Patterns Of Antimicrobial Use Research Articles

Investigation of antimicrobial use and the impact of antimicrobial use guidelines in a small animal veterinary teaching hospital: 1995–2004

To evaluate patterns of antimicrobial use and the impact of antimicrobial use guidelines at a small animal veterinary teaching hospital. Retrospective study. All antimicrobial prescriptions for dogs and cats admitted to the hospital in 1995 through 2004. Pharmacy records were reviewed, and antimicrobial prescriptions for all dogs and cats admitted during the study period were recorded. Amounts of individual drugs dispensed directly to the intensive care and surgical units were determined. Changes in antimicrobial use during the study period were assessed; changes in antimicrobial use patterns in 2000 through 2004 were evaluated to assess the impact of implementation of antimicrobial use guidelines in 2001. There was a significant decrease in prescriptions/1,000 admissions during the study period. From 1995 to 2004, the use of first-generation cephalosporins, fluoroquinolones, penicillins, and trimethoprim-sulfonamides decreased, whereas the use of metronidazole increased. The use of first-generation cephalosporins, fluoroquinolones, and penicillins decreased from 2000 to 2004. First-line drugs accounted for 90.7% of prescriptions during the study period. The use of third-line drugs decreased from 2000 to 2004. Characterization of antimicrobial use is an important step in defining and evaluating the prudent use of antimicrobials. Whereas the true effect of antimicrobial use guidelines is unclear, these results suggest that the guidelines may have had an effect on antimicrobial prescription patterns in this small animal veterinary teaching hospital. Analysis of objective data regarding antimicrobial use and changes in antimicrobial use patterns over time is important in veterinary practices.

Evaluation of the use of an on-farm system for bacteriologic culture of milk from cows with low-grade mastitis

To determine factors associated with implementation and use of an on-farm system for bacteriologic culture of milk from cows with lowgrade mastitis, including information on how producers used the on-farm bacteriologic culture system to guide antimicrobial selection practices and the resulting impact on patterns of antimicrobial use. Retrospective cohort study. Producers of 81 dairy farms. Farms that used an on-farm system for bacteriologic culture of milk from January 2001 to July 2003 were surveyed. Over half of those producers continuing to use the on-farm culture delayed antimicrobial treatment pending results of bacteriologic culture. Most other producers initiated empirical antimicrobial treatment while bacteriologic culture results were pending. Several barriers to the use of an on-farm system were identified. Significant reductions in rates of antimicrobial use were detected when comparing antimicrobial use rates before and during use of the on-farm system. Most producers chose to treat cows with mastitis caused by gram-positive pathogens with antimicrobials, whereas treatment choices for cows with mastitis caused by gram-negative bacteria and in cases in which no growth was detected varied. Readily available results permit antimicrobial selections to be made on the basis of the causative agent of mastitis. Adoption of an on-farm system for bacteriologic culture of milk may result in significant reductions in the percentage of cows treated with antimicrobials. Decreasing antimicrobial use may have several benefits including preventing unnecessary discarding of milk, decreasing the potential for drug residues in milk, and improving treatment outcomes as a result of targeted treatments.

