Similarities and differences between doxycycline and minocycline: clinical and antimicrobial stewardship considerations.

Doxycycline and, to a lesser extent, minocycline, have been used for decades to treat various serious systemic infections, but many physicians remain unfamiliar with their spectrum, interpretation of susceptibility results, pharmacokinetic/pharmacodynamic (PK/PD) properties, optimal dosing regimens, and their activity against MRSA, VRE, and multidrug-resistant (MDR) Gram-negative bacilli, e.g., Acinetobacter sp. This article reviews the optimal use of doxycycline and minocycline to treat a variety of infections and when minocycline is preferred instead of doxycycline.

Nitrofurantoin safety and effectiveness in treating acute uncomplicated cystitis (AUC) in hospitalized adults with renal insufficiency: antibiotic stewardship implications.

Nitrofurantoin remains a key oral antibiotic stewardship program (ASP) option in the treatment of acute uncomplicated cystitis (AUC) due to multi-drug resistant (MDR) Gram negative bacilli (GNB). However, there have been concerns regarding decreased nitrofurantoin efficacy with renal insufficiency. In our experience over the past three decades, nitrofurantoin has been safe and effective in treating AUC in hospitalized adults with renal insufficiency. Accordingly, we retrospectively reviewed our recent experience treating AUC in hospitalized adults with decreased renal function (CrCl < 60 ml/min) with nitrofurantoin. Excluded were complicated urinary tract infections. Urinary isolated susceptibility testing was done by micro broth dilution (MBD). Treatment duration was 5-7 days. Cure was defined as eradication of the uropathogen and failure was defined as minimal/no decrease in urine colony counts. Of 26 evaluable patients with renal insufficiency (CrCl < 60 ml/min), nitrofurantoin eradicated the uropathogen in 18/26 (69%) of patients, and failed in 8/26 (31%). Of the eight failures, five were due to intrinsically resistant uropathogens, e.g., Proteus sp., and one failure was related to an alkaline urine. Of the treatment failures, only two were due to renal insufficiency, i.e., CrCl < 30 ml/min. Since there are few oral antibiotics available to treat AUC due to MDR GNB uropathogens, these results have important ASP implications. Currently, nitfurantoin is not recommended if CrCl < 60 ml/min. In our experience, used appropriately against susceptible uropathogens, nitrofurantoin was highly effective in nearly all patients with CrCl = 30-60 ml/min., and only failed in two patients due to renal insufficiency (CrCl < 30 ml/ml).

Are atypical lymphocytes present with viral influenza-like illnesses (ILIs) in hospitalized adults?

The purpose of this investigation was to determine if atypical lymphocytes were of diagnostic value in viral influenza-like illnesses (ILIs) in hospitalized adults during the influenza season. Are atypical lymphocytes present with viral ILIs in hospitalized adults? During the influenza season, hospitals are inundated with influenza and viral ILIs, e.g., human parainfluenza virus-3 (HPIV-3). Without specific testing, clinically, it is difficult to differentiate influenza from ILIs, and surrogate influenza markers have been used for this purpose, e.g., relative lymphopenia. The diagnostic significance of atypical lymphocytes with ILIs is not known. We retrospectively reviewed the charts of 35 adults admitted with pneumonia due to viral ILI. The diagnosis of 14 patients was by respiratory virus polymerase chain reaction (PCR). During the 2015 influenza A season with ILIs, atypical lymphocytes were not present in influenza A (H3N2) patients but atypical lymphocytes were present in some ILIs, particularly HPIV-3. With viral ILIs, atypical lymphocytes should suggest a non-influenza viral diagnosis.

The clinical usefulness of lymphocyte:monocyte ratios in differentiating influenza from viral non-influenza-like illnesses in hospitalized adults during the 2015 influenza A (H3N2) epidemic: the uniqueness of HPIV-3 mimicking influenza A.

