Length of exposure to the hospital environment is more important than antibiotic exposure in healthcare associated infections by methicillin-resistant Staphylococcus aureus: a comparative study

OBJECTIVES: Both total antimicrobial use and specific antimicrobials have been implicated as risk factors for healthcare-associated methicillin-resistant Staphylococcus aureus (HCA-MRSA) infection. The aims of this study were: (I) to explore predictors of a new HCA-MRSA infection in comparison with a new healthcare-associated methicillin-sensitive Staphylococcus aureus (HCA-MSSA); (II) to thoroughly assess the role of recent antibiotic use qualitatively and quantitatively. METHODS: The time-period for our study was from October 1997 through September 2001. Through applying strict criteria, we identified two groups of inpatients, one with a new HCA-MRSA infection and one with a new HCA-MSSA infection. We recorded demographic, clinical and antibiotic use-related data up to 30 days before the positive culture date. RESULTS: We identified 127 and 70 patients for each group, respectively. Two logistic regression models were carried out to assess the role of antimicrobial use (qualitatively and quantitatively). In model I, duration of hospital stay, presence of chronic wounds, aminoglycoside and fluoroquinolone use retained statistical significance. In model II, duration of hospital stay and history of intubation during the last month stood out as the only significant predictors of a subsequent HCA-MRSA infection. No significant differences in outcome were noted. CONCLUSIONS: The length of exposure to the hospital environment may be the best predictor of a new HCA-MRSA infection. Use of aminoglycosides and fluoroquinolones may also stand independently along with presence of chronic ulcers and surgical procedures. No independent association between quantitative antibiotic use and subsequent HCA-MRSA infection was documented.

Robust and sensitive high-performance liquid chromatographic-UV detection technique for the determination of tigecycline in rabbit plasma.

An isocratic HPLC method with detection at 248 nm was developed and fully validated for the determination of tigecycline in rabbit plasma. Minocycline was used as an internal standard. A Hypersil BDS RP-C18 column (250 x 4.6 mm, 5 microm particle size) was used with the mobile phase phosphate buffer (pH 7.10, 0.070 M)-acetonitrile (76 + 24, v/v) at a flow rate of 1.0 mL/min. The elution time of tigecycline and minocycline was approximately 8.1 and 9.9 min, respectively. Calibration curves of tigecycline were linear in the concentration range of 0.021-3.15 microg/mL in plasma. The LOD and LOQ in plasma were estimated as 7 and 21 ng/mL, respectively. The intraday and interday precision values of the method were in the range of 5.0-7.1 and 5.6-9.1%, while the corresponding accuracy values were in the ranges of 92.8-111.1 and 97.6-102.3%, respectively. At the LOQ, the intraday precision was 18.7%, while intraday and interday accuracy values were 97.3 and 98.0%, respectively. Robustness of the proposed method was studied using a Plackett-Burman experimental design. A pharmacokinetic profile is presented for confirmation of the applicability of the method to pharmacokinetic studies.

Length of exposure to the hospital environment is more important than antibiotic exposure in healthcare associated infections by methicillin-resistant Staphylococcus aureus: a comparative study.

OBJECTIVES: Both total antimicrobial use and specific antimicrobials have been implicated as risk factors for healthcare-associated methicillin-resistant Staphylococcus aureus (HCA-MRSA) infection. The aims of this study were: (I) to explore predictors of a new HCA-MRSA infection in comparison with a new healthcare-associated methicillin-sensitive Staphylococcus aureus (HCA-MSSA); (II) to thoroughly assess the role of recent antibiotic use qualitatively and quantitatively. METHODS: The time-period for our study was from October 1997 through September 2001. Through applying strict criteria, we identified two groups of inpatients, one with a new HCA-MRSA infection and one with a new HCA-MSSA infection. We recorded demographic, clinical and antibiotic use-related data up to 30 days before the positive culture date. RESULTS: We identified 127 and 70 patients for each group, respectively. Two logistic regression models were carried out to assess the role of antimicrobial use (qualitatively and quantitatively). In model I, duration of hospital stay, presence of chronic wounds, aminoglycoside and fluoroquinolone use retained statistical significance. In model II, duration of hospital stay and history of intubation during the last month stood out as the only significant predictors of a subsequent HCA-MRSA infection. No significant differences in outcome were noted. CONCLUSIONS: The length of exposure to the hospital environment may be the best predictor of a new HCA-MRSA infection. Use of aminoglycosides and fluoroquinolones may also stand independently along with presence of chronic ulcers and surgical procedures. No independent association between quantitative antibiotic use and subsequent HCA-MRSA infection was documented.