Stakeholder position paper: Companion animal veterinarian

The total quantity of use in companion animals is generally believed to be relatively small in comparison with antimicrobial use in food animals. Use in companion animals is principally for treatment, whereas the greater proportion of use in food animals is for prophylaxis, metaphylaxis and growth promotion. Therefore, it is important to collect data on end use in companion animals so that overall estimates of use in companion animals can be generated and separated from estimates for food animals. However, data from antimicrobial use in companion animals are extremely limited and no serious attempts to collect such data have ever been made in the United States. The lack of usage data in is concomitant with the dearth of information on antimicrobial resistance in companion animals. Companion animals have been involved in the transmission to humans of, or become infected with, foodborne zoonotic bacteria such as Salmonella and Campylobacter. Companion animals are an integral part of the ecology of antimicrobial resistance through their contact with food animals and exposure to antimicrobials for disease treatment and through contact with humans and the environment. In the practice of companion animal medicine, antimicrobial use data are important for understanding the potential impact on companion animal heath posed by antimicrobial resistance transferred from food animals, humans and the environment, and the threat to humans and other companion animals posed by antimicrobial use in companion animals. Basic information on the patterns and quantities of antimicrobial use in combination with resistance surveillance data, could help companion animal veterinarians understand the potential for development, or evidence of, an antimicrobial resistance problem in their practices, the role of companion animals in the overall epidemiology of antimicrobial resistance, and for comparison with local, regional, or national data. The combination of data from either a sentinel site system of clinics or a use survey with national data from the pharmaceutical industry should provide sufficient data to credibly estimate the total volume and patterns of antimicrobial use in companion animal medicine. The time and effort for use monitoring or to complete a survey would likely become burdensome. Practice management software now utilized at most companion animal clinics could be used to generate antimicrobial use data as well as patient population data as surrogate for the true population at risk for patient encounters in a companion animal practice.

Analysis of antimicrobial resistance among gram-negative bacilli and antimicrobial use in intensive care unit patients for 5 years in a veterans affairs medical center

Background: Gram-negative bacilli antimicrobial resistance remains a significant problem for patients in the intensive care unit (ICU). Patterns of antimicrobial use may be a contributing factor. Methods: Gram-negative bacilli from ICU patients of a Veterans Affairs (VA) medical center were tested to determine in vitro antimicrobial susceptibility (205 isolates in 1995 and 209 in 1999). Antimicrobial use was calculated from 1995 through 1999. Results: For Pseudomonas aeruginosa , significant declines in susceptibility to ciprofloxacin (medical ICU [MICU] individually and all units) and aztreonam (all units) were noted. For gram-negative bacilli that was non-P aeruginosa , significant increases in susceptibility to ceftazidime (MICU, surgical ICU, and all units), gentamicin (all units), and ticarcillin/clavulanate (MICU) were noted. The most notable trends in antimicrobial usage were sharp increases in fluoroquinolone use in the MICU and surgical ICU and substantial decreases in the use of third-generation cephalosporins, monobactams, and aminoglycosides. In each instance of significant change in the susceptibility of a group of organisms to an antibiotic, there was a corresponding inverse change in the use of the antibiotic and/or its antimicrobial category (except for aztreonam). Conclusions: Significant changes in antimicrobial use may affect certain gram-negative bacilli antimicrobial susceptibilities in ICUs. (Am J Infect Control 2002;30:411-6.)

Prevalence of surgical-site infections and patterns of antimicrobial use in a large tertiary-care hospital in Ho Chi Minh City, Vietnam.

Few studies have been conducted in Vietnam on the epidemiology of healthcare-associated infections or antimicrobial use. Thus, we sought to determine the prevalence of and risk factors for surgical-site infections (SSIs) and to document antimicrobial use in surgical patients in a large healthcare facility in Vietnam. We conducted a point-prevalence survey of SSIs and antimicrobial use at Cho Ray Hospital, Ho Chi Minh City, a 1,250-bed inpatient facility. All patients on the 11 surgical wards and 2 intensive care units who had surgery within 30 days before the survey date were included. Of 391 surgical patients, 56 (14.3%) had an SSI. When we compared patients with and without SSIs, factors associated with infection included trauma (relative risk [RR], 2.65; 95% confidence interval [CI95], 1.60 to 4.37; P < .001), emergency surgery (RR, 2.74; CI95, 1.65 to 4.55; P < .001), and dirty wounds (RR, 3.77; CI95, 2.39 to 5.96; P < .001). Overall, 198 (51%) of the patients received antimicrobials more than 8 hours before surgery and 390 (99.7%) received them after surgery. Commonly used antimicrobials included third-generation cephalosporins and aminoglycosides. Thirty isolates were identified from 26 SSI patient cultures; of the 25 isolates undergoing antimicrobial susceptibility testing, 22 (88%) were resistant to ceftriaxone and 24 (92%) to gentamicin. Our data show that (1) SSIs are prevalent at Cho Ray Hospital; (2) antimicrobial use among surgical patients is widespread and inconsistent with published guidelines; and (3) pathogens often are resistant to commonly used antimicrobials. SSI prevention interventions, including appropriate use of antimicrobials, are needed in this population.

