Multicenter survey on hospital-acquired pneumonia and the clinical efficacy of first-line antibiotics in Japan

Outcome evaluation of pharmacist-physician collaborative protocol-based antimicrobial treatment for hospitalized stroke patients with aspiration pneumonia

OBJECTIVES

To evaluate the efficacy and patient outcomes of pharmacist-physician collaborative protocol-based antimicrobial treatment regimens for antimicrobial stewardship.

METHODS

Patients treated for aspiration pneumonia due to stroke within 48 h after admission to Kochi Medical School Hospital (January 2019 to December 2022) were included. Primary outcomes were the cumulative number of days of antimicrobial treatment and length of hospital stay. Secondary outcomes included the percentage of patients under-dosed with first-choice antimicrobial agents and inpatient mortality.

RESULTS

Group A (66 patients) did not receive the antimicrobial treatment protocol, whereas group B (46 patients) did. There were no differences in the patient backgrounds. Group B had a significantly lower percentage of patients who were undertreated with the first-choice antimicrobial agent (9.1 % vs. 42.9 %). There was no significant difference in inpatient mortality between group A and group B (6.1 % vs. 4.3 %). The cumulative number of days of antimicrobial administration and the length of hospital stay were significantly lower in group B: 7.0 days (95 % CI, 6.0-8.0) vs. 9.0 days (95 % CI, 8.0-11.0) for antimicrobial administration, and 28.5 days (95 % CI, 22.0-35.0) vs. 43.0 days (95 % CI, 28.0-55.0) for hospital stay.

CONCLUSIONS

Protocol-based antimicrobial treatment for aspiration pneumonia supports appropriate antimicrobial usage and improves patient quality of life. These findings will assist in the effective treatment of aspiration pneumonia in an aging society.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2019-2020: General view of the pathogens' antibacterial susceptibility

The trends and prevalence of antimicrobial susceptibility of pathogens vary by country, region, and time. Long-term regular surveillance is required to investigate trends in the antimicrobial resistance of various isolated bacterial pathogens. We report the results of a nationwide surveillance on the antimicrobial susceptibility of bacterial respiratory pathogens in Japan conducted by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology. The isolates were collected from clinical specimens obtained from adult patients who visited a collaborating medical facility between June 2019 and December 2020 and were diagnosed with respiratory tract infections by a physician. Antimicrobial susceptibility testing was performed in a centralized laboratory according to the methods recommended by the Clinical and Laboratory Standards Institute. Susceptibility testing was performed for 932 strains (201 Staphylococcus aureus, 158 Streptococcus pneumoniae, 6 S. pyogenes, 136 Haemophilus influenzae, 127 Moraxella catarrhalis, 141 Klebsiella pneumoniae, and 163 Pseudomonas aeruginosa) collected from 32 facilities in Japan. The proportions of methicillin-resistant S. aureus and penicillin-resistant S. pneumoniae were 35.3% and 0%, respectively. In H. influenzae, 16.2% and 16.9% were β-lactamase-producing ampicillin resistant and β-lactamase-negative ampicillin resistant, respectively. Extended-spectrum β-lactamase-producing K. pneumoniae accounted for 5.0% of all K. pneumoniae infections. Carbapenemase-producing K. pneumoniae and multi-drug-resistant P. aeruginosa with metallo-β-lactamase were not detected in this study. This surveillance will be a useful reference for treating respiratory infections in Japan and will provide evidence to enhance the appropriate use of antimicrobial agents.

Efficacy and safety of tedizolid for the treatment of ventilated gram-positive hospital-acquired or ventilator-associated bacterial pneumonia in Japanese patients: Results from a subgroup analysis of a phase 3, randomized, double-blind study comparing tedizolid and linezolid

INTRODUCTION

The results from the phase 3 study that evaluated the efficacy and safety of tedizolid phosphate, an oxazolidinone drug, for the treatment of gram-positive ventilated hospital-acquired bacterial pneumonia (vHABP)/ventilator-associated bacterial pneumonia (VABP) compared with linezolid (VITAL study), have been previously reported. We conducted a subgroup analysis to report the data obtained from Japanese patients enrolled in this study.

