Tetracycline and trimethoprim/sulfamethoxazole at clinical laboratory: can they help to characterize Staphylococcus aureus carrying different SCCmec types?

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) can be difficult to detect at the clinical practice. METHODS: We analyzed 140 MRSA isolates from inpatients to correlate the antimicrobial susceptibility with the SCCmec types. RESULTS: Type III (n = 63) isolates were more resistant to ciprofloxacin, clindamycin, cloramphenicol, erythromycin, gentamicin, and rifampin than type IV (n = 65) ones (p < 0.05). Moreover, type IV isolates were susceptible to tetracycline (100%) and trimethoprim/sulfamethoxazole (98%), while type III isolates presented resistance to them. CONCLUSIONS: In regions where these SCCmec types are prevalent, the detection of specific resistant phenotypes could help to predict them, mainly when there are no technical conditions to SCCmec typing.

Emergence of clonal complex 5 (CC5) methicillin-resistant Staphylococcus aureus (MRSA) isolates susceptible to trimethoprim-sulfamethoxazole in a Brazilian hospital

In this study, genotyping techniques including staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and restriction-modification tests were used to compare the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered at two times within a 10-year interval (1998 and 2008) from a tertiary Brazilian hospital. In addition, the antimicrobial susceptibility profiles were analyzed. All 48 MRSA isolates from 1998 and 85.7% from 2008 (48/56 isolates) displayed multidrug-resistance phenotypes and SCCmec III. All but one of the 13 representative SCCmec III isolates belonged to CC8 and had PFGE patterns similar to that of the BMB9393 strain (Brazilian epidemic clone of MRSA; BEC). In 2008, we found an increased susceptibility to rifampicin and chloramphenicol among the SCCmec III isolates. In addition, we detected the entrance of diverse international MRSA lineages susceptible to trimethoprim-sulfamethoxazole (SXT), almost all belonging to CC5. These non-SCCmec III isolates were related to the USA 300 (ST8-SCCmec IV; PFGE-type B), USA 800 (ST5-SCCmec IV; subtype D1), USA 100 (ST5-SCCmec II; subtype D2), and EMRSA-3/Cordobes (ST5-SCCmec I, type C) clones. To the best of our knowledge, this is the first report of the emergence of isolates genetically related to the EMRSA-3/Cordobes clone in southeast Brazil. In this regard, these isolates were the most common non-SCCmec III MRSA in our institution, accounting for 8.9% of all isolates recovered in 2008. Thus, despite the supremacy of BEC isolates in our country, significant changes may occur in local MRSA epidemiology, with possible consequences for the rationality of MRSA empiric therapy.

Disseminated nocardiosis due to Nocardia farcinica: diagnosis by thyroid abscess culture

A previously healthy 75-year-old white male dentist presented with a 6-month history of low-back pain treated with chronic steroid therapy had a Nocardia farcinica infection diagnosed by aspirate of thyroid abscess and six blood cultures. Despite the treatment with parenteral combination of trimethoprim/sulfamethoxazole, the patient failed to respond and died after two days of therapy. Autopsy revealed disseminated nocardiosis, involving lungs with pleural purulent exudate in both sides, heart, thyroid, kidneys, brain, bones, and lumbosacral soft tissue with destruction of L2-L4.

Whipple's disease: rare disorder and late diagnosis

Whipple's disease is a rare systemic infectious disorder caused by the bacterium Tropheryma whipplei. We report the case of a 61-year-old male patient who presented to emergency room complaining of asthenia, arthralgia, anorexia, articular complaints intermittent diarrhea, and a 10-kg weight loss in one year. Laboratory tests showed the following results: Hb = 7.5 g/dL, albumin = 2.5 mg/dL, weight = 50.3 kg (BMI 17.4 kg/m²). Upper gastrointestinal endoscopy revealed areas of focal enanthema in the duodenum. An endoscopic biopsy was suggestive of Whipple's disease. Diagnosis was confirmed based on a positive serum polymerase chain reaction. Treatment was initiated with intravenous ceftriaxone followed by oral trimethoprim-sulfamethoxazole. After one year of treatment, the patient was asymptomatic, with Hb = 13.5 g/dL, serum albumin = 5.3 mg/dL, and weight = 70 kg (BMI 24.2 kg/m²). Whipple's disease should be considered a differential diagnosis in patients with prolonged constitutional and/or gastrointestinal symptoms. Appropriate antibiotic treatment improves the quality of life of patients.