Level and percentage recovery of resistance to oxytetracycline and oxolinic acid of bacteria from shrimp ponds

The bacterial level of the water, sediment and cultured shrimp ( Penaeus monodon) from different ponds were determined using a general medium, a presumptive Vibrio medium and a presumptive Pseudomonas– Aeromonas medium. Samples were taken from ponds that had not used any antimicrobial, ponds that had previously used and also ponds that were currently using oxolinic acid (OXA). The bacterial level in the sediment was higher than in the water using all three media. More bacteria existed in the pond system than in the receiving environment. Shrimp hepatopancreas harbored more bacteria than the lymphoid organ. The Vibrio density of the pond and bacterial levels in the shrimp were correlated with the use of the antimicrobial. The Vibrio level of the pond samples and microbial density of shrimps were higher from ponds that had not used any antimicrobials. The percentage recoveries of resistance to oxytetracycline (OTC) and OXA in bacteria from shrimp ponds and cultured shrimps were also determined using Zobell's marine agar, Pseudomonas– Aeromonas selective agar and thiosulfate citrate bile sucrose agar (TCBS) with the addition of either 25 μg/ml OTC or 25 μg/ml OXA. Presumptive Vibrio bacteria and other bacterial taxa recovered from the pond/receiving water/sediment from all three sites showed some degree of resistance to OTC and OXA. However, a higher percentage recovery of strains resistant to OTC than to OXA was observed among the presumptive vibrios and other bacterial taxa. Pseudomonas and Aeromonas bacteria were more resistant to OXA compared with the vibrios. All bacterial taxa resistant to OTC were more readily recovered from the water samples than from the sediment samples. In general, between the samples from the pond and from the receiving environment, a higher percentage of resistant strains was observed in the latter. Higher percentage recovery of bacteria resistant to OXA was observed in shrimp from ponds currently using OXA than those from ponds that had not used any or those that had previously used them. The results of the present study showed that the percentage recovery of resistance reflected the pattern of antimicrobial use.

Antibiotic resistance of bacteria from shrimp ponds

The incidence of antibiotic resistance was compared in bacteria isolated from pond water, pond sediment, water and sediment from the receiving environment (area where water from pond drains, which is 0 and 50 m away from the exit gate, in this study) and cultured shrimp from ponds that have not used any antimicrobials, ponds that have previously used antimicrobials and ponds that are currently using oxolinic acid. Most of the bacteria isolated from all sample and pond type were Vibrios. Among the Vibrios, V. harveyi were most commonly isolated. Multiple antibiotic resistance (MAR) to at least two antimicrobials was highest in ponds currently using oxolinic acid (24% of bacteria isolated from such ponds), followed by those that have previously used antimicrobials (19%) and the least was those from ponds that have not used any antimicrobials (17%). The lowest incidence of antibiotic resistance was observed in ponds that have not used any antimicrobials (41% of the isolates from such ponds). Among the individual antibiotics, incidence of resistance to oxytetracycline was highest (4.3% of the total number of isolates) followed by furazolidone (1.6%), oxolinic acid (1%) and chloramphenicol (0.66%). Resistance to individual chemotherapeutants did not reflect the pattern of antimicrobial use with ponds that have previously used antimicrobials showing the highest incidence of resistance to one antimicrobial (12% of total isolates from such ponds). Resistance to both oxolinic acid and furazolidone (15% of total number of isolates) was highest compared to other antimicrobial resistance profiles (1–12%). Multiple antimicrobial resistance and intermediate reaction to at least one antimicrobial are associated with antimicrobial use.