METHODS

Patients aged ≥18 years with vHABP/VABP likely to be caused by gram-positive cocci were randomized 1:1 to tedizolid phosphate 200 mg once daily for 7 days or linezolid 600 mg twice daily for 10 days. In both treatment groups, patients with concurrent gram-positive bacteremia were treated for 14 days. Primary efficacy endpoints were day 28 all-cause mortality (ACM) and investigator-assessed clinical response at test-of-cure (TOC) in the intention-to-treat population. Safety outcomes included assessment of treatment-emergent adverse events.

RESULTS

Fifty-three Japanese patients were randomized at received study drug (tedizolid, n = 28; linezolid, n = 25). Demographics and characteristics were generally similar between treatment groups. Rates of day 28 ACM were 10.7% and 20.0% with tedizolid and linezolid, respectively (difference, 9.3%; 95% CI, -10.1 to 28.7). Rates of investigator-assessed clinical cure at TOC were 78.6% and 72.0% with tedizolid and linezolid, respectively (difference, 6.6%; 95% CI, -16.7 to 29.8). Tedizolid phosphate was generally well tolerated and no new safety concerns were observed in the Japanese subgroup.

CONCLUSION

The results from this subgroup analysis suggest generally favorable efficacy and safety of tedizolid in adult Japanese patients with vHABP/VABP. (ClinicalTrials.gov identifier: NCT02019420).

Risk factors for postoperative pneumonia in patients with posterior fossa meningioma after microsurgery

OBJECTIVES

Postoperative pneumonia (POP) is one of the common complications associated with mortality and morbidity. Even so, it has received little intensive research after microsurgical removal for posterior fossa meningioma (PFM). In this study, we aimed to identify perioperative factors for POP after PFM microsurgery to risk-stratify patients and improve clinical outcomes.

PATIENTS AND METHODS

We retrospectively review on all patients who underwent microsurgical resection (n = 321) for PFM from January 2016 to December 2018. To identify the risk factors for POP, we performed univariate and multivariate analyses successively.

RESULTS

44 (13.7%) patients were diagnosed as POP. In accordance with univariate analysis, postoperative Glasgow Coma Scale (GCS) score (<13; p < 0.001), tumor size (≥3cm; p < 0.001), procedure duration (≥3 h; p < 0.001), tumor located in anterior or lateral of brainstem (p < 0.001), estimated blood loss (EBL; > 1000ml; p = 0.001) and brainstem shift (p < 0.001) were associated with POP. By multivariate analysis, the first four were independent risk factors for POP. The study also revealed that POP brought about extended duration of postoperative hospitalization.

CONCLUSION

The incidence of POP following PFM microsurgery was significantly high (13.7%). Apart from tumor size (≥3cm) and procedure duration (≥3 h), GCS score (<13) and tumor located in anterior or lateral of brainstem were independent risk factors for POP. Efforts to reduce the duration of surgery, especially among the large tumors located in anterior or lateral of brainstem, may reduce POP rate and hospitalization stay.

Microorganisms isolated at admission and treatment outcome in sputum smear-positive pulmonary tuberculosis

Cured or completed cases in newly diagnosed sputum smear-positive pulmonary tuberculosis (TB) is 47.7% in Japan in 2016. Aging of TB patients and their underlying conditions could affect treatment outcome. We analyzed the association between the isolation of microorganisms from sputum at admission and the 180-day mortality rate of the sputum smear-positive pulmonary TB patients in Chiba-East Hospital in Japan. Total subjects were 761 (median age: 63 years). Sputum test for microorganisms was conducted in 708 patients. Microorganisms other than the normal oral flora were isolated in 128 cases (18.1%). Details of the isolated microorganisms were as follows: methicillin-resistant Staphylococcus aureus 23 cases, Klebsiella pneumoniae 17 cases, Pseudomonas aeruginosa 16 cases. Mortality was significantly elevated in the patients with those microorganisms than the others (39.8% vs. 10.2%) (P < 0.01). Fifty-one of 128 patients with those microorganisms died, and 10 of them died of infectious disease, which is the most frequent cause of deaths. The factors associated with the isolation of those microorganisms were as follows: respiratory failure (adjusted odds ratio (aOR):2.5 [95% confidence interval (CI) 1.3-4.7]), performance status 3 or 4 (aOR:2.9 [95% CI 1.6-5.4]), serum albumin <3.0 mg/dL (aOR:2.1 [95% CI 1.3-3.6], age of 65 years or older (aOR:2.0 [95% CI 1.2-3.4]). Those strains were isolated from one of sixth patients. Patients with those microorganisms did not always develop infectious diseases; however, treatment outcomes were poor, with higher mortality. The isolations of microorganisms were associated with various underlying conditions, leading to death. Thus, attention should be paid to TB patients with the above factors.