An outbreak of hemodialysis catheter-related bacteremia with sepsis caused by Streptococcus agalactiae in a hemodialysis unit.

BACKGROUND: Rates of invasive group B Streptococcus (GBS; Streptococcus agalactiae) disease in adults are on the rise. Invasive GBS disease can be community- or healthcare-associated. We report an outbreak of GBS catheter-related bacteremia in a hemodialysis (HD) unit. MATERIALS AND METHODS: Two patients undergoing HD at the same outpatient HD unit were admitted on the same day (within a few hours of each other) with catheter-related GBS bacteremia. A retrospective study was undertaken at the HD unit to address risk factors for febrile illness on the last HD session day. A detailed questionnaire was completed by all HD patients treated on the same day as the two GBS patients and by all members of the nursing and medical staff. Medical and nursing records of the HD unit were reviewed, as well as infection control and catheter care practices. Patients and staff members submitted swabs for culture. RESULTS: No rectal or vaginal culture of any HD patient or staff member was positive for GBS. The development of recent febrile disease was significantly associated with the presence of a hemodialysis catheter (p=0.028) and care for more than 30min by a specific nurse during the last two HD sessions (p=0.007). CONCLUSIONS: We speculate that the GBS strain was transmitted from one patient to the other through the hands of medical personnel. No such outbreak has ever been reported in HD patients. The importance of strict infection control practices in HD units and the avoidance of catheters for long-term HD should be emphasized.

Long-term complete regression of nodal marginal zone lymphoma transformed into diffuse large B-cell lymphoma with highly active antiretroviral therapy alone in human immunodeficiency virus infection.

Since the introduction of combination antiretroviral therapy (cART), there has been a decrease in the incidence of non-Hodgkin lymphoma among the HIV-infected population and also significantly improved survival rates. We describe a remarkable case of a HIV-infected patient whose large B-cell lymphoma, most likely arising by transformation of a nodal marginal zone lymphoma, completely regressed with the use of cART alone. He remained disease-free for almost 3 years and he finally died from presumed flare up of his lymphoma. There are very few cases of spontaneous regression of lymphomas with cART alone in the HIV population. This is an extreme example of the significance of cART in improving survival in HIV-non-Hodgkin lymphoma and changing the face of the HIV epidemic in general.

Fatal rhizopus pneumonia in allogeneic stem cell transplant patients despite posaconazole prophylaxis: two cases and review of the literature.

Posaconazole is a triazole with broad spectrum of activity against multiple fungi including members of the fungal order Mucorales. This activity has been shown both in clinical and in vitro studies, which are critically reviewed here. It has become very popular in prophylaxis in acute myelogenous leukemia (AML) induction and in the graft-versus-host disease (GVHD) settings after 2 recent prospective trials that showed advantage of posaconazole prophylaxis compared to fluconazole or itraconazole. In this report, 2 patients are presented, in whom, despite posaconazole prophylaxis, invasive and ultimately fatal Rhizopus pulmonary infections developed. These cases are similar to a previously reported case of Rhizopus infection in a stem cell transplant recipient who also received posaconazole, indicating a potential newly recognized pattern of breakthrough infections in patients receiving posaconazole prophylaxis.

Community-acquired methicillin-resistant Staphylococcus aureus as a cause of rapidly progressing pyelonephritis with pyonephrosis, necessitating emergent nephrectomy.