Use and misuse of antimicrobial agents in a general hospital in the AIDS era

A prevalence study was carried out to ascertain the pattern of antimicrobial use, costs and relevance in a general hospital during the AIDS era. All patients receiving antimicrobials were studied. Antimicrobials were divided into antibacterial drugs and others and the costs evaluated in US dollars. Of 1526 patients surveyed, 455 (29.8%) were receiving 664 courses of antimicrobials: 109 (7.2%) as prophylaxis and 346 (22.6%) as treatment. Fifteen percent of courses involved non-antibacterial drugs. In 188 patients (40.9% of those treated) treatment was inadequate, usually because of incorrect drug choice. Daily cost of antimicrobials was $14 953. AIDS accounted for 3% of all patients, 9% of those receiving antimicrobials, 19.7% of antimicrobial usage and 9.6% of the antimicrobial expenditure. Misuse occurred in 43% of non-HIV patients and 17% of those with HIV. Thus, despite a disproportionate contribution of patients with AIDS, adequacy of use of antimicrobials was better in this population.

Are we facing a 'post-antibiotic era'?--a review of the literature regarding antimicrobial drug resistance.

Since the introduction of antibiotics in the 1940s, antibiotic resistance has become an increasing problem. Today, multiple-antibiotic resistance is commonly associated with a number of clinically important pathogens and is therefore an important issue in clinical nursing practice. Epidemiological studies identify a number of important factors associated with increases in antimicrobial resistance. These include patterns of antimicrobial use, changes in medical and veterinary care and social practices affecting the transmission of microbes. Bacterial mechanisms of antibiotic resistance and the genetics of resistance-gene transfer are explored, with the intention of developing nurses' knowledge and understanding of control measures.

Antimicrobial Use and Resistance in Eight US Hospitals: Complexities of Analysis and Modeling

Antimicrobial Use and Resistance in Eight US Hospitals: Complexities of Analysis and Modeling

Patterns of antimicrobial use and antimicrobial resistance among healthy children in Bolivia.

To determine the incidence of antimicrobial-resistant, nonpathogenic Escherichia coli among healthy children aged 6-72 months in Camiri town and a rural village, Javillo, in south-eastern Bolivia. A community-based survey: stool samples were obtained from 296 healthy children selected by modified cluster sampling in Camiri and all 25 eligible children in Javillo. E. coli isolates were tested for antimicrobial susceptibility according to the standard disc diffusion method. By a questionnaire survey of 12 pharmacies and by using simulated patients, we investigated the antimicrobial availability and the usage patterns in Camiri town. In Camiri, over 90%, and in Javillo over 70% of children carried E. coli resistant to ampicillin, trimethoprim-sulphamethoxazole (TMP/SMX) or tetracycline. Overall, 63% of children carried E. coli with multiple resistance to ampicillin, TMP/SMX, tetracycline and chloramphenicol. In the simulated patients study, antimicrobials were dispensed inappropriately for 92% of adults and 40% of children with watery diarrhoea, and were under-prescribed for males with urethral discharge (67%) or females with fever and dysuria (58%). The dose and/or duration of antimicrobials dispensed was almost always too low. Our study showed a disturbingly high prevalence of carriage of nonpathogenic E. coli resistant to antimicrobials. The prevalence of resistance to ampicillin and TMP/SMX was higher than that previously reported in developing countries. The existence of a large reservoir of resistance genes in healthy individuals in developing countries represents a threat to the success of antimicrobial therapy throughout the world. Programmes to improve rational and effective drug use in developing countries are urgently needed.

Variations in Antimicrobial Use and Cost in More Than 2,000 Patients with Community-acquired Pneumonia

