Dominick Cavuoti

Management and outcome of children with skin and soft tissue abscesses caused by community-acquired methicillin-resistant Staphylococcus aureus.

Background. Although the epidemiology of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been explored in many investigations, management of this emerging infection has not been well-studied. For non-methicillin-resistant Staphylococcus aureus skin and soft tissue abscesses, incision and drainage is generally adequate therapy without the use of antibiotics, but this has not been established for CA-MRSA. Methods. Children presenting to Children’s Medical Center of Dallas for management of skin and soft tissue abscesses caused by culture-proved CA-MRSA were prospectively followed. We analyzed data from the initial evaluation and from two follow-up visits that focused on the management and outcome of CA-MRSA infection. Retrospective chart review was performed 2 to 6 months after the initial visit. Results. Sixty-nine children were identified with culture-proved CA-MRSA skin and soft tissue abscess. Treatment consisted of drainage in 96% of patients and wound packing in 65%. All children were treated with antibiotics. Five patients (7%) were prescribed an antibiotic to which their CA-MRSA isolate was susceptible before culture results were known. Four patients (6%) required hospital admission on the first follow-up; none of these patients had received an antibiotic effective against CA-MRSA. A significant predictor of hospitalization was having a lesion initially >5 cm (P = 0.004). Initial ineffective antibiotic therapy was not a significant predictor of hospitalization (P = 1.0). Of the 58 patients initially given an ineffective antibiotic and managed as outpatients, an antibiotic active against CA-MRSA was given to 21 (36%) patients after results of cultures were known. No significant differences in response were observed in those who never received an effective antibiotic than in those who did. Conclusions. Incision and drainage without adjunctive antibiotic therapy was effective management of CA-MRSA skin and soft tissue abscesses with a diameter of <5 cm in immunocompetent children.

Changing trends in acute osteomyelitis in children: impact of methicillin-resistant Staphylococcus aureus infections.

Background: Staphylococcus aureus remains the most common etiologic agent of acute osteomyelitis in children. Recently, methicillin-resistant S. aureus (MRSA) has emerged as a major pathogen. Methods: Records of all children admitted with acute osteomyelitis from January 1999 to December 2003 were reviewed. For the comparative analysis, the study population was evenly distributed in 2 periods: period A, January 1999 to June 2001; n = 113; and period B, July 2001 to December 2003; n = 177. In addition, clinical findings of MRSA osteomyelitis were compared with non-MRSA osteomyelitis, including methicillin-sensitive S. aureus infections. Results: Two hundred ninety children (60% male subjects) with acute osteomyelitis were identified. Median (25th-75th percentile) age at diagnosis was 6 years (range, 2-11 years). Significant clinical findings included the following: localized pain (84%), fever (67%), and swelling (62%). Affected bones included the following: foot (23%), femur (20%), tibia (16%), and pelvis (7%). Thirty-seven percent of blood cultures were positive, and a bacterial isolate was obtained in 55% of cases. Bacteria most frequently isolated included the following: methicillin-sensitive S. aureus (45%) (57% in period Avs 40% in period B), MRSA (23%) (6% in A vs 31% in B; P < 0.001), Streptococcus pyogenes (6%), and Pseudomonas aeruginosa (5%). Children with MRSA compared with those with non-MRSA osteomyelitis had significantly greater erythrocyte sedimentation rate and C-reactive protein values on admission and increased length of hospital stay, antibiotic therapy, and overall rate of complications. We observed significant changes in antibiotic therapy related to increased use of agents with activity against MRSA. Conclusions: Methicillin-resistant S. aureus was isolated more frequently in the second study period and was associated with worse clinical outcomes. Level of Evidence: II. Retrospective study.