During influenza epidemics, influenza-like illnesses (ILIs) viruses cocirculate with influenza strains. If positive, rapid influenza diagnostic tests (RIDTs) identify influenza A/B, but false-negative RIDTs require retesting by viral polymerase chain reaction (PCR). Patient volume limits testing during influenza epidemics, and non-specific laboratory findings have been used for presumptive diagnosis pending definitive viral testing. In adults, the most useful laboratory abnormalities in influenza include relative lymphopenia, monocytosis, and thrombocytopenia. Lymphocyte:monocyte (L:M) ratios may be even more useful. L:M ratios <2 have been used as a surrogate marker for influenza, but there are no longitudinal data on L:M ratios in hospitalized adults with viral ILIs. During the 2015 influenza A (H3N2) epidemic at our hospital, we reviewed our experience with L:M ratios in 37 hospitalized adults with non-influenza viral ILIs. In hospitalized adults with non-influenza A ILIs, the L:M ratios were >2 with human metapneumovirus (hMPV), rhinoviruses/enteroviruses (R/E), and respiratory syncytial virus (RSV), but not human parainfluenza virus type 3 (HPIV-3), which had L:M ratios <2. HPIV-3, like influenza, was accompanied by L:M ratios <2, mimicking influenza A (H3N2). In influenza A admitted adults, L:M ratios <2 did not continue for >3 days, whereas with HPIV-3, L:M ratios <2 persisted for >3 days of hospitalization.

Predictors of ertapenem therapeutic efficacy in the treatment of urinary tract infections (UTIs) in hospitalized adults: the importance of renal insufficiency and urinary pH.

In hospitalized adults acute uncomplicated cystitis (AUC) and catheter associated bacteriuria (CAB) may be treated with oral antibiotics. With AUC or CAB due to extended spectrum ß-lactamase (ESBL) + Gram negative bacilli (GNB) physicians often use intravenous therapy, e.g., ertapenem. We reviewed our recent experience in hospitalized adults with AUC and CAB treated with ertapenem. Therapeutic efficacy of ertapenem was assessed by decreased pyuria/bacteriuria, and elimination of the uropathogen. The effectiveness of ertapenem in the presence of renal insufficiency (CrCl < 50 ml/min) and acid and alkaline urinary pH were evaluated. In addition, rapidity of eradication of bacteriuria was assessed by time to negative urine cultures (TTNC). In those with an acid urinary pH ertapenem was highly effective in eliminating bacteriuria (TTNC < 3 days). TTNC was prolonged ( >3 days) in patients with decreased renal function and alkaline urinary pH. We reviewed 45 hospitalized adults with AUC or CAB to determine if renal insufficiency and or alkaline urinary pH affected ertapenem efficacy. In the 33 adult hospitalized patients with AUC and 12 with CAB, we found that ertapenem was consistently effective in eliminating the GNB bacteriuria. In hospitalized adults, the presence of renal insufficiency and acid urine, bacteriuria was eliminated in < 3 days. However, in those with renal insufficiency and an alkaline urine pH, the rapidity of cure, i.e., time to negative cultures (TTNC) was prolonged, i.e., > 3 days which has not been previously reported.

Unnecessary repeat Clostridium difficile PCR testing in hospitalized adults with C. difficile-negative diarrhea.

The aim of this study was to determine the extent and associated costs of repeat Clostridium difficile stool polymerase chain reaction (PCR) assays in patients with initially negative PCRs. C. difficile stool PCRs were done on adult hospitalized patients with diarrhea. The number/time course of repeat PCRs on initially negative PCR patients was determined. Of 5,027 C. difficile stool PCRs, 814 (16.2 %) were positive and 4,213 (83.8 %) were negative. Ninety-seven of the initially PCR-negative patients had >2 repeat tests 1-59 days after the initial negative stool PCR. Repeat negative PCR testing rarely resulted in a subsequent positive result (0.05 %). The unnecessary costs of 97 repeat PCRs was $32,658.00. Many of these patients were originally given empiric oral anti-C. difficile therapy, in spite of repeatedly negative PCRs.