PURPOSE: To assess the patterns of antimicrobial use, costs of antimicrobial therapy, and medical outcomes by institution in patients with community-acquired pneumonia. PATIENTS AND METHODS: The route, dose, and frequency of administration of all antimicrobial agents prescribed within 30 days of presentation were recorded for 927 outpatients and 1328 inpatients enrolled in the Pneumonia Patient Outcomes Research Team (PORT) multicenter, prospective cohort study. Total antimicrobial costs were estimated by summing drug costs, using average wholesale price for oral agents and institutional acquisition prices for parenteral agents, plus the costs associated with preparation and administration of parenteral therapy. Thirty-day outcome measures were mortality, subsequent hospitalization for outpatients, and hospital readmission for inpatients. RESULTS: Significant variation ( P <0.05) in prescribing practices occurred for 17 of the 23 antimicrobial agents used in outpatients across 5 treatment sites, and for 18 of the 20 parenteral agents used in inpatients across 4 treatment sites. The median duration of antimicrobial therapy for treatment site ranged from 11 to 13 days for outpatients ( P = 0.01), and from 13 to 15 days for inpatients ( P = 0.49). The overall median cost of antimicrobial therapy was $12.90 for outpatients, and ranged from $10.80 to $58.90 among treatment sites ( P <0.0001). The overall median cost of antimicrobial therapy was $228.70 for inpatients, and ranged from $183.70 to $315.60 among sites ( P <0.0001). Mortality and hospital readmission for inpatients were not significantly different across sites after adjusting for baseline differences in patient demographic characteristics, comorbidity, and illness severity. Although subsequent hospitalization for outpatients differed by site, the rate was lowest for the site with the lowest antimicrobial costs. CONCLUSION: Variations in antimicrobial prescribing practices by treatment site exist for outpatients and inpatients with community-acquired pneumonia. Although variation in antimicrobial prescribing practices across institutions results in significant differences in antimicrobial costs, patients treated at institutions with the lowest antimicrobial costs do not demonstrate worse medical outcomes.

THE IMPACT OF ANTIMICROBIAL USE ON THE EMERGENCE OF ANTIMICROBIAL-RESISTANT BACTERIA IN HOSPITALS

Abundant evidence suggests a relationship between antimicrobial resistance and use, including models, consistent associations between resistance and antimicrobial use in hospitals, concomitant variation in resistance as antimicrobial use varies, and a dose-response relationship for many pathogen/antimicrobial combinations. Much of the evidence is from studies performed in single hospitals. Most multicenter studies on resistance have not included data on antimicrobial usage. Despite this substantial body of evidence, some studies have not demonstrated an association between antimicrobial resistance and use, suggesting other contributing factors such as cross transmission, interhospital transfer of resistance, a community contribution to resistance, or a complex relationship between resistance and the use of a variety of antimicrobials. Understanding the problem of antimicrobial resistance in a hospital cannot be achieved without knowledge of the hospital's pattern of antimicrobial use.

Enforcing a policy for restricting antimicrobial drug use.

An institution's experience in enforcing a policy for restricting the use of antimicrobial agents is described. A policy to restrict the use of eight intravenous antimicrobial agents had been in place for two years at a large county teaching hospital but had never been enforced. In 1994 an organized effort to enforce the policy was begun. Memorandums were sent to all medical staff, residents, pharmacists, and nurses informing them that the policy would be diligently enforced. Before a restricted antimicrobial could be dispensed, the approval of a physician specializing in infectious diseases was required. Under the direction of the pharmacy and therapeutics committee and an antimicrobial subcommittee, a specially hired team of pharmacists started to encourage more effective and economical prescribing of antimicrobials. During a nine-month period after enforcement began, use of the restricted antimicrobials declined, and use of nonrestricted antimicrobials increased. After two months, acquisition costs for the restricted drugs had been reduced by more than $82,000; however, a similar increase in acquisition costs for nonrestricted antimicrobials occurred. As a result, one nonrestricted agent was reclassified as restricted, and inservice sessions were held to teach prescribes about the appropriate use of another agent. In general, physicians were very compliant with the antimicrobial-restriction policy; the greatest resistance was encountered from surgical residents. Some-pharmacists needed warnings beyond the initial memorandum. Enforcement of an antimicrobial-restriction policy led to decreased use of the restricted drugs and substantial cost avoidance. As new patterns of antimicrobial use emerged, the restriction policy was modified as necessary.