In this article, we describe the first, to our knowledge, reported case of severe bacteremic upper urinary tract infection with pyonephrosis-in the context of prior chronic urinary tract disease-caused by community-acquired methicillin-resistant Staphylococcus aureus (MRSA). The patient presented with fever and constitutional symptoms, and computed tomography revealed extensive renal parenchymal infection along with a staghorn calculus and dilatation of the pyelocalyceal system. His clinical condition rapidly deteriorated, and he developed uncontrollable sepsis, necessitating an emergent nephrectomy. Significant pyonephrosis was noted during surgery. Blood cultures yielded MRSA, and molecular analysis (by polymerase chain reaction) of the MRSA strains from blood and wound fluid showed that they were Panton-Valentine leukocidin positive and they also possessed SCCmecA type IV. Postoperatively, the patient was treated with intravenous vancomycin for 3 weeks and had a favorable outcome.

Primary sternal osteomyelitis caused by Nocardia nova: case report and literature review.

A 51 year old woman without significant past medical history or risk factors for Nocardia infection developed primary Nocardia nova sternal osteomyelitis with mediastinal abscess, diagnosed with open biopsy. She required prolonged antibiotic therapy and had a favorable outcome. Primary sternal osteomyelitis develops in the absence of a contiguous focus of infection, as opposed to secondary sternal osteomyelitis, which is usually a complication of sternotomy. Staphylococcus aureus probably still is the most common cause of both forms of sternal osteomyelitis. Nocardia species invade humans usually through the respiratory tract and can cause a variety of localized infections through the hematogenous route. Pulmonary involvement may or may not coexist. Immunosuppressed patients are more prone to infection by Nocardia species, although cases involving seemingly immunocompetent patients are not rare. This is the first reported case in the English literature of primary sternal osteomyelitis due to Nocardia nova or any other Nocardia species.

Primary sternal osteomyelitis caused by Nocardia nova: case report and literature review

A 51 year old woman without significant past medical history or risk factors for Nocardia infection developed primary Nocardia nova sternal osteomyelitis with mediastinal abscess, diagnosed with open biopsy. She required prolonged antibiotic therapy and had a favorable outcome. Primary sternal osteomyelitis develops in the absence of a contiguous focus of infection, as opposed to secondary sternal osteomyelitis, which is usually a complication of sternotomy. Staphylococcus aureus probably still is the most common cause of both forms of sternal osteomyelitis. Nocardia species invade humans usually through the respiratory tract and can cause a variety of localized infections through the hematogenous route. Pulmonary involvement may or may not coexist. Immunosuppressed patients are more prone to infection by Nocardia species, although cases involving seemingly immunocompetent patients are not rare. This is the first reported case in the English literature of primary sternal osteomyelitis due to Nocardia nova or any other Nocardia species.

First-time use of bevacizumab for aggressive, metastatic hepatocellular carcinoma in an HIV/hepatitis B virus coinfected patient: a case report.

We present a case of an HIV-1 infected patient with history of chronic hepatitis B and chronic alcohol use without cirrhosis, who presented with aggressive hepatocellular carcinoma with multiple metastases. Systemic chemotherapy combined with use of bevacizumab (anti-vascular endothelium growth factor monoclonal antibody) was without effect and the patient succumbed to his disease within few weeks. To our knowledge, this is the first report in the English literature of bevacizumab use for metastatic hepatocellular carcinoma in HIV-infected patients.

Revertant multiresistant HIV in chronically infected drug naïve patients: when baseline resistance testing is not enough.

We present a patient with chronic HIV-1 infection and primary multi-drug resistance, the magnitude of which was underestimated by the baseline genotypic resistance testing (GRT) due to reversion of some of the mutations of the transmitted strain. This resulted in complete failure of his first antiretroviral regimen with rapid appearance of presumably archived mutations to more than one antiretroviral classes. Interestingly, his viral load remained high even in the presence of the M184V mutation. Baseline GRT in chronic HIV infection may not give adequate information in the presence of acquired multi-drug-resistant HIV strains, which have one or more of their mutations reverted. The presence of 215 codon polymorphisms should alert physicians to the possible coexistence of archived nucleoside and non-nucleoside reverse transcriptase inhibitor mutations. In such a case, initiation of a regimen with a low genetic barrier to resistance may not be the best choice and, if done, should be done cautiously and with more frequent monitoring of treatment response than usual.