Fever of unknown origin (FUO) in an immunocompetent adult due to cytomegalovirus (CMV) with polyclonal gammopathy.

Fever of unknown origin (FUO) may be due to infection, malignancy, collagen vascular/inflammatory disorders, or other causes. Cytomegalovirus (CMV) infection is a rare cause of FUO in immunocompetent adults. We present a case of FUO due to CMV in an immunocompetent adult with polyclonal gammopathy on serum protein electrophoresis (SPEP).

Neurosurgically related nosocomial Acinetobacter baumannii meningitis: report of two cases and literature review.

Nosocomial meningitis is an uncommon complication of neurosurgical procedures, although nosocomial Gram-negative bacillary meningitis does occur occasionally in neurosurgical intensive care units (NSICUs). Acinetobacter baumannii is a rare cause of nosocomial meningitis, and is an even rarer cause of meningitis outbreaks in NSICUs. We report two cases of A. baumannii meningitis in an NSICU due to suboptimal aseptic technique in obtaining cerebrospinal fluid (CSF) specimens. After institution of infection control measures, i.e. aseptically collecting CSF specimens from distal external ventricular drain ports, there were no further cases. This report also reviews nosocomial Acinetobacter meningitis in adult neurosurgical patients.

Daptomycin resistance and treatment failure following vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) mitral valve acute bacterial endocarditis (ABE).

Acute bacterial endocarditis (ABE) is most commonly due to virulent pathogens, i.e., Staphylococcus aureus. S. aureus ABE may be due to methicillin-sensitive (MSSA) or methicillin-resistant (MRSA) strains and, optimally, ABE should be treated with bactericidal antibiotics. Traditionally, vancomycin has long been used to treat MRSA ABE, but it has been shown that vancomycin may increase the staphylococcal the thickness, resulting in permeability-mediated resistance. We present a case of a 72-year-old male with mitral valve MRSA ABE refractory to daptomycin therapy following initial therapy with vancomycin. We were not able to diminish the intensity of the patient's MRSA bacteremia from his mitral valve ABE, even with high-dose (12 mg/kg day) daptomycin, presumably because of permeability-mediated resistance due to antecedent vancomycin therapy.

A randomized controlled trial of vitamin D3 supplementation for the prevention of symptomatic upper respiratory tract infections.

Vitamin D has been shown to be an important immune system regulator. Vitamin D insufficiency during winter may cause increased susceptibility to upper respiratory tract infections (URIs). To determine whether vitamin D supplementation during the winter season prevents or decreases URI symptoms, 162 adults were randomized to receive 50 microg vitamin D3 (2000 IU) daily or matching placebo for 12 weeks. A bi-weekly questionnaire was used to record the incidence and severity of URI symptoms. There was no difference in the incidence of URIs between the vitamin D and placebo groups (48 URIs vs. 50 URIs, respectively, P=0.57). There was no difference in the duration or severity of URI symptoms between the vitamin D and placebo groups [5.4+/-4.8 days vs. 5.3+/-3.1 days, respectively, P=0.86 (95% CI for the difference in duration -1.8 to 2.1)]. The mean 25-hydroxyvitamin D level at baseline was similar in both groups (64.3+/-25.4 nmol/l in the vitamin D group; 63.0+/-25.8 nmol/l in the placebo group; n.s.). After 12 weeks, 25-hydroxyvitamin D levels increased significantly to 88.5+/-23.2 nmol/l in the vitamin D group, whereas there was no change in vitamin D levels in the placebo group. There was no benefit of vitamin D3 supplementation in decreasing the incidence or severity of symptomatic URIs during winter. Further studies are needed to determine the role of vitamin D in infection.

Metronidazole single versus multiple daily dosing in serious intraabdominal/pelvic and diabetic foot infections.