Update on Clostridium difficile-induced colitis, Part 1

Recent findings on the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of Clostridium difficile-induced colitis (CDIC) are discussed. CDIC is a gastrointestinal disorder that results from colonization by and overgrowth of C. difficile. Among patients in the community who are treated with an oral antimicrobial, only 1 to 3 individuals per 100,000 develop CDIC, compared with as many as 1 per 100 hospitalized patients treated with an antimicrobial. The requirements for CDIC are (1) a readily available source of C. difficile; (2) exposure to drugs, most commonly certain antimicrobials, that disrupt the normal colonic microflora; (3) production of the requisite cytotoxins by the C. difficile strain colonizing the colon; and (4) the presence of individual risk factors, including advanced age, severe underlying illness, and a prolonged hospital stay. Among the varied clinical manifestations of CDIC, diarrhea is predominant and is often the sole symptom. In more severe cases, fever and leukocytosis are also present. The formation of pseudomembranous plaques is pathognomonic but relatively infrequent. Presumptive diagnosis is usually based on a positive cytotoxin assay result in the symptomatic patient. Patients who respond to discontinuation of the inciting drug or drugs should not be treated indiscriminately with antimicrobials. Asymptomatic carriers should not be treated, and a period of watchful waiting may be advisable in mild cases. When treatment is necessary, oral metronidazole is the agent of choice in all but the most severe cases. Whether oral metronidazole is therapeutically equivalent to oral vancomycin in severe CDIC is controversial. Regardless of the antimicrobial used, some patients suffer a recurrence of CDIC and a few have several relapses. There have been no comparative studies of treatment for relapsing CDIC. Of the investigational treatments, the tiacumicin macrolides and the yeast Saccharomyces boulardii appear most promising. Diagnostic assays based on the polymerase chain reaction should allow more timely intervention. Health care professionals who improve their understanding of CDIC will be better able to recognize the disorder, select the best treatment, and perhaps reduce the frequency of CDIC in hospitalized patients by working to alter patterns of antimicrobial use.

Interim Report on Drug Utilization Review of Community Acquired, Nursing Home Acquired and Nosocomial Pneumonia: Clinical, Bacteriological and Radiological Spectrum

OBJECTIVES: To review the epidemiology of community acquired, nursing home acquired and nosocomial pneumonia in terms of clinical. bacteriological and radiological features and to examine the spectrum of and response to antimicrobial agents used in its management.DESIGN: A retrospective review of all hospital records with pneumonia coded in the discharge diagnoses over a five‐year period from April 1987 to March 1993.SETTING: University‐affiliated, community‐based hospital with a mixed primary to tertiary referral base.PATIENT SELECTION: Patients included in the study were all patients with a diagnosis of pneumonia as identified by computer records of diagnostic codes of all discharges: patients with a specific diagnosis of Pneumocystis carinii pneumonia were excluded. One thousand seven hundred and eighty‐two patients out of 74.435 discharges over the five‐year period met the inclusion criteria.RESULTS: The initial 1300 of the 1782 cases of pneumonia are included in this interim report. Mean age was 65 years (range 16 to 103) wilh 60% men and 40% women. Sixty‐two percent of all cases were community acquired, 29% were hospital acquired and 9% were nursing home acquired. One thousand two hundred and sixty (97%) patients had al least one concomitant medical condition. mainly cardiac disease. alcoholism and chronic obstructive lung disease. Chest roentgenogram was abnormal in 98%. Cultures of sputum, bronchoalveolar lavage fluid, blood and/or serology revealed positive results in 785. The most common pathogens were Streptococcus pneumoniae (154). Haemophilus influenzae (147). Staphylococcus aureus (111) and Pseudomonas aeruginosa (100). In the group with community acquired pneumonia, S pneumoniae and H influenzae predominated. In the hospital acquired pneumonia group S aureus and P aeruginosa were more common. although S pneumoniae remains a significant pathogen. In the nursing home acquired pneumonia group. Gram‐negative agents were the most common. The pattern of antimicrobial agents used, usually begun empirically when culture results are pending. showed that the majority of patients was treated with combination antibiotics for both Gram‐positive and Gram‐negative coverage. Ceftriaxone was usually prescribed with either erythromycin or clindamycin. In about half the patients. the ceftriaxone dose was 1 g per clay. Ninety‐six (7%) patients developed complications of pneumonia and 207 (16%) patients required intensive care unit admission. Nine hundred and fifty‐nine (73%) patients were cured or improved at time of discharge, 21 ( 1.5%) patients discharged themselves against medical advice and 320 (25%) patients died during admission to hospital, of whom 165 cases had pneumonia listed as a cause on the death certificate.CONCLUSIONS: Pneumonia remains a significant illness with high morbidity and mortality. Those affected and requiring hospitalization are elderly and ill. The most common pathogens overall continue to be S pneumoniae and H influenzae, although Gram‐negative organisms and S aureus were also significant agents in nosocomial and nursing home acquired pneumonia. The high percentage of Gram‐negative infections in the community acquired group has not been previously described and may represent a change in the pattern of pathogens affecting this group. Three of the 53 community acquired cases in whom P aeruginosa was implicated were detected on blood cultures and were definitely pathogens. Ten of the 53 patients had underlying bronchiectasis or cystic fibrosis and one patient had a history of hematogenous malignancy. Whether the finding of P aeruginosa represents true pathogenicity or colonization in the 53 cases is difficult to differentiate in a retrospective fashion. However. all but two received antibiotic therapy. and 10 of the 40 survivors in this subgroup received adequate coverage for pseudomonas. Although yield from routine investigations is only 60% (785 of 1300 patients in this study), cultures of blood and sputum should be sent in all patients as it may help to narrow choice of antimicrobial agents and aid in oral step‐down selection . Only in select patients should serum serology and more costly and invasive procedures such as bronchoscopy and thoracocentesis be done. It appears that the current pattern of antimicrobial use is appropriate for management of pneumonia given the pattern of offending organisms seen. In the present study, pragmatic use of ceftriaxone at 1 g/24h in these sick patients appeared to result in a therapeutic outcome similar to other antibiotic combination therapy.