[Retrospective Analysis of Factors Decreasing the Efficacy of Tazobactam/Piperacillin for Pneumonia in Elderly Patients]

　Tazobactam/piperacillin (TAZ/PIPC) is an antimicrobial drug agent with a broad spectrum of antibacterial activity and is recommended as first-line therapy for hospital-acquired pneumonia, nursing- and healthcare-associated pneumonia, and other severe pneumonias. Nevertheless, in clinical settings, TAZ/PIPC is not fully effective in the treatment of pneumonia in the elderly. In the present study, we retrospectively investigated the efficacy of TAZ/PIPC for pneumonia in elderly patients and identified factors that reduced its efficacy. Ninety-nine patients (mean age of 83.4 years and no significant difference in the sex ratio) were included in the present study. The efficacy rate of TAZ/PIPC for pneumonia in elderly patients was 81.8%, which was approximately 7 to 10% lower than that in domestic phase III trials. A multivariate analysis identified the complications of chronic respiratory disease as a significant factor attenuating the therapeutic effects of TAZ/PIPC [odds ratio 4.050, 95% confidence interval (CI) 1.008-16.271]. In conclusion, TAZ/PIPC may not be sufficiently effective for pneumonia in elderly patients with the complications of chronic respiratory disease as a background.

Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.These guidelines are intended for use by healthcare professionals who care for patients at risk for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), including specialists in infectious diseases, pulmonary diseases, critical care, and surgeons, anesthesiologists, hospitalists, and any clinicians and healthcare providers caring for hospitalized patients with nosocomial pneumonia. The panel's recommendations for the diagnosis and treatment of HAP and VAP are based upon evidence derived from topic-specific systematic literature reviews.

Hypoglycemia and glycemic variability are associated with mortality in non-intensive care unit hospitalized infectious disease patients with diabetes mellitus

AIMS/INTRODUCTION

We aimed to identify factors - glycemic control, reactive inflammatory biomarkers or vital signs - associated with mortality in diabetic patients admitted to hospital for various infections (non-intensive care unit).

MATERIALS AND METHODS

We retrospectively analyzed the cases of 620 diabetic patients admitted to hospital for various infections (non-intensive care unit) who underwent glucose monitoring >3 times per day. We extracted data regarding reactive inflammatory biomarkers and vital signs recorded on day 1 of hospital stay, and data on bacteremia and hypoglycemia status, glycemic variability (GV; coefficient of variation and standard deviation) and mean glucose concentrations during the entire hospital stay. Univariate and stepwise multivariate logistic regression analyses were carried out to determine the association between these factors and mortality.

RESULTS

The mortality rate was 10.1%. Reactive inflammatory biomarkers, vital signs and bacteremia were not associated with mortality. According to the results of the adjusted analysis, hypoglycemia showed a significant positive association with mortality, increasing death risk by 266% (odds ratio [OR] 2.66, 95% confidence interval [95% CI] 1.22-5.83; P = 0.0006). High coefficient of variation and standard deviation values were significantly associated with increased mortality, increasing death risk by 18% (OR 1.18, 95% CI 1.01-1.38; P = 0.03) and 9% (OR 1.09, 95% CI 1.01-1.18; P = 0.03), respectively. Mean glucose concentrations were also significantly associated with mortality, increasing death risk by 5% (OR 1.05, 95% CI 1.02-1.08; P = 0.0008).

CONCLUSIONS

Glycemic indices (especially hypoglycemia and GV), rather than reactive inflammatory biomarkers or vital signs, were associated with mortality in non-intensive care unit diabetes mellitus patients with infections.