The purpose of the study was to compare the clinical efficacy of once-daily versus multiple dose regimens of metronidazole in inpatients with serious/systemic Bacteroides fragilis infections, i.e., intraabdominal/pelvic and diabetic foot infections. A retrospective chart review was performed on 145 adult inpatients who received combination therapy with metronidazole for B. fragilis abdominal/pelvic infection or diabetic (deep) foot infections/osteomyelitis. Exclusion criteria included metronidazole given for indications other than those mentioned, patients who received only one dose of metronidazole, and patients who received oral metronidazole only. The 145 patients were in two groups: 66 patients in the metronidazole 1 g (i.v.) q24h (Group A) and 79 patients who received metronidazole 500 mg (i.v./p.o.) q6-8h dosing (Group B). Patient demographics included age, gender, indications of metronidazole, concomitant, antibiotics, and co-morbidities. Data collection also included length of stay (LOS), antibiotic days, and clinical outcomes. The 145 patients in our study had a mean age of 66 years, 61% were female and 39% male. Most patients were being treated for definitive intraabdominal/pelvic infections (82%), or probable intraabdominal/pelvic infections (22%). Only 6% had deep diabetic foot infections of osteomyelitis (percentages exceed 100% since a patient can have more than one indication) and were included since B. fragilis is also and important pathogen in diabetic osteomyelitis. Group A patients had more concomitant antibiotics and co-morbidities (p < 0.0001 and p < 0.05 respectively, chi-square test for trend) than Group B patients. There were no statistically significant differences between groups A and B for LOS and antibiotic days (p = 0.42 and p = 0.92 respectively, by rank-sum test), but after adjusting for concomitant antibiotics and co-morbidities Group A patients had clinically shorter LOS and fewer antibiotic days. Unadjusted mortality and failure rates were non-significantly higher in group A (relative ratios of 12.1%/6.3% = 6.3% = 1.91 and 18.2%/ 10.1% = 1.80 respectively), but after adjusting for concomitant antibiotics and co-morbidities with stratification analysis, groups A and B were virtually the same (risk differences of

Viral influenza-like illnesses: dynamic interrelationships during the 2015-2016 influenza season in hospitalized patients.

In hospitalized children and adults, the temporal relationship of viruses causing influenza-like illnesses (ILIs) and influenza has not been well described. During the 2015-2016 influenza season at our hospital, the dynamic interrelationships between ILI viruses (human metapneumovirus, respiratory syncytial virus, human parainfluenza viruses 3 and 4, rhinoviruses/enteroviruses, and coronaviruses) and influenza A were characterized in 768 hospitalized children and adults.

The atypical pneumonias: clinical diagnosis and importance.

The most common atypical pneumonias are caused by three zoonotic pathogens, Chlamydia psittaci (psittacosis), Francisella tularensis (tularemia), and Coxiella burnetii (Q fever), and three nonzoonotic pathogens, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella. These atypical agents, unlike the typical pathogens, often cause extrapulmonary manifestations. Atypical CAPs are systemic infectious diseases with a pulmonary component and may be differentiated clinically from typical CAPs by the pattern of extrapulmonary organ involvement which is characteristic for each atypical CAP. Zoonotic pneumonias may be eliminated from diagnostic consideration with a negative contact history. The commonest clinical problem is to differentiate legionnaire's disease from typical CAP as well as from C. pneumoniae or M. pneumonia infection. Legionella is the most important atypical pathogen in terms of severity. It may be clinically differentiated from typical CAP and other atypical pathogens by the use of a weighted point system of syndromic diagnosis based on the characteristic pattern of extrapulmonary features. Because legionnaire's disease often presents as severe CAP, a presumptive diagnosis of Legionella should prompt specific testing and empirical anti-Legionella therapy such as the Winthrop-University Hospital Infectious Disease Division's weighted point score system. Most atypical pathogens are difficult or dangerous to isolate and a definitive laboratory diagnosis is usually based on indirect, i.e., direct flourescent antibody (DFA), indirect flourescent antibody (IFA). Atypical CAP is virtually always monomicrobial; increased IFA IgG tests indicate past exposure and not concurrent infection. Anti-Legionella antibiotics include macrolides, doxycycline, rifampin, quinolones, and telithromycin. The drugs with the highest level of anti-Legionella activity are quinolones and telithromycin. Therapy is usually continued for 2 weeks if potent anti-Legionella drugs are used. In adults, M. pneumoniae and C. pneumoniae may exacerbate or cause asthma. The importance of the atypical pneumonias is not related to their frequency (approximately 15% of CAPs), but to difficulties in their diagnosis, and their nonresponsiveness to beta-lactam therapy. Because of the potential role of C. pneumoniae in coronary artery disease and multiple sclerosis (MS), and the role of M. pneumoniae and C. pneumoniae in causing or exacerbating asthma, atypical CAPs also have public health importance.