Pattern of Antibiotic Use in Medical Wards of a University Hospital, Bangkok, Thailand

Inappropriate use of antimicrobial agents has been found to be common in various parts of the world, but there have been few studies in developing countries. In Siriraj Hospital, Mahidol University, the largest university Hospital in Thailand, a study was performed to estimate the appropriateness of the use of antimicrobial drugs. Each of the nine medical wards was sampled in random order, and daily surveillance of all patients over two 2-week periods identified 307 of the total 690 patients to have been prescribed an antibiotic. In only 27 of the 307 patients was the use of antibiotics entirely appropriate. The main problem was the use without evidence of infection (in 110 of the 307 patients), which we estimate would result in the loss for the hospital of approximately $40,000 (U.S.) each year on the medical wards alone. The choice of antimicrobial agents and pharmacokinetic considerations were also inappropriate. Use of expensive drugs where cheaper ones were available, however, was not frequent (71 of the 655 prescriptions). Attempts to rectify antimicrobial misutilization, based on the results of this study, can be focused specifically at improving clinical recognition of infectious disease by education. The pattern of antimicrobial use in a university teaching hospital in Bangkok, Thailand, reflects a high proportion of misuse. The need for rationalization of antimicrobial use is urgent.

Resistance of gram-negative bacilli as related to hospital use of antimicrobial agents.

The development of resistance of gram-negative bacilli, which are common nosocomial pathogens, is an increasing problem. It is generally accepted that this resistance may directly reflect the frequency of use of various antimicrobial agents. Because our institution experienced in 1976 a dramatic change in the pattern of antimicrobial use, primarily a marked decrease in prescribing cephalosporins, we attempted to evaluate retrospectively the effects of this change upon the resistance of gram-negative bacilli that are common nosocomial pathogens. Susceptibilities of Klebsiella and Providencia spp., Pseudomonas aeruginosa, and Serratia marcescens were determined for the years 1975 to 1979. Not unexpectedly, we observed a substantial decrease in cephalosporin resistance. An unexpected finding was a decrease in aminoglycoside resistance, despite increased use of these agents. The possibility that decreased cephalosporin use may lead to decreased aminoglycoside resistance is an intriguing and provocative thesis which can only be speculative at this time but which would seem worthy of additional formal investigation.