Usefulness of linezolid in the treatment of hospital-acquired pneumonia caused by MRSA: a prospective observational study

Clinical results for linezolid (LZD) treatment of hospital-acquired pneumonia (HAP) caused by methicillin-resistant Staphylococcus aureus (MRSA), particularly microbiologically evaluable or severe cases, are limited in Japan. A prospective observational study was conducted in order to assess the usefulness of LZD in Japanese patients with MRSA pneumonia. The study tracked fifteen participants treated with LZD for pneumonia who met the criteria of the HAP guidelines and were confirmed to have pneumonia caused by MRSA. Of these, six were severe and 13 had received antibiotic treatment before treatment with LZD. Of the 13 participants assessed for their clinical responses, seven were rated as cures, three were rated as failures, and three were indeterminate. The overall cure rate (cure/cure + failure) was 70.0% (7/10), and the cure rate by severity was 33.3% (1/3) for severe cases and 85.5% (6/7) for moderate cases. The one severe case with a clinical response rating of cure had failed to respond to vancomycin. Among the seven participants with a clinical response rating of cure, the microbiological response was eradication in three, presumed eradication in three, and indeterminate in one. Three serious adverse events occurred in two of the 15 participants, but none were considered to be causally related to LZD. The results suggest that LZD has high potential for severe and multidrug-resistant cases. A higher cure rate was achieved in moderate cases. In cases of pneumonia that are most likely MRSA infections with poor prognosis, it was suggested to be important for patient outcome to implement the most effective therapy before the patient's condition becomes serious.

Prediction of the pathogens that are the cause of pneumonia by the battlefield hypothesis

Commensal organisms are frequent causes of pneumonia. However, the detection of these organisms in the airway does not mean that they are the causative pathogens; they may exist merely as colonizers. In up to 50% cases of pneumonia, the causative pathogens remain unidentified, thereby hampering targeting therapies. In speculating on the role of a commensal organism in pneumonia, we devised the battlefield hypothesis. In the "pneumonia battlefield," the organism-to-human cell number ratio may be an index for the pathogenic role of the organism. Using real-time PCR reactions for sputum samples, we tested whether the hypothesis predicts the results of bacteriological clinical tests for 4 representative commensal organisms: Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis. The cutoff value for the organism-to-human cell number ratio, above which the pathogenic role of the organism was suspected, was set up for each organism using 224 sputum samples. The validity of the cutoff value was then tested in a prospective study that included 153 samples; the samples were classified into 3 groups, and each group contained 93%, 7%, and 0% of the samples from pneumonia, in which the pathogenic role of Streptococcus pneumoniae was suggested by the clinical tests. The results for Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis were 100%, 0%, and 0%, respectively. The battlefield hypothesis enabled legitimate interpretation of the PCR results and predicted pneumonia in which the pathogenic role of the organism was suggested by the clinical test. The PCR reactions based on the battlefield hypothesis may help to promote targeted therapies for pneumonia. The prospective observatory study described in the current report had been registered to the University Hospital Medical Information Network (UMIN) registry before its initiation, where the UMIN is a registry approved by the International Committee of Medical Journal Editors (ICMJE). The UMIN registry number was UMIN000001118: A prospective study for the investigation of the validity of cutoff values established for the HIRA-TAN system (April 9, 2008).

[Acinetobacter spp. infections]

Acinetobacter, which is Gram-negative non-fermentated bacilli, is isolated from natural environment and human body, including skin and gastrointestional tracts of both healthy persons and immunocompromised patients. Acinetobacter can cause bacterial infections, such as blood stream infections and health care-associated pneumonia. The definition of multi-drug resistant (MDR) of Acinetobacter has not been internationally harmonized, however, it is defined when MICs of imipenem, amikacin and ciprofloxacin are 16 microg/ml, 32 microg/ml and 4 microg/ml or higher, respectively, in Japan. Recently, only a few outbreaks by Acinetobacter have been reported in Japan, while outbreaks by Acinetobacter are more common in Western and Asian countries abroad. We should pay attention and caution on outbreaks by Acinetobacter and spread of drug-resistant Acinetobacter as much as we can.