Inducible Clindamycin Resistance and Molecular Epidemiologic Trends of Pediatric Community-Acquired Methicillin-Resistant Staphylococcus aureus in Dallas, Texas

ABSTRACT Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection occurs commonly in children. Clindamycin resistance may be inducible or constitutive, and the rates of inducible resistance in CA-MRSA that could produce clindamycin treatment failures vary worldwide. The double-disk test was performed in 197 erythromycin-resistant and clindamycin-susceptible CA-MRSA strains from children in Dallas, Texas, from 1999 to 2002 to determine inducible clindamycin resistance. Resistance mechanisms were studied by PCR; epidemiologic trends were studied by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Inducible resistance was demonstrated in 28 (93% ±6%) of 30 tested isolates in 1999, 21 (64%, ±11%) of 33 in 2000, 12 (23% ±7%) of 52 in 2001, and 6 (7% ±3%) of 82 in 2002. All noninducible strains had the msr(A) gene. Among inducible resistant strains, 31 had erm(B), 24 had erm(C), and 12 had erm(A) genes. Two distinct pulsed types were the most prevalent; one of them was the most common pulsed type in 1999, whereas in 2002 a different pulsed type was prevalent. MLST analyses determined that ST-8 was the most common type, with 76% ±5% found in 2002. All but one of these clindamycin-susceptible, erythromycin-resistant ST-8 strains showed no induction of clindamycin resistance. We conclude that, among erythromycin-resistant, clindamycin-susceptible CA-MRSA strains isolated from children in Dallas, inducible methylase resistance became less common from 1999 to 2002 (P < 0.001). The phenotype of strains was associated with their sequence type. Our results demonstrate a clonal shift in CA-MRSA in Dallas children from 1999 to 2002.

Pneumonia and Septicemia Caused by Burkholderia thailandensis in the United States

ABSTRACT Burkholderia thailandensis is closely related to Burkholderia pseudomallei, the causative agent of melioidosis. It is generally considered avirulent and previously has been reported to occur only in Southeast Asia. We report the first case of pneumonia and septicemia caused by B. thailandensis in the United States.

Fatal Outcomes in Family Transmission of Mycoplasma pneumoniae

BACKGROUND Mycoplasma pneumoniae continues to be a significant cause of community-acquired pneumonia and, on rare occasions, manifests as fulminant disease that leads to mortality, even in healthy individuals. METHODS We conducted a retrospective study on members of a family who were quarantined by the Centers for Disease Control and Prevention in 2002 for respiratory failure and death of a 15-year-old brother (sibling 1) and a 13-year-old sister (sibling 2). Collected airway, cerebrospinal fluid (CSF), and serum samples from both deceased siblings and serum samples from both parents and the remaining 3 ill siblings (sibling 3-5) were tested using a range of diagnostic assays. Autopsy lung tissue samples from sibling 2 were also assessed using immunohistochemical and immunoelectron microscopic methods. RESULTS Autopsy evaluation of sibling 1 revealed cerebral edema consistent with hypoxic ischemic encepatholopathy and pulmonary findings of bronchiolitis obliterans with organizing pneumonia (BOOP). Postmortem lung examination of sibling 2 revealed lymphoplasmacytic bronchiolitis with intraluminal purulent exudate, BOOP, and pulmonary edema. Results of diagnostic assays implicated the household transmission of M. pneumoniae among all 5 siblings and both parents. Further analysis of lung tissue from sibling 2 demonstrated the presence of M. pneumoniae organisms and community-acquired respiratory distress syndrome toxin. M. pneumoniae was cultured directly from sibling 2 autopsy lung tissue. CONCLUSION Evidence is provided that M. pneumoniae was readily transmitted to all members of the household and that the resulting infections led to a spectrum of individual responses with variation in disease progression, including lymphoplasmacytic bronchiolitis, BOOP, and death.

Fatal Salmonella aortitis with mycotic aneurysm rupture

Salmonellae most commonly cause uncomplicated cases of gastroenteritis but have a predilection for damaged blood vessels, especially those damaged by atherosclerosis. The abdominal aorta is most frequently affected. The most serious complication of Salmonella aortitis is mycotic aneurysm formation with subsequent rupture. The authors present the case of a 61-year-old man who was found unresponsive at home 3 days after discharge from the hospital for treatment of Salmonella gastroenteritis with bacteremia. Postmortem examination revealed a ruptured mycotic aneurysm with a large retroperitoneal hematoma. Numerous gram-negative rods were embedded in the wall of the aorta and surrounding inflammatory infiltrate, compatible with the patient’s previously isolated Salmonella. Whereas abdominal aortic aneurysm rupture is most commonly associated with atherosclerosis, the isolation of Salmonella from blood cultures, coupled with radiographic evidence of gas surrounding the aorta, should raise the suspicion of infectious aortitis. Whereas fatal rupture of an aortic aneurysm secondary to atherosclerosis alone or in conjunction with Salmonella aortitis will not have an impact on the manner of death, Salmonella infections are reportable and thus have public health implications.