USE OF LOPINAVIR/RITONAVIR ASSOCIATED WITH ERGOTAMINE RESULTING IN FOOT AMPUTATION: BRIEF COMMUNICATION

A 32-year-old female, was diagnosed in 2004 with a C1 HIV1 infection, using zidovudine/lamivudine 300/150 mg BID and lopinavir/ritonavir 400/100 mg BID, in addition to prophylaxis with trimethoprim-sulfamethoxazole 800/160 mg QD, but no prophylaxis with macrolide antibiotics. The patient presented with a severe headache and was prescribed two capsules of the anti-migraine drug Ormigrein™, which contained ergotamine tartrate 1 mg, caffeine 100 mg, paracetamol 220 mg, hyoscyamine sulfate 87.5 mcg, and atropine sulfate 12.5 mcg. Afterwards she was prescribed one capsule of Ormigrein every 30 minutes for a total of six capsules a day. The patient took the medication as prescribed but developed a pain in her left ankle three days later, which evolved to the need for amputation.

SUSCEPTIBILITY TO ANTIBIOTICS IN URINARY TRACT INFECTIONS IN A SECONDARY CARE SETTING FROM 2005-2006 AND 2010-2011, IN SÃO PAULO, BRAZIL: DATA FROM 11,943 URINE CULTURES

Introduction: Urinary tract infection (UTI) has a high incidence and recurrence, therefore, treatment is empirical in the majority of cases. Objectives: The aim of this study was to analyze the urine cultures performed at a secondary hospital, during two periods, 2005-2006 and 2010-2011, and to estimate the microbial resistance. Patients and methods: We analyzed 11,943 aerobic urine cultures according to basic demographic data and susceptibility to antibiotics in accordance with the Clinical and Laboratory Standards Institute (CLSI) for Vitek 1 and 2. Results: Most of our cohort consisted of young adult females that were seen at the Emergency Department. E. coli was the most frequent (70.2%) among the 75 species isolated. Resistance of all isolates was ≥ 20% for trimethoprim/sulfamethoxazole (TMP/SMX), norfloxacin, nitrofurantoin, cefazolin and nalidixic acid. Although E. coli was more susceptible (resistance ≥ 20% for TMP/SMX and nalidixic acid) among all of the isolates, when classified by the number and percentage of antibiotic resistance. Global resistance to fluoroquinolones was approximately 12%. Risk factors for E. coli were female gender and an age less than 65 years. Men and patients older than 65 years of age, presented more resistant isolates. Extended spectrum beta-lactamases (ESBL) were identified in 173 out of 5,722 Gram-negative isolates (3.0%) between 2010 and 2011. Conclusion: E. coli was the most frequent microbe isolated in the urine cultures analyzed in this study. There was a significant evolution of bacterial resistance between the two periods studied. In particular, the rise of bacterial resistance to fluoroquinolones was concerning.

Antimicrobial susceptibilities of Listeria monocytogenes human strains isolated from 1970 to 2008 in Brazil

INTRODUCTION: Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. METHODS: Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC). RESULTS: Among the strains tested, serovar L4b (60.3%) was the most prevalent, followed by serovar 1/2a (20.6%), 1/2b (13.2%) and the more uncommon serovars 1/2c, 3b and 4ab (5.9%). All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5%) showed resistance to rifampin, and two (3%) were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2μg/ml reinforce the need for microbiological surveillance. CONCLUSIONS: The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.