Nicergoline improves dysphagia by upregulating substance P in the elderly

Dysphagia induces silent aspiration, which is a known risk factor for aspiration pneumonia in the elderly. Dysphagia is associated with impaired substance P secretion. Because nicergoline was recently reported to enhance substance P secretion, it may improve dysphagia by upregulating substance P; however, roles for nicergoline in this process have not been demonstrated. We therefore compared the effects of nicergoline on serum substance P and dysphagia with the effects of imidapril, an angiotensin-converting enzyme (ACE) inhibitor whose efficacy in improving dysphagia and preventing pneumonia has been previously demonstrated.We randomly assigned 60 elderly patients with both dysphagia and a previous history of pneumonia to receive either imidapril (5 mg/d; n = 30) or nicergoline (15 mg/d; n = 30) for 6 months. Primary outcomes were the effects of these drugs on the substance P level and dysphagia 4 weeks after the start of treatment. Secondary outcome was the effect of these drugs on pneumonia recurrence during the 6 months of treatment.Significant elevations of serum substance P were obtained by both medications after 4 weeks of treatment. Patients whose dysphagia was improved showed significantly increased serum levels of substance P. There was no statistically significant difference in the overall proportion of patients who showed improvements in dysphagia and pneumonia recurrence with imidapril or nicergoline treatment. Nicergoline, but not imidapril, seemed to be more effective at improving dysphagia and elevating serum substance P in patients with dementia.In conclusion, nicergoline has a comparable effect to ACE inhibitors for improving dysphagia. Nicergoline might be a novel regimen for the treatment of dysphagia in the elderly who are not treatable with ACE inhibitors.

Clinical efficacy of carbapenems on hospital-acquired pneumonia in accordance with the Japanese Respiratory Society Guidelines for management of HAP

Hospital-acquired pneumonia (HAP) is the second most common cause of hospital-acquired infection and is the leading cause of death. In 2002, the Japanese Respiratory Society (JRS) published guidelines for the diagnosis and treatment of HAP (JRS GL 2002). In these guidelines, treatment with carbapenems is recommended for all disease types of HAP, excluding cases of mild or moderate pneumonia with no risk factors, and cases with early-onset ventilation-acquired pneumonia. To evaluate the efficacy of carbapenems on HAP in accordance with JRS GL 2002, we conducted a prospective study of HAP patients treated with carbapenems based on JRS GL 2002. The results of this study were also analyzed based on the revised guidelines published in June 2008 (JRS GL 2008), and the validity of the new guidelines was examined. Of the 33 subjects, 19 were judged as responders to the treatment, corresponding to a response rate of 57.6%. There were 3 deaths, corresponding to a mortality rate of 9.1%. The efficacy of carbapenems for the treatment of HAP based on JRS GL 2002 was confirmed. The severity rating system in JRS GL 2002 has a tendency to overestimate the severity of the cases and may lead to overtreatment in some cases. On the other hand, the severity rating system by JRS GL 2008 seemed to be more accurate and closely correlated with the efficacy of the treatment. It is suggested that JRS GL 2008 is more useful in clinical practice for accurately judging the severity of the disease and initiating appropriate subsequent antibiotic therapy.

Antibacterial activity of carbapenems against clinical isolates of respiratory bacterial pathogens in the northeastern region of Japan in 2007

As the increasing prevalence of resistant strains of respiratory bacterial pathogens has recently been reported, continuous monitoring of the susceptibility of clinical isolates to antibacterial agents is important. We performed a surveillance study focusing on the susceptibility of major respiratory bacterial pathogens in the northeastern region of Japan to carbapenems and control drugs. A total of 168 bacterial strains isolated from patients with respiratory tract infections in 2007 were collected and the minimum inhibitory concentration (MIC) determined. MIC data were subjected to pharmacokinetic/pharmacodynamic analysis with Monte Carlo simulation to calculate the probability of achieving the target of time above MIC with each carbapenem. All Moraxella catarrhalis, Streptococcus pneumoniae, and methicillin-sensitive Staphylococcus aureus isolates were susceptible to carbapenems. Despite the increasing prevalence of β-lactamase-nonproducing ampicillin-resistant strains, all Haemophilus influenzae isolates were susceptible to meropenem. For Pseudomonas aeruginosa, the susceptibility rates for meropenem and biapenem were 76.7%, and the highest probability of achieving pharmacodynamic target (40% of the time above MIC) was obtained with meropenem 0.5 g three times daily as a 4-h infusion (89.4%), followed by meropenem 0.5 g four times daily as a 1-h infusion (88.4%). Carbapenems have retained their position as key drugs for severe respiratory tract infections.