Appropriateness of empiric gentamicin and vancomycin therapy for bacteremias in chronic dialysis outpatient units in the era of antibiotic resistance.

Bacteremias in inpatient chronic HD units have been described, but there is little information on bacteremias in ambulatory HD units. To determine the frequency of bacteremia and pathogen distribution in ambulatory chronic HD units, we retrospectively reviewed our experience with 107 bacteremias in 5 chronic ambulatory HD units over a 3 year period. The object of the study was twofold. The first objective was to determine if bacteremias in ambulatory HD setting were substantially different in frequency or type than in the inpatient HD setting. Secondly, febrile patients suspected of having bacteremia in chronic HD patients are often empirically treated with vancomycin and gentamicin. Chronic HD patients require repeated and frequent venous access for HD. Bacteremias are common in chronic HD patients and may be primary or secondary and are often related to venous access site infections. The distributions of bacteremia pathogens in chronic HD patients are predominantly reflective of skin flora, i.e., staphylococci and to lesser extent aerobic Gram-negative bacilli. After S. aureus (MSRA/MSSA) and coagulase-negative staphylococcus (CoNS), enterococci are the next most important Gram-positive pathogens in bacteremic HD patients. Most strains of E. faecalis are sensitive to vancomycin and for practical purposes should be considered as vancomycin sensitive enterococci (VSE). In contrast, most strains of E. faecium are resistant to vancomycin and should be considered as vancomycin resistant enterococci (VRE). We retrospectively reviewed 107 patients on chronic ambulatory HD to determine the adequacy of empiric vancomycin and gentamicin prophylaxis. We found amikacin is preferred to gentamicin and that meropenem is an effective alternate substitution for gentamicin and vancomycin combination therapy.

Methicillin-resistant Staphylococcus aureus: clinical manifestations and antimicrobial therapy.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common skin coloniser and less commonly causes infection. MRSA colonisation should be contained by infection control measures and not treated. MRSA infections cause the same spectrum of infection as MSSA infections, i.e., skin/soft tissue infections, bone/joint infections, central IV line infections, and acute bacterial endocarditis (native valve/prosthetic valve). There is a discrepancy between in-vitro sensitivity and in-vivo effectiveness with MRSA. To treat MRSA infections, clinicians should select an MRSA drug with proven in-vivo effectiveness, i.e., daptomycin. Linezolid, quinupristin/dalfopristin, minocycline, or vancomycin, and not rely on in-vitro susceptibility data. For MRSA, doxycycline cannot be substituted for minocycline. Linezolid and minocycline are available for oral administration and both are also effective in treating MRSA CNS infections. Vancomycin is being used less due to side effects, (increasing MICs/resistance, VISA/VRSA), and increased VRE prevalence. The most potent anti-MRSA drug at the present time is daptomycin. Daptomycin is useful when rapid/effective therapy of MRSA bacteraemia/endocarditis is necessary. Daptomycin is also useful to treat persistent MRSA bacteraemias/MRSA treatment failures with other drugs, i.e., vancomycin. There is no difference in virulence between MSSA and MRSA infections if treatment is started early and with an agent that has in-vivo effectiveness.