Antimicrobial Resistance of Shigella spp. isolated in the State of Pará, Brazil

INTRODUCTION: Shigella spp. are Gram-negative, nonsporulating, rod-shaped bacteria that belong to the family Enterobacteriaceae and are responsible for shigellosis or bacillary dysentery, an important cause of worldwide morbidity and mortality. METHODS: We studied the antibiotic resistance profiles of 122 Shigella spp. strains (81 S. flexneri, 41 S. sonnei, 1 S. boydii) isolated from patients (female and male from 0 to 80 years of age) presenting diarrhea in different districts of the State of Pará, in the North of Brazil. The antibiotic resistance of the strains, isolated from human fecal samples, was determined by the diffusion disk method and by using the VITEK-2 system. RESULTS: The highest resistance rate found was the resistance rate to tetracycline (93.8%), followed by the resistance rate to chloramphenicol (63.9%) and to trimethoprim/sulfamethoxazole (63.1%). Resistance to at least three drugs was more common among S. flexneri than S. sonnei (39.5% vs. 10%). Six (4.9%) strains were susceptible to all the antibiotics tested. All strains were susceptible to cefotaxime, ceftazidime, ciprofloxacin, nalidixic acid and nitrofurantoin. CONCLUSIONS: High rates of multidrug resistance in Shigella spp. are a serious public health concern in Brazil. It is extremely important to continuously monitor the antimicrobial resistances of Shigella spp. for effective therapy and control measures against shigellosis.

In vitro antifungal activity of fatty acid methyl esters of the seeds of Annona cornifolia A.St.-Hil. (Annonaceae) against pathogenic fungus Paracoccidioides brasiliensis

INTRODUCTION: Fatty acids are abundant in vegetable oils. They are known to have antibacterial and antifungal properties. METHODS: Antifungal susceptibility was evaluated by broth microdilution assay following CLSI (formerly the NCCLS) guidelines against 16 fungal strains of clinical interest. RESULTS: In this work, fatty acid methyl esters (FAME) was able to inhibit 12 clinical strains of the pathogenic fungus Paracoccidioides brasiliensis and were also active in the bioautographic assay against Cladosporium sphaerospermum. CONCLUSIONS: FAME was a more potent antifungal than trimethoprim-sulfamethoxazole against P. brasiliensis under the experimental conditions tested.

Symptomatic myocardial bridging or cardiac Whipple's Diseas

This report concerns a patient with articular and cardiac manifestations of Whipple's disease. The disease was diagnosed only when gastrointestinal symptoms had appeared, because all cardiac symptoms were attributed exclusively to myocardial bridging. After 18 months of treatment with trimethoprim-sulfamethoxazole, the patient is fully asymptomatic with a normal echocardiogram.

A Salmonella agona outbreak in a pediatric hospital in the city of Rio de Janeiro, Brazil

Six Salmonella Agona strains from an outbreak of 15 days duration which occurred in a public hospital in Rio de Janeiro, Brazil, were analyzed. The outbreak involved six infants (mean age, 24 days; mean body weight, 1612 g), all of them with severe clinical signs and symptoms. Two of them had surgical implications, two were preterm and two had respiratory distress at birth. The Salmonella strains were resistant to nine antimicrobial agents (ampicillin, cephalotin, cefriaxone, gentamicin, amykacin, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracyclin). Analysis of the plasmid pattern of the wild strains and of the transconjugants confirmed that these were identical strains.

Occurrence of Plesiomonas shigelloides in water environments of Rio de Janeiro city

Fresh and salt water samples analyzed in Rio de Janeiro city showed the presence of Plesiomonas shigelloides. Forty-six strains were isolated from both environments. A high incidence of P. shigelloides was achieved in polluted fresh and salt waters as well as in samples from non-polluted streams. P. shigelloides isolates had biochemical characteristics similar to those already described in the literature. None of the isolates analyzed produced enterotoxin in the suckling mouse assay. Hemolytic activity against sheep and human type A erythrocytes was detected in the strains tested. The results of the antibiotic susceptibility tests indicated that all the isolates were susceptible to the cephalosporins, penicillins combined with a beta-lactamase inhibitor, aminoglycosides, imipenem, norfloxacin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole. All the isolates were resistant to the penicillins.

