 in period 2). The major isolates were from feces (89.1%) and blood (10.4%). The most common serogroup was serogroup B (54.8%), followed by serogroup D (18.8%). There was a significant decline in the proportion of serogroup B with a concomitant rise in serogroup D in the past two decades. In period 2, resistance to cefotaxime and cefixime increased remarkably among serogroup B, whereas resistance to ampicillin increased notably among serogroup D. Furthermore, the incidence of multidrug-resistant (≥3 antibiotics) NTS significantly decreased in both serogroup B and serogroup D in period 2. This study revealed a significant rise in serogroup D with a concomitant decline in serogroup B NTS infection in Taiwanese children. Moreover, antimicrobial resistance to third-generation cephalosporins increased in serogroup B. Continuous surveillance of NTS serogroup distribution and antimicrobial susceptibility is mandatory to formulate therapeutic strategies for NTS infections.