Fungal HAIs infections continue to be a major cause of morbidity and mortality despite the current developments in terms of diagnosis and therapeutic options. This study is the first description of the fungal profile of the external surfaces of hospital cockroaches in a Tanzanian tertiary teaching hospital. The study demonstrated that hospital cockroaches represent a potential reservoir of fungal pathogens associated with HAIs. The presence of 7 medically important fungal genera including Candida, Aspergillus, Cladosporium , Mucor , Fusarium , Rhizopus and Pencillum on the outer surfaces of hospital cockroaches are similar to results of other studies conducted in Iran, Iraq and Brazil (4-6). This high fungal carriage rate (100%) is quite significant in terms of its implication with regards to the transmission of fungal pathogens associated with HAIs. Especially considering the habits of these insect, that tend to move freely over various hospital arears. The fact these insects and when feeding, regurgitate food from their crop and may defecate on hospital surfaces, suggests that these insects may have a role to play in the spread of infectious fungal agents. The finding that a high percentage of tested cockroaches were contaminated with Candida sp isolates (57.9%) and Aspergillus sp (23.2%) respectively seems further proof that these insects may vectors for the spread of nosocomial fungal agents. Particularly as considering that the presence of C. pseudotropicalis, C. albicans , C.parapsilosis C. glabarata and C. rugosa , known fungal pathogens. That are increasingly being reported as agents of life threatening and drug resistant HAIs associated with high treatment costs, morbidity and mortality (22). C. pseudotropicalis, C. albicans , C.parapsilosis and C. glabarata , are known to be important causes of blood stream infection in neonates , transplant recipients , granulocytopenic patients and surgical patients (22-27). While C. rugosa is now more and more being recognized as an emerging pathogen of blood stream infections of individuals who are immumocomprised (28).
The isolation of Aspergillus fumigatus and A. niger further supports the finding that hospital cockroaches may be potential reservoirs of major fungal pathogens associated with life threating HAIs infections of immunocompromised individuals. These isolates are known to be major causes of the invasive fungal infections particularly in transplant and Acquired immunodeficiency syndrome (AIDS) patients (25-26). The presence of other known causes of opportunistic and nosocomial fungal infections species such as Cladosporium, Mucor, Fusarium , Rhizopus and Pencillum , further cements the concept that cockroaches in hospitals a may be major public health concern and confirm the findings of other studies conducted on domestic and hospital cockroaches (1-9) . What the study findings indicate is that there needs to be more studies to be conducted to ascertain if medically important fungi on the surfaces of hospital cockroaches are etiological agents of HAIs including of newer fungal pathogens immunocompromised patients such as Talaromyces marneffei (29).
The majority of cockroaches were trapped from the Main hospital kitchen and none cockroaches were captured from the main intensive care unit of this hospital. This indicates that infection prevention and control measures are being to adhered in sensitive hospital areas. However there needs to be concentrated efforts for effective fumigation practices in the food handling areas. Especially considering the fact, that cockroaches carrying drug resistant pathogens may wander from any part of the hospital through the hospital sewage systems unnoticed. Moreover , hospital environmental control teams therefore needs to do a thorough assessment of the resistance of the hospital cockroaches to common pesticides before on deciding what chemicals to use. This is view of recent study findings that have shown that cockroaches in domestic and hospital settings are becoming resistant to common pesticides (30).
Fluconazole has been the corner stone therapeutic option for many African countries in treating fungal infections particularly for vaginal and oral candidiasis. This study found that 16.3% of randomly selected Candida isolates exhibited resistance to fluconazole. This is higher that has been previously reported in Tanzania were it shown that resistance to fluconazole was only 6.8% (30). This finding maybe a warning sign for the continued empirical use fluconazole for prophylaxis and or treatment of systemic or localized Candida infections in African and Tanzanian health care setting as resistance to fluconazole is on the rise (31). The presence of fluconazole resistant Candida sp isolate on the outer surfaces of cockroaches thus clearly suggests that cockroaches can act as vectors to transmit drug resistant fungal strains in hospital settings, especially within hospitals that lack of effective pest control measures
A limitation of this study, is that it only determined only the prevalence of fungal isolates on the surfaces of hospital cockroaches. The study did not use molecular tools characterize the isolates and compare them with isolates of confirmed causes of HAIs infections at this hospital. Moreover, the antifungal susceptibility testing was only done yeasts and using only one drug fluconazole.