Serotypes of Vibrio cholerae Non-O1 Isolated from Water Supplies for Human Consumption in Campeche, México and their Antibiotic Susceptibility Pattern

The presence of Vibrio cholerae non-O1 in water supplies for human consumption in the city of Campeche and rural locality of Bécal was investigated. V. cholerae non-O1 was detected in 5.9% of the samples obtained in deep pools of Campeche. Studies conducted in Bécal and neighbourhood of Morelos in Campeche indicated that collected samples harbored V. cholerae non-O1 in 31.5% and 8.7% respectively. There was a particular pattern of distribution of V. cholerae non-O1 serotypes among different studied regions. Accordingly, V. cholerae non-O1 serotype O14 predominated in the deep pools of Campeche and together with V. cholerae non-O1, O155 were preferentially founds in samples taken from intradomiciliary faucets in the neighbourhood of Morelos. Samples from Bécal predominantly presented the serotype O112. 60% and 53.8% of all studied strains of V. cholerae non-O1 proved to be resistant to ampicillin and carbenicillin. 3.1%, 7.7% and 6.2% presented resistant to doxycycline, trimethoprim-sulfamethoxazole and erythromycin respectively. The study showed the necessity of performing a strong epidemiologic surveillance for emergence and distribution of V. cholerae non-O1

Pseudomonas aeruginosa: study of Antibiotic Resistance and Molecular Typing in Hospital Infection Cases in a Neonatal Intensive Care Unit from Rio de Janeiro City, Brazil

This study had the objective of to analyze the demographic and bacteriologic data of 32 hospitalized newborns in an neonatal intensive care unit of a public maternity hospital in Rio de Janeiro city, Brazil, seized by Pseudomonas aeruginosa sepsis during a period ranged from July 1997 to July 1999, and to determine the antimicrobial resistance percentage, serotypes and pulsed field gel electrophoresis (PFGE) patterns of 32 strains isolated during this period. The study group presented mean age of 12.5 days, with higher prevalence of hospital infection in males (59.4%) and vaginal delivery (81.2%), than females (40.6%) and cesarean delivery (18.8%), respectively. In this group, 20 (62.5%) patients received antimicrobials before positive blood cultures presentation. A total of 87.5% of the patients were premature, 62.5% presented very low birth weight and 40.6% had asphyxia. We detected high antimicrobial resistance percentage to b-lactams, chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline among the isolated strains. All isolated strains were classified as multi-drug resistant. Most strains presented serotype O11 while PFGE analysis revealed seven distinct clones with isolation predominance of a single clone (75%) isolated from July 1997 to June 1998.

Evaluation of adherence, hemagglutination, and presence of genes codifying for virulence factors of Acinetobacter baumannii causing urinary tract infection

Acinetobacter baumannii is a strictly aerobic bacterium which causes severe infections, however its pathogenic characteristics are not well defined. Thirteen A. baumannii strains isolated from urine of hospitalized and nonhospitalized patients with different ages were investigated for the presence of virulence factors. The isolates belonged to biotypes 2, 6, and 9 and were sensitive to imipenem. The majority of them showed resistance to amikacin, ceftazidime, ceftriaxone, ciprofloxacin, gentamicin, norfloxacin, and trimethoprim-sulfamethoxazole. None of A. baumannii strains presented genes codifying for 17 different virulence factors previously described in uropathogenic Escherichia coli, when tested by polymerase chain reaction (PCR). Nine isolates agglutinated human group AB erythrocytes, in presence of mannose, but none of them agglutinated group O erythrocytes. Adherence to polystyrene was observed in 7 isolates, and this result did not correlate with that obtained in hemagglutination assay. All the isolates were able to grow in iron-limiting conditions, showing that A. baumannii produces some type of siderophore. However, the genes iutA and fyuA, from iron uptake system of E. coli and Yersinia sp., respectively, were not present in the isolates, suggesting the presence of a different type of siderophore. The fimbriae of A. baumannii strains that mediates the adherence are possibly mannose-resistant, eventhough the mechanism of adherence to human epithelial cells still remains to be elucidated.