[A case of hospital-acquired pneumonia caused by intermediately susceptible carbapenem Acinetobacter baumannii]

The incidence of Acinetobacter baumannii pneumonia in hospital-acquired pneumonia in Japan is rare. We report a case of ventilator-associated A. baumanii pneumonia. A 69-year-old man admitted for fever was diagnosed with Streptococcus pneumoniae pneumonia based on chest radiography, urine antigen, and sputum examination. Despite appropriate antibiotics, the pneumonia progressed, necessitating intensive respiratory management. Ten days there after, he suffered sudden septic shock and superimposed pneumonia despite both carbapenem and fluoroquinolone administration. A. baumanii was detected from blood and sputum. Piperacilline/tazobactam, amikacin, and intensive care saved his life.

Diagnosis of hospital-acquired pneumonia and methods of testing for pathogens

Hospital-acquired pneumonia is diagnosed in patients who, in addition to abnormal shadowing on chest radiography, have >or=2 of the following: fever, abnormal white blood cell count and purulent discharge. Treatment effect is judged from clinical symptoms and microorganism test results 2-3 days after the start of treatment, and reassessment is made with regard to change, addition or discontinuation of antimicrobial agents. Coordination with the microbiology laboratory is extremely important in diagnosing infectious diseases. Microorganisms isolated from tracheal aspirate at 10(6) cfu/mL (3+), from BAL at 10(4)-10(5) cfu/mL (2+) and from a protected specimen brush at 10(3) cfu/mL (1+) have a high possibility of being the causative microorganisms. Pneumonia can almost be ruled out when no significant microbes are detected from the lower respiratory tract in patients with suspected ventilator-assisted pneumonia (when no change has been made to antimicrobial administration within 72 h). When MRSA or Pseudomonas aeruginosa are not detected in sputum tests, involvement of these drug-resistant bacteria may be considered unlikely, and the case treated accordingly. Involvement of aspiration is suspected when a number of pathogens are observed in lower respiratory tract specimens. When antimicrobials are administered with reference to breakpoint concentrations in Western countries, differences in dosage between these countries and Japan need to be considered.

Definition of hospital-acquired pneumonia and characteristics of guidelines in Japan

Hospital-acquired pneumonia is defined as pneumonia that appears for the first time within 48 h of hospital admission. Special care is needed in treatment because of poor patient conditions, including the underlying disorder, immunocompetence and general status. The 2002 hospital-acquired pneumonia guidelines were reviewed, and the current revisions were made based on those findings with the aim of producing simple and practical guidelines. Differences are seen between hospital-acquired pneumonia in the USA and Japan, and hospital-acquired pneumonia treatment guidelines matched to circumstances in Japan were considered necessary.

Determining treatment effectiveness and period of treatment

Judging the effect of treatment for hospital-acquired pneumonia is difficult using only inflammatory parameters or findings from chest radiography. Preferably, treatment effects should be judged comprehensively from body temperature, findings of chest radiography, inflammatory parameters, status of purulent discharge, bacteriological findings and oxygenation. In VAP, the parameter most closely correlated with prognosis is trend in PaO(2)/FiO(2). Clinical improvements are normally seen within 72 h. Antimicrobials thus should not be changed until the third day unless a dramatic deterioration in symptoms is seen. With the exception of pneumonia from microbes that tend to possess strong resistance, such as Pseudomonas aeruginosa, a treatment period of 7-10 days is adequate if the early-stage drugs are effective. If no improvements in the course are achieved by 3 days after starting treatment, an investigation should be made into whether treatment should be continued or changed to a different antimicrobial agent.