Splenic abscess with Vibrio cholerae masking pancreatic cancer

A 77-year-old man presented to our hospital with a clinical scenario suspicious for endocarditis with septic emboli to the lungs and splenic abscess. Vibrio cholerae was isolated from purulent material aspirated from the abscess. Medical therapy and percutaneous drainage of the abscess were unsuccessful. The patient underwent splenectomy and distal pancreatectomy revealing a pancreatic tail carcinoma involving the spleen and colon. The patient later expired secondary to metastatic disease. This case represents the first isolation of V. cholerae from a splenic abscess but also illustrates that although newer imaging technologies have made the diagnosis of splenic abscess easier, the true etiology of the abscess may remain elusive.

Clear cell carcinoma in a background of endometriosis. Case report of a finding in a midline abdominal scar 5 years after a total abdominal hysterectomy.

BACKGROUND Endometriosis is considered a premalignant process whose association with carcinoma is well documented. We discuss a case of clear cell carcinoma with an unusual presentation in that it was located outside the abdominal cavity and was the only lesion noted clinically and radiologically. The histopathologic diagnostic criteria will be reviewed, as will the association of carcinomas with endometriosis. Furthermore, we will review the current literature of extraovarian clear cell carcinoma associated with endometriosis with regard to clinical outcome. CASE A 42-year-old Hispanic woman presented to the Fine Needle Aspiration (FNA) Clinic at Parkland Hospital, Dallas, Texas, in August 2005 secondary to a growing area of firmness associated with her midline abdominal hysterectomy scar. A single mass anterior to the abdominal wall was identified radiologically. The FNA sample was reported as highly atypical cells suspicious for adenocarcinoma. Excision of this mass revealed a clear cell carcinoma in a background of endometriosis. CONCLUSION Clear cell carcinoma is one of the most prevalent carcinomas associated with endometriosis, whether identified in the ovary or extraovarian site. This case is perplexing because the mass was a solitary lesion and the patient never had documented endometriosis. The unusual presentation may make survival difficult to predict.

Interpretation of positive molecular tests of common viruses in the cerebrospinal fluid.

Many central nervous system infections are historically difficult to diagnose. Polymerase chain reaction (PCR) has revolutionized the diagnosis of these infections because of their high sensitivity despite the lack of data on clinical usefulness. We conducted a retrospective study that included patients with positive cerebrospinal fluid (CSF) PCR for herpes simplex virus, varicella-zoster virus, JC virus, cytomegalovirus (CMV), and Epstein-Barr virus (EBV) between January 2009 and December 2011. The positive results were grouped into definite, likely, and possible true positives and likely false-positive categories based on pre-specified definitions specific to each virus. Of 1663 CSF viral PCR tests, 88 were positive (5%). The combined positive predictive value (PPV) was 58%. The PPVs were least for CMV and EBV at 29 and 37%, respectively. A positive CSF viral PCR result has to be interpreted with caution due to several false-positive results.

Cytologic Diagnosis of Blastocystis hominis in Peritoneal Fluid : A Case Report

BACKGROUND Blastocystis hominis is the most common parasite identified in s worldwide. Although it is commonly identified in stool preparations, unusual to encounter B hominis in abdominal fluid. CASE A 46-year-old woman presented with the clinical impression of acute peritonitis. The initial radiologic evaluation showed free air in the abdominal cavity and an abdominal mass. Abdominal fluid submitted for cytologic examination was diagnostic of acute inflammation with mixed bacteria and abundant cystlike forms of B hominis. The patient underwent an exploratory laparotomy that revealed a poorly differentiated adenocarcinoma involving her bowel and peritoneum. CONCLUSION The present case highlights the unusual identification ofextraintestinal forms of B hominis in a peritoneal fluid sample from a patient with invasive, poorly differentiated adenocarcinoma and associated bowel perforation.